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By W. H. Lewis

This Bureau of Mines report and its companion report (Information Circular 9073) have been prepared as a complete reference on underground coal mine lighting. This report discusses system design criteria and procedures, data and specifications to aid in selection of suitable mine lighting hardware, and guidelines for system installation and maintenance. Topics include light measuring techniques and instruments, illumination regulations for underground coal mine environments and equipment, lamps and ballasts, available mine lighting hardware, design and evaluation of coal mine illumination systems, and installation and maintenance of a mine lighting system.

Jan 1, 1986

By T. J. Ballard, Austin B. Clayton

"The Union Copper mine is in the Gold Hill district, Rowan and Cabarrus Counties, N. C.The mine was discovered in 1799 and first worked as a gold mine; but copper was encountered at depth, and the property became an important producer of copper. It is estimated that the mine produced 5,000,000 pounds of copper before operations were discontinued in 1907.As part of the strategic minerals program, the Bureau of Mines conducted a development project on the property from July 1943 to November 1943. Eight diamond-drill holes, totaling 2,500 linear feet, were drilled to delineate the ore body. Analyses of 205 core samples were made.Tabulations of sample analyses and drill-hole logs are presented in this report.The project work embodied in this report was under the immediate supervision of Austin B. Clayton, project engineer, and the general supervision of H. B. Ewoldt, district engineer for North Carolina and Tennessee. The preliminary report, written by Austin B. Clayton, was revised and the various figures redrawn for publication by T. J. Ballard under the general supervision of M. H. Kline, chief, Raleigh Branch, Mining Division.Acknowledgment is due the Metallurgical Branch for analytical determinations of the samples.The mine property is 1.5 miles southwest of the village of Gold. Hill, N. C. (fig. 1). Gold Hill is on U. S. Highway 52 between Salisbury and Albemarle and on a branch line of the Southern Railway. The latitude is 350 30' and longitude 80° 21 The tract consists of 553-1/2 acres in Cabarrus and Rowan Counties.A tentative list of the surface-rights ownership is as follows: William Hoy Barringer - 16 acres, A. W. Tucker - 1 acre, Frank Wagoner - 4 acres, and George Barringer - 3-1/2 acres, in Cabarrus County; A. W. Tucker - 2 acres, H. N. Hedrick - 54 acres, and William Atkins - 473 acres, in, Rowan County, N. C.The mineral rights are owned by Alfred Rossiter, Alice R. Hesslein? and the estate of the late Bella Rosenblatt. The attorneys for the owners are Neidle & Taylor, 6 East 45th Street, New York City.The Union Copper mine is in the Cold Hill mining district of North Carolina where gold was first discovered in 1799. The upper parts of the veins in the district were first worked for gold; however, the increase in the sulfide content of the veins with depth rendered the amalgamation process for gold recovery ineffective, and the mines were closed.The period of greatest activity at the Union Copper mine was from 1899 to 1906. At an earlier period the oxidized and leached part of the lode near the surface was mined from a working known as the ""big cut,"" the reported yield of which was $300,000 in gold.3/ The mine has not been operated since 1907.J. T. Pardee3/ lists the probable value of the production of the Union Copper mine as $1,050,000, of which about $675,000 was the value of some 5,000,000 pounds of copper produced."

Oct 1, 1948

By S. Ralph Austin

This Bureau of Mines investigation determined the effects of so-called annealing at high temperatures on radon-222 emanation from domestic uranium ores. Concurrently, a method was developed for closely estimating the emanation coefficients of hot samples from measurements of their gamma activity after cooling. Emanation coefficients of 102 samples from 14 domestic areas of past, present, and possible future uranium production were investigated using modifications of the closed-can, gamma-only assay method at and after cooling from 100° to 1,000° C. True annealing probably does not occur below 500° C. In limited investigations at 500° C and above, effects of annealing are masked by the effects of other parameters. Emanation is commonly less at one or more of the steps investigated in the 100° to 500° C range than before heating. This decrease is tentatively attributed to water loss at temperatures dependent upon the minerals present. The average sample emanates least at 300° C; emanation increases with higher temperatures to at least 900° C. Emanation decreases sharply on cooling, but it is partially restored by prolonged exposure to the atmosphere at room temperature. Higher than average emanation of coffinite ores at 500° C and above may be related to destruction of the coffinite crystal structure.

