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By R. P. van Hille, A. W. van Zyl

The BIOX® culture, aiding liberation of arsenopyrite/pyrite occluded gold, is inhibited by thiocyanate (SCN > 1 mg/L); precluding the recycling of tailings water up-stream of the bioleaching circuit. The activated sludge tailings effluent remediation (ASTERTM) process is a biological process that was developed to facilitate water recovery and treat waste water on-site (to achieve a SCN concentration < 1 mg/L) to be recycled or disposed of. The aim of this study was to investigate the effects of changing temperature and SCN loading on the SCN degradation ability of the mixed microbial population clue to seasonal temperature changes and fluctuations of SCN concentration in the waste water.

Jan 1, 2011

By Paul Girodo

Government Approval For Foreign Workers 1.Service Canada Work Permit Tasks: i. Prove there are no Canadian Journeymen; ii. Use heavyweight stakeholders; iii. Understand the FWU transformation taking place today. Government Approval For Foreign Workers 2.Provincial Nominee Program (PNP) i. Build relationships; ii. Use heavyweight stakeholders; iii. Continually demonstrate benefits to the Province from foreign Journeymen. Government Approval For Foreign Workers 3.Letter from Union Supporting Temporary Foreign Workers i. Easiest path to approval ?CLAC model

May 1, 2006

By A. R. Farkoosh, J-P. Fortin, M. Pekguleryuz, S. Bagherpour

"Titanium aluminides are structural intermetallics which offer an attractive combination of high temperature strength and light weight. For such properties, these intermetallic alloys have become front-runners in replacing nickel-based superalloys used for several high temperature applications. These alloys are produced from metallic titanium, aluminum and master alloys involving an expensive and difficult process. A low cost alternative to current industrial production method is the new modified aluminothermic process which directly reduces titanium oxide (TiO2) to titanium aluminides. Nevertheless, this process has itself significant challenges in achieving alloys free of oxide inclusions; the close densities of the slag and the titanium aluminides makes slag/molten metal separation a challenging task. Usually, the alloy produced requires a second refining step. In this study, thermodynamic calculations based on CALPHAD method were performed to determine the solidification path and an attempt has been made to develop a criterion to increase the density deference between the slag and the alloy by alloying with appropriate elements. Furthermore, scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques were utilized to examine the microstructure and phase selection of three Ti-Al alloys produced by the aluminothermic reaction, including the as-cast, refined in a controlled atmosphere and inert-gas-refined alloys. The composition range of the alloys studied was restricted to the a2-Ti3Al + ?-TiAl phase field (Ti-30Al) in the binary Ti-Al phase diagram leading to a lamellar structure with different complex intermetallics as shown in Figure 1.INTRODUCTIONTiAl based alloys are promising structural materials for high temperature aerospace and automotive applications. This is due to some attractive properties such as low density, high specific strength, high specific stiffness and high temperature strength retention (Wen-bin, Xue-wen, Hong-fei, & Yong-feng, 2011). These alloys have become leading candidates to replace Ni-based super alloys in gas turbine engines. Replacement of Ni-based super alloy parts with titanium aluminides is expected to reduce the structural weight of high performance gas turbine engines by as much as 20–30% (Kothari, Radhakrishnan, Sudarshan, & Wereley, 2012)."

Jan 1, 2016

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 L. H. Michaud

"Albian Sands Energy (ASE), an oil sands surface mining and extraction operation, is currently undergoing start-up and is scheduled to ramp-up to full production by mid-2003. Startup includes the selection and implementation of over 75 IT systems or computer applications which include: engineering applications; systems required to control mining activities, maintenance, the processing plant and utilities; and also systems required to run the company, such as human resources, finances and inventory/ warehousing.This paper outlines the processes used for the selection, implementation and integration of these systems in order to optimize the use of information and to meet the technical, business and IT requirements of the company. The first step in ASE’s approach to identifying system requirements is the development of a business activity model, outlining all tasks involved in running the operations. The computer applications required to accomplish each task are then identified by having the IT team work closely with each technical and business unit. Historically, at some companies, the selection of systems has been led by the IT team or by consultants, with little input from the technical or business units. Typically, this results in products that do not meet the company’s expectations. To ensure a more positive outcome, ASE believes that it is imperative that the company’s technical and business people be closely involved in the selection process.Integration of the IT systems is also key, including linking all applications through a data warehouse and EDMS. Over 120 required integrations have been identified. This ensures the storage of all data in only one location, data security, and easy data and document retrieval for all requirements throughout the company"

