Document JrZGoLZnvygKvw0RyvK04QNGa

m* lan be- ,/J. p good o train Jinique. iron and one the s start- sontrob Human Mining Section Executive Committee 1944-1945 General Chairman--C. M. Fellman, The Montreal Mining Co., Montreal, Wis. First Vice-Chairman--C E. McKnight, Labe Shore Mines, Ltd, Kirkland Lake, Ont, Canada. Second Vice-Chairman--E. A. Anundsen, Pickands Mather & Co, Duluth, Minn Third Vice-Chairman--John L. Boardmam, Anaconda Copper Mining Co, Butte, Mont ---- Secretary and News Letter Editor--Daniel Harrington, U. S. Bureau of Mines, Wash ington, D. C. Entertainment Committee Chairman--J. T. Ryan, Jr, Mine Safety Appliances Co, Pitts burgh, Pa. Membership Committee Chairman--*Geokge Martinson, Pickands Mather & Co, Cleve land, Ohio. Program Committee Chairman--J. J. Forbes, U. S. Bureau of Mines, Washington, D. C Mtmbers-at-Large-- J. W. Alt, Calumet & Hecla Consolidated Copper Co, Calumet, Mich. *P. M. Arthur, American Zinc Co. of Tennessee, Mascot, Tenn. Angus D. Campbell, McIntyre Porcupine Mines, Ltd, Schumacher, Ont, Canada. W. H. Counts, Baroid Sales Div, National Lead Co, Texarkana, Texas. R. Dawson Hall, "Coal Age," McGraw-Hill Publishing Co, Inc, New York, N. Y. H. T. Harper, Tennessee Copper Co, Copperhill, Tenn. W. D. Haselton, Pickands Mather & Co, Duluth, Minn. *TL C Hehrie, Phelps Dodge Corp, Bisbee, Ariz. D. D. Mopfait, Utah Copper C6, Salt Lake City, Utah. R. H. Ship, The New Jersey Zinc Co, Franklin, N. J. L. T. Sicka, St Joseph Lead Co, Bonne Terre, Mo. John Teeweex, Homestake Mining Co, Lead, S. D. Howard L Young, American Zinc, Lead & Smelting Co, St Louis, Mo. Staff Consultant--W. H. Forbes, National Safety Council, Inc, Chicago, 111. P*st General Chairman 353 ! PI 1. IT -t. ^ . .T' f1 j-! f/j i ; ;v 1 : 'i ?!? i; ?. \: ' **_ ** ;-i 5:` \ i; [i ti* * r. : PLAINTIFFS EXHIBIT PLAINTIFF'S EXHIBIT * V -- * m: j; ' f $: :- 'V>.! ; r : T 33rd National Safety Congress, 1944 TUESDAY AFTERNOON SESSION October 3, 1944 Presiding: General Chairman, John T&ewef.k, Safety Eng., Homestake Mining Co., Lead, S. D. Some Sources ofErrorin Dust Sampling By A. S. RICHARDSON, J. W. WARREN and W. C. WILLIAMSON Anaconda Copper Mining Co., Butte, Mont. In the measurement of the concentrations of dust that are present in air used for the ventilation of mines, or other working places, it is recognized that the dust is not uniformly dispersed in the air. Also that' under the same atmospheric conditions widely different results may be obtained by the use of different dust sampling instru ments, and by different methods of quanti tation. In dust sampling work done fay the writers with impingers a number of sources of error have been found to exist, and these are here described for'the benefits of others engaged in similar work. Impinger Sampling in a Flow of Air In the collection of any volume of air for dust sampling purposes, it is essential that the number of dust particles in the sample volume be the same before and after collec tion. When the air is not in motion it may perhaps be assumed that this condition exists for sampling with impingers. However, dost sampling in mines is often done in flows of air moving at fairly high velocity, and similar conditions exist in ducts carry ing Bows of air from dust collection hoods. Although nothing tike exact measurement of dust conditions as yet seems possible, it is desirable that the methods of sampling streams of air in motion should be com parable to those taken in still air. Smce dust particles carried in a moving current of air possess some definite directional mo mentum, it is indicated that for tupformity of dust content, the sample volume should be drawn from the air stream without change in the velocity and direction of flow. - In impinger sampling work the most - necessarily be held in a vertical position and with the tube vertical. This means that air drawn from a horizontally moving air stream must be deflected at right angles to its original direction of flow to enter the tube opening The momentum of the hist particles would then tend to continue them in motion past the tube opening, and thus reduce* the dust content of the sample vol ume. To develop the effect of these conditions upon dust sampling results, some tests were made fay taking dust samples from air mov ing horizontally at different velocities simul taneously with two impingers, one having the ordinary vertical trie opening at right angles to the - direction of flow, and the other, being equipped with an elbow exten sion to bring the tube in line with the direc tion of flow. Two samples were, also taken with restricted orifices placed at the elbow openings so as to make the velocity of air passing through the orifice the same as that of the main air stream. Dusty air for this purpose was obtained by allowing a flow of dust, collected at a bag type dust arrester, to fall at a short horizontal distance away from the inlet of a blower. The induced flow of dusty air was then forced through a galvanized Iron duct to the.sampling position. Compensation for variations in dust collection efficiency of the two impinger instruments Used in the test was made by alternating use of the instruments in the two sampling positions. _ Geometric mean diameter of the dust par ticles was 0.65 microns with standard geo metric deviation 2.09, as deteraqined by sam ples taken with an Owens Jet sampler with microscopic - work done fay micro-projector at a magnification of 101,000 diameters. ' i__L Mining Section e Tabulation Na 1 Dost Counts with Impingers Alternated In Two Sampling Positions 355 AirVelodty FL Per Min. High Coaceatntioas ^ImpmgerNo. 3- ImpingerNo. 5 Plot. A' Bos. B Bos. A Pea. B 250 802 250 108.0 250 m2. 250 61.6 Average 793 Per Cent Variation in Instrument Collection 7Ji 81.0 1123 802 6&8 85.8 low Coaceaiztdota ImpingerNo. 3 Impinger No. J Bos. A Pas. B Bo*. A Pa*. B 29.9 27.9 32.0 193 273 352 303 300 250 30.1 935 Tabulation No. 2 Dust counts for Vertical and Parallel Impinger Tube Intakes AAfJfYrlWao-crinhy, ft. Per Min. 250 500 500 750 750 1000 1000 1000 1250 1250 1500 1500 1500 1500* 1500* Aiypti to how * Imp. No. 3 Imp. No. 5 882 43.6 367 9.96 17.1 5L6 642 83.6 373 213 28.4 172 153 34.4 483 Simples Dram Pinllel to Flow Imp. No. 3 Imp. Ne. 5 65.4 903 413 223 46u6 27.6 223 74.0 983 92.0 * 563 51.1 333 743 1103 *& mm drcnlar orifices on impinger sampling tnbes. Pier Crat Right Angles to Plow Parallel to Flow 98.9 96.0 92S 9L6 95.6 61.0 622 763 70.9 72.0 29.9 22.9 46.4 463 492 Plih>nty^ tjf Tmpingwr TllbeS In the taking of a number of dust samples at one time with one instrument; it is nec essary that a number of impinger tubes be used, and variations in the volumes of air sampled by different tubes under such other wise identical conditions is a matter; of some importance. Variations in sample volume may occur because of differences in size and shape of the tube, particularly the size of the orifice from which the air stream is impinged against tire, bottom of the flask. For calibration of the tnbes it is, how ever, necessary to take into account the suc tion pressure; or vacuum, induced by the pump since in the case of compressed air operated ejectors, if seems impossible to obtain exact uniformity in the size of the ejector orifice and this will cause some vari ations in the induced vacuum. In the case of the standard tubes not much variation is shown but in the case of mid get impinger tubes; there are appreciable differences. A maximnm variation of 23 per cent in the volume of air sampled may be noticed for tubes used in two different midget impingers and this is known to be mainly due to variations in the size of the orifice in the tubes supplied by the manu facturer. Midget impinger number one is equipped with a hand-operated, constant pressure pump andMidget impinger number two is equippol with a hand-operated pump delivering constant volume at constant speed. e 356 Tube No. i 2 3 4 Tube No. 5 6 7 8 Tube No. i 2 3 4 S 6 7 8 9 10 D 1 2 3 4 5 6 7 8 9 10 D 33rd National Safety Congress, 1944 Tabulation No. 3 Calibration Comparisons of Midget Impinger Tubes Volume Thru Gas Meter Cu. Ft 1.0 1.0 1.0 1.0 No. 1 Midget Impinger Manometer Reading Vacuum Gauge HrO Time Minutes 1Z1 11.75 11.75 11.80 125 125 12.S 123 9.48 8.40 8.44 728 Volume Thru Gas Meter Cu. Ft 1.0 1.0 1.0 1.0 No. 2 Midget Impinger Manometer Reading HrO Time Minutes 107 656 13.6 750 13.0 7.68 10.3 670 Volume of liquid CC 10 10 10 10 Volume of Liquid CC 15 15 15 15 Tabulation No. 4 Calibration Comparisons of Standard Impinger Tubes Volume Thru Gas Meter Cu. Ft 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 No. 3 Standard Impinger Manometer HrO 372 45.5 325 38.4 35.1 32.6 38.4 36.1 36.0 39.6 425 Time Minutes 474 474 4.75 4745 4.77 4775 474 476 4765 4.72 475 No. 5 Standard Impinger 322 5.165 405 5.15 282 5.16 33.0 5.18 303 5.145 29.1 5.125 32.9 5.17 315 5.17 31.7 5.145 345 5.125 365 5.19 Volume Collecting Medium C.C. 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 75 Flow thru Tube C.F.M. 0.1058 0.1191 0.1186 0.1374 Flow thru Tube C.F.M. 0.1573 0.1344 0.1300 0.1492 Flow thru Tube CJP.M. 1.055 1.055 1.053 1.054 1.048 1.047 L055 1.050 1.049 1.0S8 1.053 0.967 0.971 0.969 0.965 0.972 0.975 0.966 0.966 0.972 0.975 0.963 Mining Section 357 Effect of Dirty Glassware air stream and a consequent deposition of While the effect of the presence of dirt dust on the inside of the tube. Being difficult on glassware used in dust determination work is so obvious that in most cases no illustration of its importance is needed, it of access, this inside tube surface is often given only insufficient cleaning as by hand with the use of a pipe cleaner or tapered is believed, that there are some fairly com brush. mon practices in which lack of adequate The following tabulation shows, for four cleanliness has an appreciable effect upon different samples, the effect upon dust the results obtained. These are related counts of placing a poorly cleaned impinger mainly to the cleaning of the impinger tubes tube in a flask with the usual quantity of and counting cells. collecting fluid and then briefly shaking the In the flow of dusty air through an im flask by hand. thn> pinger tube, the increased velocity of air A method of cleaning the tubes, both motion at the approach to the orifice causes standard and midget that has given satis a reduction of pressure which, with the factory results includes a replaceable fibre accompanying cooling effect caused by evap brush held in a metal shaft that is rotated oration of the collecting fluid in the flask, by the motor of an electric erasing machine, causes a lowering in the temperature of the having a friction grip. Tabulation No. 5 Data Dirty Impinger Tubes Description Midget No. A Midget No. B Stindud No. A Stsndtrd No. B Dust count in 5 Fields before insertion of Impinger tube or Control Count___ _ 2 2 2 2 2 2 2 2 Dust count in 5 Fields after insertion of Impinger tube and shaking-------------_ 38 95 32 56 30 112 38 122 Net increase in Count in 5 Fields......... . 36 93 30 54 28 110 36 120 Depth of Counting Cells and Effect of Settling Time At the present time a wide variety of cells of different design are used to contain the portion of sample collected for counting; A common defect in the Sedgewick-Rafter type is failure to closely seal the corners of vertical containing strips or walls, with the result that leakage or the evaporation of alcohol causes the formation of air bubbles that interfere with counting. Comers of the cell are also difficult to dean. These defects are well recognized but it is perhaps not so well recognized that appreciable variations in the depth of cells also occur. In the case of II cells received from a supply house the variation in depth, as determined by microscope and micrometer was from 0.945 nun. to 1.195 nun. A cell that has been found to give good results is made with the use of a brass ring placed, without any cement, upon a base of non-corrosive glass and covered wtih a coverslip 1 nun. thick. The brass ring is 38 nun. outside diameter, 29 mm. inside diameter and is machined to exactly 1 nun, in thickness. The glass base is 75 u long, 38 nun. wide and 3 nun. thick. The coverslip is 38 nun. square and 1 nun. thick. Since all component parts are sep arated for washing and cleaning, there are no surfaces that are not easily cleaned. An essential piece of equipment for brushing cell surfaces free of air-borne dust before filling with sample fluid is a good camel's hair brush. An illustration of the effect upon dust counts of variations in the depth of.cells is shown in Tabulation number five, which shows the counts obtained from two dif ferent portions of the same samples when counted in two different cells. Cell number five bad an average depth of 0.87 nun. and Cell number six had an average depth of 1.13 nun. :* : II ml if I U'.f ' k^iT.-s 358 33rd National Safety Congress, 1944 Tabulation No. 6 Variable Cell Depth Cell No 5 00344* = 0.87 TTt.tn Ratio No. 8 to No. 6 = 1 to 13 Cell No. 60.0445* -- 1.13 m.m. Cell No. 6 -- 3056 deeper than Cell No. 5 Total Sample Number_________ 1 2 3 4 1-4 Cell Number----------------- 5 6 5 6 5 6 5 6 56 Field Concentration 354 472 308 366 352 401 262 360 1276 1599 Calculated Concentration at 1 m,m. depth ._.......... 407 417 354 324 404 355 301 318 1467 1415 Ratio Concentration in (Vll 1.0 133 1.0 L19 1.0 1.14 1.0 U7 1J0 126 Increase Cell No. 6 over Cell No. 5 in percentage 33 19 14 37 26 Tabulation number seven, below, shows the counts obtained from different portions of the same sample when counted in five different circular cells of the type previ ously described. Tabulation No. 7 Cell No. _ 1 2 3 4 5 Avg. Count ____ 376 405 370 386 390 385 When, as is required for accurate results, two counting cells are filled from each sam ple flask, it is necessary that an interval of time be allowed to elapse between the filling of the first and second cell so that the settling time before the start of the count be the same for both cells. In general, it is well' recognized that increased settling time causes a larger count but it may not be so well understood how much the results are affected by this influwny, j. Tabulation number eight shows the effect upon dust count of allowing .the settling time to increase from 25 to 35 minutes. Tabulation No. 8 Effect of Increasing Settling Time from 25 minutes to 35 minutes % increase in Count *t Guont at Increase Increase 3 min. from 2) min. 35 min. in in Settling Settling 10 min. 3 min. 2fe3t+mltifnig. 14 15 1 3 3.6 18 23 5 23 13.9 33 42 9 43 13j6 38 48 10 5.0 13.1 43 52 9 4.5 10l5 54 71 17 &5 15.8 55 62 7 3S 6.4 61 75 14 7.0 1L5 'V:;: U& fe.'-iTH 1 *ota! 1-4 1599 1415 1.26 26 ; from tatue a in. from J mis. 3.6 !3.9 V 13*. 