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By Edwin M. Murphy

Methods are described for filling underground cavities remotely with dry material pneumatically injected through a borehole to seal openings, prevent air movement, and reduce subsidence; this often brings underground fires under control by limiting the access of air. Large-scale tests were made in the Bureau of Mines Experimental Coal Mine, Bruceton, Pa., in an operating mine, and in an abandoned Pennsylvania mine. Supplemental trials were made aboveground in galleries and in the laboratory. The parameters studied include horizontal and inclined passageways, obstructions in the entry, water leakage into the borehole, dry material, and grout and slurry mixes. The materials studied were fly ash, crushed and pulverized limestone, and sand. Best results were obtained with dry fly ash, though satisfactory seals were obtained with the other materials. When a borehole is dry and ends at an open void, casing is not necessary. If more than 5 gpm of water flows in the borehole, if the void contains loose debris, or if coarse material is injected, a material feedpipe should be inserted through the borehole. Fly ash was most suitable for remote filling because of its low angle of repose (8°) and its good flow characteristics. The depth of borehole through which the fly ash is injected has no appreciable effect on the filling operation.

Jan 1, 1968

By David Schlain

A small alumina reduction cell with a graphite crucible and boron nitride liner was developed by the Bureau of Mines as the initial phase of a study of the reactions which occur in the reduction of alumina by the Hall-Heroult process. Operating conditions in the cell such as temperature, time, current density, electrolyte composition, and electrode materials may be varied easily. Aluminum was produced in the cell at a current efficiency of about 75 percent and a cell voltage of 2.7 volts. Although the data are not wholly conclusive, the operation of the cell did not appear to be greatly affected by large changes in temperature, electrode spacing, current density, and alumina concentration in the electrolyte.

Jan 1, 1963

By Edward G. Cunney

Track in underground bituminous coal mines was investigated, and technology was taken from other industries in order to obtain information on conditions that impair the safety and efficiency of the track and to develop guidelines and useful information on the construction, inspection and maintenance of mine track. Volume 1 contains information on the investigations, observed track conditions, useful technology from railroads and other industries, derivations of track condition descriptors and recommended limits, conclusions, and recommendations. Volume 2, Guidelines, contains recommended standards and practices for mine track. It includes the relation of track conditions to safe speeds; descriptions and limits for measurable track features such as gage; descriptions of conditions for track components that are normally not measurable, such as subbase soils; construction requirements and techniques, inspection requirements and methods; and methods for managing and performing track maintenance work. As a research product, it does not repeat the summary or derivations. Volume 3, Inspection Handbook, summarizes recommended standards and procedures from Volume 2 and provides related information for' ready reference by inspectors in the mines. As a research product to be used in mines, it does not repeat the summary, derivations or references.

Jan 1, 1977

By Edward E. Johnson

The U.S. economy boomed in 1965, completing its fifth consecutive year of expansion. Although the advance was somewhat irregular, previous records for production, sales, employment, and income were topped. During the first few months of 1965, as the economy recovered from the depressing effects of the automobile strikes of late 1964, increases were unusually large. The gains moderated in early spring, but were stimulated at midyear by sharply rising capital outlays, excise tax cuts, in? creased Social Security payments, and accelerated Viet-Nam defense expenditures. Gross national product (GNP) in cur-rent dollars rose $49.5 billion or 7.8 percent, to a total of S681.2 billion. In constant dollars (effects of price changes eliminated), GNP increased 5.9 percent, a rate considerably higher than the historical postwar annual average growth of 3.5 per-cent. Demand increased in most final markets and was especially strong for business fixed investment and consumption expenditures. With the exception of construction, most of the increases in GNP were real, since prices increased less than 2 percent.

