Search Documents

By W. W. Adams

"A recent paper prepared by the writer summarized the results of an analysis of the accident records of 34 metal mines for the calendar year 1925. The present paper summarizes the results of a similar analysis of the accident records of 59 coal mines for the same year. This summary is based upon reports furnished to the Bureau of Mines, Department of Commerce, by operating companies that par¬ticipated in the National Safety Competition of 1925.The purpose of the Competition was to establish the lowest accident-severity rate, thus showing the smallest loss of time from accidents in proportion to total number of man-hours worked. The reports covered all lost-time accidents that occurred during the year, that is, all accidents that disabled an employee beyond the day or shift on which the accident occurred. Detailed information for each of the 59 coal mines is given in the appended table. Each mine employed at least fifty men underground; over half of than employed more than 200 men underground. Hence the accident records should be typical of those of large-scale mining operations in general where the company is devoting special attention to accident-prevention work. The mines covered by the reports are situated in eleven States: Alabama, Illinois, Indiana, Kentucky, Maryland, Ohio, Pennsylvania, Tennessee, Utah, Washington, and West Virginia.A tabulation of the reports covering the 59 mines showed an accident-frequency rate of 123 per million hours of ""exposure* and an accident-severity rate of 10.214 per thousand hours of exposure3. The total volume of exposure or employment was 29,117,561 hours, representing the equivalent of work of 12,000 men for three hundred 8-hour shifts. The records covered employment and accident above ground as well as underground, although they did not include stripping or open-pit mining. Accidents during the year resulted in 33 deaths, 1 permanent total disability, 28 permanent partial disabilities, and 3,510 temporary injuries. These accidents represented a loss of tine equal to 297,417 man days. In arriving at this lost-time equivalent, each fatality and permanent total disability was weighted at 6,000 lost days (see footnote 3), as specified in the scale adopted by the International Association of Industrial Accident Boards and Commissions; permanent partial disabilities were weighted according to nature of injury, in accordance with the scale adopted by the :Board; temporary injuries were weighted according to the actual number of calendar days during which the employee was incapacitated as a result of the injury."

Nov 1, 1926

By John J. Mulligan

Since 1941 the Federal Bureau of Mines has been conducting an intermit-tent program of placer and lode investigations to evaluate the potential tin resources of the western Seward Peninsula tin belt. Previous investigations were made in the Potato, Cape, Brooks (Lost River), and Ear Mountain areas. As part of this program the Bureau made a reconnaissance of reportedly tin-bearing stream gravels in areas adjacent to the previously worked tin deposits at Lost River and Potato Mountain. The objective of the reconnaissance was to determine if additional areas might be favorable for lode or placer exploration. The work was begun late in the fall of 1956 and completed during the following summer. The streams sampled were the Lost River and York Creek in the Brooks Mountain area and the Anikovik River and Kigezruk and Baituk Creeks in the York area. Samples were obtained by churn-drilling methods employing conventional placer-evaluation procedures. Holes were drilled at wide intervals at sites chosen as being representative of drainage areas rather than of individual gravel deposits. Minor to trace amounts of tin were found in the gravels of all these streams, but the highest grade was 0.35 pound of tin per cubic yard in the gravels of Lost River below the mouth of Tin Creek. Small amounts of gold were found on Baituk Creek and in one hole on the Anikovik River; the highest grade did not exceed 10 cents per cubic yard. Traces of scheelite and barite were found on York Creek, chromite was encountered in one hole on the Anikovik River, and minor amounts of titanium minerals (probably derived from basaltic intrusives) were found in the York area.

Jan 1, 1959

By Guy E. Dent, Hugo E. Kuehn

"SUMMARYFor making a comparison of magnetic surveys measured from the ground and from the air, Worcester County, Maryland, was chosen as a proving ground. Vertical magnetic intensities were observed on the ground, and total magnetic intensities were observed from the air. A comparison of the two magnetic maps reveals similar large magnetic features, but these are displaced in some instances by distances greater than a mile. Magnetic terrane in the two charts is of the same type but often differs greatly in respective characteristic features.The sacrifices in accuracy that may be expected from the use of different systems of diurnal magnetic corrections on ground observations constitute a part of this report.INTRODUCTIONThe value of magnetic surveys for gaining information concerning the crystalline basement is recognized increasingly. That this topography is often reflected to a major degree in the overlying sediments with certain offsetting is well understood. Even where such sediments are deep, the surface topography of upper formations often reflects this bedrock topography to a certain degree."

