Search Documents

By D. Harrington

Most of those in the Health and Safety Branch, Bureau of Mines, necessarily participate in activities associated with essentially all phases of the mineral industries, including coal and noncoal mines, quarries, smelters, metallurgical plants, and various petroleum operations. One of the strictly war activities of the branch - the Explosives Control Division, which administers the Federal Explosives Act of December 26, 1941 - has functions that require contacts not only with nearly all phases of the mining and allied industries but also with those engaged in scores of other occupations that manufacture, store, use, or possess explosives, or many of the ingredients of explosives. The field men of the Health and Safety Branch (approximately 300 in number) Are occupied full time in health and safety activities and annually make thousands of contacts with people in the mineral industries as well as the plants in which they work. From these they formulate several thousand written reports containing sources of thousands of conclusions and recommendations aimed at reduction of health end safety hazards in these industries. Although such activities have been greatly increased during the war and immediate pro-war periods, they have been in effect to a considerable extent since the Bureau of Mines was created in 1910.

Jan 1, 1944

By G. W. Jones

In the course of experiments on the stabilization of acetylene gas by addition of other gases, notably hydrocarbons such as methane, propane, and butane, it was observed that large quantities of carbon black are produced during the explosion of acetylene or mixtures of acetylene with the, above hydrocarbons, the added hydrocarbon being essentially decomposed into hydrogen and carbon. It is known that in the complete absence of air acetylene explodes upon application of an intense ignition source at pressure above 5.9 p.s.i. gage. The same is true of mixtures of hydrocarbons and acetylene. However, the pressures necessary for explosion are considerably higher in the case of these mixtures and depend on the amount of added hydrocarbon. The present report contains data on gaseous products and the physical characteristics of the carbon black formed by explosion at elevated pressures of various mixtures of acetylene and hydrocarbons as well as other gases, such as hydrogen, helium, nitrogen, and carbon dioxide.

Jan 1, 1950

By Thomas O. Glover

Economic growth in Cameroon was restricted during 1987 owing to a decrease in oil prices during 1986 and the falling value of the U.S. dollar in 1987. The yearly budget reflected a significant drop in revenues and expenditures. Taxes on imports and some exports were increased to raise revenue. The shortage of revenue and the lack of liquidity had restricted the Government's operation and investment programs. External public debt reached an estimated $3.2 billion2 representing 20.8% of the estimated gross domestic product (GDP) of $12.3 billion. The Government operated at an 8.7% deficit in 1987. The GDP growth rate had fallen to 0.6% in 1987 and was projected to remain at that level in 1988. Economic planning was managed through a series of 5-year plans. The country was under the sixth 5-year plan, which would end in 1991. The plan stressed balanced development as one method to achieve the desired results. Sources of revenue for the year included direct and allied taxes (31.2%). customs collections (31.0%), and oil royalties (28.0%). The oil royalties in 1987 represented a larger part of the budget than in 1986. In January 1987, eight African oil exporting countries, including Cameroon, formed the African Petroleum Producers' Association (APPA). The eight countries represented about 80% of the total African oil production of 5.2 million barrels per day in 1987. Cameroon produced approximately 3% of total APPA oil production. Cameroon produced approximately 68.5 million barrels of crude oil in 1987, slightly less than that produced in 1986. Earnings also fell in 1987, not only from falling production, but also from declining oil prices and the fall in value of the U.S. dollar on world markets. Oil had been the main stimulus of Cameroon's growth throughout the past decade, and a key generator of export revenues and financial resources for the economy.

Jan 1, 1989

By Sandeep K. Sharma

The U.S. Bureau of Mines has been investigating new techniques to improve the of mineral to recover water lost in the waste slurry, and to produce dewatered solid dewatering s suitable for disposal. As part of this investigation, a study was undertaken to investigate the feasibility of dewatering Alaska placer effluent. Based on the laboratory tests, preliminary field tests were conducted on three placer mines in Alaska. At these mines, the water recovered from the placer effluent (250 to 23,000 NTU) exhibited turbidities of 20 to 240 NTU. In the second year of the project, a large-scale dewatering unit was set up at a mine located in the Livengood district. The feed, at flow rates up to 935 gpm, was mixed with dilute PEO solution in a flexible plastic hose with and without static mixers. Feed to the dewatering unit generally ranged between 300 and 26,500 NTU and required PEO dosages of 0.02 to 0.14 lb per 1,000 gal to produce water from the screen underflow with turbidities of 20 to 50 NTU. During this period, a small unit was also operated at Dow rams of 10 to 25 gpm at sewn sites throughout Alaska, with the effluent from four of the sites being dewatered successfully.

