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By S. H. Lorain

Shortly after the Strategic Minerals Act of 1939 we passed by Congress, the Bureau of Mines was authorized to begin a program of investigation of domestic sources of strategic minerals. Since World War I, the Philipsburg district had been virtually the only one in the United States that was producing manganese on a commercial scale. Consequently, the district was among the first to he investigated. During the summer of 1939, the Geological Survey mapped the geology and ore deposits of the district. In late July 1939 the writer examined the district for the Bureau of Mines. On the basis of this examination and of the work performed by the Geological Survey, the Bureau of Mines diamond-drilled at several properties in the district during the summer of 1940. This report reviews the mining history and geology of the district, and presents the factual data obtained by diamond drilling.

Jan 1, 1950

By R. Duncan Gardner

This paper describing the mining practice at the Harmony mine, Baker, daho, is one of a series being prepared by the Bureau of Mines on mining practices, methods, and costs in the various mining districts in the United States. About 150 tons of copper ore containing 4 per cent copper, 0.001 ounce gold, and 0.1 ounce silver, is being produced daily from the Harmony mine by the shrinkage method of mining. The ore is taken by an aerial tramway 1/3 mile long to the mill, where it is concentrated. The concentrate is shipped 8 miles by truck to the railroad and thence by rail to Utah for smelting.

Jan 1, 1930

By Loren R. Anderson

This is an Appendix of Volume I. It contains the results of the electric cone penetrometer soundings from the first phase of the testing program.

Jan 1, 1982

By R. J. Henry

This paper describing the mining practices at the Teck-Hughes mines at Kirkland Lake, Ontario, is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in various mining districts. HISTORY Prospecting was begun in the neighborhood of Kirkland Lake in 1906, but staking did not take place until 1911. Gold-bearing veins were discovered by surface trenching in 1913 on the mining claims which now make up the Teck-Hughes Gold Mines (Ltd.). A small mill was erected in 1916 after the completion of some underground exploration. A transmission' line was built in 1917 to the camp to provide adequate power for a vigorous underground campaign. Also in 1917 the present management took control operations since 1916 have been continuous,' with a steady increase in production to date.

Jan 1, 1930

By D. A. Reynolds, J. D. Davis

During early development of the blast furnace, Connellsville coke made entirely from Pittsburgh-bed coal proved to be an excellent fuel. The need for blending coking coals arose as the industry grew and it became necessary to carbonize coals having voking properties inferior to those of Pittsburgh coal Most coals carbonized today in continental Europe and this country are blonded: This practise has improved the quality of coke and permitted the utilization of coals that would yield inferior coke, if carbonized sepa- rately, The depletion of the world's better coking coals, which has been noted by leading coal technologists,2/4/wes accelerated during the recent war and. It is important, therefore, that reserves be evaluated and conserved. In the principal, steel-producing sections of this country, Pocahontas coals have been blended so extensively that the terms "low-volatile coking coal": and. "Pocahontas" have become virtually synonymous. Other low-volatile coals. have been used to manufacture metallurgical coke and will be used more extensively as, the supply of the better known and more accessible Pocahontas coals decreases. Recognizing the need for augmenting the supply of high-rank coking coals, the Bureau of Mines has included both low- and medium-volatile coals in its Survey of the Carbonizing Properties of American Coals, which was started with the cooperation of the American Gas Association in 1929. Twenty coals, 12 of low-volatile and 8 of medium-volatile rank, have been blended with high-volatile A Pittsburgh-bed coal, and five standard low- volatile coals have been blended with various high-volatile coals. Most of the results of carbonization tests of these coals and their blends have been

May 1, 1946

By A. W. Deurbrouck

This report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Webster County, W. Va. In 1964, approximately 825,000 tons of coal was produced in the county, of which 732,000 tons was mechanically cleaned in three preparation plants. The Sewell coal bed accounted for 94 percent of the coal produced. Twelve samples were collected from five coalbeds. Four of the samples would require upgrading to meet metallurgical requirements; two others of just over 8.0 percent ash would require some upgrading. In general the coalbed samples collected in the county were of medium-sulfur and medium-to low-ash content as received or after removal of the sink 1.58-specific-gravity material.

Jan 1, 1966

By Phillip N. Yasnowsky

This Bureau of Mines report examines the percentage depletion allowance rate structure in relation to several criteria that are indicative of U.S. mineral import dependence. These criteria are the minerals considered as strategic and critical for stockpiling purposes, the ratio of reserves to forecast cumulative demand (1976-2000) for selected minerals, and the U.S. net import reliance as a percentage of apparent consumption (1978), also for selected minerals in general, it was Found that there does exist a direct, although not perfect, relationship between the percentage depletion allowance rates and the degree of import dependence as indicated by these three criteria. The higher percentage rates tend to he associated with those minerals for which the United States is, or will likely he, heavily dependent on foreign sources. In addition, a basic discussion of the mineral depletion allowance is provided, including numerical examples illustrating the computation of the allowance under several assumptions. Also, the percentage depletion allowance rates for individual minerals are tabulated.

