Search Documents

By Mark Sheppard

This paper is the third of a series recording the results of tests made at various quarries throughout the United States to determine (1) the relation between the size gradation of feed to, and product from, primary crushers, (2) the particle shape of the crushed. product, (3) the differences in gradation and particle shape produced by different types of primary crushers, and (4) the differences in gradation and particle shape caused by crushing different kinds of stone. Progress reports 1 and 2 dealt with comparisons of different types of crushers crushing the same type of stone. This report deals with relation¬ship between feed and product of two different limestones, as to size distribution and particle shape, when crashed in the same crusher.

Jan 1, 1938

By John D. Foulkes, David A. Curtis, Robert L. Lagace, John L. Rothery

An investigation is made of the feasibility of developing compact transmit antennas and/or other means to efficiently couple VLF to MF band radio energy between portable wireless communication units in coal mines. The completely wireless communication ranges between two portable radios equipped with practically-sized reference loop antennas in representative coal mine environments are estimated. Antenna technology is assessed with respect to transmit moment, range, intrinsic safety, battery and wearability requirements to deter- mine the most suitable antenna types for use by miners. It is concluded that air-core bandolier loop antennas, and perhaps ferrite-loaded loop antennas, having peak transmit moments of about 2.5 ampere-m5 will be the most effective antenna choices for portable units. This choice, however, will not allow the range goal of 1350 feet to be attained in mines having unfavorable signal attenuation and noise environments. Rectangular air-core loops are compared with grounded horizontal-wire and vertical-wire mode exciters for fixed station applications. The potential for significantly increasing the wireless communication range by inductively coupling to communications and power lines in a mine is evaluated and found to be considerable based on theoretical coupling equations. Lastly, the theoretical performance of a hybrid noise cancelling diversity receiving technique that utilizes both the electric and magnetic field components of the ambient noise to improve the receiver output signal-to-noise ratio under certain adverse conditions is estimated and shown to be favorable when the magnetic and electric field noise components are highly correlated.

Jan 1, 1977

By V. F. Parry

Under the present emergency every consumer should store as much coal as he can. Although there is no shortage of coal, there is likely to be a shortage of labor to mine excessive quantities in the fall, and railroads cannot be expected to deliver coal promptly on account of the need for transporting war materials. Some miners must join the armed forces, and those who are left may be unable to mine coal as rapidly as you will need it when winter comes. When the first cold days arrive, there may be a shortage of trucks to deliver coal. Deliveries may be planned in advance, and your turn might not come until it is too late.

Jan 1, 1942

By Richard L. Jenkins

Systematic sampling, in reconnaissance fashion, of the continental shelves of the United States to define favorable areas of offshore mineral deposits, is one of the long-range marine mineral; programs of the U.S. Department of the Interior. In mid-1966 the Department of the Interior launched its Heavy Metals Program to stimulate domestic output of gold which is in serious short supply. The program is jointly conducted by the Geological Survey and the Bureau of Mines.

Jan 1, 1968

By S. J. Broderick

[The term "nonmetallic minerals,? as commonly used in the mining industry, refers to those minerals of industrial importance that are mined essentially for uses other than for the metals contained. The field comprises several hundred minerals of industrial importance, of which 70 have been adequately described in the textbook Industrial Minerals and Rocks.3/ A few of the more important nonmetallic products are sand and gravel, salt, phosphates, clays, refractories, linestone, and cement materials. Some of tic minerals, such as bauxite and pyrolusite, have both metallic and nonmetal is applications, but in this report only the nonmetallic mineral phases are considered. In the organic field of nonraetallics only coal is considered, as, the, others - petroleum, natural gas, natural bitumens, and hydrocarbons - are of no importance in water softening.]

