Search Documents

By William H. Pomroy

Fires in underground metal and nonmetal mines pose a threat to the safety of underground miners and to the productive capacity of this Nation's mines. Contaminated air (smoke, carbon monoxide, and other products of combustion) is the primary life safety hazard created by a mine fire. The most reliable defense against the hazard posed by the rapid spread of contaminated air underground is early warning fire detection and rapid evacuation. This Bureau of Mines report describes the design and operation of four prototype early warning fire detection systems, for underground noncoal mines, presently undergoing prolonged in-mine testing by the Bureau. The systems are described within the context of the underground mine environment.

Jan 1, 1985

By J. Douglas Causey

In 1984, at the request of Bureau of Land Management, the U.S. Bureau of Mines studied the 13,730-acre Burnt Lodge (MT-065-278) Wilderness Study Area (WSA) in order to evaluate the mineral resources. The WSA is located in Phillips and Valley Counties, MT, about 55 miles south of Malta adjoining the Charles M. Russell National Wildlife Refuge. It is underlain by near horizontal sedimentary beds of the Hell Creek Formation, Fox Hills Sandstone, and Bearpaw Shale. No mines or prospects were found in the WSA. Bentonitic beds were examined, but are generally less than 1 ft thick and, except where exposed, are deeply buried. Kaolin-bearing sandstone in the Colgate Member of the Foxhills Sandstone was sampled and may have potential for use in structural clay products. However, remoteness and inaccessibility of the area make it unlikely that the material could be economically extracted even though some of the material is marginally useful.

Jan 1, 1985

By H. H. Kellogg

The thermochemical properties of molten solutions in the binaries Cu-Bi, Cu-Sb and Bi-Sb, as well as the ternary Cu-Bi-Sb, have been correlated and described in mathematical form by use of the associated species concept combined with the three-suffix Margules equations to account for the non-idea 1 behavior of the solution species. Agreement of the correlations with experimental data is excellent (relative deviation of less than 2.5% in the values of the activity coefficients) in most cases. The correlations are applicable over the entire composition range of each system, and in the temperature range 700°-1250°C.

Jan 1, 1985

By Brooks J. Klimley, Daniel M. Higgins, Grover R. Castle

Measuring The Economic Viability Of Resource Projects (A Western Surface Coal Project) The bankers approach to the analysis of a new "green fields" mining project is similar but different from the approach that the pining company might take. The purpose of this paper shall be to discuss the techniques that are used by mining companies and bankers as they try to measure the economic viability of mining projects. The analysis of these new projects (by both the mining companies and the banker) is based on a projected revenue stream and not on historical earnings or past perfomance because these projects are start up situations with no history to look to. The starting point in the analysis of these projections is the choice of the assumptions to be used in preparing these projections. After the assumptions have been determined and the projections are prepared then the projections are submitted to various tests in order to determine whether the project measures up to previously agreed upon minimum standards. In order to illustrate the analytical procedures used in evaluating a mineral project the writer has constructed a hypothetical case involving the development of a western surface coal mine (Property). The basic data in connection with this hypothetical new project is described in the next section of this paper. After the Description of the Project is a section which shows the type of analysis that a mining company might prepare in order to approach a bank for a loan and the final section illustrates the type of analysis that a bank might prepare in evaluating this loan request. Description Of The Project or Basic Data In Connection With Undeveloped Western Surface Coal Property An independent mining/geological Consultant's report has been completed on the Property which confirms that the Property contains 175 million tons of economically recoverable coal subdivided into the following reserve categories in accordance with U.S. Bureau of Mines and U.S. Geological Survey definitions: Measured or Proven 90,000,000 Indicated or Probable 50,000,000 Inferred or Possible 35,000,000 The owners of the reserves have chosen to drill up those reserves that are nearest to the subcrop and have not spent as much time on those portions of the Property which are on the fringes of the deposit where the overburden is thicker because the stripping ratio and hence the operating costs and capital requirements are higher down dip. The proven reserves are based on an average thickness of 80 feet, of which a mining recovery of 90% is projected. The overburden thickness varies from 0' to 280' with an average thickness of 127'. The overburden consists mainly of scoria, sandstone, gravel, shale and silty clay. 134 holes were cored (and analysis done on five foot increments) in the measured reserve on the following spacing: 100 foot centers to define the burn line; 1,320 foot centers to define the early mining areas; 2,640 foot centers to identify the later mining areas.

