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By Walter C. Lorenz

Samples of materials containing pyrite from various coal mines and coalbeds were studied to compare their compositions and oxidizing characteristics. Pyrite was the only form of iron sulfide identified, but X-ray diffraction, emission spectrography, and microscopic analyses revealed similar suites of minerals and trace elements. The pyrite occurred usually in spherical clusters of very small crystals. The oxidation of pyrite in solutions of PeSO4 and Fe2(SO4)3 and in the presence of an iron oxidizing bacterium Ferrobacillus ferrooxidans, was studied through a manometric technique. FeS04 or Fe2(SO4)3 solutions had no appreciable influence on pyrite oxidation under the test conditions, The bacterium acted as a catalyst, greatly increasing the oxidation rates; however, in three samples that also contained calcites, bacterial oxidation was greatly reduced. The oxidation rates also increased approximately as the percentage of pyrite in the samples increased. For the series of samples studied, there was no definite correlation of the results with the location of the various mines nor with the acidity of alkalinity of the mine drainage.

Jan 1, 1963

By R. V. Ramani

This report is volume 3 of an eleven-volume final report for a Grant completed by The Pennsylvania State University for the Bureau of Mines to develop a dynamic general purpose computer simulation model for underground coal mining. The simulator developed under the Grant has a wide range of possible applications in the design and evaluation of underground coal mining systems from the standpoints of health and safety, productivity, and mine environment. The Master Design Simulator consists of nine free-standing function-oriented subsystem models linked together into an integrated, comprehensive model of an entire mining system. The subsystems comprising the Master Design Simulator include geology and reserves, methane generation, roof support, subsidence, production, rail haulage, cost, water generation,' and ventilation. This volume of the final report describes the Methane Generator subsystem of the Master Design Simulator. This subsystem is used to determine methane emission rates into the mine environment. These flow rates are then used by the simulator in planning primary and secondary ventilation systems, planning a methane drainage system, and analyzing complex ventilation networks. Both steady state and unsteady state gas flows are included, and have been modeled as second order nonlinear partial differential equations. Finite difference equations are used to obtain numerical solutions to the models using a central differencing scheme. An application of the model is presented. The appendices include derivation of the gas flow equations used in the model as well as a users manual for the computer program.

Jan 1, 1974

By Susan M. Moore

The objective of this study was to evaluate the circumstances leading to fall from equipment injuries in the mining industry. Method: The 2006 and 2007 Mine Safety and Health Administration annual injury databases were utilized for this study whereby the injury narrative, nature of injury, body part injured, mine type, age at injury, and days lost were evaluated for each injury. Results: The majority of injuries occurred at surface mining facilities (~60%) with fractures and sprains/strains being the most common injuries occurring to the major joints of the body. Nearly 50% of injuries occurred during ingress/egress, predominately during egress, and approximately 25% of injuries occurred during maintenance tasks. The majority of injuries occurred in relation to large trucks, wheel loaders, dozers, and conveyors/belts. The severity of injury was independent of age and the median days lost was seven days; however, there was a large range in severity. Impact on industry: From the data obtained in this study, several different research areas have been identified for future work, which include balance and stability control when descending ladders and equipment design for maintenance tasks.

Jan 1, 2009

By K. K. Kershner, J. G. Donaldson

This investigation was conducted to obtain data on optimum conditions for chloridizing metal sulfides . Salt- roasting galena at 450° C for 8 hours chloridized 75 percent of the lead ; in an equal time of treatment at 750° C , the process chloridized 42 percent of the zinc in sphalerite . Hydrogen chloride at 500° C completely chloridized galena in 15 minutes , and at 600° C converted all of the zinc in sphalerite to the chloride in 4 hours .

Jan 1, 1963

By RUSSELL S. DAVIES, Andrew Allan, John W. Buch

This is a progress report for the period February 1, 1949, to August 15, 1949, covering experiments with lightweight shearing machines for developing thin, steeply pitching anthracite beds. The over-all objective at the time an underground test section was established on July 30, 1946, was to improve mining above the gangway by developing methods for mechanization of pitch mining. Following the preliminary cutting tests in the gangway with the German machines, it became evident that the use of machines of this type indicated advantages for development work that could not be overlooked and warranted investigation. An agreement was reached with the cooperating company that this be done. Thus, the objectivo in the period covered by this report has been to obtain operating data to uso in comparing hand and machine methods of driving development openings. In obtaining the machine-mining data, 78 feet of gangway, 108 feet of heading, and 80 foot of chute work were driven. Hand-mining data are authentic for the mining condition. It has been shown that full mechanization is two and one-half times as fast as conventional hand methods on a lineal-feet- advance-per-shift basis and costs but little more than one-third as much. Tho machines are air-powered; there is less shattering of the coal bed by blasting; water sprays are used to allay' dust; coal is loaded by machine; no rock is taken; timber is not dislodgod by heavy blasting charges; and it may be said, except for the development of a means for transporting timber to the face, that the tasks for the miner are less arduous, and the working face equally as safe, or safer, than in driving by hand. Face timbering remains the greatest time- consuming cycle item, and steps are being taken to correct this. More than 50 percent of the cycle time is now usod for face-timbering work.

