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By V. E. Edlund

As part of its efforts to devise new and improved methods for recovering lithium from unconventional resources , the Bureau of Mines investigated a lime -gypsum- roast , water- leach technique for processing lithiumenriched ( 0.01-0.68 pct Li ) clays . This report presents the results of a study of the technical feasibility of extracting lithium from raw material representative of clay beds associated with the McDermitt Caldera complex in Nevada and Oregon . prepared from water used Pellets suitable for bench-scale roasting studies were mixtures of minus 200 -mesh clay , limestone , and gypsum , with as the pelletizing agent . Roasting pelletized charges at 900 ° to 1,000° C temperatures for 1- to 4-h periods produced calcines that leached readily , yielding water - soluble lithium sulfate ( Li₂SO4 ) . A 5-3-3 ( weight ratio ) mix of clay , limestone , and gypsum produced calcines with the best leaching characteristics . More than 91 pct of the contained lithium was extracted from pelletized mix batches roasted in covered refractory boats . Lithium recovery decreased to about 87 pct when the mix was roasted under dynamic conditions in a gas - fired rotary furnace . A reaction mechanism was postulated which indicated that dilution and loss of SO2 and oxygen in the combustion exhaust adversely affected the leachability of the dynamically roasted calcine .

Jan 1, 1983

By Yael Miron

The presence of pyrite (FeS2) in coal can cause or contribute to several problems for the coal mining industry. These problems, which include spontaneous combustion, roof falls, floor heave, and accidental explosions in coal surface mining when ammonium nitrate fuel oil (ANFO) explosives are used, result from pyrite oxidation. Pyrite oxidizes exothermically in the presence of air and moisture to form a large variety of products, including hydrated ferrous and ferric sulfates, and sulfuric acid. Some of the products are reactive chemicals and strong oxidants. The volume of many of these oxidation products exceeds the original volume of the pyrite; as a result, the adjacent coal disintegrates and its surface increases, rendering it more susceptible to oxidation. The heat from pyrite oxidation raises the temperature of the adjacent coal, accelerating the oxidation and self-heating rates of the coal. These combined chemical, physical, and thermal effects are the cause of the aforementioned problems. When ANFO is used in surface coal mines and contacts ferrous sulfate, a highly exothermic reaction ensiles. Additional hazards are fires or explosions caused by the frictional ignition of methane when the pyrite in the coal is struck by a cutting bit during mining.

Jan 1, 1994

Consumption and intensity of use trends for 12 metals, by industrial end use, were estimated for 1972 through 1982 by the Bureau of Mines and U.S. Department of Commerce. The trends were then forecast through 1993 using standard statistical methods. The intensity of use measure selected is the quantity of metal consumed per constant dollar output of a specific industrial sector. The metals studied were aluminum, chromium, cobalt, copper, lead, manganese, nickel, the platinum-group metals, tin, titanium, tungsten, and zinc. Average annual growth rates for the following 4 of the 12 metals increased from 1972 to 1982 as follows: aluminum, 1.00%; platinum-group metals (consisting of platinum, palladium, and iridium), 8.83%; titanium, 7.82%; and tungsten, 6.09%. Consumption for the remaining eight metals decreased at average annual rates ranging from 0.58% (copper) to 5.37% (manganese).

Jan 1, 1986

By J. B. Zadra, J. M. Gomes, Don H. Baker

Electrolytic deposition at 1,000 ° C in an electrolyte essentially consisting of 7 parts sodium pyrophosphate , 2 parts sodium chloride , and 1 part sodium tetraborate yielded tungsten of 99.9 percent purity . Scheelite concentrates containing 25 to 73 percent WO, and varying quantities of iron , lime , and silica were used as feed materials for the electrolysis . The metal contained less than 0.01 weight - percent each of iron , calcium , silicon , aluminum , carbon , and oxygen . Modification of the electrolyte permitted deposition of equal - quality metal from scheelite concentrates containing higher quantities of iron , calcium , and silica . The electrolytic separation of molybdenum and tungsten was accomplished by minor variations in the operating procedures .

