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By R. Gutray, J. E. Grainger

This paper deals with the use of a cement-deslimed mill tailings mixture for a scraping floor in cut-and-fill stopes at Madsen Red Lake Gold Mines Limited. It describes the mixing and placing procedures and the precautions used with respect to the floor while mining in the stopes. Details of the mix are presented, and advantages and disadvantages discussed. The paper concludes with a brief outline of the costs.

Jan 1, 1966

The Discrete Element Method (DEM) is a powerful tool for analysing the flow of charge, the energy consumption and the pattern of energy utilisation of a SAG mill. With the development of laser scanning measurement, the detailed internal working surfaces of a SAG mill can now be included in DEM models. Using scanned results for new and worn shell liners for a 32? (9.75 m) SAG mill, it is shown that the feed and discharge lifters have significant effect on the flow of the charge introducing significant threedimensionality. The effects of the resolution accuracy of liner geometry and the lower cut-off of the rock size distribution are explored. Finally, using a matched new and end of life worn liner and operating conditions taken from site surveys, the effect of wear on charge motion, distribution and energy utilisation are evaluated.

Jan 1, 2012

By S. Zekovic

"The paper gives an overview of the economics condition and strategic business challanges of the mining&metallurgy sector and their possible impact on the future development of the Bor basin of copper in Serbian part of Danube Region. Economics and strategic challanges in the mining& metallurgy complex are emphasized by world economic and financial crisis. An analysis of strategic challanges is undertaken by application of a comprehensive development framework approach. Paper indicates that an economics and evaluation of possible impacts of constraints and challenges for the development of Bor basin shows that it must be included in corporative decision, local and regional plans.INTRODUCTIONRisks are characteristic of every strategic development and business decision-making, so their successful management should be a part of the development strategy of the corporation, especially longterm. Due to the growing uncertainty in the general socio-economic environment, “risk management”, risk insurance, risk control, risk culture, risk optimization are frequently talked about. Among the key risks at a corporate level are the financial risks and risks of the regulative framework, especially in the field of environment and land use. In both cases, it is a question of external risks, which the companies need to relativize and successfully manage. Some companies pay more attention to production risks and search for better solutions in that domain which is not enough (Ernst&Young, 2008). Strategic business risks appear mostly on the macro-economic level, from where they should be” transferred” onto the level of sector economics and action level in corporations. Risk management include transferring the risk to other parts, avoiding the risk, preventing hazard, reducing the negative effect or probability of the risk, accepting some or all of the consequences of a particular risk.The research has included perspective and the general market trend and market positioning of the production and copper processing complex in the world; the impact of the requirements and strategic goals of the EU Directive and Kyoto Protocol on the institutional and other adjustments important for business in this sector; the impact assessment of the regulations important for business in the mining and metals sector, and case study of economics and challenges for the development of mining and metallurgy sector in the Bor basin of copper in Serbian part of Danube region. The analysis has included the identification and assessment of the global challenges on the future development of the copper complex in the miningsmelting basin Bor. Presented results in the paper are part of the research project “Sustainable spatial development of the Danube area in Serbia"" (No. 036036), financed by Ministry of Education and science of Republic Serbia."

Jan 1, 2012

By Rita Awwad

Building Information Modeling (BIM) has been gaining a significant edge in the construction industry over the last decade. BIM allows gathering all building information in one shared database that can help all construction entities better understand, integrate and visualize all work progress from inception to operation of the building. The main purpose behind BIM is to bring all project participants together (Client, Architect, Contractor, Consultant) since the initial stages of a project allowing them to cooperate and work as a team in the promise of an increased productivity, reduced cost, enhanced quality and faster delivery. However, a full-fledged implementation of BIM tools and benefits is not yet achieved in the construction industry and remains a debatable issue for researchers and practitioners in the construction field. This paper aims at assessing BIM awareness and usage in the Lebanese construction industry through conducting interviews with contractors, architects and consultants that are key players in the Lebanese market. A comprehensive literature review about BIM adoption in some developed countries and in the surrounding region is also provided in order to better evaluate the Lebanese industry status in comparison with foreign industries. This research sheds the light on BIM awareness of the different construction parties in the Lebanese market, assesses the extent of its current use, identifies the pertaining implementation challenges, and provides recommendations to enhance BIM role in the Lebanese construction industry.

