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By Stephen R. Iverson

Mineral deposits examined in and near the Raywood Flats RARE II area have low potential for development. The Mill Creek Mine (fig. 1), has produced about 14,000 tons (13,000 t) of marble, and another 5.5 million tons (5.0 million t) of marginal marble reserves suitable for lime, chemicals, and cement production are estimated to remain at this deposit. However, nearly all the marble is outside the study area. The deposit is marginal because alternate sources of marble are closer to markets. A tungsten occurrence in the marble is too small and low grade to be considered a resource. Ten tons (9.1 t) of uranium- and thorium-bearing material have been mined from a pegmatite dike at the St. Patrick Mine. However, this occurrence also is too small and low grade to be considered a resource. More than 400 lode and placer claims have been located in or near the study area. There are no current claims or mineral, oil and gas or geothermal leases.

Jan 1, 1983

By David A. Lipton

U.S. Bureau of Mines personnel examined mines, prospects, and mineralized areas to determine the mineral resources and potential of the Moses and Dennison Peak RARE II areas in Tulare County, California. These areas, along the west slope of the Sierra Nevada, are underlain by grarnitic rocks of the Sierra Nevada batholith and contain numerous metasedimentary roof pendants. Silver, copper, and zinc occur in contact-metasomatic deposits within the metasedimentary rocks. In the Moses area, the Powell Mine (fig. 1) contains an estimated 90,000 tons (82,000 t) of subeconomic silver, zinc, and copper resources. The King Solomon Prospect has 3,000 tons (2,700 t) of silicified phyllite containing zinc. On the Helen-Joyce Prospect, 44,000 tons (40,000 t) of gossan occur above a poorly exposed silver-zinc rich zone. Potential exists for additional mineral resources and occurrences at each of these properties.

Jan 1, 1983

By Bradley V. Johnson

This publication summarizes the in-house and contract research and development projects conducted since 1974 by the Bureau of Mines for the control of noise and vibrations from surface mine blasting.

Jan 1, 1982

By Fred N. Kissell

This handbook describes effective methods for the control of methane gas in mines and tunnels. It assumes the reader is familiar with mining. The first chapter covers facts about methane important to mine safety, such as the explosibility of gas mixtures. The second chapter covers methane sampling, which is crucial because many methane explosions have been attributed to sampling deficiencies. Subsequent chapters describe methane control methods for different kinds of mines and mining equipment, primarily for U.S. coal mines. These coal mine chapters include continuous miners and longwalls, including bleeders. Coal seam degasification is covered extensively. Other coal mine chapters deal with methane emission forecasting and predicting the excess gas from troublesome geologic features like faults. Additional coal chapters contain methane controls for shaft sinking and shaft filling, for surface highwall mines, and for coal storage silos. Major coal mine explosion disasters have always involved the combustion of coal dust, originally triggered by methane. Thus, a chapter is included on making coal dust inert so it cannot explode. Methane is surprisingly common in metal and nonmetal mines around the world, as well as in many tunnels as they are excavated. Accordingly, a chapter is included on metal and nonmetal mines and another on tunnels. Proper ventilation plays the major role in keeping mines free of hazardous methane accumulations. The ventilation discussed in this handbook, except for the chapter on bleeder systems, deals only with so-called face ventilation, i.e., ventilation of the immediate working face area, not ventilation of the mine as a whole. The omission of whole-mine ventilation was necessary to keep this handbook to a reasonable size and because a huge amount of excellent information is available on the subject.2

Jan 1, 2006

By Etienne Audibert

No satisfactory theory has yet been advanced to explain what takes place when an explosive is fired in a mixture of firedamp and air. The only means of measuring the' danger is to fire the explosive into the gas mixture and note the effect, but the conditions of firing must be chosen carefully. This report is presented in the hope that it will assist in determining what method to use. The experiments have been designed to show the effect of the principal factors involved in the conditions of firing, and the results give information that seems to have some value.

Jan 1, 1940

By Virgil Miller

Bureau of Mines Reports of Investigations 3244, 3245, 3246 and 3264 give data of detailed studies on smelting in the lead blast furnace handling zinciferous charges at Trail, B. C. The present paper gives more on analyses of the gases leaving the top of the charge and on accretions formed on the walls of the blast furnace. New data are presented to show the effect of the temperatures at the tuyere zone on the lead content of the slags made. The greater part of this paper, however, deals with a much debated subject, namely air used in lead blast furnaces. Original data are presented to show the effects on smelting lead 'products when air is supplied to a lead blast furnace under volume versus under pressure control.