May 1, 1947

By T. E. Gray

This report describes the preparation characteristics of the signifi¬cant coalbeds in Preston County, W. Va. It is one in a series of reports planned to determine coals suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 2 million tons of coal was produced in Preston County, W. Va. in 190, none of which was cleaned mechanically. Estimates as of January 1, 1959, indicate that more than 3 billion tons of coal remained in the county in beds 12 inches or more thick. The Bakerstown, Mahoning, Upper Freeport, and Upper Kittanning beds were selected by the Bureau of Mines for study based on current production and estimated minable reserves. Sample locations were selected after study of the literature, conferences with mining engineers and mining company offi¬cials in the field, and examination of available sites. Four samples were collected from the Bakerstown and Upper Freeport beds and one each from the Mahoning and Upper Kittanning beds.

Jan 1, 1961

By T. F. Mitchell, J. A. McAllister, S. J. Hussey

"INTRODUCTION During the Bureau's extensive program of investigating possible domestic sources of manganese, an are-dressing study was conducted in its laboratories at Salt Lake City, Utah, on a sample of oxide manganese ore representative of vein material from the Ophir Hill mine at Ophir, Tooele County, Utah. The sample (obtained by blasting down and mixing a portion of the vein) was submitted by the Ophir Development Co. of Ophir, Utah. As the ore was too law in grade to be acceptable for direct production of ferromanganese, it was tested to determine its amenability to concentration by ore-dressing methods.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to Metals Reserve Company was ferrograde manganese, grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., 0.18 percent; A1203, max., 6 percent; Zn, max., 1 percent.Later, the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.0 percent iron, and 11 percent silica plus alumina. Premium were paid for manganese content in excess of, 48 percent and iron content below 6 percent, penalties being imposed upon products containing less than 48 percent manganese or more than 6 percent iron or more than 11 percent silica plus alumina. The specifications for commercial manganese further required that maximum particle size be 12 inches and that 75 percent of the product be coarser than 20-mesh. Therefore, fine material, such as table and flotation concentrates, had to be nodulized or sintered. In addition, carbonate manganese ores were not acceptable unless calcined."

Oct 1, 1947

By James S. Browning

The Bureau of Mines conducted laboratory batch and small-scale continuous flotation tests of weathered mica pegmatite ores from Alabama and North Carolina to determine the technical feasibility of recovering commercial-grade mica concentrates. A new anionic-catonic method was developed for recovering mica in the presence of clay slimes. In continuous tests, concentrates containing 98.1 percent mica were obtained from the Alabama pegmatite ore; the North Carolina pegmatite ore concentrates contained 97.2 percent mica. The recoveries were 83.8 and 81.6 percent, respectively.

Jan 1, 1965

By Nabil A. Bibawy

An improved method for preparing gravimetric standard gas mixtures of helium-4 in nitrogen has been developed by the U.S. Bureau of Mines. A single-pan 12-kg analytical balance that has a sensitivity of 3 mg is used to prepare the mixture. The balance will accommodate a cylinder having a volume of approximately 4 L that weighs approximately 5 kg. The method has been improved to a precision of ±O.04 pct by performing four successive dilutions, by improved handling of gases in the manifold, and by using an improved analytical method to select high-purity gases.

Jan 1, 1990

By Robert J. Evans

The Hopper-Feeder-Bolter (HFB) is a prototype multifunctional machine designed to improve productivity by minimizing continuous miner place changes. It is designed primarily to work beside a two-pass continuous miner, bolting on one side and then place changing to bolt the other side while simultaneously providing a surge car and lump breaker located directly behind the continuous miner. Surface testing was conducted at the Bureau of Mines Mine Equipment Test Facility (METF) to evaluate overall system performance and reliability. Tests were conducted to evaluate place changing, tramming, lump breaking, roof bolting, drawbar pull, conveying, temporary roof-support (TRS) capacity, lighting, and noise. Surface test results indicate the HFB is ready to be tested and evaluated underground in a production mode.