Jan 1, 1941

By Martin H. Stanczyk, I. L. Feld

Continuous open - circuit attrition grinding of a coarse commercial kaolin to produce paper - coating clay , which must have a particle size analysis of 70 percent or more minus 2 - micron equivalent spherical diameter ( esd ) , was studied by the Bureau . The coarse clay , containing about 11 percent minus 2 -micron esd material , was ground in a 10 - inch- diameter attrition grinder using continuous single- and multiple - stage grinding circuits . The clay feed rates varied from 10 to 480 pounds per hour . In some tests , the influence of varying loads of sand grinding media on particle size reduction was studied . Batch grinding tests also were made for comparative purposes . Multiple- stage grinding gave better results than single - stage treatment when equivalent raw clay feed rates were used . In the best test made , a product containing about 80 percent minus 2 - micron esd material was obtained when grinding 60 pounds of raw clay per hour using a three - stage grinding circuit . Power consumption in the test was about 318 kilowatt -hours per ton of clay treated or 475 kilowatt - hours per ton of minus 2 - micron esd material produced .

Jan 1, 1963

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

By John Durkin

Electromagnetic narrow-band signals were transmitted through the earth at 27 coal mines located throughout the United States. From those Bureau of Mines tests, apparent earth conductivity values were derived based upon a homogeneous half-space model of the earth. The derived conductivity values were found to be inversely proportional to the transmitted frequency and mine depth. A linear regression model relating the logarithm of the conductivity to the mine depth was formulated, and the results indicate that the mine depth can be an adequate predictor of the apparent earth conductivity above coal mines. Apparent earth conductivity was found to decrease with mine depth.

Jan 1, 1984

By Joseph B. Cummings

The Twin Buttes camp embraces eight mines in the Pima mining district. The first mining claims in the camp are said to have been located in 1876, but little mining was done until 1905. Intermittent operation of five of the mi.nes to 1928 yielded 388,231 tons of ore averaging 6.19 percent copper and 8 small tonnage of high-grade oxidized zinc ore. While the Bureau was investigating the area, one mine was active, and it started to produce in 1944. The mines of the Twin Buttes camp are at or near contacts of intrusive granite with Paleozoic limestones and quartzite. The ore shoots lie in metamorphosed sediments adjacent to a zone of garnet rock that separates the ore from the footwall granite. Small fissures that originate at the contact and cut the sedimentaries appear to have been controlling factors in ore deposition. No important ore bodies are exposed at the surface, and those developed wore discovered by sinking on the fissure veins to the contact zone. Most of the area overlying the favorable ore zone is covered by alluvium ranging in thickness from 5 to more than 20 feet.

Jan 1, 1950

By Laird Crocker

This report describes a study of beryllium recovery from sulfate leach liquor by di-2-ethylhexyl phosphate (EHPA) solvent extraction in conjunction with caustic stripping. The work was one phase of Bureau of Mines research on process development for Spor Mountain, Utah, ores. Solution for the solvent extraction studies was prepared by sulfuric acid leaching of ore containing 0.6 pet BeO, Before solvent extraction of beryllium, the leach liquor was treated to prevent coextraetion of iron by either (1) removal of ferric iron by amine solvent extraction or (2) reduction of ferric iron to nonextractable ferrous iron by treatment with sulfur dioxide. Beryllim was extracted from the aqueous leach liquor by countercurrent multistage contacting with a kerosine solution of EHPA. The loaded organic solution was stripped with sodim hydroxide solution. Subsequently, beryllium hydroxide was precipitated by boiling the sodium beryllate strip solution and converted to beryllium oxide of 98 pct BeO-grade by calcining. Material of this grade can be directly processed into beryllium-copper alloy or be used as starting material for further refining to produce high-purity, nuclear-grade beryllium. Over 90 pct of the beryllium contained in the leach liquor was recovered as beryllia.

Jan 1, 1963

In order to reduce waste and improve resource conservation, mine planning, and development, the U.S. Bureau of Mines is investigating the effects of multiple seam interactions associated with longwall coal mining. Field investigations were conducted at a mine located in Boone County, WV, where a longwall panel was operating subjacent to room-and-pillar workings in an overlying seam. To assess the effects of overlying workings on longwall headgate stability, the Bureau gathered various geotechnical information at this minesite. Headgate pillars and entries were instrumented and monitored to study their behavior during side-abutment loading as the longwall panel approached and passed beneath the overlying room-and-pillar developments. The two operations are separated by 800 ft of interburden, and although interactions between operations separated by this distance are uncommon, geomechanical measurements indicate the occurrence of an interaction. These measurements show that convergence on the headgate entries was most adverse subjacent to barrier pillars in the overlying mine. Pillar measurements indicate that side-abutment pressure increases were slightly greater than predicted values. Several factors related to both geology and mine design, believed responsible for this large interactive distance, are discussed.