Jan 1, 1979

By Raymond B. Ladoo

Silica , or silicon dioxide , ( Si0, ) , occurs in a free state chiefly as quartz , but hydrous silica ( amorphous silica carrying a variable amount of combined water , 2 to 13 per cent ) , occurs as opal , flint , diatomaceous earth , tripoli and so on . Quartz is found in many forms , the most important of which are ; As vein quartz; quartzite ; sandstone ; silica sand and gravel ; as crystals or crystalline grains , masses or aggregates in igneous rocks such as granites , dicrites and pegmatites . Commercially silica is used in many ways , but ordinary uses of sand and gravel are so well known that they will not be considered here .

Jan 1, 1922

By I. O. Salyer

This research was conducted with the objective of suppressing the respirable dust in coal mines by foam application. A formulation was developed for making a water-based, high-expansion, and limited stability foam. A horizontal boring machine was used as a laboratory coal mining model for generating coal dust. A modified laboratory foam generator was built. Foam was applied directly to the point at which dust was being formed by the cutter of the boring machine working against a block of coal. Coal dust was sampled with an impinger and analyzed for the particle count and particle size distribution. Coal dust suppression test results on freshly generated dust have demonstrated very clearly that in laboratory scale experiments over 90% of the respirable coal dust can be suppressed by foam. These tests were run when initial coal du t concentrations were 10 and 70 million particles per cubic foot (mppcf).

Jan 1, 1970

By C. A. Herbert

Timber decay is due largely if not wholly to a fungus growth on the timber from which it derives' food; a warm, moist atmosphere is necessary for rapid growth. The decay is spread from infected timber to sound timber by countless microscopic spores or seeds given off by the fungus growth and carried by air currents or by long, cottonlike threads, which spread from timber to timber. Haulage roads in most mines in the central coal fields are also return aircourses; hence moisture and temperature conditions are ideal for the rapid decay of mine ties and mine timber. Possibly the return air, which contains a higher percentage of carbon dioxide than normal outside air, also stimulates the growth of fungi. Those familiar with coal mining have observed the more pronounced growth of fungi and decay of timber in poorly ventilated worked-out sections of mines where the air is moist and where usually the percentage of carbon dioxide in the air is considerably above normal.

Jan 1, 1934

By James A. West

The South Asian countries of India, Pakistan, Afghanistan, Ceylon, Nepal, Bhutan, and Sikkim arc to varying-degrees just beginning to achieve significant economic and industrial development. These countries are richly endowed with certain mineral resources, and development of these resources is being accelerated. In 1965, the mineral industry remained a relatively small sector of the region's economy, accounting for only about 1 percent of its estimated gross national product of $62,528 million. Nevertheless, the estimated $630 million total value of minerals produced in South Asia during 1965 represented an increase of nearly 15 percent t over that of 1964. India continued as the dominant mineral producer of the region, accounting for 85 percent of the total value of all minerals produced ill 1965. India increased its output of iron ore, manganese, mica, coal, and petroleum. Pakistan accounted for 13 percent of the value of the region's output and recorded increased output of iron ore, chromite, coal, natural gas, and most other minerals. The small mineral industry of Ceylon attained remarkable growth in the production of ilmenite, graphite, and gem stones. The mineral industry of Afghanistan remained relatively insignificant, although development of large known resources of natural gas was continued, Nepal, Bhutan, and Sikkim produced no commercially significant quantities of minerals in 1965.

Jan 1, 1967

By E. L. Rawlins

A previous report4 has explained that pipe lines for the transmission of natural gas should be buried to minimize temperature fluctuations because when excessive the latter decrease accuracy in measuring gas volume and increase leakage of gas due to expansion and contraction in the pipe joints. These effects are governed by the rapidity of the temperature fluctuations and by the total variation over a period of time. The temperature of gas flowing through a pipe line depends to a large extent, upon the temperature of the ground adjacent to the pipe; hence, fluctuation of the ground temperatures at various depths determines the economic depth at which pipe lines should be buried. Scope and Purpose of Report This report covers a record of the daily atmospheric temperature fluctuations at Bartlesville, Okla., for 12 months and a-similar concurrent record of the temperature variation 1, 2, 3, and 4 feet below the surface of the ground.

