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By Corale L. Brierley

This paper lists commercial bioheap and stirred tank bioleach operations and explains the status of these operations. A total of 17 commercial-scale bioleaching plants have been commissioned. Bioleaching plants are divided into two technology applications: bioheaps and aerated stirred­tanks. In bioheap leaching, secondary copper ores or sulfidic refractory precious metal ores are crushed and bioleached on pads. Stirred-tank technology is used to bioleach base and precious metal concentrates.

Jan 1, 1999

By Brian D. Smith, Batric Pesic

Typical sulfide gold bearing ores are refractory to standard cyanidation practice. This type of ore always needs some form of oxidative pretreatment to destroy the original host mineral matrix to make the cyanidation possible. The oxidative pretreatment can be achieved by roasting, autoclave leaching, bioleaching, or some other chemical method. Today, the most common practice of ore oxidation is either roasting or pressure leaching. The other methods are still considered developmental.

Jan 1, 1992

By Kenneth B. DeGraaf

The development of precious metal recovery processes using chloride systems has mostly evolved from the development of chloride based treatments for base metal concentrates or ores. The recovery of silver from chloride solutions within a process designed for the treatment of base metals usually is part of a solution purification stage. This paper discusses the development of the silver recovery stage used in the GCM HydroCopper process.

Jan 1, 1990

By W. H. Jay, F. Lawson, D. F. A. Koch

Ion exchange resins may in the future displace activated carbon in gold plants where cyanidation is practiced. Recently patented technology based on interpenetrated polyurethane polymers shows that these new materials offer significantly improved loading kinetics over both activated carbon and commercially available ion exchange resins. These polymers are not restricted either in particle size or in density and therefore offer the gold industry the potential for a further technological advancement.

Jan 1, 1995

By C. C. Nolan

As the size of the mills get larger and the liners get heavier, abetter means had to be found to handle liner replacement. McLellan Industries is famous for their innovative ideas andwas called upon by an engineering company to develop a mill liner crane. The first crane was developed for Similkameen about 1969 to serve a 32' Ø X 14' Long SAG Mill. The next was Island Copper in Port Hardy, B.C., the same size as Similkameen in 1970. At that time, we took existing hydraulic cranes and modified them to meet the mill configuration. In 1973, we developed a completely new approach for the Southern Peru copper mine at Tacna, Peru for a Ball Mill, size 16'-6" Ø X 19' Long. Each installation required a design study to meet the change in mill size, trunnion size, elevation of floor to feed trunnion, area at the feed or discharge end of the mill. We have supplied self-propelled units as well as lift in. When there is no room at the feed end and if the mill has a trunnion overflow discharge, we have the mill supplier provide a structural frame to span the sump and move the mill liner handier into position with the use of the overhead crane or a mobile crane.

Jan 1, 1999

By P. Richardson, B. Sceresini

The carbon-in-pulp and the carbon-in leach process for the recovery of gold and silver from cyanide leaching of ores is now widespread in the precious metals mining industry. However the presence of various base metals can have a detrimental effect on the efficiency and the economics of the process due to high cyani,:••? consumption and a reduction in leaching and adsorption rates resulting in poor recovery of the precious metals. Furthermore the presence of fast leaching and adsorbing metals such as copper can significantly reduce carbon loading capacity for the precious metais thereby necessitating a higher carbon inventory, more frequent stripping and poor bullion quality resulting in higher production costs. This paper describes the development and application of a process for the recovery of copper and and the recovery and re-use of the associated cyanide from the leach circuit at the Mt. Gibson Gold Project in the Murchison Goldfield in Western Australia. The process provides a means to counter-act the detrimental effects of the copper which occurs in the ore as various oxide and sulphide minerals including an extremely fine chalcopyrite powder. It has the added benefit of recovering the base metals in this instance copper, in a saleable form. The process is subject to a patent application by Reynolds Australia Metals, Forsayth N.L. and the author.

Jan 1, 1991

By Chris Crowl

Employee involvement does not directly correlate to performance improvement. A key ingredient is the introduction of new Human Resource Systems that promote both performance improvement and employee involvement. Many organizations have tried to use employee involvement as the ''fixer" of performance issues-and seen their performance deteriorate further. They failed to realize that the entire human resource strategy must be connected to the goals of performance improvement and that greater employee involvement is only one tool in that strategy. So what are Human Resource Systems? These are systems that all managers use to get work done. Most of us are familiar with basics such as planning, assigning work, checking progress (auditing), completing assignments. We also commonly think in terms of staffing, training, compensation, or corrective action. All of these are human resource systems. All must be designed to support what you are trying to accomplish with your people. We call that the Human Resource Strategy. Let's examine one part of a total strategy intended to support more employee involvement at Kennecott Utah Copper-the hourly job structure. The design of hourly jobs directly affects how many employees of different capabilities are required to get the work done. It begins to answer some fundamental questions: • What are the roles and accountabilities of each employee? Do they have enough information to make decisions, to take responsibility for their work?