Jan 1, 1990

By Mark Sheppard

This paper is the third of a series recording the results of tests made at various quarries throughout the United States to determine (1) the relation between the size gradation of feed to, and product from, primary crushers, (2) the particle shape of the crushed product, (3) the differences in gradation and particle shape produce- by different types of primary crushers, and (4) the differences in gradation and particle shape caused by crushing different kinds of stone. Progress reports 1 and 2 dealt with comparisons of different types of crushers crushing the seine tyre of stone. This report deals with relationship between feed and product of two different limestones, as to size distribution and particle shape, when crashed in the same crusher.

Jan 1, 1938

By Raja V. Ramani, Robert L. Frantz

"In response to the U.S. Bureau of Mines (USBM) Request for Proposal (RFP) for "" the establishment of a Generic Mineral Technology Center (GTC) in Respirable Dust,"" the Mining and Mineral Resources Research Institutes (MRIs) at The Pennsylvania State University (PSU) and West Virginia University (WVU) in association with participating MRIs at Massachusetts Institute of Technology (MIT), and the University of Minnesota (UMN) have prepared the comprehensive research program described herein. Michigan Technological University (MTU) joined the Center as an affiliate after its inception. This program was developed with recognition of the stated objective of the Federal Mine Safety and Health laws which is to "". . . permit each miner the opportunity to work underground during the period of his entire adult working life without incurring any disability from pneumoconiosis or any other occupation-related disease . . . .""Exposure to respirable contaminants in mine atmospheres has long posed a serious hazard to miners. The control of these hazards, some of which can have sudden and catastrophic consequences and some others, slow and long enduring, has been a major concern for labor, management and the government. This concern has manifested itself in four mechanisms of control -- (1) regulatory control through minimum standard setting by the passage of mine health and safety laws, (2) engineering control through design and operation of mines according to the best recommended practices, (3) interaction of dust and lung control through periodic physical examinations, wearing personal protection devices, etc., and (4) legal and social control through workman's compensation laws for occupation related health deterioration."

Aug 31, 1989

By Lawrence G. Houk

Monazite sand is the only commercial source of cerium, other rare-earth metals and thorium. Although used in rather small quantities, it is essential to many industries. The United Unites is entirely dependent upon British India and Brazil for its supplies. Monazite sand or sand imported under the tariff classification for monazite was shipped to the United States in greater quantities, in 1940 than ever before. About 75 percent of our imports was from British India and most of the remainder from Brazil. If need be, Brazilian production can be expanded to supply all of our essential requirements, and the theater of war expands in the Pacific Brazil may supersede India as the principal source. PHYSICAL PROPERTIES The mineral monazite is generally honey yellow or may vary from greenish yellow to clove brown. The grains are small and resinous in luster, and range from subtranslucent to opaque. The specific gravity varies

Jan 1, 1943

By A. W. Ambrose

"Introduction.Oil-field operations have often been carried on under great stress and haste, in which the prime purpose has been to put the wells down rapidly as possible, without regard to a few of the various factors affecting cost. In such fields as Burkurnett, Texas, where the well locations are town lots and other small tracts, the operator was concerned primarily with in drilling. In such cases a few thousand dollars more or less in the cost of a well not considered. We are reaching a time, however, when our reserves a,more definitely outlined and properties are being along more economic lines. Operators are becoming more concerned with the actual cost of this work, and are gradually learning that fuel consumption can be reduced in drilling and producing without delaying the speed of drilling, and in the case of production, it will greatly reduce the unit cost per barrel of production.Types of Field Boilers.In the oil fields there are in general two types of boilers; those which are used for drilling wells and are of a more or less portable character, and those established later in a more permanent form and serve for the purpose,of generating steam for producing the oil. As a rule, the latter type of boilers are larger than those of the drilling type. Usually, little care is given to the installation of drilling boilers; particularly in attempting to set them up in such a way as to avoid waste in of fuel. Because of the temporary nature of these installations there may be some justification for not giving them more,attention in this resend, but it is believed that a few precautions could be taken that would amply repay the cost and trouble taken. In connection with the boiler plants that are afterwards established, when a few producing wells have been,brought in with a life of two to ten years and probably longer, much care to the boiler-plant construction and to the installation of recording instruments which will assist in operating the plant at minimum cost."

