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By Irving Hartmann, John Nagy, Donald Mitchell

"SUMMARY AND CONCLUSIONThe test data indicate that water infusion of the Pittsburgh coal seam does not reduce the amount of fine dust produced during mining operations to the extent reported elsewhere. Wide variations in the amounts of dust collected in the air current were noted in duplicate samples and repetitive tests. Changes in depth and location of the infusion holes and amount of water injected and addition of a wetting agent to the water had little effect on the amount of dust liberated.Water was forced readily into the coal. Some water flowed out along the cleats, but an appreciable amount remained in the seam. Little or no water pene¬trated the coal seam above the upper infusion holes.The average dust concentration (with and without infusion) in the return air, 40 feet outby the working face, was 25 million particles per cubic foot during undercutting, 20 million during drilling, 75 million during shot firing, and 20 million during hand loading. At the working face the average concentration was 3 to 6 times higher. The concentrations were measured at an airflow of 1,600 cubic feet per minute (c.f.m.) at the face.On the basis of this short investigation, no final conclusions can be made on the effectiveness of water infusion in reducing the amount of fine dust liberated during mining in the Pittsburgh coal seam. However, the data indicate that dust reduction resulting from infusion would be small.INTRODUCTIONThe production of fine coal dust is an inherent part of nearly every phase of mining. The use of large, high-speed continuous-mining machines and other mechanical equipment has increased dust production. In addition, in coal seams that have been subjected to high pressures for a long period, and particularly in dry and friable seams, some very fine dust is in the seam before mining. Much effort has been devoted to allaying and collecting at its source the fine coal dust released during mining. One of the comparatively recent techniques that has been developed for this purpose is infusion of water or other liquids into the coal seam. This method consists of injecting water under pressure into a coal seam to neutralize the fine dust released during mining. The water generally is introduced through bore holes in the face before undercutting."

Jul 1, 1957

By C. Van Dyke, K. Van Dyke, J. Gutierrez, C. Nowack

"Using propidium assay and flow cytometry, we examined how silica exerts its toxicity toward phagocytic cells employing the human neutrophil as a model. This toxicity appears to be associated with calcium bound to silica. Once the silica with calcium is phagocytized, the extra calcium causes the death of the cell. Using ""Ca we found that 6 to 10% of millimolar calcium is bound to milligram amounts of respirable-sized silica (diameter of 5 µ.m or less) at physiological pH. If the silica particles arc coated with an organosilanc (Prosil 28). calcium binding is decreased by 60% as is cell death. Pretreating with INDO IAM (a chelator of intracellular calcium) reduces the cellular death by 80%. Nonfibrogcnic particles- polystyrene beads or coal dust-produced 10% or less cell death in a 4-h period. Silica with no added, external calcium appears to exert toxicity to neutrophils; however, pretreating cells with EDT A decreases cellular death to the level of nonfibrogcnic particles. Chronic toxicity with silica-calcium appears similar to the chronic toxicity in gout where particles cause a cycle of inflammation. c 1993 Academic Press, Inc.Silicosis is an occupational disease caused by the inhalation of fine particles of silica, usually between 0.1 and 5 µ.m in diameter (1). A recent hypothesis explaining silica's toxicity suggested that surface free radicals caused damage to cells (2). This explanation appears doubtful, however, since the addition of silica to water, such as that found in biological systems, quenches free radicals; also, such a hypothesis does not provide basis for a persistent inflammatory pattern that lasts for years. Kane et al. (3) proposed that silica's toxicity resulted from an excessive concentration of calcium ions within the phagocytic cell (macrophages). However, the mechanism that was capable of linking silica to an excess of intracellular, ionic calcium was not explained. The surface of silica is certainly involved because covering the surface with polymers or phospholipids decreases silica's toxicity (4-6).When silica is engulfed by macrophages platelet activating factor and leukotrienes are produced (7, 8). This is the same inflammatory pattern produced by phagocytic cells exposed to the calcium ionophore A23187 and ionic calcium. How could silica be acting like A23187? Perhaps calcium binds to silica extracellulary and then is released intracellulary following phagocytosis; the latter process, in a sense a ""piggy back"" process, would permit activation of inflammation and cell death mechanisms."

