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By P. H. Mutschler

The Bureau of Mines studied the Chattanooga Shale to determine the quantity and quality of the uranium resources present and to assess specific environmental effects of mining the shale. Geologic data and chemical analyses, mainly concerning a 12-county area of Tennessee, were compiled from previous published and unpublished reports. Uranium resources in the Gassaway Member of the Chattanooga Shale in this 12-county area were estimated to be between 4.2 and 5.1 million tons, contained in 76 to 91 billion tons of shale. These figures represent inground tonnages and do not allow for mining or processing losses. Depending upon efficiency of mining and processing systems, enough uranium could be available to satisfy a large part of the cumulative domestic and world demand through the year 2000. A model was developed which assesses the total tons or acres of shale to be mined if the Gassaway Member were to satisfy 1 percent of the United States demand for uranium in 1991. This partially demonstrates the environmental impact of mining the shale and is easily factorable to any specified demand.

Jan 1, 1976

By J. Koster

In the western United States occurs deposits of low-grade chromite which, when concentrated, may be reduced to ferrochromiun in electric furnaces that derive energy from dams and hydro plants now in course of construction. Montana ore was chosen for the experiments. A 1-ton sample contained 26 percent Cr203, 17 percent Fed, and 17 percent SiO2, plus other constituents, and the concentrates therefrom assayed 44 -percent Cr203, 23 percent FeO, and 0,79 per cent SiO2, Gravity concentration was found to be the best method. Ferrochromiums are of two grades - high-carbon with 66 to 70 percent chromium and 4-112 to 6 percent carbon and low-carbor with 67 to 72 percent chromium and 0.6 to 2 percent carbon. Both are made in electric furnaces that use anthracite as a reducer and suit-able fluxes. The concentrates mentioned mere smelted under different conditions, and it was concluded that domestic ore could be reduced with anthracite to produce a ferrochromium of S to 10 percent carbon content at yields of 90 percent without re-treating the slag. This carbon may be lowered to required proportion with calcium and silicon, but the former requires a great excess and the latter leaves an alloy high in silicon. INTRODUCTION Chromite occurs in several regions of the United States, but the known deposits of this mineral have not been large enough or high grade enough to permit them to compete under normal conditions with imported ores. There are numerous deposits of chrome ore along the West coast. These are generally conceded to be relatively small, although some were worked during the World War. There are some indications of a revival of interest in California chromites. Montana contains large chromite deposits in Stillwater and Sweetgrass Counties. The utilization of chromite for ferrochromium and. the manufacture of stainless steels is distinctly an electrometallurgical problem; consequently, a study of methods for treatment of chromite might pave the way for the establishment of new electrometallurgical industries in the Western States. This thought is supported by the cheap power that is soon to become available from the western dams, Farther, submarginal domestic chrome deposits might thus be turned into profitable producers.

Jan 1, 1936

By E. H. Burroughs

HISTORICAL REFERENCES OCCURRENCE-GEOLOGY AND ORIGIN. 4. ARNOLD, RALPH. Conservation of the oil and gas resources of the Americas, Econ. Geol., vol. 11, Apr.-May, 1916, pp. 203-222; June, 1916, pp. 299-326; Proc. 2nd Pan American Sci. Cong., 1915-1916, vol. 3, Conservation of natural resources, pp. 207-237. Shows occurrence of oll, and status and possibilities of oil Industry in each country. Discusses briefly ways in which oll reserves may be conserved. 5. RUTIS, A. A. Petroleum known since remote times. Oil and Gas Jour., vol. 15, Nov. 2, 1916, pp. 33, 37. Gives historical reférences to the use of petroleum from Bible times to its discovery In America. See also Nos. 3, 257, 202, 337, 1843.

