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By J. Drozdiak

In this paper we present the results of preliminary investigations into the applicability of new laboratory scale tests for the prediction of operating gap and specific throughput in high pressure grinding rolls (HPGR). The work is a part of the CAMIRO HPGR research program being conducted at the University of British Columbia, which aims to develop a suite of small-scale tests and procedures for the selection and sizing of HPGRs. A focus of the presented study is to test sample types in terms of their terra-mechanics based characteristics and relate them to specific throughput and gap results from pilot HPGR testing on the same samples.

Jan 1, 2012

By D. Milne

Laser profilometers exist for obtaining very accurate two and three dimensional profiles of joint surfaces. The application of this technology is not commonly applied to the collection of field data on discontinuity surface roughness. Rugged and portable field devices are not commonly used and the value of the possible field data that can be collected has not been well recognised. This paper reviews commonly used field techniques for assessing discontinuity roughness, discusses the value of this data and presents a new laser profilometer design for field application.

May 1, 2009

By Jean-François Dorion

La corrosivité des environnements miniers souterrains est un phénomène peu étudié au Canada. En plus de détériorer les systèmes de soutènement, la corrosion s?attaque aussi à divers installations et équipements souterrains. Cette étude, débutée en janvier 2007, est l?établissement d?une banque de données afin de caractériser les environnements miniers souterrains selon leur potentiel de corrosivité pour les systèmes de support de terrains. Pour ce faire, cinq (5) mines ont été sélectionnées afin de comparer les environnements : Laronde, Géant-Dormant, Niobec, Mouska et Doyon. À chacune des mines, trois (3) endroits ont été étudiés. Les résultats préliminaires démontrent une grande variabilité des conditions d?une mine à l?autre ainsi qu?à l?intérieur même d?une mine. La minéralogie des roches et du gisement influence la composition des eaux souterraines et la présence des sulfures joue un rôle important sur l?agressivité de l?eau et de l?air des mines de l?étude. Afin de déterminer le potentiel de corrosivité, plusieurs paramètres doivent être considérés et la mine doit être zonée selon l?agressivité des endroits.

Feb 1, 2008

By Balakrishnan Nanthakumar, Marek Pawlik, Dennis Grimm

"The anionic flotation of a high-iron phosphate ore from Agrium - Kapuskasing Phosphate Operations was investigated through batch flotation tests in the presence of soda ash. The flotation data were supplemented by titration of the flotation pulp with soda ash, analysis of process water chemistry, and determination of the mineralogical composition of the ore. The results of lab tests were applied to the flotation circuit design allowing the flotation plant to efficiently process problematic ores. Process control measures (pH, conductivity) were also developed.Calcium cations and sulfate anions were identified as the dominant ions present in the process water when the difficult-to-process ores are beneficiated in the flotation plant. The concentrations of calcium and sulfate ions were consistent with the presence of a small amount of a calcium sulfate mineral in the ore although an oxidation/weathering process of iron sulfide minerals present in the ore could also be responsible for the observed water chemistry and subsequent flotation problems with the ores. The latter possibility suggests that the long-term stockpiling of such ores may have a highly negative impact on the flotation process.The role of soda ash in the flotation circuit is to precipitate metal cations from the pulp thus allowing the tall oil-based collector to selectively interact with the phosphate components.INTRODUCTIONPhosphorus minerals are the main source of this element for the production of fertilizers, and the froth flotation process is the most important technology for beneficiating phosphate ores. The flotation concentrate from Agrium-Kapuskasing Phosphate Operations (KPO) is transported to Redwater Fertilizer Operations in Alberta (also operated by Agrium) where the phosphate concentrate is converted into a phosphate fertilizer and other important chemical products. The KPO phosphate ores differ widely in mineralogy and phosphate grades, and are broadly divided on-site into three classes. The easy-to-float A-type ores do not pose any major flotation problems, but the B-type and “marginal” ores, which are quite common in the KPO igneous phosphate deposit, are not always readily-floatable using the current reagent suites and process parameters (pulp density, feed particle size, pH). In fact, marginal ores are presently considered impossible to process by flotation. A-type ores contain normally more than 15% P2O5 and less than 8% ferric oxide equivalent (Fe2O3). B-type ores are approximately of the same P2O5 grades as A-type ores but their iron content may reach 30% Fe2O3. Any material containing less than 15% P2O5 is rejected as waste rock."

