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By Robert C. Hickman

"INTRODUCTION The Big Four fault and the Sandy Creek fault, with several cross faults, traverse the Stalion-Curnel fluorspar prospect in a northeasterly direction. The Big Four mine, about three-quarters of a mile northeast of the prospect, is the only active mine in the immediate area.A resistivity survey was made of a portion of the prospect by the Division of Geophysical Exploration, Bureau of Mines, in May and June 1946. As a result of this survey, five holes were drilled by the Bureau of Mines during the period from October 8 to December 16, 1946. Two Longyear No. 12 Junior Straitline diamond drills were used for the work.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Division, Lowell B. Moon, chief, conducts preliminary examinations, does the actual investigative work, and prepares the final report. The Metallurgical Division, Oliver C. Ralston, chief, analyzes samples and makes beneficiation tests.The project was under the supervision of Mitchell H. Kline, chief, Raleigh Branch, Mining Division."

Mar 1, 1948

By D. Debasis, Christopher Mark, Gregory M. Molinda

The stability of any underground opening is, in large part, a function of the strength of the rock mass which surrounds it. The Coal Mine Roof Rating (CMRR) has been developed to quantify the defects in the rock mass and compile a strength value which can be used for engineering design. The CMRR has been applied to a number of ground stability problems, including chain pillar design, roof bolt selection, hazard assessment, intersection design, and numerical modeling. The CMRR procedure and some of these applications are described in this paper. The CMRR will soon be available in a Visual Basic computer program, allowing easy integration into exploration programs and standard roof fall assessments.

By L. E. Schultze

[The Bureau of Mines conducted bench-scale studies to develop techniques for stripping tetravalent cerium from tri-n-butyl phosphate solutions. Experiments were conducted in a constant-temperature bath using beakers and mechanical stirring. Ninety-five pct of the cerium was stripped from a 50-pct tri-n-butyl phosphate 50-pct kerosene solution containing 0.18 M cerium in 15 minutes at 50° C using 0.11 M aqueous formaldehyde.]

Jan 1, 1974

By S. D. Maksimovic

The use of vertical surface degasification boreholes with bleeder systems and the use of a timbered bleeder system to degasify gob areas were studied by the Bureau of Mines. This report describes three gob degasification studies conducted in the Pittsburgh coalbed. One study was conducted to determine the number of panels degasified with one large borehole. The study showed that the borehole provided degasification for three panels. Another study was conducted during the retreat of a 35-acre panel with a single-entry and a two-entry bleeder system and a large surface borehole. A major portion of methane emitted from the panel was carried away by the bore-hole, leaving the bleeder entries relatively free of methane. The last study was made to determine the effectiveness of a timbered bleeder system. The bleeder entries successfully degasified the gob area when enough entries were available and adequate pressure was available to force the air through roof falls.

Jan 1, 1980

By George S. Rice, C. W. Owings

"Brattice cloth is an important material in coal-mine ventilation practically all coal mines use some brattice cloth, gassy mines a large amount. It is employed in three ways:Crosscut brattices.Curtains in haulageways.Line brattices in gassy mines.In each case brattice cloth is used to deflect part or all of a split of the mine ventilating current into or toward the face of a working place. As a general rule, its use in a particular location is temporary.A crosscut brattice should be employed only until a permanent stopping has been erected. Such a brattice is subject to little wear when in actual service, the chief damage occurring when it is taken down and put up again.When used for curtains on haulageways or haulage crosscuts to deflect the air current up into rooms or headings, the wear on brattice cloth is considerable, as mine cars, machines, and personnel constantly pass under the curtains which last only a few days or a few weeks in an active part of the mine. For such purposes tightly woven smooth cloth is desirable, so that it will not be easily torn. Curtains should not be used back from the working places, as they sometimes are, to deflect the main. split, as the leakage of air is too great. Doors should be used in such places."

May 1, 1928

By J. D. Tolman

In view of present interest in a revival of gold mining enterprises, papers dealing with the development of small gold properties are apropos. The present paper deals with the operation of a small gold property in the exploration and development stage, mining and milling 25 tons of ore daily, and indicates what may he expected in the way of mining costs under northern climatic conditions, by practicing rigid economy, at a property where disproportionate overhead costs are unavoidable bacause of the small rate of production. The output of this prospect is treated in a small amalgamation plant which has been described in a previous circular.. HISTORY Prospecting in the district was begun in 1909, and by 1911 the adjoining mines, Hollinger and McIntyre, were in operation. Actual work was begun on the Rochester claim in July, 1922, and carried on through 1924. The property was closed until 1928 when the present company took it over, together with the other holdings of the Canadel Mining Co. A small mill was started as a pilot plant on March 24, 1929, and is still in operation.

