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By Van E. Shaw

Three comparatively simple, efficient, and rapid extraction methods for the dissolution of yttrium and rare-earth elements from a euxenite carbonate residue have been developed, using dilute sulfuric acid as the solvent. Extraction processes have resulted in yields of 98+ percent of the total rare-earth elements and yttrium contained in the residue and have given preliminary separation between the cerium-group and the yttrium-group rare-earth elements. Extraction procedures presented are: Procedure 1. -The recovery of total rare-earth elements and yttrium by a cold dilute sulfuric acid leach at a pH of 2.5. Procedure 2. -The recovery of yttrium and yttrium-group rare-earth elements by leaching with dilute sulfuric acid at 125° F. and a pH of 3.0, with subsequent recovery of the cerium-group rare-earth elements by a cold dilute sulfuric acid leach of the residue at a pH of 2.5. Procedure 3. -The recovery of the total rare-earth elements and yttrium by fractional leaching as in procedure 1, followed by boiling the sulfate solution, which precipitates the cerium-group rare-earth elements and leaves the yttrium-group rare-earth elements in solution.

Jan 1, 1959

By H. M. Smith

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Jan 1, 1927

By Charles White Merrill

Silver consumption in the arts and industries of the United States during 1930 and 1931 has remained remarkably near the high level established in 1929. Undoubtedly the sharp drop in the price of silver has been an important factor in supporting consumption, but silver's peculiar properties and uses probably have been an even more compelling reason for its sustained utilization. In its most important use - sterling silverware - it seemingly has most serious competition, but well established tradition protects the demand for sterling ware and the law forbids the term "sterling" to be applied to any material not containing at least 92.5 per cent silver. The photographic industry is dependent upon properties of certain silver salts possessed by no other material. Consequently silver is indispensable to all photography, including the huge motion picture industry. Other uses for silver could be listed which, because of special features, likewise have tended to maintain the consumption of silver in the arts and industries of the United States. The figures which this report makes available for the first time are the detailed silver consumption figures for the arts and industries of the United States for 1930 and 1931. These figures have been tabulated with the previously published(3) figures for 1928 and 1929 thus presenting a 4-year statistical record of silver consumption. All quantities are given in troy ounces, 1,000 fine.

Jan 1, 1932

By A. E. Harak

To determine the retorting characteristics of a column of mine-run, ungraded oil shale ranging in size from fines to pieces weighing as much as 5 tons, a 150-ton batch retort was designed and constructed at the Laramie Energy Research Center, Laramie, Wyo. The retort vessel is 45 feet high by 11-1/2 feel in inside diameter and is supported in a 92-Foot-high steel superstructure. Mine-run shale from the Bureau of Mines facility near Rifle, Colo., assaying about 25 gallons of oil per ton, is currently being used as the test shale. To date, three runs have been completed. Results of the second and third runs are reported in this paper. The two runs considered in this report are the first of a series of nine to determine operating conditions that will yield maximum oil recovery from a column of mine-run shale. Variables studied :ire the oxygen content of the retorting gas and the space velocity of the retorting gas expressed as ft3 gas/ft3 bed/min. Oil recoveries for the two runs reported are 62.2 volume percent of Fischer assay for the run using higher oxygen and space velocity, compared with 39.3 volume-percent when less oxygen and a Lower space velocity were used.

Jan 1, 1971

By F. S. Crawford

It has been said that safety promotion passes through four stages--the band-playing, the machine-guarding, the protective equipment, and finally the educational stage; the last is the most important in the development of the safety program. It has been estimated that only 15 percent of accidents can be pre- vented by machine guarding and protective equipment; the other 85 percent must be stopped by the safety efforts of the individual workers and their supervisory officials, and one of the fundamentals of safety work is the education of workers to develop safety consciousness or safety mindedness. One way of educating men to think about safety is by the use of posters. Safety engineers at the Calumet 2 Hecla mines in Michigan have been conduct- ing a safety contest among the men by the use of posters of an unusual type in addition to those usually employed to illustrate bad practices and to display the number of days without a lost-time accident. The first requisite for the success of the safety poster is a good artist or draftsman; in the poster contest instituted at the Calumet & Hecla mines two sheets were prepared illustrating various conditions in the slope workings, including a large number of unsafe practices. The object of the contest was to get the men to think about safety through criticism of the unsafe conditions displayed on the posters. The following notice accom- panied the posters:

Feb 1, 1935

Viable domestic mineral industries are essential to the economic health of the United States and the well-being of its citizens. The charts in this publication reflect developments significant to the Nation's mineral industries during 1975. Last year was a year of reduced activity for the Nation's mineral industries. Although the value of the country's total mineral output rose, for example, the overall production and use of many minerals fell. At the same time, the industry experienced lower profits and higher debt/equity ratios. These and other adverse effects on many segments of the Nation's mineral industries resulted from the overall decline in domestic and international economic activity.

Jan 1, 1976

By Hamid N. Maleki

Cooperative efforts by the Bureau of Mines and Agapito & Associates, Inc., Grand Junction, CO, achieved the research objective of showing that data from measurements of the rate and change in rate of mine roof movement can be effective in detecting roof instability. Several instruments and techniques have been used to monitor roof movement and to detect imminent roof caves during pillar robbing. Early detection of unstable conditions can provide time either to withdraw personnel and equipment or to allocate supplemental support to prevent injury or down-time. Critical convergence rates were determined both manually and electronically. The detection of critical rate of movement has been shown to be an effective tool in ground control efforts.

Jan 1, 1988

By R. Karl Zipf, Z. T. Bieniawski

"A set of fracture profile photomicrographs is presented for fractures generated under mixed mode loading of the Pittsburgh coal. The fractal dimension is used· to characterize the irregularity of these profiles and a tentative relationship is presented between the fractal dimension and the fracture toughness. Surface roughness appears to depend solely on the stress intensity and no other dependence was observed with fracture loading mode, loading rate· or specimen orientation. Observations of crack bifurcations.in fracture profiles can indicate crack growth direction whereas direct surface observations generally cannot in materials such as rock and coal.1 INTRODUCTIONThe production of fine fragments of material as a result of some loading event occurs in many industrial processes. In crushing and grinding, the efficient production of fine fragments is the desired end result; .however, in coal cutting, the production of fine fragments may lead to high levels of respirable dust in the immediate atmosphere with the danger of human lung diseases. Two of the most important sources of fragments in the 1 to 10 micron size range during a cutting process are 1) severe crushing in a zone near the loading tool and 2) subsequent shearing along major crack surfaces that form the larger fragments during material reduction. These and other sources of fine fragments generation are discussed by Roepke (1984) and Zipf and Bieniawski (1986). The physical character of the nearly created major crack surfaces is believed to have a strong influence on the amount of fine fragment generation that occurs during subsequent shearing movement. When the major large fragments initially form, they are ""locked"" in place by the irregular character of the new fracture surface. Only after some relative motion has occurred between fragments are they actually liberated, and the net result is the formation of additional fine fragments. The fine fragmentation is not necessarily limited to the shearing of high points from the macrocrack surf ace since material remaining in the wake of the crack tip is damaged to a substantial depth below the actual crack surface."

Aug 31, 1989

By William J. Wuest

The technical analysis of parameters that can influence roof and rib reinforcement is important to the operation of safe and profitable underground mines. One such parameter, studied in this U.S. Bureau of Mines investigation, is the effect of time on untensioned, resin-grouted bolt anchorage characteristics. A group of seventy-three 4-ft-long bolts with three different grout column lengths were I installed in a stable coal mine roof. The bolts were then subjected to standardized pull tests at various intervals throughout a 37-month period. For each test, load-deformation data were reduced to determine axial stiffness and yield point. The magnitudes of these two anchorage characteristics at the time of installation were compared with results from subsequent pull tests to determine if anchorage capacity deteriorated. Bolts with 18-in grout columns were studied over 9 months, and no measurable loss occurred. Bolts with 48-and 24-in grout columns were studied over 37 months and also exhibited no measurable loss.

