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By A. Quilodran, B. Jakovljevic, T. McCallum, P. Wong

"Rare earth separation by solvent extraction (SX) requires multiple separation plants each consisting of many extract, scrub, and strip stages to separate the individual metals. SX modeling advances have brought benefits to circuit design and process optimization by quickly narrowing test conditions without the need for exhaustive laboratory studies. Modeling can be used to optimize circuit configuration, O/A ratios, and acidities, which allows for CAPEX and OPEX savings. A comparison between pilot plant data and the results expected from modeling is presented for rare earth separations with CYANEX® 572.INTRODUCTIONRare earth separations can be difficult due to limited separation between the elements (Xie, Zhang, Dreisinger, & Doyle, 2014). This requires relatively complex solvent extraction circuits utilizing multiple extract, scrub, and strip stages as well as multiple SX configurations to achieve the desired metal purities. Designing rare earth circuits can be complex, and significant time and testing may be necessary to determine the required staging and optimal conditions.Circuit modeling for rare earth separations has been introduced to the industry using CYANEX® 572 extractant (Soderstrom, McCallum, Jakovljevic, & Quilodran, 2014). CYANEX® 572 is an acidic organophosphorus extractant formulation which has a weaker ligand-metal complex strength than that of the traditionally used phosphonic acid extractants. This allows efficient extraction while requiring a significantly lower acid concentration for stripping (Wang, Li, Zhao, Dong, & Sun, 2015). The reduced acid requirement in strip is expected to provide OPEX savings.The modeling can be utilized to quickly determine the required acidity and organic/aqueous (O/A) ratio for a given separation. It is also expected to reduce CAPEX requirements as optimal staging can be determined, and implemented.CYANEX® 572, combined with modeling, was utilized to produce a purified dysprosium (Dy) stream. To achieve this separation, multiple SX circuits were designed and operational conditions specified to separate Dy from the mixed rare earth chloride feed."

Jan 1, 2016

By Freislich. M., Y. Gordon

"In the changing global market scenario for raw materials for the steel industry, a number of novel iron- and steelmaking process technologies are being developed to provide the steel companies with economically-sustainable alternatives for iron- and steel-making. In addition, the steel industry is also focusing on reduction of energy consumption as well as green-house gas (GHG) emissions to address the crucial subject of climate change. In this context, it is important to assess these critical issues for the alternate iron- and steelmaking technologies that have been developed. This paper presents a comparative evaluation of energy-efficiency and GHG emissions for some selected iron- and steelmaking technologies that are being considered for implementation. In this work, Hatch’s G-CAP™ and En-MAP™ tools that were developed with the main objective of quantifying and qualifying the potential energy savings and CO2 abatement within the iron and steel industry, were employed in the evaluation conducted. INTRODUCTIONThe iron and steel industry continues to transform itself and evolve in the ever-changing global market place – the raw material scenario is constantly changing with respect to quality and quantity (availability), there is stiff competition in both global and local markets, and there is increasing pressure to address global climate change issues, especially since the steel industry is highly energy- and carbonintensive. There is growing importance of steel production in developing countries such as China and India – this means that the steel industry in these countries will play an important role in defining and shaping the future of the industry.Climate change is expected to present new risks to the steel industry with respect to ensuring a sustainable business. Legislators are proposing to limit GHG emission by placing an implicit price on CO2 emission - market-based “cap and trade”, carbon tax etc.. In this scenario, it is important for the steel companies to reduce exposure to climate-related risks and at the same time, find business opportunities within these risks. Thus, there is a need to strategically manage the climate change risks; the key steps to strategically manage climate change risks are presented in Table 1[1]."

