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By H. H. Fukubayashi

This Bureau of Mines report describes the development of a pyrometallurgical process for the recovery of the zinc and lead contained in brass smelter flue dusts, which constitute a recycling or disposal problem. Tests on brass flue dust from several sources were made in a quartz tube, heated by an electric furnace to temperatures as high as 1,050° C. The dusts were mixed with carbon and heated in an oxygen-free atmosphere. It was demonstrated that 98 pct of the zinc and 12 to 25 pct of the lead, both in the metallic state, could readily be removed from the dusts. It was also found that 75 pct of the zinc could be recovered, with less than 0.1 pct of the lead, in the absence of chlorides. Pelletization techniques were investigated and 0.6 inch pellets were found to be optimal. Pelletizing results in a tenfold reduction in volume.

Jan 1, 1974

In the past, mine management has been concerned with removing water from active mining sections primarily because it hampered the movement of mining equipment and aggravated the working condition of the miners. Pumping water to sumps and gravity drainage by ditching have proven successful in mines for minimizing section down time due to water influx. However, with the advent of more strict pollution laws the mining engineer must now be concerned with keeping water out of the section and also with preventing it from causing pollution. A review of the handbooks and textbooks used in the mining engineering curricula reveals that little has been written concerning acid mine water prevention or control in underground coal mines. Additionally, the review of the curricula of mining schools indicates they are not teaching the engineering students the necessary techniques of mine water management as they relate to the abatement of mine water pollution.

Jan 1, 1970

Develop a means for analyzing seismic crosshole data to predict and monitor the Flow of leach solution during in situ mining. Background Improvements in predicting and monitoring in situ leach solution flow would aid in planning well field configurations. These improvements would also facilitate permit application by assuring regulatory agencies that leach solution would not escape from a well field undetected. Seismic tomography can detect fractured zones, which enables the prediction of probable flow paths, and it is a promising technique for monitoring leach solution injected above the water table. Tomographic analysis of crosshole seismic data provides a two-dimensional picture of the distribution of seismic velocities between the transmitter and receiver boreholes. The positions of fractured zones and of leach solution can then be inferred from the seismic velocities.

Jan 1, 1989

By E. R. Cole

A lead smelting process that appears to present minimal pollution problems has been developed at the Bureau of Mines, Rolla Metallurgy Research Center. Ten and 100 g samples of PbS mill concentrates were vaporized at 1,000° to 1,100° C in a furnace with an inert gas atmosphere during a 2-hour period. The PbS vapor was transported by the inert carrier gas to the reduction zone of the furnace where it was reduced at the same temperature with excess hydrogen to metallic lead. Lead of 99.9 pct purity was produced. The H2S formed can be decomposed into elemental sulfur and water vapor by a modified Claus process. Approximately 90 pet of the Cu and 70 pct of the Ag and Zn remain in the residue and are potentially recoverable. More than 98 pct of the lead in the concentrates was extracted.

Jan 1, 1974

By Thomas F. Tomb

The penetration characteristics of a horizontal plate elutriator and of a 10-mm nylon cyclone were evaluated. The test aerosols were polydisperse coal-dust particles ranging from less than 0.3 to 15 micrometers in diameter. Particle densities ranged from 1.3 to 1.4 grams per cubic centimeter. Equivalent Stokes diameters were measured using Coulter counter analytical techniques. Experimental results indicate that the penetration characteristics of the horizontal plate elutriator closely approximate the sampling efficiency curve defining the respirable fraction of the dust cloud recommended and adopted by the Johannesburg Pneumoconiosis Conference in 1959. Penetration characteris-tics of the 10-mm cyclone were evaluated at flow rates of 1.4, 1.5, 2.0, 2.5, and 2.8 liters of air per minute. The data indicate that the penetration curve obtained at 2.0 liters per minute most closely approximates the sampling efficiency curve for respirable dust recommended at a meeting sponsored by the U.S. Atomic Energy Commission in 1961.

Jan 1, 1970

By David Hoadley, Kenneth R. Maser, Ashok B. Boghani, James E. Billar, D. Randolph Berry, Mackenzie Burnett, Robert H. Trent

2, Survey of Representative Group of Metal and Non-mental Mines Before proceeding to develop and analyze Emergency Escape System Guidelines, it was necessary to obtain a broad range of information, including both fact and opinion. Although there were many areas to consider, the surveys had three primary goals 1. To determine the current state of underground escapeway planning and execution in American, metal and non-metal mines. 2. To determine, for a wide range of mining conditions, what difficulties can be encountered in complying with present and proposed escapeway regulatory standards. 3. To determine what improvements could be made and what equipment and technology was available to aid in implementing these improvements. To accomplish these goals, three major surveys were undertaken¬ 1. Survey of MESA and State Mining officials, discussed in Section 2. 1. 2. Survey of representative U S metal and non-metal mines, discussed in Section 2. 2. 3. Survey of manufacturers supplying equipment, primarily hoisting, suitable for use in escape systems, the product information which was obtained is discussed in Section 7.

