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By James R. Boyle

The mining methods and practices used at the Young zinc mine, American Zinc Co. of Tennessee, have resulted in a low-cost, high-yield operation. Zinc ore (sphalerite) occurs in limestone-dolomite beds of the Kingsport Formation and is mined by modified room and pillar method. Utilizing trackless mining equipment which incorporates a high degree of flexibility, this operation has had a steady increase in productivity.

Jan 1, 1965

By Sidney Katell

This study presents the economics of the hot-carbonate purification process for removing C02. It considers three variations of the process in order to meet the design specifications, which call for a feed-gas flow of 10 million standard cubic feet per hour (std.c.f.h.) with C02 inlet concentrations of 10, 20, and 30 percent and exit C02 values of 5, 2, 1, 0.5, and 0.1 percent. Inlet pressure and temperature are 350 pounds per square inch [e] (p.s.i.g.) and 300° F., respectively. Estimated capital and operating costs are shown in the following to tabulations: [ ]

Jan 1, 1960

By R. D. Berkenkotter

This report describes a weighted method for evaluating the mean and variance of assay data from samples of different length . The method , which produces unbiased estimates from which valid confidence limits can be computed , is appropriate for bedded deposits of variable bed thickness and for vein deposits of variable vein width . Assay data from the bedded Florida phosphate deposit is used to illustrate the procedure .

Jan 1, 1964

By H. W. C. Prommel

The increase in the price of gold in 1933 was the cause of starting many activities in gold prospecting and mining; it led to investigations of many of the so-called desert placers in the Southwest, which heretofore had not been deemed of commercial importance. Among these, attention was called to some of the gravel beds in the vicinity of the Randsburg-Atolia mining districts of Kern and San Bernardino Counties, Calif., in which gold and scheelite, (calcium tungstate, CaW04) were said to be present. Following a partial sampling and testing of the gravel, large-scale operations were begun in 1935. During the same year more detailed sampling and testing of the gravel beds were done by the author. During 147 days, 1,239 test holes 28 inches in diameter were drilled; their total depth amounted to 16,705 feet. These test holes furnished 2,495 samples of an average volume of 1.0583 cubic yards bank run each; all of the material was run through a sample mill constructed on the property. Original and rather unusual sampling and testing methods had to be used; milling and mining methods for large-scale operations also offered difficulties. The primary purpose of this drilling and sampling campaign was to determine, over a large area, the amounts of gold and scheelite recovered by placer methods such as were already in use on the property. This paper describes sampling and testing methods employed by the author during the 1935 drilling campaign. LOCATION The gold and scheelite placer deposit is in the Atolia tungsten mining district about one-half mile west of the small mining town of Atolia and about 5 miles south of Randsburg in the Randsburg gold-mining district. The deposit lies near the foot of the Rand Hills, in the Mojave desert. The territory is served by hard-surfaced roads from the north and south; Los Angeles is 150 miles to the southwest. A branch of the Southern Pacific Railroad passes within 5 miles of Randsburg.

Jan 1, 1937

By Raymond O. Dannenberg

The Bureau of Mines conducted laboratory and full-scale tests to develop a process for improving the flotation characteristics of lime-treated waste water produced by the Kennecott Copper Corp., Magna, UT. Unknown substances in the waste water reduced the flotation efficiency of the metal sulfides. An estimated annual loss of 795,000 lb Cu, 232,000 lb Mo, 5,625 tr oz Ag, and 617 tr oz Au would result from recycling the total flow from the lime treatment plant to the flotation mill in an effort to conserve water and reduce associated expense. The tests indicated that aeration or treatment with activated carbon significantly improved the water quality. The improvements in molybdenum recovery averaged 8 pct for carbon, 11 pet for activated carbon, and 16 pct for combined aeration and activated carbon. The combination of the two processes produced water quality as good as or better than normal feed water.

