Search Documents

By J. M. Mutmansky

The SIMAN (SIMulation ANalysis) computer language is a general-purpose, discrete-continuous simulation language for modeling a variety of multi-component systems. The language has been described by its author in a textbook (Pegden, 1985) and in a paper (Pegden, 1986) and is available in a mainframe version, a minicomputer version and a microcomputer version. The language was designed for and has been extensively used for modeling manufacturing systems but possesses many features that are advantageous in the modeling of mining materials handling systems. Consequently, the authors have applied the language to the simulation of an open pit shovel/truck operation to test its usefulness for simulating mine materials handling systems. This paper presents a short background on simulation languages, the capabilities and modeling framework of the SIMAN language, a description of the application of SIMAN to a shovel-track operation and some results and conclusions on the use of the language for mining materials handling systems.

Jan 1, 1988

? World industrialization, increased urbanization, and population growth are driving a sustained demand for minerals, metals and coal. Energy demand is expected to increase significantly in the coming decades - placing even more emphasis on supply, security and environmental impact issues. ? Several countries are taking steps to nationalize their own resources thus safeguarding their supplies and reducing exports of natural resources. ? Understanding the future availability of critical minerals requires a global perspective. It is essential to know where deposits are located, their reserves and resources, the technologies necessary for production, and the costs of producing and transporting the products to consumers. ? As mining companies look to maintain or increase their operating capabilities and increase their mineral resource bases, the search for commodities expands beyond developed terrestrial regions of the world, to include marine resources. (Figure 1) Operating challenges in these locations include finding skilled workers, building infrastructure, improving recovery technologies and practicing sustainable development.

Jan 1, 2011

By L. G. Stolarczyk

In-mine Continuous Wave (CH) Radio Imaging method (RIM) instrumentation has the capability of measuring EM wave propagation constants in layered formations. The RIM method is based upon the fact that seams of coal, trona, potash, quartzite, gilsonite and oil bearing sands form natural waveguides for low loss transmission of electromagnetic (EM) waves. The waveguide forms whenever the seam is bounded by more conducting claystone, mudstone, shale or in the case of oil/gas traps, by a floor of saline water. Disturbances caused by faults, shear zones, paleochannels, sills and dikes significantly alter the propagation constant. The analytical values of the EM wave propagation constants depend on the physical and electrical parameters of the seam. The values are presented in this paper in a graphical form to assist in the interpretation of RIM tomographic images. This paper compares in-mine geologic mapping obtained during mining to tomographic images of the geologic disturbance zones in a Central Utah coal mine.

Jan 1, 1989

By Charles E. Barker

Striking similarities exist between the sediment features and facies formed in some modern heliothermal lakes and the characteristics of some ancient borate depositional environments. Heliothermal lakes are density-stratified with shallow submerged margins surrounding areally restricted deep pool(s) containing a dense brine overlain by a much less dense brine. The reflective brine interface allows solar energy to be trapped in the dense brine which may warn to over 900C. carbonate precipitated from the dense brine is the typical sediment produced in warm deep pool. The strong density stratification reduces turbulence in the lake so clastic sediment is deposited under most of the lake as finely-stratified mudstone-limestone couplets (varves). This depositional process results in clastic lake sediment interfingering with and enclosing a thick evaporite pod(s). Because deep pools can exist at the same time or through geologic time, the evaporite pod(s) may occur sporadically throughout the lacustrine beds.

Jan 1, 1988

By Paul F. Ziemkiewicz, John J. Renton, Thomas Rymer

Any viable model or deterministic formula used to make predictions must follow certain criteria. The standard models and procedures used to project acid load from mining activities operate from a number of assumptions, some of which, although logical, are scientifically oversimplified and, hence, invalid. Highly variable field parameters have lead to highly variable acid projections. Kinetic tests are in themselves misnomers in that no parameters associated with chemical reaction kinetics are ever determined. Sampling error coupled with assumptions made as to the distribution mode of pyritic materials in rock units can lead to highly inaccurate conclusions explaining why acid generation often occurs where none is predicted. The fact that probability theory and paradigms governing luck and chance have not been incorporated into the science of acid prediction undermines any credence placed on such projections. To date, with few exceptions, the acid prediction is logically closer to a game of chance than practical science.