13.1 105 15.8 6.4 115 Mining Section Control of Electriccd Hazards In Open Pit Mining By P. L. HENDRICKS Chief Electrician, Pickanda Mather & Cou, Hibbing, Minn. Electricity, as a source of power and con trol, was introduced in the open pits ap proximately twenty-five years ago. A large part of the eighty to ninety million tons of ore now going to our great steel plants each year, has been produced or transported by electric power. Safety has always been considered of major importance in the mining industry on the Mesaba Range, and has rated an AAA priority in electrical installations. Many important developments for electrical safely, such as "ground-fault protection," "shidded-type shovd cables," and "indi vidual shovd switch-houses," have been among the fruits of the search for safety. There are certain very definite and posi tive laws that govern the behavior of elec tricity. So long as these laws are not vi olated, electricity in itself, will be more law-abiding than are marry human beings. In electrical installations we are often caught between the economic and physical limitations of low voltage power on one side, handicapped by heavy currents and large conductors, and the hazards of high voltage power on the other, with increased insulation stresses and danger of shock. We have been faced with the necessity of selecting between methods or equipments not of our own choosing, but established by local situations or limitations. Relatively large quantities of power must be transmitted over sizable distances, both vertical and horizontal. Most of the elec trical equipment is portable, and is fre quently shifted from one location to an other, by reason of ore grading, stripping operations, etc The increasing depth and reduced area of the pits aggravate conges tions and transmission problems, and intro duce new problems of pit drainage Most of the equipment is subjected to hard usage and adverse weather, with seasonal -tem perature variations up to 140 degrees. Op erating labor, especially during, the past few years, is often unskilled and careless with equipment Iron ore and surface material are loaded out principally by power shovels which, ex cept for the smaller sizes, are electrically operated. The material is usually trans ported in standard gauge ore and dump cars, or in heavy duty trucks. Railway haulage is powered by steam, electric or diesel-electric locomotives. Heavy duty trucks are propelled by gasoline diesel, or butane engines. Churn drills are common for blast hole and exploration drilling, and pumps, scraper, hoists, tractors, etc, are among the equipment in regular use On the surface there are an increasingly largp number of crushing, washing, jigging, or other ore benefidadon plants, all electri cally operated. Safety Problem The foremost safety problem concerns, the transmission of power to electric shovels. The capacity of the load and the distances involved require voltages rela tively high by safety standards, 2500 or 4,000 volts, depending on local conditions. Because shovels are portable, travel over large working areas on iron ore that is a poor conductor of electricity, and operate on.voltages hazardous to life the impor tance of adequate grounding of the shovel frames against electric shock cannot be over-emphasized. There are three principal ways by which a person may receive an electric shock: (1) Contact with two or more wires of conductors of different voltage or potential (2) Contact between a "live" wire and the earth. (3) Contact between an object charged by accidental contact with a "live" wire, and the earth. The third condition is responsible for a large percentage of the cases of electric shock. Few persons will knowingly take bold of a wire or electrical conductor un less they have reasonable assurance that it is disconnected from the power. But the frames of equipment are assumed to be insulated from the electrical circuits and safe to touch, and there is no safe, simple method of anticipating "charged" apparatus. Although a flow of slightly more than >y'. 360 33rd National Safety Congress, 1944 i/1000 of one ampere of alternating cur rent through the body produces a percep tible shock, and the quantity of current used by a 10 watt lamp bulb would very likely prove fatal, fortunately the human body is a poor conductor of electricity and offers a high resistance to a passage of current Among the human characteristics inher ent in electricity is its preference for the paths of least resistance, or short-cuts. This characteristic is the basis for the most important detail, of any electrical installa tion, namely "Grounding." A bypass or short-circuit is maintained between equip ment frames and the earth. Any leakage current from defective insulation will take the easier path and follow the ground wire, and the voltage on the frame will be kept within safe limits. Desirable Factor Another desirable characteristic of elec tricity causes electric circuits to interrupt themselves on overloads, short-circuits, or other abnormal conditions. We have util ized this to disconnect instantly any ap paratus that develops an insulation break down to the earth. If one unit of equip ment is to be protected, or if selective trip ping is not desired and the entire pit load can be interrupted, the "potential balance" method is satisfactory and lowest in cost This method consists of a suitable combina tion of apparatus that acts as a sort of electrical scales, and will be affected by unbalanced neutral voltages created by ac cidental grounds, and trip out the main oil circuit breaker. In the larger pits, with several units of equipment in service, it is often desirable that ground-fault tripouts be limited to the defective unit only. Selective tripping not only limits the interruption to the defec tive unit but greatly simplifies the job of locating and removing the cause of the trouble. Selective ground-fault tripping re quires a grounded neutral circuit, and a current-limiting resistor or impedance in the neutral return wire at the source. The flow of fault current back through the neutral return wire from the point of insulation breakdown, will be limited to from 25 to 65 amperes, depending on the type of equipment. Hie voltage drop in tiie return wire with such low current values will not set up any dangerous differ ences in voltage between equipment frames and the earth, even for the split-second necessary for the circuit breakers to* open. The pit neutral wire should not be inter connected with the main substation ground connection, to avoid the possibility of surges from high-voltage insulator flashovers or lightning arrester discharges getting into the neutral wire and backing up to equip ment frames. Ground rod resistances are high in iron ore, and the general practice has been to establish the main low resist ance earth connection on the surface, and supplement it by a number of ground rod installations distributed along the neutral wire of the power lines. Individual switchhouses are required for each unit of equip ment to be protected, installed at the point of attaching the power cable to the power line. The switch-house protecting the de fective unit of equipment will trip out in stantly by the ground-fault relay, actuated either by unbalance in phase currents doe to the fault, or by fault current coming in over the neutral ground conductor from the location of the insulation failure. One or the other of these types of ground-fault protection in service in practically every electrified open pit on the Mesaba range, and I do not know of an instance of even slight shock from equip ment so protected. Whh the selective - tripping type of ground-fault protection the ground or neu tral wire becomes a definitive part of the electrical circuit, and a vital link in the protective device. Periodic tests of groundfault protective installations should be car ried out regularly and the results recorded. Such tests are usually done by grounding one or more conductors at a point beyond each switch-house. The individual switchhouses are backed up by a main groundfault trip located at the sub-station. The ground-fault relay here is given a short time lag to allow the individual switchhouses to clear first Its purpose is to baric up any of the switch-houses if they should fail, and also to protect the power lines, eto, against grounds. Outlines Switch-Houses The switch-houses are constructed in sev eral different styles. An oil circuit breaker of ample rupturing capacity Is ordinarily differ- *s: I 0 opea : interground stages rers or tg into ' eqoipces are practice resistce, and ad rod neutral switch: eqnip point : power the deoot in* ctqated its due coming >r from e. pes of vice in pit on v of an rpeof or neuof the in the frotmdbe carcorded, tonding beyond switchgrounda. The 1 short switchto back should r lines, in sevbreafcer iinarily Mining Section 361 indnded, arranged to open instantly on short circuits and ground-faults, with a time-relay on overloads. Gang-operated disconnect switches simplify the job of catting off the power for cable changes, repairs, etc. Suitable terminal connections are provided to facilitate the attachment of the incoming and outgoing power cables. Metering installations are also included wherever power consumption records are desired. All of the apparatus is assembled in small, rugged, portable, weatherproof steel enclosures, with dead-front construc tion. Access to the high-voltage compart ment is limited to the electricians. In die pits using railroad haulage the switchhouses are equipped with lifting bails and handled by the locomotive crane. The switch-houses in pits with trade haul are mounted on suitable skids, and moved by tractors or tracks. They are located as near as possible to the point where the shovel cables attach to the power lines. Equally important to electrical safety is the type of portable high-voltage power cables, used to transmit power in the work ing areas. The type generally used is the rubber-jacketed, shielded, shovel cable, with one or more internal supplementary ground conductors. Considering the conductor sizes and the operating voltages, these cables are -comparatively small, light, flexible, and easy to move about Shielded type power cables have derided safety advantages, especially where groundfault protection is included. The grounded sheath or tube enclosing each individual high-voltage conductor precludes the pos sibility of current leakage from the con ductor to the outside surface of the cable, through cuts or braises in the insulation. Also, because of Are ground sheaths sepa rating the individual conductors from each other, grounds must occur before shortcircuits, in instances of cuts or crushing injuries, and the power will be cut off by die ground-fault protection without the Sash and burning of heavy power arcs. For the 440 volt power distribution to drills, small pumps, etc, a similar type of cable is commonly used, except that the shield ing or ground sheath is omitted. The ground wires in all portable power cables to equipment, regardless of operating volt age, connect to the neutral wire of die distribution system, so that a full metallic ground circuit will be maintained to all equipment Proper maintenance of portable highvoltage power cables is important for safety as well as for economic reasons. Normal functioning of the ground-fault protection is contingent upon a continuous, low resistance, ground conductor through out the length of the cable. A broken or disconnected ground wire in a cable means that the equipment behind the break is more hazardous than if ground-fault protection were not installed. Incipient, damage to conductor insulation withiffthe table should be located and repaired before .'developing into afcomblete breakdown. Whenever any one /conduclor of die distribution system is grounded the insulation on die remain ing two conductors throughout the system is Subjected to voltage stresses approxi mately 175% of normal As a result, if either of these conductors has weakened insulation, just able to hold the normal "neutral voltage" stress the increased elec trical pressure or voltage may break down the defective insulation, and a phase to phase short circuit will develop. The ground wire between the location of the two faults will become a part of the short-circuit, and the excessive flow of fault current may build up a dangerous difference in voltage across that section momentarily, until the circuit breaker opens. Periodic high-po tential tests of cable conductor insulation are advisable to blow out the weak spots before they fail in service. Cuts and braises in the outer jackets should be vulcanized as quickly as possible. Otherwise ground water may get inside of the jacket and set up corrosion in the strands of the ground sheath, and penetrate into damaged con ductor insulation. Great skill and care are necessary in making cable repairs to pre serve the original conductivity and strength of all conductors, and the insulation and watertight qualities of the rubber. Ground wire conductivity and resistance measure ments, and high potential tests on conductor insulation are advisable after repairs. Services Hard Service conditions for portable power cables are unavoidably severe, but full co operation from all of the pit operating de partments can spare the cables from much unnecessary abuse. Care must be exercised 362 33rd National Safety Congress, 1944 in mines using railroad haulage to protect station. The person placing the lock re the cable in crossings under trades against moves its key and carries it with him. material falling from the cars, derailments, 100% compliance with this lockout rule and hot coals and ashes dropped from pass would have, prevented a number of acci ing locomotives. In mines with truck haul dents and near accidents. the cable crossings over trade roads are usually made by the use of portable cable supports that suspend the cables at a safe height over the roads. Here the service is particularly severe because of the hazard of trucks driving over the cables, or pass ing under cable crossings with their dump bodies elevated. Records of more than 25 years of ex perience with electrified open pit operation on the Mesaba Range have convinced ns that the subject of electrical safety is not the private property of the mine electrician, but affects to a greater or lesser extent every employee on the job. The electrician is usually trained and more familiar with Electric power ordinarily is transmitted the proper precautions and procedures. from the substation to the pit boundaries During the past 25 years there have been by overhead power lines, using three power 10 fatalities from electrical causes in the wires and one neutral wire of equal size, open pit mines of the Mesaba Range, and mounted on wooden poles. The pit -or a production of approximately one billion ganization should be instructed on the haz iong tons of iron ore, pins an equivalent ards of overhead lines, since guessing the amount of waste material. dearance to a "live" wire is as deceptive as guessing the dearance to a buzz-saw, and certainly more serious to the person guessing wrong. Adequate short-circuit protection is important, as well as groundfault protection, and pole-top sectionalizing switches allow disconnecting brandies or sections of the line for additions or re pairs. Very few if any of the mines do any "hot-line" work, because of - its ex treme hazard, and because our men are not specialists in such work. The average number of electrical acci dents has not been increasing, although jthe use of dectrical power has increased by many hundred per cent Electrical fatalities represent only a little over 3% of the total from all sources. Achievement of our im proved safety record is the summation of the complete cooperation that exists be tween the electrical departments of the different mining companies, rite all-out as sistance of the electrical manufacturers, and the liberal financial backing of management, Another new hazard has been introduced in all matters pertaining to electrical safety. by the rapid increase in the number and size of the ore-treating plants. Automatic Hazards Anticipated control is essential to provide the necessary The electrical departments endeavor to interlocking between successive units, and anticipate possible electrical hazards, and the conirol stations for stopping and start incorporate every reasonable precaution for ing are usually grouped at central locations. dectrical safety. Every person working Suitable warning signals for starting are where there are any possible electrical haz an important safeguard, with provision for ards should make it his own business to return call from the remote point if feasi be properly advised about-spedal dangers, ble. Emefgency stop stations should be and what to do, and what not to do, if any located at strategic points, and arranged emergency arises. The same is true regard so that they can be locked out Various ing compliance with rules and regulations, methods are provided in the control to such as locking oat controls, use of warn allow a machine to be Ibcked out of service, ing signals, operating equipment* without such as locking-type pushbutton stations, authorization, etc. disconnect switches, etc. Multiple locking Mo matter how carefully the engineering by the different individuals or departments department may plan the electrical installa working on a given machine is advisable, tion, or how. sturdy or dependable the ap to be sure that all persons are in the dear paratus may be built, the continued safe and before the machine can be restarted. The satisfactory operation is. the responsibility problem of padlocks may be met to some of the men who install and maintain the extent by providing a suitable number- of equipment in the mine. I believe many mine locks and individual keys at each control dectridans fail to realize thdr opportune- >ck reh him. of exleradon iced ns Is not tridan, extent rtridan ir with edores. * been in the je, and billion ivalent I acdgb jthe sed by talities e total eenng stallale apfe and ability in the r mine rtuni- Mining Section 363 ties* afforded by the rapid change and ex pansion. We now have electronic and other modem apparatus in service, the operation of which necessitates some rather involved theoretical knowledge. Many of our men would like to learn more about these new tools, but find it difficult to sweat out the information by themselves. Perhaps our educational facilities could be made avail-c able to more men within industry, to help them grow up with their work. Summarizing, landmarks along the road towards electrical safety were as follows: 1. Introduction of rubber covered. shielded type cables for high voltage power distribution. 