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"INTRODUCTIONThe Kidd Creek Concentrator is located 28 kilometers east of the city of Timmins, Ontario. Two types of ore are treated; 'A' type, a copper-zinc-low silver ore producing copper and zinc concentrates, and 'C' type, a copper-lead-zinc-high silver ore producing copper, lead and zinc concentrates.The ore is processed at a combined rate of 12,400 metric tonnes per day through four parallel grinding and flotation divisions. Three divisions treat the 'A' type ore and the fourth treats the 'C' ore. Each division is fed from its own fine ore bin.This paper reviews the grinding section with specific emphasis on grinding media consumption and the factors affecting it as related to 'A' type ore. At Kidd Creek there was an awareness that grinding media consumption varied on a weekly and monthly basis. The reasons for this variation was usually attributed to ore hardness as evidenced by short term variations in the circuit feedrate and head assays. However, there has been a diversity of opinion published in recent years regarding the factors contributing to steel consumption. This initiated a study of historical Kidd Creek operating data, from the period 1970 to 1986 inclusive, to determine the effect of various operating parameters on media consumption. The results of the study could then be used as a baseline for future media consumption testwork."

Jan 1, 1988

By Karla Kaboth, Brad Garraway

"The surface of many concentrate thickeners has traditionally looked like that of a flotation cell. Over the last three years Normandy Golden Grove Concentrator, in partnership with Outokumpu Technology have developed and implemented an innovative breakthrough deaeration technology to address this problem.When installed in the thickener feedline, the system successfully detached air bubbles adhering to the solid particles and removed air bubbles from the feed stream, subsequently presenting a fully deaerated feed to the thickener feedwell.Tests to date have shown an 80% reduction in overflow solids. As a result, costs associated with concentrate loss and measures to recover concentrate that settles in process tanks and ponds have been minimized.MOTIVATIONIt is recognised in mineral processing operations that the entrainment of finely divided air in thickener feeds can cause significant problems in the operation of a thickener. This is particularly the case with thickening of flotation concentrates, in which air bubbles are strongly attached to the mineral particles and are difficult to remove. Such particles attached to fine air bubbles rise to the thickener surface, and hence over the weir and into the thickener overflow. High solids carryover can lead to a direct loss of mineral product, and if the product settles in process water tanks and ponds, the recovery of this product by means of intermittent dredging operations is usually expensive and inconvenient.Many concentrate thickeners are fitted with devices which attempt to alleviate this problem. Froth rings or baffles, skimmers and froth sprays, all play a part in reducing the amount of solids carried over into the overflow. However, many froths are very stable and persist despite these measures. In the worst cases, a thick froth layer forms which builds up to a depth greater than the froth ring, and hence may overflow or pass beneath the ring . Any concentrate that finds its way past the froth ring can also cause blockage of the overflow weir and launder, and has the potential to upset clarification performance by cutting off sections of the overflow handling system. The formation of a froth layer on the thickener also makes it more difficult for the operator to monitor the clarification performance."

Jan 1, 2001

By M. J. Fairweather, Keith Lee, Naseem Mian

"The initial metallurgical response of the lead flotation circuit at Cominco Alaska's Red Dog Mine was substantially below feasibility expectations. A program of diagnostic mineralogical analysis pointed the way to a number of process improvements, including simplification of the flow sheet and installation of a large flotation column as a lead cleaner. A diagnostic mineralogical analysis of the improved circuit shows that inadvertent activation of both sphalerite and pyrite has been substantially reduced, resulting in significant improvements in metallurgical performance. Directions for further improvements to the circuit performance are suggested by the recent analysis.IntroductionRed Dog is a high-grade, sedimentary exhalative (sedex) deposit with relatively simple mineralogy. The primary non-sulphide gangue minerals are quartz and barite, with minor barium carbonate (witherite). The iron sulphate minerals, siderotil, rosenite and copiapite occur variably throughout the deposit. Mineral texture is variable ranging from liberated sphalerite grains visible to the naked eye to intergrowths, particularly between sphalerite and galena, to less than ten microns. Both pyrite and marcasite are present. To date no enhanced reactivity of marcasite has been observed. For this discussion, ""pyrite"" will be used to refer to both iron sulphide minerals. In common with other sedex deposits, Red Dog contains organic and sulphur impurities."