Jan 1, 2011

By W. E. Robinson

Samples of raw oil shale and kerogen concentrates were oxidized by alkaline potassium permanganate, air, nitric acid, oxygen, and ozone to obtain information about the chemical structure of organic kerogen in oil shale. In one test, oil shale and oil-shale products were oxidized exhaustively with alkaline potassium permanganate, and the distribution of the organic carbon in the final oxidation products was determined. Comparing results of this oxidation with those obtained from other carbonaceous materials and known compounds gave information about the structure of kerogen. Alkaline potassium permanganate oxidation also was used partly to degrade kerogen into soluble products for characterization purposes. Structures present in these degradation products were indicative of type structures originally present in the kerogen. Nitric acid, oxygen, and ozone were used also for partly degrading kerogen to soluble oxidation products. Carbon-balance oxidation tests using alkaline potassium permanganate showed that Colorado oil-shale kerogen differs from many other carbonaceous materials such as coal and kerogens from other areas. Composition of the degradation products indicated that Colorado oil-shale kerogen is predominantly cycloparaffinic and saturated heterocyclic structures with some long-chain paraffinic and aromatic structures present. The ring systems may be connected through short carbon chains or bridges containing oxygen, nitrogen, and sulfur.

Jan 1, 1963

By E. S. Burnett

The temperature entropy (T, S) chart? of thermodynamic properties of nitrogen herewith presented is a complete (1949) revision and a considerable extension of similar charts prepared by the author for use of the helium section of the Bureau of Mines about 25 years previously on the basis of inadequate data then obtaining. During the interval since that early effort, much experimentally determined information on nitrogen properties and behavior has been published, which now permits a more nearly accurate layout and more extensive charting of these relations.

Jan 1, 1950

By C. J. Chindgren

Upgrading of commercial red cake and recovery of vanadium oxide from uranium-vanadium mill solutions were investigated by the Bureau of Mines. Alternative procedures potentially useful for manufacture of high-quality vanadium oxide at the mill site were explored and developed. The simplest and best procedure for converting commercial red cake containing about 10 percent combined sodium and potassium oxides (Na20) (K20) into a 98- to 99-percent vanadium pentoxide (V205 product appeared to be a metathesis in an ammoniacal solution of ammonium sulfate. Molybdenum, as well as the alkali metal oxides, was removed from the red cake by this procedure at a modest expenditure of labor and reagents. When preparing vanadium oxide of higher grade, it was necessary to dissolve the red cake and reprecipitate the vanadium as ammonium metavanadate. Calcination at 450° C, decomposed the metavanadate and yielded oxide of about 99.5 percent V205. By recyrstallizing the metavanadate before decomposition, an oxide product approaching 99.9-percent purity was obtained.

Jan 1, 1962

By C. Q. Cupps, R. F. Zaffarano, J. Fry

Reservoir oil analyses from seven wells in the Greater Clareton area have been included in a study of the original characteristics of oil in the Newcastle sandstone reservoir . These data correlated with areal location of the wells show an increase of saturation pressure in a general north - south or downdip direction . The increase amounts to about 500 psi in more than 17 miles , which corresponds to a depth increase of about 1,600 feet . To facilitate application of the data to engineering analyses , average characteristics are given for arbitrary north and south divisions of the 22 - mile - long producing area . The downdip increase of saturation pressure is taken as evidence of updip diffusion of solution gas from a somewhat higher concentration at the bottom of the reservoir . This effect is opposite to that previously observed in two prominent high- relief reservoirs in the Rocky Mountain area . The increasingly greater saturation pressures southward or downdip in the Greater Clareton area suggest a continuing migration of fluids into the structure .

