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By C. W. Smith

The Bureau of Mines conducted laboratory-scale beneficiation tests on a sample of corundum gneiss from Montana to devise a method for beneficiating corundum for use as a substitute for refractory-grade bauxite. A flotation process utilizing petroleum sulfonate as the collector in an acid circuit was devised. Results showed that two flotation schemes each produced a concentrate exceeding the national stockpile specifications for calcined bauxite. From a feed containing 28 pct corundum concentrates containing up to 92.5 pct alumina (A1203) were produced with a corundum recovery of 78.5 pct.

Jan 1, 1987

By Russell R. Trengove

The Strawberry tungsten mine is in the Jackass Mining District, in an isolated portion of eastern Madera County, near the southeast corner of the Yosemite National Park. The deposit was discovered in 1941, and production started in 1943 when the mill was completed. With the exception of 1946 and 1947, production has been continuous. The area in the vicinity of the mine is granite containing islands of sedimentary beds highly altered by metamorphism that resulted from the intrusion of acid igneous rock. Schoelite occurs in almost vertical lenses of tactite between the limestone and the granite.

Jan 1, 1949

By Rees D. Groves

The Bureau of Mines conducted research on reactions of copper sulfide minerals with chlorine in an aqueous system. Selected samples of covellite, chalcopyrite, chalcocite, bornite, and pyrite were leached with aqueous chlorine solutions. The mineral samples were sized on to minus 100- plus 325-mesh, individually mixed with precleaned sand and leached in an enclosed percolation column. Each mineral was leached in stages to achieve about 90 percent mineral dissolution. The chlorine leaching solutions were produced by reacting sodium hypochlorite with hydrochloric acid within the closed system. The study showed that when the mineral dissolution was complete, the reaction products (copper, iron, and sulfur) were in their highest oxidation states and a stoichiometric amount of chlorine was consumed. Although elemental sulfur formed as an intermediate product, it was oxidized to sulfate during the leach.

Jan 1, 1973

By V. F. Parry, W. S. Landers

"INTRODUCTION The primary object of this investigation was to determine changes in physical and chemical properties of subbituminous lump coal while in storage for 8 months in a typical residence and to demonstrate how this fuel may be stored without degradation or spontaneous combustion. The second object of the study was to determine how the stored coal performed in a hand-fired furnace operated under practical conditions.The investigation revealed that if care is exercised in placing sub-bituminous lump coal in a closed bin, no significant slacking or degrada¬tion occurs, no hazards arise, and over-all indicated efficiencies of about 65 to 69 percent can be obtained under practical,firing conditions that the average home owner can meet.Owing to the war emergency, much attention is being given to the proper storage of coal, and campaigns are being conducted to increase the quantity of coal being stored to relieve transportation and production overloads. Ordinarily, coal dealers do not recommend storage of subbituminous coal in homes owing to deterioration of the coal and to possible hazards from spontaneous combustion. This practice has grown from some troubles that have been experienced, which can be traced to improper preparation, improper bins, and poor technique in placing coal in a bin. There is no good reason why subbiturninous lump coal cannot be stored safely in homes."

Jun 1, 1944

By E. J. Matson

From February until July 1943 the Bureau of Mines conducted an exploration project at the Majuba Hill mine to determine tonnage aria grade of the copper and tin ore and to search for extension of the mineralization. The work comprised sampling, long-hole drilling, underground excavation, and ore-dressing test.

Jan 1, 1948

By Wesley A. Grosh

The Vest nickel prospect, in Floyd County, Va., was discovered about 25 years ago. Limited exploration of the deposit had indicated some appreciable nickel mineralization in the sulfide ore. The property was examined on March 9, 1943, by an engineer of the Bureau of Mines in company with C. W. Vest, owner of the property. A limited exploration program was recommended. Two holes totaling 320 feet were diamond-drilled in January 1944. Drilling indicated the sulfides are sparsely disseminated. The only nickel values of interest were at the old prospect shaft.

Jan 1, 1949

By C. J. Chindgren

Two air classification systems were built and tested as separatory devices for recovering the nonferrous metal values from shredded automotive nonmagnetic reject scrap. A horizontal air system with a capacity up to 16 tons per hour was used to obtain preliminary separations, and a smaller capacity vertical system was used as a cleaning device. Shredded automobile reject material containing aluminum, copper, and zinc values of about $55 per ton were air-classified in the horizontal elutriator. Ninety-six percent of the metal was recovered in a 74-percent metal concentrate. Tandem operation of both classifiers recovered 92 percent of the metal in an 80-percent concentrate while rejecting 87 percent of the nonmetallics. Heavy media separation of the air-classified concentrate produced an overall recovery of 91 percent of the metal in the form of a 99-percent metal concentrate.

