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By Corby G. Anderson

"Laboratory testing, plant optimization, and the interpretation and application of metallurgical technologies can be tedious, time consuming and costly. This paper outlines the use of proven statistical design of experimentation software for rapid laboratory testing and optimization of operating plants with limited representative sample utilization. This results in less costly required testing, a more thorough understanding of results and the ability to simultaneously optimize several variables and outcomes at once. At the Center for Advanced Mineral and Metallurgical Processing (CAMP), this testing methodology has been used successfully in many metallurgical development and plant optimization projects thereby confirming its real world utility and application. Accordingly, several applied examples in flotation and hydrometallurgy will be outlined in this paper. This will include flotation testing of a copper gold ore, flotation testing of a copper, cobalt and gold ore, optimization of an industrial hydrometallurgical jarosite circuit and optimization of industrial nitrogen species catalyzed pressure leaching of a copper enargite concentrate.INTRODUCTIONWhile flotation technology is now 100 years old, the testing, interpretation and application of lab results can be tedious, costly and time consuming requiring extensive sample collection and preparation. In addition, recent applications like hydrometallurgical pressure leaching and associated unit operations, such as precipitation, still remain more of an art than a quantifiable science. This paper will elucidate the application of STAT-EASE Design-Expert software to minimize required laboratory testing while rapidly optimizing multiple results and outcomes in a statistically valid manner. The STAT-EASE program is based on proven design of experiment fundamentals. In this paper, the real world application of this methodology for lab testing, plant optimization and process development will be elucidated."

Jan 1, 2006

By Phillip Cancilla, Daniel Roy, Frank Rosenblum

"The manual moisture determination methods employed today by mineral processing plants falls short in providing timely information required for automation control. The costs associated with transporting and handling concentrates still represent a major portion of the overall treatment price. When considering the cash flow of a mining operation, that is governed by both the smelter contract, with moisture penalties and the quantity and quality of the concentrates shipped, an efficient method of on-line moisture content would be a welcome tool.A novel on-line determination system for ore concentrate moisture content would replace the normally tedious classic manual procedure. Since the introduction of microelectronic-based control systems, operators have strived to reduce the treatment costs to the minimum therefore a representative and timely determination of on-line moisture content becomes vital for control set points and timely feedback. Reliable sensors have long been on the “wish list” of mineral processors since the problem has always been that you can only control what you can measure. Today, the task of moisture determination is still done in the classical technique of loss in weight by uncontrolled procedures. These same methods were introduced in the earliest base metal concentrators. Generally, it is acceptable to have ore concentrate moisture content vary within a range of 7 to 9%. Many times, delays in manually achieving reliable feedback on the moisture content results in the moisture varying from 5 to 12% before corrective actions can be made.This paper first reviews the traditional and widely available methods for determining moisture content in granular materials by applying physical principals and properties to measure moisture content. All methods are in some form affected when employed on mineral ore concentrates. This paper describes a unique and promising on-line moisture sensor in two mineral processing applications, which not only automates the tedious tasks but also results in reliable moisture feedback that can be used in the optimization of the de-watering process equipment such as pressure or vacuum filters and fuel-fired driers. Finally, two measurement applications will be presented to indicate the usefulness and to summarize the measurement requirements for the proposed method of employing drag force and mechanical properties of the material itself to determine the moisture content."

