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By D. J. Hains

IN this paper we shall examine the Why, Where and How concerning the agglomeration of iron ores and concentrates. Fig. l answers the questions @f why there is so much interest at the present time in the art of agglomeration. The use of sinter or pellets in the blast furnace has materially increased their rated •capacity. ':'President Hains Company Ltd. Engineering J. S. McMahon ( 1) reports an increase from 653 tons of .pig iron per day to 1140 tons of pig iron per day with the use of a 100 per cent sinter burden on one of his blast furnaces. In the United States the use of 100 per cent pellets has increased pig iron production from approximately 1800 tons per day to over 3000 tons pig iron per day (2). In our economic system the general objective is to produce more and better commodities cheaper. Fig. 2 shows the decrease in coke consumption with increased tonnages from the furnaces when using -

Jan 1, 1961

By Fathi Habashi, Michel Pagé, Farouk T. Awadalla

"Chrysotile asbestos can be dyed with certain dyestuffs to form stable coloured products whose hemolytic and cytotoxicity are greatly reduced. Examples of these dyes are Thiazol Yellow G (a monazo dye) and Trypan Blue (a diazo dye). Other dye stuffs, for example, basic dyes with triphenyl methane structure, Brilliant Yellow (a diazo dye), and Methylene Blue (a thiazine dye) colour asbestos but do not reduce its toxicity. Similarly alizarin, 8-hydroxyquinoline, and representative members of the phthalein group Bromocresol Purple and Phenolphthalein.IntroductionThere is, at present, a controversy regarding the dangers of asbestos fibres, and attempts are being made to render it less toxic. One of these attempts consisted of treating chrysotile asbestos with gaseous phosphorus oxychloride, POCI], at ambient temperature and in absence of moisture. The product had to be heated at 300°C to 500°C to expel exess entrained reagent to get a material containing 0.5070 to 5% phosphate groups and known as Chrysophosphate (Lalancette and Dunnigan, 1982). This product showed decreased toxicity as measured by its hemolytic effect on red blood cells (fable 1). In another approach, Flowers (1983) showed that when chrysotile asbestos was thoroughly mixed with a solution of ferric ammonium sulphate and the slurry was then filtered and dried, the product showed a marked decrease in cytotoxicity.In the present investigation the problem of toxicity was considered from a different point-of-view. Chrysotile asbestos is a hydrated magnesium silicate that can be represented by the structural model shown in Figure 1 from which it can be seen that magnesium hydroxide groups, Mg(OH)2, form a part of the silicate structure. Certain organic reagents that are known to react with magnesium ion in solution to form chelates were reacted with asbestos to find out whether a chelate was also formed on the fibres, and if so , what will be the hemolytic action and cytotoxicity of the product."

Jan 1, 1991

By M. S. Badollet, N. W. Edgerton

"A study of the physical properties of long grades of asbestos fibers imported into the United States during the past eight years has disclosed information that will contribute materially to effective selection and use of fibers for electrical products. The study embraced fiber lengths, volume resistivity under three different conditions, total iron by chemical analysis, magnetic rating, conductivity of an aqueous ex-tract and its sodium chloride equivalent.The fibers examined included chrysotiles from Rhodesia, British Columbia, and Barberton area; marlime from Bechuanaland and Province of Quebec; amosite and crocidolites from Africa and Australia; and anthophyllites from Mozambique and from Georgia in the United States. Volume resistivity values provide a relative basis for estimating the electrical performance of end products; magnetic rating -an estimate of the quantity of iron compounds present in excess of those in the asbestos structure; conductivity of an aqueous extract; and an estimate of the ionizable impurities in fibers.Tests of these factors yield in-formation, not heretofore generally known, which may serve as a guide in the evaluation of asbestos fibers for electrical products."

