Search Documents

By J. J. Wallace

1. The Pittsburgh is the most important bed in Greene County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 6,011 million short tons as of January 1, 1954. Of this total, 5,967 million short tons is in beds 28 inches and more thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too meager to make an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1955

By A. W. Fahrenwald

The art of flotation has developed rapidly. Numerous technical staffs and individual investigators have, by their combined efforts, developed practicable methods of concentrating ores which ten or even five years ago were considered complex and impossible of commercial treatment. Also the work of those who have been engaged in pure research on the fundamentals of flotation has helped greatly to expedite the general development of the process. However, in spite of the highly successful practical operation of the flotation process, results are obtained and things happen that we are unable to explain completely, although much is known about the theory of the process. The rapid stride in flotation concentration, it is noteworthy to point out, is due to the freer exchange of facts and data by the staffs of the larger mining companies and the patent controlling corporations, and by investigators in general. Generally speaking, one may visit any mining plant and by presentation of proper credentials, be shown all that is going on or that is being done.

Jan 1, 1925

By A. K. Schellinger

1. In the United States, the industrial application of centrifugal force for separating phase constituents has been confined almost entirely to aqueous systems at room temperature. This paper presents results for experimental tests on the use of centrifugal force for separating the liquid and solid phases in molten nonferrous alloys. 2. The development and use of a small centrifuge for treating molten metals is described. The centrifugal apparatus was, in essence, a 3-inch diameter spinner pot, which revolved, within -a gas -fired furnace, at speeds up to 3,000 r.p.m.

Jan 1, 1953

By A. A. Cochran

Bureau of MinesThe Bureau of Mines studied the development of practical methods for recovering manganese from the extensive domestic resources of low-grade ores and open hearth slags. A one-step operation was developed on a laboratory scale in which manganese and iron compounds are treated with chlorine, volatilized, and separated by selective condensation. Manganese recoveries of 90 to nearly 100 percent were obtained from 9 of the most important domestic ores. Analyses of the manganese chloride product indicated that it was suit-able for aqueous electrolysis with little additional purification. A complete, integrated process that provides for the recovery and recycling of chlorine is proposed. This process appears to have distinct advantages over previously proposed manganese recovery processes, and, in sharp contrast to leaching procedures, it is applicable to practically any manganese-bearing material.

Jan 1, 1967

By John Ward Smith

The Bureau of Mines drilled Wyoming Corehole No. 1 in Sweetwater County, Wyo., to sample Green River Formation oil shale. Core obtained was assayed for oil yield to determine richness and stratigraphic distribution of oil shale in the deposit. Oil shale in place at Wyoming No. 1 site represents over 200 million barrels of oil per square mile. Additional data useful in evaluating the deposit, including generalized stratigraphy and mineralogy, detailed lithologic descriptions of the core, rock specific gravity, and bore-hole logs, are presented with the oil-yield data. The sampled Wyoming oil shale resembles Mahogany-zone oil shale in rock properties and gross mineralogy. A statistically derived equation relating shale density to oil yield for the Wyoming deposit compares with a similar relationship valid for the better known Mahogany-zone oil shales in Colorado and Utah. A density log from Wyoming Corehole No. 1 is calibrated for direct oil-yield logging. The alternating rich and lean beds of shale at this site may permit creating the permeability necessary for direct production of shale oil from the shale in place.

Jan 1, 1968

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. W. Scott

This report presents an overview of explosionproof (X-P) enclosure research being conducted by the Bureau of Mines, This report emphasizes the increasing importance of research related to the safety con- siderations of X-P enclosures used in underground coal mines. Selected topics are included that summarize results of research in the areas of electrical clearances, reliability of enclosures with windows, safety factors in X-P enclosures, potting materials, performance tests for X-P enclosures, protection against high-voltage explosions, and innovative X-P devices.

Jan 1, 1985

By Wilbur I. Duvall, Thomas C. Atchison, Joseph M. Pugliese

Short cylindrical charges were detonated in drill holes in rock to determine the effect that decoupling ( defined as the ratio of the radius of the hole to the radius of the charge ) has on the strain - generating abilities of explosions in rock . The amplitude and period of the strain pulses produced in the rock were studied as a function of distance , size of charge , and decoupling . The main results of these studies were that , for a given distance and size of charge , the amplitude of the strain pulse decreases as decoupling increases and the period of the strain pulse decreases at first and then increases as decoupling increases . A simplified theory of decoupling is presented that satisfactorily explains the experimental results . The information presented makes it possible to predict the effect of decoupling on explosiongenerated strain pulses in rock and thus helps the explosives user evaluate the effect of decoupling on his blasting .

