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Assist in controlling or extinguishing fires that occur in abandoned mine lands (AML) by providing a compilation of information on past fire control projects, the estimated extent of the current problem, and factors affecting the occurrence, propagation, and extinguishment of AML tires. Conventional fire control methods and their probable effectiveness are evaluated. Background Fires that occur in abandoned coal mines, waste banks, and coal outcrops constitute a serious health, safety, and environmental hazard from toxic fumes, deterioration of air quality, and subsidence. Although fires on AML occur in every coal-producing State, the severity of the problem varies, with most underground fires occurring in Kentucky, Pennsylvania, and Wyoming. Surface fires are prevalent in Kentucky, Pennsylvania, and West Virginia. Methods to extinguish or control AML fires, including excavation, fire barriers, and scaling, are generally expensive and have a relatively low probability of success (see figures 1 and 2). Bureau of Mines Study The Bureau compiled information from a variety of sources and found that the problem of AML fires is a serious one. Such fires can involve a high degree of hazard and can be difficult and costly to control. AML fires usually involve smoldering combustion in outcrops, waste banks, or abandoned mines. Given the nature of these fires, it is unlikely that the extent of the problem or the cost of solutions will decrease in the near future.

Jan 1, 1992

By Jeffrey B. Osmint

The Bureau of Mines Information and Analysis Directorate collects worldwide data on virtually every commercially important nonfuel mineral commodity. These data form the base for tracking and assessing the health of the minerals sector of the U.S. economy. The Bureau's data collection activity was instituted by the 47th Congress in an appropriations act of August 7, 1882 (22 Stat. 329), which placed the collection of mineral statistics on an annual basis. The most recent authority fur the Bureau of Mines survey activity is the National Materials and Minerals Policy, Research and Development Act of 1980 (Public Law 96479, 96th Congress), which strengthens protection fur proprietary data provided to the U.S. Department of the Interior by persons or firms engaged in any phase of mineral or mineral-material production or consumption.

Jan 1, 1991

By J. L. Konchesky

The Bureau of Mines investigated the main reactions of coal gasification by steam. Coal (minus 70 mesh)-water slurry was fed into a laboratory-scale tube-coil gasifier to show the effects of residence time (0.6 to 1.1 sec), steam-coal ratio (2 to 11 lb/lb), and temperature (1,600° to 1,900° F), at about 1-1/2 atm. Devolatilization was very rapid: about 70 pet of the coal's volatile matter evolved within 0.6 sec at about 1,600° F; temperature increase released more volatile matter until about 95 pct was driven off at 1,900° F. Devolatilization was not increased by raising steam concentrations and was only slightly increased by extending residence time. Below 1,600° F, there was no evidence of the steam-carbon reaction, but at 1,900° F more than 80 pct of the coal's fixed carbon was converted to gas; the conversion was increased Significantly by increased residence time and steam concentration. The water-gas shift reaction occurred simultaneously with devolatilization, and the steam-carbon reaction, approaching equilibrium with increased residence time and temperature and decreased steam concentration.

Jan 1, 1969

By J. J. Henn

A process is evaluated for recovering metallurgical-grade manganese are from the low-grade manganiferous iron ores of the Cuyuna Range, Minnesota. The process, developed by the Bureau of Mines, employs high-temperature sulfatization of the are to form manganese sulfate and reduction of the are to convert the iron to a magnetic oxide. The roasted ore is water-leached to dissolve the manganese sulfate, which is then separated from the leach residue, is crystallized, and is calcined to produce the manganese product. Iron is recovered from the leach residue by magnetic separation, and is pelletized and calcined to produce byproduct iron ore pellets. The fixed capital cost for a plant yielding a product containing 100 tons of manganese per day is $19.6 million on a mid-1970 basis when the raw are contains 4.84 percent manganese. The estimated operating cost of the plant is $211 per ton of contained manganese. Graphs are included to show the effects of ore cost and varying manganese content of the raw ore on the estimated operating cost.