Jan 1, 2004

By Richard R. Klimpel

In a process-oriented production environment, the first objective of any plant engineering effort is to safely produce sufficient product output with an existing plant layout to provide a profitable return to the plant owners and stable employment for plant employees. In such an environment, the terminology macro-engineering means looking at a plant from a perspective beyond "putting out routine fires" or "keeping the plant running." It means asking questions like: • What are the current equipment bottlenecks in the existing plant? • What portion of the plant is most sensitive to fluctuations in raw feed characteristics or other processing condition changes? • If one had X dollars to spend beyond routine maintenance, how could it be best spent to have the greatest impact on overall plant profitability? • What portions of the plant do we know least about? While these questions may seem obvious, they often go unasked due to time pressures, limitations on people or other resources and poor profitability of the existing plant. Even when the questions are asked, frequently a high level of personal bias or a lack of accurate information lead to less than optimal answers and sometimes a lack of confidence in engineering technology. Therefore, in a majority of process plants, there has been little serious change in the equipment layout or engineering operation practice since the start-up of the original plant design.

Jan 1, 1992

By Levent Ozdemir, Gerald Dollinger

An extensive series of linear and rotary cutting tests were run in soft and medium strength rocks at the Earth Mechanics Institute of the Colorado School of Mines to investigate the possibility of very high speed mechanical excavation for tunnel, raise, and shaft boring. The results of these tests demonstrate that cutter penetrations of 38.1 mm (1.5 inch) and cut spacings up to 228.6 mm (9 inch) are possible in such rock without exceeding the bearing capabilities of the cutters. It was also demonstrated in vertical boring tests that continuous excavation rates up to 38.1 m/hr (125 ft/hr) can be achieved with state-of-the-art technology provided sufficient thrust and torque is available. A predictor model for soft rocks was also developed using the test data. Analysis of this model shows that the errors between the predicted and observed cutter normal loads appear to be independent of cutter diameter, tip width, cut spacing, and depth of penetration. This suggests that the structure of the model is correct with respect to these variables. An analysis of the coefficients in the model was also made and a correlation found between the principal coefficient and Unconfined Compressive Strength. The second coefficient in the model was found to be similar in magnitude to rock properties such as Brazilian Tensile Strength, Shear Strength and Point Load Index.

Jan 1, 1989

By Mustafa Kumral

The study area is located in the Alpine-Himalayan zone in Turkey. Geologically, this is a very complicated region, and the rock units generally are divided into two groups as either allochthonous and autochthonous. Tectono-stratigraphically, the units are Paleozoic quartzite, black limestone, arkosic sandstone, interlaminated radiolarite and Triassic limestone, thick Jurassic limestone, detritic limestone with alternating Eocene Nummulites beds and cream-green marl, Miocene siltstone, and ophiolite. Trachyte, trachyandesite, feldspathoidal trachyandesite porphyry, tuff, and pumice formed by volcanism during the Plio-Quaternary also are present. Recent alluvium and slope detritus locally cover all the other rock units. A number of sulfur outcrops occur in the area. Among them are outcrops at Keciborlu, Yelliyatak Hill, Buyuk, and Kucuk Kukurt Dere. The most important sulfur deposits are found in volcanic tuff and siltstone-marl, and they include highly organic material. Sulfur may accumulate around recent gas diffusions and also as massive formations. The information about local geology and sulfur isotopes shows that the sulfur originated From the crust and probably comes from organic-rich Paleozoic and Triassic units. The sulfur did not move between Triassic and Pliocene time. However. Plio-Quaternary volcanism did cause movement of the sulfur, and this was followed by formation of the secondary sulfur due to post-tectonic thermal activities and the mixing of other surface waters.