Jan 1, 1928

By James L. Konchesky

Crushed coal, consisting of a wide range of sizes, was effectively blended by recycling it through a bin equipped with a particle distributor. Vertical blending was accomplished by simply recycling the coal; it was not significantly influenced by the horizontal blending that was achieved by the distributor. The method was effective, even though the coal was wet and possessed poor flowing characteristics. Recirculation appears capable of providing uniform blends of solids that can be more efficiently processed. Recirculation also appears useful, preceding packaging operations, to insure for blending of solids into specification products. Continuous measurement of the bulk density of the coal by a gamma ray meter proved to be an effective monitor of vertical blending effectiveness.

Jan 1, 1972

By J. M. Singer

The objective of this investigation was to determine minimum air velocities and entrainment rates for coal and rock dust dispersion in wind tunnel experiments under conditions that simulate dispersion from surfaces in coal mines where airflows are induced by weak gas explosions. Dust deposits were bed-or ridge-shaped; particle sizes were 6 to 80 microns (cohesive deposits) or 100 to 150 microns (free-flowing deposits); and wind tunnels were 7.62 cm wide by 5.08 cm high by 300 cm long, and 2.4 m wide by 1.5 m high by 215 m long. The investigation showed that minimum air velocities (directed at mid-height) of separate, layered, or mixed piles of coal dust and rock dust were within the range 5 to 30 m/sec, independent of size of wind tunnel. This finding considerably facilitates scaling of data to mine-size passageways. Free-flowing deposits dispersed relatively slowly by single-particle detachment; cohesive dusts dispersed faster by the breaking and lifting of large clumps along weak failure flames; particle dispersion occurred in flight. Layered or mixed deposits of coal and rock dust did not disperse selectively. Semiempirical expressions were derived relating minimum air velocities and dispersion rates to dust-pile geometry, cohesion, porosity, and bulk density.

Jan 1, 1972

By B. H. Eccleston

Experimental data were obtained from two medium-duty diesel engines derated to qualify for use in underground mines. Gaseous and particulate emissions from these engines were measured and results provide information on the effect of exhaust treatment devices on the emissions. The devices in the study were a catalyst, a particulate trap, and an exhaust gas cooler of the water scrubber type. Emission levels of carbon monoxide and hydrocarbons were observed to be very low in comparison with emission levels of comparable engines in full-rated operation. Oxides of nitrogen and benzo(a)pyrene content of the exhaust also were found to be somewhat low in comparison with previous findings. For particulate reduction, the combination of a particulate trap and a scrubber was observed to be the most effective combination tried; in some cases, over 60 pct particulate reduction was effected by the trap-scrubber combination.

Jan 1, 1981

By R. V. Ramani, A. S. C. Owili-eger

A mass balance equation can be written for the unit block of Figure 7 for changes within the volume during time At as: [ ] where x and y are the coordinates; q is the flow across any surface; p is the density of the fluid flowing through the medium; qvol is the volumetric flowrate; @ is the medium porosity; and Ax and Ay are the dimensions of the block. The subscripts t and (t+At) denote time levels and At is the change in time. Writing this equation in nota- tional form and on rearranging, the following expression is obtained:

Jan 1, 1974

By A. W. Khair, S. J. Jung

"A fundamental study of fragment size distribution and characteristics of fracture pattern is presented for the dynamic penetration of a conical bit into coal block. In this paper, damaged zones during crater formation and fragment size distribution were studied. Bit with a sharper tip angle and a smooth body configuration performed better penetration. Results suggest that in coal cutting the trend should be toward the face cleat direction using a sharper angled tip bits which consumes less energy for an optimum range of penetration depths, thus attaining maximum cutting efficiency and reducing fine fragments.1. INTRODUCTIONMuch research in the past has been done on energy requirements and mechanism of energy dissipation for ideal rock fragmentation in cutting process. However the mechanisms of energy dissipation or failure criteria for rocks in cutting process in order to evaluate the efficiency of energy requirements in specific rock fragmentation is not well understood. The formation of a crater in rock under the impact blow of a bit has been observed experimentally (Hartman, 1959). It is known that directly beneath the edge of the bit the rock is crushed into fine powder, toward the sides of the crater it chips out into relatively large fragments. (Sikarskie & Cheatham, 1973). Singh et al. (1967) investigated the cratering process under the two different conditions of static and dynamic loading. They found that the amount of energy consumed per unit volume of crater is unequal for the two different loading conditions. A complex network of fractures often extends downward and laterally into the rock below the bit. The surface of the specimens showed that the dynamic loading damaged larger area then the static loading."

Jan 1, 1989

By Russell R. Trengove

The Bureau of Mines developed by core drilling the Cove Meadow copper property, also known as the Patterson property, from May 6, 1949, to August 6, 1949. It is in the Cove Meadow mining district, northwestern Humboldt County, Nev., 102 miles northwest of Winnemucca. The purpose of the work was to determine possible reserves in a mineralized shear zone in andesite that has been partly explored by several surface cuts and two shallow underground workings. Production from this zone to August 1, 1,949, was 98 tons of hand-sorted copper ore assaying 5.1 percent. The development work performed by the Bureau of Mines comprised a study of the geology, mapping the area, sampling the outcrops, and exploring by diamond drilling the shear zone adjacent to the fault. Seven holes were drilled for a total of 1,246 feet. Mineral reserves indicated by the project are confined to a length of 500 feet along the strike.

Jan 1, 1950

By E. E. Maillot

In 1943, diamond drilling by the Bureau of Mines, comprising 11 holes which totaled 1,295.6 feet, showed that the pegmatite at Black Mountain consisted of shallow lenses in interbedded biotite-quartz-schist and impure quartzite. The average thickness of the pegmatite was 9.7 feet. Mineralization had a zonal arrangement. Beryl was most abundant near the footwall contact of the pegmatite. The average estimated beryl content of the pegmatite exposed at the surface was 0.81 percent, and the highest content of any pegmatite area was 1.75 percent. Other economic minerals were scrap mica, feldspar, spodumene, and lepidolite. Representative samples of the Black Mountain deposit failed to yield high-grade boryl concentrates by straight flotation owing to the presence of considerable spodumene. By employing heavy medium separation to remove the spodumene, 75.4 percent of the. BeO wan recovered in a flotation concentrate assaying 10.4 percent BeO.

Jan 1, 1949

By R. S. Dean

The principle of explosive crushing depends upon the fact that an expandable substance contained within the pores of a solid body will disrupt such a body upon expansion. Such expansion may be obtained by the detonation of an explosive or by the sudden release of pressure of a superheated liquid. That this principle of disruption may be applied to minerals rests on the fact that cracks, cleavage planes, and pores exist in all mineral to an extent hardly conceived possible heretofore. Crushing by this method takes advantage of force applied from within the mineral rather than from forces applied from without. The application of a force from within would appear to be more effective. A consideration of the possibilities of such a method for crushing led to some experimental work of a preliminary nature, the results of which are embodied in this paper. No systematic program was followed in the work and the results are, therefore, not final and far from complete. The success attained so far, with the mediocre apparatus available seems to warrant a preliminary report, with the expressed hope that the work may be carried on as well-outline program covering such phases as have been impossible to investigate at this time.

