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By D. M. Muir, C. Cao

Many gold ores have copper mineralisation which presents problems in a carbon-in-pulp operation. Various types of copper-gold ores and ways of tackling the problem are discussed. In some cases copper and gold can be upgraded to a concentrate by flotation; otherwise, copper or gold can be selectively leached. When both copper and gold cyanide are present in solution, it is possible to minimise copper loading onto carbon or to selectively strip the copper from the carbon. Alternative leach solutions like thiourea and bromine are discussed and results obtained with the ammonia/cyanide system are presented in the light of our present understanding of the chemistry involved.

Jan 1, 1989

By James L. Noble

A small placer operation can be defined as one with a throughput capacity of 250 cubic yards an hour or less. The success of small placer operations after the values have been established, depend entirely on having the proper design. There are various types of placer deposits including marine, beach, desert, stream, bench, underground and even frozen placers. Each is unique and requires special considerations. Size distribution of alluvial placer ore varies from sand to large boulders. When boulders occur, they can become a problem to all types of excavating to a greater or lesser degree. Clay content and cementing are common in placer deposits. Some clay disperses easily in water while others, if not handled properly, will form clay balls that pick up gold and carry it to tailings. Overburden, depth of bedrock, vegetation, and ground and surface water must all be considered when designing a plant. Any equipment chosen should be capable of processing large volumes of material at a high efficiency. There are usually five steps to processing placer gravels, as follows:

Jan 1, 1992

By J. M. Mutmansky

This paper outlines the results of a study of the opinions of practicing engineers concerning the value of environmental engineering courses in a mining engineering curriculum. One hundred engineers with significant experience in mining-related engineering work were carefully chosen. Of the 67 responses, about half were from mining engineers, and the other half were from environmental engineers. In this paper, the results of the survey are outlined. The number and type of courses recommended by the respondents are summarized as well as the specific topics recommended for inclusion in a mining engineering curriculum. The survey form also asked for the stages in the mine life when environmental experts were needed and the percentage of environmental engineering performed by outside experts for many mining-related environmental tasks. The results of this line of questions are provided. Finally, the paper offers a comparison of the results for environmental engineers and mining engineers and analyzes the differences.

Jan 1, 2003

By Jack W. Murphy, Kent J. McGrew, Rudolph H. Jacobson

Introduction Maximization of profit consistent with environmental protection is the principal goal of new applications development for any conventional or in-situ mining technique. Efficient evaluation of all the parameters that contribute to mining costs and production hinges on proper design and evaluation of testing programs and data. The program discussed herein utilizes several field and laboratory procedures to estimate ore deposit characteristics and optimize lixiviant compositions. The ore characteristics and lixiviant compositions are then used in a long path leaching test (stream tube test). The stream tube test data are analyzed by mathematical models with computer assistance to predict such well-field rate parameters as target metal production, lixiviant consumption, and restoration. When these predicted rates are combined with market values for target metals, capital expenditures, prices of lixiviant chemicals, and other economic variables such as labor costs, power rates, licensing fees, and others, an assessment of the relative feasibility of various proposed mining plans is possible. The flowsheet in Figure 1 illustrates this process.

Jan 1, 1984

By John Waggoner, Steve Klein, John Townsend, Jay Arabshahi

The Riverside Badlands Tunnel is a 13 km (8 mile) long segment of the Inland Feeder Project. This 3.65 m (12 ft) finished diameter water tunnel presented many challenges that had to be overcome to take the project from concept to reality, not the least of which were the diverse ground conditions. Construction of the tunnel was carried out by a single tunnel boring machine (TBM) in one tunnel drive. The project is considered a success due to the accurate baseline established for the ground conditions; the approaches used to mitigate adverse conditions; and the appropriate use of TBM excavation methods, which achieved rapid advance rates despite the challenging ground conditions.

Jan 1, 2003

By Mary B. Ansari

The literature of mine ventilation is very diverse in nature, widely interdisciplinary, and extremely international in scope. Important references are found in indexes, abstracts, government documents, technical reports, journals, conference and symposia proceedings, and monographs. In this decade computer searches of the literature have greatly aided researchers in finding needed items. There is, however, no convenient summary of recent English language literature in coal and non-coal mine ventilation. This paper attempts to fill that gap in the literature. Because of the worldwide provenance of the subject and the attendant publication deluge, this paper covers only current English language publications on ventilation. The writers have examined the field's English language abstracts, indexes, bibliographies, periodicals, technical reports, books, and symposia and conference, proceedings. The survey also considers the field's most important bibliographic data bases. It should be noted that addresses for many of the literature sources listed in the paper are given in the section on literature and data base information sources.

