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By J. R. Sweet

The paper describing the raining operations at the Mt. Hope mine, Mt. Lope, N. J., is one of a series being prepared by the United States Bureau of Mines on mining methods, practices, and costs of various mining operations in the United States. Mt. Hope mine produces magnetite ore. It is situated in the general northern part of the State of New Jersey. The towns of Rockaway, Wharton, and Dover lie within a radius of 4 miles from the mine. Dover is 40 miles from New York City.

Jan 1, 1932

By Kenneth M. Smith

The kaolin deposits of Aiken County, South Carolina (fig. 1), have been worked continuously since 1852. It has been long known that the deposits contain a high percentage of' alumina and that large reserves exist. These facts led to the early selection of' this area for examination in the search by the Bureau of Mines for high-alumina clays. An exploratory program was started by the Bureau, and drilling was carried on from. June 27, 1942, to October 31, 1942. The kaolin-bearing district occupies an area approximately 25 miles long and 11 miles wide, running northeast, with its center at Aiken, S. C. (fig. 1). Within this district, a triangular area bounded by Horse Creek, Silver Bluff Road, and Hamburg Road was roughly prospected by boring 43 machine and 12 hand holes. As a result of the data obtained, a final smaller area was chosen for more systematic prospecting. This area is bounded by Pine Log, Tewkesbury, Silver Bluff, and Craig Sawmill Roads and covers about 4,000 acres. Mineral exploration agreements covering 11,272 acres were signed by 35 property owners, and 11,956 feet was drilled in 200 holes on these properties.

Jan 1, 1949

By W. W. Roepke

The linear cutting system, developed by the U.S. Bureau of Mines, uses geometric principles developed by Cardan to produce a nearly constant cut depth. The new system has been extensively tested in a synthetic material under laboratory conditions to verify mechanical capability and to identify operational characteristics. Comparisons between 15-rpm linear cutting and 50-rpm rotary cutting systems show significant improvement in respirable dust entrainment, product size distribution, and energy usage. Respirable dust is reduced by as much as 90 pct. Recovered product showed a 67-pct reduction in -0.32-cm (-1/8-in) material and a 200-pct increase in +5.08 cm (+2 in) material. Average power was reduced by 66 pct for the linear cutting. Because the bit cutting paths differ between linear and rotary cutting, it was necessary to compare the two at the same cut depths and bit types. These comparisons show that low revolution per minute rotary cutting entrains about the same amount of respirable dust as the linear cutting system, but the average shaft torque may be 55 to 130 pct greater for the rotary system.

Jan 1, 2010

By Charles T. Holland

ANALYSIS of 117 occurrences of bumps in coal mines shows that 67.6 percent are associated with pillar-line points.4 Slabbing and splitting pillars, development, and other unfavorable milling practices in abutment areas may be a contributory or the primary cause of bumps. The cure for pillar-line bumps is to recognize areas that can be expected to become highly stressed and to project the mining plan and operations to eliminate such areas insofar as possible. If such areas cannot be eliminated, then the mining plan and operations should be projected to avoid the necessity of disturbing these areas before the stresses have been dissipated.

Jan 1, 1954

By W. J. Wiehagen

The Work Crew Performance Model (WCPM) seeks to define performance variability within similar tasks of an underground work crew and relate observed variability to a cost consequence. Performance variability is described using work site observations to determine the adherence to job elements con¬tained within a standard operating procedure. Key components of the WCPM include (1) job definition through task analyses and the ranking of job elements by perceived cost consequence, (2) observational techniques for establishing performance baselines by measuring adherence to safe and proficient job procedures, and (3) cost linkages between adherence to task procedures and measures of consequence for noncompliance. Data presented within this report were obtained through the study of shuttle car operation in an underground mine in Appalachia. Observed adherence to safe and proficient job procedures by opera¬tors matched well with the consensus profiles (measured through a nominal group technique) with min¬ing personnel. It was also found that experienced operators consistently outperformed less experienced, incidental operators. These findings imply potential use of the WCPM as a practical procedure for thinking systematically about the choices available to reduce performance variability. Field application of the model can offer useful data to evaluate training and financially support performance improvement strategies that can be tested for their ability to reduce human error.