Jan 1, 1971

By John Durkin, Roy J. Greenfield

This report discusses the configuration and system deployment for the postdisaster surface seismic system for detecting and locating trapped miners. It analyzes the results of 15 field tests to define a signal model, background noise levels, and subarray performance. A waveform modeling procedure is described and compared with observed waveforms. The resulting similarity indicates that the major factors affecting the signal amplitude, waveform, and spectral character are understood. A model is presented which gives the signal amplitude as a function of source type, source depth, and horizontal off- set between source and receiver. Using this model a curve is presented which gives the range at which a signal will be detected for different signal and noise levels. Finally, and most important relative to the mission of the sys- tem, the ability of the system to detect signals on one or more subarrays is put into a probabilistic framework. For a strong source it is almost certain that a subarray directly over the source will detect the signal. After signal processing, it is highly likely that signals will he detected on sufficient subarrays to locate the trapped miner. Location errors have been found to be less than 100 ft in the majority of cases. Techniques have been used that can reduce the location errors to this level even when soil layer variation between subarrays is severe.

Jan 1, 1981

By A. H. Warner, G. A. Morrison

"INTRODUCTION The brown-iron ores of the Western Highland Rim of Tennessee extend north and south across the State for 115 miles. Many prospects of iron ore are known in this area.The district is credited with an output of 8 million tons of washed ore prior to 1930. Records on past shipments of ore indicates that the grade was probably 45 to 50 percent iron, 0,7 to 1.25 percent phosphorus, and 10 to 21 percent insoluble.As part of a survey of the iron resources of the Appalachian area, the Bureau of Manes began exploration .of the Churchwell and Robinette properties April 16, 1945, and continued until July 25, 1945, during which time 122 feet of test pits were sunk and 667 feet of churn drilling was completedPROPERTY AND ACCESSThe Churchweil property and that part of the Robinette tract north of U. S. Highway 64 are reported to be owned by the heirs of William Millsaps.The Churchwell property is northeast of Waynesboro, the county seat of Wayne County (fig. 1), and is east of Forty-Eight Creek, between Duggar Branch on the north and Little Forty-Eight Creek on the south.The property is reached from Waynesboro by traveling U. S. Highway 64 east 8 miles to Forty-Eight Creek, thence north on a secondary road 2 miles, to where Little Forty-Eight Creek joins it, thence by an old logging road up the hill half a mile to the property.The Robinett tract lies 1 mile southeast of the Churchwell and is reached by traveling east from Waynesboro on U. S. Highway 64 and a distance of 6.7 miles, and then turning left on an old logging road and following the ridge 2 miles to the prospect."

Oct 1, 1946

By J. W. Paul

This circular is one of a series of reports on coal mining methods and cost s which are being prepared by the U. S. Bureau of Mines for the purpose of making available to those interested in the industry a knowledge of the mining methods employed in mines where mechanical and hand loading is practiced and the cost data on the several operations pertaining to the removal of coal from the working faces and its transportation to the tipple for loading into railroad cars. The methods employed are influenced by the natural local conditions with respect to the thickness and character of the coal beds and the overlying strata, the means employed for roof support and its control, and the disadvantages incident to the development of mines in thin coal beds.

Jan 1, 1929

By Bill M. Stewart

To decrease the potential for fine coal waste slurry impoundment failures, the Bureau of Mines investigated a new disposal technique. The fine coal waste slurry is rapidly thickened (i.e., dewatered) and deposited on a slightly sloping surface. To accomplish rapid dewatering, a chemical flocculation system using polymers was developed to treat the fine coal waste slurry stream. The fine solids formed flocs, settled from suspension, and rapidly released excess water. During the last 5 days of the field test, slurry flowing at rates from 498 to 675 gal/min with a specific gravity range of 1.15 to 1.33 was successfully treated and dewatered. During this period, untreated slurry had an average moisture content of 227.4 pct (30.7 wt pct solids). The effectiveness of the dewatering system was determined by monitoring the moisture content of the deposited waste with respect to time. Sixty-five hours after ending the field test the average moisture content was 54.9 pct (64.5 wt pct solids); 68 days after the field test the average moisture content was 28.8 pct (78.0 wt pct solids).

