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By K. H. J. Clarke

"ALTHOUGH nickel was not identified as a separate element until a Swedish scientist, Axel Frederick Cronstedt, did so in 17 51, its utilization dates from pre-historic times. From its humble beginnings nickel has grown in importance until, today, in our clocks, television sets, automobiles, and air-planes, in our bridges, tableware, farm implements, and the equipment which processes our food, it is constantly at our service.For convenience in assembly, data and information relative to The Marketing of Nickel will be outlined in five phases: (A) Sources, (B) Distribution, (C) Utilization, (D) Market Development, and (E) Conclusions."

Jan 1, 1960

By Roger J. Higgins

Papua New Guinea is a country on the cusp of development, struggling to find a balance between the demands of national and regional growth, landowner expectations and the maintenance of cultural identity. Ok Tedi Mining Limited is the single largest contributor to PNG?s economy, representing about 10 percent of the country?s GDP. OTML is demonstrating that business and country risk can be managed through effective, respectful partnerships with local communities. OTML?s relationships with the communities of PNG?s Western Province are multifaceted. Communities have borne the brunt of the mine?s environmental impact, yet have benefited enormously from the development that the mine has brought. Importantly, the PNG economy is now the ultimate beneficiary of more than four-fifths of the dividends from the mine, the majority of which are held in trust for long-term sustainable development projects. The paper describes how OTML works with the Western Province communities to create a secure operating environment that recognizes the people?s aspirations for development and self-determination.

May 1, 2002

By Mark Rebagliati, John Payne, Jim Oliver

Abstract-The Campo Morado precious-metal-bearing, volcanogenic massive sulfide deposits occur in a lower Cretaceous, bimodal, calc-alkaline volcanic sequence in a major northerly trending belt in the Guerrero Terrane in northeastern Guerrero, Mexico. During upper Cretaceous to Early Tertiary greenschist-facies regional metamorphism, the rocks were deformed strongly into a northeast-verging fold-and-thrust belt. Three later stages of weak deformation were dominated, respectively, by kink folds, broad warps, and extensional faults. Most deposits occur in the upper part of a sequence of felsic flows and heterolithic volcanoclastic rocks or at its contact with overlying chert and argillite-sandstone. The Reforma and El Rey massive sulfide deposits are on the overturned limb of a major, thrusted anticline, and the Naranjo and El Largo massive sulfide deposits are to the south on the upright limb of the same major fold. The La Lucha and San Rafael massive sulfide occurrences are in an upper plate to the southwest which was thrusted over the plate containing the Naranjo and El Largo deposits. In several of the deposits, Au, Ag, Zn, and Pb are concentrated near the stratigraphic top, and Cu is concentrated near the stratigraphic base. Major minerals are pyrite, quartz, ankerite, sphalerite, chalcopyrite, and galena. Minor minerals are tennantite-freibergite, arsenopyrite, and pyrrhotite. Gold and Ag occur in argentian gold, and Ag also occurs in tennantite-freibergite. The cumulative inferred resource of massive sulfide for the Reforma, Naranjo, El Rey, and El Largo deposits exceeds 30 Mt, with the latter two deposits incompletely delineated. Underlying pyrite-quartz stockwork zones contain chalcopyrite, chlorite, and sphalerite. Hydrothermal alteration minerals in the stratigraphic footwall are pyrite, quartz, chlorite, ferroan dolomite, and ankerite. In the stratigraphic hangingwall, hydrothermal alteration minerals are sericite, calcite-dolomite, and lesser clay minerals and quartz. The deposits belong to a low-sulfidation, volcanogenic massive sulfide system formed in a subaqueous environment, and are of the bimodal, siliciclastic type.

