Search Documents

By A. E. M. Warner, A. Vahed, P. J. Mackey

"Since early 2015, the price of nickel has dropped from the region of US$6/pound to current levels of around US$4.60/pound (March 2017), reflecting several market factors, but principally due to lower demand from China. Under such conditions, nickel companies have been under pressure to contain operating costs. In addition, labor and energy costs will continue to rise, while nickel ore grades will likely continue to drop. All major companies now accept the need for climate change action and consequently efforts are being made towards lowering carbon-based emissions. Nevertheless, meeting these challenges can also contribute to higher operating costs without parallel innovative developments - which at the same time, under current conditions, major companies are tending to curtail. In this paper, several productivity improvement opportunities to reduce unit operating costs at nickel sulphide and nickel laterite plants are reviewed. Opportunities include: (a) process technology and energy-type selection, production capability, optimization of process intensity and implementation of newer technologies; (b) improved productivity, equipment availability including maintenance best practice; (c) energy savings and recovery opportunities and use of energy surveys and, (d) process modeling and improved scheduling. Such improvements along with an uptick seen in nickel demand going forward should better position the world nickel industry.INTRODUCTION Nickel is an essential metal to modern society, primarily through its use as an important ingredient in stainless steel. Thus, stainless steel finds vital applications in food preparation facilities, as well as important uses in transportation and industrial applications. Canada has always played an important role in nickel production and nickel metallurgy. In the 1940s and 1950s, Canada supplied over 90% of the world’s nickel. However, this proportion has declined considerably to around 10% of the world nickel supply today. Still, Canada remains an important nickel supplier and contributor to nickel extractive technology. Due to the importance of nickel to society, nickel demand is expected to continually rise. On the other hand, nickel companies have been under pressure to contain production costs amid languishing nickel prices. While demand projections show nickel growth, there are uncertainties in actual levels of future market growth. Ore grades are dropping, while labour and energy costs, which are key cost contributors are rising, hence efforts to lower production costs will generally require innovative approaches."

Jan 1, 2017

By James L. Oleson, Hunter R. Propsom, Kevan J. R. Ford, Robert D. Henderson, Bob Musgrove

"Kinross’ Fort Knox Gold mine, near Fairbanks, Alaska has successfully implemented two major metallurgical continuous improvement projects resulting in growth of gold production and an extension of mine life. In 2009, Fort Knox produced 263,153 oz of gold at a cash operating cost of $543/oz. In 2010, approximately 63% of the gold will be produced from the CIP circuit, 15% of the gold from the gravity circuit and 22% of the gold from the heap leach.In 2009, a 44,000 ton per day run-of-mine valley fill heap leach facility was constructed and commissioned as a cost effective treatment option for low grade ores to supplement the higher grade mill. The heap leach facility will produce approximately 100,000 ounces of gold per year under severe winter conditions. Heap leach gold recovery, based on test work shows 30% after a 55-day leach cycle, with long term ultimate gold recovery targeted at 65%. The paper presents the heap leach design concepts and production data.Additionally in 2009, installation of a Knelson gravity concentrator unit (XD70) was completed. This together with an Acacia intense leach reactor (AILR) has increased overall mill gold recovery from 79.3% to 80.7%. A manual shaking table gold recovery operation has been replaced by batch intensive cyanidation of the high grade Knelson concentrates. Increased removal of coarse gold and difficult-to-leach gold species from the grinding circuit, via the gravity circuit, has improved gold leach recovery in the conventional whole-ore tank leach CIP circuit. The paper presents plant operating data, showing the improvements over the old flowsheet.Focus on the metallurgical properties of the high grade and low grade end components of the Fort Knox ore has resulted in significant improvement to gold recovery."

