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By George Saliba

This report disucsses the formulation of a mathematical model for the steering of a conveyor belt by a flat return idler and a troughed idler under various loading conditions. Significant parameters associated with belt training are identified. The generation of a skewed flat return idler model in terms of a steering force and self-aligning torque is presented. Development of the mathematical model for the flat return steering idler is illustrated for the case of no circumferential slip occurring and for the assumption of a bidirectional slip mechanism. Experimental results supporting the theoretical analysis is presented.

Jan 1, 1977

By Verne E. Hooker

This Bureau of Mines report summarizes the results of modifications in the borehole deformation gage design and subsequent changes in the overcoring techniques. Modifications in the borehole deformation gage have greatly improved the creep characteristics and enhanced the versatility of the gage. In situ field tests in competent rock near St. Cloud, Minn., provided sufficient data to compare the reliability between gages and new techniques in obtaining good engineering estimates of stresses. Near-surface horizontal stresses at the test sites are compressive and biaxial in nature.

Jan 1, 1974

This Bureau of Mines report comprises tables listing the name, location, and other pertinent data concerning certain future fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 594 projects for which information is provided, 492 concern coal mines and electric generating plants.

Jan 1, 1976

By David C. Benson

This Bureau of Mines report is an update of IC 8725 and comprises tables listing the name, location, and other pertinent data concerning certain fuel-related projects. The tables include information on projects involving the proposed or planned development of fuel resources, as well as the development of storage, transportation, and conversion facilities; the report covers the 26 States east of the Mississippi River. Of the total 535 projects for which information is provided, 429 concern coal mines and electric generating plants (including Energy Supply and Environmental Coordination Act (ESECA) coal conversion notices).

Jan 1, 1978

By David D. Rabb

A report on location, sampling, assays, mineral examination, amenability leach tests, and evaluation of certain mine dumps in Mohave County, Arizona. Extractions of greater than 30 percent of the gold and silver were achieved during simulated heap leaching of selected mine dump material. Consumption of reagents was relatively low and results suggest leaching of prepared heaps is technically viable and could be economically attractive.

Jan 1, 1980

By A. E. Ketler

A second generation lighting system was installed in the Greenwich Collieries longwall. This report describes the hardware, installation, maintenance, and final results of the program.

Jan 1, 1978

In July 1982 the Committee on Underground Coal Mine Safety completed its study of safety in U.S. underground coal mines; the results of the study were published in the National Research Council report entitled Toward Safer Underground Coal Mines. One of the findings of this study was: THERE IS A STRONG CORRELATION BETWEEN MINE SIZE AND FATAL INJURIES. THE FATALITY RATE IN MINES WITH 50 OR FEWER EMPLOYEES IS NEARLY THREE TIMES THAT OF LARGE MINES (WITH OVER 250 EMPLOYEES), AND ABOUT TWICE THAT OF INTERMEDIATE-SIZED MINES (WITH 51-250 EMPLOYEES). Although the Committee explored possible reasons for the higher fatality rate in the smaller mines, it was not able to explain this phenomenon fully. Therefore the Bureau of mines requested that the Committee undertake a supplementary study of fatalities in small underground coal mines. The Committee met in the fall of 1982, discussed the problem, developed an approach to it, approved a program of statistical analyses, and authorized a panel of four committee members to explore the problem in greater depth. The panel, in turn, reviewed the results of the statistical analyses and met with the president of the National Independent Coal Operators Association and with several owners of small underground coal mines for a detailed discussion of the unique problems of small mines. Panel members examined 66 individual fatality reports prepared by Mine Safety and Health Administration (MSHA) inspectors who investigated fatal accidents that occurred in small underground coal mines in 1979 and 1980. This report is the result of those studies, analyses, and deliberations. The first draft was prepared by the panel, but the report has been reviewed and approved by the entire Committee.

