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By Louis C. Brichta

The Rush Creek district of Marion County, Ark., has had a more or less continuous record of zinc production over the past 40 years. The ore has come from many small mines working on oxidized and semi-oxidized deposits found in the Everton formation where that formation forms the present surface rock. Prospecting has been restricted to the hillsides above the creek levels, the actual ore outcrops being the guides. Little attention has been paid the possible sulfide zones. In August 1942, the United States Geological Survey and the Bureau of Mines recommended exploration of the Powell and Cotter formations, which underlie the Everton, for which purpose the Survey had previously located 18 proposed drill-hole sites in geological structures that seemed favorable to are deposition.

Jan 1, 1949

By Foster Fraas

A comparison has been made between cubes and spheres in the matrix of the high-intensity wet magnetic separator. For two inclined plane surfaces, such as may occur with cubes, the maximum force value, H [dH-dx] is at the point of nearest approach and is much higher than the force resulting from adjacent spheres. Although the maximum force value for cubes is higher, it decreases more rapidly at increasing distances. The maximum force for spheres is at an appreciable distance from the point of nearest approach. At field intensities for magnetic saturation of the iron spheres, the force extends to further distances with greater uniformity approximating that of the constant force or isodynamic field. The force is also independent of the sphere diameter, which permits the scaling of the sphere diameter to provide changes in particle migration distances without changes in force gradient.

Jan 1, 1972

By W. E. Wells

This report describes experimental investigations made in the batchwise retorting of Colorado oil shale. Three heat-carrying mediums were used -hot shale gas, superheated steam, and hot flue gas. Using hot Shale gas for retorting, the several variables studied were retort-inlet-gas temperature, gas velocity through the shale bed, shale particle size, and grade of shale. In studying the effect of any one of these variables on oil yield, as and operability, the other variables were maintained essentially constant. Oil yields decreased with increasing in-let-gas temperature and increasing shale-particle size, and oil yield increased with increasing grade of Shale up to 50 gallons of oil per ton of shale, beyond which the process was inoperable because of swelling and caking of the shale during retorting. Changes in gas velocity had little effect on oil yield. Gas yield increased with increasing inlet-gas temperature, gas velocity, particle size, and shale grade. Oil yields of 100 percent of Fischer assay and from 1,600 to 1,800 cubic feet of 300-B.t.u. gas per ton of shale were obtained. Two runs only were made using superheated steam. Oil yields averaged 97 percent of Fischer assay, and gas yields averaged 4,00o cubic feet per ton of shale. Retorting with a hot flue gas produced from combustion in the shale bed, as in the N-T-U process, gave excellent yields using closely sized shale with recycling of flue gas. An excess of fine shale in the charge resulted in channeling and low oil yields. Using no recycle gas, good yields were obtained that tended to decrease with increasing air rate, and the retorting rate increased with increasing air rate over the range studied. Coking was not found serious with 30-gallon shale at the air rates used.

Jan 1, 1952

Illinois has the largest reported bituminous coal resources of any state and is one of largest coal-producing states in the nation. Coal-bearing rocks underlie about 65 percent of Illinois, including all or part of 86 of its 102 counties. An estimated 18 1 billion tons of coal resources are still in the ground. Using present mining methods, more than 30 billion tons of coal are classified as recoverable. This represents almost one-eighth of the total recoverable reserves of all types of coal in the United States. The state's surface mining regulatory program was conditionally approved June 1,1982. It received full approval October 25,1988. The Abandoned Mine Land Program was approved June 1, 1982, and the AML emergency authority June 11, 1984.

Jan 1, 1992

By John R. Troxell

"INTRODUCTION Lookout Mountain is the natural barmier that isolates Dade County from the rest of Georgia. Legend has it that Dade County seceded from the Union long before the rest of the State of Georgia and did not officially return until July 4, 1945.Coal mining began in the Lookout Mountain area in 1891, and by 1894 production amounted to about 1,000 tons daily. Present production by the two principal operating companies is about 3,600 tons monthly.In the Sand Mountain area, coal has been mined intermittently since before the Civil War, and probably 6,500,000 tons has been produced.The Bureau of Mines coal project was initiated to alleviate a possible coal shortage and to assist the State in developing coal deposits to supply State institutions and local markets. Drilling began January 1, 1945, and ended May 11, 1945, after 2,907 feet had been drilled. By this time the Georgia Power Co. became interested in northwest Georgia coal fields as a possible source of more economic fuel for their steam-driven power plants, but the Bureau continued to act in an advisory capacity to the power company until June 30, 1945."

