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By George T. Faust

The petrographer engaged in examining the products resulting from the beneficiation of ores and rock minerals is constantly required to develop new means and methods of assaying microscopically the results of such operations. From time to time investigators have published descriptions of apparatus that have aided in solving problems in processes f physical separation. Thus, in 191.9, Coghill and Bonardi 31 published a paper covering the application of the binocular microscope and camera lucida to the microscopic analysis of pulverized ores. Similar work has been published by Schneiderhohn 4/, Schwartz 5/, and Head and his associates6/, 7/, 8/. The present paper goes further and considers application of the polarizing comparison-microscope to problems directly concerned with mineral dressing where it is desirable to compare analogous products, and in addition it suggests new uses in various related fields. This work was conducted under the cooperative agreements of the Southern Experiment Station of the Federal Bureau of Mines and. the University of Alabama.

Jan 1, 1940

By Ronald T. Mayerle

In 1986, at the request of the U.S. Bureau of Land Management, the U.S. Bureau of Mines studied a 20,500-acre part of the 104,085-acre Rincon Wilderness Study Area (OR-002-082) in order to evaluate its identified mineral resources. The wilderness study area is located in Harney County, OR, about 12 miles west from Fields. No mineral resources were identified within the study area. A literature search found no records of mining or minerals exploration, nor did a ground search find any evidence of mining-related activity. Of seven alluvial samples taken from the major drainages of the study area, all were barren except one. This sample, taken from a dry streambed along the southern boundary, contained $0.07 gold per cubic yard; however, this small amount of gold is of no economic significance, and the source is probably outside the study area. The Pueblo-Steens mining district extends to within 4 miles east of the study area. No evidence of geological environments similar to those that were responsible for the formation of resources or occurrences of metals and nonmetals within the district is known within the study area.

Jan 1, 1987

By H. J. Heinen

This Bureau of Mines report reviews the recent developments in the heap leaching of gold ores with dilute cyanide solutions and the recovery of gold and associated silver from the pregnant effluents by a carbon adsorption-desorption method. Mineralogical considerations, experimental work, field studies, and commercial operations are described. Also presented are recent process advances developed by the Bureau, including the application of (1) alcohol additives to the conventional hot alkaline cyanide strip solution to enhance gold desorption from precious metal-laden activated carbon, and (2) Na2S precipitation of the silver from geld-silver cyanide solutions as a means of reducing the inventory of carbon required for precious-metal adsorption from heap leach effluents and for the production of low-silver bullion from activated carbon stripping solutions.

Jan 1, 1978

By James A. Wasson

This report summarizes the results and conclusions reached by various investigators who have attempted to determine the extent to which hydraulic fracturing will affect the secondary recovery of crude oil by waterflooding. It also discusses the most advantageous use of this well-stimulation method in waterflood projects. A thorough search of the literature was made, and pertinent information was abstracted from appropriate reports. A carefully designed and controlled program of formation fracturing is an effective aid in waterflooding because it increases water-injection and oil- production rates. Generally, fracturing has resulted in little or no reduction in ultimate oil recovery, but under certain circumstances recovery has been substantially increased.

Jan 1, 1963

By William Seymour, L. D. Schmidt, J. W. Myers, W. T. Reid

"This investigation was conducted by the Bureau of Mines as part of a program of the Solid Fuels Administration to encourage the utilization of anthracite fines, the objective being to determine the practicability of using anthracite fines in the manufacture of packagedThe experimental loss of packaged fuel covered by this report were made at a commercial plant using the Glenn Smith process and ordinarily making packaged fuel from Pocahontas screenings. These lots included several made from straight antimacite mines and others made from various blends of anthracite fines with four different bituminous coals. In all cases an asphalt binder was used. Determinations of the physical properties and the cobustion characteristics o the various samples of packaged fuel were made by the. Bureau of Mines at the Central Experiment Station.The physical tests indicated that a packaged fuel of sufficient strength for ordinary handling can be made from straight anthracite coal or from a wide variety of blends of anthracite fixes with bitunimous coal, using asphaltic binder. However the combustion tests indicated that packaged fuel made from anthracite alone tended to crumble excessively during burning and that as much as 30 to 50 percent of a caking coal may be required In the mixture to produce a block having satisfactory combustion characteristics.The authors wish to acknowledge the. splendid cooperation of Messrs. H. W. Kelly, J. L. Mooney and C. H. Stoss of Columbus, Ohio, who were chiefly responsible for obtaining the materials and making all the arrangements necessary for the production of the packaged fuel for testing.Thanks are due to the officials of Carnegie Institute of Technology for the use of their Olsen. Testing Machine and to H. M. Cooper and W. A. Selvig of the Bureau of Mines for analyses and tests."

