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By R. C. Anderberg, F. J. Caervenyak, F. J. Frattali, H. J. Kandiner, R. A. Brown

"INTRODUCTION Considerable interest was shown .prior to and during World War II in the winning of metallurgical-grade alumina from anorthosite, kaolin, siliceous bauxites, diasporic clays, and other aluminum-bearing ores. Laboratory and pilot-plant investigations were made on many of these ores by the Bureau of Mines, and a series of reports on them is being prepared. This report covers the tests made on the application of the lime-soda-sinter process to anorthosite, which is a mixture of albite, NaAlS1308, and anorthite, CaAl2Si208. Extensive deposits of anorthosite occur in the Laramie Range in Wyoming and extend into Colorado; other deposits are found in New York, with outcroppings appearing in Vermont, Maine, and Labrador.Anorthosito can not be treated by the Bayer process for the production of metallurgical-grade alumina, because excessive losses of soda and alumina occur from the formation of sodium-aluminum silicate due to the large amount (50 percent) of silica in the ore.RESULTS OF INVESTIGATIONSSmall-scale laboratory tests supplemented by pilot-plant runs have demonstrated that the alunina and soda occurring in the Wyoming anorthosite from the Laramie Range can be extracted and recovered satisfactorily by the lime-soda process. It has been shown that liquors containing approximately 95 gram of A1203 per liter can be consistently produced at Na20:A1203 ratios from 1.75 to 2.27, and that these liquors can readily be desilicated and carbonated to yield high-grade alumina trihydrate of quality comparable to that essential for cell-grade alumina. The optimum results were obtained with Na20:A1203 mol ratio of 1.03 and Ca0:Si02 ratio of 2.14 in the sinter when calcined at an average temperature of 2,444ºF. for 25 minutes."

Nov 1, 1947

By D. W. Frommer, M. M. Fine

"INTRODUCTION Laboratory mineral-dressing investigations covered by this report show that ores from Montgomery County, Ark., and Morgan County, Mo., are potential sources of barite and zinc. Fine grinding and froth flotation yielded drilling-grade barite from the former and chemical-grade barite and zinc concentrates from the latter.Samples from these deposits were subjected to a laboratory investigation to develop an economic and feasible treatment. The Arkansas ore, submitted by the Husky Refining Co., consisted of an intimate mixture of the economic mineral and quartz. Fine grinding and fatty acid flotation were utilized to effect a good recovery of a drilling-grade product. The other was a zinc-barite ore submitted by the Rocky Ford Mining Co., Stover, Mo. There was no problem in the recovery of zinc (most of which occurred as sphalerite), but the recovery of barite by flotation was complicated by the presence of gangue carbonates. Ultimately, an excellent recovery of barite was achieved with a relatively new type of flotation promoter, petroleum sulfonate.In recent years, barite has become one of the major industrial minerals as an essential ingredient in heavy drilling fluids, pigments, and chemicals. New sources of this important commodity are always interesting; thus, it is the purpose of this report to present information that may permit commercial exploitation of two deposits not in production."

May 1, 1952

By Raymond B. Ladoo

Talc mining ·in the state of New York was first started about 1876, but important production did not start until 1880, when about 4,000 tons were shipped, In 1883 the production was about 6,000 tons valued at $75,000, or an average of $12.50 per ton, From this date the production gradually inc~eased to a peak of 93,236 tons in 1916, valued at $961,510 or about $10,30 per ton, In 1918 the production declined to 71,167 tons valued at $902,100, or about $12,70 per ton. For ma.ey years New York ,-Jas the largest producer in the United states, but in 1917 and 1918 its output was surpassed by Vennont in tonnage thou[;h not in value. In June, 1920, there were three companies producing talc in the Gouverneur district, st. La,1Tence Co'Ul'lty, and one near Natural Bridge.