Jan 1, 1976

By W. K. Overbey

Knowledge of fracture systems in oil or gas reservoirs is essential to the efficiency of both primary and secondary production operations. A relationship was established between structural features of the surface and both natural and induced fractures in oil and gas reservoirs, thus providing a method of predicting the direction of rock fracture prior to field development and well completion. Correlations between the surface features and under-ground fractures resulted from analysis of joint strike measurements, bottom-hole impression packer surveys, photographs of hydraulically fractured wells, fracture data from oriented cores, in situ strain measurements from formation outcrops, and lineament analyses from aerial photographs. The mean orientation of surface fractures, lineaments, and stress field directions ranged from N 53° E to N 73° E, compared with an average orientation of N 63° E for the hydraulically induced fractures. Tectonic stress field was shown to influence the direction of hydraulically induced fractures. This report presents the details and application of techniques to obtain the orientation of the principal horizontal compressive stress field component and thus the direction of induced fractures.

Jan 1, 1971

By William J. Wiehagen

This is the third in a series of four articles that discuss underground fire-fighting preparedness. As with the first two articles, it is based on interviews with 214 miners conducted at 7 underground coal mines (referred to as Mines ?A? through ?G?) by researchers of the National Institute for Occupational Safety and Health?s (NIOSH) Pittsburgh Research Center [Vaught et al. 1996]. In the first article, the authors presented an overview of the study conducted by NIOSH on mine fire response preparedness and provided a general perspective on underground mine fires. The second article discussed miners? preparedness to evacuate a fire and their experience with incipient fires. In this article, we describe miners? experience in fighting underground mine fires and present their perceptions of training and readiness for fire-fighting.

Jan 1, 1997

By M. A. Trevits, S. W. Lambert

In this Bureau of Mines investigation, production was monitored for 1 year at over 30 coalbed gas-drainage boreholes located in Alabama, Pennsylvania, and West Virginia. Results indicate that the quality of data gathered from such wells can be improved greatly if potential problems are anticipated and prevented in the early stages of well production. Major water-monitoring problems include solids buildup, freezing, the presence of gas in surface waterlines, and improper pumping interval settings. Such problems may be avoided by incorporating in the original well design waterline filters, sand screens, separator tanks, and systems to automatically control pumping intervals. Problems related to measurement of coalbed gas flow include large quantities of water vapor contained in the gas, especially during winter months; freezing and subsequent obstruction of flow; sudden, uncontrolled release of gas pressure; and solids buildup in metering equipment. The installation of commercially available items, such as filters, separators, and insulation, and the thoughtful application of a basic knowledge of coalbed gas reservoir characteristics will prevent most production-monitoring problems.

Jan 1, 1978

By W. H. Eddy

The Bureau of Mines conducted laboratory batch-and small-scale continuous flotation processing tests on waste granite fines from Georgia, to determine the feasibility of recovering usable feldspar and quartz products by flotation. Two flotation methods were utilized for the removal of biotite and other iron-bearing minerals: One was in an acid-cationic circuit, and the other in an alkaline-anionic-cationic circuit. Feldspar was recovered using an acid-cationic method. To produce commercial-grade feldspar and quartz products it was necessary to employ either two sequential froth flotation circuits or one froth flotation circuit supplemented by wet-magnetic separation techniques to remove iron contaminants. Continuous flotation processing yielded a commercial-grade feldspar concentrate containing, in percent, 3.8 Na20, 5.4 K20, and 1.10 CaO, with recoveries of 77.8, 70.3, and 64.4, respectively. The feldspar tailing was high-quality glass sand containing 98.2 percent SiO2 and 0.024 percent Fe2O3. About 42 percent of the quartz was recovered at glass sand specifications. An effective separation of, potash feldspar from the bulk feldspar concentrate was achieved by batch flotation in a mineral separation cell.

Jan 1, 1974

By Kevin Connor

Exports of agricultural products, mostly coffee, continued to account for more than 90% of Burundi's foreign exchange revenue. The country's ban on commercial mining was lifted in 1987. Mining of peat for fuel, limestone for agriculture, and clay for insecticides continued as in previous years. At yearend, Burundi's external debt stood at almost $700 million.2 Amoco Burundi, a subsidiary of the Amoco Petroleum Co., drilled two exploration wells in northern Lake Tanganyika in 1987. No oil was found, but preliminary findings were encouraging enough that further seismic surveys and offshore and onshore drilling exploration were planned in 1988. Any oil or gas finds would have substantial impact on the Burundian economy because a major portion of the country's trade deficit was directly attributable to petroleum and gas imports. The Zaire Government agreed in June to let Amoco Burundi explore Zaire's side of Tanganyika using the same equipment and personnel being used in Burundi.