Nov 1, 1995

By N. A. Eilertsen

The Aroostook manganese-bearing deposits lie within a rectangle 30 miles wide and 70 miles long. Over 40 different deposits have been discovered in this area, but they have not been mined because the ores are difficult to treat. In 1949, the Maple Mountain area was selected for detailed investigation by the Bureau of Mines, because study by the State of Maine and the Federal Geological Survey indicated that it was the most promising in Aroostook County for developing a large tonnage of reserves. Investigation by the Bureau of Mines disclosed that all of the reported deposits of the central district were located on the limbs of a syncline underlying a pear-shaped area of 283 acres between the crests of Maple Mountain and Hovey Mountain. The ore area has been outlined by trenching and drilling along three sides of the perimeter, while the remaining side is defined by a fault. The area has a length of 6,300 feet and a maximum width of 3,100 feet. Diamond-drill holes have intersected the deposit as deep as 1,550 feet below surface, but additional deep drilling would be required to determine the intensity of folding or warping at depth. The Maple Mountain-Hovey Mountain deposit lies in the slates of Ordovician age and is classified into three zones, of which the upper, averaging about 57 feet thick, is designated manganiferous purple and red slate. The central zone, also averaging about 57 feet thick and containing the highest manganese content, is manganiferous, banded hematite. The lower zone is manganiferous, interbedded hematitic and green slate with an average width of about 33 feet. Manganese minerals occur with hematite in all three units. Trenching on the northwestern slope of Hovey Mountain uncovered other disconnected deposits of manganiferous rocks of earlier age than the ore of the syncline. The general strike of these deposits, which range from 15 feet to 75 feet in thickness, is southwest a length of 5,000 feet. They dip steeply southeast. The ore of the syncline is predominantly deep, hematitic red, inclining to red-dish black, fine-grained, dense, and thinly laminated. It is hard and siliceous. Hematite has, in places, been altered to magnetite. Because of the fine-grained texture of the ore, the manganese-mineral constituents are difficult to determine. Of the manganese silicates present, braunite is the most readily identified. Manganese carbonates and oxides are found also.

Jan 1, 1952

By C. W. JEFFERS

During the past few years the use of mechanical equipment for the loading and transportation of coal at the working face has rapidly increased . Many mining officials are of the opinion that mechanical methods have tended to reduce the hazards of mining, and a number of statements have been made to this effect . Little actual data upon which to base conclusions in regard to the relative safety of various methods of mining have been made available . While it may be possible that these systems of mechanical mining are inherently less hazardous , obvious dangers should not be disregarded in the belief that the mere act of installing mechanical loading equipment automatically brings about better accident records . The same rules and regulations , modified to meet the new regime must be applied with the same discipline as heretofore . By diligent study and application there is reason to believe that new methods of concentrated mining can be utilized with at least a possibility of increased accident performance . With the idea of preventing accidents by taking available precautions against their occurrence , attention should be directed to the dangers that exist where room and face conveyors are in operation . Due to the cost pressure prevalent in the mining industry at the present time mechanical means are often used in an attempt to decrease cost of production. The management , after having spent considerable sums of money for new equipment , is expected by stockholders and investors to show results by increasing tonnage and reducing operating costs . Consequently the operating officials apply the same pressure to local mine officials to obtain results . The natural reaction of the superintendent and mine foreman is to secure the maximum production from the new method , and unfortunately safety is frequently , if not generally , sacrificed to this end . In many instances , operators of new types of mechanical loaders are difficult to secure and after being obtained are difficult to hold , especially if the new equipment is more or less in the experimental stage . The tendency is to handle the machine operators with " gloved hands " and to permit many unsafe practices which ordinarily would not be allowed, in order to keep from antagonizing them and losing their services . Although these unsafe practices become habitual and even uneconomical , conditions thus established are difficult , sometimes impossible , to change .

