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By Albert H. Clough

The West Lynn Canal subarea of the Juneau Mining District (JMD) is defined by Lynn Canal on the east, Davidson Glacier to the north, Icy Strait to the south and the Glacier Bay National Park Boundary to the west (figs. C-l and C-2). This area extends along the main-land west of Juneau (across Lynn Canal) northerly, to approximately 20 miles south of the city of Haines. The only roads in the area are relatively new logging roads at the southern end constructed to support a U.S. Forest Service timber sale. There is also local road access near the community of Excursion Inlet. Access to the remainder of the region is either by boat, aircraft, or 'foot. Helicopters provide the only time effective access to all but the coastal parts of the West Lynn Canal subarea. Coastal areas may be reached by small boat or float aircraft. There is an unimproved dirt airstrip just north of the mouth of the Endicott River. This airstrip is suitable for use by light aircraft. The subarea lies within the Tongass National Forest and is managed by the Department of Agriculture, U.S. Forest Service. Approximately two-thirds of the forest lands are open to mineral entry under the current Tongass Land Management plan. The remaining forest lands comprise the Endicott River Wilderness area, which is closed to mineral entry. Private lands within the study area are sparse, with scattered homestead tracts along the coastal regions and in the Excursion Inlet area. Sealaska (Southeast Alaska Regional Native Corporation) also has land selections in the southern Chilkat Range. Tidal and submerged lands are owned by the State of Alaska.

Jan 1, 2012

By Richard A. Winters

In 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 34,680-acre Lime Canyon Wilderness Study Area (NV-050-231) to evaluate its identified mineral resources. The Wilderness Study Area is in Clark County, NV, about 30 air miles southwest of Mesquite, NV. The area studied contains an estimated 44 million tons of indicated subeconomic resources of gypsum, an inferred subeconimic resource of limestone and dolomite, and occurrences of gold, copper, uranium, and zeolite. The Wilderness Study Area is underlain chiefly by carbonate rocks with lesser amounts of sandstone and shale. Metamorphic, granitic, and volcanic rocks also crop out within the area. Large portions of the area are overlain by alluvium. The Wilderness Study Area is within the Gold Butte mining district. Several gold mines with past production are nearby to the south of the Wilderness Study Area; one mine is reported in operation on a small scale. Several silver-bearing copper and zinc mines with past production are nearby to the east of the Wilderness Study Area

Jan 1, 1988

By G. St John Perrott

"The United States Bureau of Mines is cooperating with the State of Utah and the City of Salt Lake in an investigation of methods of abating the smoke nuisance in Salt Lake City. In the course of this work samples of the atmosphere have been collected and analyzed in an attempt to determine the part played by sulphur dioxide or smelter gases in polluting the air at Salt Lake City.A fairly wide-spread opinion exists in Salt Lake City that the smelters contribute appreciably to the smoke nuisance. The gases discharged from the smelter stacks are believed (1) to float over the city in a heavy blanket which prevents the smoke from rising, and (2) to unite with the water vapor in the air to form corrosive fogs injurious to health and property.The first of these theories seems untenable. If the gas did not mix with air it would sink, owing to its heavier specific gravity, and form a blanket an the earth. Actually, the gas diffuses rapidly in air and any part reaching Salt Take must he thoroughly diluted. Perhaps sulphur dioxide in sufficient concentration might aid in fog formation. The more obvious nuisance, however, would be the injury to health and vegetation.The Garfield smelter is 16 miles west of the city, The Murray smelter 8 miles south, and the Midvale smelter 12 miles south. Under normal operating conditions, a relatively small amount of solid matter is discharged from these stacks. The toxic gaseous constituent of the discharge is sulphur dioxide, it is being discharged from the smelters the year round. If they are a factor in the city's smoke problem, the concentration of this gas in the air of the city should be appreciable and should increase toward the smelters, the con centration being highest with a south or a west wind."