Jan 1, 1960

By Claudia Gasparrini

"Factors affecting the extraction of gold are of a mineralogical nature. Knowledge of the mineralogy of the ore or metallurgical product to be treated, if appropriately combined with the metallurgical test work, may improve gold recoveries. .This paper outlines the mineralogical techniques f or the study of gold ores and metallurgical products and describes the gold mineralogy in relation to its metallurgy. An effective plan for studying refractory and other difficult ores, combining metallurgical test work, chemical analysis and mineralogy and capable of giving positive results over relatively short periods of time, is suggested.IntroductionFactors affecting gold recoveries are of a mineralogical nature and include (i) the gold-bearing minerals, (ii) their grain size and, particularly where the grain size is very fine (10 microns in diameter and less), (iii) their host minerals and (iv) the association these form with the gold-bearing minerals.Mineralogical studies of gold ores and metallurgical products containing gold in economic amounts (today down to 1/10 of one ounce per tonne or 2.84 ppm) are difficult and time consuming. Mostly because of such reason, metallurgical testing (test work) is usually done simply by trial and error without understanding the causes for failure or success.Mineralogical studies, if appropriately conducted and combined with the test work, provide an efficient mean s of improving recoveries through the understanding of gold losses derived from the use of the wrong technique for separation. The information they provide is therefore the first step in the development of recovery techniques, for those ores where the test work alone failed to produce positive results."

Jan 1, 1983

By Nav Dhadli

Tailings from Oil Sands MiningWhat are they? Challenges Solutions Regulatory Environment Definition of the AFD Tailings Treatment Process 2010 AFD Pilot/Demonstration ProgramTechnical challenges Performance and Results Next steps Oil Sands Industry Collaboration on Tailings Technology TAILINGS ?WHAT ARE THEY? Mixture of remaining water and solids following bitumen extraction process Composed of water, sand, silt, clay, small amounts of hydrocarbon (bitumen, solvent, and asphaltenes) A necessary part of production in excavation of oil sands and removal of bitumen

May 1, 2011

By K. D. Eng, W. T. Tierney

"During the past century, the development of vehicular transportation has benefitted tremendously from the performance improvement in engines in a situation where low-cost, plentiful fuel supplies were the order of the day. Engine advances were enhanced by and also dictated fuel modification to better adapt the energy source to the power plant.In discussing the several aspects of the change in approach from ""an engine and its fuel to a fuel and its engine"", the authors touch on the following areas:1. Description of an engine concept that provides the needed flexibility in fuel appetite at good efficiency to cope with future requirement s.2. The constraints placed on liquid fuel resource energy utilization efficiency by special engine-required fuel properties and the fuel efficiency of the various engine types available.3. Future vehicle engine fuel sources. This review will put into perspective the problem associated with the net energy available from future fuel sources under extensive research and development at present.4. A brief review of test data to show that fuel-tolerant and fuel-efficient engines are viable and that, in a fuel-resource-limited future, they can be a ""light at the end of the tunnel.""The Texaco Controlled Combustion System (TCCS)The TCCS is a unique means for stratified charge operation of an internal combustion engine in such a manner as to eliminate the requirement for octane or cetane number specification for the fuel. Octane rating is an empirical engine test method that evaluates a gasoline's resistance to spontaneous ignition or ""knock."" Cetane is based on a different engine test, which determines a diesel fuel's ease of spontaneous ignition . High cetane number enhances cold starting and permits high-speed diesel engine operation. As one would expect, the fuels in current use cover a band when the two values, octane and cetane, are plotted against each other."

