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By Clarence Karr

THE BUREAU OF MINES is investigating methods for upgrading tar produced by the low-temperature carbonization of bituminous coal. This survey was undertaken to compile information needed for identifying the ether constituents of low-temperature tar. Physical properties are listed for 1,024 aromatic ethers. The compounds include cyclic and noncyclic, polyfunctional and monofunctional ethers with oxygen joined directly to either one or two aromatic rings. Alkyl groups up through butyl are included. The compounds are divided into 37 groups ranging in complexity from alkoxybenzenes to dibenzopyrans. Compounds containing aromatic ether groups are important constituents of the neutral oxygen components of low-temperature tar. For example, at Morgantown, W. Va., the Bureau of Mines has identified and determined the amounts of benzofuran, 2-, 3-, 5-, 6-, and 7 -methylbenzofuran, diphenyl ether, dibenzofuran, 2,3-dimethyldibenzofuran, and two other dimethyl-dibenzofurans in the neutral oil from a low-temperature bituminous coal tar (103, 104).3

Jan 1, 1962

By Charles W. Huggins

A study of the high magnification of some inorganic fibers which are found in nature or produced in the laboratory, has been conducted with the electron microscope. This series of electron microqraphs shows the important morphological differences exhibited by potassium-lead silicate, lead-aluminum silicate, chrysotile, wollastonite, silicon nitride, potassium titanate, cobalt chrysotile, magnesio-fluor-richterite, fluor-richterite, refractory oxide fiber, silicon carbide, massive serpentine, and palygorskite. A ribbon or a thin lath 250-2500 A. wide is the structural form of potassium-lead silicate and lead-aluminum silicate. Chrysotile, cobalt chrysotile, and massive serpentine all have a tubular structure and a fairly uniform (150-300 A.) diameter. Wollastonite, potassium titanate, fluor-richterite, and magnesio-richterite crystals have a lath shape, and potassium titanate laths are laminated ribbons. Single fibers of silicon nitride and palygorskite are ribbons, and the silicon nitride sample contains many twins (branching fibers). Palyqorskite fibers are highly flexible and have cross-sectional measurements of 150-300 A. Silicon carbide fibers differ from other fibers because their structure consists of several different forms. The sample used in this study had, predominately, a margarite-type structure. The refractory oxide fiber lost, all its apparent fibrosity after being prepared for electron microscopic examination, and only irregular fragments are visible in the electron micrographs.

Jan 1, 1962

By E. H. Izen

A thermal imaging borehole probe was designed and fabricated for the purpose of obtaining thermal images, through smoke, of objects and people in underground mines. The effort was basically unsuccessful; electrical noise, and possibly thermal noise, interferred with the desired signals to the extent that spatial resolution in the images was unacceptable.

Jan 1, 1980

By J. R. Thoenen

[For several years the Bureau of Mines has conducted tests on ground vibration emanating from quarry blasting in an effort to determine Fin index of destruction for different types of structures. Results of these studies have been published in four Bureau of Mines Reports of Investigations as well as in several articles in the trade and technical press.5/ The first paper (3)6/ discussed the subject in general and gave results s of a few blasting records. Some tentative theories also were advanced. The second paper (4) discussed results s of records made from blasting in a number of quarries.]

Jan 1, 1940

By T. M. Barczak

This U.S. Bureau of Mines report investigates shield mechanics and component stress development in a two-legged longwall shield for unsymmetric canopy and base contact configurations. Previous studies analyzed shield behavior for symmetric contact configurations. The goals of these efforts are to improve longwall support selection and design. This study provides vital information that will help develop improved procedures for performance testing of longwall supports and will benefit future research to improve support design through stress optimization and evaluation of failure mechanisms. Combinations of six canopy (three symmetric and three unsymmetric) and six base (four symmetric and two unsymmetric) contacts provided a total of 36 configurations for evaluation. Of these 36 configurations, 10 were eliminated because of fixture limitations or shield instability. Controlled vertical and horizontal displacements were applied by the Bureau's mine roof simulator to the remaining 26 configurations. Component responses were determined from pressure transducer and strain gage instrumentation in order to identify contact configurations and boundary displacements that produced maximum loading in each of the support components. This report describes these test results and provides conclusions relevant to critical contact configurations for performance testing of longwall supports.