Jan 1, 2003

By David E. Pearson

"There are many tests that can be used to characterize and classify coals, and describe their quality. One of the easier tests, and most versatile in its application, is petrography. Rank and coal type are precisely defined by petrographic evaluation, and in this paper they are compared with other definitions of rank and coal type. Brief descriptions are given of the various rank tests, and of rheological and coking tests used to describe coking-coal quality in Canada. Similarly, tests used to evaluate thermal coal quality are discussed. Finally, the use of these tests as parameters to classify Canadian coals is examined with reference to four coal classifications.Introduction Among all coals there are two independent variables that are required to evaluate coal quality. These are, coal rank and coal type (or composition), and although coal petrography can be used to precisely define them, other methods are often used to provide values that are, in fact, functions of rank and coal type. For example, volatile matter yield is used as a proxy for rank, and free swelling index is used as a proxy for coal type in the International Classification of Hard Coals by type. Currently, there are a number of methods in use in Canada to define rank. The approach taken here, (obviously the author's bias), is that Romax, the mean maximum reflectance of vitrinite, is both a quick and an accurate measure of rank. It is logical to compare the other techniques employed in the measurement of rank to this favoured method. Coal type is, in theory at least, simply a quantitative measure of the various varieties of coal. In practice, the microscopic entities are assigned to a Reactive or Inert category, and at that point objectivity fades from petrography. Despite this somewhat subjective approach, petrographic composition of coals remains an independent variable of such.importance that its place in the evaluation of coal is essential. In this paper, a variety of me.thods that are used to assess rank and coal type are reviewed and compared; the influence of these variables over other parameters that are used to determine the quality of metallurgical and thermal coals is examined, and their usefulness in coal classifications is discussed."

Jan 1, 1985

By M. Jayaraman

With the ever increasing demand for commodities, due to changes in lifestyle and increase in population, people are striving to find ways to keep up. Mining is one essential element in the solution. Though being a powerful boost to a country?s economy, mining can have disastrous effects in the absence of waste management practice and technologies; because of the harmful heavy metals and toxic chemical waste that is generated as a by-product in mining operations. It is an established and documented fact that pollution is a major concern for communities having to live with it. Disproportionate water consumption significantly impacts local rivers and ponds thereby reducing freshwater availability and have given rise to social conflict. In light of these misgivings, management and treatment of mine water and waste has gained considerable attention recently. In this paper, we summarize some of the treatment methods that can be adopted by mining companies to reduce their environmental footprint. Appropriate treatment solutions depend on various factors including available space and capital cost for treatment solutions, type of mining waste generated, current state of the mining plant, geographical location, and other location specific issues. Incorporating waste and water management solutions as a priority within mining operations is critical for addressing increasing regulatory requirements and a starting point for initiating other Corporate Social Responsibility (CSR) programs. Collaboration among mining companies, NGOs, local community, and government facilitates successful projects which build trust leading to long term relationships. In this paper we also talk about the benefits of implementing a CSR project that captures the focus of local communities and allows the mining company to focus on operations. Implementing a sustainable business model that incorporates the broader community impacted by projects will continue to benefit even after the mining company ceases operation in that location. The challenges involved with implementing effective CSR projects, which require measuring and reporting effectiveness to create a positive social, economic, and environmental impact is also presented in this paper.