Jan 1, 1972

By William A. Vogely

STRIKES in the steel and copper industries adversely affected production in the minerals industry in 1959. Because of an excellent first half of the year and rapid recovery of production after the steel settlement, most statistical indicators were higher than the recession-recovery year 1958. Domestic production of metals declined by 9 percent, but nonmetals (except fuels) increased by 8 percent. Ferrous-metal mine production was down 8 percent, and base-metal mine production was off 11 percent. Employment was high during the first half of the year, but averaged lower than in 1958. Stocks continued to decline as a whole, but crude metal ore stocks actually increased. The indexes of stocks at yearend were still high as compared with 1955. Prices were firm throughout the year. A new index of average unit mine value is presented for the first time in this review; it showed a very slight decline in average mine realization for 1959. The percentage share of supply from imports increased in some commodities, due in large part to the shutdown of domestic iron, steel, and copper industries.

Jan 1, 1960

Objective Develop field measurement and computer modeling methods to predict the potential for hang-ups and structural failures in underground mine ore paws. Background Analysis of Mine Safety and Health Administration (MSHA) accident statistics has identified ore pass hazards as a significant safety problem in underground metal mines in the United Stales. Recent ore pass failures have underlined the lack or ore pass design methods ant1 standards available to both MSHA and mine engineers. Injury and fatality data for the 20-ycar period between 1975 and 1095 show that nearly 75% of the injuries were directly or indirectly related to pulling or freeing ore pass chutes, the use of hand tools, falls or broken rock, and structural failures or chutes or gates and ore pass walls.

Feb 1, 1998

By John A. Breslin

Three scale models of coal mine entries and mining machines were constructed by the Bureau of Mines to study the effects of ventilation parameters on dust concentrations where mining personnel would be working. A one-fifth-scale model of a coal mine entry with a drum-type continuous-mining machine and a one-sixth-scale model of an entry with a twin-borer-type machine were used as well as a one-fifth-scale model of a longwall face with a double-drum shearer. Methane was used as a tracer gas to simulate respirable dust in the models. The distance of the end of the brattice or tubing from the face was found to be more important than the airflow rate for the drum-type machine. Dust reductions greater than 90 pct were shown to be possible with a secondary ventilation system used with the twin borer and a dust collector mounted on the longwall shearer. Cutting-head speed had a significant effect on concentrations at typical positions of miners with the drum-type machine and longwall shearer but not for the twin borer.

Jan 1, 1976

By J. M. Stuve

This Bureau of Mines investigation measured the low-temperature heat capacities of FeOC1(c) and FeC13(c) in the temperature ranges of 6 to 305 K and 4.6 to 300 K, respectively. The standard entropies (S°, 298.15 K) of FeOCl(c) and FeC13(c) were derived as 19.73±0.03 cal/deg-mole and 35.33±0.07 cal/deg-mole. A large lambda transition was observed in the heat capacity of FeC13(c) at 8.4 K. The standard enthalpy of formation (?H°f, 298.15 K) of FeOC1(c) was determined to be -98.23±0.22 kcal/mole by HC1 solution calorimetry. High-temperature enthalpy measurements (H-H298.15) of FeOC1(c) were determined to 700 K by precision drop calorimetry. Standard thermodynamic formation data and related functions were tabulated at various temperatures for FeOC1(c) and FeC13(c).

Jan 1, 1980

Design a high-production coal mining machine with inherent low dust generation and low frictional ignition potential. Approach Constant depth linear cutting (CDLC) provides a longterm solution to excessive dust generation from shearers and continuous mining machines through new design of the rotary drum culling system. Problems with rotary drum systems, which must be eliminated to control the dust generation at the source, include the effect of a con¬stantly varying depth of cut using fixed bit spacing, secondary fragmentation of already broken coal and, frictional heating of bits and entrainment of dust by fanning action due to high drum rotational speed, Each bit on a rotary drum enters the coal face at zero depth of cut, goes to some maximum depth at the horizontal centerline during sump, and exits at zero depth.