Jan 1, 1940

By Virgil Miller

Bureau of Mines Reports of Investigations 3244, 3245, 3246 and 3264 give data of detailed studies on smelting in the lead "blast furnace handling zinciferous charges at Trail, B. C. The present paper gives more on analyses of the gases leaving the top of the charge and on accretions formed on the walls of the blast furnace. New data are presented to show the effect of the temperatures at the tuyere zone on the lead content of the slags made. The greater part of this paper, however, deals with a much debated subject, namely air used in lead blast furnaces. Original data are presented to show the effects on smelting lead 'products when air is supplied to a lead blast furnace under volume versus under pressure control.

Jan 1, 1940

By H. R. Babitzke

The purpose of this investigation was to develop an alloy of columbium for use at high temperatures and for nuclear applications. The properties of possible alloys were determined, and the more promising ones were selected for further improvement. Criteria for selection were machinability, hardness, workability, tensile strength, and oxidation resistance. Thirteen 100-gram ingots, ranging from 100 percent columbium to 100 percent vanadium, were prepared and subjected to various tests. Also included for comparison were zirconium and the zirconium alloy, zircaloy-2. Test results showed that a columbium alloy, containing 10 atomic percent vanadium merits further development. Besides being workable at room temperature, the columbium-10 atomic percent vanadium alloy has oxidation resistance superior to the other alloys of the series and is also superior to zirconium or zircaloy-2. The latter two materials have comparable neutron-absorption cross sections. The strength and hardness values of the alloys tested were found to increase with increasing vanadium content, reaching a maximum at 50 atomic percent vanadium and decreasing with further increase in vanadium. This behavior is typical of binary alloys wherein each element will retain any proportion of the other in solid solution. INTRODUCTION There is an increasing need for alloys for service at high temperatures. Since current world reserves of columbium metal approximate 1,500,000 tons (1),4 this metal is now readily available. Columbium can ties; be considered a practical base material for high-temperature alloys required in nuclear reactors and in aircraft and space vehicles. General requirements chosen are: (1) Workability, (2) satisfactory mechanical properties at temperatures approaching 1,000° C., and (3) resistance to oxidation at such temperatures.

Jan 1, 1962

By Verne E. Hooker

Near-surface temperature measurements in two granite quarries show that diurnal temperature variations are significant to a depth of 1 or 2 feet, and annual temperature variations are significant to a depth of at least 25 feet. As a result, ground stress anomalies due to temperature exist near the surface, and their magnitude depends upon the time of day and the time of year. Rock stress and corresponding temperature measurements were made in one granite quarry over a rock temperature range of 33° to 81° F. Measured rock temperatures show good agreement with values predicted from one-dimensional heat flow theory. Calculated and measured stress-temperature coefficients for the two granites in this study are given. Thermally induced stress variations in near-surface rocks tested were as large as 1,690 psi from combined daily and seasonal temperature changes.

Jan 1, 1971

By Etienne Audibert

No satisfactory theory has yet been advanced to explain what takes place when an explosive is fired in a mixture of firedamp and air. The only means of measuring the danger is to fire the explosive into the gas mixture and note the effect, but the conditions of firing must be chosen carefully. This report is presented in the hope that it will assist in determining what method to use. The experiments have been designed to show the effect of the principal factors involved in the conditions of firing, and the results give information that seems to have some value.

Jan 1, 1940

By Fredrick L. Johnson

No mineral resources were identified during the investigation of the White Cloud-Boulder RARE II area. Only a few claims have been located in the area and only two workings were found. However, there has been considerable exploration and mining activity near the RARE II area. Sand and gravel resources are abundant but similar deposits occur closer to market areas. There are no known coal, oil, or gas deposits. Most of the RARE II area is underlain by volcanic rocks. The likeliest host rocks for metallic minerals are the metasedimentary rocks exposed in the south part of the area; there is potential for zinc and silver resources at a prospect in that part. Traces of scheelite and powellite were observed in the Kent Peak-Ryan Peak area along hair-line fractures in calcareous country rock. While no significant concentrations of the minerals were found, their presence, a northwest alignment of prospects with similar deposits, and an abundance of dikes near the deposits, suggest that the intrusive system (Summit Creek stock) exposed near the head of Little Fall Creek may extend to the northwest under the RARE II area.