Aug 1, 2013

By Olaf Kessler, Jan Kalich, Michael Reich, Julia Osten, Uwe Füssel

Modern automobile bodies consist of different materials, e.g. aluminium alloys and high strength steels. Mechanical joining, e.g. clinching, is very suitable for joining aluminium and steel sheet. But clinching needs a sufficient ductility, which is no longer supplied by high strength steels. Laser-assisted clinching has been shown, to be able to join aluminium and high strength steel sheet successfully. Thereby the steel sheets were heated locally for short times to increase their ductility. Due to the thermal contact between steel and aluminium sheet the aluminium alloys also achieve a local short-time heat treatment. This fact may cause a significant impact, as aluminium sheet in automobile bodies is often used in T4 (or similar) condition and later artificially aged during the paint bake cycle. Aluminium alloys 6016 and 6181 have been short-time heat treated with heating rates up to some 100 K/s. Precipitation and dissolution processes have been monitored in-situ by calorimetry. Mechanical properties have been investigated on as well as after short-time heat treatment by deformation dilatometry. The results show, that suitable short-time annealing parameters during laser-assisted clinching can increase ductility and at the same time act as retrogression for aluminium sheets, resulting in increased strength after aging.

Jan 1, 2015

By R. Holmestad, M. Gazizov, S. Wenner, R. Kaibyshev, J. K. Sunde

"Mechanical properties and microstructure of an Al-4.7Cu-0.74Mg-0.51Si-0.48Mn-0.10Cr-0.09Ti-0.02Fe (wt. %) alloy subjected to various thermomechanical processing (TMP) have been investigated and compared to conventional ageing at 170°C (designated T6). Three TMP routes involving cold deformation of solution treated samples were tested. These were (i) 3%-stretching (T8-3%), (ii) equal-channel angular pressing (ECAP) to true strain (e) of ~1 (T8-1) and (iii) ECAP to e~2 (T8-2), all with subsequent ageing at 170°C for 0-96 h. At peak age conditions, both yield stress, ultimate tensile strength and elongation-to-fracture decreased for the T8-3% state as compared to the T6 condition. Intermediate ECAP (T8-1 and T8-2) lead to significant increase in maximum yield stress, ultimate tensile strength and elongation-to-fracture. The changes in mechanical properties were related to microstructure evolution, encompassing changes in grain sizes, dislocation densities, precipitate morphology and phase fractions, which were characterised using transmission electron microscopy. Relations between TMP, precipitation behavior and contributions to different strengthening mechanisms are evaluated.INTRODUCTION Al-Cu-Mg-Si alloys are widely used as structural materials in aerospace industry due to their attractive combination of high specific strength, good fracture toughness and enhanced creep resistance. These properties are largely due to the formation of a large number of nano-sized metastable precipitates during artificial ageing (Polmear, 2006; Eskin, 2003; Gazizov, Dubina, Zhemchuzhnikova, & Kaibyshev, 2015). The precipitation behaviour in these alloys is complicated and depends among other things on Cu concentration and the Mg:Si ratio (Wolverton, 2001; Chakrabarti, & Laughlin, 2004). In general, the precipitation sequence has been presented in a prior study (Eskin, 2003) as follows:"

Jan 1, 2018

By M. L. McAllister, M. Veiga

The mineral industry has seen many significant changes in the past decade. Increasingly, it has responded to unanticipated pressures and demands with a variety of voluntary initiatives. Yet there is still much to do. Mining now takes place in a different context than was the case in the past. Socio-economic, political and environmental considerations must now be integrated into traditional mining systems. This process of integration needs to involve industry, governments, academics, communities and other stakeholders to design a new approach to mining, one that can be fostered through interdisciplinary links and holistic strategies. This paper considers the meaning of sustainability in the context of the Canadian mining industry and explores the need for a broader vision for the mining industry. The role of technology is then analyzed and related to an initiative recently taken by Canadian universities to develop a national network for interdisciplinary research into sustainable mining, CaSM.