Jan 1, 1982

By J. W. Bawden, J. Nantel

"The mine operator has two prime objectives when he operates a mine: (l) the mine must be safe, and (2) the mine must operate with the lowest possible costs. The operator constantly faces a dilemma; if he is over cautious with regard to safety, his costs may be very high, and if he is over-zealous in trying to reduce costs, the safety of his operation may be jeopardized.Modern bulk mining methods rely heavily on high productivity non-entry stoping techniques (e.g. open stoping, VCR, etc.). Such techniques have the advantage of removing the operator from the active and sometimes dangerous mining face and ofminimizing costly development. On the other hand, this generally results in a certain loss of flexibility in following irregular ore-waste contacts. If stopes are opened too large and/or are inadequately supported, severe dilution with resulting escalating costs usually results. If initial access drift support is inadequate for latter mine induced stresses high rehabilitation costs may also be incurred.Optimization of stope dimensions should logically occur as part of a general mine rock engineering program, within the over-all mine planning context. The same program should help highlight those areas where drift rehabilitation may be a problem.Whenever successful mining is performed, rock engineering is being applied, either by design or by chance. The cost implications of planned practical rock engineering as an integral part of mine planning and design can be very significant to the ultimate mining ""bottom line"". At Noranda Minerals Inc. allowable stope dimensions are derived using a combination of numerical stress analysis and empirical design techniques. This paper discusses the use of the above techniques and their limitations as tools for rock mechanics based stope dimension optimization. The potential cost implications of such design efforts within the general mine planning context are also addressed."

Jan 1, 1989

By Brandt Porter, Lawrence K. Nordell, Alexander Potapor

"Improving comminution efficiencies with better machine geometries and motions, improved nip angles, rock movement control, and voids regulation among rocks are some of the next steps to better machine performance. Recent gains (~30%) using high pressure grinding rolls (HPGRS) and vertical roller mills, in theory and practice, are based on Prof. Klaus Schönert’s academic studies (1979–1996) on rock breakage physics. More recently, University of British Columbia Prof. Bern Klein’s studies (2006–present) via the Ph.D. thesis of Z. Davaanyam (2015) further validate theory with practice from laboratory measurements used in this paper.They demonstrated ideal rock compression breakage, within HPGR and vertical roller mill machines using a piston-die apparatus. Similar rock size range is used. The piston-die confine rock breakage behavior. However, these studies do not extend to larger rocks (> 75 mm), and do not demonstrate the influence of rock voids among bifurcation of rocks during comminution. Further, machines fed with larger rock sizes, such as gyratory, jaw, and cone crushers, are not designed or evaluated for geometry nip angle efficiency.Herein we illustrate a performance gain of a new comminution machine, the conjugate anvil-hammer mill (CAHM), first presented at SAG 2011 (Nordell, 2012). The CAHM machine digests rock sizes 400% larger than HPGR, improves rock grip/nip geometry, better improves rock voids, improves surface wear life > 500%, and improves rock containment and slippage during compression. In all, the CAHM machine shows 22 potential improvements over the HPGR. Most importantly, CAHM shows a 50% kWh/ton improvement compared to the HPGR. Our studies use an advanced Discrete Element Method (DEM) computer program called ROCKY. ROCKY simulates moving boundaries, surface wear mechanics, and incorporates rock breakage physics based on the fundamentals of JKMRC T10 protocol [×] with tuned A × b breakage parameters.We calibrate rock breakage in our DEM code to mimicking both UBC laboratory piston-die and HPGR comminution measurements. We then model CAHM with these known ore and machine properties. Differences are illustrated using DEM techniques on each machine, including key points of when each: use geometry; initiate bifurcation breakage; provide a map of particle size distribution by location; illustrate the importance of controlling voids to minimize agglomeration after breakage; machine performance limits; and kWh/ton benefit."

Jan 1, 2016

By H. Bouzahzah

The field of quantitative mineralogy has evolved significantly through the development of image analysis techniques and information technology. Quantitative mineralogical characterization can now be routinely conducted for determining ore compositions and understanding the behaviour of minerals within mineral separation processes. The characterization of mine tailings is another important application of quantitative mineralogy. The estimation of acid and neutralization potential as well as the interpretation of kinetic leaching test results are often based on quantitative mineralogical knowledge (mineral abundance, texture, metal distribution amongst minerals, etc.). The objective of this paper is to determine and compare the accuracy of four mineralogical characterization techniques that are often used for environmental sample analysis: (1) X-ray diffraction, (2) normal analysis from chemistry analyses, (3) normal analysis from specific gravity measurements and (4) SEM-EDS image analysis. For this purpose, three artificial samples were assembled by mixing pure minerals in proportions often observed in mineral processing plant tailings. BILMAT, a statistical data reconciliation software, was applied to reconcile the chemical analyses with the results of other mineralogical analysis techniques and to estimate the acid and neutralization potential of actual mine tailings samples. The acid mine drainage was qualified from the acid potential and neutralization potential equilibrium as determined through quantitative mineralogical analysis. The statistically reconciled data made it possible to predict the metal deportment as a function of their bearing minerals and therefore, in the case of neutral contaminated drainage, to assess metal leaching potential.