Jan 1, 1980

By John M. Wootten

The development of new coal markets is -t upon the ability to utilize coal in an environmentally acceptable and economically viable fashion. Foremost in the concerns about coal utilization is the impact its combustion has on air pollution. Concerns over environmental issues, such as acid rain, are currently one of the major impediments to the development of new coal markets. The Department of Energy and the Synthetic Fuels Corporation are addressing certain aspects of the development of new technologies for the utilization of coal. However, at the present time, there is a void in the new technology development process. That void is the step from proof- of-concept to commercial demonstration. Congress has established the Clean Coal Technology Fund at a level of $750 million to fill this void. The Department of Energy, in a solicitation of interest, received over 175 proposals for commercial demonstrations of clean coal technologies. A review of these solicitations indicates that $1.2 billion worth of research could be accomplished with a federal cost sharing of $425 million or 35 percent of the total. Industry has indicated, through this response, its willingness to invest its limited funds on projects it feels have the greatest potential for the clean use of coal. What must now occur is that Congress must appropriate the monies from the fund to initiate the commercialization of these clean coal techno1ogies.

Jan 1, 1986

By T. W. H. Parker, S. B. Sadleir

ABSTRACT A comprehensive program of air flush core and reverse circulation drilling, trial mining and beneficiation test work was carried out in 1980-1982 to re-assess the potential of the Mitchell Plateau bauxite deposit. The results generally confirm previous work by Amax Corporation. The bauxite is a medium available alumina and reactive silica deposit which responds well to wet screen beneficiation. High grade pockets have developed locally, with the potential for refractory grade extraction. A major feasibility study of the Mitchell Plateau bauxite deposit was completed in 1983. Due to the unexpected severity of the downturn in the alumina market, development of the project has been deferred.

Jan 1, 1984

The US Geological Survey (USGS) held a one-day workshop at its Denver, CO facility to inform the public of the status of its National Mapping Program. In addition, the agency wanted to obtain information from topographic map users on what their needs are. The agency wants to know what the topographic map user wants. The USGS faces the challenge of keeping up with the changing needs of the nation. In the last few years, the agency has changed dramatically to meet these needs. For example, the "new" USGS incorporates mineral-information specialists from the former US Bureau of Mines and also uses the expertise of former National Biological Service employees. These areas complement the agency's traditional strengths in mapping, geology and water re- sources. The stated mission of the USGS's National Mapping Division is to "meet the nation's need for basic geospatial data, ensuring access to and advancing the application of these data and other related ears science information f& users worldwide." To accomplish this goal, the USGS publishes topographic maps, including shaded-relief editions of areas of special interest (state maps and national parks); photo image maps; satellite image maps; geologic maps and hydrologic maps. The geologic maps include geologic quadrangle maps, oil and gas investigation maps and charts, and coal investigations maps. The familiar 7.5-minute series topographic maps are the most widely used. The 7.5-minute- (1:24,000-scale-) format mapping was begun in 1935.

Jan 1, 1998

By Nolan B. Aughenbaugh

Zoning and environmental restrictions on land usage now make open- pit quarrying more and more difficult, especially near urban areas. One option for quarry operators is to go underground for mineral production. While underground-mining costs are higher than those for open-cut work, there are several compensating advantages. In many cases it is possible to produce the same material underground without affecting land values, and the surface is preserved for industrial, residential, or agricultural purposes. Proper planning can yield underground sites which have great potential value for industrial plants, warehouses, or other business uses. It is essential to plan underground mineral extraction using a three-dimensional modular-room architectural concept to fully exploit secondary space utilization. Prior to the start of underground mining an operator must make a careful geological engineering study to deter- mine the suitability of the deposit and must prepare a plan for safe and economical mining for the purpose of converting to secondary usage.