Jan 1, 2008

By D. R. Boyle

"Abstract - The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite > arsenopyrite > galena > Bi-Sb sulfosalts > chalcopyrite > tetrahedrite group > sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was trans- ported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By László Guczi1

Nanosize model gold particles with varying size were fabricated by deposition of a 10 nm thick gold film onto SiO2/Si(100) substrate by electron beam evaporation followed by modification using low energy Ar+ ion bombardment. The change in particle size were monitored by the Au 5d valence band states determined by ultraviolet photoelectron spectroscopy (UPS). The gold/iron oxide interface was studied by iron oxide deposition on gold. It was found that the energy profile of Au 5d valence band states are strongly redistributed with decreasing the gold particle size mostly affecting at the lowest and at the highest binding energies. The size effect in the UPS spectra can be interpreted by the energy redistribution rather, than by narrowing the 5d states. The iron oxide deposition increases the catalytic activity in CO oxidation whether it is on gold nanoparticles or on a continuous 80 nm thick gold film. The activity enhancement is significantly larger in case of gold nanoparticles. The interface interaction is operative in enlargement of the catalytic activity even if gold particles are not exposed to the surface, but they are located below the iron oxide layer.

Oct 1, 2003

By N. I. Basuki, E. T. C. Spooner

"Abstract - More than 2800 published fluid inclusion data (primary inclusions) from eighteen typical Mississippi Valley-type (MVT) Zn-Pb deposits and districts were examined to study possible relationships between MVT fluid properties and metal tonnages and ore grades. The mean Th and salinity values for fifteen MVT deposits and districts are 122°C ± 21°C and 20.7 ± 2.6 wt% CaCl2 equivalent, respectively. In general, temperatures increase from pre-ore to ore stages, and salinities decrease from ore to post-ore stages. From post-ore to late calcite stages, salinity and temperature decrease with various trends within specific districts.Several conclusions are drawn: first, results show that Hanor’s (1996) salinity threshold for metalrich basinal fluids applies to typical MVT ore fluids (~16 wt% CaCl2 equivalent). Second, the lower limit of mean Th values of measured MVT deposits and districts (n = 15) of ~75°C is similar to Hanor’s (1996) observed temperature threshold for metal-rich basinal brines of ~60°C (n = 224). Third, there is no statistically significant relationship between fluid inclusion homogenization temperatures (Th) and metal tonnages or ore grades. Fourth, there seems to be a tendency for large tonnage districts/deposits to be associated with mean fluid salinities that are relatively low (~16 to 21 wt% CaCl2 equivalent) within the overall range of salinity means (~16 to 26 wt% CaCl2 equivalent). There is also a correlation between higher ore grades and higher salinities. Finally, comparison with other sedimentary rock-hosted Zn-Pb deposit types shows a trend of salinity decrease and temperature increase from MVT, sandstone-hosted and diapir-related Pb-Zn deposits, to vein-type and Irishtype Pb-Zn deposits, and then to sedex deposits. However, more data are needed for sedex deposits. The salinity threshold for significant Zn-Pb transport decreases to =~10 wt% CaCl2 equivalent at ~250°C. This study suggests that fluid inclusion analysis during exploration may be useful in assessing ore-forming potential (threshold salinity) and possible ore grades (salinity)."

Jan 1, 2002

By V. G. Papangelakis, G. A. Moldoveanu

The use of anhydrite (AH) seed, control of acidity levels and ageing were assessed as means to promote the conversion of freshly produced metastable gypsum generated in-situ to the less soluble anhydrite phase and force deposition of calcium sulphate on seed as opposed to on equipment as scale, while achieving lower terminal aqueous calcium concentration as well. It was found that moderate sulphuric acid levels (0.25M) and ageing in the presence of AH seed accelerated the gypsum-AH conversion, achieving 100% transformation of the metastable gypsum generated in situ to the more stable, less soluble AH in 6-7 days, while lower/nil acidity did not promote more than 30% AH conversion for 10 days, even in the presence of AH seed. These findings indicate that anhydrite seeding, ageing and incomplete neutralization are beneficial for scale control as well as achieving lower calcium levels, thus rendering the resulting solution more amenable for recycling.