Jan 1, 2011

By J. K. Afidenyo, J. Osei-Owusu

"The Obuasi Mine of AngloGold Ashanti Limited has been operating the world’s largest Biooxidation Plant at its Sulfide Treatment Plant (STP) in Ghana, using the Gencor Biox® technology since February 1994. The Biox® technology was preferred to other alternative methods of treating refractory sulfide ores such as roasting, pressure oxidation and nitric acid leaching due to among other reasons, its lower capital and operating costs, reduced technical risk, relatively benign environmental impact and its ease of operation and maintenance in a remote location.STP has since commissioning succeeded in operating this technology successfully but not without some operational problems. The Plant has seen a number of upgrades and modifications in its circuits which were motivated by cost, operational and throughput constraints.The objective of this paper is therefore to highlight the mine’s experience in the treatment of its complex carbonaceous refractory sulfide gold ores with emphasis on plant operations and improvements such as the Biox® reactors expansion, flotation concentrate upgrade project and neutralization circuit modifications. The Biox® Plant operating cost is also discussed.INTRODUCTIONThe Obuasi mine forms part of the AngloGold Ashanti Group of Gold Mines. It is located in the Adansi West District of the Republic of Ghana. The mine is primarily an underground operation, although some surface mining still takes place. Ore is processed by two main treatment plants: the Sulfide Treatment Plant (for underground ore) and the Tailings plant (for tailings reclamation operations). A third plant, the Oxide Plant, is used to batch-treat remnant opencast ore and stockpiles, of which there are adequate tonnages to keep the plant operational until 2008.Though reference is made in this paper to the Tailings and Oxide Treatment Plants, the main focus will be on the Sulfide Treatment Plant."

Jan 1, 2008

"Polycom, a new approach to ore processing based on pressure comminution, is obviously a very attractive alternative to conventional processing methods.Since a full-scale pilot plant was commissioned in 1986, more than 125 commercial installations, with capacities up to 1000 t/hr, have gone ahead.Already successfully used in processing cement clinker, limestone, coal, and other minerals, Polycom high pressure grinding results in:o Significantly reduced capital costs, because smaller units can be used m new installations;o Capacity increases of up to 100% in existing facilities; and o Operating economies that include energy savings of 20% or more, and reduced wear parts consumption.1. IntroductionAutogenous or semi-autogenous mills in conjunction with rod or ball mills are used with preference for ore processing. Most ball mills are of closed-circuit design and operate with mechanical classifiers (spiral or rake classifiers) or hydrocyclones. In other words, the ores undergo wet primary grinding, since slurries are required for the downstream separation stages anyway. This paper presents a new grinding system based on high pressure comminution of ores. This grinding process allows:- Energy savings of up to 20 % or more- Capacity increases of up to 100 % and more- Reduction of wear costs- Smaller units for new installation and thus- Reduced investment costsThese advantages are highly interesting for both new installations and conversion projects, particulary in cases where an increasing hardeness of the ore, i.e. rising Bond Work Index, reduces the output of the plants or where the metal assay of the ore decreases and the capacity of the existing systems has to be increased. POLYCOM high-pressure grinding rolls have established themselves with great success already for grinding cement clinker, granulated blast furnace slag, limestone, cement raw materials, coal and other materials.Meanwhile more than 250 high pressure grinding rolls have been installed worldwide. Capacities up to 1.000 t/h with roller diameter up to 2.8 m and drive units up to 2.400 kW are installed."

Jan 1, 1991

Background ArcelorMittal?s (formerly QCM?s) Port Cartier iron ore pelletization operations 2 side-by-side induration furnaces each producing 578 t/h of cured pellets Firing No. 6 fuel oil and coke breeze (in bed) Very large heat losses to be addressed primarily by gas recirculation