Jan 1, 1964

By G. L. Neumann

The Andover-Sulphur Hill iron mines in Sussex County, N. J., have a production record extending over 100 years. The last production recorded was about 1880. These mines produced high-grade ore of two types: Bed ore (hematite) and blue ore (magnetite. Some sulfides (lead, zinc, and copper) were found underlying the iron deposits. Data as to size and grade of these sulfide bodies are very sketchy, Toward. J. Hewitt of Elizabeth, N. J., lessee of the Sulphur Hill mines from 194045, prospected for lead, zinc, and copper. .His Only production was several hundred tons of low-grade iron ore, which was crushed and used as heavy aggregate to make concrete blocks for ship ballast. In October and November 1942 made a magnetic survey of this area and bored six-diamond-drill holes with the dual objective of prospecting for sulfides and testing for extensions of the iron-ore deposits indicated by the magnetic survey. In 1944, an iron-mining company examined this property and diamond-drilled seven holes Between December 1949 and March 1950, the Bureau Of Mines in search of sulfide deposits, bored three additional diamond-drill holes. Two of these were on the Sulphur Hill tract and one on the adjoining Tar Hill tract.

Jan 1, 1952

By Lloyd A. Morley

Two methods are presented to determine the mechanical shaft torque as a function of time for an induction motor. The methods are based on the motor equivalent circuit and use as input variables of the motor terminal voltage, line current, input power, and power factor. One method uses all four variables and the other uses only voltage and current. The test data deals specifically with continuous miners, but the theory could be applied to other mining machines driven by multiple induction motors. Results are given for the tramming, maneuvering, cutting, and cutting with loading operations and are in the form of a minimum, a maximum, and an average of the shaft-torque time function. The theoretical development and computer implementation are discussed for both methods.

Jan 1, 1978

By J. A. Kost

Contract H0242013 was originally to evaluate through underground tests, water spray systems for controlling respirable dust at the face of a longwall plow. A number of difficulties were encountered which made such an evaluation impractical. The contract was modified to evaluate, in the BCR dust tunnel facility, the live factors believed to affect respirable dust levels. A 60-foot long; plow face mock-up was constructed in the dust tunnel, a facility with controlled airflow and dust concentration. Six types of nozzles were tested with the following parameters: two nozzle orientations, two levels of water pressure, two levels of airflow, and with and without simulated airflow through the gob. Of these factors, the most significant in reducing respirable dust levels was nozzle orientation, where the nozzle directed 45 degrees downstream resulted in 27 percent lower dust levels than those directed 45 degrees upstream (against the airflow). Following in order of effectiveness were the higher water pressure and the lower airflow. All nozzles tested resulted in similar dust reduction, i.e., the type of nozzle was the least significant factor.

Jan 1, 1979

By H. W. Kilau

Thermodynamic calculations indicate that an electrochemical cell might serve as an analytical device for determining the composition of high-purity metals. An equation, readily derived, for the cell voltage, E, is as follows: [E I RT In F NFe unknown sample T of L NFe standard] The cell, however, must come to equilibrium, must be reversible, and must have no thermal effects or complicating side reactions whose magnitude is indeterminable. This Bureau of Mines investigation explores the feasibility of an electrochemical technique for the analysis of high-purity iron. Experiments were conducted using room-temperature aqueous cells and high-temperature molten salt cells. The room-temperature cells proved to be irreversible. The high-temperature cells utilizing FeCl2 and a eutectic mixture of KC1-LiCl were reversible, but did not attain a constant voltage necessary for analytical considerations.

Jan 1, 1963

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

By J. W. Horne, W. L. Finley, A. D. Bauer, D. W. Gould

"The Bureau of Mines and the State of Colorado are cooperating in an investigation of the oil shales of Colorado. in this report the yields and the results of analyses of the oil and, gas produced from a number of oil-shale samples from the principal deposits of Colorado and other oil-shale States, are compared with samples from Scotland and Australia, where the oil-shale industry has had its greatest commercial development, and also with a sample from Brazil *here extensive oil-shale deposits are found shale samples were not selected as being representative of the different deposits, but they illustrate the wide variation in the nature of the organic matter of different oil shales.A further study is being made of the chemical composition of the shale, distribution of nitrogen and sulphur. in the products, temperatures at which organic matter decomposes, and the results will be presented in subsequent Papers, With complete data available on the chemical composition of the shales, it may be possible to explain some of the differences in the nature of the products from the various shales,Most of the work described herein was done under the supervision of M. J. Gavin. L. C. Karrick, formerly of .the Boulder laboratory, assisted in the work and gave many valuable suggestions."