Jan 1, 1991

By Wendi H. Cooksey

This paper examines two comminution circuits on a hypo­thetical gold ore deposit with both small-scale (1,000 short tons per day) and large-scale (35,000 short tons per day) production rates. The most appropriate circuit is dependent on the highest economic performance with a combination of crushing and grinding equipment to achieve the desired product size. The selected circuit is dependent on costs associated with project cri­teria, equipment selection and ore characteristics. Factors influ­encing the selection of the comminution circuit require system­atic evaluation to optimize plant performance and maximize eco­nomic return. The small-scale circuit economics responded best to three-stage crushing followed by a single-stage ball mill. The large-scale plant favors a primary crusher followed by SAG milling and ball milling. The conclusions from this paper indi­cate that each project must be evaluated separately to determine the most economic means of reducing the size of the ore.

Jan 1, 1998

By Victor F. Hollister

The Society for Mining, Metallurgy, and Exploration has compiled a number of exploration discovery case histories. This section in Volume 3 of the series describes the case histories of deposits found in layered rocks. Metallic and nonmetallic ore deposits described in this section include diverse minerals such as copper-nickel sulfides and carbonate-controlled base metals. Other case history compilations include epithermal precious metal deposits and porphyry systems. The importance of ores in layered rocks justifies their inclusion in a case history compilation. Mineral deposits occurring in layered rocks form an economically important class of ores. For example, most sulfide nickel ores are mined from basic layered intrusive rocks. Although the geologic setting is completely different from economic nickel sulfide concentrations, most barite produced also comes from stratiform and strata-bound ores. Zinc and lead ores importantly occur in beds in carbonate host rocks. Gold and other heavy minerals are concentrated in placer deposits. Indeed, the world's largest gold deposit, the Witwatersrand, is a fossil placer.

Jan 1, 1991

By F. W. DeVries, J. Brent Hiskey

The search for noncyanide lixiviants for treating gold and silver ores and concentrates is not a new endeavor. However, in recent years, the overall activity to seek a less environmentally controversial reagent than cyanide has occasioned considerable developmental work. While the elegant economy and simplicity of cyanide, because of its selectivity and the ease of recovering gold and silver from the cyanide complexes, is well recognized, two failings have justified the search for alternates: increasing concerns and costs to assure avoidance of environmental damage from cyaniferous liquids and solids, and the need to simplify recovery of gold and silver from refractory ores. Generally, process development work to date on the alternate reagents has lacl<::ed environmental focus ( Hiskey and Devries, 1992). This paper covers briefly the chemistry of various alternates to cyanide and reviews their environmental implications. In each case, environmental overtones are reviewed following the chemistry. For ease of follow-up, the authors have listed sources of information in detail. Alternates examined include:

Jan 1, 1992

By J. A. Meech, C. A. Harris

Expert Systems are being used in the Mineral Industry with ever­increasing frequency. A major advantage of these systems over conventional computer programs is that the knowledge and intelligence of human experts can be captured directly onto a computer for transfer to novices or other lesser experts. These programs allow rapid construction of process models that are not well-understood in fundamental terms, but for which good operational reasoning exists. In addition, user-friendly access to "high-tech" knowledge can be provided to unsophisticated personnel who otherwise might be turned off by unintelligible jargon. As such, these systems can be important training tools for new operators. This paper describes the features of Expert Systems that relate to gold processing plants. Applications include grinding circuit control, supervisory control of reagent addition and pulp density, monitoring and control of CIP/CIL carbon inventories and the operation of carbon stripping and regeneration facilities. A consultative Expert System is described that provides advice on laboratory cyanidation testwork

