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By R. T. C. Rasmussen

"INTRODUCTION The primary purpose of the Bureau of Mines electrolytic manganese pilot plant at Boulder City, Nev., is to improve the Bureau-invented electrowinning process and to determine the applicability of the process to the extensive domestic low-grade manganese ores with a view to making the United States dependent upon foreign sources of manganese. 3/4/ Incidental to accomplishing this purpose, the pilot plant has produced a substantive quantity of electrorytic manganese since the start of operations late in 1941; present cabacity about 1 ton a day of manganese metal. A second important purpose of the pilot plant is the supplying of electrolytic manganese for full-scale tests in cooperation with industrial users of manganese.The Rustless Iron& Steel Corp., Baltimore, Md., was the first steel company to cooperate with the Bureau of Mines in large-scale testing of electrolytic manganese. Arrangements were made with C. E. Tuttle, then president of the corporation, whereby the Bureau would supply electrolytic manganese to make a sufficient number of full-scale stainless-steel heats to demonstrate thoroughly its merits as a replacement for low-carbon ferro-manganese in the corporation's stainless-steel practice. The corporation's purpose in the investigation was to determine the possible advantages of electrolytic manganese resulting from its almost complete lack of phosphorus and caroon that might offset its then considerably higher cost per unit of manganese than low-carbon ferromanganese. The data presented herein are based upon reports of A. L. Field, technical director, and L. Weitzenkern, research engineer of Rustless Iron & Steel Corp.; they are supplemented by observation of the author who visited the plant during the tests."

Oct 1, 1945

By Sean Gallagher, Gene Wilson, Christopher Mark, Craig S. Compton, Gregory M. Molinda

Falls of small pieces of rock from between roof bolts continue to cause fatalities and to injure hundreds of coal miners each year. Roof screen is the most effective way to prevent these incidents, but some mines are reluctant to use it because they believe installing screen can be awkward, expensive and time-consuming. The most common type of roof bolting machine used in mines today is the dual boom, outside-controlled roof bolter. Mines who install roof screen using these machines have developed some machine modifications and techniques to ease roof screen installation. This paper describes some successful techniques and machine modifications that are being used in productive mines to assist with roof screen installation. Since the material handling involved with roof screen installation can expose miners to an increased risk of musculoskeletal injuries, the National Institute for Occupational Safety and Health (NIOSH) ergonomists, designed machine modifications and implemented a series of tests to evaluate roof screen handling procedures for outside-controlled, dual boom roof bolting machines. Roof screen installation can also have a positive economic impact on a mine by reducing the cost of injuries, workers’ compensation, required spot or re-bolting, and clean-up of long term travel and belt entries.

By Kim B. Shedd

The U.S. Bureau of Mines Particulate Mineralogy Unit examined the habits of six zeolite minerals commonly occurring in domestic zeolite deposits. Mineral habit is of interest because current theory on the potential for sarcoma production in test animals emphasizes the size and shape of mineral particles, without regard to composition or structure. A scanning electron microscopic study revealed that, of these six minerals, only mordenite and erionite crystallized in acicular to fibrous habits, The fibrous varieties of these two minerals were characterized by size and shape on the transmission electron microscope, and their dimensions were compared with those of asbestos and amphibole cleavage fragments. When comminuted, these two minerals possess "fibrosity indices" similar to those of amphibole cleavage fragments. One sample, a rare woolly erionite, has uniform widths, large aspect ratios, and a "fibrosity index" similar to those of asbestos.

Jan 1, 1982

By P. M. Ambrose, C. Travis Anderson, Cresap Moss, R. S. Dean

"MANGANESE METALMethods of PreparationMethods of preparing the manganese metal that has been used in chemical and metallurgical investigations have passed through a cycle. Most of the investigations made before the turn of the century used Moissan's pyrophoric manganese. 5/ This material was made by electrolysis into a mercury cathode and distillation in vacuo. It was essentially a pure material, and investigations in which it was employed (with proper precautions against oxida¬tion) led to accurate results concerning the intrinsic behavior of metallic manganese.An early investigation of the properties of ""Manganese-by-Mercury"" was made by M. Guntz. 6/ He prepared manganese by electrolysis of a concentrated MnCl2 solution with a mercury cathode. The manganese amalgam was pressed through chamois and distilled in vacuo (2 to 3 cm. of mercury) at 200°0., slowly rising to 250°0. Guntz recognized especially the decreased reactivity of manganese with increased temperature of mercury distillation. The most careful and com¬prehensive study of manganese made by this method is that of Kuh 7/ whose work unfortunately was never published in an accessible journal.Royce and Kahlenberg 8/ studied the electrode potential of manganese made by this method."