2. Development of the individual switchhouse, with provirions for automatic fault protection, and switching appa ratus. 3. Introduction of "ground-fault protec tion" to redace the hazards of acci dental grounds and to automatically cut off the defective circuits. 4. Promoting electrical safety in general, by spreading information pertaining to its proper use. THURSDAY AFTERNOON SESSION October 5, 1944 Presiding: Jobs Tkeweek, Safety Eng, Homestake Mining Co., Lead, S. D. Discussion CHAIRMAN TREWEEK: Before we proceed with the regular program, Mr. Forbes of the National Safety Council will answer questions or hear grievances or any thing that you want to put before him. MR. FORBES: In my brief talk yester day I suggested, I believe, that the Mining Section should appoint a committee, and I mean a representative group of various types of mines and mining districts to line up a list of titles for industrial data sheets, from two to four pages; those cover specific subjects, and I would like to have just as many phases of mine safety covered as is possible. As 1 said yesterday, that infor mation must come from men actively en gaged in the industry, or from the United States Bureau of Mines, which is the same, as far as I'm concerned. At the present time the Council has tittle information on mine safety problems. Mining changes rapidly-and methods and conditions vary vastly in the different districts and different types of mines. It's a difficult job to put out information to satisfy the entire mining industry, but if the Council is to be of service to the industry, we must do the best we can to cope with the conditions. It means that perhaps a great many more data sheets will have to be published than may be necessary for some of the other sections in the Council, but I sincerely be lieve that we should make every effort to cover just as many phases of mine safety as possible. I'd like to have a committee to prepare the titles for subjects they want covered, and then sincerely try to get men in the. industry to prepare the information. As I told you, that information is not just pub lished when it's sent in here; it's gone over, and then it is mailed out to many people and committees, to pass on it and criticize and offer suggestions, and it takes a little time to get those things out MEMBER: You have a list of about SO suggested data sheets that we have already presented What we would like is some is-' formation on how to prepare the data sheet MEMBER: Isn't it your thmight thaS1 there should be a source? An operator, for instance; may be doing some new work and he'd like to put in some ladderways that would conform to the best practices. All right; he writes to the National Safety Council and they send him their standard practices on ladderways. That information has to come from the' group .of men who have been putting in what they consider safe ladderways for a good many years. MR FORBES: Exactly. MEMBER: And if somebody else wants some information, possibly on raising meth- 1' d ;1 i| ;! t] .; i J ' /! ' . v y' \ -St; ii 364 33rd National Safety Congress, 1944 ods or something like that, if he wanted to know the accepted safe practice so he can conform to those general practices, he writes to the mining section or to the clearing house of the Council and it can send to those people accepted information on their particular mine safety problems. MR. FORBES: That's just exactly what I have in mind. After all, the National Safe ty Council is only a clearing house for that information. The information must be fur nished to the Council. MEMBER: Mr. Chairman. I have an altogether different idea about rhf? subject I don't believe we need any of these stand ards. I believe that there's been enough stuff published in the proceedings of the various mining sections and the Bureau of Mines so that anybody who wants to find out anything about anything that they want to do can find it there. Mining changes every six months or something like that and I think if you had a good library staff and a fellow wrote in you could say "We will give him a big bibliography where he can go and get the stuff"; that suits me all right. MEMBER: As I understood this, the request has been made and we agreed to comply with it, but because of lack of time we couldn't get into the thing; my thought on it at that time was that what Mr. Forbes wanted was the different ways and means and methods that the different men are em ploying from time to time in doing certain jobs. Now, when we write a paper we may at that time have a particular method that we are following, whereas within two or three months or even weeks we've dooe something that's radically different and bet ter than what was written up. I think Mr. Forbes wants to get that type of informa tion together so that it can be passed out to the other members and if they want to use it, all well and good; if they don't, that's all right, too, but there it is. They'll have access to the experience and the practices of their fellow members in the. mining in dustry. Isn't that it, Mr. Forbes? MR. FORBES: Yes. MEMBER; The way I look at these safe practice pamphlets they should be samedung authoritative, isn't that right? MR. FORBES: Correct MEMBER: In other words, it's not just one company's operations; it's in general. I'm going to tell you of an experience we had. We adopted a code of safe practices for handling explosives about a year ago, and we charged some of the safety inspec tors with the obligation of putting that thing across, and I believe that it's made their work a lot easier and I think we made more progress in standardizing our explo sive practices in the period that set of safe practices has been in effect than we did in any ten years before. I would like to hear the opinion of the fellows using the directives, but it gives us something to fell back on. It's in blade and white, and when we say a thing has to be done a certain way all we have to do is say "It's in the code and you fellows know that and you should be doing it this way." MR. FORBES: If the mining industry is to make satisfactory progress in safety they've certainly got to disseminate infor mation covering every phase of mining safe ty. That's essential. THE CHAIRMAN: I believe we're go ing to be here all afternoon if we don't finish this subject soon. I'm glad to see some of it threshed out MR. DAN HARRINGTON: Not that I want to stick my dim out, but I think it can be clarified a little and I think Mr. Forbes has something which may be of use to you people and to the National Safety Council and to all of us. I think that there are two or three tilings that are involved in this. The data sheets are only one portion. I think that in addition to that there were good points brought out in the discussion by two or three different people. They touched on the fringes of it, at least If there is some good practice--Anderson spoke about a code of safety in connection with blasting--it doesn't matter whether it's in connection with explosives or setting of timber or taking down a loose roof, no matter what it may be, if there is some thing that is extremely good that comes out, why don't you people who know about it, who are doing it, who realize that it is official write a short paper and send it in to the National Safety Council and ask them to publish it in the National Safety News. I don't know whether it can be done, but if it can be done it should be done. The papers needn't be very long--maybe a thou sand words or thereabouts, and that's not much of a job for anybody to write who ice we actives UrO(SlrcC)- ? that made ; made explo it safe re did tike to ng the to fall 1 when in way e code should idustry safety inforJ safe- re go: don't to see >t that link it k Mr. nof use Ivearn ortion. 5 were mssian They isL If dersoa jer it's ing of if, no sameeomes about A it is I it in A ask Safety ; done, i. The l thou* t's not e who Mining Section 365 knows anything at all about writing. If you people would do that you would be performing a service to yourselves and to the industry as well and I don't believe that involves any codes or anything which is likely to get into legal procedures. It's just merely a matter of getting information from one person to another. I think that's one thing that all of you can da We can do it I think that maybe we in the Bureau of Mines have been a little bit remiss ojj that; in fact I know we have. We very frequently get papers from some of our men that are hard to handle with the stereotyped procedure we have of is suing them; but we should send them in to the National Safety News and we wilL I've laid down a little bit on the job on this thing. ` Now about these data sheets. I used to help write them up for the National Safety Council about fifteen or twenty years ago-- more than fifteen years, anyway, and my recollection is that they were merely in the form of hints as to what to do, on threeby-five sheets or something like that You have eight nine or ten hints of what to do in connection with the preparation of, say, a primer, on the handling of the drilling of a hole or handling of a wet stopper or of a dry drill, which I hope are not in existence now, and a lot of things of that kind. Those things don't necessarily have legal connotations. They can be framed in such a manner as to be strictly suggestions or strictly informative, and it seems to me that that sort of thing can be done, but I don't quite see where the industry can do it I think that's really a job for the Na tional Safety Council to da Maybe the thing to do would be for you people to give them suggestions as to what you think, about making up a primer. Where? Should it be made on the surface or underground, close to the place it's to be used? Those are matters of controversy. Many times there are good practices and poor practices and the practice which is good in one place may not necessarily be good in another place. We are confronted with that all the time in the Bureau, bat I do think there are things of that kind which could be done. Certainly you fellows who know about some good safety procedures, some good safety device, owe it to the industry, owe it to your friends, to write it up, get it out, show the other fellow what you are doing and show him what you think he can do to his ad vantage. MEMBER; If I can have just one more word--? CHAIRMAN TREWEEK: We'll give you one more minute. MEMBER: All right I want to tell you men that I consider accident preven tion as a profession, just as highly skilled, though perhaps not as highly paid, as the medical profession or the legal profession; but I want to say this: If we straitjacket ourselves with these safe-practice pamphlets and all of that stuff that keeps us down the line we're going to be in a had way. What's good for Ole and his crowd isn't going to be good for somebody else, and I'm afraid of that if you get too much of that stuff. MR. FORBES: It was never my in tention at any time to set up a standard code for the mining industry. I think I have made it dear that conditions are so diversified that it's quite impossible. But certain essential information pertaining to safe practices in different lines and types of work can be published without harnessing the industry Or harming it in any way. It should be most hdpful to it My sincere desire, while I'm with the Council, is to serve the mining industry. I plead with you for your cooperation, for your assistance and for all the information you can give, so that we can disseminate that informa tion and make it hdpful from one district to another. As a matter of fact I would like to see a very active mining section set up in each district, such as the Lake Superior, which is my idea of an ideal mining' sec tion. If we had those in each state, I sin cerely believe that the safety record of the mining industry would be very, very much improved. Let's see if we can't do that I have been out in several districts and talked about the necessity for such organizations, and some are under consideration at this time. I think we should have a great many more mining sections similar to the Lake Superior mining section. 366 33rd National Safety Congress, 1944 Electric Blasting Underground in Metal Mines LAMAR WEAVER Superintendent of Mines, Tennessee Copper Company, Ducktown, Tennessee The mines of the Tennessee Copper Company are in the southeast comer of Polk County, Tennessee. The ore is heavy sulphide consisting principally of chalcopyrite, pyrite, sphalerite and pyrrhotite often containing 95% combined sulphides of iron, copper and zinc. The ore is a good elec trical conductor, so much so that only a small percentage of the Direct Current return follows the established bonded rail return path. Storage of Detonators The surface detonator magazine is a two room brick building, concrete floor and foundation with 12* brick walls, wood ceil ing and corrugated iron roof painted with aluminum paint One room is for storage of detonators and the other a prepara tion room where portable boxes are filled for movement to the underground supply magazines and the returned unused deto nators are taken from boxes returned from the mines, inspected and hung up for drying. The storage room carries a maximum of 250,000 electric exploders and is 6 feet wide by 26 feet long. The preparation room is 14 feet by 20 feet with 12* brick pardon wall between rooms. Each have a regulation door to an outside platform of truck height above driveway. Transportation of Detonators The detonators are hauled underground once each week. Light wood boxes are provided for trans portation of~"detonators and two or more are required for each level depending upon the amount needed for a week's require ment The detonators left in the boxes are brought to the surface magazine where they are sorted, put in special bins to dry and then reissued after a week or more of sueh treatment The carrying box is of convenient size, 21 inches wide by 24 inches high by 11 inches deep with sections for all of the delays used. Detonators are stored in the underground magazine for issue to the miners by a licensed powder-man, who keeps same locked when not in use. On levels using large quantities of detonators they, are transported and stored in the original 500 detonator case. The underground detonator magazine is preferably near the dynamite magazine for convenience of the user and the powder- man. Detonators are issued to the miners in small wood carrying boxes of a size to carry one 50 detonator box or the equiva lent loose. The box has a top and a carry ing handle. Detonators are issued to loading men or trammers (who do block hole blasting throughout the shift) for storage near work ing place but the stope and development drillers are required to wait until they have drilled oat for the day and they know exactly the number of detonators and quantity of dynamite needed. In all cases the unused explosives must be checked bade in to the magazine tender at the end of the shift, except dynamite sold to contractors in case lots. Their unused dynamite is stored in a standard, wood magazine which must be kept locked. Blasting Precautions Grizzly blasting and a small amount of other drilled hole blasting sack as a missed hole is done any time during the working shift. However the shots are not heavily charged and are usually-few m number as determined by mine Supt, mine Foremen and the State Mine Inspector. (In accord ance with the Torn, law.) The maga zine tender is licensed and given authority to see that the explosive act is complied with. A water spray is directed toward all blasts fired during the shift The sprays are turned on after the shot or shots is connected and is left on until the shot-firer returns after the blast This spraying minimizes the amount of dust and smoke produced at its source. e in tiie d the keeps levels eyare al 500 ane is se for >wder- ers in ize to quivacarry- ien or asting workpment they they oators In aD st be der at mV J wood mt of nissed irking leavSy ter as remen ccordmagahority nplied award The ot or til the This dost Mining Section 367 Blasting current is obtained from the following sources: 220 volt alternating current, 250 volt direct current trolley wire, and electric blasting machines rang ing from SO shot down to the 10 cap hand twisting machine. Blasting machines are preferred for* de velopment work due to the progressive nature of the work and the 220 volt A.C. power