Jul 1, 1930

By C. W. Sill

[In the original Norris and Fay method for determining selenium, selenious acid is reduced by an excess of standard thicsulfate in accordance with the following reaction: H2Se03 + 4Na2S203 + 4HC1 = Na2SeS406 + Na2S406 + 4NaC1 + X20. (1) The excess thiosutfate is then back-titrated with standard iodine solution. The disadvantages of ouch a method are obvious. On an unknown sample, the quantity of thiosutfate required would be difficult to determine; a definite excess is required, but large back titrations would be undesirable. Inasmuch as thiosulfate is decomposed by acid, considerable error may be introduced in this method, the amount depending on the acidity, temperature, concentration of excess thiosulfate, duration of contact between thiosulfate and acid, and other factors, In a critical study of the Norris and Fay method, Coleman and McCrosky3/ show that the method is accurate to less than .1 part per thousand if the excess of this sulfate Is not greater than 5 ml. of 0.1 N solution (in 1.0 ml. of 0.x4 N sulfuric acid) whether the titration is made at 0° or 20°C. A greater excess produced unsatisfactory values at either temperature. Coleman and McCrosky regulated the excess thiosulfate by adding 5-ml. portions of thiosulfate solution followed by the addition of 1 to 3 drops of 2.5 percent potassium iodide in the presence of starch. If a starch-iodine blue color formed locally around the drops of potassium Iodide, the reduction of selenious acid was not complete. On stirring the solution, the local blue color fades and another 5-ml. portion of thiosulfate is added. When addition of potassium iodide fails to produce a local blue color, reduction of selenious acid is complete, and the excess thiosulfate is then back-titrated with standard Iodine solution. The number of equivalents involved in the reduction of selenious acid by either thiosulfate or iodide is the same, and therefore no correction need be made for the potassium iodide. This procedure is much better than the original Norris-Fay titration, but acidity and time would stilt be rather critical factors subject to variation with individual technique. Also, the method still requires the lose of two standard solutions, a rather undesirable factor from the standpoint of routine application.]

Jan 1, 1954

By A. W. Khair, L. D. Gehl

"This paper describes the study of bit wear characteristics on three types of rock namely Tennessee sandstone, Berea sandstone and Indiana limestone. High content of quartz with quartz cement in Tennessee sandstone causes removal of material from the bit body and dam2ge to the tip of the bit resulting into excessive weight and height loss as compared to other two types of rock. The drum speed and water spray pressure do not contribute significant effect on bit wear. The polycrystalline compact diamond (PCD) tipped bits are more wear resistant than the ordinary tungsten carbide (WC) tipped bits, but, due to wider body of PCD bits, the wear rate increases particularly at greater depth of cut. INTRODUCTIONThe impact of bit-rock interaction during the cutting process in underground coal mines has always attracted the-interests of mining operators, researchers and the manufacturers. Coal cutting bears directly on airborne coal dust generation which causes ""black lung"" in coal workers. On the other hand, rock cutting generates frictional sparks causing face ignitions. The bit wear not only produces airborne rcspirable coal dust , but also affects the productivity, safety and economy. Hun and Evans (J) concluded that the point attack bits have greater ignition potential than the conventional wedge shaped bits. The results of a study (2) suggested that after 7% of weight loss, the bit should be replaced. In a survey study (3), it was found that the bit consumption of bit had an effect on the productivity and utilization of the continuous miners. The mining industry is yet to receive a solution which could provide them with optimum operating parameters for coal cutting machines in underground C9al mines.The study was, therefore, taken up to determine wear characteristics as influenced by the rock propenies and varying operating parameters. For the purpose of this study, three types of rock, Tennessee sandstone, Berea sandstone and Indiana limestone were used. The machine operating parameters included (i) drum speed, (ii) water spray pressure and (iii) bit type. Besides studying the wear characteristics, the effects of these parameters on the required cutting force, specific energy consumption, acoustic emission generation and bit temperature rise were also studied. Also, the preliminary experiments were performed to compare the bit wear between PCD and WC tipped bits."

Dec 1, 1995

By X. Shi, N. S. Dala, V. Vallaythan

"Cellular damage induced by silica dust is known to be associated with increased fragility and destabilization or destruction of the cell membranes. The mechanism by which silica dust effects biological membranes is still unknown. Using the ESR spin-trap methodology, we find that hydroxyl radicals are generated in aqueous suspensions of freshly ground silica. The amount of the radicals generated depends on the extent of grinding and ""freshness"" of the dust. Using linoleic acid as a model lipid, we show that the silica dust causes lipid peroxidation via ·OH, 02-, or linoleic acid related radicals as intermediates. Catalase and superoxide dismutase inhibit the formation of these radicals. The results suggest that free radicals associated with freshly ground silica and the related lipid peroxidation of the memberanes may be the starting point of the silicotic processes.INTRODUCTIONDespite considerable-effort over the years, the mechanism by which the quartz particles exert their toxic action on cells and the process(es) by which these actions progress to fibrosis are still not fully understood (1,2). It is generally thought, nevertheless, that the interaction of the quartz particles with the cell membranes is the starting point of the silicotic process (3). We felt that the mechanism of the membrane damage by quartz might involve oxygenated free radicals because (a) a suspension of quartz particles in contact with alveolar macrophages has been reported.(4,5) to initiate an enhancement of lipid peroxidation, defined broadly as the ;oxidative deterioration of polyunsaturated components of lipids, and (b) hydroxyl (·OH) radicals are known to be capable of peroxidation by abstracting hydrogen atoms from cell-membrane lipids (6) and initiating lipid peroxidation in lysosomal membranes (7). Moreover it is known that exposure of cell membranes, fatty acids and unsaturated food oils to ionizing radiation, which generates ·OH. radicals, causes rapid peroxidation (6). Earlier studies o~ the aqueous chemistry of quartz suspensions have reported detection of HzOz (8), implicating the formation of ·OH radicals as transient species, but, we are not aware of any report of the detection of ·OH radicals in quartz suspensions and this provided the motivation for the present undertaking. Since it is known that, because of their high reactivity (hence short life time) in aqueous media, the ·OH radicals cannot be detected via electron spin resonance (ESR) directly (9,10), we have used ESR combined with the spin-trap methodology (9) for studying the •OH formation."