Oct 1, 1946

By A. B. Hooker, J. W. Paul

"There was a time when any suggestion that the Davy flame (safety) lamp be discarded, would have evoked unlimited, criticism. However, that time is past.Investigations both here and abroad have shown conclusively that the Davy lamp does not have the necessary factor of safety against ignitions of mine gas, and England, the lost stronghold of the Davy lamp in Europe, has eliminated this lamp and substituted safer types.In the United States there are companies who still use the Davy lamp in spite of all that has been said and published as to the dangers connected with its use.Recently the purchasing agent of an anthracite coal company requested the Department of the Interior, Bureau of Mines, to pass upon the safety of some braise gauzes for use in a shielded Davy lamp. A shielded Davy lamp is an ordinary Davy safety lamp equipped with a circular brass shield that is attached to the lamp posts. This shield extends about one-half way around the gauze and one-half of the gauze height. The main purpose of the shield is to prevent the lamps being extinguished by a sudden increase in the velocity of the air current past the lamp.The brass gauzes submitted for this test represented two grades of brass - a yellow brass and a red brass. The analysis of these brasses was not determined. Two shielded Davy lamps that were submitted for the tests each had a steel gauze. These steel gauzes were also tested. Tests were made in horizontally moving mixtures of Pittsburgh natural gas and air at velocities of 400 to 1,000 feet per minute. The gas percentages used were 7%, 8.6%, and 11%. Tests were made with the lamp shield in two positions relative to the lamp and direction of flow of the gas-and-air mixture. In one position the shield was between the gauze and flow, as normally used. In the other position the shield was on the downstream side of the lamp. The tests were continued until one or more failures or gas explosions been obtained with each of the six gauzes. The results of these tests summarized as follows:"

Jun 1, 1923

By C. E. Brechtel

This project describes the design and testing of large face ventilation systems for oil shale mining. A design data base was generated by reviewing general industry practice, oil shale industry planning, and technical literature. Conceptual designs for seven different systems were developed and evaluated for suitability. A large, free-standing, jet fan and reversible fan with rigid duct were selected for fabrication and testing. The two systems were field tested in a dead-end heading 55 ft wide by 30 ft high and 320 ft long. System performance was optimized using measurements of air flow direction and air velocity. Total system performance was then measured using SF6 tracer gas released to simulate blast fumes, hot diesel exhaust, methane layering and methane from a blasted muckpile. Field testing indicated that both systems delivered similar performance. The jet fan offered some clear advantages because of its mobility, ease of oper-ation and lower power requirement. It also offered some functional advantages in ventilating for methane because of it high average velocity.

Jan 1, 1985

By R. W. Freedman

The gas chromatographic method, devised by the Bureau of Mines for analyzing routine mine air samples, was compared with the infrared method used for confirmatory determination of methane in mine air. While maintaining the specificity of the infrared method for methane determination, the gas chromatographic method is more precise, much more rapidly performed, and more convenient.

Jan 1, 1968

By O. C. Blade

A comparison of certain properties of the commercial aviation gasolines produced in the United States during October 1949, 1950, and 1951 is presented in table 1, the 1951 data being average values from tables 3 through 6 of the present report. Trends in the average values of certain characteristics of these fuels may be seen in figures 1 through 4 which also indicate the minimum and maximum values. As may be observed, with the exception of changes in kinematic viscosities, the properties of commercial aviation gasolines have not varied greatly during recent years. A list of aviation-gasoline survey reports published by the Bureau of Mines is given on page 6. A summary of the average values of the properties on jet fuels is shown in table 2.

Jan 1, 1952

By J. S. McNabb

"A search for manganese ore by core-drill exploration was carried out by the Bureau of Mines in the Philipsburg mining district in Granite County, Mont., in 1939 and 1940. This work was based on detailed studies of the manganese ore bodies of the district previously made by the Geological Survey.In 1949 further search for manganese in the district was deemed advisable. Diamond drilling was begun the following year as a joint program by the Geological Survey and the Bureau of Mines with the primary purposes of probing ore-leasing structures and extending the limits of known ore bodies. A secondary objective was to test a geologic theory based on a new conception of manganese-ore localization. The exploration targets were designated and the drilling results interpreted by the Geological Survey, and the Bureau of Mines was responsible for the drilling, sampling, and core handling. Improved drilling equipment and methods were utilized in an effort to obtain better core recoveries than resulted from the earlier drilling campaign.The Philipsburg mining district, Granite County, Mont., is 27 miles south of Drurrnnond, about 45 miles airline northwest of Butte, and 1 mile east of Philipsburg. During the course of the investigation patented lode-mining claims owned by the American Machine & Metals, Inc., the Contact Mines, Inc., and the Moorlight Mining Co. were diamond drilled.The district has been an important source of domestic manganese dioxide ore since local recognition of the mineral's importance during World War I. Peak annual output in 1918 of about 127,000 tons of manganese ore was utilized principally by the steel industry. A small but relatively steady output has persisted to the present to satisfy demands by battery manufacturers for battery-grade manganese dioxide.The known manganese deposits of the district are in sedimentary rocks of Paleozoic age. These rocks lie along a north-trending anticline traversed by a series of east-west tension veins. The east flank of the anticline terminates at a steep-dipping fault contact against a small granodiorite batholith.Replacement deposits of manganese oxides and carbonates occur locally in or closely associated with tension veins cutting calcareous rocks, or adjacent to the intrusive. Rhodochrosite has been a common accessory mineral in deposits valuable chiefly for lead, zinc, and silver. Some of the replacement deposits characteristically are irr2gular in outline, whereas others have fairly regular walls marking the limits of favorable beds."

