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By G. L. Fitzpatrick

Future applications of seismic holography to "seismically transparent phase objects," such as rock inclusions, fracture zones, liquid-filled cavities, etc., will require techniques to improve the poor image contrast generally characteristic of these objects. Although conventional phase-contrast enhancement techniques could be used, these methods involve additional optical elements such as quarter-wave spatial filters. Owing to the anticipated practical difficulties of properly alining such optical devices and properly locating poorly defined image planes and filter planes, this approach is not considered to be well-suited to the case of seismic holograms and their laser reconstructions. Results similar to those achieved with spatial filters may be obtained without filters by specially processing the seismic hologram data. The new process, which is an extension of Gabor's subtraction holography, achieves an improvement in contrast by an interferometric technique. The process involves adding a ?before" hologram without an object present to a 90° phase-shifted "after" hologram with the object present. Then, the combination is reconstructed with a laser or by computer. Not only is the image contrast improved in such processed holograms, but the images are also phase-contoured. In general, the latter feature is not to be expected when conventional phase-contrast enhancement techniques are employed. The new technique is experimentally verified by examining computer-generated synthetic seismic holograms rather than by examining actual seismic field data. However, results of this study are directly applicable to real seismic data and should prove useful in future applications of seismic holography.

Jan 1, 1973

By Hal J. Kelly

A picture of the ceramic industrial potential of the Pacific Northwest States is presented by reviewing the present ceramic industries, raw-material resources, and current market demands. A resume is given of the industrial plants manufacturing ceramic ware as well as available information on raw-material resources. No attempt was made to prospect for new deposits but rather to evaluate, insofar as possible, those already known. Since much of the industry is concentrated on the Pacific coast, most of the information available on resources concerns deposits in that area. Large, undeveloped districts in Montana and Idaho, however, offer promise of larger reserves of ceramic raw materials. Average annual production, some operating costs, and annual power consumption are given for each of the plants. Production and some cost figures are listed to show the limited nature of the present industry and to suggest fields open for new development.

Jan 1, 1956

By Richard H. Spencer

Since the passage of the Coal Mine Health and Safety Act of 1969, the Bureau of Mines has made many advances in mine communications. These efforts have resulted in the following developments and demonstrations: Surface-to-surface electromagnetic transmission of baseband voice signals through overburdens as deep as 600 feet. This transmission was achieved with equipment from the Interim Mine Rescue and Survival System Program, and demonstrated that baseband voice communications could be obtained through these overburdens in the absence of mine-generated noise; that is, when the mine power system was shut off, However, during mine operational conditions, the mine-generated noise proved to be so large that effective baseband voice communications to the desired depths could not be effected.

Jan 1, 1975

By A. M. Stubbs

The Bureau of Mines has devised a procedure to selectively extract and recover chromic oxide (Cr203) from waste high-temperature shift catalysts that contain approximately 6 pct Cr and 62 pct Fe, both in oxide form. The Bureau's procedure consists of roasting the waste catalyst with sodium hydroxide (NaOH) or sodium carbonate (Na2C03) followed by water leaching. The chromium from the leach liquor was recovered utilizing an oxidation-reduction reaction with pH adjustment to form a hydrous chromic oxide (Crp3oXHp) precipitate. The roast-leach procedure produced chromium extractions greater than 89.7 pct, with product recovery in excess of 99 pct from the leach liquor. The costs of the NaOH and Na2C03 roast processes, including sizing and equipment-related recommendations, were determined by the Bureau's Office of Process Evaluation. The economic evaluation indicates that producing a Crp3 product, at the present time, is not competitive with the present-day cost of imported chromites. The estimated average operating cost for both processes was $5.44/1b of recovered Cr203 concentrate. However, this procedure offers a potential alternative to the disposal of this waste through landfiIl.

Jan 1, 1988

By Robert W. Freedman

This report describes sampling and analytical procedures used for measurement of sulfates in diesel tailpipes and in the diluted exhaust within dilution tunnels. A variety of methods exist for sulfate analysis for such systems, including ion exchange. Two chemical methods used by the Bureau of Mines are described in detail. These are based upon spectrophotometric measurement of chloranilic acid using barium chloranilate. The procedures are rapid and relatively inexpensive. In general, ion exchange is preferred by many analysts for sulfate analysis. However, it is more complex and expensive than chloranilic acid procedures, which are adequate for exhaust analysis.