Jul 1, 1951

By M. W. Pullen

It is recognized that the determination of electrical resistivity of the earth within a given area may furnish information concerning the location of certain mineralized strata of economic importance. Present knowledge of the electrical resistivity of the various rock formations is almost nil, and the geophysicist who is detailed to make a survey of an area without any data as to the relative resistivity of the underlying rocks is greatly handicapped. Such surveys are usually made within areas known to contain mineral deposits to aid in locating desirable points for drilling. Usually these areas have been prospected by diamond drilling, and drill cores of the various rocks and ores are usually obtainable. Were it possible to make resistivity tests in a laboratory of the drill cores or from pieces of the rocks and ore within an area before attempting a field survey, this would indicate not only the advisability for such a survey but would aid considerably in the interpretation of the results of such a survey. To be of most value a definite method should be used for all such tests, and as yet such a method has not been established.

Jan 1, 1929

Quickly and cheaply consolidate underground slimes to facilitate their use as backfill and permit their easy handling for other reasons. Approach: The slurry containing slimes is pumped into active stopes and electrokinetically dewatered to provide consolidated back fill. How It Works: To densify slimes electro-kinetically two electrodes are placed in the material to be dewatered and densified. Typically, the electrodes are pieces of wire mesh fencing. One is placed on the bottom, and the other is suspended in the slurry near the surface. Figure 1 is a simplified section of a test. A d-c voltage of 100 to 400 volts is applied across the slurry. This causes the solid particles which are in suspension in the water (usually these are negatively charged) to migrate toward the anode; simultaneously, the water moves toward the cathode. Water immediately adjacent to the negatively charged solid particle surfaces contains an excess of dissolved positive ions. When these ions are attracted to the electrode and move towards it, they also exert

Jan 1, 1976

By Earle S. Burnett

This report outlines the experimental procedures for using a Burnett apparatus to obtain compressibility coefficients for multiphase, multicomponent fluid mixtures. The conventional Burnett method is described briefly whereby multiphase compressibility data can be obtained by first determining the compressibility factor, Z, as an isothermal function of pressure alone. Then starting at conditions of temperature and pressure where Z is known, the fluid is cooled at constant volume to some lower temperature at which the resulting pressure is measured, and a corresponding value of Z is obtained from a fundamental relationship between compressibility factors, pressures, and temperatures at constant volume. The isochoric treatment of the fluid, extended to still lower temperatures and along other isochors, eventually results in compressibility determinations for the whole two-phase system thus covered experimentally.

Jan 1, 1963

By L. P. Purtell

The performance of ten anemometers of several types has been measured at low air speeds. Multiple calibration runs provided sufficient data for measuring random error about the mean calibration curve in addition to the difference between indicated and true speeds. Measurements were also performed of the minimum operating speeds of the anemometers.

Jan 1, 1979

By D. A. Hill

This volume contains a summary of the results of past analyses on U.S. Bureau of Mines Contract No. H0122061 which are relevant to electromagnetic location in mine rescue situations. The analytical results indicated that detection of a trapped miner equipped with a special transmitter is feasible in most situations. Location of the miner by surface measurements is also generally feasible within certain errors. The feasibility of miner detection and the accuracy of miner location have been examined theoretically for a wide variety of situations. Agreement with experimental results is generally good in cases where measurements are available.

By M. H. Chetrick

An important factor in the design and operation of a lignite-gasification plant is knowledge of the thermal requirements. These not only vary with different-size plants but also with the operating conditions for a plant of given capacity. Thermal data have been collected since 1945 from a commercial-scale lignite-gasification pilot plant operated by the Bureau of Mines at Grand Forks, N. Dak. The description and operation of this plant and a study of the gas-composition data have already been described in previous reports (1, 2, 3, 4, 5).2) / This investigation was made to review the thermal data taken in tests and to correlate them in terms of the fraction of undecomposed steam and the H2:CO ratio.

Jan 1, 1953

By L. A. Stinnett

An investigation of hazardous surface openings of abandoned and inactive underground mines in the Black Hills area of South Dakota has revealed: (1) tracing legal ownership of mineral claims via county courthouses is confusing, complex, and oftentimes misleading, (2) in general, the selected mine openings in this investigation are to be considered relatively high in risks and hazard potential which poses a threat to the general public, (3) mine closure procedures and designs can generally be categorically implemented depending on the overall situation of the particular mine opening with subsequent unit costs estimates, (4) few preventive state or federal legal measures exist to date concerning mine closures, and (5) liability damages relating to mine opening accidents usually involve expensive and complex common law cases.