Jan 1, 2001

By G. Girard, A. Larouche, J. Colbert, G. Doyer

"The Direct Chill (DC) casting process uses water to extract heat from molten aluminium and helps to control the solidification process. Many factors such as the water flowrate, water distribution around the mould and water impingement angle have significant impacts on the solidification process. It has been noted that the chemistry variation of the cooling water is also an important factor that has a major impact on the presence of defects on the ingot. A significant change in the water quality can produce defects on the ingots such as cracks, bleedouts, or runouts. Understanding the impact of water quality variation on ingots is therefore essential to ensure good ingot production and reduce defects. This paper aims at describing a new approach to follow the variations of process water quality over time. It is an original and innovative method, which is still under progress. A water quality and stability index (WQSI) is under development to evaluate changes in the water composition based on water physico-chemical parameters. The index is calculated by comparing each of the actual parameters with historical values previously modeled by a statistical law. It is a dimensionless number having an adjustable weight factor for each parameter. The positive or negative contribution of each parameter, with respect to the water cooling capacity, is taken into account to calculate the WQSI. The current selection of parameters is based on knowledge from the literature as well as on empirical experience. When the developed tool will be mature, it could be used to track water variations upon time and anticipate problems, enabling proactive actions to ensure good ingot production.INTRODUCTIONFor many years, the impact of water chemistry on heat transfer, during DC casting, has been of great interest in the aluminum industry. Several papers have been published to demonstrate the correlation between water chemistry and heat transfer (Yu, 1985), (Gildemeister, 2014). Although numerous studies do present the effects of water parameters (i. e. hardness, conductivity, oil, and grease…) on cooling capacity under controlled experimental conditions, they do not reflect the strong interactions between the parameters and variations present in a casting center. Wells and Cockcroft also demonstrated that laboratory based studies are not fully representative of real heat transfer in an industrial casthouse, there are too many factors involved (Wells, Li, & Cockcroft, 2001). In this context, it becomes very difficult to obtain a quantifiable relationship between the capacity of water to cool the ingot and ultimately the performance of the cast."

Jan 1, 2016

By Scott Honan, Tassos Grammatikopoulos, Mike Johnson, Kelton Smith, Niels Verbaan, Ernesto Bourricaudy, Eric Larochelle, Rick Sixberry

"NioCorp is developing the niobium/scandium/titanium Elk Creek carbonatite resource deposit. The carbonatite phase contains significant niobium (0.71% Nb2O5), titanium (2.68% TiO2) and scandium (72 g/t) and is composed predominantly of calcite, dolomite and ankerite. Niobium is mostly (80%) contained in the pyrochlore and the balance in various Fe-Nb-Ti oxides, which also host most of the titanium. Scandium is distributed homogeneously throughout the ore mineral assemblage. The process flowsheet recovers separate niobium, titanium and scandium products. Scandium is extracted from whole ore hydrochloric acid leach solutions through solvent extraction, and is further refined through a re-leach and precipitation process. Scandium leach residues are treated with sulphuric acid to recover separate niobium and titanium precipitates. Both hydrochloric acid and sulphuric acid reagents are recycled within the flowsheet. This paper will discuss key bench and pilot test results (focusing on the scandium flowsheet) and will present a conceptual flowsheet developed by the project team for NioCorp at SGS Minerals.INTRODUCTION NioCorp is developing North America's only niobium/scandium/titanium project. The Elk Creek project is located near Elk Creek, Nebraska, and is the highest grade niobium project in North America and the largest prospective producer of scandium in the world. These elements are unique and valuable superalloy materials that are strategic and critical to many industries and national defense technologies. The project includes the Elk Creek Carbonatite (the Carbonatite) that intruded older Precambrian granitic and low to medium grade metamorphic basement rocks. Both the carbonatite and Precambrian rocks are interpreted to be unconformably overlain by approximately 200 meters (m) of Paleozoic marine sedimentary rocks of Pennsylvanian age. As a result of this thick cover, there is no surface outcrop within the Project area of the carbonatite, which was identified and targeted through magnetic surveys and confirmed through subsequent drilling. The available magnetic data indicate dominant northeast, west-northwest striking lineaments, and secondary northwest and north oriented features that mimic the position of regional faults parallel and/or perpendicular to the Nemaha Uplift."

Jan 1, 2017

By Mohamed Ourriban, Stéphanie Somot, Éric Proulx, Jean-Sébastien Marois, Marjolaine Drouin, Paul Blatter, Ahmed Bouajila, Claude Gagnon