circuit is preferred for more per manent stations such as loading places un der stopcs and for stope blasting by the drillers. Where power circuits are used we have found it advisable to have an unusually well protected switch with an air gap of 18' or more not offered in the stand ard switch. This is due to the moisture and conductivity of the ore dust which will evenotally cause almost any switch to leak. We have substituted a very eas ily made switch. The firing cable is a duplex rubber covered No. 16 copper wire. This cable, installed on insulators, con nects to copper terminals mounted on a V-pointed, 3 foot long wooden paddle known as a "Shooting Paddle." These shooting paddles are located a safe dis tance from the place to be blasted, and hung so as to prevent contact with ore, rail, pipelines or other conductors. Firing the blast is accomplished by inserting the pointed end of the paddle into what is known as a "Hot Box." The hot box is provided with live alternating current or direct current terminals. The conductors from these boxes connect to the power source. When 220 volt alternating curRUt.is used, tins circuit is fused and con nected in series with an 8 ohm resistor and when 250 volt direct current is used, the current is limited by a 25 ohm re sistor. The other type switch used for firing outside or from points underground near the mine shaft and at a designated firing time, such as stope hole blasting in heavy sulphide ore where the dust is explosive; is the magnetic switch, located about where a paddle switch would be. The magnetic switch is actuated by current over a two wire lead from either a push down multiple-shot firing unit or from an other source of alternating current From either power source the current travels over the No. 16 copper wire du plex rubber covered shooting cable to a 2 pole, double throw knife blade switch which is called the safety switch. This switch when thrown in "off" position shunts the portion of firing cable toward the shots that are to be connected. Each working place is provided with an inde pendent firing circuit and paddles and panel switches are plainly marked, for the places to which they are connected. The safety switch is located as near the place to be blasted as safety will permit, usu ally around the' first comer or right angle tarn and the shooting line switch bade far enough for comfort or safety from a dust explosion. Where a magnetic switch system is in use it saves material to use- a common switchboard near foot of manways, then all these circuits can be energized by one feeder and each place where blasting is desired can be connected to the power line by putting that switch in the "on" posi tion. Maintenance and extension of the shoot ing line is done by the drill man. Safety Switches The safety switch is inspected before entering a working stope or loading place to see that it is in the "off" position be fore Tgoing past it There are a number of other precautions to take in charging boles before connecting lead wires for blasting; i.e., charge holes by- applying pressure with a wood pole, connect leg wires for each round in series or seriesparallel then make connection to perma nent leads, breaking shunt on one de tonator at a time add connect same so as to avoid naked end of wire from becom ing grounded. Check wiring to see that everything is in order. It is always ad visable to check each round with a cir cuit tester or galvanometer for circuit, as well as grounded leg-wires, particularly, when blasting in heavy sulphide ore. Training of all mining personnel in the efficient and safe use of explosives is profitable. In addition to the older man teaching a new-man by showing and do ing the work if has been found that aids such as a demonstration board where actual conditions can be approximated, help a foreman and electrician get over ideas better. The film strip and sound is an- 368 33rd National Safety Congress, 1944 I other tool to help get over to all miners Installation by electrician_______ 6.00 the recommended methods. Discussion There are inherent hazards with electric detonation in metal mines but it is gen erally conceded the preferred method of firing shots. The practice of connecting a number of shots in series involves consideration of the possible hazards of misfires and premature blasts. Abrasion of leg-wire insulation and exposed bare splices between detonators and at lead wire connections give points in the circuit from which the firing current can leak away and cause misfires. There is also the possibility that stray current can enter at these same points before the blast ing circuit is closed and thus cause pre mature blasts. Experience has shown that measurement of voltage is not the sole criterion of the hazard of premature blast from stray cur rents because resistance and other factors can limit the current flow to a value below that necessary to fire a detonator. The minimum current necessary to fire an ordinary electric detonator with cer tainty is approximately .34 ampere. The resistance of an electric detonator varies according to the length and size of the leg wires used. Therefore the minimum voltage required to cause the minimum fir ing current to flow will depend upon the total resistance of the detonator, Le^ re sistance of the bridge wire plus resistance of the leg wires. A common value used for this minimum voltage is 1# volts. Cost of One Electric Blasting Station Average Length 500 Feel For Slope or Development Work. Total cost------------------------ $31.95 At a Grizzly or Secondary Place 8 holes at 50c$ 4.00 5 wood plugs at 5c-------------------- 025 1 shooting paddle----------------------- 020 1 safety switch (open-pole double throw) ----------------------- 0.85 1 safety switch box-------------------- 020 1 hot box -------------------------------- 020 1 25 ohm resistor----------------------- 025 3 support plugs at 25c----------------- 075 100 ft reinforced lamp cord at 1.5c----------------------------------- 120 1 Nailit knob at 02c------------------ 0.05 Installation by electrician------------ 4.00 Total cost----------------------- -$1375 Operating costs for all mines of the blasting materials consumed in mining 1,090,613 tons of ore and 223152 feet of development footage totaled $115285.70. The dynamite cost was $84,973.00 and the electric blasting supplies was $30,412701 The electric detonation cost was 2626% of the total cost and the pounds of dynamite used per electric detonation was 220 lbs. or about 6.4 sticks of 154x8 dynamite. Summary details of costs used are: Dynamite 15321 cases (766,050 lh) ................. $ 84,973.00 Electric caps 332,489....... Annunciator (lead wire) wire O.OTR the _ .................. Reinforced lamp cord (No. 16 copper wire) 19365 feet_____ 5w{tdiiMi 12f . 15 Blasting Mach*"** 1 ............. 25,992.95 3.651.01 417.16 1Q528 225.00 2L00 t Je i i t t l 1 i t t t c t t 3 s c c ( t s s i i 28 holes at 50c each_$14.00 24 plugs at 5c___ ______________ 120 1 shooting paddle 0.50 1 safety switch (open double pole double-throw) 025 1 safety switch box 020 1 hot box0.50 3 support plugs at 25c 0.75 500 ft reinforced lamp cord at 12c 720 3 Nailit knobs at 5c 0.15 Total $11538570 Recommendationa Electric detonation is recommended in metal mines but necessary precautions must be followed. The safety from stray current would be greatly improved if the D.C single trolley wire was eliminated. Two pole trolley or battery locomotives have been recommended as offering a pos sible solution. O tA n o v> < a w a a . , w t r r s?v M t i m 6.00 4.00 025 OiO 0.85 0.50 OiO 025 075 liO 0.05 4.00 *1375 of the mining feet of 5,585.70. and the J.412.70. 36% of ynamite L30 lbs. lite. re: 4,vJ0 5,992.95 3,651.01 417.16 105iS 225.00 21J00 5,38570 ided in stations a stray l if the ninated. motives ' a pos- Mining Section 369 Discussion of Paper MR. DAN HARRINGTON (U. S. Bu reau of Mines) : In the first place that pa per has in it an immense amount of meat There are in it many things for metal min ing people to look at They have had an explosion down there of metal mine dust not coal mine, and it was a serious one, and they are using electric blasting. They are using electric blasting in a mine which prob ably has more stray currents in it than in any other mine in the United States. At any rate we don't know of any mine in the United States that begins to approach the amount of stray currents that they have. Another thing, they are going to ditch the trolley system. Personally I wish every metail mine in the United States and every coal mine in the United States had condi tions so they would all have to ditch the trolley system, and the day will come when you're going to ditch the trolley system whether you like it or dislike it The pro cedures which they have followed out in connection with their electric blasting are certainly something for you people who are here from other regions to take into con sideration. There are a lot of advantages in electric blasting, although many times there are some disadvantages and electric blasting is by no means foolproof. It entails respon sibilities and plenty of them. MR. MORGAN (Hudson Coal Co., Scranton, Pa.): Did you ever have your power cut off the mines and then test for stray currents? MR. WEAVER: Yes, we spent about a year on tests on off-shifts, Sundays; we did it week after week. We operate three gen erators, one 100 and one 150, and then we have; about five miles away, die smelting plant We have 500-volt car locomotives. I was afraid of them. I thought that stuff goes all over the country and probably that was it So we tested that and we trailed it down definitely, and it was entirely due to our owrt jnine trolley system. With one you'd get circuits in one direction and then operate dm other one; you'd get it the other way. We have potential differences on die surface a half mile from the mine of a volt or two volts from the day, fifty feet of wire over here in the day to die pipelines; then when the generator is shut down it's all dead. MR MORGAN: I know. We shut down but still we find it We might have a differ ent system on our ground hookups. What I was thinking about was your pipelines in the mines--around those pipelines, probably on the surface some place; that's what I was thinking. MR WEAVER: That's right MR VICKERS (Casting Mining Com pany, New Hampshire): I'd Just like to ask Mr. Weaver what method of grounding he uses for return circuits. MR WEAVER: We have just the bonds and the rails and in the shaft an independent turn line of four times past the field. MR VICKERS: Do you run continuous tests on your rail joints in these bonds? We all know rail bending joints are a long way from being a good bond system and we have run into experience of stray currents, as well as everybody else in the iron district We finally came to the conclusion that un less the rails are welded into a continuous return circuit the bonding is a long way from being efficient and because we didn't have continuous welded rails we resorted to carrying an extra copper return circuit alongside the drift and we cut over into our track every hundred feet, tying all our air lines, water lines and this return copper cir cuit into our rail system and by doing some of those things we have eliminated to a great extent a lot of our stray currents. MR WEAVER: I'm sure of that, Mr. Vickers. We have had that same experi ence and same belief on bonding. We real ize that Every five or six hundred feet we tried to group into the ore body again. We smelted, drilled a bole in to the ore and made connections there and tied up the pipe lines. I believe we get about ten per cent coming bade through the bonds and we used, just as a check, the ore body; at a thousand feet we used copper wire return. The only way we could get more than ten per cent in power to come back through a copper wire on insulate ore was when we jacked the locomotive up off the trade. Ninety per cent would go back through the ore instead of coming back on a copper wire. We ran a test at a thousand feet just to see how much we could get to go back. i'.'-i'-iO i: MIS MS I.'. , 370 33rd National Safety Congress, 1944 MR. VICKERS: It seems to me from it particularly , important to keep all of the what you say that your return circuit there blasting leads insulated from the ground was highly inefficient, because if you had and from die fail return system. That capacity enough that type of circuit, with is the first stop in protection in stray cur your locomotive on the rails and cross-con rents from our experience--to reduce by nections enough Iran your rails to the cop every means, cross-bond, put in all "the re per, you're certainly going to take it back turn feeders yon can, tie all the metal parts easier through the copper and the ground; together, and have all rail returns, pipelines, there's no question about that Years ago I tugger cables, machine parts, and everything used to think that a pipeline was a good re else all bound together with a good heavy- turn circuit; I have found out to my sor copper conductor. row it's not Every screw joint in the pipe line is a high-resistance joint and it just may be resistance enough, to cause a poten tial difference of half a volt, but if you take a hundred joints you've got quite a voltage built up there. It's going to tend to sneak a lot of your current around and it's going to try to find its way bade through other sources, so the thing is to cany a good metallic circuit back and to have it big enough, get enough capacity there, and I'm sure you're going to get away with a lot of your stray currents. In other words, con fine those currents to the proper return cir cuit. They won't take the ground if they can get a good type of circuit bade. But I agree with you if they don't have a good copper circuit back they're going to get all off. MR. ZELAND (Tennessee Copper Com pany) : We've been in this stray currents a lot There's practically no resistance in our ore. That's on account of the size of this ore body which has been one of our trou bles, and we've been into that a long time. The next step is keeping the stray cur rents out of our blasting circuit Our method has been die use of rubber-covered cables, which have an extra amount of insulation. We use those from die lead wires all the way through just as dose to.the blasting as possible, and that will depend on the nature of die material. From dure to the blasting face we use a heavy weatherproof connect ing win, properly supported. We don't have to worry about stray currents from the ground because of the high resistance. Our ground is an insulate ore; you might say. We have to watch out We don't beat across any pipes or tagger cables or equipment of' ary kind. The last step is the use. of blasting switches and type of connections and so on that will make your circuit as safe as possi ble if stray currents do .get in. We lave a little different procedure than we ever have used. We have a blasting switch. We have a double-pole switch that we fire the blast with. We don't have to get out of the mine We have to get bade a safe distance from MR. RICKS: We've made quite a'study flying material and at that point we have of stray currents and protective blasting sys this double-throw switch in ' the' normally tems for a good many years. We started open position, which is held open by a spring out about twenty years ago with an unfor and by gravity both. The blades are short- tunate accident and we believe that there are circuited similar to yours, but they are short- three different steps involved in protection circuited automatically; you can let go of against stray currents. One is that one just the handle in ary circuit position. That under discussion, the matter of reducing the maintains a short circuit on.the lead cable amount of stray currents present As Vick If the lead cable is long you can be a long ers said the better your return system is, die way away from your noise.. Then we put in less stray currents you're going to have a supplementary short-circuiting switch on coming back from the ore; or the less differ the lead wire somewhat similar to yours, ence in voltage you are going to lave be and because the resistance of the lead wires tween the ends of yoor rail and die adjacent would destroy a great deal of protection, drop, and I mentioned the other day from ahead of the blasting switch we have a cir our experience in mines iron ore is just die cuit break that is also normally held open opposite from your ore. It has a very high by its spring' Just for the .mutual satisfac- resistance so there isvery little by-pass cur >.don of the miners we- use