Jan 1, 1966

By M. D. Aldridge

This document reports the results of a two-year research effort aimed at improving communication systems used in coal mines. This work was conducted under a program whose original goal not only involved the development of practical and effective electronic systems for operational communications, but also for monitoring, at a central location, remote instruments at key positions in a mine. About half way through the originally proposed three year effort, the program was redirected to phase out the communication effort at the end of two years and to concentrate the program" resources on the investigation of new monitoring system concepts developed by this research. Thus, the work reported here is incomplete relative to the originally pro- posed program. However, the work was carried to the point of providing sufficient evidence to aid in the comparison of certain new communication concepts. For the concepts chosen for this study, the work was stopped short of hardware development and field testing, Several reports in the form of Master's theses and a Doctoral Dissertation have resulted from this research. They each report in considerable detail the results of several individual" contributions to this program. In preparing this report, an attempt has been made to provide a complete description of the significant results but with- out burdening the reader with the minute details. These more detailed reports are referenced heavily for the convenience of those interested. PRESENT COMMUNICATION METHODS Two types of communication systems are presently used In coal mines. They are: 1, Various forms of telephone systems, and 2. Carrier current radio systems using the trolley line as the interconnection circuit. Carrier current radio is used almost exclusively for control of rail trafflc by the dispatcher. Almost all other communication uses the telephone system, Telephone lines generally extend to areas where trolley lines are not present such as the outside offices and warehouse. Therefore the telephone system provides the primary means of voice communication. Telephones - Telephone systems employed in American coal mines fall into three categories. 1. Paging type telephone systems - these systems have individual stations which use battery powered transistor audio amplifiers to boost signal levels for normal communication. When in the page mode,

By Robert S. Sanford

The demand for aluminum for military use during World War II called for an expansion of aluminum production in the United States A large part of the bauxite (the normal ore of aluminum) consumed in this county comes from Netherlands Guiana, South America. During the war, enemy activities were at times a serious threat to the flow of bauxite to the United States. The need for aluminum. stimulated the investigation of domestic deposits of bauxite and emphasized the wisdom of studying other aluminous materials, such as high-alumina and diaspore clays, to determine their possible use as aluminum ores. The occurrence in Pennsylvania of high-alumina flint clays and nodular diaspore clays has been known for many years. Several companies are mining these high-alumina, low-iron (less than 3 percent Fe2O3) clays and using them for the manufacture of refractory brick. Most of the production has come from Clearfield County, but clay deposits arc known also in Cambria, Centre, Clarion, Clinton, Indiana, Jefferson, Somerset, and Westmoreland, Counties.

Jan 1, 1949

By W. Beckering

In characterizing tars obtained by the low-temperature carbonization of North Dakota lignite, infrared spectra have been an invaluable aid in both qualitative and quantitative examination. Quite, early in the tar-research program of the Federal Bureau of Mines it became evident that the small number of published spectra available for hydroxy-aromatics would be inadequate for comparative purposes when dealing with the wide range of compounds present in coal tar; therefore, compiling a catalog of spectra was begun as a continuing part of the tar program. Because these spectra should be valuable to other investigators in this and related fields, they are being presented in these reports. This supplement to the original publications presents the spectra (figs, I to 32), representing 32 compounds, largely phenolic materials. The major problem of this project has been the availability of materials for examination. Most of the compounds included in this supplement were synthesized at the Bureau of Mines Lignite Research Laboratory. Some were obtained from commercial sources, whereas the compound 2'-hydroxy-l-phenylnaphthalene was synthesized at the Bureau of Mines laboratory in Bruceton, Pa. The spectrum of 2-ethyl-4-methylphenol, figure 32, is a correction of the spectrum presented as figure 26 in the original reports

Jan 1, 1961

By Sandeep K. Sharma

The U.S. Bureau of Mines has been investigating new techniques to improve the of mineral to recover water lost in the waste slurry, and to produce dewatered solid dewatering s suitable for disposal. As part of this investigation, a study was undertaken to investigate the feasibility of dewatering Alaska placer effluent. Based on the laboratory tests, preliminary field tests were conducted on three placer mines in Alaska. At these mines, the water recovered from the placer effluent (250 to 23,000 NTU) exhibited turbidities of 20 to 240 NTU. In the second year of the project, a large-scale dewatering unit was set up at a mine located in the Livengood district. The feed, at flow rates up to 935 gpm, was mixed with dilute PEO solution in a flexible plastic hose with and without static mixers. Feed to the dewatering unit generally ranged between 300 and 26,500 NTU and required PEO dosages of 0.02 to 0.14 lb per 1,000 gal to produce water from the screen underflow with turbidities of 20 to 50 NTU. During this period, a small unit was also operated at Dow rams of 10 to 25 gpm at sewn sites throughout Alaska, with the effluent from four of the sites being dewatered successfully.