Jan 1, 1997

By B. Hart, J. Marois

"Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM–EDX), and Time of flight secondary ion mass spectroscopy (TOF-SIMS)were used to analyze pyrochlore grains from Niobec froth flotation plant. Samples from the mill feed, pyrochlore rougher feed, pyrochlore rougher concentrate, and tail were analyzed in order to identify a potential relationship between pyrochlore matrix composition and selective separation. SEM-EDX analyses indicate that pyrochlore grains with high Fe content appear to be less recoverable than those with a lower Fe content and that the flotation response is related to matrix Fe rather than Fe occurring as inclusions. TOF-SIMS was used to analyse the surface of high Fe and low Fe pyrochlore, in order to identify a potential relationship between pyrochlore matrix composition and the related effect on cationic collector adsorption (tallow diamine). Surface analyses of pyrochlore from a conditioning test show that species indicative of the collector favour the surface of Fe poor pyrochlore relative to the Fe rich variety. The results from the conditioning test illustrate a negative relationship between collector loading and the presence of Fe and related oxidation species. This study identifies the link between pyrochlore matrix Fe content and, the presence of surface oxidation products, to collector loading. Poor Fe rich pyrochlore recovery noted in the Niobec froth flotation plant may be partially explained by this mechanism.INTRODUCTIONPyrochlore, the most abundant niobium containing mineral (Perrault and Manker, 1981) is economically recovered in Brazil, China, and Canada (Niobec) (Kouptsidis et al., 2008). Since 1974 Niobec has been extracting niobium from the St-Honorécarbonatite deposit. Niobec is the only operating Nb extraction facility in North American and one of the three major world producers of ferroniobium (Dufresne and Goyette, 2004; Belzile, 2009).Flotation is the preferred and most cost-effective method for pyrochlore recovery (Burks, 1958; Shapolov and Polkin, 1958; Zakharov et al., 1967; Razvozzhaev and Nikiforov, 1972; Bogdanov et al., 1973; Abeidu, 1974; Raby and Desrochers, 1975; Wilson, 1979; Biss and Nadeau, 1982; Biss, 1985). With the aim of optimising the flotation process for the Niobec ore, numerous experiments were performed on the influence of surfactants and type of water to optimise pyrochlore recovery and grade during flotation (Gomez et al., 1987; Rao et al., 1988; Dufresne and Goyette, 2004; Belzile, 2009)."

Jan 1, 2013

By R. Nendick

"IntroductionThe Ancient Egyptians recovered gold from the mud in the bottom of ponds by having teams of maidens sit around the pond dipping goose feathers dipped in grease into the mud. The gold would preferentially stick to the oily surface and was periodically washed off to give a gold concentrate. This was a forerunner of today's flotation processes.In Greek mythology Jason and the Argonauts pursued the Golden Fleece, which was a primitive form of gravity concentrate produced when gold ore slurry was passed over a sheeps fleece. The heavy gold settled and was caught in the fleece, producing a rich concentrate that allowed Jason & Company to perform the first recorded case of highgrading. The process was a forerunner of todays shuiceboxes used in placer mining.From these simple beginnings, gold metallurgy has progressed to a state where very complex flowsheets are proposed, sometimes to perform a simple metallurgical task. Figure (i) shows a hypothetical flowsheet to identify the range of unit processes that might be brought to bear on a refractory ore. The flowsheet identifies the three primary areas of gold metallurgical operations:Ore PreparationExtractionRecovery."