Jan 1, 1990

By J. R. Thoenen

[For several years the Bureau of Mines conducted tests on ground vibration t emanating from quarry blasting in an effort to determine an index of destruction for different types of structures. Results of these studies have been published in four Bureau of Mines Reports of Invitations as well as in several articles in the trade and technical press.5/ The first paper (3)6/ discussed the subject in general and gave results s of a few blasting records. Some tentative theories also were advanced. The second paper (4) discussed results s of records made from blasting in a number of quarries.]

Jan 1, 1940

By Paul M. Ambrose

Overall the domestic abrasives industry had one of its best years in 1965. Production and value of all commodities increased over that of 1964 which also was a good year. Production of tripoli that was down in the previous year rebounded and production from two new mines was reported. Plant capacities for production of silicon carbide and fused crude aluminum oxide and production from plants in the United States and Canada increased, but demand was high and yearend stocks were less than at the end of 1964. Foreign Trade.-Increases in value of most imports of abrasive materials in 1965 were offset by a decrease in the value of imported industrial diamond. Production of fused aluminum oxide and silicon car-bide in the United States and Canada and imports of these commodities into the United States increased, but combined exports of finished grain of these materials was virtually unchanged from the previous year.

Jan 1, 1966

By D. A. Reynolds

THIS REPORT gives results of an investigation of the carbonizing properties of two Tennessee coals, one from the Jellico bed in Campbell County and the other from the Sewanee bed in Marion County. Jellico coal and blends with 20 and 30 percent Pocahontas No. 3 coal were carbonized at 800° and 900° C. by the BM-AGA method. Sewanee coal was carbonized by the same method at 800°, 900°, and 1,000° C.; blends with coals of similar and different ranks were carbonized at 800° and 900° C. The coals were subjected to various physical and chemical tests, including complete chemical analyses, low-temperature assays, and agglutinating, free-swelling, friability, plasticity, and expansion tests. The Tennessee coal field is a part of the Appalachian field, which extends from northern Pennsylvania to central Alabama. The Jelico bed, one of the most important in the State, is part of the Jellico formation, which is above the Lee formation of the Lower Pottsville. Sewanee coal bed belongs to the Sewanee conglomerate and is stratigraphically lower than the Jellico bed.

Jan 1, 1953

By V. F. Parry

This report is the first substantial description of the carbonizing process and the details of experimental work conducted at the Denver laboratories under a coopeative agreement between the Bureau of Mines and the Texas Power & Light Co. It presents the results of tests on several Texas lignites and other typical western coals that have been processed in the first pilot plant operated at Denver. Investigations on drying fine coal in the entrained and fluidized state have been under way at Bureau of Mines Denver laboratories for several years. Reports on this work were published in 1949 and 19505/ describing the theory and practice of re-moving inherent moisture from the lower -rank coals. The investigation did not include a study of the removal of surface moisture from fine fuel. Private industry in Canada became interested in the possibilities of drying fine coal, employing the closed-circuit system and techniques recommended by the Bureau. Large, commercial-scale drying units were built by a Canadian company, which successfully demonstrated that surface moisture could be removed from fine coal at high efficiency and capacity ill drying units similar in design to those developed by the Bureau.

Jan 1, 1953

By Michael Rieber

Commodity transportation by barge is possible on about 25,000 miles of navigable inland waterways in the contiguous 48 states. Barge operations are used chiefly for the movement of bulk raw materials ranging from farm products to iron ore, coal, and other bulky semi-finished as well as finished products such as steel, chemicals and petroleum [3,p.7-9]. The barge industry, unlike other transportation industries, is largely unregulated. This is because all liquid bulk commodities most dry bulk commodities transported by for-hire carriers and companies engaged in private transportation of their own commodities are exempted from Interstate Commerce Commission regulations. As a result, about 15 percent of the total ton-miles of barge traffic each year is under Interstate Commerce Commission regulation [13,p.14-25].

Jan 1, 1977

By Walter W. Kaufman

This report summarizes a study conducted to establish the nature and impact of regulations governing disposal of refuse from underground coal mines. The regulations affecting refuse disposal in eight major coal producing states are collected, summarized and reviewed. Federal regulations applicable to refuse generated by underground coal mines are also included. Common refuse disposal practices are discussed as are the refuse quantities generated annually in each study state. Technical requirements of regulations are discussed acid presented in appended tables. Economic implications are also assessed through cost analyses of three major types of disposal processes. The report also includes an assessment of future trends in regulation and refuse generation plus a series of recommendations concerning potential improvements in both the regulatory and refuse disposal processes.