Aug 1, 2013

By J. Miettunen

"The lining of a grinding mill has an important role in creating the conditions for the grinding process. The main purpose of the lining is to transfer the energy taken by the mill motor to the contents of a mill. The power draw curve of the mill, if measured with sufficiently short intervals, describes how well the lining works in lifting and mixing the material to be ground.The power draw curve can also be used for determining the volumetric filling of a mill. This new measuring technique was developed at the Pyhasalmi concentrator in 1989-90. The measuring device with its PC-connections offers an excellent tool for controlling volumetric mill filling, for maximizing throughput and for research purpose (e.g. process studies, mill linings design).The paper describes the new method and the results achieved at Outokumpu's concentrators.INTRODUCTIONVarious methods have been developed for measuring mill load; weighing, noise, etc. Weighing is one of the most reliable methods but installing the sensor to existing mills is often difficult. Besides the load measurement does not indicate the volumetric filling if the specific gravity of the mill feed fluctuates. Noise measurement has often failed with its sensitivity to various disturbance sources.As known, the power draw measurement is one of the most accurate measurements in grinding circuits and therefore it has been utilized in sophisticated control, e.g. in power peak seeking algorithms for maintaining maximum grinding efficiency.About 10 years ago power oscillation measurement was developed at Pyhasalmi concentrator. In this method the amplitude of the oscillation caused by the lifters was measured. The oscillation amplitude and the mill filling has quite a good correlation and together with the power draw measurement it could be used for maximizing mill throughput (Koivistoinen and Miettunen, 1989). The main difficulties in this method were that the dependence between mill filling and the amplitude is unlinear and that the dependence also is individual for each mill.The method developed during 1989-90 is also based on the power oscillation but on its phase shift. In principle level of the material in a mill is measured. The method has been successfully used for maximizing throughput at Pyhasalmi and Enonkoski concentrators and at Harjavalta slag concentrator."

Jan 1, 1991

By John B. Phillips

The mine is entered by a central vertical shaft, strongly timbered, and containing two compartments-one for the passenger cage, the other for the large skips bringing the ore to the surface. A man-way, for emergencies, is also provided, parallel to the shaft. The cage is a single-deck steel box, carrying about thirty persons; by means of arrangements above and below, it can also hoist and lower materials needed in the workings. Levels are run at intervals of 100 feet. In special cases, where the ore conditions warrant, sub-levels are operated, such as those at 1,113 feet and 1,123 feet (Fig. 7), which are connected by winzes with the 11 th level. One of these was pushed for 40 feet, and then abandoned because it was unprofitable to take up ore of the grade encountered. The ore between levels is removed by stoping. The drifts follow the course of the veins as much as possible, with numerous cross-cuts. Winzes, raises, connections, etc., are blasted out where needed. The main drifts are at least 8 ft. high by about 9 ft. wide. All former narrow drifts had to be widened some time ago, by ruling of the Ontario Department of Mines, to lessen the danger of accidents with cars in the small passages. Accurate plans of the under-ground workings are kept in the office, and extensive surveying is always being done underground to keep the maps up to date, measure the cubical contents of stopes, and so forth. Timber is extensively used in the construction of supports and chutes, and in the sinking of the shaft. Steel and concrete are too ex pensive to compete with timber, which 1s abundant in such sections as have escaped forest tires.

