Document RJ9JkeNBMRo92RZEj4KweVnok

n Mining Industry Timber and Concrete Drift Footage by Year Timbered Slushing Drift Timbered Haulage Drift Concrete Slushing Drift Concrete Haulage Drift Total .................. 1947 . 62? . 75 .0 .2,775 194* 742 125 2.149 31S 3^31 1949 692 0 L2D3 964 2479 u 479 21288 Slushing drift footage required is about three times that of haulage drifts. Timbered slushing drifts were drawn empty, leaving haulage drifts with con creted slushing drifts exclusively on follow ing dates: 550 Level--Alay, 1949 8. Cleaning of spillage in haulage drifts with air shards is made easier m the concrete drifts due to smooth sides and a higher clearance. 9. Concrete being a poor conductor of elec tricity, electric blasting has bom mad* safer. 600 Level--April, 1949 650 Level--January, 1950 700 Level--June, 19S0 From this it is seen that the real benefits of having practically no repair were not at tained until 1950, when footage increase was made with fewer men. i947 194* 1949 IW Average Daily Timbcrmen ...46.2 49.8 47.2 38.0 The following advantages and safety fea tures have become apparent as this work in concreting haulage and slushing drifts pro gresses: 1. The most obvious safety feature of the concrete drift is its- greater capacity to . protect men from falling debris. 2 Elimination of hazardous repair work. 3. Elimination of heavy lifting. 4. Less experienced timbcrmen arc required for both original placement and occa sional repairs to finger openings. 10. The trolley wine is always on the south side of the haulage drift. The walkway along the haulage drift and the manway ladders to the slushing drifts are kept on the north side. With timber sets the walkway side clearance was only 9 in at the posts. Although we had 19 m. of clearance between the posts, we hare had a few accidents of men being squeezed. In the concreted drifts, the walkway clearance is 18 in. Safety sta tions every 40 ft make an additional 2 ft. of room. 11. In the timbered slushing drift, miners would occasionally hang blasting fuse and place dynamite behind the timber, to be _ used later. Often this would be forgot ' ten. In one instance; firing of a finger blast set off dynamite in the blocking with considerable damage. This has been entirely eliminated in the concrete-lined drifts, fuse and dynamite being kept in proper storage boxes. 5. Development of haulage and slushing drifts can be carried out far in advance of work actually required, with no de terioration of the development workings. This can be especially advantageous dur ing shutdowns. 6. The driving of both slushing and haulage drifts with an arched section has per* mitted the drifts to stand unsupported until they can be lined with concrete. 7. The fire hazard from timber is elimi nated. Recently the slushing-drift hoist stations have beet concreted, eliminating the danger of fire through electrical hazards. Some necessary precautions arc required: 1. Use of respirators and goggles is re quired by men concreting, (However, only limestone; sand, and stone aggre gate arc used, eliminating silicosis haz ard.) 2. Some hazard results from forming-board nails,4 causing puncture wounds. This is practically eliminated if working places are cleaned daily. 3. Good communication is essential between blowers and forms. This is done by using independent voice-powcred phones. 4. Firm handholds were initailed in the Mining Without Wood in the Asbestos Industry roof of concrete slushing drifts between finger openings. Some hazard of rolling chunks in drifts having 35 per cent grade is evident In a timbered drift men could step out of the way by aid of holding timber. In concrete drifts handholds are essential. In conclusion, it is well not to compare construction work and concreting in a pro ducing mine In construction work, the placer or pump is usually set close to the forms. The placer can then be emptied in about 45 see.; 200 to 300 cu. yd. per shift is not unusual. With our long pipe lines. 100 cu. yd would be the maximum amount poured Three to four sets of forms are used. This allows daily pours to one or two sections, while moving and forming the other sets. Average weekly pours are 125 to 200 linear feet of tunnel, requiring l$-$ cu. yd per foot A monthly high of 1,125 cu. yd. was used for lining drifts and miscellaneous construction work. Mining Without Wood in the Asbestos Industry By WALTER E. MONTGOMERY Safety Director, Quebec Asbestos Mining Association, Montreal, P. Q., Canada Wood, for centuries, has been the most splinters, but even this method leaves much widely used commodity in almost all methods to be desired. of underground mining. Wood timber repre* You can readily understand the concern one of the major overhead charges in in eliminating wood from asbestos fibre due operating a mine. In many mines it repre to the diverse nature of the two products. sents the greatest single expense, which is One is mined especially for its fireproof double and treble that of any other single and heat insulating characteristics while commodity necessary for the safe operation wood is the exact opposite in every respect of a mine. In years gone by the RgsgKS_af JKPod in Many mines have their own timber limits various finished asbestos products was one and an