Jan 1, 1919

By J. Koster

In the western United States occurs deposits of low-grade chromite which, when concentrated, may be reduced to ferrochromiun in electric furnaces that derive energy from dams and hydro plants now in course of construction. Montana ore was chosen for the experiments. A 1-ton sample contained 26 percent Cr203, 17 percent Fed, and 17 percent SiO2, plus other constituents, and the concentrates therefrom assayed 44 -percent Cr203, 23 percent FeO, and 0.79 per cent SiO2, Gravity concentration was found to be the best method. Ferrochromiums are of two grades - high-carbon with 66 to 70 percent chromium and 4-112 to 6 percent carbon and low-carbor with 67 to 72 percent chromium and 0.6 to 2 percent carbon. Both are made in electric furnaces that use anthracite as a reducer and suit-able fluxes. The concentrates mentioned mere smelted under different conditions, and it was concluded that domestic ore could be reduced with anthracite to produce a ferrochromium of S to 10 percent carbon content at yields of 90 percent without retreating the slag. This carbon may be lowered to required proportion with calcium and silicon, but the former requires a great excess and the latter leaves an alloy high in silicon. INTRODUCTION Chromite occurs in several regions of the United States, but the known deposits of this mineral have not been large enough or high grade enough to permit them to compete under normal conditions with imported ores. There are numerous deposits of chrome ore along the West coast. These are generally conceded to be relatively small, although some -were worked during the World War. There are some indications of a revival of interest in California chromites. Montana contains large chromite deposits in Stillwater and Sweetgrass Counties. The utilization of chromite for ferrochromium and. the manufacture of stainless steels is distinctly an electrometallurgical problem; consequently, a study of methods for treatment of chromite might pave the way for the establishment of new electrometallurgical industries in the Western States. This thought is supported by the cheap power that is soon to become available from the western dams. Farther, submarginal domestic chrome deposits might thus be turned into profitable producers.

Jan 1, 1936

By Michael Schmitz, Eugene Ahrenholtz, William A. Heitbrink, Jeanne A. Zimmer, Andrew B. Cecala, Ernest S. Moyer, Earle H. Andrews, Chris C. Coppock, John A. Organiscak

Many different types of surface mining equipment use enclosed cabs to protect equipment operators from health and safety hazards. The overburden removal and mining process can be extremely dusty and can cause excessive dust exposure. To study this issue, a cooperative research effort was established between the National Institute for Occupational Safety and Health, U.S. Silica Co., Clean Air Filter Co., and Red Dot Corp. in an effort to lower respirable dust levels in an enclosed cab on an older surface drill at a silica sand operation. Throughout this research effort, a number of modifications were incorporated into the drill's filtration and pressurization system, as well as in other areas, to improve its design and performance. An average cab efficiency of 93.4% was determined with gravimetric sampling instruments when comparing the outside with the inside cab dust levels on the final design. Although this study considered just one operation, the goal was to identify cost-effective improvements that could be implemented on all types of enclosed cabs to lower respirable dust concentrations. Two critical components for an effective enclosed cab system are having a properly designed, installed, and maintained filtration and pressurization system, along with a method for maintaining structural cab integrity, which allows the cab to be positively pressurized. Another important component is maintaining cab cleanliness. Although this research was originally directed toward the mining industry, it is also applicable to agricultural or construction equipment.

By G. F. Kuncir

The analysis described herein evaluates the Bureau of Mines Program for Advancing Mining Technology - Oil Shale in terms of the economic benefits which may be derived for the Nation as a result of its successful research and development efforts. On the basis of postulated oil shale production scenarios, benefit-cost ratio indicators are computed for the program elements as they apply to surface, underground, and modified in situ oil shale mining systems. Eight value indicators are used to measure the Program's beneficial impact on the future oil shale industry in relation to planned research and development costs. These are: capital cost savings, operating cost savings, labor savings environmental quality maintenance cost reduction, reduction in production costs, byproduct production benefits, total production benefits, and additions to recoverable reserves. Program costs are aggregated from 1974 through 1987 and major benefits are accrued from 1982 through 2040. Both cost and benefit streams are discounted to mid-1975 present value.

Jan 1, 1977

By Wilford S. Wright, Harold E. Heide, Robert S. Sanford

"INTRODUCTION The United States production of tin has always been negligible, and domestic requirements have been met almost entirely by imports. The advent of war in Europe in 1939 brought a threat to our foreign source of supply, and steps were taken by Congress to forestall shortages of tin and other metals. By authority of the Strategic Minerals Act, passed by Congress in 1939, the Bureau of Mines and Geological Survey conducted investigations of domestic tin deposits.An examination of Alaska deposits was undertaken in 1940 and 1941 by J. B. Mertie, Jr., and Robert R. Coats of the Geological Survey.H. B. Heide conducted a preliminary examination of lode and placer-tin deposits at Cape Mountain in 1942, which was followed in 1943 and 1944 by a program of exploration by churn drilling in the placer area and trenching and sampling the lode deposits.Placer tin, found at the head of Goodwin Gulch, Cape Creek, First Chance Creek, and Boulder Creek, indicates that the mineral was derived from the vicinity of lode cassiterite occurrences on Cape Mountain. Placer tin led to the discovery of at least one, cassiterite vein by the Geological Survey and the Bureau of Mines."

