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By Foster Fraas

The dielectric constant .has been frequently referred to as an important property in electrostatic separation whore the particles are in an air ambient. Hatfield (1) has studied the problem on the basis of fundamental theory, with the conclusion that separations in air dependent on the differences in dielectric constant, in conjunction with a nonhomogeneous field, are not feasible, because of the low dielectric strength of the air. Although Hatfield has made the statement without showing the calculation or data, calculated values substantiating this under certain conditions of the problem will be given in the following text. However, under other Conditions, these conclusions do not hold, and it is probable that the dielectric constant is indirectly influential.

Jan 1, 1948

By Robert J. Evans

The monorail bridge conveyor (MBC) is a prototype continuous face haulage system that was surface tested and evaluated by the Bureau of Mines. The MBC consists of a series of cascading belt bridge conveyors suspended from roof-supported monorail track. Tests were conducted to determine MBC haulage capability, maneuverability, power consumption, and reliability using rigid and chain-suspended monorail track installations. Subsequent modifications to improve operation and reliability made during surface testing are described. Mining plans were devised to show potential MBC installations for room-and-pillar, longwall development, and shortwall mining sections. Compatibility tests were conducted with the Bureau's prototype hopper-feeder, to provide additional surge capacity and lump-breaking capability. Results from the surface test program, along with modifications to improve system operation and reliability, indicate that the MBC has the potential to perform success- fully in an in-mine trial.

Jan 1, 1987

By D. A. Elkins

This report is the second of a series of three that will evaluate, in order, the metallothermic, carbothermic, and electrolytic methods of magnesium production. The historical development of the carbothermic process is outlined. Production costs varying from 38.9 to 21.8 cents per pound of magnesium are estimated for different versions of the process. Additional suggested process modifications are listed. The technical and economic potential of the different versions are compared. Areas deemed most promising for future research on the process are delineated.

Jan 1, 1967

By Jack L. Henry

A laboratory and a pilot-plant-scale investigation has been conducted by the Bureau of Mines to examine possible sources of nitride defects in the production of magnesium-reduced titanium sponge. The production of alpha-stabilized nitride inclusions in hot-rolled titanium plate from air contamination of sponge during its manufacture has been experimentally demonstrated. Magnesium-reduced sponge prepared from air-contaminated magnesium or when contaminated by an air leak during reduction, vacuum distillation, or inert gas sweep, shows very large variations in nitrogen content. Refractory nitrides, delta TiN and epsilon Ti2N have been identified in this sponge. The highest incidence of inclusions resulted from sponge that was reduced by air-contaminated magnesium and from sponge subjected to air contamination during the vacuum distillation cycle and during helium sweep. Air contamination of sponge during the reduction cycle was not nearly as effective in producing inclusions. Tests showed that color and texture may not be reliable criteria for locating defects during sponge inspection. Maintenance of good vacuum-tight integrity, filtration of molten magnesium prior to charging into the reduction retort, and mechanical attrition of sponge to pulverize and disperse nitrides are suggested as practices to lower inclusion incidence in commercial titanium ingots.

Jan 1, 1974

By Frank E. Cash

Data on the occident experience of the pebble-phosphate industry in Florida for 1937 and 1938 are combined in this report with statistics for the 7-year period 1930-36, inclusive, which were published in Information Circulars 69174/ and 69685/. The periodic publication of such data enables the pebble-phosphate industry, as well as other industries, to consider relative hazards, compare experience, and thereby help to prevent accidents. ACKNOWLEDGMENTS Accident data ere furnished by the following; operating companies: Amalgamated Phosphate Co., Brewster; American Agricultural Chemical Co., Pierce; Coronet Phosphate Co., Plant City; International Agricultural Corporation, Mulberry; Phosphate Mining Co., Nichols; Southern Phosphate Corporation, Bartow; and Swift & Co. Fertilizer Works, Bartow.