Jan 1, 1964

By Reinhardt Thiessen

This paper presents only the highlights of previous research on the paleobotany of coal. The accumulated material has become so vast that a comprehensive review of all findings relating to paleobotany would be far too long. The fact that coal is derived from plants is now so well-known that no further comment is required, but knowledge of the mode of transformation of plant substances into coal is not so general. The plant matter goes first through processes of semirottins-, maceration, and elimination of certain material to form peat, which is then further transformed into coal. The first stage has been termed the "biochemical process," because the more important changes take place under the influence of micro-organisms. Near the end of the biochemical action an unconsolidated peat is formed. The second or "dynamochemical process," caused by the addition of superincumbent rock strata such as sandstones and shales and application of additional pressure and possibly heat through mountain-building forces, results in the formation of higher-rank coals ranging from brown coal to anthracite. These stages in trans-formation of plant material to coal have been described in previous reports.4 The main object of this paper is to bring to the notice of paleobotanists the fact that coal contains an enormous amount of material in a remarkably good state of preservation. Although some of the coal-forming matter has lost its identity, much of the original structure is retained. A large proportion of the coal, therefore, particularly of common bright coals, comprises constituents or components that invariably have retained some of the original plant structure, and many of these structures may be assigned to certain plants. The identity of these plants and of the remains forms the subject of this paper.

Jan 1, 1941

By Raghoottma S. Pandurangi, Mohindar S. Seehra, Pedro Bolsait, Bronwyn L. Razzaboni

"Surface IR (infrared) modes of crystalline and fumed (amorphous) silica particles, calcined at temperatures up to 1095°C, have been studied by Fourier transform infrared spectroscopy. The ability of these same particles to lyse cells has been measured by a hemolysis protocol. The untreated crystalline and amorphous materials differ by a factor of 40 in specific surface area, and the intensity per unit mass of the sharp surface silanol band near 3745 cm-1 in the amorphous material is an order of magnitude larger than in the crystalline material. A similar difference is observed in the lysing potential of the two materials. The intensity of the silanol band increases after calcination for both materials, reaching peak values near 500°C, followed by a dramatic drop at higher calcination temperatures, and reaching negligible values for materials calcined near 1100°C. The lysing potential data follow essentially the same pattern for both crystalline and fumed silica. These results are consistent with the hypothesis that the surface silanol groups are involved in cell lysis. Further experiments are suggested to evaluate the relationship between the surface structure of ailica particles and their potential cytotoxicity. IntroductionThe characterization of the surface structure of various allotropic forms of silica is of interest because the cytotoxicity of silica particles of respirable size has been commonly related to the chemical interaction of functional groups on the surface of such particles with the lipoproteins contained in cell membranes (1-3). It has been found that the cytotoxic potential of silica particles varies greatly with their crystalline structure (4,5), particle size (6-8), surface composition (9), and molecular surface configuration (1,10). Studies of the infrared (IR) modes of various forms of silica have been reported by a number of researchers (3 ,11-19). Several books and reviews (20-24) have dealt with the identification of functional groups on silica surfaces and the effect of heat treatment on the surface structure. The nature of the surface is said to be critical in determining the biological activity of silica dusts (3).Fourier transform infrared (FTIR) spectroscopy is a highly sensitive ·technique for identifying IR surface modes of tine particulates, and it was deemed of interest to examine the surface structure and its relation to lysing potential of two widely different types of respirable silica dust. The lysing potential of respirable dust particles has been considered a first-level test for potential cytotoxicity."

Jan 1, 1990

By O. M. Bishop

From October 1943 to March 1944, the Bureau of Mines conducted core drilling at the Victory fluorspar mine, Hardin County, Ill. to test the Fredonia limestone and the included sub-Rosiclare sandstone zone beneath the existing stopes. Twenty-one vertical holes were drilled to an average depth of 60 feet. Ore was penetrated in six holes. Since its discovery in 1927, the Victory mine has produced approximately 5 percent of the total fluorspar mined in the United states after that date. The ore discovered in the early mine development is now exhausted, except that contained in pillars drifting to the northeast has partly developed one substantial ore body, and company drilling has indicated another nearby. The increasing need for fluorite for war use in 1943 suggested the desirability of mining the pillars, provided it could be established that no ore beds existed below the stopes or in areas to which access would be obtained through the present workings. This work describes the work accomplished during the project and presents the data obtained.

