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By A B. Christie

REGCHEM is a geochemical database containing stream sediment geochemical analyses compiled from open file mining company exploration reports. The database contains data on over 21 000 samples that have each been analysed for several elements such as gold, silver, arsenic, copper, lead and, zinc.   REGCHEM is supported by GEOEXPL - a custom written computer software application which operates under Microsoft Access. The data can be plotted as maps using a geographic information system (GIS) package called MapInfo, which can incorporate data from other data sets such as mineral deposit sites from the geological resource map database, GERM.

Jan 1, 1994

By Sue W. Wells, James J. Moore, Stephen D. Lynch, R. Hunter White

This paper describes the products and services that Phelps Dodge Corporation desires from solvent extraction reagent suppliers and the partnering relationship that Phelps Dodge wishes to develop with these suppliers. Product topics include: 1) manufacturing concerns, 2) product and process quality control reporting and 3) reagent customizing to meet individual plant needs. Service subjects include distribution, delivery time, emergency re-supply, terms, and tailoring technical support. The partnering relationship discussion reviews mutual benefits, communications, reliability, cross-functional teams for problem solving and developing new opportunities, and long-term commitment.

Jan 1, 1994

The Penetrating Cone Fracture (PCF) technology 1 is a new method of rock excavation developed by Sunburst Excavation, Inc. of Denver, Colorado. PCF is a rock excavation method which employs tensile breakage mechanisms under controlled conditions to enable the continuous excavation of rock?in underground and some surface applications. The technology has developed rapidly over the last two years to the point where it is now being prepared for commercial application in the mining and civil construction industries. The initial commercial application of PCF will be undertaken at the Perseverance Nickel Mine of Western Mining Corporation Limited in Western Australia beginning in May, 1994.

Jan 1, 1994

By Carlos Carnurri

A characterization of mechanical properties of fire refined copper has been done in order to link ductility with oxygen content. The results show four different copper mechanical behaviours as temperature increases, where the oxygen con- tent, as Cu20 segregated, has a deleterious effect on ductility. It is concluded that until 500 ppm oxygen content, the fire refined copper could be rolled without remelting for deoxidation. Also a subsequent cold rolling could be done without intermediate annealing.

Jan 1, 1994

A simulation of a capper concentrate smelter was built with a capacity of 450,000 tons per year. The system's components to simulate were three : a Reverbetory furnace, a Wiente ' s modified converter ( TMC ) and two cranes. The system was classified as dynamic, stochastic and discrete. In the simulation language choice it was concluded that the most advantageous one was GPSS/H. The model verification was done through the interactive Debugger that the language has and the statistical validation was done through the result variables of sane activities, that as a whole characterize the system (charged matte and charged concentrate to the TMC, skimming white metal and skimning slag). The validation was done comparing the simulation results of these variables with the ones obtained for those variables in a specific month in the smelter. The comparison consisted in a difference of means test and in all cases the equality was accepted with a 95% of confidence. The animation tool was PROOF, a general purpose animator, that is used after processing the simulation.

Jan 1, 1994

Geological information is essential for a diversity of public and other purposes, including land use planning, hazard mitigation, and the exploration and sustainable use of natural resources. This is especially important in New Zealand, where the complexity of the geology is due to its position on an active plate boundary - the ultimate cause of earthquakes, mountain building, subsidence and volcanic activity. The geological setting also controls the origin and distribution of New Zealand's varied mineral and energy resources. Providing information about the origin, quality and quantity of mineral resources has long been seen as a key function of national geological organisations such as the Institute of Geological and Nuclear Sciences. Such information is essential for wise land-use decisions under the Resource Management Act. One of the major goals of the Institute is to quickly and effectively disseminate research results to interested users. The most effective and internationally accepted method of presenting geological data is by means of geological maps, which show the distribution of rock types and structural features at the surface. Most countries have ongoing gelogical mapping programmes, and in recent years the need for up-to-date, reliable information has led to a trend to accelerate basic geological mapping (eg US National Geological Mapping Act 1992; Australian National Mapping Accord 1990; Plan 2000 in the UK). Over the last 25 years, the Institute of Geological and Nuclear Sciences and its predecessors (NZ Geological Survey and DSIR Geology and Geophysics) have concentrated on detailed mapping of priority areas selected on the basis of economic and scientific interest. This has included remapping of Nelson-West Coast and Coromandel, regions with high mineral potential, for which 1:63 360 or 1:50 000 maps have been prepared.