Jan 1, 1985

By A. S. C. Owili-eger

Coal mining is one of the major activities that may affect the natural or existing hydrologic equilibrium of a basin. Consequently, the mining industry is committed to the conservation and protection of the hydrologic balance within and around mining environments. This commitment embodies thorough and careful consideration of the quantitative and qualitative variations and, in general terms, the environmental impacts of mining activity on the natural water systems. A research program was undertaken to study the impacts of full extraction coal mining on the ground water systems at one of the coal basins in the Appalachian region. The primary objective was to provide reliable information for determining the local and possibly the regional effects of longwall mining on well yields, and the hydraulic and hydrogeochemical parameters of the immediate surface and subsurface water resources.

Jan 1, 1985

By John G. Whellock

Over the last decade new constraints have emerged in the metallurgical industry which challenge the very basis of design and construction of smelters and refineries. The hackneyed designs of the past will not now serve the revised objectives of: - minimal cost of ownership - improved productivity - reduced energy consumption - greater flexibility in feed or product - minimized recycle loops and by-products - more stringent environmental control The impact of these constraints has been channeled constructively into process intensification - exemplified at the large scale by the introduction of flash smelting technology and at the smaller scale by the application of rotary process vessels and converters for augmented heat and mass transfer. The design of successful process plants depends on the understanding of the unit operations and their interactions which is the discipline of systems engineering. With the advent of increased process intensification the importance of a systems approach to process design and implementation becomes paramount. This paper describes the systems approach with specific reference to medium scale projects in the primary and secondary metallurgical industry.

Jan 1, 1985

By Michael E. Henderson

The U.S. Bureau of Mines (BOM) constructed the Hydraulic Transport Research Facility (HTRF) to investigate the hydraulic parameters relating to the transport of coarse coal. To achieve these goals in a timely and efficient manner, the Bureau contracted to Boeing Services International, Inc. (BSI) the responsibility of operating the HTRF and providing technical support. This data report is a summary of the testing and data results for the period from 16 September to 1 November 1983. The testing covered herein is for coarse 2-in by a (minus 50 mm) Pittsburgh Seam coal in a 12-in (3 00 mm) pipeline, at velocities ranging from 5 to 18 ft/s (1.5 to 5.5 m/s) and at concentrations ranging from 15 to 55 pct.

Jan 1, 1985

By Richard A. Watson

A frequency-shift keying (FSK) modulator-demodulator (modem) network has been devised for the Bureau of Mines mine-monitoring systems. This network permits an unlimited number of remote stations to communicate with one central station over the same pair of wires. The network operates at a speed of 4,800 Bd at distances up to 5 miles. This report describes the development and operation of the modems. The theory of operation, schematic diagrams, and printed circuit board layouts are provided. Although the modems were built for a specific application, a more general use is discussed whereby the network would operate with a typical serial channel format.

Jan 1, 1985

By Wesley W. Eckles

Microcomputer technology has begun to revolutionize petroleum engineering. Petroleum engineers' use of relatively inexpensive personal computers (PC's) is likely to continue expanding rapidly. Since 1982 SPE's Microcomputer Applications Committee has developed a Society-wide users group, a bi-monthly newsletter (MICROCOMP NEWS), an SPE Short Course, a hardware and software distribution program, and a world wide electronic network (SPE NET). The purpose of this paper is to share SPE's experience in creating a dynamic program for meeting the individual member's need in the application of microcomputers to petroleum engineering. My hope is that this will encourage other engineering and scientific organizations to provide similar programs for their members.

