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By ALICE V. Petar

Among the rarest of the rare metals are four that are linked together by a common historical background as well as by chemical relationship. With the excep- tion of indium, these metals are likewise characterized by the patriotic nature of the names given them by their discoverers. The existence of gallium, germanium, and scandium, was predicted by the Russian cherist, D. I. Mendeleeff some time prior to their discovery; and these elements might well have been overlooked, had not the search been stimulated by the urge to confirm the scientific hypothesis of their existence. Nowhare found in sufficient quantities to attract attention, these little known elemente are nevertheless widely distributed in the earth's crust. So far they are found commercially mostly in the sulphide ores of zinc and must be considered as being largely curiosities of the zinc smelter. Recent progress in electrolytic zinc refining, however, now gives promise that the way may be open for the recovery of these very rare metals in larger quantities-- possibly in quantities sufficient to permit of their finding commercial utilization.

Nov 1, 1930

By Albert E. Long

Preliminary experiments conducted in 1949 with a few diamond bits in which the diamonds in the bit crowns were set in hard-vector directions indicated that a substantial saving could be effected when a high percentage of the diamonds were oriented in this-manner. It was realized, however, that many additional tests would have to be performed before a positive trend could be established and the possibility of coincidence eliminated. Therefore, a long-range series of experiments was planned to investigate various phases of the problems related to the orienting of diamonds in diamond bits. This report (the third in a series) 2/3 presents the information obtained from tests conducted to investigate more fully the effects of orienting high-grade drill bort in diamond bit crowns. In these tests, the drill bort were oriented in both hard-vector and soft-vector directions in the crowns of AX-size bits. Test drilling was done in a dike of saussuritized dacite porphyry similar to a fine-grained granite in hardness e drillability.

Jan 1, 1954

By M. N. Plis

This report describes the initial results of long-range research on bit life conducted by the Bureau of Mines. Three commercial bit designs -a round-nose radial, 60° conical, and 90° conical with tungsten carbide (WC) inserts -and five experimental bits were tested. Four of the experimental bits were radial designs using polycrystalline diamond compact (PDC) inserts. The fifth was a 90° conical with an oversize WC insert. Bits were worn on a high-silica sandstone typical of coal mine roofs. The bits were mounted on a 34-in-diam drum section that provided a bit speed of 565 ft/min. Cutting forces were measured on a modified vertical slotter using a three-axis force dynamometer and recorded on an FM magnetic tape recorder. Changes in cutting forces, bit weight, and airborne dust due to gradual abrasive wear and catastrophic insert failure are presented. Tabulated and graphed data, photographs of the progression of bit wear, and selected qualitative visual and auditory observations of the bits taken throughout the experiment are found in the appendixes. The results show that bit life ranged from approximately 16,000 ft for the WC round-nose radial bit to over 125,000 ft for a PDC round-nose radial. Performance, in terms of bit life, cutting forces, wear rate, frictional sparking, machine vibration, and noise was in general best with the PDC bits, followed by the rotating WC bits, with the nonrotating WC bits (round-nose radial and locked 60° conical) being the worst. The results show variations in the included tip angles of new conical bits have an insignificant influence on bit performance when the effects are averaged over the life of the bit. In addition, new bits were generally found to entrain more primary respirable dust for a given cutting distance than worn-out bits. It is hypothesized that this is due to the difference in frictional behavior between new and worn bits. The results from these tests are being used in the Bureau's cutting system model (CSM).

Jan 1, 1988

By Emery Chilton, Charles Taylor, Mark Senk, Linda McWilliams

Three-axis ultrasonic anemometers are used to study airflow in the NIOSH ventilation gallery where ventilation in an underground mine is simulated. In this study, performance characteristics of this anemometer are evaluated and the effects of sensor orientation and sampler location on flow readings are examined. The study results provide guidelines for more effective use of the ultrasonic anemometers in the ventilation gallery.

By G. Esterhuizen, C. Karacan

Methane can be a significant hazard in coal mine longwalling operations and extensive methane mitigation techniques are employed by coal mine operators. Reservoir modeling techniques are used to better understand the liberation and migration of methane from the surrounding rocks towards the mine ventilation system. The caved rock behind the advancing longwall face, known as the gob, can contain high void ratios, providing high permeability flow paths to the methane. The gob is progressively compacted by the weight of the overburden, resulting in a reduction in the void ratio and associated permeability. Estimating the permeability distribution within the gob poses challenges due to its complexity. The authors have developed a new methodology to determine both horizontal and vertical variations in the permeability of the gob. Variations of the permeability in the vertical direction are based on a model of caving and block rotation, which considers the effect of block dimensions and fall height on the void ratio. Gob compaction by the overburden and associated permeability changes are determined from a three-dimensional geo-mechanical model which simulates the gob as a strain hardening granular material. The resulting three-dimensional permeability distribution in the gob is then transferred to a reservoir model. The paper demonstrates the application of the method and shows that reasonable results are obtained when compared to empirical experience and measurements.