Jan 1, 1979

By L. A. Stinnett

An investigation of hazardous surface openings of abandoned and inactive underground mines in the Black Hills area of South Dakota has revealed: (1) tracing legal ownership of mineral claims via county courthouses is confusing, complex, and oftentimes misleading, (2) in general, the selected mine openings in this investigation are to be considered relatively high in risks and hazard potential which poses a threat to the general public, (3) mine closure procedures and designs can generally be categorically implemented depending on the overall situation of the particular mine opening with subsequent unit costs estimates, (4) few preventive state or federal legal measures exist to date concerning mine closures, and (5) liability damages relating to mine opening accidents usually involve expensive and complex common law cases.

Jan 1, 1979

By L. B. Berger, W. P. Yant, R. R. Sayers

"At the request of the Chesapeake & Ohio Railroad Co. a number of tests were made to determine the temperature, humidity, and composition of the atmosphere in certain tunnels of that railroad between Clifton Forge, Va., and Hinton, W. Va. The purpose of these tests was to determine conditions in the cabs of freight locomotives while pulling trains through these tunnels. Tests were made of two types of locomotives, classified by the railroad company as the H-6 and H-7. Both are of the Mallet type, but the H-6 class has one pair of cylinders operating at boiler pressure and the other pair compound, whereas the H-7 operates all four cylinders at boiler pressure, thereby exhausting steam at a higher temperature than the H-6. It was desired to determine the relation between conditions on the H-6 and H-7 engines under comparable conditions of operation. This information supplements previous tests by the Bureau of Mines, discussed in its Reports of Investigations Serial No. 2624, entitled, ""Temperatures in Cabs of Freight Locomotives Passing Through Tunnels of Chesapeake & Ohio Railroad, 11 by s. H. Katz and E. G. Meiter, July, 1924. Three incidental tests of passenger engines were also made."

Feb 1, 1928

By Robert H. Ridgway

Chromite has been produced commercially for slightly more than a century. Developed, at one time, chiefly as a chemical pigment raw material, it has subsequently found extensive application in other chemical industries - as a refractory material for furnace linings and as the sole source of the metal chromium. For some years prior to 1914, its use as a refractory predominated; but post-war development in alloy steels, principally stainless steels, enhanced the metallurgical demand in the form of ferrochrome with a consequent increase in the demand for chromite. More recently direct reduction of chromite in alloy-steel manufacture has been applied to a limited extent. Alloy steels containing varying amounts of chromium, with or without other alloying elements, now find extensive use in a ride variety of ways - in structural material, machines, industrial equipment transportation by land, sea, and air, sanitary equipment, food preservation, and a multitude of other uses. In recent years chromium plating has had wide application and has become important. industrially, but the amount of raw material consumed

Jan 1, 1936

By J. A. Woolf, E. S. Leaver

"So much has been written on the ore genesis of the Comstock Lode that it is sufficient here to describe the original ores as consisting chiefly of quartz and some calcite. In places .a considerable amount of pyrite appears. There are also minor amounts of galena, chalcopyrite, and sphalerite. The chief silver minerals are argentite, stephanite, and polybasite. Most of the gold is native.A composite analysis of the ore; obtained by averaging the results from the early workings of several mines, is shown in Table 1.The history of the milling of Comstock ores from the Sixties to date would call for a review of the development of precious-metal metallurgy. However, a brief outline of the methods employed will give a better basis for studying the difficulties that are to be expected in the final retreatment of the remaining residues.In the earliest days amalgamation was accepted as the main recovery method. The large tonnage of good-grade ore from the Comstock Lode attracted the best metal¬lurgical talent of the time, and developed there the highest skill in the art of amalgamation, including the auxiliary chemical preparation of the ores and the mechanical operation. In this work 0.5 to 6.0 pounds of mercury was used per ton of ore. The mercury loss probably averaged about 2.5 pounds per ton of ore treated.The better grade of tailings from the ores milled were impounded, often near the works. In many cases the same tailings were reworked several times before they entered the main outflow waste stream that had its course down Seven Mile Canyon to the Carson River. Following the water course down the canyon the tailings were re-impounded, and, as metallurgy advanced, new plants were erected to again re-treat them. The most successful of these plants used forms of amalgamation, chlorination, and cyanide methods of recovery. To the tailings from the re-treatment plants, smaller tonnages of untreated tailings produced by milling lower-grade ore are continually added.Along the stream bed down the canyon a series of blanket runways were constructed, and each was independently operated for years by one or more men. All, or the heavier portion of the stream flow was run over the blankets; in this way much of the heavier concentrate, mostly sulphides and mercury products, was reclaimed.All of the residues finally entered the run-off flow along with the sewage from Virginia City and waste from the gas works, saw mills, and stables. As the accumulation along the bed of the Carson River became a nuisance, the lighter and better grade of tailings was impounded on the banks of the river. This accounts for the large dumps locally known as ""Douglas tailings."""