May 1, 2011

By E. Fried

Cemented paste backfill (CPB) is an innovative tailings management method that consists in returning considerable amounts of mine tailings into the underground mine openings. The filled stopes thus participate to the ground support that allows maximizing orebody extraction and a safer environment for the mine workers. There are also significant environmental advantages of using CPB. Indeed, up to 50% of the concentrator tailings can be backfilled, leading to a smaller volume of problematic waste materials to be managed at the surface. Once the CPB is placed, or when the mine is flooded at its end-life, the backfill is subjected to underground water flows that may leach and spread the pollutants (mainly metals, sulphates, and acidity) which can contaminate the underground waters. The aim of this study is to characterize the leaching properties of CPB material and to identify the cement phases that ensure the metal fixation. A laboratory procedure was implemented consisting in the preparation of various paste backfill mixtures using sulphide-rich and sulphide-free materials, different types of binder, and mixing waters having various sulphates, copper and zinc concentrations. After 90-days curing time, the samples were submitted to column leaching tests. The CPB materials were flushed each day with 100 ml of deionised water during 100 days. The collected leachates were then analyzed for pH, Eh, electric conductivity and chemical composition. For some samples, a differential acid neutralisation test was carried out. The objective of this experiment is to dissolve selectively the hydrated phases by adding incremental acid concentrations. By analyzing punctually the equilibrated solutions, the composition of the dissolved phases and their metal content can be estimated. The leaching test results showed that the pH of the leachates remains alkaline during the test period. When the pH decreases under 10 (after 30 days), different behaviours in terms of chemical element release (especially for zinc) were observed. During the test, the oxidation of pyrite seems to slow down, probably due to passivating phenomena. Moreover, the differential acid neutralisation test results allowed a better understanding of the CPB mineralogy and the Zn-bearing cement phases. Zinc and the other metals seem to be fixed within a calcium-magnesium silicate.

May 1, 2007

By D. Kong, A. Klyashtorin, L. McGilp, I. Wilson

This work reports on applying iron oxide coated sands media in an experimental permeable reactive barrier to remove uranium species from uranium containing water. A field experiment was conducted at the legacy Gunnar uranium mine & mill site that was abandoned in the 1960s with limited to no decommissioning. The flooded Gunnar mine pit presently contains about 3.2 million m3 of water contaminated by dissolved U (1.2 mg/l), Ra-226 (0.4 Bq/l), and minor concentrations of other contaminants (As, Se, etc.). The water is seeping over the pit rim into Lake Athabasca posing environmental and health concerns. Iron oxide coated sands can be used to immobilize uranium species through an adsorption process. Methods for preparation of hydrous ferric oxide sorbents and their supported forms onto silica sands are described. Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (pXRD) were used to characterize the physical-chemical properties of the sorbent. The monolayer uranium uptake capacity (Qm) was estimated through the Langmuir adsorption isotherm. Adsorption kinetic experiments were performed in a lab environment before moving to a field trial. Based on these lab results and the input on field-scale appropriate geometries, a pilot permeable reactive barrier was fabricated and a field test conducted near the Gunnar pit in June 2019. This pilot test provided technical data and information needed for designing a full-scale permeable barrier based on the iron oxide coated sands, which may be applied for in-situ water treatment at Gunnar and other legacy uranium sites.

Jan 1, 2020

By Christopher F. Gleeson, Roger D. Thomas

"Abstract - Wawa has long been a center of mineral exploration activity and diamonds have been reported in the area since the 1930s. However, diamond exploration did not begin in the area in earnest until 1991. In 1993, Sandor Surmacz and Marcelle Hauseux of Saminex began a prospecting program in the area which culminated in their discovery of the "Sandor" diamond occurrence in an outcrop on the east side of the Trans-Canada Highway. They subsequently optioned the property to Spider Resources Inc. who obtained the necessary exploration permits from Algoma Central Corporation and undertook an exploration program. The diamonds at the "Sandor" diamond occurrence are hosted in the matrix of a spessartite dike composed of actinolite, biotite, and albite. Of the 64 similar dikes that have been sampled and analyzed to date, eight have been found to contain a total of 231 diamonds. Most of the diamonds are of high quality, although they are small.The dikes are non-magnetic and do not have any other geophysical characteristic that can be used to differentiate them from the adjacent country rock. All of the dikes discovered to date have been found by prospecting or by geological mapping by the Ontario Geological Survey. The dikes do not contain pyrope garnet or chrome diopside, two of the commonly used kimberlite indicator minerals. Instead, low Mg, high Cr, Zn-rich chromite, and ilmenites of variable composition, some of which lie within the field of kimberlitic Mg-ilmenite compositions, characterize the diamondiferous dikes. A regional-scale till sampling program for heavy minerals, and geochemical analysis of the <0.177 mm fraction, was used to further define the areas of occurrence of the spessartite dikes and to indicate additional areas for diamond prospecting. Heavy minerals in till that were most useful include: actinolite, chromite, and ilmenite. Geochemical analyses of the dikes show them to contain elevated concentrations of Ni and Cr and to be enriched in Ba, Co, V, Ca, Fe, and Mg relative to the surrounding rocks. Elevated concentrations of Ni and Cr in till occur overlying and down-ice of known lamprophyre dikes."