Jan 1, 1989

Reduce spillage hazards and contamination when adding hydraulic nil to mining machine reservoirs. Approach An easily transported module, that delivers hydraulic oil directly into mining machines, was built and tested. How It Works The Hydraulic Oil Delivery Module is carried, from the oil storage area to the equipment needing oil, in the bucket of a scoop or other utility vehicle. Oil is pumped into the module reservoir from storage, or out of the module reservoir into the machine being serviced, through a long hydraulic hose. During long-term testing, the 115 foot long delivery hose made it possible to replenish the hydraulic oil in mining machines at the face with only limited interruption to the mining operation. (Figure 1 shows one! version of the module.) The compact Hydraulic, Oil Delivery Module consists of: an oil reservoir: a pump driven by a hydraulic motor; two high pressure, low volume oil lines, filters; and a low pressure, larger capacity delivery hose equipped with quick-connect-couplers. The high pressure oil lines are connected to the scoop's hydraulic power takeoff, which supplies the power to pump oil in or out of the module reservoir.

Jan 1, 1977

By A. F. Colombo

In an effort to maintain an adequate supply of iron to meet national economic and strategic needs, the Bureau of Mines, U.S. Department of the Interior, is conducting research on methods for beneficiating the oxidized taconite resources located on the western Mesabi range in Minnesota, thus expanding domestic iron ore reserves. The selective flocculation and cationic flotation process was investigated in a pilot plant using an ore feed rate of 410 kg/hr (900 1b/hr) and 88 percent recycled water. Lime and a cationic flocculant were used to clarify the waste slurries treated in the water reclamation circuit. An oxidized taconite assaying approximately 36 percent Fe yielded concentrates averaging 63.5 percent Fe and 4.3 percent SiO2 and having an average iron recovery of 84.4 percent. The estimated reagent cost per tonne of concentrate was approximately $1.10. In an attempt to recover more of the iron lost in the flotation tailing, wet high-intensity magnetic (WHIM) separation was incorporated in the pilot plant circuit. The flotation concentrate grades obtained from beneficiation circuits with and without WHIM scavenging were similar, but when WHIM separation was used the overall iron recovery was increased by 2 to 9.5 percent, depending on the iron assay of the flotation tailing.

Jan 1, 1978

By P. A. Bloom

Arsenic-containing flue dusts are currently being stockpiled by several nonferrous smelters in the United States. These stockpiles are a source of environmental concern since the dusts can be transported by wind and contain water-soluble arsenic. The stockpiles also represent an alternate source of metals. To provide a quality environment, the Bureau of Mines investigated a process to make environmentally acceptable the discard of arsenic obtained from the treatment of arsenical flue dust. The process includes (1) leaching arsenic from a lead smelter copper dross flue dust, (2) fixing arsenic as an insoluble compound, and (3) recovering other metal values. Overall results of acid-leaching tests on lead-smelter flue dusts showed that H2S04 dissolved 80 to 90 percent of the As, Zn, and Cd, and up to 86 percent of the In. Pb, Ag, and Au remain in the residue, which can be recycled to the smelter. Indium was recovered from the strong acid leach solution by solvent extraction; arsenic was fixed in a stable form by precipitation with Fe2(S04)3 and CaO or CaC03.

Jan 1, 1982

Improve underground long-hole drilling efficiency and safety by developing a lightweight, easily transportable drilling pust that can be adjusted to fit a range of mine opening heights. Background Standard one-piece commercially available steel posts weigh approximately 10 pounds per foot. Transporting these posts underground and carrying them over obstacles and through small mine doors is very difficult. Because the length of a one-piece post cannot be adjusted, variations in mine opening height at the drilling site must be accommodated. This is accomplished by stacking several wooden blocks to form a base for the post, resulting in a dangerously unstable drilling setup. The only alternative to this unstable setup is to obtain a longer post. There problems can be reduced by the use of a two-piece telescoping aluminum post having a 3-foot adjustment range in 6-inch increments. The two-piece extendable post will be easy to transport and carry underground. It will fit any opening height within its adjustment range. One large wooden block is used as a base and one cap block is used at the top to bear against the mine roof. This arrangement results in a stable, rigid setup.

