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By William H. Hamilton

This report describes the results and conclusions of the development and evaluation of a unique concept for a lightweight air powered drill tool for probe drilling in anthracite mines. A concept model of the lightweight air powered tool was constructed and evaluation testing conducted at the Kocher Coal Company Porter Tunnel Mine. The unique anchoring method proved to be extremely satisfactory and the overall light-weight air powered drill tool concept proved feasible. Based on the results of the concept model testing, two prototype production units were designed and manufactured. These prototype units proved to meet all of their design requirements of lightweight, portability, drilling controllability, structural integrity and miner acceptance. The need for a better bit and drill steel system, however, became evident during the testing program and recommendations are made for further investigation and development of a bit and drill steel system suitable for this application.

Jan 1, 1979

By L. W. Higley

Electrowinning metals from solutions leached from low-grade ores is becoming an increasingly important extraction method as the metal industry turns to pollution-free recovery processes. Lead-alloy anodes are used industrially in the electrolytic recovery of zinc and copper. However, associated with the use of these anodes are the inherent problems of stability and lead contamination of the cathode. In an effort to eliminate these problems, the Bureau of Mines has developed a relatively inexpensive lead dioxide anode for electrowinning metals from strong acid solutions. The anode was prepared by depositing Pb02 directly on a titanium blank in a strong HN03-Pb(N03)2 solution at 2.15 to 6.45 A/dm2 and 60° C. This anode was tested in zinc and copper electrowinning cells containing 200 gpl H2S04 and 35 to 100 gpl metal ions at the current density of 3.23 to 6.45 A/dm2. Contamination of the cathode by lead was =0.005 pet. A 30-day test at 6.45 to 12.90 A/dm2 in an electrolyte containing 200 gpl H2S04 and no metal ions resulted in a slight change in surface morphology of the Pb02 anode but no measurable change in anode weight or dimensions.

Jan 1, 1976

By Paul M. Price

The Mouat mine, Nye, Mont., was reopened in 1953 by the American Chrome Co. under a Defense Minerals Production Administration contract. Operations were terminated in 1961 after completion of the contract. Mining methods employed during this period are described in detail, and cost data are presented by years for 1953 through 1959. Ultramafic rocks of the Stillwater complex in Montana contain the largest domestic resource of chromite, and the Mouat mine has been the largest producer. Mine reserves were estimated in 1960 to be about 4.4 million tons containing 22.5 percent Cr2O3. The chromite deposits occur as a series of overlapping bands or lenses roughly paralleling the steeply dipping layers of the complex. Only two of the chromite layers have proven to be of economic importance. One layer is 2 to 16 feet wide; the other is 3 to 8 feet wide. Shrinkage stoping was generally used throughout the mine, but various methods of ore breaking, stope drawing, chute construction, etc., were tested to improve output and lower costs. Long-hole stoping proved to have limited use. Breasting down benches, developed outward from the center of the stope with air-leg drills, was satisfactory only in wider stopes. At the close of operations, the company had standardized the use of lightweight stopers to advance a flat back by breaking from a centrally located face. Mining costs were reduced 47 percent during 7 years of operation.

Jan 1, 1963

By John D. Spencer

Surveys to establish the quantity and quality of coals available for metallurgical, industrial, and energy use, investigations to develop better mining methods, and studies aimed at improving the health and safety of those who mine the coal highlighted Bureau of Mines research and technologic work on coal in 1968. Also being developed are more efficient methods of coal preparation, transportation, storage, and utilization. Supplementing this effort are projects designed to assure minimum disturbance of land, water, and air resources. Research centers and laboratories of the Bureau of Mines are listed in appendix A. Publications released during 1968 are cited with the various projects and in appendix C. Organizations that cooperated in the work in various ways are cited in appendix B.

Jan 1, 1969

By John A. Johnson

For the purpose of comparing the amounts of dust produced by various mining operations, samples of atmospheric dust were collected during a complete cycle of drilling, blasting and mucking at or near the face of the Bureau's Mount Weather testing adit while the efficiency of several types of stemming in metal-mine blasting was being investigated. ACKNOWLEDGMENTS All gas samples were analyzed in the laboratory of the Bureau of Mines Gas Section at Pittsburgh, Pa.

Jan 1, 1939

By Keith D. Rosbury

The basic objective of this project was to determine the cost-effectiveness of dust control used on unpaved mine haul roads. Field testing was conducted at three surface coal mines (two in Wyoming, one in southern Illinois) for a total of 20 weeks. The highest control efficiency measured for a chemical dust suppressant, 82 percent, was for calcium chloride two weeks after application. Generally, however, the control efficiencies hovered in the 40 to 60 percent range over the first two weeks since application, and then decreased with time. After the fifth week, the limited number of data points suggest a control efficiency of less than 20 percent. Composite watering data were fairly uniform. Watering once per hour resulted in a TSP control efficiency of approximately 40 percent. Doubling that application rate increased the control effectiveness by about 15 percent to 55 percent. Chemical dust suppressants (primarily salts and lignons) can be shown to be more cost-effective than watering under some conditions. Data summaries and the analysis of data are contained in Volume I. Volume II contains basic data.

