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Since 1992 the Grasberg Mine, located in the remote regions of Indonesia, has utilized the Modular Mining System. Over the last several years, major steps have been taken to maximize this productivity enhancement system. These steps include; the Automated Lineup, the Linear Program upgrade, tracking of Mean Time Between Failure, a MEDS system interface, a VMIS system interface, and implementation of the new Graphical Operator Interface Console with Global Positioning, This application of new technology and innovation has lead to improved performance, understanding and reporting, as well as the quality of the Indonesian Engineers. These efforts have contributed 10 Grasberg achieving one of the lowest mining costs in the copper industry.

Jan 1, 1998

By Richard H. Lindgren

I appreciate this opportunity to discuss with you OPIC's new policies designed to assist U.S. minerals companies in developing new sources of minerals overseas. A comparison of recent figures on U.S. investment in mineral exploration, development and production gives results which are remarkable --and disturbing. Through the 1960's the flow of U.S. foreign direct investment in mining and smelting in the developed and less developed countries were nearly equal. However, by 1973, roughly 80% of all exploration expenditures by mining companies was taking place in the developed countries and principally in the U.S., Canada and Australia. Clearly it is to the interests of both the developing countries and the United States to put these figures back in better balance. As you may be aware, the administration as a whole is examining systematically what can be done by government to reduce the disincentives and increase the incentives to mineral investment in the less developed countries --the LDCs. A subgroup of the National Advisory Council chaired by the Treasury Department has been formed to coordinate U. S. Government policy and program efforts relating to mineral and energy development in these countries. Among other matters, this subgroup will examine how public policies could positively influence the private investment decision-making process in the minerals industry.

Jan 1, 1978

By Hemendra N. Kalia

The target to double the coal production by 1995 presents a formidable challenge to the coal mining industry. The mines of future, probably will be located in relatively difficult geological environment because of the exhaustion of the well defined bedded and easily minable deposits. To compound the problems of mining industry will be the reliance of power plants need for coal. The coal must reach the power plants on schedule to avoid expensive blackouts and brown¬outs. It will be imperative that the mines operate without interruptions and at designed capacities. The parameters which have been traditionally responsible for the interrup¬tions of production are: breakdown of production machinery, labor management relations and geological anomalies. Of these three problems, solutions for the first two can be arrived at by developing procedures to correct the situation. A planned maintenance and preventive maintenance program will go a long way in minimizing the equipment breakdowns. Labor relations will eventually improve as the miners begin to enjoy long-term employment. However, with the geological problems, the situation will probably continue to deteriorate and would require careful planning to minimize the impact of geological problems on production and safety. Some of the geological aspects which interfere with production are: faults, washouts, slips and slickensides, water bearing overlying strata, impuri¬ties in the coal seam, and presence of expansive clays in the coal floor. The design of large capacity mines will have to incorporate the geological distur¬bances and mine through them it may become very uneconomical to abandon producing sections because of the presence of the geological anomalies. This paper discus¬ses the geological aspects of coal mining which should receive consideration from the inception of the mining ventures. Pertinent geological aspects are discussed to develop the data base which will aid in evolving safe and efficient mine layouts.

Jan 1, 1976

By G. K. Wilson

This paper will discuss some of the more important aspects to be considered when selecting pumps for mill discharge, cyclone feed or other severe-duty applications Included will be the selection of the pump based on such factors as particle size, particle distribution, head, flow, temperature and pH Other specifics to be covered: The relationship of impeller speed, head and wear factors as they affect pump performance and wear life; the importance of selecting a pump whose performance curve best suits the application; and how the addition of service factors applied to the actual operating conditions can lead to severe operational problems such as premature wear, pump running out on curve, and exceeding horse power limitations.

Jan 1, 1996

By R. S. Kramer

A bulk compositional chemical analysis often provides incomplete information to help the mineral processor when faced with the problem of removing troublesome contaminants in low concentrations. Michigan Tech has developed a unique approach for addressing this problem. A combination of Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and image analysis was successfully used to characterize the species responsible for phosphorus contamination of less than . 05 weight percent in iron ore. An automated routine acquired the chemical signature of each particle on a back scattered electron image. The few particles containing phosphorus were identified from the hundreds of particles examined, and the phosphate phases present were easily characterized.

Jan 1, 1993

By Shijie Wang

The metals of value in tetrahedrite are copper, antimony and silver. A new hydrometallurgical process is proposed to recover these metals from tetrahedrite. The process consists of leaching concentrate with ferric fluoborate, solvent extraction, electrowinning and residue treatment. Products from this process are high-purity SX-EW copper and antimony and a high-grade silver residue that will be further treated in a hydrometallurgical process for early release of silver. The process has advantages, such as achieving rapid leaching rates at modest temperatures with high metal recovery. Most pyrite is not attacked. Thus, it remains in the leach residue along with elemental sulfur.