"The mining industry has to face increasing restrictions concerning the use of fresh water in Québec and throughout the world. Increasing recirculated water usage could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have a negative impact on mineral processing operations, thereby limiting the incentive for sustainable development initiatives. As a first step into selecting and testing remediation strategies, one of which being blending local waters, a mapping of process water quality (inorganic and organic fractions) allowed to locate zones in an industrial case study where fresh water is introduced into the circuit and to detect dissolution and precipitation zones. A complementary hydro-geochemical modeling study on water blends was also performed showing encouraging results towards the objectives of the project.INTRODUCTION The industry has to face increasing restrictions on the use of fresh water in Québec (Quebec Government, 2009) and throughout the world (Brown, 2003; UNESCO, 2006). The cost for the use of fresh water and for water management is highly variable and case-dependent (from 0.2 to up to 7 million dollars/year according to available private estimations, excluding the capital expenditure). It may be, or may become, significant for any plant; thus, risk assessment is of concern here. Using recirculated water could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have some positive and negative impacts on mineral processing operations (Janssen, 2003; Johnson, 2003; Rao and Finch, 1989). Negative impacts could limit the incentive for sustainable development initiatives. Water management strategies at mineral processing sites are supported both by a strategic plan and a water management plan. The strategic plan includes legal aspects, investment costs, potential benefits and various risk levels (Corder and Moran, 2006; Côte et al, 2006; Evans et al., 2006; MacIntosh and Merritt, 2003; McLellan et al., 2008; Merritt and MacIntosh, 2006; Robinson and Keddie, 2006; van Beers et al., 2007a; van Beers et al., 2007b; van Berkel, 2007). In practice, the strategic plan evaluates technical possibilities and costs of various scenarios, such as for example: bringing fresh water to the plant or recirculating waters, or using blends of both. Two important factors to consider in order to enhance the future production efficiency and to minimise risks are: the durability and the stability of the resource, both from quality and quantity points of view."

Jan 1, 2012

By Timo Niitti, Antti Rinne, Janne Turunen, Sami Grönstrand

"This paper describes novel methods to enhance the flow dynamics of a mechanical flotation cell that can be applied to an existing installation. There are several reasons to alter the flow dynamics. The most common motivation is to improve the metallurgical performance of the cell, for instance, to improve the flotation recovery in particle size ranges that are normally difficult to recover.The flow dynamics enhancements are associated with the geometry of the rotor-stator area and additional features in the tank. The rotor-stator area has been modified to provide more concentrated turbulent kinetic energy or respectively more pumping efficiency with less attrition to the slurry. The tank can be fitted with various geometrical features, aimed to create a desired particle suspension profile. Depending on the targeted particle size range and application, badly selected or designed features can also have a negative effect on the metallurgical results.Besides new flotation equipment, the enhancements can be applied to existing flotation cell installations, thus enabling improvements in the mixing profiles, solids suspension, tank sanding and metallurgical performance of operating flotation circuits. Results of several tests carried out in existing plant operations are presented, concerning both flow variables and metallurgy.The common factor to above-mentioned enhancements is the use of modern computational fluid dynamics tools in the design phase, as well as the validation of the obtained CFD results in laboratory and production scale. Validated variables include mixing profile, power draw and local air hold-up.The paper demonstrates the effects of various flow geometries on the mixing profiles and metallurgical results of existing mechanical flotation cells. It shows how modern computational fluid dynamics analysis can be used to screen and select different approaches before carrying out costly trial-and-error experiments in plant scale."

Jan 1, 2006

By Art Carino

"The McClean Lake operation is located in the Eastern Shore of the Athabasca Basin in northern Saskatchewan some 700-air kilometers north of Saskatoon. It is operated by Cogema Resources Inc., the major share holder of the joint venture consisting of Cogema Resources Inc., Denison Mines Limited and OURD, a consortium of Japanese utilities.The JEB mill is the first uranium mill to be constructed and licensed in North America within the last 15 years. The mill uses conventional uranium unit process but employs innovative techniques unique to the JEB mill.This paper presents brief descriptions of the various unit processes, the innovations and the commissioning strategies developed to achieve the designed production capacity in the shortest possible time.INTRODUCTIONThe McClean Lake ore body was discovered in 1979, followed by the discovery of the JEB ore body in 1982. From 1985 to 1990, a cluster of deposits named Sue A, Sue B and Sue C were discovered. Environmental Impact Assessment (EIS) of the McClean Lake project began in 1990 under a joint federal-provincial process. Following the public hearings in 1993, the governments gave approval to proceed with the construction of the project, subject to fulfilling licensing requirements.The McClean Lake ores are located in the uranium-rich geological region of Saskatchewan known as the Athabasca Basin, 700 air kilometers north of Saskatoon. The JEB mill is located near the mined out JEB open pit that is now used as the tailing depository.The approved mill has a production capacity of 6,000,000 pounds of U3O8 annually and is capable and licensed to process JEB, Sue A, Sue B, Sue C, McClean Lake, and Midwest Lake deposits. Although the EIS has been approved, Mining of the Midwest Lake deposit has not been approved at this time."

