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By Julie Dénommé

Today few in business would argue with the idea that we are living in a world that is Volatile, Uncertain, Complex, and Ambiguous. Coined VUCA by the US Army War College, these four words define the ?turbulence? and ?continuous white water? that the business literature has been documenting for the last decade. This VUCA world became even more relevant to business in 2007 when the Institute for the Future fellow Bob Johansen published the idea of transforming VUCA into Vision, Understanding, Clarity, and Agility. We call this VUCA Prime (VUCA'), and place an infinity loop (8) between them to show their dynamic interaction. This paper presents an exploration of the impact of VUCA 8 VUCA' on business and the conditions under which these dynamic forces help to successfully navigate change.

Oct 1, 2010

"WELCOME/BIENVENUE TO THE COM 2014 IN BEAUTIFUL VANCOUVER!On behalf of the organizing committee, I would like to extend my thanks to you for participating in this year’s Conference of Metallurgists. Recent times have been extremely difficult for the resource sector, but it is crucial for our industry to maintain personal connections through good and bad times. These interactions include technical exchanges, and this is at the heart of MetSoc’s service to its members. The theme of this 53rd Conference of Metallurgists is Prosperity Through Process Advancements. There are thirteen symposia at this year’s conference mainly focused on processing from extractive fields, to materials and the environment. Supporting these topics are the plenary, poster session, and trade show plus opportunities for socializing at functions like the opening reception and the awards banquet.Many people have contributed to this conference, from the authors and presenters to the organizers and the generous sponsors. They are all gratefully acknowledged for their quality work over the last two years. A particular thank you to our student volunteers whom we hope will take advantage of their time at COM to network and to learn about this exciting industry.Again, thank you for being a part of this exciting conference of metallurgists. I hope it will be a memorable experience and that you are able to take advantage of all the conference and Vancouver have to offer."

Jan 1, 2014

By D. J. Scarpato

"Slope construction in shale can present some interesting challenges for geotechnical design engineers and contractors alike. There are challenges that can be expected and designed-for; however, all too frequently, such challenges manifest themselves as “surprises” in the field. Common constructability challenges can include those such as drill hole deviation during drilling for controlled blasting; and, excavation slope instability arising from inconsistent perimeter control drilling. Drill hole deviation results from the cumulative effects from both drilling mechanics and rock mass conditions. Once a hole has initiated the deviation trajectory, it is difficult to rectify drill steel position. Although such challenges are not necessarily unique to shale, they are often exacerbated by weak, weathered and transversely isotropic nature of bedrock conditions. All too often, the working assumption is that shale is “soft” and easily excavatable; however, this blanket assumption can prove to be costly. This paper is intended to provide design professionals and contractors with the practical considerations needed to avoid the “surprises” associated with drill hole deviation, and minimize the potential for costly claims.INTRODUCTIONFor all the slopes that have been excavated worldwide, and for such advancements in excavation technology and field characterization, one might be tempted to believe that the industry almost has slope development down to a science. This is frequently not the case, especially for weak/weathered and anisotropic bedrock. Excavation contractors are still pushed to the limits of what their technology can achieve, and engineers are all too often called to the field during construction, to make potentially risky onthe- fly decisions relative to excavatability, short and long-term slope stability, and project safety. Although there have been a host of other research papers and journal articles that have been written on the subject of deviation over the past 30 years (Brown, Geen, Sinha, 1981), the problems associated with drill hole deviation are still all too frequent. This fact is especially true for civil engineering surface excavations in bedrock."

Jan 1, 2015

By W. J. Tough

THIS paper offers examples of some of the typical calculations which occur in the ventilation of metal mines. The fi.rst section of the paper discusses the problems associated with natural-draft pressure; the second section presents the more common of the calculations concerned with the operation of mine fans; the third section illustrates the integration of the individual problems covered by the preceding sections into the larger problem of determining the operating characteristics of a fan for a particular mine duty. There is a very definite limit to the extent to which pure arithmetic can be successfully applied to the solution of min<; ventilation problems. As mines advance from the exploration, development, and initial production stage to the rime when underground workings become exceedingly complex, there is a considerable increase in the relative importance o theory and judgment in the solution of ventilation problems. These calculations illustrate the application of mathematics to ventilation, but they also in-elude examples of instances where arithmetic cannot be conveniently applied, and important estimates, based on judgment compounded of experience and a knowledge of the theoretical consideration involved, must be made. The inclusion of such estimates is intended as a guide and a warning to the reader; a guide in assisting him to recognize and estimate his own incalculables; and a warning that the solutions must not be blindly applied to his apparently similar problems. These sample calculations are intended to assist the reader in applying the theory contained in the standard texts on metal-mine ventilation. They have been selected from the ventilation experience of a British Columbia mine.

