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By Susan M. Moore

According to the Mine Safety and Health Administration (MSHA) injury database, 227 knee injuries were reported in underground coal mining in 2007 [ 1]. Low-seam coal mines are those with extremely low working heights (<42?). Gallagher et. al [2] found that the average cost per knee injury in low-seam coal operations was $13,121.29. Thus, it can be estimated that the financial burden of knee injuries was nearly three million dollars in 2007. Pressure applied to the knee while kneeling and crawling is likely a risk factor. Typically, mine workers utilize kneepads to better distribute the pressures at the knee; however, their ability to reduce the stresses at the knee is unknown. The objective of this study was to determine the pressure applied to the knee during static postures used in low-seam mining while not wearing kneepads and while wearing two kneepads commonly used in the industry (one articulated and one non-articulated).

Jan 1, 2009

By L. C. IlsLey

"Nearly every piece of electrical equipment used in mines ""breathes."" In other words, motors, controllers, rheostats, switches, and other similar equipment, even though encased in seemingly tight compartments, breathe in the atmosphere that surrounds them.As the apparatus is used, the temperature of metallic parts is changed generally in positive direction through the heat by friction and the heat due to the electric current. When the apparatus is idle it gradually cools down to the temperature of the surrounding atmosphere.This increase of temperature during operation and return to normal temperature when operation stops alternately raises and lowers the temperature of the atmosphere within the compartments which, in strict accordance with Charles' law -will expand or contract in proportion to any given temperature change.As compartments are not gas-tight, such expansion and contraction will force the atmosphere out of the compartment =on expansion and suck the surround¬ing atmosphere into the compartment during contraction, hence the term ""breathing.""Investigators2 of explosion-proof equipment have recognized that such an interchange would take place and have designed their equipment to safeguard possible explosions within the compartments."

Jun 1, 1927

By Henry G. Dorsett

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 73 chemical compounds and mixtures, 29 drugs, 27 dyes, and 46 pesticides. Information is given on ignition temperatures of cloud and layer, minimum igniting energy, minimum explosive concentration, percent of inert dust required to prevent flame propagation, limiting oxygen concentration in the atmosphere to prevent ignition, and pressures and rates of pressure rise at dust concentrations of 0.1, 0.2, 0.5, 1.0, and 2.0 ounces per cubic foot. Explosibility indexes are computed where data are available to permit comparison of the relative explosion hazard. Variations of explosibility parameters with chemical composition are discussed. General means for minimizing the dust explosion hazard are reviewed.

Jan 1, 1968

By Marting J. Gavin

The twentieth century has often been spoken of as the age of petroleum, and from many viewpoints it can be justly considered so. Certainly the petroleum industry is one of enormous importance to this country, industrially, financially, and economically. The United States, however, at present producing over 60 per cent of the world's total output of petroleum, is not producing petroleum at a sufficient rate to provide for its own domestic, consumption. For several years this country has been importing increasing quantities of crude and partly refined oils from Mexico, and has been drawing heavily on domestic stocks of petroleum. Production in the United States is increasing, but it is not increasing at the same average rate as domestic consumption, nor is it probable that in the future domestic production will increase sufficiently to satisfy the demands of domestic consumption, but on the contrary, in the opinion of those best qualified to know, the peak in the curve of domestic production of crude petroleum will be reached in a comparatively few years, whereas the consumption of petroleum and its product will increase at a continually growing rate. This country, then, must turn, and as the increasing imports from Mexico indicate, is turning to other sources than the crude petroleum, produced in this country to make up the deficit between domestic production and domestic consumption of petroleum and its products,

Jun 1, 1920

By Ivette E. Torres

Table 8 provides data for the estimated value of world export trade of all mineral commodities from 1980 through 1991. It also provides a breakdown of the total into mineral fuels and non fuel minerals. These data have been developed from UN export trade data presented in table 9. The percent distribution and growth of the value of world export by major commodity groups are presented in tables 9, 10, and 11, respectively. In terms of industrial minerals (nonmetals), data in tables 10 and 11 include crude industrial minerals only, while table 8 includes an estimate for other industrial minerals. The 1991 estimates that appeared in the 1991 issues of this publication have been revised. It is typical for this section to review the year prior to the year of review because of the unavailability of data at the time of publication. The aggregated value of export trade in mineral commodities for 1992 was not available at the time of publication. The total value of nonfuel and fuel mineral exports for 1991 was about $616 billion in current (1991) dollars. The value of mineral fuel export trade accounted for about 53 % of the total mineral export trade. In 1980, the contribution of mineral fuel to the value of mineral commodity export trade had been almost 68%. The 1991 world mineral commodity export trade represents a 5.3% decrease (table 8) from that of 1990. The largest decrease was attributed to the decrease of export trade of fuel minerals (5%). The value of non fuel mineral export trade decreased by 4 %. Because the value export trade of all commodities increased by 1.2 %, the share of mineral commodities decreased from 19.2 % to 17.9 % of the total.

