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By M. S. Klima, M. Fofana

The use of a laboratory-scale magnetic fluid-based separator for coal separations was examined. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two separation chambers, which were constructed of Plexiglas, were designed to fit between the pole pieces. A commercially available, water-based, ferromagnetic fluid was used as the separating medium. The separating density was changed by varying the current intensity of the electromagnet coil. Both batch and continuous separations were made using 0.59 x 0.50-mm and 0.18 x 0. 15-mm coal. The results are compared to those obtained using organic liquids.

Jan 1, 1998

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the micro- computer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user pro- grams to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to en- courage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Har- mon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the com- puterized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage ) , the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 1, 1988

By A. E. Hall

The authors are to be commended for their attempt to provide a convenient piece of software for preliminary drum hoist specification. This field has received little attention in recent years and is eminently suited to calculation by computer. Unfortunately, there appears to be an error in the calculation of the required rope diameter. The 66-mm (2 5/8-in.) rope selected is oversized for this application. Wire rope weight and breaking strength are related to the rope diameter. For a round strand rope

Jan 1, 1988

By İbrahim Gunes, ATILA GURHAN CELIK, Eren Komurlu

This study introduces a new apparatus designed to improve the load-bearing capacities and insertion efficiency of split set type friction bolts. Laboratory and site studies demonstrated the apparatus’s advantages in terms of practicality and prevention of buckling. The apparatus temporarily compresses the split tubes, reducing friction during insertion and increasing normal stresses and friction capacity at the bolt-rock contacts.

Jan 3, 2022

By EREN KOMURLUR, ATILA GURHAN CELIK, IBRAHIM GUNES

In this study, laboratory and site studies were performed to investigate the usability of a new insertion apparatus designed for the split-set type of friction bolts. The new apparatus decreases the friction during the bolt insertion by a temporary diametric compression of the split tubes. According to the results, the new precompression apparatus was found to be advantageous in terms of the insertion practicality and prevention of the buckling problem. By allowing increases in the ratio of bolt diameter to drill-hole diameter, the new apparatus was found to supply relatively high normal stresses and friction capacity in drill holes after opening its clamping mechanism.

By Jacques Monette

Gold and silver cyanide complexes are presently desorbed from activated carbon by means of hot caustic elutions. These solutions may or may not contain additional sodium cyanide. There are several parameters which affect the rate of stripping. Some of these include pH, ionic strength, and tempera­ture. Stripping is conducted in recirculating (ZADRA) or once through (AARL) circuits. This paper describes the development of a new chemical eluant which increases the rate of stripping of both gold and silver cyanide complexes from carbon. Two case history applications are described.

Jan 1, 1995

By G. V. Borquez

For many years drilling and blasting has been considered more of an art than a science. This is still true in some respects, but today scientific approaches to drilling and blasting design must be used to plan an efficient operation which achieves desired fragmentation within constraints. These constraints involve minimizing damage to the wall or nearby permanent structures and avoiding undesirable fragmentation and mine dilution which can adversely affect operation costs. The degree of fragmentation by blasting is the most important single factor in any attempt to optimize the overall cost of the mining operations. The mining cycle begins with the drilling and blasting operations, which result in a given blasted rock size distribution. While this operation represents only about 20% of total mining costs, the efficiency and costs of the subsequent operations are strongly dependent on the fragment distribution obtained.

Jan 1, 1986

By W. J. Whiten

A rule-based control system was developed for a 7-foot Hydrocone crusher with automatic set regulation, based on operating data collected in the field. When implemented in a plant PLC, the system was found to behave as predicted. Benefits included a significant reduction in the frequency of control actions, the incidence of power overloads, and the standard deviation of feeder speed, whilst maintaining crusher performance.

Jan 1, 1992

By J. E. Chilton

Methanometers with catalytic heat- of-combustion sensors used in coal mines today will read low for flammable gases when oxygen (0,) concentrations are low or when methane (CH,) concentrations are greater than 10%. Thus, these methanometers may not be reliable during operations such as fire fighting or recovery of sealed mines. The U.S. Bureau of Mines developed a total flammable gas detector (TFGD) to measure CH, at concentrations up to 100% and to measure flammable gases in low 0, concentrations. This paper describes the operation and construction of the TFGD and discusses measurements of flammable mine gases obtained from a mine in western Pennsylvania.

Jan 1, 1992

By N. C. Miller

In situ stope leaching is an innovative mining system that reduces the surface impacts of conventional underground mining. As in any leaching operation, stope leaching requires hydrologic site characterization and control of leaching solutions. Several tracer tests, using sodium chloride (NaCl) in various concentrations, were conducted by the U. S. Bureau of Mines (USBM) in an underground experimental stope to simulate a leaching environment. The tests were conducted in fractured crystalline rock that was partially saturated. As tests progressed, the surrounding fractures became more saturated. A predominant flow direction away from the stope was found during testing. Testing procedures, preliminary results, and remediation ideas based on field observations are presented in this paper.

