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By Hillary W. St. Clair

The purpose of this investigation was to determine the practicability of refining crude aluminum-silicon alloy or aluminum scrap containing silicon and iron by selective dissolution in zinc of the aluminum from the alloy followed by distillation of the zinc from the aluminum.

Jan 1, 1949

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 J. Alton Burks

When acoustical materials are used in a mining environment for noise control purposes, they are subject to environmental deterioration from hydraulic fluid, moisture, and dust. These and other factors can cause physical degradation of the material, which can lessen its ability to absorb sound. In this study, the Bureau of Mines measured the sound absorption properties of 16 different acoustical materials after 4 sample treatments: (1) being kept clean and dry (as received from the supplier), as a control or reference standard, (2) immersion in water and draining, (3) immersion in lOO-pct-petroleum-type hydraulic fluid and draining, and (4) exposure in a coal mine. The last three treatments were used to approximate the type of physical degradation that can be experienced in actual use. The impedance tube or standing wave method was used to measure the normal absorption coefficient. It was found that the absorption coefficient of most materials was adversely affected by the retention of either oil or water, with oil having the greater effect. The only class of materials that was affected by neither oil nor water was neoprene foam.

Jan 1, 1990

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 D. E. Wolfson

Twenty-two samples of West Virginia coals were carbonized at 9000 C by the Bureau of Mines-American Gas Association (BM-AGA) method, and yields of products and physical properties of cokes were determined. Eighteen samples represented the Coa1burg, No. 2 Gas, No. 2 Gas and Peerless, Powellton, Eagle, Big Eagle, Lower Eagle, Sewell, Fire Creek, and Pocahontas No.6 beds in Fayette County, and four samples represented the Sewell and Fire Creek beds in Greenbrier County. Expansion characteristics of the majority of samples were determined in the Bureau of Mines sole-heated oven. Chemical analyses were determined for all coals. The coals in Fayette County are high-volatile A, medium-volatile, and low-volatile in rank, and the Greenbrier coals are medium-volatile in rank. Most of the coals are chemically suitable for metallurgical coking. All coke strength indices are within acceptable limits for metallurgical coking coals. All the high-volatile A coals contracted and the medium-and low-volatile coals expanded in the sole-heated oven expansion test.

Jan 1, 1966

By Benjamin W. Haynes

This research was conducted as part of the U.S. Department of the Interior, Bureau of Mines program to recover metals, glass, and a combustible fraction from municipal solid waste (MSW). The objective of this analytical study was to determine the concentration of antimony, arsenic, and mercury in samples taken from various sampling areas in the Bureau of Mines raw refuse recycling plant and to compare these values with those for coals used in the generation of electricity. To provide the necessary analytical data, sensitive reproducible ashing-chemical digestion-atomic absorption procedures were adapted from published procedures. It was determined that antimony and mercury concentrations in the combustible fraction of MSW are approximately an order of magnitude higher than those found in coals presently used for power generation;' the arsenic concentration is similar in both fuels.

Jan 1, 1978

By J. G. Schoning

The Holmes Safety Association is an offspring of the Joseph A. Holmes Safety Association which was organized in Washington, D. C., in 1916 at a meeting of representatives of twenty-four leading mining associations connected with every branch of the United States mineral industries. The purpose of the meeting was to do honor to the memory of Joseph A. Holmes, one of the founders of the United States Bureau of Mines and its first director, whose death had occurred the year before on July 12, 1915. In deference to what was believed would have been the expressed wish of this great humanitarian and benefactor of the mineral industries, it was decided to establish a national safety organization to cover the mineral indus¬tries exclusively; out of respect for his memory and service, the organization was named the Joseph A. Holmes Safety Association. On receiving requests from several mining districts, in 1922 a number of chapters ware established in several mining States.