Jan 1, 1994

By M. B. Boyer, C. H. Herty, F. A. Hartgen, G. L. Frear

"DEFINITION OF VISCOSITYViscosity has been defined as the resistance experienced by one portion of a liquid moving over another portion, such as one molecular plane moving over an adjacent plane. A measure of viscosity is the force required to keep one plane in motion at Unit velocity, the other plane being considered stationary. Figure 1 illustrates the general idea that the surface friction between two adjacent areas will be greater the larger the molecules. Therefore it may be assumed that viscosity will be increased by molecular association or agglomeration, and likewise dissociation rill decrease viscosity. According to Maxwell (1)6 the unit of viscosity, the poise, is the tangential force per square centimeter of area of either of two horizontal planes 1 centimeter apart, one of which is fixed while the other moves with unit velocity, the space between being filled with viscous liquid of unit viscosity.The need for a satisfactory apparatus and experimental procedure for the determination of viscosity of high-melting materials at temperatures corresponding to those in pig-iron and steel making has been recognized during the past few decades. The condition of the slag during the smelting and refining periods in the iron- and steel-making processes exerts an important influence on the metal product obtained, this slag condition really meaning the state of viscosity or, vice versa, fluidity, which the slag attains under certain conditions."

Jun 1, 1934

By Howard J. Pincus

The purpose of the study is to investigate the effects of fracture fillings and associated alteration on the mechanical behavior of rocks. Experimental results are presented for 98 specimens from the Climax mine, which were tested since the annual report (May 1973). The conclusions reached are based on both these results and those reported in the annual report. The locations studied are the Climax and Henderson mines in Colorado and the San Manuel mine in Arizona. The rock types studied from each location are from: 1) Climax, medium-grained granite, fine-grained granite, granite porphyry, schist, and gneiss; 2) Henderson, rhyolite porphyry; 3) San Manuel, quartz monzonite and quartz monzonite porphyry. A description of the rocks was made including: color, texture, mineralogy, composition and fabric of fracture fillings, density, apparent porosity, and optical diffraction patterns. Unconfined and triaxial compression tests were run on the Climax and San Manuel specimens. Sonic velocities were measured during the compression tests; Shore sceleroscope hardness was measured before the compression tests. Conclusions are that some relation appears to exist between compressive strength and the following properties and features for all specimens: dynamic Young's modulus, sonic velocity, density, rock composition, slope of velocity curve, composition and fabric of fracture fillings-veinlets, and apparent porosity. There appears to be some relation between compressive strength and Shore scelerscope hardness for the quartz monzonite (San Manuel). A relation appears to exist between texture and compressive strength and the extent of failure on fracture fillings for schists, gneiss, and fine-grained granite (Climax). The amount of swelling clays (montmorillonite, hydromicas, etc.) present in the rock and the relative number of fractures in which they constitute of major portion of the fracture fillings are related to the strength of the rocks. Possible tests for checking the amount of these clays present is presented including saturation, dyes, and X-rays. A useful index relating to rock strength, as revealed in this study, is the presence of swelling clays in detectable abundances. These clays can be detected in the field with a simple wetting and striking test; in the laboratory they can be detected by X-ray and dye methods.

Jan 1, 1974

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

The principal activities of the Bureau of Mines Explosives Research Center (now Safety Research Center) during fiscal year 1968 (July 1, 1967, to June 30, 1968) are reviewed in part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in other media. Part 3 describes a short study on the thermal decomposition of RDX and HMX not destined for publication elsewhere. ACKNOWLEDGMENTS The Bureau gratefully acknowledges the support received through cooperative agreement in fiscal year 1968 from The Manufacturing Chemists Association.

Jan 1, 1970

By N. S. Petersen

As part of the Demand Evaluation Program of the Bureau of Mines to determine future needs for minerals, a study was instituted to develop and describe a methodology for approaching the problem of substitution between mineral commodities and between mineral commodities and other materials. The report comprises three sections: A review of general factors relative to substitution, a case study of the effect of substitution on zinc die-casting markets in recent years, and a general methodology for reviewing materials substitution with specific emphasis derived from reviewing substitution in the domestic zinc die-casting markets.