Jan 1, 1986

Project Schedule ?Construction 2005 ?2008 (3 years) ?Operations mid 2008 ?2020 (12 years) ?Closure 2020 ?2023 (3 years) ?Post-closure monitoring Victor Economic Facts ?$982 million investment; ?$110 million already invested in the Project; ?1100 person years of employment in construction; ?375 full time positions during operations;

May 1, 2006

By Graham A. Karklin

"The Echo Bay Mines silver property is located 875 air miles north of Edmonton, Alberta. The mine is on the east shore of Great Bear Lake at Port Radium which is twenty six miles south of the artic circle, in the North West Territories.HISTORYThe area was first surveyed by J. Mackintosh Bell of the Geological Survey of Canada in the early nineteen hundreds. In May 1930, Gilbert LaBine staked claims at Port Radium called ""Cobalt"" and ""Cobalt I"". What he had discovered was an extremely rich vein of pitch-blend. These claims were the birth of mining in this area. The first ore shipment of pitch-blend was hand-picked and flown out of Port Radium in 1931. LaBine's discovery of pitch-blend became of world-wide importance with the outbreak of World War II. In 1939 the splitting of the uranium atom brought this area into world focus. It is generally believed that it was ore from this area that was used in the production of the devastating bombs which were dropped on Japan.It was at Port Radium that the leaching process for uranium extraction was pioneered. The resultant methods have been modified and adopted for use around the world. The mine was originally owned by Eldorado Gold Mines Limited. Echo Bay Mines leased the property in 1964, subsequently purchased it, and have been producing silver and copper every since."

Jan 1, 1981

Conventional waste management practices produce two waste streams for the construction of separate disposal facilities. The design of tailings impoundments is usually controlled by physical stability. Waste rock materials offer high shear strength characteristics for waste dump construction, however the hydraulic properties promote oxidation. The problem of oxidation is significantly reduced for tailings due to a fine texture that augments water saturation. Co-mixing of tailings and waste rock involves the intimate blending of tailings and waste rock to create a new material with superior physical and hydraulic properties. The new material has a low hydraulic conductivity, low compressibility, high water retention capacity and high shear strength. Co-mixed tailings and waste rock restrict oxygen entry and water seepage to minimize acid generation and metal leaching. Co-mixed tailings and waste rock may be used to construct cover systems, internal barriers and seals, confinement structures and full depth waste repository. The results of a laboratory program to characterize the physical and hydraulic properties of Comix tailings and waste rock are presented here. Various ratios of tailings were blended with three distinct waste rock materials. The saturated hydraulic conductivity for the Co-mixed materials was found to vary between 2 x 10-7 m/s and 5 x 10-8 m/s depending on blend ratio, waste rock type and compaction. This paper introduces concepts for the co-disposal of tailings with waste rock and evaluates the hydraulic behaviour of a Co-Mix waste system. The potential benefits of Co-Mix are shown for a typical mine.

Nov 1, 2002

By P. A. Selvadurai

This paper presents the results of a research investigation leading to the development of a technique for the measurement of the surface permeability of Indiana Limestone. The tests are conducted on a cuboidal block of the limestone with a flat surface that can be sealed to create a circular aperture through which water influx can take place. Computational results for Darcy flow are used to interpret the results of the experiments. The water entry area can be moved over the surface area of the block to investigate, quite conveniently, the distribution of permeability across the surface of the limestone block sample.

May 1, 2009

By A. F. Banks

"The last time I spoke to you the potash industry was at a low point. Markets were bad and the industry depressed. Many people had left and there was very little being done in terms of development. The current situation is very much changed. The oversupply conditions have given way to a very tight supply capability. All of the firms in the business are expanding in one way or another. These expansions will run from simple debottlenecking through to complete new projects.In New Brunswick, the Potash Corporation of America is proceeding with a new project and the Dennison - Potacan Project is in progress. In Saskatchewan, the Potash Corporation of Saskatchewan has an ambitious 2.5 billion dollar expansion program underway while those in the private sector are taking a somewhat less ambitious but equally significant approach to obtain further tonnage out of existing facilities.The significance of these expansions to mineral processors is that we can expect to see expanded employment opportunities and through necessity a surge in innovation and development in an industry that has been traditionally very conservative. This presentation will review potash processing with a view towards highlighting some of the more recent developments."