Jan 1, 2010

By Edward L. McHugh

Twelve properties in the Riverside Mountains have moderate to high potential, for silver, gold, copper, and molybdenum. Six properties in the Big Maria Mountains have moderate potential for zinc, lead, copper, silver, iron ore, and limestone. The Big Maria Mountains also have occurrences of building stone. Four properties in or near the study area have low-grade gold-silver-copper resources totalling more than 300 thousand tons (270,000 t). An estimated 29 million tons (26 million t) of limestone and dolomite, and 620,000 long tons (630,000 t) of iron ore are in the Big Maria Mountains section of the study area. INTRODUCTION The Big Maria Mountains Wilderness Study Area covers about 50,538 acres (20,453 ha) near the Colorado River in eastern Riverside County, California (fig. 1). The study includes portions of both the Big Maria and Riverside Mountains. It lies north of Blythe, California and south of California Highway 62 in the Mojave Desert province of the California Desert Conservation Area. The study area consists of two mountain ranges surrounded mostly by broad alluvial slopes or bajadas. It extends for 25 mi (40 km) from the Riverside Mountains on the north, to the south end of the elongate Big Maria Mountains.

Jan 1, 1982

By P. G. Bennett

The Bureau of Mines developed a process using ion exchange to recover cobalt from spent copper leach solutions. A preliminary economic evaluation of the process indicated that about one-third of the capital cost was attributed to the total resin inventory, and one-third of the operating cost was required for reagents to remove iron from the ion-exchange eluates. An agitated Pachuca elution system was investigated in place of a fixed-bed elution system. The Pachuca system reduced the resin inventory by 27 pet when compared with the fixed-bed elution system. Processing fresh spent copper leach solution reduced the resin inventory by 20 pct and resin iron loading by 80 pct. Reagent requirements for removing iron from the eluates were decreased because less iron was extracted. The Pachuca system, along with processing fresh spent copper leach solution, reduced the total resin inventory by 47 pct. A revised cost evaluation of the cobalt recovery process was obtained to determine the effects of these process modifIcations. The estimated total capital cost for a plant processing 10,000 gpm of spent copper leach solution containing 26 ppm Co was $23.1 million. With credits for nickel, zinc, and copper byproducts, the estimated net operating cost was $5.10/lb of cobalt.

Jan 1, 1988

By J. V. Batty

Various ores from deposits in the Boulder Dam Recreational Area, Clark County, Nev., were submitted for ore-dressing tests as part of the Bureau of Mines studies of western manganese ores. The Virgin River manganese deposit is situated on the Virgin River arm of Lake Mead, 5 miles from Bonelli's Point, which was formerly the junction of the Virgin and Colorado Rivers. It is 20 miles from Overton, Nev., and 26 miles from Boulder City, Nev. The ore body, composed of wadlike manganese in a tuffaceous gangue, is a flat-lying bed overlain with beds of gypsum and basalt. Two ore samples were submitted by engineers of the Bureau for ore-dressing investigation. Low-grade sample 1 was a composite of channel samples cut from outcrops of the ore body; sample 2, of intermediate manganese grade, was taken from the dump-at the exploratory shaft sunk by the Bureau. The Boulder City manganese deposit is situated in the Boulder Dam Recreational Area -3 miles southwest of Boulder City. The ore body is a manganiferous gypsum bed 32 feet thick, slightly inclined from the horizontal. The ore sample submitted-by engineers of the Bureau for-testing was taken from channel cuts in the walls of the shaft, which cuts through the bed vertically.

Jan 1, 1948

By Stanton L. Tainter

As a part of a wartime program to aid in the development of known ore bodies and in the discovery of hitherto unknown deposits of strategic minerals, the Bureau of Mines investigated the feasibility of diamond-drilling the Christmas copper deposit, in Gila County, Ariz., to increase the reserves of milling ore. Upon recommendation of the examining engineer, drilling was begun in September 1942, from the bottom (770) level of the mine. One month later, in cooperation with the Bureau, the Federal Geological Survey started geologic mapping of the mine workings. Since extensive and costly development would be required, the War Production Board concluded that ore below the bottom level could not be mined at that time because of the wartime shortages of equipment and man-power. In January 1943, drilling was moved to the 300 and 400 levels to locate reserves readily accessible for continued production of fluxing ore. This drilling, which was under the supervision of L. G. Marshall, was completed in January 1944.