Jan 1, 1994

By Bruce W. Cavender

During the last few years, the minerals industry has been confronted by increasingly stringent environmental regulations that are significantly altering the economics of the industry. Heightened media attention, threats of litigation and decreasing support by the general public have exacerbated the industry's difficulties. Regardless of their merit, environmental issues present a serious threat to the continued viability of mining companies. Firms have reacted to these regulations by escalating their environmental activities to meet the new requirements. They have simultaneously adjusted their corporate schedules to reflect the substantially longer time periods required to obtain construction and operating permits and ensure compliance with legal requirements before mine abandonment. Companies have also been forced to adapt to a considerably greater amount of uncertainty and expense associated with the development of mineral projects. This has resulted in a significant erosion of the profitability of some mining companies. Most of the changes in corporate environmental activities have been reactive. Pending regulations present formidable but uncertain technical requirements for compliance, and future regulatory developments are difficult to predict. This problem is aggravated by depressed market prices for many mineral commodities. Past expansions of environmental standards have led to the closure of mines and processing facilities due to economic hardship, as occurred in the smelting segment of the US copper industry in the 1980s (Cro¬zier, 1992).

Jan 1, 1994

By Thompson P, Sharma Y

The paper describes the methodology and results from a study carried out by Telfer Gold Mine to optimise the materials and costs involved in construction of the pad for their dump leach operations. The investigation involved large-scale field testing of five different types of liner and a number of different cushion and drainage layer configurations. The aim was to identify the most cost effective construction methods to allow the final dump height to be increased from 45 in to 60 in without causing significant damage to the liner. The effects of dump height on permeability were also investigated. These methods are described and results presented. The findings indicated that modifications to the existing liner/cushion layer/drainage layer configuration used previously at Telfer would actually reduce overall construction costs rather than increase them despite an increase in overall dump height. Relative construction costs are presented.

Jan 1, 1994

By C. T. Aimone-Martin

Time-domain reflectometry (TDR) laboratory experiments have been conducted using cylindrical salt cores from the Waste Isolation Pilot Project (WIPP). TDR has been used as an instrumentation technique to quantify the type and magnitude of rock mass deformation. Laboratory shear and tensile tests were conducted to calibrate measured deformation versus changes in reflected waveforms. Coaxial cables grouted within rock cores were crimped to produce localized reference defects. The evaluation of waveform characteristics produced during rock deformation experiments shows a good correlation of cable response to both shear and extension of the salt

Jan 1, 1994

By Mike Trovant, Stavros A. Argyropoulos

"A fixed grid numerical model for phase change problems is proposed. The model solves for heat transfer and fluid flow, via the coupled solution of the energy, continuity and momentum equations. In addition, the numerical scheme accounts for temperature varying thermophysical properties and determines the shrinkage profile resulting from phase and density change. Simulations are run to determine the effect of varying model parameters and wall cooling rates on the location and shape of the shrinkage void formation in cylindrical casts. Results are shown for both aluminum and magnesium.IntroductionThe mathematical modeling of phase change processes (be they solidification or melting problems) entails solving for many interrelated phenomena. A comprehensive numerical simulation of the casting of a metal, for example, would have to account for: (a) heat transfer in both the solid and liquid portions of the metal and in the mold, (b) the release of latent heat during phase change, (c) fluid flow behavior in the liquid portion of the metal, (d) temperature induced shrinkage caused by liquid contraction and solidification contraction, and (e) the development of thermal stresses with accompanying shrinkage in the solid portion of the cast and mold. A schematic of the relationships that exist between the coupled equations which govern solidification is shown in Figure 1."