May 1, 1946

By C. B. Davison

One goal of the Bureau of Mines is to conserve the Nation's mineral resources by developing improved performance materials. Consistent with this goal, the Bureau conducted studies on the formation of undesirable cristobalite in seven different fire clays used as refractories. The studies employed scanning electron micrography, chemical and X-ray analyses, and pyrometric cone equivalent determinations to examine the sample clays and determine the effect of thermal history and stablilizing additives on the amount of cristobalite in various calcines. This research has indicated that as fire clay calcining temperatures increased from 1390° to 1,490° C there was a gradual decrease in the percent of cristobalite present in the calcines and a progressive development of mullite crystallization. No cristobalite was found in fire clays calcined above 1,550° C, but cristobalite reappeared when the calcines were reheated to temperatures between 1,400° and 1,500° C. The research also revealed that additions of lithium fluoride (LiF) prevented formation of cristobalite in fire clay calcines.

Jan 1, 1979

By A. M. Cummings

Each mining district presents different problems as to the methods of ore extraction cad underground support, which are dependent upon the type of the ore deposit and the character of the inclosing rock. Mining costs, however, depend largely aeon the efficiency with which the methods employed underground are [applie] as well as upon the selection of the method best adapted to the physical conditions. The purpose of this paper is to present to the operator in other districts a detailed description of ho mining method used ins results obtained in tie exploitation of the bedded magnetite deposits of the Mineville district. The town of Mineville is situated in the Adirondacks, five miles west of Port Henry on Lake Champlain.

Jan 1, 1928

By Victor R. Spironello

Applications of three experimental design techniques to smelting operations are explained. The report describes a factorial design using three variables at two levels, a fractional factorial design which investigates seven variables, and response-surface methodology for optimization of electric- furnace smelting processes. These methods may be applied with a minimum of trials and at little expense. Further, the writer knows of no reasons why the same methods could not be applied to other operations as well, such as steelmaking.

Jan 1, 1970

By Derek Ellis

Volume II of this two-part series on Submarine Tailings Disposal (STD) as a tailings management option for coastal and island mines contains descriptions of lesser known case histories. The Misima gold mine (Papua New Guinea) and the Black Angel lead-zinc mine (Greenland) are described in some detail as the best documented cases. Atlas copper mine (The Philippines) is less fully described due to relative lack of documentation. The Misima and Atlas STD systems are working to their design criteria. At Black Angel the system adopted did not prevent contamination for a number of reasons, which are now understood. Two cases are described where STD is being developed. They are the Cayeli Bakir copper mine Turkey), and the Toquepala and Cuajone mines (Peru). There is excellent documentation available for both cases. Three case histories are described where tailings have reached the sea either through beach or river discharge. In one case the STD option has been explored (Marcopper Mine, The Philippines). In the others we explore in hindsight whether STD might have been a viable alternative using the Screening Criteria that this Volume develops - see below. The mines are Bougainville Copper Mine in Papua New Guinea, and Jordan River Mine (Canada). There is potential for STD at all three sites. Finally, the Volume presents Screening Criteria for appraising STD, based on the experience in design, operation and environmental impact reviewed in the case histories.

Jan 1, 1994

By Thomas L. Theis

The use of a suspended growth system of T. ferrooxidans attached in a film to individual particles of bentonite and operated as a sequencing batch reactor has been shown to be a practical way of oxidizing ferrous iron in acid mine drainage. This component followed by limestone neutralization is both a technically and economically feasible approach to the treatment of these wastewaters in comparison to existing and proposed methods. The advantages, in addition to less expense, are greater safety, acceptable treatment at a lower pH, lower solids buildup, less danger of overtreatment, and greater flexibility in operational characteristics. In this report data on the continuous bench scale operation of the system under a variety of conditions shows sustained levels of oxidation in excess of 9%. A cost analysis projects capital and operating costs of $80/1,000 m3 of wastewater.

