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By Henry M. Harris

Low-carbon shales from 65 deposits and 11 sources of coal-mine waste in western Oregon and Washington were tested in a rotary kiln for their suitability as raw material for expanded aggregate. Shales from 41 sources bloated enough to produce crushed, expanded aggregates, weighing less than 65 pounds per cubic foot in the preliminary tests. The samples were judged on the basis of processing qualities, physical properties, and size and uniformity of the source. Nine low-carbon shale deposits and three coal-mine waste sources were selected for more extensive bloating tests and for examination of the expanded aggregates in concrete shapes. Composite samples from these 12 sources and from 2 commercial operations, when processed for testing in concrete shapes, had bulk densities ranging from 37.S to 72.9 pounds per cubic foot. Damp-cured concrete shapes made with these aggregates had bulk densities ranging from S6 to 119 pounds per cubic foot, and all but three of the lightweight concretes had crushing strengths ranging from 3,270 to 6,810 p.s.i. Properties of the lightweight concretes were compared with those of concrete shapes made with commercial aggregates, and with sand and gravel.

Jan 1, 1962

By Joseph A. Corgan

The river- or dredge-coal industry of Pennsylvania is conducted on many of the rivers and creeks that drain the Pennsylvania anthracite fields. Coal thus recovered found its way into the streams as coal was being prepared for market by the anthracite industry proper, in the northeastern part of the State. The Principal rivers draining; the fields, those where dredging is taking place, are the Susquehanna, Schuylkill, and Lehigh. Several creeks - the Shamokin, Mahanoy, Wiconisco, and Swatara - also are productive sources of river or creek coal. Operations along the streams cover a wide territory, and along the Susquchanna alone; dredges are recovering coal for about 160 miles. Anthracite was a significant factor in the early industrial development of the United States. Industry used it to generate steam, and railroads used it as fuel for locomotives; but it probably was most important industrially in the smelting of iron ore. For more than a hundred years homes have been heated with this fuel. From the beginning of mining in 1807, to 1940, more than 4 billion net tons of anthracite had been prepared and shipped to market. In the preparation process much of the smaller-size coal and refuse found their way into rivers and creeks which carried the material many miles. This study is concerned with the recovery of that anthracite from those rivers and creeks.

Jan 1, 1942

By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules3 include 13D for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pittsburgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer4 of the respirator and at his expense. If the device meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By R. H. Schutz

TO ASSIST users in the selection of reliable and satisfactory respiratory protective devices, the Bureau of Mines bas established five schedules of minimum performance requirements for the approval of respirators. The current revisions of these schedules include 130 for self-contained breathing apparatus, 141F for gas masks, 19B and the amendments to 19B for supplied- air respirators, 21B for dust, fume, and .mist respirators, and 23B for chemical cartridge respirators. Copies of these schedules may be obtained from the Bureau of Mines, Publications Distribution Section, 4800 Forbes Avenue, Pitts- burgh, Pa., 15213. Approval tests on respirators are performed only at the request of the manufacturer of the respirator and at his expense. If the deice meets the approval requirements, a certificate of approval is granted on the complete respirator. This certificate states that as long as the respirator is manufactured as originally approved, or in accordance with any changes covered by an extension of the original approval, the manufacturer may advertise and sell his respirator as being approved by the Bureau of Mines. Many industries and regulatory agencies require that respirators approved by the Bureau of Mines he used where respiratory protection is needed. The Bureau of Mines, however, has no regulatory power over the use of the respirators that it approves. It acts as an impartial testing agency to insure the availability of suitable and safe respirators.

Jan 1, 1966

By Ernest W. Johnson

In most underground iron mines in the Lake Superior district the active workings are at considerable depth. When additional openings into such. nines are needed, operating officials are eager to discover more efficient methods of constructing them. In recent years, openings into two mines in the district were made by the borehole method,-which employs chilled-iron shot as the cutting medium. Others were made by the churn-drill method, in which pilot hole is churn-drilled and subsequently reamed to a desired but relatively small diameter. Both methods are comparatively new and unique, at least in some phases and in their application.

