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By Steve Massman, Edward Wipf, Gary Beerkircher

"As mine size and tonnage continues to increase, material handling/processing equipment has also increased in size with 400 MT haul trucks, 2000 KW crushers, 12 M SAG/AG mills, 8.5 M ball mills, 3000 M3 flotation cells and 12.5 MW HPGR’s all with planned designs to increase in size further. Related equipment including vibrating screens have also increased in size with screens seeing feed rates of 3000 MTPH. Open circuit SAG Pre-Crush and closed circuit HPGR flowsheets are becoming more common with large screening requirements. Large multi-slope (banana) or horizontal screens are commonly used for these applications, however as the size of these screens has increased, the number and size of the brute force/overhead exciters has increased but with limitations. An example is a SAG discharge screen that will see surges of material from the SAG mill which overload the screen, reducing the screen stroke or throw causing a large reduction in screen efficiency with excessive fines & moisture in the screen oversize feed to the pebble crushing circuit. This paper will present some actual examples of the use of Two-Mass screens as a solution to these overloading problems and the advantages of Two-Mass screens in other high tonnage applications.Brute Force Drive Compared to Two Mass Drive Vibrating ScreensThe standard single mass screen as depicted by figure 1 is generally recognized in the mining industry. It is characterized by the screen body – labeled as the single mass (Mt) that is supported by isolation springs (Kiso). The stroke needed to process material is obtained by incorporating large eccentric wheels and/or drive boxes (Fb) directly mounted to the screen body via a drive tube."

Jan 1, 2017

By D. W. McDonald, L. M. Heaman, R. A. Creaser, T. Davies, T. Chacko, A. Simonetti

"The Three Bluffs gold deposit is located in the Committee Bay greenstone belt, which forms part of the Rae domain of the western Churchill province, Nunavut, Canada. Gold mineralization is hosted by iron formation of the Neoarchean volcanosedimentary Prince Albert Group, and is associated with silicification (quartz veining) and sulfidation of magnetite and other Fe-rich minerals. Conventional U-Pb zircon dating of a conformable dacite unit within the volcanosedimentary host-rock sequence and a crosscutting diorite intrusion confirm a ~2.7 Ga age for deposition of the supracrustal package. U-Pb monazite dates and Pb isotopic analyses of sulfides were obtained by laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS). A subset of U-Pb monazite (1813.8 ± 8.7 Ma) and Re-Os arsenopyrite (1822 ± 21 Ma) dates, combined with a Pb-Pb secondary errorchron age for pyrite and arsenopyrite (1829 ± 77 Ma), suggest that gold mineralization associated with sulfidation of the iron formation occurred at ~1815 Ma, prior to high-grade (upper amphibolite facies) tectonometamorphism in the Three Bluffs area (D2TB/(M2TB). An ~1815 Ma age for deposit formation is broadly consistent with evidence from elsewhere in the western Churchill province and to the southwest in Manitoba and Saskatchewan for a late Trans-Hudson (1.9-1.8 Ga) gold mineralizing event. The majority of U-Pb monazite ages form a second population at 1780.6 ± 4.2 Ma, similar to the age of the majority of Re-Os arsenopyrite analyses (1763 ± 11 Ma). These dates are thought to reflect the timing of peak M2TB metamorphism. 40Ar/39Ar dating of amphibole, biotite, and muscovite yielded plateau ages ranging from 1723.8 ± 9.0 Ma to 1710 ± 17 Ma, which are interpreted to record the timing of postpeak metamorphic cooling to below the respective closure temperatures for Ar diffusion in these minerals. Le gîte aurifère de Three Bluffs est situé dans la ceinture de roches vertes de Committee Bay, laquelle appartient au domaine de Rae dans l’ouest de la province de Churchill, au Nunavut, Canada. La minéralisation aurifère est encaissée par des formations de fer d’âge Néoarchéen appartenant aux roches volcanosédimentaire du Groupe de Prince Albert; la minéralisation est associée à de la silicification (veines de quartz) ainsi qu’à la sulfidation de la magnétite et d’autre minéraux riches en Fe.Les résultats de la géochronologie U-Pb conventionnelle sur une unité de dacite concordante au sein de la séquence volcanosédimentaire ainsi que d’une intrusion de diorite qui les recoupe indiquent que ces roches supracrustales ont un âge de ~2.7 Ga. Les âges U-Pb de la monazite ainsi que les analyses des isotopes du plomb des sulfures ont été obtenus par ablation laser (LA-MC-ICP-MS). Certains des âges U-Pb obtenus à partir de la monazite (1813.8 ± 8.7 Ma) et des âges Re-Os retournés par l’arsénopyrite (1822 ± 21 Ma), en association avec l’âge indiqué par une isochrone à données dispersées « errochron » secondaire Pb-Pb pour la pyrite et l’arsénopyrite (1829 ± 77 Ma), suggèrent que la minéralisation aurifère associée à la sulfidation de la formation de fer s’est formée vers ~1815 Ma, avant que l’événement tectonométamorphique (D2TB/(M2TB) de niveau élevé (faciès des amphibolites supérieures) affecte le secteur de Three Bluffs. Un âge de mise en place de ~1815 Ma pour ce gîte est compatible avec les données en provenance de l’ouest de la province de Churchill ainsi que plus au sud-ouest au Manitoba et en Saskatchewan qui indiquent la mise en place de minéralisations aurifères à la fin de l’orogénèse Trans-Hudsonienne (1.9-1.8 Ga).La majorité des âges U-Pb de la monazite constituent une seconde population formée à 1780.6 ± 4.2 Ma, ce qui est similaireLà l’âge obtenu pour la plupart des analyses Re-Os sur l’arsénopyrite (1763 ± 11 Ma). Ces âges reflètent probablement l’atteinte du pic métamorphique M2TB.La géochronologie 40Ar/39Ar de l’amphibole, de la bio"

