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By Donald S. Clarke

The Umuna epithermal precious metal deposit has provided the target for a simulated rock geochemistry exploration program, directed at bedrock exposed in the drainage system of eastern Misima Island. A geochemical halo to the deposit is readily recognised in the mafic meta-volcanic country rock. This halo is defined by anomalous results for both major (K, Na, Ca, Mg) and minor (Au, As, Sb, Cu, Pb, Zn, Ba, Rb, Sr, Cs, Bi, Ga, S) element geochemistry, extending further than 1km from the deposit. Such halos are sufficiently extensive to provide adequate exploration targets in the search for epithermal mineralisation, complementing mineralogic and secondary media geochemical investigations.

Jan 1, 1989

The sixth annual conference of the Mineral Economics and Management Society (MEMS) was held Feb. 27 through March 1 in Boulder, CO. This year's event was attended by more than 100 academic, industrial, government and other professionals interested in mineral economics and materials management. With about 250 members worldwide, this not-for-profit society seeks to promote scientific and economic analysis of current relevant issues. This year's program was sponsored by Alcan, Bateman Engineering, Cyprus Amax Minerals, J.P Morgan, Knight Piesold LLC and Newmont Gold. The conference's technical program consisted of six sessions. These included "Financial tools for a changing world," "Access to minerals," "Comparing North and South America," "Environmental issues in today's world" and "Transporting minerals." The program was concluded with a panel discussion titled "National minerals policies in Asia." In addition, a student papers session was held, in which students were given the opportunity to compete for a $1,000 award. The following is a brief review of the technical pro¬gram.

Jan 1, 1997

By Nes?e Çelebi

It has never been easy to finance within mining sector. Leasing may be an alternative source of finance for mining investments. Leasing is acquiring the right of usage for an asset for a definite period of time without having the ownership of it. In this study, a model for analyzing the lease financing opportunities for mining investments under risk and suitable for establishing a satisfactory leasing policy for both lessee and lessor is developed. Using the model, it is possible to obtain an expected equilibrium lease amount acceptable by both lessor and lessee and also the expected range of the equilibrium lease amount as a decision tool. First the existing leasing policies are mentioned, then the developed model is described. A case study is presented to illustrate the use of the model in establishing a leasing policy. In conclusion, the usefulness of the model is discussed.

Jan 1, 1992

By Charles F. Herbert

The waves of prospectors who struggled across the wide Alaskan wilderness between 1898 and 19 10 came close to but did not actually find the rich copper/zinc/silver deposits strung out along 161 km ( 100 miles) of felsic schist in the remote Brooks Range of northwestern Alaska. They had heard rumors of gold in the valley of the Kobuk River, so they skirted the Arctic ice pack in the Chukchi Sea and, in a force at least 800 men strong, ascended the Kobuk River in 1898. Twenty-eight placer mining camps were established but only a handful survived for more than a few years. One of the placers that died rapidly was Ruby Creek. A map showing the location of Alaskan mineral deposits is given in Fig. 1. The Ruby Creek miners, disappointed with the scarcity of gold in that creek, followed copper-bearing float to two places where the float was especially plentiful. Pits, a short adit, and a shallow shaft uncovered copper carbonates, bornite, and chalcopyrite in fractured limestone but the remoteness of the district blocked efforts to sell the claims or to raise capital for development. Shortly after 1906, the copper prospects were abandoned and, except for an account published in 1913 by the US Geological Survey, they were forgotten, as were the names of the prospectors.

Jan 1, 1991

By Tom C. Palanglo, Norbert Maerz

Control of crushing and grinding circuits ideally requires continuous particle size measurements on both in- and outgoing streams. Until recently, size distributions could only be obtained by screening methods, which were neither cost effective, frequent enough, nor timely. Input streams are often composed of large fragments, making screening prohibitive. Optical image processing systems, such as the WipFrag System, have been developed to the point that they are an extremely valuable tool to characterize, control, and fine-tune the comminution process. Although accuracy is less than that of screening, measurements are precise enough to detect relatively small changes in size distributions.