Jan 1, 2012

By S. A. Pence, A. I. McCallum, V. de Korompay

"Special salt protection rings containing a water-swell• able, polymeric sealant are in successful operation in Canadian potash shafts. Installed above the Prairie Evaporite salt formation at a depth of 3,000 feet, the sealant is preventing formation water migration into the salt and pressure build-up on the concrete lining of both production and service shafts. The salt protection rings are not under the hydrostatic pressure of the formation water.The chemical sealant in use has the unique property of imbibing water and swelling. •Therefore, any water at• tempting to flow by the seal ring actually produces a tighter seal.The purpose of this paper is to discuss the sealant and its properties and uses. Installation of the material and its operation in two Canadian mine shafts is described."

Jan 1, 1971

By D. Campbell

Mining activity is increasing in northern boreal and subarctic regions of Canada. This is the case in the far north of Ontario, especially in and near the Hudson Bay Lowland (HBL). De Beers Canada opened the Victor diamond mine in the centre of the HBL in 2008, and advanced exploration and impact assessments are occurring to the west in the ?Ring of Fire? for ferrochrome, nickel/copper, iron/ vanadium and platinum-group elements, making it one of the richest mineral finds in Canada in recent years. However, the HBL is also a near-pristine, sensitive environment. Its peatlands forms the third largest wetland in the world and are globally important stores of terrestrial carbon. Human populations in the region are sparse, consisting almost entirely of First Nations communities. Local First Nations also have a strong land ethic and greatly influence mining developments. Through formal agreements, they have insisted on a gold standard for environmental management, including a small mine footprint and the return to representative native ecosystems after mine closure. However, knowledge on the revegetation of subarctic and northern boreal ecosystems is limited. Here, we are conducting research at the Victor mine to develop gold standard protocols for the revegetation of disturbed peatlands and mine waste uplands and present a summary of results. We first tested existing protocols for peatland restoration from southeastern Canada. We collected peat-forming plants from nearby muskeg, spread them sparsely over disturbed peatlands and applied a light phosphate fertilizer, but unlike southern protocols, no mulch appeared to be required to produce a representative cover of peat-forming plants within three years. A bigger challenge is the reclamation of uplands made of mine waste back to representative ecosystems. We first characterized reference conditions for uplands in the HBL, which are scarce in the region. Nearby natural uplands were divided into two classes, interior uplands and uplands along river valleys. Multiple parameters were examined at these sites including soil development, bulk density, soil chemistry in the rooting horizons, plant cover by stratum, plant species composition and dead wood. The mean condition and, more importantly, the range of these parameters allow us to set broad targets for progressive reclamation, which will facilitate success. Finally, we characterized local upland plant species through their functional traits to determine their likely abilities to colonize, grow and contribute to ecosystem processes. A classification of species by these simple functional attributes will help restoration managers to select candidate species to meet different goals at different successional stages (i.e. good versus poor dispersers or establishers). Research into these protocols remain in the early stages, but show promise that gold standards can be achieved to ensure that mining wastes can be reclaimed to productive ecosystems.

Aug 1, 2013

By Warwick Bullen

A hypothetical economic model has been developed for diamond projects in the Canadian Arctic using data from recent exploration and mining projects. The model reflects economic conditions as it applies to the diamond mining industry in the Canadian Arctic at the present time. The economic model captures pre-production expenditures, production data, and post-production costs. Before- and after-tax cash flows are derived from the data along with the relevant economic criteria. From the corporate perspective, the model provides guidance as to the minimum size and/or in-situ value per tonne requirements of targets being sought in order to ensure economic success and probable exploration and development expenditures. From the government perspective, the model provides an indication of income and mining tax revenues that can be expected from a particular diamond project. The model shows, on average, diamond projects in the Canadian Arctic are expensive to explore for and develop, but are economically robust. They generate great economic return for mining companies and significant amounts of tax revenue for governments. The fact that diamonds can be transported directly from the mine site by air makes them particularly attractive targets for mining companies that operate in the Canadian Arctic.

