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By Elmer W. Pehrson

The recent establishment of an official price of 64.64 cents per ounce for silver by the President's order of December 21, 1933, has provoked discussion as to the effects of this move on the various metal-mining industries. To assist those of the mineral industry who are interested in this problem, the Bureau of Mines presents the following analysis of basic statistical data concerning; the relation of the silver price to the value of copper ores mined in the United States. The term "copper ore" as used herein includes all ores in which copper is the most abundant base metal paid for. In 1928, this class of ore contributed 98 percent of the total copper output of the United States.

Jan 1, 1934

By Frank G. Horino

The Bureau of Mines studied the uniaxial compressive strength of model rock pillars as a function of the angle and spacing of noncohesive planes of weakness. The model pillars were prepared from NX 2-l/8-inch diameter drill core of limestone, sandstone, and granite, and the planes of weakness were diamond saw cuts ground flat and smooth. The angle of the planes of weakness, measured from the horizontal, varied from zero to 57° in approximately 15° increments. When two planes of weakness were used, the thickness-to-diameter ratio of the wafer was 1/4, 1/2, and 1, Approximately 400 model pillars were tested in uniaxial compression. The results indicate that the uniaxial compressive strength of model pillars decreases rapidly as the angle of the plane of weakness increases from 30° to 57°, and that the spacing of these planes of weakness has only a minor effect on the strength. The effect of the number of horizontal planes of weakness, with a spacing of 1/4 and 1/2 of the diameter, upon the compressive strength of model pillars was also investigated. These results indicate that as the number of planes of weakness increases the compressive strength of the pillar decreases. Normalizing the data provides useful estimates of model pillar strengths for any rock type.

Jan 1, 1968

By Seth C. Schaefer

The Bureau of Mines has determined the standard Gibbs energies (AGf°) of CoS1.035 (cobalt sulfide) and Ni2.515S2 (nickel sulfide) with high-temperature galvanic cells using stabilized Zr02 (zirconia) as the electrolyte. Potential measurements were obtained for the cell Pt, CoS1.035, CoO, S02(g, 1 atm)//Zr02//02(g, 0.0114 atm), Pt, with the overall cell reaction C0S1.035(c) + 1.535 02(g, 0.0114 atm) = CoO(c) + 1.035 S02(g)¬ These results, combined with the best available data for ?Gf° of CoO and S02 from the literature, give the standard Gibbs energy of formation of CoS1.035 for the reaction Co(c) + 0 5175 S2(g) = CoS1.035(c) ?Gf° = -38.890 + 18.87 x 10-3T ± 0.185 kcal/mole (866.0 - 1,104.9 K), where temperature (T) is expressed in kelvins. Similar measurements were obtained for the cell Pt, N12.515S2, NiO, S02(g, 1 atm)//Zr02//02(g, 0.0122 atm), Pt, with the overall cell reaction Ni2.515S2(c) + 3.2575 02(g, 0.0122 atm) = 2.515 NiO(c) + 2 S02(g). Combination of these results with data for ?Gfo of NiO and S02 from the literature yields the standard Gibbs energy of formation of Ni2.515S2 for the reaction 2.515 Ni(c) + S2(g) = Ni2.S1SS2(c) ?Gf° -65.377 + 24.67 x 10-3T ± 0.541 kcal/mole (968.6 -1,053.7 K).

Jan 1, 1981

By Seth C. Schaefer

The Bureau of Mines studied thermodynamic properties of liquid Al-Si alloys with the high-temperature galvanic cell Al(1)//Al+3(AlC13 in NaCl?KCl)//Al-Si alloy(1). Activities of aluminum and silicon (referred to pure liquid metals) show a pronounced negative deviation from Raoult's law in liquid Al-Si alloys containing 0.9 to 35.2 atomic-percent silicon. Activity coefficients and the properties [?Gi, ?GxS ,?H, ?G, ?Gxs , and ?S] have been derived from the experimental data and are summarized in tables and illustrations.

Jan 1, 1974

By Arcy, D&apos Banister

Drilling practices at the Silver Summit mine in Shoshone County, Idaho, and the steps taken to increase drilling efficiency are described for the 1952 to 1958 operating period. Mining and development methods are outlined, and drilling equipment and practice are discussed. Cost and performance data include drilling time, bit duty, steel failure, drill repair, and compressed-air consumption. Steps taken to increase drilling efficiency and decrease costs are described, including modifications of bit design, new procedures for drill-rod fabrication and new processes for completing certain drill-machine repairs.