Jan 1, 1988

By R. H. Bedford

"The El Dorado copper mine is situated in the foothill copper-zinc belt of California, which traverses the western slope of the Sierra Nevada with unusual persistence from Butte County to Kern County, a distance of more than 300 miles. Although this area contains such important past producers as the Penn mine, Union, and others, a great part of the current production has been derived from smaller properties, which depend largely on premium metal prices for economical operation. The El Dorado mine is in the latter group, which constitutes an important source of metal in a national emergency.Exploration by the Bureau of Mines by means of eight diamond-drill holes Indicated narrow, intermittent lenses of copper ore along structures boo feet in length. The copper occurs in massive sulfides composed of chalcopyrite, pyrite, pyrrhotite, and minor quantities of bernite. The sulfides have evidently replaced tuffs, which are interbedded with the Mariposa slates and shales.H. A. Weiler and Hal T. Hall, owners of the El Dorado copper property, requested an examination by the Bureau during the latter part of 1914. In December of that year an engineer of the Bureau of Mines visited the mine and recommended the project work undertaken. The purpose was to aid the owners in bringing the property into production of copper and zinc, which at that time was critically essential to the war industries.Complete factual data obtained by the exploration are embodied in this report.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G, Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.Acknowledgment is made to A. O. Johnson, chief, Reno Division, Mining Branch, and Lowell B. Moon, chief, Mining Branch, for their aid and direction."

Jun 1, 1946

By H. B. Freaman, C. L. Colburn, C. M. Bouton

"The mine telephone has been perfected to such an extent that it is giving satisfaction in most mines were the wiring is well insulated. Very often the telephone cannot be depended upon on account of falls of rock, grounding due to worn insulation or extreme dampness. In the event of a disaster it frequently happens that the mine telephone system is put out of commission by the agency that causes the disaster, at the time when it is most urgently needed. On this account the mining industry is interested in any kind of telephone system that can be counted upon in an emergency. Many requests have been received by the Bureau of Mines to devise means of utilizing wireless methods for this purpose.The results of some preliminary experiments conducted by the writers at the Bureau of Mines experimental mine at Bruceton, Pennsylvania, in the ordinary sending and receiving of radio waves through earth strata are described below. The experiments were made in cooperation with the Westinghouse Electric end Manufacturing Co., which assigned to this work three of its radio engineers, C. A, Boddie, E. C. Douglas, and F. D. Fessler,The preliminary experiments consisted first in receiving signals from without the mine by means of a receiver located inside the mina, and second, both sending and receiving messages underground through the strata. It was found that with a receiving instrument set at a point 100 feet underground, signals from KDKA station, of the Westinghouse Electric and Manufacturing Co. East Pittsburgh, Pa., could be heard distinctly. Station KDKA is at a distance of about 18 miles from the experimental mine. About 50 feet from the receiving station used in this test was a 6-inch bore-hole from the surface, lined with iron pipe and containing electric light wires which extended therefrom through-out the mine. The presence of these wires evidently assisted greatly in the reception, for when the receiving set was carried to another point in the mine removed from wires and tracks the signals were barely audible through 50 feet of cover. The fact that signals were detected, however, even though faintly, is sufficient evidence of transmission through the ground to encourage further experimenting.In sending waves underground the Westinghouse 20-watt B.T. model T.F. transmitter was used in such a manner as to send out continuous waves of 200 to 300 meters length."