Dec 1, 1946

By Jr. Koch

As a part of a larger study of the distribution of metals within ore deposits, the geometry of distribution of gold, silver, lead, copper, and zinc in five veins of the Fresnillo mine, Zacatecas, Mexico, was established. The purpose was to obtain basic data necessary for evaluation of geological theories about processes of vein formation and useful for practical mining applications in ore estimation and prediction of ore beyond present workings. The Bureau of Mines investigation comprised statistical analysis of 64,000 assay values from some 16,000 mine samples. The samples were taken at 2-meter intervals in drifts exposing the veins through a vertical range of some 750 meters. Within individual veins, the metals are distributed in dome¬like patterns with highest metal contents tending Lo occur in oreshoots at the centers of the developed parts of the veins. However, in the block of ground containing all five veins, base metals define mathematical domes with highest contents near the center; precious metals define mathematical basins or troughs with low contents near the center. The ratio of silver assay values to lead assay values corresponds to two geographically distinct types of mineralization: one in which silver is closely related to lead, and another in which silver is independent of lead. Other metal ratios also vary regularly from one place to another. The statistical methods employed in this study would be useful for other geologists or engineers who need to analyze large amounts of assay or similar numerical data.

Jan 1, 1967

By B. M. O'Harra

The residues resulting from the retort distillation of zinc ores have from 40 to 75 per cent of the weight of the original ore and contain from 5 to 15 per cent zinc . A rough estimate indicates that approximately 450,000 tons of residues are produced annually in the United States , containing about 36,000 tons of zinc . Besides the current production of residues there are at many smelter sites large accumulations from past operations which are available for treatment if this can be done profitably . In addition to their zinc content the residues contain much unconsumed coal , which has been carbonized during the distillation process , and those from most western ores also contain lead and silver . In this paper is summarized the information obtained in a survey , recently made by the Bureau of Mines , in cooperation with the Missouri School of Mines and Metallurgy , of processes which are in use or which have been suggested for the treatment of retort residues . The complete report of the survey is to be published as a Technical Paper of the Bureau of Mines .

Apr 1, 1923

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975

By Nan C. Jensen

Modern high-temperature metallurgical processes have created a demand for raw material for furnace parts and lining that not only will with-stand high temperatures is but will not react with the substance being melted in the furnace. Spark-plug insulators, laboratory ware, tanks for the glassmaking making industry, and saggers and kiln furniture for the chinaware and pottery trades also must be made of materials hat have high melting points. Among the minerals that can be employed for such refractory uses ore those commonly known as the "sillimanite group' -kyanite, andaluste, sillimanite, and dumortierite - and the allied minerals topaz and pinite. Consideration of the occurrence, properties, qualities, uses, and sources of supply of these commodities and the markets for them constitute the subject of this paper. General Features of Kyanite and Related Minerals Kyanite, andalusite, and sillimanite ire composed of three elements - aluminum, silicon, and oxygen ? and are called aluminum silicates. The have

Jan 1, 1943

By R. S. Dean

In addition to the normal work and that pertaining to strategic minerals, the Metallurgical Division has been made responsible for carrying on major investigations in the development of processes' for the treatment of low-grade domestic manganese ores that heretofore have failed to yield products suitable for the preparation of ferromanganese, an alloy essential to every ton of steel produced. These investigations are particularly important at this time because of their part in tucking this country self-sufficient with regard to manganese when the stock-piled ore becomes e exhausted and as foreign shipments of ferro-grade ore are cut off. The results indicate that there is a good probability of accomplishing this objective, while at the same time conservation may be promoted through the use of normally useless material from the large, low-grade ore deposits.