May 1, 1924

By F. C. Houghten, R. R. Sayers, C. P. Yalaglou

"Introduction.Atmospheric conditions relative to high temperature and humidity are of great importance in mining, as well as in such allied fields as railroad and vehicular tunnels. An extended investigation into the effect of these factors on men has been in progress for some time, both in the field under actual working conditions, and at the Pittsburgh experiment station of the bureau in cooperation with the American Society of Heating and Ventilating Engineers and the U. S. Public Health Service.For several years one of the writers (Dr. Sayers) and L. Harrington, supervising mining engineer of the bureau, have been studying the effects of hot humid atmosphere in metal mines on the comfort and efficiency of the workers. Some of the reactions experienced in still and in moving saturated mine air at temperatures of 90 to 100°F., with men at rest are presented in a recent paper.****The present paper is based on experiments made under carefully controlled conditions to determine the relative feeling of warmth experienced by men in atmospheres of various degrees of temperature and humidity. The work was conducted by the research laboratory of the American society of Heating and Ventilating Engineers, at the Pittsburgh experiment station of the Bureau of Mines, in special physchrometric chambers built for this purpose. It was carried on under the direction of F. Paul Anderson, director of the laboratory, Dr. R. R. Sayers and A. C. Fieldner of the Bureau of Mines. The results given in this paper are for still air only. Investigations of the effects of moving air are being continued, and will be reported later."

Jan 1, 1924

By Raymond G. Travis

This paper, which describes mining methods and practices at the Hurricane Creek bauxite mine of Reynolds Mining Corp. in central Arkansas, is one of a series being prepared by the Bureau of Mines on mining methods, practices, and costs in various mining districts of the United States. The Hurricane Creek mine is in sec. 12, T. 2 S., R. 14 W., and sees. 7 and 18, T. 2 S., R. 13 W., Saline County, Ark., about 4 miles east of Bauxite. (See fig. 1.) Bauxite has been mined underground at the Hurricane Creek property since 1942. The operation is notable for relatively high recovery of bauxite under the adverse conditions of unconsolidated water-bearing overburden and unstable clay floor. Controlled caving, timbered stope walls, and efficient drainage systems on the surface and underground have minimized the problems and raised ore recovery about 25 percent above that formerly obtained.

Jan 1, 1961

By William A. Beck

"The Old Cline mine, also known as the Old Cruse mine, was first worked for gold in1895. The property was opened by several shafts and trenches; and some stoping has been done, producing several cars of copper-gold ore in the early nineteen hundreds. Chalcopyrite is visible in selected samples; and, with the aid of a mineralite, several samples showing a considerable amount of scheelite were found on the old waste dumps.The mine is in Township 6, Cabarrus County, N. C., 5 miles north of the village of Mount Pleasant, 10 miles northeast of Concord, and about one-half mile south of Watts Crossroads. It is one-fourth mile east of the county road.When examined, the property was owned by H. F. Tompkinson, Concord, N. C., and was leased, with option to buy, by L. Nash. Titles of record were not investigated.As stated above, the Cline mine was first worked in 1895. The property was Purchased in 1902 by J. A. Clark and A. A. Smith of Atlanta, Ga., and worked for gold and copper. No record is available of the quantity of ore removed during these operations.A Bureau of Mines mining engineer3/ examined the mine as, a copper prospect on October 13, 1944.The Cline mine is in an area characterized by flat to rolling topography, dissected by many streams and rivers. It lies in the Piedmont Plateau and Varies in elevation from 700 feet to 800 feet. The surrounding country is partly wooded and partly cleared farm land.A quartz vein occurs in country rock of quartzite and greenstone.4./ The ore occurs in a series of quartz lenses, having a width of 1 to 3 feet and dipping about 750 NE, and striking N. 300 W. All these lenses have fairly sharp boundaries and in some cases are entirely separated from each other, while at other times they are connected by thin stringers of quartz. They can be traced for 1,000 to 1,200 feet by a series of shafts and test pits."

Apr 1, 1946

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 E. G. Davis, H. P. LeVan, L. S. Smith

Leaching of a Georgia umber ore when using both ferrous sulfate and pickle liquor was studied in the laboratory . The ferrous sulfate content of the leach solution was the major factor affecting the extraction of manganese from the ore . Time , temperature , and the sulfuric acid content of the leach solutions had relatively little effect on leaching of manganese from the ore ; however , these factors did affect the amount of iron extracted from the umber and/or precipitated from solution . Simulated countercurrent leaching of the ore with pickle liquor containing 130 gpl (grams per liter ) ferrous sulfate ( 48 gpl ferrous iron ) produced a pregnant solution having 16 gpl manganese and 41 gpl iron . Filtration tests of the leach slurries indicated that separating the leach solution and solids by vacuum filtration was impractical , whereas pressure filtration was feasible when the cake thickness was limited to about three- fourths of an inch . Fired pellets of the filter cake yielded a firm , hard product analyzing 56 percent iron and less than 0.1 percent sulfur .

Jan 1, 1964