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By D. K. Deardorff

The purpose of this work was to investigate the hafnium-carbon phase diagram. Alloys used to study this system were prepared from high-purity components by both consumable-and nonconsumable-electrode arc melting. Data for the diagram were obtained on the alloys by metallography, optical pyrometry, thermal analysis, heat treatment, and X-ray diffraction. The data indicate that a carbide compound occurs over considerable range of composition, and that one of each of the following types of reactions occurs in the hafnium-carbon system: Peritectoid, peritectic, and eutectic. The maximum melting temperature of hafnium carbide is 3,840° C at 49 to 50 atomic percent carbon, and the composition range of hafnium carbide at temperatures of 2,150° to 2,380° C is from 37.0 to 48.5 atomic percent carbon. The hafnium a-S transformation temperature is raised on alloying with carbon from 1,750° to 1,890° C, where a peritectoid reaction isotherm occurs. Alloying hafnium with carbon increases the hafnium melting temperature from 2,190° to 2,250° C, at which temperature a peritectic reaction occurs. Hafnium carbide and carbon react at 3,055° C to form a eutectic of 68.3 atomic percent carbon.

Jan 1, 1967

By Charles G. Howard

Accidents involving underground rail transport were analyzed to quantify the magnitude and the operational requirements for individual mine car braking systems. The results showed that the brake preventable accidents represent only 2% of the total underground fatal accidents and less than 1% of the total underground nonfatal accidents. In addition, the brake preventable accidents are expected to decline over the next decade. The costs of accidents involving deaths and Injuries were determined using various well accepted methods. The costs of a brake retrofit program for all operating underground coal cars were developed separately for small and large coal mines. Costs of retrofit brakes, new car brakes, maintenance, inspection and repair facilities were included in the esimates. The analysis showed that a retrofit program would not significantly increase safety, and that the program cost would greatly exceed the corresponding expected benefits.

Jan 1, 1979

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

By H. W. Sheffer

Technical and economic aspects of community refuse disposal systems and their effects on the environment are identified and described. Seven landfills and two incineration systems, located throughout the United States, are reviewed.

Jan 1, 1971

By G. W. Murrie

A geologic study of the Mary Lee Group of coalbeds in the Black Warrior coal basin was undertaken to examine coal stratigraphy and determine regional trends and extent of the coalbeds. The area investigated encompasses 835 square miles in Jefferson, Walker, and Tuscaloosa Counties, Ala. More than 700 core logs were used to construct a structure map, coal, interval, and overburden isopachs, and cross sections. There is evidence that structure affected sedimentation. Coalbed isopachs indicate the Mary Lee Group was deposited in fluvial-deltaic and low-lying coastal plain environments. The Mary Lee coalbed is the only coalbed which is continuous throughout the area, commonly with two benches which have a combined thickness of 2 to 12 feet. The Mary Lee coalbed changes rank in the basin from high-through medium-to low-volatile coal. The methane gas potential of the Mary Lee Group coals is estimated to be greater than 1 trillion cubic feet. There is an excellent correlation between the orientation of surface cleats with those measured underground in the Mary Lee coalbed. The face cleats roughly parallel the axes of the area's folds and trend northeast-southwest.

Jan 1, 1976

By W. A. Grosh

Records show that much of the lead produced in the Upper Mississippi Valley lead-zinc field was taken from natural openings along crevice systems at shallow horizons or at the surface. During the early history of the district, the shallow deposits were worked intensively; but in recent years the production of lead, except as a byproduct of deeper mining for zinc ores, has not been significant. Considering the methods of early mining, the character of mineralization, and the fact that galena can still be found on the surface of the old digging areas, it was reasoned that enough mineralization might remain on and above bedrock to permit, through the use of modern equipment and methods, economical re-treatment of surface material in the digging areas.

Jan 1, 1960

By E. L. Litchfield

Four short-term studies of practical ignition problems were undertaken and completed during the course of the Bureau of Mines project "Development of Specifications for Intrinsically Safe Equipment." Conclusions were as follows: (1) the most easily ignitible mixture of propane-air in a PTB break flash apparatus is approximately 5.2 percent propane; (2) miniature lamp bulbs to be used in intrinsically safe circuits are about as incendive to coal dust-air as to methane-air and should be tested in gas mixtures containing about 7.0 to 7.5 percent methane; (3) the sodium amalgam contained in high-pressure sodium lamps does not present an ignition hazard for coal dust or methane, where the lamps contain no more than 30 milligrams of amal-gam; (4) the maximum allowable surface temperature of permissible electrical enclosures should remain at 150° C despite efforts by industry groups to raise the value to 200° C.