Jan 1, 1985

By T. H. Jeffers

The Bureau of Mines conducted laboratory tests to devise a procedure for extracting copper from low-grade discarded mill tailings. A solid extractant consisting of an organic solvent extraction reagent adsorbed on granular activated carbon was investigated and proved to be satisfactory for extracting copper directly from leach pulps. When this material was used in a cyclic leaching, stripping, and electrowinning pro-cess, 95 pct of the acid-soluble copper was recovered from oxidized mill tailings. The weathered tailings contained 0.24 pct Cu (total) and 0.20 pct acid-soluble Cu. The copper was recovered as cathodes containing, in parts per million, 1.6 Pb, 3.6 Fe, 0.5 Sb, 1.5 AI, 1.9 Mn, and <1 Mg.

Jan 1, 1985

By J. E. Lonergan

The in-pit placement of crushing and conveying equipment results in a flattening of the pit slope of a multiple-bench open pit mine. To maximize the economic benefit of lower haulage costs associated with in-pit conveying, one must minimize the cost of the flatter slope which is expressed in terms of additional stripping or tied up ore. A computer program that compares the tonnage aspects of various conveyor layouts will be discussed.

Jan 1, 1985

By C. F. Winquist

The Bureau of Mines is engaged in research to evaluate the effects of cutter bit wear at coal mine faces. This paper addresses one element of conical bit wear, bit rotation. A discussion on mounting configura-tion and bit forces and their effects on rotation is presented. The effects on rotation and bit forces of bit attack angle, cutting depth, and skew are determined for two types of conical bits during linear cutting of sandstone-inclusive rock. The results indicate that a 10° negative skew angle and 35° attack angle produce the maximum rotation of 17.5° for each foot of cutting. Data on bit rotation and bit forces are presented in an appendix.

Jan 1, 1985

By Marcie A. Greenberg, John C. Patton, R. Tim Thompson

The Fence Lake Project is located in the Salt Lake coal field, an extension of the San Juan Basin. Geologic formations exposed in the Project area range in age from late Cretaceous to Quaternary. Coal is encountered in the Moreno Hill Formation (upper Cretaceous). Salt River Project (SRP) followed the basic textbook approach for the exploration, regional appraisal, detailed reconnaissance, detailed surface detailed and three dimensional sampling (physical exploration). SRP is exploring this property as a potential fuel source for the Coronado Generating Station. Therefore, for the physical exploration stage, the quality sampling program was designed from a utility company viewpoint to determine possible impacts to the Station. Exploration drilling was completed in spring, 1982; September, 1982, and summer, 1984. Engineering, environmental, and land acquisition studies - in the Summer, 1984 Program to more closely evaluate the potential Fence Lake Project coal supply option for the Coronado Generating Station. Studies, including drilling, are ongoing at this time.

Jan 1, 1985

By J. A. Meech

An analysis of screen design options on the operating efficiency of secondary crushing plants has been conducted using a dynamic computer model. The model allows for the simulation of a wide variety of crushing circuits and can be run on either a microcomputer (IBM PC/XT) or a large time-sharing mainframe computer. Size reduction and separation characteristics of crushers and screens are based on standard manufacturer design and performance data. Input/output routines are available in tabular, alarm or strip chart recorder modes to facilitate operation of the program. A number of alternate circuit designs are compared to show the influence of surge capacity, screen size and area, screen deck location, and closed side crusher settings on the operation of a 10,000 ton per day plant. The program is currently in use at Queen&apos;s University to teach plant operations and control. It has potential to be a valuable tool for operator training.

Jan 1, 1985

By Pamela J. Watson

This report presents a Bureau of Mines literature survey that provides a data base useful for current and future studies in the area of chemically enhanced drilling and cutting. Publications describing laboratory testing and field studies of drilling and cutting with chemical additives are reviewed. Significant results are summarized and tabulated by rock or material type and also by chemical additive, with extensive references. Selected studies related to fluid-enhanced processing or material testing are summarized in the appendixes.