Jan 1, 1999

By John A. DesLauriers, Hans J. Broennimann

INTRODUCTION The early record of tunnel excavating machines in hard rock tunneling has not been one to particularly brag about. We have all heard the stories of major difficulties when trying to break hard rock with machines at promised advance rates of several times that of conventional drill and blast. Unfortunately, sometimes this has not happened. It has been through this trial of the past generations disappointments that today's TBM's have evolved to their present high level of performance in a wide range of ground conditions. Today's machines offer much increased reliability and durability. This translates into high availability to the tunnel contractor. Although there still are occasional disappointments being reported, the state of the art is that reliable and predictable machine excavation of rock now is both a reality and well founded expectation. The most recent editions of Atlas Copco's MINI/MIDI Fullfacer, we feel, make a strong contribution to the reliable performance of todays TBM's---especially in small-size rock tunnels. This report will, 1.) explain the equipment and effect of rock both on the cutting technique and machine performance; 2.) list advantages of the non-circular shape, during and after construction; 3.) list applications in civil and mining industries; 4.) discuss North American experiences, performance and costs; 5.) list advantages over drill and blast and; 6.) discuss briefly lease arrangements.

Jan 1, 1979

By Tom Skodack

Mine and tunnel contractors face a complex environment-one in which economic risks are high, operating costs grow ever higher, ore grades are lower or recovery more difficult, and civil construction projects are intensely competitive on a world-wide scale. Within the context of this environment, the risks and rewards of proper machine selection for rock excavation have become proportionately large. Speed, depth and scope of analysis, and extensive supporting information are indispensable in the selection process. Equipment designs and their applications are also myriad and diverse. Several equipment alternatives and excavation techniques may have to be evaluated at once to choose the most cost-efficient approach. The following examples are typical of the current demand for more detailed equipment analysis: • An aggregate supplier starts a new quarry. He knows his targeted tonnage, blasting restrictions, and previous operating costs from other quarries. But he must improve on his old costs. What drill pattern, hole size, and bench height will give lowest cost per ton? How many crawler drills and what type will produce this tonnage most efficiently? • A mine is using a fleet of twin pneumatic ring drills for long hole drilling to initiate their cave. The mine is facing both air shortages and increasing operating costs with decreased efficiency in the ring drill fleet. If they invest in new hydraulic long hole drills, what impact will each drill unit have on production? Each twin drill unit? What configuration gives best operator efficiency and subsequent reduction in manpower? Which configuration gives the best return on investment? • A tunnel contractor is bidding a long straight water tunnel by conventional drill and blast methods. What is the optimum number of drill booms for the tunnel cross section and excavation schedule? How many rounds per day can he achieve? What are his total project drill, blast, and muck costs? In the past, such questions could be answered, but only approximately at best. One good prediction could involve many hours of laborious calculations that had to be repeated each time a new parameter was introduced or an existing parameter changed. In 1980, increasingly complex analysis, coupled with increasing need and quick response times demanded by industry, led Atlas Copco's project department to turn to the computer. New computer programs based on theoretical considerations and three decades of worksite performance data were developed for evaluating mine and tunnel contractors' equipment needs, productivity, and partial or total operating cost calculations for most conventional drill and blast excavation techniques-including shot rock loading and transportation. This Computerized Analysis of Rock Excavation-or CARE-program has since been available to the mining and construction industry. From each program specific results can be pre- dicted, including: • Productivity Calculations-Rock drill penetration rate for a given drill, hole size, and rock type, optimized for the best drill steel life; net machine productivity (drill-out time or drill meters-footage-per shift); total drill round time, including charging, blasting, loading, and haulage; suggested drill pattern, computer printed, including hole size for a given rock drill, rock type, and associated blasting restrictions for either drift rounds or benching applications; long-hole drill meters (ft) per drill shift; breasting down (upper drilling) drill meters (ft) per drill shift; and comparison between continuous loading machine capacity and LHD capacity. • Operating Cost Calculations-Operating costs expressed as cost per drill meter (ft), cost per cubic meter (cubic yard) of excavated rock, and cost per meter (ft) of tunnel advance. These costs may be calculated using as many cost centers as the mine, quarry, or tunneling contractor wishes. Specific operating costs may cover drill rig operating costs only, less capitalization; drill rig operating costs, including amortized equipment investment; drilling and blasting costs; drill, blast, load, and haulage operating costs; long-hole drilling operating costs per drill meter (ft) or per blasted cubic meter (cubic yard) of rock; and loading and transport operating costs. In all the above cases, any number of cost and capacity calculations may be run by simply changing important cost center variables to judge their net effect. Accuracy as a Function of Input Data and the Statistical Data Base Accuracy of a projection clearly depends heavily on the data base from which the projection is drawn.