Jan 1, 1997

By Mark Rebagliati, John Payne, Jim Oliver

The Campo Morado precious-metal-bearing, volcanogenic massive sul?de deposits occurin a lower Cretaceous, bimodal, calc-alkaline volcanic sequence in a major northerly trending belt inthe Guerrero Terrane in northeastern Guerrero, Mexico. During upper Cretaceous to Early Tertiary greenschist-facies regional metamorphism, the rocks were deformed strongly into a northeast-verging fold-and-thrust belt. Three later stages of weak deformation were dominated, respectively, by kink folds, broad warps, and extensional faults. Most deposits occur in the upper part of a sequence of felsic ?ows and heterolithic volcanoclastic rocks or at its contact with overlying chert and argillite-sand-stone. The Reforma and El Rey massive sul?de deposits are on the overturned limb of a major, thrusted anticline, and the Naranjo and El Largo massive sul?de deposits are to the south on the upright limb of the same major fold. The La Lucha and San Rafael massive sul?de occurrences are in an upper plate to the southwest which was thrusted over the plate containing the Naranjo and El Largo deposits. In several of the deposits, Au, Ag, Zn, and Pb are concentrated near the stratigraphic top, andCu is concentrated near the stratigraphic base. Major minerals are pyrite, quartz, ankerite, sphalerite,chalcopyrite, and galena. Minor minerals are tennantite-freibergite, arsenopyrite, and pyrrhotite. Goldand Ag occur in argentian gold, and Ag also occurs in tennantite-freibergite. The cumulative inferred resource of massive sul?de for the Reforma, Naranjo, El Rey, and El Largo deposits exceeds 30 Mt, with the latter two deposits incompletely delineated. Underlying pyrite-quartz stockwork zones contain chalcopyrite, chlorite, and sphalerite. Hydrothermal alteration minerals in the stratigraphic foot-wall are pyrite, quartz, chlorite, ferroan dolomite, and ankerite. In the stratigraphic hangingwall, hydrothermal alteration minerals are sericite, calcite-dolomite, and lesser clay minerals and quartz. The deposits belong to a low-sul?dation, volcanogenic massive sul?de system formed in a subaqueous environment, and are of the bimodal, siliciclastic type.

Jan 1, 1997

By Caroline B. Chapleau, Mélanie Proulx, Claude Bazin, Gaétan Lavoie

"Quebec Cartier Mining operates a pelletizing plant in Port-Cartier, QC. Grinding, agglomeration and pellets induration are the three main steps in the preparation of iron oxide pellets. In 1998, following different recommendations, the company increased the speed of one of its ball mill in order to increase the grinding efficiency of the machine. As expected, the increased speed lead to an increase of the power draught, which did not produce the expected increase of fineness of grind, neither its allows to increase the mill throughput. The change of behaviour of the mill could hardly be understood by comparison of discharge size distribution at initial and modified mill rotation speed. On the other hand, the use of the selection function from a population balance model provides an insight of the changes that occurred in the mill. This paper reviews the various steps required for the estimation of a grinding mill selection function. Results of the calibration to Quebec Cartier grinding mills show that the increase in the mill speed leads to higher rate of breakage of coarse particles, at the expenses of less efficient breakage of medium and fine size particles. In the case of the studied mill, breakage of coarse particles was probably not the critical step of the mill operation. INTRODUCTIONOre size reduction is the major energy consumption step in any mineral processing operations (Austin et al., 1984). Size reduction is required to either liberate valuable minerals from the gangue minerals in which they are imbedded, or to increase the specific surface of the ground material. Plant engineers continuously face the challenge to find grinding machines, operating conditions or grinding circuit flowsheet configurations that could improve the size reduction process at lower energy or m6dia consumption."

Jan 1, 2000

The importance of understanding the behaviour of cemented paste backfill (CPB) within the framework of the effective stress concept is highlighted in this paper. Only through an understanding built on this concept can problems such as barricade loads, the rate of consolidation and arching, be fully understood. The critical importance of the development of stiffness during the hydration process, and its impact on factors such as barricade loads, is used to illustrate why conventional approaches that implicitly ignore the effective stress principle are incapable of capturing the essential components of CPB behaviour.

May 1, 2007

By Francis Chartrand

The Kwyjibo deposit is an iron oxide Cu-REE-F-Mo-Au mineralization of Mesoproterozoic age located in the Grenville Province approximately 120 km NE of Sept-Îles, Quebec (Figure 1). Occurring along the SE margin of the Canatiche granitic complex, the deposit is composed of several polymetallic showings that are related to different textural facies of magnetite. The mineralization process at Kwyjibo is complex, and is divided into Early Granitophile, Magnetite, Main Polymetallic and Specular Hematite stages (Cayer et al., submitted for publication). The Main Polymetallic stage, comprising chalcopyrite, pyrite, fluorite, molybdenite and REE-bearing minerals, is superimposed on pre-existing magnetiterich rocks. Discovered by SOQUEM Inc. in 1993, the Kwyjibo deposit shares many characteristics with other hydrothermal polymetallic iron oxide deposits around the world. Foose and McLelland (1995) suggested that this class of mineralization could occur in the Grenville Province. However, only a few polymetallic occurrences are known to be associated with low-Ti iron oxide deposits in the Grenville. Kwyjibo is one of the most significant examples of a polymetallic iron oxide deposit to have been found in the Grenville Province to-date.