Jan 1, 1946

By Steven K. Ruggieri

This report describes the operation and maintenance of the Mobile Inert Gas Generator for use in the Remote Sealing System for fighting underground coal mine fires. Seals are emplaced in mine passageways between the fire zone and the rest of the mine isolating the fire zone from the mine. The seals consist of fly ash that has been pneumatically conveyed via inert gas through a borehole connecting the surface and the passageway, Inert gas is used as the fly ash seal transport medium (instead of fresh air) since the introduction of large volumes of fresh air in the vicinity of the fire zone would be undesirable. The inert gas generation equipment is mounted on two flatbed trailers, the "hot" trailer and the "cold" trailer. The hot trailer contains the combustion and cooling equipment. The cold trailer contains the moisture removal and compression equipment necessary to convey the fly ash. The system is self-sufficient and requires only fuel and fly ash deliveries. The Inert Gas Generator has been thoroughly performance tested and has been operated in the field for approximately 200 hr. The system was employed in the demonstration of the entire Remote Mine Sealing System at the Jenney Mine in the Fall of 1978. The system is currently available for fighting any future underground coal mine fires.

Jan 1, 1980

By Stanley P. Jacobsen

Samples of fine coal refuse were obtained from 11 coal preparation plants throughout the United States. These samples were characterized by ash analysis, particle size, and mineral composition. From the characterization, geographical locations, and the dewatering equipment being used by the plants, five sites were selected for obtaining bulk fine refuse samples. The selected coal preparation plants were using for final dewatering thickeners followed by: a vacuum disc filter, a filter press, a belt press filter, a centrifuge, and a settling pond. None were using thermal drying. The moisture content of the final cake varied from approximately 23% to 50% depending upon the feed material, flocculant addition, and the type of equipment. The filter press gave the lowest moisture content followed by a belt press and then either a centrifuge or vacuum filter. The centrifuge products were all dried to an approximate 5% moisture in a thermal dryer.

Jan 1, 1981

By Thomas M. Barczak

This U.S. Bureau of Mines report is intended to assist coal mine operators in the selection of longwall supports by providing advanced guidelines for performance testing and standardized test documentation to facilitate support comparisons. These advanced guidelines culminate in a series of proposed tests to evaluate (1) support resistance characteristics, (2) stiffness characteristics, (3) leg mechanics, (4) stability, (5) load transfer mechanics, and (6) structural integrity. The Bureau has conducted extensive studies on shield mechanics to identify boundary conditions that induce loading in support components, which is often not included in current testing techniques. This report discusses influential parameters that affect support behavior and provides insight into how components are loaded and what conditions produce the most severe loading. Testing philosophies and techniques in both active and static frames are discussed. Proper methods for determining support resistance are described and instrumentation requirements for advanced performance testing are provided.

Jan 1, 1989

By Ludwig Schmidt

This report, the second of a series, presents the results of laboratory corrosion studies which were made in connection with a one-year test on aluminum lease tanks conducted by the United States Bureau of Mines. Part I of the report contains the results of the field teats.5 The studies were made on an oil lease in a so-called "sour district," near Borger, Tag., where free hydrogen sulphide accompanied the production of oil, gas, and salt water. Steel tanks previously used on the lease had suffered severe corrosion, because steel is inherently susceptible to attack by hydrogen sulphide. Because of the high resistivity of aluminum to the action of hydrogen sulphide, it Was believed that this metal had promising possibilities as a material for the construction of lease tanks in "sour districts." The results of the one-year field teat proved that aluminum lease tanks will withstand corrosion by hydrogen sulphide, but it was found that aluminum was susceptible to attack by salt water, which was invariably present in certain portions of the tanks, and that hydrogen sulphide accelerated this salt-water corrosion in an indirect manner, as will be explained hereinafter. In order to study corrosion conditions encountered in the tanks during the test period, a laboratory was maintained at the site of the aluminum lease tanks.

Jan 1, 1931

By D. A. Paice

A portable calibrator to check tie trip setting of dc circuit breakers within an accuracy of +5% has been developed for the Bureau of Mines. It operates from a 300 volt dc trolley wire to provide controlled current pulses of 120 milliseconds duration and continuously adjustable from 1400 to 3600 A. These current pulses enable a breaker dc trip current to be determined and subject the contacts to full current rating. The equipment is simple to use and weighs 86 pounds. Connections are made with protected, clamp-on leads which are separately connected and weigh about 22 pounds. An accurate calibration procedure takes less than 5 minutes to complete.

Jan 1, 1978

By H. L. Gilbert

Zircon sand may be reacted with sodium hydroxide at 600° C. to form sodium zirconate and sodium silicate. Sodium zirconate is water insoluble and so may be washed free of sodium silicate. The sodium zirconate may then be converted to zirconyl chloride by the action of hydrochloric acid and the zirconyl chloride crystals separated by cooling the solution. This approach produces zirconyl chloride of satisfactory purity with less cost than is involved in buying anhydrous zirconium chloride and converting it. A proposed design for a plant is given, INTRODUCTION This work was conducted by the Rare Metals Branch as a part of research on zirconium at the Bureau of Mines Northwest Electrodevelopment Laboratories, Albany, Oreg., under the guidance of S. M. Shelton, Regional Director. The work was supervised by W. W. Stephens, head of the Rare Metals Branch (now with Carborundum Metals Corp.).

