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By Walter R. Storms

The Iron Mountain tungsten deposits first were visited by a field party of the Federal Geological Survey in May 1942 while beryllium deposits in that district' were being examined . Later they were examined by F. A. Rutledge , an engineer of the Bureau of Mines , and an exploration project was recommended , work upon which began in March 1943 and was terminated in April 1943 after intensive trenching and sampling had been completed .

Mar 1, 1947

By R. V. Ramani, W. Miola, R. Srikanth, S. C. Soboleski

"Dust control in high-production longwalls requires attention to operating practices and ventilation schemes. Several studies have shown that the shearer is the major source of dust on a longwall face. Support movement has not been regarded as a major source of dust in US longwalls. Yet, under certain conditions, 31% of the shearer operator's dust exposure can be due to support movement.Several methods have been developed for the control of shield-generated dust. But the need for better methods is apparent. In this paper, the amount of airborne, respirable dust generated per shield move is estimated from specially designed experiments on longwall faces. Ten experiments were conducted on five longwall faces in four mines. Each experiment involved one face visit and lasted three to six hours. The contribution of shield movement to the airborne, respirable dust concentration immediately downwind of the shield move varied between 0.12 and 1.75 mg/m3 in the five longwall faces. The mass of airborne, respirable dust gener-ated by shield movement was found to vary between 39 and 386 mg per shield move. The results from this study reveal that control of dust from longwall shields requires a combi-nation of approaches involving alternative operating prac-tices, reducing shield dust generation rate, increasing face air flow and decreasing personnel exposure.IntroductionIn 1992, longwall mining accounted for about 36% of US underground coal production, a 240% increase from a decade ago. The absolute longwall tonnages were 46 and 133 Mt (51 and 146 million st), respectively. Compared with room-and¬pillar mining systems, the longwall mining system is charac¬terized by higher recovery, enhanced safety and higher pro¬ductivity.However, personnel dust exposure on a longwall face is higher than in other types of mining. According to Mine Safety and Health Administration (MSHA) data, fewer longwalls were in continuous compliance with the applicable dust standard in 1992 than in 1989.Controlling shearer-generated dust and reduction of per-sonnel exposure to airborne dust have commanded attention in the design of longwall faces, operational practices and ventilation schemes. Studies in the United States and abroad have revealed that support-generated dust can be a major obstacle to compliance under certain conditions (Becker et al., 1989; Bradley et al., 1983; Jankowski and Organiscak, 1983; Jankowski et al., 1990; Organiscak et al., 1985)."

Dec 1, 1996

By D. P. Desmond

The U.S. Bureau of Mines investigated leaching automobile catalysts with sodium cyanide (NaCN) solutions at high temperatures to recover platinum-group metals (PGM). The feed was virgin monolith rejects, used monolith, and used pellet catalysts. Leaching with a 5-pct NaCN solution for 1 h at 160° C dissolved over 97 pct of the PGM in the virgin monolith, over 85 pct of the PGM in the used monolith, and over 90 pct of the PGM in the used pellet catalyst. Over 99.8 pct of the dissolved PGM was recovered as a precipitate by heating the solution to 250° C for 1 h in an autoclave. The cyanide complexes were decomposed, and free cyanide was destroyed.

Jan 1, 2010

By L. D. Stewart

The main reasons for developing an induction system for signaling from the cage are, first, to increase safety, and second, to effect economies in the operation of cage and ship hoists, especially when work is being done in the shaft. To-day nearly all mines which employ safe methods have installed safety gates on cages, at the different levels, and at the collar of the shaft. Under the old system in some instances signals could only be Given from the station outside the cage, and in other cases, after the signal was given the only method whereby those riding on the cage could control its movements consisted of pulling the bell-rope hanging in the shaft, an uncertain and somewhat hazardous procedure at best. With the system herein described, however, it is possible, without opening the gates, to signal to the engineer from any place in the shaft whether or not the cage is moving, and finder the same conditions it is possible to converse with the engineer by using the telephone. In short, the cage tender has at all times an opportunity either to signal or talk to the engineer without leaving the cage.

Jan 1, 1931

By Walter D. Holland

LFE Environmental performed an Industrial Hygiene survey of the Paraho Oil Shale Mining and Processing facility in Anvil Points near Rifle, Colorado, on August 6 and 7, 1975. This survey consisted of an investigation of the underground operations for diesel emission contaminants and of the above ground work areas for all inhalation contaminants other than silica dust. Samples were collected to investigate the following contaminants: respirable dust, total dust, NO2, NO, H2SO4, formaldehyde, CO2, S02 and CO. None of the determinations of contaminants in the underground operations indicate air concentrations exceeding their standards. The results for the samples collected above ground indicate only one operation where the employee's exposure exceeds the standards. It is a welding operation where the standards for total dust and lead are exceeded. Since the survey the employer has installed an exhaust ventilation system which has significantly reduced the welder's exposure.