Jan 1, 1989

By Mathew P. Oommen, Jeffrey L. Kohler

Computer-aided loadflow and fault analyses of mine power systems are routinely conducted to ascertain system performance and also to provide information to assist in the protection and coordination of these systems. Three-winding transformers are frequently encountered in mining applications, typically at continuous miner and longwall sections where there exists a need for dual utilization voltages. These transformers are often modeled as a three-bus system neglecting the secondary to tertiary winding impedance and the effect of base changes. This paper analyzes the impact of more accurate transformer models on voltages and fault currents which are realized from loadflow and fault studies of mine power systems.

By D. S. Colby

The productive capacity of natural gasoline and cycling plants in the United States or. January 1, 1954, was 926 thousand barrels per day, according to the Bureau of Mines biennial survey. This represented an increase of 114 thousand barrels per day during the 2-year period since the last survey. In the previous 2-year period, capacity had increased 164 thousand barrels per day. The total number of plants increased from 521 on January 1, 1952, to 535 on January 1, 1954. The number of operating plants increased from 506 to 521. The major increases in capacity took place in Texas, Illinois, Oklahoma, Louisiana, and New Mexico, with the absorption-type plant continuing to account for most of the new construction. In 1954, however, 6 plants reported using a refrigeration process whereas only 1 plant reported this in 1952. The number of operating compression-type plants continued to decline and combination plants showed a decline this year because a number of these plants were reclassified as absorption-type.

Jan 1, 1954

By Seth C. Schaefer

The Bureau of Mines studied the standard free energies2 of formation of ferrous fluoride (FeF2) and ferric fluoride (FeF3) with high-temperature galvanic cells employing calcium fluoride doped with 1 mole-pet yttrium fluoride as the electrolyte. A free-energy change for the cell reaction Fe (s) + NiF2 (S) = FeF2 (S) + Ni (s) together with the standard free energy of formation of nickel fluoride yields a standard free energy of formation of ferrous fluoride from the elements of ?GF° = -168.74 + 30.63 x 10-3T ± 0.41 kcal/mole (897-1,098 K). (2) Combining the standard free energies of formation of magnesium fluoride, ferric oxide, and magnesium oxide with the free-energy change for the overall cell reaction 3MgO(s) + 2FeF3 (s) = 3MgF2 (S) + Fe2 03 (S) (3) gives a standard free energy of formation of ferric fluoride from the elements as ?Gf° = -281.45 + 90.46 X 10-3T ± 0,67 kcal/mole (880-935 K). (4) Free energies and equilibrium fluorine pressures for the two univariant equilibria of the Fe-F system are tabulated and illustrated.

Jan 1, 1975

By John Durkin

Information on vertical magnetic noise in the voice frequency band, both within and above coal mines, is needed for the evaluation of through-the-earth baseband electromagnetic communications at mines where horizontal loop antennas are used. This report discusses the theory of the source of electromagnetic noise, the propagation of this noise to an observation point above a mine, and its interaction with the local earth conductivity structure, which gives rise to vertical magnetic noise. The relationship of surface noise to underground noise is also discussed. Bureau of Mines investigators made surface and underground vertical magnetic noise measurements at a number of coal mines located through- out the United States. These data were modeled through regression analysis to characterize expected noise levels. The results are presented, including results in one-third octaves for use in evaluating the expected performance of through-the-earth communication systems by articulation-index studies.

By S. D. Maksirnovic, Fred N. Kissell

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by (the Bureau of Mines. This report describes three gob degasification studies ,conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole . The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore- hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By E. Morrice

The effect of the temperature of SmF3-LiF electrolyte on the electrolytic preparation of samarium-cobalt alloy by the consumable cathode technique was investigated. The temperatures of the cathode zone, alloy collection zone, and samarium oxide (Sm203) feed zone had to be controlled carefully to obtain a satisfactory samarium-cobalt alloy product. Any appreciable deviation from certain temperature values adversely affected yield and product quality.

