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By G. S. Scott

The flammability of trichloroethylene vapors in air has been determined in a 7-inch cyclindrical vessel. Saturated flammable mixtures were formed with air at atmospheric pressure between 30° C (86° F) and 82° C (180° F); the trichloroethylene concentrations at these temperatures are 12.5 (lower) and 90 (upper) volume-percent, respectively. Further study is necessary to assess the effects of different variables on the flammability of this material. INTRODUCTION Trichloroethylene (TCE) (ClHC = CCl2), sold under various trade names (Blacosolv, Perm-A-Clor, Tri, Triad, Triclene, Trivec, Tromex, Vapoclean, Vapoclor, Westrosol, etc.), is an important industrial chemical. A summary of its physical and chemical properties is given in table 1. It is used to degrease metals, leather, and textiles, to extract residual oils from vegetable oil cakes, for dry cleaning, and in soap. It is a powerful solvent for fats, resins, bitumens, rubber, sulfur, and phosphorus. Several explosions in which trichloroethylene was involved prompted an investigation by the Bureau of Mines to determine the conditions under which such accidents can occur.

Jan 1, 1963

By Robert F. Kehrman

As with many new technologies, the rapid growth in solution mining for uranium has created uncertainties regarding the environmental impact of mining operations. In solution mining, the largest area of concern is the impact of the process on the quality of ground water supplies. As a result, a rapid and reliable technique of detecting lixiviant excursions is desirable. Such a method would replace the periodic sampling technique and should provide a more or less continuous monitoring method. To this end, resistivity techniques were evaluated as an alternate means of tracking lixiviant movement. A program was devised which had five specific tasks. These were: (1) evaluation of the techniques, (2) development of the most promising technique or techniques, (3) field testing of the techniques, (4) testing of the BuMines probe, and (5) reporting. The result of the analytical and field work is that various resistivity/ resistance techniques do provide a means of detecting lixiviant movement in Northern Wyoming. Surface and downhole galvanic surveys and controlled source audio magnetotellurics (AMT) were evaluated. All three techniques showed some degree of success.

Jan 1, 1979

By L. Cheng

This Bureau of Mines report summarizes an investigation of the amount of respirable dust adhering to the surfaces of seven run-of-face broken bituminous coals. The number of respirable-size (0.9 to 10 micrometers) particles adhering to the run-of-face coal ranged from 1011 to 1012 particles per pound of coal and was approximately inversely proportional to the mean lump size of the coal sample, otherwise it did not vary significantly with the coal seam, mining method, or winning machine. Based on these results, about 16 lb of ordinary run-of-face broken coal would have enough respirable-size adhering dust to contaminate 1,000,000 ft3 of air up to the 2 mg/m3 level, if this adhering dust should become airborne. Although brief studies here suggest that a negligible amount of new respirable dust is formed due to fracture of the broken coal during dropping, dislodging of old adhering particles during secondary handling operations is a potentially dangerous source of airborne respirable dust.

Jan 1, 1973

By Sidney Katell

Continuing the series of cost bibliographies which was initiated with the publication of Information Circular 7516 in October 1949, the present report covers the period from January 1959 through December 1959. The abstracted articles, concerned with all facets of cost engineering in the field of petroleum and chemical plants and related facilities, were obtained from the following sources: 1. Bureau of Mines Information Circulars. 2. Bureau of Mines Report of Investigations. 3. Chemical Engineering. 4. Chemical Engineering Progress. 5. Chemical Week. 6. Coal Age. 7. Coal Utilization. 8. Cost Engineering. 9. Industrial and Engineering Chemistry. 10. Nucleonics. 11. Oil and Gas Journal. 12. Petroleum Engineering. 13. Petroleum Refiner. 14. World Oil. On Oct. 16, 1959 a cooperative agreement between the Bureau of Mines and the American Association of Cost Engineers became effective. This agreement provides for the publication of the annual bibliography under the sponsorship of both groups with the work load involved in the preparation divided equally between the two. As a result, the present report partially reflects the efforts of the members of the Association.