Jan 1, 2003

By Allan D. Fernie

Growing interest in pit crushing and conveying is evident from the many articles, technical papers, and new equipment development recently presented. Application of a pit crushing and conveying system is complex, as many factors such as mine design, production scheduling as well as initial and ongoing capital and operating costs must be thoroughly and realistically examined. This paper will address the fundamentals to be considered and review several approaches to developing a total system for a new and existing mine situation. The planning function will be outlined and operating and design criteria defined to interface the mining operation and the pit crushing conveying system.

Jan 1, 1983

By R. R. Graham

Echo Bay Minerals operates a 650 tpd gravity float gold circuit at their Manhattan facility. The objective of this paper was to document the gold recovery by size distribution. This was accomplished by studying the material balance of each size fraction as it progressed through each gravity Circuit separator. It proved to be an impossible task. Figure I depicts the gravity circuit. The gravity cyclone underflow goes to two duplex Pan American type jigs. The jig overflow reports to the OK Flash Float Cell. The cyclone hutch product is reground and goes to a full size wilfly table. The rougher table concentrate reports to a pilot size Wi1fly cleaner table. The cleaner and rougher table tails circulate back to the jig feed. The gravity circuit was composite sampled for two to four hours per day for four days. Each sample was taken every 20 minutes. Each composite sample was filtered, dried, repu1ped, and screened through a wet/dry screening procedure. Each size fraction was checked for gold value by fire assay fussion technique. A material balance was run on each size fraction. The tables listing the results are enclosed.

Jan 1, 1989

By Gregg J. Hodges

The Stillwater pt-pd mine and flotation mill are located about 130 km (80 miles) southwest of Billings in Stillwater county, M6ntana~ The pt-pd ore zone stretches about 43 km (27 miles), but varies in thickness from 0 to 6 meters (0 to 20 feet, but generally 3-6 feet) and dips 55-90,degrees from horizontal. The ore is hosted in basic, layered igneous rocks containing about 1% sulfide minerals which include chalcopyrite, pentlandite, pyrrhotite, and minor pyrite. The pt-Pd minerals are intimately associated with these sulfide minerals and are found as precious metal sulfides, tellurides, bismuthnides, and arsenides as well as native Pt metal. Approximately 90 different precious metal minerals have been found, but about 80% of the pd is in solid solution in the pentlandite. The ore assays about 0.1% Cu, 0.1% Ni, 6.2 g Pt/tonne (0.18 Troy ounce Pt/short ton (opt)), 21.3 g Pd/tonne (0.62 opt Pd), 0.21 g Au/tonne (0.006 opt Au), and 0.21 g Rh/tonne (0.006 opt Rh). The ratio of pd to Pt in the Stillwater ore and concentrates is about 3.5.

Jan 1, 1988

By R. W. O. Kersten

The shrinkage method of stoping with pillar support has been used at Agnes Gold Mine since mining commenced. Until recently, rock instability did not have any detrimental effect on safety or production. Presently sill pillars are failing not only on the current production levels, but also in shallower old worked-out areas. The incidence of failure raises the question as to whether the pillar dimensions are adequate at the current working depths and what their size should be at greater depths. The effect of pillar dimensions on the economics of the mining operation is of paramount importance because of the amount of ore that can be left unmined.

Jan 1, 1982

By Diane M. Jordan Tom M. Malloy

As part of the Mine Waste Technology Program (MWTP), a large-scale column test utilizing bacteria and a sulfide ore was conducted at McClelland Laboratories, Inc., in Sparks, Nevada. The MWTP is funded by the U.S. Environmental Protection Agency (EPA) and is jointly administered through an interagency agreement with the U.S. Department of Energy (DOE). The project was intended to illustrate the viability and feasibility of biodegradation technologies to reduce the cyanide to the regulatory level of 0.2 parts per million (ppm) within an acceptable time frame and with low operational costs.

Jan 1, 1999

By James Whitlock, Michael Robert Wilcox

The volume of recently published material in praise of various refractory gold ore treatment methods is impressive. The authors are unfailingly bright, focused and thorough, and as each paper concludes, the reader is tempted to abandon other methods and embrace this truly better way. But there are many "better ways," many different ores, many different environmental requirements and many differ­ent economic circumstances. As we approach each set of cir­cumstances, it would be useful to have an objective way of comparing various methods in order to identify the most promising approaches. This discussion attempts to provide that.