Jan 1, 2010

By E. D. Gardner

This paper is one of a series on milling methods being published by the United States Bureau of Mines. Atlanta is in Elmore County, Idaho, about 80 miles from the railroad at Mountain Home, Idaho. The concentrator is at an elevation of, 6,000 feet and located in a timbered, well-watered region of relatively heavy snowfall. The snow, however, does not seriously affect local operations. The track road to Mountain Home, which passes over a mountain range, is closed each winter from about November 1 to June 15. During this period concentrates are stored and bullion is shipped by airplane. Power is generated by a Diesel engine and by an auxiliary hydroelectric plant. Gold is the principal metal produced; the or also contains an able quantity of silver.

Jan 1, 1935

By A. B. Clayton

The Bumpus Cove area is in Unicoi County, Tenn., about 9 miles south of Jonesboro and 5 miles northwest of Erwin. Iron and lead ores were mined in the Bumpus Cove area before the American Revolution. The production of those metals continued intermittently until 1916. In 1850 this area was the most important producer of iron in the South. In 1911 several carloads of zinc ore was recovered from old dumps and shipped to Missouri smelters. In 1913 systematic mining of zinc ores was begun and continued until 1916. After that year, mining again became sporadic and continued so until discontinued in 1943.

Jan 1, 1949

By Robert J. Evans

The Hopper-Feeder-Bolter (HFB) is a prototype multifunctional machine designed to improve productivity by minimizing continuous miner place changes. It is designed primarily to work beside a two-pass continuous miner, bolting on one side and then place changing to bolt the other side while simultaneously providing a surge car and lump breaker located directly behind the continuous miner. Surface testing was conducted at the Bureau of Mines Mine Equipment Test Facility (METF) to evaluate overall system performance and reliability. Tests were conducted to evaluate place changing, tramming, lump breaking, roof bolting, drawbar pull, conveying, temporary roof-support (TRS) capacity, lighting, and noise. Surface test results indicate the HFB is ready to be tested and evaluated underground in a production mode.

Jan 1, 1988

By Wilbert J. Huff

The Explosives Division of the United States Bureau of Mines makes certain laboratory and field investigations that deal with explosions, explosives, ignition, and combustion, together with many related problems, such as the cause and prevention of fires, and certain fundamental scientific questions bearing upon the determination of the chemical and physical mechanisms underlying some of the important phenomena encountered. Its work on explosives has been particularly directed toward determination of the chemical and physical characteristics of explosives designed for use in coal mines and in a more limited way to those used in metal mines, tunnels, quarries, and other engineering operations. This testing is handled by two units of the Explosives Division, as follows:

Jan 1, 1937

By D. A. Reynolds

The Bureau of Mines-American Gas Association survey of the carbonizing properties of American coals was begun in 1929, and has been continued almost without interruption since that time. Upwards of 100 coals have been carbonized at low, medium, and high temperatures in this survey, and about 200 additional coals have been carbonized at high temperatures only. All survey coals were blended with coal of different rank for carbonization at one high temperature (900° C,). During the past few years, 12-high-volatile A coals were blended with Pocahontas No 3 coal from Kimball, McDowell County, W. Va., and in this report the physical properties of the cokes from these high-volatile coals and their blends are compared.

Jan 1, 1949

By G. B. Gait

This report is the fifth in a series concerning the Bureau of Mines program for microfilming maps of abandoned mines in the Pennsylvania anthracite region. A catalog of the microfilmed maps of 47 of 49 major mines and 18 independent mines in the Southern field is presented. Previous reports included catalogs of microfilmed maps of mines in the Eastern Middle field, the Wyoming and Lackawanna Basins of the Northern field, and the Western Middle anthracite field.