Jan 1, 1929

By Gus Pantages, Bernard D. Blaustein, Charles Zahn, Irving Wender

Oils from coal hydrogenation have been examined at the Bureau of Mines to learn whether any centers of the optical activity reported in coal would survive catalytic hydrogenation at 450-525 ° C and about 8,000 psig pressure , and , if so , to obtain information about the nature of the active products . Oils from carbonization tars also were examined . Optical activity was found in the majority of the distillate fractions of the hydrogenation oils and in almost all distillates from the carbonization tars . No activity was observed in the tar - acid and tar - base fractions examined . Methods for isolating optically active concentrates included distillation through a packed column , liquid chromatography on silica gel , and adduction with urea . For the materials so processed , the optical activity segregated mainly in the paraffin - naphthenic and the hydroaromatic fractions . Although the specific compounds responsible for the optical activity were not isolated , experimental and spectrometric findings indicate that alkylsubstituted cycloalkane , cycloalkene , and hydroaromatic structures are most likely responsible for the optical activity of the concentrates . The optically active centers probably derived mainly from the steroids and terpenes in the biological materials that participated in the formation of coal .

Jan 1, 1964

By Xavier B. Starnes

"SUMMARYThe J. D. Price property is in Crittenden County, Ky., about 5-1/2 miles west of Marion. The Levias-Crittenden Springs fault system traverses the property. Mines on 3 miles of the same fault system immediately northeast have produced about 250,000 tons of fluorspar ore. The Keystone property, adjacent on the northeast, has produced about 150,000 tons of ore. 3/About 1934, lessees, sank a shaft upon the Price property to a depth of 111.5 feet and crosscut from the bottom of the shaft to the principal fault. No ore was found. Later, in 1942-43, they explored the same fault by core-drilling, but this project also was unsuccessful in finding ore.The author visited the property in September 1944, and subsequently the Bureau further explored the property by core-drilling three holes. No ore was found.ACKNOWLEGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective 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. This ex¬ploratory project was under the general supervision of E. D. Gardner, regional engineer of the Central Region, and 0. M. Bishop, district engineer, Bureau of Mines. The mining branch is under the direction of L. B. Moon. The work on the project was under the direct supervision of Xavier B. Starnes, mining engineer."

Jun 1, 1947

By G. W. Elger

The Bureau of Mines conducted laboratory and larger scale studies on samples of domestic perovskite and ilmenite ore concentrates to devise a procedure for recovering TiC from these ores. From the concentrates, mixtures of titanium and calcium carbides were produced. The carbides were then ground and reacted with water. This reaction decomposed the CaC2 to acetylene and hydrated lime and simultaneously liberated the TiC. Using a combination of elutriation and gravity-separation techniques to separate the hydrated lime, approximately 93 pct of the titanium was subsequently recovered as purified carbide containing 54 to 70 pct titanium with CaO content as low as 0,6 pct. This combination of techniques can be used to separate more than 90 pct of the CaO from the TiC. Therefore, this carbiding procedure is a viable method for treating titaniferous materials, including perovskite, that contain more than 20 pct CaO. Tests made in a static-bed reactor showed that for the reaction of TiC with elemental chlorine to produce titanium tetrachloride (TiCI4), a temperature of at least 940° F is desirable to achieve a suitable extraction of titanium in a laboratory chlorination reactor. In fluidized-bed tests at 840° F, 98 pct of the titanium contained in TiC was extracted.

Jan 1, 1980

In this U.S. Bureau of Mines report, two drill-split mechanical excavation mining system concepts are described, casted, and cost compared with conventional drill-blast mining systems. The concepts for the two drill-split mechanical excavation mining systems presented are (1) a method for steeply dipping narrow veins 0.6 to 1.2 m wide and (2) a longwall method for fiat-lying tabular ores. In the proposed systems, 70 to 80 pet of the ore is disposed of underground as backfill. For sortable ores, face area crushing, sorting, and direct stowage of run-of-mine waste and low-grade ores are proposed. The underground sorting and stowing of waste reduce materials handling, processing, and waste disposal costs by reducing the quality of ore transported to the surface by 70 to 80 pet (by volume). Because many of the tools and techniques proposed for use in these systems have little or no historical mining industry use, cost assignations are heavily influenced by engineering judgments and presented as prefeasibility-level cost estimates. These estimates, presented as discounted-cash-flow-rate-of-return (DCFROR) values, show the proposed systems to be at least as profitable as, and in some cases 50 pet more profitable than, conventional drill-blast mining.