Jan 1, 1942

By J. Chlopas, D. J. Barratt, M. V. Sharp

"This paper describes the modifications made to the Fox Mine copper concentrate bin in order to obtain a continuous flow condition. The design of these modifications is based on test results obtained on Fox Mine concentrate using the flow factor testing machine in the research facilities of Cominco at Trail, B.C.The original design consisted of a cylindrical steel bin on a concrete slab with two slot-discharge openings. Based on predictions of the maximum mass flow hopper angle for conical and wedge shaped hoppers for the concentrate on various potential bin lining materials, Ultra-High Molecular Weight (UHMW) Polymer was selected as a liner.Using the recommended angles for conical and wedge shaped hoppers, the profile of the bin base was changed to suit the existing slot openings.The initial method of fastening the liner resulted in failure of the connections. Subsequent modification to the zinc concentrate bin fastener system proved satisfactory and it has now been in operation for over one year without any separation of the lining material.Utilization of flow testing procedures on concentrate samples has demonstrated that proper design of storage bins or hoppers to achieve continuous flow can be incorporated into the design of new plants."

Jan 1, 1978

By Sergio Cattalani, David J. Kerr, Harold L. Gibson

Abstract - The Horne mine was truly a world class Cu and Au deposit. Between 1927 and 1989, it produced some 260 t of Au and 1.13 Mt of Cu from 53.7 Mt of ore that averaged 2.22% Cu, 6.1 g/t Au and 13 g/t Ag. The total value of Au and Cu production from the Horne deposit at metal prices of US$300/oz Au and US$1.00/lb Cu is an outstanding US$5.2 billion. The Horne mine was also a company builder. After optioning the property from Ed Horne (Tremoy Syndicate) in 1922, the Thomson-Chadbourne Syndicate discovered the deposit in 1923 and quickly grew to become Noranda, one of the world’s premier mining companies. This discovery fuelled exploration and, along with subsequent discoveries in the Val d’Or-Cadillac camps, led to the "economic development" of northwestern Quebec. The Horne deposit influenced and continues to influence genetic models for volcanogenic massive sulfide (VMS) deposits. Early observations at Horne contributed to an epigenetic replacement theory for VMS deposits. The most recent genetic model for the Horne, invoking sub-seafloor sulfide replacement of silicified and sericitized volcaniclastic host rocks within a graben, has subsequently been proposed for another giant VMS deposit, the Kidd Creek mine. The Horne and Kidd Creek deposits show many similarities, such as localization within synvolcanic grabens, long-lived hydrothermal activity uninterrupted by volcanism, sub-seafloor replacement sulfides, stacked sulfide lenses, zone refining, silicified footwall rocks characterized by high positive ?18O values, and association with FIII rhyolites. Notable differences between the two deposits include the lack of andesitic, basaltic or komatiitic flows at Horne, different inferred water depths, high Au content at Horne versus negligible Au, but sub-economic to economic concentrations of Sn, In and Cd at Kidd Creek.

Jan 1, 2000

By S. Fuentes, J. Cáceres

"During the past fifteen years, mines utilizing the block caving method have improved performance and systematically reduced total mining costs.This paper describes improvements in mine design, mine planning, and mine management, including methods enabling the Chilean and international mining industry to ensure cost savings and productivity growth while using the block caving method. These improvements have encouraged the re-evaluation of underground operations at operating and closed open pits, and challenge surface mining applications as the only low-cost mining method. This paper describes a strategy to estimate the optimum open pit to underground transition time during the life of a mine. IntroductionDuring the last fifteen years, block caving mines have experienced huge changes in designs, planning and administration. These changes have permitted operators to drastically reduce costs, improve equipment productivity, and improve overall business performance. As a consequence of this situation, the block/panel caving mining system is challenging actual open pit operations to maximize the net present value (NPV)."