Jan 1, 2009

By Peter Wells, Laxman M. Amaratuga, Todd M. Kanhai

"Certain mining methods (eg. Cut-and-fill) result in the contamination of run-of-mine ore with shotcrete. This shotcrete remains mixed with the ore throughout processing. Experimentation performed by Falconbridge Limited revealed that underground contamination of ore by shotcrete (eg. as little as 1% by weight) has led to ill-effects on the nickel recoveries from the flotation process in the mill. The nickel recoveries of contaminated samples were lower than tests without the shotcrete Contamination.To optimize flotation circuits it is important to know why the contamination has created these effects and also to find a method to abate or remove them. Laboratory testing showed that the age of the shotcrete was a factor in it’s effect on nickel recoveries. Younger aged shotcrete gave nickel recoveries lower than baseline nickel recoveries with no contamination. Older shotcrete gave nickel recoveries similar to the baseline.Literature on other cementitious material contaminations on ore revealed that a possible means of remediating this problem is the use of acid in the flotation. The initial pH in the flotation pulp was designed to be pH 9.2, but with the young shotcrete contamination the pH was in the neighbourhood of 10.5. Acid addition may act as a means of lowering the pH to the optimal operational value. Laboratory test work showed that acid addition brought nickel recoveries closer to the baseline."

Jan 1, 2000

By P. Keating, J. Goutier, J. Ayer

"New, high-resolution geophysical surveys were undertaken over parts of the Abitibi Subprovince, Canada, to help with geological mapping and to promote mineral exploration. Gravity surveys in the Rouyn-Noranda and Matagami areas (Québec) allowed better 3-D mapping of important geological structures, and a multiscale edge analysis of ground gravity data over the Blake River Group confirms that major faults behave at depth as predicted by surface geology. Airborne gravimetry west of Matagami (Québec) helped to identify a new trend south of Lake Grasset that is almost perpendicular to the assumed geological trend of the area. Electromagnetic (EM) surveys, flown in the Chibougamau (Québec) and Bartlett Dome (Ontario) areas, allowed new conductors to be identified at greater depths than were achievable with previously used EM systems. Airborne magnetic surveys were flown in the Burntbush area (Ontario), and other available high-resolution magnetic data were compiled to produce a continuous and homogenous magnetic grid of the Abitibi region.The resulting compilation map clearly shows the locations of dikes, faults, and shears zones, and reveals some fault extensions in areas of extensive overburden. This grid also allows the computation of enhanced maps, such as vertical derivative and tilt maps (e.g., a tilt map shows subtle magnetic features in the Blake River Group that are difficult to see in the total magnetic field or its first derivative). Results from these new surveys show there is considerable value in (1) resurveying areas covered by older surveys, and (2) recompiling data sets from these older surveys."