Oct 1, 1920

By L. C. IlsLey

"According to accident statistics, issued from time to time by the Department of the Interior, Bureau of Mines covering fatalities in coal mines, between the years 1870 and 1921 there were 4,897 deaths caused by explosives. The legislatures and safety commissions of the various mining States have Elected and formulated many excellent regulations in regard to the handling and use of explosives in an endeavor to keep this class of accidents as low as possible. An analysis or comparison of the explosive, regulations issued by over thirty States would make a very long paper, however, by subdividing according to phases and issuing several papers it is believed that the material will be more readily available. The first phase was treated in Serial No. 2405 of the Bureau of Mines (""State and Federal Electrical Shot-Firing Regulations,"" issued in October 1922) which gave a compilation of such regulations as apply strictly to electric shot-firing. The second phase under consideration is ""Who may set off blasts in coal mines.""In some States, the person who does the firing must be an ""authorized shotfirer,"" while in other States he must have proved his ability to do this work, and again in other States he is ""any person."" The present paper covers rules and regulations relating to this phase of shotfiring, and those States having similar regulations have been grouped as follows."

Jun 1, 1923

By K. O. Bennington

The thermodynamic properties of pollucite [(Cs0.650Na0.185Rb0.028)(AlSi2) (05.8630H0.137)?0.19H201 were determined by the Bureau of Mines in collaboration with the Argonne National Laboratory. The standard enthalpy of formation determined by hydrofluoric acid calorimetry is ?Hf°298 = -3,098.52 ±3.63 kJ mol-1. The standard enthalpy of formation from the oxides is ?H298 (from oxides) = -209.50 ±2.38 kJ mol-1. Low-temperature heat capacities were determined by adiabatic calorimetry from 5.0 to 306.1 K. The derived standard entropy is S°298 = 207.24 ±0.43 J mol-1k-1. Enthalpy increments above 300 K were measured by copper-block drop calorimetry from 349 to 674 K. Various experimental data were combined with other data from the literature to calculate the Gibbs energies of formation and equilibrium constants of formation over the temperature range of measurements. Standard enthalpies of formation and Gibbs energies of formation are given as functions of temperature. The Gibbs energy of formation is ?Gf°298 = -2,919.9 W mol-1

Jan 1, 1983

By L. H. Kalenowski

The metal lithium, its alloys, and its salts are becoming Increasingly important as industrial materials. Lithium metal, because of its great affinity for elements, such as nitrogen, hydrogen, oxygen, sulfur, phosphorus, carbon, and silicon, has become important for a wide variety of uses, ranging from purifying helium gas by removing the nitrogen to scavenging molten metals of undesirable impurities. The excellent fluxing properties of lithium salts have found increasing use in such applications as fluxes for welding aluminum and in lower melting ceramic glazes and coatings. Lithium chloride is one of the most hygroscopic salts known and is widely used as a dehumidifying agent. .About 17 lithium minerals are known. Four of these have commercial importance: Amblygonite, lepidolite, zinnwaldite, and spodumene. Spodumene is the most important source of lithium and lithium salts at present, but sizable deposits of amblygonite occur in the pegmatite area of the Black Hills of South Dakota. The size and nature of these deposits preclude the, possibility of, any assurance of an adequate supply of amblygonite for an operation processing only this mineral. Frequently spodumene and amblygonite occur associated in pegmatite minerals. Preliminary investigations indicate that a simultaneous recovery of spodumene and amblygonite can be made by froth flotation. A single process for treating spodumene and amblygonite or mixtures of thorn, would make possible more use of amblygonite as a source of lithium and obviate the separation of spodumene and amblygonite when they occur together.

