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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 D. A. Reynolds

[A few studies on the relationship of the fusion temperature of the ash of coke to that of the corresponding coal have been made on commercial high-temperature cokes. R. J. Rose3/ in 1921 compared the' fusion temperatures of the ashes of 10 coals and. the cokes produced from them and concluded tat they were in such close agreement that either figure could be used. More recently, Quarfort4/ found that the ash of coke fused at a somewhat lower temperature than that of the original coals As the ash of a coal and that of the coke produced therefrom have the same origin their chemical composition should be identical, provided that carbonization has not altered the inorganic, or ash-forming, constituents of the coal, and such alteration seems highly improbable. However, it has been shown5/ that coke is liable to contamination by iron during crushing and preparatory to sampling. Pieters6/ found that coke ash was cantaminated in this manner up to 0.4 percent. extraneous iron would lower the ash-fusion temperature because such iron may form ferrous silicate, which is readily fusible,7/ These results provide a basis for the prediction that the ash of coke will fuse at a lower temperature than that of the corresponding coil., especially if the fine grinding of the coke was done by rubbing surfaces of iron, as in a disk pulverizer or bucking plate.]

Jan 1, 1940

The Bureau of Mines found sulfur hexafluoride (SF6), released from a lecture bottle, to be an ideal gaseous tracer for studying mine ventilation systems. Air samples were collected in glass syringes and analyzed by electron-capture gas chromatography. In these studies, the lower limit of detection was about I part per billion by volume (ppb) of SF6 per part of air. Experiments conducted in a Pennsylvania limestone mine showed this technique useful in evaluating the effectiveness of auxiliary fans, measuring low flow velocities, probing the air circulating near a working face region where ventilation appeared to be poor, and estimating volumetric flow rates in airways of large cross-sectional area and having low flow velocities. This technique was also used in a western vein-type metal mine to measure the amount of return air being recirculated into the intake air due to leakage through old stoped areas.

Jan 1, 1974

By C. A. Hesse

The Quartz Hill Molybdenum Project, In Southeast Alaska, was the first mining project to attempt the permitting of a submarine tailings disposal system in the United States, since the passage of the National Environmental Policy Act of 1969 and the Clean Water Act of 1977. Over $20 million was spent by the project developer in baseline data gathering and In funding the preparation of the four Environmental Impact Statements and other environmental documents required at various stages of the project between 1977 and 1988. Because of the timing and a unique set of environmental, legal and regulatory requirements which applied to this project, innovative approaches were developed. This report describes those requirements and the developments, and gives a full historical account of the campaign for permitting submarine tailings disposal at Quartz Hill, until denial of the NPDES permit application by EPA in September 1 990. The extensive studies done for Quartz Hill suggested that under certain conditions the selection of submarine tailings disposal can be the overall environmentally preferred alternative for a mining project. The Quartz Hill story illustrates the complexity of the existing permitting structure and paints out the desirability of rationalization to achieve a more effective system.

Jan 1, 1993

Electrical trailing cables are frequently damaged in usage, especially on continuous minors, and because of their weight and damaged condition present a safety hazard to personnel required to handle them. The U.S. Bureau of Mines and FMC Corporation signed Contract No. HO 122011 in August 1971. One of the contract tasks was to study the feasibility of techniques to improve trailing cable support and handling of power cables on underground coal mine machinery and to design a cable-handling device for a continuous mining machine. This report presents the results of the feasibility study, describes the design for a proposed cable handling device and concludes with a recommendation for future action to construct a test rig to evaluate the cable reel system.

Jan 1, 1972

A pilot program was undertaken to evaluate a process developed by the U.S. Bureau of Mines to recover nickel, cobalt, copper and chromite from domestic nickel laterite resources. An existing five ton per day pilot plant was modified to accommodate treatment of laterite by the Bureau process, which employs reductive roasting, ammoniacal sulfate leaching, solvent extraction, and electrowinning to extract, separate, and recover nickel, cobalt and copper as high purity cathode products. Three distinct types of laterite i.e., limonite, saprolite and a mixture of limonite/saprolite were processed through the plant during three operating campaigns. Nickel cathode was made during all three campaigns, while cobalt cathode and chromite concentrate were recovered only during processing of limonite. Leach extraction of nickel and cobalt averaged 83 and 67 percent, respectively, while the overall recovery was 80 and 63 percent for nickel and cobalt, respectively. Initially, over-reduction of iron in the saprolitic calcine contributed to poor settling of the leached solids. This problem was overcome by careful control of reducing conditions and flocculant addition. An economic feasibility study was made for a 5000 TPD grassroots laterite processing facility scaled-up from pilot plant data. Estimated (+ 30) percent capital cost for a Nine and plant is $367 million with an estimated $103 million per year operating cost. The study indicates that low-grade domestic laterite may he processed with marginal profit- ability.