Jan 1, 1982

By M. Massinaei, M. R. Yarahmadi, S. Zeidabadi, M. Oliazadeh

"Although the majority of new flotation column installations continue to be for cleaning or recleaning, an increasing number of flotation projects are specifying columns for roughing or scavenging duties. NICICO has recently installed flotation columns operating in rougher, cleaner and re-cleaner circuits at three new copper concentrators; Miduk, Sungun and Sarcheshmeh. Miduk is probably one of the unique operations that use flotation columns in a rougher circuit. The Miduk rougher circuit comprises five CISA parallel columns. The rougher concentrate constitutes 88% of final concentrate and reports to concentrate thickener. The rougher tailings are scavenged with ten 50 m3 mechanical cells. The scavenger concentrate is then reground and cleaned in three 3.2 m columns in parallel. The cleaner tailings are scavenged in six 50 m37mechanical cells. The cleaner tailings along with the rougher scavenger constitute final tailings.In Sarcheshmeh, the cleaner concentrate is re-cleaned in a column. The column tailings are sent back to the cleaning circuit and the concentrate is reported to the concentrate thickener.This paper reviews performance details of the flotation columns utilized in rougher circuits at Miduk and compares their metallurgical performances in an industrial scale with columns at cleaning circuits for copper flotation. Practical limitations for applying the flotation columns in rougher circuits will be discussed in details.INTRODUCTIONThe use of flotation columns has grown rapidly since the first successful commercial application at Mines Gaspe, where columns were used in a cleaning circuit to float molybdenite. Early applications of columns were restricted to replacing or adding final cleaning stages in existing circuits. Columns can achieve superior cleaning as compared to conventional cells due to their ability to support a large froth depth and the use of water for washing froth. Wash water travels down through the froth and crosses the pulp/froth interface, replaces the entrained particles reporting to the froth from pulp and improve the concentrate grade."

Jan 1, 2011

By Kathleen A. Altman

"This paper supplements the information provided annually at the Canadian Mineral Processors Operators Conference regarding the education of Mineral Processors in Canada. The purpose of the paper is to provide information regarding the engineering accreditation process in the United States and the universities that offer programs in Mineral Processing and Extractive Metallurgy in the U.S.There is a critical shortage of trained Mineral Processors and Mining Engineers world wide. The Society for Mining, Metallurgy and Exploration (SME) formed a task force to evaluate the national needs for trained engineers and to track the number of engineers who graduate from U.S. universities each year. The statistical information for Mining Engineers is well-developed. The current effort is to assemble similar information regarding students who graduate with expertise in Extractive Metallurgy and Mineral Processing as well as to explore the limitations of the accreditation system in the United States and its impact on the education of Mineral Processors. The long-term objective is to develop a data base regarding Mineral Processing programs and Mineral Processing graduates that is as complete as the one that has been maintained by the Canadian Mineral Processors.INTRODUCTIONIn the United States engineering curricula are accredited by ABET, which was formerly known as the Accreditation Board for Engineering and Technology. The objective of ABET accreditation is to ensure that educational programs in applied science, computing, engineering and technology meet quality standards set in conjunction with the professional organizations that represent professionals in the industries which hire students graduating from those educational programs. For example, the Society for Mining, Metallurgy and Exploration (SME) is the lead society for accrediting Mining Engineering programs in the U.S. For Materials Science and Metallurgical Engineering programs, the lead society is The Mineral, Metals and Materials Society (TMS). SME is a cooperating society for accrediting Metallurgical Engineering programs. Cooperating societies for the accreditation of Materials Engineering include the National Institute of Ceramic Engineers (NICE), the American Institute of Chemical Engineers (AIChE) and the American Society of Mechanical Engineers (ASME)."