May 1, 2003

By R. D. Lawrence

"Comparable transaction analysis is the best known of the market approaches to valuation of exploration-stage mineral properties. The analysis of option and farm-in agreements can also provide useful guidance to valuators. While such approaches can be distorted by incomplete analysis, market-based methods are capable of providing consistent, credible results when carried out carefully with due consideration paid to all factors which buyers and sellers consider when dealing in the real market. IntroductionMineral properties without defined resources present one of the most challenging tasks to the mineral valuator. This paper will concentrate on market-based approaches to valuation of such properties. Other authors at MM2000 presented papers on cost and income approaches. Sorentino (2000) also provides a useful overview with some provacative commentary on methods.Market based-approaches are based on the principle of substitution and include such techniques as: comparable transaction analysis (sometimes referred to as sales comparison analysis); farm-in commitment (or option agreement) analysis; rules-of-thumb; and comparable market value analysis.Are there any valuation standards available to assist the valuator? In Canada there are none that apply to the valuation of mineral assets or securities. This problem is being addressed, at least in part, by the CIMVal Committee of the Canadian Institute of Mining, Metallurgy and Petroleum (CIM)1. Further, the recently established Canadian Association of Mineral Valuators will be giving consideration to the adoption of valuation standards."

Jan 1, 2002

By Derek H. C. Wilton

"The Nain Province (NP) of northern Labrador is a >600 km long by =100 km wide Archean craton that has undergone relatively little mineral exploration until economically signifcant concentrations of orthomagmatic nickel sulphide were discovered by Diamond Fields Resources (DFR) at Voisey’s Bay. Due to the great time span between crust formation andfnal intrusive activity (ca. 3.9 Ga to 1.27 Ga),there were, however, numerous metallogenic events within the NP.The NP was intruded by the ca. 1.3 Ga to1.2 Ga Nain Plutonic Suite (NPS) composite anorthosite-granite complex. The NPS dividesthe NP into the southern Hopedale Block (90 km by 150 km) and the northern SaglekBlock (375 km long by =50 km wide). These two blocks appear to represent two distinct Archean cratonic nuclei, each with its own distinct metallogenic history. The NPS is a coalesced assemblage of composite intrusions which include anorthosite, troctolite, norite, gabbro and granite.The Hopedale Block contains the Hunt River and Florence Lake greenstone belts, and the Weekes Amphibolite which represents remnantsf the older Hunt River greenstone belt. Geologically, these belts have some potential to host komatiitic Kambalda-style nickel, volcanogenic massive sulphide (VMS) and meso -thermal lode gold mineralization. The unconformity between Paleoproterozoic cover sequences and the trondhjemite-tonalite-granodiorite (TTG)suite which engulfed the greenstones was the locus for lead-zinc-bearing quartz-carbonate veins. Minor fracture-hosted uraninite showings are also present in the TTG.The Saglek Block is a high-grade gneissterrane with deformed Archean supracrustal sequences but no greenstone belts. Within the gneiss are variably-sized enclaves that range in composition from anorthositic to ultramafic; some of these latter xenoliths contain abun-dant fuchsite. There are also three small anorthositic to ultramafic meta-igneous complexes present in the gneiss near Okak Bay.Some Archean meta sedimentary and maficgneiss supracrustal sequences contain iron-oxide and sulphide members. The sulphide-bearing Tasiuyak parag neiss defines the cra-tonic suture between the NP and Churchill(Rae) Province. Along the cratonic suture between the NP and Churchill Province from Ramah Bay north are remnants of the Archean(or Paleoproterozoic) Hutton Anortho site Suite. Ultramafc layers within the suite contain chromite and elevated Ni values.Three ca. 2.0 Ga supracrustal sequenceswere deposited in small fault-bounded basins within the NP. The Snyder Group contains pyrrhotitiferous massive sulphide horizons. TheMugford Group contains SEDEX-like massive sulphide blocks in a debris fow and ultramafic sills with unusual PGE concentrations; alaskitic granite cutting basement gneiss to the group contains stockwork-like pyritiferous quartz veins. The Ramah Group contains numerous MVT-style zinc-lead sulphide occurrences.The Reid Brook Intrusion of the NPS contains enormous and high-grade nickel-copper-cobalt massive sulphide bodies at the Voisey’s Bay deposit. Exploration in the northern portions of the NPS in 1995 has indicated the presence of other potentially economic nickel sulphide horizons."