Jan 1, 1963

The Bureau of Mines evaluated short-delay coal mine detonators manu-factured by three domestic companies for electrostatic sensitivity, strength, and no-fire current level. Electrostatic sensitivity was studied in pin-to-pin and pin-to-case modes employing lO-kV potential. Strength of detonation was measured in the Bureau's underwater test fa-cility. No-fire current was measured using a constant-current power supply unit. Test procedures and experimental data are included.

Jan 1, 1985

By Arcy, D&apos Banister

Drilling practices at the Silver Summit mine in Shoshone County, Idaho, and the steps taken to increase drilling efficiency are described for the 1952 to 1958 operating period. Mining and development methods are outlined, and drilling equipment and practice are discussed, Cost and performance data include drilling time, bit duty, steel failure, drill repair, and compressed-air consumption. Steps taken to increase drilling efficiency and decrease costs are described, including modifications of bit design, new procedures for drill-rod fabrication and new processes for completing certain drill-machine repairs.

Jan 1, 1963

By K. O. Bennington

Thermodynamic properties were determined by the Federal Bureau of Mines for lithium metasilicate (Li2Si03) and lithium disilicate (Li2Si205). Their enthalpies of formation were investigated by hydrofluoric acid solution calorimetry. The standard values are ?Hf°298 -393.8 ± 0.8 kcal/mole for Li2Si03, and ?Hf°298 -611.8 ± 1.0 kcal/mole for LiSi205. Enthalpy increments above 298 K were measured by copper-block drop calorimetry from 298 to 1,404 K for Li2Si03, and from 298 to 1,281 K for Li2Si205. Low-temperature heat capacities were determined adiabatically from 6 to 305 K for Li2Si205 only. The derived standard entropy is S°298 = 29.20 ± 0.10 cal/deg-mole. The various experimental data were combined with other data from the literature, and resulting properties of ?Hf°, ?Gf°, and log Kf were tabulated as a function of temperature.

Jan 1, 1976

By Howard P. Hamlin, John W. Sweeney

Shales from 14 locations in Indiana were sampled , tested , and evaluated to determine feasibility of producing lightweight aggregates by rotary - kiln and sintering methods . Sampling procedures and the geology of the significant shale units are discussed . Preliminary testing was conducted in a muffle furnace , and continuous tests were made in a 16 - inch by 14 - foot rotary kiln . The aggregate weighed 37.0 to 47.2 pounds per cubic foot . Concrete cubes employing the aggregate were tested to determine the qualities of the concrete . Compressive strength of the concrete using seven bags of cement per cubic yard , after autoclave curing for 6 hours , ranged from 3,600 to 5,850 pounds per square inch . Four samples made suitable lightweight aggregate in the laboratory rotary kiln . Four samples tested by sintering methods made unsatisfactory aggregate .

Jan 1, 1965

By L. R. Burdick

This paper presents a review of published investigation dealing with the importance of sulfur compounds in the deterioration of materials or providing some basis for estimating the extent of loss shareable to such air pollution. Materials included are cement, stone, metals, paint, leather, paper, sand cloth. The investigations may be divided into two classes, one of the laboratory type in which the sulfur content and the humidity of the air were controlled and the other dealing with the exposure of materials to atmospheres not under control. The first type of work has shown that cement is subject to deterioration by the action of sulfur dioxide gas. The experiments with stone indicate that although limestone takes up sulfur dioxide, from the air, moist sulfur dioxide-air mixtures alone cannot be used for establishing- the comparative weathering- qualities of the different types of stone by accelerated test methods. Laboratory tests indicate that sulfur compounds in the air accelerate the corrosion of iron, steel, zinc, copper, and nickel at normal air temperatures and at certain relative humidities. It has also been indicated that certain types of paint are, affected by high sulfur dioxide concentrations, and that paper is attacked by sulfur dioxide in the atmosphere. The investigations of the second type show the amount or variation of corrosion in different localities and under different types of exposure. The investigations (10) (18)4/ during which sulfur determinations were made indicate that sulfur dioxide is a main controlling factor in the corrosion of iron and steel but according to Quick (18) may not be for some nonferrous metals. In general, the laboratory tests do not Jive definite data on the loss due to sulfur compounds at the concentrations normally found in the air. The data from atmospheric exposures are not complete from the standpoint of the exact effect of the sulfur compounds. Damage to materials so exposed is affected by factors such as other chemical contaminants, humidity, rainfall, solid deposits, and sunlight. A simple scheme has been devised in Great Britain which is considered to provide a measure of the attack of sulfur compound, on building materials (1). Small cylinders coated