By R. V. Lundquist, H. Leitch

Two hydrated calcium aluminates , formed by side reactions in the leaching step and desilication step of the lime- soda sinter process , were investigated to better define their influence on alumina recovery . The two calcium aluminates , Caз [ Al ( OH) 6 ]₂ and зCa0.Al½ 03 · ( 8-12 ) H₂ ) , were prepared and identified by chemical and X- ray analysis . The relative proportions of each of these compounds formed in typical leach solutions at several temperatures were determined . The influence of free lime as a promoter of calcium aluminate formation was also investigated . The formation and precipitation from leach liquors of calcium aluminates contributes to the low alumina recoveries in the process . The presence of carbonate ion in the leach solution suppresses calcium aluminate formation and precipitation and results in higher alumina recovery . Hydrated calcium aluminates are formed in the aging of lime - soda sinters in the normal atmosphere .

Jan 1, 1963

By J. Roger Loebenstein

This report presents a U.S. Bureau of Mines study of the flow of arsenic-containing materials in the United States, based on the best data available in 1991, includes a consideration of arsenic as a byproduct of the processing of nonferrous metals, the fate of arsenic in manufacturing wastes, the quantity of arsenic used in products, tile fate of arsenic in dissipative uses, and the useful life of discarded products. Where possible, estimates are given of the amounts of arsenic lost from the materials flow. Arsenic byproduct of mining nonferrous metals. Historically, most U.S. production has been from the states of Montana, Washington, and Utah. The smelters in these states are believed to be the areas of the country where arsenic is most concentrated in the soil, tailings ponds, and waste dumps. Since the closure of the last domestic producer of arsenic in 1985, all arsenic has been derived from imported sources. Historically, arsenic was important in agricultural applications as an insecticide, herbicide, and cotton desiccant. As the environmental movement gained momentum and the toxicity of arsenic became better understood, most of the agricultural uses for arsenic were banned. Beginning about 1975, the use of arsenic as a wood preservative began to grow. After 1980, wood preservative uses became more important than agricultural applications. By 1990, 70% of the arsenic consumed in the United States was used by the wood preservative industry and 20% by the agricultural industry. The major source of domestic arsenic emissions in 1989 was from the U.S. copper processing indus¬try. About 7,800 mt/yr of arsenic was discarded in leach dumps, tailings, and slag. Another 800 mt/yr was liberated to the atmosphere and 1/100 mt/yr was exported in copper concentrates. On the consumption side, 9,200 mt/yr was lost, mostly from dissipative agricultural uses and the disposal of obsolete arsenical products.

Jan 1, 1994

By Oliver Bowles

A conviction is growing that depressions and other adverse conditions are not entirely unavoidable if a knowledge of past achievements and shortcomings is intelligently, applied in shaping the course of industry. Mineral producers have available a source of such knowledge concerning; their industry in the statistical records of the United States Bureau of Mines, and by scanning, this increasingly exact history can obtain information on which to found a more stable future. This paper contains a brief history, covering more than 50 years, of the activities of the nonmetallic mineral industries as a group, followed by short histories of each of the more important commodities in which are noted the circumstances that lave influenced their development.

Jan 1, 1933

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By Alvin Kaufman

Geothermal plants are competitive with conventional units. A geothermal plant can produce electric energy for 6.70 mills per kwhr, compared with 6.96 mills for coal, 6.74 mills for oil, and 7.04 mills for gas. These costs include fixed and variable charges. Potential for geothermal power exists in the Western United States, Alaska, and possibly Hawaii. Assuming that the current downward trend in cost per kilowatt of coal will cease and that the relative cost of gas and oil, already trending upward, may rise considerably more, geothermal energy will be utilized where available, in producing electric energy. It will be used in California first because it is directly competitive with gas-and oil-fired installations there. A long-term appraisal is difficult because little is known about the sources of geothermal power and the electric generating capacity which the steam fields will support. However, a market for geothermal steam-generated electricity exists within the Western States.

Jan 1, 1964

By Oliver Bowles

The United States has never attained importance as a producer of asbestos, the domestic output being only 1 to 3 percent of the quantity required to supply raw material for its extensive asbestos-product manu- facturing industries. Production is centered in four principal countries-- Canada, Rhodesia, Union of South Africa, and the Soviet Union. Since asbestos first became an important commercial commodity the Province of Quebec, Canada, has led in tonnage produced, but a large proportion of the output of this province is shorter, nonspinning grades. Since 1916 the Union of South Africa and Rhodesia have become increasingly important as sources of the higher-grade spinning fibers. Before the World War Russia ranked next to Canada as a producer of asbestos, but during the revolution- ary period the industry in that country was almost at a standstill. In 1926, however, activity was revived, and each year since then production and exports have increased greatly. Minor quantities of asbestos are produced in Cyprus; Australia, Finland, and several other countries. Chrysotile is the leading product in all the producing countries, but substantial quantities of both blue (crocidolite) and brown (amosite) asbestos also are produced in the Union of South Africa. Minor quantities of anthophyllite and similar amphibole varieties are mined in the United States, Italy, Bulgaria, Finland, and several other countries.