Jan 1, 1960

By L. C. IlsLey

Figure 1 is a reproduction of a chart recently prepared by the Bureau of Mines at its Pittsburgh Laboratory to show the Bureau's approval work in connection with electrically operated mining equipment. Nearly 27 years of approval work, covering 346 approved units, are shown on this chart. These approvals are arranged according to year of approval and the manufacturer to whom approval was granted. Forty-five manufacturers are represented, and a scheme of using various colored tabs permits the following subdivision of the equipment: Cutting machines, loading machines, conveyors, battery-operated locomotives, battery-operated power trucks, drills and drilling machines, rock-lusting machines, pumps, room hoists, air compressors,, and miscellaneous, The greatest number of approvals granted to a single manufacturer is 80; the next highest is 65, and the third is 49. Several manufacturers have been granted only a single approval. The chart shows all approvals granted for, motored equipment. Some of these units have since become obsolete, and a few are used to a very limited, extent if at all.

Jan 1, 1941

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

6. Development of Mine Sealant Material Systems 6. 1 Introduction The preliminary evaluation of material systems described in Section 3 led to the selection of the following four promising systems for further development: System A: Aggregate, Fly Ash System System B: Aggregate, Fly Ash, Urethane Foam System System C: Aggregate, Bulkhead, Light Expansive Concrete System D: Aggregate, Self-Supporting Thick Slurry Preliminary laboratory tests indicated that the building of effective bulkheads from one borehole would be extremely difficult. Two extra boreholes would be required adding to the overall cost of the system and making the system less attractive. Tests with light expansive concrete showed that bulkheads would be required, the material would not support itself. As a result, further development of this system was terminated. Foam concrete was selected as the most suitable material to be developed into a self-supporting, rapid-setting slurry. A laboratory investigation of its use for mine sealing was conducted during this program; the results are summarized in Section 6. 5 and details of the laboratory program are presented in Appendix B.

Jan 1, 1973

By H. Robert Ensminger

As a result of the new mining law implemented in August 1985 and the programs conducted by the Institute Ecustoriano de Mineria (INEMIN), which was created by this legislation, there was considerably greater activity in the nonfuels mineral sector during 1986. Over the next 2 years, INEMIN will be developing a national mining plan that will guide Ecuadorean mineral development for the balance of this century. As stage one of INEMIN's mineral study, historical records were reviewed and 300 abandoned mines and 1,200 unexplored mineral deposits were available for further investigation. In 1986, INEMIN established 5 branch offices and negotiated 250 new mining contracts with foreign companies valued at $16 million. Despite all this activity, INEMIN officials estimate that 100,000 square kilometers remain available for claim staking. Technical assistance contracts were signed with Belgium, the Federal Republic of Germany, Italy, Spain, and the United Kingdom, to assist in a variety of assignments ranging from helping prepare the national minion plan to the development of industrial mineral deposits.

Jan 1, 1988

By Norwood B. Melcher

This report describes preliminary experiments by the Federal Bureau of Mines on the practicability of adding raw pellets of taconite concentrate to blast furnace feeds. The usual industrial practice is to harden the pellets by heating before they are charged to the furnace. The Bureau research demonstrated that raw pellets could be successfully smelted in an experimental furnace with no significant change in coke consumption and only a moderate increase in dust losses. The dust loss was 43 pounds per ton of metal for an all-pellet charge, compared with 7 pounds per ton for an all-sinter charge. Raw taconite pellets undergo only slight degradation during charging to the furnace if 1 percent bentonite is used as a binder. INTRODUCTION Fines and concentrates must be consolidated or agglomerated into larger masses before they can be smelted in a commercial blast furnace. Such agglomeration is usually done by sintering, pelletizing, nodulizing, or briquetting. Sintering has been the more common practice, but with the advent of taconite concentrates pelletizing is increasing in importance.

