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By Raymond M. Kacmar

This report presents the Bureau of Mines research on the hardware reliability prediction for two Bureau monitoring projects. The basic concepts of reliability predictions are introduced along with the reliability models and assumptions used for this particular evaluation. The results of the reliability predictions are for ground-fixed and naval-sheltered environments.

Jan 1, 1986

By B. T. Brady

Laboratory measurements by the Bureau of Mines indicate that failure in dry rock specimens measuring approximately 13 cm in length is preceded by tilt anomalies lasting a few milliseconds. The tilt behavior is qualitatively similar to that reported to precede earthquakes. Test results suggest that the time duration of this tilt anomaly for laboratory specimens of this length is independent of rock type, in agreement with theoretical predictions and other experimental data on rock failures including earthquakes.

Jan 1, 1975

By H. G. Lucas

A feeder screw supplied at constant pressure by a hopper-orifice arrangement was developed for feeding solids in size ranges up to several hundred micrometers at constant flow rates. Performance of the feeder was evaluated by measuring the flow rates obtained with 3-to 7-micrometer coal ash, 70 percent through 200-mesh coal, and minus 325-plus 400-mesh coal ash. Constant feed rates within a few percent of set values were achieved for half-hour periods for the larger particles and for 5-minute periods for the finer particles. Suggestions are given for feedstock preparation and feeder operation for optimum performance.

Jan 1, 1974

By J. A. Rowland

Manganese-copper alloys containing 60 percent or more electrolytic manganese exhibit an unusual combination of high vibration damping capacity with good strength properties. Properties of the pure alloys were first studied in the laboratories of the Federal Bureau of Mines and have been described in a series of technical papers1/ published from 1941-49. The unusual characteristics of these manganese-copper alloys attracted the attention of research metallurgists and several additional investigations have also been reported in the literature.2/ The engineer, also, was attracted by the combination of high strength and high vibrational damping capacity possessed by these alloys. A wide field of application in structural and machine design was obvious. However, serious difficulties encountered in commercial fabrication of structural or machine components from the alloys retarded attempts at their practical utilization. For this reason the Federal Bureau of Mines, in cooperation with the United States Navy, Bureau of Ships, undertook a program designed to develop practical methods for fabricating a selected group of the high-damping alloys. It is the purpose of this paper to summarize a part of that investigation in a form suitable for use by the metallurgist interested in commercial fabrication of the alloys.

Jan 1, 1955

By John R. Bartels, Dean H. Ambrose, Richard C. Wang

This paper presents the results of a study to verify and validate a computer model that represents and analyzes motions and hazardous events in a simulated three dimensional workplace. The purpose of the computer model is to support research that is investigating the safe speed range for the vertical movement of roof bolter boom arms to reduce worker injuries in underground coal mines. The information obtained for this paper is based upon a project that is investigating means to reduce workers risks of injury from exposure to mining machinery. The methodology being employed by the project includes human factors design considerations, anthropometric modeling and simulation tools, laboratory validation, engineering interventions, and collaboration with industry and an equipment manufacturer. The results of this study were used to (1) determine the input parameters that are unique to the mining environment and needed to develop a credible, computer-based, human-machine interactive model, (2) develop test methods to measure the required parameters, and (3) to refine the human-machine interactive computer model.

By Fred N. Kissell

The new MSHA diesel rules have stone mine operators looking hard at pos¬sible upgrades to their ventilation systems. There are existing methods to reduce diesel engine emissions (MSHA, 2001)(Head, 2001b),but many operators will decide that a ventilation upgrade is necessary is well. NIOSH hay several stone mine ventilation projects underway, but in the meantime a good information resource is the work done by the U.S. Bureau of Mines in the 70's and 80's on ventilation for oil shale mines. The Bureau conducted this research because oil shale mines were projected to be gassy and would, therefore, require a lot of ventilation air. The focus of this oil shale work was on the use of jet tans for lace area ventilation, and on stoppings that would he low Lost and leak-tight. The work also considered changes in mine design to reduce the number and size of stoppings. The findings are still applica¬ble to stone mines.