Jan 1, 1985

By W. S. Cavender

The Round Mountain mining district, Nye County, Ne- vada, was discovered in 1906 on claims owned by Lewis D. Gordon. Initial mining operations uncovered gold veins of spectacular richness, and within a few days of discovery, Gordon sold his controlling interest for some $87,000. From this sale emerged the Round Mountain Mining Co., predecessor of Nevada Porphyry Gold Mines, Inc., the latter destined to become the major property owner in the area. Vein mining in the district continued sporadically into the early 1930s, yielding 9.3 Mg (330,000 oz) of gold plus substantial silver credits from approximately 626 kt (690,000 st) of ore. In addition to the lode deposits, the early miners recognized the placer potential in the alluvial fan material accumulated around the west and north sides of Round Mountain itself. Intermittent placer operations were carried out for a number of years, and in the 1940s and 1950s, Round Mountain Gold Dredging Co. worked the placers under a lease from Nevada Porphyry Gold Mines. The last placer operation terminated in 1959 when it, like some of its predecessors, proved uneconomic. Total placer production for the district is estimated at 3657 km (4 million yd) of gravel containing 59 Mg (210,000 oz) of gold and possibly 2.0 to 2.3 Mg (70,000 to 80,000 oz) of silver. Round Mountain is a small hill situated on the east flank of the Toquima Range in central Nevada. The hill is com- posed of relatively flat-lying Tertiary rhyolitic ash flow tuffs, which overlie Paleozoic metasediments and Cretaceous granites. Throughout the surrounding Round Mountain mining district, most of the known gold ores occur in the tuffs, although the metasediments and granites are also mineralized. Mineralization is structurally controlled, principally by a series of northwest-trending shears and shattered zones. Vein, stockwork, and disseminated ores occur, usually containing simple quartz-pyrite-gold mineral assemblages. The gold itself is electrum, having a silver content of 30% to 40%. In September, 1967, Elwood Dietrich, a prospector and mine promoter, obtained a purchase option on the 4452 ha (1 1,000 acres) of mineral rights held at Round Mountain by Nevada Porphyry Gold Mines. The original option had a buy-out price of $1 million and was established through Dietrich&apos;s friendship with officers of Nevada Porphyry. In April, 1968, Dietrich conveyed his option to Ordrich Gold Reserves Co., a partnership created by a group of west coast investors, mostly employees of the airline industry. There- after, Ordrich invested considerable funds in trying to test and develop the property, but soon recognized the need to seek financial and technical support from the mining industry. In December, 1968, Dietrich contacted Wayne Cavender, then Regional Geologist, Southwest, for Copper Range Exploration Company (CRX) in Tucson, Arizona, and made a data presentation. Shortly thereafter, Cavender was appointed Manager of Exploration and Chief Geologist for Copper Range Co. (parent company of CRX), New York City, and he asked C. Phillips Purdy, CRX Regional Geologist, Northwest, to make an initial property examination. Purdy&apos;s one-week field study took place in March, 1969, and resulted in a recommendation that CRX pursue its investigation of the property. The presence of low-grade gold mineralization in both the alluvial gravels and in the bedrock was verifiable, but the placer was deemed to have the greater immediate economic mining potential. At that time, gold was in the $1.41/g ($40 per oz) price range. Working from Purdy&apos;s information, Cavender decided to attempt acquisition of the property, and the first in a long series of negotiations was initiated with Ordrich. Basically, CRX felt that the placer had a promising potential for several reasons, including (I) past operators had recovered free gold but not the gold contained in the pebble fraction of the gravels; (2) past operations appeared to have been ineffectively designed or managed and not costefficient; and (3) the price of gold appeared to be poised for an upward move. Negotiations with Ordrich were prolonged and difficult, with CRX competing against several ma* mining companies, but finally an agreement was reached, effective June I, 1970. Gold was then back to $35. It is believed that, in