Jan 1, 1948

By R. D. Brown

This Bureau of Mines report describes a new methodology for identifying and sorting scrap metals using two modern portable instruments: a thermoelectric sorter and a hand-held emission spectroscope. The method, tested on a 27-sample stainless steel and superalloy array, makes it possible to group and/or identify a typical mixture of high-value metal scrap in two or three steps, whereas as many as seven or eight steps are needed to perform the same separations using chemical spot tests. A portable fluorescent X-ray analyzer identified 19 of the 27 alloys in the sample array by name or type; these alloys are included in the microprocessor memory. The remaining alloys were identified by using the analyzer in its elemental analysis mode and comparing the results wit.h alloy specification chemistry.

Jan 1, 1984

By John C. Gagliardi

The U.S. Bureau of Mines, in cooperation with Carter Mining Co., conducted vibration tests of four off-road vehicle seats. The purpose of the tests was to determine which seat provided the best vibration attenuation under laboratory conditions. Laboratory tests were constructed to simulate the mining vibration environment within the limitations of the test equipment. The acceleration test levels and corresponding response of the seats were low compared to ISO 2631's fatigue-decreased-proficiency time limits. Two of the seats employed mechanical suspensions and two seats employed air suspensions. The seats were tested using a 22,241-N (5,000-lbf) electrodynamic shaker. Mechanical suspension seats were tested with various preload-to-mass ratios (PMR's) and cushion densities. Air suspension seats were tested with various air pressure levels and seat cushion densities. Air suspension seats provided good vibration attenuation if pressurized greater than 552 kPa (80 psi). Mechanical suspension seats' attenuation performance decreased if the PMR exceeded 9.8. Seat cushions of lower density provided less vibration damping.

Jan 1, 2010

By D. Harrington

Most of those in the Health and Safety Branch, Bureau of Mines, necessarily participate in activities associated with essentially all phases of the mineral industries, including coal and noncoal mines, quarries, smelters, metallurgical plants, and various petroleum operations. One of the strictly war activities of the branch - the Explosives Control Division, which administers the Federal Explosives Act of December 26, 1941 - has functions that require contacts not only with nearly all phases of the mining and allied industries but also with those engaged in scores of other occupations that manufacture, store, use, or possess explosives, or many of the ingredients of explosives. The field men of the Health and Safety Branch (approximately 300 in number) Are occupied full time in health and safety activities and annually make thousands of contacts with people in the mineral industries as well as the plants in which they work. From these they formulate several thousand written reports containing sources of thousands of conclusions and recommendations aimed at reduction of health end safety hazards in these industries. Although such activities have been greatly increased during the war and immediate pro-war periods, they have been in effect to a considerable extent since the Bureau of Mines was created in 1910.

Jan 1, 1944

By A. F. Baker

Tests were conducted in commercial foundries to determine the suitability of calcined anthracite as a cupola fuel. The calcined anthracite performed satisfactorily at two of the three foundries where iron-melting tests were conducted. Performance at the third installation was unsatisfactory because metal temperatures deviated widely and, in general, were lower than is desirable for the type of castings being made.