Oct 1, 1922

By Jeffery L. Kohler, Eric R. Bauer

Prolonged exposure to noise over a period of years generally causes permanent damage to the auditory nerve and/or its sensory components. This irreversible damage, known as noise-induced hearing loss (NIHL), is the most common occupational disease in the United States today. Workers suffering from NIHL have difficulty understanding human speech and hearing other workplace cues. Despite the use of regulations and efforts by government and industry to reduce NIHL, the problem today is as prevalent as it was more - than two decades ago. Recently, the Mine Safety and Health Administration (MSHA) promulgated a new regulation that is designed to reduce NIHL in the mining industry. One of the more significant provisions is the elimination of MSHA's past practice of giving "credit" for the use of personal hearing protection, thereby reestablishing the primacy of engineering and administrative controls. However, there is a knowledge gap that is impeding the development and implementation of engineering and administrative controls. Although significant data exist on the exposure to noise by occupational code, little is known about the noise sources that contribute the most to the worker's dose. This is problematic in a workplace with multiple noise sources and workers who travel among noise sources. Yet without this knowledge, it is difficult to focus control efforts in any practical manner. Thus, it is important to characterize noise sources sufficiently well so that the sources most hazardous to hearing are identified and those conditions of exposure that are most amenable to engineering controls are pinpointed as well. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) is conducting a cross-sectional survey of noise sources and worker noise exposures in the mining industry to address this deficiency. The initial effort, conducted at a coal preparation plant and results are described in this paper. Preliminary analyses indicate that the noise levels on all floors exceeds 90 dBA in most areas, and that levels as high as 115 dBA were recorded. In addition, the one worker whose responsibility is to monitor the equipment and "house clean" the plant is slightly overexposed, even though he spends only half the shift in the plant. General information on the hearing loss problem in mining, a review of hearing protection use and noise regulations in mining, and other background materials are also presented.

By D. Harrington, B. W. Dyer

"One of the products of the activities of the United States Chemical Warfare Service is a simple device and method for nearly instantaneous determination of small quantities of carbon monoxide in air. Since the war, this device has been diverted to commercial uses, and is now being marketed in connection with rapid determination of the comparatively small but dangerous quantities of CO, which may be found in garages, in sewers, about blast furnaces, etc. Also, it probably has a definite field of use in both coal and metal mines in connection with fires and explosions, as well as in confined places after firing of explosives) the latter applica-tion being of especial importance in metal mining.The device as marketed is readily portable, being small and light enough to carry in a coat pocket of medium size. In operation, a sample of the air mixture is drawn into a small rubber bulb, then forced through a small glass tube filled with certain chemicals upon which CO has the effect of changing the original color from gray or white to shades of green, the deepness of the green determining the percentage of CO in the air. A color scale is attached for purpose of comparison and determination of CO percentage. Only a few minutes are consumed in obtaining the result, all work being done on the ground.The exact effect of minute quantities (up to 1/10 of 1 percent) of CO on the human system is somewhat uncertain, and much research has been and is being done to obtain definite data on this point. It is, however, definitely known that in air containing more than 1/10 of 1 percent CO men doing hard work are quickly and seriously affected. As the gas is tasteless, colorless and odorless, methods of determining the presence of both small and large quantities have been of much importance. Technical Paper 11 of the U. S. Bureau of Mines gives much data as to effect of CO on mice and canaries. It was found that mice show very little distress until the CO content is about 0.20 percent, but quickly succumb when that percentage is exceeded; canaries are somewhat more susceptible; they quickly show distress in as little as 0.15 percent 00, and soon collapse when that percentage is exceeded."