Jan 1, 1982

By A. W. Deurbrouck

This report presents the results of a washability study of 322 coal mine samples showing the sulfur forms and distribution in the coals. The samples were collected from mines which were principally utility coal producers. Generally, the data show the total sulfur content of the coals evaluated could be significantly reduced by some combination of stage crushing and specific gravity separation. However, few coals could be upgraded to a final product containing 1 percent or less total sulfur. The complete washability data are presented for each sample processed. A statistical evaluation is included for the coalbeds from which more than 10 samples were collected and for the geographical coal producing regions. A graphical summation is presented for the coal producing regions and selected coalbeds.

Jan 1, 1972

By R. Ward Stahl

Fire has been one of man's most useful tools through the ages and certainly is a "must" for industrial progress but when uncontrolled is one of the most destructive agencies. This fact is even more important in a coal mine, where many persons and much expensive equipment are confined in a relatively small area. Means of escape from a burning area, as well as from the products of combustion, are often limited; and in many instances the entire surroundings are combustible. Numerous mine fires, which resulted in a high death toll and great financial loss through the years, have caused mine owners to search for the best fire-fighting equipment; much of this has been installed, the quantity depending largely upon the experience of the individual companies or neighboring mines in certain coalfields. A mine owner or operator has meager published information on the actual fire protection afforded and systems of fire-fighting inaugurated in the coalfields, by which he could compare his efforts and get some idea of the adequacy of his own protection. To further general knowledge of the subject, it was decided to survey a representative number of mines in the field and show what has been accomplished. Representative mines were selected in various coal beds; some had similar tonnage, so comparison could be made if desired.

Jan 1, 1957

By L. C. IlsLey

In January, 1922, a conference relative to trailing cables for use with permissible mining machines was held at the Pittsburgh Experiment Station of the U. S. Bureau of Mines. At this conference it was recommended that the bureau take steps to investigate the rubber-sheathed type of cables and to bring about the establishment of a list of approved cables. Effective until such time as a complete investigation could be made, the bureau asked the several manufacturers holding approvals for mining machines to recommend cables for use with their machines. In general the cables recommended were tentatively approved. Due to the lack of available personnel, no actual tests of cables were made until mid-1927. Meanwhile a field investigation of trailing cables was made at 20 mines of three coal companies in western Pennsylvania, and samples of cables were obtained from the manufacturers for laboratory tests. Twenty-five samples of the concentric-type cable, representing the product of five manufacturers, were obtained for the tests. These cables were of four sizes, as follows: 3 cables of No. 2 B & S gage, 17 cables of No. 3 B & S gage, 3 cables of No. 4 B & S gage, and 2 cables of No. 6 B & S gage.

Jan 1, 1929

Develop a user-friendly computer program that permits those interested in mine health and safety to access and analyze on a personal computer (PC) employment, production, and accident data for U.S. coal and metal-nonmetal mines. This software is being designed with a major focus on flexibility and case of use. The Mine Accident Decision Support System (MADSS) will be available for distribution in mid-1994. Currently, the U.S. Bureau of Mines (USBM) is seeking volunteers willing to pilot test a preliminary version of the software and to provide suggestions for its improvement. Background Since 1975, the Mine Safety and Health Administration (MSHA) has compiled large data bases of information about U.S. mines and the reportable accidents, injuries, and illnesses that have occurred in those mines. Employment and production data arc collected on a quarterly basis from each mine and accident information is collected on an incident -by-incident basis. The USBM has compiled estimated costs for each of these accidents using computer models. All of this information is potentially useful to mine health and safety researchers. However, it has been underutilized because it is stored in large mainframe data bases that arc inaccessible to many users and/or are cumbersome and difficult to use.

Jan 1, 1993

By Launa G. Mallett, Charles Vaught, Michael J. Brnich

Beginning in 1991, scientists at the Pittsburgh Research Laboratory recorded interviews with individuals who are recognized as experts in mine emergency response. These 30 veterans related stories and observations from events experienced during as many as 47 years of response activities. Overall, the response veterans averaged 29 years of mine emergency response experience and 35 years of mining experience. Interviewees included representatives from mining companies, the United Mine Workers of America, and State and Federal agencies. Most of their comments dealt not so much with technical aspects of particular mine emergency responses, but rather the human side of more general topics, including preparedness, experience, people on-site, mine rescue teams, and decision-making. An analysis of their interviews provides an overview of lessons learned on-site at some of the largest mine disasters since the mid-1940s. This knowledge was gathered so that it could be provided to today's miners and to tomorrow's emergency response personnel. It is expected that the collective wisdom obtained can be used to help train new responders and guide those decisions that will have to be made on the scenes of future events.