Jan 1, 2015

By B. R. Maas

Processing material at a consistent rate through the continuous countercurrent decantation (CCD) thickeners presented a major bottle neck to unlocking additional value from one of the post-flotation streams at the Kansanshi processing plant. The manual operation of the thickeners making up the CCD train resulted in frequent imbalances and process upsets across units. The automation of CCD trains is notoriously tricky as the available manipulated variables are outnumbered by the parameters requiring regulation. The implementation of an advanced, auction-based, control philosophy to manage the movement of both slurry and solution inventory through the train addressed this parameter imbalance and lead to the stabilisation of the circuit. Since the commissioning of this control strategy: an additional 7 200 dmt/day (+36% throughput) of material can reliably be processed through the train, the number of monthly downtime events has reduced, and a saving of $354 000/month in reagent cost has been achieved. INTRODUCTION CCD operation Agitated leaching is a common method used in hydrometallurgy to extract a metal from its host ore. The host ore is initially finely ground to liberate the surfaces of the valued minerals and improve the kinetics of the leaching process. The ore is then contacted in an agitated tank with a lixiviant to dissolve the desired metal into the aqueous phase. The resultant slurry from the leaching process comprises of a solution pregnant in the metal salt and a barren ore. The first purification step taken after leaching is to wash the pregnant liquor solution (PLS) from the depleted ore. On the industrial scale, a set of between two to ten thickeners arranged in a countercurrent configuration is often used to carry out this separation (Perry & Chilton, 1973). The slurry is introduced at the head of the train and a wash solution at the tail. The two streams are pumped through each thickener countercurrent to one other. At each stage the residual PLS in the slurry is mixed and diluted down with the countercurrent overflow solution from the downstream thickener. The diluted slurry is fed into the thickener where the solids separate out through gravity sedimentation. The settled solids are channelled towards the underflow of the thickener by a rake mechanism and pumped downstream to the next thickener in the train. The outcome is the recovery of a PLS from the overflow of the lead thickener and a slurry of washed solids from the underflow of the tails thickener.

Jan 1, 2019

By Richard J. Haslinger, C. Mark Rebagliati, James L. Oliver

Abstract - Exploration at the Specogna gold deposit has identified a geological resource of 65.0 Mt grading 1.63 g/t Au, which equates to 3 million ounces of contained gold. This resource is hosted in a low-sulfidation epithermal deposit of Miocene age that is localized along the northwesterlytrending Sandspit fault. The fault has juxtaposed Late Cretaceous mudstone of the Haida Formation to the west, with Late Tertiary coarse clastic sediments and lesser andesitic volcanic rocks of the Skonun Formation to the east. A plagioclase porphyritic dacite dike intrudes the Haida mudstone and Skonun sediments along the fault. Gold mineralization, in hydrothermal breccias, veins and stockworks developed mainly in Skonun sediments and dacite. These are formed in an 800 m long zone that roughly parallels the Sandspit fault. The gold zone is funnel-shaped in cross-section, approximately 300 m wide at surface, 220 m above sea level, and narrows to approximately 50 m, at sea level. The deposit lies within an elongate zone of moderate to intense hydrothermal alteration that, at surface, extends over a known area of approximately 2 km2. Its western extent is bounded by the Sandspit fault. There is an asymmetric alteration zonation, with a core of silicic-potassic (adularia) and smectite-illite clay alteration that is bounded to the east by argillic alteration. Similar zoning defined by the distribution of metals reflects the position of the main feeder conduit. Mineralization of altered wallrock is dominated by 1% to 4% auriferous pyrite and marcasite. Gold and silver occur as electrum; individual silver minerals have not been identified. Other sulfides are rare, and are identified only microscopically. The mineral suite is typical of low-sulfidation epithermal systems. Gold occurs in early, multi-phase, variably bladed and banded quartz veins and breccias, which are cut by barren, single phase, drusy quartz veins.

Jan 1, 1998

By Lang Tao, Jun Wang, Wei Xiao, Wenqing Qin, Pan Cao, Guanzhou Qiu, Key Lab of Biohydrometallurgy of Ministry of Education, Central South University

