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By Fred W. Snow

This paper describing the mining practices at the Magma mine, Superior, Ariz., is one of a series being prepared by the Bureau of Mines on mining prac¬tices, methods, and costs in the various mining districts in the United States. At present (1929) practically all the mineral production in the Superior district is from the Magma mine of the Magma Cooper Co. The ore is mined for its copper but contains associated silver and gold. Both direct smelting ore and ore of concentrating grade are produced. The mining methods now in use at the Magma mine were adopted or developed as knowledge was gained of the physical condition of the ore bodies and the inclosing formations; the wall rock is soft and crushed and the ore is relatively hard. In general, existing methods have been adapted to fit local conditions, but some of the mining practices used were originated at this mine. Most of the ore is mined by a combination of rill stopes and pillar stopes. The pillars are extracted by underhand mining.

Jan 1, 1929

By Paul M. Tyler

One by one new metals come to share the burden of modern industry. Long before the Christian era potters and glass workers employed fine and costly blue pigments that contained cobalt. Cobalt blue class has been found in the tombs of the Egyptians and in the ruins of Troy, and many of the colors used by the ancient Greeks and Romans contained cobalt. The ancients, however, were apparently unaware that the colors they used were caused by cobalt, and it was not until late in the 17th century that the existence of the element was recognized, Writers in the Middle Ages referred to "cobalos" as an evil spirit that haunted mines and caused trouble to the miners. Subsequently the German worms "Kobold," meaning goblin, came to be applied to any baffling mineral and particularly to minerals that resembled ores but failed to yield metal when smelted. Even to-day there is something of an air of mystery about cobalt, and a medieval cloak of secrecy still surrounds many of the metallurgical processes employed in its production. "Zaffre" was mentioned about the middle of the sixteenth century by Biringuccio, and in 1735 the metal war, first prepared by G. Brandt. To preparation of cobalt compounds, however, must have been carried on in at least a small way ever since the opening of the silver-cobalt deposits of Schneeberg in 1470. By 1790 there were 25 works engaged in the industry, rust of them located in Saxony, but the total output of these works probably did not exceed 300 tone of cobalt annually, mostly in the fore of smalt. The smalt which contained approximately 6 per cent cobalt was sold in Venice in 1520 at about 16 cents a pound. A few refineries in Holland supplied the Irish linen trade, contributed a farce amount to the Dutch linen industries, and alto provided smaller quantities for the manufactuer of litmus in Holland. A complete description of the early [histor,] of the cobalt industry in Saxony, is given by Mickle in the Deport of the Bureau of Mines of Ontario, vol. 19, 1913, pt. 2, pp. 234-251.

Jan 1, 1930

By L. A. Conley

This report, covering the period January through December 1976, contains abstracts of articles related to cost engineering and economics for chemical and petroleum plants, mining, and other mineral industries from the following periodicals: 1. Air Pollution Control Association Journal 2. Chemical Engineering 3. Chemical Engineering Journal 4. Chemtech 5. Coal Age 6. Coal Mining and Processing 7. Combustion 8. Drilling-DCW 9. Electrical World 10. Engineering and Mining Journal

Jan 1, 1977

On July 1, the Bonneville Power Administration announced a 25% power cutback because of lower than normal stream flow. In September, the Aluminum Company of America (Alcoa) announced plans to shut down one 23,000-ton-per-year potline at its Vancouver, Wash., primary aluminum smelter. Alcoa also announced that the last of four potlines at its Point Comfort, Tex., primary aluminum smelter would be restarted in October. A new 3-year contract was signed and workers at three Alcan Aluminum Ltd. primary aluminum smelters in Canada returned to work. It was estimated that it would take about 3 months before the smelters were operating at full capacity.

Jan 1, 1979

6784. Barnes, V. L., and Romberg, Frederick. Gravity and Magnetic Observations on Iron Mountain Magnetite Deposit, Llano County, Tex. Geophysics, Menasha, Wis., vol. 8, No. 1, 1943, pp. 32-45. An outcrop of magnetite in the Central Mineral region of Texas is explored experimentally with a dip needle and a gravity meter. Two anomalies are observed, one due to the outcropping body and one probably due to a previously unknown body close to the outcrop. The possible attitudes of the bodies are discussed, and their masses and probable dimensions are computed from the gravitational observations. - Author's abstract.