Jan 4, 2004

By A. W. Fahrenwald

"Cooperation was arranged between the mine operators, the Michigan College of Mines and Technology, and the Bureau of Mines for a study of present milling practice in the copper district of Michigan. Work was actively commenced in January, 1928.In Michigan copper occurs almost wholly as native copper. An insignificant amount of copper sulphide is present. The native copper occurs in two general classes of formations--namely, amygdalaid and conglomerate.In respect to ore dressing, the outstanding peculiarities of the two types of copper are: (1) In the amygdaloid, the relative coarseness of the metallic copper, which is almost completely liberated at approximately 48-mesh comminution; (2) the sprangly and flakey physical character of much of the liberated copper after crushing; (3) in the conglomerate, the extremely fine dissemination of the metallic copper, which is not completely liberated by crushing to -200 mesh.Because the study to date has been confined almost wholly to amygdaloid ores, the conglomerate class is not considered herein. The conglomerate ore is being efficiently treated, and the loss of copper is small.The amygdaloid ore contains a silicious gangue of which 80 per cent has a specific gravity of less than 2.84, 92 per cent of less than 2.94, and 98 per cent of less than 3.17. Epidote of 3.25 specific gravity is noticeably present, and accumulates on the table concentrators, from which it is hard to make clean con¬centrate and middling recovery.The general nature of the amygdaloid ores varies a little from mine to mine, but the general characteristics are the same, as is shown later by flotation tests."

Jun 1, 1928

By L. A. Neumeier

The Bureau of Mines evaluated the properties and anisotropy in properties of rolled Zn-Ti and Zn-1.0 wt pct Cu-Ti alloys containing up to 0.36 wt pct Ti. Finish rolling was at varied temperatures to total reductions as high as 92 pct. Alloy properties are very sensitive to various combinations of composition, rolling temperature, and reduction. Properly rolled Zn-1.0 Cu-Ti alloys are superior in strength to Zn-Ti alloys. Conditions are described that lead to best tensile properties. Creep resistance for Zn-Ti alloys decreases with increased rolling temperature when finish rolled to 92-pct total reduction: but not when finish rolled to 33- or 67-pct reduction. Creep resistance for 7n-1.0 Cu-Ti alloys improves with increased rolling temperature to about 480° F. Heavily cold-rolled Zn-1.0 Cu-Ti alloys have fine grain sizes and poor hardness, tensile, and creep properties, but high ductility. Thermal expansivity is markedly affected by the copper addition. Data show the anisotropy of tensile, creep, and thermal expansivity properties. Large idiomorphic crystallites of TiZn15 appear in both Zn-Ti and Zn-Cu-Ti alloys when more than about 0.2 pct Ti is present. A new Zn-Cu-Ti intermediate phase was also identified. Empirical equations are presented relating creep rates with major process variables.

Jan 1, 1971

By Ernest F. Burchard, J. R. Thoenen

"INTRODUCTION Technically speaking, bauxite is not a definite mineral but a mixture of several minerals belonging to a group of partly consolidated material known as laterite, which have been formed by surface weathering of rocks.The term bauxite is applied to the ore of aluminum, although a substantial amount is used for other purposes, such as a base in certain chemical industries and in the manufacture of artificial abrasives, refractories, and certain cements. Although bauxite has not been classed as strategic it now appears that the domestic supply may be insufficient for expanded defense requirements.Until recently, domestic production of metallic aluminum has been ample to meet requirements, but estimates of pyramiding future needs of the defense program have caused serious attention to be directed to the self-sufficiency of this country, both as to the supply of the raw material, bauxite, and the metallurgical capacity available to convert the ore to metallic aluminum.At the request of the Secretary of the interior, representatives of the Bureau of Mines and the Geological Survey recently investigated domestic resources of bauxite.A preliminary study of published literature and a field investigation disclosed that"

Nov 1, 1941

By T. E. Purcell

(a) Moisture. - Moisture, "as fired," is specifically significant in pulverized-coal firing because of its effect upon the continuity of raw-coal feed to the pulverizer, pulverizer capacity, flame stability, and speed of ignition. The extraneous moisture content is a rough index of potential difficulties in unloading and maintaining the flow of raw coal to the pulverizer and of pulverized coal to the furnace, with the troubles increasing geometrically as the percentage increases. Sticking or other stoppage of coal flow at any point between the bunker and the furnace is especially serious with pulverized-coal firing because there is danger of immediate loss of output. Where moisture is a problem, the designer must exercise great care in the design of coal-handling and preparation apparatus.