Jan 1, 1980

By W. H. Tomlinson

During the 9 years ended December 31, 1938, 188 fatalities resulted from preventable accidents in and around the coal mines of Indiana; 173 of these occurred at underground mines and 15 at stripping or open-cut operations. In addition, there may have been other unrecorded fatalities during this period. The two organizations receiving notice of accidental deaths at coal mines in this State are the Division of Mines and Mining and the Indiana Industrial Commission. Only deaths occurring at underground mines employing 10 or more men are reported to the former, as neither strip mines nor underground mines employing fewer than 10 men cone within the purview of the Indiana mining law. The mine inspectors have no Jurisdiction over this latter group of mines and do not inspect them. Fatalities at small "wagon" mines and open-cut operations are supposed to be reported to the Industrial Commission; however, in many instances deaths at small mines are not reported, the only record being a death certificate filed with the county or corporation health officer. Thus, many deaths in small mines escape attention, especially when the victim succumbs some time after the injury was received. The data presented here on fatalities in Indiana, during the past 5 years include several instances in which the only record available is a death certificate; possibly others have been overlooked. From 1934 to 1937 the fatality record was progressively worse, that of the larger underground mines in 1937 being more than twice the average for these mines for the previous 4 years and only slightly less than twice the average for all mines, including open-cut operations. The increase in deaths during 1937 was due to two explosions, with 20 fatalities in one and 2 in the other. The number of deaths in the larger underground mines was considerably less in 1938 than in the previous 4 years, but there was no improvement in the number of fatalities at the small mines, or at open-cut mines.

Jan 1, 1940

By Leonard F. Heising

Domestic production of Metallurgical-grade manganese has contributed such a small percentage of the United States industrial demands that areas known to contain large tonnages of low-grade manganese ore have been investigated by the Bureau of Mines to reduce this country's dependence on foreign ores. A major source of low-grade manganese is the Cuyuna iron range in Minnesota. The entire Cuyuna iron range is covered by an overburden of glacial drift that, in some places, reaches depths of 200 feet or more. Prospecting and exploration must be guided by geophysical methods, drilling results, or projections of exposures found in operating mines because there are no outcrops near the productive parts of the range. Past drilling for the purpose of outlining iron ore generally was confined to the highly oxidized zones. Much of the manganese with which the Bureau of Mines is concerned occurs in thin-bedded unoxidized iron formations, too low in iron content to have been of interest to those seeking commercial iron ore. The primary objective of the core-drilling reported here was to obtain cores of different classes of manganiferous rocks and to determine whether or not the samples were amenable to beneficiation.

Jan 1, 1959

By Albert W. Deurbrouck

This report describes the preparation characteristics of the significant coalbeds in Russell County , Va . Almost 2 million tons of coal was mined in 1961 ; 75 percent of the coal was cleaned mechanically in preparation plants in the county . The coal of Russell County is ranked as medium- to high- volatile bituminous , contains small amounts of sulfur , and generally requires some cleaning to reduce the ash content to limits acceptable for metallurgical purposes .

Jan 1, 1963

By John E. Kelley

Laboratory equipment, which simulates abrasive impacts between steel and minerals that might be present during pneumatic transport of coal, was used by the Bureau of Mines to characterize the potential explosion hazard of such collisions in an atmosphere of fine coal dust, air, and methane. A variety of coal mine rock materials, including sandstone, limestone, and pyrite-bearing limestone, were impacted with specimens of pipeline steel. Tests were con-ducted in atmospheres containing zero to 6.4 vol-pct methane mixed with zero to 300 mg/l coal dust. Coal dust in air alone was not ignited by abrasive impacts, but additions of as little as 1 vol-pct methane to the coal dust and air mixture resulted in ignitions. Steel impacting against sandstone caused ignitions in mixtures of coal dust, air, and methane, and the probability for ignitions increased with an increase in methane. No ignitions occurred with impacts of steel on lime-stone or pyrite-bearing limestone, even when large showers of sparks were produced. Studies of the effect of tangential collision velocity showed that no ignitions of coal dust, air, and methane occurred below 900 fpm (4.57 m/sec). Ignitions in coal-air-methane mixtures were found to be caused by a hot friction-induced smear on the impacted rock at the impact site rather than by sparks. High-speed photography was used to verify this observation.