"The effect of metal cations on the rutile flotation using styryl phosphoric acid (SPA) as the collector was investigated by micro-flotation test, bench scale flotation test, zeta-potential measurements and adsorption measurements. The micro-flotation results indicated that Fe (?) and Al (?) ions in low concentrations had obvious activation on the rutile flotation, and Pb (?) ions in low concentrations had smaller activation of rutile, but Fe (?), Al (?), Pb (?), Ca (?) and Mg (?) have strong inhibition of rutile flotation in high concentrations. The bench scale flotation results indicated ethylene diamine tetraacetic acid (EDTA), boracic acid, and sodium hexametaphospate can decrease the metal ions concentrations, and increase the recovery of rutile flotation. Adsorption measurements and zeta-potential measurements revealed that Fe (?), Al (?) and Pb (?) ions were adsorbed on the rutile surface, and had interaction with SPA. But when these ions concentration were over the largest adsorption capacity, residual metal ions could occur chemical reaction with SPA.INTRODUCTIONRutile is one of the favored minerals for production of titanium dioxide white pigment, primarily through the chloride manufacturing process (Stanaway 1994; Hou et al., 2013) However, the majority of rutile ores belong to refractory ores, while flotation is one of the most efficient methods to separate fine rutile from gangue (Dolbear et al., 1937). With the flotation development, many effective collectors were successfully applied in the oxide ore. Many reviews have indicated that organic phosphonic acid collectors showed good selectivity on oxide ores such as ilmenite and rutile (Bulatovic & Wyslouzil 1999; Liu & Peng 1999).It is inevitable that many types of metal cations are present in ore pulp. These metal cations significantly influence the flotation of minerals. Liu et al. (2015) showed that Ca2+ and Mg2+ could improve the floatability of spodumene at pH 12.5 and 10.0, respectively. The authors proposed that Ca2+ and Mg2+ ions readily form hydroxy complexes (CaOH(l) and MgOH(l)) and precipitates as (Ca(OH)2 and Mg(OH)2) in strongly alkaline solutions. Fan and Rowson (2000) investigated the effect of Pb(NO3)2 addition as an activator on ilmenite flotation and showed that it could improve ilmenite floatability. The addition of Pb(NO3)2 resulted in an increase of ilmenite zeta potential in both weakly alkaline and acidic aqueous solutions. Mehdilo, Irannajad, and Rezai (2015) studied three kinds of ilmenite of different origins and discovered that both Mg and V had a negative correlation with ilmenite flotation, while the Mn content seemed to correlate positively with flotation efficiency. A number of studies have also showed that Fe3+ can improve the floatability of ilmenite (Fan et al., 2009; Nuri, Mehdilo, & Irannajad, 2014)."

Jan 1, 2016

By Philippe Caudal

This paper presents a case study in which a slope failure was observed on the west wall of the LAB Chrysotile mine in the vicinity of the main ramp in January 2010. Airborne LiDAR results were used to evaluate slope geometry before and after the failure occurred. Back analysis of the failure was performed to assess rock mass properties at the slope scale using various numerical techniques: limit equilibrium, finite elements and fracture networks. The various approaches correlated well with field observations.

Aug 1, 2013

By Philippe V. Scheers

Polycrystalline gold, glassy carbon and gold-activated glassy carbon electrodes were compared for the production of hydrogen peroxide by the cathodic reduction of dissolved oxygen. Gold was deposited on glassy carbon by sputtering with a sputter coater and by electrodeposition from a diluted KAuCl4 solution using short potential steps. The sputtered gold particles were not adherent enough, but there were no adhesion problems with the electrodeposited gold particles. The gold coverage of the glassy carbon surface could be varied by applying a different number of potential steps. The overpotential for the electroreduction of oxygen to hydrogen peroxide decreases with increasing gold coverage of the glassy carbon surface, and for gold coverages exceeding about 16 %, the overpotential is close to that observed on polycrystalline gold.