Jan 1, 1988

By Harold E. Marr

The Bureau of Mines evaluated two drill-hole probes for the delineation of Missouri lead ores. The battery-powered, portable instruments, weighing less than 30 pounds, were designed for logging holes of 1.8 inches in diameter or larger. These probes have dual scintillation detectors, balanced filters with a pass band for lead Ka radiation, and a cobalt-57 source of radiation. The results of field tests in Missouri confirm laboratory tests indicating that probe response can be correlated to lead ore grade using counting times of 10 seconds or less at any selected depth in the hole.

Jan 1, 1972

By H. C. Carpenter

Lignite tar made by low-temperature Lurgi-Spülgas carbonization of North Dakota lignite was hydrocracked in single-pass, fixed-bed operation at 3,000 pounds per square inch over cobalt molybdate catalyst to produce gasoline, and at the same pressure, over zinc chromite catalyst to crack the high-boiling phenolic compounds to low-boiling phenolics. Hydrocracking the raw tar or the creosote-oil fraction from the tar over cobalt molybdate removed most of the oxygen, sulfur, and nitrogen in the forms of water, hydrogen sulfide, and ammonia, and produced gasoline yields from 31 to 59 volume-percent. The gasoline fractions contained from 0.1 to 7.7 volume-percent tar acids, but tar-base percentages were too low for reliable measurement; removal of these materials with dilute caustic and acid solutions also reduced the sulfur and nitrogen to 0.01 weight-percent or less.

Jan 1, 1963

By Robert W. Smith

The Bureau of Mines is engaged in a systematic evaluation of the thermodynamic properties of combustion gases. These studies are designed to provide basic thermodynamic information of high accuracy, facilitating the theoretical study of flame and combustion phenomena. This report is the fourth of a series4/ presenting results of the study for particular fuel-oxidant systems. These calculations have as their objective the evaluation of the constant pressure flame temperatures of methane-air, propane-air, and ethylene-air mixtures for a range of pressures.

Jan 1, 1953

By R. K. Koch

The Bureau of Mines produced several series of titanium castings in order to investigate the feasibility of producing commercial-grade titanium castings in bentonite-bonded olivine or zircon sand molds. The use of these molds for titanium casting was investigated as a possible alternative to the industrially used rammed graphite process. Parameters investigated were mold mixtures, mulling, gating, venting, drying, and mold washing. The investigators found that castings with superior ductility and fatigue life, compared with rammed graphite castings, could be made by fume-free pro-cesses in molds bonded by western bentonite, using either olivine or zircon sand. Zircon molds were satisfactory for both light-and heavy-sectioned castings. However, olivine molds were suitable only for light-sectioned castings because the mold-metal reaction became excessive during the pouring of heavy-sectioned castings.

Jan 1, 1981

By F. R. Cattoir, R. E. Cumings

Columbium metal was electrorefined in a fused - salt electrolyte . Excellent results were obtained in lowering the impurity content in a 94 - percent columbium anode feed material to produce a 99.8- percent - pure metal . The reductions of the major impurities follow : Oxygen from 19,800 to 500 ppm , carbon from 9,700 to 25 ppm , iron from 9,200 to 630 ppm , nitrogen from 2,100 to 90 ppm , and silicon from 750 ppm to not detected . Columbium with a purity of 99.9 percent was produced from 99.5- and 99.8 - percent grades of columbium. The investigation was devoted to the evaluation of a fused - fluoride - salt electrolyte ( KF - NaF- K₂ CbF, ) for electrorefining columbium. The effects of the columbium concentration and the voltage upon the product's purity were investigated . The effect on the cathode current efficiency of ampere - hours of deposition and the formation of a dual valence state of the columbium was also investigated .

Jan 1, 1964

By Andrew Allan

[Research conducted by the Bureau of Mines hrinq the last 5 years on the uce of machines for 7!naer:rolmrl ?.eve loym~nt in pi.t,c hlng anthracite beds l~a~ provide? data ?howin? that ?:;panrt of thc roof an9 str?eg of thes? oTen - jnqs requires almst half of' the PRS? workin? time. The possibilitie~ of i!rinz a mvable,. te1.ee*co@. c tpr? 3f ?tee1 ~h-!.oltl at the face in~tetcrl of conventional wood a*ti~yorts w?r? si:~q~eteil by engineers engaqad on the~ work If ~uch a shi~l8 COLI.~,~. be ~sve~.~yad, it tnillil man that face workera w~uld be provi8ed with mulrnu.m prot?ct+on from falls of' roof and ribs mi! the en- tire ehift could he I~W? Lo ~lro,J.~:ce cocl. Fermanent tim3er coald be p'l.acnA behind the shielR independently of the 'face work as the face advanced.]