Jan 1, 1976

By G. St. J. Perrott

Through the development of manufacturing processes whereby ethylene glycol can be made on a large scale; ethylene glycol dinitrate is now being used in high explosives (dynamites and permissible explosives) by some manufacturers as a low-freezing ingredient of the "explosive oil" instead of such compounds as nitropolyglycerin and nitrosubstitution compounds. The amount of ethylene glycol dinitrate being used constitutes 25 to 50 per cent of the oil. The purpose of this report is to give the results of toots, to determine the effect on the safety and physical properties of permissible explosives of subsituating 25 peg cent of ethylene glycol dinitrate for an equal amount of nitroglycerin or a mixture of nitroglycerin and nitropolglycerin.

Jan 1, 1929

By Martin H. Stanczyk

Acid leaching of selected copper sulfide minerals, impure copper sulfide flotation concentrates, and a cement copper precipitate at elevated temperatures and pressures was investigated. Copper extractions of 97 to 99 pct were obtained by leaching chalcopyrite and the flotation concentrates with water under oxidizing conditions at 200° C for 30 to 60 min. In tests with bornite, chalcocite,and cement copper, addition of sulfuric acid or pyrite to the autoclave was required to obtain similar copper extractions. The chemistry of leaching copper minerals was studied. It was determined that different copper sulfides altered to covellite as one step in their dissolution.

Jan 1, 1963

By D. A. Reynolds, J. D. Davis

During early development of the blast furnace, Connellsville coke made entirely from Pittsburgh-bed coal proved to be an excellent fuel. The need for blending coking coals arose as the industry grew and it became necessary to carbonize coals having voking properties inferior to those of Pittsburgh coal Most coals carbonized today in continental Europe and this country are blonded: This practise has improved the quality of coke and permitted the utilization of coals that would yield inferior coke, if carbonized sepa- rately, The depletion of the world's better coking coals, which has been noted by leading coal technologists,2/4/wes accelerated during the recent war and. It is important, therefore, that reserves be evaluated and conserved. In the principal, steel-producing sections of this country, Pocahontas coals have been blended so extensively that the terms "low-volatile coking coal": and. "Pocahontas" have become virtually synonymous. Other low-volatile coals. have been used to manufacture metallurgical coke and will be used more extensively as, the supply of the better known and more accessible Pocahontas coals decreases. Recognizing the need for augmenting the supply of high-rank coking coals, the Bureau of Mines has included both low- and medium-volatile coals in its Survey of the Carbonizing Properties of American Coals, which was started with the cooperation of the American Gas Association in 1929. Twenty coals, 12 of low-volatile and 8 of medium-volatile rank, have been blended with high-volatile A Pittsburgh-bed coal, and five standard low- volatile coals have been blended with various high-volatile coals. Most of the results of carbonization tests of these coals and their blends have been

May 1, 1946

By A. Adams

The quality of hafnium metal produced by the Kroll process depends upon the purity of the hafnium tetrachloride. This investigation of methods for purification of hafnium tetrachloride was undertaken to aid in producing a higher purity hafnium metal than is currently produced by the Kroll process, The quantities of metallic impurities in hafnium metal were decreased by contact with molten alkali-metal chloride salt. Contact was achieved by a semicontinuous process of bubbling gaseous hafnium tetrachloride through a molten salt bath or by a batch process, first fusing the tetrachloride with a combination of alkali chlorides and then heating the mixture to sublime the hafnium tetrachloride. Low-melting mixtures of sodium, potassium, and lithium chlorides were used to purify hafnium tetrachloride. About 30 percent of the initial hafnium tetrachloride was trapped during purification with alkali- metal chloride salts. The 95-percent confidence limits (6)4 for the amount of oxygen decrease 60 and 34.3 parts per million when the batch purification is combined with a reduction so that both take place in the same equipment,

Jan 1, 1961

By C. A. Pearson, W. D. Dietzman, M. E. Hawkins

Results of chemical analyses and electrical resistivity measurements of 422 samples of oilfield brines from 120 east Texas fields in Railroad Commission of Texas Districts 5 and 6 are presented in tabular form . These samples represent water from all of the major petroleum- productive formations in the area . Water analyses and electrical resistivity data , when fully utilized by proper study techniques , are useful tools in the solution of many engineering problems such as detection of well leaks , identification of water sources , and interpretation of electrical well logs . In the area included in this study , these representative data should facilitate the solution of problems in which water analysis and water resistivity are factors .