Jan 1, 2012

By M. Keen

The backfill system at Cleveland Potash?s Boulby Mine places waste filter cake underground in the form of a high concentration slurry in worked out areas of the mine reducing the mine?s environmental impact. The backfill system delivers slurry approximately 1100 m down the mine and up to 11 000 m horizontally underground. The Boulby backfill system is unique in that the placed backfill waste is not used for the usual purposes such as support, pillar extraction or reducing ventilation requirements. It was specifically implemented for environmental reasons. This influenced the design and resulted in some unique features of the system. A previous paper (Wilkins et al., 2004) described the design and commissioning of the backfill system. This paper describes the operational experience with the backfill system and backfill placement since commissioning in May 2003 and looks at lessons that can be applied in other backfill designs.

May 1, 2007

By Hamid Butt

Information Technology ??Advanced Information Technology is dramatically changing information flow within organizations. This enables employees to have information at their fingertips to make informed and prompt decisions. ??Real-time information allows timely analysis, which dramatically reduces cycle times, making organizations faster and more flexible. Business Challenges ??Continual growth of mining and Mine mobile fleet.??Increasing maintenance costs. ??Difficult to identify and troubleshoot equipment problems while equipment is operating. ??New equipment is increasing in complexity and cost. Therefore, each failure results in a greater impact to production and cost. ??Troubleshooting practice is reactive. ??Protect and optimize the use of mining assets to realize maximum business value. ??Maintenance and Operating information is not easily accessible ?no near real-time system that provides complete information.

May 1, 2006

Plan de l?exposé ?? Présentation du site de la mine Restigouche et du mandat confié à Genivar ??Dénoyage de la mine ??Processus d?enlèvement des boues au fond de la fosse ??Utilisation de Géotubes dans le procédé à l?usine de traitement des eaux.

Feb 1, 2008

By L. Lui, A. Cauchon, A. R. Laplante

"The gravity circuit at Les Mines Camchib Inc. consists of two pinched sluices to bleed a feed to one of two 76 cm (30"") Knelson concentrator. The Knelson concentrate is upgraded to smeltable grade with a smaller Knelson (18/30 cm) and a riffleless table. Their tails are column cyanided and washed prior to recycle to the grinding circuit. This paper details size-by-size circuit performance. The Knelsons recover around 90% of free gold (as determined by Mozley Laboratory Separator), even below 37 µm. The sluices are ineffective, with upgrading ratios around 2, but approaching unity in the fine sizes. Much of the effectiveness of the circuit lies in the high gold circulating loads in the grinding circuit, which partly atone for the poor sluice performance, and the ability of the Knelsons to recover free gold. Secondary upgrading recovers slightly above 99% of the primary concentrate gold, 90% of it in a 65% Au concentrate and the balance in a heavily loaded (10 to 20 oz/st) pregnant solution. INTRODUCTIONBackgroundThe operating performance of the mill of Les Mines Camchib Inc. has been described earlier (Laplante et al., 1989). The presence of significant chalcopyrite (1 % and up) makes flotation necessary prior to cyanidation, to limit cyanide consumption and minimize environmental impact. In 1982, the presence of very high gold circulating loads in the grinding circuit lead to the commissioning of a gravity circuit, schematically shown in Figure 1. Gravity recovery of gold has been found beneficial because it increases metallurgical recovery by 1-3% (Laplante et al, 1987), as only part of the flotation tail is cyanided, and economic recovery, because of the lower net smelter return of gold in the flotation concentrate (as compared with the gravity concentrate). The latter increase is estimated, with a net smelter return of 95%, at 1.5% when gold recovery by gravity is equal to 30%. In early 1988, a sampling program was initiated to characterize the behaviour of gold in the grinding/gravity circuit. This paper reports on the results of this study."

Jan 1, 1990

By Jarek Jakubec

The new euphoria in diamond exploration brings with it a need to understand the challenges that new projects can face in different stages of the development and risks that the commercial outcomes from the new projects fall short of expectations. In many cases, the problems are related to a poor understanding of the technical risks and a failure to adequately address them during the course of investigation. Failure to evaluate all disciplines to the same level of certainty could lead to a situation where the important issues are only identified late in the project development, resulting in costly delays and financial difficulties. The diamond projects located in Canadian Arctic, with its challenging environmental, geographical, social, political and geological contexts are especially sensitive to the high variability of the outcome. This presentation highlights some of the technical aspects that could be the leading sources of risk in diamond projects and could ultimately result in inappropriate mine designs, reducing the economic outcome.