Jan 1, 1986

By Leland A. Yerkes

Refining aluminum from crude aluminum alloys by the subhalide reaction was investigated to develop a method of producing aluminum by means other than electrolysis of its oxide. The best materials and design for the apparatus and also optimum operating conditions, including temperature, pressure, vapor flow rate, and composition of alloy charge were studied. In the subhalide process, aluminum-trihalide vapor reacts with aluminum in the alloy under high temperature and low pressure, forming volatile aluminum monohalide which reverts to aluminum metal and aluminum trihalide on cooling. The only halide used in this investigation was aluminum trichloride. The crude aluminum-silicon alloys used as the principal raw material contained from 21.9 to 36 percent aluminum, and significant quantities of iron and titanium. These alloys were produced by direct electric smelting of clays. Graphite tubing that was heated by an induction coil proved to be satisfactory material for the laboratory reactor chamber, Enclosed in an insulated glass or quartz pipe, the reactor was used in both vertical and horizontal positions with various baffle and tray arrangements for directing the trihalide vapor both over and through the alloy. Aluminum trichloride vapor was generated in the sublimer at one end of the glass pipe, passed into the reactor where contact was made with the crude alloy, and aluminum monochloride gas was formed. When the gaseous mixture of aluminum monochloride and unreacted tri-chloride passed out of the reactor and entered the condenser, the gases were cooled to 900° C. or less, causing the monochloride to disproportionate into aluminum and aluminum trichloride vapor. The aluminum was deposited on the condenser walls while the aluminum trichloride vapor was carried out of the condenser and into the opposite end of the glass pipe where it solidified on the cooled copper coils.

Jan 1, 1961

By J. H. Field

Capital and operating costs have been estimated for removing sulfur dioxide from flue gases of a powerplant of 12,000-kw. capacity by liquid-purification processes, using limestone, ammonia, or sodium sulfite as the reactant. The annnonia and sodium sulfite processes yield end products that may be marketable. Coals containing about 1.5 and 5.0 percent sulfure have been considered. The sulfur dioxide content of the gases to be treated is 0.083 and 0.30 percent, respectively. Estimates have been made for 90-percent removal of the sulfur dioxide from both gases. A third instance has been considered in which 70 percent of the sulfur dioxide is removed from the flue gas of 0.30-percent concentration. The scrubbed gas would contain 0.09 percent sulfur dioxide, which might be within the permissible limit for discharge to the atmosphere in most areas. Although it is unlikely that flue gases with sulfur dioxide concentrations of less than 0.10 percent would require purification, a cost estimate for such a gas is included because an estimate is available for a British plant employing the limestone process at these conditions. Capital investment and operating costs, with no credit for products, are lowest for the limestone process for gases of both concentrations. Crediting the ammonium sulfate and sulfur produced in the ammonia process at their market prices at the end of 1956 of $32 and $28 per ton, respectively, the operating costs of the ammonia process become the lowest for purification of the gas containing 0.30 percent sulfur dioxide. The operating costs of the sodium sulfite process for purifying gas of high sulfur dioxide content approach those of the limestone process when the byproduct sulfur dioxide is credited at $14 per ton. Even if credit for products is allowed for the ammonia and sodium sulfite processes, the operating costs are higher than those of the limestone process for the gas of low sulfur dioxide content. Because of the large quantity of materials that would be produced by removing sulfur dioxide from a relatively small number of plants, credit for products should be allowed with extreme caution.

Jan 1, 1959

By Ted C. Briggs

Twenty-two compressibility runs were made with helium over the temperature range -5° to 80° C and at pressures to 800 atmospheres. A Burnett apparatus was used. Data from the runs were fitted to a fourth degree polynomial equation of state in the pressure and a weighting factor of Pr-3/4 was used. All data for a particular isotherm were treated simultaneously. A temperature function was found to represent the parameters B and C. Compressibility factors determined by this investigation are believed to be accurate to better than 0.05 percent.

Jan 1, 1970

By H. S. Caldwell

Molten zinc, condensed from zinc vapor, was used by the Federal Bureau of Mines to leach aluminum from an aluminum-silicon alloy made by carbothermic reduction of silicious aluminum ores. Zinc requirements were minimized by re-fluxing condensed zinc in a low-pressure, Soxhlet-type distillation unit. The minimum ratio of zinc used to aluminum in the crude alloy was approximately 2:1. When the system pressure was reduced from atmospheric pressure to 100 microns or less, the rate of aluminum extraction increased by a factor of 20. Leaching rates were much higher when the zinc vapor was condensed directly on the crude alloy than when molten zinc was passed over the alloy in the absence of appreciable zinc vapors. Observations indicated higher extraction efficiencies from crude alloys containing greater amounts of iron. Complete extraction was obtained with negligible loss of zinc. Assuming complete removal of zinc, the aluminum products will contain 1 to 6 percent silicon and about 0.5 percent iron plus titanium. The leached crude-alloy residue is a highly friable spongelike material containing about 80 percent silicon, several percent iron and titanium, with the remainder aluminum. This extraction method has been patented (Patent 2,810,637) and assigned to the Government. Research and development investigations are continuing at the College Park Metallurgy Research Center.