Jan 1, 1994

By R. E. Mussler

As part of an overall goal to develop technology that can maintain an adequate supply of minerals to meet national economic and strategic needs, the Bureau of Mines is evaluating a method for selectively extracting nickel and cobalt from low-grade domestic laterites. The method involves electrowinning to recover the metals in pure form; therefore, preliminary laboratory-scale electrowinning tests were conducted in both a nondiaphragm and a diaphragm cell to determine the effect of variables on energy efficiency under controlled conditions. Electrolytes were generally reagent-grade sulfate solutions that were prepared to simulate electrolyte that could be obtained by stripping nickel-and cobalt-rich solvent extraction reagents. Limited tests were conducted with electrolyte generated from laterite leach solutions. Electrical energy consumption in a nondiaphragm cell was 2.06 kwhr/lb Ni with the cell operated at 50° C, a cell feed of 90 g/l Ni, a pH of 3.5, an extraction of 3.2 g/l, and a cathode current density of 20 amp/ft2. The energy requirement decreased with increasing concentration and temperature, and increased with increasing. extraction and current density. At 50° C, energy consumption in the nondiaphragm cell was 21 pct greater than in the diaphragm cell, but it was only 5 pet greater at 65° C. For this reason and because of overall cost considerations, operation at 65° C with the nondiaphragm cell was preferred. Smooth sheets of cobalt were obtained by electrowinning in a nondiaphragm cell at selected temperatures from 50° to 85° C and with cobalt concentrations from 55 to 87 g/l. The energy consumption (1.48 kwhr/lb) was 22 pet lower with a cobalt concentration of 75 g/l and a cell temperature of 65° C than with a cobalt concentration of 55 g/l and a cell temperature of 50° C.

Jan 1, 1981

By Wing G. Agnew, John A. Johnson, McHenry Mosier

"INTRODUCTION AND CONCLUSIONSThe first three reports of investigations 5/ in this series, pertaining to the investigation of stemming at the Mount Weather Testing Adit dealt with the dust produced by blasting, the effect of stemming on gases generated by blasting, and the relative advantages and disadvantages of different types of stemming and no stemming when used with 60-percent ammonia gelatin dynamite.This report covers an investigation of the length of stemming material through which a primer will fire and detonate a charge of dynamite, such as a missed hole.The practice of drilling a new hole a foot from a missed hole to blast out the missed hole should be prohibited. It is dangerous, as is evidenced by the number of miners killed through drilling into missed holes. It is even more hazardous in a mine on a multiple-shift basis, in which the same miners do not drill succeeding rounds."

May 1, 1942

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

C.5 Safety Equipment and Control Devices Safety equipment and control devices serve two principal functions in mine escape hoists. First, they can be used to provide important safety features such as protection against overspeed, over¬travel and undertravel. Second they can be used to automate or partially automate the operation of the escape hoist. Typical equipment available is described in the following section. 1. Simplex and Lilly Hoist Controllers Manufacturers: Logan Actuator Co. 4956 No. Elston Ave. Chicago, Illinois 60630 312-736-7500 The Simplex and Lilly Controllers provide a means for electrically shutting off the power to the hoist and the energy to physically set the brakes in the event of overspeed, overtravel, undertravel and failure to begin deceleration within sufficient distance

Jan 1, 1976

Lower costs associated with hands-on training in donning and using a CSE ,self-contained self-rescuer (SCSR). Background In June 1987, the Mine Safety and Heath Administration (MSHA) issued an Emergency Temporary Standard (ETS) requiring that all persons entering underground coal mines must be given bands-on SCSR training. The ETS will shortly be replaced by a new standard requiring this hands-on training. Bureau of Mines research has shown that the most effective means of delivering this training is to have the trainee go through a six-step training procedure while in a kneeling position. Once the miner has looped the neckstrap over his or her head, he or she completes the donning sequence in this order: 1) activate oxygen; 2) insert mouthpiece; 3) put on nose clips; 4) put on goggles; 5) adjust neck and waist straps; and 6) replace miner&apos;s cap and prepare to move out. This procedure is repeated until the miner demonstrates that he or she is proficient at the task.