Jan 1, 1960

By A. V. Petty

In accordance with its objective to maximize minerals recovery from secondary domestic resources, Bureau of Mines conducted research on recycling chrome refractory wastes. Since 20 pct of the U.S. demand for imported chromite is used in the production of refractories, primarily for the steel, copper, and glass industries, samples of used chrome-containing refractories from copper converter and reverberatory furnaces were investigated to determine their potential for recycling. The samples were beneficiated using a combination of wet magnetic separation, flotation, and leaching techniques, and the concentrates were reformed into briquets for refractory evaluation. Small refractory test specimens produced from the beneficiated concentrates gave modulus of rupture values at 1,350° C comparable to those of commercial mag-chrome brick of similar composition; however, grinding the waste refractories to at least minus 65-mesh was required in order to liberate the metallic copper. Most of the copper was easily recovered using conventional beneficiation techniques, but the finely ground chrome concentrate would require briquetting, calcining, and crushing to produce a coarse grain suitable for recycling into secondary mag-chrome refractories.

Jan 1, 1981

By P. G. Barnard

Losses of alloying metals in furnace flue dusts, grinding swarfs, and mill scale produced during the manufacture of stainless steel are substantial. About 25 million lb Cr, 8.7 million lb Ni, and 150,000 lb Mo and other critical metals can be made available annually for recycling by a process developed by the Bureau of Mines. Stainless steel wastes pelletized with a portland cement binder were reduced in a small electric-arc furnace by a two-stage process to produce a recyclable alloy containing Cr, Ni, Mn, and Fe. The initial reduction was with carbon; the second, with ferrosilicon. Results are compared with previously reported laboratory induction melting tests. A 2,000-lb demonstration test of the process in a commercial electric-arc furnace is also described. Data are also presented on three 1,500-lb tests made using various slag conditions in the electric-arc furnace. Recoveries up to 99 pct of the Fe, Cr, and Ni contents of stainless steel wastes were obtained in using the process.

Jan 1, 1977

By Ronald D. Hill, Elmore C. Grim

Mining as an extractive process alone is outdated and unacceptable to today's environmentally concerned public. Multiple land use must be considered as well. Only through effective preplanning can the full potential of reclamation result in a lasting asset for future generations. The coal industry is now recognizing that reclamation of mined lands is part of the mining cycle that must be planned and carried out in a timely and orderly manner. It is also finding that planning reclamation in advance of mining is cheaper and more effective than waiting until mining is completed. The decision to open a strip mine must be based on the results of studies to determine if successful reclamation can be achieved and whether the economic benefits to the company will be justified(1). Information regarding the physical, chemical, hydrologic and biologic systems operative at the site must be under- stood or reclamation will be a failure. Working together, engineers, management and reclamation specialists should design the actual mining and reclamation plan before mining is begun.

Jan 1, 1974

By Paul M. Linebarger

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 rights of American citizens to explore for minerals and to own and operate mines in various foreign countries. This interpretation of the laws of Mexico has been pro oared from the best information available in Washington but is released subject to correction and amplification, if necessary, by the proper American diplomatic and consular officers, to whom it has been referred through the courtesy of the Department of State. INTRODUCTION Present-day Mexican mining legislation involves, not only the latest minim enactment (August 1, 1026), but many other enactments and regulations, principal among which are the Constitution, the Civil Code, the Code of Commerce, the Foreign Law, the Mining Tax Law, and. the Civil Jurisprudence of Mexico--the last-mentioned being based in Dart on Supreme Court decisions. Ere Mexican Federal Government is supreme in mining legislation because, among other reasons, a large part of the revenue of the Government must come from the fiscal control of the mines. All circulars, decrees, and rulings that affect the mines not only have their origin in the Central Government but are administered thereby. The Department of Industry, Commerce, and Labor is in control of all mines. Attention may here be called, however,

Jan 1, 1929

By Joseph E. Chilton, Robert J. Timko, Charles D. Taylor

No regular monitoring of methane is required in areas of gassy coal mines outby the mining face. Methane ignitions that have occurred in mine outby areas indicate the need to provide better protection to workers. Handheld methane monitors are now used by some miners to make periodic measurements of methane at the working face. The IYONI II gas detector which is incorporated into a miner’s cap lamp and worn on a miner’s helmet can continuously provide an alarm signal whenever methane levels exceed a set level. Tests were conducted to evaluate the performance characteristics of this methane detector by measuring response times with methane gas supplied through a calibration fixture or adaptor. Other response time tests were performed with the detector in an environmental test box. Performance was also evaluated in a full scale test gallery where face methane emission and underground ventilation were simulated. Procedures for calibration by response time measurement of the IYONI II detector have been developed. In limited testing, the IYONI II detector was found to reliably detect the presence of 1 percent by volume methane.