Jan 1, 2011

By Paul M. Tyler

A great variety of substance that differ widely in chemical, mineralogical, and physical properties are loosely linked under the generic term "clay", but for the average man all that matters is whether a given material can be sold or used profitably. So-called "clays" range in texture from true clays and allied minerals that are typically "fat" or sticky to fine sand. Sand and other strictly silicious materials, such as tripoli and diatomite, are not clays in any sense; but many commercial clays are strictly loams, for they are intermediate in texture and always contain a mixture of minerals, though the term "loam" has little commercial usage except in foundry work. Even pure kaolinite, ordinarily considered the typical "clay substance", recently was found to exist as three distinct minerals; and each of these, in turn, exhibits variations in particle size and other physical attributes. Probing with the X-ray and employing other modern tools and techniques, scientists are tracing the patterns of molecules and finding chemical and physical phenomena that seem to disclose the causes for the markedly different behavior of the various aluminum silicates with varying proportions of combined and adsorbed water that are the essential ingredients of commercial clays; but rule-of-thumb definitions and enforced reliance upon empirical tests of actual samples still hold sway. In addition to the hydrated simple silicates of aluminum, almost all clays contain quartz, feldspar, and mica with varying amounts of organic matter and, in addition, other impurities - such as iron, manganese, and titanium oxides - that may discolor them sufficiently to render them unfit for certain important uses. The white clays are generally the purest, but no two clays are really alike, and great care must be exercised to maintain a reasonable uniformity in successive shipments even from the same deposit.

Jan 1, 1938

By Thomas E. Lobb, Harry C. Verakis

This article examines the factors related to injuries due to inadequate blasting shelters and blast area security, and identifies mitigation techniques. The key concepts are:(a) accurate determination of the bounds of the blast area, (b) clearing employees from the blast area, (c) effective access control, (d) use of adequate blasting shelters, (e) efficient communications, and (f)training. Fundamentals are reviewed with an emphasis on analyzing task elements and identifying root causes for selected blasting accidents. Mitigating techniques are presented along with discussions and examples.

By A. S. Peck

This report presents the results of a cooperative study between the Bureau of Mines and the University of Utah to define the mechanism involved in the adsorption of oleic acid and sodium oleate on fluorite, calcite, and barite, using an infrared spectrophotometer for identifying and measuring the adsorbed reagents and reaction products. Fluorite, calcite, and barite react with oleic acid and sodium oleate in a water system, forming chemisorbed and solution products. The chemisorbed species is a surface mineral cation-collector anion salt, Chemical analysis of solution resulting from the adsorption reaction indicates that the adsorption process causes displacement of mineral anions, namely, fluoride, carbon ate, and sulfate from the surface of these minerals.

Jan 1, 1963

By Travis Q. Lyday

Mineral production in Fiji, a group of 322 volcanic islands and atolls of Melanesia in the southern Pacific Ocean, continued to be dominated by gold. However, the Fijian mineral sector remained a minor factor as a source of export earnings, Government revenues, and employment, generating only 1% of the gross domestic product (GDP), estimated as $1.2 billion.2 The largest and most important mining operation was the Vatukoula gold mine on the north side of Viti Levu, the main island. The Vatukoula Mine has been in prduction since 1932, producing about 3.8 million troy ounces of gold and 1.3 million troy ounces of silver to date. In April 1983, the large Australian mining firm, Western Mining Corp. (WMC), assumed operation of the mine in a joint venture with Emperor Gold Mining Co. Ltd., which operated the mine previously. The WMC takeover of the mine management was expected to bring in additional capital and technological expertise in order to modernize operations, increasing both efficiency and output. During the year, rate of recovery was only about 75% of the gold contained in the ore and only 40% of the contained silver. Mining at the Vatukoula Mine was done using bath opencut and underground methods, with about 60% of the ore mined attributed to the underground operations.

Jan 1, 1985

By A. T. Harris

Ground quartzite, known in the industry as amorphous silica, is produced from a quartzite deposit near Honey Brook, Pa., by George F. Pettinos, Inc., of Bala-Cynwyd, Pa. The quartzite is mined by the open pit method and processed in a mill at the mine. The operation regularly produces five standard grades of sand and one grade of crushed stone; however, the company accepts special orders and will produce material to meet the customer's specifications. Beneficiation (chiefly crushing and screening) is controlled by laboratory screen tests on samples taken during preparation of the sand. The chief uses of the sand are for foundry operations, furnace lining, concrete aggregate, and Other specialized uses. The quartzite in this deposit is of uniform composition and does not require control by chemical analysis. However, for special purposes, analysis will be furnished.