Jan 1, 1974

By Glenn L. Krum

Inflation has received much attention due to its effect on capital budgeting, associated cost overruns, and declining real profits. This study focuses on the effects of inflation on the evaluation of a mining investment and the estimation of a mining project's revenues. The study indicates that the best method for estimating future returns is the fore- cast dollar scheme. In this scheme, the metal price was held constant, and the operating costs were "inflated" along a historical regression line. The conclusion was reached by comparing the "actual" performance of a 3000 tpd (tonnes per day) lead mine model with 'its estimated performance during four time periods (1950-1960, 1955-1965, 1960-1970, 1965-1975). The individual data files for each time period and estimating method (6 files by 4 time periods) were pro- cessed by a suite of cash flow computational and investment analysis sub- routines. The analysis presumed that the mine was part of a large corporation which could utilize the expensed, development and exploration costs and any investment tax credits, in the year that they were incurred.

Jan 1, 1979

By Salama

In the conventional approach, the separator feed incremental masses are assumed to be concentrated at the midpoints of the density or size intervals and subjected to a model partition function. The resulting separation predictions would change if the locations of the incremental masses were changed. As a result. the predicted results depend on the choice of locations where the feed incremental masses are concentrated in the density or size intervals. A technique that utilizes the cumulative-mass-distribution of the circuit feed and the derivative of the partition (separation) function relative to density or size variables is proposed. The proposed technique eliminates the dependency of the predictions on choice of where the feed incremental masses are concentrated within the density or size intervals. Since the proposed technique is based on the cumulative masses at the upper limits of the density or size intervals, the technique produces a single prediction whereas the existing techniques produce predictions that depend on where the incremental masses are concentrated. In fact, it has been demonstrated that the existing conventional technique, in which the incremental masses are concentrated at the midpoints of the density or size intervals, is a first-order approximation of the technique proposed.

Jan 1, 2002

By J. M. Barker

Formation of commodity agreements depends mainly on the economic instability and associated mitigation measures inherent in the economic conflict between more developed and less developed nations. Five types of possible agreements exist: futures market, buffer stock, restrictive agreement, multilateral contract, and compensatory finance. Lack of market separation between sulfur consumers and producers coupled with large world production and highly concentrated export production in theory suggest a restrictive agreement as most likely. In practice, stockpiling of sulfur, an informal buffer stock, as done in Canada and perhaps the Middle East, has been the main sulfur price-supporting mechanism in the past two decades. No commodity agreements involving sulfur now exist except for multilateral contracts. Sulfur agreements apparently have existed rarely, if at all, in the past. Law (1975) refers to sulfur as one of a group of commodities where "there have been additional control efforts of various types." Clearly, sulfur was a candidate, at least conceptually in the past, for some form of commodity agreement. The following discussion centers on the world sulfur market from 1976 to 1985 in this context.

Jan 1, 1987

By Ken A. Pfaff, Ray Daigh

This paper will discuss state-of-the-art applications of GPS automation in mobile conveying systems. Robotic mobile conveying systems increase profitability, optimize stacking and reclaiming operations, and control complex interfaces more accurately than other systems. We will also discuss the application process in machine-to-machine coordination, selection of the appropriate GPS system, and Ethernet considerations. As the leading supplier of GPS-controlled mobile conveying systems, we'll draw on our experience at Morenci, Radomiro Tomic, Zaldivar, El Abra (Figure 1), and El Tesoro mines in the US and South America to demonstrate system reliability and the lessons we've learned through analysis of these projects.

Jan 1, 2002

By J. Bigu

A theoretical radiation mine model, suitable for underground uranium nines, has been investigated. In this model, the rate of ventilation and/or the radon (thoron) gas emanation from mine walls are time-dependent. Several cases of practical interest have been investigated including sinusoidal, linear, exponential, stepwise, or a combination of two or more of the above. Analytical solutions were obtained for the time-dependent radon (thoron) gas emanation rate. However, because of the extreme analytical complexity of the solutions corresponding to the time-dependent ventilation rate case, numerical solutions were found using a special Runge-Kutta procedure and the Hamming's modified predictor-corrector method for the solution of linear initial-value problems. The mine model makes provisions for losses of radioactivity, other than by ventilation and radioactive decay, by, say, plate-out on mine walls, and by other mechanisms. Radioactivity data, i.e., radon, thoron, and their progeny. obtained with the above mine model for a number of ventilation and emanation conditions, are presented. Experimental data obtained in an inactive stope of an underground uranium mine for a time-dependent air flow case are shown. Air flow conditions (ventilation rate) were determined by tracer gas techniques using SF6.