Jan 1, 1951

By Ellis S. Hertzog

The data published in this report cover only one phase of a special study of the physical and chemical properties of Alabama coals made by the Bureau of Mines. In addition to determinations of friability, the survey included determinations of grindability, B.t.u. value, end ash-fusion temperature. Assay distillation tests, both for high- and low-temperature carbonization, and proximate and ultimate analyses were made also. However, this preliminary paper is concerned only with the results of friability tests and is issued to expedite the release of this information to the public. The friability test measures the liability of a coal to break into smaller pieces when subjected to repeated handling, as occurs in the mining, preparation, and transportation operations. Friability depends on many physical characteristics of the coal that vary not only between different seams but also in the same seam. The laboratory methods of determining friability have been developed to give a practical means of estimating degradation of size. So far as is known to the authors, no data on the friability of Alabama coals have ever been published. This paper makes available for the first tine fairly comprehensive information on this subject. Because the procedure for the tumbler test for determining the friability of coal is relatively new to the coal operators, the authors have included a complete description of it in this report.

Jan 1, 1938

By (NIOSH) Publication

In 2004, a total of 2,011 coal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Coal mines comprised 13.9% of all mining operations.

Sep 1, 2007

By Milton B. Hall

This report discusses in detail laboratory and pilot-plant tests conducted from January 1951 until January 1955 at the Northwest Electrodevelopment Experiment Station of the Bureau of Mines, Albany, Oreg., on defluorination and recovery of evolved fluorine from phosphate rock. Results of use tests of defluorinated phosphate rock by cooperating agricultural colleges and the United States Department of Agriculture are also included. In 1954 the consumption of fluorspar, the only domestic fluorine-bearing mineral of commercial importance, was approximately 478,000 short tons; 245,000 tons was from domestic mines. The production of marketable phosphate rock in the same period was about 13,800,000 long tons. Of this total amount, approximately 15 percent was produced in the West. From the viewpoint of conservation and utilization of fluorine as a natural resource, it is interesting to note that the total estimated quantity of fluorine in domestically produced phosphate rock is more than double that present in domestically mined fluorspar.

Jan 1, 1958

By H. N. Smith

IN 1944 the Congress passed the Synthetic Liquid Fuels Act that authorized the Secretary of the Interior, acting through the Federal Bureau of Mines, to conduct basic research and construct and operate demonstration plants to produce synthetic liquid fuels from coal, oil shale, and other substances. As a basis for the oil shale investigations to be undertaken in this country, the progress of foreign countries in developing and using oil shale as a source of liquid fuels was studied by the technical missions of the Federal Bureau of Mines. Oil shale mines, retorting plants, and refineries were visited; geological information on the nature and occurrence of the foreign oil shales was obtained; and samples of the oil shales were collected where possible. Samples collected by these missions or acquired by other means came from Australia, Brazil, Canada, France, Manchuria (China) , New Zealand, Scot-land, Spain, Sweden, Thailand, and Union of South Africa. These countries represent a large part of the locations where oil shale developments have taken place. The major omissions are the Estonian, German, and Russian developments.

Jan 1, 1959

By Paul R. Coyle, Anthony T. Iannacchione

A close look at the Loyalhanna Limestone of southwestern Pennsylvania reveals a complex structural environment. Most exposures of the Loyalhanna occur along Chestnut Ridge and LaurelHill within the Allegheny Mountain Section of the Appalachian Plateaus Province. Because the Loyalhanna is rated as a super-pavement aggregate by the Pennsylvania Department of Transportation and because of its proximity to the population centers of southwestern Pennsylvania, the Loyalhanna has been extensively mined along these prominent anticlinal structures. Geologic and engineering analyses were performed using gas well and core logs, outcrop examinations, underground observations, and mine maps. Strata exposures from both outcrops and quarries were used to construct geologic maps, stereo net, and rose diagram projections so that the Loyalhanna’s structural environment could be understood better. Many of these structural conditions cause ground control problems at local quarries. These problems ranged from small-to-moderate sized rock falls associated with roof jointing to pillar failures associated with dipping discontinuities. Stresses ranged from tensional on structural domes where weathering dominates, to high levels of compression within structural saddles. A greater understanding of these characteristics is a prerequisite to develop engineering controls, such as improved mine layouts, pillar sizes, etc., that lessen miner exposure to these hazards.

By Terry J. Close

The highly-mineralized 43,700-ha Rapid River study area, on the southeast side of Hells Canyon Wilderness and west of the village of Cuprum, in Adams County, western-Idaho, was investigated in 1992 by the USBM (U.S. Bureau of Mines) in conjunction with its Idaho Land Assessment Program. The 1992 study updated data gathered during the USBM's 1974-76 Wilderness investigation. The studies consisted of the evaluation of 61 mineralized sites and the estimations of tonnages, grades, and minability of these sites. Most of the sites studied are in two mineralized locales--Windy Ridge and Jackley Mountain. A few isolated sites, peripheral to the two locales, were also examined. The 61 sites contained more than 340 mine and prospect workings, including about 10,300 meters (34,000 feet) of underground workings, plus 134 drill holes.

Jan 1, 1993