Nov 1, 1939

By Matthew N. Rubin

This report summarizes the work performed under USBM Contract No. H0155155. The purpose of this work was to obtain operational data on retrofit noise control treatments suitable for use in coal preparation plants. This data was obtained by evaluating the performance of four categories of noise control treatments which were installed in a commercial coal preparation plant. The four categories of treatments were resilient screen decks, resilient impact pads, chute liners, and curtains. The selection, installation and initial evaluation of the treatments was documented in the Volume I report issued in 1977. This Volume II report summarizes the results of the long-term evaluation of the original treatments, as well as some additional tests which were conducted on elastomer-clad (resilient) screen decks. This project demonstrated the feasibility of a number of retrofit noise control treatments, some of which also proved to be quite durable over the long term.

Jan 1, 1982

By R. S. Dean

In general, the Division conducts investigations relating to the treatment of ores and metallurgical products from the condition to which they are mined to the refined metal. At the object of conserving natural resources and eliminating waste by furnishing information on current methods of metallurgical practice making fig fundamental studies of metallurgical processes and developing new processes and alloys to the point of demonstrating their or value. Office of the Chief Engineer The functions of the technical units of the Office of the Chief Engineer are indicates

Jan 1, 1941

By G. W. Jones

In a previous report'/ results were given and a method outlined whereby from a knowledge of the composition of the natural gas and of the inflammability limits of the individual constituents composing the natural gas, the limits of inflammability of natural gas and air mixtures could be closely calculated. This method is based on the application of Le Chatelier's law as modified by Coward, Carpenter and Payman,5/ to apply to a mixture of any number of combustible gases. This law must not be used indiscriminately, because many exceptions have been found. For example, when ethylene, acetylene, hydrogen sulphide, or chlorinated hydrocarbons are present the law may not hold. For a discussion of the many exceptions which have been found, reference should be made to a report by Coward and Jones.6/

Jan 1, 1933

By I. Liebman

The Bureau of Mines conducted experiments on coal dust explosion suppression. The investigation took place on a beltway in the double-entry of the Bureau's Experimental Mine. Using conditions that simulate those in a working mine, the investigation showed that a coal dust explosion can be readily initiated in a conveyor belt entry. Also, the explosion can spread into adjacent entries through opened crosscuts (stopping destroyed by explosion) to propagate for long distances even though the adjacent entries are rock dusted in compliance with regulations. Passive water barriers (water-filled tubs) were found to be effective in suppressing explosions on a beltway; however, barrier efficiency was reduced by opened crosscuts. The study indicated that the beltway barrier should be the distributed type consisting of continuous rows of water-filled tubs covering long distances along the entry. A plan is outlined for the installation of a water barrier system in a working coal mine for the protection of a beltway.

Jan 1, 1981

By Diane M. Doyle-Coombs

In late July 1985, air samples from a sealed portion of the Quinland coal mine in West Virginia showed the presence of carbon monoxide (CO). Mine Safety and Health Administration (MSHA) personnel concluded that a fire was burning behind the seals. Since an imminent danger existed, the mine operator was given a closure order. The gases behind the seals were monitored and almost 2 million ff of carbon dioxide (C02) gas was pumped into the sealed area to stabilize the environment. Sixteen days after the closure order was issued, MSHA allowed the mine to return to production. Approximately 1 yr later, mine management submitted a seal breaching request to MSHA in order to drive a set of entries to further develop the mine. The Bureau of Mines established a sampling strategy and monitored gases from behind the sealed area during the breaching operation until the atmosphere was safe. This report is an account of the seal breaching conducted by the mine, MSHA, and the Bureau. The logistics of this event, the sampling strategy, and the equations applied could be used by the mining industry in future breachings or mine recovery operations. Time to reenter the area was calculated by using the methane (CH4) concentrations sampled at the discharge of the seals. Tracer gas was used to verify the ventilation flows through the area.

Jan 1, 1988

By John J. Sammarco

The U.S. Bureau of Mines seeks to increase safety and efficiency in U.S. coal mines. One approach is to develop technology for automation of a continuous mining machine. Realization of an autonomous mining machine requires development of subsystems for machine intelligence, navigation-positioning, and computer control. This report focuses on investigation of one subsystem, an onboard heading system, which would be responsible for determining and controlling machine heading. The onboard heading system investigated is a multisensor system to determine machine heading, pitch, and roll. A directional gyroscope provides heading (yaw), fluxgate sensors provide a compass heading, and gravity-referenced clinometers give machine pitch and roll. The system utilizes a dedicated microcontroller networked to an external system of computers. Tram commands, supplied to the network from external computers, are executed by the onboard system. Sensor feedback is employed for closed-loop control of machine heading by controlling pivots and turns. The report discusses operating limitations and error sources of system sensors and presents test results of closed-loop control of machine heading. Results of tests with a mining machine are used to exhibit various sensor shortcomings and to evaluate control of pivots and turns.