Jan 1, 2001

By Jonathan Peck, Jim Gray

"While the mine developer looks for bigger and better orebodies in countries offering lower risks to development capital, the opera-tor of existing mines is looking for bigger and better ways to use his existing resources. Mining operations today utilize a variety of stand-alone systems for planning and managing their operations. In both small and large mines, payroll, accounting, inventory, planning, and engineering requirements are met using a combination of manual and computer-based systems.Technical advances and new enabling technologies are changing how mines are doing business. PC-based systems are allowing small operations to join the larger mines in using advanced computer-based systems. Advanced monitors are being used in maintenance to track, predict and correct the health of production equipment. Production monitoring systems are used to measure the performance of operating equipment and personnel in real time. This detailed information on how much, where, when, and by whom is being used for proactive management and planning. Ultimately, this information can be used to optimize and control the machines’ activities, eventually leading to robotic and autonomous operation of mining equipment.As the use of technology increases in mining, specific information objectives are being met but other problems are being created. The life cycle of technology is small, and as current systems are replaced by newer ones, integration problems and additional end-user training are created. In addition, onboard monitoring systems can create large volumes of data, data which are frequently archived without being analyzed. Mine operators are also duplicating efforts applying new technologies in an effort to be more competitive, but in doing so are creating interfaces which are only compatible with their own facilities. As system development moved from the centralized mainframe computer to the PC environment, the fragmentation of these systems became more pronounced.To efficiently continue in adapting and utilizing advancing technology, the mining industry needs to develop a system architecture that readily integrates as many sub-systems as possible. This will provide a framework for existing system integration and design guide-lines for future development. The Total Mining System (TMS) concept will allow a network of stand-alone functional modules to be readily integrated with minimal effort. This paper will discuss some of the current technologies cur-rently in use in some surface mine operations.In addition, a description of the information system and communications requirements that will be needed to integrate these components in the future, will be discussed."

Jan 1, 1996

By John G. Henning

Unplanned ore dilution has a direct and large influence on the cost of a stope, and ultimately on the profitability of a mining operation. This paper presents results of a study on the influence of a variety of factors on ore dilution in a blasthole stoping environment. A series of 3-D numerical models were developed and analyzed to examine the effect of mining depth, stope geometry and stope setting within the orezone extraction sequence. To quantify modelled ore dilution from the three-dimensional simulations, the ore Dilution Density (DD) is a term introduced in this study to denote potential hanging-wall overbreak. It was found that hanging-wall overbreak is not significantly influenced by depth alone, and that stopes with large or small axial ratios are more stable than large rectangular stopes. It was also demonstrated that, in addition to stope dimension, the amount of unplanned dilution differed according to stope type. Five stope types were identified, based on their position within a tabular blasthole mining sequence. The methodology presented in this paper can be adopted to develop mine-specific design tools for the estimation of ore dilution associated with a proposed mine design. This can prove extremely helpful in the process of underground mine planning and optimization.

May 1, 2007

By Shawn Healey, Ray Norcross

"Site IdentificationNew Britannia MineA 50/50 WX Gold Inc. - High River Gold Mines Ltd. Joint VentureTVX Gold Inc. is the OperatorLocationThe New Britannia Mine is located in the town of Snow Lake, Manitoba, which is situated between Flin Flon and Thompson, 420 miles north of Winnipeg.Brief Description of OperationNew Britannia Mine processes 2000 tonnes per day at an average grade of 4.5 g/t. Mill recoveries are currently 91 YO, accounting for forecast of 98,000 ounces for 1998.New Britannia Mine's mill complex incorporates conventional crushing, grinding and carbon-in-pulp technology. The design capacity of the New Britannia Mine mill is 1850 tonnes per day. The mill has processed upwards of 2300 tonnes per day, with no required upgrades.Gold recovery averaged 89.8% for 1997 compared to the planned 87% recovery expected from projected metallurgical test work. Year to date recovery mid December 1998 stands at 91.1 %Cash costs for the 1998 year to date were down to U.S. $221.49 per ounce, down 12% from the 3rd quarter of 1997. Milling costs for 1998 YTD were at Cdn. $9.38 per tonne and Cdn. $73.50 per ounce.Geology - (Orebody Description)The Snow Lake gold deposit is located within the Aphebian Flin Flon / Snow Lake Greenstone belt. This belt is composed of an assemblage of poly-deformed volcanosedimentary supercrustal sequences intruded by pre and sin tectonic ultra mafic and mafic intrusions and sin to post tectonic granitoid.The principal gold bearing rock at the New Britannia Mine is made up of quartzcarbonate material in sequence of basic and acidic volcanic rocks contained within a shear zone. The ore itself is gold associated with the sulphide mineral arsenopyrite and contains some pyrite, pyrotite, plus chalcopyrite. Proven and probable reserves at December 31, 1997 were at 4.04 million tonnes at 4.6 g/t and underground exploration continues to confirm the extension of the ore zones to depth."

