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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 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 P. L. Swanson, F. M. Boler

The U.S. Bureau of Mimes conducts research at the Galena Mine, Wallace, ID, with the aim of mitigating the effects of rock bursting. Destress blasting is commonly used as a stress control technique at the mine. A digital seismic array and an array of borehole pressure cells (BPC's) had been installed near the site of a stope undergoing mining and periodic destressing. The instrumentation was being monitored at the time of a destress blast of the 46-99 stope. No significant seismic events occurred coincident with the destress. However, the destress was followed by a 21/2-week period of increased seismic activity, including two damaging events on February 7, 1990, at 034500 (hour, minute, and second) and 122020 Pacific standard time. BPC measurements indicated coseismic ground pressure changes on the order of 200 to 300 kPa associated with the damaging events. Fault plane solutions and dislocation models established that stress changes induced by the event at 034500 may have been significant in promoting the occurrence of the event at 122020. Theoretical investigations suggest that applying knowledge of the existing stress field, an understanding of rock burst mechanics, and fracture mechanics principles can improve destress effectiveness.

Jan 1, 1993

By H. H. Storch

"INTRODUCTION The first paper of this series contained data concerning the behavior of polyhalite (K2S04.MgS04.2CaS04.2H20) upon calcination and subsequent leaching with water at 100° C. It was found that upon heating polyhalite to temperatures between 298 and 500° C. the water of crystallization is driven off, leaving, an amorphous mixture of K2S04, MgS04, and CaS04. Two transition points were located; one at 298° C. which coincides with the vigorous evolution of steam; and one at 551° C. which results in the formation of a hard mass of crystals. The latter probably consist of a solid solution If the compounds langbeinite (K2504, 2MgS04), potassium dicalcium sulphate (K2304. 2CaS04), and anhydrite (CaS04). The heat of decomposition of polyhalite at 298° C. was measured and found to be 66,000 ± 5,000 calories per mol. The optimum temperature of calcination with regard to subsequent extrac¬tion with two parts of water (at "" 0° C.) is 430 to 450° C. for 65 to 100 mesh material, if one half hour at the calcination temperature is allowed. The maximum concentration of K2S04 obtainable in the extraction of calcined polyhalite is 11.4 grams per 100 grams of water. This concentration of K2304 is considerably above the equilibrium value (3.6 g. per 100 L. of H20 at 83° C.) with respect to the solid phases polyhalite, potassium calcium pentasulphate, ¬and anhydrite. The figure 11.4 K. of K2804 per 100 g. of H20 is also somewhat than the equilibrium value (9,65 g. per 100 g, H20) with respect to the solid phases potassium calcium pentasulphate and syngenite."

Oct 1, 1930

By Kenneth M. Maas

The Bureau of Mines inventoried all lands in Alaska to determine the availability of land for oil, gas, and coal leasing. Acreage for onshore oil, gas, and coal basins was digitized as was land ownership data. Regulatory policy concerning oil, gas, and coal leasing for various government agencies and private concerns was determined. Oil and gas basins underlie 79.4 million acres of Alaska's 378 million acre landbase. Federal agencies manage 44 million of these acres. The Bureau of Land Management is the lead agency for most oil and gas leasing on Federal lands. Lands have to be specifically opened for oil and gas leasing to be available. The state of Alaska manages 21.1 million acres underlain by these basins. More than 80 percent of this acreage is available for resource development. Native corporations manage the remaining 14.3 million acres of favorable oil and gas land. Coal basins underlie nearly 51 million acres of Alaska. Of this land, 26.4 million acres are under Federal jurisdiction. The state manages 17.3 million acres of land underlain by coal basins. Nearly 7.3 million acres of favorable coal lands are managed by Native corporations.