Jan 1, 1982

By David E. Siskind

The U.S. Bureau of Mines and the State of Indiana cooperated with AMAX Coal Co. and its consultants to determine the effects of coal mine overburden blasting on nearby pipelines. Five pressurized 76-m pipeline sections were installed on the Minnehaha Mine highwall near Sullivan, IN, for testing to failure. Four 17-to 51-cm-diameter welded steel pipes and one 22-cm PVC pipe were monitored for vibration, strain, and pressure for a period of 6 months while production blasting advanced up to the test pipeline field. In contrast to previous studies of small-scale, close-in blasting for construction, these tests involved overburden blasts of up to 950 kg per delay in 31-cm blastholes. Analyses found low pipe responses, strains, and calculated stresses from even large blasts. Ground vibrations of 120 to 250 mm/s produced worst case strains that were about 25 pct of the strains resulting from normal pipeline operations and calculated stresses of only about 10 to 18 pct of the ultimate tensile strength. No pressurization failures or permanent strains occurred even at vibration amplitudes of 600 mm/s.

Jan 1, 2010

By J. R. Thoenen

This circular is part 6 of the third paper (entitled "Excavation") of a series summarizing the technical problems involved in the production and preparation of sand and gravel. Part 1 discussed the use of power shovels, draglines, and excavator cranes; part 2, power scrapers, slackline cableway excavators, and hydraulic monitors; part 3, hydraulic, clamshall, ladder, and diaper dredges; part 4, haulage equipment, particularly industrial cars with locomotive or hoist as the motive power; part 5, conveyor belt, motor truck, pump and pipe line, towboat and barges, and aerial-trams haulage. This circular discusses the application of these various types of equipment to the different types of sand and gravel deposits and contains a reference bibliography. It completes the discussion of excavating problems.

Jan 1, 1936

By Paul L. Michael

Roof warring signals from eleven underground coal mines (principally in the Pittsburgh seam) were studied and analyzed. The character of individual acoustic warning signals is shown to be dependent on spectral distribution of energy. Reverberation tires (pulse decay rates) were found to be usually between 0.1 and 0.5 seconds. Listening tests were conducted to assess the miner's ability to discriminate speech and roof talk signals in noise and in quiet, with and without ear protectors and with various levels of hearing loss. The ability to detect roof talk is shown to be generally degraded while wearing car protection in quiet, although, if car protectors are worn only when required by high noise levels, the ability to detect roof talk will be preserved at its maximum.

Jan 1, 1972

By F. A. Penning

This report describes the development of skip and guide desings for vertical shafts in deep vein mines. Skip and guide systems for bottom dump skips are identified as being used in current practice. Mine visits were made to obtain current information on the needs and problems of operating mines. Methods of structural and mechanical analysis of skip bodies and bails are outlined. A dynamic computer model was written to find the dynamic interaction between skips and guides for guides with geometric misalinements. A materials evaluation section identifies currentavailable and applicable materials that can be used effectively for new skip construction. Guide materials are also presented. Analysis includes the economies resulting from streamlined buntons and from low skip payload ratios. Selection of materials is based on strength, abra¬sion and corrosion resistance. Design requirements related to the shaft environment are presented. Consideration for the selection of guides and buntons is also given. Conceptual design includes the concept of cylindrical skips, center-seeking guide rollers, and asymmetric bail design to decrease dynamic interaction. An outline for field tests is presented. Future research areas are: testing, guide geometry measure¬ment, advanced suspension, dynamics, and structural configurations.