Apr 1, 2005

By A. Ignatow

"A review is made of some of the principal factors and conditions that are, and will be, important to the over-all market climate for asbestos fibre and for the future of Canada's asbestos industry: - health hazard associated with asbestos exposure;- uncertain international regulatory environment for continued asbestos use;- adverse public reaction to asbestos;- product liability/litigation costs (U.S.A. primarily);- promotion of substitution by governments and asbestos user industries; and- minimal product and market development efforts by asbestos producing and consuming industries.In addition, Canadian producers, who export some 95 per cent of their production, face additional constraints:- dramatically reduced integration with asbestos-consuming industries;- 60 per cent of exports to most rapidly declining markets (U.S.A., Europe);- increased competition from offshore producers favourably located to growth markets in developing countries;- increasing production costs;- a strong dollar;- disadvantageous freight rates; and- loss of price leadership and price erosion.Future market trends, as well as prospects for Canada's asbestos industry, will be projected in this paper.Economic FactorsTable 1 presents asbestos fibre production in all countries for the period 1980-82. In certain instances, e.g. U.S.S.R. and China, these are capacity estimates as production statistics are not officially published. The U.S.S.R, by far, is the world's largest producer accounting for some 50 per cent of world production, though most production is consumed internally or by COMECON countries. It is estimated that some 700 plants produce asbestos-containing products within the U.S.S.R.Canada accounts for some 25 per cent of world production though it ranks first in world trade. Other important producers are South Africa Zimbabwe, Brazil and Italy. Since 1979, Canada's asbestos mining industry has experienced a dramatic drop in production and exports of asbestos fibre, as demonstrated in Table 2."

Jan 1, 1985

By V. C. Wansbrough

First, permit me to say with what very great pleasure we find ourselves assembled in this most ancient and honourable city of Quebec. It is a city which we deeply respect as the fountain-head of the culture of French-speaking fellow citizens, and the seat of government of a province which is steadily recording new achievements in Canadian mining. Such achievements prove what can be accomplished when enlightened and progressive government policy, technical and scientific competence, and private initiative pull forward together in harmonious rhythm. It is a most happy and auspicious event also that the guiding control of the affairs of the Institute and of the fine traditions of provincial administration have for the past year been united in the person of our honoured President, Dr. A. O. Dufresne. This year, again, we have bad prepared for us by our hosts a splendid programme of technical sessions and social entertainment. Each year we pay an unspoken compliment to the Institute, expecting as a matter of course nothing but the highest standards in both these spheres. In its annua1, semi-annual, and regional meetings, in the constant activity of its local Branches, the Institute continues with marked success to perform its great dual service, social and educational. We are all its beneficiaries to the extent to which we choose to profit by participation in its affairs. But, one imagines, to none are the advantages of Institute membership more valuable than to young men embarking on their professional careers.

Jan 1, 1951

By Walter I. Nelson

THE geology of the Copper Mountain mine has been ably described by Dr. Victor Dolmage in Memoir 171 of the Geological Survey. Reference is invited to that paper for a more extended description of the geology of the ore deposits than will be given here. The important orebodies of the mine occur in fragmencal volcanic rocks, parallel with and adjacent to the gabbro of the Copper Mountain stock. In the mine area, the contact strikes N.45°W. and dips either vertical or steeply co the southwest. For a distance of 500 feet or more from the contact, the fragmental rocks have been intensely metamorphosed both dynamically and hydrothermally. The dynamic effects are reflected in the foliation and fracturing parallel with the contact, which occurs throughout the mine, and the volcanic rocks within this foliated zone are, in places, highly schistose. Superimposed upon thi.s structure is a system of fine, straight, parallel frac-tures that strike nearly normal to the foliation (and contact) and dip between 65° and 75° to the north; it is with this last-described fracture system that the ore minerals are structurally associated. The fractures are mineralized with bornite and, to a considerably less extent, with chalcopyrite and some pyrite. A notable characteristic is the extreme fineness of the fractures; even in high-grade ore they are rarely larger than pencil lines. The tenor of the ore, therefore, varies directly with the fracture spacing. Replacemcnr of the host-rock between two or more fractures, varying in degree from finely disseminated sulphides to masses of nearly solid bornite up to 18 inches wide and 2 to 3 feet long, is not uncommon in the higher-grade portions of the orebodies. Two structural types of orebody are recognized in local nomenclature: the 'contact' orebodies, so-called because they occur along the contact; and 'outlying' orebodics, which are enclosed in the volcanics. The former arc tabular or lenticular bodies elongated along the strike and dip of the contact. The 'outlying' orebodies are coniform, chimney-like masses roughly elliptical in plan; with depth, their roots plunge at steep angles toward the contact. All of the orebodies are cut by a number of light-coloured granophyre and felsite porphyry dykes. These dykes-the so-called 'mine' dykes -enter the mine area from the north, curve gently southeasterly across the orebodies, and then cross the contact into the gabbro at the south end of the mine. All the dykes dip vertical to steeply east.