Jan 1, 1965

By C. W. Owings, L. D. Tracy

"IntroductionMany bituminous coal-mining companies have inaugurated extensive safety Programs, but the failure to have approved or permissible equipment or safe practice in only one part of a mine has resulted in disaster. The necessity of using only equipment bearing the U. S. Bureau of Mines approval plate is emphasized by the fact that many accidents are the direct result of carelessness on the part of trusted employees using non-permissible equipment. A concrete example is found in the case of an explosion on October 26, 1926, in a mine in the Pittsburgh district, Pennsylvania.Story of the ExplosionAt about 10 o'clock on the night of the explosion an examination was made in No 2 butt left and parallel off 7o. 14 north, and was found to be clear of dangerous accumulations of gas. (See figure). Several hours later a crew of two men brought a self-propelling rock-dusting machine within 50 feet of the face of Po. 2 butt parallel before they examined for gas. The machine operator found an accumulation of explosive gas about 18 inches from the roof. He began to wave his arms thoroughly mixing the gas and air. Undoubtedly a highly explosive mixture was created, and as the men attempted to run the machine back to fresh air an explosion occurred.The helper dropped to the floor and was burned about the face and wrists. The machine operator ran down the entry and was more severely burned about the face, neck, and arms. He later developed pneumonia and died. Both men reached the door in the chute between No. 14 and No. 15 north. A pumper, who had felt the rush of air, found the men and helped them to walk outside."

May 1, 1927

The investigation summarized in this report addressed two primary issues: the determination and use of correction factors, and the development of guidelines for velocity measurement site selection. Other ancillary issues which were addressed include a comparison of measurement methods and devices, aircourse cross-sectional area measurement, and characteristics of mine airways. An exhaustive literature search and analysis was performed; extensive in-mine experiments were conducted; a quantitative analysis of the data was used to develop correction factor tables and site selection guidelines. The reported results of other researchers who have examined the correction factors and site selection criteria, were analyzed in light of the results of this study. The measurement devices included in the experimental phase were: vane anemometer, vortex shedding anemometer, a prototype thermoanemometer, smoke tube, and, oil of wintergreen. The measurement methods include single-point centerline, timed¬-point traverse, continuous traverse for the anemometers, and various distances and cloud positions for the smoke tube and oil of wintergreen devices.

Jan 1, 1983

By S. J. Rodgers

This report presents guidelines on methods of dust control in conventional coal mining operations. The normal mining cycle and equipment used in a room and pillar conventional section are described. Main ventilation, section ventilation and face ventilation are discussed in detail. Proper installation of line brattice, maintenance of proper air flows at the face and split ventilation are stressed. The effects of maintaining the end of the line brattice near the face are described. The advantages and disadvantages of blowing and exhausting face ventilation are presented. The use of water sprays on cutter bars and loading machines is described. The design of a nonclogging water spray system developed under a Bureau of Mines contract is presented. Other methods of reducing dust exposure are discussed and include alternative procedures for shot firing and administrative controls.

Jan 1, 1983

By D. A. Paice

Under the first phase of this contract as reported in the Phase I report it was determined that certain types of commercially available molded case breakers are capable of interrupting mine dc power supplies of nominally 300 volts or 600 volts rating. These circuit breakers incorporate conventional overcurrent trip units but also can be operated by means of low power signals fed to a shunt trip coil. Further development in the Phase I program produced a means whereby a discriminating circuit breaker detector unit could sense the presence of illegitimate loads on the dc electrical system and cause the circuit breaker to trip. The detector unit operated by detecting the presence of 3000 Hz currents which were generated in the illegitimate loads by means of a 12 volt, 3000 Hz signal applied to the dc system. Further development of the program has continued in Phase II with the aim of verifying the practicability of the complete discriminating circuit breaker concept and developing other types of equipments required to implement a system. These other equipments include electronic means for raising the apparent impedance of high power legitimate loads and static filters for smaller loads. The results of laboratory work and limited underground tests have been successful. This report describes the system and the tests that have been conducted on the various equipments that comprise the complete Discriminating Circuit Breaker Concept.