Jan 1, 1940

By William Seymour, L. D. Schmidt

"FOREWORDAmong many problems created by World War II, the question of supplies and distribution of raw materials is of outstanding importance. One of the most critical of these raw materials is fuel, and of the fuels coal is of primary importance. The normal consumption of coal has increased greatly owing to the increased tempo of industry in general. It has been necessary to divert much of the fuel oil, gasoline, etc., ordinarily used for industrial and domestic purposes, to supply the enormous demands of mechanized warfare. Coal must be provided to replace this fuel. Furthermore, the enormous increase in the production of steel has increased the demand for coking coals to a critical point.The Solid Fuels Administration for War is encouraging the use of anthracite fines in the production of byproduct coke for blast furnaces for three reasons. First, the production of anthracite for domestic use; is hampered by the inability to find a market for the fines incidental to the production of domestic sizes. Second, the shortage of low-volatile coking coal is acute, and any action that will decrease the quantity of low-volatile coal required will relieve the situation. As will be seen in this report, there is some promise that use of anthracite fines in coke-oven mixes will lower the amounts of low-volatile coal required. Third, utilization of those anthracite fines will tend also to alleviate the general fuel shortage. It has been the privilege of the Bureau of Mines to cooperate with the Solid Fuels Administration in the technical problems involved."

Apr 1, 1945

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

The purpose of this investigation was to develop a wide variety of columbium and tantalum alloys and to determine their suitability for use at elevated temperatures . Sixty - nine columbium and tantalum alloys were investigated . For this study , columbium was alloyed with two or more of the following : nium, tungsten , vanadium , titanium, and zirconium . Tantalum was alloyed with vanadium or hafnium, or hafnium and carbon . The fabricability was determined by an arbitrary procedure . Hardness measurements , elevated - temperature tensile properties , and oxidation- resistance studies were made . Of the alloys studied , Cb - 15 Hf - 5W, Cb - 15Hf - 5W- 10Ti , Cb - 15Hf - 10W- 10Ti , Cb - 10V - 5W, Ta - 30V , and Ta - 20 to 33Hf exhibited excellent high - temperature properties . These alloys were not only easy to fabricate , but they also had good oxidation resistance and excellent high- temperature strength .

Jan 1, 1964

By R. H. Fernald

In 1900, as far as available records show, there were only two producer-gas power installations in the United States. In June, 1915, the number probably exceeded 1,000. Of this number, some 84.5 per cent comprised small plants using anthracite, and only about 15 per cent of the total number utilized bituminous coal and lignite. In addition to these, two plants used wood, and three or four used oil. In the main, however, the larger sized units are operating on bituminous coal and lignite.

Jan 1, 1916

By CLARENCE G. SMITH

Prior to the actual development of an oil property it is difficult to determine the quantity of oil under the property and the rate at which this oil can be brought to the surface-factors that determine the ultimate value of the property. Consequently, there has been much confusion in devising accounting systems that, during the entire life of a property, will show costs and profits from which the producer can determine whether his property is being worked at a profit or otherwise. The Bureau of Mines publishes this report in recognition of a distinct need for a simple treatise on accounting methods adapted to the peculiarities of the petroleum industry. Probably many companies operating oil wells are not fully acquainted with details important to the welfare of their business, because their account books fail to furnish them with exact and adequate data. With the accountant rests the responsibility of providing the management with reports setting forth the details of the business expressed in fitting terms as well as in dollars and cents. These reports are a means whereby efficiency may be maintained, waste prevented, oil obtained and sold, and money suitably reinvested. They also enable a concern to study the progress of its business in order to conserve to the utmost the possible benefits from an exhaustible deposit of mineral wealth. When managements realize the extent of the waste at their properties more attention will be given to the character of the accountancy records. Herein are presented descriptions and discussions of balance sheets, profit-and-loss statements, and bookkeeping methods peculiarly adapted to the oil business. As far as possible, technical phrases have been omitted in order that those not familiar with accounting terms may be able to follow the subject matter. The systems of keeping books outlined in Chapter X have all been found practical. For brevity as well as clearness the major part of the work refers to the company operating only one property.