Jan 1, 2004

The JKRBT (JK Rotary Breakage Tester) is a newly developed impact breakage testing device for rapid ore breakage characterisation, and has recently been commercialised after a three year comprehensive validation study, involving five major mining companies and six industrialised JKRBT units deployed worldwide. Comparisons of breakage mechanisms and characterisation data between the JKRBT and the Drop Weight Tester (DWT) indicate that, despite the differences in the breakage modes, the JKRBT can provide statistically similar A*b parameters, by using a data reduction procedure which takes into account the difference in the number of contact points, strain rate and potential for secondary breakage. Feedback from the validation sponsors has indicated higher productivity and better repeatability of the JKRBT compared with the DWT. This better precision, combined with the JKRBT?s wider particle size capability and wider specific energy range, provide a more powerful tool, ideally suited to rapid mapping of ore hardness in geometallurgical and comminution applications.

Jan 1, 2012

By K. Huang, L. Pan

"Darcy’s law has been used extensively to model cake filtration. It is a macroscopic model, in which particle size dominates the kinetics and cake moisture. In the present work, a capillary flow model has been developed from first principles to study the effects of microscopic parameters such as capillary radius, boundary layer slip, disjoining pressure, and surface tension that may be important for dewatering ultrafine particles. Laboratory-scale pressure filtration tests show that dewatering kinetics is strongly dependent on capillary radius, which in turn is influenced by surface hydrophobicity, surface charge, and length scales of particles. The model parameters determined from laboratory-scale filtration tests show that use of a hydrophobizing reagent can greatly improve fine particle filtration due to increased slip and decreased capillary pressure. The kinetics of dewatering kaolin clay is fastest at a pH where the layer-structured particles coagulate with a face-to-edge orientation. The capillary flow model developed in the present work may be useful for designing filters and optimizing operating conditions.INTRODUCTIONIn 2014, Canada produced 2.2 million barrels per day of crude oil from the oil sands resources in Alberta, which is expected to grow to 3.2–4.0 million barrels per day by 2030 (CAPP, 2013). One of the challenges to meeting these projections is the tailings management. At present, the industry uses ?77 km2 of the lands to construct tailings ponds. Significant amounts of the tailings disposed to the ponds are silts and clays that are slow to settle and consolidate, creating problems for reclamation. It is, therefore, the objective of the present work to develop a filtration model that may be useful for developing advanced dewatering technologies that can address the tailings management issues.Darcy’s equation is the governing law for filtration. It was derived as an empirical model by H. Darcy in 1856 while he was studying fluid flow in sand filters (Hall, 1956). Since then, many investigators derived it from first principles. It relates superficial fluid velocity to the pressure drop across a porous medium of known permeability. In filtration, the latter can be related empirically to particle size using the Kozney equation (Yoon, 2005)."

Jan 1, 2016

By R. L. Amelunxen

"In January 1983, Gibraltar Mines Ltd. started an exploratory program on Column Flotation with hopes of improving performance of the Molybdenum Cleaning circuit. The encouraging results led to a column test trial in the Bulk Copper Cleaner circuit where the test unit has per¬formed well. A program was undertaken to understand the mechanics of column operation. A year and a half later, Gibraltar is considering the replacement of existing Bulk Copper and Moly Cleaning flotation cells with a fully computer con¬trolled Column Flotation circuit.BRIEF SUMMARY OF TESTWORKInitial testwork was done with a home made 20 inch diameter x 31 foot high column, equipped with a doppler flow-meter at the tail line and automatic level conrol. This loop maintained constant level in the column by throttling the tail valve. This column was placed in a variety of locations around the Moly circuit as shown on Figure 1 a, b. Test re¬sults indicated that the column could achieve much higher grades than the conventional cells, but recovery wise, the performance was low. Spillages from overloaded pump boxes were a common frustration during this time.Column control strategy was reviewed; and, in light of information received from McGill University, changed to conform with the methods that had been employed by D. Wheeler, of the Column Co. of Canada4 and Gaspe Copper Mines3.The column was tested replacing a portion of the bank, figure lc. The results obtained were more or less equal to the circuit. However, as we had Nitrogen gas connected to the column and not the regular cells, the column was kept in service. With the use of Nitrogen in the column, the usual copper depressant, Sodium Cyanide could be replaced with Sodium Hydrosulphide, hence lower operating cost.As time went on, a 10 inch diameter column was added in series to re-treat the concentrate of the 20 inch diameter column with hopes that the copper content would decrease from 0.6% down to 0.3% in order to save on subsequent leach¬ing costs. So far, results indicate there has been some im-provement, hut we are not achieving 0.3% copper. (See figure 1d)."