Jun 1, 1934

By Paul H. Mutschler

The Bureau of Mines sponsored a study of the impact of changing technology on the demand for metallurgical coal and coke to 1985. Individual technologies were analyzed to determine what effect each had on the demand for and the consequent consumption of metallurgical coal and coke in the steel industry. The domestic steel industry demand for metallurgical coal and coke for the production of hot metal will probably increase through 1985. Formcoke if implemented on a worldwide basis could begin to supplant the U.S. export market for metallurgical coal. The major technologies that have contributed to the decline in demand for metallurgical coke per ton of hot metal are (1) the increased usage coupled with higher iron content of agglomerates, (2) modification of blast furnace practices such as high top pressures and blast temperatures, and (3) increases in the injection of supplemental fuels. The projected demand for metallurgical coal and coke under current technology for 1985 are 109.4 and 76.0 million tons, respectively. With future technology implemented, the demand for metallurgical coal and coke will be 82.0 and 56.9 million tons, respectively. The projected domestic demand for metallurgical coke could further decrease by as much as 15 to 20 million tons by 1985 if formcoking proves technologically and economically feasible.

Jan 1, 1975

By C. H. Riggs

This report describes the geology and reviews the oil-production history of the Dutcher sands of Pennsylvania age in the Muskogee oilfield. The geology and production history are presented not alone as a review of the past behavior of the field but also to interpret the possibilities for future production of oil from semidepleted sands in this and similar areas. The Muskogee field, one of the oldest oil-producing areas in Oklahoma, yields paraffin-base oil of 40° API gravity -a gravity higher than that of most Oklahoma oils. Oil was discovered in the townsite of Muskogee in 1894 but was not produced in commercial quantities until 1904. A peak yearly rate of 1,340,000 barrels of oil was attained in 1910 (see table 1).

Jan 1, 1959

By Carl Belser

Approximately 30 million pounds of tungsten trioxide in the form of ferberite concentrates have been shipped from Boulder County. Since 1940, the production has varied considerably, being affected by the emergency needs of World War II and the Korean conflict. During World War II, attempts to stimulate production were made by the Metals Reserve Company by stabilizing the price for a specified period, the Reconstruction Finance Corporation by small mining development loans, and the Bureau of Mines and the Geological Survey, who cooperatively explored some of the district by surface and underground core drilling. During the Korean conflict and continuing through the first half of 1954) tungsten production was being stimulated by a Government-gauranteed price and by financial assistance loans under the Defense Production Act of 1950 to qualified operators of properties that have merited exploration. This combined program has increased production in Boulder County from about 1,900 pounds in 1949 to an estimated 383,000 pounds of tungsten trioxide in 1953. The 1953 production came from 67 properties. One of the problems confronting producers is the need for improved beneficiaton methods. Ores from the area have not been amenable to flotation concentration and gravity methods have resulted in poor recovery, often less than 70 percent.

Jan 1, 1955

By Herbert H. Einstein

Rock mass deformability is commonly predicted using correlations with RQD or other indices of rock mass quality, or by extrapolation from large in-situ tests. Based on the probabilistic description of rock masses empirically developed in Part I a new approach was attempted in modeling for predictions of deformability. This approach decomposes the rock mass into spatially variable joints described by probability distributions, and intact rock blocks. Stiffnesses and elastic parameters are associated with the joints and intact blocks respectively, and deformations built up by adding the contributions of each. This model allows relaxation of many of the simplistic geometric assumptions which constrain parallel attempts to model deformation in rock masses. The model has been applied to four standard cases in order to test its results against previously existing models, and to check whether it replicates empirical correlations. When joints are taken as parallel, common empirical correlations are closely approximated by the model output. However, the closeness to empirical correlation breaks down when variability of the jointing geometry is increased.

Jan 1, 1979

By V. Castranova, T-M. Ong, V. Vallyathan, M. J. Keane, W. E. Wallace Jr.