Jan 1, 1983

By P. R. Jones

A computer program was written for design and cost of a shell and tube heat exchanger in which the total cost, which includes annual fixed charges and annual operating costs, was minimized. The program was written for the type of heat exchanger in which only the tube side pumping costs were significant and for triangular pitch, single or multiple pass, heating or cooling, and no change in phase. Tube diameter was not optimized since the tube dimensions do not affect the cost very much. However, the tube dimensions do affect the shell diameter, number of tubes, and length of tubes; and price optimum design was obtained for four standard tube diameters. Standard heat exchangers having at least the required area are also listed. The program was made adaptable to various fluids and to various tube dimensions by including many of the required data such as physical properties of the fluids, tube data, and standard shell data as input data.

Jan 1, 1969

By R. W. Watson

A belt-wearable self-contained self-rescuer (SCSR) manufactured by the CSE Corp. and designated the "SR-1OO" was evaluated for safety in the underground mine environment by the U.S. Bureau of Mines. The evaluation consisted of laboratory tests on the chemicals contained in the unit and field trials to simulate the mine environment. This report summarizes the test results and compares the results with those from earlier tests with chemical and compressed oxygen self-rescuers. It was concluded that the new SCSR did not pose any different or more severe hazards than the earlier units. In view of the mine-proven safety record of the SCSR's now in service, no reason could be found to disallow use of the belt-wearable unit.

Jan 1, 1991

An underground mine disaster is an accident of major proportions that takes a significant toll in human lives. A disaster usually disrupts the normal functioning of a mine and may result in entrapment of miners whose normal egress from the mine is cut off. A disaster often necessitates a rescue operation and a means of keeping the trapped miners alive while they await rescue. Explosion, fire, inundation of water or toxic gases, and collapse of a major portion of a mine are among the causes of mine disasters. Miners threatened by such an occurence must either bring the situation under control (e.g., by extinguishing a fire) or remove themselves from the danger. If control is unsuccessful, they must retreat to a place of safety. Four different activities may be involved: evacuation, escape, survival, and rescue. Evacuation is the orderly exit of people from the mine using previously identified escapeways and following a previously determined evacuation plan. Miners whose normal evacuation routes are blocked may be able to find alternative exit routes and escape by their own efforts. For those who cannot, the issue becomes survival while waiting to be rescued. The survival period may last for many days while rescue efforts are mounted from outside the mine.

Jan 1, 1981

By Joseph A. Vanous

The inductive communication system was developed under this contract for use in the hoist of deep mines. This program was a four phase program with experimental dual frequency equipment resulting from Phase I, emergency single frequency equipment developed under Phase II, and equipment documentation required under Phase III. An additional emergency system was provided under Phase IV.

Jan 1, 1976

By Ned Baker

Details are given of a fuel-induction system for a hydrogen, fueled engine. The induction system was designed to preclude backfire otherwise common in hydrogen fueled engines. System features and test data are presented and discussed in the context of the requirements peculiar to use in an underground mine environment. The fuel induction-system when tested in conjunction with a modified Caterpillar 3304 engine provided backfire free engine operation and satisfactory engine performance.

Jan 1, 1982

This appendix contains the list of equipment selected for the capitol cost estimate, with the respective quotations from their vendors/manufacturers. A vendor response report along with a separate equipment and motor list has been included in the first part of this appendix.

Jan 1, 1979

By V. B. Dale

San Manuel has been a modern prodigy from its inception to its present status as a block-caving operation producing 33,000 tons per day. The deposit was discovered, prospected, and developed with modern techniques, and nearly all planning was done from results of an extensive drilling program through an average overburden of 670 feet. The Federal Government had a prominent part in the discovery and primary development of San Manuel. The first 17 holes were drilled by the Bureau of Mines, and discovery of the large, low-grade, disseminated copper deposit is credited to the Bureau. A loan fund of 94 million was granted through the Reconstruction Finance Corporation to the San Manuel Copper Corp. for development of the deposit and erection of concentrating and smelting facilities. Then, while the mine was still being developed, the Defense Materials Procurement Agency contracted to buy a large amount of copper at a pegged price.

Jan 1, 1962

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used for making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By Mark I. Copeland

This study was conducted by the Bureau of Mines to determine the effect of steel reheating practices in burning natural gas on the amount of silicon required to prevent the formation of copper on steels containing up to 1 wt-pct Cu. Formation of copper, which causes surface hot shortness, was readily prevented by as little as 0.3 wt-pct Si and by 2 vol-pct excess oxygen in the furnace atmosphere when reheating steels containing up to 0.8 wt-pct Cu. Up to 0.8 wt-pct Si content and careful control of reheating conditions were necessary for steels containing 1 wt-pct Cu. Best conditions for these steels were reheating to 2,200° F (1,205° C) in burning gases containing 2 vol-pct excess oxygen, and then to higher temperatures in gases of 6 vol-pct excess oxygen. Slag and mold wash were not detrimental on steels reheated for 8 hr by a soaking-pit-type furnace schedule, but they were problematical on steels heated for 2 hr by a pusher-type furnace schedule. The effect of silicon contents on scaling rates also was determined.