Jan 1, 1991

An active list of permissible explosives was published in July, 1931, as part of United States Bureau of Mines Report of Investigations 313, under the title of "Active List of Permissible Explosives and Blasting Devices Approved Prior to June 30, 1931." Changes in that list were authorized in August, September, October, November, and December, 1931, and. January and March, 1932, as published in Reports of Investigations 3l40, 3147, 3l50, 3155, 3158, 3161, and 3163, respectively. By these changes the following explosives were added to the active permissible list: [Austin Red Diamond No. 1, L. F. Gel-Coalite W. L. F. Austin Red-Diamond No. 5, L., F. Gen-Gel No. 2. Black Diamond Nu-Gel No. 1 Genite C-1 Burton 1, L. F. Liberty No. 4 Burton 2, L. F. Liberty No. 5 Burton 10, L. F. Peerless D Burton 12, L. F. Permigel 1, L. F. Burton F, L. F.]

Jan 1, 1932

By R. L. Kidd, T. H. Miller

"INTRODUCTION This paper is the seventh of a series of yearly reviews started in 1921 and pre¬sents information gathered in a cooperative investigation undertaken by the United States Bureau of Mines and the University of Utah. It is the purpose of this report to make available flotation—reagent consumption data and other milling information in such a manner as to be of value to the milling industry and to the manufacturer of flotation reagents.These data have been compiled from a survey of about 300 concentration plants in the United States. Much additional information has been obtained from the various offices of the United States Bureau of Mines. Many of the plants covered in the survey made complete reports of their operations, but others were apparently unable to supply this information in sufficient detail to meet the requirements of this report. As a result, some sections of the report are more complete than others. In general, however, the mill reports were much more complete than in previous years, and for the first time it has been possible to calculate average mill recoveries in the treatment of certain classes of ores. As in the past, every effort has been made to conceal individual plant operations.ACKNOWLEDGMENTSIt is realized that the publication of this information is possible only through the assistance of the mill operators, and the authors wish to express their appreciation of this cooperation. Thanks are also due the various field offices of the United States Bureau of Mines, division of mineral statistics, for assistance in collecting this information."

Aug 1, 1931

A system to continuously measure the concentration of radon in mine ventilating air has been developed and tested in a uranium mine. In use, the air/radon mixture to be monitored is pumped through filters into a scintillation cell where nuclear decay of the radon produces flashes of light. These are electronically counted, giving a quantitative measure of the radon present. Air is continuously drawn from the mine atmosphere into the radon sensor box. This air sample passes through two filters into the detector cell as shown in the schematic diagram. A portion of the radon in the detector cell will experience nuclear decay, producing polomium 218 and an alpha particle. The alpha particles from the fraction that decays strike a zinc-sulfide coating on the inside wall of the cell and produce flashes of light. These enter a photo-multiplier tube which records each flash as an electrical pulse. An amplifier increases the voltage of each pulse, allowing electronic screening to remove noise and other undesirable pulses. The remaining pulses are counted by a conventional data acquisition system.

Jan 1, 1978

By T. A. Klinefelter

KYANITE and the related minerals sillimanite, andalusite, dumortierite, and topaz are natural aluminum silicates that can be used in production of mullite (3A1203?2Si02), a superduty refractory material. Kyanite and sillimanite are the dominant ones because of their greater abundance. The only other kyanite-group mineral presently used for mullite production is andalusite. Mullite is not an absolutely essential material as other refractories can be used in the same heat range. However, it is a highly satisfactory one. It is the only compound of silica and alumina that is stable at high temperatures. It has low thermal expansion and is very resistant to corrosive melts and to thermal shock. For these reasons mullite refractories have a much longer life than standard fire-clay refractories under the same conditions. Worldwide, excluding U.S.S.R., the refractories industry consumes about 150-000 short tons annually of kyanite group minerals and synthetic mullite.

Jan 1, 1961

By J. R. Alldredge

This Bureau of Mines report presents a computer code that has been developed for describing and testing the statistical distribution of general continuous data sets. The statistical distributions used include the normal, lognormal, exponential, chi square, gamma, and uniform. Histograms for observed and expected values are plotted for each distribution. An example using geologic data obtained from a study of the geometric properties of natural fractures in oil shale rock illustrates the use of the computer program, GDIST.