May 1, 1920

By Joseph Berman

The wolframite mineral series was studied to determine the effect of the FeO - MnO ratio on unit cell symmetry and thermal stability. This work was undertaken to evaluate the analytical procedures now in use for wolframite in scheelite and to aid in the development of improved methods of analysis. Wolframite grains were hand-picked, crushed, and screened; impurities were removed by selective magnetic separations using a Frantz isodynamic separator. The samples were further checked by optical spectroscopic and microscopic examination.

Jan 1, 1957

By John D. Sullivan

The recovery of copper by leaching from relatively low grade ores containing both oxidized and sulphide minerals is rapidly gaining in commercial importance. There is an economic limit below which certain ores can not be treated by concentration methods, and material with values below this limit must be discarded, possibly to be treated later, or the copper must be extracted by wet processes. Heap leaching has been carried out by the Phelps Dodge Corporation, Copper Queen Branch, for several years, and to-day its plant is a large producing unit. The Ohio Copper Coy at Bingham, Utah; has been leaching in place since 1919. Many other leaching operations are also being; carried out in various parts of the United States and in foreign countries. The plant at Rio Tinto, Spain, may be considered the father of heap leaching.

Jan 1, 1931

By G. R. Hopkins

The average quantity of heat needed to refine a barrel of crude oil in 1934 was 638,000 B.t.u., or about as much heat energy as contained in 5 gallons of fuel oil. Although the total heat utilized in 1934 was slightly above 1933, crude runs to stills increased 4 percent, hence the average requirement per barrel declined from 660,000 B.t.u. in 1933 to 638,000 B.t.u. in 1934 (see fig. 1). The average for 1934 constitutes a new record for firing efficiency, being just under the previous low of 1929. Heat consumption at refineries depends on many factors, of which the trends in yields of gasoline and lubricating oils are probably most important. The yield of gasoline is indicative of activity at cracking plants, which type of plant utilizes more than the average amount of heat per gallon of product. The yield of lubricating oils is indicative of the extent to which credo oil is refined; that is, it takes considerably more heat to refine a barrel of crude through lubricating oils than it does to separate only gasoline and kerosene. The yield of gasoline decreased from 43.7 percent in 1933 to 43.4 percent in 1934; on the other hand, the yield of gas oil and fuel oil increased. Although the yield of lubricating oils increased slightly in 1934 the theoretical increase in fuel requirements probably was offset by technical improvements, such as solvent refining.

Jan 1, 1935

By G. M. Martinez

A cell concept adaptable to large-scale electrowinning of zirconium metal from zirconium tetrachloride was investigated by the Federal Bureau of Mines. Tests were made in twin cells, each 12 inches in diameter by 33 inches long. Electrowinning was performed in one chamber from which the electrolyte was transferred after electrolysis to the other chamber where it was renewed by the introduction of ZrC14 by direct sublimation. The formation of a salt plug in the connecting pipe provided a seal between the chambers. Optimum electrolyte composition, with respect to quality of the metal product (91 pct meeting ASTM standards except for the oxygen content) and current-carrying capability (about 350 amp) was determined to be 16.7 wt-pct NaF-83.3 wt-pct NaCl mixture plus ZrC14 equal to about 3 wt-pct zirconium. A twin-cell design incorporating the unit operations covered by this investigation is proposed.