May 1, 2006

By K. J. Griffin, G. W. Rosval

"In our increasingly competitive market, attempts to improve productivity by increasing axle loads have placed more severe demands on rails. CP Rail thus requires stronger, tougher, and more wear-resistant rails from steel manufacturers. The choice of any rail steel is always a compromise between technical and economic factors. The technical assessment of a candidate rail consists of laboratory and field testing. Laboratory evaluation of rail steels cannot adequately model many service conditions and must, therefore, be supplemented by long-term field testing. The field testing conducted on CP Rail is the subject of this paper.Long-term, in-track, assessment of candidate rail steels begins with the selection and re-laying of a test curve representative of the intended service with both the candidate rail and a control rail steel (i.e. the present intermediate or premium rail standard). The wear performance of the candidate rail is evaluated, in relation to that of the control rail, using data obtained with a rail profilometer developed by the Research and Development Department of CP Rail. Qualitative observations are also periodically made to evaluate the relative susceptibilities of the two rail types to surface defect formation. Testing continues until stable metal loss patterns are achieved. Relative life predictions are then made and detailed monitoring of the test site is discontinued.CP Rail's in-track assessment program for premium rails has resulted in the establishment of a new CP Rail premium rail standard - low-alloy, head-hardened, rails have replaced high alloy rails. The wear/fatigue lives of these new premium rails exceed those of our previous standard by more than 50%, and they also exhibit excellent weldability. CP Rail will continue to evaluate new premium and intermediate strength rail products."

Jan 1, 1988

By Elmer Stewart, Richard May

"The Central Mukur deposit was discovered by the Semipalatinsk Geological Exploration Expedition (GEE) during detailed searches from 1977 to 1980. Andas Altyn Ltd., a Kazakhstanian gold mining company acquired the property and commenced mining in 1995. In 1998, Andas-Altyn Ltd. became a wholly owned subsidiary of Eurasia Gold Corporation.The Central Mukur gold project covers a linear series of parallel, discontinuous zones of near surface oxide gold mineralization that covers a distance of 7 kilometers and extends past the property boundaries. The oxide gold mineralization is a result of the regional oxidization of a primary sulfide gold mineralization emplaced in a series of shallow dipping thrust faults. Resources as calculated by the GEE are 3.45 mt at an average grade of 1.84 gmt Au in the C1 +C2 category and 7.52 mt at an average grade of 1.80 gmt Au in the P1 category. The Central Mukur Gold Heap Leach Mine consists of an open pit, heap leach pads, and an ion exchange resin gold recovery plant. Limited gold production (<2,500 ounces/year) has been achieved over the past three years leaching run of mine oxide gold mineralization. Gold recovery utiling cyanide to dissolve the Au and ionic resin technology to recover the Au for the leachate is approximately 60%. Loaded resin is shipped to a treatment plant at Almaty where the gold is stripped from the resin, refined and sold.This paper will describe the geology, mining, and processing of the Central Mukur ore. In addition, it will describe what it is like doing business in Kazakhstan and the transition from a Soviet style operation to a more western style operation.INTRODUCTIONThe Central Mukur Mine is owned and operated by Andas-Altyn Ltd. a Kazakhstanian gold mining company located in northeast Kazakhstan. Andas-Altyn is a wholly owned subsidiary of Eurasia Gold Corp., a Canadian public company listed on the Alberta Stock Exchange. The Central Mukur mine consists of a small open pit, and a heap leach operation that utilizes ion exchange resin to recover gold from pregnant solutions. In addition to the Central Mukur mine, Eurasia also owns the Myaly heap leach gold project which is also operated by Andas- Altyn Ltd."

Jan 1, 1999

By J. Asfahani

"The Schlumberger configuration used in geoelectrical sounding is slightly adapted here to obtain reliable data for both shallow and deep penetration depths from the same survey. In this configuration, two kinds of current electrode half-spacings are used: the first enables construction of vertical electrical resistivity sounding (VES) curves for shallow depths (<50 m), and the second for depths =250 m. For a given VES location, two field curves are measured and interpreted using two standard approaches. Practical characteristics of such a modified configuration are illustrated with two field applications in Syria. The first aims to characterize the structure of Quaternary and recent deposits in the Al-Ghab depression region, and the second deals with exploration for phosphatic sedimentary units in the Al-Sharquieh mine. La configuration de Schlumberger normalement employée dans les levés géoélectriques a été légèrement modifiée afin d’obtenir des données fiables à faible et forte profondeur durant le même levé. Dans cette nouvelle configuration, deux types de demi-espacements des électrodes sont utilisés : le premier permet le développement de courbes de sondage de résistivité électrique verticales (REV) pour les faibles profondeurs (<50 m), et le second atteint des profondeurs =250 m. Pour une localité REV donnée, deux courbes de champs sont donc mesurées et interprétées grâce à deux approches standardisées. Les caractéristiques pratiques de cette configuration modifiée sont illustrées par deus exemples d’application en Syrie. Le premier vise la caractérisation de la structure des dépôts Quaternaires et récents de la région de la dépression d’Al-Ghab, et le second traite de l’exploration pour des unités phosphatiques sédimentaires à la mine Al-Sharquieh."