Jan 1, 1952

By G. R. Hopkins

"The average heat requirement per barrel of crude refined in the United States rose from 579,000 B. t. u. in 1940 to 584,000 B. t. u. in 1941. This marked the second successive year in which there was an apparent loss in fuel efficiency at refineries. This ""loss"" took place despite an increase in crude runs, which used to be an invariable indicator of a lower average.Probably the chief factor in the increased heat requirement in 1941 was the gain in the over-all gasoline yield from 43.1 percent in 1940 to 44.2 percent in 1941. Possibly another important factor was the further use of obsolete equipment to increase throughput.The refiners used more of all kinds of fuel excapt coke in 1941 than in 1940. However, the only fuels which increased materially in relative importance were refinery gas, which contributed 51.6 percent of the total heat units in 1941 compared with 50.7 percent in 1940, and natural gas, the share of which rose from 17.1 percent in 1940 to 18.0 percent in 1941. The changes in the percentages for the other fuels were as follows: Oil decreased from 25.7 to 24.1 percent; acid sludge fell from 2.7 to 2.5; coal remained at 3.4 percent; and coke (including steam) fell from 0.5 to 0.4 percent.New records for fuel efficiency were set in all three of the districts east of the Mississippi, namely, East Coast, Appalachian, and Indiana, Illi¬nois, etc. All the ether districts reported higher average fuel requirements in 1941, except the Louisiana Gulf and Arkansas-Louisiana inland.Since the year of the first statistics, the refiners have steadily increased their purchases of electricity. In 1941 total purchases were 1,862,996,000 kilowatt-hours, or 11 percent more than in 1940."

Apr 1, 1943

By T. M. Ruff

The U.S. Bureau of Mines has developed a portable, inexpensive teleoperation system for mobile hard-rock mining equipment. The system was tested on a compact loader-trammer in a simulated stope. The teleoperation system includes radio remote control and computer-assisted navigation. A recent enhancement includes video cameras mounted on the machine to provide visual information to the operator. This system allows the operator to remain in a safe location while operating the machine from a distance, thus increasing both operator safety and mining productivity.

Jan 1, 2010

By Perry G. Cotter

As a portion of a general program for the synthesis of hard materials, a method was sought by which the hardness and density of tungsten carbide (WC)-cobalt compacts could be increased. It was demonstrated by Cotter that these improvements in quality could be made by employing an electric-resistance sintering process in which heat and pressure are applied simultaneously to presintered compacts composed of powdered tungsten carbide and cobalt. This conclusion was based on tests of material prepared by Cotter on welding equipment in use at the U. S. Naval Engineering Experiment Station, Annapolis, Md., and at Rensselaer Polytechnic Institute, Troy, N. Y. Rockwell-hardness tests made at Norris and core-drilling tests made at the Mount Weather Station of the Bureau of Mines indicated that, for some purposes, carbide material made by this process might be superior to the chemically analogous commercial products prepared by ordinary sintering methods. A program to develop optimum conditions for the electric-resistance sintering of tungsten carbide-cobalt compacts was initiated. The program was followed by a systematic evaluation of the hardness and density of compacts prepared by this method along with a series of carbide compacts furnished by various manufacturers. This paper presents a description of the electric-resistance sintering of tungsten carbide-cobalt compacts and the results of comparative physical tests.

Jan 1, 1955

By Alan G. Mayton

The Bureau of Mines conducted a study to (1) determine from laboratory tests the feasibility of a photographic method for determining reflec-tances that may be applied to measuring in-mine mineral reflectances and (2) formulate a procedure for collecting and analyzing the data. The method uses a 35-mm camera with automatic flash and a gray-scale re-flectance standard to collect on film the reflectivity data in under-ground mineral mines. After the film is processed, the data on the photographic prints are analyzed in the laboratory with a photometer. Test results show the photographic method can provide values of reflec-tance to within ±5 pet of full scale (full scale = 100 pet). The method's usefulness for determining reflectivity values, within similar limits of absolute percent error at the lower end of the scale, however, has not been completely resolved by the study and consequently warrants further investigation. The method offers an acceptable means for collecting and analyzing reflectivity data for reflectivities at the higher end of the scale, i.e., 50 pet or above; it should be used with caution when reflectivity values are below 50 pet. Four films were evaluated; all gave relatively satisfactory results.