Jan 1, 2016

By M. H. Fathi

The aim of this work was to prepare the metallic coatings on 316L stainless steel dental implant and evaluate the corrosion characteristics and thus the biocompatibility of the uncoated and metallic coated dental implants and comparison of the effect of the type of coatings on biocompatibility. Three types of metallic coatings including Tantalum, Niobium, and Titanium coatings were made using physical vapor deposition process on 316L stainless steel dental implant. Structural characterization techniques including; X-ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray Analysis were utilized to investigate the microstructure and morphology of the coatings. Electrochemical potentiodynamic tests were performed in two types of physiological solutions at 37±1 °C in order to determine and compare the corrosion characteristics. All three types of metallic coatings had a positive effect on improvement of the corrosion behavior so that the coatings could increase the corrosion resistance of 316L stainless steel and this trend was independent to the type of physiological environment. Biocompatible metallic coatings could decrease the corrosion current density that is a distinct advantage for prevention of ion release. This can improve the biocompatibility of the implant and, consequently prevention of tissue damages, inflammation and irritation and obtained desirable histopathological response.

Jan 1, 2007

By G. Swan

"The selection of material comprising a backfill is, of economic necessity, site dependent. Nevertheless, given the existing range of typical components-coarse waste, alluvial sand, tailings a balanced or optimal choice is no straightforward matter. A new design approach toward deciding what constitutes an optimum combination of backfill material promises to be useful. In particular a 'binder ' number, based on the mean distance between aggregate particles, specific surface and cement content, is proposed. Using this number, related empirically to compressive strength, the expected mechanical performance of any cemented fill can be predicted.IntroductionOver the years a considerable volume of information has accumulated on mine backfill material design. The principal aggregate component has been deslimed mill tailings, though more recently admixtures of rock waste, sand and tailings are quite common. For these materials uniaxial compressive strength and percolation rate properties are known to be controlled by, among other things, aggregate grading. While empirical formulae exist for relating grading to percolation rates, considerable uncertainty exists concerning strength development."

Jan 1, 1985

By Pizhi Zhao, Jingwei Zhao, Zhenshan Liu, Yiheng Cao

"A new Al-Mg-Si-Zn alloy designed for automotive outer panel was trial-produced with industrial procedure. The final product shows a strong planar anisotropy. X ray diffraction analysis shows such strong anisotropy is caused by the dominating cube texture component in the final product. The reason for such high cube texture component was investigated by tracing texture evolution starting from the hot roll slab. It is found that certain cube texture components already exists in the hot rolled slab. The density of cube texture component shows as a wavy change through the following1st cold rolling, inter-annealing, 2ndcold rolling and solution treatment. This study shows that the cold rolling in the laboratory can well represent the texture evolution during the industrial production. The results obtained by lab rolling hints that change of second cold rolling reduction has weak effect on the planar anisotropy, when the gauge of hot rolled slab and final sheet are fixed.INTRODUCTIONWith the rapid progress of light-weighting in the automotive industry, aluminum sheets get more and more application as closure panel and structure parts. Recently the dominating alloy for outer panel is 6xxx series, containing the main alloy elements Mg and Si. The popular gradesareAA6016,AA6111, AA6022, and AA6014. These alloys still cannot satisfy the various requirements from automotive manufacturers. Most suppliers of automotive aluminum sheets are developing their own specific grades according to the customer’s demand. To increase the baking response, anew Al-Mg-Si-Zn alloy was designed, concerning the high combination energy between Zn solutes and vacancies formed during the quenching stage of automotive sheet manufacture. This combination is helpful to the precipitation of ß”phase during the paint baking (Wang, 2015,2016; Yan, 2014).The plastic strain ratio (r value)is a key index of the formability of automotive body sheet. A high r value means a good formability. The r values in different directions can be used to evaluate the planar anisotropy of the metal sheets. The trial produced Al-Mg-Si-Zn sheet shows a strong planar anisotropy with respect to r values. Since the r value is tightly related with texture, the texture evolution from hot roll slab (HRS) to final T4P temper was analyzed with X ray diffraction (XRD) to find the reason for the high anisotropy. Besides, the cold rolling reduction (CRR) was varied in the laboratory to modify the texture distribution, i.e., the planar anisotropy."