Jan 1, 1990

By Joseph C. Zelanko, Anthony T. Iannacchione

One of the most difficult and longstanding engineering problems associated with coal mining is the catastrophic failure phenomenon known as coal mine bursts (known in the United States as bumps). For more than 70 years, researchers and practitioners have attempted to determine whether this destruction observed underground is caused by stress conditions within the coal pillar or from distant seismic sources in the mine roof and floor strata. The role of confinement and the extent of failure in solid pillars and panels have also proven difficult to define. These are important issues, since control solutions need to be based on a fundamental understanding of the problem. Obsenations by U.S. Bureau of Mines researchers over the last decade have helped to clarify certain aspects of these issues. Microseismic sensors and geomechanic field measurements have located areas of excess energy release, identified stress conditions in coalbeds close to failure, and recorded the response of mine structures prone to bursts. In the present study, data available for a range of U.S. bursts were considered in an effort to evaluate both common and distinctive features. Although the attempt revealed little commonality, encouraging results were produced by categorizing coal bursts by source mechanisms. When a coal burst is thus categorized, differences in environmental factors-such as geology, stress fields, and mining methods-are highlighted, and viable control strategies are readily recognized.

By James P. Rider

This U.S. Bureau of Mines report describes a viewing transformation algorithm that generates a perspective view of a three-dimensional scene. This tool may be used by researchers to improve mine safety by assessing the visual capabilities of a mobile equipment operator. Three-dimensional transformations used to build the viewing transformation and techniques used to project the image onto a two-dimensional display screen are defined. The algorithm is written in the C-programming language and designed to stress portability, allowing it to work without significant modifications on numerous computers. A listing of the computer routines along with sample output is included in the report.

Jan 1, 1992

By Jack C. White

The purpose of this Bureau of Mines work was to develop information useful in improving copper recovery during copper milling operations. Eleven copper mill tailings from the Western United States were subjected to froth flotation and cyanide leaching to provide an experimental basis for comparing their beneficiation response. Recoveries in flotation concentrates made from mill tailings ranged from 65 to 15 percent, at copper grades of 13 and 2.2 percent, respectively. Liberated copper sulfide minerals present in two samples were readily recovered by laboratory froth flotation. Nine of the samples were less amenable to froth flotation because of physical locking between copper sulfide minerals and gangue. Correlations among tailings indicated that recovery of sulfide copper by flotation was directly related to the sulfide copper content. Empirical equations derived from flotation data provided average values for unrecoverable copper and for recovery efficiency. Flotation response of copper mill tailings may be predicted from the equations. Data from cyanide leaching provides an equation describing the limiting high values for removal of copper by this method.

Jan 1, 1974

A construction material based on plasticized sulfur and mineral aggregate, that is superior in corrosion resistance and strength to portland cement concrete. The material can be used in the chemical, metallurgical, and fertilizer industries, and will also provide an attractive market for by-product sulfur resulting from compliance with pollution regulations. How It Is Made Sulfur concrete is thermoplastic material. Plasticized sulfur is mixed with sand and gravel aggregate heated to 375-400° F. The sulfur melts and acts as the binder or cement. The sulfur concrete is poured hot and sets at a temperature of 200° F. Full strength is attained in a few hours, compared to several days for portland cement concretes. Sulfur concrete even pours and sets in freezing weather. Although unmodified sulfur with aggregate will produce a sulfur concrete with good initial properties, it undergoes crystallographic modifications, and deteriorates with time, particularly when exposed to moisture or freeze-thaw conditions. The Bureau of Mines has developed plasticizers which, when reacted with the sulfur, give sulfur concretes with excellent moisture and freeze-thaw resistance. The plasticizers are based on mixtures of dicyclopentadlene (DCPD) and ollgomers of cyclopentadiene. About 5 percent by weight of the plasticizers is reacted with molten sui fur for several hours. The sulfur cement can be used directly or allowed to solidify for easier handling and storage.

Jan 1, 1981

By Kevin Connor

The Government's ban on all commercial mining operations, except for small-scale artisan exploitation of alluvial gold deposits, continued throughout 1985. Minerals produced were kaolin and lime for agricultural uses, and experimental peat harvesting for energy applications. The total value of the minerals produced during the year was estimated at $1.1 million .2 In early 1985, an agreement between the Government and Amoco International Oil Co. was ratified for a petroleum exploration concession covering 248,000 hectares of Lake Tanganyika. Onshore exploration in the Ruzizi Plain was already under way the last half of 1985. By yearend, enough seismic information was available that Amoco hoped to complete data analyses, determine onshore drilling sites, and begin drilling operations before the end of 1986. Also to begin in the latter part of 1986 were seismic studies of Lake Tanganyika. Throughout 1985, Amoco officials were negotiating with the Government of Zaire for expanding the exploration acreage into that country's portion of northern Lake Tanganyika and the Ruzizi Plain. An agreement between Amoco and Zaire could have important beneficial economic implications for both Zaire and Burundi, and onshore seismic work in Zaire logistically supported from Bujumburi could begin almost immediately.

Jan 1, 1987