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By M. Kawata, T. Amano, T. Miyamoto, K. Shibayama

"The High Pressure Acid Leach (HPAL) plant of Taganito HPAL Nickel Corporation (THPAL), located in Taganito, Philippines, with a nameplate capacity of 30,000 Ni-t/year started commercial operation on October 2013. The plant load was smoothly ramped up and it achieved monthly production equivalent to 33,000 Ni-t/year in 2016. Partial improvement of the plant capacity for the achievement of 36,000 Ni-t/year, as evaluated from the current operation progress of each system is planned for 2017. In this paper, aside from presenting the progress of the plant ramp-up, research and development activities such as the reduction of nickel loss and the improvement of filtration capacity which was achieved by particle size control of ZnS precipitates in the Zinc Removal system are also discussed.INTRODUCTION Taganito HPAL Plant Project History of THPAL Taganito HPAL Nickel Corporation (THPAL) was incorporated in August 2008, as a joint venture of three (3) companies, namely Mitsui Corporation with 15% share, Nickel Asia Corporation (NAC) with 10% share and Sumitomo Metal Mining Corporation (SMM) with a controlling stake of 75%. Aside from its capital share, NAC’s Taganito Mining Corporation (TMC) supplies the ore for the HPAL plant located in Taganito, Claver, Mindanao, Philippines. The objective of THPAL is to produce 30,000 MT of nickel and 2,600 MT of cobalt as mixed (Ni/Co) sulfide by treating nickel laterite ore in the Philippines and exporting to Japan as raw material for SMM’s Niihama Nickel Refinery (NNR) for the next 30 years. In other words, 1.15 wt% of nickel in ore is refined to 99.99 wt% nickel in electrolytic nickel. The mixed (Ni/Co) sulfide is shipped to NNR and SMM provides the technology and management personnel to THPAL plant as well as sulfuric acid which is the main reagent for HPAL process. Figure 1 shows the location of THPAL and current relationship between the stake holders.The Characteristics of THPAL Plant In terms of plant design, a 2-train system is applied for the HPAL circuit considering the reliability of the process, facility and avoidance of whole plant shutdown due to HPAL troubles. The technical data, operation know-how and improvements gained from the successful operation of Coral Bay Nickel Corporation (CBNC) which was established in April 2002 were reflected in THPAL’s plant design. As for the H2S plant, a more economical design was considered which is different from CBNC."

Jan 1, 2017

By M. S. Badollet

"IntroductionASBESTOS FLOATS may be defined briefly as blends of air-borne particles of fibrous asbestos and dusts produced during the milling stages and collected by Cottrell precipitators, dust sheds, or bag-houses.The various grades of asbestos floats on the market contain fibrous asbestos particles ranging in length from microscopic to approximately 1/4-inch. The fines or dusts present in the floats are from 40 microns to 2 microns or less in cross-section.Airborne asbestos particles are of diverse length because they are collected at numerous places in the mill. There are: (1) dusts removed from dry rock storage bins, (2) dusts removed from rock and fiber screens, (3) particles from the tops of collectors, and (4) fines removed by suction from the processing equipment. Sometimes the airborne particles are kept segregated, so that there is a partial separation by gravity. This is accomplished by a series of dust chambers enclosed in a long, rectangular building. The longest and heaviest particles fall nearest to the air flow entrance, the smallest at a point farthest away and nearest the exit. Sometimes the air from the dust chamber building is passed through a series of bag-houses or electric :precipitators ,to collect the extremely fine particles which normally escape to the atmosphere."