Jan 1, 1939

By R. J. Matetic

The objective of this U.S. Bureau of Mines hydrologic-subsidence investigation was to evaluate the effects of longwall mining on the local ground water regime through field monitoring and numerical modeling. Field data were obtained from multiple-position borehole extensometers (MPBX's) that were used to measure subsurface displacements. Survey monuments were installed to measure mining-induced surface deformations. Numerous drawdown and recovery tests were performed to characterize hydrologic properties of the overburden strata. Coreholes were drilled above the study area to determine lithologic and strength characteristics of the overburden strata using the rock samples collected. Electronic recorders were installed on all monitoring wells to continuously monitor ground water levels in coordination with mining of the longwall panels. A combined finite element model of the deformation of overlying strata, and it's influence on ground water flow was used to define the change in local and regional water budgets. The predicted effects of the postmining ground water system determined by the model correlated well with field data collected from the fieldsite. Without an infiltration rate added to the model, a static decrease of 3.0 m (10 ft) in water level would occur due to mining of both longwall panels and if an infiltration rate was inputted in the model, no predicted long-term effects would occur to the ground water system.

Jan 1, 2010

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 16 September to 1 November 1983. The testing covered herein is for coarse 2-in by a (minus 50 mm) Pittsburgh Seam coal in a 12-in (3 00 mm) pipeline, at velocities ranging from 5 to 18 ft/s (1.5 to 5.5 m/s) and at concentrations ranging from 15 to 55 pct.

Jan 1, 1985

By S. J. Aresco

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 composition as shown by proximate analyses. To these, when required, are added the ash-softening temperature, the free-swelling index, and the Hardgrove grind-ability index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions4 issued by the Bureau of Mines; the samples are analyzed in the Bureau laboratory to determine whether the coal is of the quality guaranteed by the contractor; if it is not, a price adjustment is made. Analyses of the delivered coal and tipple samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. In addition, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.

Jan 1, 1965

By W. H. Blackburn

This paper describing the milling practice at the Tybo concentrator is one of a series of similar papers being prepared by the United States Bureau of Mines on milling methods and costs at the various mills in the United States. ACKNOWLEDGMENT A large part of this paper way prepared by H. M. Lewers, mill superintendent of the Tybo plant of the Treadwell Yukon Co., Ltd.

Jan 1, 1931

By Terry S. Cory

This report is a comprehensive summary of the results of the propagation measurements program conducted for the US Bureau of Mines under Contract H0366028. Data was gathered in the MF frequency range from a cross sample of six mines representative of the industry having typical wireless requirements. From the raw data which was gathered, a logical method of data reduction is presented which culminates in a set of average attenuation characteristics for all mines visited. These characteristics define a typical MF wireless system when the communication range requirements are known. Direct through-the-earth propagation and the range enhancement mechanism due to coupling on and off conductors are evaluated and related to the planning of a typical wireless MF communications system.

Jan 8, 1977

By W. D. Mcmillan

Although the Shafter district of Presidio County, Tex., is principally renowned for silver production from the Presidio mine, the occurrence of lead-zinc ores in the western part of the district has been known for at least 50 years, and there has been some production. An area of about 3 square miles in the vicinity of an extending westward from the Presidio mine was investigated in detail by C. P. Ross of the Federal Geological Survey in 1934. In the fall of 1943, A. B. Needham, an engineer of the Bureau of Mines, called the attention of the Geological Survey to the area west of that included in Ross's map, and requested a detailed investigation of that area by the Survey in advance of development by the Bureau of Mines. After a brief reconnaissance by the Survey in the spring of 1944, detailed studies were made by Federal geologists in the summer of 1944, during which about 450 acres were surveyed, on a scale of 1 inch to 100 feet. Recommendations for the exploration of certain parts of the area were made in the accompanying report.