Jan 1, 1971

REFERENCES AND FOOTNOTES 1. U.S. Department of the Interior, Office of Surface Mining. Surface Coal Mining Reclamation: 10 Years of Progress: 1977-1987. Washington, D.C. August 3, 1987.48 pp. (For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington D.C. 20402.) 2. The Rural Abandoned Mine Program (RAMP), authorized by Section 406 of SMCRA, provides for the control and prevention o f erosion and sediment damages from unreclaimed abandoned mine lands. 3. The Small Operator Assistance Program (SOAP), authorized by Section 401(b)(1) and 507(c) of SMCRA authorizes up to 10 percent of the fees collected for the Abandoned Mine Reclamation Fund to be used for technical assistance to help qualified small mine operators obtain techincal data needed for permit applications. Operators who produce fewer than 300,000 tons of coal per year are eligible for assistance. 4. OSM regulations 30 CFR 816.42 and 817.42 require water from areas distrubed by mining activities be in compliance with all applicable state and federal water-quality laws and effluent limitations for coal mining established by the U.S. Environmental Protection Agency. 5. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 6. Sourse: Abandoned Mine Lands Fee Collection System, Data from OSM-1 form. 7. Source: OSM Field Office Annual Reports. 8. Johnson, W. and G.C. Miller, Abandoned Coal-Mine Lands: nature, extent, and cost of reclamation. U. S. Bureau of Mines, 1979,29 pp. PHOTOGRAPHIC CREDITS Front cover, pp. i, 1, 2 bottom, 7 right, 10 bottom left, l 1 top, l l bottom right, 12 top, 13 bottom, 14 bottom right, 15,16 bottom, 17 top, 17 bottom right, 18 bottom, 19, 20 bottom, 21 top, 22, 23, 24 bottom, 25 bottom, 26 bottom left, 26 bottom right, 27, 28, 29 top, 30 bottom, 32 bottom right, 33 top, 34 top, 35 top left, 35 bottom left, 35 bottom right, 36 top, 37, top right, 37 bottom, 38 bottom, 39, 41, 42 top, 43 bottom, 44 bottom left, 44 bottom right, 45, 46, 47, and 53: Chuck Meyers, OSM. Page 2 top and center: Tony Fuhs. Page 3: John Sharkowicz, OSM. Page 6 left: North American Coal Corp. Pages 6 right, 7 left, l l bottom left, 13 top left, 13 top right, 17 bottom left, 21 bottom, 25 top left, 25 top right, 29 bottom, 30 center, 32 top, 32 bottom left, and 38 top: Bob Welch, OSM. Page 10 top left: Donald Stump, OSM. Pages 10 right, 14 top right, 14 center right, 18 top, and 44 top: Ron Hill, EPA. Page 12 bottom: Texas Utilities Co. Pages 16 top, 20 top, 24 top: Tennessee Valley Authority. Page 26 top right and 26 center left: Richard Dick, U.S. Bureau of Mines. Pages 30 top, 33 bottom left, 33 bottom right, 35 top right, 36 bottom, 37 top left, 40 top, 40 bottom, 42 bottom, 43 top left, and 43 top right: Jim Boyer, OSM. Page 31 top left, and 31 top right: Bruce Wage, Western Energy Co. Page 31 bottom: Rex Wilson, OSM. Page 34 bottom: West Virginia Division of Abandoned Mine Lands. Page 35 center: William Weist, Jr., OSM.

Jan 1, 1992

By George A. Morgan

Output of mineral products was estimated to be unchanged in 1983 from that of 1982 with the exception of petroleum. The country began production of crude oil from the Seme Oilfield, and all output was exported. Wd and charcoal constituted 72% of Benin's total energy consumption, and imported petroleum products and electric power accounted for the remainder. Cement was produced from imported clinker. The gross domestic product (GDP) was $1,061 million in 1982, the latest year for which information was available.2 COMMODITY REVIEW Gold.-Exploration was underway at Perma by the U.S.S.R. as part of the United Nations development program. Gold had been produced previously at Perma, where a grade of 0.289 troy ounce of gold per ton was reported, An exploitation program for the deposit was to employ about 100 people, and output was targeted to reach 1,600 troy ounces per year. Recoverable reserves were put at 96,000 troy ounces.