Jul 1, 1928

By Fred N. Kissell

This handbook describes effective methods for the control of methane gas in mines and tunnels. It assumes the reader is familiar with mining. The first chapter covers facts about methane important to mine safety, such as the explosibility of gas mixtures. The second chapter covers methane sampling, which is crucial because many methane explosions have been attributed to sampling deficiencies. Subsequent chapters describe methane control methods for different kinds of mines and mining equipment, primarily for U.S. coal mines. These coal mine chapters include continuous miners and longwalls, including bleeders. Coal seam degasification is covered extensively. Other coal mine chapters deal with methane emission forecasting and predicting the excess gas from troublesome geologic features like faults. Additional coal chapters contain methane controls for shaft sinking and shaft filling, for surface highwall mines, and for coal storage silos. Major coal mine explosion disasters have always involved the combustion of coal dust, originally triggered by methane. Thus, a chapter is included on making coal dust inert so it cannot explode. Methane is surprisingly common in metal and nonmetal mines around the world, as well as in many tunnels as they are excavated. Accordingly, a chapter is included on metal and nonmetal mines and another on tunnels. Proper ventilation plays the major role in keeping mines free of hazardous methane accumulations. The ventilation discussed in this handbook, except for the chapter on bleeder systems, deals only with so-called face ventilation, i.e., ventilation of the immediate working face area, not ventilation of the mine as a whole. The omission of whole-mine ventilation was necessary to keep this handbook to a reasonable size and because a huge amount of excellent information is available on the subject.2

Jan 1, 2006

By P. Bhakta

The U.S. Bureau of Mines developed an alkaline oxidative pretreatment leaching procedure to increase the recovery of gold from arsenopyrite (FeAsS) ores. The best solution compositions for arsenopyrite dissolution were determined using cyclic voltammetry and chronocoulometry. Initial arsenopyrite dissolution occurred at -0.20 V versus standard hydrogen electrode (SHE) in a sodium hydroxide (Na0H) solution. Leaching of a high-grade arsenopyritic ore containing, in percent, 28.2 As, 25.3 Fe, 19.9 total S, and 1.0 Sb and, in troy ounces per short ton, 1.6 Au and 5.5 Ag resulted in >90 pct As extraction at 1000 C, 40 psig O2,4 h, and 2M NaOH solution in a 2-L autoclave. Cyanidation of the leach residues resulted in 90 to 93 pct Au and 60 to 80 pct Ag extractions, compared with only 5 and 15 pct, respectively, without the pretreatment. The procedure was further tested by leaching a low-grade gold ore and a bulk sulfide flotation concentrate prepared from it. Cyanidation of the leach residues resulted in 70 pct Au and 31 pct Ag extraction. The NaOH leachate was partially regenerated by precipitating the arsenate as calcium arsenate [Ca3As04)2] and the sulfate as barium sulfate (BaS04).

Jan 1, 1989

By A. L. Johnson

In this Bureau of Mines report, time-resolved infrared emission spectra and corresponding pressure and temperature histories are reported for large-scale propagations of CH4-air, CH4-air-N2, and CH4-air-CF3Br ignitions in a 12-ft-diam sphere. Absolute spectral radiances were obtained throughout combustion over the 1.6- to 4.8-gym range, and the radiance growth patterns for the H20 (2.5-µm) bands are presented as a function of methane stoichiometry and diluent concentration. Flame temperatures were determined from the C02-band emissions, which approximated unit emissivity shortly after ignition. Burning velocities are also given for some of the test-mixture compositions. Measured flame temperatures were in excellent to fair agreement with theoretical adiabatic values for the CH.-air and CH4-air-N2 mixtures; the best agreement was for the stoichiometric CH4-air mixture. The CH4-air-CF3Br mixtures with =2 pct CF3Br gave poor agreement with theory. The measured temperatures were significantly lower during the early stage of combustion; furthermore, the later stage of combustion was uninhibited and yielded unexpectedly high pressures. Supplemental data from a 2-ft-diam sphere at various initial pressures confirmed that the CF3Br inhibition effectiveness decreases with increased pressure. The possible effects of buoyancy, turbulence, and changing kinetics are discussed.

Jan 1, 1977

By O. C. Blade

Sales of diesel fuel in the United States exceeded 150,000,000 barrels during 1953 and 140,000,000 barrels during 1952. Following are some figures on the distribution of this fuel computed from data issued by the Bureau of Mines. 2/ [ ] Deliveries of diesel type fuel from refineries totaled 91,170,000 barrels during the first six months of 1954, 3/ a corresponding figure for 1953 was 86,284,000 barrels.

Jan 1, 1954