Jan 1, 1999

By I. Cotman

Dimensional stone processing has become an important part of the world extractive industry, and today?s total stone block yearly production is estimated to be around 134.000.000 tons and is still growing by an average yearly rate of approximately 20%. In future, the same production will become an important part of the mining industry and presently, in some countries it represents even the main mining output. New environmental regulations, together with landscape and nature conservation requirements, create a number of difficulties in setting up new open pit dimensional stone quarries. As a result, many dimensional stone producers have recently started to apply underground techniques in order to produce the ornamental stone blocks intended for further processing. Underground production of stone blocks requires special mining methods and so far it has not been a cost-effective excavation method for all types of rocks. Presently, this type of stone excavation is generally applied in sedimentary and marble deposits because the rock has small to no mineral quartz content. When starting a new underground dimensional stone mine, it is necessary to analyse the impact of all primary factors which are crucial to set up a technically and cost effective advanced underground dimensional stone mine. The role of physical and mechanical properties of the rock, geological conditions, mineralogical composition, micro-tectonic state of the site, rock mechanic conditions on the site, durability and saw ability of the stone are decisive factors in foreseeing the future methods of extraction. The laboratory research work as well as the field work, is very important in decision-making aimed to choose the future excavation method. Also of equal importance is the serious market research, because it renders the indication of selling price potential. Having obtained the results from both types of research, mining engineers can design the mining methods which optimize financial return to the mine. The practice approved by 15 years of testing in the underground limestone quarry of Kanfanar gives future producers very useful advice and general data to facilitate the process of exploration intended to establish new similar underground quarries.

Aug 1, 2013

By A. C. Gagnon, H. Saroglou

"The focus of this paper is on the analysis of geometrical discontinuity properties for the rock mass located within an open pit mine located in Western Africa. Discontinuity data were collected using various techniques including oriented core logging, borehole televiewer surveys, surface pit wall mapping and photogrammetry. The geological setting was initially studied prior to the data analysis to produce threedimensional ground models of the regional and mine site geology along with block diagrams illustrating predicted fracture patterns. Stereographic and statistical discontinuity data analysis of the geometrical properties of the rock mass was subsequently performed to identify unique structural domains throughout the open pit area. The discontinuity data collected throughout the studied open pit area were primarily discontinuity orientation, frequency and spacing and the investigation focused on the reasons for observed differences between the various data collection techniques. Stereographic analysis was used to assess the preferred geometry of discontinuities filtered by lithology, data collection technique, borehole, discontinuity type and pit wall (footwall or hanging wall). The observed fracture pattern is explained adequately by the geological setting. The need for accurate ground models for the design of open pit slopes is highlighted.INTRODUCTIONThe Tasiast Mine is an open pit operation located in north-western Mauritania, approximately 300 kilometres north of the capital Nouakchott. The Tasiast mine, which is owned and operated by Kinross Gold Corporation (Kinross), began commercial operations in 2008. The Tasiast mine is located in an area characterized by flat desert terrain within the western reaches of the Sahara Desert region. The current mine site includes mill buildings, shop facilities, waste dumps, tailings facilities and two main open pit operations (Piment and West Branch). The West Branch pit is the focus of this paper. The current open pit plan for West Branch indicates a final pit measuring approximately 2.5 km long by 1.4 km wide and 510 m deep."