Jan 1, 2008

By Krishna Parameswaran

"This paper discusses energy use and conservation in the primary copper industry and illustrates eco-efficiency considerations, using select examples of practices at ASARCO LLC, an integrated primary copper producer and others in the industry that promote eco-efficiency. The World Council for Sustainable Business Development first publicized the concept of eco-efficiency at the Rio Earth Summit in 1992. Eco-efficiency is a management concept linking environmental and economic performance and is aimed at generating added value for a business through, among other things, increased resource and energy conservation and reduced environmental impacts throughout the life cycle of the product or service. This concept differs from sustainable development in that focus is only on economic and environmental factors and does not include social considerations. In the metal mining and processing context, this added value can be realized by implementing practices that promote conservation of water and mineral resources, conservation of energy, minimization of waste, reduced emissions and effluents and increased recycling. The examples from the primary copper industry used to illustrate eco-efficiency considerations include: water and energy conservation in mineral processing, adoption of flash and bath smelting processes, emission reduction and process improvement associated with fire-refining, implementation of green chemistry in electrorefining, promoting product stewardship initiatives and fostering renewable energy project on disturbed mined lands.INTRODUCTION ASARCO LLC (Asarco) was organized in 1899 as the American Smelting And Refining Company. Originally a consolidation of several lead-silver smelting companies, it evolved over the years into an integrated producer of primary non-ferrous metals, including copper, lead and zinc and associated co-products. Grupo México, S.A.B. de C.V acquired Asarco in 1999. Today, Asarco is a vertically integrated producer of primary refined copper and associated co-products such as gold, silver, molybdenum, selenium and tellurium. Asarco operates three open-pit mines and mills, two leach, solvent extraction-electrowinning (SX-EW) plants and a copper smelter in Arizona and a copper refinery in Texas."

Jan 1, 2017

By S. Schwartz, T. Bilney

"Over recent years a number of techniques have been developed as part of the AMIRA1 P9 project to represent mathematically or measure directly sub-processes occurring in flotation cells. These include the determination of:•,?a machine parameter (bubble surface area flux, Sb);•,?a froth parameter (froth recovery, Rf );•,?entrainment and drainage parameters (???and d); and•,?an ore floatability parameter (Pi).These flotation parameters allow the plant engineer to develop a model of the flotation circuit that can be used as a powerful tool to diagnose the performance of that circuit. The recently developed JKSimFloat V6 flotation simulator uses these parameters to predict the flotation circuit performance that would arise from changes in operating conditions and circuit configuration.This new flotation technology was applied to the Placer Kanowna Belle Gold Mine in Western Australia. A series of plant surveys, cell characterisation measurements and laboratory batch tests were conducted to determine the flotation circuit model parameters to be used within the JKSimFloat V6 simulatorA thorough flotation circuit analysis was then performed at Kanowna Belle using JKSimFloat V6. The recommendations that were provided by this circuit analysis have resulted in large improvements in the flotation performance at Kanowna Belle. These include a 1.3% increase in flotation gold recovery and a substantial decrease in operating costs. The analysis is still ongoing, however, the benefits already obtained from applying this technology have resulted in a US$1.3 million a year improvement to the mine."

Jan 1, 2005

By Bradford C. Wesstrom, Ricardo Parra

The Freeport McMoRan El Paso Refinery uses co-generation to produce some of its electricity and all of its steam. This paper will cover the operation of the co-generation plant natural gas turbine at a fixed RPM for blade longevity and energy output. The by-product heat from the turbine passes through boilers with additional heat from a duct burner to produce steam for the Tank House and auxiliary operations. The steam demand varies dramatically throughout the day based on unloading activities in the Tank House. The use of an automated steam control system within the El Paso Refinery will help stabilize line pressure by incrementally controlling steam consumption based on electrolyte temperature. This will minimize steam line pressure fluctuations. INTRODUCTION In the mid 1920’s the Nichols Copper Company of Laurel Hill, New York recognized the need for a modern copper refining facility in the southwest. Due to the many railroad heads, affordable power and abundant labor supply, and the close proximity to regional copper smelters in Mexico, Arizona, and New Mexico, El Paso became the logical location. In December 1928, ground was broken for the joint venture refinery between the Nichols Copper Company, Phelps Dodge, and the Calumet and Arizona Mining Company. In September 1930, Nichols Copper Company became a part of Phelps Dodge Corporation after a stock exchange. In July 1938, Nichols Division officially became Phelps Dodge Refining Corporation. In March 2007, Freeport McMoRan Copper & Gold acquired Phelps Dodge. Energy costs (electrical and thermal) are critically important in the viability of modern copper electrorefineries. The El Paso Refinery produces electricity and steam through its cogeneration system. The El Paso cogeneration facility is a natural gas, 15-megawatt facility containing five turbine generators and associated waste heat recovery boilers. The facility is divided into two phases. Phase I consists of two Allison 2.2-megawatt turbine generators. Phase II consists of three Solar Taurus 3.5-megawatt turbine generators. Presently three units in Phase II are operated. The Phase I units were purchased and installed in 1986 and the Phase II units in 1992 (Solar 1991). The facility operated at full capacity until 2003 when steam demand was significantly reduced due to decrease in cathode production and closure of the copper sulfate and precious metal operations. Phase I units were taken out of service and put on care and maintenance status.