entire woods crew whose sole occu of the most frequent causes of rejection. pation is supplying timber to the mine. The presence of wood splinters was also Wood is considered as a contaminant to the frequent cause of mechanical damage, due mainly to the delicate nature of some asbestos fibre. It is a foreign material and is extremely difficult, if not almost impos sible to separate by present general meth ods of milling. Wood when crushed and milled will fiberixe the same as asbestos. Doe to the fact that it goes through a dry processing equipment Wood occasionally would continue all through the manufactur ing process and only show up in the finished aadusL. mth. i Mid riiuigha-Mbcaiot wnffJttikrimnc.w<Lgttkm- wlv to mci- tioa a few. If the final inspectors caught milling process it wilt become covered by dust, and it, therefore, closely resembles opened fibre and only by manual picking them before they were shipped, they would, of course, be scrapped. But human frailties being what they arc, some products reached on slow moving belts or picking tables could % majority of it be removed. Of course, magnetic separators are used to remove the open market that contained as little wood as you would find in ooe toothpick. tramp Iron, but copper blasting wire and la the early years of the industry it was wood chips and splinters still have to be considered a necessary evil, something which hand picked. Wood is sometimes removed could not be prevented, or which oo one from certain grades of fibre by passing it thought was important to give it much over screens or through other equipment thought. They hod wood pickers in those that has very critical air currents or suction days, just like the coal mines had booy and hoods that separate some of the heavier slate pickers. In the oW <fays ax one mine 24 Mmmg Industry IS men were required to dean the loading (ace with an air hose to dislodge the twigs and splinters from between the rocks, which were then picked up by hand in bucket*. But the boys couldn't and didn't get it all Complaint* continued to plague the industry. In recent year* the industry ha* com* to the conclusion that the only logical way to keep wood out of the finished product was to remove it from the source. This necessitated a complete reversal of standard methods of mining. It meant a complete retraining of the technical staffs at each mine. The underground and open pit crew* had to be trained to handle steel in stead of wood. Even the purchasing depart ment and stores had to stock a new line *f equipment fust imagine the same problem in your own mine if the order came through that starting the first of next week it is forbid den to use wood in any form. Now don't get the idea that this problem was licked overnight I* wasn't In fact, we Iiave been working on it now for more than 20 years. Progress has been made. We have eliminated practically all major uses of wood, hut a few of the. smaller ones still (>ersist. One of the main problems today is indoctrinating new employees. It is difficult i* explain to a new man that he is forbidden to use wood in any form. When he is told tltal he is not even allowed to carry wood matches in his pocket he U amazed. When the campaign was started, some mines gave away lighter* and placed lighter fuel at advantageous spots around the prop erly. Today it would be difficult to find a wood match. One of the greatest sources of wood splinter* in the open pits was the railroad ties which became broken and splintered at the face by the shovel or in moving. These were easily converted to steel ties. How ever, in the early days standard railroad gauge ties to carry an 85 lb. rail were not available and had to be manufactured in the mine's own shop*. SIkjvcI and sledge hammer handle* are another source of wood that So far we have not been too successful in changing. A steel shov-el handle was tried some time ago, but it did not prove practical, due to the twist that would develop. A test will shortly be made of a shovel nude completely of alu minum. One mine, in an effort to control the shovel splinter situation, requires that all pieces be returned to the storeroom he. fore a new shovel is issued. Steam shovels were equipped with wooden cabs which had to be covered with sheet iron and all new shovels were ordered with steel cabs. Dynamite is usually transported around all mines in the original box. In the as bestos industry all dynamite and caps are opened in an opening house, the sawdust removed, and the contents placed in rub berized canvas bags to be carried to the face. A steel blasting pole has been developed for placing bombs on a hang-up in a grizzly draw point. These blasting pole* are made of sheet steel f x 8* and rolled into a 1* size pipe, telescoped at either end so they can be joined. Even loading sticks for putting dynamite into the holes were a source of wood that had to be eliminated. Experiments ranged from rubber covered wood to brass ami aluminum poles which were rubber tipped. Flexible plastic rod was tried, AH of these couldn't Stand the rough treatment and the search is still on. At the present time we are experimenting with a solid rubber hot which is flexible enough to be rolled into a 4 foot circle. This looks promising for it is now possible to