Jan 1, 2009

By G. S. Farnham

Abstract This paper lists the interests of the Physical Metallurgy and Chemical Research laboratories of the Metallgesellschaft, which were visited by the authors, members of a group of Canadian investigators sent to Germany by the Department of Reconstruction in 1945. The Physical Metallurgy Research Laboratory The following information was obtained from Professor E. Schmid, Chief of the laboratories. It is understood that Dr. Schmid is a former Nazi and was to be removed from his post in November (1945). Aluminium Research The laboratories investigated the corrosion resistance of the high-strength aluminium-magnesium-zinc alloys. The same test procedure as used by V.L.W. was followed and Dr. Schmid co-operated closely with Dr. Brenner on this project. Intercrystalline corrosion was combatted by additions of chromium, titanium, or vanadium, and the work in this field parallels that of Dr. Brenner of V.L.W. * Dr. Schmid reports that Bollenrath and Siebert believe that corrosion difficulties with these alloys can be overcome to some extent by heat treatment. He himself was of opinion that the correct answer lay not only in correct alloying but also in correct heat treatment. The heat treatment involved either interrupted quenching or a change in quenching rate from a solution temperature of 500°C. The procedure is either a slower cooling from solution temperature or an interrupted cooling with a holding period at l50°C. Work had been done on piston alloys, the 11-13% Si, 1% Ni, 1% Cu, and 1% Mg being the favoured material. This is called Lo-Ex and is similar to Mahle 124 or KS1275.

Jan 1, 1946

By Malcolm Powell

"The argument has long raged across the oceans as to what the best AG/SAG mill aspect ratio is. The North American practice of a high aspect ratio of two, diameter twice length, through to the South African and Scandinavian practice of an aspect ratio of as low as a 0.5. Within the collaborative P9 AMIRA project the MPRU of the University of Cape Town and the JKMRC of the University of Queensland have been collecting plant data pertinent to this issue over the past four years.The JK SAG mill model developed by the JKMRC is based upon data collected from mills having a range of aspect ratios from 1 up to 2. The maximum mill speed, mill load, and ball filling in the fitted data base were all below the operating range common in South Afr-ica. The extension of the P9 project into South Africa therefore lent an ideal opportunity to collect data in a whole new window of operation that would allow the range of applicability of the semi-empirical SAG model to be greatly extended.At the heart of the differences in aspect ratio is the completely different operating practice for high- and low- aspect mills. The mill filling, mill speed, and recirculating loads of closed-circuit single-stage operation have more influence on the differences in operation than the pure aspect ratio relationship. Relationships for load have been extended to 45% filling, with the modified model showing the measured peak in throughput as the mill filling increases. The ball load relationship now covers fillings of over 30% balls (of total mill volume), thus including so-called SAG-ball mills. The influence of closed circuit operation has been measured. It has been found that a key issue of the high slurry flows associated with closed circuit operation, especially when closed with a cyclone, is the pulp discharge limitation of the traditional grate and radial lifter configuration. It has also been observed that absolute mill length is more of an issue than aspect ratio. Slurry flow along the mill and charge segregation within the load are being investigated on pilot and full-scale mills to provide data for potentially modifylng the perfect mixing model that is used for the SAG mill.Improved understanding of these aspects of SAG mill operation and extension of the JK SAG model to better cover the entire range is allowing serious direct comparison of high- and low aspect mills for the first time. It is the conclusion of the researchers working in this area that there is no one best practice, that in fact mills across the range have their application based on ore type, desired product, available capital and on operating costs. Developing robust designs allows direct comparison of two-stage circuits using high-aspect primary SAG mills, with single-stage closed circuit low-aspect SAG mills. The new operations within South Africa are now considering both circuit types, and data is presented on selections that cover the full range of aspect ratio and operating practice."