Dec 1, 1955

Possible consequences of continuing internal political unrest and the imposition of foreign sanctions raise concerns about the traditional reliability of the Republic of South Africa as a major world supplier of important minerals. A recent Bureau of Mines' technical report (Open File Report 76-86) examined the impacts of temporary peacetime disruption scenarios for six key materials and mitigating options. Because of South Africa's dominant producer position for these minerals (except for cobalt), expansion of primary production capacity outside of South Africa is not a short term mitigative option. However, prospects of a longer term disruption would likely spur investment in capacity expansion in alternative Market Economy Country supply sources. This report identifies the resources, production costs, and burdens that would be placed on alternative MEC producers of chromium, cobalt, gold, manganese, and platinum-group minerals if South Africa's production were subject to a long term; disruption. When long term supplies from South African deposits are discounted, more than a few years reserves were found only for cobalt and manganese. Even for these two minerals, higher sustained prices would be required to increase manganese production capacity and to support means of cobalt transportation not through South Africa.

Jan 1, 1986

By Robert E. Barieau

This report gives the principles of the method used by the Helium Research Center of the Bureau of Mines when solving nonlinear-regression problems and contains the mathematical equations necessary to accomplish the following objectives: the evaluation of the parameters in such a way that the sum of the weighted squares of the residuals of an experimental observable is a true minimum, regardless of the functional relationship between the variables and these parameters; and the evaluation of all variances and covariances of the parameters by means of the usual approximation of the law for the propagation of errors.

Jan 1, 1967

By Wesley Holmes

Concentrating, nodulizing, and smelting studies were conducted at the Albany Metallurgy Research Center of the Bureau of Mines to determine whether (1) western iron ores of the type found in the Carter Greek deposit near Dillon, Mont., could be utilized; (2) concentrates of acceptable grade with good iron recovery could be attained by wet-magnetic beneficiation; (3) nodulized concentrates could be smelted with reductants readily available in Montana; (4) iron concentrates could be smelted without prior agglomeration; and (5) high-purity iron could be produced directly from high-grade concentrates, Three small samples and two tonnage samples from the Carter Creek deposit were uniform in chemical composition, and their iron content averaged about 31 percent. They were found to be banded gneisses, and magnetite was the principal iron-bearing mineral.

Jan 1, 1962

By Jerry W. Ramsey

The Bureau of Mines examined a low-, a medium-, and a high-volatile Pennsylvania anthracite by densimetric methods using four mesh si.s of each anthracite. Using high-pressure mercury the macropore volumes and distributions of these pore volumes determined, densities in mercury were calculated, and specific pore vo1.r. ware obtained from these mercury densities in conjunction with helium densities. The helium densities were also used with the ultimate analyses of these anthracites in calculating structural parameters by statistical densimetric methods. The effect of 106 or 108 rads of gamma irradiation in the presence of air and in vacuum upon the properties studied with two mesh sizes of each anthracite. Results of the statistical densimetric method seem to show some breakdown of condensed ring structural units at the lower irradiation level, with subsequent polymerization at the longer period of gamma irradiation. The structural parameters obtained also indicated that in going from high- to low-volatile anthracite, either the number of condensed rings per structural unit increased, or the degree of polymerization increased.

Jan 1, 1965

This paper on. the physical and chemical properties of crude oils from California fields is one of a series of reports on the oil-producing districts of the United States., The paper includes a short discussion of results, tabular data, and individual analyses of eight California crudes. Analyses of other crude oils from California have been published in Reports, of Investigations 2595,3/ 2608,4/ and 28465/. The samples were obtained by members of the San Francisco office of the Bureau of Mines. The collecting samples was facilitated by the courtesy of representatives of oil companies in California.