Jan 1, 2000

By Robert B. Hopler

For many years the explosives industry was a technological enigma: it was at the 'cutting edge' of some technologies and in the backwaters of others. For example, for at least the past 85 years, the industry routinely measured time to one-millionth of a second for determining the detonation rate of explosives. At the same time, however, formulations were usually hand-written in 'formula books,' such as the alchemists may have done. Also, due to the fact that the equipment had proven to be safe, many of the mixers and packing machines in use until recently were those patented in the 19th century; improving efficiency was not worth the possible risks that might be encountered. In recent years, the wide availability and portability of computers and their adaptation to specialized applications have revolutionized the explosives industry, much as it has many others. With the advent of the water-based emulsions and slurries (water gels), and the necessity to design totally new processing and delivery equipment, the opportunity arose to apply modern techniques to many aspects of the business. Table 1 lists some computer applications currently in use by explosives manufacturers and end users. The use of high-tech production controls, equipment design aids, field measurement devices and other computer applications is so pervasive in the industry today that any brief article such as this must be considered only as a broadbrush overview of the subject.

Jan 1, 1994

By Jaime E. Sepúlveda

Semiautogenous grinding (SAG) operators have been realizing the very significant impact of fresh feed particle size distribution on the mill grinding capacity. In actual practice, this impact may be quite difficult to assess because of the natural process variability that may also involve- concurrently other critical factors such as ore hardness. Recognizing the limitations of the empirical approach, the current publication proposes the use of mathematical models and simulators to explore and assess the net effect of feed particle size only, independent of any other factors. The simulation analysis here reported provides a basis to claim that the size distribution of the particles being ground (simply characterized by a % - 2" or similar measurement) is one of the most relevant controlling variables of the overall mill performance, regardless of the SAG circuit configuration.

Jan 1, 2005

By V. Srajer

Operations research includes the application of systems analysis to mining operations, the acquisition of field data and the creation and verification of computer models of these operations. These activities result in the generation of computerized mine planning tools which have a firm base-in observational facts. The Surface Mining Laboratory of the Canada Centre for Mineral and Energy Technology (CANMET), in Devon, Alberta has been engaged in operations research activities since 1982. The work includes computer simulation of truck/shovel, continuous mining equipment and dragline operations. Other examples include cooperative programs with industry (such as the demonstration and evaluation of an integrated truck management system), the development of a device to measure off-highway truck rolling resistance, and an automated remote data transmission network. The presentation outlines existing and proposed research projects of the Operations Research group.

Jan 1, 1989

By Helen Leung, Colin R. Phillips

The performance of personal alpha dosimeters in mixed radon daughter and thoron daughter atmospheres in Ontario uranium mines is described together with monitoring developments which enable the radon daughter working level to be determined separately. The theoretical bases for continuous and integrated working level measurements based on individual and gross counts are presented in terms of the weighting factor for combining the thoron daughter working level with the radon daughter working level, and in terms of the in-growth time of the air. Implications for the determination of working level in the presence of thoron daughters are discussed.

Jan 1, 1981

By Jane Morrison

Permanent magnets are used in most electromechanical and electronic devices to convert electrical to mechanical energy and vice versa. More than fifty are commonly found in the average American home and car. A new species of permanent magnet composed of iron, neodymium, and boron has recently been developed which combines superior magnetic properties with compact size. The reduced size of the magnets has enabled significant new developments in such areas as robotics and consumer electronic, among others. The objective of the present work is to efficiently and economically separate valuable rare earth materials from the relatively worthless iron constituent in NdFeB magnet scrap. Several magnet producers have expressed interest in the development of such a process and have provided information and scrap samples to aid in research. Scrap is generated in a variety of forms from different stages in the processing stream. Pieces of magnetic and non-magnetic metal as well as sludge and ribbon from jet casting must all be treated. Beneficiation techniques have been studied and size distributions developed for the different scrap types. Slag from the casting process is resistant to crushing and may need to be embrittled first, but all other types are amenable to crushing and ball mill grinding using stainless steel balls and water. Tabling was found to be useful in classification of magnet sludge. Two major techniques for separation of rare earths have been studied:

Jan 1, 1990

By A. I. Kalugin, A. A. Abramov, D. E. Kozlov

As a result of thermodynamic analysis of a mineral-sodium, oleate-water system, flotation and adsorption tests at various pH values, and sodium oleate concentrations, it has been established that due to regularities of phosphate-containing minerals (fluorapatite, hydroxyapatite, carbonatapatite) flotation cannot be explained by the formation of alkali-earth metal oleates on their surface. This paper presents a novel theory that connects optimal conditions for mineral flotation with zero charge of its surface, which can explain the regularity of minerals flotation observed. The quantitative physicochemical flotation models developed based on the theory are suitable for improving industrial processes, conditioning of recycling waters, and application in automatic control systems at the plants. Key words: apatite, oleate, flotation, modeling, control, and regulation.