Jan 1, 1977

By John Wilson

This report describes the performance of Phase I of a project to design, analyze, and demonstrate a multilift longwall mining method applicable to mining coal seams twelve (12) feet or more in thickness. A non-simultaneous multilift operation is the most viable thick seam mining technique for introduction to the United States coal industry. In the case of the proposed site at Emery, Utah it will result in an increase in coal extraction from 30% with present methods to at least 50% and possibly more. The major technological advance involved in this project is mining a lower lift under a previously mined upper lift. To accomplish this, entries must be developed and maintained beneath the upper lift gob. This will necessitate the use of steel supports at frequent intervals throughout the lower lift' entry system. This has not been done in the U.S. to date. An economic analysis of the project indicates that, while this method will result in a higher than average cost per ton for coal mined, the coal would be competitive with current-operation in the area.

Jan 1, 1976

By Henry Kreisinger

Some of the investigations conducted by the Bureau of Mines have for their object the collecting and disseminating of information regarding methods by which the fuels of the country may be most efficiently used. As the analysis of flue gases tends to develop better methods of firing, which in turn reduces waste of fuel, the Bureau of Mines in this bulletin presents for the benefit of those in charge of boiler plants and all other persons interested detailed information on methods of sampling and analyzing flue gases, and on the utilization of the analyses in promoting boiler-room economy. This bulletin is intended to be a companion to Technical Paper 80,a and is written in plain and nontechnical language, as far as possible, so that it may be readily understood by persons who have not had the advantage of a technical education. Whenever possible, illustrations of apparatus and methods of handling have been used rather than elaborate descriptions.

Jan 1, 1915

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 M. A. Trevits, T. A. Gray, L. M. Crayne, P. Glogowski

Mine seals can he remotely constructed in underground coal mines through vertical boreholes when direct access to a fire is impossible or considered to he too dangerous. This method has great merit because the boreholes can be drilled to specific mine areas, and the seals can be positioned close to a fire zone. The technology however can be largely ineffective if the constructed seals do not provide of effective barriers to airflow or if they cannot he used to impound water and other inert materials. Unfortunately, no viable alternatives exists to sealing the entire mine to the ground surface. Full-scale remote mine seal construction research is being conducted at the National Institute for Occupational Safety and Health (NIOSH) Lake Lynn Laboratory (LLL). Under this effort. Howard Concrete Pumping Company and GAI Consultants Inc. have joined forces to evaluate a potentially significant improvement to the current state of the art. This paper covers the development o f novel technology or rewrote mine seal construction, the evaluation of rite materials used, the construction practice and the Fellow-up testing.

The Bureau of Mines, through its Minerals Availability Program (MAP), investigates the mineral supply potential of the United States and market economy countries (MEC's) for a number of minerals considered essential to the U.S. industrial base. Major activities include identification of important mines and mineral deposits, estimation of their mineral resources and production costs, and availability and sensitivity analyses. Products include data print-outs of geological and engineering information, discounted- cash-flow rate of return (DCFROR) analyses of individual mining operations, commodity availability appraisals, and analytic services to Government agencies. These products are used in assessing the mineral supply position of the United States: in setting priorities for research aimed at reducing production costs and minimizing adverse environ- mental impacts and regulatory compliance costs of mining and mineral processing operations; and in formulating and evaluating Government policies that affect minerals. Bureau MAP data and analyses have been provided to the executive and legislative branches to aid in consideration of trade, tax, and stockpile policy issues. A study of the economic potential of selected seabed mineral resources supports the regulatory responsibilities of the Department of the Interior in the U.S. Exclusive Economic Zone. Analytic studies of mineral project viability, industry competitiveness, and import dependencies were also undertaken for, or in cooperation with, U.S. and foreign government agencies, industry and trade organizations, and international lending institutions.