Jan 1, 1988

The National Institute of Occupational Safety and Health has classified diesel exhaust as a potential human carcinogen. Though standards for diesel particulate matter (DPM) in the work place have not been established, concern for the health of miners is prompting mine operators to consider methods for reducing worker exposure to diesel exhaust. Approach One of many methods for reducing DPM being investigated by the Bureau of Mines is the use of additives in diesel fuel to improve combustion. Research Results Three fuel additives have been tested in Caterpillar and Deutz diesel engines which are similar to types used in underground mines. One iron-based additive containing ferrous picrate had no effect on emissions. A second iron-based additive containing ferrocene reduced DPM between 5 and 45 pet depending on engine operating conditions. The 37-pct reduction for an 8-minute duty cycle, which includes a wide range of transient loads and speeds, is considered to represent in-mine performance.

Jan 1, 1990

By Seth C. Schaefer

The Bureau of Mines has determined the standard Gibbs energies (AGf°) of CoS1.035 (cobalt sulfide) and Ni2.515S2 (nickel sulfide) with high-temperature galvanic cells using stabilized Zr02 (zirconia) as the electrolyte. Potential measurements were obtained for the cell Pt, CoS1.035, CoO, S02(g, 1 atm)//Zr02//02(g, 0.0114 atm), Pt, with the overall cell reaction C0S1.035(c) + 1.535 02(g, 0.0114 atm) = CoO(c) + 1.035 S02(g)¬ These results, combined with the best available data for ?Gf° of CoO and S02 from the literature, give the standard Gibbs energy of formation of CoS1.035 for the reaction Co(c) + 0 5175 S2(g) = CoS1.035(c) ?Gf° = -38.890 + 18.87 x 10-3T ± 0.185 kcal/mole (866.0 - 1,104.9 K), where temperature (T) is expressed in kelvins. Similar measurements were obtained for the cell Pt, N12.515S2, NiO, S02(g, 1 atm)//Zr02//02(g, 0.0122 atm), Pt, with the overall cell reaction Ni2.515S2(c) + 3.2575 02(g, 0.0122 atm) = 2.515 NiO(c) + 2 S02(g). Combination of these results with data for ?Gfo of NiO and S02 from the literature yields the standard Gibbs energy of formation of Ni2.515S2 for the reaction 2.515 Ni(c) + S2(g) = Ni2.S1SS2(c) ?Gf° -65.377 + 24.67 x 10-3T ± 0.541 kcal/mole (968.6 -1,053.7 K).

Jan 1, 1981

By Raymond B. Ladoo

Deposits of talc are known in many districts in Canada but at the present time active mining operations are reported only in Ontario . Here three companies are now operating, two of which, George H. Gillespie & Co. , Ltd. , and the Anglo- American Talc Co. , are at Madoc . The operations of the former company are probably the largest and best known in Canada . The writer , in his capacity as an engineer of the U. S. Bureau of Mines , was permitted by this company to make an inspection of its mine and mill in June, 1920 , and study the methods employed . This information was desired for comparison with methods employed in the United States . The following description is based on observation made during this visit , supplemented by data supplied by the company .

Sep 1, 1920

By J. C. Hartley

The most important single operation in mining is the ventilation of underground areas in a manner conducive to the health and safety of employees. Adequate volumes of pure air must be supplied at the working faces, along the haulageways, and wherever men work, so as to dilute and carry away the methane liberated from the coal and adjoining strata, noxious gases evolved by the use of explosives, and the carbon dioxide exhaled by men and formed by oxidation of carbonaceous material, as well as any other gases, and also dusts which may be found in mine workings. A sufficient quantity of air must also sweep abandoned or worked-out areas of the mine to prevent the accumulation of gases, where sealing methods are not utilized to isolate old workings. Air, in a quantity adequate to meet the needs of the particular mine to which it is applied, is necessary, and supplying it can be made very expensive through failure to observe good practices in its direction and apportionment." Leaky stoppings, doors, and overcasts rob the working faces of air and add to the ventilating cost by burdening the fans with fugitive air,