Jan 1, 1990

By E. E. Ungar

Criteria applicable to noise in coal cleaning plants are presented, and the generally applicable noise control principles and approaches are discussed. The operating characteristics and equipment of coal cleaning plants are described. Considerations entering in the selection and design of noise control means are delineated, and specific means for equipment noise reduction are described. The limited utility of acoustically absorptive materials in plant spaces is indicated, administrative means for reducing worker noise exposure are pointed out, and ear-protective devices are described briefly. The reduction of plant noise reaching nearby communities is discussed. Programs leading to quieter machines an coal cleaning plants are suggested.

Jan 1, 1974

By J. L. Thompson

The U.S. Bureau of Mines conducted a water-jet-studies program using a single-bit, in-seam test unit to determine effects of a moderately high-pressure (up to 10,000 psi) water-jet-assisted cutting system on rock weakening. The in-seam test unit was used to obtain cutting force data in tangential, normal, and side force directions. Conical continuous miner and radial longwall miner bits were used to penetrate test samples of coalcrete, Berea sandstone, and Indiana limestone with unconfined compressive strengths of 4,600, 8,000 and 10,000 psi, respectively. Depth of cut in the coalcrete tests was 1 in, with 2-in cut spacing (2:1 ratio). Because of cutting equipment and instrumentation limitations, the Berea sandstone and Indiana lime-stone were cut using a 0.5-in depth of cut and 2-in spacing (4;1 ratio). Bit velocity was maintained at 25 ft/min for both bits. Each specimen and bit type was tested using 0.3-, 0.6-, 0.8-, and 1.0-mm-diam nozzles and water-jet pressures of 2,500, 5,000, 7,500, and 10,000 psig. Water-jet-assisted cutting decreased average resultant conical and radiallongwall bit cutting forces 6.4 and 8.4 pct in coalcrete, 5.5 and 1.4 pct in Berea sandstone, and 2.0 and 5.5 pct in Indiana limestone. Slight reductions of power requirements resulting from water-jet assist were ascertained during these experiments.

Jan 1, 1989

This Bureau of Mines publication contains the texts of the four papers presented at the May 6-7, 1980, seminar on the role of overburden analysis in surface mining. Coverage includes the geologic distribution of pyrite and calcareous material and its relationship to overburden sampling, overburden sampling and analysis, use of soil-overburden data in mine planning and development, and minesoil classification.

Jan 1, 1981

By Felix A. Vogel

Rutile concentrate, used in the manufacture of welding rode, smoke-screen chemicals, and alloys, is being produced by the Titanium Alloy Co. of Arkansas at its mine and. mill in Magnet Cove. The company estimates a substantial reserve of recoverable rutile. This is a new operation, and production figures are not known. Previous operations had stripped the placer material, leaving the underlying mineralized zone. INTRODUCTION This report describes the mining and milling; operations of the Titanium Alloy Co. of Arkansas. The property was examined by the author on March 4, 1942, and subsequent dates. J. A. Wood, general manager, was very helpful in supplying information.

Jan 1, 1944

By A. Monomakhoff

If a conductor traversed by an electric current is broken, a conduction forms in the air between the two broken ends of the wire. This conduction manifests itself in an initial phase by an electric spark and, in a second phase, by an arc if the the circuit continues to supply sufficient power. This arc goes out when the distance between the two ends of the conductor becomes sufficiently large. If the break occurs in an explosive atmosphere, the energy contributed by the arc can cause an explosion. To avoid such accidents, electric circuits that may be utilized in hazardous atmospheres can be made "intrinsically safe". The investigation which we conducted is part of a research project on the intrinsic safety of arcs of high intensity but short duration, in the case of resistive circuits. We developed an electronic system which makes it possible to limit the duration of an arc at the level of the break of a conductor traversed by a current with a possible maximum intensity of 80 amperes. This experimental device for monitoring and measuring the parameters of the arc has shown that arcs of high intensity but with a duration limited to a few microseconds do not ignite an explosive methane-air mixture.