Jan 1, 1921

By Launa G. Mallett, Barbara Fotta

This report examines the effects of mining height on injury rates in U.S. underground nonlongwall bituminous coal mines, controlling for both the employment size of the mine and the mining methods. Using the mine-level employment and injury data reported to the Mine Safely and Health Administration, mines were stratified by average coal seam height (<43 in, 43-60 in, and >60 in) and by the average number of employees working at the mine (<20 employees, 20-49 employees, 50-99 employees, and >99 employees). To reduce the confounding effects of mining method on injury rates, mines using longwall mining methods were identified and excluded from analysis. The employment data show that as the mine size increases, the proportion of hours worked in low seams decreases substantially. Additionally, miners injured in small, low- scam mines arc, on average, younger and less experienced than those injured in large high-seam mines. Nonfatal disabling and fatal injury rates were computed within each category of employment size and seam height for the major types of accidents (ground falls, powered haulage equipment, machinery, handling materials, slips and falls, and hand tools). Our findings suggest that, regardless of the employment size, as mining height increases, miners are at increasingly higher risk of injury from accidents due to slips or falls and accidents involving shuttle cars and falls of ground. As mining height decreases, miners are at higher risk 01 injury from accidents involving roof bolting machines, load-haul-dump types of powered haulage equipment, personnel carriers, and powered haulage conveyors. On the other hand, regardless of the height of the coal seam, miners working in large underground mines had higher rates of injuries resulting from accidents involving handling materials and nonpowered hand tools, but lower rates of injury from accidents involving continuous mining machines and lower rates of fatal injuries from falls of supported and unsupported mine roof. Finally, miners working at small mines in low or medium seams are at higher risk of being fatally injured by a ljll of unsupported mine roof. These findings suggest the importance of&apos; considering the working height of the mine, as well as the employment size of the mining operation, when developing intervention strategies to reduce injury risk to underground coal miners. Results also identify the need to further explore how mining height contributes to the frequency and severity of injuries.

Jan 11, 1997

By D. Harrington, B. W. Dyer

"Two recent occurrences in Western metal mines in each of which 3 men were killed due to breathing fumes from explosives, have aroused keen interest among mining men not only as to the exact cause of such accidents, but also as to possible preventive measures.In sinking the forty five degree incline Marsh *haft near Burke, Idaho, on May 13, 1920, a round of holes containing about sixty pounds of 40 per cent gelatin explosive was blasted by the night shift upon leaving at 11:30 P.M. It was customary for the night shift to leave compressed air blowers open at bottom of abaft until the compressor was shut down slightly before midnight. Presumably this was not done on the night of the lath as the fumes were so heavy in the shaft bottom on the morning of the 14th that at about 8 o'clock, Superintendent Bergen and one of the shaft men, on reaching the shaft bottom, were overcome and fell from the bucket into the sump containing about six feet of water; and when two other men went down in the bucket a few minutes later to investigate, one also fell into the sump and the other was barely able to roach the shaft collar. The three bodies were later on recovered from the sump.At 400 P.M., June 10, 1920, at the Dominion Mine, Colville, Washington, a round of 11 holes containing about fifteen pounds of 60 per cent nitro¬glycerine explosive was blasted in a fifty degree raise about fifty feet above the main tunnel level by the shift going off for the night. in this mine it was the practice not to try to blow out the fumes until just before the shift went to work the next morning, Although no work was being done on the night shift, one of the raise men, curious to ascertain the effect of the shots, about 7:45 P.M., wandered into the mine (which was a tunnel only a few hundred feet in length), and was missed by one of his companions about an hour later. When three men tried to remove the body of the inquisitive miner, two of them were also overcome; ultimately these two and the first man were removed from the point at which all were asphyxiated, which was practically at the foot of themaise."

Jul 1, 1920

By G. B. Fritts, A. C. Moschetti

"INTRODUCTION The act of Congress establishing the Bureau of Mines in 1910 delegated to the Bureau, as one of its principal duties and functions, the study of health and safety in the mineral industries with a view to devising and putting into operation means of conserving the health and safety of persons employed in the industries. One of the first health and safety activities of the Bureau of Mines was therefore organization of a trained force to promote instruction in first aid in the mineral industries. First-aid training has been an important activity of the Bureau of Mines since its establishment. The standard first-aid course requires a minimum of 15 hours of instruction and practice work. A person completing the initial training course is issued an engraved certificate and pocket card certificate; thereafter, only a pocket card certificate is issued for additional training.From 1910 to 1926 first aid was taught by trained Bureau of Mines employees; consequently, only a comparatively few persons were trained. In 1926, however, cooperative first-aid training was initiated, which provided the means to train the entire personnel of mines or plants within a short time in a single campaign. Many mines and plants have taken advantage of the cooperative plan, whereby keymen in a mine or plant, in addition to the initial training received, are given intensive training in first aid by a Bureau of Mines instructor. Those men who show an aptitude for teaching are selected as tentative provisional first-aid instructors. In order to qualify as a provisional instructor, a tentative instructor must, under the supervision of a Bureau of Mines instructor, train a class of at least six persons employed in the minerals industries in the standard Bureau of Mines course in first aid. After it has been determined that the class has been trained properly, a provisional first-aid instructor's pocket card certificate is issued to the class instructor. The first-aid instructor can renew his pocket card certificate each year by training or retraining at least six persons connected with the mineral industries to satisfactorily pass an examination given by a Bureau of Mines representative. After five yearly renewals of a provisional instructor's pocket card certificate, an engraved, permanent instructor's certificate and a permanent instructor's pocket card certificate are issued to the instructor."