Jan 1, 1952

By T. Sugawara, S. Hara, Y. Mitsui

Surfaces of rock slopes in cold regions often become frozen in winter. Therefore, understanding time-dependent behavior of frozen rock, as well as that of unfrozen rock, is important for long-term stability assessment of rock slopes. In this study, a series of uniaxial compression tests and creep tests were carried out on Shikotsu welded tuff under dry and water-saturated conditions at -20 °C to clarify timedependent strength and deformation of the frozen rock. The influence of water content on them also was investigated. It was found that the amount of deformation of the water-saturated specimen was much greater than that of the dry specimen. It also was found that the creep behavior of the water-saturated specimen was similar to that of polycrystalline ice. These show that deformation of the water-saturated specimen is strongly affected by pore ice. The UCS of the water-saturated specimen was approximately equal to that of the dry specimen at a strain rate below 4.2×10-6/s, and its value was about 17 MPa. However, the former increased up to 26 MPa at 4.2×10-4/s with loading rate, whereas there was little increase in the latter. This means that the UCS of the water-saturated specimen was always greater than that of the dry specimen at higher strain rates. The creep life of water-saturated specimens was longer than that of the dry specimens at stress level greater than 15 MPa. These results of UCS and creep life show that inclusion effect due to presence of pore ice plays an important role on strength of the water-saturated specimen. Creep life of the non-failure specimen that was loaded for more than three days was estimated by the relationship between creep life and axial strain rate at 10 s on failure specimens. It was found that creep life of the water-saturated specimens was shorter than that of the dry specimen at stress levels less than 14 MPa. This suggests that estimation of creep life of frozen rock under water-saturated condition is important for the stability assessment of frozen rock slopes. It was clear that the loading-rate dependency of UCS was related to the stress-level dependency of creep life in both dry and wet conditions. This indicates that there are common fracture mechanism in creep and uniaxial compression tests. It also indicates that the creep life can be estimated by the relationship between the UCS and the loading rate. The time dependencies of the water-saturated specimen were in good agreement with those of polycrystalline ice. This confirms that pore ice strongly affects the strength of the water-saturated specimens as, well as the deformation behavior.

Jan 1, 2015

By W. J. Farley

Location and History The Sherritt Gordon mine is in northern Manitoba, one hundred miles north of The Pas and forty miles northeast of Flin Flon. The original discovery was made by a Cree indian, Philip Sherlett, in 1922. The claims lapsed in 1924 to be re-staked and optioned by various mining groups who carried out a certain amount of development work before relinquishing their options. In 1927 the present Company, Sherritt Gordon Mines, Limited, was formed to take over the property. Production commenced in 1931, but in the following year operations were suspended and it was not until 1937 that the prevailing price of copper pemitted resumption as an economic operation. The mine has operated continuously from that time to the present. Total production to the end of 1947 has been: Copper . . . . . . . . . 301,813 . .,345 pounds Zinc . . . . . . . . . . . 112,636 tons of concentrat (50% zinc) Gold . . . . . . . . . . 83,070 ounces Silver . . . . . . . . . 2,651,317 ounces General Geology The consolidated rocks in the vicinity of the mine, all of Precambrian age, are a series of gneisses and form a part of a great area of what are known as the Kisseynew gneisses. The Sherritt is the only known economic base-metal deposit to occur within the Kisseynew series. Extreme metamorphism has produced recrystallization that has imparted a decided igneous-like texture to many of the units. However, the gneisses are predominantly of sedimentary original although the most basic member, a hornblendegarnet gneiss, is considered to be an altered basic flow. Figure 1 illustrates the intricately folded structure and the succession of roe types. The footwall enclosing members are of sedimentary origin and represent quartzite and arkosic and greywacke derivatives. The contact footwall member is gneissic quartzite, a medium to coarse grained rock composed mainly of quartz with minor altered feldspar (orthoclase and plagioclase), muscovite, chloritized biotite, and magnetite. Most phases of this unit show varying degrees of granitization.

Jan 1, 1949

By Wayne N. McKee, Scott A. Lewis

"Introduction to the Syncrude OperationSyncrude Canada Ltd., located 42 km north of the city of Fort McMurray, Alberta, (Fig. I) is an integrated operation that has produced synthetic crude oil from the Athabasca oil sand deposit since 1978.The operation, consisting of a surface mine, an extraction plant, a bitumen upgrader, and a utilities plant, is currently capable of producing over 60 million barrels of crude oil per year. Production is expected to increase to 70 million barrels of crude oil per year over the next five-year period with no major changes to equipment or process planned.The Syncrude surface mine, producing a total of 675 000 tonnes of ore and waste per day, rates as one of the largest mines in the world. A strip mining method is utilized, with two or three operating benches necessary to excavate a total depth varying between 60 m and 70 m. The 20 m to 30 m of overburden is removed by electric and hydraulic shovels and 200-ton haul trucks, and dumped in the mined-out pit for final storage. The overburden operation creates a flat bench near the top of the ore zone on which the four 60 m3 draglines operate. The draglines excavate interbanded ore and waste in the highwall, with ore placed on the operating bench in windrows, and waste returned to the mined-out pit. The windrowed ore is reclaimed by four bucketwheel reclaimers, and discharged onto a conveyor system for transfer to the extraction plant."