Jan 1, 1996

By A. Ingelson

Conflict over mineral development and its impacts on indigenous peoples occurs in many countries around the world. Canada, Bolivia and Peru have experienced mine development for centuries in areas where indigenous communities have been and continue to be affected by the mining industry. On a global basis the mining industry continues to face the challenge of implementing meaningful consultation programs with indigenous peoples. Many governments around the world have adopted sustainable development as a policy and one important element of sustainable development is minimizing social conflict. John Moffet and Francois Bregha (Moffet & Bregha, 1996), in their analysis of the role of law reform in promoting sustainable development, noted that stakeholder participation can reduce this type of conflict. Social conflict can result in expensive litigation and costly project delays for mine developers. Meaningful consultation with indigenous peoples in areas where mine development is proposed can be a critical factor in securing a social licence to operate. A report released by the United Nations in 2005, outlined the elements of a concept called ?free, prior informed consent? (FPIC) that promotes more sustainable development. FPIC provides that mineral exploration and mining should not proceed unless the mining company has secured the consent of the relevant indigenous group(s). This paper employs a comparative approach to evaluate the extent to which three active mining nations, Canada, Bolivia and Peru, require consultation with indigenous residents and adhere to the principle of FPIC. The comparative approach assists in the identification of those consultation elements in the legal regimes of each country that can minimize social conflict in mineral exploration and mine development and therefore contribute to more sustainable development. First, we examine the legal requirements to consult with and accommodate indigenous communities in Canada, a country with a long history of mineral development over a large geographic area that has entrenched in its Constitution the protection of indigenous peoples? rights. We then turn to an analysis of Bolivia, one of the most indigenously conscious mining jurisdictions that has followed the Canadian lead in entrenching constitutional protection for indigenous peoples. Third, the approach to consultation with indigenous peoples in Peru, a nation that has not adopted the Canadian and Bolivian approaches to constitutional protection of indigenous peoples rights, is considered.

Aug 1, 2013

By Alan D. Curtis

A standard planning block model for Phelps Dodge North America Operations has been developed to improve mine planning efficiency and performance in a skill starved environment. The model saves time on software management and training, consolidates data and standard information/output, enhances evaluation and strategic process, and improves communication between sites.

May 1, 2007

By A Palynchuk

The development of welded pipe has paralleled the general industrial development and, in particular, that of the petroleum industry. The petroleum industry's need for high-grade, economical pipeline material to make many 'of its projects feasible has been a significant factor in the development of light-wall, high-grade welded pipe. The modern welding processes, such as high-frequency, electric resistance, flash, submerged arc, etc., have some basically different characteristics. The modern high-frequency weld mill is a complex of specialized equipment that is integrated into a production unit. Each component in the unit performs a specific function in the production process. Quality control must be built into the process on an operating basis and, to maintain the quality required for pipeline standards, must be more than a policing operation. The further development of the welded pipe industry will be determined by changing and increasing demands. The technical and economic views and requirements that will influence the development have to be resolved.

Jan 1, 1964

By Richard Burt

"In seeking to supply the ever increasing needs for raw materials, the mining industry has been required to develop lower grade resources in increasingly remote regions of the world. This has resulted in the extension of many frontiers, both technologically and geographically.The accent of mineral processing research over the last few decades has been to “do existing things better”. There have been many breakthroughs in equipment and processes; however in general the accent has been to increase capacity of existing unit processes, often by orders of magnitude, or to refine the process itself by basic research and development. This has lead to added sophistication, enabling the process engineer to maintain optimum performance of his equipment while reducing the cost, and the amount of labour needed to operate the plant.While much of the increased requirement for resources is handled by the development of ever larger, lower grade orebodies, a significant portion still comes from the small miner - even the artisanal miner - operating in remote and often politically sensitive parts of the world. For them, innovation and simplicity are the keys, not sophistication.The tension between sophistication and simplicity - or research and reality - is specially evident in the area of gravity concentration of rare metals, such as tin and tantalum. This paper looks at this tension, primarily from the eyes of an operator and seeks to put into perspective the two paradigms."