a removable rent taking the actual ore pathl It doesn't jumper betwen the circuit-break and Mast take very much to fire a cap. That makes ing switch that they can cany with them. m m 4 11 oi wi M th 35 m dt ax fit 01 th wi g> dt hi 26 so d* at a be ot re to fii in ax sa hi m th 0 >f the f cnrce by je reparts times, /thing heavy ' curethod ables, ation. ' II the ng as nture isting mectbave i the Our : say. cross at of- isting so on MSSiave a mine, from have tnally pring horthort!D of That able, long mt in h on ours, wires Mian, i dropen sfkcvable rfastthem. Mining Section o . $71 It breaks the wiring section from the power line. They can take it in the powder bag or lock it up inside the blasting switch but there's a definite break between the blasting circuit and power supply which they can see and understand and reach. We don't have the cross-conditions so from an electrical standpoint that's unnecessary. It's just for the miners' peace of mind. These switches are locked and they're so locked that this short-circuit condition has to exist before it can be locked. Hazaras Observed in Western Meted Mines By CARL BELSER Mining Production Security Division Engineer, U. S. Bureau of Mines, Salt Lake City, Utah Introduction Tweny-four of the 76 coal- and metalmining engineers appoioted.as field engineers under Civil Service. regulations were as signed to District H, which embraces the 11 Western States and the western parts of South Dakota and Nebraska. Since August 1942; 741 original inspections were made, and reports were written, as of May 1, 1944, on mines, other than ctxal, and their associated plants, in District H. Also, 351 ronspections were made of 242 of the more important properties. The total pro duction, In 1943, of the mines impeded amounted to about 116,232,000tons of metal lic ores and 17,176,000 tons of sum-metallic ores.. The totid number of employees at die properties inspected'.averaged 65,400, of which number 26J360 were employed under ground and 39,040 on the surface. The acci dent-frequency rate in 1943 varied from a high of 237.4 m an underground mine having 260 employees to a low of 227 In a large smdter having 1,300 employees. In an undeground mine laving 1,600 employees, the accident-frequency rate averaged 14.0 over a 5-year period.' Several small mines have been operated during the last :5 years with out a lost-time injury. Following the inspections, 7,567 written recommendations were made; 1,108 pertained to the safety of the employees, 4,835 to fire prevention, 1,642 to handling and stor ing of explosives, 'and 982 to preventing any interruption or delay in production from sabotage or subversive activities. Several hundred oral recommendations were also made, most of which were adopted during the course of the inspections. Of the 741 mines and plants inspected, 75 (10 per cent) of the facilities are in a class that employs more than 250 persons; 185 (25 per cent) are in a class that employs 40 to 250 persons; and 481 (65 per cent) are in a class that employs fewer than 40 persons. Hazards to the Health and Safety of Employees . Accident records were not kept at 9 per cent of the operations. Many operators were unaware of the frequency, and the se verity of the accidents and. were., in. doubt as to the ability of the various bosses to prevent such accidents. Twenty-one of the smaller mines did not subscribe toany form of compensation insurance. Dust hazards were observed in some dry sections of.under ground mines, around grinding units in ce ment plants, and at dry-drilling operations in quarries, pits, and underground mines; and in most-instances respirators were not pro vided. ` In 19 mines having extensive and compli cated workings, signs had not been .posted showing the direction to the escapenays; first-aid supplies were partly or totally lack ing at 68 properties; and first-aid training was considered insufficient at 187 (25 per cent) of the operations. A few small mines, situated 50. to 80 miles from the nearest doctor and without telephone or telegraph facilities, had no first-aid supplies, and none of the' employees had been trained in first aid. At a -number of properties men were em ployed in occupations .that were hazardous to the eyes and were, without the protection of safety goggles.- Insufficient guarding and screening of machinery, .open stairways, and open grizzlies were noted, at 117 plants. At 32 properties company employees (fid not inspect vital, machinery, such as hoists, 372 33rd National Safety Congress, 1944 hoisting ropes, compressors, boilers, and wind, overspeed, and loose-brake controls. electrical equipment Proper ladderways Safety organizations were recommended were not provided at 32 mines, and at sev at 16 per cent of the properties. In most eral small mines ladderways consisted of cases labor-management safety committees boards nailed to the bottom of bucket skids. were recommended, and regular safety or Ladders in some mines were leaning back ganizations, supervised by trained safety ward from the vertical, insecurely fastened, engineers, were suggested for some of the or not maintained in safe condition. In one larger properties. Most of these larger prop mine the wooden bucket skids extended down erties now employ safety engineers. At sev 300 feet along the 65-degree dipping foot- eral properties the employees seemed to - wall of an open stope. Pieces of 2- by have no regard for their safety. General 4-inch lumber, nailed at about 3-foot inter safety rules and instructions were lacking vals to the bottom side of the skids, pro at 103 properties. Thirteen small mines and vided the only means of egress. In a large four medium-size mines were found with mine a ladder was not available in the only one exit. lower 200 feet of a vertical shaft being Timber was found unsafe or inadequate at stink. 35 operations; unguarded trolley wires at Unsanitary latrines, accumulations of gar crossings where the wire was less than 6% bage and other refuse near the cook house, feet above the top of the rail were noted or polluted drinking water was found at 25 at 9 mines. Thirty-one mines were inade properties. At one small property, 85 miles quately ventilated; however, all operators of from the nearest railway, a number of men medium- and large-size mines were alert became "run down" and "all in." Mine dust to the lost efficiency caused fay poor ventila was suspected as a probable cause, but the tion and were eager to consider any sug state mine inspector found no dust hazard gestions made by the inspectors. to support this conclusion. The sickness was diagnosed as lead poisoning, and several men were awarded compensation; however, the source of the so-called lead poisoning was traced to a spring that contained arsenic Manganese poisoning was prevalent'at two The following miscellaneous accident hazards were observed at various properties: 1. Miners taring fuse through explosives; blasting lines closely paralleling power lines; and unlocked blasting switches. mines. 2. Employees in the mine tiffing on top Living quarters varied from tents to mod of locomotives; cars bring coupled or un ern houses, and the living conditions at some coupled while in motion; and motormen properties were not conducive to the proper making "flying" switches and failing to re rest, relaxation, and cleanliness of the em duce speed and to sound warnings when ployees, resulting in increased unrest and approaching blind curves. labor turnover. 3. Men in man-trips jostling each other Men were observed working under loose and jumping off the man-trips while the rock in drifts, stopes, and raises at several cars were in motion. mines. Fume hazards from mercury retorts were prevalent at a few mercury plants. Adequate mine rescue equipment was not available at 18 large and medium-size mines. Hard hats were worn by the employees in almost all underground mines, but safety-toe 4. Cars and loose muck left standing too dose to shaft collars. 5. Insufficient dearance for locomotives; inadequate shelter holes; and too much spillage along haulage trades. shoes were not as universally worn. Some 6. Gasoline-powered locomotives used un shaft openings, both on surface and under derground. ground, were not provided with safety bars, and some loaded man-cages were handled without the use of safety gates. 7. Man-cages not equipped with bonnets or safety dogs; guides, shaft pockets, and shaft timbers in need of repairs; and sev The hoisting equipment varied from crude eral shafts equipped with only one method gasoltne-engine-driven, friction-dutch hoists of signaling. to large direct-current-powered hoists, which 8. Small, tugger-type hoists used for were equipped with generator-voltage, over hoisting men. trols. nend| "I ! ity orsafety of the r prop\t sevaed to general lacking les and 1 with oate at ires at an 6J4 noted inadetors of t alert entilay sug- xident erties: jsives; 'lines; ms**} w) nrirusn to re- when other le the ng too itives; much ed tm- nnnrtc s, and d sevaetbod d for Mining Section 373 9. Improper mining methods, such as un filled stopes, too much ground opened up, and caving banks overhanging power shovels. 10. Unsealed cliffs overhanging bunkhouses, and insecure scaling ropes. 1L Safety belts not provided for men working over unprotected openings. 12. Shaft sinkers without bulkhead pro tection. 13. 'Electric equipment and cables not properly grounded. 14. Dangling wires and protruding timber and spikes in drifts, crosscuts, and man ways. 15. Proper antidotes not provided where chemicals were being used or processed. 16. Boilers not equipped with a safety valve; a huge ventilating fan being oper ated in such a maimer that children at play could be caught in the-machinery. 17. No protection, provided around the surface openings of caved stopes and aban doned shafts. Holes in floors which might cause a sprained ankle or broken leg. 18. Excessive tailings allowed to accu mulate on mill floors and as much as 4 indies of rock dust allowed to accumulate on. stairways and runways. 19. large bunkhouses provided with only one exit, and new cotripany-owned school houses without "panic" exit provisions. Fire Hazards Fire-alarm systems were not provided on the surface at 17 per cent of the properties, and emergency alarm systems were not pro vided in 101 mines. Prqper fire doors had not been provided in 83 mines; fire drills were recommended at 252 (34 per cent) of all properties inspected. Operators of small mines were requested to instruct keymen in the use of available equipment, and the operators of large mines were requested to organize fire-fighting crews with an ex perienced man as chief. Definite plans of procedure were also recommended in case of underground fires. Some superintendents at large mines had no idea of the type of fire extinguisher to use on each class of fire. The difference in the fire-fighting ability of a well-trained crew and an untrained crew was fully demon strated at surface fires at three different mines within six weeks. At two fires, trained crews quickly cut their way in and fought the fire at its source, and the fires were subdued with relatively little damage. At the third fire, an untrained crew fought the fire by playing streams of water on the out side of the building. The building, valued at more than $200,000, was completely de stroyed. An inspector who investigated ail three fires believed that the third fire could have been fought successfully by a trained fire crew. Gasoline was used for cleaning at 85 mines and plants, and hazardous methods of stor ing gasoline were noticed at 54 properties. Waste paper and trash are often burned in piles near buildings. During the inspec tion of one large mine, a pile of papers was being burned near the frame warehouse, which was not enclosed below the floor line, and a burning paper was blown un derneath the warehouse by the wind; the warehouse is now enclosed below the floor line, and a properly screened incinerator has been provided. The fire-fighting equipment had not been properly maintained at 151 properties, and inspections revealed many unsatisfactory conditions, such as stiff and rotten hose; an inadequate supply of wrenches and nozzles; lost, empty, or broken fire extin guishers; broken hydrants; and stuck doors to hose houses and stuck control valves. The office records and maps of a large mine were recently lost in a fire because a con trol valve in the fire line stuck. Hazards in Handling and Storing Explosives Explosives control embraces proper stor age, transportation- and handling of explo sives. In nearly all the mines inspected, conditions were found to be below the re quired standards. A number of small mines were visited at which no provisions had been made for storing explosives. Unprotected explosives create not only a dangerous sabotage hazard but also a serious hazard to children and to people hot accustomed to using explosives; each year many children are lolled or partly disabled for life while playing with blasting caps. An underground magazine in a large mine contained 2,260 pounds of dynamite, 45 per cent strength. Seventy-five empty wooden w;. yy rli.-' ' i explosive cases and the paper linings from about 150 cases were piled against the wood en front of the magazine. In contrast, explosives are transported, at a large mine, in special trucks from an isolated magazine to the shaft. The ex plosives are loaded into wood-lined cars pro vided with wood-line steel lids. All hoisting of ore and waste is suspended while the explosive cars are being lowered to the various levels. On the levels the explosives cars are coupled to a train consisting of a storage-battery locomotive and three empty cars, and the explosives are then transported to the magazines. The explosives magazines are L-shaped and built in firm ground. In each magazine cases of explosives are stored on a raised concrete shelf covered with 1-inch boards. Near the front end of the "L" is a 12-inch concrete wall contain ing a doorway fitted with a steel door which is suported by heavy-bolted hinges. Barred ventilation openings, 8 by 12 indies in size, have been left in the concrete wall on each side of the door. Each magazine is ventilated by compressed air, which is blown through small holes in a perforated pipe. Fuse is made up on the surface in a special fuse house, provided with barred windows and fluorescent lights. The capped fuse is trans ported to the various levels in special con tainers. The fuse magazines are gunited and have sand floors. Wooden racks are pro vided to support the capped fuse. Electric detonators are stored in wooden boxes with hinged lids. Some detonator magazines are provided with .sprinklers, and hot maga zines are cooled with compressed air. A record of the amount of explosives handled and stored during each shift is kept on the printed forms available in each magazine. The count in all 17 underground explosives magazines was found to tally with the actual amount of explosives on hand. Conclusion A study of the 242 properties reinspected indicates that 171 of the 2,719 original rec ommendations were not applicable. After deducting the inapplicable recommendations, 2,052 (80.6 per cent) of the recommenda tions have been placed in effect At many plants the construction of much needed oil houses, the establishment of mine rescue stations, the removal of otd and useless frame buildings, and especially a marked improvement in housekeeping, result ed from recommendations which were great ly desired by the local management The two tables indicate the number of operations at which each class of hazard was found but do not represent the num ber of written recommendations. At some operations several hazards of similar type were noted. A single recommendation some times embraced several hazards. II 1 i; l. i< 1! n i: li 1! 21 2 Z Z Z 21 21 < i 1 < 1( 11 V lectric s with ir. A inched m the latine. osives actual pected J rtcAfter itions, tenda- much ' mine 1 and illy a result* great er of tazard numsome type osome- Mining Section 375 HAZARDS TO HEALTH AND SAFETY OF EMPLOYEES IN 741 WESTERN MINES TYPE OF HAZARD NO. OF NO. OF NO. OF SMALL MED.-SIZE LARGE OPERATIONS OPERATIONS OPERATIONS TOTAL I. No Accident Records Kept............................ 2. No Compensation Insurance Carried........... 3. Dust Hazards.................................................. 4. No Emergency Exit Signs......... .................... 5. Insufficient or No First-Aid Supplies.......... 6. No First-Aid Training................................... 7. No Goggles Available................................... 8, Screens and Grizzlies Not Guarded............... 