Jan 1, 1987

By J. D. Spagnola

The Bureau of Mines conducted research to obtain comparative data on the extent of reduction of galena and sphalerite with molecular hydrogen and with hydrogen from the thermal cracking of ammonia and methane at various time intervals. Galena reductions of 95 to 99 percent were obtained with H2 and with decomposed NH3 while reductions of 70 to 80 percent were obtained with cracked CH4? Sphalerite reductions of 99 percent were obtained at 1,000° C with Hz and with decomposed NBs; however, complete volatilization of the free zinc from the remaining concentrate and the subsequent recombination of zinc and sulfur vapors resulted. A promoted iron catalyst brought about a decrease of 100° C in the temperature required for complete decomposition of ammonia. It was found that H2S retards NB3 decomposition and that nitrogen retards the reduction of galena by H2? A mixture of N2 and He in about the same ratio as that obtained by the thermal cracking of NBs gave about 15 percent less reduction of galena than was obtained with decomposed NB3; this indicates that a portion of the hydrogen obtained by NBs decomposition is in an active form.

Jan 1, 1965

By W. W. Agey

The Calico silver-barite deposits near Barstow, Calif., are a potentially important resource. Exploration performed by two major mining companies out-lined large tonnages of ore that assayed at 2 to 3 ounces of silver per ton and 7 to 15 percent barite. Laboratory beneficiation work was done by the Bureau of Mines on four samples to develop methods for recovering the silver and/or barite. Cyanidation recovered from 47 to 60 percent of the silver from ore ground to approximately 100 percent minus 325 mesh. Salt roasting minus 10-mesh material, followed by regrinding and cyanidation, recovered 75 to 85 percent of the silver. From 75 to 90 percent of the barite was recovered in a plus 92-percent barite product from either the natural ore or from cyanidation residues. Salt roasting before cyanidation precluded recovery of the high-grade barite concentrate from the leach tails.

Jan 1, 1973

By Van E. Shaw

Bastnaesite is a natural rare-earth fluorcarbonate of the cerium group that affords an abundant and high-grade source of the lighter rare-earth elements. A simple and efficient method has been developed by the Bureau of Mines for extracting rare-earth compounds from this mineral. Digesting of a flotation concentrate with sulfuric acid converts the rare-earth compounds from fluorcarbonates to sulfates. Action of the acid releases gaseous com-pounds of fluorine and silicon, leaving the sulfated material free of these elements; carbon dioxide from carbonate decomposition is eliminated at the same time. Calcining the sulfated material at 1,200° F. renders the gangue constituents insoluble, whereas the rare-earth sulfates are left in water-soluble form. Leaching with water yields a solution of pure rare-earth sulfates. Bastnaesite could become prominent as a source of cerium-group rare-earth elements. It is rich in the light rare-earth elements and comparatively easy to process; reserves of the mineral are extensive enough to supply a greatly expanded market for many years.

Jan 1, 1959

By A. Gene Collins

Some of the geochemical relationships that exist between subsurface fluids and the associated geologic strata in petroleum producing areas of Louisiana have been determined. Samples of petroleum-associated water were obtained from 126 wells in Louisiana that produced from sediments of three geologic ages: Tertiary, Cretaceous, and Jurassic. The samples were trans-ported to a central laboratory for analysis of chemical composition, using standard methods, to determine if the compositions varied with the geologic strata of their source and, if so, why. The dissolved constituents were com-pared with those of a brine that was concentrated by evaporation. The concentrations of bromide, calcium, and strontium were useful in distinguishing the brines produced from sediments of a late age from those of an earlier age. The concentration ratios of Mg' (total equivalent magnesium) and bromide indicated that dolomitization probably had occurred and altered the composition of the brines. A principal-components analysis of the data indicated an inverse relationship between depth and concentrations of bromide, strontium, calcium, and lithium.