Jan 1, 1978

By Thomas L. McVay

Laboratory batch and pilot plant flotation tests were made to determine the feasibility of recovering commercial grade kyanite from a quartzite- kyanite rock from the Graves Mountain, Ga., deposit. Best results in laboratory and continuous tests were obtained using sodium carbonate for pH control, citric acid for quartz depression, and oleic acid as the kyanite collector. Over 80 percent of the kyanite was recovered in a concentrate analyzing 56.8 percent Al203 and 3.8 percent hydrochloric acid soluble Fe203. Subsequent treatment of the flotation concentrate by magnetic separation reduced the acid soluble Fe2O3 to 0.6 percent and increased the alumina content to 59.2 percent. Acid leaching of the concentrate gave a product analyzing 59.7 percent Al203 and about 0.1 percent Fe203. As a result of the beneficiation research, a commercial kyanite flotation plant was completed in September 1962 by private industry.

Jan 1, 1963

By Michael S. Miller

In 1986 and 1987, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 550-acre Carson-Iceberg Wilderness Study Area (NV-030-532), in order to evaluate its identified mineral resources. The Wilderness Study Area is located in Alpine County, CA, 11 mi southeast of Markleeville, CA. Tertiary volcanic and granitic rocks, as well as alluvium, underlie the area. Hydrothermal alteration and faulting have affected some rocks; argillic, silicic, and limonitic alteration are found, particularly near faults. No mineral resources were identified in the Wilderness Study Area. The area has one small pit and no mines or claims. Samples from the Wilderness Study Area and vicinity contained uneconomic amounts of gold, silver, copper, lead, zinc, mercury, arsenic, and molybdenum. Mineral occurrences are too small and low grade to be of interest within the foreseeable future.

Jan 1, 1988

By M. E. Volin

The Buckeye manganese deposits are in Stanislaus County, Calif., about 33 miles south of Tracy. From 1917 to 1919 the deposits produced 13,370 tons of ore reported to average 46 percent manganese and 14 percent silica. The deposits are confined to two areas of' development, known as the north mine workings and the south mine workings, about 700 feet apart horizontally. Mineralization occurs chiefly as rhodochrosite and psilomelane interbedded in cherts of the Franciscan formation. As a part of the Bureau of Mines program of investigation and development of domestic mineral deposits, a development project was started November 25, 1940, and completed June 27, 1941. The Federal Geological Survey cooperated by mapping the topography and geology and logging the drill cores. The program included road and. trail building, trenching, underground excavation, diamond drilling, and sampling. The following pages mention the location, brief the history, and note the physical .features of' the district. Mine workings are sketched, the deposit is described, and the plan of the project is noted. The work performed by the Bureau of Mines is explained in the concluding pages with a summary of the drill-hole logs.

Jan 1, 1949

By William H. King

Preliminary examination of the Virgin River manganese deposit was made by C. H. Johnson, Bureau of Mines engineer, in March 1941. During, April and May 8 trenches were dug, a 48-foot inclined shaft was sunk, and 719 linear feet of channel samples were cut. McKelvey and Wiese, of the Federal Geological Survey, completed mapping the deposit, including the entire area of overlying formations comprising the point of land between the outcrop and Lake Mead. The geologic maps, maps, and ore estimates resulting from these examinations formed the basis for a preliminary report by C. H. Johnson, who recommended further exploration by diamond drilling.

Jan 1, 1949

By H. R. Babitzke, H. Kato, R. E. Siemens

An investigation was made to provide further information for evaluating columbium- hafnium alloys for use as high - temperature structural materials . The columbium- hafnium system was investigated between 700 ° and 2,400 ° C by melting point , thermal analysis , X - ray diffraction , electrical resistivity , and metallographic techniques . The equilibrium diagram is the beta isomorphous type , with columbium tending to stabilize the beta phase . Addition of 60 atomic percent columbium stabilizes the beta phase at 700 ° C. The allotropic transformation temperature of hafnium is 1,750 ° ± 20 ° C. A minimum melting point occurs near 75 atomic percent hafnium .

Jan 1, 1964