9. No Inspection of Machinery.......................... 10. Improper Ladders ........................................ 11. Improper Sanitation ....................................... 12 Poor Living Conditions................................ 13. Working Under Loose Rock.......................... 14. Exposed to Mercury Fumes.......................... 15. No Mine Rescue Crews................................. 16 No Overwind and Overspeed Control...... 17. No Protective Clothing................................... 18. No Safety Bars and Gates at Shafts.-------19. No Safety Organisations............................... 20. Safety Consciousness of Employees........... 21. No Printed Safety Rules............................... 22 No Second Exit.............................................. 23. Miscellaneous Safety Requirements............. 24. Inadequate Timbering in Mine Workings.. 25. Unguarded Trolley Wires.............................. 26. Inadequate Ventilation ........................ .......... 29 21 5 7 57 118 17 54 14 19 16 5 20 6 0 29 14 8 36 4 59 13 82 21 2 11 36 7 00 13 2 84 10 1 57 12 11 5 45 18 12 6 94 6 3 73 95 20 11 7 29 2 84 10 3 63 16 11 2 36 8 40 47 28 86 34 13 7 72 21 20 19 68 187 33 117 32 32 25 15 34 8 18 60 26 21 115 17 103 17 157 35 9 31 667 468 157 1,292 EXPLOSIVES HAZARDS TYPE OF HAZARD NO. OF NO. OF NO. OF SMALL MED.-SIZE LARGE OPERATIONS OPERATIONS OPERATIONS TOTAL 1. Improper Storing, Transporting, and Handling of Explosives...................... ... 430 162 67 659 HAZARDS FROM SABOTAGE AND SUBVERSIVE ACTIVITIES .1. Absenteeism and Labor Turn-over.......... IS 7 11 2 Compressors and Fans Not Guarded.... . . 22 26 13 3. Fences and Gates Not Provided............... 43 19 4. Finger Printing Not Required................ .:. 7 8 21 5. No Identification Cards and Badges........ 0 12 3 6 Employees Not Investigated............. ....... ... 37 54 37 .7. Inadequate Illumination on the Surface.. 27 24 27 8 "No Trespassing^ Signs............................ 17 0 9. Vital Machinery Not Protected............... 10 29 24 10. No Control Over Visitors....................... 12 19 18 .11 No Watchmen or Guards.......................... ... 45 60 37 .12 Miscellaneous Hazards ............................ 15 26 20 33 61 70 36 15 128 78 55 63 49 142 61 236 325 230 791 ; ] .i t ' : !V ; t fl -v U * * -*vM'AHiil ,;f i- vSg m ! V .` :* . i.: * i. g S g : B-gt & B 8 - S :S S .a :0 - B B * ifr g * 8 5*,9 .fr8 5 !ffl3 .S 5 S r a :ff& a - B * iS .` Crt'jc ii* mm*? *?>.<** m l&f? 1 4"j f \::: in j'i . -f y ;*` .*4-, * :* i;i: -., ;?:1 r.** f X.s r4: * ./l? . ..; *:-; <f. ' r: ? *, t* Discussion cl Paper MR. LARSEN: I think Mr. Belser should certainly be commended on his paper and that you fellows should spend a lot of time in going over that paper, observing the hazards. Most of the hazards are of a me chanical or physical nature that are taken care of principally through management and things like that They are brought out by observation of safety engineers. In the last part of his paper he said that on rechecks, going back over on the re-inspections that a little better than eighty per cent of the pre vious hazards listed had been taken care of by the management. That showed definitely that management was in full accord with this inspection as put on by the MPSD of the Federal Bureau of Mines. Originally there were 7,500 recommendations, and boil ing them down in his paper he had over eighty hazards listed, and to discuss each hazard or even touch on each hazard would take a couple of weeks to do. MEMBER: Mr. Belser's paper mentions* aluminum dust hazard. Would you"enlarge a bit on that, Mr. Belser? MR. BELSER: On that I'm afraid I'm not very well qualified to speak because those were picked up in California by in spectors there and they bad. two or. three explosions. I personally made no Inspection at any plant MEMBER: The reason I asked, of course, is that the aluminum dust treatment we are using is probably the finest you can get, and we have absolutely no trouble with alumimtny MR. HARRINGTON: I can answer you. The answer to it is this: that there are defi nite hazards and plenty of them in plants processing aluminum, irrespective of any thing anybody can tell you about it We know that MEMBER: On that table, on the resume total of operations, would you be able to give us any information on whether or not the operations without safety departments had the greatest number of hazards? MR. BELSER: In most of the big com panies there were very few hazards in com parison with the smaller ones. The small properties have really had a lot of bad things. Some of the. big companies with good safety organizations have hazards, and they are aware of most of them and are trying to fix them up as fast as they can, and they are doing a very good job. There are a lot of things, for instanoyin a small mine you wouldn't think of recommending --mine rescue equipment with ten or fifteen people: It would be out . of the question. In a small mine you wouldn't thinkof a regu lar safety committee. You'd think of trying to make a superintendent--if the mine Is run sloppily -- a little' more conscious of those things, and that would be alL I be lieve that's dear. - MR. HARRINGTON: I might state one thing here in connection with the paper. He mentioned that loose ground was noted in several places. We find, in the Lake Su perior district over the last four years in our underground iron mines that loose ground has caused approximately twenty per cent of our lost time accidents, and it's caused 47.2% of the time lost through acci dents. Wherever you have loose and underground mining you have the hazards. I just thought I'd bring that one point out The hazards listed here, as I said, are more of a physical nature and meaning where management can tala care of them, and really they only hit about 25% or 30% of our accidents, but it's a big problem.' The paper was of extreme interest to me since I am originally from the West I've worked in some of those mines. I think we can get away from a lot of these hazards through job instruction training and training our men to install equipment safely in the first place and fol low up with safety inspection. 1^ there is no more discussion I'll turn the time back to the chairman. Pi Pc JjH p mM' ## #?*:. fi? Mining Section 377 Fundamental Causes of Accidents (Panel Discussion) Discussion Leader: J. H. Mulcahy, Supvr, Industrial Relations, Republic Steel Corp., Duluth, Minn. Participants: B. G. Best, Supvr. of Safety, Oliver Iron Mining Co., Duluth, Minn. Dsl JoHNsauDE, MJD, Mesaba Clinic, Hibhing, Minn. j C M.. Felumah, Safety Eng, ^Montreal Mining Co, Montreal, Wise. C E. Haceb, Range Safety Inspector, Pickands Mather & Co, Hibbihg, Minn. MR. MULCAHY: The first case that well discuss is that of an electrician's helper who was horned on both hands aad.snffered Sash barns of both eyes, doe to. the short* tiremting of the contacts made an oil switch. He had worked as an dedtidaa's helper at die mine for a year prior to die date of the injury and had previous experience with other employers. At the time of the accident he was inspecting contacts on a live circuitbreaker. He inserted a combination plier- wrench onto the contacts and a flash re salted, spreading hot ml over his face and hands. The oil tiremt-breaker was one of several in the plant. Investigation brought out the fact that a few days prior.to the date of the accident the chief dectrician had given instructions to die electrical crew at the mine, governing several jobs. One job covered by Ins instructions was tire inspec tion and repair of oil errant-breakers. It developed that there was a lade of definite understanding of the instructions. The in jured helper said he thought they were given to the electrical crew generally. The chief dectrician said that he had intended spe cific jobs and specific instructions for indi vidual members of the crew and certain jobs were to be done by tire electrician and the others by the helper. The hdper had been doing other jobs around the plant and, ap parently, having finished them, he turned to the inspection of the oil switch. I am going to ask Mr. Hager to give us bus impression of the fundamental wrong in tins case. MR. HAGER: Mr. Mnlcahy, to get this discussion started I could say that this man was just a plain damn' fool, took his life ini his lands, and acted very unwisely. Before proceeding I'd like to bear from some of the folks out in the audience to find out what they have to say about this thing. MR. MULCAHY: I think there may very well be some discussion on this point in a crowd of tins size. I'm wondering, though, if you'd care to enlarge a little bit before we open it for general discussion, as to what is your opinion of the -fundamental wrong, either with the man's attitude or with Ms actions. MR. HAGER: My view of this accident, as far as I'm concerned, indicates that the chief dectrician had done a good job of in structing the men two days prior to,the date of the accident. That's the way it appeared to me after reading the rqmrt of the acci dent; reading the foremen's report as well as tiie investigation of the accident At the time, that this was going on there apparently were some job instructions and the only thing that I can see that the foreman didn't do property was to have the instructions that he gave the individual men repeated. .MR. MULCAHY: You mean spoken bade to him? MR. HAGER: Yes, At that time there were job instructions at tins particular prop erty, at the time the accident occurred, tiie program was well tinder way. I also found that this particular plant lad taken great pains to give instructions in respect to the locking out of switches when^men worked on circuits. This information was posted at every panel, posted on the individual switches; lodes were provided, keys were there MR. MULCAHY: A violation of a defi nite safety rule was involved in this case, too. * MR. HAGER: It is my opinion that there was a very definite violation of company ratings. Again going lock over the record there appears to be some argument, vsome difference of thought as to whether seme responsibility shouldn't have been placed on the foreman, and that's where I suggested that we might have some discussion from the floor. 378 33rd National Safety Congress, 1944 MR. MULCAHY: I think probably MR. MULCAHY: I think I can agree we're in better shape for a little discussion with what you have said. I wonder if any from the Boor on that point than we were a one else on the panel has anything to add to little earlier. Instruction sticks out in this this one. case--at least it impresses me that way, that the case should be covered by definite in structions. A method was chosen to instruct; whether or not the method was proper is questionable. Whether the instruction should have been repeated is questionable. Fm won dering, in view of the fact that instructions were given and apparently misunderstood, if someone would 13m to express an opinion as to what responsibility a foreman does There's another question that occurs to me but I'd like to have an expression from any other panel member before we turn to it MEMBER: What about this man's imme diate foreman? Who told the electrician's helper to do the job ? Or did somebody else? MR. MULCAHY: The only thing I can say in answer to that is that this man had been doing some jobs for several days have for the safety of his men. around the plant and apparently assumed MEMBER: Mr. Chairman, to me it just appears we're not well enough informed as to what the instructions were that were given the man. Consequently we can't form an opinion of him, as to just why he did this. It does appear that, there was a misunder standing,. but as far as a foreman's respon sibility is concerned regarding what his man does, I think it's all the foreman's respon sibility. The responsibility falls on the fore man if he doesn't give the instructions ex plicitly enough to know that a subordinate is going to do the job right I know from personal experience it doesn't make any dif ference whether you have a new man or a man on the job for years, it just-seems in voluntarily to creep out of you to say "Be careful that the power is off; see that the disconnects are pulled after die oil switch is open." that, after these instructions were given, this was just a continuing job for anybody in die crew. He went on his own, so far as that's concerned; there was a misunderstanding, as long as he was not definitely dear, although he said he was very .dear. There was no question but that insofar as he was con cerned the instructions were general and anyone in the crew amid take these jobs as he bad an opportunity to do it. In other words, it was one of the things that had to be done around the plant and anybody could do it as he got time. MR- HAGER: I can't subscribe to that thought after reading that aeddent report It impressed me that this man was well in structed that the three men on the crew were very, very definitely instructed as to the duties. The man involved here; in going back over the record, was to take up motor MR. MULCAHY: I think we can agree that the instructions, so far as covering the job is concerned, were complete as to the job. Where the difference of opinion arose in the investigation of this accident was whether the instructions were given to the electricians to do this particular job or whether they were bread enough that the helper might have understood that be was screws to do other work, and didn't have anything to do with the oil switch job, changing the contact; that was very defi nitely the job of the plant electrician and as I said before, I think the only mistake that the foreman made there was in not hav ing the man himself or the men in that three-man crew repeat the instructions. MR. MULCAHY: Then you seem to to go ahead and do it, too. There was noth ing wrong with the instructions as instruc tions. The error crept in in the difference indicate that the responsibility was very light so far as the foreman was concerned and that the helper probably was trying to of opinion that did exist as to-whom the educate himself? instructions were given to. MR. HAGER: There should be an an MEMBER: I didn|t mean to infer that, in this particular aeddenj, the responsibility fell on this particular foreman. You might swer to that aeddent Tfce answer, as I see it, is that the man failed to comply with the company's rules and regulations of lock have gotten me wrong. What I maintain is ing out that switch. generally that when you say "what respon MR. MULCAHY: That leads to the sibility falls on the foreman?" that's what a question I said I still had in mind `on tiffs foreman is for, to assume the responsibility. one. Every once in a while you will find n agree >tl curs to <a from mtoit ; immcxidan's ly else? ETI can an had il days ssumed en, this yin the s that's ling, as though was no n an* I see with lock* Mining Section 379 some electrician or some mechanic who knows better, failing to lock out moving machinery or electrical switches before he works on it. There may be somebody here, either an electrician or a mechanic or some one in that general line'of work who can give us a pretty good slant an why men do that Why do they take that chance? Is there anybody who would like to answer that question? MEMBER: Mr. Mulcahey, I think if we could answer' that we'd have the acrident situation licked MR. MULCAHY: Well, we can do it We've had a good meeting. MEMBER: It seems to me this particular fellow was going farther than his instruc tions. Very likely he went beyond the in structions for his particular work and in so doing encountered this acrident to himself. If he is that type of fellow and he hasn't teamed a lesson by it--he'd better change bis profession, bemuse electricity is some thing that you want to know what you're doing before you start. I think in this case it was definitely the man's fault I think he was probably a little overambitious or overenthusiastic and started something which he didn't know the ins and outs of. MEMBER: Mr. Chairman, I wonder if the foreman knew this man and the man knew the foreman. It would seem to me this man was in the electrical game, was supposed to have certain knowledge of electricity which he probably didn't have, and it would seem to me that it would have been the fore man's business to know just, exactly if that man knew what he was to do and if he should have drawn that out by having him repeat the instructions. Sometimes there is such a_thing as overinstruction. You take a man. who is thor oughly experienced and you know he is, and you don't tell him the details of his job; but if the foreman