Jan 1, 1970

By C. R. Stephan, N. B. Greninger, S. J. Luzik

The U.S. Bureau of Mines conducted explosion tests on various full-scale cementitious bulkheads used in abandoned mine areas to evaluate the ability of the bulkheads to withstand gas explosion over-pressures of 20 psig. Tests were performed on 120-ft2 solid-concrete-block seals of varying thicknesses and designs. Of the seven solid-concrete-block seals tested, only the standard-type seal, having a 16-in thickness, keyed at the floor and ribs, all joints mortared, wedged at the roof, and a center pilaster, maintained its integrity when subjected to a 20-psig pressure wave. After being subjected to repeated explosions, the standard seal only showed a small hairline crack and had an air leakage of 87 ft3/min at a pressure differential of 1 in H2O. Tests were performed on cementitious foam seals of varying thicknesses and compressive strengths. Explosion tests have shown that 200-psi strength, 4- and 8-ft-thick seals can withstand a 20-psig pressure wave. At a pressure differential of 1 in H20, no air leakage was detected through the 200-psi, 8-ft-thick foam seal.

Jan 1, 1991

By Steven J. Page, John A. Organiscak

Prolonged exposure to airborne respirable coal mine dust is responsible for coal workers' pneumoconi¬osis (CWP): Furthermore, miners who show evidence of higher radiographic categories of simple CWP are at increased risk of developing progressive massive fibro¬sis (PMF). As of 1990, there were nearly 130,000 coal miners in the United States. "' This excludes mines that produce less than 10,000 tons annually and the anthracite coal mines. Estimates indicate that at age 58, an average of 7/1000 U.S. workers and 89/1000 U.K workers will have developed PMF(2-1) Health research studies have iden¬tified that the risk of developing and the severity of CWP arc directly related to (1) the amount of respirable dust exposure and (2) the coal rank.,'- The rank of coal is its stage of formation in the series peat, lignite, sub-bituminous, bituminous, and anthra¬cite (in order of increasing rank). The rank of coal can also be represented by the com¬mercially important characteristics specified by its proximate analysis: fixed carbon, vol¬atile matter, mineral matter, and moisture content.

By N. Grosland, G. Kopp, L. Frey-Law, D. Wilder, M. Contratto, S. Rahmatalla, T. Xia

Heavy equipment manufacturers have made a long-term commitment to minimize operator vibration exposure for comfort, performance, and health reasons. Domestic and international guidelines/standards and EC laws dictate exposure limits based on measurement of vibration at the interface between the seat and the operator’s buttocks using seat-pad accelerometry.1-4 This is historically based on the assumption that the only major source of vibration is transmitted through the seat pan. However, vibration may also be imparted to the head and neck via the steering wheel and/or arm-rest controls and a relatively rigid upper body.5 Unfortunately, little is known regarding the influence of arm position on head and neck motion. The purpose of this study was to investigate relative head and trunk motions during riding simulations of large construction equipment, using three different arm control options. Methods Five typical heavy equipment ride files were “played back” through a man-rated Servo Test 6-degree-of-freedom vibration system. An 8-camera Vicon motion capture system operating at 200 frames per second, recorded the motion of reflective surface markers on 5th, 50th, and 95th percentile right-handed male subjects, using 3 seat and control configurations (steering wheel (SW), floor mounted armrest controls (FM), seat-mounted armrest controls (SM)). Two trials were performed for each ride and seat control combination (each trial: 60 sec of 6-dof and 60 sec of vertical vibration). The relative motions (change in distances) from the marker over the xiphoid process (caudal end of sternum) to markers over each shoulder, each mid-clavicle, the presternal notch, and to each of four markers on a tight band around the head were calculated (12,001 frames, 6-dof motion only). As a rigid body control, distances between markers on the head band were also monitored. The standard deviation (SD) of the 12,001 distances between pairs of markers was normalized by the mean (L) of the associated distances producing: SD/L which was used as a measure of motion. Error assessments were also performed by analyzing the motion between relatively fixed markers (on the headband). A repeated measures analysis of variance was used to evaluate the results. While five ride files were used, only one ride file containing significant lateral acceleration components was analyzed for comparing the effects of two armrest controls versus use of a steering wheel for this part of our study. Results Values of SD/L between the points on the relatively rigid head band were consistently small and similar to each other for all conditions with one exception due to treatment (SM v SW, p=0.0145). SD/L between the markers over the xiphoid process and the presternal notch, another region that should be relatively rigid, were also similar to each other for all conditions. Use of floor-mounted, arm rest controls versus a steering wheel produced a significant increase in the value of SD/L between the xiphoid process and: the right shoulder marker (92%, p=0.0316), the right mid-clavicle marker (47%, p=0.0478), and the right-front marker on the head band (28%, p=0.0182). Use of floor-mounted, arm rest controls versus seat-mounted, arm rest controls