Jan 1, 1999

By Darryl Amick, Keith A. Prisbrey, Lee E. Plansky

The problem addressed was to develop automated image analysis of metal welds to replace unreliable and costly 100% visual inspection. The objective was to evaluate neural networks combined with features from gray level surfaces. Photomicrographs of the welded seam in Zircaloy-4 channels used in nuclear fuel rod assemblies were examined. The methodology used was to select a set of morphological feature coefficients from Bessel Fourier morphological feature coefficients extracted from digitized photomicrographs. The selected morphological feature coefficients were then used to train a neural network. The approach was verified initially by successfully training a neural network using the known, secondary chemistry of the alloy welds. The results were good. The Bessel Fourier coefficients captured sufficient information from the metallographic images to distinguish weld quality. This approach has the combined advantages of compressing the images through Bessel Fourier coefficients and give the ability to rapidly process large amounts of data using neural networks.

Jan 1, 1993

By Henry P. Ehrlinger III, Latif Khan, John M. Lytle

The primary purpose of this project was to produce and test coal concentrates made from coal preparation plant waste fines for use in a slurry-fed gasifier. Concentrates from several individual waste streams were examined to determine their amenability as feedstock for a slurry-fed, slagging, entrained-flow gasifier. The tests included analyses of the plant feed and product, material balances, and estimates of gasification reactivity and of pumpability. The following preparation plant fines were examined: • fresh rejects produced in a plant processing underground- mined Springfield Coal • fresh rejects produced in a plant processing underground- mined Herrin Coal • fresh rejects produced in a plant processing surface-mined Springfield Coal and Herrin Coal • Five-year old impounded fines rejected during processing of underground mined Herrin Coal. At high coal recoveries the Btu content of the concentrates was greater than the Btu content of the utility product from the plant. The coal recovered from fines was found to be entirely acceptable for gasification and pumping without additives.

Jan 1, 1995

By Leszek W. Lunarzewski, Adam L. Lunarzewski, Raymond C. Pilcher

The Floorgas and Roofgas simulation programs are used to identify strata relaxation zones and their boundaries, to assess active gas sources from coal seams and gas¬bearing rocks and to determine relevant gassiness prediction coefficients for any local longwall. The paper shows that by use of the print-outs from the Floorgas and Roofgas programs the following benefits are achievable: • identification of the shear and gas discharge zone positions in the floor, strata relaxation angles and various gas discharge zone positions in the roof, which are both relevant to local geological and mining conditions • optimisation of cross-measure drainage hole length, location, number and angle of inclination calculation and definition of gas make prediction coefficients such as the release ratio from adjacent coal seams, specific gas emission during longwall extraction and the relationships between gas make, longwall width and coal production levels.

Jan 1, 1995

In the early days of minimal environmental protection awareness and unreasoning economy development pressures, little attention was paid to growing environmental concerns in Fuxin colliery, especially the air pollution problem due to the long term mining activities. In order to determine air quality concentration levels, a new technique for synthetic assessment of ambient air quality by using the extension of matter-element method is proposed in this paper. The air pollutants data such as Sulphur Dioxide (SO2), Carbon Monoxide (CO), Nitrogen Oxides (NOx), Total Suspended Particulates (TSP), Particulate Matter (PM10), and dustfall collected at four different air quality monitoring stations located in four districts of Fuxin colliery is used. The results obtained indicate that TSP, PM10, dustfall and SO2 are the predominant pollutants. Other pollutants such as CO and NOx are also detected in Fuxin colliery. The air pollution comes mainly from industrial emissions, mining activities and the abandoned gangue stockpiles. Compared to those applied to other mathematical assessment methods, it is demonstrated that the extension of matter-element model is quite appropriate for air quality assessment.