Jan 1, 1993

By A. G. Roach

HISTORY AND LOCATION SEAL HARBOR GOLD MINES, LIMITED, was incorporated in January, 1934, to take over 116 acres of mining lands in the Stormont gold district, Guysboro county, Nova Scotia. The nearby ten-stamp Mulgrave mill was also purchased, and since that time 974 acres of adjoining properties have been secured from the Government by direct lease. The property is served by a motor road and is about two miles from the village of Goldboro, situated on the shore of Isaac's harbour. The bulk of ?the supplies are brought in by coastal steamer from Halifax, a distance of about 100 miles, since the nearest railway connections are at Antigonish, some 40 miles distant. EARLYY WORK The Seal Harbor properties include the old Partington and Beaver Hat mines. A small tonnage of ore was mined from each and treated on the properties in stamp mills, which were later torn. down . A survey of old records shows that this ore averaged about $8.00 gold per ton. Development work by the present Company was confined to the 100-foot level until February, 1935, but after that rime the incline shaft was deepened to 425 feet and the 300-foot level was explored east and west of the shaft. Six belts of ore were intersected to the west of the shaft. The ore from these belts was hand sorted and the ore portion was put through the 10-stamp Mulgrave mill to defray operating expenses and to serve as a sample of the deposits. The average recovery per ton from this sorted ore was $6.10. Samples of the ore were sent to the testing laboratories of the Mines Branch, at Ottawa, and of Canadian Industries, Limited, at Toronto. Recommendations from both of these authorities were for removal of the coarse gold by concentration and barrel amalgamation, followed by cyanidation of the residue.

Jan 1, 1937

By R. S. Douglas

Introduction During the past few years, a number of changes in the mine operations at Copper Mountain have taken place. The modernization and mechanization were necessitated and given impetus by wartime and other conditions, which were: (1) The urgent need for copper for wartime purposes. (2) The scarcity of skilled labour for underground work. (3) The increase in labour and supplies cost. (4) The necessity of finding ways and means of increasing the output per man-shift, because of the scarcity of skilled labour and the rising cost of labour. (5) The desire to increase safety measures, reduce the silicosis hazard, and aid mine ventilation. (6) The desire to improve the general working conditions in the mine for all workmen. (7) The desire to reduce the amount of dilution in the ore stream by a more selective yet highly productive method of mining. To this end, mining with diamond drills, and transferring broken ore with slusher hoists, appeared to be the answer to the problem. After considerable discussion and estimation of costs for comparison with those of the operation as carried on at that time, the proposed methods were tried out and, in practice, gave very gratifying results. Reference at this point is made to the paper written by C. H. Brehaut, W. N. Taylor, H. A. Shannon, and R. S. Douglas, which was published in the September, 1945, issue of Mining Technology, by the American Institute of Mining and Metallurgical Engineers, Inc., and subsequently in commercial mining journals. Since that time some improvements have been made in undercutting an orebody - the first through experiment and practice, the second through making use of the earth's barodynamic or gravitational forces. It is the purpose of this paper to describe and discuss these later developments.