Jan 1, 1982

By L. D. Gent

This report reviews the current state of the art of remote control techniques for underground continuous miners. A delineation of aspects requiring additional data is presented. Also a summary and delineation are presented in overview form for the related section functions: roof control, haulage, ventilation, power supply and rock dusting. The automated remotely controlled continuous miner project is a long-range research effort. However, the program has been divided into intermediate steps resulting in incremental production increases throughout the program. Data are developed relating the impact of our proposed research and development accomplishments to potential productivity impact.

Jan 1, 1975

By W. P. Yant

A previous report of the Bureau of Mines dealt with the toxicity of dichlorodifluoromethane5, a new refrigerant that has a remarkably low toxicity. Continued research by the Prigidaire Corporation6 and toxicological experiments performed in the Laboratory of Applied Physiology of the University of Cincinnati7 revealed another organic fluoride, dichlorotetrafluoroethane, whose toxicity also appeared to be of a very low order and whose physical-and chemical properties make it suitable for refrigeration purposes. In addition to low toxicity, safety in its use is further enhanced by its physical properties, which permit the design of equipment that operates at comparatively low pressures and hence mitigates the dangers and problems of leakage. The investigation described in this report was performed by the Bureau of Mines at the request and with the cooperation of the Frigidaire Corporation.

Jan 1, 1932

By J. J. Wallace

This report describes the initial phase of Bureau of Mines research in the hydraulic mining of bituminous coal. The mining site and equipment are described, and the test procedures and results obtained with a bar-mounted monitor are given. Tests showed that hard Pittsburgh-bed coal can be mined hydraulically from a solid face at water pressures of 4,000 pounds per square inch.4 Coal was penetrated to a depth of 4 feet in 20 seconds with 225 gallons of water per minute coming from a 3/8-inch nozzle at 4,000 pounds per square inch pressure. Some difficulty was encountered in cutting the binders occurring in the coal; it was not possible Lu penetrate directly the overlying draw slate.

Jan 1, 1961

By T. M. Ruff

A prototype mucking machine designed to operate in narrow-vein stopes was developed by Foster- Miller, Inc., Waltham, MA, under contract with the U.S. Bureau of Mines. The machine, called a compact loader-trammer, or minimucker, was designed to replace slusher muckers in narrow-vein underground mines. The minimucker is a six-wheel-drive, skid-steered, load-haul-dump (LHD) machine that loads muck at the front with a novel slide-bucket system and ejects it out the rear so that the machine does not have to be turned around. To correct deficiencies of the tether-remote-control system, a computer-based, radio-remote-control system was retrofitted to the minimucker. Initial tests indicated a need to assist the operator in guiding the machine in narrow stopes. An automatic guidance system that used ultrasonic ranging sensors and a wall-following algorithm was installed. Additional tests in a simulated test stope showed that these changes improved the operation of the minimucker. The design and functions of the minimucker and its computer-based, remote-control system are reviewed, and an ultrasonic-sensor-based guidance system is described.

Jan 1, 1992

By R. T. Langland

Using a finite-element computer model, we have conducted an analytical study of roof behavior in a room-and-pillar coal mine. With standard engineering property in formation and a computer code developed for the Bureau of Mines to calculate roof sag, convergence, and roof-bolt load change, we have calculated the stability of roof-support systems and compared the computed data with experimental data collected during a field investigation at three test sites, one in a development area and two in production areas of a coal mine.