Jan 11, 1982

By Jon P. Thorson, James W. Babcock

The second Belt Symposium in Missoula, MT, Oct. 9-16, 1983, was designed by its conveners as a field conference on progress in the Proterozoic Belt Supergroup rocks. The symposium was sponsored by the University of Montana with corporate support by Anaconda Minerals. Asarco Inc., Exxon Minerals Co.. Hecla Mining Co., Molycorp Inc., Noranda Exploration Co., and Utah International Inc. Introduction The Belt Supergroup is a thick middle Proterozoic sedimentary sequence deposited in a basin along the edge of the North American craton. Subsequent geological events have modified the basin so its remaining rocks outcrop in Montana, Idaho, northeast Washington, southeast British Columbia, and southwest Alberta. The Canadian equivalent of the Belt is called the Purcell Supergroup. Several similar age basins occurred along the western edge of the Proterozoic North American craton. The sedimentary sequence in the Belt basin aggregates is more than 18 km (60,000 ft) in the thickest section, where the bottom is still unexposed and the top removed by erosion. The limits of the Belt basin are poorly known because of later sedimentation and tectonic disruption. Knowledge about the Belt terrane has been difficult and tedious to obtain because the rocks are generally monotonous and fine-grained. During the last decade, new 1:250,000 scale reconnaissance maps of most of the Proterozoic Belt terrane were published, open-filed or otherwise brought close to completion. These maps provided the opportunity and challenge to consider the stratigraphy and tectonics of the Belt Supergroup as a complete basin. This broader view has contributed greatly to the solution of numerous geological problems created by previous, more focused work. Along with the availability of better geological base, there have been new exploration developments. The 1973-1983 decade saw proof of the commercial viability of the Cu-Ag mineralization at the Troy mine. The conclusion was also accepted that the Sullivan mine was a sedimentary massive sulfide. So was the conclusion that the Cu-Co mineralization at the Blackbird mine at Cobalt, ID, was the result of similar submarine exhalative processes. And there were discoveries of another Cu-Ag deposit "larger and higher grade" than the Troy mine and of two new massive sulfide districts. The Belt-Purcell terrane has long intrigued exploration and mining geologists as the host of Pb-Zn-Ag veins of Idaho's Coeur d'Alene district and of the Sullivan mine at Kimberley, British Columbia, one of the largest Pb-Zn-Ag deposits in North America. In the mid-1960s, Bear Creek Mining Co.'s discoveries of the stratabound copper-silver occurrences in the Revett Formation brought new interest in the basin's geology. The recognition of the Sullivan ore body as a sediment-hosted massive sulfide has also generated minerals exploration activity in the US portion of the Belt basin. This activity increased again after the Australian discovery of the world class Olympic Dam deposit at Roxby Downs, South Australia. This occurred because of some suggested similarities in the regional geologic setting of the Belt basin with the Adelaide geosyncline, the host for the Olympic Dam deposit. Technical Sessions Technical sessions topics included Lower Belt and Ravalli Group stratigraphy, Middle Belt carbonate and Missoula Group stratigraphy, Belt-Purcell stratigraphy, structure and tectonics, strata-related mineral resources, geochronology and geophysics, geochemistry and isotope geology, and a summary of significant problems. Evening poster sessions dealt with the topics and papers presented each day. Since the first Belt Symposium, mapping of the stratigraphic units and their tectonic setting has enabled geologists to progress in conducting a basin analysis. Belt Symposium II revealed no concensus on many aspects of belt geology. However, basic stratigraphic studies have reached the point that models can be constructed. The Prichard Formation is equivalent to the Aldridge Formation, but detailed correlations were not previously available. Studies were made by Finch and Baldwin (Cominco American) and by Cressman (US Geological Survey). These studies established important correlations of key markers within the Aldridge Formation to units in the Prichard Formation. This will help eliminate geologic interpretation problems at the US-Canada frontier and make Belt basin reconstruction more accurate. Also, the Sullivan ore deposit was shown to be formed in the deeper distal part of the basin. This contrasts to the more proximal depositional position of the Prichard Formation. Hamilton

Jan 6, 1984

By T. L. Heidrick

Late Cretaceous-early Tertiary Cordilleran porphyry Cu-Mo districts and their consanguineous Zn-Pb-Ag-Au-W vein and replacement deposits of the Rocky Mountain region comprise one of the largest, best studied, diverse, complex, puzzling, and richest compound metallogenic provinces on earth. A concise space-time definition of intermineral plate, regional and local structure-tectonic frameworks is crucial to deciphering their diachronous metallogeny and enhancing the explorationist's odds of future discovery.