Jan 1, 1926

By K. J. G Hedges

"Once a health based guidance limits for exposure to diesel exhaust have been established, and as part of a multi-disciplinary team, the program for exposure reduction should incorporate the plan-do-check-adjust cycle. Setting a suitably protective (health based) occupational exposure limit (OEL) for diesel particulate matter (DPM) and nitrogen dioxide is a key driver to reduce exposure. It is important to go beyond regulations and reduce exposure to diesel exhaust, DPM, as low as reasonably achievable (ALARA) such as that prescribed under the Australia, Queensland Mining and Quarrying Safety and Health Regulation 2017 where under section 135 Limiting workers exposure, the workers exposure must not exceed the exposure limit applying to the worker for the hazard; and is ALARA. It appears that previously acceptable OELs are no longer safe. Therefore it is important that the internal responsibility system be implemented and the precautionary principle approach be followed, especially as it may be some time before a suitably protective OEL specifically for DPM is in place. One leading multi-national mining company BHP Billiton has acknowledged a significant lag that exists between regulatory action and the level of science that informs health risk. This company is managing exposure to diesel exhaust to as low as technically feasible. This same company that has set an interim target for managing diesel exhaust to 0.03 mg/m3 is achieving these levels which paves the way for other mining companies and general industry including construction. The Occupational Cancer Research Centre 2017 recommends reducing personal exposure to within 0.02 mg/m3 (EC) for underground mining and 0.005 mg/m3 for other workplaces. Controlling DPM is important to prevent cancer however it is also important that that nitrogen dioxide (NO2) be reduced (ALARA) and that careful selection of control technology be considered such as the proper selection of a diesel oxidation catalyst so that the level of NO2 does not in fact increase. The example from BHP Billiton provides a leading practice including using a multi-disciplinary approach and the importance of controlling emission at source and having an auditable diesel emissions based monitoring program in place."

Jan 1, 2019

By D. P. R. Smyth

The limestone reef reservoir at Swan Hills consists essentially of a "buildup" of successively smaller atoll-like layers. Precipitation of calcium carbonate within the lagoonal area of each layer essentially kept pace with growth of the outer organic lattice. Within the reef mass, six de-positional environments characterized by specific suites of fossils (or fossil fragments) and associated limestone textures are recognized as follows: ( 1) Aerated moderately agitated water of normal marine salinity (widespread shelf or submerged reef-built platform). Thamnopora-type corals, Amphipora, "pancake" stroma-toporoids, crinoids, articulate bra-chiopods, rare rugose cup corals, and ostracods occurs in light gray-buff skeletal microgranular limestone of low permeability. (2) Semi-stagnant quiet water of normal marine salinity (leeward side of reef). Crinoids, articulate brachio-pods, rare thamnopora-type corals, Amphipora, pancake and bulbous stromatoporoids, rugose cup corals, ostracods and gastropods occur in impermeable dark brown argillaceous skeletal calcilutite with thin black bituminous shale beds and rare dark chert nodules.

Jan 1, 1961

By Fathi Habashi

"A process is proposed for the treatment of phosphate rock for the recovery of uranium and the lanthanides. The process assures the production of phosphatic fertilizers without polluting the environment with radioactive material.IntroductionWhile many processes for uranium recovery from phosphoric acid produced by the H2S04 route are known and utilised commercially, little is known about uranium recovery from phosphoric acid produced by the HN03 route1. Advantages of the latter route are both the elimination of the gypsum disposal problem, and the possibility of radium disposal in a controlled way2. Further, the lanthanides originally present in the rock can be recovered if the nitric acid route is used; they will be mostly lost in the gypsum produced by the sulphuric acid route3. In the present work a scheme for the recovery of uranium and the lanthanides from phosphate rock without interfering with the normal route for fertiliser production is proposed using HN03 as a leaching agent. Attention was also given to uranium decay products and their separation so that they might not contaminate the fertiliser4. Further, an attempt was made to defluorinate the leach solution in order to upgrade the fertiliser and at the same time recover the fluorine5. Rapid analytical methods for the determination of uranium, radium, and lanthanides in phosphate rock were developed6,7."