Jan 1, 1931

By L. B. Berger

In this investigation, the ampoule type of carbon-monoxide (CO) detector which is manufactured under license of U. S. Patent 1,644,014 (October 4, 1927) was tested for sensitivity and reliability. This detector was devised primarily for examining the air of manholes and sewers for possible dangerous contamination with CO before workmen enter these places, but due to the simplicity of the device it may have a more general usage for examination of atmospheres which are known or suspected, to be contaminated with CO. Some of the suggested uses are the examination of the air in garages, tunnels, mines, around blast furnaces, gas plants, and in the home.

Jan 1, 1930

By S. H. Katz

In the Bureau of Mines investigations of respiratory apparatus, a laboratory study of dust respirators has been conducted, and the results will be published in detail as a technical paper. Many industrial dust respirators, and many fabrics and filtering materials were tested. The principal results of these tests, and the conclusions drawn from them, are presented below. Reference to the patent literature discloses numerous types of dust respirators, mostly based on the filter principle. The present study included only representative filter-type respirators, purchased on the market.

Jan 1, 1926

By P. C. Good

Tungsten metal in fused form and of high purity was prepared by reducing tungstic oxide with redistilled calcium metal in a heavy-walled sealed reactor. Alloys of tungsten with vanadium, molybdenum) chromium, columbium, and tantalum were prepared by coreduction of mixed metal oxides in the same manner. This work was undertaken by the Bureau of Mines to investigate new approaches for preparing tungsten and its alloys in high-purity form. The standard method of producing tungsten metal has been the reduction of tungstic oxides by hydrogen. The resulting metal powder is compacted, sintered, and fabricated by powder metallurgy methods. Long experience in this field has resulted in the development of a technology that (by careful control of the variables such as metal composition, particle size, and sinterng technique) is well adapted to producing wire and the small shapes usually prepared from tungsten metal.

Jan 1, 1961

By J. A. McAllister, H. G. Iverson, K. C. Dean

"INTRODUCTION During the course of the investigation of the occurrence of manganese deposits in the western United States, laboratory studies of concentration were conducted at the Salt Lake City station on a sample of ore from the Lake Valley mines of the Newalpitt Fluorspar Corp. of Deming, N. Mex. The ore was reported to be representative of the type that would be mined for mill feed. The sample tested was found to be amenable to beneficiation by ore-dressing methods for the production of products that, when sintered, assayed over 44 percent Mn.At the beginning of the investigation of manganese-ore beneficiation in December 1940, the only product marketable to Metals Reserve Company was ferrograde manganese grade B, the requirements for which follow: Mn, min., 48 percent; Fe, max., 7 percent; Si02, max., 10 percent; P, max., 0.18 percent; Al203, max., 6 percent; Zn, max., 1 percent, Al2O3,Later the specifications were modified gradually. As of May 15, 1943, manganese products were acceptable if they contained over 35 percent manganese and less than 3 percent zinc and 1 percent phosphorus. Prices were based upon material containing 48 percent manganese, 6.0 percent iron, and 11 percent silica plus alumina. Premiums were paid for manganese content in excess of 48 percent and iron content below 6 percent, penalties being imposed upon products containing less than 43 percent -manganese, or more than 6 percent iron, or more than 11 percent silica plus alumina. The specifications for commercial manganese further required that maximum particle size be 12 inches and that, 75 percent of the product be coarser than 20-mesh. Therefore, fine material such as table and flotation concentrates had to be nodulized or sintered. In addition, oarbcnate manganese ores were not acceptable unless calcined."

Feb 1, 1948

By G. A. Apell

Completion of 18 churn-drill holes totaling 2,218 feet and 3 diamond-drill holes aggregating 421.5 feet of drilling in the M.C. mine area, near Truman, Wis., provided information indicating the existence and trend of a zone of zinc mineralization extending for 1,000 feet west of the old M. C. shaft.