Jan 1, 2002

By Ivette E. Torres

The estimated value of world crude mineral production in 1992 was $1,633.3 billion in terms of current (1992) dollars, or $1,178.0 billion in terms of constant 1983 dollars. This latter figure was 4.8% above the 1992 level but was 2.4% below the record-high level of $1,207.1 billion 1983 dollars set in 1980. Table 1 provides the latest available revised time series of the estimated value of world crude mineral production both in terms of 1983 constant dollars and in terms of current dollars. The statistical base for this estimation is derived from the data on the value of production of a group of key commodities that was published in the authoritative French language mineral industry periodical, Annales des Mines, for selected years up to 1983. The aforementioned values and those presented in the table are for crude minerals only and only begin to suggest the impact that the mineral industry has on the world economy. These figures represent only the value of mineral materials as they are mined or otherwise extracted from the Earth. They do not reflect the value added to these materials through downstream processing within the facilities commonly accepted as mineral industry plants. That is, value added through beneficiation of ores, smelting, refining, and similar processing is not included in these figures. Comprehensive world data on the value added by such processing are not available; however, a conservative estimate of the total value of processed output from mineral industry plants derived wholly from primary (newly mined) materials would be on the order of about $2,800 billion constant 1983 dollars or $3,900 billion in terms of 1992 dollars.

Jan 1, 1994

By John J. Henn

Two lime sinter processes for recovering alumina from clay, the double-leach process and the single-leach process, are evaluated in this Bureau of Mines report. In both processes, clay and limestone are mixed and sintered to form calcium aluminate from which alumina is extracted as sodium aluminate by leaching with a dilute solution of sodium carbonate. The pregnant liquor is desilicated, then carbonated to precipitate alumina trihydrate which is recovered and calcined to a,-alumina. The fixed capital costs for plants producing 1,000 tons per day of alumina are $85 million for the double-leach process and $86 million for the single-leach process based on a Marshall and Stevens chemical equipment index of 240.0. Because plant locations are variable with respect to the proximity of clay and limestone deposits, a nomograph is included to determine operating costs at various delivered costs of clay and limestone. For plants at which the delivered cost of clay containing 30 percent A1203 is $2 per ton and the delivered cost of limestone is $1 per ton, the operating costs are $81.04 and $89.87 per ton of alumina for the double-leach process and single-leach pro-cess, respectively.

Jan 1, 1969

The results of a Feasibility and Design Study of Surface Impregnation Equipment to be used for Chemical Stabilization of Coal Mine Structures are described in this report. The study was sponsored by the United States Department of the Interior, Bureau of Mines, under Contract H0210055. This program was undertaken as an essential part of the Bureau of Mines Chemical Ground Stabilization Program. The responsible prime contractor was The Eimco Tunneling and Mining Machinery Division of the Envirotech Corporation. The Rocketdyne Division of the North American Rockwell Corporation performed part of the feasibility study and design and testing of the metering and feed system as a subcontractor to Eimco.

Jan 1, 1972

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Jan 1, 2011

By A. L. Engel

The sample of ore on which the work described in this paper was done came from Mina Oriente, Carrizal Bajo, Provincia de Atacama, Chile, South America, and was sent at the request of the Chil.ean Government through the Foreign Minerals Division of the Bureau of Mines. This ore had been tested locally for treatment by flotation and cyanidation without satisfactory results. An additional difficulty was the absence of water near the ore deposits, so that in any treatment method considered the water requirements would have to be very low. It was desired to develop a practical method of recovering the gold and, if possible, the copper in the area. No data of previous investigations were made available. The sample received was mostly quartz, highly brecciated, with limonite and hematite in the fractures. Copper occurred as malachite and azurite, also in the fracture s and to a slight extent as a stain in the quartz. Some fine-grained pyrite with a little arsenopyrite occurred within the quartz. An occasional grain of chalcopyrite was observed. No free gold was seen during examinations of the ore, but amalgamation indicated that some was present.