Jan 1, 1941

By Avery H. Reed

[The Bureau of rides is making a general study of the occurrence of the Clinton red iron ores of Alabama. In the course of this study, it developed that the iron-ore seams of the Woodstock and Bucksville areas were virtually unexplored., and the nature and extent of the ore deposits were undetermined. As a part of the work of the project, the Bureau investigated the occurrence of red iron ore in the .areas. Eighty-four channel samples, representing 317.6 linear feet, were taken from l2 locations along the outcrop of the red iron-ore seams, Ten diamond-drill holes, amounting to 3915.5 linear feet, were drilled. In these areas, commercial- and marginal-grade ores of minable thickness have been shown. It is estimated that 4,500,000 tons of indicated ore and 6,700,000 tens of inferred commercial-grade ore averaging 5.1 feet thick, 47.6 percent Fe, 26.1 percent insoluble, 0.1 percent CaO, and 0.04 percent P; 7,200,000 tins of inferred marginal grade ore averaging 6.1 feet thick, 36.2 percent Fe, .35.0 percent insoluble, 3.9 percent CaO, and 0.14 percent P; and 18,500,000 tons of ferruginous sandstone averaging 12.2 feet thick, 19.2 percent re, 50.1 percent insoluble, 9.6 percent CaO, and 0.14 percent P are present in the areas.. All tonnages are estimated as gross tons of recoverable ore in place, based' on 65-percent mining recovery. In accordance with established policy of the Bureau of Mines of publishing factual data as soon as possible after completion of field work, this description of the Woodstock and Bucksville areas is presented. As soon as work is completed in other areas additional reports will be prepared.]

Jan 1, 1953

By Travis Q. Lyday

During 1983, Ecuador's gross domestic product (GDP) decreased by a reported 3.3% in real terms, the second consecutive decline in the economy after more than a decade of growth generated mainly by petroleum export revenues. The slowdown was due, in part, to the effects of the world recession, lower foreign demand for oil, depressed world oil prices, and reduced demand and prices for Ecuador's traditional agricultural exports. Inflation accelerated to an estimated 55% annual rate. The sucre was devalued in March, for the second time in less than a 12-month period, by 27% after remaining unchanged during the previous decade. In addition, continuous adjustments were made every weekday, effectively devaluing the sucre another 30% by yearend. Ecuador's production of crude petroleum increased almost 12% in 1983 compared with that of 1982. Average daily production was 237,100 barrels per day (bbl/d), up from 211,300 bbl/d in 1982.

Jan 1, 1985

By John J. Ginty

The objective of the work reported herein was to evaluate state-of-the-art repeaters used in wireless communications to determine their suitability for use in extending the range of portable and mobile communications in underground mine applications. The scope of the work included wireless repeaters in the frequency range from LF (500 kilohertz) up to the one giga-hertz range. These repeaters included not only single-channel repeaters, that is F1/F1 repeaters for short range simplex party line communications, but in addition, F1/F2 type repeaters currently commercially available in the HF, VHF and UHF bands.

Jan 1, 1975

By N. H. Snyder

THE Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heating value of the coal, expressed in British thermal units, and the com-position as shown by proximate analyses. To these, when required, are added the fusing temperature of ash, Hardgrove grindability index, and the free-swelling index. Under most of these specification contracts the bidders guarantee the quality of coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions 4 issued by the Bureau; the samples are analyzed in the Bureau's laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made. Analyses of delivered coal and "tipple" samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) are valuable data for use in evaluating future bids. Moreover, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1953

By E. M. Frost

"A new apparatus has been devised for quickly and precisely analyzing natural gas for its helium content. The following outstanding advantages make it far superior to any equipment now available for the purpose.3/4/5/6/1. It enables more rapid determinations to be made.2. It has far greater sensitivity than previous apparatus. 3. It is portable.Fifty or more samples may be analyzed in an 8-hour day with the new apparatus and procedure. A maximum of about 10 samples per day could be analyzed with previous apparatus. In the apparatus described, the volume of pure helium obtained from a sample is determined by measuring the pressures created by that pure helium when it is expanded into a constant calibrated volume. In older methods the pure helium separated from a sample is pumped into a burette and measured at atmospheric pressure. The new apparatus and Procedure used with it reduce the average time for an analysis from about 40 minutes to less than 10 minutes,Samples containing a few thousandths of a percent helium may be analyzed as readily as samples containing 1 percent or more, This was not possible with former apparatus. Duplicate samples containing a few thousandths of a percent helium have been analyzed, results checking to one ten-thousandth of a percent. Attempts to measure a corresponding volume of helium in a burette at atmospheric pressure become futile. The ability to determine very small quantities of helium has become of great importance recently in gas- and oil-field engineering studies such Os the utilization of helium as a tracer gas in following the movement of gases through underground structures.A complete apparatus was recently carried more than a thousand miles in a passenger automobile. It arrived without breakage, was .set up and ready to make an analysis in a few hours. .Former apparatus was not portable. The portability of the present apparatus permits taking the apparatus to the field for more efficient prosecution of field engineering problems. The only services required in the field are electricity, tap water, and a source of liquid air or liquid nitrogen.The principle involved is based upon the fact that large volumes of all the constituents usually found in natural gas, except helium, are adsorbed quantitatively on cocoanut charcoal that has been cooled to the temperatures of liquid air. A volume of sample is measured and transferred to a tube of cocoanut charcoal maintained at the temperature of liquid air. After adsorption of all the constituents other than helium, the charcoal tube is connected to a sensitive pressure-measuring device, and the Percentage helium originally in the sample is calculated from two pressure readings and the volume of the original sample."