Jan 1, 1947

By Peter A. Hacquebard

"The coals of the Sydney and Pictou coalfields are generally classed as high volatile ""A "" and medium volatile bituminous coals but there are significant differences within and even beyond this rank. These are related to the observation that the coalification in eastern Canada is essentially post-deformational, resulting in a general increase of rank with depth in individual seams.Exploration drilling in the Sydney coalfield has shown that the rank increases offshore to M. V. bituminous at mineable depths and in the Pictou field to L. V. bituminous coal. There is also a marked easterly shift in rank within one seam at the same depth at Sydney, with the result that M. V. coal will be reached sooner in the Donkin Reserve area (at 700 m depth) than in the Lingan-No , 26 Reserve area (at 900 m depth). These rank changes are important for the manufacturing of metallurgical coke as shown with coke stability predictions based on petrographic analyses. The L. V. coal of the Pictou field can be used for blending purposes and is the only known L. V. deposit of mineable thickness in eastern Canada.In addition, the vertical rank changes between seams have been studied in ten boreholes. They are not constant within the confines of the Sydney coalfield. Four separate areas can be recognized, each with different coalification gradients, which can be related to changes in the paleogeothermal gradients . Variations of 2.5 degrees to 6. 7 degrees CI IOO m are indicated and geological causes for these changes are suggested.IntroductionThe Sydney coalfield is the largest and most important field in eastern Can ad a, and although it has been in production some 200 years, the remaining ""demonstrated "" resources of 1.6 billion metric tons can extend its production capability for at least another 100 years. All coals mined are high volatile "" A"" bituminous and have been used for both thermal and metallurgical purposes. For the latter rank variations even of a minor scale are of critical importance for the manufacturing of metallurgical coke.The significance at the present time of the Pictou coalfield, which has only modest remaining "" demonstrated"" resources of 60 million metric ton s, lies in the discovery in 1975 of a 14-million-ton deposit of low volatile bituminous coal. It is the only known low-volatile coal in eastern Canada and is suitable for use as a blend for metallurgical coal. As such, it could supply the Sydney coke ovens for a period of 30 years at the current rate o f coke production and replace imported American low volatile coal.Consequently, coal rank studies of the Sydney and Pictou fields are important not only from a geological point of view, but also because of economic considerations."

Jan 1, 1984

By R. Bashir, J. F. Hatley

ABSTRACT Northern Saskatchewan boasts some of the world’s largest known high-grade uranium deposits. The successful mining of these deposits cannot be accomplished without overcoming technical challenges, however, which include high grade of the uranium ore, specialized mining methods to deal with groundwater at high pressures, and poor ground conditions. This paper discusses the various mechanisms of inflows at three of Cameco Corporation’s sites in northern Saskatchewan. The risk of inflows is quantified in terms of unique challenges due to hydrogeological conditions, rock mass integrity, and uncertainty in geological conditions. Strategies in the case of an inflow are also briefly described.

Jan 1, 2013

By K. Winterton, Carruthers. J.

"Attempts have been made to produce hardened structures of a pseudomorphic type in various carbon and alloy steels. In order to obtain martensite with a fine distribution of cementite, an initial structure of fine lamellar or nodular pearlite is required; this may be obtained by conventional means. This is followed by partial austenitization and quenching.Two methods have been tried to induce partial austenitization:(a) A resistance (direct current) heating method involving rapid entry into the austenite field.(b) A new method, described as the ""threshold"" technique, involving homogenization of temperature just below A 1, followed by entry into the austenite field; two furnaces are required.The resulting structures have been examined for microstructures, hardness, tensile, and impact values. The tensile properties are comparable with those obtainable by conventional treatment methods. Impact values are disappointing, but this is explainable from the nature of the manifold changes occurring."

Jan 1, 1960

By Nirmal Weerasekara, Lian X. Liu, The University of Queensland, Weiguo Xie, Benjamin Bonfils, Ping Yu

A mill model structure based on the population mass balance framework incorporating breakage characteristics, slurry and solids transport, product classification and discharge and energy consumption was reported in XXVII IMPC and named the Generic Tumbling Mill Model Structure Version I (GTMMS I). In this work, a new 4D (four dimensional) appearance function sub-model based on the experimental results of the JK Rotary Breakage Tester (JK RBT) was developed to describe the breakage characteristics and was applied to this new model structure. The newly developed 4D appearance function model has fewer fitting parameters and is more generic in nature. Most importantly, it is applicable to both high and low energy impact breakage. It is therefore much more versatile in comparison to the existing JKMRC t10- tn appearance function and the size-dependent JK M-p-q t10-tn appearance function. In addition, the Discrete Element Method (DEM) energy distribution model was integrated into the new model structure. With DEM results providing energy distribution information inside the mill directly, the selection function and the back-calculation method used in the existing JKSimMet modelling method are not needed in this model structure. With the above two revolutionary innovations, the previous model structure was upgraded to the Generic Tumbling Mill Model Structure Version II (GTMMS II). Furthermore, the new model structure is dynamic in nature with time-stepping technique for non-steady-state simulation. A case of the dynamic grinding of a SAG mill was studied to validate the GTMMS II. The model simulation results agreed well with the plant data. With the newly developed 4D appearance function model, the incorporation of DEM energy distribution and transport function, the GTMMS II is an important step forward towards mechanistic modelling of tumbling mills.