Jan 1, 1985

By Peter A. Rona

Hydrothermal mineralization along slow-spreading oceanic ridges and rift -zones that comprise more than half the global length of the seafloor spreading center system is related to anomalous physical and chemical conditions acting within the geologic settings that characterize early and advanced stages of opening of an ocean basin. Mineralization in the early stage of opening is represented by the Atlantis II Deep of the Red Sea. There, hypersaline hydrothermal solutions discharging as density stratified brines into an axial basin, have formed the largest massive sulfide deposit (70 x 106 metric tons) known at a spreading center. Mineralization at the advanced stage of opening is represented by two types of sites: (1) oceanic crust on the wall of a rift valley; and (2) oceanic crust exposed on the wall of a transform fault zone. The first type of site is the TAG Hydrothermal Field, located on a wall of the rift valley of the Mid-Atlantic Ridge at the top of the basaltic layer of oceanic crust. Evidence is presented for multi-stage, high- and low-temperature hydrothermal activity that produces Cu, Fe, and Zn enrichments within the thin sediment column and stratiform interlayered deposits of manganese oxides, iron oxides, hydroxides and silicates, on the seafloor. The second type of site occurs along walls of transform fault zones of the equatorial Mid-Atlantic Ridge and Carlsberg Ridge, which exhibit stockwork-type Cu-Fe sulfide mineralization

Jan 1, 1985

By R. P. Vinson

The Bureau of Mines conducted a series of tests to determine how well the Bendix BDX 60, the Gilian HFS 113U, the MSA Fixt-Flo, and the Spectrex PAS-3000 dust sampling pumps control the flow rate at 2 L/min. These tests were performed because users need to know the performance characteristics of sampling pumps to select the pump that best satisfies their sampling requirements. Long-term (6- to 8-h) flow stability at various backpressures was examined in relation to the flow control tolerance of ±5% of the flow, the level imposed by Federal regulations; four of the five Bendix pumps did not meet the criterion for this test, which was passed by all other pumps tested. Flow control recovery times were measured at transient backpressures; all pumps evaluated met the criterion for this test. The low-flow indicators of the sampling pumps were tested; only two Bendix pumps and one Gilian pump met the criterion of indicating a flow change greater than ±5%. In the pulsation flow measurement test all of the pumps passed, with pulsating flows greater than 20 Hz. The Bureau also evaluated the manuals accompanying the sampling pumps. All were judged adequate except the Spectrex manual, which was judged poor.

Jan 1, 1985

By G. F. Ziesing, E. F. Loros, T. J. Smolik

The Golden Sunlight mine began full-scale operations in February 1983 with a conventional open-pit mine supplying 4536 t/d (5000 stpd) of milling ore. After crushing and grinding, the ore is leached with cyanide solution in large agitation tanks. Soluble gold values are removed from the sand portion of the leached ore with five stages of countercurrent washing cyclones. After thickening of the cyclone-wash overflow slurry, the gold is recovered in activated carbon with a six-stage carbon-in-pulp circuit and a five-stage upflow carbon column circuit. Pressure stripping, carbon reactivation, electrowinning, and refining complete the gold recovery process.

Jan 1, 1985

By M. Hayashi

The Bureau of Mines conducted laboratory studies on low-grade vanadiferous silicates from the Pumpkin Buttes and Nine Mile Lake deposits of Wyoming to examine techniques for extracting vanadium and uranium. Recovery from low-grade sources such as these could contribute to future vanadium production and reduce reliance on vanadium imports. The Pumpkin Buttes samples contained 0.03 to 0.04 pct V205 and 0.06 to 0.12 pct U308; the Nine Mile Lake samples contained 0.02 to 1.0 pct V205 and 0.06 to 0.19 pct U308" Leaching the Pumpkin Buttes samples for 18 h at 800 C with addition of 200 lb/ton H2S04 resulted in recoverey of 80 pct of the vanadium contained in the samples. The Nine Mile Lake samples were readily leached, yielding 78 to 94 pct of the vanadium after 3 h at 800 C with addition of 100 lb/ton H2S04, A solvent extraction procedure was used to selectively recover urani-um from Pumpkin Buttes and Nine Mile Lake leach solutions and to recover vanadium from the raffinates. In batch shakeout tests, Alamine 336 recovered over 95 pct of the uranium from leach solution adjusted to pH 1. Di-2-ethylhexyl phosphoric acid and Cyanex 272 recovered vanadium from the uranium raffinate after reduction and adjustment to pH 2; vanadium extractions of up to 96 pet and 92 pct, respectively, were achieved.

Jan 1, 1985