Jan 1, 2019

By Ernie Doell, Trung Nguyen

"In early 1995 Cluff Mining commissioned a newly constructed high density tailings thickener at its Cluff Lake uranium mill. The 85 ft diameter high density thickener is one of the first of its kind in North America, and incorporates the novel paste technology in its design to produce densified (in the range of 60 -65% solids) mill tailings suitable for stable deposition in the tailings management area. This paper discusses the impetus behind the installation of such an unconventional thickener, and the many trying experiences in making it operational.IntroductionCluff Mining, a wholly owned subsidiary of Cogema Resources Inc., is the operator of a uranium mine and mill complex at Cluff Lake which is located in northern Saskatchewan. Since 1980, the company has developed and mined out several different ore bodies within the Cluff Lake region for the production of uranium concentrates, commonly known as yellow cake. Based on the known ore reserves, the Cluff Lake operations are projected to last till the early 2000's.Tailings from the Cluff Lake mill have been discharged to a tailings management area consisting of a tailings pond and two facilities for primary and secondary treatment systems. The tailings pond has an impervious bentonite lined dam, and it is divided into a solids and a liquids holding areas. Until the beginning of 1995, the mill tailings were discharged in two separate lines to the solids pond; one line carried the slurry residue of 45-50% solids (w/w) from the CCD circuit, and the other discharged raffinate tails containing less than 1 % (w/w) gypsum precipitate. Supernatant in the solids pond is treated in the primary treatment system prior to discharging to the liquids pond. Figure 1 shows the site plan of Cluff Lake tailings management area.It has been estimated that by the end of 1995 the solids pond would be filled to about 60% of its design capacity, and probably would be full before the year 2000. Therefore, Cluff Mining had to consider a more efficient tailings disposal method that could extend the service life of the existing Cluff Lake tailings management area. A high density tailings thickener was believed to be the most practical and economical system for tailings disposal at Cluff Lake mine."

Jan 1, 1996

By Jiwen Zhang

Abstract Due to the blocking nature at the crusher station, straightforward application of queuing theory cannot give realistic results on the performance of a shovel-truck-crusher system. A new queuing network-based model has been developed in which, the crusher station is formulated into an open queuing network and the whole shovel-truck-crusher system into a closed queuing network with the crusher station as a special server. To fully account for the influence of blocking, Monte Carlo simulation is first used to obtain the performance parameters of the open queuing network for the crusher station. The closed queuing network for the entire system is solved by applying the Extended Summation Method (ESUM), in which the crusher server is described by the simulation results. The model has been applied to the Yuanbaoshan open-pit coal mine to analyze its shovel-truck-crusher system and to improve its efficiency. Results indicate that the blocking at the crusher is an important factor affecting the crusher output and in turn the efficiency of the whole system, and prove that the model can realistically describe the behavior of such systems.