Jan 1, 1976

By Jr. Watts, B. K. Cantrell, D. H. Carlson, K. L. Rubow

"The use of diesel equipment in underground coal mines is controversial because ""whole diesel exhaust"" is regarded as ""a potential occupational carcinogen"" by the National Institute for Occupational Safety and Health (NIOSH). Threshold limit values (TLVs) are recommended for the gaseous pollutants; CO, CO2, NO, NO2, SO2, and some hydrocarbons emitted in diesel exhaust. There is, however, no TLV recommended for diesel exhaust aerosols (DEA) nor is there a standard method for sampling these aerosols.The University of Minnesota and the Bureau of Mines have collaborated to develop a personal diesel exhaust aerosol sampler (PDEAS) which utilizes size selective, inertial impaction and gravimetric analysis. During the field tests of this sampler, numerous air quality measurements were conducted in underground coal mines using diesel equipment. The objective of this report is to present these data and to assess the impact of diesel face haulage equipment on mine air quality.Air quality data were collected in four underground coal mines using continuous mining methods with diesel haulage equipment. Daily samples were collected at the section intake, haulageway, and on haulage vehicles. Both full-and partial-shift samples were collected using a variety of aerosol instruments, including the PDEAS and the micro-orifice, uniform deposit impactor (MOUDI) which sample the mine aerosol diesel exhaust fraction. Two of the mines were also monitored for the major gaseous constituents found in diesel exhaust CO, CO2, NO, NO2, and SO2. These measurements were made by either collecting bag samples for subsequent gas analysis or by Palmes dosimeters.The concentrations of CO, CO2, NO, NO2, and SO2, were well below regulated levels. The mine average DEA concentration determined by the PDEAS in the haulageway for the three mines surveyed using this instrument was 0.79 mg/m3, with a standard deviation of 0.19 mg/m3. DEA contributed 65% of the respirable aerosol, at this location. These results were the same as the mean DEA concentrations calculated from size distribution measurements obtained using the MOUDI. This was 0.78 mg/m3, with a standard deviation of 0.22 mg/m3."

Mar 1, 1992

By H. S. Auvil

[The shrinkage of coke after formation is one of the variables that effects the net expansion of the change in both industrial and test ovens. Various test results5/ have been interpreted as indicating that cokes from certain coals shrink to a marked extent and that other cokes show very little shrinkage; but no comprehensive experimental study of the shrinkage of coke after its formation and of the factors influencing this shrinkage has come to the attention of the authors.]

Jan 1, 1940

By E. J. Matson

The Table Mountain copper deposit is in an isolated portion of north-eastern Churchill County, Nev. Although copper-bearing outcrops have been known to exist in the area since 1909, no copper ore has been mined. Development of the property has been hampered by poor roads and rugged topography. Until 1941, the last 4 or 5 miles to the property had to be traveled either by foot or pack animal. As a part of the Bureau of Mines program of investigation and development of domestic mineral deposits, a project was started at the Table Mountain deposit. The Bureau began its field work on July 29, 1947, and completed it on October 18, 1948. Thirteen holes aggregating 2,711 linear feet, were drilled; samples were analyzed - 509 from cores and 143 from sludges. This report contains a brief history of the district and a description of the geology, deposits, and drilling done by the Bureau.

Jan 1, 1949

By J. R. Thoenen

[Before 1914 Germany held a virtual monopoly on the world supply of potash for fertilizer purposes. During the World War, potash shipments to the United States ceased, and recourse was had to domestic supplies. High war-tine prisms stimulated interest in various sources, and domestic production increased rapidly. At the close of the war, resumption of shipments from Germany mad other sources reduced prices to below pre-war levels, and, as a result, most of the domestic procedures ceased operations. This experience demonstrated that a domestic source of potash was necessary but that it must be of such a nature that it could compete in price with foreign sources. As a direct result the potash content of thick]

Jan 1, 1941

By G. W. Grove

Coal-mine officials and those who are preparing to become officials should be familiar with the instruments and devices that are employed rather commonly in and around mines and should know how to use them with safety and efficiency. Among these axe instruments and devices used in determining the pressure, velocity, volume, and certain other conditions of ventilation and in detecting the more common mine gases, such as methane, carbon monoxide, and hydrogen sulphide, or a deficiency of that very important agent, oxygen. Water gages, anemometers, barometers, psychrometers, flame safety lamps, lamp-testing boxes, and methane, carbon monoxide, and hydrogen sulphide detectors are described and their use and operation discussed in this paper.