Jan 1, 1994

By R. V. Lundquist

The compound 2Na2O?3CaO?5Al2O3 occurs as a minor phase in lime-soda sinters prepared for extracting aluminum from siliceous aluminum-bearing materials. About 99 percent extraction of sodium and aluminum from synthesized 2Na2O.3CaO.5Al2O3 was obtained in solutions of NaOH-Na2CO3 at leaching temperatures of 50° C and above. Extractions in water were low because insufficient NaOH was generated by hydrolysis. Extractions in NaOH solutions were limited to about 80 percent owing to the precipitation of hydrated calcium aluminates. Rapid extractions of 100 percent were obtainable in NaaC03 solutions, but the subsequent rapid precipitation of alumina trihydrate caused losses in alumina recovery.

Jan 1, 1965

By W. R. K. Wu

This Bureau of Mines report presents a statistical study of the repeat abilities of coal-plasticity parameters obtained in the tests with the Gieseler plastometer and the Audibert-Arnu and Hoffmann dilatometers. Repeatability is expressed in terms of one or two standard deviations for the differences between duplicates. The statistical method employed here is summarized. Results are tabulated for the temperature and nontemperature parameters of the three tests.

Jan 1, 1970

By Martin H. Rogoff

The presence of antibiotic materials extractable with polar organic solvents was demonstrated in coals of various ranks. Since these antibiotics occur in low concentrations, 200 pounds of a high-volatile C coal was extracted with acetone at room temperature to obtain sufficient material for detailed study. The biologically active materials in the extract were concentrated by extracting with aqueous sodium hydroxide. The fractions soluble in sodium hydroxide inhibited bacterial cultures when present in concentrations comparable to those at which other antibiotics are active (5 µg/ml). Steam distillation of the extracts did not yield highly active materials, contrary to the finds of other investigators. Mass spectrometry of the extract indicated, mainly, the presence of 6-ring compounds in the region of mass 324 to 392. The predominance of 3-ring aromatic systems found by ultraviolet analysis suggests compounds such as biphenanthryl or similar structures. The activity of the hydroxide- soluble material decreased markedly when the phenolic hydroxyl groups were transformed into trimethylsilyl ethers. Hydrolysis of the ethers yielded a product having the same activity as the original material, which indicates that phenolic compounds are largely responsible for the antibiotic activity observed.

Jan 1, 1963

By A. W. Fahrenwald

The purpose of screening is to separate a crushed or natural product into one or more products in which size of grain is constant, or within certain size limits. The ore dresser finds need for this operation in the laboratory, in the study of ore-dressing processes, and for various purposes in the plants. In the plant, for example, screens are employed in closed circuit with crushing devices such as rolls, and sometimes are used in closed circuit with ball mills. Screens are generally used to prepare jig feed where a sized feed is wanted. For any given sieve opening there is in any feed a certain percentage of grains that will pass through the sieve meshes only with difficulty and under favorable conditions. For example, cylindrical grains of length greater than the maximum dimension of the sieve mesh and of diameter less than the sieve opening pass the sieve only when the long axis of the grain is normal or nearly normal to the sieve. Whether such grains should actually be in the through's or the oversize of a screening operation--considered from the point of view of the subsequent treatment of the grains--can not be said. The grains that pass the sieve opening in a screening process only under-favorable conditions have been named "difficult" grains by R. K. Warner.4 In many ore-dressing flow-sheets it probably matters little whether these difficult grains show up in the screen through's or oversize. The main objection to them is that they are sieve-blinding.

Jan 1, 1929

By Henry E. Blake

The Bureau of Mines has been engaged in a continuing research effort to develop processes for increasing the recovery and utilization of fluorine from low-grade resources. This current research has shown that over 98 percent of the fluorine in phosphate rock is extracted when the ore is treated with excess phosphoric acid in the presence of water vapor at 150° to 180° C. More than 80 percent of the fluorine can be recovered as fluosilicic acid, which can then be converted to commercially useful hydrogen fluoride or fluorspar by previously developed Bureau processes. Extraction of P205 from the ore was about 98 percent in batch tests and 90 percent in semicyclic tests.