Jan 1, 1994

The rheological behavior of high concentrated coal -water slurry (cws), a new liquid fuel, is an important factor in the preparation, transportation and combustion. The conventional viscosimeters designed for Use with true fluids are not suitable to the measurement of the rheological behavior of cws. So that a special viscosimeter of tube type for cws was designed and set up in .laboratory. Experiments using two kinds of cws from two provinces from P. R. Olfna were conducted. It is found from test results that the experimental cws possess the rheological character of Bingham fluid and there is the existence of the wall effects which causes the measurement errors. In our former paper published the wall effects were discussed III the light of methods of Odroyd and Jastrzerbsiki to make the correction of the experimental results. But a number of tests are necessary to meet the need of determining the slip coefficient. In this paper the models of the wall slip velocity and the thickness of the slip layer of Bingham fluid were proposed III in theoretical approach which were satisfactorily used in the correction of the measured results of the rheological character of cws.

Jan 1, 1994

By M. J. Hrebar

This paper reviews large dozer stripping techniques and presents results of two field studies. The first is a seven-shift study of a contour block stripping operation where a Caterpillar DII is used as the primary stripping equipment. The second is a two-shift study of two Cat DIIs dozing blast cast material ahead of a dragline operation. Surveys and continuous time studies were used to determine production rates and as a basis for forecasting unit stripping costs in both cases.

Jan 1, 1994

By K. L. Bickel

Catalyzed diesel particulate filters (CDPFs) are used for reducing diesel particulate matter (DPM) concentrations in underground mines. The U.S. Bureau of Mines is conducting research on how catalyzed diesel particulate filters perform. Two CDPFs, with two different catalysts, are used on vehicles in two mines. The CDPFs are periodically removed from service and evaluated in the laboratory to determine their DPM collection efficiency, regeneration temperature, and effects on gaseous hydrocarbon (HC) and carbon monoxide (CO) emissions. This report summarizes the results of the laboratory evaluation, and the mines' experience with the CDPFs. Both CDPFs have operated over 2,000 h. One was evaluated after 1,646 h; its collection efficiency at one operating condition was 87.3 pct. After 2,135 h of operation it was removed from service because it was damaged. The second CDPF continues to be used after 2,328 h of service. The laboratory evaluation indicated its collection efficiency decreased after 1,584 h of use and its regeneration temperature increased from 405' C to 420' C. The mines' experiences with the two CDPFs varied. While being used on mine vehicles, both CDPFs became plugged with DPM on a number of occasions because of insufficient regeneration. CDPFs are capable of lowering DPM concentrations in diesel exhaust. They can also lower emissions of CO and HC, depending on the type of catalyst used. In this study, the performance of the CDPFs changed with use. Recommendations are given in this report for proper use of CDPFs in mines.