Jan 1, 1974

By A. George Stern

[In the examination of bentonitic clay suspensions used for oil-well drilling fluids3/ (and for other purposes, such as a core binder for foundry sand) it is important to have comparative tests for evaluating them. A satisfactory clay for these and other purposes should have the property of forming what is commonly called a "gel," but the measurement of this property has been a real problem. To date the solution has not been satisfactory, and some of the difficulties are considered in, this, paper, which describes a simple form of instrument (identified as an eykometer) for measuring the yield point under hydrostatic conditions of non-Newtonian clay suspensions, including those muds that are thixotropic. An oil-well drilling mud serves several functions, many of which depend on the "gel" characteristics of the mud. Among the more important functions are: (a) To plaster the sides of the hole to prevent caving of the walls; (b) to prevent the loss of the circulating fluid out of the hole by seepage; (c) to carry sand and cuttings out of the hole to the surface as they are formed by the rotary drill; and (d) when circulation of the fluid stops for shut-down or other unavoidable cause, to hold the cuttings in suspension by the setting up of the gel, thereby avoiding the difficulties that result when these cuttings are allowed to fall through the fluid and pack at the bottom of the hole.]

Jan 1, 1940

By Ruth F. Brinkley

This circular describes the activities and publications of the Bureau of Mines, Explosives Research Laboratory4 for the fiscal year 1960 (July 1, 1959 -June 30, 1960). Part 1 describes briefly the principal projects that were active during the report period, and presents some data not scheduled for publication elsewhere in the near future. Certain of the results are only preliminary and should be regarded as tentative, pending the findings of the completed investigation. Publications that appeared during the report period are listed and described briefly in part 2. In general, the research activities reported in these publications antedate fiscal year 1960. The published material relating to activities that are still current is indicated by references in part 1.

Jan 1, 1962

By Rose L. Ballard

This chapter summarizes data on crude nonfuel mineral production for the United States, its island possessions, and the Commonwealth of Puerto Rico. Included also are the tables that show the principal nonfuel mineral commodities exported from and imported into the United States and that compare world and U.S. mineral production. The detailed data from which these tables were derived are contained in the individual commodity chapters of volume I and in the State chapters of volume II of this edition of the Minerals Yearbook. Although crude mineral production may be measured at any of several stages of extraction and processing, the stage of measurement used in this chapter is what is ordinarily termed "mine output." It usually refers to minerals or ores in the form in which they are first extracted from the ground, but customarily includes the output from auxiliary processing at or near the mines.

Jan 1, 1983

By D. E. Pollock, J. A. Organiscak

Water sprays and water powered scrubbers have both been utilized in the mining and milling industry to suppress airborne dust. Unconfined water sprays operated at lower water pressures of ?689 kPa (?100 psig) can be very effective at wetting the mine product at the dust source and significantly reducing the amount of respirable dust that becomes airborne. However, unconfined waters sprays can be somewhat ineffective in actually removing airborne dust from the air. On the other hand, water powered scrubbers operating at higher water pressures of ?1,724 kPa (?250 psig) in physical enclosures or ducts have previously been demonstrated to be very effective in removing airborne dust from the air. These higher operating water pressures are uncommon in many mines and mills, so their use is limited. The National Institute for Occupational Safety and Health (NIOSH) recently investigated the performance of a lower-pressure, water powered inline series spray scrubber for removing localized airborne dust emitted at the source. Results showed noticeable improvements in airborne dust capture efficiency through the operation o f multiple inline series hollow cone spray nozzles within a round duct or pipe at the same water pressure as a single spray. Operating hollow cone spray(s) at higher water pressures noticeably improved airflow through the scrubber and yielded some additional scrubber efficiency improvements. Thus, in-line spray scrubber efficiency trade-offs were observed to be made by altering spray power components of water pressure and/or quantity (number of sprays). Results show that, on average, up to 0.23 and 0.32 m3/s (484 and 679 cu ft per min) of airflow at 0.81 and 0.69 dust capture efficiencies can be achieved with three 81° and 33°hollow cone inline series sprays, respectively, operating at 1,655 kPa (240 psig).

The low production rates associated with the underground metal mining industry have received considerable attention during the last decade. A number of significant technological advancements, in the form of new equipment, have taken place to improve the economics of ore production. Unfortunately, an extremely important factor in the equation -- the operator protection and safety -- continues to receive a low priority. The underground metal mining industry has one of the poorest industrial safety records in the United States. Equipment operators are constantly being placed in hazardous situations. Even one fatality is one too many. All of us bear the responsibility to eliminate it. This project is one of the important steps currently being undertaken by the U.S. Bureau of Mines to improve the operational safety of seven major pieces of ore handling equipment commonly used in underground metal and non-metal mines. The objectives of this study are; (a) to identify the existing hazards associated with the operation of the specific equipment, and (b) to recommend practical solutions that will minimize these hazards and reduce operator injuries. These recommendations are to be in the areas of equipment design improvements, additional operator protection and warning devices, equipment operating procedures and any modifications to the existing safety regulations.

Jan 1, 1975