Jan 1, 2010

By P. G. Bennett

The Bureau of Mines developed a process using ion exchange to recover cobalt from spent copper leach solutions. A preliminary economic evaluation of the process indicated that about one-third of the capital cost was attributed to the total resin inventory, and one-third of the operating cost was required for reagents to remove iron from the ion-exchange eluates. An agitated Pachuca elution system was investigated in place of a fixed-bed elution system. The Pachuca system reduced the resin inventory by 27 pet when compared with the fixed-bed elution system. Processing fresh spent copper leach solution reduced the resin inventory by 20 pct and resin iron loading by 80 pct. Reagent requirements for removing iron from the eluates were decreased because less iron was extracted. The Pachuca system, along with processing fresh spent copper leach solution, reduced the total resin inventory by 47 pct. A revised cost evaluation of the cobalt recovery process was obtained to determine the effects of these process modifIcations. The estimated total capital cost for a plant processing 10,000 gpm of spent copper leach solution containing 26 ppm Co was $23.1 million. With credits for nickel, zinc, and copper byproducts, the estimated net operating cost was $5.10/lb of cobalt.

Jan 1, 1988

By Allen D. Look

Uninterrupted shaft operations are an important economic factor in mine operation, and good shaft support is an important aid in preventing accidents and interruptions. More permanent supports can cut the hazards, costs, and delay incident to replacement of conventional timbers, especially where subject to decay. Installation of prestressed, precast concrete shaft supports in 100 feet of shaft at the Banner mine, Lordsburg, N. Mex., nave a satisfactory permanent installation in a section of shaft that had given trouble with conventional timbering. Use of rock bolts supporting gunited wire netting around the rock walls of the shaft prevented sloughing. No attempt was made in this paper to arrive at comparative costs of installation of various types of support. However, it was indicated that use of a lighter weight aggregate would be desirable in further use if prestressed precast members as placed in the Banner mine.

Jan 1, 1957

By R. J. Bielicki

A sorption apparatus for measuring the equilibrium sorption isotherm and the rate of diffusion of methane from fine-sized coal was designed and constructed. Preliminary work that used Pittsburgh and Pocahontas No. 3 coal shows that the diffusion coefficient varies with pressure and that the fracture spacing in these two coals is substantially different.

Jan 1, 1972

By F. N. Kissell, R. J. Bielicki, J. H. Perkins

A sorption apparatus for measuring the equilibrium sorption isotherm and the rate of diffusion of methane from fine-sized coal was designed and constructed. Preliminary work that used Pittsburgh and Pocahontas No. 3 coal shows that the diffusion coefficient varies with pressure and that the fracture spacing in these two coals is substantially different.

Jan 1, 1972

By Jr. Norman

Thermoelectric properties of depleted uranium selenides and tellurides were investigated from room temperature to 700 C. Several depleted uranium monoselenides and monotellurides were doped with selected cationic and anionic materials to determine the effect of impurity additions on the thermoelectric properties. The undoped uranium selenides and tellurides were semimetallic conductors exhibiting low Seebeck coefficients and electrical resistivities. Partial or complete degeneracy was in evidence, indicating a charge carrier energy distribution similar to that in a metal. Doping increased the Seebeck coefficients of the uranium monoselenides and monotellurides; however, the corresponding change in the power factor in the figure of merit was small because of the increase in electrical resistivity.

Jan 1, 1965

By Alla D. Mah

The energies of combustion of zirconium carbide and hafnium carbide were measured by combustion calorimetry and the heats of combustion and formation. of zirconium carbide and hafnium carbide were derived . The results are-- ZrC AH298.15 ( combustion) = -308.60 ± 0.55 kcal /mole , AH298.15 ( formation) -47.0 ± 0.6 kcal /mole , AH298.15 = HfC (combustion ) = -306.08 ± 0.20 kcal/mole , AH298.15 ( formation) -52.3 ± 0.4 kcal /mole . = INTRODUCTION This report contains the results of calorimetric measurements to obtain the heats of formation of zirconium carbide ( ZrC) and hafnium carbide ( HfC) . The work was conducted as part of a Bureau of Mines program for determining the heats of formation of oxides , carbides , and nitrides by combustion calorimetry . Combustion calorimetry is one of the most precise calorimetric techniques . The chief obstacle to obtaining accurate heat of formation values for carbides , and the chief reason for the variation in the results of different investigators , is the lack of purity of the carbide samples . Corrections for impurities always involve assumptions which lead to uncertainties . In general , a large impurity correction is accompanied by a large uncertainty in the final result .