Jan 1, 1954

By R. E. Heithecker

[The separation of enormous quantities of water produced with the oil in some West Texas fields necessitated. the use of special equipment other than the regular lease tanks. Several methods Were used with varying degrees of success. They include, the water-trap, hay tank and gun barrel, gun barrel and settling tank, chemical, and electrical-dehydration methods. The water trap which has been used extensively in the Hendricks field, and in some instances has been installed in the Yates field separates the water' and. oil under high pressure before tile liquid and gas pass through the flow ?bean. The first trap was constructed and installed by the Southern Crude Oil Purchasing Co. in July, 1928. By July, 1929, approximately 300 traps were in use.]

Jan 1, 1932

By R. E. Heithecker

The separation of enormous quantities of water produced with the oil in some West Texas fields necessitated the use of special equipment other than the regular lease tanks. Several methods were used with varying degrees of success. They include the water-trap, hay tank and gun barrel, gun barrel and settling tank, chemical and electrical-dehydration methods. The water trap which has been used extensively in the Hendricks field, and in some instances has been installed in the Yates field separates the water and. oil under high pressure before tile liquid and gas pass through the flow beam. The first trap was constructed and installed by the Southern Crude Oil Purchasing Co. in July, 1928. By July, 1929, approximately 300 traps were in use. Treating cut oil by running it through a hay tank was done quite extensively in the Roberts-Settles field, Howard and Glasscock Counties, Tex., and later the method was used in the Hendricks field. In July, 1931, there were 37 hay tanks in the Roberts-Settles field, treating the oil from 123 wells. The cut oil frequently was made acceptable to the pipe-line company by running it through the hay tank. In some instances, however, it was necessary to heat the oil, and occasionally both heat and chemicals were used before complete separation of the oil and water was obtained.

Jan 1, 1932

By D. Harrington

Part III-B, presented in this circular, completes the series reviewing the literature on effects of breathing dusts with special reference to silicosis; it includes data on the status and cost of compensation for silicosis in the United States and several foreign countries and a summary and general conclusions covering the whole series. Parts I, II, and III-A of the series have been issued as Information Circulars 6935, 6840, 6948 , and 6957; Part I defines and classifies dusts, indicates sources of exposure, and describes the physiological effects of breathing dusts; Part II-A discusses the principal dust factors producing pulmonary pathology and methods of determination of dust in air; Part II-B presents data on the engineering and medical control in the prevention of dust diseases and general recommendations for their control in industry; and Part III-A deals with the economic and legal aspects of dust diseases in industry.

Jan 1, 1936

By Harold J. Bennett

The purpose of this study was to develop methods for the financial evaluation of mineral deposits. This includes the selection of the best alternative mining and processing methods and production rates. This was done by performing a financial evaluation through computer simulation using sensitivity and probabilistic risk analysis. The criterion used to measure the relative advantages of these investment and operating alternatives is the discounted-cash-flow rate of return. Included is a description of the theory and methods used in the probabilistic analysis approach, which is based on the premise that the expression of a range of values in establishing an estimate for a parameter is more realistic than the choice of a single value. Numerous simulations are made using randomly selected values of the input parameters resulting in a frequency distribution of the rates of return and their relative probability of occurrence. The sensitivity analysis method is described and combined with the probabilistic analysis to interrelate mineral reserves, capital investments, operating costs, and production rates. The ability to vary these input parameters on successive runs has permitted the selection of the best alternative mining and processing methods and production rates for a given mineral deposit. For illustrative purposes the evaluation of a mineral deposit was performed using three alternative mining and processing methods at three different quantities of resources and various production rates and prices. The computer program used in this analysis was written in FORTRAN II for maximum compatability and should run without modification on most computers having BK (8,000-word) core memory, a card reader, and printer (120 characters per line).