Jan 1, 2016

By \/eena Sahajwalla, Jonathan Dicker, Paul O'Kane, Cath Skidmore, James Dankwah, Magdalena Zaharia, Rita Khanna, David Knights, N Saha-Chaudhury, Somyote Kongkarat

Due to the inherent limitations of current methods of disposal of end of life polymeric materials, avenues are researched towards developing alternative, environmentally friendly and economic recycling processes. Different polymeric materials (i.e. rubber, high density polyethylene (HDPE) and polyethylene therephtalate (PET)), quite distinct in terms of chemical structure and composition, were considered in the present study as carbon resources in EAF steelmaking. Investigations were conducted in both laboratory and industrial scale steelmaking to assess the effectiveness of using these materials as carbon sources for slag foaming in EAF steelmaking. Slag foaming is important because it enhances furnace efficiency.

Jan 1, 2011

By David Sanscartier, Elizaveta Petelina, Alexey Klyashtorin

This paper provides an overview of the radiological risk mitigation approach applied by the Saskatchewan Research Council (SRC) for the remediation of 35 legacy uranium mine sites in northern Saskatchewan where uranium exploration and extraction took place in the 1950–60s. Mining activities resulted in an irregular increase of the gamma radiation dose rate (up to 18 μSv/h). The radiological objectives for the sites include a gamma dose rate at a spot (<2.5 μSv/h above local background), and the dose rate averaged over a hectare (<1 μSv/h above local background). These objectives are generally achievable at the impacted sites through the installation of shielding soil cover. This method may be impractical for site areas with rough terrain (e.g., steep slopes) and/or difficult access. A risk assessment approach is applied to determine if these areas can be safely left uncovered or if additional mitigation measures should be implemented. The risk assessment approach is based on two factors: (i) the ambient radiation dose rates collected through gamma surveys, and (ii) actual land use data collected through various surveys of activities of local community members at the sites. Exposure scenarios based on four land uses are applied to estimate a potential annual dose load for members of the public. The estimated doses are compared with the criterion of 0.3 mSv/a recommended by the Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM). If the criteria are not satisfied, a mitigation plan is developed, and post-remediation gamma levels are modelled using GIS tools to evaluate the performance of the proposed mitigations. The proposed approach allows the team to optimize resources for the site remediation so that public exposure to NORM are as low as reasonably achievable after remediation.

Jan 1, 2020

By S. Shairp

"After cooling and thickening, slurry from the second stage of the Hudbay zinc pressure leach circuit is filtered and washed on a belt filter prior to disposal. At times, the belt filter can be a bottleneck to the process. Preliminary studies show that filterability of the second-stage (HAL) autoclave leach residue can be indicated by particle size distribution of the filter feed and filtered residue cake. In particular, the Volume Weighted Mean Diameter, D[4,3], generated by a laser diffraction particle size analyzer from samples of HAL Filter feed, shows residues that filter more poorly have a lower Volume Weighted Mean Diameter than those that filter better. INTRODUCTIONHudbay produces cast zinc metal from blends of zinc concentrates at its metallurgical complex in Flin Flon, Manitoba, Canada, using Sherritt’s two-stage pressure leach process (Collins et al., 1994; Collins et al., 1995; Barth et al., 1998; Shairp et al., 2006). Pressure leaching replaced the original roastleach- electrowinning process in 1993.Filtration for the second-stage (HAL) leach residue originally consisted of two stages of vacuum drum filtration with intermediate cake repulping stirred tanks. As part of Hudbay’s 777 Project, with a designed increase in cast zinc production, a pre-feasibility study by SNC-Lavalin Inc. showed that losses of soluble zinc in the zinc pressure leach residue could be reduced by installing more efficient filtering and washing equipment. Based on laboratory performance, capital cost, installation ability, and potential operating cost savings, a 70 m2 Filtres Phillipe belt filter was chosen for the HAL residue, and commissioned in 2000/2001.When the HAL belt filter is performing well, there is no pooling of water on the surface, moisture content is relatively low, and subsequent analysis shows that water soluble zinc content is relatively low. There have been occasions where the filter has performed poorly with respect to the aforementioned parameters. Aside from the filter experiencing mechanical difficulties, there are several variables affecting leach residue filtration:"