Jan 1, 1944

By N. H. Coates

As part of a joint program of the U.S. Atomic Energy Commission and the Federal Bureau of Mines for using nuclear energy to supply process heat, the Bureau designed and constructed a pilot-scale simulated nuclear reactor system. Although workable components were developed,5 the simulated nuclear reactor could not be operated continuously at its design conditions of 2,500°F. and 250 p.s.i.g. because the refractory materials used for insulation deteriorated. Replacement of these materials with porous carbon permitted sustained operation at design conditions, and a 1,000-hour demonstration run was completed successfully. No serious operating difficulties developed during the test. Leakage of helium after 1,000 hours was only 3 to 4 std. c.f.h. Inspection after the run revealed no damage to any of the components. Including earlier runs during previous research5 the system has been operated about 4,000 hours, of which 1,120 hours have been at 2,500° F. or higher. The helium-recycle compressor performed satisfactorily with no main¬tenance whatever for 2,445 hours, with about 2,000 hours at 900° to 1,000° F.

Jan 1, 1961

Studies on coal mine drainage sludge densification have led to the following conclusions: 1. Coal mine waters containing iron principally in the ferrous (Fea+) state can be treated by a modification of the commonly practiced lime neutralization process to yield a ferromagnetic sludge. The sludge, presumably composed in large part of a hydrated ferrosoferric oxide (Fe304.xH20), is much denser and faster settling than the ordinary "yellowboy" sludge obtained by lime neutralization and aeration at ambient temperatures. 2. The magnetic sludge preparation technique involves (quantitative) precipitation of iron (largely as Fe(OH)2) by the addition of hydrated lime to a pH of 8.5, separation of the resulting sludge from the aqueous phase, and heating of the sludge concentrate to at least 80 C (176 F), preferably higher, followed by mild aeration. 3. Magnesium, present as Mg2 in most coal mine drainage waters, inhibits the formation of the magnetic sludge. This inhibition can be adequately minimized by keeping the pH below 9.6 during lime addition (thus avoiding the coprecipitation of Mg(OH)2) and by separating the sludge from the bulk of the aqueous phase before the heating step, as indicated in (2) above. 4. Aluminum, commonly present in coal mine drainage waters, also inhibits the formation of the magnetic sludge. This inhibition is of practical significance when the molar ratio of aluminum/total iron is greater than 0.18. Below this value, sludges are still appreciably magnetic, but are bulkier and slower settling than those obtained when aluminum is absent. Unlike magnesium inhibition, aluminum inhibition cannot be minimized by the scheme indicated above, since aluminum precipitates as Al(OH)3 near pH 4 and remains dispersed within the sludge. 5. The limitation on aluminum content is probably the most serious restriction affecting the feasibility of the magnetic sludge process as presently conceived. Nevertheless, a limited review of available water quality data has indicated that, in terms of relative acid and iron loadings, a significant number of major coal mine discharges in the eastern Ohio River basin may be amenable to treatment by a magnetic sludge process. 6. Data from tests on the use of magnetic seeding materials indicate that seeding did not enhance the formation of a magnetic sludge under the experimental conditions employed.

Jan 1, 1971

By F. L. Wideman

Materials handled at metal and non-metal mines in the United States increased 10 percent compared with those of 1965 as a result of expansions in output at existing mines and development of others to meet increasing demands for mineral products. The tonnage of commercial materials mined or quarried increased as did the quantity of waste handled. Crude material from which metal or nonmetal products were derived comprised 71 percent (75 percent in 1964) of the total materials handled. Great strides were made in mining technology and there were indications that, in the future, earth moving by the mining industry will involve materials-handling systems of increasing size and complexity. Materials Handled.-Output of ore and waste at metal and nonmetal mines and quarries in the United States in 1966 totaled 3,518 million tons (3.213 million tons in 1965). The quantity of materials handled has increased at an average annual rate of 5 percent since 1962. Ore production increased 4 percent over that of 1965, also comparable to the average annual rate of increase in the last 5 years. Waste removal in 1966 increased 25 percent over that of the previous year.