Jan 1, 1938

By M. J. Kovalik

The effect of oxidation by air at temperatures ranging from 200° to 390° C on the change of chemical and physical properties of Pittsburgh-bed coal was studied as a function of processing time and temperature. The goal was to prepare a nonagglomerating fuel from a strongly coking coal for use in continuous carbonizing processes and in fixed-bed gasifiers. The oxidized coal was carbonized in a bench-scale apparatus, and the coke strength was evaluated in a Roga tumbler. Strength of the coke was progressively reduced with time of oxidation until the coking power of the coal was apparently destroyed. Time requirements to obtain an essentially nonagglomerating product were inversely related to processing temperature. Gaseous products released from the coal during oxidation reduced the yield of the desired nonagglomerating product, which decreased with time of oxidation at constant temperature and with increase in processing temperature at equal time. Oxidation at a temperature slightly above the lower limit of the plastic temperature range of Pittsburgh-bed coal was most effective because of the short processing time required and moderate processing losses.

Jan 1, 1963

By J. R. Thoenen

[Before 1914 Germany held virtual monopoly on the world supply of potash for fertilizer purposes. During the world War, potash shipments to the United States ceased, and recourse was had to domestic supplies. High war-time prices stimulated interest n various sources, and domestic production increased rapidly. At the close of the war, resumption of shipments from Germany and other sources reduced prices to below pre-war levels, and, as a result, most of the domestic producers ceased operational.]

Jan 1, 1941

By Fay B. Dillard

This Bureau of Mines report reviews the disposition of natural gas as delivered to industrial consumers via main line sales. Salient information on main line, or direct, natural gas sales to industrial users is presented by State) standard industrial classification code (SIC) revenue, and type of sales for the years 1968 through 1973.

Jan 1, 1975

By G. W. Elger

The Bureau of Mines investigated the conversion, at both laboratory and pilot plant scale, of a low-grade ilmenite to chlorination-grade feedstock that could substitute for imported rutile used to produce titanium tetrachloride. The concentrate was derived from the Tahawus, NY, lode deposit of ilmenite-magnetite in rock that contains anorthosite and gabbro. Charges of the ilmenite concentrate, containing 46.6 wt pct Ti02 blended with soda ash, were carbothermically reduced in an electric arc furnace, which separated most of the iron and left a high-titanium slag. However, the slag contained Ca, Mg, and Mn constituents that rendered the material unsuitable for continuous chlorination by causing plugging problems. After being ground and pelletized, the slag was reacted with S02 and air at 7000 to 9000 C, which selectively converted the harmful impurities to soluble compounds that were removed in a subsequent water or dilute HCI leach. In laboratory tests, the combined levels of harmful impurities were decreased from 5 to as low as 0.5 wt pct in leached slags. In pilot plant tests, leached slags sulfated at a rate of 10 lb/h averaged 85.5 wt pct Ti02 with pertinent impurity levels averaging 1.86 wt pct. The leached slag was successfully chlorinated in a laboratory fluidized-bed reactor at 9500 C to extract titanium as TiCI4.

Jan 1, 1986

By Roy E. Peterson

The Bureau of Mines conducted an investigation to produce metallized pellets from domestic iron ore superconcentrates using lignite and subbituminous coal as reductants. Feed materials for the metallizing process consisted of commercially indurated iron oxide pellets and green pellets prepared from upgraded domestic concentrates with graphite or limestone as internal additives. Durability of the green pellets during metallization was investigated in tests conducted in a 7-inch-ID rotating drum furnace. Test results indicated that the major cause of pellet disintegration with the concentrates used was the tumbling action during reduction rather than forces generated within the pellets. In larger scale tests made in a 34-inch-ID by 35-foot-long kiln, the previously indurated pellets were metallized with lignite at 1,030° C with little disintegration. A 96-percent level of metallization was obtained in pellets having an average compressive strength of 420 lb. In subsequent, similar tests using green pellets containing graphite or limestone, pellet disintegration was more severe, with 10 to 40 percent of the feed being lost as dust. The surviving pellets had metallizations ranging from 88.3 to 94.4 percent and compressive strengths ranging from 60 to 68 lb.