Jan 1, 1948

By J. D. Sargent

Selenium might be described as a paradoxical element, being a metal or a nonmetal, a conductor or nonconductor, amorphous or crystalline, colorant or decolorant, and a hydrogenator or dehydrogenator. Selenium was discovered in 1817 by the Swedish chemist, Berzelius, while studying flue dust from the lead chambers of the sulfuric acid works at Gripsholm, Sweden.

Jan 1, 1954

By Margaret R. Egan

This Bureau of Mines report presents results from experimental studies on wood crib fires in an intermediate-scale fire tunnel. Gas concentrations, smoke particle characteristics, heat release rates, and ventilation rates were determined. These measurements form a data base for wood, which can be used with previous analyses for coal and future studies of other mine combustibles, to comprehend the potential hazards of these materials in underground mine fires. A knowledge of the combustion products emitted from these materials will benefit fire detection and control. Results show the changes in burning rate and heat release rate produced by different crib configurations and ventilation rates. Also included are the effects that the burning rate has on smoke characteristics and gas production.

Jan 1, 1986

By Richard J. Bielicki

This Bureau of Mines study estimates the number of major pieces of coal- mining equipment that will be required to produce 950 million tons of marketable coal in 1980 and 1.2 billion tons in 1985. The coal tonnages were projected in the intermediate coal supply scenario of Project Independence Blueprint (PIB). The equipment projections were determined by consideration of historical trends and by evaluation of information from equipment manufacturers and mining companies. The ability of the manufacturers to meet the projected equipment demands was also determined. It was concluded that equipment supply offers no presently discernible constraint to mining 1.2 billion tons of coal in 1985. A shortfall in projected production for the intervening years, however, is probable owing to anticipated shortages of draglines.

Jan 1, 1976

By Robert Torbin

The objectives of the Continuous Shaft Lining (CSL) System are to reduce the costs, safety hazards, and time currently required in lining mine shafts with concrete. The CSL will line machine bored shafts downward from the shaft collar on a continuous basis using an inverted, pressurized slipforming technique. The technique for slip-forming downwards has been demonstrated and refined under this program. The approach taken involved laboratory scale testing of key features of the CSL concept. These feature tests included concrete distribution, concrete sealing, concrete slipforming and development of a reliable concrete mix. Based on these results, a full scale above-ground test facility and CSL were designed and fabricated. The objectives of these tests were to demonstrate the viability of the basic concept; to establish operating limits; and to provide input data and information for the design of a second generation shaft lining system. The results of the program have led to a CSL design and operational philosophy which will need to be tested in an underground environment before industry will accept the technology. However, the next generation CSL promises to meet all the original program technical objectives.

Jan 1, 1983

By V. A. Danielson

The Bureau of Mines examined sources, consumption, and movement of iron and steel scrap in the southeastern States--Alabama, Florida, Georgia, Kentucky, North Carolina, South Carolina, and Tennessee. Officials of the scrap-processing and scrap-consuming industries were interviewed, data was obtained from the published literature, and a canvass was made by the Bureau of scrap consumers. The Southeast generated excess scrap which was shipped to domestic and foreign consumers in about equal proportion. Total 1963 demand in the Southeast was 3,336,000 net tons, of which purchased scrap was 75 percent, foreign exports 13 percent, and domestic exports 12 percent. Alabama, with 47 percent of the purchased scrap consumption in 1963, was the most important scrap-consuming State, and Kentucky, with 34 percent, was the second most important one. Southeast demand was 4.8 per-cent of the total U.S. demand. Projected 1980 consumption is 8,340,000 tons. Scrap prices showed a slight downward trend for the period 1953-63, although gross consumption increased slightly. A significant trend in processing scrap in the Southeast is the preparation of smaller bundles or "briquettes" weighing from 75 to 150 pounds, which are easier for consumers to handle and inspect. Another significant development is the "shredding" of automobile scrap which produces a dense, clean scrap especially desirable for use in electric furnaces.