Jan 1, 1985

By E. Henry, C. Mayer, H. Rott

Hangingwall deformation monitoring at Kiruna mine is a major concern for Luossavaara- Kiirunavaara AB (LKAB) since underground production is deepening toward the town of Kiruna. In the quest for more effective monitoring techniques, LKAB decided to evaluate the ability of satellite-borne synthetic aperture radar (SAR) interferometry to monitor ground subsidence by generating continuous deformation maps from satellite radar images. While adopted by other geoscience-related industries, SAR interferometry is still relatively untested in the mining industry. This paper describes the basic principles of SAR interferometry and describes how subsidence is monitored at Kiruna mine. The encouraging results are discussed as well as the benefits (continuous deformation mapping, low cost, fast, etc.) and limitations (sensitivity to snow and vegetation cover) of the technique.

Jan 1, 2004

"At the May 15, 2006 and the May 1, 2007 Canadian Securities Administrators (CSA) Canadian Institute of Mining, Metallurgy and Petroleum (CIM) meetings in Vancouver and Montreal, CSA requested CIM consider certain issues arising out of the CSA review of Technical Reports and public disclosure, in general, regarding the practice of estimation and reporting of Mineral Resources and Mineral Reserves. The following is a summary of the issues raised by the CSA and the responses of the CIM.Preamble: At the May 15, 2006 and the May 1, 2007 Canadian Securities Administrators (CSA)-Canadian Institute of Mining, Metallurgy and Petroleum (CIM) meetings in Vancouver and Montreal, CSA requested CIM consider certain issues arising out of the CSA review of Technical Reports and public disclosure, in general, regarding the practice of estimation and reporting of Mineral Resources and Mineral Reserves. The following is a summary of the issues raised by the CSA and the responses of the CIM Reserve Definition and the CIM Estimation Best Practices Committees (the Committees). This information is intended to provide the Qualified Person (QP) with further guidance when estimating Mineral Resources and Mineral Reserves and in preparing a technical report written under National Instrument 43-101 (NI 43-101). Several members of the CIM Reserve Definition Committee, the CIM Estimation Best Practices Committee and some members of the Committee for Mineral Resources International Reporting Standards have reviewed these issues and provide the following commentary.Issue 1. - CSA requested CIM review and comment on the selection of an appropriate commodity price to be used in Mineral Resources and Mineral Reserves estimates.Commodity prices are used in the estimation of Mineral Resources and Mineral Reserves and in the economic analysis of a property. In times of rapidly changing commodity prices, or when prices are at the extreme ends of a commodity price cycle, the QP has a difficult job in selecting an appropriate commodity price.• The selection of appropriate technical variables, including commodity price, is clearly the responsibility of the Qualified Person (QP). The QP must describe the reasons for selecting these variables, including price, in the technical report.• The definition of a ""Mineral Resource"" contains the wording ""reasonable prospects for economic extraction,"" therefore, a QP must select economic parameters, including commodity price, that will result in an estimate of Mineral Resources and Mineral Reserves that have ""reasonable prospects for economic extraction""."