load long diamond drill or sectional steel holes in a narrow drift without much difficulty. Stairways and ladderway* in the open prt and underground which were previously all wood are now made of sted. It is still per missible to use wood if the location is far enough removed from a working face, but the habit of using sted is so strong that the machine shop will automatically use sted unless a specific order is given to make the step* of wood. At one time every machine guard in all the nulls was made of wood. If a beh broke, splinters would fly and get into the final flow of the screen*. About IS you* ago the making of guards was taken away from the carpenters and turned over to the tin smiths who, of course; used sheet metal. In due course it finally became a trspousibility of the machine shop and welding depart- Ubtmg Without Wood m the Asbestos Industry 25 gjy. vtd they now make some of the finest guards I have had the pleasure | -/ ---------Loading dnttes underground are all made of sted plates, "I" and "H" beams. Plat forms arc made of sheet steel and angle iron interchange of visits by our technical staffs continues to this day. Doe to the nature of the rock structure in the asbestos field, it was found feasible to adopt the block cave system of mining This is a system where a block of ore is ringed with boundary caving drifts, then undercut or pipe band rails. drifts are driven through die bottom of the One of the greatest and most important block. Then the undercut drifts are drilled problems that has fallen upon the engineer with a series of sunburst boles which are ing staffs of the various mines is the con leaded with powder for the primary de version from wood to sted for timbering velopment blast Below the undercut is the underground. Now the asbestos industry is no different from any other mining industry what rock structure is discussed. Some of it is good ground that requires no timbering for hun dreds of feet of main haulage drift. Other tectiora. however, require a 100 per cent timbering job, and it is quite common to use fore-poling and spiling to go through caving ground. Occasionally in severe slickensided areas two breast boards are required to keep the face itself from caving. There grizzly or slasher drift When the un dercut is blasted, then the block starts to work down and is then polled through the grizzly raise, into a slasher drift or down through grizzly bars to the kaufizar level IOC below. Even though the grizzly drifts are cut into solid rode, with a 20 foot roof or bock, the pressure from the caving block is some times terrific and the steel timber in the grizzly cabins is subjected to pressure and force that no wood could ever stand. have been instances when a whole 8* x Ilf Ia making these grizzly cabins we have main heading round was pulled with 6 sticks progressed through a scries of stage* from of powder with considerable overbreak, and J* X's to 4* ITs and S' and 6* I*s and H*s then the driller would be reprimanded be and cable remfordng to where we now use cause he didn't load only the caps. heavy duty 8* H*s at 10* centers and in From that you can see (hat weak ground some cases they are solid. it encountered and that it not only exerts But as all things progress, we fed that it vertical pressure but side pressure as well. is a step forward now to endeavor to elim Consequently, some of the steel timber in inate sted wherever possible by the use of stalled in the early days couldn't take the concrete. It has been found that when re required load. There was no previous experience to go by. Trial and error were more the rule than the exception. One mine would pioneer one idea of timbering and install it in their own mine and let the bugs develop. By that time one of the nearby mines would then be ready for underground development. The experi ence of the other mine would then be used to advantage, improvements would be added and experience of the second mine would inforcing is used m concrete underground that it develops a fine of weakness and is subject to cracking. When oca- sted forms arc solidly concreted, vibration will stuff off the outer shell of concrete. Experiments were made by eliminating the reinforcing from concrete and a great im provement ia strength was found. If taking a little sted out on the grizzly level helped the concrete why not go farther and take it all out and make a solid monolithic struc be available for others. In this respect the ture of pressure poured concrete! asbestos industry has enjoyed extremely This is sow being done and it is too early I do*e cooperation with each other in solving their mutual problems. While the asbestos mines have nude sub stantial contributioas to the mining industry in advancing the technique of block cave system of mining, we in tors are deeply indebted to several Anyrican mines, who, 20 yean ago, gave us the benefit of their yet to evaluate our experience. Some of our early grizzly openings were too large, we were too optimistic, and they caved in beau tifully and dutifully. They are now being rebuilt and the growing pains we went through with steel we are duplicating in concrete. Maybe about two years from now we can present a paper on mining without experience so we could get started. The wood or sted.