Jan 1, 1970

By Lester J. Crow

A preliminary survey was performed to investigate the impregnation of relatively weak, porous volcanic tuff and a relatively strong, dense sandstone with five different monomers. Increases in compressive strengths by factors of 2 to 5, and elastic moduli by factors of 2 to 3.5, are reported for natural rocks (tuff., sandstone, dacite), which were impregnated with five monomers (methyl methacrylate; chlorostyrene; 40 percent TMPTMA-60 percent styrene; 40 percent TMPTMA-60 percent chlorostyrene; 60 percent polyester-40 percent styrene); polymerization took place after monomers were forced into the rock. Impregnation was performed (1) by pressurizing rock specimens from one end, or (2) by a vacuum-soak operation. Polymerization was accomplished by either radiation or chemical initiation techniques. Strength improvement is dependent on (1) the type of monomer used, (2) the amount of polymer incorporated into the rock, and (3) the degree of water saturation of the rock. Water saturation strongly reduced the effectiveness of the method for the polymer systems tested. The more viscous monomers (for example, 60 percent polyester-40 percent styrene) were more effective in displacing the water from the rock, and compressive strengths of wet rock were doubled with these systems. Water saturations ranging from 25 to 100 percent of maximum saturation gave essentially identical results. Further tests on other types of mine rock; including shale and coal, are planned. Water-compatible polymer systems should be developed, or present systems should be suitably modified. For application to tunnel stabilization, design studies evaluating the improvement in rock strength and its influence on the support system are also recommended.

Jan 1, 1971

By John Nagy

Dust explosion data obtained in laboratory tests by the Bureau of Mines are presented for 181 miscellaneous materials that present an explosion hazard. Data are given also for 50 dusts that present primarily a fire hazard and for 88 dusts that did not present an explosion hazard.

Jan 1, 1968

The strike of the Canadian asbestos miners entered its seventh month with increasing signs of early termination. Both unions are in the midst of heavy negotiations with management, and an optimistic industry source predicted that work would resume by October 1. Recession recovery in some segments of the asbestos manufacturing industry is being impeded by lack of fibers, CADMIUM - On September 9, St. Joe Minerals Corp. reduced the price of cadmium metal to $2.75 per pound. The producer price bad been uniformly quoted at $3.00 per pound since June 26, 1975. Subsequently, Amax, Inc. and National Zinc Co. reduced their prices to $2.50 per pound. By mid-September all five U.S. cadmium producers were marketing the metal at $2.50 per pound.

Jan 1, 1975

By J. D. Davis

THIS REPORT gives results of an investi¬gation of the carbonizing properties of coals from Pittsburgh bed, Jamison No. 9 mine, Marion County, W. Va., and from Upper Freeport bed, Bull Run No. 1 mine, Preston County, W. Va. The study included Bureau of Mines-American Gas Association tests at 800° and 900° C. and various chemical and physical tests designed to evaluate the plastic, expanding, and agglutinating properties of coal. A blend of each coal was carbonized in the 500-pound slot oven. The carbonization sample of Pittsburgh coal contained 2.7 percent moisture, 35.8 percent volatile matter, 54.4 percent fixed carbon, 7.1 percent ash, and 0.9 percent sulfur. It contained 60.9 percent fixed carbon on the dry, mineral-matter-free basis and had a heating value of 14,780 B. t. u. per pound on the moist, mineral-matter-free basis. It therefore ranks as high-volatile A bituminous and was blended with low-volatile Pocahontas No. 3 coal. Upper Freeport coal contained 2.8 percent moisture, 27.7 percent volatile matter, 60.9 percent fixed carbon, 8.6 percent ash, and 1.0 percent sulfur, as carbonized. It contained 69.5 percent fixed carbon on the dry, mineral-matter-free basis and therefore ranks as medium-volatile bituminous. It was blended with high-volatile A Pittsburgh coal from Allegheny County Pa.

Jan 1, 1952

By G. J. Hundman

Control of respirable dust produced by auger type continuous mining machines is normally attempted by water sprays from fixed nozzles mounted on the frame of the machine. In tests conducted under this contract, a 'wet auger' system was used, where the spray nozzles were mounted on the rotating auger itself. The tests were conducted at the Hunter mine of Smith and Stover Coal Company using a Jeffrey 1.00L auger miner. Operating the mining machine in the wet auger mode, it was found to produce 47 pct less respirable dust than when the fixed conventional sprays were used. On section dust levels were reduced too 3.5 mg/m3 which is equivalent to approximately 2.0 mg/m3 for a full shift portal to portal sample. The major difficulty that had to be overcome was the development of a simple reliable water transfer mechanism to get the water into the rotating augers. This was successfully achieved by the development of a water-through-the-shaft water system. This system can be retrofitted to existing machines and is available in kit form.

Jan 1, 1977