Jan 1, 2015

By B. Chareyre, H. Pourpak, L. Scholtès, E. Papachristos

"Numerical methods used to study hydraulic fracturing in low permeability rock masses need to take into account the interaction between the progressive failure mechanism of the intact rock matrix and the pre-existing natural fractures. A fully coupled hydro-mechanical 3D discrete elements model dealing with such interaction is presented here. The ultimate objective is to grasp the role of the rock-matrix failure on the propagation of the main fluid driven fracture under different stress fields and pre-existing fracture orientations. The proposed method provides the spatiotemporal distribution of the induced crack events which can be tracked during the simulations, making possible the identification of the local mechanisms leading to macro-failure in the rock matrix or reactivation of the discontinuity planes. Fluid flow inside a fracture, pressurized crack and hydro-fracking experimental tests were simulated as part of the validation process of the model and, are presented in this paper.INTRODUCTIONWith the expansion of shale gas and geothermal reservoirs exploitation, the technique of Hydraulic Fracturing (HF) has been widely used over the past years (McClure, 2012; Britt, 2012). Despite recent advances in micro-seismicity analysis or numerical modeling (Nagel et al., 2013), the way progressive failure of rocks affects the fluid flow depending on the in situ stress conditions or the rock heterogeneities is not fully controlled yet (Zoback, 2010).In this work we focused on setting up a three-dimensional discrete elements model to study fluid driven fractures propagation. The intact rock is modeled by a discrete element method (DEM) able to reproduce fracture initiation and propagation (Scholtès and Donzé, 2013, Garcia et al., 2013). The pre-existing fractures are explicitly modeled and can be individually defined or be part of a discrete fracture network (DFN) (Harthong et al., 2012). Their mechanical response is fully coupled with the fluid within a HM-DEM framework. The fluid flow and it’s interaction with the intact matrix and the pre-existing discontinuities is modeled through a Pore-scale Finite Volume (PFV) scheme specially enhanced for fractured rock modeling (Chareyre et al., 2012, Catalano et al., 2014) ."

Jan 1, 2015

By P. E. Cavanagh

THIS REPORT is not intended to be a ?comprehensive survey of the steel industry in Europe. For the past ten years the Ontario Research Foundation has been interested in several developments in the steel industry in Europe which it was felt would be of particular interest in Canada and might possibly find application in this country. This is an account of the present status of some of these developments. The economies of steel making in Canada are somewhat different than in the United States because of the nature of the market and the relative costs and availability of such raw materials as metallurgical coke and electric power. There are cases in Europe where a great deal of effort and money has been spent in trying to make steel profitably by methods which take advantage of locally available and cheap raw materials by modifying standard practices. ln cases wl1ere the investigations have been successful and the data are available to allow translation of the results into Canadian conditions, it is felt that such information may be of great benefit in the future in Canada and at !east should be known to all those in the steel industry in this country. The field to be covered in this report only comprises the steps from concentration and treatment of iron ores to production of iron and is only concerned with those commercially operating processes well known to us and judged to be of present interest in Canada.

Jan 1, 1957

By G. Knight

"Results of a program of dust research carried out at the Mines Branch Laboratory, Elliot Lake, indicate that dust-concentration estimates vary greatly, depending on the sampling instrument, the assessment technique and the properties of the dust cloud. The wide range of the ratio between the estimates by any pair of instruments shows that the correlation between the health hazard and dust-concentration estimates by most existing sampling instruments must be questionable. Important studies are being carried out to permit the definition of mine environments in more precise technical terms. The influence of size selection, the physical property measured, composition and sampling period on the assessment of the health hazard are discussed."