Jan 1, 1985

By Rustu S. Kalyoncu

Nonoxide ceramics with improved high-temperature properties could substitute for high-temperature alloys and reduce toe Nation's dependence on imports of Cr, Co, Ni, and Mn. To meet this objective, the Bureau of Mines conducted research to synthesize u1trafine reactive boron nitride (BN) powders BN powders were prepared at temperatures ranging from -75? to 750? C. Low-temperature reactions (-75? to 200? C) between boron halides and N compounds led to formation of e1emento-organic compounds that were thermally decomposed to u1trafine (approximately 100-to 150-A particle size) reactive BN powders. BN powders were also prepared through the reaction of a 10w-me1tinginorganic B compound (boric acid, borax) with an organic N compound (carbimide and thiocarbimide) in N2 and/or ammonia (NH3) atmospheres at temperatures between 500? and 750? C.

Jan 1, 1986

By M. M. Fine

Research on the solid-fuel reduction of Knob Lake iron or was conducted to upgrade lean and high-grade ores and recover metallized products suitable for ironmaking or steelmaking. The program included bench-scale tests plus a number of continuous campaigns in a 34-inch by 36-foot rotary kiln. In the laboratory, metallizations in excess of 90 percent were achieved by reduction of crushed ore with lignite at 950° C. Subsequent grinding (to minus 200 mesh) and wet magnetic separation yielded concentrates analyzing less than 3.0 percent SiO2 and more than 90 percent Fe. Virtually complete recovery of the iron occurred. During early continuous tests the crushed ore created a serious ringing in the kiln which was solved by balling the fines with bentonite. Unfortunately, at this temperature (950° C) the bentonite militates against the concentratability of the metallized product. For example, a run on direct-shipping ore produced concentrates of 89.5 percent Fe and 4.5 percent SiO2. At 500° C the adverse effect of bentonite disappeared and concentrates of 88.4 Fe and only 2.5 percent SiO2 resulted. However, with comparable feed r Los, the metallization dropped to 73 percent.

Jan 1, 1969

By G. T. Fisher

The material requirements of carbide cutting tools for machining steel and cast iron are dependent on WC bonded with Co, with additions of TaCand TiC. The Bureau of Mines is conducting research to devise substi-tute materials, based on Ni-alloy-bonded TiC, for C-5-grade cutting tool applications. This substitution would result in less dependence on foreign sources for Co, Ta, and W, and use of lower cost materials. In this preliminary study, the Bureau investigated the effects of composition and processing variables on the transverse rupture strength and hardness of Ni-alloy-bonded TiC to identify compositions that exhibit promising mechanical properties. Further systematic modification of these compositions by soild-solution strengthening additions would subsequently be evaluated to obtain cutting tool materials with requisite properties and performance for C-5 applications. Compositions for evaluation were prepared by a powder metallurgy method of cold-pressing and liquid-phase sintering. Complementary analysis of compositions included chemical analysis, X-ray diffraction, energy-dispersive X-ray spectro-scopy, and density measurements. Based on results of this investigation, promising compositions were determined to be 59.37TiC-25Ni-5Mo-lO.63Mo2C, 59.68TiC-25Ni-3.33Mo-1.77Mo2C-6.67W-3.55WC, and 59.35TiC-25Ni-l.67Mo-3.54Mo2C-3.33W-7.1WC.

Jan 1, 1987

By Theodore L. Turner

This Bureau of Mines report describes calcination of kaolinitic clay in a direct-fired 2-1/2- by 24-ft rotary kiln at 750° and 775° C. Methods for preparing kaolin feed materials and characterization of calcined products are discussed. Approximately 99 pct of the alumina in a typical eastern Georgia kaolin was soluble in HC1 after calcination at either 750° or 775° C.

