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By Steven A. Whittle, Robert E. Cook

Years ago, personal computers (PC) were pricey devices destined for who knows where in the process industry. Now their use runs the gamut from low end data acquisition systems to high performance windows into the process area. Their applications range from CAD, CAM, CIM, and CAE to factory floor scheduling, process planning QC, facility management, cell control, and publishing. This discussion traces the evolution of a zinc plant's control automation program beginning with a PC as an operator interface and migrating to higher level work stations. Included in this paper will be a discussion of an Open Industrial System and the role PCs have played in this facility.

Jan 1, 1993

By Jaye Pickarts, Bret Boster, Jack McPartland

Pegasus Minera de Chile, Ltda. is completing three phases of metallurgical evaluation on the Pullalli project to develop a preliminary process flowsheet. A project feasibility study is in progress. The feasibility study includes a proposed process flowsheet designed based on results from the multiple stages of metallurgical evaluation. Phases I and II of metallurgical evaluation included laboratory scale heap leach and milling cyanidation testwork on multiple drill core composites and bulk ore samples from the Pullalli Project. Phase Ill included pilot scale milling/cyanidation testwork on Pullalli drill core composites. The proposed flowsheet includes selective mining and separate processing of low grade and high grade ores. Low grade ore will be crushed and heap leached. High grade ore will be milled leached for 12 hours in an agitated cyanidation circuit. After 12 hours of leaching, sands and slimes will be separated and the sands will be washed using a counter current cyclone (CCC) circuit. Partially leached and washed sands will be added to the crushed low grade ore for heap leaching treatment and permanent placement. Partially leached slimes will be thickened in a high capacity thickener and will be processed in a CIP circuit. Leached slimes will be placed in a tailings impoundment.

Jan 1, 1996

By Luis Elu, Andy Bolland, Jack Simmons

The gold refinery at Barrick Goldstrike Mines has increased production to more than 2,000,000 ounces poured per year while reducing the labor requirement. Safety and health has not been compromised with this increased production and in fact incident rates and exposures have reduced over the past five years. Streamlining procedures, improving ergonomics and the wise use of unique innovations has accomplished this significant achievement.

Jan 1, 1998

By Donald P. Richards, Patrick Ramond, Martin Herrenknecht

Phase 1 of the second line of the Cairo Metro includes approximately 5.83km, of double track tunnels excavated in water bearing sand of the Nile flood plain. Closed face bentonite slurry shield tunnel boring machines 9.43m in diameter were used. State-of-the-art technology was used in TBM operations and guidance, with surface settlements averaging less than 14mm, and alignment deviations averaging less than 25mm. Production rates up to 580m/month were achieved, with average production of 4.8m/shift, 13.4m/day and78m/week. The completed tunnels, lined with precast concrete segments, are completely watertight under 20m of water pressure.

Jan 1, 1997

By P. A. Plunkert, D. E. Morse, L. McCartan, S. F. Sibley

Following the recession of 2001, restrained consumer spending, declines in domestic manufacturing and industrial output, and increased unemployment led to a lack-luster year in the domestic economy. In 2002, the U.S. real gross domestic product (GPD) grew only 2.4%. Significant production declines in the U.S. metals industry were registered by copper, lead and zinc producers. Steel producers, despite a slight improvement in shipments, continued to face strong foreign competition, higher energy costs and lower prices for their products. Homebuilding and other domestic construction sectors— major consumers of nonmetallic mineral products such as cement, brick, glass and stone — remained strong enough to help raise the output of industrial mineral materials slightly above 2001 levels. A strong U.S. dollar relative to other national currencies continued to weaken the competitive stance of U.S. metal and non-metal mineral materials companies alike against foreign producers in markets at home and abroad.

Jan 1, 2003

By Dennis W. Leonard

Let us begin our discussion by looking at historical and current levels of sales of both natural and synthetic zeolites on a world-wide basis. Due to the understandable reluctance of some companies to disclose sales data, some estimation has been necessary regarding the tonnages and values shown in Table 1. We are confident, however, that they are within acceptable limits, especially the numbers referring to natural zeolite.

Jan 1, 1979

By Gordon R. Wicker, Peter V. Avotins, Steven S. Ahlschlager

Laterite ore slurries exhibit Bingham plastic behavior and can be characterized by the magnitude of their yield point and Bingham viscosity. These two parameters are affected by ore composition, solids concentration, and temperature and are used to predict the pressure drop in pipelines and heat transfer coefficients in shell-and-tube heat exchangers. In cycloning of laterite slurries, the calculated cut size is corrected by factors obtained from the rheological parameters.