Jan 1, 1917

By Stephen M. Jasinski

The development and industry adaptation of advanced technologies have led to many important uses for bismuth and its compounds. Bismuth-base alloys are essential for manufacturing jet engine turbine blades, lenses, and various safety devices, such as fire-protection sprinklers. The addition of bismuth to iron, steel, and aluminum imparts properties to these metals that makes them useful in diversified applications. Bismuth is also used widely in medicine, pigments, and electronics. The United States relies heavily upon imports from South America and Europe to meet its demand for bismuth, which is recovered chiefly as a byproduct of lead processing.

Jan 1, 1992

By Hillary W. St. Clair

The purpose of this investigation was to determine the practicability of refining crude aluminum-silicon alloy or aluminum scrap containing silicon and iron by selective dissolution in zinc of the aluminum from the alloy followed by distillation of the zinc from the aluminum.

Jan 1, 1949

By G. K. Derby

The Bureau of Mines investigated methods for removing dragline bucket wire rope terminations with the objective of finding efficient methods that are safer than the method most commonly used at U.S. surface mines, which is to use the explosive impact of a projectile fired from a cannon to remove the rope termination. Removal of a wire rope termination for repair or replacement requires separation of the wedge and socket that lock together to secure the rope end. The Bureau investigated currently used methods and improved upon and tested two safer alternate methods for removing wire rope terminations. A cannon test program was conducted, using 40-and 50-gr primer (detonating) cord, to establish the possible force produced with a 4-in-bore cannon and a 55-lb projectile. Wedge and socket units supplied from cooperating mines were separated under controlled conditions to establish data on separation force requirements. The two alternate methods investigated were use of the force generated by (1) a pendulum ram and by (2) a portable hydraulic pusher. Both methods are capable of providing sufficient force to effect wedge and socket separations on draglines with up to 78-yd3 buckets under normal conditions.

Jan 1, 1984

By GLADYS G. HEFFNER, William H. Waggaman, Edwin A. Gee

Thallium is one of the rare and relatively neglected elements that has recently assumed conspicuous importance. This element is widely distributed in nature but occurs in such minute quantities in most rocks and minerals that its recovery at present is only commercially feasible as a byproduct of other industries. World War II, with its unprecedented demand for products having special or unusual properties, led to a study of a number of the rarer elements that previously had been given comparatively little attention for one or more of the following reasons: 1. 2. Limited knowledge of properties. Small quantitios present in available raw materials. 3. High cost of concentration and recovery. Some of those rare elements, either alone or in the form of compounds, have already proved of such value for certain military and industrial purposes that their extraction from ores and waste products, oven at high cost, is fully justified. On the othor hand, further investigation of their character- istics, discovery of more adequato sources, and improvement in methods of con- centration and recovery would greatly broaden their field of usefulness and establish new and expanded industries. The current market for some of these elements exceeds the available supply. One of the functions of the Bureau of Mines is to study the properties of such elements in greater detail, locate the most promising raw materials from which they can be derived, and work out methods of extraction that will render the recovery of such elements more economical. The purpose of a serios of information circulars on the raror elements is to present in condensed form the facts and data so far available. This information may serve as a basis in planning more complete investigations loading to a full utilization of such elements.

Mar 1, 1950

1.0 SCOPE AND REGULATIONS 1.1 This specification covers the minimum requirements for material handling and associated equipment including design and materials. 1.2 This specification requires compliance with all federal, state, local laws and regulations which may be applicable including the Occupational Safety and Health Act, Construction Safety Act as well as rules, regulations and standards of the Secretary of Labor.

Jan 1, 1979

By Guenter F. Lehmann

This report summarizes the results of the development and testing of a prototype monorail suspended bridge conveyor (MBC) system as a method of continuous haulage In underground mining applications. Included are the results of full scale, surface and underground testing of the complete MBC system. Conclusions drawn from these results, together with recommended modifications, supports the viability of the MBC system.