Jan 1, 1964

By Richard F. Hewlett

Numerous populations of assays have been simulated for a range of assay values representative of low-grade mineral deposits to facilitate the study of problems encountered in evaluating these deposits. Analysis of these simulated populations of assays (obtained by using statistical probability models for the simulation) makes possible the quantification of the effects of (1) various composite assay intervals, (2) ore reserve computational methods, (3) uneven assay intervals, and (4) various cutoff grades on both the precision and the accuracy of the estimated average grade and tonnage of ore.

Jan 1, 1964

By Robert E. Barieau

General expressions for evaluating various thermodynamic properties applicable to the van der Waals equation of state have been derived. These formulas were subsequently used to evaluate various thermodynamic functions in the two-phase region. The results indicate that, for a van der Waals fluid, there is a finite discontinuity in the second derivative of the vapor pressure curve, in the second derivative of the chemical potential or Gibbs free energy at the critical point, and in the heat capacity at constant volume measured at the critical density. Numerical values are tabulated and graphs are presented for all functions calculated.

Jan 1, 1967

By Arne Landsberg

A study of the chlorination kinetics of germanium, silicon, iron, tungsten, molybdenum, columbium, and tantalum has been made to determine the effects of temperature, chlorine concentration, geometric surface area and gamma radiation. The reaction products were volatile at the temperatures used this making it possible to follow the reaction rates by weight loss of the solid. Chlorination rates of germanium, silicon, and iron were found to be directly proportional to chlorine concentration while the rates for tungsten, molybdenum, columbium, and tantalum were proportional to the 0.5 to 0.6 power of chlorine concentration. A good correlation of reaction rate and geometric surface areas was not obtained because the true surface area of the samples could not be measured. Intense gamma radiation had no effect on reaction rates. The Arrhenius activation energies determined over the temperatures used are as follows: Germanium, 27 kcal/mole (233°-241° C); silicon 33 kcaL/mole (375°-517° C); iron, cold rolled, 20 kcal/mGle (259°-325° C) annealed, 21 kcal/mole (293°-337° C); tungsten, 43 kcal/mole (617-776° C); molybdenum, 37 kcal/mole (445°-4910 C); columbium) 34 kcal/mole (229°?255° C); and tantalum, 29 kcal/mole (370°-449° C).

Jan 1, 1965

By Clarence O. Babcock

In this report, the Bureau of Mines presents a method for reducing the complexity of designing room-and-pillar mining systems by treating them as anisotropic soft inclusions in the surrounding ore or host rock. Theoretical models were derived for the calculation of the effective Young's moduli for these systems. The predicted behavior of the plate-type elements used in these models agreed well with test results from 21 plates each with 49 holes spaced on a 7 X 7 Cartesian grid. The plates behaved as anisotropic solids, the effective Young's moduli of which could be predicted from the scaled hole size and spacing. Actual hole shape was insignificant. The effective Young's moduli for simple mining systems are calculated in sample problems. This approach should provide information about field stress in the mining region and the stress distribution in the surrounding ore or host rock when the actual mining configuration is replaced by an anisotropic inclusion in a finite element analysis. The field stress within the inclusion can then be applied to the actual opening shape to determine the stress distribution within the mining region.

Jan 1, 1970

By D. I. Bleiwas

The Bureau of Mines determined demonstrated tin resources and costs associated with tin production in order to evaluate the potential for tin production from 18 market economy countries (MEC's). Data were collected from tin producers, in most cases during on-site visits. The analyses evaluated the relative economic and resource position of 146 mines, deposits, or regions in January 1984 dollars. The demonstrated resource of recoverable tin within the nations studied is approximately 2.8 million metric tons (mt). Of this total, over 73 pct is recoverable from the Southeast Asian countries of Malaysia, Thailand, and Indonesia, which in 1983 accounted for almost 60 pct of the world's tin production. Brazil has joined the Southeast Asian countries as a major low-cost, high-volume supplier of tin and is likely to continue to expand its production. Given the 1984 market structure, over 60 pct of the tin in demonstrated resources was economically recoverable. Historically, the International Tin Council (ITC) has helped maintain relatively stable tin prices through a buffer stock and sales quotas. In late 1985, exhaustion of buffer stock funds led to suspension of tin trading on the world's major tin metal exchanges.