Jan 1, 1979

By J. B. Platt

Many utility fuel choices 1990-95 defied expectations, with utility decisions and coal market developments ever more closely linked. The Central Appalachian coal boom never occurred; clean-enough coal was developed in the hard-hit Midwest; Colorado-Utah coal surged; Pittsburgh seam production strengthened; utilities embraced Powder River Basin coal; and emission allowance prices collapsed. Competition drove productivity gains, but the future is not a simple repeat. Phase 2 brings fewer viable compliance options. Mega-railroad pricing has become a key risk factor --will this be countermanded by merging utilities and power market competition? Revenue losses from vintage contracts are problematic. Uncertainty also plagues natural gas, in spite of unanimity across major forecasts, since recent experience has been so heavily influenced by the gas bubble.

Jan 1, 1997

By M. Irish

This paper describes the emergency water control measures used at Pegasus Gold's Zortman Landusky mine during the September 1986 flood. The amount of solution stored increased by approximately 78 165 m3 due to receiving 0.2134 m of rain in a 24 hour period. Three methods of water disposal will be discussed including continuous chlorination, batch chlorination, and reverse osmosis. A water management program will also be discussed.

Jan 1, 1988

By Walter E. Heinrichs

To many, petroleum exploration and successful geophysics , are partly synonomous, This is not because natural petroleum is usually concentrated as a liquid, nor certainly not because oil can be detected directly. The reason is Chat geophysics helps to at least better understand and sometimes, to even explain the essential geology involved. That groundwater is similarly a liquid with all but a few of its basic geologic relationships practically identical to petroleum, seems to have escaped many of those most interested and responsible for complete geo-hydrologic knowledge. The paramount need to use every means at our disposal for maintaining and expanding our crustal resources reserves are generally obvious, However, in view of the rapidly mounting requirements, continual re-emphasis is worthwhile.

Jan 1, 1963

By Donald M. Hausen

Microscopic evaluation of trace quantities of metalliferous phases in flotation products requires counting large numbers of particles. Particle counts of many thousands may be required for precision, but not obtained practically by conventional microscopic techniques. A less tedious microscopic method for evaluating trace sulfides in mill tailings was developed for the O'okiep Mining Company in South Africa. Hundreds of thousands of particles were evaluated by this method called "gross-counting." Gross-counting consists of counting microscopic fields rather than point-counting individual particles. Total counts are calculated by multiplying the average number of particles per field by the total number of fields examined over the entire mount. Total gross-counts range from about 20,000 particles for +200 to 100,000 or more for -400 mesh size material in lucite mounts. Sulfides and metallic particles in each field are identified and tallied along with field counts. Totals for each type of metallic particle are divided by the total gross-count to give volume percent which is corrected to weight percent by specific gravity factors.

Jan 1, 1969

By John N. Murphy, Edward F. Fries

The availability of fast, low-cost computer hardware and advanced software is opening new opportunities for minerals extraction and processing. Programmable Logic Controllers (PLC's) are currently used extensively in the minerals industries; this paper looks beyond PLC's and that vintage of “computer control”--it looks toward what the authors see as new in the next five years. Topics covered include expert systems, neural networks, intelligent signal processing, and hierarchical controllers as applied to mining and mineral processing operations.

Jan 1, 1993

By J. K. Mudge, T. Allen, P. B. Johnson

Approximately 6 years ago, Newmont Mining Corporation (Newmont) initiated reclamation/closure at its’ Hollister operation in Nevada. Reclamation/closure challenges existed at three primary areas within the operation. One the open pits had a small, low pH lake. The primary waste rock dump had a collection system for seepage of low pH solution. The heap leach had a typical inventory of process solution. In each of these three areas water quality and water quantity challenges existed. Reclamation/closure techniques were employed that utilized run-on controls, re-sloping, capping/topsoil placement, pit backfilling and vegetation for water quantity control. Water quality controls included installation of passive, anaerobic systems. These mechanisms have effectively limited water volumes that require treatment and effectively treated the water to meet standards.

Jan 1, 2003

By Ian Mcgaffin

P.T. Kellan Equatorial Mining (KEM) is an Indonesian incorporated company owned 90% by CRA Limited of Australia and 10% by PT. Harita Jayaraya of Indonesia. The Kelian gold mine first commenced production in January 1992 and has produced in excess of 21 tonne of gold (675,000 oz) in its first 18 months of operation. The operation is a large tonnage low grade deposit that accepts a low gold recovery by industry standards due to the partially refractory nature of the orebody.

