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By J. P. May

This U.S. Bureau of Mines report identifies and evaluates factors responsible for dump-point accidents involving mobile mining equipment. Information regarding the occurrence and severity of the accidents, the industries affected, the types of equipment involved, the primary and contributing causes, and pertinent Federal regulations is included. The aim of this report is to provide information that will aid mine operators in the recognition of hazards associated with mobile equipment operation near the dump points of stockpiles and waste dumps.

Jan 1, 1990

By A. H. Shoemaker

This paper describing the mining practices at the Old Dominion mine, Globe, Ariz., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various minim districts in the United States. The Old Dominion mine is situated in the eastern port of the Globe-Miami district, about 1-1/2 miles north from the center of the town of Globe. An average of nearly: 1,200 tons per day was mined during 1928. The prevent production is about 1,500 tons per day; of this amount,, approximately 100 tons is direct-smelting ore that is shipped to the smelter at Miami and 1,400 tons milling ore which is treated in the company?s concentrator at Globe. About 600 men are employed at the mine.

Jan 1, 1930

By Engelmann. William H.

In pursuit of innovative methods to improve mining productivity, the Bureau of Mines is investigating the use of inorganic salts as drilling fluid additives for penetration enhancement. Laboratory diamond drilling tests were performed on Westerly Granite with aluminum chloride solutions and on Sioux Quartzite with aluminum nitrate and aluminum, calcium, sodium, and zirconium chloride solutions as drilling fluid additives. These drilling results were compared with the average drilling performance using distilled, deionized water on Sioux Quartzite (12 replicate tests) and Westerly Granite (3 replicate tests). Maximum in-creases in penetration per given time and bit life were obtained when drilling with zero point of charge (ZPC) concentration solutions of each additive. For Sioux Quartzite, maximum increases in penetration and bit life ranged from 96 to 115 pct and 64 to 99 pct, respectively. For Westerly Granite, maximum increases in penetration of 155 and 165 pct and bit life of 109 and 136 pct were obtained at or near ZPC aluminum chloride concentrations of quartz (7.3 x 10-7 mol/L AIC13) and alkali feldspars (1.1 to 1.5 x 10-6 mol/L AIC13), respectively. This simultaneous increase in penetration per time together with extended bit life should result in increased productivity and reduced bit costs.

Jan 1, 1987

By Foster Fraas

Under a very high vacuum of 10-8 torr the transfer of terrestrial mineral beneficiation methods to the vacuum ambient of extraterrestrial locations such as the lunar surface was investigated. In the size range for the electro-static and magnetic separation of ores (minus 35 plus 150 mesh) there is no adhesion of particles produced by crushing and grinding due to the limited contact area, and for repeated contacts area size has a frequency of occurrence in accordance to the normal law. The photoelectric effect which is successful in separating a few minerals in an air ambient has a wider application in a vacuum, while the lack of air viscosity and sound transmission provides for high feed velocities and the adaptation of particle vibration to dispersion and grinding. Contact electrification is reversible upon return to atmosphere.

Jan 1, 1970

By Richard J. Bielicki

The possibility of replacing the brattice cloth closest to the coal mine working face with an air curtain mounted on top of a continuous-mining machine or with a diffuser fan was explored by the Bureau of Mines. Preliminary tests conducted at a full-scale model working face with the brattice end set at 18 feet showed that the air curtain improved face ventilation only slightly and was not nearly as effective as placing the brattice at 10 feet. A 2,000-ft3/min diffuser was more effective than the air curtain. It is concluded that the air curtain probably could not function as a line brattice extension, although the diffuser fan may have some potential.