Jan 1, 1963

Crystalline silica is the scientific name for a group of minerals composed of silicon and oxygen. The term crystalline refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating pattern. This group of minerals has shaped human history since the beginning of civilization. From the sand used for making glass to the piezoelectric quartz crystals used in advanced communication systems, crystalline silica has been a part of our technological development. Crystalline silica's pervasiveness in our technology is matched only by its abundance in nature. It's found in samples from every geologic era and from every location around the globe. Scientists have known for decades that prolonged and excessive exposure to crystalline silica dust in mining environments can cause silicosis, a noncancerous lung disease. During the 1980's, studies were conducted that suggested that crystalline silica also was a carcinogen. As a result of these findings, crystalline silica has been regulated under the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard (HCS). Under HCS, OSHA regulated businesses that use materials containing 0.1 or more crystalline silica must follow Federal guidelines concerning hazard communication and worker training. Although the HCS does not require that samples be analyzed for crystalline silica, mineral suppliers or OSHA-regulated businesses may choose to do so if they wish to show that they are exempt from the requirements of HCS. Because crystalline silica is an extremely common mineral and the HCS will affect many mineral commodities, it is important then, that there be as clear an understanding as possible of what is and what is not crystalline silica, and where it is found and used, and how it is qualitatively and quantitatively identified. This primer is an attempt to accomplish this in as nontechnical a manner as possible. This primer will examine crystalline silica. Part I will describe, in nonscientific terms, what crystalline silica is and how we come in contact with it. Part" will discuss the regulatory decisions that have created new interest in this ancient and widespread substance and will present a nontechnical overview of the techniques used to measure crystalline silica. Because this primer is meant to be a starting point for anyone interested in learning more about crystalline silica, a list of selected readings and other resources is included. The detailed glossary, which defines many terms that are beyond the scope of this publication, is designed to help the reader move from this presentation to a more technical one, the inevitable next step.

Jan 1, 1992

By R. D. Wilson

Ten to twelve million tons of dust is produced by cement kilns annu-ally in the United States, resulting in a serious waste disposal problem. The Bureau of Mines investigated two alkali volatilization methods for converting this dust into materials for making portland cement and a useful potassium product. Portland cement kiln dust was found to be composed of finely ground cement raw materials (CaC03 and 8i02) having a layer of alkali sulfate (K2S04 and Na2S04). In this form, it cannot be directly recycled to cement kilns because concrete is weakened by a reaction between the alkali and the aggregate. Portland cements with 28-day strengths above 5,000 psi were produced from low-alkali residues using sintering and melting methods. For nearly complete removal of alkalies, primarily potassium sulfate, from cement kiln dust, a temperature above 1,300° C and a reducing atmosphere were required.

Jan 1, 1986

By Martin H. Stanczyk

The Bureau of Mines studied continuous closed-circuit attrition grinding of a coarse commercial filler-grade kaolin to produce paper-coating-grade clay having a particle size analysis of at least 70 percent minus 2-micron equivalent spherical diameter (esd). The coarse clay, containing about 12 percent minus 2-micron-esd material, was ground in a Bureau-developed 10-inch-diameter attrition grinder in closed circuit with a 5-foot-diameter bowl classifier. In the best test, a finished product containing 82.7 percent minus 2-micron-esd material was obtained when grinding 20 pounds of raw clay per hour at percent solids with a 100-percent circulating load. Energy consumption was about 341 kilowatt-hours per ton of clay feed, or 487 kilowatt-hours per ton of minus 2-micron-esd material produced. Closed-circuit grinding gave some-what greater particle size reduction and lower energy consumption than either batch or continuous open-circuit grinding.

Jan 1, 1965

By Frank D. Lamb, Lloyg H. Baning

"The crushed-stone industry has long been troubled with the problem of producing a more or less cubical product for use as concrete aggregate. Its seriousness varies widely for each producer, depending upon the character of the rock employed for raw material and the ultimate use of the crushed stone. For many construction uses, such as the macadam or bituminous-concrete- type road, flat pieces are not objectionable and may even be preferable to more cubical rock. However, most specifications for concrete require that the stone must be reasonably free from flat and elongated pieces.The rigid specifications set by many contractors have resulted in the rejection of coarse aggregate that, except for the presence of an excessive amount of flat and elongated pieces, would be entirely acceptable. In many instances, if an efficient, economical method of removing flat and elongated pieces were available, local producers could meet the requirements of the contractor and thus eliminate the necessity for importing more cubical material.A brief investigation of the problem of removal of flat and elongated pieces from crushed aggregate, carried out at the Eastern Experiment Station of the Bureau of Mines, indicated that it is mechanically possible to remove flat pieces from crushed rock.TEST EQUIPMENTA number of mechanical devices are used by the coal industry for separating slate from coal; these depend upon the difference in shape of the crushed slate as compared with the coal. Such devices as shutter screens, spiral separators, and the Norman picker would be suitable for removing flat pieces from crushed rock in the same manner as they are used by the coal industry. None of these devices was immediately available for testing purposes, so an attempt was made to construct a simple device that could be used in commercial operations."

Sep 1, 1944