Jan 1, 1941

By V. L. Mitsopoulos

This paper provides a summary of tailings disposal techniques and the improvements that have been made through the introduction of thickened tailings disposal. The general properties and characteristics of thickened tailings are described, as is a design process for selecting appropriate technologies for thickening, pumping, transporting and storing tailings. The factors affecting the selection of an appropriate disposal site and operational considerations for the effective utilisation of tailings storage areas are also documented.

Jan 1, 2006

By E. E. Mason

THE Myrtle group of mining claims is situated on Barkerville mountain in the Cariboo mining district of British Columbia, west of the old mining town of Barkerville. An 1,800-foot adit, known as the Shamrock tunnel, was driven in 1935-36 from the Barkerville road and in the general direction of the Myrtle group. It was proposed to enlarge this adit to more convenient section, extend it 2,500 feet int0 Myrtle ground, and from there drive a main entry 3,000 feet along the length of the group. Several laterals were also to be driven off this main entry as part of the tunnel schedule. It was thus originally proposed to drive 5,500 feet of new adit and 1,800 feet of laterals, a total of 7,300 feet of new work. Work was commenced with a bulldozer on April 21st, 1941, cutting a bench on the hillside for a plant site. The power plant was ready for operation on August 8th. Slashing and re-timbering of the old adit rook longer than was expected. It was found that 57 per cent of the length required timbering, chiefly by fore-poling, and there was also trouble in several sections with swelling ground. First round in the new face was taken on September 17th, when a 2-shift daily schedule was commenced. Due to delays in delivery of electrical equipment, it was not possible to add the third shift until November 14th. From then on, a 3-shift daily schedule was maintained with the exception of holidays and fortnightly change Sundays until August 1st, 1942, when shortage of labour caused the dropping of a shift. All work was suspended on August 14th. The ground through which the tunnel passed was such that the driving was often interrupted by the need of protective timber at the face. Further, crews were continuously employed timbering behind the face, and in maintenance of timbered sections in swelling ground. Roughly 980 feet of the new workings are now timbered, about 21 per cent of the total.