Jan 1, 1982

These tentative inspection standards have been prepared as a guide for the Federal inspection of the anthracite mines of the United States. The Federal Coal Mine Inspection Division is not a mining-law-enforcement

Jan 1, 1943

By Clarence A. Wright, JAMES T. NORTON, JAMES G. PARMELEE

The object of this paper is to give to mining companies and to all others who are interested some idea of the possibilities in the treatment, by differential flotation, of lead-zinc ores of the Coeur d'Alene region and other districts. The purpose of these investiga.. tions is not to evolve a differential flotation process that would replace present methods of gravity concentration but rather one that could be applied to the relatively fine material and slime produced in the mills and treated unsuc_pessfully by gravity methods or by flotation. It is expected, of course, that the products to be obtained by differential flotation would be of much better grade than those now produced by flotation in the Coeur d'Alene mills. In view of the fact that it has been difficult to obtain representative samples of flotation feed from the mills, owing to the necessity of shipping the material wet and free from oil or other foreign matter that might be deleterious to the differential separation of the sulphides, the writers have felt justified in running flotation tests with the mill feeds in order to ascertain whether a differential separation of the sulphides could be effected. However, two different lots of flotation feed were tested for differential flotation, and the results of tests of one of these are given in this report. It is hoped that it will be possible later to test out the flotation feed for differential flotation on a large scale in some of the mills. This paper covers part of the investigations carried on by the United States Bureau of Mines in cooperation with the Idaho Bureau of Mines, the University of Idaho, and certain mining companies of the Coeur d'Alene region. Although the results of the tests included in this report are not to be considered final, they indicate possibilities and may suggest others leading to a solution of the problem of separating lead and zinc sulphides by differential flotation in the treatment of certain ores.

Jan 1, 1921

By E. J. Gleim

A list of permissible mine equipment, tested and approved by the Bureau of Mines previous to January 1, 1942, was published in Bureau of Mines Information Circular 7207.3/ The list of that date was complete as to equipment then available and in current use. Information Circular 7240,4/ published as a supplement thereto, listed equipment approved curing the calendar year 1943. The present list is another supplement covering approvals issued during the calendar year 1943. The items are numbered to indicate the consecutive order in which each type of machine or device was approved in its particular classification. Thus, Information Circular 7207 gave 19 drills and drilling machines on the Bureau's active list. No additional approvals were given in 1942, but the three issued in 1943 bring the total to 22. Item 102, under Loading Machines and Conveyors, also appeared in Information Circular 7207, and items 120 and 124 appeared in Information Circular 7240. These numbers are repeated here to show that approvals were granted during 1943 for additional voltages on machines previously listed for one voltage only. Equipment listed in these circulars is approved by the Bureau of Mines only when found upon inspection and test to comply with minimum standards of safety as outlined in schedules prepared on the basis of many years of experience in dealing with safety problems of the coal-mining industry. The use of such equipment in mines known to be gassy, as well as in those that may become so, is earnestly recommended in the interests of safety. This circular is published so that the industry may be kept

Jan 1, 1944

By Doris M. Hyde

Mineral output and trade in the Central American countries were directly or indirectly affected by the sometimes violent civil unrest and recessionary economic developments that have pervaded the region for several years. Central American countries found their foreign exchange export earnings and traditional market areas shrinking while essential import costs were rising. Restricted spending measures were adopted by governments and private industries. Domestic investment funds for mineral development and exploration projects were among the first casualties of these austere budgetary measures, especially since weak demand and depressed mineral prices diminished the probability of a favorable cost-benefit ratio. The lack of physical security and political stability also discouraged private foreign investment. The United States Congress enacted the Caribbean Basin Economic Recovery Act of 1983 (19 U.S.C. 2702), more popularly known as the Caribbean Basin Initiative (CBI). This legislation was designed to stimulate economic recovery and promote economic development by increasing private investment and trade in the Caribbean Basin countries. The act provided for the elimination of U.S. duties on most trade items imported directly from eligible Caribbean countries, provided at least 35% of the product value originated in the region. The financial assistance components of the CBI were to be supportive of the basin's private sector as well as assist general economic stabilization programs.

Jan 1, 1985