Jan 1, 2003

By M. Lytle

"The Corbin area of southeastern British Columbia has been a coal mining area since 1908. Byron Creek Collieries Ltd. Has operated its Coal Mountain Mine in this area from 1974 until the present. In February 1981, this company was purchased by Esso Resources Canada Ltd.Coal Mountain is structurally complex and standard computer algorithms are not applicable to model the overturned synclinal structures and faulted bedding surfaces. This paper discusses two approaches used by Esso Resources staff to model the geology of Coal Mountain.The first approach projects digitized cross-section data along trend to develop a large data base which correctly approximates the shape of the structure. The spatial orientation of the structure is corrected by merging the generated data set with drill-hole data. The second approach uses digitized cross-section and bench-plan geology to generate a block model of the coal reserve.HistoryThe Coal Mountain Mine, also known as the Corbin Mine of Byron Creek Collieries Ltd. is located 24 kilometres south of Highway 3 in southeastern B.C.In 1905, two American businessmen recognized the coal potential of the area during a horseback tour. The two businessmen, D.C. Corbin and E.J. Roberts, formed the Corbin Coal and Coke Co. to mine and market coal from their newly acquired 6075 hectares of coal licenses. By 1908, the town of Corbin was under construction, a 22.4-km rail spur was constructed from the mine to the main CPR line and the first underground mine began to produce coal. An open-pit operation was also developed at the 1828-metre elevation using a steam shovel loading into rail cars. The company operated continuously until 1935, when a lengthy strike forced suspension of operations.In 1943, the Consolidated Mining and Smelting Company Ltd. (now known as Cominco Ltd.) operated two surface mines to produce coal for its smelters at Kimberley and Trail, B.C. This operation ceased in 1948."

Jan 1, 1982

By W. R. Bacon

"IntroductionTHIS IS a brief discussion of certain regional and economic aspects of the Coast Range of British Columbia. Between Portland canal and the 60th parallel of latitude, only the eastern margin of the Range is in Canada. The solely British Columbia interval extends from Portland canal to Burrard inlet. Personal observations in various parts of this area form the basis for much of this paper.Regional GeologyGranitic RocksSome of the best, most continuous exposures in the Coast Range are found at sea level. Reconnaissance study of the coastline has shown that the Range is predominantly granitic in character, but there simplicity ends, for the term 'granitic' as applied to the Coast Range covers a variety of mineralogical compositions. Actual granite is quite uncommon, occurring mainly in irregular or dyke-like masses that do not achieve batholithic dimensions. It is commonly pinkish, relatively homogeneous, and exhibits few of the deformational features that are obvious in much of this plutonic complex.Most of the granitic rocks of the Range fall well within the compositional limits of quartz diorite and granodiorite. The problem of resolving the great mass of these rocks into smaller coherent units is in general a difficult one. As noted above, granitic rock of uniform composition and texture is found in restricted areas and can be outlined without much difficulty. One such body occurs on the southern shore of Nelson island."

Jan 1, 1955

By J. G. Henning, T. R. Yu, J. E. Croxall

"Test work was carried out to investigate the thermal response of loose and solid rock under varying environmental conditions. The primary interest was to develop a technique that could be used to increase the thermal variation between loose and solid rock for better detectability of loose rock underground with a thermal imaging infrared scanner.A variety of thermal enhancement methods were evaluated both in the laboratory and in the mine environment. Air temperature variation created by the exhaust from diesel driven, mobile mining machinery was studied in detail. When sufficient hot exhaust was supplied to the air, unsteady thermal conditions became more pronounced on the rock surf ace. This allowed a greater percentage of loose rock to be detected by a high-resolution infrared scanner within minutes.The degree of thermal enhancement of loose rock was found to be dependent directly on the thermal conductivity of rock, looseness, air temperature change, and inversely on the size of loose, airflow rate and distance downwind from the heat source. It was also found that an air temperature rise of at least r c, or rock temperature differential of1°C was necessary for minimal thermal enhancement required f or infrared detection."