Nov 1, 1920

By E. Morrice

Gadolinium, dysprosium, and yttrium are difficult to electrowin as high-purity liquid metals because of their high melting points (>1,300° C). Samarium metal is difficult to prepare directly by electrolysis because the metal reacts with the electrolyte. In this Bureau of Mines study, the rare-earth metal was electrodeposited on a solid manganese, chromium, or iron cathode to form a low-melting alloy. The alloy was then vacuum distilled to separate the rare-earth metal from the ferrous metal. A typical samarium metal product, obtained as the distillate from vacuum distillation of a samarium-iron alloy, contained 150 ppm oxygen, 80 ppm carbon, and 50 ppm iron as impurities, Gadolinium metal, obtained as a residue from the distillation of a gadolinium-chromium alloy, contained 300 ppm oxygen, 200 ppm carbon, and 100 ppm chromium.

Jan 1, 1969

Despite the strange names given to its parts, the eye is not a very complicated organ. If you think of the eye simply as a detector of light, you will be able to understand the mechanics of central vision, peripheral vision and adaptation described below. These three processes of seeing are basic, not only to mining, but also to everyday activities. A number of simple experiments are described In this chapter to demonstrate different types of seeing processes. Try the experiments. They really make the point. Light rays reflecting from objects enter the eye through a lens and fall on the back surface called the retina. The retina 1s lined with millions of tiny light sensors called "rods" and "cones." These sensors, in turn, are connected to the brain by the optic nerve.

Jan 1, 1976

By A. G. Starliper

The report covers studies by the Bureau of Mines on the removal of metallic values in two waste products from the Longhorn tin smelter at Texas City, Tex. One product was a slag that contained tin, tungsten, iron, tantalum, and columbium. The other product was a spent acid solution that contained tin, tungsten, iron, lead, copper, zinc, and silver and that came from presmelting treatment of impure tin concentrates. Molten slag was treated with sulfur or sulfur compounds and with coke, calcium carbide, or gaseous reductants to form tin sulfide that volatilized from the charge and to reduce tungsten along with iron and silicon to form a carbon-bearing metallic layer. The metallic layer was treated by an oxidizing alkali roast and then was water-leached to extract the tungsten. The waste acid was used in other experiments to dissolve an iron-tin- tungsten alloy (hardhead) obtained by direct reduction of the slag. An insoluble fraction containing tungsten, silver, silicon, columbium, and tantalum was removed, and copper was cemented on metallic iron, Tin was recovered by cementation on zinc plates, and lead was precipitated by adding sulfate ion. Iron was precipitated by increasing the pH which left a solution containing principally zinc. Slabs of hardhead were electrolyzed in an electrolyte consisting of waste acid to plate out groups of metals at different pH?s. The time did not permit thorough exploration of this method of treatment.

Jan 1, 1962

By R. W. Stahl

A survey of firefighting facilities and practices in coal mines conducted by the Bureau of Mines3/ showed such variations in equipment and apparent attitude toward fire protection that a comparison with other industry seemed advisable. Although other industry is confined generally to surface operations and the hazards probably are not as great, the same general methods of extinguishment are employed, so that the cost and protection at least should be comparable. An investigation of industry other than mines revealed a generally greater emphasis placed on fire-combating equipment, fire-brigade training, fire-fighting facility inspection, and fire-hazard elimination, as well as a greater average expenditure for fire protection.

Jan 1, 1959

By M. J. Brnich

The purpose of this U.S. Bureau of Mines study was to assess the ability of trainees to don an unfamiliar self-contained self-rescuer (SCSR) after having become familiar with how to put on a different type of apparatus. Prepractice instruction was the same for all individuals learning to put on a device: a step-by-step, hands-on talk-through using the "3+3" method. Subjects were assigned to groups that had their initial donning instruction delivered on either the Draeger OXY-SR60B or the CSE SR-100. Trainees' performances were then evaluated using the other model. Donning trials were analyzed using a number of measures. It was found that SCSR design had a moderate influence upon how well the donning task transferred.

Jan 1, 2010