Jan 1, 1931

By John A. Breslin

This publication provides an historical overview of research undertaken by the U.S. federal government over the last 100 years to improve the health and safety of our nation?s miners. Federal research efforts began with the establishment of the U.S. Bureau of Mines (USBM, or the Bureau) in 1910. They have continued over the past century, even after the Bureau?s closure in 1996. It is hoped that this publication will give the reader an appreciation for the work of mining health and safety researchers over the past century, and of the miners served by this research. Although not a comprehensive history, this report highlights the key organizational changes made within the Bureau and the federal government that affected mining safety and health research. Some mention is also made of Bureau research not directly related to mining health and safety. Note that the work classified as safety and health research has varied over the last century. For example, before 1970 the Bureau separated mining research and safety and health research. At that time, mining research included ground control and methane drainage because they had direct implications for mine safety. Explosives research was also reported separately from health and safety, even though permissible explosives research was obviously related to safety. Therefore, where budget figures from the Bureau are mentioned in this report, it is often not possible to separate safety and health research from other types of research. This history is generally chronological, with a few exceptions. Because of their prominence and direct links to Bureau research, most of the Public Health Service mining studies completed before 1970, when NIOSH was established, will be discussed in a single section, even though the work spanned many decades. Likewise, for convenience, the brief histories of the Bureau?s mining research centers are located in one section.

Feb 1, 2010

By Michael S. Miller

In 1987, 1988 and 1989, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied the Sperry Creek Wilderness Study Area (OR-003-035; 5,600 acres) and the Gold Creek Wilderness Study Area (OR-003-033; 13,600 acres), plus an additional area (OR-003-033; 2,180 acres) adjacent to the Gold Creek Wilderness Study Area. The wilderness study areas and the addition are south of the Malheur River and are about 20 miles east of Juntura, Oregon. The wilderness study areas and the addition are underlain by volcanic rocks, predominantly basalt and rhyolite flows, breccias, and welded ash-flow tuffs. Lacustrine deposits containing diatomites occur mainly at the east side of the Gold Creek Wilderness Study Area and addition. Alluvium lies along the Malheur River, in terraces and fans south of the Malheur River, and along the floors of some creeks. Shear zones and faults have offset the rocks and provided channels for eruption of volcanic rocks and epithermal mineralization by hot springs.

Jan 1, 1989

By T. L. Joseph

The purpose of this article is to describe briefly the operation of a 6-ton blast furnace on a charge of bauxite, limestone, iron ore, and cast-iron turnings and to point out the bearing which smelting such a charge has upon the production of alumina cement. One object of the experiment, conducted by the Bureau of Mines in cooperation with the Aluminum Co. of America, was to determine whether tae so-called Pedersen process3 can be applied to the blast furnace. This process consists of smelting a charge of bauxite, iron ore, and. limestone, and results in to products. One is a slag containing about 50 per cent of A1203 and is intended for use in manufacturing aluminum, and the other is iron low in sulphur. Complete details of the test are published in other reports4. Blast-furnace slag is now recognized as a satisfactory and economical raw material for making Portland cement, Wm. A. Forbes5 has recently reported that in 1926 an important steel interest used well over 1 million tons of slag in producing about 24 million long, tons of cement. This is equivalent to about ½ ton of slag for each ton of cement. Alumina cement can be made direct in the blast furnace. Its physical character would have to be changed by grinding, but no change in its chemical composition would be necessary.

Jan 1, 1928

By N. A. Eilertsen

This report describes field investigations conducted in 1953 of two occurrences of manganese and a separate magnetic anomaly in the Southern manganese district of Aroostook County, vicinity of Houlton, Maine -the Pierce deposits, in Hammond Plantation Township; the Burnham anomaly, also in Hammond Plantation; and the Nickerson-Farm prospect in Hodgdon Township. The manganese occurs in a thinly laminated sedimentary rock containing manganiferous carbonate interlayered with fine-grained metamorphosed sediment, rich in chlorite or hematite. The surrounding rocks are mostly dark gray-green slates. Samples composited for metallurgical testing from the Pierce deposits and the Nickerson-Farm prospect assayed 9.0 to 12.3 percent of manganese. More than 90 percent of the manganese could be extracted with sulfuric acid, but in most instances 30 to 40 percent of the iron was also extracted. Leaching tests indicated that, after being reduced in a hydrogen stmosphere at 600° C., about 85 percent of the manganese could be selectively extracted by a solution of ammonia-ammonium carbonate with iron extraction of only 14 percent.

Jan 1, 1958