"Inhalation of certain forms of silica, asbestos and some other respirable dusts can result in pulmonary fibrosis, characterized by destruction of the surfaces of alveoli and respiratory bronchioles. Fibrous thickening of the alveolar septa decreases the lung's capacity for gas exchange.Pulmonary macrophage damage by respired dust may initiate the fibrotic response.In one proposed mechanism, dust particles interact with the plasma membrane of a macrophage. This damages the cell or induces some hyperactivity of the cell, resulting in excessive release of lysosomal enzymes and reactive forms of oxygen (1). These reactive enzymes or radicals then damage the alveolar surface epithelial cells. A second mechanism has also been pro¬posed (2,3) in which dust damage to the macrophage causes the release of mediator substances which induce pulmonary fibroblast cell proliferation and increased collagen synthesis. This produces fibrous tissue in the terminal air spaces (4,5).Mineral surface interactions with plasma membrane lipoproteins have been proposed as a mechanism of lytic damage of pulmonary cells by silica dust in numerous models (6,7). The significance of dust surface proper¬ties has been further revealed in studies showing significant changes in dust induced cytotoxicity as a function of dust surface crystallinity and organic or inorganic contamination or coating of mineral surfaces (8,9). Such modification of the mineral surface might interfere with surface sites responsible for the toxicity of dusts for pulmonary macrophages, thus interrupting the early stages of the process of fibrosis.In vitro cellular assay systems using erythrocyte hemolysis or the release of macrophage cytosolic or lysosomal enzymes following dust challenge, have been used to analyze the initial mechanism of dust damage to cells. However the ability of these assays to predict the pulmonary disease producing potential of various dusts is imperfect owing to some ""false positive"" results. These assays as performed are therefore questionable models for the initial lesion in pneumoconiosis or silicosis. In particular, kaolin frequently is found to have comparable biological activity to silica quartz in these assays (10,11).Silica and kaolin have distinctly different fibrogenic potentials. Silica is highly fibrogenic, resulting in both acute and chronic silicosis (12). Some epidemiological data and animal experimentation data have indicated that long term exposure to kaolin can result in pneumoconiosis; however, kaolin is relatively benign as compared to silica (13-18). Kaolin is also of interest because it is one of the major mineral inclusions in Eastern U.S. bituminous coals. We have observed that exposing respirable sized native silica or kaolin for two hours to pulmonary macrophages results in a greater enzyme release for kaolin exposures, on a dust mass basis. Exposure of erythrocytes to the dusts also results in greater levels of hemolysis by kaolin for equal mass respirable dust doses. Therefore, these results do not correlate positively with known disease inducing potentials of the two dusts.Characterization of physical and chemical surface properties of dusts involved in occupational exposures, and characterization of the alteration of those surface properties which are likely to occur upon deposition of the dust in the lung, should improve the identification of respiratory disease hazards.Inhaled dust particles deposited in the lower respiratory tract will come in contact with pulmonary surfactant. This surfactant forms a surface film on and emulsion in the liquid hypophase coating of the alveoli and respiratory bronchioles. The primary constituent of this pulmonary surfactant is the lipid diacyl glycerophosphorylcholine, lecithin (19). Because this lipid is also a major component of cell membranes, it is possible that surfactant can interact with mineral dust to alter its Interaction with macrophages and other pulmonary cells and, thus, it"

Jan 1, 1988

By Lewis M. McNay

Description of methods employed and cost data are given for surface-mined land reclamation in Moraine State Park, Butler County, Pa. This project was conducted under the authority of the Appalachian Regional Development Act; a total of 177 acres of land was rehabilitated for specific land use purposes. The use of large equipment expedited the project work, and similar results could be anticipated on similar reclamation programs.

Jan 1, 1970

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in Saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigations beginning with No. 4251, of which this is the third. The data are accompanied by maps showing the location of holes drilled and deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township-map. The description of each half township is followed by a description of each deposit developed in that half township.

Jan 1, 1948

By J. A. Herdlick

The Star mine, near Neihart, Cascade County, Mont., has been in continuous operation since the construction of a 50-ton bulk flotation mill in 1939. The mine was examined by G. N. Bennett, an engineer of the Bureau of Mines, in November 1942. At that time the life of the operation appeared to be limited and a program of crosscutting and core drilling were recommended. The program had as its objective the investigation of a promising undeveloped area lying west of the Star vein and, if possible, the development of enough reserves in this area to insure continuous operation during the war emergency. Development of additional reserves would then justify necessary changes in the mill in order to eliminate the heavy penalties imposed for excess zinc in the bulk concentrates. The Bureau of Mines work began in February 1944 and was completed in September 1944. The project was started by Wilder R. Brinton and continued by Thomas W. Oster, mining engineers in the Bureau's Montana district office. Beneficiation tests on are and concentrates were made after completion of the underground work. This report presents the factual data obtained during all phases of the Bureau's investigation.

Jan 1, 1949

By S. C. Schaefer

The Bureau of Mines investigated tIle standard Gibbs energies of formation, 8Gfo, for MllF2 (manganese difluoride) and CoF2 (cobalt difluo-ride). High-temperature galvanic cells employing CaF2 (calcium diflu-oride) as the solid electrolyte were used to measure the open-circuit potentials for the cell reactions ?

Jan 1, 1985