Jan 1, 1999

By R. Tyreman, G. Ritson

"The Red Lake Mine is situated in Balmer Township, Red Lake area in northwestern Ontario. It is an underground mine that has been in production since 1948. The property was originally known as the Dickensen Mine and was shut down in 1996.A feasibility study was carried out in 1998 and it was determined that a new mill should be constructed with a throughput rate of 600 stpd. The life-of-mine average gold grade was projected to be 1.35 oz/t with gold predominantly associated with arsenopyrite and pyrite. Metallurgical testwork indicated that the optimal flowsheet for gold recovery would include an autoclave for oxidation with a carbon circuit for adsorption. To limit capital cost and establish cashflow, the mill was constructed without an autoclave. The recovery by gravity and cyanidation was projected to be 83%. A flotation plant was constructed at the tail end of the circuit to recover the additional gold associated with sulphides from the leach circuit tailings. This material is being stockpiled onsite for future oxidation treatment.Detailed engineering was started in early 1999 and the first gold was poured in August 2000. One feature of the project was the use of Contact Lake equipment from Cameco’s Contact Lake project. The entire mill was purchased and equipment re-used where possible. The capital cost for the process facilities was C$3 1.5 million."

Jan 1, 2001

By Brad Sampson

Project Ownership ?Discovery Metals Limited ?ASX (DML), BSX (DML), AIM (DME) ?Market Cap AUD 195M ?Key assets ?Boseto Cu ?Dikoloti Ni The Boseto Copper Project ?Location ?Setting ?History ?Status ?Future

May 1, 2010

By K. Adham, C. Lee

Over the last forty years, a number of specific fluidized bed applications in nickel extraction have been developed for commercial use. Five important processes have gained particular acceptance, namely, sulphide ore roasting, nickel sulphide (matte) roasting, nickel oxide reduction, laterite ore pre-reduction, and nickel chloride pyrohydrolysis. These applications involve different feed materials and process conditions, however, all benefit from fast reaction kinetics and high heat and mass transfer rates in the fluidized bed reactors. They have been studied, tested, and implemented by various nickel producers, who have published their results in many papers and patents. This paper examines the design issues surrounding the application of fluidized bed technology to the above nickel processes. Based on the available data in the open literature, computerized process modelling is used to provide generic flowsheets that illustrate the key features of each process.

Jan 1, 2004

By Steven R. McCutcheon

ABSTRACT - The Bathurst-Newcastle district, a subcircular area approximately 50 km in diameter, contains 37 massive-sulfide Zn-Pb-Cu deposits that have defined tonnages, and has 58 additional significant occurrences. The largest deposit is Brunswick No . 12, with total reserves (including past production) of 148 million tonnes grading about 12.50% combined Pb-Zn. The deposits/ occurrences are spatially associated with a felsic volcanic pile that contains a significant sedimentary component. In the vicinity of the Brunswick deposits the pile is divisible into lower and upper sequences. The lower is characterized by megacrystic rhyolite (QFAS) and coarse- to fine-grained quartz ( ± feldspar) wackes and/or tuffites (QAS); the upper sequence is characterized by aphyric to sparsely porphyritic rhyolites (HWR), micro-breccias, and acid hyaloclastites with interbedded dark gray sedimentary rocks. A greenish gray to dark gray siltstone (GGS) separates the two sequences and hosts the sulfide deposits. Lithogeochemistry of !east altered samples shows that the QFAS and HWR have an igneous character, whereas the QAS and GGS have a sedimentary sig­ nature. The two types can be distinguished on the basis of total alkalies (Na2O + K2O) versus SiO2/Al2O3, and Ti02 versus Fe/(Fe+ Mg). Some trace elements, such as Sr and Y, also help differentiate the two types. The QFAS differs from HWR by having higher La/Yb ratios but lower Zr and Th. The Bathurst deposits do not show a close spatial association with rhyolites but rather are stratiform bodies (lacking clastic textures) within fine-grained sedimentary rocks. The scarcity of barite and other sulfates indicates that there was little mixing between the metal­ bearing fluids and cold seawater. High Fe/(Fe+ Mg) ratios in chlorites also indicate the fluids did not contain a significant seawater component. These features and the large size of many deposits suggest that the deposits formed from metal-rich pore waters that were released catastrophically from an acquifer in the footwall stratigraphy.