Jan 1, 2000

By Jochen Franke, Derek D. Lichti

"This paper gives a brief introduction and presents recent enhancements in the MillMapper technology developed for thickness gauging and condition monitoring of liners in grinding mills used for mineral comminution. It also introduces the recent expansion of MillMapper functionality aimed at mill operational optimization. MillMapper uses calibrated laser scanner data captured inside a mill to determine thickness at several million points on all liner surfaces at feed, shell, and discharge ends with millimeter accuracy. Data capture takes nominally 5 minutes, hence interruption to mill operation is negligible.The paper is structured as follows. First, a review of the technology and discussion of recentlyimplemented innovations such as liner change out forecasting, automatic ball charge volume and weight measurement, and automatic mill liner volume/weight measurement for mill operational control or load cell calibration are presented. Combined weight information provides control over load related issues such as load fill levels for relining, or start-up load after reline. Feature descriptions are followed by a listing of the numerous advantages over existing techniques and the benefits to operations. Results from the application of MillMapper are presented throughout.INTRODUCTIONThe need for thickness gauging of liners of grinding mills used for mineral comminution is well known but the task is rarely completed to a satisfactory standard. Liner failure resulting from excessive wear can have expensive consequences. Furthermore, mill performance as well as liner wear are known to be correlated to lifter bar geometry (Napier-Munn et al., 1999; Rajamanni et al., 2005). At present, the following techniques are routinely used to gauge the thickness of mill liners:1. Visual inspection;2. Ultrasonic thickness gauging (for steel liners); and3. Physical inspection (e.g. nail inserted in rubber liners)"

Jan 1, 2008

By Milton C. Graves, Marcos Zentilli

"Gold has been reported from most geological environments in Nova Scotia; however, virtually all production (circa 2,000, 000 troy ounces; circa 60 tonnes) has come from that part of the province to the south of the Glooscap Fault which is underlain by Lower Paleozoic rocks of the Meguma Group. Over fifty concordant sets of quartz-carbonate-arsenopyrite veins have seen production. The host rocks are greenschist-grade equivalents of Cambro-Ordovician flyschoid quartz wackes and shales folded and metamorphosed during the Devonian Acadian Orogeny. The veins were emplaced under conditions of greenschist-grade regional metamorphism and under the same conditions of tectonic stress that later resulted in the regional folds and penetrative, axial-plane slaty cleavage. Rapid filling of hydraulic fractures caused by excess metamorphic pore fluid pressure under Acadian tectonic stress conditions can account for the geometry and paragenesis of these veins.The ultimate source for gold deposits in most greenschist-grade domains remains in doubt, but these domains seem to have had ample gold within them available for mobilization. The work done, to date, on the gold geology of Nova Scotia suggests that regional greenschist metamorphism was an effective mobilizer and a potential concentrator of Au, As, W, Fe and S from these vast reservoirs.In rocks of pre-Acadian age north of the Glooscap Fault, gold occurs as an important accessory in volcanogenic massive sulphide ore, as a minor constituent in other types of basemetal concentrations and in one small concordant group of quartz veins.The post-Acadian metallogenetic domain, which overlies and overprints the two older domains, contains small amounts of gold in many mineralizing environments. Veins, with stibnite and gold, cross-cut crystalline rocks. Disseminated gold is present in basal conglomerates of post-tectonic molasse. Gold has been a by-product of Mississippi Valley-type Pb-Zn-Ba-Sr deposits in Lower Carboniferous sedimentary rocks and has been reported with Pb-Zn-Ba-F in veins which cross-cut Lower Carboniferous and older rocks. Small post-glacial placers have also seen minor production."