Jan 1, 1942

By H. M. Kim, J. Rutqvist, D. W. Ryu

"Demand of high pressurized gas storage in underground rock caverns is increasing. Compressed natural gas (CNG) and compressed air energy storage (CAES) are one of the promising examples after since lined rock cavern (LRC) concept has been verified through in-situ pilot tests. Two key essential concerns of high pressured gas storage in underground rock caverns are mechanical stability of the cavern against high inner storage pressure and the risk of gas leakage from the caverns.In this study, we introduce our results of numerical simulations so as to investigate the potential of monitoring for gas leakage at a pilot facility for CAES in underground LRCs. The pilot facility was constructed at a comparatively shallow depth of 100 m, compared to the previous cases with several hundreds of meters, aiming at validating the feasibility of the LRC storage concept in which inner sealing liners, consisting of steel plate and concrete linings, are installed inside the excavated rock caverns (KIGAM, 2011). Compressed air may leak through either initial defects of inner containment liners such as imperfect welding regions and in-situ construction joints of the liners, or through structurally damaged points of the liners during the CAES operation where compression and decompression of the caverns are necessarily repeated and their structural robustness can be deteriorated.For this perspective, we carried out a coupled thermodynamic and geomechanical deformation analysis using TOUGH-FLAC simulator, and investigated the effectiveness of strain monitoring method in detecting mechanical failure of liners which may provide major pathways of air leakage. We therefore used an equivalent continuum model to relate the localized tangential strain to fracture permeability changes, which was developed in our early work (Rutqvist et al, 2012). In detecting and characterizing the leakage location, we tested a cross correlation technique using the synthetic pressure responses monitored in case of the failure of the inner liners. From the investigations, we showed that tangential strain, rather than radial, monitoring especially at the inner face of the sealing liners can be more effective in detecting the mechanical failure of the liners.In localizing the leakage point, we noted that the interface between the inner liners and surrounding rock may not be perfectly bonded so as to increase permeability through which any leaking air pressure may migrate more dominantly. We also demonstrated that the cross correlation of the time histories of pressure measurement especially at these interfaces can be useful in identifying the leakage point. These results may provide useful information in overall design of monitoring and alarming system of our upcoming CAES pilot facilities."

Jan 1, 2015

By A. L. Valdivieso

"The correlation obtained by plotting pH of maximum adsorption of dextrin versus the isoelectric point of involved metal hydroxides can be used to predict the depressing effect of dextrin on flotation in ""pure"" sulfide mineral systems. Sulfides are strongly depressed by dextrin whenever their surfaces are coated by the corresponding metal hydroxide. The efficiency of dextrin as a depressant is affected by the adsorption of the sulfhydryl collector. Hydrolyzable cations modify this relationship in flotation of sulfide ores. This type of deviation of the real-life systems from the predictions based on the behavior of the pure systems shows the possible ways that could be followed to further improve the obtained correlations. Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by"

Jan 1, 2009

1 INFORMATIONS GÉOLOGIQUES ET PLANIFICATION MINIÈRE La notion de gisement exploitable s'appuie sur les connaissances de géologie, d'ingénierie et tablir la rentabilité en fonction des investissements requis, des coûts de production, et des revenus qui sont tributaires de la demande et des prix des marchés. C'est une notion qui est d'abord diffuse lors de la découverte et de la première délimitation d'un gisement "d'intérêt économique potentiel" mais qui doit se confirmer et se préciser par des travaux additionnels pour devenir de plus en plus quantitative et assurée. 1.1 Informations géologiques Les conditions géologiques varient d'un gisement à l'autre (forme, dimensions, attitude, concentration et continuité -litages, effets de pépites - de la minéralisation). D'autre part, chaque méthodes minière a des contraintes différentes quant aux possibilités de sélectivité d'une part, d'acquisition d'information additionnelle lors du développement de la mine d'autre part. Cette problématique a été résumée au tableau 1, modifié de Vallée et al. (1993) [tableau 5, CIM Bulletin, avril 93, p. 74.].

May 1, 2002

By Xiang-dong and Zhu, Xia-jie Hao, Yi-lin Fan, Quan Jiang, Lian-xing Hu, Xia-Ting Feng, Shao-jun Li