Jan 1, 1997

By Rob Morrison, Peter Cameron

"Many products and technologies have been developed from outcomes of research projects carried out by the Julius Kruttschnitt Mineral Research Centre (JKMRC). When these products and technologies are applied to the design and optimisation of blasting, comminution and separation, improvements in profitability can be realised.In 1970 Alban Lynch promoted two practical ideas to improve plant operations:• Ore and equipment properties can be separated allowing experience with one type of ore or equipment to be transferred to other types of ore and equipment. If this experience was encapsulated in a mathematical model, then these properties could be combined and used to simulate (ie. to design and to optimise) complete mineral processing circuits.• Many problems associated with scale-up from laboratory to industrial equipment could be eliminated by experimental work on full-scale equipment in the plant.Many JKMRC research projects have focussed on the development of models of unit operations in mineral processing and their application to process simulation.Models of comminution and classification developed at the JKMRC have been used since the early 1980's. Ore characterisation techniques developed to support these models are licensed world wide through JKTech. The application of comminution modelling techniques to blasting, which optimises the process feed size distribution is used in Mine-to-Mill® projects. The advances in the understanding and modelling of froth flotation over recent years have provided the opportunity for integrated ore characterisation and process optimisation from resource to product.JKMRC project outcomes often provide proven opportunities for the mineral industry to improve performance and productivity. JKTech was established in 1986 to commercialise and market the most promising outcomes and thus ensure their continuing availability to the mineral industry.They include:• Commercial software (JKSimMet, JKSimBlast and JKMetAccount).• Monographs (Comminution and Blasting).• Technologies (Mine-to-Mill® and flotation optimisation).• Hardware products (JKFrothCam, JKJetLift® and the Mineral Liberation Analyser).This paper summarises these technologies and their benefits."

Jan 1, 2003

By S. S. Teal, W. W. Weber

"AS THE TITLE implies, this paper will deal with the unusual rather than the standard practices as employed . at the property of North Rankin Nickel Mines, Limited. Fortunately •the mining, with the exception of permafrost conditions, and the milling practices, are the normal approaches dictated by the size, type, and character of the orebody. The unusual aspects are linked directly or indirectly to the isolated location and are •principally ancillary requirements or services covering a broad range from climate to supplies and from finance to entertainment. It is our intent to cover the more salient points of interest together with a brief description of the general operation.To understand the primary motivation of the mine, it must be made clear that North Rankin was conceived as a foothold in the Canadian North, that region embracing 40 per cent of the Dominion which ex-tends north of the commercial tree-line and which includes nearly 50 per cent of the Precambrian Shield, our mainstay of Canadian mining. Secondly, this project was born in an atmosphere of premium sales in the nickel markets, assuring a rapid pay-back of the heavy •capital expenditures. And finally, it has •been coddled through the stark reality of a competitive metal market with the hope and trust that the experiences and achievements will lead over the bill to a bigger and better mine in this virgin territory. This is the briefest story of the mine's history, but it pays tribute to the many people who, in thirty years since .discovery, have championed this project."

Jan 1, 1959

By H. A. Khorami, T. Wong, B. Velapatino, E. Asselin, T. Donnelly, E. Bryce, R. Dixon

A copper–nickel concentration gradient alloy was designed and fabricated through a powder metallurgy (PM) process. Copper and nickel powders were mixed with different weight ratios from 0 to 100% copper in 10% increments. Each powder mixture was poured inside a cylindrical die and compacted between two punches using a hydraulic press machine at pressures up to 70 MPa, resulting in approximately 1 mm thick layers (discs) of pressed Cu–Ni powder. These 11 Cu–Ni compacted powder layers, i.e. 0–100% Cu with 10% increments, were then compressed together with pressures up to 420 MPa to form a green part. The green part was sintered in a vacuum furnace at 1000°C for 10 hours to form a solid mass (PM part) of Cu–Ni concentration gradient alloy. In the sintering process, Cu and Ni particles fused together and formed a single piece due to diffusion of the atoms across the boundaries of the particles. The diffusion of atoms also converted the stepwise concentration change into a uniform concentration gradient. INTRODUCTION Copper has numerous applications in different industrial sectors due to its superior physical, electrical, mechanical and chemical properties such as its excellent thermal and electrical conductivity, resistance to fatigue, high ductility, and resistance to corrosion. Moreover, copper and its alloys have natural antimicrobial properties. This has opened up new applications for copper–based self–disinfecting surfaces in healthcare in an effort to mitigate healthcare–associated infections (HAIs). HAIs affect millions of patients each year, leading to significant morbidity and mortality as well as financial losses to healthcare systems (World Health Organization, 2016). HAIs spread through three main routes: (a) iatrogenic in which HAIs are a direct consequence of medical encounters and/or treatment; (b) person to person where organisms are transferred between healthcare workers, patients, and visitors; and (c) environmental where transmission occurs via contaminated surfaces and equipment (e.g. doorknobs, railings, toilets/commodes, medical carts). The use of antimicrobial copper–based materials on high touch surfaces could diminish pathogen transmission via this latter rout. This has subsequently led to the development of a variety of copper–based materials for use in healthcare settings and promoted the investigation of the antimicrobial efficacy of copper–based materials.