Jan 1, 1982

By Adil Aledresse, Louis Mercier, Laxman Amaratunga

"The development of high capacity adsorbents with uniform porosity denoted, MP-HMS (Mercaptopropyl – Hexagonal Mesoporous Structure) using nanotechnology, and their ability to extract gold from solution, is presented. The preparation of highly effective heavy metal ion adsorbents by the incorporation of thiol moieties into the pore channels of mesoporous silica molecular sieves has been the subject of many nanotechnology research investigations. The unique feature of these nanoporous adsorbents is their ability to adsorb gold ions from ultra-low concentration solutions like mine effluent as well as from leached solutions in gold mills. The preliminary studies from laboratory simulated gold solutions show that the adsorption capacities of these materials are also among the highest reported. MP-HMS has shown the capability to adsorb 370 mg gold per one gram of the nanomaterials from Tetrachloroaurate solution (up to 37% of their weight). Experimental studies indicated that the maximum adsorption of gold (as high as 99.9% recovery). The current studies will be extended to investigate the interaction of ionic gold complexes with nanomaterials. Future development of this work may lead to either to replace the conventional CIP/CIL processes or use nanomaterials in tandem with the former, suggesting plausible use of mesoporous material in pulp, MIP or in leach, MIL, as a novel gold extraction process.INTRODUCTIONGold typically occurs at very low concentrations in ores less than 10 g/t or 0.001% (mass basis). At these concentrations the use of aqueous chemical (hydrometallurgical) extraction processes is the only economically viable method of extracting the gold from the ore. Typical hydrometallurgical gold recovery involves a leaching step followed by the separation of the gold bearing solution from the residues, or adsorption of the gold onto activated carbon adsorbent. After elution from the activated carbon the gold is further concentrated by precipitation or electrodeposition."

Jan 1, 2008

"The effective thermal conductivity (ETC) is one of the most important thermo-physical properties of porous media. Due to the lack of higher precision influence of temperature on thermal conductivity, we took 6 groups of experiments on rock samples (including igneous rock, sedimentary rock and metamorphic rock) under different operating temperatures from 20? to 50? by 7 acquisition points. The general equation of thermal conductivity drives the value of it increasing along with the decreases of the temperature. While in our experiments, it is easy to find a singularity among them for each sample. The experimental investigations we attempted to observe and interpret the alteration mechanism. According to the Heat Capacity Theory in solid state physics, this research gives the explanation about the “singularity” from 3 understanding of specific heat, average free path, and thermal conductivity. Our research divided the condition of the rock thermal conductivity into 3 different types. INTRODUCTION The effective thermal conductivity (ETC) is one of the most important thermo-physical properties of porous media(Huang & Han ,1988; Peierles ,1955). This parameter is necessary for analysis of heat transfer(Vaferi et al, 2014;Hans-Dieter & Rudiger,2003). It’s well known that a general equation for ?(T) was set by Sass et al. (1992) which based on the coupled effect of composition and temperature on the thermal conductivity(Jesse et al, 2013; Mongelli et al,1982).The equation was further successfully verified for other rock (Zumrud et al,2010;Abdulagatova et al,2009;Seipold& Huenges,1998).Thermal conductivity is also related to other physical proper ties of porous rock, such as thermal diffusivity, heat capacity(Brettmann et al,2011;Abuel-Naga et al,2008). It is well known that ETC and other thermo physical properties of rock materials are affected by various factors, such as temperature, pressure, mineralogical composition, porosity, stratification, size and shape of the components, and nature of pore fluid, etc. (Tiedje & Guo, 2014; Touloukian et al,1970).The understanding of heat transport processes still requires the knowledge of thermal properties of rocks."