Jan 1, 2013

By W. T. Plummer

• The SuperBowl is a fluidized bed, semi-continuous, enhanced gravity separator for gravity gold recovery. The market for this type of equipment has, until recently, been dominated by a single supplier. Many mineral processors have encouraged the SuperBowl designers to develop competitive equipment for obvious reasons. • The primary beneficiary of competition in this field will be the mineral processing community because legitimate competition fosters continuous improvement in product and price.

Jan 1, 1996

By T. Maniatis, T. Pickett, B. Wahlquist

Biological destruction of cyanide in mining waters has been demonstrated effective in the lab and in the field. Applied Biosciences Corp.’s ABMet water treatment technology is used in the mining and other industries for the removal of various inorganic contaminants including metals and nitrate. An aerobic ABMet-CN process has shown great promise in efficiently and effectively removing cyanide from even very cold waters. Bench and pilot data will be presented.

Jan 1, 2004

When multiple mines operate in an area there are social, economic and environmental impacts which cumulate over space and time. These impacts require special attention. A collective approach is required to identify, assess and manage them. No assessment of sustainability of mining can be considered complete without accounting for cumulative impacts. This paper proposes a framework and typology to deal with cumulative impacts and tests this in a coal mining area in NSW Australia.

Jan 1, 2007

By D. Hulse

"The science of “optimal economic pit design” has been highly refined in the last decades. Even with the proliferation of optimizing and heuristic algorithms exploiting ever faster computers, the most common input is a single block model and a single set of cost assumptions, each of which is an estimate and prone to errors. An analysis of price assumptions produces a suite of nested economic shells, each with its own quantities of ore, waste, grade, and profit, but due to irregularities in the mineralized body, the growth of these shells can be erratic. To control the impact of the errors of the model and cost assumptions when choosing the pit shell for design, graphs of pit shells characteristics, such as stripping ratio, cost per unit of product and profit/ton, can be analyzed to consider points with higher stability, or robust pits. Selection of robust shells for a pit limit and for push backs can help to understand the impact to profit and risk. The robust shells also guide the preferred solution sets for final pit and cutoff optimization. INTRODUCTION “An open pit mining operation can be viewed as a process by which the open surface of a mine is continuously deformed. The planning of a mining program involves the design of the final shape of this open surface.” Optimum Design of Open-Pit Mines, Lerchs, H. and Grossmann, I. Transactions C.I.M. Volume LXVIII 1965. Traditionally an analysis of economic pit shells and sensitivity was performed by varying the input metal price. This was done with both floating cone algorithms as well as early versions of the Lerchs-Grossmann (L-G) algorithm. This gave an indication of the pit sensitivity to price but since other variables also change, some with metal price (perhaps steel and equipment), and some independently (fuel and tires) the understanding of these different pits was restricted. In addition, a run of the program could take hours, making a detailed analysis of small changes unwieldy. The L-G algorithm was programmed by a variety of people and sold as part of commercial mining packages, however it was first and most successfully commercialized by Jeff Whittle in 1984. When Whittle’s 3-D™ was expanded to 4-D the parameterization of the economic inputs was considered and the ability to run a suite of “pit shells” became automatic. The competing NPV Scheduler™ program sold by DataMine™ offers similar pit shell analysis capabilities."

Jan 1, 2018

By Juan L. Yarmuch, Gonzalo Sepulveda

Medium- and short-term mine planning holds immense significance in optimizing production and resource utilization. It serves as a vital link between the long-term strategic plans and the day-to-day operational activities of a mine. In this context, a mathematical formulation is proposed to incorporate mining width constraints into the production scheduling process, aiming to maximize the net present value (NPV) of the schedule while ensuring enough room for the operation of mining equipment.

Jul 1, 2024

By M. J. Virnig, J. M. W. Mackenzie, M. W. Johns

The properties of Henkel's Aurix® resin which uses a guanidine functionality to recover gold by ion exchange have been described in publications of the International Mineral Processing Congress and Randol International (1)(2). The purpose of this paper is to provide an update on the results of further testwork using Aurix®. Specifically, this paper presents the first results of resin in pulp testing, all the results previously reported were for testwork carried out using synthetic gold leach solutions.

Jan 1, 1995