Document wq2VZdab8DZKepENmK41Z8rJB

' Some Aspects of Underground Environ mental Control By JOHN W. WARREN Chief Ventilation and Industrial Hygiene Eng., Anaconda Copper Mining Co., Bum, Mont. .The literature abounds with information the system and that resistance pressure losses pertaining to the many phases, of man's at van* as the square of the volume it can be mospheric environment. The information readily realized what an accomplishment was available lacks in specific procedures for the prosecuted and the economic outlay involved.. prevention and alleviation of .concentrations Actually the air flow was.doubled for a of undesirable atmospheric contaminants. power increase of approximately 70 per Control procedures for underground oper ations become complex and installations diffi cult due to the physical nature of the sur roundings. It may be of interest to those concerned 'to present some of the results of experience and ealperimenfation. - Much of the material will be a review. The management of the' Anaconda Copper Mining Company has. for many years di rected the efforts which have achieved con trol of the underground environment. cent. Normally the power- increase would have been 800 per cent. Smooth surfacing was installed in 20 air shafts to reduce the resistance pressure losses. Airways of high resistance were enlarged or paralleled and 23 new*, reversible and more efficient main surface fans were installed. With a skin to skin octagonal air raise of a diameter of inscribed circle 9'. Area -- 67 sq. ft. the friction factor = A 0.0000000018. In a vertical rectangular shaft smooth surfacing is treated and pegged .with hard-- The policy of the Aanaconda Company .wood dowel pins. in its control of an environmental hazard las always been to improve conditions by proper ventilation, wet methods and any other methods that have been tried and found practical, thus eliminating the use of encumbering gadgets such as masks, helmets and the like.. Respirators are used only occasionally and in very few* places. In a horizontal airway long treated smooth surfacing is also pegged. The Anacotfda Copper Alining Companv has always cooperated to the fullest extent with the United States tureau of mines, and the assistance from the bureau has been very helpful and construct! ve. Accordingly, in 1935 the bureau was extended an invita- The campaign on dust .control began , with lion ot make a survey of the existing con the adoption of wet. drillings in 1918.. Con ditions in the Butte mines. ' version of percussion drills then in use was complete by 1926. During a full normal operation in the Butte district an excess of 1.400 drills have been in service at one time. In 1936 . a survqv was made under-the supervision and direction of Dr. Carlton E. Brown, chemist. United States bureau of mines. The average dust concentration for One of the major undertakings, to improve the Butte mines was fouiwi to be approxi the underground, environment was. the pro mately 2.05. millions of paartiefts per cubic gram to increase- the airflow through the .foot. The survey results supported the find mines. The program was formulated by Mr. ings of surveys made by otir own engineers A. S. .Richardson, who has given much to in their investigations both before.and since ward making mine ventilation the science the bureau survey. The free silica content it is today. His coefficients, of frictional re will average about 16 per cent. sistance to airflow and technical papers have A very fruitful research. program was been of great assistance to the progress of mine ventilation. Mr. Richardson conceived and developed the most ingenious scheme for air conditioning in use today. - . . prosecuted with the cooperation of the U. S. bureau of mines. One of Che major accom plishments benefiting the industry as a whole was die investigation of the relation of dust Knowing that power requirements vary dissemination to water flow through rock as. the cube of the air volume passing through drills. Findings have been published as Re- .