didn't know the capacities of this'worker then I think the foreman defi nitely was at fault .in not finding out ex actly whether the man understood what his instructions weie. MEMBER: I'd like to ask one question. If there was a standing order that no hot work should be done, if the fonanan ob served his men from time to time to see that tiusy were obeying that rule? Is this an iso lated case of a man working on hot wires? MR. HAGER: That's a very general rule in the plant, that nobody is to work on any hot wires or hot circuit MEMBER: Did the foreman see that the rule was obeyed or did he neglect it and thereby create a habit in tbe mind of the helper, which caught him on this particular occasion? MR. MULCAHY: Of coarse I suppose you will never establish whether these things are habit or whether they're not My ex perience has been that the accident that caused the injury is' the first one of its kind that ever took place, regardless of where it happened. We never had that happen before. That's always the answer. I think that we can probably agree that we've discussed tins thing from the two sides that should be dis cussed--whether the blame is entirely on the part of tbe individual hurt, which is an oldfashioned idea, I think, or whether it is en tirely on the forces of supervision or whether it might be divided and it appears to me that in this case there was probably' some division of responsibility, sane divi sion of blame. Instructions were given. The pant comes up, were the instructions under stood, and in the final analysis it's a question, of education, education properly given, in struction properly understood and a definite regard fo? safety rules. If those things are done we've at least gone part way in whip ping some of the fundamental causes of acci dents. If there's no further discussion on that we've got another one that's interesting, too, probably a little bit from the same angle. This one is where there was a new level being opened in an underground mine. The ore body was wet, so that the temporary fuse and cap magazine had not been moved from its original location near the shaft and this was about 3,000 feet from the working places. Capped fuses were placedJn carry ing cans, each holding 50 to 75 fuses, and were carried by the miners to a convenient location in the working area where the cans were used for storage. A gang of three miners driving a crosscut loaded 19 holes, each provided with a sevenfoot fuse. Two of the miners started light ing the fuses. The men working'at the right side could not light one fuse. The third man in the crew, who had been standing nearby, stepped forward, cut off the end of the fuse and then split the new end. By this time the ' ':W m m u7,11; s *1 tpi Ai .^ ,33rd National Safety Congress 1944 first man's fuse lights had burned out, and well, I could say that the chances of this he used his carbide light to light the re accident happening would have been very maining fuses on his side of the cut He much lessened. then helped his partner whose light had also burned out They were lighting the fuse in the lower left-band, corner when one of the upper boles exploded. The men ran to safety. Two of them escaped injury, but the third, who had been struck by flying chunks from the first explosion, sustained injuries in the chest and legs. * MR. BEST: You might call this a beau tiful accident There was only one man hurt when three might have been killed. The one man that was injured lost some 280 days. Now, these fuse cans that carried from SO to 75 fuses were not individual contract cans. They were cans that were carried in to be used by all the miners or any of the miners in that particular ana. Another thing to be brought out is that the fuse lighters were also used as timers, and there was a A second cause was the damp fuses. If the fuses hadn't been damp, of course, they wouldn't have had any trouble lighting them. If the fuse station had been moved closer to the working places it's probable that the men wouldn't have carried in such fuses or possibly would have gone to the fuse sta tion to. get them when needed. The fuse would have been issued in smaller Incidentally, this accident happened several years ago, before the well-known Federal Explosives Act went into effect. Since the accident, the corrective action taken was the buildiiig of a fuse house closer to the work ing places, the installation in that fuse sta tion of a drying apparatus for fuse dm had become damp, and the issuing of fuse in smaller amounts, the amount necessary for each 4ay, and individual contract cans. standing safety rule that as soon as the first fuse lighter burned out the men wen sup posed to leave the place. In reviewing this One might reasonably ask "why did not the supervisory force anticipate their condi tion?? Here you had a fuse station loafed it seems the direct cause, that is, the un safe act that actually caused the accident, jras the violation of this safety rule requir ing the men to leave when the fuse lighter binned out. There an several fundamental causes, to my mind, that caused the unsafe act In other words, why did these miners violate the rules? It wasn't ignorance of the rule. It wasn't ignorance of the danger. It was a desire to take a chance and not spoil their blast ,, at considerable distance from the working places. You were carrying in fuses in gen erous amounts, leaving them there for a day, possibly two days. Should your super visory force have anticipated that these fuses would have become damp and had they inspected them at different times to see what the condition of the fuses was? I don't want to say aye, yes or no on that, except that possibly a little more intensive training of foremen might have taken cate of this angle. To correct that you have the matter of penalties. * These men wen all penalized; even the fellow that was hurt was penalized when he came back, but perhaps more im portant than that is the matter of super vision. This happened once, where the fel lows got caught; God knows how many times it happened when they didn't .get caught It would seem that the shift bosses, the local foremen, possibly didn't know what was going on in the working places. In one MR. MULCAHY: I think that the in struction angle of the mining industry is a very poor one. I think instruction to the foremen as well as supervision and through the foremen to the workmen is extremely important. This accident imficates to some extent at least that there wasn't a great deal of difference in the type of thinking; type of action that was peculiar to the miners, the man who was hurt, and that of supervision. It seems to me they were both willing to mine that I know of the foreman-issued the take a .chance and probably as long as we're powder for every blast They know condi willing to take chances we're going to run tions before the blast, and'they issue the proper amount of explosives, and also twice each week they had to inspect the blasting operations in some contract and make a re port on it I don't think that that method across these accidents and as we get them we're going to throw together an investi gating committee which probably, nine times out of ten, will not be composed of any better brains or any different brains than we was handled in this particular mine. If the had on the job regularly day by day. and method described had been used I doubt-- that investigating committee is very likely 8 j< St w it 11 tl f< si tl cl di in tl in n tr b to w to 0 w at ID W .11 1 le C! in m lil w bt a til til tii m ft m f this \ ! s. IX . they them, ser to it the les or i sta- fuse Bunts, sveral Jderal * the is the vork: sta- that' ise in f for d not Ondicafed ridng gen* :or a uperthese they what lg o! ogle, e in* Is a i the ough taefy sont deal *of , the stoa g to ve'ie ran Stem tsti- any j we and kriy Mining Section 381 going to find some better way of doing the THE CHAIRMAN: Was it very wet? job and a safer way of doing the job. The point that I would like to make is that it seems sad, to say the least, that we have to -wait until someone is hurt, before we put into effect better methods and' safer methods. If somebody disagrees -with that I'm not thin-skinned at all. I have a pretty strong feeling that a great responsibility rests with supervision and after all supervision is in the saddle as far as making necessary changes in mining operations. I'm perfectly willing to listen to any different opinions on that score, however. MEMBER: Were the mm who were do ing die-blasting working contract, and were the foremen who supervised die job dar ing in the production if a amain thing was reached? MR. BEST: It was damp. THE CHAIRMAN: Just ordinarily? MR. BEST: Yes. THE CHAIRMAN: We had something like that ourselves. Our two mm got killed, however. We weren't quite as fortunate as you were. After the thing was all over we shovded out this drift rock and we found where they had trimmed the fuses twice-- took their first trimming on dght inches and cm the second trim, because they were get ting dose to quitting rime, they trimmed it down again. They were contractors, too. I had pieces of fuse 21 indies long. MR. BEST: I think this third man cut off a couple of feet instead of mcfaes. MEMBER: How about electric blasting MR. BEST: The nun were working con and getting rid of the fuse? tact^ but die foremen were on a daily-wage MR. BEST: These fdlows were more basis. proficient in cap-and-fuse blasting than they MEMBER: I can understand why the were in electric blasting. That's something mm failed, but it would seem to me these to be considered. would be some system of checking the light THE CHAIRMAN: Another thing we ing as far as die issuing of die lighters was found in our case. We use carbide lamps concerned. You run into that right along. for all of our lighting fuses but they are Our neighbors had an accident where they supposed to use a safety fuse. In other weren't sure how many lighters were lit; words, if they're using a seven-foot fuse, and I can see why mm in their effort to * they cut it in half and light that. When the make more money are going to take dances - detonator goes off they're supposed to go when'it comes to blasting a place where out. We found the carbide lamp in the mud- they're having a little trouble with water. pile with the carbide in and no water, but I don't know what can be done about it un they bad used the Spitz fuse. You all know less you can supervise the number of light what that is; take a piece of fuse and notch ers that are used in a place. We use a nine- it Instead of notching it dose they bad inch lighter. We instruct our mm if. one notches further apart and that's where they man can do the lighting with one nine-inch * lost their time. lighter, okay; if be can't do die lighting MR. MULCAHY: Doesn't all this indi with one nine-inch lighter then there must cate that they're still taking dances and a be two then with lighters, both ligfatingisi-. lot of education should be dose? It's the mdtaneously, and when the lighter goes ant only way you're going to clip it die men go oat with it, but Tm not saying THE CHAIRMAN: In order to settle it that that's going to solve the problem.. all, regardless of new mm or old men, we MR. BEST: Those are the same instruc went to dectric blasting in all of our drifts; tions these men had. almost everything is dectric blasting now. THE CHAIRMAN: How many boles That taught us a lesson. were they fighting? . MEMBER: We had an accident almost MR. MULCAHY: I think there were ninetern boles. THE CHAIRMAN: And a seven-foot fuse, and die fuse had been stored in the mine for a period? identical to that We; too; weren't quite as fortunate. One man was killed, and one wasn't In checking up on that accident we found a great deal of carelessness on the part of the men. I think that a great deal was due in that aeddent to the fact that we MR. BEST: A couple of days. had two men notknowing what the burning 38Z 33rd National Safety Congress, 1944 rate of fuse was. We have told them fuse foot I'll tell you another thing that's com bums between 30 and 40 seconds a foot ing in now. We're getting a few men back In checking up afterwards I found that in from the Army. I don't know about the every mine there was at least one man, and Army. When we get these fellows back sometimes more--old time miners that bad from the Army Engineers and ask them been working frdfo 15 to 25 years in a mine drat question they say "A minute to the --that had the idea that a fuse burned at the foot; that's what the Army tells us." I rate of a foot a minute; one fellow even don't know what you're going to do with said it burned a foot in a minute and a half. those engineers bade in your mines with 40- I think that was one thing that really caused second fuse. our accidents. The fellow that was killed in that particular case had been working in our main drifts for over 15 years, continuous work in main drifts. That just shows that experience isn't always the thing. I think experience quite often leads to carelessness. MEMBER: Mr. Chairman, I don't think that we should be so concerned about the time of fuse burning ary more. I don't think that had anything to do with that acci dent The thing that was basically wrong there possibly was the fact that there was Just a short while bade I happened to cone no follow-up. into a drift and see same fellows making up explosives, and here was a' man fixing his primer cartridge and doing everything right, except that while he was fixing it he had a dgaret burning in his mouth. That, to me, showed that carelessness was very prevalent among our old-time miners. I can relate experiences along that line. We all talk about supervision, more super vision, which is absolutely right, and follow up on the training; I have told men, the same as any other safety man has told them, how fast fuse burns, and 1 also told them that when that lighter burns out, you get Just to get around and give these old- out * If you can't light all of it with one time miners a knowledge of actual burning lighter, two lighters should befit at the rate of fuse we took ten-foot lengths of same time; and when they go out, yon get fuse and with a couple of stop-watches and out After a yen' one gang, because they several of their own men running the stop were missed in the checkup, were asked how watches we timed the burning rate of fuse. they lit their round. They answered "When I think now all of our men know that fuse one lighter bums halfway down and we have bums faster than one minute a foot I think a lot of holes we light another one." Right some of you might check and find about the there it proves that had the thing been fol same situation that we found. lowed up religiously and often enough we MR. BEST: I'd like to bear out every thing that was just said. One standard ques tion that. I ask every new employee coining into the mine is how fast does fuse burn. probably would have gotten rid of that fight ing the second lighter when the first one burned half way. Fortunately we didn't get into an accident but it shows we could have. Since I started asking that question there Now, the time element is there. It's been have been over a thousand men faired. I've figured out by somebody else and put on the got four answers that were right market, given to the man to use and it's our MEMBER: What do they say? job to make him use it and use it properly., MR. BEST: The 996 plus told me fuse burned erne minute to a foot, and in our country it bums 40 seconds to a foot. There's the answer we're getting day after "day. I MR. MULCAHY: I think the discus sion seems to boil itself down to either no education or not enough education or no follow up of the education. drink a lot of trouble comes in blasting acci MEMBER: There's one tiling that we're dents from that fact I got hold of the pow losing sight of, and I don't think it's been der up in Canada Industries, Ltd. They brought out already. I don't think there's a didn't know what was occurring and had no man in this room that can take a piece of idea that the condition existed. This sum seven-foot fuse and fight it and tell you mer they have surveyed the situation just when that fuse is going to go through, even as I have done and right now they're driv if he knows the exact burning time per foot ing that home in every way they can. The per minute. I don't think there's anybody fuse that they make bums 40 seconds to the here capable of judging time that way. If light- Mining Section 383 yon sit down in a movie five minutes is no time at all; if you're waiting for your wife to get ready to go to that meeting, five minutes is half an