Jan 6, 2006

By W. J. Pena, C. W. Owings

"Generally, the hazard of cool-dust explosions in tipples and cleaning plants is not given the consideration that is given it underground. This lack of consideration is probably due to failure to appreciate the potential hazard. An explosion in a tipple or cleaning plant is basically little or no different from an explosion underground. If bituminous-coal dust is raised into a cloud in the air and comes in contact with arcs from motor brushes, switches, or open flame, the dust is very likely to ignite, and flame will very probably propagate or extend through it if the quantity of dust per unit of air space is sufficient. The open space in a tipple or cleaning plant may reduce the violence of the explosion, but it is not likely to prevent ignition or propagation of flame.The movement of coal through a tipple or cleaning plant naturally puts into suspension a large amount of dust, which finally settles on exposed surfaces. Any disturbance that will put this dust into suspension in a sense enough cloud can result in the dust being ignited by an arc or open flame if one should be present. An explosion of bituminous-coal dust in a tipple or cleaning plant generally can be prevented either by keeping it thoroughly clean or by removing all sources of ignition, or both.The tests at the U.S. Bureau of Mines Experimental mine have shown that the explosibility of coal dust is proportional (other things being equal) to the ratio of the volatile matter to the volatile matter plus the fixed carbon, indicated thus:The volatile ratio for the Pittsburgh coal bed is calculated as follows:Therefore, as the volatile matter decreases the liklihood of ignition decreases; however, coal-dust explosibility depends on other factors also, such as fineness, dryness, and cloud density; and under some conditions other factors also intervene.Proof of the explosibility of coal dust in the absence of explosive gas has been shown in numerous cases in mines and mine plants and also by a series of tests. In these tests a dense cloud of dust is blown onto an open flame or an electric arc, almost invariably with resultant exploding of the dust. The Safety Division of the United States Bureau of Mines has made a number of demonstrations of the explosibility of Pittsburgh coal-bed dust, using a small gallery or box in which a cloud of coal dust is blown onto a lighted match; larger-scale tests have been made with an electric arc as the igniting agent. Bituminous-coal dust is readily ignited with a medium arc, but with low-volatile coals a larger arc is required. For test purposes, a 100-ampere arc has been used. Ignition has occurred readily under these conditions with Pocahontas No. 5 coal dust with ratios of volatile to total combustible of 0.232 to 0.253, and with Pocahontas No. 3 coal dust with a combustible ratio of 0.242. Lower Kittanning coal dust, with a ratio of 0.187, did not give definite ignitions, and Pocahontas No. 4 dust did not explode, although part of the coal-dust cloud ignited. It is probable that even the low-volatile coal dust will be found to be explosive with a higher-amperage electric arc as the initiating agent."

Jul 1, 1936

By P. B. Altringer

The Bureau of Mines conducted laboratory tests to devise a procedure for recovering a marketable grade of tungsten from the brine of Searles Lake, Calif. The brine contains only 56 parts per million of tungsten (70 parts per million of W03). Using ion exchange resins synthesized by Bureau chemists, 98 percent of the tungsten was extracted from the brine and 92 percent of the tungsten was recovered as a marketable iron-tungsten concentrate containing 44 percent tungstic oxide. Although major technical problems have largely been resolved, research is progressing to escalate testing in a process-development unit to provide more reliable data for an economic appraisal.

Jan 1, 1978

By H. O. McDonald

The Bureau of Mines has demonstrated a hydrometallurgical method to separate chromium from other metals in a variety of surface-finishing wastes by precipitation with benzoate ion. The resulting chromium salt may then be converted to the hydroxide, and the benzoate may be recycled. Chromium recoveries of 92 to 100 pct are obtained.

Jan 1, 1983