Jan 1, 1943

By Julius G. Chang

Against the receding background of the October stock market crash and the December overhang of inventories, the economy began with a shaky start in 1988. As 1988 began, the Administration's estimate of real growth for 1988 had just been reduced from 3.5% to 2.4% and economists and other ob-servers were concerned that the expansion that was 5 years old might be near the end and that a recession might be around the corner. The ensuing moderately strong economic activity, however, belied all the negative signals that were evident earlier, and the real GNP continued to grow at an estimated 2.3% annual rate during the first quarter of 1988, extending the ongoing recovery into the sixth year (table 1.). The relatively accommodative policy of the Federal Reserve Board (the discount rate was cut by 0.25% in January), a strong performance by the export sector, and the revival of consumer spending were major forces underlying the economic strength. But as the quarter drew to a close, signs of tight capacity utilizations were apparent in many of the export and capital goods sectors, including textile, chemical, plastic, metal, and machinery. Employment was at a record high level while the unemployment rate was close to a historical low. Prices were rising at a faster pace than those of 1987, and the dollar resumed its slide after a brief recovery in January and February. These factors gave rise to the fears of higher inflation. Long-term interest rates increased, casting a pall over the prospect of a robust growth for the rest of the year.

Jan 1, 1988

By Edmund Newton

The Haile mine has been the outstanding gold-mining operation and the largest single producer of gold in the Appalachian region. Gold was discovered at the Haile in 1827, previous to the present operation, production has been nearly $4,500,000 (gold at $20.67 per ounce.) from somewhat over a million tons of ore, with an average extraction of about 70 percent. The Haile property, now operated by Haile Gold Mines, Inc., is in the southern part of Lancaster County, South Carolina, 3-1/2 miles northeast of the town of Kershaw and 55 miles north of Columbia, the State capital. (See fig. 1.) The corporation has a lease and purchase contract on 1,805 acres, covering the present productive area. In addition, it holds lease contracts on 1,500 acres additional adjacent to this area.

Jan 1, 1940

By Carl L. Bieniewski

U.S. molybdenum production increased fivefold from 18.2 million pounds in 1946 to 90.5 million pounds in 1966, and constituted 87.3 percent of the total free world supply in the 1946-66 period. Mining development in other free world countries in the next few years may reduce the magnitude of the U.S. position, although similar development planned for the United States may counteract some of the relative gains by those countries. In 1966 two-thirds of the reported molybdenum consumption in the United States by end uses was as an alloying element in steel. Molybdenum also has important use as an alloying element in iron and high-temperature alloys. Consumption of molybdenum metal for making fabricated parts has increased in the past few years, especially in the space and nuclear industries. Molybdenum compounds are used mainly for making pigment, catalysts, and lubricants. Based on producer reports of shipments of primary products to domestic customers, U.S. consumption of molybdenum increased from 16.5 million pounds of molybdenum in 1946 to 65.6 million pounds in 1966. U.S. molybdenum reserves are now estimated to be 5.9 billion pounds of recoverable molybdenum, an increase of 2.1 billion pounds above previous estimates. Molybdenum ores account for 71.4 percent of the reserves, copper ores for 22.3 percent and copper-molybdenum, tungsten, and uranium ores for 6.3 percent. Several methods for predicting future demand are illustrated and estimates of demand using these methods were made for 1975. Based on present capacities and announced company plans for future developments, estimates of annual production were made for 1967 through 1975 for the United States, Canada. Chile, Peru, and the free world. These data indicate that molybdenum production in 1975 for the free world is expected to be 246 million pounds with the United States producing 68.2 percent and Canada, Chile, and Peru 30.3 percent.