Jan 1, 2015

By G. H. Gale, M. A. F. Fedikow, L. B. Dabek

Rare earth element (REE) data are reported for ores, sul?de-bearing rocks and host rocks from massive sul?de deposits and barren sul?de facies iron formations in Proterozoic volcanic rocks of the Flin Flon-Snow Lake area, Manitoba. Some of the rare earth elements (e.g., Eu), are selectively leached in zones of intense alteration and redeposited together with the sul?des and silicatesin the uppermost parts of the alteration zones and at the rock-water interface. Chondrite normalized REE pro?les of layered sul?de ores and exhalites proximal to the deposits typically have positive europium anomalies and are enriched in light REE. In contrast, barren sul?de facies iron formations exhibit negative or ‘normal’ Eu pro?les. REE data are useful to explorationists in determining the presence of ‘off-hole’ metal-bearing sul?de zones, in distinguishing metal-poor sul?dic layers related to ‘economic’ hydrothermal activity from barren sul?de facies iron formation and in some instances as a means of establishing ‘ore-equivalent’ strata.

Jan 1, 1997

By Nick D. Rose

The Dy deposit is a 21 Mt Pb-Zn-Ag-Au SEDEX-type massive sulphide resource located in the Anvil District, Faro, Yukon. This relatively unexplored orebody lies at a depth of 480 to 920m below surface, dips 20 to 35o and comprises vertical ore thicknesses of 3 to 28m at a 9% Pb + Zn cut-off grade. The deposit has been tested at depth with 63 surface diamond drillholes, but has not yet been explored or developed by underground means. Over the past decade, pre-feasibility investigations were conducted for two separate owners of the property to determine the economic viability of developing an underground mine at Dy. Following these previous studies an assessment was undertaken between 1998 and 2000 to further investigate geotechnical considerations for underground mining. The results and conclusions drawn from this study provide direction for possible future exploration at Dy.

May 1, 2002

By D. Ouellet, G. Gagnon, B. Simser, V. Falmagne

The mining sequence at Noranda’s Bell- Allard mine calls for two mining fronts retreating toward a central pillar known as the Retreat Zone between pyramids A and C. It is clear from numerical modelling and rock mass characterization that the induced stress level in the pillar will exceed the rock mass capacity. A mining plan was developed including the redimensioning of stopes in the Retreat Zone, additional ground support and instrumentation in order to ensure the safety of the workforce and to maximize ore recovery while minimizing production delays. The mining strategy consists in allowing the rock mass to fracture and fail progressively while maintaining control of the existing openings with the appropriate support. A systematic analysis of rockbursting and caving hazards was conducted for all accesses and stopes in order to plan ground support and instrumentation needs.

Jan 1, 2004

By David M. R. Stone

Underground mining in the gold industry is gaining popularity in Nevada, and with it the use of cemented rockfill is becoming mainstream. Even with today?s high metal prices, however, mining companies are very sensitive to the margins they realize, and are constantly looking for ways to reduce costs or improve efficiencies. Given that the backfill is one of the largest cost centers in underground mining, mines are constantly under pressure to reduce backfill costs. This paper will present an overview of the factors that impact cemented rockfill quality in Nevada mines based on the authors many years of consulting experience. Cemented rockfill quality can be linked directly to binder consumption, hence programs aimed at improving quality generally result in lower binder costs, better performance in the fill (hence less dilution), and improved safety. The paper will conclude with the key elements of a comprehensive program of backfill quality assessments and backfill QA programs. Comparative laboratory and minesite data from a number of operating and proposed mines will be presented.