Jan 1, 1949

By Jaffrey Y. Foley

Placer gold and platinum-group metals (PGM) In the Slate Creek area, northern Chistochina Mining District, are derived from silicified and carbonate-altered, Cretaceous-Tertiary (?) dikes and related mafic and ultramafic rocks. Gold In the placer deposits is also derived from Tertiary conglomerate and altered Jurassic-Cretaceous argilllte. The argilllte and Igneous bedrock sources show a unique Ag-Au-Cu-Hg-PGM association that Is attributed to a combination of magmatic, hydrothermal, and supergene processes. The bedrock and placer deposits contain a variety of gold silver-lead-copper and PGM alloys. The observed geochemical, mineralogic, and alteration features are consistent with current geological models for turbidite-hosted gold deposits. No economic gold or PGM lodes were Identified, but several areas warranting more detailed investigation were Identified. Conventional geochemical sampling and analysis of small sample splits weighing between 10 and 30 grams were shown to be unreliable as a consistent means of identifying gold- and PGM-bearing bedrock. Pan concentration of pulverized rock samples was shown to be a more effective, but still Imperfect means of Identifying gold and PGM source rocks. Geochemical data and mineralogic examination indicate that gold and PGM in potential lode sources are very finely and erratically disseminated, are chemically combined with other elements, and may not be entirely free-milling or amenable to simple gravity concentration.

Jan 1, 1990

By C. E. Henning

The total number of petroleum refineries in the United States on January 1, 1958, was 318 and their total crude-oil throughput capacity was 9,407,707 barrels per day, according to the Bureau of Mines annual survey. During 1957, 3 new refineries began operating while 4 refineries were retired. Although there was 1 less refinery, the total crude-oil throughput capacity at the beginning of 1958 was 284,033 barrels per day, or 3 percent, more than the January 1, 1957, level. During 1957 all refinery districts showed increases in capacity. The largest increase, 27 percent, occurred in the West Coast district followed by the Indiana-Illinois-Kentucky district with 14-percent increase and the Texas Gulf Coast district with 13-percent increase. The national increase in capacity had the effect of raising the capacity of the average refinery from 28,601 to 29,584 barrels per day. New crude-oil capacity under construction on January 1, 1958, totaled 185,265 barrels, and an additional 297,885 barrels capacity was reported building as replacement for existing facilities. Included in total new construction were 2 new refineries, 1 in Washington and another in Texas, with planned processing capacities of 45,000 barrels and 8,550 barrels per day, respectively.

Jan 1, 1958

By C. C. Blade

"This report on the properties of motor fuels sold through service stations ni the Unietd States is a continuation of a series of reports made in accordance with a cooperating agreement between the Coordinating Fuel Research (CRF) Committee of the Coordinating Research Council (CRC)3/ and the Bureau of Mines of the United States Department of the Interior. The first of these reports presented data on motor gasolines sold during the winter of 1935-36.4/ Further reports were issued describing motor gasolines sold during the succeeding summers and winters to and including the summer of 1941.4/ No reports were made on motor gasolines sold during the winter of 1941-42 and during the summer of 1942. However, starting with the winter of 1942-43, the semiannual reports were resumed.4/The present report presents analytical data for 1,381 samples, representing the products of approximately 75 companies. Most of the samples represented in this report were secured during July and the first half of August, 1945. As in previous surveys, the companies covered by the survey include both large and small suppliers. Conforming to former reports, the data cover three groups of samples – regular-price, premium-price, and third-grade gasolines.As the number of analyses submitted for samples of third-grade gasoline are not considered adequate to represent this type of motor fuel, data for the analyses have not been averaged, but the individual items are tabulated. The number of samples, items and brands comprising each group is as follows: Regular-price, 733 samples, 229 items, and 57 brands; premium-price, 504 samples, 197 items, and 56 brands; third-grade, 84 samples, 28 items and 12 brands. The meanings of these terms as sued in the surveys are as follows:"

Jan 1, 1946

By Raymond G. Travis

This report describes coal-mining methods, power requirements, coal production and distribution, and coal resources of the Bull Mountain coal field in Musselshell and Yellowstone Counties, south-central Montana Investigations in the field, were conducted by Bureau of Mines engineers The report contains a short summary of the geology and geography of the field and discusses the following information secured during the field study: Method of mining practiced at each mine, including a description of each phase of the mining cycle. Coal produced and its distribution at each mine. Power requirements and the consumption of electricity per ton of coal produced by mines. Number of non employed by mines, and the production per man per shift underground and the over-all production per man employed. Estimates of future production and power requirements for the field as a whole. This information should be of benefit to any company or individual planning the development of now coal mines in the area or the expansion of present operations.

Jan 1, 1950