Jan 1, 2019

By P. Taskinen, D. Lindberg, H. Viitala

The formation of copper chlorides in flue dust or deposits in heat recovery boiler of copper smelters or waste-fired boilers may lead to formation of corrosive partially molten deposits on walls and heat exchangers of the boilers. These deposits can contain various other metals, such as alkalis, Fe, Zn, Pb together with oxides and sulfates. In the present study, a thermodynamic model for copper-containing binary and ternary metal chloride systems within multicomponent CuCl-CuCl2-FeCl2-FeCl3- PbCl2-ZnCl2 system has been assessed and optimized based on own experimental phase equilibrium data, as well as literature data. The thermodynamic properties of the liquid phase was modelled using the quasichemical quadruplet model and a thermodynamic database was optimized to predict all available experimental data within the experimental error limits. The thermodynamic database allows for more accurate predictions of potential corrosion-related issues in various heat recovery boilers and waste-fired boilers due to formation of copper chlorides. INTRODUCTION In the copper flash smelting, flue dust can cause severe problems in the gas train, used for separating dust from the SO2-rich off gas, by forming corroding accretions on the walls of the heat recovery boiler. Formation of dust build-ups in the boiler need to be cleaned regularly and potential corrosion damage checked, requiring costly and unscheduled shutdowns of the flash smelting process. Compounds of copper and zinc among other elements having high vapour pressures may volatilize during the smelting of the copper concentrate, forming dust when the process gas cools down. Also, particles of solid or liquid iron oxides originating from the ore get transported with process gas to the heat recovery boiler as a result of entrainment in the flue gas (Miettinen, 2008) The dust deposit build-ups on the boiler walls are formed partly by direct impact of particles and partly by vapour condensation on the boiler walls. The initial deposition takes place by the condensation of vapours that contain zinc, lead, arsenic and other metals having high vapour pressures. Also, low melting point eutectic components of alkali salts such as chlorides and sulphates can act as sticky cohesive particles attaching to the boiler walls. The fine particles landing on the surface of the porous dust deposit layer react in the SO2-rich atmosphere of the boiler to sulphates. The process gas within the boiler contains SO2, O2, SO3, H2O and N2 that diffuse into the porous accretions to form a stagnant gas layer within the dust deposit structure. The composition of this gas layer may differ greatly from the composition of the process gas that is flowing on the surface of the accretion layer. Locally HCl and H2SO4 are formed and even a reducing atmosphere may exist within the dust deposit layer, allowing new reactions to take place. The local micro-atmosphere may enable metal sulphates to be reduced to secondary sulphides and even metallic components. Within the accretion layer, components may be formed that would not be stable in the gas atmosphere inside the boiler (Miettinen, 2008). This may be the mechanism by which for instance chlorides of Cu, Fe and Zn are formed within the deposit layer.