Jan 1, 1992

By P Simpson, P Bundo

The Eureka Mine is situated in the Guruve district of Zimbabwe, some 150 km north of Harare. The mine was first worked in 1895 and until recently was operated as a typical Zimbabwean "smallworking" with a single owner­operator and small labour force mining at up to 50m depth and processing 50 tonnes per day of ore via grind, gravity recovery and CIP. The gravity circuit comprised a Knelson 12" Centre discharge Concentrator from which a significant but variable portion of production was recovered. In 1996 exploration was commenced by Delta Gold Zimbabwe (Pvt) Ltd (DGZ), a wholly owned subsidiary of Delta Gold NL of Australia, with the aim of testing mineralisation and establishing a large-scale open pit operation. A feasibility study was completed in April 1998. Construction began in August 1998 and first gold was poured in June 1999. The mine is designed to produce 65 000 oz/annum of gold from 1.5 million tonnes of opencast ore grading 2 git Au.

Jan 1, 2000

By Antonio Dominguez-Perez, Annette Dickmann, Roy Norcross, Andreas Rubo, Stephen Gos

With increasing cost pressure in the production costs of gold, there have been great efforts made to reduce the gold production costs as much as possible and a great deal of effort and lateral thinking is required to maintain a cost effective gold production facility. In a difficult economic environment, there is always the danger of saving in the wrong place. Just like it can be fatal to cut down on innovative research and development for long-term existence and sustainability in most industries, savings in safety and visionary planning of regulations expected in the future can become very costly on the long run, if preventative measures are not taken, observed or ignored. This paper deals with some current topics pertinent to the gold mining industry with regard to the interaction between potential risks, regulations and the costs that arise and can be saved in relation to these. Only an optimal combination of cost effective, safe and technically feasible regulations enable an operation to work economically.

Jan 1, 1999

By Ivan Caetano Machado

Good morning ladies and gentleman. During 1995 Prof. R. P. King (University of Utah Comminution Center) presented 2 papers on new horizons in comminution: "Comminution Research in the United States " was presented at the 1995 Meeting of the National Mining Association, while "Comminution: Meeting the Needs of Fundamental Research in the Mineral Industry" was presented at the 2nd SME Research Forum - 1995. In both papers a very interesting graph named "Energy usage for various comminution schemes" illustrated some poignant issues proposed by Prof. King. We do think that some of Prof. King's ideas might very well serve as "warm-ups" for this Comminution Panel Discussion, which are ultimately the goals to be reached by the 3-minute presentations. Thus, we shall be addressing in the sequence Prof. King's most relevant ideas (as well as introducing his graph), intending therefore show how important creative and state-of-the-art Mill Modeling is, if it is to become a Tool to Effective Cost-Saving Optimization Strategies.

Jan 1, 1996

By Andrew P. W. Briggs, Corale L. Brierley

A considerable economic and technical knowledge base has been amassed with the successful and sustained operation of commercial minerals bioleaching/biooxidation plants to extract copper from chalcocite ore and enhance precious metal recovery from sulfidic refractory ores and concentrates. Economic evaluation ofbio-processing must consider the value of the ore, the sulfide-sulfur requiring oxidation to achieve significant metal recovery, the time required for the biological process and, in the case of precious metal feed-stocks, the down-stream reagent consumption. Of these considerations oxygen requirement for the biologically-catalyzed oxidation of sulfide minerals is the prevailing determinant in the capital and operating costs of aerated, stirred-tank reactors for processing concentrates and bio-heaps for processing ores. Oxygen requirement is dictated by the amount of sulfide-sulfur requiring oxidation to achieve desired metal recovery. The testwork program to evaluate a project for application of biooxidation/bioleaching must be designed to insure that factors critical to economic assessment are fully quantified.