Jan 1, 1994

By Robert J. Hite, James P. Searls, Sherilyn C. Williams-Stroud

Potash is a generic term that includes potassium chloride, potassium magnesium sulfate, potassium sulfate, potassium nitrate, and sodium-potassium nitrate mixtures. In the ceramics industry, potash is also used to refer to potassium oxide. Potash, primarily in the form of potassium carbonate, was the first industrial mineral produced in the United States, and the first US patent issued was for an apparatus and process developed in 1790 for its production (Paynter, 1990). Prior to the 1860s, potash was primarily sold as an impure form of potassium carbonate produced by burning hard- wood trees and leaching the potassium salts from the ashes. The major early uses of potash include soap and glass making, dyeing fabrics, baking, and saltpeter for gunpowder. In 1859, the development of a purification process to remove the sodium and magnesium chlorides was developed for the carnallite found at Stassfurt, Germany, and mined potash became available. With the appearance of mined potash and the earlier (1840) discovery in Germany by Justus von Liebig that potash was a nutrient for crops, potash started to be used for high valued crops such as cotton and vegetables. The German potash companies quickly developed a manufacturing process for producing potassium sulfate for tobacco fertilization. German potash supplied nearly all American needs until the embargo of the First World War when imports from Germany were interrupted (Bateman, 1918). With the discovery of potash deposits in New Mexico in 1931, the United States became self-sufficient in potash. In 1962, the United States began importing potash from Canada, and two years later domestic apparent consumption began to exceed domestic production. Along with nitrogen and phosphorus, potassium is one of the three essential plant nutrients, the "K" of NPK terminology. As a result, 95% of potash production is used as plant fertilizer. In all plants, inadequate potassium diminishes growth, causes increased disease, stalk and stem breakage, and susceptibility to other stress conditions. Plants take up large quantities of potassium from the soil, and potash fertilization replaces this loss so that each new crop can be grown with the same vigor and productivity as the previous year's crop. The potassium depletion of the soil from growing repeated cotton and tobacco crops is well known in the history of southern agriculture in America. George Washington was known to have studied alternative crops that could be grown on soil that had been depleted by repeated tobacco crops. Most of the remaining 5% of potash consumption is by the chemical industry, as potassium hydroxide to produce soaps and detergents, glass and ceramic products, dyes, explosives, alkaline batteries, and medicines. Potash as chemical is used in oil field drilling mud, the aluminum recycling industry, and the electroplating industry. Additional minor uses for potassium chloride include water softener regeneration, sidewalk deicing, and salt substitution for human consumption. Potash is used in the food industry as potassium phosphate, and in production of glass products as potassium carbonate or nitrate. GEOLOGY Potassium is the seventh most abundant element in the earth's crust and the sixth most abundant element in seawater. It is found in silicate minerals of igneous, metamorphic, and sedimentary rocks and is also a major constituent of many surface and subsurface brines. The majority of world potash resources are found in subsurface bedded salt deposits which yield high grade, large tonnage ore bodies and are amenable to low cost mining and beneficiation. Because of the relatively high solubility of potassium minerals, potash from salt deposits is ideal for use as fertilizers. Some potash production is from evaporation of naturally occurring brines, but the vast majority of current domestic and international production is from bedded salt deposits. Sylvite, carnallite, kainite, and langbeinite are some of the more important potassium minerals (Table 1). Sylvinite, a mixture of KC1 and NaCl is the highest grade potash ore. Carnallite can be considered a potash ore when removal of magnesium chloride is included in the beneficiation, but it can also be considered a contaminant when mining for sylvite. Potassium sulfate and potassium nitrate are typically manufactured products. Potassium sulfate is produced from mined minerals through conversion processes in Italy, Germany, and Carlsbad, NM, and from brines in southern California and at the Great Salt Lake in Utah. Natural deposits of potassium nitrate occur only in small amounts in Chile. The majority of potash-bearing bedded salt deposits are believed to have originated from the evaporation of seawater or mixtures of seawater and other brines in restricted marine basins (Schmalz, 1969). The reflux depositional model for evaporite deposition was first described in the literature in 1888 by Ochsenius. A shallow bar, or sill, across the mouth of a basin lets in a restricted flow of seawater which evaporates into a salt-precipitating brine (Fig. 1). The density of the brine at the distal end increases with increased salinity, sinks to the bottom, and sets up a reflux current of higher density brine back toward the ocean. The sill, which restricts the inflow of seawater, allows inhibited flow of evaporation-concentrated brines back to the ocean. The least soluble salts are precipitated nearer the sill, and the most soluble components come out of solution in the deeper parts of the basin. The result is a lateral facies change in a tabular-shaped deposit that is due to the salinity gradients in the brine (Fig. 2A). The asymmetrical facies distribution of the Paradox Formation (Middle Pennsylvanian) Utah (Hite, 1970), the Prairie Formation (Middle Devonian) in Saskatchewan (Holter, 1972), and the Salado Formation (Upper Permian) in New Mexico (Lowenstein, 1988), might prompt explanation by such a model. Other deposits, such as the Salina Formation (Upper Silurian) in Michigan (Matthews and Egleson, 1974), show a facies distribution that could be described as a bull's eye pattern. Although some small subbasins of high grade sylvite are found near the margins, the potash is generally located in a central part of the basin surrounded by successively less soluble facies (Fig. 2B). The sparse