Jan 1, 1988

By Daniel Harrington

On the night of June 8, 1917, the flame of a carbide lamp accidentally set fire to the uncovered and frayed insulation of an armored power cable near the 2,400-foot level of the North Butte Mining CO.'s Granite Mountain shaft. How this, insulation accidentally became exposed is explained on page 15. The highly flammable oiled fabric set fire to the shaft timbers, and as this is a downcast shaft the fire spread with great rapidity, soon filling the mine workings with smoke and gas. At the time 410 men were working underground, 247 of whom escaped by various means, but most of the 163 remaining were probably overcome soon after the fire started, and perished. Only two men were actually burned. The cause of the disaster was purely accidental. The immediate effect was the unexpected reversal of normal conditions; the ultimate effect was great loss of life and the destruction of the main hoisting shaft, putting it temporarily out of service. The work of rescue and fire fighting continued eight days. The following pages present an attempt to draw some practical conclusions and suggestions from this disaster. The property of the North Butte Mining Co. consists of about 220 acres in the northeastern part of the Butte district, Montana. Next to the Anaconda Copper Mining Co. it is the largest producer of the district. In 1916, the year before the disaster, there were 1,160 men employed. The output was 560,947 tons of ore, which yielded 24,498,181 pounds of copper, 1,047,063 ounces of silver, 1,712 ounces of gold, and 412,953 pounds of zinc. The profit was $2,479,595. The total development work for that year was 21,694 feet. During the first half of 1917, the year of the accident, the daily tonnage of ore averaged 2,000, an increase of 400 tons over that of the year 1916.

Jan 1, 1922

By H. H. Schrenk

One phase of Bureau of lines work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective devices. To insure that devices embodying these features will be available the Bureau has established schedules of minimum requirements for oxygen breathing apparatus, gas masks4/, supplied-air respirators (hose mask, air-line respirators, and abrasive blasting helmet hoods, or masks)5/, and dispersoid (dust, fume and mist) respirators6/. Approval test, of oxygen¬-breathing apparatus are conducted by the Safety Division; approval tests of other types of respiratory protective equipment are conducted by the Health Division. These divisions comprise the Health and Safety Branch.

Jan 1, 1941

By Sathit Tandanand

Horizontal displacements and ground strains induced by mine subsidence are significant information needed for calculating damage and developing precautions against subsidence effects on surface structures. To devise a simple method for determining the surface horizonal displacements and strains simultaneously with the subsidence prediction, the U.S. Bureau of Mines examined the significance of the tilt number, which is the proportionality constant in the relationship between the horizontal displacement and the slope of the subsidence profile. The ratio of the tilt number to the critical radius of the subsidence trough is identical to the ratio of the maximum possible horizontal displacement to the full subsidence, which is found to be constant in most European coalfields. If this ratio is known for a particular minesite in the United States, then horizontal displacement and ground strains can be readily obtained from the primary subsidence data.

Jan 1, 2010

By John P. Wagner

The details of a three-phase study (total time period of 12 months) entitled ?Fire Alert Systems for Metal and Non-Metal Mines,? are presented. Phase 1 consists of a state of the art survey on fire detection devices and gas sensing techniques. Phases 2 and 3 include laboratory screening and systems concepts testing on various detectors classified as products of combustion, optical view-field and contact (or thermal) types under incipient and flaming combustion conditions. Recommendations for a mine fire detection system to protect shaft, sealed off or mined out (from spontaneous combustion of sulfide containing ores and cellulosic materials), and fuel storage areas are also included. me principal problem area noted during Phase 1 study is the high expected occurrence of false alarming of products of combustion detectors (POC") subjected to normal mining operations---diesel vehicles and equipment and shot firing or blasting operations. Simultaneous gas sensing of either the ratio of CO/NOx or CO2/NOx with detection of one or more fire signatures (smoke, radiant energy, or heat sensing) is the recommended approach to discriminate against these operations.

Jan 1, 1975

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