Jan 1, 1949

By F. R. Cattoir, T. A. Sullivan

Commercial uranium metal was electrore fined to a high- purity product using molten- salt electrolytes in an inert atmosphere cell . Electrorefined uranium that contained , after consolidation , less than 30 ppm of metallic impurities was prepared . A method of leaching the electrolyte crystals to remove the salts was developed . Cathode current efficiencies from 90 to 100 percent were obtained . Two molten- salt electrolytes were prepared and evaluated : (1 ) lithium chloride - potassium chloride - uranium trichloride and ( 2 ) sodium chloridepotassium chloride - uranium trichloride . Very little difference was found in the purity of the uranium metal produced in either system . The lithium chloride - potassium chloride - uranium tri - chloride electrolyte was preferable from an operational standpoint .

Jan 1, 1964

By J. N. Van Sant

Lignite mining in North Dakota was begun about 1884 to supply the domestic needs of settlers. Annual production has grown rather slowly but steadily, exceeding 3 million tons in 1950. The western part of the State has lignite reserves, amounting to 351 billion tons, underlying an area of 28,000 square miles. Contour strip mining has almost completely replaced underground mining as the method of production. Lignite is often found under rather shallow and easily removed overburden, and this is the primary reason for the change in mining practice. Current mining operations are conducted where the overburden is 30 to 70 feet thick. Contour strip mining results in high production rates, at present 27 to 56 tons per man-day. These high production rates result in relatively low production costs.

Jan 1, 1959

Develop an improved downhole geophone system with enhanced signal/noise ratio for collecting cross-hole seismic data used in tomographic reconstructions. Background The Bureau of Mines is conducting research in the use of cross-hole seismic tomography for detecting and monitoring leach solution flow during in situ mining. This technique requires the use of a downhole seismic energy source in one borehole and a downhole wall-locking receiver (geophone) in another borehole separated from the first by the region to be investigated. Bureau research personnel chose a commercially available air gun for use as the downhole seismic energy source. Unfortunately, commercially available downhole wall-locking geophones that the Bureau tested were difficult to operate in the field, often unreliable and generally inadequate in terms of their signal/noise ratio. Therefore, research personnel began to experiment with an alternative down-hole geophone design that could be used to collect adequate data in a wide variety of borehole and cross-hole field situations. Approach An attractive alternative geophone design would be one that would incorporate a pneumatically operated wall-locking system. As an integral part of the Bureau's existing field system, a portable, high- pressure/low-volume air compressor would have sufficient capacity to operate the air gun as well as several small high-pressure pneumatic linear actuators. This approach was the simplest and most compatible with the research activities being conducted at the site.

Jan 1, 1991

By G. St John Perrott

"The United States Bureau of Mines is cooperating with the State of Utah and the City of Salt Lake in an investigation of methods of abating the smoke nuisance in Salt Lake City. In the course of this work samples of the atmosphere have been collected and analyzed in an attempt to determine the part played by sulphur dioxide or smelter gases in polluting the air at Salt Lake City.A fairly wide-spread opinion exists in Salt Lake City that the smelters contribute appreciably to the smoke nuisance. The gases discharged from the smelter stacks are believed (1) to float over the city in a heavy blanket which prevents the smoke from rising, and (2) to unite with the water vapor in the air to form corrosive fogs injurious to health and property.The first of these theories seems untenable. If the gas did not mix with air it would sink, owing to its heavier specific gravity, and form a blanket an the earth. Actually, the gas diffuses rapidly in air and any part reaching Salt Take must he thoroughly diluted. Perhaps sulphur dioxide in sufficient concentration might aid in fog formation. The more obvious nuisance, however, would be the injury to health and vegetation.The Garfield smelter is 16 miles west of the city, The Murray smelter 8 miles south, and the Midvale smelter 12 miles south. Under normal operating conditions, a relatively small amount of solid matter is discharged from these stacks. The toxic gaseous constituent of the discharge is sulphur dioxide, it is being discharged from the smelters the year round. If they are a factor in the city's smoke problem, the concentration of this gas in the air of the city should be appreciable and should increase toward the smelters, the con centration being highest with a south or a west wind."