Jan 1, 1995

By Edward J. Harvey

Joplin, one of the most famous zinc mining camps of a bygone era, is today experiencing a healthy growth in manufacturing enterprises. Manufacturing requires water, and knowledge of its availability and quality often is the main factor in location of industry. For this reason in January 1964, on the suggestion of the former State Geologist, Dr. Thomas R. Beveridge, a study of the water resources of the Joplin District was undertaken as a cooperative effort of the Missouri Geological Survey and Water Resources now under the direction of Dr. William C. Hayes and the U. S. Geological Survey. The project area is in southwestern Missouri on the Springfield Plateau and is bordered on the west and north by the Osage Plains of Kansas and Western Missouri, (fig. l). Upland altitudes rise from 900 feet above sea level in the west to 1400 feet in the east. The countryside is rolling to moderately hilly and much is excellent farmland.

Jan 1, 1965

By K. S. Radcliffe

Results are presented for the first phase of an experimental program to study the feasibility of using acoustic velocity for predicting the state of stress in a rock mass. Compressional wave velocities were determined axially in cylindrical samples during uniaxial compression for several rock types conditioned in dry and water-saturated environments. Results indicate that in rocks containing compressible voids or cracks, substantial velocity change occurs with the application of stress in the lower (below 100 MPa) stress regime. The effect norm- ally is nonlinear, however, and diminishes to asymptotic values when cracks or voids become closed or with saturation. Empirical prediction equations were derived for each rock type by linear and nonlinear regression analyses, and correlation coefficients were calculated to determine the equations that best fit the stress- velocity data. The operational range for predicting stress using compressional-wave velocity appears to be within the range of vertical stress expected in most shallow to intermediate depth mining operations (less than 1,000 m). Based on the experimental results to date and theoretical considerations, it appears that the technology can be advanced to predict in situ stress based on acoustic P-wave velocity determinations in most mining situations.

Jan 1, 1986

Fine coal is substantially more costly to process than coarse coal because of technical difficulties associated with separating fine particles and removing process water from both clean coal and refuse. Therefore, companies are often forced to discard coal fines to waste impoundments. According to a recent report published by National Research Council, the U.S. coal industry is discarding 70-90 million tons of coal fines annually to 713 active impoundments, most of which are located in Central Appalachia. On October 11, 2000, a 72-acre impoundment near Inez, Kentucky, accidentally released 250 million gallons of coal slurry into nearby underground mines, creeks, rivers, and schoolyards, thereby creating serious environ-mental concerns. Fortunately, recent advances in separation technologies make it possible to recover fine coal more efficiently from existing coal preparation plants and from waste streams previously discarded to impoundments. The availability of these new technologies allows companies to increase profitability and minimize environmental risks, which are conducive for achieving sustainable mining.

Jan 1, 2003

By C. Perea, O. Restrepo, C. Ihle, H. Estay

In this study, research on the use of monosodium glutamate for copper leaching, with emphasis on the thermodynamics and oxidant characteristics, is presented. Copper dissolution was conducted following a hydrometallurgical route, using monosodium glutamate in alkaline solutions. The effect of oxidizing agents such as hydrogen peroxide (H2O2) and potassium permanganate (KMnO4), and the efficiency of copper leaching with glutamate compared with glycine have been studied. Results, obtained at room temperature, showed 92% recovery of copper using 0.03 M hydrogen peroxide, 0.5 M monosodium glutamate at a pH of 9.44.

Mar 2, 2022

By M. Deniz Turan, HASAN NIZAMOGLU, MÜCEVHER TURAN, RAMAZAN ORHAN

Tailings, or flotation waste, formed during copper production may be considered in the class of valuable wastes because of the amount of copper they contain. With the decreasing grade values of copper ores, the utilization of wastes like tailings that carry certain amounts of copper as secondary sources has become a necessity in both the economic and environmental senses. This study was carried out with the aim of using ammonium derivatives for the recovery of copper from tailings waste produced during copper production and utilizing their complex formation characteristics. In the conditions of six hours of leaching at 30 °C in the presence of 22.5 percent ammonium hydroxide and 100 g/L ammonium persulfate, 91.47 percent of the copper was transferred into the solution, while iron was not transferred, indicating that copper can be selectively recovered from tailings.