Jan 1, 1974

By W. H. Forbes

The prevention of accidents from falls of roof and coal requires a considerable amount of personal judgment , for conditions are different even in adjoining working places in the same mine , and conditions may change from hour to hour even in the same working place as the coal is shot down and loaded . Experience has shown that many men can not or do not exercise enough care to protect themselves from injuries ; moreover , where the foremen have been made directly responsible for the safety of the men under them , accidents from falls of roof and coal have , in many instances , been reduced as much as 50 per cent . There is now no question that careful , constant , and intensive supervision is essential in preventing acci- { dents and more especially accidents of this class . Falls of roof and of coal account for approximately 50 per cent of all coal mine accidents and annually result in the death of approximately 1,000 men and cause lost - time injury to approximately 50,000 men . These and other accidents are recurring with little or no diminution , usually not because of the lack of knowledge of safe and dangerous practices , or of the technique of safety , but largely because of the lukewarm interest of major executives in safety or the failure of mine officials to formulate and to enforce common - sense rules and regulations . When failure is the outcome of a sincere attempt of the managing officials to teach safety to the miner , the fault may usually be attributed to misguided effort . Various solutions for the problem of eliminating accidents from falls of roof or coal have been suggested , some of which are : Standard system of timbering for the specified mining districts ; departure from the room-and - pillar system to a more concentrated system of mining ; more intensive supervision - that is , 1 section foreman for every 25 loaders instead of 1 section foreman for 75 , 80 , or even more loaders the practice in most mining districts . - However , investigations conducted by the writer at numerous mines operated by a number of mining companies in several districts show that employees and officials alike are inclined to work under loose and unsupported roof , relying solely on the " drummy " sound and on their judgment and experience as to whether the roof will stay in place for one hour or for several hours . With but few exceptions , men who had been injured by falls of roof or ccal or were found working under loose and unsupported roof , admitted that they knew of the possibly unsafe condition , but it was their opinion that the roof or coal was not loose enough to fall for some time .

May 1, 1931

By D. J. Bauer

This report covers a phase of an extraction project carried out as part of a research program on rare-earth technology. The current project--the production of pure cerium compounds--is an intermediate step between ore processing and metal reduction. In this connection, a study on a separatory-funne1 scale was made on nonreducing extractants for recovering cerium (IV) from tri-n-butyl phosphate (TBP) and of methods for recovering the cerium nitrate from the strip solution. Dilute sulfuric acid was found to be 100 percent effective in stripping cerium (IV). Several precipitants were effective in recovering the cerium from the strip solution, and ethanol was especially promising. A scaled-up investigation was made into the use of spray-tower type equipment to perform the function of extracting, washing, and stripping. This equipment, referred to as the pressure-bubbler, utilized the system developed on the separatory-funnel scale. Feed solutions were prepared from a bastnasite concentrate by two techniques. Of these, the sulfated bastnasite solution was most successful, resulting in 86-percent recovery of the cerium at 99.7+-percent purity.

Jan 1, 1959

By E. W. Dean

A previous report of the Bureau of Mines* has supplied data for the physical and chemical properties of samples of crude petroleum produced in the eastern fields of the United States. It was issued as a preliminary chapter of a bulletin which is to cover the results of a survey of the entire country. The present report is a second preliminary chapter including figures that are available for the producing fields of the Rocky Mountain district. Work is being continued. with a series of samples from the States of Kansas and Oklahoma which will be described in a third preliminary chapter, to appear at a subsequent date. Acknowledgments. The obtaining of samples was rendered possible through the courtesy of representatives of a number of producing and refining companies operating in the Rocky Mountain district. The Bureau hereby acknowledges its appreciation of the hearty spirit of cooperation that was universally encountered.

Jan 1, 1921

By D. W. Frommer, L. Bonicatto, M. M. Fine

A mineral - dressing investigation was conducted to demonstrate the ability of an anionic silica - flotation process to produce high- grade concentrates from submarginal iron ores of the western Mesabi and Menominee ranges . Commercially available equipment and reagents were used . Samples from the Menominee range were exclusively from the Groveland , Mich . , mine and contained hematite as the chief iron - bearing mineral . Bench- scale investigations established that the anionic silica flotation method can function effectively on a variety of undeslimed ores . Continuous tests completed on one Mesabi semitaconite ore and on Groveland mill feed , have verified the validity of the bench research . The Mesabi samples yielded a concentrate containing 60.3 percent Fe and 6.0 percent Sio with an accompanying iron unit recovery at 90.5 percent . Iron recoveries from the mill feed ranged from 79.0 to 87.4 percent .

Jan 1, 1964