By S. H. Katz

Artisans and laborers in mineral industries where the air is dusty with particles of reel: are subject to a peculiar pulmonary disease known as miners' phthisis or stone cutters' consumption. In granite cutters the disease is specifically designated as granite pneumoconiosis. Very fine particles of the harder rocks are especially injurious when inhaled into the lungs. It is estimated particles about one micron (1/23000 part of an inch in diameter) are most injurious, because larger particles are more readily removed by the cilia and,wet surfaces of the respiratory passages before reaching the lungs, while smaller particles either do not readily lodge or are more easily eliminated. Silica, of which quartz and flint are composed, and which forms a large part of granite, is one of the hardest of the common rock-forming materials. It is also very insoluble when silica lodges in the lungs elimination is difficult. Rock constituents of granite other than silica are probably injurious but in a lesser degree, and this is also probably true of limestone and the softer rocks. Ultimately a worker who daily inhales much granite dust has considerable deposited in his lungs. If he continues at his trade the lung tissue becomes harder and less elastic, he finds himself short winded, and in extreme cases death may come either directly or indirectly as a result of lung failure.

Feb 1, 1921

Develop a dry dust collector suitable for working faces and belt transfer paints. Approach A filter cartridge with a reverse-pulse, self-cleaning system has been mounted in-to a low profile unit requiring electric power only. How It Works Dust-laden air entering the in-let end of the collector passes through the two inline filter elements. When the elements load to a pre-selected pres-sure drop, they are automatically pulse-cleaned by a "backflush" method using compressed air. When the elements are pulse-cleaned, caked dust material on the filter surface is released, and falls away as lumps. Dust is removed from the collector by an auger mechanism. Features of the collector are: (1) unit is completely self-contained, (2) built-in air compressor for pulse-cleaning, (3) cleaning cycle initiates automatically at a preset restriction, (4) automatic auger discharge of collected dust, (5) detachable extension auger for transporting collected dust, (6) "dust leak" indicator light, and (7) "change filter element II warning light. The collector has been designed as permissible although approval has not yet been granted.

Jan 1, 1981

By A. C. Fieldner

The Bureau of Mires in its investigations of gas masks for use in mines and allied industries has studied and developed various types of masks for protection against noxious uses and furies that may be present in atmospheres encountered in mines, metallurgical works, chemical and other industries. As a result of these investigations, the Bureau issued a schedule5 of tests under which manufacturer who voluntarily submit masks for examination and test, are issued an approval certificate for masks that meet the Bureau's specifications. In the Bureau's schedule, masks arc classified by types of gases removed, as type A masks for protection against acid gases; B; organic vapor; C, ammonia; D, carbon monoxide; E, smoke, dust, and mist; F, special gases; combination types, and type N, for protection in air against all gases, vapors, and smokes. The purpose of this paper is to describe the physical and chemical tests that were conducted on a type N mask, the protective principles and construction of the essential elements of the canister and attachments, and the uses and limitations of this type of mask. The mask tested is known as the all-service mask, manufactured by the Mine Safety Appliances Co., Pittsburgh, Pa;, and was approved (approval No. 1403) by the Bureau on July 1, 1924, for protection from all classes of poisonous vapors, gases and smokes in air.