Jan 1, 1975

By Michael Rieber

The increase in f.o.b. mine prices of coal from $5/ton to over $18/ton in five years [1] has increased the significance of transportation costs. Coals produced in the vicinity of the consumer bear a much lower transport cost than those produced in the west. This differential may be used for flue gas desulfurization, other cleaning, or further processing of local coals. To the extent that western coals are cheaper to produce and have a lower sulfur content, they offset the locational disadvantage. To the extent that they have a lower heating value, the disadvantage is exercabated. Given the other conditions, an accurate analysis of transport costs will help suggest the location of coal mining and the moue of transport both transport costs and tariffs have risen. Together they have increased delivered coal prices, altered the balance between the use of coal and other fuels, helped to alter the location of mining activity, and put pressure on consumers to examine the cost effectiveness of alternative transport modes. Transportation options for long distance coal movements include rail, barge, pipeline, and EHV transmission lines. A summary of system parameters is shown in Table 2.1. Barge transport, pneumatic and slurry pipelines are discussed elsewhere in this report. Together with EHV, they have been the subject of previous studies [2,3,4]. Slurry pipelines have been shown to be especially useful where rails are not available [2] but the technical problems of dewatering, handling, and utilization of lines [5] remain unresolved. They are discussed in Section 3. Barge transportation depends on the location of the mine and consumer with respect to the waterway system. One drawback of barge shipment is interruptions due to winter, and low or high water conditions. Mine mouth power generation followed by EHV transmission of over 500 miles has been shown to be the most expensive means of delivering an equivalent amount of energy to consumers [2].

Jan 1, 1977

By L. W. Higley

Procedures were developed for reclaiming high-temperature alloy scrap in the form of standard cobalt-base alloy. A cobalt-base, multicomponent, high- temperature alloy, such as S-816, can be successfully melted from scrap, and its specified chemical composition can be retained. Induction furnace melting in a controlled atmosphere was used to obtain ingots that were subsequently fabricated by impact forging to provide specimens for heat treatment and testing. Of the numerous metal elements in S-816 alloy, only small quantities of molybdenum were lost in the melting operation as finally developed. Test results indicated that the scrap material, after melting, forging, and heat treatment, was equivalent in room-temperature tensile strength, in high-temperature creep and stress-rupture properties, and in chemical composition to commercially produced S-816 alloy made from virgin material.

Jan 1, 1963

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By Oliver Bowles

This report covers the character, properties, origin, occurrence, and uses of the traprocks and describes briefly the methods and equipment employed in quarrying and preparing them for market. Production of traprock occupies an important place in industry. In 1960 the output in the form of crushed stone reached nearly 58 million tons valued at $87 million. Traprocks are also shaped into blocks of dimension stone for monuments, building construction and decoration, and specialized products such as surface plates.

Jan 1, 1963

By F. J. Perzak

The Bureau of Mines conducted a study to develop a standard fire test for 5-gal containers used for storing combustible fluids in underground coal mines. A standard test method was developed which evaluates the performance of the container in a 4-min tray fire. Bureau investigators used the standard test method to evaluate several types of closed 5-gal plastic and metal cans in outdoor tests. Each can tested contained 1 gal of nonfire-resistant (NFR) hydraulic oil. A container failed the test if it lost its contents in any of seven trials. Contents spilled either as a result of thermal rupture or melting. Fewer than 10 pct of the metal containers failed this criterion, but all the plastic containers failed. The metal container failures were usual-ly due to tipping over during pressure relief, which spilled the NFR oil. Replacing the NFR oil in the container with kerosene resulted in failure of more than 30 pct of the metal containers. The standard tests and preliminary tests showed that plastic containers are not equivalent to metal containers in their ability to contain combustibles such as lubricants and greases in a fire. For solvents and lubricants more volatile than NFR hydraulic oil, approved metal safety containers are recommended.

Jan 1, 1985

By E. H. Illsley

This bibliography is the first report of a Bureau of Mines research project on thermoelectric materials. Interest in such research has increased because of recent success in the design of commercial products, including generators and refrigerators, using the principles of thermoelectricity. This success made possible by the discovery of semiconductors that have much higher [effincies] than the metals and alloys formerly studied. Thermoelectricity is a term that includes a large number of phenomena relating heat to electrical energy. However, the moat important applications arise from two effects discovered by Seebeck in 1822 and by Peltier in 1834. When pieces of two unlike materials are joined at their two ends to form a continuous circuit, both of these effects may be observed. If the two junctions are maintained at different temperatures, an electromotive force known as the Seebeck voltage is generated. If, on the other hand, a current is made to flow through the circuit, the junctions of the materials will be found to differ in temperature. This phenomenon is called the Peltier effect.