Jan 1, 1992

By P. A. Hacquebard, M. P. Avery

"Gondwana coal deposits are widespread and are known to occur in four continents. They are present in Brazil, India, South Africa, and Australia. From coal petrographic examinations and a detailed literature survey, it is interpreted that Gondwana coals are present also in Canada and the United States. Laurasia, or Northern Hemisphere, coals occur in the United States, Canada, and Europe. They form the main coal producing fields of the world. Megascopically, Gondwana coals have a uniform, micro-banded appearance, with a dull lustre; Laurasian coals are bright and have distinct bands of vitrain and clarain. Petrographically, Gondwana coals, compared to Laurasian coals, are lower in vitrinite, but higher in inertinite, particularly in semifusinite. Mineral matter averages 16% in Gondwana coals and 5.7% in Northern Hemisphere coals.Gondwana coals are characterized by thick seams that terminate through lithification (Versteinerung), whereby coal passes laterally into shale. Laurasian coal seams are thinner and terminate by splitting and digitation.Vitrinite/inertinite ratio data indicate deposition of the Gondwana coals in dry marshes under strong oxidizing conditions. The Laurasian coals originated in wet marshes in a reducing environment. As deduced from fossil plants and fossil spores, temperate and near arctic conditions apply for the Gondwana coals. A tropical and subtropical climate is indicated for the Laurasian deposits. The Gondwana coals were formed under allochthonous conditions. They derived from vegetation that drifted into the peat bogs. The Laurasian coals are autochthonous and originated from vegetation that grew and was buried in the peat bogs. The Gondwana coals are Late Carboniferous and Early Permian. The Laurasian coals are entirely Late Carboniferous."

Jan 1, 2004

By Jean-Marie Fecteau

The gold mine sector is presently facing low gold prices as well as technological challenges. Its competitiveness and survival will depend on new mining methods and equipment to improve ore extraction. In 1999, Natural Resources Canada has invested new funds over a period of three years at CANMET?s Experimental Mine to establish the Narrow-Vein Mining Project. A team of engineers and researchers specialised in mining, mechanics and electronics engineering are working to meet the critical need of ore-extraction technology. CANMET?s program in mechanisation and automation for narrow vein mining had, prior to 1999, realised several important achievements, many in co-operation with a consortium of mining companies (Soredem). The investment of new funds in this area will contribute to develop technologies to improve the productivity, as well as health and safety conditions of the narrow vein mining industry. Several important impacts of this project will be monitored. Specifically, a database of methods and equipment used in narrow vein mining is being developed. A key thrust is to identify operators? needs with respect to the development and automation of mining methods and equipment. Based on those needs, research and development projects will be created. The main problems identified following meetings with mine operators are described with a few elements of solution and the Web site created for the broadcast of the results is presented.