Jan 1, 1987

By George E. Niewiadomski

The exposure of miners to radon gas and its airborne daughter products is a serious health problem which has long been recognized in the uranium mining industry. The association of high exposure to alpha particle emitters with incidence of lung cancer is well established. There continues to be a pressing need to reduce and eventually eliminate the high incidence of occupational lung cancer among uranium miners through the development of new and improved measurement and control technologies. This paper highlights the current efforts of the Bureau of Mines radiation hazards research program. It is aimed at obtaining a fundamental understanding of the behavior and transport of radon and radon daughters, developing more accurate and reliable instruments and measurement methods and developing cost-effective control techniques. Also discussed are the most recent accomplishments and the future research plans of the program.

Jan 1, 1981

By D. R. Maneval

The vast coal resources of North Slope, Alaska, can be expected to attract substantial interest because the nearly flat-lying coal beds of the coastal plain are specially amenable to surface mining. Mining on a scale large enough to justify coal development in this area could have severe environmental effects. The mitigation would be uncertain because large-scale coal mining and reclamation operations have not been carried out in the arctic. The deficiency of the scientific data base is another factor that requires consideration if coal mining has to develop in accordance with the objectives of PL 95-87. The objective of this paper is to establish the inter-relationship between the problems due to permafrost and factors in reclamation of post-mining land in order to find ways to transform nature in a rational and purposeful manner and to suggest specific reclamation approaches that may be appropriate in this region.

Jan 1, 1987

By T. Ko, K. N. Han, C. S. Park, N. S. Kim, C. Yoon, H. Yoon

Quantitative analysis of Platinum Group Metals from ore samples and industrial materials using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), Atomic Absorption Spectrometer(AAS), and X-ray Fluorescence (XRF) techniques was conducted and the performance of various techniques was compared. The effects of different matrices in the sample materials were compared and discussed for each analytical technique. The ICP-AES technique exhibited better accuracy than AAS but showed limitations in its application due to strong spectral interference in the presence of common matrix elements such as iron. The ICP-MS showed the lowest detection limit and less spectral interferences than the previous two techniques. The XRF technique was also applied to examine the total amount of PGM from industrial materials. Results from each analytical method on various sources were presented and discussed.

Jan 1, 2003

By Alva L. Kuestemeyer, Randall J. Scott

INTRODUCTION Pincock, Allen & Bolt, Inc. (PAH) has developed a series of cost models for Western U.S. Gold Mines. The models indicate the economic potential of developing gold properties at various production rates and ore grades. Various combinations of mining and processing methods are also analyzed. The conclusions shown in this paper are taken from PAH's 600 page study titled, "Capital and Operating Cost Models for Western U.S. Gold Mines." PAH decided to develop the cost manual as a result of our perception of the industry's need for such a document. It was our impression that exploration development decisions were being made on the basis of limited economic information. PAH has compiled a substantial database on unit cost information. That database and the engineering capabilities of the firm allowed us to develop a reasonably detailed analysis of capital and operating costs and overall development economics. The study has developed a series of algorithms for underground and open pit mining, processing, G&A, and infrastructure costs. The capital and operating cost data served as a basis for performing after tax discounted cash flow analysis for the various development alternatives. For the base case scenarios, a 15% DCFROR was assumed and the required ore grade was back calculated using the computer. The ore grade versus production rate graphs summarize the economics of developing gold projects in the Western U.S.

Jan 1, 1987

By R. L. Wiegel, G. R. Oswald

The processors of Florida phosphate rock face constraints similar to those of other mineral operations--leaner ore, more complex treatment schemes and a product which sells for a penny a pound. IMC Fertilizer is a dominant producer in this market with its current operation of five processing plants. An emphasis by their management in maintaining and improving plant performance has continued unabated for some 15 years. This has resulted in a commitment to the importance of routine automatic sampling of product and in process streams, the generation of reliable assay and size distribution data, the accurate measurement of process flows, and the computerized "rendering" of this information into weekly and monthly material balances which provide consistent measures of process performance. In addition, there has been a parallel program to monitor and improve the performance of flotation reagents and to evaluate process modifications or changes in equipment. This paper will describe the evaluation techniques that have evolved over this period and indicate how the historical data base is used to identify plant problems early and help in their solution.

Jan 1, 1991