Jan 1, 1959

By W. P. Huleatt, Jr. Traver, Jr. Hazen

"Vanadium and uranium occur widely distributed throughout western Colorado and eastern Utah, and a few deposits have been found in northeastern Arizona and northwestern. New Mexico. The area in which it occurs includes approximately 10,000 square miles and is generally referred to as the vanadium region of Colorado and Utah.The majority of the deposits consist of replacement bodies and impregnations of rare minerals in the lower Morrison formation of Jurassic age. The ore bodies are flat, with irregular margins, and most of them conform to the stratification.The ""rim rock"" topography of the region includes many steep-walled canyons and plateaus, which afford an abundance of outcrops that have been responsible for most of the discoveries of mineralized areas. Delimitation of ore bodies within the areas is accomplished most effectively by core drilling from the surface.The deposits were discovered in 1899 and from 1911 to 1923 wore worked extensively for radioactive uranium ores, principally carnotite.The discovery and marketing of the richer and more cheaply mined pitch-blende ores of the Belgian Congo left the Colorado-Utah deposits without economic importance as sources of radium and uranium, and the region became inactive in 1923. After a period of comparative inactivity, the rising demand of the alloy-steel industry for vanadium renewed interest in the deposits, which were known to contain that metal. By 1938, vanadium production in the area had achieved respectable proportions, and new impetus was given to it by the United States’ entry into World War II in December 1941. In 1942, new treatment plants for vanadium ores were completed in Monticello, Utah, and Durango, Colo. In order to meet the requirements of these and other plants in the region, it became necessary to open new vanadium mines and prepare old onus for production.In an effort to stimulate mining, the Metals Reserve Company initiated a stock-piling program and appointed the united states Vanadium Corporation, to act as its purchasing agent.The extra production was expected to come largely from small, independent operators whose limited funds did not permit them to maintain development and exploratory programs. Study of conditions made it apparent that extensive exploration would be necessary to sustain production, and accordingly the Bureau of Mines initiated an exploratory drilling project on a cooperative basis with the Geological Survey. The principal objects of the work were to enlarge the known ore reserves of the area and, if possible, discover new ones. The results have been gratifying in both respects."

Sep 1, 1946

By R. E. Head

[Recent investigations at the Intermountain Experiment Station of the Bureau of Mines at Salt Lake City indicate that metallurgists have given little attention to the occurrence of jarosite minerals in the oxidized ores of lead and silver. These investigations have also emphasized the importance of lowing when these minerals occur in the oxidized ores, especially those containing lead, silver, and gold, as their presence is a material factor in selecting a suitable kind of treatment. Since the question of the occurrence of jarosites in oxidized ores has come to the attention of the Bureau of Mines, investigation has indicated that plumbojarosite and argentojarosite are quite common. These two minerals appear to be widely distributed and probably escaped recognition by persons who had attempted to treat certain oxidized lead ores in which the jarosite minerals represented a material portion of the metal content. Consideration of the physical characteristics of the jarosites also indicates that in many cases failure to treat some of the oxidized lead ores with success has been directly due to the fact that the greater portion of their lead and silver content was present as plumbojarosite and argentojarosite. The data and the description of these minerals given in the body of this paper indicate that attempts to recover lead and silver from ores in which appreciable amounts of too metals occur is plumbojarosite and. argentojarosite would be unsuccessful if confined to gravity methods of concentration. There are undoubtedly considerable tonnage of oxidize lead ores in the various mining regions of this and other countries, and it is quite probable tat in some of these ores the metal content of lead and silver may be largely anglesite (lead sulphate) and cerussite (lead carbonate) but that they will also contain cerargyrite (silver chloride), argentojarosite, and plumbojarosite. The treatment of such ores therefore presents an important problem, since a product is discarded from]

Jan 1, 1928

By Charles D. Litton

This U.S. Bureau of Mines report describes the results of two large-scale tests conducted to evaluate a prototype nitric oxide (NO)-compensated carbon monoxide (CO) fire sensor, developed by Carnegie Mellon Research Institute (CMRI). In the tests, small coal fires were allowed to develop in the presence of diesel exhaust at relatively low ventilation airflows. These tests compared the response of the CMRI fire sensor with that of other fire sensors, including the Bureau's diesel-discriminating smoke detector. During the tests, CO, NO, and smoke levels were continuously monitored in order to determine the sensor alarm times and gas levels as the fire developed. The data indicated that the NO-compensated CO fire sensor was capable of suppressing the CO produced by a diesel engine and that the sensor responded reliably to the CO produced from the test fires. The tests also showed that the Bureau's diesel-discriminating smoke detector alarmed earlier than the prototype NO-compensated CO fire sensor.