Oct 1, 2003

By M. B. Kime, E. K. Kanowa

"Heap leaching of low-grade copper-cobalt oxidized ore and solvent extraction of copper, cobalt, manganese, and zinc were investigated. Heap-leaching parameters were optimized using agitated and tray batch leaching tests, capped by tests on a pilot semicontinuous heap-leach plant. The optimum pregnant leach solution yielded 2,350 mg/L Cu, 3,800 mg/L Co, 3,600 mg/L Fe, 130 mg/L Mn, 25 mg/L Zn, and 0.58 g/L solids in suspension, with pH and acidity of 1.27 and 3.66 g/L, respectively. Copper, cobalt, and impurities (Mn and Zn) were extracted using (v/v) 30% CP-150, 20% IONQUEST® 290, and 20% D2EHPA, respectively; overall recoveries of copper, cobalt, and impurities were 98, 99, and 70%, respectively.RÉSUMÉ La lixiviation en tas des minerais oxydés de cuivre et de cobalt et l’extraction par solvant du cuivre, du cobalt, du manganèse et du zinc ont été étudiés. Les paramètres de lixiviation en tas ont été optimisés à l’aide d’essais de lixiviation en discontinu sur un plateau, complétés par des essais relatifs à une usine pilote de lixiviation en tas en semi-continu. La liqueur-mère optimale a produit 2 350 mg/L de Cu, 3 800 mg/L de Co, 3 600 mg/L de Fe, 130 mg/L de Mn, 25 mg/L de Zn et 0,58 g/L de solides en suspension, avec un pH et une acidité respectifs de 1,27 et 3,66 g/L. Le cuivre, le cobalt et les impuretés (Mn et Zn) ont été extraits avec un pourcentage volumique (v/v) de 30 % de CP-150, de 20 % d’IONQUEST ® 290 et de 20 % de D2EHPA, respectivement. Les récupérations totales de cuivre, de cobalt et d’impuretés étaient de 98 %, 99 % et 70 % respectivement.INTRODUCTIONBoss Mining S.P.R.L. is a privately owned hydrometallurgical plant located in southeastern Democratic Republic of Congo. It treats oxidized ores of copper and cobalt that are recovered by sulphuric acid heap leaching (Trujillo, Cisternas, Gálvez, & Mellado, 2014; Kime, Kanowa, Mulaba- Bafubiandi, & Diyambi, 2016) and solvent extraction processes (Crane, Urbani, Dudley, Horner, & Virnig, 2009; Fisher, 2011; Kime et al., 2016). The ore to the plant is primarily sourced from the Luita and Mukondo mines. Geological prospecting work by Gecamines and Boss Mining showed that the Mukondo mine contains a very large cobalt reserve not yet exploited, but with grades as low as 0.2%.Currently, Boss Mining is focusing on the production of copper, but is investigating methods to efficiently produce both copper and cobalt. A challenge in the production of cobalt from this ore is its presence in the third oxidation state. This requires the addition of reducing agents, which increases the overall operating cost (Kime & Makgoale, 2016). Cobalt solvent extraction is also very sensitive to impurities such as nickel, zinc, manganese, and aluminum, which are often co-extracted (Swartz, Donegan, & Amos, 2009). This sensitivity to impurities requires the optimization of operational parameters to lower impurity levels as much as possible in the electrolyte."

Jan 1, 2017

"In mining operations, it is widely accepted that strategies to drive operational goals must revolve around improving plant availability, reliability and process efficiency. In this paper, an integrated solution framework for reducing process variability, increasing process efficiencies and maximizing plant availability and reliability is discussed within the context of a typical milling circuit. The framework exploits a real-time analysis “gap” evident in production operations that prevents timeous identification of equipment and process failures. This is achieved by leveraging predictive analytics for equipment health monitoring, control loop monitoring and advanced regulatory control solutions towards enhanced process performance, improved asset management and regulatory compliance. The framework provides for early and actionable warnings on equipment and process degradation using real-time operational data.INTRODUCTION The changing landscape of gold mining and processing presents many challenges that threaten sustainability of existing (marginal) operations as well as deter investment in new projects. As existing “shallow” ore resources become depleted, mining operations are increasingly treating low-grade ores with complex and randomly variable mineralogical characteristics. For example, in South Africa, historically one of the major gold producers, the average grade of ore treated has been decreasing from averages above 4.5 – 5 g/t to current grades averaging less than 3 g/t within a decade (Chamber of Mines, 2012). Moreover, lower tonnages are being treated as a result of the narrowing of the available resource base. Also, the regulatory framework has tightened over the years due to heightened concerns on the safety, health and environmental impacts of mining and related activities."

Jan 1, 2014

By L. A. M. Castro

As Canadian mines progress to greater depths, magnitudes of induced stresses increase, becoming high enough to cause rock mass damage and failure during excavation. In addition, depending on the orientation of key geological structures in relation to the in-situ stresses, induced shear loading can be developed on these structures, creating the potential for: a) remobilization of existing geological structures, b) formation of new seismically active structural zones, created through rock mass damage and coalescence along such structural zones, and/or c) interaction between existing and newly created structures. Numerical analyses were carried out to investigate four possible factors that might cause fault slip on controlling structures, namely: (a) unclamping, (b) day-lighting, (c) stress rotation and (d) pillar shear. Application to an underground mine in the Sudbury Basin allowed verification of these factors and the proposal of two alternative mine planning methods to limit fault slip on key structures: (1) pillar clamping and (2) stope sequencing.