Jan 1, 1978

The first metal-mine accident-prevention course was prepared and published 1942-45 as a series of seven miners' circulars (Nos. 51-57). The course has been broadened, revised, and brought up to date and is being published as a similar series of seven miners' circulars on accident prevention at metal and nonmetallic mines. These circulars are: 1. Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

By Walter C. Woodmansee

The only reported mineral production in 1977 was small output of alluvial gold, valued at an estimated $54,320.2 In addition, marine shells are gathered for use in lime manufacture, although output was not reported. Proposed development of a bauxite mine and smelter, involving Rennell and Vaghena Islands, was deferred in June. Conzinc Riotinto of Australia Ltd. (CRA), in partnership with Mitsui Mining & Smelting Co. Ltd., and the Solomon Government, with- drew from the project, and Mitsui, which conducted a feasibility study and metallurgical testing of the bauxite, decided to defer further work because of slack demand for aluminum in Japan and difficulties in arranging financing. The Mitsui feasibility studies reportedly indicated that the project could be viable despite technical difficulties and relatively high initial investment costs. The project was to produce 1.5 million tons of bauxite and 600,000 tons of alumina per year from reserves totaling 60 million tans at 45% to 50% A1203.

Jan 1, 1981

By Forrest T. Moyer

Injury experience at metal mines and mills (excluding officeworkers) in 1964 was 60 fatal and 3,672 nonfatal disabling work injuries during an exposure time of 149 million man-hours worked. These injuries occurred at a frequency rate of 24.57 per million man-hours and had a severity rate of 3,687 days lost or charged per million man-hours. Employment at 2,363 metal mines and 291 mills, excluding officeworkers, was 68,140 men in 1964. The average number of days worked was 274 The principal cause of fatal injuries at all mines and mills was haulage accidents and in underground mines, only, was falls of ground. The principal cause of nonfatal injuries was handling material accidents. The frequency rate at metal mines and mills in 1964 was slightly below that of 1963, whereas the severity rate was higher. Injury experience at 94 primary nonferrous smelters, refineries, and reduction plants (excluding officeworkers) was 8 fatal and 999 nonfatal disabling work injuries during a worktime of 98 million man-hours worked. The combined injury-frequency rate in 1964 was 10.29 and the injury-severity rate was 1,005. The 36,956 employees worked an average of 329 days during 1964. The principal cause of injuries at these plants was handling material accidents.

Jan 1, 1968

By Terry J. Close

From 1981-84, Bureau of Mines personnel examined and evaluated mines and prospects in the highly mineralized 62,400 acre Inyo Mountains U. S. Bureau of Land Management (BLM) Wilderness Study Area (WSA), located east of Lone Pine, CA. The 62,400 acres studied is the part of the 87,145 acre WSA designated as suitable prior to February 28, 1983. The WSA is underlain principally by quartz monzonite and quartz diorite that have intruded sedimentary and volcanic rocks. Three types of mineral deposits are present: 1) gold in fissure veins, 2) silver in fissure and replacement veins, and 3) talc in metasomatic lenses. Of the 84 nines, mills, and prospects examined, 54 are significant: 1) 5 in the intrusive rocks total about 4.4 million tons of inferred marginal gold reserves averaging 0.24 oz gold and 0.74 oz silver/ton; 2) three associated with intrusive-sedimentary rock contact zones total about 280,000 tons of inferred subeconomic silver resources averaging 7 oz silver/ton; 3) 27 gold and silver occurrences in the intrusive and sedimentary rocks total about 1.2 million tons of material in poorly defined bodies too small or low grade to be resources; 4) 15 gold and silver occurrences in the intrusive and sedimentary rocks are too poorly exposed to estimate tonnage and grade; and 5) four talc deposits along intrusive-sedimentary contact zones have inferred marginal reserves totaling about 640,000 tons. The marginal gold reserves at $450/oz might be profitably mined (reserve) at a gold price of about $600/oz and the subeconomic silver resources at a silver price in excess of about $27/oz. The marginal talc reserves might become minable at prices of about $50/ton and $80/ton for unprocessed and processed talc, respectively, after present supply sources are depleted. At most of the 54 significant mines and prospects, additional reserves or resources would likely be disclosed by trenching or drilling. Present in the WSA are 13 gold mills, numerous small pits and cuts, 270 underground workings totaling about 36,000 ft, and 80 mining benches totaling about 11,000 ft. Gold, silver, or talc were produced from most of the workings. A total of 1,561 lode and 18 placer samples were taken.