Jan 1, 1999

By Gregg Hodges, Fred Schoenbrunn, Steve Slottee, Chad McCleary

"In December, 1999 Stillwater Mining Company (SMC) commissioned a new paste /cement backfill plant to supplement the existing sand backfill system for the cut and fill mining operation at it’s Nye, Montana mine. The new plant uses the Baker Process Deep Cone TM Paste Thickener to thicken the total concentrator tailings from 30% solids slurry to a 71% solids paste. This paper describes both general paste formation concepts and the evolution of the SMC paste plant operation from original design criteria, through problem solving and plant modifications, to the operation of the existing plant.Although the original process design was not effective for consistently producing and delivering acceptable paste to the stopes for backfill, SMC was able to make the mechanical and process modifications which allow the plant to now produce and deliver an acceptable product to the stopes. Ongoing test work is targeted at increasing the pumping range of the system, increasing the paste solids concentration from the Deep Cone Paste Thickener and reducing the operating and maintenance costs of the system.INTRODUCTIONThe authors would like to thank both Stillwater Mining Company (SMC) and Baker Process for their assistance in the preparation of this paper. Stillwater Mining Company chose not to participate directly in this paper due to time constraints, but was very helpful in answering questions concerning their approach to problem solving and specific details with regard to engineering criteria.This paper will begin with a general review of the technical and mechanical concepts in paste formation and then focus on the overall design, start-up and problem solving process for the paste backfill operation at SMC’s mine and concentrator near Nye, Montana."

Jan 1, 2001

By M. J. H. Ruscoe

"The circulation wear rates of pure nickel, cupronickel and nickel-plated-steel coins were measured and found to be in the ratio 1:3:1 . The relative wear rates of nickel and cupronickel coins were similar to those reported in earlier studies, and the circulation wear data for nickel were used as a reference in laboratory wear tests. A correlation between circulation wear rates and laboratory wear rates formed the basis for a prediction of service life using relief legibility as an 'end of life' criterion. This criterion was determined to be an average surface thickness loss of 12 um. The surf aces of nickel and Nickel-Banded-Steel (N-B-STM) coins were observed to harden both in circulation and in the laboratory tests at a rate of approximately I VHN/year of actual or simulated service life. It was also observed that the laboratory wear rate of N-B -S coins increased as nickel cladding thickness increased and this effect was attributed to differences in surface hardness.Wear test results are also reported for the new Canadian dollar coin material which shows a better wear resistance than pure nickel. IntroductionThe subject of coinage wear has a long history, and a number of studies have been published, concerned both with the measurement of circulation wear rates and with accelerated laboratory tests to simulate the behaviour of coinage materials in service. As early as 1803, wear tests were conducted by Hatchett on gold coinage using various types of vibratory and tumbling machines». These tests were commissioned by King George III of England who was concerned about the wear of gold coins in circulation.Early in this century, Adrian performed laboratory tests that showed that the wear rates of cupronickel 75/25 and nickel coins were in the ratio 3:1 and this ratio was later confirmed in laboratory tests reported by Daeppen and Zurrerw, The latter authors also weighed cupronickel and nickel coins that had been in circulation for various times and observed the same 3: I ratio. There was further support from Tylczak and Blickensderfer who reported significantly higher abrasive wear rates for cupronickel compared to nickel, when rubbed against sand paper."

Jan 1, 1988

By R. T. Jones

The largest known platinum group metal (PGM) deposit in the world is the Bushveld Complex in South Africa, with the Great Dyke in Zimbabwe also being one of the biggest. It is therefore not surprising that the majority (just over 5 million troy ounces or 156 metric tons per annum) of the world's platinum is produced in Southern Africa. Primary smelting of ore concentrates is carried out in that region by five companies, namely Anglo Platinum, Impala Platinum, Lonmin Platinum, Northam Platinum, all of South Africa, and Makwiro Platinum in Zimbabwe. The only other primary smelter of platinum group metals is Stillwater Mining of Montana, USA, although very significant quantities of PGMs are produced as co-products by Norilsk Nickel of Russia. Smaller (but still significant) quantities of PGMs are produced by Falconbridge and Inco of Canada, also as co-products from nickel sulphide smelting. There are many similarities between PGM smelting and nickel sulphide smelting, and the range of technologies in use includes six-in-line rectangular electric furnaces, three-electrode circular AC furnaces, Peirce-Smith converters, and Anglo's ACP (based on Ausmelt technology). PGMs are also recovered from residue materials using DC arc furnace technology.