Jan 1, 1976

By R. S. Warfield

Following World War II, the rapid increase in both military and civilian activity in the area served by the Alaska Railroad stimulated interest in the availability of local sources of nonmetallic minerals that might be used for building materials. Except for abundant sand and gravel and some pumice, the construction industry of the area depended entirely on high-cost imports for building materials of mineral origin. Because continued rapid growth was anticipated, development and use of local sources of such materials was advocated by both military and civil authorities to reduce the high costs of con¬struction and bolster the unstable economy of the area. The U.S. Department of the Interior began a program On included examining the numerous deposits of nonmetallic minerals accessible to the Alaska Railroad to determine their possible use as raw materials for the construction industry. Preliminary field investigations were made by the Geological Survey. The more promising deposits were subsequently examined and sampled by Bureau of Mines engineers, and the samples were subjected to the laboratory tests necessary to indicate the chemical and physical characteristics of the raw materials or their products. Such field and laboratory investigations were conducted on clay, shale, argillite, limestone, gypsum, and pumice taken from various parts of the area. In initial phasees of the work, done irate 1948 through 1952, many of the deposits examined were suitable for proctoring building materials. Results of the work completed during that period have been published in a Bureau of Mines report3 giving general information and detailed data on more than 35 deposits that were investigated.

Jan 1, 1962

By William A. Beck

Since bauxite mining began in the Irwinton District, Wilkinson County, Ga., in 1912, it has been on a small scale, as most of the deposits of high-grade ore are small. The bauxite has a high silica content, and its use has been largely limited to the chemical industry. Drilling under this project did not disclose any bauxite deposits of commercial value: However, numerous holes penetrated high-alumina clay deposits, but no attempt was made to delimit them, as the project was solely an exploration for bauxite. Bauxite was first discovered near Irwinton in 1907. The district covers virtually all of Wilkinson County and extends into the adjoining counties of Washington, Baldwin, and Twiggs. Mining was begun in 1912 by the Republic Mining & Manufacturing Co. on the Honeycutt, Parker, and Daniel properties, which are 1.5 miles from Wriley on the old Irwinton to Milledgeville Road.

Jan 1, 1949

By A. Oyler

The U.S. Bureau of Mines has compiled data on the major causes of fatal and nonfatal electrical accidents related to mining, and their associated costs, for the 1980-85 period. Specific electrical problem areas were identified, allowing future research to be focused on reducing the frequency of these occurrences. Recommendations for reducing the number of electrical accidents and injuries are provided. The four mining sectors for which data were gathered and compiled are (1) underground coal mines, (2) surface at underground coal mines, (3) underground metal-nonmetal mines, and (4) surface at underground metal-nonmetal mines. Nine categories of information pertaining to specific aspects of the accident are used in this report: activity engaged in when the accident occurred, source of injury, job title, mining method, location, machine, nature of injury, accident type, and part of body affected. The number of years of experience at the specific job the employee was performing when the accident occurred, time of accident, and in the case of nonfatal accidents, the total days lost per year, are also summarized.

Jan 1, 1990

By Jr. Karr

The Bureau of Mines studied the influence of carbonization method, temperature, and carrier gas on the composition of eight different low-temperature tars produced from a Colorado subbituminous coal. A fluidized bed was compared with an entrained bed, temperature was varied from 500° C to 650° C, and external heating using recycle gas as the carrier gas was compared with internal heating using oxygen-containing gas. The entrained bed yielded significantly more m-cresol and m-ethylphenol, indicating that thermodynamic equilibrium was more nearly approached in the system. Increasing the temperature greatly increased the yield of benzenes and naphthalenes, while paraffins, olefins, and total tar acids were reduced. Using oxygen in the carrier gas decreased the yield of low-boiling phenols and increased that of paraffins and olefins at 650° C.

Jan 1, 1966

By Wilbur I. Duvall

Twelve millisecond delayed blasts in four limestone quarries in Iowa were instrumented with arrays of vertical velocity gages to determine if the direction of propagation through the rock or the method of initiation of the blast had any effect upon the level of vibration. Two gage arrays approximately 90° apart were used to test the effect of direction of propagation. The vibrations from blasts initiated by three methods were recorded. Vibration records from these tests were analyzed for peak particle velocity as a function of distance from the blast. The data are shown to fit a power Law equation. Direction of propagation is shown to affect the value of the exponent n. The effect of charge size per delay interval on the level of vibration is removed from the data by scaling the travel distance by the square root of the charge weight per delay period. The method of initiating the blasts is shown to have a strong effect upon the level of vibration and the spread in the data from one shot to another.

Jan 1, 1963

By David A. Benjamin

From 1986 to 1989, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the 59,600-acre Mexican Mountain Wilderness Study Area (UT-060-054) in order to evaluate its identified mineral resources. The study area is located in Emery County, UT, about 24 miles east of Castle Dale, UT. A review of the geologic and mining literature, and a field examination identified two uranium prospects in the Wilderness Study Area, and three copper prospects nearby. One-hundred ninety-five rock samples were taken.