Jan 1, 1964

By Joseph S. Coffman

The Bureau of Mines investigated the availability of barite (BaSO4) from 35 U.S. and 41 non-U.S. mines and deposits in 17 market economy countries (MEC's). This evaluation assesses the availability of mud-grade barite, and concentrates consumed by the chemicals and fillers industries. The demonstrated resources defined in this analysis totaled 130 million metric tons (Mmt) of barite (contained BaSO4), yielding a potential 115 Mmt of recoverable barite concentrates. At the 1984 MEC production rate, the evaluated resources would last about 30 yr; however, this would include production costs of up to $100/mt concentrate. An average price needed to cover all costs of production over the life of each operation was determined for both mud-grade and chemical- and filler-grade barite products. Including a 0-pct discounted-cash-flow rate of return (DCFROR), regional weighted- average total production cost ranged from $38/mt for barite concentrates in Asia to $71/mt for U.S. operations. Transportation costs have the greatest impact, contributing up to 60 pct of the total cost of production. Rail transportation costs from the mines to U.S. markets are generally significantly higher than ocean shipping rates on imports.

Jan 1, 1986

By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By J. L. Ambs

The U.S. Bureau of Mines (USBM) Diesel Research Program emphasizes the development and evaluation of emission control devices to reduce exposure of miners to diesel exhaust pollutants. Studies by the USBM have shown that diesel exhaust aerosol (DEA) contributes a substantial portion of the respirable aerosol in underground coal mines using diesel equipment not equipped with emission controls. The USBM and the Donaldson Co., Inc., Minneapolis, MN, have developed a low-temperature, disposable diesel exhaust filter (DDEF) for use on permissible diesel haulage vehicles equipped with waterbath exhaust conditioners. These were evaluated in three underground, mines, to determine their effectiveness in reducing DEA concentrations. The DDEF reduced DEA concentrations from 70 to 90 pct at these mines. The usable life of the filter ranged from 10 to 32 h, depending on factors that affect DEA output, such 'as mine altitude, engine type, and duty-cycle. Cost per filter is approximately $40.

Jan 1, 2010

By R. R. Brown

The Bureau of Mines undertook a limited feasibility study to determine the practicality of removing copper from automobile scrap by thermal treatment. Test specimens, prepared by wrapping bare and insulated copper wire around small steel coupons, were heated at 600° to 1,150° C in various atmospheres for different lengths of time under both static and dynamic conditions. The tests indicated that adequate removal of copper cannot be effected by thermal treatment of scrap above the melting point of copper. Tests showed that copper present in scrap as insulated wire is embrittled by thermal treatment at 800° to 900° C if the insulation contains lead, and that the embrittled copper is almost completely removed by a mechanical action such as tumbling. Also chemical pretreatment of specimens to effect embrittlement of copper and the magnetic separation of oxide scale were studied. Tests showed that bare copper can be embrittled by depositing waterglass (Na, Si409) on copper prior to thermal treatment.

Jan 1, 1968

By William W. Elmer

This paper, describing the mining method at the Black Butte quicksilver mine, is one of a series of papers being prepared by the U. S. Bureau of Mines on mining practices, methods, and costs in the various districts of the United States. It is presented to show the mining practice and costs in the successful treatment of low-grade quicksilver deposits. The operation discussed is an excellent example of w1-pat can be done in working a limited tonnage of low-grade ore under sound management. The Black Butte mine is situated at Black Butte, Lane County, in the southern part of the State of Oregon, 17-1/2 miles from Cottage Grove -- a station on the Siskiyou branch of the Southern Pacific Co. The Black Butte mining district lies in the foothills of the Calapooia Mountain Range, which connects with the Cascade Range on the east and with the Coast Range on the west. The elevation at '.lie reduction plant is 1,000 feet above sea level. The apex of Black Butte Mountain, or which the mine is situated, has an elevation of 2,700 feet. The district possesses exceptional natural facilities infrequently met with elsewhere for the mining and reduction of cinnabar ores. Several factors which contribute to the unusually low mining costs are:

Jan 1, 1930

By Maria I. De Rosa

Table 55 and figure 19 show the number of fires and fire injuries for stone mills by state during 1990-2001. Table 55 also shows the injury risk rates, employees' working hours, and lost workdays. In all, 118 fires occurred in 33 states. Seventy-six of the fires caused 82 injuries (including 8 fires and 6 injuries involving contractors). The yearly average was 9.8 fires and 6.8 injuries. The Ewhr value was 873 x 106 hr (In = 0.019), and the LWD value was 1,911. Missouri had the most fires (16 fires and 9 injuries), followed by Pennsylvania (15 fires and 14 injuries), Michigan (9 fires and 5 injuries), and Virginia (7 fires and 5 injuries). Of these states, Virginia had the highest injury risk rate value (In = 0.09 1). Table 56, partly illustrated in figure 20, shows the number of fires, fire injuries, risk rates, employees' working hours, and lost workdays by time period. The number of fires and fire injuries decreased during most of the periods, with a sharp increase during the last period. The number of employees' working hours increased throughout the periods. The In values follow patterns similar to those shown by the injury values. Tables 57-63 show the number of fires by ignition source, method of detection and suppression, equipment involved, location, and burning material by time period. Figure 21 shows the major variables related to fires for 1990-2001. Table 63 shows the fire injuries per number of fires causing injuries and total fires by year, ignition source, equipment involved, and location.

Jan 1, 2004

By R. V. Ramani, V. T. Burgos, J. A. McClay

Model testing is a two part operation; first, to assure the valid¬ity of the mathematical statements and second, to evaluate the accuracy of the computer model for predictive purposes. Verification of both the conceptual and computational aspects can be achieved through the use of input data for which output results are available for comparison. In this dissertation, two test problems were selected for model testing from the Economic Evaluation Reports of the U.S. Bureau of Mines, Process Evaluation Group. Verification Data Set I Input data for this test was selected from an economic analysis of a hypothetical 1,056,000-ton-per-year mine in a 48-inch bituminous coal seam (Process Evaluation Group-Report No. 72-27, 1972). The mine was scheduled to operate five days per week, three shifts per day, 220 days per year with an estimated life of 20 years. Coal reserves covered an area of 6.4 square miles with an expected recovery rate of 70%. Production was achieved through 4 continuous miner sections with an average production rate of 400 tons per shift. The cost summary in the report included a breakdown of equipment and labor requirements. A depreciation schedule listed the expected capital expense per year of operation, assuming capital replacement with identical units and no change in the unit cost. Supply and oper¬ating costs were listed in both gross annual figures and cost per ton of production. The operating and investment costs were projected over the 20 year mine life and a discounted cash flow analysis performed to determine

Jan 1, 1975

By Richard O. Kneisley

An empirical method, based on U. S. Bureau of Mines field studies in several Western U.S. coal mines, is presented for sizing gate road yield pillars. Discriminant analysis was used to generate functions separating successful from unsuccessful case studies. These functions relate the pillar width-height and extraction ratios and a pillar development factor to the Coal Mine Roof Rating System (CMRR), and are assumed to establish three criteria that other entry systems, under similar conditions, must satisfy. A program, Pillar Sizer, from user-provided inputs, generates a range of pillar sizes that meets the proposed criteria. Although the analysis is based on a sample consisting primarily of two-entry systems, the derived expressions generate pillar sizes closely agreeing with observed, two-entry and three-entry in situ pillars. It is concluded that the proposed approach should assist mine operators estimate entry system yield pillar dimensions.

Jan 1, 2010

By D. J. MacDonald

This U.S. Bureau of Mines report reviews published information on synthetic berlinite (AlP04) and suggests experimental conditions requisite for its production. Berlinite is a piezoelectric material with potential use as a substitute for quartz in the crystal oscillators, which are components of electronic and electroacoustic equipment. Information gathered here (mostly from published sources) includes historical background, physical properties, end-use applications, criteria of quality, and physio-chemical factors involved in berlinite crystal growth. It is concluded that growing large high-quality berlinite crystal would require high-purity starting materials in an autoclave equipped with a noncorrodible liner and operated with temperature control of ±O.OO5 ac over a range of 250 to 350 ac.

Jan 1, 1995

By Lee M. Manna

Approximately 10,000, 10-Ton, 4 wheel, 2 truck, coal mine cars are in general service in U. S. Mines. None are equipped with an automatic braking system. Very few are equipped with hand or parking brakes. The report lists major manufacturers of the car and develops estimate as the percentage represented. It complies physical specification of cars of major car manufacturers, and develops a composite clearance diagram. It then discusses a pneumatic system employing truck components for an automatic system that could be used as an add-on unit. The components are listed and priced and a schematic circuit is developed for the system. Recommendations as to future programming are made.

Jan 1, 1976