Jan 1, 2019

By A. R. Barnes, N. O. Lotter

Recoverable economic copper sulphide minerals such as chalcopyrite, bornite, chalcocite and covellite often occur together in varying proportions in the major copper-bearing ores, and have individual flotation requirements and characteristics. Pyrite also occurs in these ores to varying extents as the sulphide gangue, and is problematic because of its natural tendency to float quickly and easily. In a bulk sulphide float, selectivity against pyrite is desirable, particularly if it does not host other paymetals such as gold or silver. At the same time it is a requirement to float all of the copper sulphides despite their electrochemical differences. The electrochemistry and semiconductor properties of these minerals are reviewed, together with implications for flotation with and without collector addition. Mixed collector systems for the improved flotation of these sulphides are proposed as a solution. The use of xanthate and dithiophosphate in the collector suite allows the co-existence of dixanthogen and free dithiophosphate radical because the latter has a higher redox potential requirement than xanthate to oxidise to the dithiolate. Because some of these minerals require dixanthogen, and others, free thiolate, to generate surface hydrophobicity, a bulk flotation of all the species becomes possible in the overlapping area of Eh and pH between the two dithiolate equilibrium lines on the Pourbaix diagram. The arsenic-signature copper minerals are added to the study, since many copper operations encounter arsenic as a penalty element in the saleable concentrate. It is shown that the addition of arsenic to the copper and iron sulphides alters the semiconductor and electrochemistry properties, and in turn, its flotation characteristics. The degree of mineral association and liberation between these minerals can be a complicating factor due to textural associations, and should also be considered in the process as a next step.

Jan 1, 2016

By Wang Xianzheng

For a long period of time, the Chinese Government has been attaching great importance to and supporting the rapid development of the coal industry. Particularly since more than 30 years ago, when China introduced the Reform and Opening-up policy, the reform and development of the Chinese coal industry has witnessed world-recognized achievements. National coal production increased from 618 million tonnes in 1978 to 3.52 billion tonnes in 2011. While China?s coal production accounts for 49.5% of the world?s total, its annual production growth contributes to over 80% of global production growth. China is a country utilizing coal as its main source of energy. As the Chinese Government gives support to the rapid development of new and renewable energy sources, as well as to increased coal utilization efficiency, the ratio of coal in the primary energy consumption mix will gradually decline. However, for a long period of time to come, the total volume of coal demand will keep rising modestly. The Chinese Government has been highly committed to and actively promoting the overall, coordinated and sustainable development model, which puts people first. It has put forward a strategic task to build an ecological civilization, and highlighted its resolve to uphold the basic national policy of resource conservation and environmental protection, with a view to the pursuit of sustainable development. China will incorporate its response to climate change into the national economic and social development program, and take effective measures to lower CO2 emissions 40?45% per unit of GDP in 2020 compared to 2005. At the same time, China will increase the ratio of non-fossil fuels to 15% in the primary energy consumption mix. All of the above factors have raised requirements for the Chinese coal industry, with implications for clear directions, plans and goals for the development of the coal industry.

Aug 1, 2013

Project Details ? Located 420 km northeast of Yellowknife, Northwest Territories ? Jericho kimberlite discovered in 1995 ? Feasibility study showed +3,000,000 carats recovered from 2.6 million tonne reserve ? Nine year mine life ? Approx. 100 person workforce in full production ? First mine for Tahera, First new mine for Nunavut Completed Ambitious Construction Schedule During 2005 o Feb ? Mar/05 Winter road mobilization o Mar ? Dec/05 Pre-stripping, earthworks o Mar ? Apr/05 Camp facility, occupied May 3 o May ? Dec/05 Process plant o Jun ? Dec/05 Maint. shop, fuel storage, power plant o Jan ? Mar/06 Commissioning, start-up o April 2006* COMMERCIAL PRODUCTION

May 1, 2006

By V. A. Ettel

Current practices in electrolytic winning and refining of copper , nickel and zinc are reviewed from the point of view of their respective energy requirements. The electrical energy requirements of these processes are broken down in to the individual components, which belong to two basic categories: (a) thermodynamic energy requirements (G of the desired reaction) : (b) energy losses (anode and cathode polarizations, ohmic drops in the electrolyte and in the cell hardware, energy losses due to unwanted side reactions and electrical shorts). The individual energy components are separately examined for each electrolytic process and the potential for energy saving in these processes is discussed. It is shown that many potential energy-saving measures are uneconomical at the present time, as they increase over-all operating costs. The discussion is focused on those approaches which hold most promise for the future.

Jan 1, 1977