Jan 1, 1971

By T. T. Campbell

This report describes the development of new electroplating baths from which tin-nickel alloy plate was deposited. Although tin-nickel plate can be deposited from an aqueous ammonium bifluoride bath, the corrosive nature of this bath has served as a deterrent to its use. The Bureau of Mines felt that more general acceptance of this new alloy plate would follow if neutral or alkaline baths could be developed. Promising results were obtained from electrolytes containing both tin and nickel chlorides dissolved in triethanolamine-hydrochloric acid or in ethylene glycol hydrochloric acid baths. Current efficiencies close to 100 percent were obtained with these baths. Research revealed that tin-nickel plate could be produced from organic solvents or from mixed aqueous-organic electrolytes. The composition of the alloy deposit - 65 percent tin and 35 percent nickel - was found to exhibit the same single-phase structure that is obtained from the commercially accepted fluoride-type bath.

Jan 1, 1959

By F. M. Carlson

Comparisons are made between the results of the Buckley-Leverett and Kern solutions, which describe immiscible displacement of oil by gas in a linear system and the results obtained from a less restrictive numerical model. This model takes into account the effect of compressibility of the oil and gas and the effect of allowing changes in the amount of gas in solution in the oil. These effects are best exemplified by imposing large pressure drops across the system. With these large pressure drops, comparison of the model solution with the Buckley-Leverett solution reveals that the Buckley-Leverett solution provides estimates of recoveries at breakthrough of the gas that are too low. In contrast to the model, the Kern solution predicts breakthrough recoveries that are too high. A modification to the Kern solution is presented to facilitate more accurate predictions of recovery at gas breakthrough for gas injection at pressures higher than the saturation pressure of the oil.

Jan 1, 1974

By Fred N. Kissell, R. J. Bielicki

In this report the importance of diffusion in controlling the emission of methane in mines is examined. An in-situ diffusion parameter is defined and calculated for a hypothetical unfractured lump of coal in the Pittsburgh and Pocahontas No. 3 coalbeds. The values obtained are similar to those obtained with lump coal in laboratory experiments.

Jan 1, 1972

By Marc T. Filigenzi

Two of the major ground control safety issues confronting underground mine operations today are shaft pillar stability and the failure of rock around active mine openings. Failure of a mine shaft can lead to the entrapment of workers. Failure of rock around active underground mine openings can lead to roof falls, which in turn can result in worker injuries and fatalities. Finite-element analysis has proven to be a reliable method for predicting stresses and displacements around underground mine openings. However, this is a complex and time-consuming technique and is not used as often as it could be in mine planning. The purpose of this paper is to demonstrate one technique developed at the Spokane Research Center that allows the user to create a finite-element model of a two-dimensional section of an underground mine in a relatively straightforward manner. This model is then used to calculate stresses, displacements, and safety factors around mine openings. With this information, mine planers can evaluate the stability of mine openings as well as the stability of pillars and mine shafts. This analysis will help develop mining sequences and layouts that minimize stresses in that section of the mine. This, in turn, should minimize the occurrence of shaft failure, roof falls, and other hazards associated with underground mining.

By David F. Smith, F. A. Hartgen

"Incidental to a cooperative investigation with the Carnegie Institute of Technology and the International Combustion Engineering Corporation on the burning characteristics of a powdered coal and the powdered semi-coke therefrom, the U. S. Bureau of :alas has determined the relative temperatures at which rapid self-heating occurs in these two fuels. Determinations were made on various screen sizes of the two fuels. Chemical analyses on different sizes were made in the bureau's Coal Analysis Laboratory, of which H. M. Cooper is in charge. The true densities were determined b the method given in Bureau of Mines Technical Paper 8.4The apparatus used in the determination of the temperatures for rapid self-heating was similar to that used by Wheeler A 10-gram sample of the fuel was placed upon a screen in a glass tube enclosed in a vertical electric furnace. The tube was surrounded with sand. One thermocouple -as imbedded in the sand and another in the fuel. Measurements of the temperatures were obtained at regular intervals with a recording potentiometer, as the furnace temperature was uniformly raised. Dry air was passed down through the fuel samples at a uniform rate of 123 c. c. per minute; the temperature of the air was substantially that of the furnace."

Oct 1, 1929