Jan 1, 2018

By H. E. Pawson

Giant Yellowknife is located 600 air miles north of Edmonton on the north shore of Great Slave Lake in the Northwest Territories. In its 24 years of operation some 7,730,000 tons of ore have been treated to yield $175,000,000 worth of gold.The gold ore occurs at irregular intervals throughout a fold-like sericite schist zone cutting Precambrian rocks. The ore is characterized by 40 to 80% quartz - carbonate and about 10% pyrite and arsenopyrite. Considerable amounts of stibnite and antimony sulpho-salts are also present. Gold is finely divided in the native state existing in complex association with the sulphides. In most instances stibnite is barren but minor values are evident on occasion. Visible native Fold, quite prevalent in the early operating years, is, practically non-existent today. It was readily apparent from mineral dressing investigations conducted in .1944 that Giant ore would be difficult to treat. By 1948 a flow sheet had been established and operations began. In the ensuing years, changing ore characteristics necessitated modifications to some process steps and complete abandonment of others. By 1962 the major metallurgical problems were solved and all that remained was the refining of operating performance to its highest level.With one or two exceptions today's operation follows the practice established by 1962 (Fig. 1 - Flowsheet).

Jan 1, 1973

By G. F. Raymond, W. P. Armstrong

"At the time of this study, the Valley mine was producing 23 000 tonnes of ore per day from a large, low-grade porphyry copper orebody. Sulphide mineralization, principally bornite and chalcopyrite, occurs in a stock work of quartz veins in one phase of the Guichon Creek batholith. The property was explored from 1967 to 1982, and was placed in production in 1983.Using a three-parameter lognormal approximation developed by G.F. Raymond at Similkam een and Mount Isa Mines, a geo- statistical conditional probability ore reserve was estimated prior to mining. Comparisons with blasthole kriging and milled ore for the first 17 months of production showed close agreements at all cut-offs between conditional probability estimates and mineable ore. This was not true of either kriging or polygon estimates. An important part of this work was identifying and correcting for bias in both exploration and blasthole samples.IntroductionCominco's Valley lake deposit is a large, low-grade, porphyry copper orebody in the Highland Valley of British Columbia. Total indicated plus inferred ore reserves are 700 M tonnes at ore grade of 0.47070 Cu. At the time of writing, ore milling is at a rate of 23 000 tI d through the old Bethlehem mill. Mining is in 10m horizontal benches using 9.8 m3 shovels and 90 tonne trucks. Since this paper was written, Valley and nearby Lomex have been combined into Highland Valley Copper with a combined oreproduction of about 120 000 tI d.Copper mineralization, principally bornite and chalcopyrite, is regularly distributed throughout the deposit as disseminated low-grade within a granodiorite host rock, and as higher grade veinlets within a stock work of near-vertical quartz veins generally 10 cm or less in width. It is likely that problems with sample variability and sample bias are mainly related to mineralization within quartz veining. Valley geology has been described in detail by Allen and Richardson and by Osatenko and Jones (2). The exploration sampling program and identification of diamond-drill sample bias have been discussed by Armstrong and Newman'»."