Jan 1, 1976

By D. E. Banks, J. K. H. Ma, Y. Rojanasakul, J. Y. C. Ma, C. J. Malanga

There is evidence to suggest that cell injury induced in alveolar macrophages (AM) following phagocytic activation by silica particles may be mediated through changes in intracellular free calcium [Ca 2+}. However, the mechanism of silicainduced cytotoxicity relative to [Ca2+], overloading is not yet clear. To provide a better insight into this mechanism, isolated rat AMs were exposed to varying concentrations of crystalline silica (particle size< 5 µm in diameter) and the fluctuation in their [Ca2+]; and cell integrity were quantitatively monitored with the fluorescent calcium probe, Fura-2 AM, and the membrane integrity indicator, propidium iodide (Pl). Results from this study indicate that silica can rapidly increase [Ca2+]; in a dose-dependent manner with a characteristic transient calcium rise at low doses (<0.1 mg/ml) and an elevated and sustained rise at high doses (>0.1 mg/ml). Depletion of extracellular calcium [Ca 2+]0 markedly inhibited the [Ca2+]; rise (˜90%), suggesting that Ca2+ influx from extracellular source is a major mechanism for silica-induced [Ca2+]; rise. When used at low doses but sufficient to cause a transient [Ca2+]; rise, silica did not cause significant increase in cellular Pl uptake during the time of study, suggesting the presevation of membrane integrity of AMs under these conditions. At high doses of silica, however, a marked increase in Pl nuclear fluorescence was observed. Depletion of [Ca 2+] 0 greatly inhibited cellular Pl uptake, induced by 0. 1 mg/ml or higher doses of silica. This suggests that Ca 2 + influx, as a result of silica activation, is associated with cell injury. Indeed, our results further demonstrated that the low dose effect of silica on Ca 2+ influx is inhibited by the Ca2+ channel blocker nifedipine. At high doses of silica (>0.1 mg/ml), cell injury was not prevented by nifedipine or extracellular Ca2+ depletion, suggesting that other cytotoxic mechanisms, i.e., nonspecific membrane damage due to lipid peroxidation, are also responsible for the silica-induced cell injury. Silica had no significant effect on cellular ATP content during the time course of the study, indicating that the observed silicainduced (Ca2 ... ); rise was not due to the impairment of Ca2 + -ATPase pumps, which restricts Ca2+ efflux. Pretreatment of the cells with cytochalasin B to block phagocytosis failed to prevent the effect of silica on [Ca2+]; rise. Taken together, these results suggest that the elevation of [Ca2+]; caused by silica is due mainly to Ca2+ influx through plasma membrane Ca2+,channels and nonspecific membrane damage (at high doses). Neither ATP depletion nor Ca2+ leakage during phagocytosis was attributed to the silica-induced [Ca2+]; rise.

Nov 1, 1995

By PALMER LARSEN

INDEX TO GEOPHYSICAL ABSTRACTS

May 1, 1931

By PHILIP A. ZANG

The rapidly increasing use of motor vehicles in the United States has introduced an entirely new problem in the proper ventilation oftunnels , subways , and other confined spaces through which such machines must pass . This problem was brought to the attention of the Bureau of Mines by the New York and New Jersey State Bridge and Tunnel Commissions with reference to the ventilation of the proposed vehicular tunnel under the Hudson River . This tunnel , consisting of twin tubes 29 feet in diameter and 8500 feet long between entrance and exit , presented an unprecedented problem in ventilation both on account of its length and on account of the traffic density , which is expected to reach a maximum of 1900 vehicles per hour . An exhaustive study by the tunnel engineers of all available data on the amount and composition of automobile exhaust gas disclosed very little information on the percentage of carbon monoxide in motor exhaust gas from the average run of automobiles and trucks under actual operating conditions on the road. It was well known that carburetor adjustment and other operating factors changed the percentage of the poisonous constituent , carbon monoxide , from practically 0 to 12 or 13 per cent ; but no safe estimate could be made of the most probable figure without further investigation .

Mar 1, 1921