"Columnar jointed basalt (CJB), which typically originates from lava flows, is characterized by a special geological structure. The joint network inside the CJB is self-organized into a rough hexagonal arrangement. The field test and measurement during the unloading excavation showed that the columnar joint sets and other internal joint sets not only are important for determining the mechanical properties of the CJB, but also induced its asymmetric unloading deformation and failure. A constitutive model, which considered mechanical deterioration of both the joint sets and rock blocks, was also developed to simulate the unloading behaviour of the CJB. The crack-confinement supporting method for surrounding CJB was developed to overcome the failure of columnar jointed rock mass in the diversion tunnel. Application to the CJB segments of the diversion tunnels in the Baihetan project indicated that this supporting method was reasonable and efficient. INTRODUCTIONColumnar jointed basalt (CJB) rock mass, which typically originates from lava flow, is characterized by a special joint structure. The joint network of the CJB is self-organized into a roughly hexagonal arrangement and leaves behind an ordered colonnade. The widely accepted current view regarding the formation of columnar jointing involves a thermally induced contraction–cooling mechanism (Peck and Minakami, 1968; Degraff and Aydin, 1987; Budkewitsch and Robin, 1994; Lore et al., 2000; Goehring et al., 2006). Although the columnar basalt formation mechanism is fairly understood, the geotechnical characteristics of such rock mass are not well established. In practice, joint sets always induce the multi- failure modes of surrounding rock in the tunneling space (Ibarra et al., 1996; Waltham and Swift, 2004; Mahendra and Bhawani, 2008).According to conventional wisdom in rock mechanics, structural joints affect the mechanical response of rock mass by introducing strong anisotropic effects (Barton and Bandis, 1980; Hudson and Priest, 1983; Brady and Brown, 1985). The columnar jointed rock mass should be considered an anisotropic material given that the joint sets are distributed with some principal directions and characteristic spacing distributions (Cundall and Fairhurst, 1987; Hoek et al., 1998; Wu and Wang, 2001; Budetta and Nappi, 2011; Fortsakis et al.,2012). Columnar jointed rock mass would result in structurally controlled failure patterns, even serious disasters during underground excavation because of the low shear and tensile strengths of intensely joints (Gencer,1985 ;Ishida and Uchita, 2000; Jia and Tang, 2008). The CJB rock mass in the Baihetan hydropower station has exhibited serious stability issues, including sliding, fracturing and even collapse (Shi et al.,2008). Therefore, the geotechnical and geomechanical characteristics of such rock mass should be assessed through in situ investigation and numerical analysis to minimize future accidents during underground unloading excavation."

Jan 1, 2015

By I. Yutronic

Compañía Minera Doña Inés de Collahuasi's (CMDIC) Concentrator Plant is located at 4300 meters above sea level, approximately 2000 kms north from Santiago, Chile. The concentrator has three grinding lines. Each one, Lines 1 and 2, have one SAG mill at the primary grinding stage followed by a secondary grinding and classification stage consisting of one ball mill, two hydrocyclone batteries and a sump with two pumps. Line 3 has one SAG mill (Gearless Mill Drive), followed by a secondary grinding and classification consisting two ball mills, four hydrocyclone batteries and a sump with four pumps. Average throughput for these three lines is 150 Ktons per day. Peak values of 180 ktons per day have been achieved. Since late 2008 and throughout 2009 and 2010, Operations and Automation areas developed an optimization program for the grinding process, considering the implementation of Model Predictive Controllers (MPC) for the three SAG mills, and later, extending MPC to the secondary grinding and classification stages. The implementation of a MPC solution was based on stability considerations (high variability of the SAG process, high interaction between sump level control and classification efficiency, etc), requirements for an automated and consistent operation, the need to maximize throughput under timevarying scenarios and, in the long term, optimization of grinding process considering Specific Energy Consumption, among other parameters. MPC solutions had proven control robustness and strong optimizing capabilities in terms of helping in discovering new operational points and so achieving all of the aforementioned goals. On the first stage of the program, MPC implementation considered identification of dynamical process control models based mainly on historical data, in order to know the impact of a group of Manipulated Variables over Controlled Variables. Also, the impact of measured Disturbance Variables was modeled in order to take into account the high impact and interaction of these variables over the processes. At the end of this stage, 4 controllers were successfully operating for the 3 SAG mills and the secondary grinding and classification process. In response to challenges made by the working group, the second stage of the development of control applications in the grinding process required to achieve a design and implementation of a solution capable of governing the milling process, in addition to stabilization and optimization of both processes (SAG milling and secondary grinding), to integrate from a point of view of process control and automation. Therefore, in the second stage, MPC performance was continuously monitored and optimized through advanced tuning, inclusion of more process models (with proper step tests), redefinition of specific optimization criteria and adjustment to new process needs. Finally, successful MPC implementation at Collahuasi has proved that fast development and deployment of process control solutions is possible and allows immediate process stability, higher throughput, specific energy consumption reduction, and successful product size control, among many others.