Jun 1, 1946

By C. E. McElroy

"INTRODUCTION The ventilation of working places in mines by jets of air discharged from fan-pipe lines is an important phase of mine ventilation, whether the primary purpose is to dilute gas or dust concentrations or to provide air-motion cooling effect. Jets of similar nature are very prominent factors in the ventilation of enclosed spaces, such as buildings and ships. The effectiveness of such jets depends on the distribution of the air in the jet streams, a subject on which the little definite information previously available applied to jet discharge into large, open spaces under conditions quite different from those ordinarily associated with fan-pipe discharge in mines.The results of an initial series of experiments on the discharge of air from fan-pipe lines in mine openings have been described. 3/ This report presents the results of a second series of experiments and compares the results of both series with theory and experiment on jet discharge into large, open spaces. The results of this second series confirm and supplement those of the initial series, in which a 10-inch pipe discharged into an 8- by 8-foot develop¬ment end through seven short discharge pieces of different designs. In the present series the same 10-inch line was used, but the discharge was through 10- to 30-foot lengths of 5-inch, 10-inch, and 20-inch-diameter pipes and through a 20-foot length of 29- by 3-inch pipe. Tests were made with the air discharged into a closed drift or development end, as in the previous series (in which case the discharged air returned past the end of the pipe) and into an open drift (in which case the discharged air did not return past the end of the pipe but continued out along the drift). Test conditions corresponded to the discharge of a jet into a channel closed at one end; in one case, the discharge was directed toward the closed end and in the other toward the open end. The former typifies fan-pipe ventilation of development ends and the latter an abrupt increase in the sectional area of an airway. In both the flow had to pass from jet to open air against some resistance.The tests were made in the Mount Weather Testing Adit of the Bureau at Bluemont, Va., on the pipe line installed for ventilating the adit, and extended from late September to mid-November 1940. Preparations were made for directly comparable series of experiments on the injector effect of fan-pipe discharge in an open drift and on free expansion in large, open spaces, but these test programs were .first postponed in favor of other work and finally abandoned until the war is over."

Nov 1, 1943

THIS bulletin presents all analytical and lest methods regularly used by Bureau of Mines laboratories for characterizing coal and coke. To provide better service to coal producers and consumers, the scope of this bulletin has been expanded to include important test methods used to evaluate coal properties for commercial processing. The methods described will prove valuable to all persons interested in analyzing and testing coal and coke.

Jan 1, 1967

By Gerald T. Homce

A system capable of monitoring mine electrical power systems and detecting impending component failure could significantly improve power system safety and reduce unscheduled equipment downtime. Such monitoring would require a method of evaluating electrical parameters, calculated from terminal values, for indications of component deterioration. The U.S. Bureau of Mines has targeted electrical failure of squirrel cage induction motors and examined the use of mathematical models to aid in this evaluation. The initial stage of this work is complete, and has produced polynomial networks called adaptive learning networks (ALN's) that can detect and quantify winding insulation leakage simulated on laboratory motors. In this modeling process, empirical data from laboratory motors were used to select the electrical parameters most significant for assessing motor conditions, and mathematical expressions relating these parameters to simulated deterioration were formed. ALN's developed thus far can process readily measured motor terminal information and quantify power and current levels of laboratory-simulated leakage to within 1% and 3% of full load values, respectively, for motors in the 10- to 150-hp size range. The next stage of this research is validation of these ALN's for actual motor failures; this stage is currently underway, using accelerated life testing of laboratory motors.

Jan 1, 1993