hour. There's nobody who can do that Men say, "I judge the time." There's nobody who can judge time unless he has a watch or time device; and that's the thing we have, to impress on these men--you can't judge the time! We give you a nine-inch lighter or a sixinch lighter and the rule is when that bums out you go out That's the thing we have to insist upon. You have to set up a standard of time and after that has elapsed, those men have to leave the place. MR- MULCAHY: Isn't the rest of the answer that when these fellows have worked with powder or anything else for years, they naturally prove the old saying that famili arity breeds contempt and that's the thing you. have to recognize andguard against THE CHAIRMAN :What alibi did the men have? Fast fuse? MR. BEST: No, I don't think the men had stay alibi except to say they took a chance. I know these three fellows, THE CHAIRMAN: That's usually the alibi; "I had a fast fuse." Out of every carload of fuse we get we take so many rolls out of each box--one every carload-- and we cut that in three-, six-, eight-, and twelve-foot lengths and we time that fuse-- the burning speed of that fuse. We take the average of that, make a note of it and put it in each one of our magazines. I've seen that fuse go from 38 seconds a foot tip as high as 52 on the same carload of fuse and same conditions. MR. BEST: We test our fuse the same way, and this fuse that we left in the can was tested following the accident and burned at the regular rate after we cut off an inch and a half; and .the timers burned at the regular rate In some other mines with con tract box cans there's a sign "The fuse you use bums at therate of 4ft1 seconds a foot" MR. MULCAHY: We have another accident. To show we don't pith all the.serious ones we picked some that resulted in less serious disability, but just to indicate what might happen to such things we throw diem in once in a -while Two-miners were moving a scraper past a timber- air hoist on a sub-level. As one of the men stooped over to remove a cable from under the scraper the air hose con nection on the hoist gave way. The hose lashed out and the coupling attached to the end of it struck the man in the face. Investigation showed that the air hose serving the hoist was also used for other purposes from time to time and that when it was rushed to the hoist after one of its other uses care had not been exercised in tightening the connections. This is an example of an accident and injury resulting to one workman through the negligence of another. In all probability the accident would not have happened if the one who had last used the air hose had con nected it securely when he lashed it to the hoist Mr. Fellman, I wonder if you will develop this a little fait * MR. FELLMAN: This is a fairly simple accident to analyze. There are three funda mental causes, all related. First of all, of course, is the one of su pervision. This air hose had been used for other purposes. The miners had taken it off of that air tugger when they were short of hose. They'd use it and return it That obviously is poor supervision, to allow a thing like that to go on. - Secondly, the carelessness of the work man who put the hose hack and didn't see that that coupling was tight That's obvi ously negligence on the part of another workman. Thirdly, the fact that there was no safety chain on that hose. - In other words, we come around to the third cause, the failure to provide the guard. If the guard had been there very .likely the hose would not have lashed out fax enough to have strode this man. So here we have an accident which seems to me is a combination of just about every thing that we've been talking about and should not do. Supervision Baled, careless ness on the part of the workmen, the guard was not in place; that's all I. have to say. MR. MULCAHY: We have tried for about 45 minutes here to get down to what we call the fundamental causes of accidents, and as I started out to say the only way we could hit on what might give some idea of what they are was to take individual cases. i A .* ImjJ/ ....... vi :i * 3? -=r 'W?>ft - .V';itV !l 384 33rd National Safety Congress, 1944 We're all concerned with preventing acci dents, but we're all having accidents, and we're all providing the doctors with more work than they'd like to have jost at this particular time. I'm going to ask Dr. Johnsrude to dis cuss, from his experience in the Mesabi Clinic, some of the things that might and should be done in the way of first aid cases, to ran the gamut of these things and give a pretty good overall picture of some of the things that are done that shouldn't be done, and some of the things that should he done that are sometimes forgotten in the way of first aid; just his*general impression of what laymen, which we all are, can do to aid the fellow who is unfortunate enough to get himself hurt on the job. DR. JOHNSRUDE: I think most first aid consists of overtreatment That is, the fellow workers tend to try to do too much to help or alleviate, the pain of the injiired worker. First aid consists of leaving the patient or the individual alone and getting adequate medical help 6r care. The first case we will discuss will be that of a bum. Now, bums may either be very severe, involving a large part of the body surface, or they may be relatively minor and involve only a small part of the body sur face. Regardless of whether they're severe or minor, the best first aid that can bevendered is to see that the individual gets medi cal care. If it's a severe burn, the best care you can give him in the meantime is to leave him alone, keep him warm, and keep him comfortable. People that die quickly of bums die from shock. The treatment there would be simply treatment of shock. Don't try to treat the bum itself. Don't try to apply ointment If the bum is very extensive and it's cold you can put on a simple*- dry, sterile dressing. The treatment the physician will use will vary and frequently the vari ous greases will interfere with his treatment of the burn, so the best treatment of bums is to keep the patient quiet and see that he gets medical aid as soon as possible. That also holds pretty well for first aid treatment of other conditions, as for in stance injury to a leg or arm. If there is considerable pain in the extremity and it appears fairly obvious that there is a frac ture, there is a case where you can do little more than simply leave the patient alcne and attempt to splint it I won't go into detail Splint it either by tying the extremity to something solid, like a board, or use special splints for that purpose. I think I should say that there are a few other things one should do in first aid. That is, determine whether or not a man is bleeding badly. Qf course, if an individ ual is bleeding you have to stop it if you want him to stay alive. The best way, I think, is simply a tight pressure bandage on the bleeding aria. They teach the use of tourniquets in first aid classes, stopping of arterial Weeding, but I have never yet seen a tourniquet applied -correctly. I be lieve the best treatment is simply a tight pressure bandage over the bleeding itself. If necessary hold it with your hands be cause you can always get aid within fifteen minutes. You should see that the injured man is breathing. If he's not breathing you must start artificial respiration. - To sum it up,.I would say that first rid should consist first of .all of stopping any hemorrhage, keeping your patient breath ing, or starting breathing if he's not do ing so, and leaving him alone. Keep him warm, comfortably and wait for medical care. THE CHAIRMAN: We train our em ployees in first aid and the fact of the matter it that I've''seen lots of tourniquets applied correctly. I've had cases in our mine where we couldn't stop It with a tour niquet; the man was holding the pressure point and the doctor came out and couldn't stop the bleeding. I don't believe that they don't know how to pot on a tourniquet. I'll say for our men they do, and we en courage them to -do all first aid. I've seen a lot underdone bnt not overdone. MR.' MULCAHY: I think there aright be something in this underground operation that yon don't encounter in an open pit operation, where more than keeping a man at rest is indicated. I think there that the Bureau of Mines is doing a fine job in their instructions and that by and large the rescue crews and.so forth.are fairly com petent in the handling of men. . MEMBER: I was rather surprised to hear your remarks. Thirty years ago the meditol profession objected very strenu ously to first aid in mmeopeiation. I don't t few aid. man livid- Mtning Section 385 believe that the standard of first aid is as high as it should be. I may be incorrect but I don't believe you have run into the type of first aid work that you should have ran into. Our doctors swear by it I don't know whether you're acquainted with Dr. Ilsingil, the orthopedic specialist or not He was called into a case where a man had a fractured tibia just below the knee joint The knee joint was involved. Two of the arteries were severed. Dr. Ilsingil. made this examination of the, limb and saw bis X-rays. He was surprised that it was possible to bring a man out of an underground mine and get him into the hospital without that third artery being severed, and he wanted to know from our local doctor how that cpuld be. You see, we have to cany them down through ladderwajrs and things of that sort We have to give thrman first aid in the work* ing place. We have to control bleeding. We have to apply splints and then we have to put him on a stretcher that will protect him while we. take him down through these various openings and out and np from the mine into our hopsital. It takes sometimes as long as 45 minutes. I have known cases where they have had to dig men out where it's run longer, and first aid had to'be administered while they're partly confined. I appreciate your remarks, but here's old Dan Harrington--they've been hammering on this thing for years and I would hate to think our first aid was so poor that our doctors would have to" say "Just let the man alone." Take in your case of burn. What produces the shock in the case of' the burn? Isn't it the pain that the man is suffering? DR. JOHNSRIJDE: That's part of it; not all of it MEMBER: Then the nervous reaction and one thing and another, but it would seem to me a properly formulated bum treatment ought to relieve that pain, at least Maybe I'm misinformed there, but my understanding is that there are good ones and bad ones. *. DR. JOHNSRUDE: I think you have misunderstood me. I am not . condemning first aid treatment I did say that fractured extremities should be splinted, and I did my that you should see that they're breath* ing and see that any bleeding is stopped. MEMBER: Fd like to ask the doctor if there isn't a time element in there that makes first aid very important when the injured man can't get to a doctor right away. We are underground some places' over 2,000 feet and to bring a man out takes time. At other times we can get him out in a few minutes, and I've had a doctor say he would rather we didn't put on any iodine or mercurochrome if that is the case, but when it's a matter of time we should take care of Mm. He's seen too much over done first aid where a fellow could be gotten: to a doctor in fifteen or twenty minutes; and he was so painted up with iodine or mercurochrome that-the doctor could hardly tell what was wrong with him. MEMBER: Fd like to ask you a ques tion in connection with the first case that we had. I happen to know that foil, was administered there and the man was in the hospital fifteen minutes after the accident occurred. Should we have used foil? Foil and sterile bandages--he was burned pretty badly. DR. JOHtfSRtH>EvThe point is if you start with fo&*; physician will have to con tinue with it Wow, a physician may or may not want to lose tiijtt-particular type of treatment. If ne^wants to do something else he's going to have to do a pretty thorough scrubbing job to get rid of the foil. ' MR. BEST: I think it's possible, too, that our first aid and medical departments are too widely .separated. The medical de partment ought to have a whole lot to do with the type of first aid we teach and practice, so the two are working together. . That would prevent us from getting all mixed up if, when a man is burned, the doctor wants to use foil and somebody starts using something .rise. ....... DR. JOHNSRUDE: I think that's a good suggestion. Possibly from where I come these people get medical care soquickly that a lot of elaborate first aid* is not necessary. MR. MULCAHY:. I think that's why the men who represent underground opera tions here. Doctor, have taken exception to your remarks. By and large yoiir ex perience has been with open pits, where it's a relatively short space of time that's re quired to get a man to a doctor. There's another question that-I think is interesting in connection with all cases, and : it; SS! t !>$ $ I n: 386 33rd National Safety Congress, 1944 I believe the doctor can answer it: I have a notion that a man's mental attitude, about things not related to his job, has a bearing on his performance on the job and possibly can influence him either as a safe or unsafe workman. DR. JOHNSRUDE: I think definitely a man that's well, both physically and men tally, a man that isn't worrying about either finances or his family's health, is less of a hazard than a man who is worrying about a wife who may have TB or a little girl who he is not sure might have to have a dangerous operation or something of that sort; he can't keep his mind on his work like the man who has no particular worries at home. We've endeavored to give these families themselves the best of medical care as well as the worker. MR. MULCAHY: I think that what prompted me to ask that question was a statement that was made to me just the other day by another doctor. He said he could show records that he had kept over the past years indicating that in the weeks immediately prior to Christmas, or the weeks immediately after Christmas the greatest number of accidents occurred. He said that before Christmas they're wondering what kind of Christmas they're going to have and what Christmas present they want to buy, and after Christmas they wonder how they're going to pay the bills. From my own experience I can't say that we have had a greater frequency of acci dents prior to Christmas or after Christ mas; I haven't any such record as that. I think you wouldn't have it so much in the open pit operations, where your operations during the Christmas holidays are practi cally nil, but I think there might be some thing interesting to develop there from other parts of the industry'; underground mining may show something of that sort, and mills may show something of it MR. FELLMAN: It might be an inter esting investigation but that's an old, old story about the mental attitude of the man on the job. What have we ever done and what can we do about it, as far as his home conditions are concerned? MR. MULCAHY: I don't know what can be done about the actual home condi tions, but I think there is something Indi cated that should be done. We go back to the old theme song--instruction; educa tion. The foreman not only knowing- die job to be done but the men to do the job. I think the-foreman who can know every man and know as much about him as possi ble is a very valuable foreman, not only to the company but to the men. He may be able to place them in jobs that are more suited to their particular mental attitude at the time. It's a very tough proposition and I think everybody is beginning to realize, if they don't by now, that education of the workman is very definitely in the picture and is going to stay. MR. FELLMAN: I wasn't questioning that, but take the doctor's example of a man with a tubercular wife and a child who needs an operation. Most any of us would worry about that What can the company do in that case or in similar cases of which there are any number of varia tions of that same theme? DR JOHNSRUDE: I might add that in our setup the employee pays so much a month for complete medical care of him self and his family, so extra medical care is no added burden to him whether it touches himself or his family. MEMBER: I don't think they do it as much now as they did probably ten years ago. Some of the companies, however, still maintain home nursing, that is, the-industrial nurse, and I believe if you can get a girl that fully understands her responsibili ties she can do as much toward cutting down your accidents, I would say, as any one in your safety organization.