Oct 1, 2001

By Mark Aylmore, Guy Deschenes

"Increasing pressure are motivating the gold mining industry to develop a substitute to cyanide for leaching gold. This effort in mainly based on the high toxicity of cyanide and on the lack of efficiency of cyanide in the treatment of mildly refractory gold ores (sulfides and pre-robbing). Consequently, in only a few years, consortia have been created to elucidate and implement a new technology. The most promising lixiviant that has been selected to replace cyanide is thiosulfate. This paper will present a critical analysis on the latest developments in thiosulfate leaching and illustrate the potential and limitations of the technology with experimental data. Finally an assessment of the cost and performance of thiosulfate leaching relative cyanidation will be evaluated.INTRODUCTIONConcerns regarding the toxicity of cyanide and inability of cyanide solution to effectively leach some carbonaceous gold ore or mild refractory gold ores have made the gold mining industry evaluate alternative lixiviants to leach gold. This concern has been heightened recently by the cyanide spill at a mine in Romania, which devastated a 250-mile stretch of the Danube River and its tributaries, and the environmental damage at Ok Tedi mine in Papua New Guinea. Some countries and locations have prohibited the application of cyanidation to recover gold, such as, California and Colorado States, Japan and Turkey etc.There are several potential non-cyanide lixiviants (Sparrow and Woodcock, 1995) for gold extraction, such as thiosulfate, thiourea and halogen. A pilot feasibility test (Marchant and Broughton, 1987) had suggested that thioureation might result in acutely toxic byproducts even after treatment. Scientists of Swedish Academic of Sciences reported that thiourea is a carcinogen. Halogen is also a pollutant to the environment. Thiosulfate leaching appears to have very good potential as an effective and less hazardous procedure for gold and silver extraction from auriferous ores. In addition to being much less toxic and relatively cheap, it forms a stable anionic complex with gold but is less reactive to other metals, for instances, copper and carbonaceous materials, in comparison with cyanide."

Jan 1, 2001

By B. J. Clauzier

"The Falconbridge Limited approach to employing communication equipment is first, to determine what is required in a given situation, second, to evaluate the possible alternatives, third, to select the most suitable hardware and, fourth, to determine what modifications, if any, are required to ensure not only successful implementation but continued low-cost reliability. Two examples are examined.The first situation required remote video monitoring of an acid loadout station. Several alternatives for linking to theremote site were investigated, including hard-wired, slow-scan and microwave. A comparison of these alternatives is shown and an appraisal of the performance of the selected microwave link is presented.The second situation required direct voice contact between the two members of an underground tram crew. Alternative solutions are described and an evaluation of the selected system- SHF portable radios - is presented.ObjectivesIn general, projects must have four main objectives: (1) to improve the safety of its operations; (2) to reduce its operating and capital costs; (3) to increase the efficiency of its work force; and (4) to increase its productivity. ScopeCommunication, when used wisely, can be a good tool to achieve these objectives. Projects can be kept simple using existing technology and adapting it to a particular task. To ensure the success of the project, it was necessary: to determine the project objectives; to evaluate the possible alternatives; to select the most suitable hardware; to adapt the hardware to the application, if required; and not to provide more than is necessary.Application at FalconbridgeTo illustrate this approach, two examples of actual installations at the Sudbury Operations are presented, sulphuric acid loadout, and the Falconbridge Mine haulage system."

Jan 1, 1987

Located in Timmins, Ontario the Porcupine Joint Venture, a pooling of assets between two existing operations (the Dome Operation of Placer Dome (CLA) and the Hoyle Pond Operation of Kinross Gold Corporation) came about on July 1st, 2002; Placer being the manager of the Joint Venture with 51% ownership and Kinross with 49%. The formation of the Joint Venture was the realization of the dream of many who could envision the benefits of the whole area being operated as one entity ? the combination of the majority of assets in the Porcupine Camp into one venture containing tremendous synergistic potential of manpower, infrastructure, land tenure and exploration development. The name Porcupine in the gold mining industry brings with it the legacy of world class gold mines; the Hollinger, McIntyre and Dome with a proud tradition of excellence. The name Porcupine brings with it the legacy of over twenty individual mining companies in operation at any one time, producing over 65 million ounces of gold.

May 1, 2003

By James Scott

Outline Deposit Overview and Brief History ?Geologic Setting ?Local Geology ?Petrography ?Geochemistry ?Mineralization ?Geochronology ?Conclusions Deposit Overview ?Porphyry Cu-Mo-Au ?Discovered 1957 (BIK Syndicate) ?Various programs, most significant: ?Hecla(1970s) ?Teck(Late 1970s Early 1980s) ?Copper Fox Metals (2005 -Ongoing ?optioned from TeckComincoin 2002) ?Measured and Indicated Resources: ?847Mt grading: ?0.292% Cu ?0.019% Mo ?0.202g/t Au ?1.796g/t Ag ?Total ~ 0.485 % Cu Eq.

May 1, 2006