Jan 1, 1970

By S. H. Ash

THE MAGNITUDE of the anthracite industry's drainage problem in the Lackawanna River drainage area is realized when it is known that in 1948 the 27 pumping plants in this region pumped over 48 billion gallons of water to the surface from the mines in the Lackawanna Basin of the Northern field. This is almost 92,000 gallons per minute pumped against an average hydrostatic head of over 300 feet for that year. By comparison, Lake Wallenpaupack, the largest artificial body of water lying wholly in Pennsylvania, contains 71 billion gallons of water in its 24-square-mile area: the volume of water pumped from the mines in the Lackawanna Basin during 1948 was approximately 68 percent of that impounded in Lake Wallenpaupack. The Lackawanna. River and its tributaries drain a troughlike area of 345 square miles. The synclinal axis of this trough lies within the coal measures. All surface drainage into the valley must traverse some part of the coal measures. On the basis of 45.03 inches of rainfall recorded by the Scranton station of the United States Weather Bureau for 1948, the runoff from the Lackawanna River drainage area during that period was 135 billion gallons, approximately three times the volume of water pumped by all mine pumping plants in the Lackawanna. Basin of the Northern field during 1948. In other, words because of the pervious condition of the strata overlying the mine workings, approximately one-third of the total runoff in the Lackawanna River drainage area becomes mine water. This report, reveals that less than 7 percent of the 72 miles of pervious stream beds examined between Archbald and Pittston have been unproved.

Jan 1, 1952

By T. J. Ballard

"INTRODUCTION The Buck. Creek corundum area of Clay County, North Carolina, includes one of the largest single masses of peridotite outcrops in the whole Appalachian Range and has been described by Pratt, an early authority on corundum, as offering one of the best potentialities for corundum production in North Carolina.Two principal types of corundum deposits are found at Buck Creek the vein type and the corundum-bearing amphibolite dikes.The vein deposits occur in structural fissures that strike north to northeast in a gangue of feldspar, zoisite, an, chlorite. The corundum is generally coarse-grained and good-quality. The corundum content varies from several percent to 50 percent.The corundum in the amphibolites is more or less disseminated through the dike, is generally lower-grade, and is less in quantity, than the vein corundum. About 50 percent of the amphibolite corundum is coarse enough for snagging-wheel grade but is difficult to separate from the amphibolite.Production from the Buck Creek area has been small and came mainly from high-grade pocket in the vein deposits. Pratt 3/ reports 300 tons of corundum ore was produced to about 1896. No record of subsequent production is available.The critical shortage of corundum during the war, due to transportation difficulties and the depletion of deposits abroad, prompted the Bureau of Mines to investigate domestic reserves.After a favorable report was obtained on the Buck Creek area, the Bureau began exploration of the deposit in September 1943 and continued until February 1945."

Apr 1, 1947

By J. Ritchey

This report describes the engineering feasibility and economic advantages of using a mobile bridge-type cross-pit belt conveyor system in conjunction with a large dragline to excavate and transport spoils in a typical Western surface coal mine. The studies show that such a system could be built to survive operational and climatic mining conditions, and that its implementation would offer a reduction in both acquisition and operating costs versus conventional mining units of comparable capacity. Reclamation costs can also be significantly reduced, and the total reclamation process accelerated, making the cross-pit conveyor system attractive to mine owners and environmentalists alike.