Jan 1, 1983

By J. E. Crawshaw

"The few previous observations of the effect of turbulence on limits of inflammability have been made on a small scale in turbulence produced either by a fan or by movement of the mixture.By a suitable amount of turbulence from a fan the lower limit of methane was 5 per cent as compared with 5 per cent observed for quiescent mixtures in the same vessel.3 With a streaming movement of the gas mixture within the range of speed from 35 to 65 centimeters per second (69 to 128 feet a minute) the lower limit was approximately 5 percent,4 For a quiescent mixture of ethane the lower limit was 3.10 per cent ethane, but with fan running at a moderate speed a 3 per cent mixture exploded.5The object of the tests herein reported was (1) to determine the lower limit of natural gas in a mixture of natural gas and air Which would be ignited and propagate violently when the turbulence was produced by explosives fired from a cannon into the mixture; (2) to observe the behavior when the mixture contained less than this low limit; and (3) to determine how turbulence produced by a fan affects thin limit.Four series of tests were run, three of which were to determine the effect of different sources of ignition: Tests with (1) an electric igniter; (2) 3F black blasting powder stemmed with 2 pounds of dry fire clay stemming used to ignite the mixture, and (3) 40 per cent straight nitroglycerin dynamite unstemmed. The fourth was made to study the effect of turbulence produced by a two-speed electric fan, using an electric igniter as the source of ignition.In both series of tests with explosives, charges of 50 and 200 were used to determine the effect of increased quantity of explosives on the lower limit of natural gas."

Jul 1, 1930

By Annie G. Smelley

As part of its program to develop technology that will encourage maximum utilization of the Nation's mineral resources, the Bureau of Mines conducted research on debrining potash-clay waste slurries by means of flocculation with a high-molecular-weight polymer and subsequent solid-liquid separation on a rotating trommel screen. In laboratory batch tests, potash-clay waste slurries were consolidated from initial clay contents of 8 pct to final contents of 30 pct with a polymer dosage of 1.2 Ib/ton of dry clay waste. Small-scale continuous tests yielded debrined products containing 20 pct solids using a polymer dosage of 1 Ib/ton of dry clay solids.

Jan 1, 1983

By J. P. McGee

The Bureau of Mines is doing research and development work on a coal-fired gas turbine plant initially developed by the Locomotive Development Committee, (LDC) of Bituminous Coal Research, Inc. The Bureau is redesigning the turbine blading and some of the auxiliary equipment, and is reerecting, the plant at the Morgantown (W. Va.) Coal Research Center. The present goal is a 1,500-hour run at virtually the same operating conditions used by the LDC in their final 1,100-hour test with the turbine. This will allow the Bureau to properly evaluate the new blade design. Erosion of the turbine blades (particularly the roots) by ash in the hot gases from the combustion of coal was the most serious problem in extended operation in earlier experimental work. New blades made of Stellite6 are being fabricated for the stator and rotor, and armored wear strips of titanium carbide will be inserted in the blades at the areas of probable maximum ash velocity and concentration. The trailing edges of the rotor and stator blades are being thickened and thinned, respectively, to induce the ash to travel to the casing and prevent it from returning to the base of the rotor blades. The first stage rotor and second stage stator blades are being removed to provide an annular space for maximum quantities of coal ash to centrifuge to the casing. Additional blades will be added to most of the rows in the stator to stop secondary flow of dust-laden gas toward the rotor. A contract has been awarded for fabrication of the new blades. The 1,500-hour run will be started as soon as the new blades are installed.

Jan 1, 1962

By R. D. Leitch

"INTRODUCTION The character of mine drainage from areas of low pyritic coal3 and from average pyritic coal4 has been investigated, and to complete the study it seemed desirable to select a number of mines situated in high pyritic are as to determine whether or not this variation determines the relative acidity of drainage from mines operating in these characteristic coal fields. Advantage has been taken of some worked on in 1918 by Henry Leighton 5, then Professor of Economic Geology, University of Pittsburgh. He visited and has reported certain areas of high pyritic coal which we also visited during this study. Many of the mines were found to be idle in 1930 and a few were caved shut, apparently for several years. However, samples of the outflow from all mines visited were collected if possible and analyzed, and some general information was gathered for each mine. The map (fig. 1) shows the location of these areas as given by Leighton.ACKNOWLEDGMENTSThe information and assistance obtained from officials and others at the mines visited during this study are gratefully acknowledged, as well as the original suggestion from Dr. Glenn V. Brown of the State Sanitary Water Board who called attention to the desirability of such a study.Thanks are also especially due the coal laboratory of the United States Bureau of Mines, under the direction of H. M. Cooper, for the analyses and determination of sulphur forms in the large number of solid samples necessary to the work reported,This study has been carried on under the direction of R. R. Sayers, chief, health and safety branch, and W. P. Yant, supervising engineer, Pittsburgh Experiment Station, of the U. S. Bureau of Mines."