Jan 1, 1977

By R. L. Marek

The number of persons fatally injured in the California petroleum industry, in 1932 was 24, a decrease of 6, or 20 percent from the number killed in 1931. The decrease in the number of fatalities occurring in 1932 caused the fatality curve of the California petroleum industry to reach its lowest point in 10 years. Changing conditions in the oil industry--reduced personnel, decreased active field development, and curtailed production--have undoubtedly caused a part of this decrease, but continued accident-prevention efforts by the industry have also contributed to the reduction in the number of fatalities for 1932. The Bureau of Mines has analyzed and reported annually the fatalities in the California petroleum industry for a period of 10 years. Figure 1 shows the trend of fatal accidents during that period.

Jan 1, 1933

A system to continuously measure the concentration of radon in mine ventilating air has been developed and tested in a uranium mine. In use, the air/radon mixture to be monitored is pumped through filters into a scintillation cell where nuclear decay of the radon produces flashes of light. These are electronically counted, giving a quantitative measure of the radon present. Air is continuously drawn from the mine atmosphere into the radon sensor box. This air sample passes through two filters into the detector cell as shown in the schematic diagram. A portion of the radon in the detector cell will experience nuclear decay, producing polomium 218 and an alpha particle. The alpha particles from the fraction that decays strike a zinc-sulfide coating on the inside wall of the cell and produce flashes of light. These enter a photo-multiplier tube which records each flash as an electrical pulse. An amplifier increases the voltage of each pulse, allowing electronic screening to remove noise and other undesirable pulses. The remaining pulses are counted by a conventional data acquisition system.

Jan 1, 1978

By J. D. Noll

Elemental carbon (EC) is used as a surrogate for regulating the exposure to diesel particulate matter (DPM) of underground metal/non-metal miners. EC was chosen as a surrogate because EC is selective to DPM and is a major component of DPM. Using EC as a surrogate also gives one the advantages of no sampling artifacts and being able to sample at all locations in the mine. Currently, EC represents DPM well in underground mines. Some control technologies have been shown to possibly alter the relationship between DPM and EC and characteristics of DPM. Therefore, future work will investigate the relationship between DPM and EC as new control technologies are implemented.

Jan 1, 2002

By Richard A. Winters

There are no producing or developing mines or active mining claims in the Deschutes Canyon RARE II study area. Only two prospects were found; they have no identified potential for mineral resources. Thin diatomite deposits occur in the Pliocene Madras Formation. Development of sand and gravel deposits in the area could not favorably compete with similar deposits in the surrounding area which are closer to points of use. By mid-1982, active oil and gas lease applications covered about 25 percent of the area, a reduction from nearly 100 percent in early 1981. No holes were drilled for oil and gas exploration. INTRODUCTION Personnel of the Bureau of Mines, Western Field Operations Center conducted a mineral investigation of the Deschutes Canyon RARE II area during the summer of 1982. The area, about 10 mi (16 km) southwest of Madras, Oregon, covers 10,890 acres (4,407 ha) in the Crooked River National Grasslands (fig. 1). The Deschutes River has incised a deep canyon into the north sloping elevated lava plain near the transitional boundary of the High Lava Plains and the Deschutes-Umatilla Plateau geomorphic divisions (Baldwin, 1964, p. 20).

Jan 1, 1983

By Bruce Rock

A continuous mining machine was redesigned for the installation of an integrated illumination system. The illumination system was designed by first calculating the theoretical number of luminaires required to meet the Federal Illumination Standards. Luminaires initially were placed using isointensity diagrams. A darkroom was used for "fine tuning" and demonstrating that the system met the illumination requirements. The luminaire mounts were installed on a machine underground. The performance of this illumination system was monitored in the working environment of an operating coal mine. Design changes were made as necessary during this evaluation period to improve the system.

Jan 1, 1979

By James A. Wasson

This report summarizes the results and conclusions reached by various investigators who have attempted to determine the extent to which hydraulic fracturing will affect the secondary recovery of crude oil by waterflooding. It also discusses the most advantageous use of this well-stimulation method in waterflood projects. A thorough search of the literature was made, and pertinent information was abstracted from appropriate reports. A carefully designed and controlled program of formation fracturing is an effective aid in waterflooding because it increases water-injection and oil-production rates. Generally, fracturing has resulted in little or no reduction in ultimate oil recovery, but under certain circumstances recovery has been substantially increased.

Jan 1, 1963