Jan 1, 1961

By K. C. Dean

During investigation of the occurrence of manganese deposits in the western United States, examining engineers of the Bureau of Mines collected samples from several properties in Montana. Extensive laboratory tests were made to determine the amenability of these ores to standard ore-dressing methods of concentration to produce marketable-grade products. The Tzarena claim, one of the properties sampled, is on the western end of the Rama or Black Chief vein in the city of Butte, Silver Bow County, Mont., on the southwestern periphery of the mining district. The Black Chief 'WAR system contains one of the largest and most extensive known rhodochrosite deposits in the world. Test work was conducted on two samples of Tzarena ore. Sample 1 is representative of a vain 5 feet wide on the 150-foot level of the Tzarena shaft. Sample 2 is representative of a vein 8 feet wide in the 100-foot level of the shaft. The Minnie Jane mine, 1/2 mile northwest of the Tzarena claim, contains ore similar in mineralogical composition to Tzarena ore but differing materially in manganese content and to some extent in physical characteristics. Ore-dressing investigations were made on three samples of Minnie Jane ore. Sample 1 represented stock-piled ore, sample 2 represented ore from Minnie Jane mine having a considerable sulfide content, and sample 3 represented low-grade ore.

Jan 1, 1951

By Peter H. Toepfer

This report presents the factual data obtained by the Bureau of Mines during diamond-drilling investigation of the Sunset copper deposit in the Index mining district, Snohomish County, Wash. The Sunset mine, first produced copper ore in 1902, but its main period of activity was from 1923 through 1930, The mine has produced 263,500 tons of ore, from which 1,500 ounces of gold, 156,000 ounces of silver, and 12,912,000 bounds of copper-were recovered. The mine has, been idle since 1946

Jan 1, 1953

By W. C. Smith

This Bureau of Mines report discusses how pull-test data can help establish polyester resin column length criteria for roof bolts in evaporite minerals. The study evaluates the effectiveness of partial to full columns of resin in anchoring 4-ft, No.6, grade 40 rebar roof bolts in potash, salt, trona, gypsum, and borate mine roofs. Pull tests were performed on over 600 roof bolts in 11 evaporite mines. Column lengths ranging from 6 to 48 in (fully grouted) were evaluated for each test site. In general, comparative results among all test sites indicate that pull-out loads in excess of 10 tons (force) were attained with resin-grouted bolts having 13 to 75 pet less than a full column of polyester resin. Ten tons (force) of load-carrying capability compared favorably, in terms of strength, with the calculated yield strength of the rebar used in the tests, which was 8.8 tons (force). The site-specific nature of each test site, due to the unique combinations of geology, mine-induced stresses, and other unknown parameters, prevented the establishment of valid generic column-length criteria. For these reasons, data to evaluate resin-column-length effectiveness are best obtained on a mine-specific basis.

Jan 1, 1987

By E. J. Lintner

This paper is one of a series being prepared by the United States Bureau of Mines describing clay mining, crushing and grinding methods, and costs at various clay-mining operations throughout the United States. These papers are designed to disseminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. Although the publication of total production costs might not be advisable in some instances, yet a knowledge of operating costs is essential to the technical discussion and study of the methods employed. The attention of the reader is specifically called to-this distinction between total and operating costs in order that no misunderstanding of the cost tabulations shall ensue. The following report deals specifically with the methods employed by the Dennison Sewer Pipe Co., Dennison, Tuscarawas County, Ohio.

Jan 1, 1936

By Vernon F. Swanson

Several laboratory flotation tests were conducted by the Bureau of Mines on a sample of unweathered diorite from the B. F. Camden property, Amherst County, Va. Results showed that an ilmenite concentrate analyzing 45.5 percent Ti02 (titania), 0.07 percent P205 (phosphorus pentoxide), and 2.21 percent Si02 (silicon dioxide) could be produced from a feed containing 7.72 percent Ti02 and 3.94 percent P205. Ti02 recovery in the concentrate was 47.6 percent in a batch test. The weathered saprolite material overlying the diorite required scrubbing and desliming to remove argillaceous material and preliminary flotation of apatite followed by flotation of ilmenite. The resulting concentrate analyzed 47.3 percent Ti02, 0.19 percent P205, and 0.99 percent Si02 from a starting feed of 8.99 percent Ti02 and 3.37 percent P205; TiO2 recovery was 54.5 percent.

Jan 1, 1963