Jan 1, 1990

By T. Gonzales, S. Thakurdin

The conducting of risk reviews is an essential activity in ensuring safe operating conditions, both during project design phases and for existing facilities. The following paper presents a structured approach to the conducting of risk reviews for existing operations, including descriptions of supporting documentation and guidelines for on-site review activities. The conducting of regular site risk reviews and safety audits is crucial in ensuring the continued safe operation of existing facilities, particularly in the copper industry where numerous processes and unit operations can present catastrophic risks, both in terms of loss of life and financial liability. The structured approach presented aims to provide a logical and comprehensive analysis of risks to align safety-related facilities and procedures with current industry best practice and ensure consistency across multiple client operations. INTRODUCTION The production of copper, whether by pyrometallurgical or hydrometallurgical process routes, carries significant inherent safety risks. Production volumes are relatively large, often requiring complex processing routes, multiple production trains and a variety of supporting ancillary facilities. Furthermore, considering the relatively large size of ore reserves, copper production plants can have operational lives well beyond the typical design duration of 20 years. In this context, the conducting of regular risk reviews is essential in ensuring safe operating conditions and aligning facilities with current industry best practices. Risk reviews and safety audits can take various forms and have various areas of focus. The methodologies and approaches described below relate specifically to catastrophic risks, defined broadly as risks that carry the potential for multiple fatalities and significant financial losses. Focus is given to existing facilities and does not consider the risk-related activities such as hazard and operability (HAZOP) studies conducted during plant design. The structured approach presented aims to provide a guide for effective site- based audits and a logical analysis of risks identified. RISK CLASSIFICATION Table 1 provides a typical summary of the classification of risk types and the associated consequence categories and descriptions. It illustrates the descriptions of a catastrophic risk in terms of the broad categories of Health & Safety, Environment, Financial, Image & Reputation and Legal & Compliance. In terms of the Financial category, numeric costs ranges are often prescribed depending on the financial characteristics of the specific operation and the associated parent company.

Jan 1, 2019

By Kjell Winther

"Hydralift Scanmec introduced early in the eighties a new and different mill design for very large grinding mills. The design described has actually no size limitation upwards and is so far suggested with motor power up to 40 MW. The mill is furnished with gearless ring motor drive transmission. It is totally fabricated, without heavy castings. The first installation, an 8, 1 MW ball mill dia. 6,5 m x 9,65 m length, has been in continous operation in 13 years without problems. Total grinding costs has been reduced with 3 0% compared to traditional smaller mills. Reductions has been achieved in maintenance cost, power consumption, liner wear and grinding media consumption.So far 3 ball mills of the described design are delivered and in operation, one grinding Iron ore and two grinding Nickel ore.IntroductionThe design of mills for mineral ore dressing has basically been unchanged since grinding in mills started some I 00 years ago, in spite of the fact that mills have grown larger and larger. This has resulted in structural and mechanical problems, causing expensive failures and loss of production.Hydralift Scanmec engineers were designing mills for more than 20 years according to the old «rules». As they experienced interest for an increase in the mill size at the time when reports about failing mills were published, they started analyzing the different mill parts to find new solutions. One goal was to only use elements from proven technology in the new design. Two key items were ring motor (wrap around motor)(Isch et al. 1977, Meintrup and Klein 1982, Ranze 1983) and large diameter pad bearings (wrap around bearings)(Fuller 1984), both acknowledged from other industries."

Jan 1, 1995

By Sunil Koppalkar, Liming Huang

"Since late 1980s the research group led by late Professor Andre Robert Laplante at McGill University undertook fundamental studies and applied research of the Knelson Concentrator (KC) and developed a sustainable method to correctly estimate gravity recoverable gold (GRG). In the early time a concept of ‘free gold’ was used, it was defined as the gold that could be separated and recovered from gold ore by amalgamation. Due to health and safety hazards, its practical use had declined. Around 1994, a methodology using a 3-in Knelson Concentrator to measure gravity recoverable gold was established at McGill University. Through more than 10 years’ improvement and optimization, this technique had become a standard method to evaluate GRG for gold ores, gold plant streams and platinum group metals. Until 2006, about 200 GRG tests had been carried out at McGill University for the ores from all over the world. Recently, a modified version of GRG test (short test) with the advantages of reduced processing time and lower cost had been developed for the mundane needs of gold industry.INTRODUCTIONGold gravity recovery has evolved significantly over the past twenty-five years, mainly because of the advent of the Knelson Concentrator (Knelson 1988, 1990, 1992, Laplante 2000). Now, a series of Knelson Concentrators for different applications are manufactured and used in gold industry all over the world (Knelson Concentrators 2004).In 1980s the Knelson Concentrator gained acceptance from mining industry as an effective device for the recovery of gold from grinding circuit. Knelson Concentrator became the obvious choice because of its design features: a relatively long processing time without concentrate discharge (compared to some other centrifuges, such as Falcon Concentrator and Chinese Yunxi Centrifuge at that time), large throughput capacity, treating a wide size range of material, yielding a high grade concentrate with small mass that could easily be smelted. As more and more Knelson Concentrators were accepted in gold industry, mineral processing engineers faced with challenges: what are the separation mechanisms of the Knelson Concentrator? How much gold can be extracted for an ore if a Knelson Concentrator is installed? For answering these questions, a laboratory scale Knelson Concentrator was created."