Jan 1, 1978

By Paul Hatmaker

"The Bureau of Mines recently has issued a general information circular covering briefly the origin and occurrence, properties, uses, exploitation, and marketing of diatomite. Since this publication was prepared, additional information has become available regarding one of the newer uses of diatomite — that as a filler in battery boxes. As this market is rapidly becoming one of the important outlets, a brief discussion of such use may be of interest.Diatomite is a mineral substance composed principally of the skeletal remains of diatoms. The skeletons of these microscopic flowerless water plants are made from silica present in the water in which these tiny plants live. The minute shells or ""casts"" accumu¬late in the bottom of lakes, ponds, or inland seas, and eventually become more or less consolidated into beds of diatomite.The uses of diatomite depend largely upon its peculiar properties. Diatomite is a highly porous substance and possesses marked absorptive powers. The large percentage of pore space makes the material very light in weight. It is relatively insoluble in most solutions.The largest deposits in the world are found in California, but diatomite occurs in many other Western States and also is found in a number of places along the Atlantic seaboard. Outside of the United States diatomite occurs in many countries; Algeria and Germany are among the largest producers.Usually diatomite is mined either by underground or open—cut methods. In some instances it may be dredged from lake and swamp bottoms. It must be dried prior to grinding or other preparation for market, and for many purposes must undergo a complex sizing and grading system for removal of such impurities as sand and clay and for classification of the material to the various sizes desired,"

Mar 1, 1931

By Jeffrey Johnson, Carl Sunderman, Ted Williams, Stephen Signer, Douglas Bayer

To measure the loading behavior of friction bolts, researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) installed strain gauges on the interior of friction bolts and developed a battery-powered miniature data acquisition system (MIDAS) that fits inside the hollow portion of the friction bolt. The advantages of this system are that it is protected from face blasts and eliminates the need for external wiring. Laboratory pull-out tests showed that friction bolts installed in a concrete block with resin were loaded to about 1.8 tons/ft of bolt length; bolts installed without resin were loaded to 1.3 tons/ft. Three strain-gauged friction bolts were installed at Hecla Mining Company’s Gold Hunter Mine, Mullan, ID, in the wall or rib of a mechanized cut-and-fill stope. The object of these tests was to establish an installation procedure for the bolt-and-MIDAS combination and to evaluate performance. The stope was advanced in three 15-ft increments and strains induced in the rock bolts by stress changes in the rock were recorded every 30 minutes. The MIDAS proved to be rugged enough to withstand the shock and vibration from nearby (5 ft) face blasting. Data from MIDAS showed that the friction bolt installed with resin was the most sensitive to each face advance. It showed a steady increase in loading to a maximum value of 1000 microstrain. The friction bolt installed without resin showed stick-slip behavior with loads to a maximum of 400 microstrain before the stope was completed.

This report includes a short history of uranium and its uses, mineralogy of common uranium minerals, and information on the use of electronic prospecting equipment and tests for detecting the presence of uranium. Details are given on geologically favorable areas and formations and practical methods of prospecting. Some information is given on the staking of claims, what lands are open to prospecting, and methods of securing mining rights. A forecast of the economic outlook for uranium is included. Appendixes give sources of additional information and a list of libraries where unclassified Atomic Energy Commission reports may be consulted. Because the increasing use of uranium by industry has revived interest in prospecting and exploration for this element, the Bureau of Mines has issued this report, which brings up to date and expands the subject matter of a hand- book on uranium exploration and production published in 1956.l

Jan 1, 1968

By D. A. Reynolds

A few studies on the relationship of the fusion temperature of the ash on coke to that of the corresponding coal have been made on commercial high-temperature cokes. H. J. Rose3/ in 1921 compared the fusion temperatures of the ashes of 10 coals and the cokes produced from them and concluded that they were in such hose agreement that either figure could be used. More recently, Quarfort4/ found that the ash of coke fused at a somewhat lower temperature than that of the original coal. As the ash of a coal and that off tie coke produced therefrom have the same origin their chemical composition should be identical, provided that carbonization has not altered the inorganic, or ash-forming, constituents of the coal, and such alteration seems highly improbable. However, it has been shown5/ that coke is liable to contamination by iron during crushing and grinding preparatory to sampling. Pieters6/ found that coke ash was contaminated in this manner up to 0.4 percent. Extraneous iron would lower the ash-fusion temperature because such iron may form ferrous silicate, which is readily fusible.7/ These results provide a basis for the prediction that the ash of coke will fuse at a lower temperature than that of the corresponding coal, especially if the fine grinding of the coke was done by rubbing -surfaces of iron, as in a disk pulverizer or bucking plate.

Jan 1, 1940

By Eleanor Abshire

THIS PUBLICATION is the third to be prepared as a result of a cooperative project by the Bureau of Ships and the Bureau of Mines for accumulating literature published on zirconium and hafnium. The undertaking also resulted in the establishment of an information center on zirconium and hafnium at the Bureau of Mines station at Albany, Oreg., for the use of research organizations and others. The present bibliography consists of references (with abstracts) to pertinent literature on zirconium. The first publication in this series was Information Circular 7771, Bibliography of Zirconium, published in April 1957. It consists of 969 abstracted reports and 645 U.S. and foreign patents. The second publication, called a supplement to Information Circular 7771, is numbered Information Circular 7830 and consists of 844 abstracted reports and 62 U.S. and foreign patents. It was published in October 1958.