Jan 1, 1985

By Rudolf E. Greuer

Every mine contains inflammable materials, either in form of the minerals mined or in the form of brought-in supplies. Although great efforts are made to make mines as far as possible fireproof and to prevent ignition sources, the possibility of mine fires, like that of other accidents, will always continue to exist. Detailed statistics are available for coal mines. They show (65,112) that the number of major mine fires in the USA over the last 20 years has remained more or less constant with approximately 50 per year. The same number is reported (26) for the British coal mines. Other countries (147) report about 1 major fire for every 10 million tons of coal production. Conflicting data are published on the number of fatalities caused by fires, presumably because frequently deviating opinions on the cause of death exist. On the average (82,99) 4 miners are killed per year in the US and in the British coal mines. Although this number is much smaller than that for several other causes of fatalities, one must keep in mind that almost every small fire can develop into a large disaster.

Jan 1, 1973

By S. B. Christy

This report on the electrodeposition of gold and silver from cyanide solutions represents work that has occupied my time at intervals during the past 20 years. The investigation has been carried on simultaneously with my duties as professor of mining and metallurgy of the University of California. During shis long investigation I have been assisted in the details of the work by, a number of my former students, acting in turn as assistants. Particular mention in this connection is due W. H. Hilton, who graduated in 1900; C. T. Dozier, 1902; N. C. Stines, 1905; H. N. Herrick, 1907, and L. C. Uren, 1911. It is impossible to publish full details of the many thousands of experiments performed. Effort has been made to present only the essential data. Wherever possible, the results of the experiments have been expressed in diagrammatic form by curves showing the relation between the simultaneous variables of the experiments. It is necessary to show, as nearly as may be, the state of the art. This is difficult because of the meager literature on electrodeposition in the cyanide process; hence resort must be had to the specifications and claims of patents, most of which seem never to have been applied on a working scale. Such information consequently can not be taken at its face value. Expressing the essential ideas evolved in such specifications is no easy task. Clearly, in quoting from patent records it is not ·feasible to enumerate all of the specifications or the claims allowed the inventors. A statement of the chief contributions to the art in the patent cited must suffice. Legal details, of course, must be obtained from the original patent. In the study of patent literature, when one compares the ardent hopes of the inventors with the results realized from their efforts, it becomes clear that in the development of an art no one man contributes everything. Each subsequent inventor stands on the shoulders of the one who has gone before. It is only through the summation of the contributions of many inventors that the art as a whole prospers. On October 19, 1887, a British patent was granted to McArthur and Forrest for the use of dilute cyanide solutions for treating gold and silver ores. The rapid extension of this process, in various forms, all over the world, has almost revolutionized the treatment of ores containing precious metals. It is a remarkable fact, however, that long before this patent was granted there was issued, on February 5, 1867, to J. H. Rae, U. S. patent 61866, for an electrocyanide process. Thus a method of electrodeposition from cyanide solutions used for treating ores was invented 20 years before the McArthur and Forrest patent .was granted, although the process did not come into general use. On May 24, 1889, U. S. patent 403202 was granted to McArthur and Forrest for the use of zinc shavings for removing gold and silver from cyanide solutions. The use of finely divided zinc is still the standard method for recovering 'gold and silver from cyanide solutions. Since this patent was granted, many attempts have been made to replace the precipitation upon the zinc by methods of electrodeposition. It is the purpose of this report to give an outline of some of these methods, as well as to show the relative advantages and disadvantages of the zinc and the electrical methods of recovering gold and silver from cyanide solutions.