Feb 1, 1955

By Christopher Mark, Anthony T. Iannacchione

Falls of ground continue to be one of the most serious causes of injury to U.S. miners. Of the 256 fatal injuries that occurred in mining between 1996 and 1998, 52 (20%) were caused by falls of ground (Table I). Falls of ground affect some sectors of the mining industry more severely than others. For instance, nearly 40% of the 98 coal mine fatalities between 1996 and 1998 were caused by falls of ground. Underground miners are at much greater risk than surface miners. Nearly half (45 out of 101) of underground mine fatalities were attributed to roof, rib and face falls, while less than 5% of the 155 surface fatalities were caused by falls of highwalls or slopes. Sources of Data All of the injury data examined in this study were derived from MSHA’s Fatal Investigation Reports (www.msha.gov)and the MSHA accident database. Because falls of ground often result in serious injury, MSHA Fatal Alert Bulletins and Fatal Investigation Reports provide a useful snapshot of ground control issues in the mining industry. MSHA requires that mines file a report on every reportable accident that occurs, containing information on the accident’s location, severity, classification, activity, and nature of injury, etc. A short narrative is generally included as well. Accident reports can be searched by many of the above fields. From 1996 to 1998, miners suffered a total of 55,096 injuries, which ranged in severity from death (degree 1) to injuries with no days away from work nor restricted duty (degree 6). Six percent of the total injuries were from falls of ground, including machine accidents where caving rock was coded as the source. As the data in Table II indicate, 98% of all non-fatal fall of ground injuries occurred in underground mines, with underground coal mines accounting for 83% of the total. Table II also shows the distribution non-fatal fall of ground injuries by severity and commodity. The injuries are classified into Lost Time Injuries that resulted in permanent disability (degree 2) or days off work (degrees 3-4), and Injuries Without Lost Time that resulted in no more than restricted duty (degree 5-6). Overall, groundfall injuries appear to be more serious than other types of mining injuries. 65% of all ground fall injuries resulted in lost time compared to 54% of all types of mining injuries.

By Jueun Lee, Jong-Hwa Yoon, K. Rider, Bernard J. Martin

Whole body vibration is known to affect movement accuracy [1], however little is known about changes in the organization of movement and movement strategies used to limit the influences of perturbations. The specific aim of this work is to analyze the motion and coordination of upper body segments of seated operators performing reaching tasks under whole-body sinusoidal vibration exposure and simulated vehicle ride motion. The long-term objective is to model reach coordination and predict the dynamic behavior of the upper body motion under vehicle vibration exposure. Method The reach task consisted of pointing with the right hand index finger to targets located on touch screens placed in front of the subject, 45° overhead and 90° to the right in the mockup cabin of an HMMWV placed on a 6 DOF ride motion simulator. The task was performed under stable (no vibration) and vibration (sinusoidal vibration or simulated ride motion) conditions. A motion capture system was used to record kinematic data of reflective markers to recreate body link trajectories. Joint angles (torso, shoulder and elbow; Figure 1) were then computed using quaternions. Coordination between body links was defined as a) the joints angle-versus-angle relationships between the upper arm and lower arm, and b) the joint motion onset relationships between torso, upper arm and lower arm in the time domain. Results Angle–versus-angle relationships. The relationship between upper arm vs. lower arm angle and torso vs. upper arm angle for a far forward reaching movement in the stable (solid lines) and vibration conditions (dotted lines) are illustrated in Figure 2. Fig 2A compares the control condition with a 4 Hz lateral vibration while Fig 2B compares the control condition with a 6 Hz vertical vibration. It appears that under vibration exposure the reduced upper arm extension is compensated by an increase in torso flexion. This effect is seen in the last phase of the movements (encircled areas). In addition, the lower arm extension is delayed under 6 Hz vertical vibration (Fig 2B left panel). Time of joint motion onset. The timing relationship between torso, upper arm and lower arm is largely a function of the target to be reached. Examples of delays between body links are illustrated in Figure 3. The control condition is compared to a 6 Hz vertical vibration for three