Jan 1, 1962

By Michael Schmitz, Eugene Ahrenholtz, William A. Heitbrink, Jeanne A. Zimmer, Andrew B. Cecala, Ernest S. Moyer, Earle H. Andrews, Chris C. Coppock, John A. Organiscak

Many different types of surface mining equipment use enclosed cabs to protect equipment operators from health and safety hazards. The overburden removal and mining process can be extremely dusty and can cause excessive dust exposure. To study this issue, a cooperative research effort was established between the National Institute for Occupational Safety and Health, U.S. Silica Co., Clean Air Filter Co., and Red Dot Corp. in an effort to lower respirable dust levels in an enclosed cab on an older surface drill at a silica sand operation. Throughout this research effort, a number of modifications were incorporated into the drill's filtration and pressurization system, as well as in other areas, to improve its design and performance. An average cab efficiency of 93.4% was determined with gravimetric sampling instruments when comparing the outside with the inside cab dust levels on the final design. Although this study considered just one operation, the goal was to identify cost-effective improvements that could be implemented on all types of enclosed cabs to lower respirable dust concentrations. Two critical components for an effective enclosed cab system are having a properly designed, installed, and maintained filtration and pressurization system, along with a method for maintaining structural cab integrity, which allows the cab to be positively pressurized. Another important component is maintaining cab cleanliness. Although this research was originally directed toward the mining industry, it is also applicable to agricultural or construction equipment.

The condition of the domestic mining industry is obviously affected by the cycles in general business conditions. This study, the results of which are presented in a series of 78 charts, attempts to examine the interrelationships between the general business indicators and the major statistical measures for the base-metals industries during the cycles in the United States economy following World War II. For these industries the cyclical problem is perhaps less acute than the secular-trend problem. However, short-run fluctuations in production and employment do have very important impacts upon the welfare of the regions which derive a significant portion of their income from base-metals mining and processing industries. Any information concerning the normal patterns of development as the industries enter into a cyclical recession will permit better forecasts and perhaps help promote measures to alleviate the distress that occurs. Also, a systematic study of the comparative movements among the statistical measures during a series of cycles can bring to the fore the economic causation involved, and perhaps, after intensive study, can lead to a better method of short-range forecasting for these industries. This study has not fully achieved these aims. However, observations which significantly aid the interpretation of the current monthly statistics on these commodities are made, and some very general conclusions are drawn. The charts are presented so the interested people can examine them and draw additional conclusions. The charts refer specifically to cyclical analysis. The technique of indexing each cycle to its turning point effectively subordinates the longer term trend movements of the data. Thus, certain general conclusions flowing from this study and from the continuing economic research of the Office of Chief Economist will aid the reader by clarifying the frame of reference within which the charts should be examined.

Jan 1, 1961

By D. Harry Chambers

The Bureau of Mines, through a memorandum of agreement with the Department of Defense, conducted research to recover silver from aircraft scrap. Silver was recovered by an electrolytic method from stainless steel honeycomb sections separated from the aircraft. These sections had been constructed by sandwiching a stainless steel honeycomb core between stainless steel sheets and then brazing the assembly with a silver alloy. Over 300 pounds of silver was used in the B-58 bomber, concentrated in certain honeycomb sections of the aircraft. Following shredding of the aircraft parts, an average of 95 percent (ranging 67 to 100 percent) of the silver was recovered in a single electro-refining step. After the electrorefined product was magnetically cleaned, purity of the recovered silver was greater than 99.3 percent.

Jan 1, 1980

By Robert J. Dompe

The objective of this program was to develop a cost effective microprocessor-based electronic image sensor system for monitoring pit slope displacement to detect and/ or predict impending slope failure in surface mines. A background study and data analysis yielded a performance specification for candidate Video Slope Monitoring Systems. A design concept was developed based on using a pair of solid state video cameras located on precision pointing assemblies. The digital images from the cameras are compared and, using electronic triangulation, slope topology is calculated. The current and past locations of operator selected features are compared to determine pit slope displacement. A proof-of-concept test was performed using a laboratory model of a pit slope. Based on the successful results of that testing it is recommended that an in-mine evaluation be performed using a full-scale prototype Video Slope Monitoring System.

Jan 1, 1982