Oct 1, 2009

By Jiwen Zhang

Due to the blocking nature at the crusher station, straightforward application of queuing theory cannot give realistic results on the performance of a shovel-truck-crusher system. A new queuing network-based model has been developed in which, the crusher station is formulated into an open queuing network and the whole shovel-truck-crusher system into a closed queuing network with the crusher station as a special server. To fully account for the influence of blocking, Monte Carlo simulation is first used to obtain the performance parameters of the open queuing network for the crusher station. The closed queuing network for the entire system is solved by applying the Extended Summation Method (ESUM), in which the crusher server is described by the simulation results. The model has been applied to the Yuanbaoshan open-pit coal mine to analyze its shovel-truck-crusher system and to improve its efficiency. Results indicate that the blocking at the crusher is an important factor affecting the crusher output and in turn the efficiency of the whole system, and prove that the model can realistically describe the behavior of such systems.

Oct 1, 2009

By Dan Alexander, Ivan Crnkovic, Sarah Schwarz

"Several plant studies have been conducted at the Zinifex Century Mine over the past 5 years. For each of the plant studies, surveys of the zinc primary circuit were conducted, characterisation measurements for each operating cell taken, and the floatability components of the ore mapped to develop a model of the circuit. The floatability components and machine parameters were then used to simulate changes in circuit configuration and operating conditions, enabling further potential improvements in circuit performance to be identified.This paper reviews the current flotation practice at the mine, as well as various circuit changes and developments implemented by site. The application of the methodology and the evolution of the standard procedure are also discussed.INTRODUCTIONBase metals were first discovered in the Lawn Hill region of Queensland’s North West in 1869 and the first mining lease in this area was pegged in 1887 over what is now known as the Silver King vein deposit. The area encompassing these veins, which includes the Century deposit, was proclaimed the Burketown Mining Field in 1899. Exploration titles were granted to CRA in 1987, precisely 100 years after the initial discovery at Silver King, hence the name ‘Century’.Century was commissioned by Pasminco in late 1999, with the mine becoming fully operational on 1 March 2000 and the official opening taking place in April. Pasminco had bought the Century and Dugald River deposits from CRA in 1997 for A$345 million, and invested some A$710 million in bringing Century into production. Today, Century is the world’s second-largest zinc mine in terms of its output, having reached full capacity in 2003.The Zinifex Century Limited (“ZCL”) lead-zinc-silver deposit is located approximately 250 kms north-north west of Mt Isa in north-western Queensland. The deposit is a large flat-lying ore body covering an area of some 1.2 by 1.4 km, the 45 m-thick stratabound sulphide orebody is hosted within an 850 m-thick sequence of Proterozoic siltstone, shales and sandstone, amenable to open-cut mining methods. The mine has ramped up to full production delivering five and a half million tonnes of ore per annum, yielding approximately 900,000 tonnes of zinc concentrate and 90,000 tonnes of lead concentrate. Mine life is expected to be about 8 years"

Jan 1, 2008

By F. D. Aaring

"IntroductionTHE PINCHER CREEK gas condensate field, in Township 3, Range 28, and Townships 3 and 4, Range 29, West of the Fourth Meridian, was discovered in 1947 by the Canadian Gulf Oil Company with the completion of Pincher Creek No. 1 well in the Madison lime-stone of Mississippian age.This discovery was the result of a great deal of detailed seismic work in the area and is a credit to the geophysical personnel of the Company. The depth of the reservoir varies from 7,400 feet to 8,200 feet subsea, with the established water level at -8,200 feet. The predicted depth was but a scant 100 feet from that found in the discovery well, at 11, 705 feet. Since the discovery of the reservoir, three additional wells have penetrated the Madison limestone and have further verified the original •seismic interpretation of the limits of this reservoir.To date, •only a very small amount of gas has been produced from this field. Consequently, the reservoir studies that have been made so far are predominantly based on investigations of the phase behaviour of the fluid and physical characteristics of the reservoir rock. In view of the above limitations, it has been necessary to set up and perform model reservoir studies with the fluids and to recover as much core from the productive Madison limestone as possible in order that it might be analysed by conventional laboratory technique and be subjected to detailed microscopic geological examination."

Jan 1, 1952