Jan 1, 1967

By Robert S. Sanford, Harold C. Pierce

"At one time the Alaskan Eskimo lived in many small settlements scattered along the Arctic coast. These settlements extended as far south as Bristol Bay and several miles inland on the large rivers. When the white man established trading posts, schools, hospitals, and missions, these people gradually congregated around them in a few large villages. The natural fuel supply near many of the large villages along the Arctic coast became exhausted as a result of the abnormally large influx of people from small outlying settlements.The population of Barrow, Alaska, according to the 1940 census, is 363 persons, but since that time it has increased considerably, and later estimates place the present population between 400 and 500 persons. With the exception of 25 white persons, the entire population is comprised of Eskimos.The government maintains a school, hospital, radio station, and weather station at Barrow. In addition to the government, installations, there is a church, a privately owned trading post, and cooperative store owned by the Eskimos.For many years the Barrow Eskimos depended on driftwood and petroleum residue from Cape Simpson for their fuel supply. This fuel provided not only warmth for the Eskimo during the long cold winters but also heat for melting ice, the only source of 'water during .the winter. In recent years the sources of petroleum residue and driftwood have not been adequate to meet the demands for fuel During the winter of 1942-43 and again in 1943-44, Barrow experienced an acute shortage of fuel.The fuel problem at Barrow was brought to the attention of Governor Ernest E. Gruening, who was instrumental in getting a Bureau of Mines engineer4/ to investigate reported coal occurrences in the vicinity. Coal deposits along the Meade River and at Peard Bay were examined during the spring and fall of 1943. The Alaska Native Service shipped in mining equipment in September 1943 and commenced stripping an open-pit mine on the Meade River in June 1944. In conjunction with this work, an engineer5/ of the Bureau explored by churn drilling to determine the tonnage of- coal in the vicinity of the mine. In addition to this work, the Bureau of mines examined coal deposits in Peard Bay area and along the Kuk River south of Wainwright."

Nov 1, 1924

By S. M. Shelton, M. M. Fine, T. L. Johnston

"INTRODUCTION The Bynum property is about 15 miles west of Gadsden and 1 mile north of Walnut Grove, Etowah County, Ala. The ore lies in layers and as irregular masses and pockets in the clay residue from decomposed quartzite and limestone formations to the district.The property has been developed by means of numerous shallow shafts sunk to water level - about 25 foot. Operations are confined to small-scale, selective mining of pockets of high-grade ore. The ore is marketed directly, without beneficiation. The property does not yield a large amount of manganese ores. No estimates of reserve ore tonnages are available.A 206-pound sample was furnished for test. It was taken at random from a stock rile estimated to contain 130 tons of ore. The sample con¬sisted of a mixture of manganese oxides, iron oxides, and siliceous fragments in clay. The manganese occurred largely as soft, unconsolidated pyrolusite and wad. Some hard, crystalline pieces of psilomelane were distributed through the soft material. Small amounts of iron oxides were associated with the manganese oxides. Chert, quartzite, and clay comprised the gangue minerals.Dry analysis of the sample was as follows: 36.0 percent manganese, 6.1 percent iron, 2: .0 percent silica, 1.5 percent calcium carbonate, 0.36 percent phosphorus, 3.0 percent alumina, 2.2 percent barium, and 0.31 percent zinc."

May 1, 1942

By Robert H. Merrill

This report contains a summary of the various studies made to determine the structural design of the production mine area of the Oil-Shale mine, Rifle, Colo. Prior to this investigation, it had been determined from a study of the geology, the structure of the deposit, and mining costs that the deposit should be mined by open stoping. The problem remained to determine the maximum safe roof span, the optimum extraction ratio, and the size of the pillars. These factors were determined from a study of the geologic structure of the deposit, the physical properties of the oil shale, and the magnitude and distribution of the stress around proposed underground openings. The latter was determined from both theoretical calculations and model studies. Safe roof spans, pillar sizes, pillar contours, and optimum extraction ratios were calculated from elastic theory and the physical properties of the mine rock. Safe roof spans, pillar sizes; and time effects were determined by Wright and Bucky by testing mine models in a centrifuge. The models were made from rock specimens taken from the proposed mine roof and pillars. The results from both studies agreed.

Jan 1, 1954