Jan 1, 1931

By John E. Kelley

The Bureau of Mines conducted a study to determine the feasibility of joining refractory metal compounds to each other and to oxide ceramics by a vacuum hot press-diffusion bonding method. Very satisfactory joins were made of ZrC to ZrB2, ZrN to ZrB2, ZrC to ZrN, and of ZrC, ZrN, and ZrB2 to Al203. Each of these join assemblies contained a mixture layer comprising 50 weight-percent each of the two end compounds. The mixture layer, sandwiched between each end compound, enhanced bonding and smoothed out the thermal expansion gradient between the two end members. Strength and thermal shock tests showed that the join areas of the ZrC, ZrN, and ZrB2 joins were stronger and more shock resistant than the parent materials. Also included in the joining tests was one each of TiC to TiB2, TiC to TiN, TiB2 to TIN, and TiC to ZrB2 joins. Each of these was well bonded, showing that the vacuum-hot-press method can be used for a variety of systems.

Jan 1, 1969

By A. N. Fried

One of the important problems confronting oil producers in appraising the possibilities of secondary recovery in many California fields is the effect of viscosity on oil recovery by water flooding. In January 1954 there were 554 fields and/or pools, in the State, that produced 1 million barrels daily, and 138 of these pools produced approximately 267 thousand barrels daily of heavy crude oil having gravities below 200 API. Many of these fields are nearing the end of their primary economic life and still have high residual-oil saturations, a favorable factor in water flooding. The crux of the problem is whether or not enough oil can be recovered from these fields by water flooding to make the operation economically successful. Some experiments on the relationship between viscosity and oil recovery have been made by other investigators, but in most instances the viscosity of the oils used in the experiments was lower than the viscosity of the oils found in many of the heavy-oil fields in California. A study was undertaken, therefore, to determine the relationship between oil viscosity and recovery over a wider range of viscosities and to compare the experimental results with those predicted by theoretical calculations.

Jan 1, 1955

By L. C. IlsLey

Through the cooperation of the Pennsylvania Department of Mines the writer obtained from State, records detailed information concerning coal-mine accidents occurring in Pennsylvania bituminous mines during 1939, particularly those nonfatal accidents in which the injured person lost 60 or more days? time from mark. The writer wishes to acknowledge assistance received from Pennsylvania State officials, especially Richard Maize, secretary of mines, and. Joseph J, Walsh, deputy secretary of mines; also to Thomas Dickinson,3/ of the Bureau of Mines, who rendered valuable assistance in assembling the data an the several tables.

Jan 1, 1941

By M. J. Waller

Surface resistivity techniques were used at four field sites to monitor changes in apparent resistivities with variations in soil moisture content in the vadose zone. Apparent resistivity values were correlated with gravimetric moisture contents from soil samples taken at each site. Tensiometer readings were taken at two sites and correlated with the results of gravimetric moisture contents and apparent resistivities. Moisture at two of the sites was added by extensive watering; rainfall events were monitored at the other two sites. A recharge event at a dewatering program was monitored at a fifth site. A Ghosh-Koefed multi-layer computing algorithm was used to derive true resistivities from bulk or apparent resistivities. An automated data acquisition system was developed to measure resistivity changes and to process the data in the field. These studies are the first to evaluate measurement of moisture migration in clay rich soils using surface resistivity techniques. Results indicate that surface resistivity techniques readily measure changes in moisture contents in the vadose zone in clay rich soils. Correlation of apparent and true resistivity values with gravimetric moisture contents is more complex and requires additional research.

Jan 1, 1986

By T. F. Mitchell

As a part of the program of investigation of domestic sources of manganese ore, mining engineers of the Bureau of Mines examined and obtained samples of ore from two properties in the vicinity of Bettie Mountain, Lander County, Nev. In addition, samples from three claims in the Carico Lake region, Lander County, Nev., were submitted by private interests. RS the ores were too low in grade to be acceptable for the direct production of ferromanganese, their amenability to concentration by ore dressing was investigated. The Black Bock property is 16 miles south of Valmy, Nev., and is owned by Western Alloys, Inc., Salt Lake City, Utah. The deposit is a replacement of sedimentary rock by manganese oxides. Ore occurs in two main ore bodies designated as the "upper bench" and "lower bench", which could be mined separately. Examining engineers obtained samples from each ore body, and laboratory experiments were made on each sample. The Black Eagle group of claims is in Lander County, Nov., about 43 miles southwest of Battle Mountain. Ore occurs as a replacement of manganese oxides in shale and chert. The 2-ton sample of ore used for laboratory testing was taken by a Bureau of Mines examining engineer from an adit that partly transversed a 28-foot bed of ore. The property is controlled by Western Alloys, Inc.

Jan 1, 1951