Jan 1, 1964

By Chase E. Sutton

The porosity of a sand is usually the measure of its capacity for holding fluid, although porosity is sometimes selective; that is, a small percentage of the actual pore space (voids), particularly in fine-grained sandstones, may be isolated by the cementing material which prevents the entrance of fluids under normal conditions. Obviously, however, porosity determinations are essential to an engineering study of underground conditions of an oil field, and a simple and reliable method of obtaining a reasonably accurate figure for average porosity is desirable. This report describes a method suggested by Ruasell,3 which was used by the writer in the preparation of a report on the Texhoma-Gose pool, Archer County, Tex.4 The conditions in this pool were particularly favorable for obtaining an average porosity figure, in that some 30 to 35 core samples of the pay sand were available for analysis.

Jan 1, 1928

By P. G. Clites

This study was conducted to determine the patterns of heat transfer to water-cooled copper crucibles during vacuum arc melting. Values of heat flux from the ingot to the crucible were determined during nonconsumable electrode vacuum arc melting of zirconium and during consumable electrode vacuum arc melting of titanium) zirconium) and steel. The results of these studies con-firm the existence of a high thermal resistance between the ingot and the crucible wall which results from the shrinkage of the ingot as the metal solidifies. Maximum heat flux occurs near the top of the ingot where maximum values of heat flux of 1.4 X 106 Btu/ft2 hr were observed during small-scale consumable electrode arc melting of zirconium and titanium. The maximum heat flux for consumable electrode arc melting of 8-inch-diameter ingots was 0.5 X 106 Btu/ft2 hr. The effects of electrode material) electrode diameter) arc current) and arc potential on heat flux from the ingot to the crucible were studied. Data were also obtained on crucible wall temperatures and on the effect of very narrow annular water jackets.

Jan 1, 1967

By R. N. Love, L. Goldman

"INTRODUCTION When tannin is present in a boiler water, it causes certain difficulties in many analytical testing procedures because of its colloidal action in interfering with the removal of suspended matter by filtration and also because of the color it imparts to the boiler water.For example, in any test for phosphate in boiler water the first step is to filter out of the sample all sludge and suspended solids. Calcium phosphate in the sludge would give high results if not completely removed. If tannin is present in the sample, the sludge and suspended matter tend to pass through the filter paper so that it is difficult to remove it all. It may even be that tannin makes some of the suspended material in the sample completely nonfilterable. If this is true, it would be necessary to destroy or remove the tannin from the sample before filtering to get complete removal of calcium phosphate from the sample. In addition, if the test used is a colorimetric one, the tannin causes interference by its own color.As the calorimetric phosphate test is so convenient for control purposes and the use of tannin for boiler water treatment has become common, it has become necessary to develop suitable methods for employing the colorimetric phosphate test for boiler waters containing tannin. In this paper three different methods for doing this arc described and studied."

Oct 1, 1946

By N. S. Dalal, X. Shi

While it is known that vanadate and related compounds of pentavalent vanadium ( V (V)) exert potent toxic effects on a wide variety of biological systems, the underlying biochemical mechanism is still not fully understood ( 1- 3). One of the pathways is thought to involve the oxidation of NAD ( P) H. Thus, considerable effort has been devoted to finding the mechanism of NAD ( P) H oxidation by Vcvi (1-15). Erdmann et al. (5) first noted that vanadate stimulated the oxidation of NADH by plasma membranes and attributed this effect to a membrane containing NAD(P)H-dependent V(V) reductase. Later studies by Liochev and Fridovich indicated that endogenous superoxide ( 02 ) plays a central role in this reaction ( 4, 12, 13) . They proposed that NAD ( P) H dehydrogenases or oxidases produce 02, which causes VCV ) to stimulate NAD ( P) H oxidation via the following free radical chain mechanism ( 4, 12, 13) :

Mar 1, 1992

By John H. Soulé

"INTRODUCTION Spodumene and lepidolite were shipped from the Harding pegmatite deposit, Taos County, N. Mex., in the period from 1930 to 1930. Tantalum minerals were noted as early as 1924 and described in 1931 3/ but no tantalum ore was shipped until 1942. The deposit was mapped and studied by geologists of the Federal Geological Survey and engineers of the Bureau of Mines late in 1942 and early in 1943, and a Bureau of Minus exploratory project was carried out in 1943. 4/ Thu following report presents the results of that project.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Minos has as its primary objective the more effective utilization of our mineral resources to the end that they make the greates possible contribution to national security and economy. It i the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lovell B. Moor, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallugiical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, Assistant Director."