Jan 1, 1980

By W. F. Wyman, S. F. Ravitz

"INTRODUCTION By far the greater part of the high-grade manganese ore used in the United States is imported from overseas. During the early part of the recent World War importations of manganese ore were seriously threated, and it appeared that it would be necessary to utilize low-grade domestic ores to the fullest possible extent. Among the processes that appeared to offer the best possibilities for beneficating low-grade domestic oxide manganese ores, which ordinarily are net readily amenable concentration by ore-dressing methods, were those involving leaching with sulfur dioxide. The Bureau of Mines therefore investigated the amenability of a large number of such ores to sulfur dioxide leaching.Several sulfur dioxide processes for beneficiating low-grade oxide manganese ores have been proposed. 3/ One of these, based on a patent by Van Arsdale and Maier, 4/ was used recently in a plant constructed to treat 1,000 tons per day of 20-percent manganese ore from the Three Kids deposit near Las Vegas, Nev. 5/ In this process the ore slurry is leached with sulfur dioxide gas, the resulting solution is evaporated to crystallize the manganese sulfate, the crystals are decomposed thermally to produce high-grade manganese oxide and regenerate sulfur dioxide, and the manganese oxide product is nodulized. The Bureau of Mines has recently developed a process 6/ in which a suspension of the ore in calcium dithionate solution is leached with dilute S02 gas, the manganese is recovered from the resulting solution by a simple lime precipitation, and the precipitate is nodulized or sintered to form a high-grade manga¬nese oxide product."

Jun 1, 1947

By W. N. Patterson

The three major objectives of this contract were (1) to survey underground diesel-powered mining machinery to determine noise exposure problems, (2) to recommend noise control techniques, and (3) to develop a technique for predicting underground sound levels from surface sound power measurements. The objectives were achieved. The contractor developed information on the severity of the noise problem caused by diesel engines underground and pinpointed the equipment causing the problems. He recommended a number of corrective techniques that can provide relief until long-term solutions are found. A procedure for predicting underground noise levels from above-ground measurements of the machine noise was found valid for several cases tested.

Jan 1, 1975

By S. McGinn

The Brunswick Mine Diesel Particulate Filter Study was one of several research projects initiated by the Diesel Emissions Evaluation Program (DEEP). The study was carried out at Noranda?s Brunswick Mine in Bathurst, New Brunswick by Noranda Technology Centre and Brunswick Mine personnel with the collaboration of Natural Resources Canada - Canada Centre for Minerals and Energy Technology (CANMET), National Institute of Occupational Safety and Health (NIOSH), Andreas Mayer of VERT, and diesel particulate filter (DPF) system suppliers. The study began in early 2000. Field evaluations continued for 20 months. The final report?authored by Sean McGinn?was submitted to DEEP in the Autumn of 2003.

Jan 1, 2004

By Edward L. McHugh

The appraisal of mineral resources of the Challis National Forest, Idaho, by the U.S. Bureau of Mines, was made so that the mineral resources of the forest could be appropriately considered in land use planning. Information from this study is intended to help the U.S. Forest Service to incorporate mineral resource data into forest plans. The study was done in conjunction with the U.S. Geological Survey, which released a companion report on the geology and mineral potential of the Challis National Forest in 1989. Mineral development activity in and under the Challis National Forest has been of great economic significance to Idaho and the United States. Since the 1960's, mines within the forest have produced mineral commodities worth more than $590 million A current (1989) commodity prices. Identified mineral resources have a gross value of about $2 billion at current prices, including 8 strategic or critical minerals. The U.S. Bureau of Mines study identified and described 723 active and inactive mineral properties within the forest. Mineral properties with identified resources were evaluated to determine their economic significance, and an assessment was made of the feasibility of mineral development. Of the 2,516,191 acres in the Challis National Forest, about 390,000 acres were classified as having mining development interest commercially important mineral production, mainly of molybdenum, gold, and silver from the Challis National Forest is likely for the foreseeable future.