Jan 1, 1969

By H. Hitchen

THE object of this paper is to present the various facts that l1ave been revealed during lengthy investigations into the performance of all types of ropes on different hoisting installations. It then goes on to suggest means by which most of these findings could be usefully employed to obtain more economical rope lives with increased safety. SHAFT HOISTING ROPES Four basic designs of ropes are now employed for hoisting duties: (1) Six-strand, round strand ropes with fibre cores. (2) Six-strand, triangular strand ropes with fibre cores. (3) Non-rotating, multi-strand ropes. 0) Locked coil ropes. Round Strand Ropes (Figure 1) Very solid and reliable ropes can be obtained with this simple geo-metric design of strand. 1'1?iangula1? Strand Ropes (Figure 2) Owing to the fact that the wires in the strands are bent over a triangle, they do not seat quite so solidly as when they are bent over a circular core wire, as is the case with

Jan 1, 1963

By D. B. Dreisinger, D. G. Dixon, G. Nazari

"The kinetics of chalcopyrite leaching in acidic ferric/ferrous sulfate media under atmospheric conditions in the presence of pyrite has been investigated. It has been found that pyrite samples from different sources affect the rate of chalcopyrite leaching differently. A strong correlation between the amount of silver associated with the pyrite and its effectiveness has been noted. In this study, improvement of the catalytic properties of pyrite such that all pyrite samples accelerate the rate of copper extraction regardless of their sources is demonstrated, and a detailed discussion of the mechanisms involved in the process of chalcopyrite leaching in the presence of silverenhanced pyrite is presented. INTRODUCTIONIt is well known that chalcopyrite resists leaching in sulfate media. It has been proved that pyrite facilitates the leaching of chalcopyrite (Berry et al., 1978; Dixon et al., 2008; Mehta and Murr, 1983; Muñoz et al., 2008; Nowak et al., 1984, Tshilombo, 2004). Considering the catalytic effects of pyrite on accelerating the kinetics of chalcopyrite leaching, Dixon and Tshilombo (2005) have developed a new process, known as Galvanox™, which has several advantages over other hydrometallurgical processes. Galvanox™ runs under atmospheric conditions, so it requires only low-cost leaching tanks. The sulfur yield at this temperature is high (>95%) which leads to low oxygen consumption and low sulfuric acid generation. The operating temperature is below the melting point of sulfur which eliminates the use of surfactants. This process also does not require fine grinding. Reaction 1 shows the overall leaching reaction in the Galvanox™ process.CuFeS2 + O2 + 2 H2SO4 = CuSO4 + FeSO4 + 2 S0 + 2 H2O (1)Complete copper recovery from the Galvanox™ process can be achieved at a considerably higher rate than other atmospheric ferric sulfate leaching processes (Dixon et al., 2008). Recycling pyrite and recovering copper from tailings with the Galvanox™ process have also been evaluated in continuous pilot leaching campaigns (Dixon et al., 2007)."

Jan 1, 2012

By J. M. Hemstock, H. L. Ames

THESE forums have been held annually since they were introduced by Mr. L. E. Djingheuzian in 1957. The response of millmen to questionnaires such as the one this year is ample evidence of the interest these create. This year's topic is unlike those of past years since it is an attempt to understand a new concept of grinding rather than to improve the old. Before, we were thinking in terms of 2-5 cents improvement in grinding costs, now we will be discussing savings of 15-2 5 cents. As a background for this forum we will begin by summarizing the major controversial issues relating to grinding with steel, many of which will undoubtedly apply to pebble milling. Our •task to-day is to learn what has already been done in pebble milling and obtain a fair overall view of this method of grinding.

Jan 1, 1961

By Y. M. Shneerson, P. V. Zaytsev, I. V. Fomenko, M. A. Pleshkov

A thermodynamic description of the equilibrium in liquid and gas phases under specific conditions of refractory gold pressure oxidation was generated using the HKF theory. The gold behavior was considered at 190-225°C in the presence of 1-100 mg/L of chloride ion, and under oxidationreduction potential (ORP) of +700 to +1030 mV. The calculations show that the predominant form of gold(I) occurrence is [AuOH]° compared to [AuCl2]?. High ORP favors the formation of [AuCl4]? as a predominant form of gold(III). It is noted that this complex is responsible for the gold losses buildup during POX. Laboratory test results for double refractory concentrate POX are shown. The combined negative effect of (i) organic carbon of the concentrate and (ii) dissolved chlorides in POX slurry on gold recovery is demonstrated. The effects of carbonate blending to the POX feed concentrate and incomplete oxidation of sulfides on POX performance were studied. The pilot tests results of continuous pressure oxidation are also shown and generally confirm the laboratory results and theoretic dependencies. A comparison of the experimental data with the results of thermodynamic calculations is made. As a result of current research, an effective process for POX treatment of carbonaceous sulfide concentrates in the presence of chlorides was developed.