Jan 1, 1993

By James L. Poole

The gold and silver markets from the late 1960's to the present are reviewed and the outlook for these metals in the 1980's is presented. Included in this discussion is a summary of the basic supply and demand balance for gold and silver since the mid-1960's. an explanation of the price formation for the metals, some of the relationships between the prices of these metals and selected economic parameters, and how these factors affect the outlook.

Jan 1, 1981

By T. R. Paquin

Powerful, easy to manipulate, ventilation modeling software is readily available to most mining engineers. Too often when preparing an initial ventilation model, engineers will go overboard in their design, creating a complex model with hundreds of branches. When, in practice, the creation of a less complicated ?to the point? model, containing a few well-constructed branches, would have delivered the same results. In this paper the author will demonstrate, by using actual feasibility report examples, that when designing a ventilation model, engineers should make more use of the K.I.S.S. (?Keep It Simple, Stupid?) Principle. As mining industry consultants we must continue to improve on, and deliver timely and cost-effective results to our customers.

Jan 1, 2009

By Robert C. Meaders

In this paper, autogenous grinding is defined as the combined crushing and grinder of a run-of-mine ore or the product from a primary crusher, in a single stage grinding mill. This is in contrast to pebble milling where pebbles are substituted for steel balls to grind a ball mill size feed. The autogenous mill to compete in efficiency with normal methods of crushing and grinding must not use greater power, must use less labor and steel, and must produce an equivalent product.

Jan 1, 1963

By Anthony Busigin, Charlett Busigin, Colin R. Phillips

For the purposes of measurement and dosimetry of airborne radon daughters in uranium mines and elsewhere, it is important to understand their physicochemical state. This work deals with the chemical fate of 218Po in air. Extensive experiments were performed to determine the rate of neutralization, diffusion coefficient and fraction born charged of 218Po in air. The experiments were performed in a specially constructed apparatus of well-defined geometry. Careful control of experimental conditions made it possible to obtain more precise and detailed quantitative data than previously possible.

Jan 1, 1981

By Craig Ammar

JAMIE DAVIS: Our next speaker is Craig Ammar. He's director of equipment management for Cyprus Climax Metals Company. He has, prior to this assignment, been responsible for maintenance at Bagdad Copper, Cyprus' Miami smelter, and Thompson Creek. Like Jerry, he's very shy and retiring, and doesn't have any strong opinions about maintenance. INTRODUCTION CRAIG AMMAR: The ultimate goal behind implementing a proactive equipment management process is to provide capacity assurance and ultimately increase an organization's ability to generate revenue while reducing operating costs. Targeting such lofty objectives has brought many an organization to its knees, utilizing new maintenance techniques, concepts, and technology aimed at making our lives better and more organized. The root cause of such frustration generally stems from a lack of understanding or support for the fundamentals of implementing a proactive equipment management process. There are just two types of maintenance programs, reactive and proactive. It's an established fact that you need a little of both to run an effective equipment management process, obviously more of one (proactive) than the other. Here are some telltale signs that your equipment management process is in trouble: -Maintenance is performed as a knee jerk reaction when equipment fails. -Repeated and frequent equipment failures occur, with no focus on eliminating the root cause. -Sketchy, inconsistent, unclear preventive maintenance is performed or there is no support for the preventive maintenance process. -No predictive maintenance technology process is in place, or little support for predictive maintenance exists. -Less than 50 percent of your work is generated by the maintenance group resulting from inspections.

Jan 1, 1998

By Robert M. St. Louis, Janet M. Edgecombe

The Mercur Mine's autoclave is an alkaline pressure oxidation system, operating at 220°(428°F) and 3061 kPa (444 psig) (total). Up to 725 metric tons (800 st) of ore, grading 2.02 g per mt (0.059 oz/st) Au and containing 1 to 2% sulfide sulfur, are treated daily in this circuit. A mineralogical and chemical investigation was initiated to locate the cause of lower than anticipated gold recoveries. Greater than 70 wt. % of reduced sulfur is oxidized; therefore, the autoclave is operating at specification. The low recoveries were attributed to increased concentrations of organic carbon in refractory ore. Activated carbon concentration in the attached CIL circuit was increased from 15 to 40 g per 1, leach temperature held below 21°C (70°F), and carbon flow changed to counterflow. These measures resulted in gold recovery improving from 75 to 82%.

Jan 1, 1990