Jan 1, 2005

By Fidelis T. Suorineni

The Ashanti mine, located in Obusai, Ghana, West Africa, has been in production for over 100 years, and is currently the second largest single gold producer in Africa. The mine covers a concession area of 434 square kilometers with four main ore types: the quartz vein type, disseminated sulphide type, supergene sulphides and transition ore, and granitoids stock works (visible gold and quartz veinlets). Various mining strategies and methods have been employed for the mining of the narrow-vein ore at Ashanti. In recent years, the mine owner: Ashanti Goldfields Company Ltd. has embarked on a mine-wide expansion program to boost production to a target of one million ounces per annum. With the rapid depletion of its high-grade ore, a suitable mining method was required to produce a high tonnage at low cost to meet production objectives. This paper discusses how the Ashanti mine applied Canada experiences in mining technology to boost production, and the impact that the differing geological settings between the two countries had on the stope performance at the Ashanti operations. Experience developed at the Ashanti mine led to innovative modifications for stope layout and design methods in relatively poor ground conditions.

Oct 1, 2001

By A. I. Collins, D. Danninger

Newmont has installed advanced control and online optimization on the dry grinding circuit and both roasters on its Carlin Trend refractory ore treatment plant. Subsequently, Newmont has developed a master plan for institutionalizing advanced control and optimization on all its processing units. Newmont is committed to a program of applying advanced control and optimization from crushing of ore to pouring of gold. This paper describes Newmont's experience with implementing advanced control and optimization and the benefits received. In addition, identification of advanced control and optimization opportunities and their economic justification is discussed.

Jan 1, 2005

By Michael Harley, E. Guy Charlesworth

"Abstract - Bedding-parallel thrust-hosted gold veins are developed in the Sabie-Pilgrim's Rest goldfield, eastern Transvaal, South Africa. The reefs display a complex history characterized by temporally and spatially overlapping events of similar mineralization and deformation. Recognition of the episodic reactivation of these low angle (5° to 10°) thrust faults implicates high fluid pressures (equalling or exceeding lithostatic pressures). Geochemical constraints limit the amount of fluid-rock interaction and the occurrence of transgressive mineralization within the Archaean granitoid basement suggests that the high pressure fluids originated at depth beneath the Transvaal Basin.Similarities exist between gold deposits of Sabie-Pilgrim's Rest and Telfer, Western Australia as well as Passagem de Mariana, Minas Gerais, Brazil. All deposits are sub-parallel to the enclosing bedding which is shallowly inclined. Furthermore, they are also hosted by contractional deformational structures and are clearly epigenetic in origin."

Jan 1, 1994

By J. Moyes

The Intec Process is a generic process for the production of pure base metals and precious metals from sulphides concentrates derived from copper, nickel, zinc and lead ores. The development program for the Intec Process initially focussed on the treatment of copper concentrates, (the ?Intec Copper Process?), and more recently of zinc concentrates, (?the Intec Zinc Process?). Developed and proven in Sydney, Australia at a cost of US$15m over the last ten years, the Intec Copper Process is now ready for commercial application. The knowledge gained during the development of the Intec Copper Process has been applied to the Intec Zinc Process, which utilises the same basic chemistry to produce high purity zinc ingot from metallurgically complex zinc sulphide concentrates containing lead, copper, iron, silver and gold. The demonstrated ability of the Intec Zinc Process to treat low grade mixed zinc/lead/copper concentrates, including those with high iron and manganese levels, holds out the real prospect of overcoming major metallurgical hurdles that have long affected the zinc industry. The Intec Zinc Process consists of the three consecutive circuits of leaching, purification and electrowinning. The leach circuit is of single stage configuration with a series of reactors to which concentrate and lixiviant are fed. Purification consists of cementation and precipitation by pH adjustment. Electrowinning employs an electrolytic cell very similar in design to that of the Intec Copper Process, but differs in that a conventional plate cathode is produced. During electrowinning, the same mixed halide species (BrCl2 -, HalexTM) that is integral to the Intec Copper Process is generated in solution at the anode and exhibits powerful leaching characteristics capable of directly leaching the sulphide concentrate feed. The need to roast the concentrate prior to leaching, as is practised in the conventional Roast/Leach/Electrowin (RLE) process, is thus eliminated whilst a range of by-products (notably lead, copper and precious metals) can be extracted in the simple, single-stage leach. This paper describes the Intec Zinc Process; the technology, predicted economics and its environmental aspects.

May 1, 2002