Dec 1, 1946

By Charles L. Kimbell

The final 26 tables of this chapter, tables 25-50, extend and expand the statistical series on production that was started in the 1963 edition of the "Area Reports: International" volume of the "Minerals Yearbook" and that was subsequently updated and expanded in the 1965 and 1967-89 editions. Continuing the practice started in 1989, a column has been included in each of these tables providing a 5-year average for 1986-90, inclusive. This should provide a clearer picture more rapidly of the role of each major producer over the 5-year period. The listing order of major producers, however, continued to be, as in past years, in descending order of rank in the year of review, 1990. With the inclusion of silver and uranium in the 1988 edition of this chapter, this group of tables now includes each of the crude minerals that ranked from 1st to 19th in 1983 terms of value of their output (as well as four others of lesser rank). These 23 crude mineral commodities accounted for 93% of the estimated value of world crude mineral production in 1983. In addition, world output of five key downstream products-aluminum, steel, cement, nitrogen in ammonia, and refined oil-are included because of their significance as products.

Jan 1, 1993

By E. G. King

Existing thermodynamic data for compounds of the rare-earth metals are few in number and often inaccurate because, in the past, it was difficult to obtain samples that were pure enough and reasonable in cost--a situation that is rapidly improving. This paper reports the results of low-temperature heat-capacity and high-temperature heat-content measurements for cerous fluoride (CeF3) and supplies the first such published data for a rare-earth fluoride. The low-temperature heat-capacity data cover the temperature range 51°-298° K. and serve to evaluate the entropy at 298.15° K. The high-temperature heat-content data cover the temperature range 298°-1,799° K., including the temperature and heat of fusion. The results are assembled for ready use in thermodynamic calculations. Cerous fluoride is one of the important intermediate compounds in the production of cerium metal.

Jan 1, 1959

By William E. Dennis

"INTRODUCTION The San Antonio Canyon prospect was examined by engineers 3/ of the Bureau of Mines in March 1943 and again in October 1944. In July 1944, the United States Geological Survey mapped the prospect and submitted a report 4/ recommending core drilling by the Bureau of Mines. The drilling project, which was supervised by the author, was started on January 10 and completed on May 10, 1946.ACKNOWLEDGMENTSIn its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests. Acknowledgment is made to W. D. McMillan, engineer in charge of the Austin field office, and to J. H. Hedges, chief of the Tucson Division, Mining Branch, for general direction and advice. The samples were analysed in the laboratory of the Metallurgical Branch at Rolla, Mo., C. Travis Anderson, chief."

May 1, 1947

By Frank B. Fulkerson

A study was made of the economic factors governing silver production in the Coeur d'Alene mining region, Shoshone County, Idaho. Production and other stat is tics were analyzed. It was concluded that if the rapid rise in the open market price that began late in 1961 continues, greater production of the metal should result from the mines of the Coeur d?Alene mining region. However, the output gain would be limited, because costs per ton of ore mined would rise as production was increased beyond optimum capacity. Advances in the price of silver would increase the size of ore reserves by making some marginal ore profitable to mine and by providing greater funds for exploration projects that might result in discoveries adding to the reserves. Output of byproduct silver from lead-zinc mining probably will not exceed 4.3 million ounces, judging from the trend from 1946 to 1961.

Jan 1, 1964

By Frank B. Fulkerson

A study was made of the economic factors governing silver production in the Coeur d'Alene mining region, Shoshone County, Idaho. Production and other statistics were analyzed. It was concluded that if the rapid rise in the open market price that began late in 1961 continues, greater production of the metal should result from the mines of the Coeur d'Alene mining region. However, the output gain would be limited, because costs per ton of ore mined would rise as production was increased beyond optimum capacity. Advances in the price of silver would increase the size of ore reserves by making some marginal ore profitable to mine and by providing greater funds for exploration projects that might result in discoveries adding to the reserves. Output of byproduct silver from Lead-zinc mining probably will not exceed 4.3 million ounces, judging from the trend from 1946 to 1961.

Jan 1, 1964