Jan 1, 1986

By C. H. Riggs

This report describes the development, oil recovery, and potentialities of productive formations in the Hall-Gurney field, Russell County, Kans. It is presented as part of a general program to aid and promote increased recovery from petroleum reservoirs. The report is based on studies of well logs, drill cuttings, and oil-and water-production histories of individual wells and leases. The geological interpretations follow closely those in published literature with only slight local modifications. Oil and water analyses, made at a Bureau of Mines research center, were supplemented by many analyses obtained from oil-producing and service companies. The Hall-Gurney field, in south central Russell County, Kans., (fig. 1) was discovered in 1931 but was not developed extensively until 1941. By 1960 the rate of oil production from the field had declined to the extent that many wells were abandoned. In some areas natural productive forces have effected good recovery. However, in other areas inefficient waterflooding, both natural and accidental, has adversely affected recovery potentialities.

Jan 1, 1963

By John M. Gomes

Two molten salt systems were evaluated as electrolytes for the repetitive recovery of tungsten from tungsten oxide (W03) made by calcining commercial-grade ammonium paratungstate. Using a sodium chloride-sodium fluoride-potassium aluminum tetrafluoride electrolyte at 800° C, 1 pound of 99.8 percent tungsten was recovered for each 2.7 kilowatt-hours of energy consumed. The metal contained 1,100 ppm carbon, was in dendritic masses of spherical grains, and had an apparent bulk density of 5.41 g/cm3. T ngsten of 99.9 percent purity was won from a sodium pyrophosphate-sodium tetraborate-sodium chloride electrolyte at 1,000° C; 6.0 kilowatt-hours of energy was consumed for each pound of metal recovered. The metal contained 120 ppm carbon, was in dendritic masses of hexagonal acicular crystals, and had an apparent bulk density of 7.25 g/cm . Each metallic impurity--aluminum, calcium, copper, iron, nickel, and silicon--in the two tungsten products was 16 ppm or less.

Jan 1, 1966

By Jon C. Volkwein

Advances in mining technology have enabled deeper seams of coal to be mined from the surface. Highwall mining is frequently used to mine areas at the perimeters of a surface mine when removal of the overburden becomes uneconomical or threatens environmentally sensitive surface features. At the same time, advances in materials and technology have enabled highwall mining of coal that create blind headings over 300 meters in length. Deeper surface mining and deeper highwall penetration depths have lead to more frequent encounters with methane gas. While this coal is remotely mined from the surface, underground ignitions of methane have propagated to the surface and injured miners. Methods described in this paper show how this hazard can be correctly monitored and controlled for auger type highwall mining machines. Research indicates that small quantities of gas liberated during mining migrate to the face, creating higher gas concentrations than would otherwise be expected. Using the same principles that cause the gas to migrate to the face, researchers have shown that inert gas introduced at the collar of the hole can inert the entire hole, thus ensuring safe conditions for mining.

By Roy L. Grant

The Bureau of Mines investigated the up-and-down method with factorial designs to determine if shorter, and therefore less costly, trial sequences could be used. Although sequences of 50 trials are usually recommended, sequences of 20 trials were arbitrarily chosen for the experiments with permissible coal mine explosives described in this report. These explosives were fired from a cannon pointed into a flammable natural gas-air atmosphere at the Bureau of Mines Explosives Research Center gallery to ascertain their safety properties. The investigation demonstrated that the shorter sequences led to useful conclusions with a reduction in cost of the experimental program.