Jan 1, 1988

By S. Tavani, T. Rees

The current mining operations at Newmont Boddington Gold Mine (NBG) commenced in 2008, and commissioning of the processing plant started in the latter half of 2009. Metso Process Technology and Innovation were engaged to assist NBG with commissioning and project ramp-up through the implementation of a comprehensive “Mine-to-Mill” Process Integration and Optimisation project. This methodology entailed extensive data collection which included drill and blast audits, ore characterisation, comprehensive comminution circuit surveys and review of operational data to assess the limitations within the current mining and processing operations. The results of these investigations have been used to define the operating base line of both the mining and processing areas and identify improvement opportunities. The use of modelling and simulations, utilising actual production data, has allowed for multiple scenarios to be evaluated, minimising the requirement for actual trials and thereby minimising impact on the operation. Improvements implemented to date include: the introduction of routine rock strength measurement for inclusion in block models, modifications to blast design improving ROM fragmentation and downstream comminution process performance, and changes to improve performance of secondary crushing and grinding circuits. Close cooperation between the mine and plant personnel is playing a significant role in overcoming the challenges presented to this operation and further improvements are targeted for the second full year of process plant operation.

Jan 1, 2012

By P. J. Lunder, R. C. Pakalnis

This paper presents the results of research that has been undertaken in order to develop an improved method of determining the strength of hard-rock mine pillars. Pillars are found in various shapes and sizes in all underground mining operations. Prudent engineering design requires that if pillars are to perform as desired, both the pillar strength and the pillar stress must be determined. A detailed pillar stability study has been combined with an extensive database of published pillar case histories (178)resulting in a new “hybrid” pillar strength formula, “The Confinement Formula”, that utilizes classic strength of rock methods combined with empirical methods. “The Confinement Formula” utilizes a “mine pillar friction term” calculated from the average minor/major stress ratio with-in the pillar core. Statistically, the new formula provides better results at predicting pillar strength for the combined database than the best empirically ft pillar methods that currently exist. “The Confinement Formula” allows for the determination of the strength of mine pillars with an increased level of confidence over previously applied methods.

Jan 1, 1997

By A. Aaltonen, S. Paloranta, H. Myllykangas

A property based dynamic model of flotation was built and validated for training purposes. The model is based on the work of the AMIRA P9 project. The recovery of each particle with composition and size is calculated in a given simulation step. The model takes into account machine and operational parameters such as air flowrate and froth height. The model was created using fullscale test data on Pyhlisalmi Cu-Zn-pyrite ore with flotation kinetics of multiphase particles determined. Simulation and validation shows that model can predict the dynamic behavior of the process accurately enough for training purposes.

Jan 1, 2009

By M. Kunst

The creep behavior of three AJ62 alloys was investigated in a wide range of stresses and temperatures. Multi-level tensile creep tests revealed a distinct primary creep stage and a high stress exponent up to a value of 10. The threshold stress concept which is commonly used in combination with high stress exponents was utilized in the analysis of creep behaviour. This resulted in an effective stress exponent for the AJ alloys indi¬cating dislocation climb as the dominating creep mechanism. In addition, microstructural observations of the lamellar eutectic and of the a-Mg-matrix were carried out using opti¬cal microscopy, SEM and TEM. The creep properties of the alloys are discussed in the context of microstructural parameters such as phase volume-fraction, stability and solute supersaturation.