Jan 1, 1953

By Paul M. Tyler

This paper is one of a series of digests of foreign mining legislation and court decisions prepared in advance of a general report relative to the right of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Yugoslavia was prepared from information furnished by John Dyneley Prince, American Minis- ter at Belgrade, in response to a questionnaire submitted by the Bureau of Kinos and transmitted through the courtesy of the Department of State.

Oct 1, 1929

By Martin A. Elliott

The Bureau of Mines began its investigation of the use of Diesel engines underground to provide technical information necessary to assist this development in the United States. It was considered desirable to furnish such assistance because successful European developments/ in this. field had indicated that Diesel mine locomotives might be safer than electric trolley locomotives. The Bureau has recognized for some time the importance of eliminating the hazards associated with underground haulage systems using bare trolley wires. For example, each year 30 to 40 fatalities occur as a result of electrocution by contact with bare trolley wires. In 1943 and 1944, 101 men were killed and extensive property damage occurred as a result of mine fires started by falls of roof grounding the bare trolley wires.

Jan 1, 1948

By David P. Lindroth

The objective of this research by the Bureau of Mines was to determine the technical feasibility and associated pilot data for drying minus 1/4-in coal with microwave energy at a frequency of 2.45 GHz. The drying data were obtained experimentally on three coal types: bituminous, subbituminous, and lignite. The experiments were performed with a custom-designed conveyorized microwave oven having a continuous power capability of 12 kW. Drying efficiencies near the theoretical maximum of 1.54 kg of water per kilowatt hour of energy input were achieved for two coals and two sizes; overall drying efficiencies averaged 77 pct.

Jan 1, 1986

By Thomas M. Barczak

This Bureau of Mines report investigates shield mechanics by describing the elastic response and interaction of shield components to applied vertical and horizontal displacements for various canopy and base contact configurations. This research provides information on generalized shield mechanics, which is applicable in describing the behavior of all two-leg shield supports. Utilizing mechanics of materials concepts and known kinematic relationships for two-leg shield supports, free-body diagrams are constructed for each shield component illustrating internal axial, shear, and bending moment responses required to maintain equilibrium for each load case evaluated. Predicted shield (component) responses are verified by controlled displacement of instrumented longwall shields in the Bureau's mine roof simulator (MRS). Conclusions drawn from these analyses include shield structural responses are significantly dependent upon canopy and base contact configurations. Applied displacements also significantly affect shield responses. Horizontal displacement produces different responses than those produced by vertical displacements. The direction of horizontal displacement is also significant in evaluating shield response. Applications of shield mechanics to in situ support monitoring are also discussed. An objective of this research program is to establish unique shield responses to identify in situ load conditions.

Jan 1, 1989

By A. L. Engel

This investigation was undertaken to assess the feasibility of processing an extensive deposit of iron ore near Palisades, Eureka County, Nev., previously penalized for high phosphorus content. The experiments described indicate a satisfactory accomplishment of objective. Chemical treatment will permit a high-phosphorus iron ore to be used. Leaching with acid solution effectively lowers the phosphorus content with a [gligible] loss of iron. The use of hydrochloric acid is preferred because [ ] does not contaminate the ore and the cost is lower. Minus-1/2-inch ore was satisfactorily leached in 24 hours, minus-1/4-inch ore, in 8 hours, and minus-10-mesh ore, in 3 hours. About 40 pounds of acid per ton of ore was consumed in each instance.

Jan 1, 1959

By George T. Faust

The petrographic microscope plays an important role in the mineral dressing of nonmetallic materials. Petrographers and mineral technologists have evinced an interest in the technique developed, specifically, for mineral-dressing problems. The following dissertation makes the informa¬tion more generally available. ACKNOWLEDGMENTS The authors are indebted to O. C. Ralston, chief engineer, Nonmetals Division, and to Will H. Coghill, supervising engineer of the Southern Experiment Station for a critical reading of the manuscript. They are also indebted to their colleagues for technical information obtained in the course of cooperative work, in particular to J. B. Clemmer for the use of the data on fluorite.

Jan 1, 1940