May 1, 2007

By D. R. Tesarik

Researchers from the National Institute for Occupational Safety and Health (NIOSH)1 and engineers from Placer Dome, Inc.2, conducted an underground rockfill span test at the Turquoise Ridge Mine near Golconda, Nevada, USA with the purpose of improving safety and increasing productivity by using a bulk mining method instead of drift and fill. A rockfill sill was constructed by mining and backfilling six adjacent, parallel drifts and then undercutting the sill with a 13.7 m (45 ft) wide and 30.5 m (100 ft) long room. Displacement measurements from vertical borehole extensometers installed in the mine roof and rockfill indicated that the sill remained stable with a maximum vertical deformation of less than 5 mm (0.2 in). These results were confirmed by visual observations and calculations from a validated three-dimensional numeric model of the sill. The numeric model was also used to simulate load on the sill produced by dislodged roof material in the shape of a 11.0 m- (36 ft-) high triangular prism with base measurements equal to those of the sill. Failure in the bottom third of the sill occurred with this additional load.

May 1, 2007

By Y. Yhang, D. C. Sego

ABSTRACT This paper evaluates the potential of freeze-thaw dewatering using Albian mature fine tailings (MFT). Freezing tests were first performed to study the effect of freezing rate on dewatering efficiency. Lower freezing rate resulted in higher thawed solids content and shear strength. Subsequently, large strain consolidation tests were conducted to investigate consolidation behaviour and how it is affected by freeze-thaw. The consolidation behaviour was presented in terms of effective stress versus void ratio and permeability versus void ratio. The results can be used to predict the field behaviour of Albian MFT and optimize the application of freeze-thaw for MFT dewatering.

Jan 1, 2014

By Benoît Plante

La mine Tio (QIT Fer et Titane Inc.) exploite à ciel ouvert un gisement d?ilménite massive depuis 1950, générant jusqu?à maintenant plus de 70 Mt de roches stériles potentiellement génératrices de drainage neutre contaminé (DNC), dont une partie est submergée dans le lac Petitpas, au nord de la mine. Si généralement l?ennoiement des rejets miniers a un effet bénéfique pour limiter la contamination des eaux, cela reste à prouver pour ce qui est des stériles générateurs de DNC. Des essais en réservoirs ont été réalisés afin d?évaluer la réactivité de trois différents types de stériles submergés, qui ont été choisis en fonction de leur teneur en ilménite. Afin d?évaluer l?impact de la matière organique sur la réactivité des stériles submergés, chaque type de stérile est étudié en immersion simple ainsi que combinée à des sédiments prélevés au lac Allard, à proximité de la mine, d?où l?eau utilisée dans les essais a aussi été prélevée. L?évolution des teneurs en Ca, Mg, Si et Ni durant les 8 premiers mois d?étude démontrent que les stériles immergés sont réactifs, mais l?impact de la matière organique demeure pour l?instant difficile à préciser. Tank tests on Tio mine waste rock The Tio mine (QIT Iron and Titanium Inc.) exploits a massive ilmenite ore as an open pit since 1950, producing over 70Mt of potentially contaminated neutral drainage (CND)-generating waste rocks. While the underwater disposal of mine wastes generally show a beneficial effect on water contamination, this method still needs to be approved for CND-generating waste rocks. Tank tests were realized in order to evaluate the reactivity in underwater conditions of 3 different waste rock types, chosen with regards to their ilmenite content. In order to evaluate the impact of organic matter on the reactivity of underwater waste rock, each waste rock type was studied in simple immersion and in combination with sediments sampled at Allard lake, located near the mine, where the water for the tests was also sampled. The evolution of Ca, Mg, Si and Ni during the 8 first months of testing show that the waste rocks are reactive underwater, but the impact of the organic matter is till hard to define.

Nov 1, 2008

By E. Onal, C. Craddock, A. Chapman, M. R. Endsley

ABSTRACT Mining equipment operators must interpret and respond to complex information delivered by technology-centric rather than user-centric systems. The ability to achieve high situation awareness (SA) in the face of this data overload is a key challenge to effective decision-making and information exploitation. Incidents attributed to human error that compromise safety and result in loss of revenue, or even life, are often the result of system designs that overload human cognitive capabilities. This paper defines SA as it relates to the operation of mining equipment and describes the design and preliminary evaluation of a new electric shovel operator user interfa

Jan 1, 2013