Jan 1, 2006

By L. M. Klimov

In recent gears in the coal industry a great deal of attention is attached to the questions of elaborating and introducing the problems of planning and management and, first of all, in the sphere of mine production. The basis for planning of mi- ne production is complexes (sets) of problems for planning the development of mining operations based on different time periods, ensuring the follow-up of changes of mine productive capacities. Complexes of problems for planning, the development of mining operations at existing underground and surface mines within the OASUugol system (Coal Industry-wide Automatic System of Management) are aimed at ma- king decisions close to optimum, i.e. general lay-out of panels, blocks and pillars; transport and ventilation networks; schedules for working out parts of mine take; coordinated mining operations with limited labour and material resources; control of mining operations and ultimately maintaining productive capacities of existing mines at the required level.

Jan 1, 1979

By J. M. Baker

It seems appropriate here to open with a quotation from the great pre-Confucian philosopher Lao-tze: "The softest thing in the world dashes against and overcomes the hardest. There is nothing in the world softer or weaker than water, and yet for attacking things that are firm and strong there is nothing that can take precedence of it." I am happy to report that our system of mining has worked out, with minor modifications, as well or better than was predicted. This, in a period of rising labor and material costs, has been most gratifying. Gilsonite is a solid hydrocarbon which occurs in vertical fissures cutting the sandstone and shale beds of the Uintah formation in south¬eastern Utah. It is found in other parts of the world under similar occurrence but nowhere else is it now being mined commercially. The Gilsonite veins on entering the shale members of the Green¬river formation break into small veinlets separated by shale, These veinlets are not now economical to mine.

Jan 1, 1959

By S. K. Kawatra, H. L. Dilley, W. W. Wen, T. C. Eisele

To improve the sulfur-rejection capability of a coal-cleaning plant, it is first necessary to evaluate the performance of the existing circuit. This information can then be used to decide whether there would be significant benefits from improving the operation and control of the existing circuit, or whether further improvements would require more radical process changes. This paper describes a simple model for evaluating heavy-media separation circuits, and presents a case-study of such an analysis of an operating heavy-media coal cleaning plant. Efficiency curves were calculated and modelled using Lynch's method, and a simplified expression was derived for calculating the Ecart Probability value from the model parameters.

Jan 1, 1995

By C. H. Sampaio

The effectiveness of modem spirals in the processing of fines from Brazilian coals is assessed and discussed. Coals representing the four major coalfields in Brazil have been cleaned in Reichert LD 9 spirals in pilot and industrial plants and performance results are here presented. Normalized distribution curves for all equipment and splitters are presented and were modeled using an empirical model. These data have been compared with those for shaking tables and water-only cyclones (WOC), and it has been observed that, in the size interval investigated, spirals have indeed superior accuracy than WOC and comparative performance to tables. By analyzing experimental as well as simulation results it could be observed that although limited by the poor liberation characteristics of most Brazilian coals, significant ash and sulfur removal could be achieved using spirals.

Jan 1, 1995

By Al Sylvester

The drill-and-shoot excavation of the two underground Pumphouses for the Metropolitan Sanitary District of Greater Chicago's Mainstream Pumping Station is described. The construction sequence involved the concurrent excavation and support of the two 19.2 m (63 feet) wide by 83.6 m (274 feet) long by 29.3 m (96 feet) high caverns. Excavation was interrupted after taking the 6.1 m (20 feet) high top heading in order to cast-in-place a 0.2 m (8 inch) thick by 19.2 m (63 feet) wide concrete arch. The remaining 23.3 m (76 feet) of rock was then excavated in benches below the concrete arch. PROJECT DESCRIPTION Twenty-four kilometers (15 miles) southwest of the city of Chicago, Peter Kiewit Sons' Co., in a joint venture with John F. Shea Co., and Kenny Construction Co., has successfully completed the construction of the Mainstream Pumping Station for the Metropolitan Sanitary District of Greater Chicago. The five year, 169 millon dollar project is a vital component in Chicago's Deep Tunnel and Reservoir Plan in that its function is to lift the sanitary/ storm sewage back up to grade from 107 m (350 feet) below ground, and pump it to the treatment facilities 8 km (5 miles) away.

Jan 1, 1985