Jan 1, 1949

By J. J. Demeter

Anthracite from the four producing regions in Pennsylvania was both ashed in the laboratory and burned on a chain-grate stoker to determine the sulfur-retention properties of its ash. The retention of sulfur in laboratory-prepared anthracite ash was shown to be related to ashing temperature and to the amounts of sulfur and calcium present in the coal. At the usual laboratory ashing temperature of 750° C sulfur retention ranged from 0.8 to 13.2 percent of the total coal sulfur. Sulfur retention in the ash was negligible, o to 0.3 percent, at 1,200° C, which is the thermal decomposition temperature of calcium sulfate; thus calcium sulfate does not form and cannot serve as a sulfur-retaining agent. In several tests the anthracite was mixed with 6 or 10 percent dolomite prior to firing in the chain-grate stoker. The dolomite did not improve sulfur retention owing to the high temperature in the fuel bed. Sulfur retention was, however, related to the unburned carbon in the ash. The relationship of the percentage of original coal sulfur retained in the ash (Y) to the percentage of the original carbon in the coal remaining in the ash (X) is expressed by Y = -0.579 + 0.914X. The percentage of sulfur retained is almost directly proportionate to the percentage of original coal carbon in the ash.

Jan 1, 1968

By Alan R. Buehler

A mineral survey of the 20,792-acre Sand Butte WSA (Wilderness study Area), ID-57-8, was conducted by U.S. Bureau of Mines personnel in 1985, at the request of the Bureau of Land Management. The WSA is in Lincoln County, south-central Idaho, about 15 miles south-southeast of Carey. There are no mines, prospects, or claims within the WSA. Basaltic lava is the only rock type exposed within the WSA. The only mineral resource is a few tons of a platy variety of lava (slab pahoehoe) which is suitable for use as decorative stone. Similar slab pahoehoe, produced from other lava fields in southern Idaho, retails for approximately $125/ton. The deposit in the WSA is too small to be mined commercially but may have value to consumers who gather their own decorative stone. INTRODUCTION A mineral survey of the Sand Butte WSA (Wilderness Study Area) 1/ was conducted in June 1985 by the USBM (U.S. Bureau of Mines) and the USGS (U.S. Geological Survey) at the request of the BLM (U.S. Bureau of Land Management). The USBM examines individual mines, prospects, claims, and mineralized zones, and evaluates identified mineral and energy resources. The USGS evaluates potential for undiscovered resources based on areal geological, geochemical, and geophysical surveys. Results of the investigations will he used to help determine the suitability of the WSA for inclusion into the National Wilderness Preservation System. The immediate goal of this and other USBM mineral surveys is to provide data to the President, Congress, government agencies, and the public for land-use decisions. The long-term objective is to ensure the Nation has an adequate and dependable supply of minerals at a reasonable cost.

Jan 1, 1986

By H. E. Sanford

"INTRODUCTION Of the occupations in and about coal mines, those of the haulage crews are among the most hazardous. Statistics indicate that the second largest number of fatalities about coal mines occurs during haulage operations and through the use or misuse of haulage equipment. Despite the fact that relatively few coal-mine employees are engaged continuously at haulage operations, approximately 20 percent of all coal-mine fatalities are attributable to haulage.Most of the hazards in haulage operations could be very greatly reduced if more serious consideration were given to the problems of the haulage crews and if sincere efforts were made to reduce the hazards. Underground haulage is similar in many respects to railroading; yet, railroading is now considered one of the safest of occupations a distinction that has been attained only by honest effort and whole-hearted cooperation on the part of all concerned. Underground haulage is also similar to street and highway operation and has in it some of the difficulties encountered in the reduction of traffic accidents the seriousness of which has not by any means been con¬trolled as yet, notwithstanding the fact that much effort has been expended through a multiplicity of laws, ordinance regulation, etc., as well as by thousands of enforcement agencies and officers.The men working on the locomotives are among the most important members of a coal-mine organization; without skilled haulage employees, the production of coal would be greatly retarded. Their jobs, particularly the job as brakeman, require physical endurance, agility, and mental and physical alertness; in thin coal beds, especially where the roof is not brushed and the coal is loaded into mine cars by hand, the need for these qualifications is greatly increased."

May 1, 1948

By Franxis Church Lincoln

"INTRODUCTION During September 1944, the Bureau of Mines undertook a program of investigation and limited exploratory drilling at the Last Chance mine, near the village of Arthur in Grant County, Wisconsin, as part of a general investigation of the zinc-producing area of southwestern Wisconsin when every effort was being made to increase the production of metals important to the Nation's war program.The Bureau's attention was directed, to the Last Chance mine when the operators discovered high percentages of zinc in an exploratory churn drill hole a short distance southeast of the mine. The ore was found in the Trenton Limestone, which underlies the ore horizon then being mined. To determine whether this discovery was important, and to demonstrate the possible extension of the ore the Bureau of Mines drilled five additional holes in the vicinity of the discovery.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Nines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report."