Jan 1, 2002

By Salvador Gómez, Rodolfo Espinosa, Jaime Bravo, Leopoldo Gallas

"Compañia Fresnillo, S.A. de C.V. - Proaño Mine, is owned by Industrias Peñoles S.A. de C.V. (Peñoles). The Proaño Mine, is one of the richest silver underground mines in the World, and for this reason, production capacity has always being expanded, based on generated reserves. Reserve generation has not being an easy task as this is a vein type deposit.This paper presents the growing stages at the Concentrator, for about the last twenty years; which can be listed as follows:1.,Increase in capacity from 1,000 to 4,500 tonnes per day, at several stages; on the same infrastructure, and without production interruptions.2.,Addition of a new flotation circuit to recover a zinc concentrate with a high silver content.3.,Installation of a semi-autogenous (SAG) mill, to replace a conventional crushing circuit. 4.,Modernization. Installation of an on stream analyser, an automatic reagent dosification system, 4500 ft3 unit cells, pressure filtration, a closed circuit video system to help process monitoring, an automatic ball addition system for SAG and ball mills, and on-line particle size analysers.5.,Silver recovery from old tailings, installing a 2,350 tonne per day treatment plant.INTRODUCTIONIndustrias Peñoles, S.A. de C.V. (Peñoles)Peñoles’ mission is to add sustainable value to non-renewable natural resources. Peñoles seeks to: build long-term shareholder value; provide customers with the highest quality product services; maintain productive long-term relationship with suppliers; develop and promote the capabilities of their personnel; foster mutually beneficial relationship with the communities in which operates; protect and preserve the environment."

Jan 1, 2002

By Alain Bouchard, Germain Labonté, Jim Barrett

"Mill feed materials that are not run-of-mine ore are often a challenge for mineral processors and tend to accumulate in stockpiles, where they remain unprocessed for many years and become “slow moving inventories”. During a complete re-evaluation of the Clarabelle Mill operation (38,000 ton/day capacity) in 2000, it was concluded that there was an opportunity to assemble a 5,000 ton/day custom circuit to treat such stockpiles in the equipment that remained available during regularly scheduled maintenance shut-downs.This project was part of the larger Mill Redesign Project and involved testing the intended flowsheet under a number of operating scenarios for the first material to be treated: spent refractory bricks. The laboratory focus was on how to maximize returns using the available equipment and reagents.The circuit was successfully commissioned in the fall of 2000. As the brick stockpile was depleted, other potential feeds were evaluated at the laboratory, as well as in the new custom circuit itself. Processing of the spent refractory brick has yielded a significant contribution to the profitability of INCO. Significant opportunities lie ahead for generating more value from other slow moving inventories.INTRODUCTIONIntegrated mining operations tend to have slow moving inventories along the path from the mines to the finished products. Spent refractory bricks from furnaces and converters and furnace bottoms are materials that often end up in long-tern stockpiles. Such stockpiles are a challenge, although they represent small tonnages on an annual basis, because they are unique materials, which cannot be readily brought into the process at a rate anywhere near that at which they are produced, due to the high contents of deleterious components such as chromite or magnesia. Accumulation over years will eventually yield a metal inventory worthy of consideration given the right opportunity, such as availability of spare equipment or peak metal prices."

Jan 1, 2002

By Bernard Jones

LTUG ? A meeting of many mining companies that are using large tires ? Introduction of the mines and size ? Companies go over their usage of tires and performance ? As a group we discuss how the manufactures are doing with supplies and performance (who&apos;s running what sizes and manufactures they are using) ? The mine&apos;s best practices they use (which ones work for them and which ones don&apos;t) ? Where the mines see themselves going in the future ? What type of tire management the mines have in place