Jan 1, 1991

These proceedings consist of papers presented at two Bureau of Mines Technology Transfer Seminars in early 1980 for the purpose of disseminating recent advances in mining technology related to surface coal mining reclamation.

Jan 1, 1980

By Catherine C. Kilgore

The Bureau of Mines investigated the availability of lead and zinc from 104 domestic mines and deposits. Fourteen primary lead and fifty-three primary zinc operations with in situ demonstrated resources containing 27.3 million metric tons (t) of lead and 53 million t of zinc were subsequently evaluated. Potentially 17.5 million t of lead and 2.4 million t of byproduct zinc could be recovered from 14 primary lead operations. Economic evaluations performed in constant January 1982 dollars determined a long-run total cost per pound of recoverable commodity. Including a 15-pct discounted-cash-flow rate of return (DCFROR), 59 pct of primary lead was potentially available at or below $0.32 per pound of lead. Potentially 40 million t of zinc and 5.6 million t of byproduct lead could be recovered from 53 primary zinc operations. Ninety percent of the recoverable zinc is potentially available from currently nonproducing mines and deposits, and a weighted average of their long-run total costs was determined at $0.98 per pound of zinc. At a breakeven (0-pct) DCFROR, these non producing operations had a weighted average long-run total cost of $0.58 per pound of zinc. Sensitivity analyses illustrated that operations that recover byproducts were most sensitive to fluctuating metal prices, producing operations were more sensitive to increased smelter treatment charges, and nonproducing operations were impacted most by the DCFROR.

Jan 1, 1983

By H. B. Brunot, L. C. IlsLey, E. J. Gleim

"INTRODUCTION To supply inspectors, safety engineers, and others with detailed information as to the safety features of the various electrically operated machines that have been approved as permissible by the Bureau of Mines, three bulletins and five reports of investigations have been published dealing with the various classes of approved machines:Bull. 313, Permissible Storage-Battery Locomotives and Power Trucks.Bull, 343, Permissible Coal-Handling Equipment Approved from January 1926 to December 1930, inclusive.Bull. 382, Permissible Coal-Cutting Equipment Approved Prior to July 1, 1932.Rep. of Investigations 3309, Permissible Electrically Operated. Air Compressors.Rep. of Investigations 3326, Permissible Electrically Operated Room Hoists.Rep. of Investigations 3345, Permissible Electrically Operated Rock-Dust Distributors.Rep. of Investigations 3363, Permissible Electrically Operated Hand-Held Coal Drills.Rep. of Investigations 3391, Permissible Electrically Operated Post Drills and Drilling Machines.The present paper gives similar information relative to the mine pumps approved before October 1, 1939."

Mar 1, 1940

By Philip C. Good

Preliminary studies showed that direct hydrolysis of H2SiF6 to SiO2 and HF at elevated temperatures was subject to many mechanical difficulties, and that corrosion of construction materials was a serious problem. Elimination of SiO2 from the HF product was generally poor. An alternative procedure, hydrolysis of lime-neutralized H2SiF6 by steam at 950° to 1,100° C, yielded a product very low in SiO2. Condensates containing up to 300 g/1 HF were prepared.

Jan 1, 1968

By Theodore L. Turner, Joseph H. Swift

A study on a small laboratory scale was made of the use of ammoniacalammonium carbonate for batch leaching Mn from low- grade manganiferous materials ( 6 to 16 pct Mn) obtained from deposits in the southern district of Aroostook County , Maine . These materials were partially reduced at 500 ° to 700 ° C with H₂ or CO and then leached with solutions of NH and CO₂ dissolved in water . Extraction of 80 to 90 pct of the Mn was obtained from some sample materials , but 10 to 34 pct of the iron was also extracted . Material from the Littleton Ridge deposit contained manganese intimately associated with Fe , a condition which contributed to difficulties in obtaining a commercially acceptable product . Extensive investigations of the leach and reduction processes with various mixtures of H₂ and water vapor , and CO and CO₂ , failed to disclose a set of conditions for selectively leaching the manganese . Finely divided metallic Fe was probably produced during the reduction steps so that Fe was leached with the Mn in the subsequent extractions .