Jan 1, 1976

By L. C. IlsLey

"The use of trailing cables on cutting machines, loading machines, and similar electrically operated apparatus is recognized as a necessary adjunct to the economical operation of such units. On the other hand, such cables because of their liability to failure from being run over by cars, locomotives, and other track-operated equipment offer one of the greatest hazards - indeed, probably the worst hazard - met with in the operation and maintenance of permissible equipment. Therefore, the Bureau of Mines is seeking ways of making the use of trailing cables less hazardous.Recently the bureau conducted an extensive investigation of both concentric and duplex rubber-sheathed trailing cables at the Pittsburgh Experiment Station. The results of this investigation were published in two reports.3 4In a larger part of portable motor operations in mines a double-conductor cable can be used. The investigation already mentioned indicated that it is feasible to construct a 2-conductor cable that will stand considerable abuse, such as being run over by loaded cars or light-weight locomotives without producing dangerous arcing in the cable either from grounds or short circuits. There are conditions where more than two conductors are necessary, and in such instances it will probably be necessary to use a cable less resistant to this kind of abuse.Schedule 2C, covering the tests of electric motored equipment, was approved February, 1930. This schedule provides for performance tests on trailing cables as follows;Trailing Cable Performance: The following performance test, optional with the manufacturer, is established for determining the suitability of trailing cables for use on permissible equipment. Trailing cables that pass this test will be especially recommended for this service.The cable will be placed across the two rails of a track and a 4-wheeled 7-ton car will be run over it 50 times. The speed of the car shall be approximately 3-1/2 miles per hour and potential shall be applied to the cable during tests. The cable will be shifted in position after each passage of the car thus giving 100 places over which two wheels have passed. To warrant special recommendation of the Bureau, a cable must neither become short-circuited nor grounded either to the rails or wheels in more than 10 per cent of the 100 places.The Bureau of Mines is prepared to conduct tests as outlined in the foregoing paragraphs to determine the suitability of trailing cables for use on permissible equipment. Application for such tests should be made to the Director, Bureau of Mines, Washington, D. C. Each application should be accompanied by a check for $25.00, made payable to the Treasurer of the United States, to cover the expense of conducting the test on a given size and make of cable."

Apr 1, 1930

By Alice V. Peter

The rare-earth group are among the least familiar of the 92 known elements. Moreover, the relatively few people who have even heard of the rare earths ordinarily regard them merely as very rare elements having unusual names but doubtful commercial application. This typical attitude can be attributed partly to the fact that no commercial uses have been developed for most of the members of the group and partly to the fact that those which do enter into useful articles do so anonymously. Most people speak with a degree of familiarity of the "chromium" plating on their automobiles or household appliances; "antimony" ash trays and cigarette boxes are on sale in many department stores; and "tungsten" lamps and even "molybdenum" steels are advertised in popular magazines. However, the average user of a pocket cigarette lighter is not conscious that the important sparking element is a "flint" made from ferrocerium, and if he does chap on to inquire about the composition he is likely to be told that it is "sparking alloy", "misch metal", or 'pyrophoric alloy." Similarly, the wearer of spectacles made of "Crookes" or other tinted glass probably is not aware that the light softening effects are due to the presence of rare-earth oxides, or that the arc light on his street may owe its brilliance to cerium fluoride in the carbon electrode. Despite a variety of practical applications, however, most of the rare-earth metals still must be listed as scientific curiosities. In fact, little is known as to the properties which may make them useful products at some future date. Meanwhile it is important to note that Nature has been relatively generous in her distribution of the rare earths and that adequate supplies of most of them will be forthcoming when these elements have proved their worth as commercial products.

Jan 1, 1935

By P. H. Francis

In This report, factors which currently enter into the design, manufacture, and quality assurance of explosion-proof enclosures are reviewed, with special emphasis given to the sealing concepts and sealants/cements, per se, for lenses. The physical and mechanical properties of a number of representative sealants and adhesives are measured, and found to exhibit great variance, with few discernible trends which might afford a firm base on which to establish minimum property standards. Accordingly, acceptance criteria for adhesives and sealants are suggested based on the survivability of an explosion-proof enclosure as a structure rather than upon the minimum mat real properties of its constituents. Procedures or surface preparation of adherends, and for quality assurance, also are proposed.

Jan 1, 1980

By Chas. F. Jackson

This circular is an abstract of a manuscript-completed in August 1932, which cannot be published in its entirety due to lack of printing funds. It was originally planned to publish the manuscript as one of a series of bulletins dealing with the mining and milling of ores of the principal metals. Because of the common association of lead and zinc minerals in many ore deposits, and because a considerable proportion of the zinc produced in this country is obtained as a by-product of lead mining or vice versa, it seemed necessary to treat the mining and milling of lead and zinc ores in the same volume.