Jan 1, 2006

By D. C. Carter

"The Nova Scotia Department of Mines and Energy located a drillhole at Riverside Corner, Hants County, Nova Scotia, to examine the stratigraphy, structure and potash potential of the Kennetcook River gravity low. This evaporite-related gravity anomaly is one of the largest virtually unexplored gravity anomalies in Nova Scotia. The drillhole intersected a structurally complex sequence o flower Windsor Group ('B' Subzone) evaporites. Downhole geophysical wireline logs were used, in conjunction with detailed lithological descriptions, to interpret the structure and stratigraphy of the sequence. Similar application of total gamma ray, density, caliper and neutron-neutron log responses allows stratigraphic correlation of Windsor Group carbonate marker units separated by up to 35 km in Cape Breton. This work confirms the value of downhole geophysical logs as a tool in the exploration of evaporite deposits regardless of the presence or absence of high quality core. INTRODUCTIONThe exploration methodology for evaporite (specifically salt/potash) deposits in eastern Canada (and worldwide) is relatively simple: identify a negative gravity anomaly within a favourable geological setting, Windsor/Cordroy Group sediments in eastern Canada, and drill it (Anderle, 1980). Although this is an obvious oversimplification of the necessary expertise in the planning and complet ion of an exploration program, those familiar with potash exploration drilling can attest to the risks and expense, in terms of time and problems , associated with the location and drilling of diamond-drill wildcat holes. Potash exploration programs in eastern Canada, their results and inherent difficulties, have been documented by Anderle et al. (1979), Cooper (1981), Dekker (1982), Carter and Boehner (1986), Carter (1988) and Carter and Anderle (in prep .).Downhole geophysical wireline logs have become an important tool in the stratigraphic and structural interpretation of evaporite sequences in eastern Canada and, in many cases, represent the only information recovered or the only information available due to the drilling method (rotary) and/or the long term instability of evaporite cores. This paper documents examples of downhole geophysical log responses which, combined with detailed lithological examination of drill core, or in the absence of core, are used in the interpretation of the complex lithology and structure of a deformed evaporite deposit. Geological and geophysical data from the Nova Scotia Department of Mines and Energy (NSDME) Riverside Corner 85-1 drillhole are presented here as a partial case history and prime example of the use of this method to interpret the complex structure of an evaporite deposit. Drilling of NSDME Riverside Comer 85-1 was conducted in late 1985and early 1986by the Department (Carter and Boehner, 1986) under a program to assess the potash potential of selected areas of the province as part of the Canada-Nova Scotia Mineral Development Agreement 1985-89. A reinterpretation of a portion of the available data from two exploration drilling projects on Cape Breton Island in the Canso-Bras d'Or area is also presented (see inset, Fig. I). Several drillholes have intersected the Windsor Group evaporite sequence in these areas and the available geophysical logs are a valuable tool in the interpretation of the structure of the deposits. However, no attempt has been made to present or discuss the detailed geological investigation and comparison of these two deposits. They are presented here as an example of the reinterpretation of existing data and their application to stratigraphic correlation and structural interpretation of complex evaporite deposits. Further work is necessary to document the stratigraphic and structural correlation of these two areas."

Jan 1, 1989

By P. T. O'Kane

The PLATSOL® process, initially developed for the treatment of the NorthMet Cu/Ni/PGM concentrate, has seen over the recent years its applicability extended to include numerous other Cu/Ni concentrates of the same type, as well as other precious metals-containing feedstocks. However, several concentrates were found refractory to the typical PLATSOL® conditions, more particularly so the platinum. Attempts to extend those conditions, such as higher temperatures (250°C), longer retention time, increased oxidation conditions, higher chloride additions, were not successful. Detailed mineralogical investigation of those PLATSOL® leach residues indicated the main refractory mineral to be cooperite (PtS). Further metallurgical investigations showed that a thermal pre-treatment of the concentrate effectively unlocked the refractory platinum minerals for the subsequent leach. Temperatures between 400 and 750°C were tested, with the optimum being found around 650°C. The kinetics of the pre-treatment process were fast, and one hour at temperature proved sufficient. Under those conditions, PLATSOL® extractions were re-established around 95% for both platinum and palladium. From a mineralogical examination of the calcine, it was shown that the effect of the pre-treatment was to transform the cooperite and other refractory sulphides into metallic platinum and alloys, amenable to the PLATSOL®. The implications of the pre¬treatment step for the processing of PGM concentrates arc briefly discussed.

Jan 1, 2004