Jan 1, 1993

By John A. Kiefer

Ground fault and overcurrent protection criteria for coal mine a.c. distribution systems were examined under a Bureau of Mines funded investigation. The report begins with a literature review which discusses relaying topics including instrument transformers, ground-fault pickup methods, static relaying, and comparison of relaying techniques. A chapter on ground-fault relaying provides recommendations for maximum and minimum pickup levels as a function of maximum ground current and power system line-to-ground capacitance. Research in the area of phase overcurrent protection has resulted in a complete set of procedural recommendations for the selection and setting of overcurrent relays and current transformers, molded-case circuit breakers, and distribution system fuses in coal mine power systems. The final chapter, which discusses relay system maintenance, introduces a unique test set which was developed by KETRON and used to test the performance of relaying systems in coal mines.

Jan 1, 1980

By W. J. Kroll

This investigation was undertaken with the idea of studying a number of unconventional methods for making chromium to determine whether production cost could be lowered and to discuss some of the more recently described processes. These comprise carbon reduction of the oxide in vacuum, nitride dissociation, fusion electrolysis of the chloride, amalgam method, iodide dissociation, calcium reduction of the oxide, hydrogen reduction of the chloride, and reduction of this compound with zinc and with magnesium. Preference is given this latter method, which is shown in a flow sheet. Special attention is given purification of the chloride and separation of the vacuum at about 900° C. A reduction method for the elimination of traces of oxide contained in pure chromium by pure hydrogen obtained from the dissociation of zirconium hydride is described. The various methods are compared in a table in the appendix. Aluminothermic and silicothermic methods for the reduction of chromium oxide and the aqueous electrolysis have been disregarded in this investigation.

Jan 1, 1950

By L. G. Marshall

This report, describing the mining method of the Dresser Trap Rock Co., Dresser, Wis., is one of a series published by the Bureau of Mines on mining methods, performance, and costs at mining operations throughout the United States. SUMMARY Dresser, in Polk County, is 3 miles south of St. Croix Falls, Wis. Company operations are about 1 mile north of the townsite. The mine has been in [peration] since 1914 and under the present ownership since 1949.

Jan 1, 1959

By Charles Seitz

The Bureau of Mines has modified its parts-per-billion helium-4 analyzer to improve the analytical capabilities of the instrument. The modifications resulted in the following improvements: (1) The analytical precision of the instrument for 10 consecutive analyses was improved to ±1 ppb at the 5,000-ppb helium-4 level, (2) the helium-4 sensitivity was increased almost tenfold, and (3) the minimum detectable limit for helium-4 was improved to 0.5 ppb. The modifications made to improve the instrument included replacing the ion-source control circuit with a direct-current solid-state design, controlling the temperature of the ion source, stabilizing and reducing the pumping rate of the vacuum system, and optimizing peak integration.

Jan 1, 1986

By Joseph A. Vanous

The inductive communication system was developed under this contract for use in the hoist of deep mines. This program was a four phase program with experimental dual frequency equipment resulting from Phase I, emergency single frequency equipment developed under Phase II, and equipment documentation required under Phase III. An additional emergency system was provided under Phase IV.

Jan 1, 1976

By Maria I. De Rosa

High temperatures encountered by mine rescue teams during emergency situations may cause severe physiological strain, hindering the men from carrying out rescue and recovery missions. A prototype ice-cooling garment (ICG) was developed by the Bureau of Mines to alleviate physiological strain due to heat stress. The effectiveness of the garment was tested with acclimatized and unacclimatized subjects at a typical work rate (1,200 Btu/hr) expected during rescue operations and at various hot environments (97° to 113° F dry bulb and 80° to 89° F wet bulb). During exposures with the ice cooling garment, the subjects were able to maintain a safe deep body temperature of 100.4° F or below Without the garment, the deep body temperature rose beyond values of 100.4° F, a condition considered unsafe for continuous work in hot conditions. Both heart rate and skin temperature values were lower while wearing the ICG. Subjective observation also indicated a marked benefit by wearing the ICG.

Jan 1, 1976