Jan 1, 2012

By A. E. Wraith, R. Harris, J. Qiu, R. Parra

Small pilot scale experiments have shown that it is possible to almost fully eliminate the minor elements (ME), namely As, Sb, Bi and Pb contained in smelter dusts by vacuum calcination of mixtures of the dust with sulphidizing agents such as dirty copper concentrate or elemental sulphur at 900 °C and 80 +/- 30 Pa for 90 minutes. The products of this calcination are a residue comprising a purified mixture of copper containing compounds along with the gangue constituents and a high sulphur condensate comprising a mixture of the minor element compounds. In particular, the Cu:ME ratios of the concentrate and dust were increased from 250 and 50, from 28 and 12 and from 36 and 8 to roughly 3000, 3000 and 100 for the calcine, for Bi, As and Sb, respectively. It has also been calculated that (i) the copper content of the vacuum calcine may be recovered by feeding it into a Peirce-Smith converter during its slag blow, and (ii) the resulting recycling could increase the minor element treatment capacity of a smelter by 100 % while also reducing the blister As content by a factor of three. The experimental results are briefly discussed and a treated dust recycling option is examined. Example operating conditions are presented and available commercial technology for the vacuum calcination of the mixtures is reviewed.

Jan 1, 2007

Why A Friction Hoist? B EFORE discussing the equipment, it would be instructive to review the factors that influenced the management of Opemiska Cop-per Mines to purchase a friction hoist rather than a conventional double drum hoist. The mine required that 250 tons per hour be hoisted from a depth of 2,100 feet. They also specified that the top speed should not exceed 1800 feet per minute. Eight ton capacity skips in balance and a maxi-mum hoisting speed of 1725 feet per minute would meet the required <Output on a duty cycle as follows: Loading time Creep away from loading pocket Accelerate (at 2.5 ft/sec2) 10 seconds 5 seconds 11.5 seconds Full speed run Decelerate (at 2.5 ft/sec2) Creep into dump Cycle time Trips per hour Tons per hour 72 seconds 11.5 seconds 5 seconds 115 seconds 31 31x8 = 248

Jan 1, 1962

By G. H. McKay

AT the Eagle mine, near Gilman, Colorado, where the Empire Zinc Company have installed an underground mill, transportation problems were comparatively simple. A railway siding on the Denver and Rio Grande railway is equipped with an unloading dock or platform at the portal of their service incline adit to the mill. This 18-degree incline is approximately 600 feet long from the unloading track to the head of the mill skipway. For the Big Missouri mill, upwards of 2,500 tons of material and equipment had to be trucked from tidewater at Stewart, B.C., a distance of 21 miles to the Big Missouri camp at elevation 2,800. From that point, this freight had to be moved either over or through the Big Missouri ridge, rising to elevation 3,450, to its final location 800 feet from the surface between elevations 2,150 and 2,350. Immediately after leaving the government dock at Stewart, the road crosses the International boundary line into Hyder, Alaska, and then follows a water grade for eleven miles along the lower stretches of the Salmon river. leaving the river, the road climbs for two miles before crossing back into British Columbia territory at Silver Heights, and then continues for another mile and a half to where the Big Missouri road branches off from the main road to the Premier mine. For a distance of four miles from the junction of the roads, the Missouri road is very narrow, with many sharp curves and with irregular up and down pitches and grades up to 25 per cent until it reaches the Summit. From there on, a fairly easy grade leads a mile and a half to the end of the road on Joker Plats. In winter, the last stretch of road is subject to heavy snow drifting, especially through a narrow funnel-shaped gulch, known as &apos;The Gap&apos;, where the snow may pile up to a depth of over twenty feet.