May 1, 2009

By Jeff R. Reinson

The Diavik Diamond Mine is producing diamonds from two orebodies, the A154 South and A154 North kimberlite pipes, discovered beneath the waters of Lac de Gras. Innovative dike technology with appropriate water collection and treatment systems allowed Diavik to start open pit mining of the ore bodies in 2002. To allow planning, engineering, and implementation of sufficient water handling infrastructure, reasonably accurate estimates of groundwater inflow quality and quantity over the life of mine are required. Prior to mining, a numerical model using the continuum approach was developed for regional and site wide water management. After approximately two years of mining, groundwater inflows to the pit were found to exceed those predicted by the base case hydrogeologic model. The most likely explanation was flow through Dewey?s Fault zone. As this fault was not explicitly accounted for in the model, a detailed hydrogeologic investigation was conducted to evaluate its geometry and hydraulic properties. A multi-disciplined approach was used and involved core logging, fluid logging, geophysical logging, packer testing, a pumping test, and water quality sample collection. The results of the field investigation were used to update the conceptual and numerical models and to develop a Discrete Fracture Network (DFN) model to address small scale problems such as flow into future underground drifts. The updated numerical hydrogeologic models predict that up to 70 per cent of the groundwater inflow to the A154 N/S open pit is through the relatively narrow fractured rock zone associated with Dewey?s Fault. Consistent with the continuum model, the DFN model predicts that inflow to a drift excavated in Dewey?s Fault will be approximately 10 times the inflow to a drift excavated in competent rock. The DFN model provides a better understanding of the distribution of these inflows on a local scale over the length of the drift.

May 1, 2006

By Benoît Demers

Dans ses opérations de traitement de concentré de zinc, l?usine de Zinc Électrolytique du Canada à Valleyfield génère un résidu minier appelé « jarosite ». Jusqu?en 1998, le jarosite était transporté hydrauliquement dans des bassins construits en argile. Le jarosite sédimenté possède une consistance très molle (impossible de circuler à pied sur le résidu consolidé) avec une eau interstitielle acide contenant des teneurs élevées en métaux. Ces caractéristiques particulières au jarosite rendaient très coûteuses la construction et la fermeture des bassins de résidus. En 1998, Zinc Électrolytique du Canada a implanté un nouveau procédé, développé chez Noranda, dont le principal objectif était de stabiliser chimiquement et physiquement le jarosite. Un nouveau concept de déposition a été élaboré pour le nouveau résidu minier appelé « jarofix ». Les grandes caractéristiques du nouveau procédé et du concept de déposition sont : ? Le jarosite est lavé et déshydraté à l?usine avec un système de filtre; ? De la chaux, du ciment et de l?eau sont ajoutés pour former le jarofix; ? Le jarofix est transporté par camions jusqu?à l?aire d?accumulation; ? À l?aire d?accumulation, le résidu est géré selon un concept d?empilement. L?élaboration du concept d?empilement et de l?aire d?accumulation devait tenir compte des caractéristiques de déposition du jarofix, de sa résistance à l?érosion hydrique et éolienne, de la gestion de l?eau de ruissellement, de la faisabilité de construire les digues de ceinture en utilisant du jarofix durci et de la nécessité de restaurer progressivement l?aire d?accumulation. Le déchargement du jarofix se fait à partir d?une rampe qui progresse avec une pente ascendante pour développer un front de déversement de plus en plus haut. La hauteur du tas de jarofix atteindra 30 m au centre du site. L?aménagement initial de 1998 a inclut une digue d?amorce de 3 m de hauteur, une rampe de déversement de 8 m de hauteur et un bassin pour la gestion de l?eau de ruissellement. Les propriétés du jarofix consolidé dans l?aire d?accumulation sont déterminées annuellement. Le jarofix durci possède la consistance et la résistance d?une argile très raide. Sa conductivité hydraulique est similaire à celle d?un silt et il résiste bien à l?érosion éolienne. Après trois années de déposition, la température du jarofix au milieu du dépôt demeure élevée. Le jarofix durci est facile à excaver et à compacter, ce qui en fait un excellent matériau pour la construction des digues de ceinture en périphérie du site.

Nov 1, 2002

By P. W. Godbehere

"INTRODUCTIONMagnetic mill linings have been developed from an invention by Mr. Bertil Brandt, the originator of the Skega rubber lining. The OREBED magnetic mill lining is a concept in which rubber covered strontium ferrite permanent magnets are arranged on the inside wall of a mill shell so that they attract magnetically susceptible material be it ore, media or tramp, to form a protective layer over the magnets and to serve as an operating surface with indefinite life.Noranda Mines Ltd. through its associate Norcast Division of Noranda Metal Industries formed a joint venture with the inventors to market magnetic mill linings in North America. For the past twelve months trials have been undertaken in conjunction with Orebed Inc. to test and develop these linings for grinding mill applications at the Horne Concentrator. Two independent milling circuits are currently being operated, one treating a siliceous gold ore and the other a copper slag.This paper presents the results of the magnetic lining test programme to date."

Jan 1, 1983