Jan 1, 1997

By G. G. O. O. Uwadiale

Because mineral matter is finely distributed within the matrix, Nigerian Labia coal is nonresponsive to conventional processing techniques. However, testing has shown that Lafia coal can be upgraded by selective oil agglormation. The optimum oil concentration was found to be 10 mL of paraffin per 25 g of coal. A product containing 6% ash and 1.9% sulfur was obtained with a yield of 90%. Optimum results were achieved with a grinding; time of from 2.5 and 3 hrs, which produced a 98% -400 mesh product. However, further grinding wars found to be deleterious to the process. Also, high pH adversely affected concentrate yields. Utilizing kerosene as a bridging liquid, a product containing 4% ash and 0.33% sulfur was achieved at a natural pH of 6.3 with a yield of 85%. At pH 9 and 10, a product containing 4.5% ash was achieved with a yield of >90%.

Jan 1, 1997

By James A. Holtkamp

Environmental regulation in Mexico has matured dramatically and effectively in the last decade. The gap between environmental regulation in the United States and Mexico is rapidly narrowing. From a regulatory perspective, it is no longer necessarily less burdensome to operate in Mexico. Principal laws and regulations Mexico has two principal environmental regulatory systems. The first consists of the laws and regulations governing domestic activities. The second consists of the treaties, agreements and understandings between the United States and Mexico dealing with transboundary pollution and maquiladoras (see Maquiladora Decree, next column). The following are the principal major laws and regulations governing environmental protection in Mexico: General Law: The General Law on Ecological Balance and Protection of the Environment, effective March 1, 1988. Water Regulations: Regulations for the Prevention and Control of Water Pollution, effective May 29, 1973. Environmental Impact Regulations: Regulations of the General Law on Ecological Balance and Protection of the Environment, regarding Environmental Impact, effective June 8, 1988.

Jan 1, 1994

By S. K. Kawatra, T. C. Eisele

The separating efficiency of a flotation column is largely limited by the degree of back mixing of tailings into the froth zone, and the recovery is limited by the degree of short-circuiting of feed to the tailings. Current columns are typically constructed very tall (30 to 40 ft) to limit the effects of back mixing and short-circuiting. These effects can also be reduced in a much shorter column, provided that the flow in the column approaches plug flow. In this work, horizontal baffles were shown to improve the performance of a 6 -ft laboratory-scale flotation column treating a poorly floatable coal. Tests with variations in the baffle positions showed that baffles are needed both above and below the feed inlet to achieve the greatest benefit. Tracer tests with a fluorescent dye in water showed that baffles reduce the amount of feed water entrained in the froth at any given coal recovery.

Jan 1, 1996

By K. Eric Livo

The Front Range Infrastructure Resources Project (FRIRP) of the U.S. Geological Survey (USGS) is currently using Landsat Thematic Mapper? and air- borne-visible-infrared-imaging-spectrometer (AVIRIS) data along with planned thermal-infrared data and interferometry-synthetic-aperture radar (IFSAR) data to assess the industrial-minerals quality and quantity along the Colorado-Wyoming Front Range Urban Corridor and to characterize surrounding areas. Landsat? satellite data show synoptic views of the corridor, which may readily be used to identify potential regions of permissible terrain, such as river drain-ages, pediment surfaces, upturned lithology, and bed- rock exposures, where various types of deposits may occur. Descriptive models of these deposit types are used to define the physical features that need to be recognized and characterized. In the case of Landsat? data, the measured light is either reflected or partly absorbed by surface materials, depending on the wave- length of the light, which allows coarse mineral classifications to be made.

Jan 1, 1999

By David Logan, Sigurdur Finnsson

This project, which is intended to provide effective sewerage services to the Blue Mountains community, is located in the Blue Mountains National Park, about 60 km west of Sydney, Australia. The sewerage scheme consists of about 40 km of tunnels, out of which approximately 22 km have been completed. This paper describes the last major tunnelling operation on this project, the Hazelbrook to Katoomba tunnels. These tunnels, which mainly traverse the Hawkesbury Sandstone formation, are being excavated by a new 3.4 meter diameter Jarva Mk12C TBM. The mucking system consists of a continuous conveyor, which has allowed for some very impressive advance rates. The paper will consist of three main sections; the general geological conditions expected along the tunnel will be described in the first section. The second section will discuss the design and main features of the TBM, back-up system and continuous conveyor. The third section of the paper will describe the operational aspects and various performance data of the machine.