Jan 1, 1938

By J. Peck, F. Brackebusch, M. Scobie

"A number of alternative strategies exist to improve narrow orebody stope productivity and safety through mechanization. Particular attention is given to one of these: the development of an in-stope mining machine. This paper summarizes those characteristics of vein orebodies in Canadian mines which are considered to govern such mining machine design. It then reviews past and current attempts to develop hardrock mining machines which could potentially be applicable to narrow stope widths.IntroductionSerious interest is mounting to exploit new technology in the development of methods and machinery to stope narrow, hardrock, orebodies. The motives relate not only to the foreseen need to maintain or reduce production costs, but also to considerations of manpower availability, safety, ground control, ore recovery and dilution. This also follows the demonstrated success of technology application in larger metal orebody stoping, where machine development has been seen to lead to improved productivity as well as the future prospects of continuous mining systems and eventual automation, e.g. ITH blasthole drill development and bulk mining. This paper deals in particular with machine design for ore fragmentation in narrow, hardrock orebodies. It is considered that such machine design closely interacts with the over-all stoping method design and that both require consideration in parallel to ensure success in mechanization."

Jan 1, 1990

McArthur River Operation is the world?s largest high grade uranium deposit and is located in Northern Saskatchewan. McArthur River came into production in December 1999 with a number of innovative technologies to allow for mining of a high grade uranium deposit in challenging geotechnical and hydrological conditions. The raisebore mining method has been supplemented by the continued development of a boxhole mining technique to allow for mining of mineralization that cannot be accessed with a drill chamber from above. An innovative freeze wall re-design ? a cathedral freeze wall, was implemented in 2009 to allow for top access of a new orebody in the unconformity area of the Athabasca Sandstone. This paper highlights some of the ongoing improvements to the mining method and the innovative risk mitigation applied to manage the extraction of this challenging orebody.

May 1, 2011

By Fathi Habashi, Michel Pagé, Farouk T. Awadalla

"Chrysotile asbestos can be dyed with certain dyestuffs to form stable coloured products whose hemolytic and cytotoxicity are greatly reduced. Examples of these dyes are Thiazol Yellow G (a monazo dye) and Trypan Blue (a diazo dye). Other dye stuffs, for example, basic dyes with triphenyl methane structure, Brilliant Yellow (a diazo dye), and Methylene Blue (a thiazine dye) colour asbestos but do not reduce its toxicity. Similarly alizarin, 8-hydroxyquinoline, and representative members of the phthalein group Bromocresol Purple and Phenolphthalein.IntroductionThere is, at present, a controversy regarding the dangers of asbestos fibres, and attempts are being made to render it less toxic. One of these attempts consisted of treating chrysotile asbestos with gaseous phosphorus oxychloride, POCI], at ambient temperature and in absence of moisture. The product had to be heated at 300°C to 500°C to expel exess entrained reagent to get a material containing 0.5070 to 5% phosphate groups and known as Chrysophosphate (Lalancette and Dunnigan, 1982). This product showed decreased toxicity as measured by its hemolytic effect on red blood cells (fable 1). In another approach, Flowers (1983) showed that when chrysotile asbestos was thoroughly mixed with a solution of ferric ammonium sulphate and the slurry was then filtered and dried, the product showed a marked decrease in cytotoxicity.In the present investigation the problem of toxicity was considered from a different point-of-view. Chrysotile asbestos is a hydrated magnesium silicate that can be represented by the structural model shown in Figure 1 from which it can be seen that magnesium hydroxide groups, Mg(OH)2, form a part of the silicate structure. Certain organic reagents that are known to react with magnesium ion in solution to form chelates were reacted with asbestos to find out whether a chelate was also formed on the fibres, and if so , what will be the hemolytic action and cytotoxicity of the product."

Jan 1, 1991