Jan 1, 2012

By Phil A. Keele

"IntroductionGeneralThe Genesee Coal Mine is a joint venture of Fording Coal Limited and the city of Edmonton. The mine supplies thermal coal to the Genesee Generating Station operated by Edmonton Power and is located approximately 75 km southwest of Edmonton (Fig. I).Under the terms of the joint venture agreement, Fording Coal Limited has designed and developed the Genesee Coal Mine. Fording also operates the mine which has a minimum economic life of thirty-five years. Mine development started in the spring of 1987 with the construction of the dragline erection pad and mine service complex. Major development of mining areas was carried out in 1988 with the construction of haul roads, powerlines, topsoil recovery, etc. Mining officially commenced on December 14,1988.The mine produces 1.6 million tonnes of coal per year and employs 65 people. MiningGround conditions have turned out to be very poor, as expected with the majority of the overburden in the first few years a soft lacustrine clay with minor amounts of fine-grained glacial till. To compound matters, what was expected to be a relatively uniform coal subcrop turned out to be a very irregular erosional contact.The coal mined at Genesee is a sub-bituminous Class B thermal coal with approximately 16070 ash, 21% moisture, 8300 Btu/lb and 0.27% sulphur on an as-mined basis.The primary piece of mining equipment used at the Genesee Coal Mine is a M8200 walking dragline. It has an effective operating radius of 100.6 m, a 50.5 m3 bucket, and weighs approximately 3860 tonnes yielding a ground pressure of III KN/m2•Figure 2 illustrates schematically the single pass mining sequence presently employed at the Genesee Coal Mine. The M8200 is used to lift all coal out of the cut, the coal being placed in stockpiles on the prepared pad .This method maximizes coal recovery under the conditions where spoil failures due to poor material would otherwise put men and equipment at risk. The coal is subsequently loaded by the coal shovel operating on the same bench as the M8200 dragline and delivered to the plant as required.All mined areas, as required under Alberta Legislation, are to be returned to an agricultural land capability equal to or better than that which existed prior to mining. Reclamation activities, as a result, are an important and integral part of the mining process. A complete list of the primary mining equipment deployed at the Genesee Operations appears in Table I."

Jan 1, 1994

By X. T. Feng, Y. H. Hatzor, Y. Tal, G. Yagoda-Biran

"When studying jointed rock mass deformation around underground openings it is of great importance to model correctly the excavation sequence during the numerical simulation. This is because for effective arching mechanism to develop in the roof minute block displacements must take place and some of the available discontinuities shear strength must be mobilized. If from the beginning of the simulation the underground opening already exists in the numerical model, block displacements into the excavation space will initiate and develop from time zero, before the initial stresses in the model have attained their actual initial level in the field. These initial block displacements are therefore artificial and exist only in the numerical model, not in the physical reality, and may lead to erroneous assessment of the stability of the designed structure, typically on the conservative side. We have introduced sequence excavation capabilities both in the numerical manifold (NMM) and the discontinuous deformation analysis (DDA) methods and show here the advantages of this modification using three different case studies, each illuminating a different aspect of this enhancement.We begin with the 25 meter deep 2000 year old underground Zedekiah limestone quarry below the old city of Jerusalem, Israel, which is still standing today unsupported with a free span of 40 m. We show that when the opening exists from the beginning of the numerical simulation the required friction angle for roof stability is 25 degrees, whereas when the opening is removed after all stresses and displacements in the model have been stabilized the required friction angle for stability is only 15 degrees.We then model the excavation sequence of a tunnel model representing a 2500 meter deep research tunnel in the Jinping hydroelectric project, China, in order to determine the in situ stress field at this depth by a grid search inversion of displacement data obtained using the sliding micrometer technology in the course of tunnel excavation. Thus we are able to constrain the in situ stress field at these depths where standard in situ stress measurement procedures are extremely difficult to execute properly.Finally, we use sequence excavation modeling capability to find the total height of the expected loosening zone around tunnels excavated through columnar jointed basalts which pose a great engineering challenge because of the characteristic dense network of slender prismatic blocks that transect the opening at a steep inclination. We use MPBX data obtained during excavation of a deep tunnel through such a rock mass to validate our numerical results and show that application of standard empirical guidelines for dimensioning rock bolt reinforcement in such rock masses may in fact result in very un-conservative design because existing empirical approaches typically ignore the anisotropic nature of the structure of such rock masses which, as we show, plays a very significant role in determination of the extent, shape, and geometry of the loosening zone around the opening."