Jan 6, 2006

By Lloyd G. Fitzgerald

"The dangerous nature of explosives makes them a potential hazard wherever they are used, but they are likely to exercise their greatest harmfulness under conditions inherent in coal mining. The ease with which explosives can be detonated and the suddenness and violence with which they detonate require great care in their handling and use, if acci-dents are to be avoided. Campaigns have been waged by the manufacturers, the Federal Bureau of Mines, coal-mining companies, and other agencies to educate users of explosives in their dangers and in their proper use and care.Probably 95 percent of the explosives accidents can be attributed to poor judgment, carelessness, negligence, or chance taking. In many explosives accidents it is difficult to determine the cause definitely, as the evidence of the origin is destroyed by the blast and frequently those involved have been killed. Survivors of the accident often are of little help in determining the cause, as the accident occurs so suddenly they cannot tell what happened or prefer not to divulge the information they have because it may point to their own carelessness.A survey has indicated that about 10 percent of all fatalities in coal mines were caused by explosives accidents (excluding gas and dust explosions initiated by explosives). A list of explosives accidents by States, from 1925 to 1932, classified according to the severity of the accidents, indicated that Kentucky and Wyoming had the greatest number of fatalities resulting from explosives accidents. Records of the Bureau of Mines show that 14 coal-mine explosions occurred from January 1 to June 1, 1943. Explosives were involved in four of these explosions. Black powder caused two of the accidents and permissible explosives used in a nonpermissible manner the other two. These statistics are mentioned to show that explosives are still causing severe accidents.Elimination of the hazards associated with explosives begins on the surface. Storage magazines should have no opening, except for entrance and ventilation; ventilators should be screened effectively to prevent the admittance of sparks as well as to prevent unauthorized entrance. The interior should be kept clean and dry, and the floor should be of nonsparking material with no metal exposed. The surrounding area should be kept free of combustible material for not less than 25 feet (and preferably 50 feet) in all directions. Storage magazines should be fire-resistant and reasonably bulletproof."

Aug 1, 1944

By E. P. Youngman

In the Unfederated Malay States, with the exception of Johore, the rights of suzerainty, protection, and administration were transferred by giam to the British Government in 1909. In the States of Kelantan, Trengganu, Kedah, and Perlis, the rulers are assisted by State Councils and by British advisers appointed by the British Government.3 With respect to Johore, the largest, richest, and most highly organized of the Malay States not in the Federation, the treaty of December 11, 1885, with Great Britain, defined the relations of the State to the British Govern- ment and allowed the Maharaja to assume the title of "Sultan"; an amendment to this treaty (May 12, 1914) provided that the Sultan should be advised by a British officer, the General Adviser. ...... The political organization of the States is reflected in the mining legis- lation, Johore being the only one having a comprehensive code. The mining enactments now in force, according to the High Commissioner for the Malay States, are as follows:

Jun 1, 1932

By George Quackenbos

The principal objective of this Program is the design, fabrication and testing of an Environmental System for operation in underground mines, to assess the effect of various mining systems on the contaminant levels near the mine face and within return airways. In order to determine the effect on airborne contamination in mines resulting from the development of new mining techniques, equipment and control systems, a Comprehensive Monitoring System is required to assess such contamination levels at critical and strategic locations and relate this information with ventilation parameters. The three variables to be sensed on a continuous basis are airborne dust concentration, methane concentration and ventilation air velocity. Each Monitoring Station will consist of a self-contained unit containing a power source and sensors to monitor the three above mentioned parameters. Ruggedness, reliability, ease &apos;of operation and intrinsic safety are important design objectives. Data gathered by each Monitoring Station will be fed to a Central Data Acquisition System by means of a portable transfer unit.

Jan 1, 1982

By Wilbur I. Duvall, Thomas C. Atchison, Joseph M. Pugliese

Short cylindrical charges were detonated in drill holes in rock to determine the effect that decoupling ( defined as the ratio of the radius of the hole to the radius of the charge ) has on the strain - generating abilities of explosions in rock . The amplitude and period of the strain pulses produced in the rock were studied as a function of distance , size of charge , and decoupling . The main results of these studies were that , for a given distance and size of charge , the amplitude of the strain pulse decreases as decoupling increases and the period of the strain pulse decreases at first and then increases as decoupling increases . A simplified theory of decoupling is presented that satisfactorily explains the experimental results . The information presented makes it possible to predict the effect of decoupling on explosiongenerated strain pulses in rock and thus helps the explosives user evaluate the effect of decoupling on his blasting .

Jan 1, 1964