Jan 1, 1995

By Tim O’Neil

Many mining companies try to fight their way up from small operator and exploration company to major producer. Not many companies make it. Cambior Inc., formed in 1986, is one company well on its way to making it as a major operating company. In 1993, Cambior surpassed 15.5 t (500,000 oz) of gold production and began operations at its world class Omai gold mine in Guyana. At the same time, the company has embarked on a program of geographic and minerals diversification. Cambior, a Canadian company, now has interests in eight mines, three development projects and more than 100 exploration properties in North and South America. The company’s goal is to derive 70% of its income from gold and 30% from base metals and other minerals. Cambior’s moderate diversification into base metals gives protection against negative gold price fluctuations. It also balances the typically short term gold mines and the longer term base metal mines.

Jan 1, 1994

By Stanley W. Ivosevic, Mark E. Emerson

Introduction Metals exploration activity is moderately intense in the US despite the 1981-82 recession in the mining industry. Although exploration expenditures are significantly less than the 1981 peak, quality and goal orientation of current exploration are high. Major foreign and domestic mining companies as well as nonmetal companies had been attracted to invest in minerals in the US. Its capital markets, political stability, and open-door policy are attractive for hard mineral explo¬ration, particularly in the West. The approach was to either acquire fully or partially developed ore bodies through merger and acquisition, or to fund large scale exploration programs in search of bulk-tonnage deposits. The acquisition avenue has not proved the panacea envisioned for overcoming lack of substantive mineral development. Nor has the decentralized approach to exploration that was adopted proven cost-effective. The emphasis on gold, to the exclusion of all other commodities, raises questions regarding the direction of exploration in the US for the rest of the 1980s. Overview More than 300 companies are active in metals exploration in the US. These range from established, well-known domestic and foreign corporations to hurriedly incorporated, unknown companies financed by having promoted mineral prospects or occurrences of questionable quality. Junior companies tend to be oriented toward property entrepreneurship, rather than the development of minerals resources. These companies have helped maintain mineral lands from prospect to production by holding blocks of property intact during periods of exploration inactivity. This was done through promotional efforts, even though few properties that attracted major venturers proved to have real merit. Exploration objectives of senior and junior exploration companies currently embrace only a few commodities. Arranged in approximate descending order of priority, these are: precious metals; base metals in monometallic or polymetallic deposits; strategic metals, such as tungsten, tantalum, and tin; unconventional commodities, such as diamonds; ferrous metals; and commodities such as beryl, zeolites, and barite. Prospectors are important in searching for these targets. In the US, where they have been financed by major and junior companies, prospectors have proven a useful and low-cost means of locating gold prospects (e.g. the Alligator Ridge property in Nevada). The tenacity and persistence of independent prospectors have been factors in discovering properties rejected or overlooked by professional geologists (e.g. Lornex mine in British Columbia). This has been realized by the provincial government that grubstakes bona fide prospectors. Exploration interest in commodities has always been cyclic with price. Gold is one of the few metals that has experienced a price increase of such magnitude to warrant attention. The potential for realizing adequate operating margins for the Nevada open-pit "no-see-um" gold deposits is great. The present declining gold price, however, may indicate that this emphasis on gold, to the exclusion of other commodities, is shortsighted. Mining companies have been the last to react to price increases, opening new mines based on unrealistic market expectations. A scenario could develop where plummeting gold prices bring recession to the gold industry, as lately occurred in uranium, molybdenum, and copper. US Exploration Climate The US is attractive for exploration due to its strong mineral po-

Jan 4, 1984