Jan 1, 2015

By L G. White

During 1958, prospecting parties working for the Mackenzie Syndicate in the Flat River area of the Mackenzie mountains, Northwest Territories, identified tungsten mineralization and located the property now being developed by the Canada Tungsten Mining Corporation Ltd. Scheelite mineralization, associated with pyrrhotite and minor chalcopyrite, occurs in lime silicate skarn replacement zones within a limestone-chert-argillite series intruded by granitic dykes originating from the ? main batholithic mass underlying the sedimentary beds. The results of surface outcrop sampling and 15,000 feet of grid-pattern diamond drilling have been combined to outline an orebody estimated to contain 1.32 million tons, grading 2.51 per cent WO after applying a 10 per cent dilution factor for mining purposes. T HE property of Canada Tungsten Mining Corporation Ltd. is located in the upper Flat River area of the Mackenzie mountains, Northwest Territories. Skarn-type replacement deposits containing scheelite mineralization are .situated between elevations of 4,500 and 5,500 feet above sea level along the east flank of the mountain range forming the boundary between the Yukon Territory and the Northwest Territories. The nearest supply center for the area is Watson Lake, Yukon Territory, located at Milepost 635 on the Alaska Highway.

Jan 1, 1963

By E. De Souza

The instrumentation and monitoring of rock behaviour have played an important and necessary role in the practice of potash, rocksalt, gypsum, trona and coal mining. The art of rock instrumentation applied to soft rock and coal mining has progressively evolved over the past years and will surely continue to advance at a faster pace in the future as a result of the technological revolution we experience today. The development of sophisticated mine-wide data communications systems is being used for instrumentation and sensor automation, and laser, sonar and geophysics technology are being continuously adapted for rock monitoring purposes. In this paper, the author provides an overview of typical rock instrumentation used today and offers some views of the progressive evolution in rock mechanics instrumentation sophistication and design.

Jan 1, 1998

By Young Hyun Paik, Hyung Sup Choi, Yeun Sik Kim

The basic studies on the surface properties and flotation characteristics of ilmenite were made by electrophoretic, adsorption, contact-angle and floatability measurements. The isoelectric point of ilmenite is found to be at pH 5.6. By combining the results of electrokinetic studies and adsorption measurements, a clearer picture of the ilmenite-solution interface was observed. These findings were correlated with the floatability of ilmenite obtained by Hallimond tube tests. The general flotation characteristics of ilmenite are compared with those obtained for magnetite and rutile. It is indicated that the above three minerals, namely, ilmenite, magnetite and rutile, have very similar surface properties and flotation characteristics. Therefore, it is difficult to make an effective separation of these minerals by flotation. However, it is found that sodium orthophosphate acts as a selective depressant for magnetite in anionic flotation. Therefore, close pH control of the pulp in the presence of the phosphate ion enhances the possibility for a successful separation of these minerals.

Jan 1, 1967