Mar 1, 1947

By W. W. Weller

Low-temperature heat capacity measurements were conducted, and entropies at 298.15° K were evaluated for sodium monomolybdate (Na2Mo04), magnesium monomolybdate (MgMo04), and calcium monomolybdate (CaMo04). The 298.15° K entropy values were sodium monomolybdate, 38.1±0.3 cal/deg mole, magnesium monomolybdate, 28.4±0.2 cal/deg mole, and calcium monomolybdate, 29.3±0.2 cal/deg mole.

Jan 1, 1963

By W. E. Miller, Kennedy. R. E., G. W. Jones

"INTRODUCTION Ethyl mercaptan (CH3,CH2SH), a combustible organic liquid of the thioalcohol type, is employed at an odorant in many types of fuel gases and dangerous atmospheres, which in themselves are devoid of characteristic odors, to give warring against leakage of such gases or atmospheres into places where they might constitute health or explosion hazards.Ethyl mercaptan has a penetrating disagreeable odor resembling that of onions, garlic, hydrogen sulfide, or rotting cabbage, that exceedingly low concentrations of it can be detected. The of odorants as a beans of detecting leakage of gases and atmospheres has been investigated extensively by chemists and engineers of the Bureau of Mines, and numerous reports as to its value have been published."

Jun 1, 1942

By D. D. Bolstad

This report describes the construction and use of a direct-reading azimuth protractor (DRAP) by the Bureau of Mines for measuring fracture orientations in mines, tunnels, or other excavations having a magnetic environment. The DRAP allows a rapid and simultaneous measurement of dip and azimuth of dip of a fracture plane. The instrument is rugged, lightweight, and easily constructible from standard hardware items. The DRAP can measure dip to within ±0.5° and azimuth of dip to within ±5° of corresponding values obtained with a Brunton compass.

Jan 1, 1974

By David R. Hanson

Experimental work performed by the Bureau of Mines in a laboratory environment has shown that the formation of failure zones within certain rock types is accompanied by the emission of significant amounts of radiofrequency (RF) electromagnetic (EM) energy. This radiation was detected using nonresonant, "electrically short," broad-band antennas. Rock types for which emission was observed include granite, quartzite, and taconite; sandstone and marble did not emit measurable radiation. Amplitude spectra of the radiation showed the energy to be concentrated between 10 and 40 kilohertz. These data indicate that emission is directional, but this has not yet been proven. In addition, amplitude of RF emission increases with increasing crack size. Since emission was observed only for brittle quartz-bearing rocks, it appears the formation of piezoelectric fields is a necessary condition for RF radiation. Plausible mechanisms for emission include rapid decay of piezoelectric fields accompanying the sudden stress release at failure and/or the acceleration of an "exoelectron plasma" through the intense local piezoelectric fields. Since emission appears to increase with the scale of failure, and since antennas do not need to be coupled directly to rock surfaces as with conventional geophones, the possibility of developing a portable system to monitor seismically active areas exists.

Jan 1, 1981

By G. B. Shea

The accident experience of the California petroleum industry for 1927 was characterized by a decrease it .the number of fatalities. The year closed with a total of 41 fatal accidents, as compared with a total of 54 for the preceding year. 3 In percentage, the figure for 1927 represents a decrease of 24 per cent from that of 1926 and evidences the promising results of organized safety work, in which the industry in California has taken an absorbing interest. The percentage of decrease for 1927 is the largest recorded in any one year since the compilation of the fatality record in the California petroleum industry was begun. Although good progress has been made during the past few years, much remains to be done to reduce still further the human and economic waste caused by accidents. This review is intended to show the employee, as well as the employer, the proximate and contributing cause of accidents. To increase the value of the report, preventive measures in various instances are suggested, on the theory that accidents of a similar nature will occur unless remedial action in taken to remove the cause.

Jan 1, 1928