Jan 1, 1975

By M. Didyk

The final objective of a mine ventilation project is to find a way of supplying the working faces with the necessary quantity of air to dilute all the possible air contaminants to safe limits and to maintain the temperature, humidity and oxygen content within desirable limits. To accomplish the aforesaid, decisions have to be made at early stages of planning and design of a mining operation. That is, ventilation and mine planning are closely related and interdependent, and experience has proved that improvisation as related to mine environment is rarely optimal in ventilation engineering. Mine management should be concerned with two general aspects of ventilation problems. The first is related to the statuatory requirements which are usually the minimum standards that have to be maintained. During the last two decades, mining laws have become increasingly stringent and management of operating mines had to face the effects of these externalities. In some cases these required either a production rate reduction or additional mine development. The second aspect that management should not overlook is the technical and economical importance of mine ventilation on the overall mining cost. In coal mining it is necessary to move, on an average, five tons of air through the mine for each ton of coal produced. The power cost incurred is perhaps the single most important direct cost assigned to ventilation but it is not the only one. Other costs that should be considered include the supervisory labor cost, fan depreciation and maintenance, doors, stoppings and regulators construction cost and maintenance, the additional mine airways development and maintenance because of ventilation requirements. That is,

Jan 1, 1977

By Thomas M. Barczak

The U.S. Bureau of Mines has been conducting research to optimize the design and utilization of mine roof support systems. An objective of these efforts is to evaluate the mechanical and structural responses of various mine roof support systems under simulated load conditions in the Bureau's mine roof simulator. Underground studies are also made to evaluate the in situ behavior of support structures. The purpose of this report is to document practical applications for longwall face and gate road supports that have resulted from these studies. This report is not intended to be an all-inclusive manual on every aspect of support utilization, but it does provide a comprehensive assessment of practical considerations relating to the mechanical and structural behavior of these support systems. Forty-six recommendations are made to provide assistance to mine operators in the testing, selection, and utilization of longwall face and gate road supports. Many of these recommendations offer innovative solutions to everyday problems faced by mining personnel in the control of ground in longwall mining.

Jan 1, 1989

By G. L. Fitzpatrick

Preliminary results of an experiment in seismic holography indicate that the techniques of acoustical holography may be successfully used with seismic waves to determine the size and general shape of underground objects. This experiment was carried out under field conditions on a moderately large scale compared with the typical laboratory experiments in acoustical holography. The object to be mapped was a 100-foot-diameter, spherical, low-velocity zone of explosively fractured rock in oil shale at an average depth of 80 feet. The seismic wavelength of the Fourier component wave used in making the seismic holograms was 50 feet at a frequency of 140 cps. The hologram sampling aperture was 226 feet square and was sampled by 441 geophones in a 21 by 21 rectangular array. One novel aspect of the experiment was the use of a wide-band polychromatic explosive source of seismic waves rather than a narrow-band quasi-monochromatic vibrator source. A successful laser reconstruction of the object image from a lensless Fourier-transform hologram in the form of a 5/l6-inch-square photographic transparency is illustrated. The size of the underground object measured from the laser reconstruction of the object and the size inferred from a knowledge of the amount of explosives used to fracture the site and the tensile strength of the oil shale are found to agree.

Jan 1, 1972

By Paul S. Goodman

Volume II The purpose of this study is to explain reasons for the productivity differences in mining crews. The literature on group productivity is examined. Then a new approach to estimating productivity differences is proposed and estimated across seven different mines. The results indicate a fairly robust model in terms of explanatory power. Recommendations on how the model can be used as a managerial tool are presented.

Jan 1, 1985

By Everett P. Partridge, J. E. Conley

Available statistics show that the demands of the American chemical industry for sodium sulphate have been increasing slightly in recent years. The supply from domestic sources, particularly in the form of byproduct salt cake from the acid manufacturers, has been tending to decrease this to the growing manufacture of synthetic acid. Both hydrochloric and nitric acids are being synthesized from their elements. The natural result has been that a smaller amount of salt cake is available. Simultaneously, the expansion of the kraft-paper industry, especially in the South, has brought about greater demand for sodium sulphate in that section. This demand is being met by domestic byproduct salt cake, by imported German sodium sulphate made from potash waste liquors, and by favorably situated domestic deposits of Glauber salts and the anhydrous salt, thenardite. No shortage of natural sodium sulphate exists in the United States, but usually such deposits occur in semiarid regions far removed from transportation facilities and from markets. Moreover, the major portion of the natural deposits is Glauber salt or mirabilite (Na2 504 • 10H20), which must be dried or dehydrated in order to meet consumer requirements. The water of hydration represents, roughly, 55 percent of the total weight of the crude salts and therefore has a very important influence on transportation costs, in many instances the cost of getting even the dehydrated product to market is the deciding economic factor. Therefore, the recovery of production of anhydrous sodium sulphate from plant-waste liquors or from natural brines of suitable composition might be economically feasible.

Mar 1, 1936