Jan 1, 2014

By M. Matthias

A study, part of a doctoral dissertation (Matthias, 1991), was conducted during 1987 and 1988 to establish the means by which professionals assess and maintain their competence during the various stages of their careers. The study elicited responses from fifty-nine subjects representing engineering, pharmacy and medicine (twenty subjects from engineering, nineteen from pharmacy and twenty from medicine) on their perception and assessment of continuing competence. The findings revealed a wide variation of how professionals perceived their continuing competence and the means they adopted to keep current. The implications of the study are significant for adult education practice and theory building. The author strongly believes that now, more than ever, engineers must take ownership of their careers and professional development activities. While management and supervision have a key role to play, it is the engineer, who is ultimately responsible for the scope, planning and implementation of her/ his professional development needs. An example from one high technology company will illustrate these points.

Jan 1, 1999

By A. Allaire

The Goldex operation of Agnico-Eagle Mines (AEM) commenced operations in the spring of 2008. Following some months of initial operation, the grinding circuit capacity was under-performing according to the original design throughput. BBA Inc. (BBA) was commissioned, in February 2009, to study the different options and recommend the quickest and most cost-effective solution to increase the grinding circuit throughput rate. The mandate was to increase the throughput of the grinding circuit to beyond the original design of 7,000 tpd to 8,000 tpd or greater, while retaining the existing SAG and ball mills. The circuit was modelled using JKSimMet software to evaluate the different options, each with a number of different operating parameters. The option of secondary crushing of the SAG mill feed was retained. Comparison of the different options and simulation outcomes, design of the secondary crushing circuit, operating conditions, and initial adjustments in the design and operating results of the new grinding circuit are discussed in this paper.

Jan 1, 2012

By M. Girard, E. Bourricaudy, M. Ashbury, M. Canizares, A. Mezei

Liquid-solid separation and slurry handleability relate directly to commercial plant ramp-up success or lack thereof. The paper provides a well-proven approach for testing, scale-up and commercial application of difficult processes. Emphasis is placed on practical applications of rheological concepts developed both academically and empirically. The cause-effect relationship between the process chemistry and possible physical implications on the metallurgical plant operability is presented in a simple, direct form. Examples include recent results in areas of mineral processing and extractive metallurgy. Technical process risk factors and their mitigation are included in the discussion.

Jan 1, 2011

By Nabeel Khan

Annual oil production from the Canadian Oil Sands in Northern Alberta has been rising for several decades, and more ore and overburden are excavated each year from an increasing number of open pit mines. Overburden meeting certain specifications will be used to dam tailings and fill open pits, but the remaining material must be stored in overburden storage structures (OBSS). Well-designed overburden storage structures are more stable and cost less in the short- and long-term. The purpose of this paper is to explore OBSS designs that will be stable yet economical in the short- and long-term. The geological background of the site is briefly discussed, including the effect of each of the main geologic layers (recently deposited till and muskeg, Clearwater Formation clay shales, McMurray Formation oil sands, and the Devonian limestone) on the slope stability of the OBSS. Cost is considered in the analysis when balancing between minimizing costs (steeper slopes) and acceptable factors of safety (flatter slopes), all the while considering the financial consequences of failure. Potential failure planes are identified and probabilistic analysis is conducted on the critical failure surface. The variations in the factor of safety caused by varying pore water pressure, friction angle, and cohesion, are plotted and discussed.

Jun 1, 2012