Jan 1, 1989

This chapter analyses the parameters influencing initial design of communication systems, for new mines and upgrading existing systems. Paragraph 5.2 outlines those variables that must be taken into account during the design stages of a new wired phone system. Recommended features, general requirements, and how they can be implemented are treated in this section. Paragraph 5.3 describes ways of improving or extending the range of trolley carrier phone systems and pager phone systems already installed in the mine. 5.2 New Phone System Design The task of designing an adequate communication, control, and monitoring system for an underground mine must be addressed on a system basis. In addition to insuring that effective voice communication is established, any new system should take into account present and future requirements of remote control and monitoring functions. Chapter 4 illustrated the drastic savings in response time that can be realized when remote control and monitoring are integrated into the overall communication system. The importance of including control and monitoring in the overall design plan for any system cannot be overemphasized. Because each mine is unique, and thus usually has its own special operating characteristics and communication requirements, there is no such thing as "the one best system" to meet the requirements of all mines. The optimum communication, control, and monitoring system for a mine must be one that has been tailored to meet the special requirements of that particular mine. Factors that must be considered during system design include- a. Type of mine and mining methods (low- or high-seam coal, deep hardrock mine, stope caving, longwall, room and pillar, etc.). b. Maximum number of working sections. c. Expected mine growth rate and eventual maximum size. d. Haulage methods (tracked trolley, diesel, belt, etc.). e. Underground power distribution system (dc, ac, or both). f. Features desired (two-way radio paging, private line capability for emergency use, etc.). g. Redundant or backup systems for use during outages of the normal system. Although no two mines are alike, the following items have been established as the main characteristics desired for any underground communication system: 1. Multiple Communication Paths to Outside--the objective here is to give all telephones a second method of communicating with the surface. 2. Audible Emergency Signaling--the communication system provides the main means of alerting miners during emergencies. The system should include means to broadcast distinct audible signals for emergency signaling. Initiation of these signals should probably be controlled from. a central outside point, such as a surface control room. 3. Emergency Override--provisions should be included to permit any conversation to be overridden with emergency communication. 4. Selective Area Page--as mines grow larger it is apparent that the entire telephone system paging mode need not be activated each time a call is initiated. When the general area of a

Jan 1, 1984

By B. A. Rogers

The problem of obtaining enough manganese for use in the manufacture of steel appears likely to recur when international relationships are disturbed and to become serious at any time when the United States is cut off from its customary supply. Some idea of the problems that an e under war conditions may be obtained from a description given by Ellicott3/ in 1918 before the American Iron and Steel Institute. This condition arises because in normal times there is an economic advantage in importing available high-grade foreign ores to the neglect of our own less satisfactory resources. That considerable low-grade manganese ore and a much smaller amount of high-grade material are available in this country is well known from geological surveys 4/ and has been confirmed by Bureau of Mines investigations. Locations of the various deposits are indicated in figure 1. The possibility of greatly expanding domestic production was actually demonstrated from 1913 to 1918, when the annual production of manganese from domestic ores rose from about 4 percent to approximately 35 percent 6/7/ of the total consumption of ferromanganese and spiegeleisen. In idea of how domestic production compares with total consumption in the United States can be obtained 1 from figure 2, taken from the Minerals Yearbook8/ for 1970. Assuming that it is possible to increase production of manganese ores sufficiently to supply all our needs, such a program presumably would require 2 or 3 years, and the cost of production would certainly rice considerably, for some time at least. For

Jan 1, 1941

By Kenneth J. Miller

The Federal Bureau of Mines coal-pyrite flotation process has been modi¬fied to produce a concentrated final clean coal slurry underflow that could be dewatered more effectively by filtration or centrifugation. This change was accomplished by redesigning the Bureau's two-stage flotation pilot plant facility and running the second-stage flotation step with undiluted or only partially diluted first stage coal froth concentrate. Results of the pilot plant flotation tests showed that substantial sulfur reduction could be achieved by flotation with undiluted pulp but some dilution is recommended for maximum selectivity. For example, coal-pyrite flotation in slurry of 25 percent solids yielded clean coal products analyzing as low as 0.7 percent pyritic sulfur and froth reject products containing slightly over 3.0 percent pyritic sulfur. In comparison, coal-pyrite flotation with pulp diluted to about 12.5 percent solids yielded clean coal containing as low as 0.4 percent pyritic sulfur and froth reject of 5.6 to 6.7 percent pyritic sulfur. Despite the need for some dilution, it was concluded that excellent coal-¬pyrite flotation selectivity could be achieved without diluting to 6 or 7 per¬cent solids as done in the earlier work. Thus the economics of coal-pyrite flotation would be improved by easing clean coal dewatering problems and by reducing second-stage flotation cell volume requirements.

Jan 1, 1977