Jan 1, 1925

By Terry J. Close

In 1992, as part of the U.S. Bureau of Mines Idaho Land Assessment Program, the Western Field Operations Center investigated the mineral resources of the 30,300-hectare Elk Summit study area. The area is in the Clearwater National Forest, adjoining the Selway-Bitterroot Wilderness in Idaho County. Idaho. The study area is underlain by granitic and metasedimentary rocks. Associated with these rocks are road metal (stone) resources, black sand mineral placer resources, and thermal water resources. Also present are abundant sand and gravel. Two of the five sites examined during the Bureau study have road metal (stone) resources, one has black sand mineral resources, one has thermal water resources. The fifth site is a black sand mineral placer occurrence. There is no evidence of petroleum or coal resources. Idaho County records indicate that 38 mining claims, mostly black-sand placer, have been located in the study area, Twenty-three of the claims are current. Workings consist of a few pits and trenches at the placer, and two borrow pits. The only mineral commodity produced from the area was about 1,500 tonnes of stone excavated from the Savage Pass and Swamp Creek borrow pits along the Elk Summit road, north of Hoodoo Lake. The stone was used to surface the road; these stone resources will continue to be used as needed.

Jan 1, 1993

By David A. Monaghan, Kenneth R. Maser, Adi R. Gurdar, D. Randolph Berry

APPENDIX B - DEVELOPMENT OF FOAM-CONCRETE SLURRY MINE SEALANT 1. Introduction This appendix describes the results of an experimental development and laboratory evaluation of foam-concrete as a rapid setting, lightweight, self-supporting mine sealant material. Foam concrete, otherwise known as Aerated Concrete, is a form of lightweight concrete whose structure consists of air bubbles held together by a hardened cement mortar. Its principal applications are found in roofing, insulation, shock absorbing, and backfill. The air bubbles in foam concrete are formed either by chemical reaction in the wet, placed mortar, or by introducing a stable foam into the mortar during mixing. The mortar is usually a cement slurry with fine sand or fly ash as filler. Our attention focused on preformed foam concrete, since this is most adaptable to field applications. Equipment is available,* which simultaneously mixes and pumps a slurry of foam concrete. Such a slurry can be produced at a rate of up to 50 yards/hr and has been pumped in a 2-inch-diameter hose 1000-feet horizontally and 250 feet vertically up without significant bubble deterioration. One very attractive feature associated with the use of foam concrete concerns site logistics. Foam concrete can be generated with densities as low as 20 lbs/ft3, and hence the total number of

Jan 1, 1973

By Larry G. Stolarczyk

1.0 FRAMEWORK FOR COMPARISON This document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system. The selected modulation process must satisfy the Bureau of Mines stated objective of improving general communications within an underground mine. The improvement being sought includes the development of a wireless communication technology of measurable benefit to both mine safety and mine productivity. The improvement will allow wireless communications paths to exist between roving miners. The wireless communication paths will also be made compatible with the existing underground telephone system to extend paging and voice communication throughout the underground mine. The new wireless equipment will include man-pack, vehicular, repeater, and base station transceivers. Repeaters and base stations will feature coupling networks for interfacing with the existing telephone circuits. Frequency modulation (FM) and single sideband (SSB) modulation processes are analyzed in view of the special conditions associated with underground mining. Of primary importance is the tremendous electrical noise generated in an operating mine that could adversely affect communications quality. High noise coupled with high attenuation rate of near field signals forces the communication system to be inherently short range. Fortunately, near field signals can propagate over great distances on underground wires and cables. The framework for comparison is generated by presenting all factors that

Reliably measure stress chan¬ges in order to assess stability of mine openings. Approach: A durable, permissible, sensor and readout system have been developed and tested. How It Works: The stress sensing element is a taut steel wire which is, vibrated at its natural frequency, If the tension on the wire is changed because of deformation of the sensor housing, the natural frequency of the wire changes. This effect is similar to decreasing or increasing the pitch of a violin string by loosening or tightening it. Because the stress sensor electrical output is a frequency signal, rather than an amplitude signal, its accuracy is unaffected by the resistance of the signal wire, or other attenuation. Signal wires can be a mile or longer without affecting accuracy. When a button is pushed on the readout box, the sensor wire is electromagnetically excited and vibrates at its natural frequency. That signal causes a readout in illuminated digits. (By referring to calibration chart and the previous reading, the user knows the change in stress.) This system is permissible. To install the sensor, a slightly oversize hole is drilled into the mine pillar. Next, a special tool is used to both position the sensor and wedge it in place. Figure 1, shows the sensor and its integral wedge and hole-fitting piece.

Jan 1, 1976