Jan 1, 1987

By Horst Peter Wölfel

The goal of biodynamic models is to simulate the vibration behaviour of the human body. In combination with experimental studies biodynamical models can be a powerful tool for the analysis of the effects of vibration exposure on health [1] and comfort. This paper gives an overview of the state of the art of biodynamic whole-body vibration models of humans, addressing both numerical models and hardware dummies. Method Two approaches are distinguished, the phenomenological and the anatomical, as illustrated in Figure 1. [ ] Phenomenological models aim to reproduce the vibration behaviour of humans with respect to particular physical quantities, chiefly the driving-point impedance at the interface to the seat, and partly with respect to other transfer functions. Discrete systems of masses, springs, and dampers with several degrees of freedom whose topology and parameters are determined by structure- and parameter identification methods are used in the sense that the functions derived from measurements are reproduced as well as possible. This paper provides an evaluation of this methodology and defines its range of application as well as its limits.

Jan 6, 2006

By L. V. Clark, Arthur La Motte

"INTRODUCTION The U. S. Bureau of Mines in 1930 and 1931 made a study of the properties and characteristics of liquid-oxygen explosives (L.O.X.) at the request of one of the largest users, in order to determine and eliminate the hazards attending its use.This report deals with the examination of absorbents for L.O.X. to (1) determine their most desirable and most undesirable characteristics, (2) to find ways and means of desensitizing absorbents to mechanical shock, and (3) to determine the effect that such desensitization of absorbents has on the explosive Characteristics of L.O.X.ABSORBENT MATERIALS The absorbent used in driving the Simplon Tunnel, the earliest project in which L.O.X. was used, was composed of crude petroleum, soot, and kieselguhr. During the World War, powdered cork, soot, sawdust, powdered straw, or other similar powdered materials were mentioned in the German military instructions for use of ""liquid air"" explosives. At that time the common types of absorbent, materials were compounded ones containing the above ingredients as well as kieselguhr, paraffin, gas oils, charcoal, bituminous coal, etc.Kuryla and Clevenger4 investigated absorbents of the above type and made the following statement concerning them:"

Apr 1, 1932

By C. D. Messelt

The Bureau of Mines investigated the application of a diffusion model to sintering rate data developed for lithium titanium ferrite. The data were obtained by sintering pressed pellets under identical conditions for various times up to 11 hours. Stereological measurements were made on polished sections, and sintering rates were calculated. A model for intermediate stage sintering was fitted to the stereological data. This procedure produced a method by which these type data could be used to study the relative importance of volume and grain-boundary diffusion under a variety of sintering conditions.

Jan 1, 1979

By F. P. Haver

The Federal Bureau of Mines developed a 10,000-ampere cell to determine the economic feasibility of producing high-purity electrolytic titanium from mill scrap or offgrade sponge. Operating variables were investigated, matetial handling procedures were established, and the cost of electrorefining titanium was determined. The prototype cell produced premium-grade metal (<100 Brinell hardness number (B.h.n.)) from very impure Kroll sponge at a processing cost of less than $0.60 per pound. Refined metal was deposited at the cathode in the form of coarse (85 percent plus 34-mesh), hexagonal crystals of a titanium when the cell was operated an 850° C. A cathode current density of 1,000 amperes per square foot and a molten sodium chloride electrolyte containing approximately 5 percent by weight of soluble titanium were used. In continuous operation, at the optimum number of ampere-hours, (40,000), the current efficiency averaged slightly less than 60 percent. It was possible to supply large enough amounts of electric current for electrolysis to maintain the temperature of the bath, thus reducing overall power consumption to less than 5 kilowatt-hours per pound of metal refined.

Jan 1, 1961

By Gerald V. Gibbs

Quadratic functions, Q(hkl), are given to six places in increments of 0.01° for 2? from 0° to 90° for CuKa and from 25° to 180° for CuKa1. The wavelengths used for Cu in the computation are those agreed upon by the Editorial Commission of the International Tables for X-ray Crystallography (1950): CuKal 1.54051 A.; CuKa2 1.54433 A. INTRODUCTION At the Federal Bureau of Mines laboratory, Norris, Tenn., X-ray diffraction crystallography using tubes with copper targets revealed a need for a handy reference for the quadratic functions of copper radiation. The tables presented here were prepared to satisfy that need. The quadratic form Q(hkl) may be expressed in terms of the Bragg diffraction angle 2? and of the wavelength ? as

Jan 1, 1961