Jan 1, 1991

By Wolfgang Baum

The selection of roasting technology is a complex task which is primarily dependent on the ore mineralogy. Key roasting parameters are directly linked to mineralogical characteristics of the feed and vary considerably between different ore types even in the same deposit. In addition to sulfide refractoriness, other refractory conditions frequently exist. Together with various mineralogical features of the feed, they may complicate roasting testwork and process design. For most roasting scenarios, the critical economic factors are gold recovery, capital cost and environmental performance. This paper will show how these economic factors are influenced by the mineralogical ore characteristics.

Jan 1, 1992

By F. W. DeVries

The preoccupation with cyanide as an environmental issue has been described as virtually an obsession for state and federal agencies enacting regulations for environmental protection. This seems likely to continue in legislative planning, as well. This is despite the fact that the only significant group of cyanide-related incidents has been the bird-mortality occurrences, predominantly in arid areas, and these have been greatly reduced by a concerted effort by operators. What follows is a brief list of areas for which the industry may need either additional information or plans for defensive strategies over the next two to five years.

Jan 1, 1991

By Ian Larkins

The Ruby Hill Mine agglomerates crushed low-grade ore (nominally -1 .5'') with high-grade filtered tailings (filter cake, nominally 80% -65#). Cement is added as a binding agent. The agglomerated ore is then conveyed and stacked on the heap. In 1998 approximately $480 000 was spent on cement for agglomeration. Cement for mill pH control and agglomeration was the largest single reagent cost at Ruby Hill. In an effort to reduce agglomeration costs a test-work program was initiated to investigate alternative binders and optimum binder additions. This paper summarizes the test­work results to-date.

Jan 1, 1999

By Hans von Michaelis

Very little has been published about Cia de Minas Buena­ventura. Don Alberto Benavides Quintana, now in his seventies, founded the company in 1953. This venerable gentleman is a Doyon of the Peruvian mining industry and more has been known about him than about his company. Buenaventura is a highly profitable gold producer with excellent potential to expand gold production in joint ventures with Newmont, Southern Peru Copper (ASARCO), and BRGM as well by developing their own new gold mines. On September 15, The Wall Street Journal published an article titled "Peru's Big Rebound Sets Off Foreign Investors' Enthusiasm."

Jan 1, 1995

By Brian T. Field

Development of cost effective technology for whole ore roasting of refractory gold ores is an important requirement to increase recovery rates as ore grades become more carbonaceous and sulfidic in nature. It is important that the industry focus on the further development of cost effective, environmentally sound technologies to roast this ore. Traditional technologies have centered around bubbling and circulating fluidized beds with and without oxygen enrichment. Fuller Company has developed a process to flash roast refractory ores in its pilot plant with the R&D results, commercial scale up issues, and indicative economics discussed herein.

Jan 1, 1993

By Marshall A. Koval

The future of mining in the United States is in question. The cumulative effects of federal, state and local environmental legislation threaten its survival as the cost of compliance skyrockets. Legislation has created pol ari zat ion between government and industry followed by court action, further increasing costs and delays on permitting and remediations. Regulations often call for excessive and rigid requirements that result in unrealistic compliance goals costing tens of millions of dollars. The costs often exceed the value of the remedy. A growing concern is that proper scientific methodologies and engineering practices are being sacrificed because of political and public pressures.

Jan 1, 1991

By Chris Cox, David Green

Outokumpu has developed the HG or High Grade flotation cell over the past decade. This machine gives upgrading and selectivity performance superior to conventional mechanical cells while maintaining their simplicity, ease of operation and recovery characteristics. The HG design is available in a tank cell configuration which provides a number of benefits in plant design and operation. This paper will describe the HG Tank Cell and the "Virtual Column" concept. Results are given from the operation of the HG Tank Cells at Lac Minerals - Est Malartic in Quebec, Canada. Further discussion of applications for gold recovery is also provided.

Jan 1, 1993

By J. Cooper, M. W. Staub

Environmental management systems (EMSs) have been in use for more than a decade. US mining companies are only just beginning to adopt EMSs. This lag is primarily due to lack of market forces and lack of evidence that EMSs add value over standard compliance programs. Several recent studies concluded EMSs improve environmental performance and reduce costs. State and federal regulatory agencies are using EMSs as an innovative tool to streamline the regulatory process and achieve continual environmental improvements. The climate is right for the mining industry to adopt an EMS model that improves environmental performance and takes advantage of new regulatory programs.

Jan 1, 2004