By Hasan Nizamoğlu, M. Deniz Turan, MÜCEVHER TURAN, RAMAZAN ORHAN

Tailings (flotation waste) that is formed during copper production may be considered in the class of valuable wastes due to the amount of copper it contains. Owing to the decreasing grade values in copper ores, utilization of wastes such as tailings that carry certain amounts of copper as secondary sources has become a necessity in both the economic and environmental sense. This study investigated the usage conditions of five different ammonia salts as leaching reactants for the purpose of selective extraction of copper from tailings. For this purpose, the effects of parameters such as leaching temperature and leaching time were examined at different concentrations of ammonium hydroxide, ammonium carbonate, ammonium nitrate, ammonium chloride, and ammonium persulfate. The copper extraction efficiency in the case of using the aforementioned salts by themselves were listed as (NH4)2CO3 (73%) > (NH4)2S2O8 (69%) > NH4OH (64%) > NH4Cl (42%) > NH4NO3 (40%). The highest copper extraction efficiency was obtained in the leaching process that was conducted with the solutions obtained by mixing ammonia salts in the best conditions. Accordingly, as a result of 6 h of leaching at 30 °C in the presence of 22.5% NH4OH and 100 g/L (NH4)2S2O8, 91.47%of the copper was transferred into the

Jun 3, 2020

By H. R. Hammond

The situation of The Consolidated Mining and Smelting Company of Canada Limited, or Cominco, may be somewhat unique in that the Company is not only a manufacturer of ammonium nitrate, but as a mining company is a major user of its own product. This situation has resulted in highly successful application of ammonium nitrate-oil explosives. Several noteworthy techniques have been developed and others have been improved. Use of this material in the mining industry has led ammonium nitrate producers to adopt the term nitro-carbo-nitrate or INN for ammonium nitrate-oil blends. A small blending plant at Cominco's largest mining property, the Sullivan Mine, at Kimberley, B.C., is producing more than 80% of all the explosive used at the Sullivan, and is supplying two other Cominco mines. Application has required intensive research to determine the best forms of ammonium nitrate for use in small holes drilled for development and long-hole stoping. It has led not only to experiments to determine the best blending oil, but also to development of loading techniques to the point where NCN is being moved through loading tubes over 700 feet. It has required research into mining practices such as hole arrangement and blasting of development cuts. It has resulted in the development of a special product for secondary breaking. All this has been accompanied by the recognition of the importance of insuring safe practices at every stage.

Jan 1, 1963

By L. C. Atkinson, E. A. Azrag, T. M. Hanna

The results of using a simple analytical solution and a relatively complex numerical model to estimate ground water inflow to an open pit mine are compared. The analytical solution assumes lateral, radial flow to a fully penetrating pit in an idealized confined aquifer, whereas the numerical model simulates fully three-dimensional flow to a partially penetrating pit from a water table aquifer. The latter is a more realistic simulation of the problem, but the former method is significantly easier to use. Comparison of the results obtained with the two methods for some typical hydrogeologic conditions encountered in mining yields ratios between them in the range of 0.2 to 0.6. These values can be used as a coefficient in the Pit Flow analytical solution to produce reasonable estimates of in-flow even when there are significant differences from the idealized conditions implicit in its application.

Jan 1, 1995

By T. M. Hanna

The results of using a simple analytical solution and a relatively complex numerical model to estimate ground-water inflow to an open pit mine are compared. The analytical solution assumes lateral, radial flow to a fully penetrating pit in an idealized confined aquifer, whereas the numerical model simulates fully three-dimensional flow to a partially penetrating pit from a water table aquifer. The latter is obviously a more realistic simulation of the problem, but the former method is significantly easier to use, Comparison of the results obtained with the two methods for some typical hydrogeologic conditions encountered in mining yields ratios between them in the range of 0.15 to 0.60. These values can be used as a coefficient in the Pit Flow analytical solution to produce reasonable estimates of in-flow even when there are significant differences from the idealized conditions implicit in its application.

Jan 1, 1992

By Wendell R. Peters

Shallow underground voids resulting from early coal mining and other resource recovery activities over the past several decades are now being recognized as a significant cause of ground subsidence problems. Uncertain knowledge of abandoned coal mines also imposes potential hazards in current mining operations since water inundation or the release of methane gas is a serious hazard when mine excavation operations break into an abandoned mine. Requirements for detecting and mapping subversive man-made tunnels in previous work has led to the development of a surface- operated automatic earth resistivity survey system and associated computer data processing system for military applications. Field demonstration tests of this system have resulted in successful detection of tunnels at depth-to- diameter ratios greater than ten to one. Under the sponsorship of the Bureau of Mines, a similar high-resolution earth resistivity system was designed and constructed for use as a potential means of detecting coal mine workings. The hardware and software aspects of the new system are described together with applications of the method to the survey and mapping of abandoned coal mine workings. Field tests are presented showing the detection of both air-filled and water-filled mine workings.

Jan 1, 1981