Jan 1, 1967

By C. Melvin Lepper

To provide the U.S. mining and energy industries with information in the selection of seismic detectors for high-resolution applications, the Bureau of Mines evaluated 35 velocity detectors (geophones) and 9 accelerometers. It was found that velocity detectors with natural frequencies from 10 to 100 Hz were effective for seismic studies in the 5-to 600-Hz spectrum and that accelerometers were most effective in the 100-to 1,000-Hz range. Although the accelerometers described in this report performed about equally with the better velocity detectors tested, the accelerometers showed higher output voltage levels at higher frequencies, which is an advantage. It is important that a seismic detector and its intended purpose be matched properly to achieve the intended results in high-resolution applications. There are many factors that could affect proper matching, thus careful selection of the best detector for a particular application must be exercised.

Jan 1, 1981

By Laurance L. Oden

The Bureau of Mines conducted corrosion tests of 18 commercial alloys in H3 P04 -phosphate rock or A1,03 slurry, in 10 pct HF, and in 25 pct H2 SiF6 to simulate three environments anticipated in a Bureau process to extract fluoride values from phosphate rock. Small alloy coupons were rotated in duplicate tests at 4.4 to 21 fps in the slurry at 170° C to determine rates of erosion-corrosion. At 4.4 fps the lowest rates, in mils penetration per year (mpy), were measured for Hastelloy C-276 (<20), Hastelloy B (30), and Inconel 625 (150);the rates increased at 21 fps to 55 mpy, 45 mpy, and 1,000 mpy, respectively. The corrosion rate for all alloys exceeded 40 mpy in either the equilibrium vapor or liquid phases of aqueous solutions containing 10 pct HF or 25 pct H2SiF6 at 100° C. Uniform corrosion in 10 pct HF at 50° C was observed only for Inconel 625 (22 mpy), Hastelloy C-276 (43 mpy), and Illium 98 (17 mpy). Inconel 625 (0.75 mpy), Hastelloy C-276 (1.3 mpy), Illium 98 (1.7 mpy), and Incoloy 825 (0.45 mpy) were attacked uniformly in 25 pct H2SiF6 at 50° C.

Jan 1, 1974

By H. P. Rue

The Bureau of Mines has recently collected two samples of crude oil from wells in the Greasewood Flat, area of northeastern Colorado. Sample 31310 was taken from the Continental Oi1 Co.&apos;s well Briggs No. 1 which came in on September 27,7.931, with a maximum production of 940 barrels per day. Sample 31311 was taken from the Reiter-Foster Oil Co.&apos;s well Ida Johnson No. 1 which came in on August 24, 1931 with a maximum production of approximately 1000 barrels per day. These two samples of crude oil are typical "intermediate base" crude oils according to the classification defined by Smith and Lane. The characteristics of these two samples, as shown by the Hempel analyses, indicate that they are almost identical. They have a very low sulphur content, and the residuum has a low carbon-residue content which would indicate that they are excellent crude oils for refining. Crude oils yielding a residuum which has a carbon-residue content of 4 per cent or less usually make good material for the manufacture of cylinder stocks. The pour points of the samples and the cloud test of the fractions obtained from the vacuum distillation indicate that the Greasewood Flat oil contains considerable wax. The high wax content would cause some difficulty in transmitting this oil through a pipe fine during extreme cold weather.

Jan 1, 1932

By Fred Garcia, William P. Diamond

As part of its mine safety and health research program, the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory, has been investigating the geologic and mining factors influencing methane gas emissions associated with longwall mining. A primary focus of this research has been the consequences of increasing longwall panel dimensions, particularly face width, in gassy coalbeds. Continuous longwall face emission monitoring studies were conducted at two adjacent mines operating in the Pocahontas No. 3 Coalbed, where longwall faces were to be extended from 229 to 305 m (750 to 1,000 ft). Average longwall pass methane emission rates for 229-m (750-ft) wide faces were 61 % (0.072 m31sec (153 cfm)) higher at the VP-3 Mine than at the VP-1 Mine. It was predicted by regression analysis of methane emissions data from 229-m (750-ft) wide faces that extending faces to 305 m (1,000 ft) would increase methane emission rates by only 7%, or 0.009 m3/sec (20 cfm), to 0.144 mysec (304 cfm) at the VP-1 Mine. In contrast, it was predicted that extending faces to 305 m (1,000 ft) at the VP-3 Mine would increase methane emissions by as much as 13%, or 0.029 mysec (65 cfm), to 0.268 dlsec (567 cfm).

Jan 10, 1999