Jan 1, 2007

By Linda C. M. Elliot, Liangxue Liu

"The deposition of tailings under water is considered to be one of the most environmentally promising and potentially cost effective methods to reduce or eliminate acid mine drainage from tailings. One of the concerns of subaqueous deposition has been that metals may leach into the cover waters, thereby increasing aqueous metal concentrations to higher than acceptable limits. This potential was seen to have an even greater possibility for impact when the tailings are deposited under acidic lake water.The following paper summarizes the results of subaqueous tailings pilot column test work conducted to determine the effects of subaqueously deposited tailings on lake water and tailings pore water. Two types of tailings were tested: high sulphide tailings (pyrrhotite concentrate), and low sulphide tailings (end of pipe slime tailings).Data was collected from five columns over a 13 month test period. The results indicated that a stagnant I 000 mm water cover was capable of maintaining the underlying tailings in a reducing condition. The upwards diffusion of pore water resulted in a pH increase in the waters overlying the thickened pyrrhotite tailings and the pyrrhotite tailings with a shallow cover of substrate. A conductivity gradient between the tailings and the water cover caused a diffusion of salts upwards into the overlying water column. Precipitation noted at the tailings water interface may be related to the precipitation of ferric oxyhydroxides, which resulted in a decrease in Fe concentrations noted in the water cover. Other metal concentrations did not exhibit significant increases in the water cover. A sulphate concentration gradient between the tailings and the water cover may have caused the diffusion of SQ4 from the tailings into the water cover."

Jan 1, 1997

By Steven W. Wilson, Brigitte Lacouture, Nichola A. McKay

"The Aqqaluk deposit is a lead-zinc ore body that lies immediately north of the Main Pit at Teck Cominco’s Red Dog Mine in Alaska. It is scheduled to begin production in 2011 or 2012. A project team was formed in late 2004 to plan and implement an ore characterisation and metallurgical evaluation on the Aqqaluk ore. The main objective of this program was to facilitate the transition from Main Pit to Aqqaluk ore in the Red Dog concentrator. The program will develop a detailed, spatially-oriented characterisation of the Aqqaluk deposit attributes including lithology, ore geochemistry, bulk mineralogy, ore texture, as well as evaluating the metallurgical characteristics of ore hardness, process water geochemistry, bench-scale floatability and mineral liberation in ground feed, concentrate and tails. Developing correlations between the metallurgical response and the ore characterisation data is key to the emerging science of geometallurgy. This on-going program is a technical due diligence study that aims to reduce the risk associated with processing a new ore and to provide predictive information for mining and stockpile preparation.The test work to date has focused on characterising the five ore zones currently identified in the Aqqaluk deposit, namely: Siliceous (sub-divided to High Zn:Fe and Low Zn:Fe), Vein, Median Plate and Baritic ores. It identified a number of challenges associated with surface oxidation, or weathering, of the core samples and outlined a program for future sample collection and storage. Metallurgical testing evaluated ore hardness by a variety of methods. Preliminary floatability studies have been completed and some initial links have been established between the ore characteristics and the flotation response. Soluble mineral weathering products, the relative abundance of pyrite and marcasite and the iron content in the sphalerite grains have all shown a correlation to mineral recovery.As new core is received, both the ore characterisation and the metallurgical testing will be continued with a view to strengthen the existing correlations and develop new links."

Jan 1, 2007