Jan 1, 2012

By Roy S. Nutter

The automation of coal mining must occur in a manner that is economically beneficial to the industry and that enhances the safety of the underground and surface workplaces. The work at WVU over the last five years in applying expert systems and neural network controlled autonomous robotics provides the mining industry with tools that when properly applied should clearly lead to mine-wide management and operational improvements and should also contribute to a higher awareness of safety issues by all work crews. This work includes the development of MMSS (Mine Management Support System) and the detailed development of autonomous robotics utilizing neural networks for mining systems.

Jan 1, 1993

The Hopi Reservation is in Arizona, where coal mining can be traced to the 13th century. Bituminous coal is found in varying quantities throughout the Hopi Reservation. The Hopi Tribe has a 50 percent mineral interest in the coal resources of the joint-use area adjacent to the Navajo reservation. The only coal presently mined on acornrnercial scale from lands in which the Hopi Tribe has an interest is from the Wepo formation at the Black Mesa and Kayenta Mines. These two large surface mines, located over 50 miles northeast of most Hopi settlements, have disturbed more than 6,000 acres. Income from royalties generated by the mines provides significant economic support for the Hopi Tribe. The Office of Surface Mining's Albuquerque, New Mexico, Field Office is responsible for regulating mining and reclamation on Hopi land. The Hopi Abandoned Mine Land Program was approved June 28,1988.

Jan 1, 1992

By J. W. Miller

Depletion of coals most suitable for metallurgical fuel has made necessary a general survey of coking coal reserves in the United States. These investigations were begunn 1948 at the joint request of the Munitions Board, Department of Defense, and a number of coal companies. This report, which is one in a series, by counties, describes the preparation characteristics of the coals of Harlan County, Ky. From these data it is possible to determine: (a) Which coals, either as mined or after beneficiation by conventional preparation, are chemically suitable under present standards for producing metallurgical coke, (b) Which coals require special and more intensive treatment in preparation than is now practiced; and (c) Which coals cannot be considered to be potential sources of metallurgical fuel regardless of preparation.

Jan 1, 1955

By E. O. Binyon

"Corundum and andalusite were discovered in August 1944 on what is now known as the Blue Metal group of claims. The property, comprising five unpatented lode claims, is situated 20 Miles northwest of Yerington in the Buckskin Mining District, Douglas County, Nevada, An engineer of the. Bureau of nines examined the property on November 1, 1944, and recommended a small: amount of drifting and crosscutting to determine more definitely the extent and character of the ore deposit. The work that had been done by the owners was for sampling purposes only and was confined to a few small pits on the outcrop, and no effort had been made. to delimit the ore zone. Samples taken from the best surface showings were sent to the experimental station in Salt Lake City for beneficiation tests. The results of the preliminary test work appeared favorable, and upon the strength of them and the recommendations made by the Bureau, 2.5 miles of access road was approved and completed early in 1945. Exploration was started on June 24 and completed September 26, 1945.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mines resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.This paper is one of many reporting on various aspects of the Bureau of Mines program initiated in August 1939 by passage of the Strategic Minerals act, the scope of which was. greatly expanded by subsequent legislation.Some of these papers were published as war minerals reports, others as bulletins, technical papers, reports of investigations, and information circulars of the Bureau of Mines or• in, technical journals.The Bureau's program at first included separate investigations by the Mining and metallurgical Divisions, but these were consolidated under Assistant Director R. S. Dean beginning July 1, 1942. Mining and metallurgical investigations carried on in three regional organizations more closely integrated thereafter by a staff of specialists, who reviewed findings made in the field and in Bureau Laboratories, considered proposals for additional work, revised reports for publication, and served as advisors to the assistant director."

Aug 1, 1946