Jan 1, 1934

By Ernest A. Curth

A 3-month study in 1971 of the Essen Roof Support and Rock Mechanics Research Center's program of roof and support evaluation included 25 mine trips. German miners must adopt mining methods and environmental control measures involving methane drainage and water infusion to improve productivity under severe natural conditions. Pressing problems in ground control must be solved such as cavities in front and above the supports at longwall faces and excessive convergence in gate roads. The Center developed automatic data processing methods to quantify the results of roof and support surveys and to establish criteria. Another approach to ground control is the study of mine models. The Center's laboratory has the facilities to test elements of powered roof support and whole assembled units. Face automation and roof control by powered shields are novel developments that are under close scrutiny in the field as well as in the laboratory. Though the Essen Center's roof and support evaluation techniques are tailored to the needs of the coal mining industry of the Federal Republic of Germany under conditions vastly different from those in the United States, some application may be found here, for instance, monitoring faces and roadways and preventive maintenance of hydraulic systems.

Jan 1, 1974

By Sean Gallagher

The vast majority of ergonomics research has addressed the demands of work in standing or sitting postures, and understandably so. However, many workers (for example, underground miners, aircraft baggage handlers, plumbers, agricultural workers, mechanics, and others) are often required to adopt postures such as kneeling, stooping, squatting, or lying down for significant periods of the work day.

Jan 1, 2005

By Eugene H. Skinner

The U.S. Bureau of Mines conducted experiments on the use of lightweight concrete in the density range of 100 Ib/ft3 for liners in underground mines. Three test sections were completed: a monolithic, portal-type structure with integral walls and arch constructed aboveground; an underground test section constructed in a mine drift using plywood forms; and a second section constructed in a drift using an air-supported formwork. The lightweight concrete in the two underground test sections was placed using piston pumps and a slickline. Fiber reinforcement was added to the concrete in the mine sections without any apparent problems with either pumping or placement of the concrete. In another experiment, the Bureau and Hecla Mining Co., Mullan, rD, used lightweight concrete in the density range of 25 Iblfe to replace timber blocking in a raise preparation structure. Other experiments are described in which low-density, lightweight concrete blocks were produced for mine ventilation doors, stoppings, and barricades. Other mine uses reviewed include pillars and collapsing beams. An advantage of low-density concrete is that it will display up to 50% deformation at a constant yield stress. These hlllovative concepts in deformable concrete lining systems will aid mine operators by decreasing capital and maintenance costs, increasing the available space in underground haulageways, and providing productivity gains and improved resource recovery in the soft, caving, squeezing, or bursting grollnu conditions often found in deep mines.

Jan 1, 1989

By Alfred Bellows

The objective of this contract is to design, build and demonstrate a support system to improve roof control in the entries of longwall mines. The objective of this phase has been the detailed design of such a system and the selection of a test site in which to perform the pilot demonstration. The result is a complete set of detail drawings or specifications which define the three major components of the system. The Gate Support is a variation of a face chock which has an extended canopy and additional hydraulic legs to protect the region of the face-entry intersection. The Entry Support is a steel beam and hydraulic prop set which is reusable and serves to support the first 100 or more feet of entry inby the longwall face. The Transporter is a bolter-like vehicle with a crane used for installing and retreating the beam sets. The test site selected is CF&I's Allen Mine in Colorado. They presently use simi¬lar steel beams and expect the FMA support system to be more effective as well as recoverable. It is recommended that the completed drawings be used to build a prototype system and test it first in a remote section of the mine and then in the active longwall tail entry.

Jan 1, 1978

By Avery H. Reed

RECORD production of marble, kaolin, scrap mica, and talc high-lighted the mineral industry of Alabama in 1962. Among the States, Alabama ranked second in scrap mica, third in the production of bauxite and native asphalt, and fifth in iron ore. The mineral industry of Alabama was dominated by mining and processing of coal and iron ore, and the manufacture of cement, which together comprised 73 percent of the total value of production, compared with 72 percent in 1961. Other important industries were the production of crude petroleum, and stone quarrying. Leading companies were Tennessee Coal & Iron, Southern Cement Co., Southeastern Electric Generating Co., Alabama By-Products Corp., and U.S. Pipe & Foundry Co.

Jan 1, 1963