Jan 1, 1994

The South Mine, property of Broken Hill South Limited, is situated at Broken Hill, NSW, Australia, towards the southern end of the main lode. The leases (MLs 7 and 8) cover a length of 2400 feet along the lode outcrop and the workings extend, at this date, to a depth of 1940 feet below the collar of the original main shaft and to 825 feet below sea level. Mining operations have been continuous for about 58 years and during this period nearly 12.5 million tons of ore have been mined. The monthly tonnage extracted approximates 30 000 tons in normal times.The ore is a mixed sulphide containing galena and marmatite; the gangue minerals are principally calcite, rhodonite, quartz and garnet. A typical assay for a monthly period is 14.4 per cent Ph, 5.6 ozs Ag, and 11.6 per cent Zn. The whole of the ore is concentrated on the property by combined gravity and flotation methods. The lead and zinc concentrates produced are railed to other centres for the extraction of the contained metals.

Jan 1, 1994

By C. L. Barron, M. L. Smith, K. A. Prisbrey

SAG mill throughput is often a bottleneck to increasing plant productivity. Improved size distribution control in the mill feed can be used to increase mill production. This can be accomplished by controlling blast fragmentation as a function of energy input and rock characteristics. Such an approach requires the integration of rock fragmentation and comminution modeling. The optimal mill feed size distribution is determined by adapting a population balance comminution model to a measure of rock hardness or fragility, which is also related to the rock fragmentation that is achieved by blasting. The relationship between the size distribution and fragility of the feed and the mill's product and the critical size in a SAG mill is examined.

Jan 1, 1994

By E. Topuz, C. Patrick

Longwall face-to-face transfers can cost more than $100 per minute in lost production potential and $100,000 for personnel and supplies. Such high costs make extensive planning and control of the transfer process a critical necessity for the economic feasibility of longwall operations. Operations research techniques are used for the analysis and modeling of longwall face-to-face transfers. Transfer data has been collected from companies who operate, over 35%, of the total US longwall faces. Comprehensive sequence networks of existing longwall transfers were developed; simulation was used to generate models of transfers under Carving conditions; and the economic feasibility of tine-cost tradeoffs in the transfer procedure was investigated.

Jan 1, 1994

By L. Xu, R. Bhaskar

While a NIOSH accepted procedure exists for determination of quartz in the respirable dust samples from coal mines, no specific procedure has been defined for quartz determination in bulk samples. In this study, the effect of particle size on the estimation of quartz using the infrared technique was evaluated. Several laboratory tests were performed to determine the dependence of the infrared absorbance peak height on the different sizes of quartz particles. The significant dependence observed between quartz particle size and the measured peak height indicates the potential for erroneous interpretation of the quartz in bulk samples depending on how the samples are prepared. A procedure to reduce the effect of size in the determination of the quartz content is suggested.

Jan 1, 1994

By E. Fidler

A recent headline in the Wall Street Journal declared, "trendy management schemes very often fail." Many of the management techniques addressed in the accompanying article are associated with quality management including reengineering, benchmarking, total quality management, and employee empowerment. The article made the point that executives, employees, and customers who are involved in such programs rate the effectiveness of these programs very low, and the programs often fail. Yet, we all know of companies that have made significant advances in their operations using these same quality management practices. Why do a few succeed while many fail? History has shown that the companies that successfully carry out quality management programs have two things in common: 1) Strong leadership committed to the success of the program. 2) A comprehensive plan for carrying out and maintaining the program. Stated another way -the reason many companies fail is the lack of committed leaders and inadequate planning. It is ironic that the title of the Wall Street Journal article is "The Best Laid Plans."

Jan 1, 1994

By Peter J. Hancock

The pyrometallurgical .processing of non-ferrous, complex materials and wastes will be surveyed. Pyrometallurgy offers the most versatile way of processing a large variety of such materials because of its high temperatures, closely-controlled oxidation potential and the availability of commercially-proven reactor configurations. Some current industrial applications will be reviewed and possible new applications as well as future trends will be outlined.

Jan 1, 1994