Jan 1, 1919

By J. M. WADSWORTH

The purpose of this bulletin is to describe the methods of constructing and operating representative types of plants in the United States used for removing the light hydrocarbons from petroleum by continuous distillation, such plants being commonly known in the trade as topping or skimming plants. In the discussion of each plant an endeavor has been made to arrange the text similarly in order to facilitate comparison and to emphasize the important features. The various experimental values for the specific and the latent heats of the oils apply approximately to the oil treated. Careful experiments with each oil and its commercial fractions were not justifiable in view of the purpose of this report. It is regretted that limitations for recording data at the different plants made impossible the determination of a heat balance for each, which would have provided an equitable method of comparing efficiencies. The writer has confined himself to a comparison of the relative efficiencies of the distilling apparatus alone by the following method: Effi . f till d tt" _ Heat theoretically required. ciency 0 SIS an se mgs - Heat content of fuel consumed. The plants described are all in California where the topping industry has had its growth accentuated by the character and the use of the oil handled. The scarcity of suitable coal made the adoption of other fuel necessary, and the heavy oil of California supplied the need. To raise the flash point and to dehydrate this oil, various plants have been developed. However, the topping industry is represented in other fields; the Roxana Petroleum Co. of Cushing, Okla., and the Warner-Quinlan Asphalt Co. of New Jersey, are operating Trumble plants, and Texas and Oklahoma operators have been experimenting with different pipe retorts for continuous running. In addition to the reasons for topping cited above, in California topping has other purposes which give the plants practically a universal field in the oil industry. These additional purposes are (1) to remove the lighter constituents of the oil prior to storage for a long period, thus reducing the losses from evaporation, (2) to dehydrate and clean the oil, and (3) in conjunction with a complete refinery, to remove the lighter fractions cheaply and quickly, leaving a residue to be rerun for lubricants, coke, and other products. The reader in studying a plant for possible adaption to his own use should note that local considerations enter into the design and size of a plant. Several questions present themselves, as follows: 1. What type is suitable for the oil? 2. How much money is available for construction? 3. Will the volume of residuum be large enough for heat exchange with the crude? 4. Can the heat content of the vapors be used to reduce the cooling-water requirements? 5. What method will best recover the heat from stack gases? 6. Are the various pieces of apparatus adequate in size and best adapted to their purpose? 7. Is every possible provision made for the recovery of waste heat? 8. What products will be made, and what volume of each? 9. Is there provision for the recovery of light vapors? 10. Will the saving of fuel justify the capital and maintenance charges on the regenerative apparatus contemplated? It is regretted that information concerning the operation of topping plants with eastern and Middle West oils is not available. The writer carefully canvassed the Middle West, but did not find a plant where operation had progressed beyond the early experimental stages and reliable figures could be furnished. The reader will find fuel economy and heat recovery emphasized throughout the descriptions. The conservation of the available petroleum supply is of the utmost importance, and the Bureau of Mines presents this paper to encourage the hearty cooperation of operators to that end. The Baume gravity scale used throughout the report is that of Tagliabue with a modulus of 141.5 for conversion to specific gravity.

Jan 1, 1919

By F. J. Wiebel

"INTRODUCTION As a result of a general survey of the iron-ore deposits of Califor¬nia, the Bessemer was one shown to offer possibilities of developing com¬mercial ore reserves. Surveying and exploring were done at the request of Congress for an investigation of raw materials for the production of steel.A wartime steel plant has been established at Fontana, San Bernardino County, and a backlog of iron-ore reserve for the maintenance of permanent steel industry on the West Coast will be of National benefit in the postwar period.W. D. McMillan, a mining engineer the Bureau of Mines, examined the property in May 1942, and it was reexamined by D. W. Butner, also of the Bureau, in October 1943. Geophysical work was done by the Bureau in 1944, and the property was explored by diamond drilling from April to August 1944 and February to SeptemberACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, under the direction of Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, under the direction of R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

May 1, 1947

By Levent Ozdemir

A 6-ft. diameter laboratory tunnel, raise and shaft boring machine was designed and constructed to carry out research investigations to enhance the performance of mechanical rock excavation equipment. The machine is operated with a computer control system and features extensive instrumentation to monitor and record various test parameters, including tri-axial cutter forces, machine thrust, torque, rpm and penetration rate. An extensive laboratory testing Program has been conducted using this machine, demonstrating the feasibility of attaining high rates of penetration in various sedimentary geologies. Also, a large data base has been developed to serve as a basis for the improved design and performance of tunnel, raise and shaft boring equipment.

Jan 1, 1986