May 1, 2009

By Z. Zhang, D. Bouchard, H. Blanchette, A. Lemieux

This paper describes quality control methodologies for the production of semisolid A356 aluminum slugs with the SEED process. A methodology based on destructive tests carried out with an apparatus measuring the force to slice the slugs is presented. The force measurements were correlated with the solid phase morphologies of the slugs and were validated against a non destructive methodology that consisted in monitoring the temperature evolution of crucibles to produce the slugs and the drained metal. Results from the destructive and non destructive methodologies are compared and discussed.

Jan 1, 2006

By G. M. Ritcey, A. W. Ashbrook

"This paper summarizes the optimum leach conditions for each Of several cobalt-containing arsenical feed materials, describes the solution treatment prior to purification of cobalt recovery, and discusses the plant operation on one feed as well as the treatment of effluents.IntroductionDuring the period 1962-1964, when the demand for uranium was low, Eldorado Mining and Refining Limited (Eldorado Nuclear Limited) made a decision to undertake a three-year diversification program. One area chosen in this program was that concerned with the processing of cobalt-nickel materials. Many such materials were evaluated over the three-year period, ranging from tailings, residues, ores, concentrates and speiss to metal scrap. Cobalt feed materials, on which much of the effort was concentrated, were those containing arsenic together with other metals such as silver, copper, nickel and iron. This paper describes the treatment of arsenic-bearing feed materials (ranging from 0.3 to 570/0 As) and the subsequent purification stages required before the separation and recovery of high-purity cobalt. Because of the current interest in treating cobalt ores, it seemed appropriate that the information on the treatment of various cobalt feeds should now be made available . Although a large amount of data were generated during the research and process development program, a complete scientific correlation and understanding could not be achieved. Nevertheless, the data may provide a guide to others involved in processing not only cobalt, but other arsenical ores."

Jan 1, 1981

By M. B. McClenaghan, O. P. Lavin, Ian Nichol

"Exploration in most areas of Canada has to contend with problems posed by glacial overburden. In many areas exploration for gold has been based on the sampling of tills, frequently by deep overburden drilling, and analyses of heavy mineral concentrates. Notwithstanding the significant role that till geochemistry has played in the discovery of some important gold deposits over the last few years, increased appreciation of the nature of the glacial history and stratigraphy and the character of gold within till has led to the recognition of a number of ways whereby the effectiveness of exploration can be improved upon.In order for till geochemistry to be useful in exploration, a number of conditions must be fulfilled, including:1. mineralization, or alteration halo related to mineralization, subcropping at the bedrock/overburden interface;2. glacial erosion and dispersal of a recognizable signature of mineralization into the glacial sediments;3. preservation of glacial sediments containing this geochemical component (trace metal or mineral) at positions subsequently selected for sampling (normally drill sites);4. correct identification of specific till units and associated ice movement history;5. collection of adequately large and representative samples;6. appropriate sample preparation and processing;7. appropriate geochemical analyses; and8. correct data processing and interpretation.While we have no control over the first two geological conditions, and only limited control over till availability, we can control the quality and thoroughness of sampling, sample identification, sample preparation, analysis and interpretation. In particular attention needs to be focussed on obtaining a large enough sample to be adequately representative, an unbiased sample must be collected, together with appropriate sample processing, analysis, data processing and interpretation. It is considered that by modifying or extending existing approaches to gold exploration the chances of exploration success can be increased. In particular, analyses of both the heavy mineral and minus 63 µ m fractions of till is recommended because gold in till may occur in different size fractions."

Jan 1, 1992

By F. F. Roberto, E. Kirby, A. R. Marchbank

The application of biologically assisted methods for metal extraction in the mining industry has a long history, but development of modern techniques has been relatively slow. There is, however, a resurgence of interest in the industry with the recent development of methods to successfully treat base metals concentrates. Two major pilot plant programs for treatment of chalcopyrite concentrates have been initiated in the past year and results from one are beginning to be released. This paper provides an overview of methods that have been applied in the past, from the earliest deliberate applications of the technology, through the copper and uranium heap and dump leach applications, the more highly engineered agitated tank leach gold applications and the developments currently taking place in the industry.

Jan 1, 2003