Jan 1, 1964

By S. L. Windes

"INTRODUCTION For a number of years, the Bureau of Mines conducted tests on various types of structures to ascertain the effect of seismic vibrations emanating from quarry blasting in an effort to determine an index of damage. Associat¬ed with these tests, occasional records were made of the characteristics of the air blast or concussion from the explosions. Although the importance of the air-blast problem was recognized, the equipment was not designed for airblast measurements, nor was the early research program concerned with the problem. After the ground-vibration tests had been completed, attention was turned to study of the air blast and its effect. The program was modified, however, in certain aspects by the imminence of war and the final entry of the United States into the conflict. These modifications were made to supply information pertaining to military and civilian defense problems.Detailed discussion of these problems is beyond the scope of this report, which attempts to present preliminary results of factual and fundamental character. However, it may be noted that airblast data are urgently needed for intelligent design of both Government and non-Government buildings, which must withstand the air blast from bombs and afford maximum protection for the occupants. The safety of vital equipment above and below ground necessitates consideration of damage from air blast. Protection against use of dynamite by saboteurs, moreover, hinges largely on the effect of air blast. Identification of a planned ""accident"" involving dynamite often entails knowledge of the characteristics and power of the airblast.The peacetime problem of damage from air blast resulting from quarry and mining blasting activities is of course exaggerated by the wartime requirements of increased production accelerated operation, and enlarged development."

Jun 1, 1943

By T. M. Barczak

One of the primary goals of Bureau of Mines research is to reduce the cost of coal mining by improving the efficiency of longwall supports. One method of achieving this goal is the optimization of stress distribution within the support structure, resulting in a lower overall weight, more fully stressed shield. However, before stress optimization can be initiated, load conditions must be defined that cause maximum stress in the various support components. A finite-element model of a longwall shield was used to identify these critical load conditions. These load conditions were then evaluated in the Bureau's mine roof simulator (MRS) by instrumentation of a longwall shield and measurement of strains in each of the shield components. The critical (canopy-base contact) load conditions were identified that can cause structural failure at less than rated shield (hydraulic yield) capacity. Comparisons were made between full-contact and partial-contact load conditions. Other parameters investigated included the stiffness of the contact material, changes in shield geometry, rate of load application, and effects of horizontal constraint. Conclusions were drawn regarding the structural integrity of the major shield components and potential for stress optimization.

Jan 1, 1987

By J. W. Eckerd

This report describes an investigation of the technical feasibility of using a conventional commercial-size (10-ft. i.d.), rotating grate, dry-ash-removal type gas producer to make producer gas from chestnut-size bone anthracite. Test instruments were installed, and some minor changes were made in the equipment to handle the large quantities of materials expected. Extensive tests, lasting about 4 weeks, were planned, using 35 to 50 percent ash chestnut anthracite bone. However, operations were suspended after 8 days when it became apparent that to use this type of fuel satisfactorily substantial changes in equipment and operating procedures would be required. Nevertheless, enough data were obtained to indicate that gas could be produced continuously and routinely from bone coal in this type of producer whenever conditions justified the necessary development work.

Jan 1, 1960

By Leo J. Neill, O&apos

Abrasives are essential to the manufacture of munitions - airplanes, gas, shells, tanks, and in fact every product that involves metal forming or finishing. An indication of the importance of abrasives in the national defense and aid-to-Britain programs is the close peace-time correlation between demand for abrasives and automobile production, which in recent years has consumed more than 35 percent of the total output of abrasives. Unprecedented demands on the abrasives industry are forecast by the rapid expansion in airplane output, tie increased mechanization of all armed forces, and the consequent speeding up not only of the factories where finished munitions are made but also of the steel mills and other factories were additional large quantities of abrasives are needed for snagging or rough-grinding semifinished products before they can be used by the fabricators. A recent survey by the artificial abrasives manufacturers indicates that they can readily increase their output 75 percent compared with the previous peak of 1937 without building new plants. By overhauling production schedules, their maximum production possible could be increased to 182 percent of the 1937 output, and the nature of the industry is such that plant capacity could be increased rapidly if need therefor should arise. No figures on the estimated requirements for abrasives in 1941 or 1942 have as yet been compiled, but the industry feels that it can meet demands as they develop.

Jan 1, 1941