May 1, 1920

By Louis A. Panek

The practice of roof bolting or rock bolting to stabilize rock surrounding underground excavations has increased tremendously within a few years. This widespread application has led to many questions concerning the mechanics of bolting and has pointed up the need for a quantitative method of designing bolting systems. To answer these questions a research program was initiated to determine the principles of roof bolting. The first problem chosen for investigation was the use of bolts to reinforce bedded roof, since the great majority of bolts are used under these conditions. The attack employed is a combination of theoretical and experimental stress analysis. Centrifugal testing of models was chosen as the experimental method because it is particularly suited to the study of stratified roof. This report describes the models, the experimental method, and the model-prototype relations. By using dimensional analysis, a general expression for a roof-bolting design formula in terms of the structural variables has been obtained. Certain model-prototype similarity requirements have been relaxed, thereby minimizing the number of variables to be studied and extending the applicability of quantitative test data to a large class of full size structures.

Jan 1, 1956

By Thomas Varley

Data on the consumption of reagents used in flotation during the years 1923 and 1924, in metallurgical plants in the Unites States, are presented in this paper. Two previous reports Lave been issued by the Bureau of Mines on consumption of oils and other reagents used to flotation - namely, "Statement of Flotation Oils," by O. C. Ralston, issued in 1913, and Serial No. 2203, "Consumption of Reagents Used in Flotation," by Thomas Varley, for the year 1919, issued in January, 1921.

Jan 1, 1925

By Steven W. Schmauch

In 1985, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied 27,930 acres of the 52,000 acre East Fork High Rock Canyon Wilderness Study Area, CA-020-914/NV-020-006A, in order to evaluate the mineral resources. The study area is located in Humboldt and Washoe Counties, NV, about 45 miles east of Cedarville, CA. Bureau of Mines personnel reviewed pertinent literature and county mining records and examined prospects or mineralized areas. There are no organized mining districts and no historical or active claims in the study area; one small pit lies in the southwest corner of the study area. Based on published literature, sample results and field observations, there are no recognized mineral, geothermal, or fossil fuel resources. Epithermal mineralization indicators are not present or exposed. Sand and gravel deposits in the study area are not likely to be developed as other deposits are closer to market areas.

Jan 1, 1986

Provide a full-scale test facility where the effectiveness of all types of subsidence abatement techniques can be evaluated under controlled conditions. Background Subsidence is ground movement resulting from the collapse of overlying strata into a mine void because of failure of the mine roof, mine floor, or support pillars. The failure may propagate to the surface and be expressed as a depression, cracks, or a sinkhole. The surface expression of such features may be delayed until long after mining has been completed. Subsidence has the potential to affect more land area than any other type of abandoned mine land problem. Subsidence also causes direct damage to real property, with significant financial loss and more importantly, presents a danger to public health, safety, and general welfare. Subsidence-related problems are considered to be one of the most important abandoned mine land issues. Backfilling of mine voids is the most common stabilization method used to abate subsidence and protect surface structures. Backfilling or placement of material is performed by hydraulic flushing or pneumatic stowing, using either in-mine or remote methods. The majority of the past subsidence abatement projects has been performed using remote methods from single or multiple boreholes. Other subsidence abatement techniques arc available. For example, various point support methods are used to protect small areas of the land surface and surface structures, without completely filling the mine void. These may be more appropriate under different conditions. Little documented information is available concerning the capability of the various backfilling methods for completely filling a mine void or providing long-term structural strength. Therefore, the Bureau of Mines developed a laboratory for controlled evaluation of backfilling technologies.

Jan 1, 1991

By Vernon C. Allison

The explosibility of coal dust has long been recognized by competent investigators as constituting one of the dangers of mining coal and in the use of pulverized coal as a fuel in industrial plants. The Bureau of Mines has carried on extensive series of experiments dealing with this subject, and has not only developed methods for the practical prevention of this danger, but in the, course of these experiments has developed a standard method of determining the relative explosibility of coal dusts and other organic dusts.3 Oil shale contains compounds 'of carbon and hydrogen that are either of a petroleum nature and are strongly ,adsorbed upon the incombustible part of the shale, or else are present in the shale as a compound ("kerogen") which has the property of changing into petroleum-like products when acted upon by heat. The oil shales may contain varying amounts of the organic matter, ranging from a trace to more than 66 per cent, depending upon their richness; therefore, it is important to know whether the dusts formed in mining and handling these oil shales are explosive when mixed with air and if so, to indicate remedial measures. This paper gives the results of explosibility tests of several pulverized oil shale's, selected as being typical of those which in the future may be used in commercial shale-oil production test on a sample of typical Colorado oil shale has been., published in an earlier paper.4

Jan 1, 1926