Jan 1, 1932

By G. S. Scott

In the course of the Bureau of Mines investigation relative to the causes, behavior, and control f anthracite-mine fires, attention was directed toward the correlation between the temperature of oxidation and the gaseous oxidation products in the range of temperatures between 100° and 350°C4/ These tests, made on a high-grade anthracite to determine the amount of oxygen consumed and the amounts of carbon dioxide, carbon monoxide, hydrogen and methane evolved when air was passed through samples of the anthracite at various elevated temperatures, showed that the gases evolved and their relative proportions vary with temperature, constitute a means for determining the probable temperature of the anthracite, and thus permit detection of incipient heating before a dangerous fire hazard exists. As the relationships mentioned are affected somewhat by the amount of previous oxidation of the coal, it was deemed desirable to know to what extent they might vary owing to this cause. It was also considered desirable to have a means for estimating the extent of oxidation from the gas analysis, as this would permit a more accurate estimate of probable temperature. Finally, it seemed desirable to know how much the composition of coal might vary over an extended period of oxidation, since this was previously suggested5/ as a possible means for estimating the probable maximum oxidation temperature to which a sample of coal had been subjected.

Jan 1, 1940

By G. S. Scott

In the course of the Bureau of Mines investigation relative to the causes, behavior, and control of anthracite-mine fires, attention was directed toward the correlation between the temperature of oxidation and the gaseous oxidation products in the range of temperatures between 100° and 350°C4/. These tests, made on a high-grade anthracite to determine the amount of oxygen consumed and the mounts of carbon dioxide, carbon monoxide, hydrogen and methane evolved when air was passed through samples of the anthracite at various elevated temperatures, showed that the gases evolved and their relative proportions vary with temperature, constitute a means for determining the probable temperature of the anthracite, and thus permit detection of incipient heating beers dangerous fire hazard exists. As the relationships mentioned are affected somewhat by the amount of previous oxidation of the coal, it was deemed desirable to know to what extent they might vary owing to this cause. It was also considered desirable to have a means for estimating the extent of oxidation from the gas analysis, as this would permit a more accurate estimate of probable temperature. Finally, it seemed desirable to know how much the composition of coal might vary over an extended period of oxidation, since this was previously suggested5/ as a possible means for estimating the probable maximum oxidation temperature to which a sample of coal had been subjected.

Jan 1, 1940

By Stephen Gerard Sawyer

This report presents a Fortran IV computer program for the structural analysis of space-frame protective canopies used in underground mines to protect equipment operators from falls of roof, face, or rib. This program entitled CANOPY permits rapid calculation of the elastic strength of a canopy for a variety of static loading conditions. Stresses in, and displacements of each structural member are computed and printed out. Additionally, identification of all members that have commenced yielding, weight of the canopy, total loads on the canopy, and maximum loads that the canopy can sustain elastically are output. Program description, input instructions, program listing, and two example problems are included.

Jan 1, 1972

By J. J. Lukasko

The U.S. Bureau of Mines developed an alternative electrochemical process for the production of calcium metal. The current industrial practice is costly, complex, and inefficient. The Bureau method involved electrowinning of a calcium-tin alloy followed by electrorefining to produce calcium metal. In the electrowinning cell, CaCI2 was fed to a KCI2-CaCI2 electrolyte. The calcium was electrowon at 6500 C into the pure molten tin cathode until the cathode contained 7.5 wt pct Ca. Current efficiency for electrowinning averaged over 90 pct. The resulting calcium-tin alloy served as the anode for the electrorefming cell, which employed a [CaC~-CaF2] fused salt as the electrolyte. Calcium metal was electrorefmed at 8500 C with a current efficiency of 85 pct based on calcium metal recovered. The calcium metal analyzed 99.2 pct, which is purer than commercially produced calcium.

Jan 1, 1990

By John C. Nigro

This Bureau of Mines report summarizes the performance characteristics of a 30-day around-the-clock gasification-pelletizing test conducted in October and November of 1980 with North Dakota Indianhead lignite. Gasification was conducted in a commercial-size, 6.5-it-diam, Single-stage, fixed-bed, atmospheric pressure producer with a rated capacity of about 30 million Btu/hr. Iron oxide pellets made from a commercial hematite concentrate were fired with the low-Btu gas in a 2.8-ft-diam by 35-ft-long pilot plant rotary kiln at a rate of 900 lb of pellets per hour. Gasifier operations at fuel feed rates up to 3 tons of lignite per hour and hematite pellet induration with raw 160-Btu/std ft3 lignite gas are described.

Jan 1, 1982