Jan 1, 1967

"Qatar, crude petroleum, production, annualdata MY 1949-51Quality mine, Ark., coal, carbonizing properties TP 667washabilty study RI 496N. Dak., lignite, grindabilty as function ofmoisture, tests, results RI 5167"

Jan 1, 1960

By Roy T. Sorensen

The Bureau of Mines has investigated the recovery of cell-grade alu-mina by RCI leaching of calcined kaolin in the alumina miniplant at its Boulder City (NV) Engineering Laboratory. Classification and thickening were used for separating aluminum chloride leach liquor from the siliceous residue generated in the acid leaching step of the clay-HCI process. Coarse solids were classified from fines at 115 mesh and countercurrently washed in three additional spiral classifiers. Fines were treated in a conventional five-thickener, countercurrent decantation circuit. When this method was applied to the solids-liquid separation of slurry from RCI leaching of minus lO-mesh calcined kaolin, 75 pct of the residue reported as classifier sands and 25 pct as thickener underflow. Predicted individual classifier and thickener area requirements were 6 and 25 ft2/tpd, respectively. Total thickener circuit flocculant requirement was 2.4 lb/ton solids. Aluminum chloride pregnant liquor was produced that analyzed 8.4 pct A1203 and contained more than 97 pct of the alumina in the liquid phase of the slurry. Bench-scale settling tests were used to correlate fines content of leach residue to thickener area and flocculant requirements.

Jan 1, 1983

By D. F. Walsh

A study of damping capacity was made on a number of magnesium-base alloys, commercial types and experimental compositions. Hardness and tensile properties were determined, and the microstructure of each alloy was examined. Alloys of low yield strength, in general, possessed high damping ability. A correlation was established between damping capacity and composition.

Jan 1, 1962

In the interest of safety in metal mining, the Bureau of Mines recommends: That underground metal mines be equipped with a main fan in a fireproof housing, located preferably on the surface. The fan installation should be designed to ventilate the mine adequately throughout and to permit prompt reversal of direction of air flow. Many metal mines depend for ventilation upon natural flow of air, assisted by the exhaust from pneumatic drills and by compressed air blown into the workings. Others also ventilate separate headings or sections with fans and blowers. Relatively few have o mechanical ventilating system that controls the coursing of air throughout the mine.

Jan 1, 1939

In the interest of safety ii: coal mining, the Bureau of Mines recommends: That all active underground coal mines, whether working or idle, have one or more fans in continuous operation. The capacity and installation shall be such that the entire mine workings are adequately ventilated at all times. Main fairs shall be located on the surface in fireproof housing offset from the line of any mine opening. The housing shall be provided with ample pressure-relief doors or other devices easily opened by the force of an explosion. The installation shall permit prompt reversal of air flow. For mines that liberate gas, the fan shall have at least two independent sources of rower immediately applicable. Ventilation of underground workings in coal mines is needed whether or not explosive gas is present. Natural ventilation is unreliable and often uncontrollable. Main fans should be on the surface; if they are in the mine, fire or explosion may make access difficult or dangerous and render the installation inoperative.

Jan 1, 1939

By Michael J. Brnich

During the past 15 years the number of reportable mine fires has declined. A decline in the number of reportable fires is a gross indicator that allows experts to say something about the underground coal industry generally: There has been some improvement in overall mine fire preparedness. However, such an indicator is less reliable as a predictor of readiness at any particular operation. An indication of fire fighting preparedness would have to be assessed from evidence gathered at the mine site. In other words, there are two levels from which to view the problem. On a general level, there has been significant improvement in the industry's fire response capabilities over the past two decades. Specifically, however, little data has been gathered on a site-by-site basis to determine what improvements might be made on a local level. These improvements would move beyond regulatory compliance. It is expected that this manuscript, based on work conducted at an underground coal mine in the western United States, will help to focus attention on some central concerns involving this critical issue.

Jan 1, 2006

By William J. Campbell

This study was a part of two programs: The first, to develop and evaluate high-temperature refractories; the second, to investigate reaction-rate kinetics and phase equilibria in the sinter step of the lime-soda process for the recovery of alumina. High-temperature X-ray diffractometer techniques are to be used extensively in both programs. This paper summarizes developments in the field of high-temperature X-ray diffractometers through 1959, evaluates various furnace designs, and describes briefly the X-ray diffraction facilities of the Federal Bureau of Mines. A more detailed description of the equipment and its calibration is planned in a future paper on thermal expansion and phase inversion of rare-earth oxides.

Jan 1, 1961