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By R. Augsten, K. K. Feng, K. C. Cheng

"Methane emission and the desorption characteristics of vertical borehole coal samples of Greenhills multiple seams in the vicinity of Elkford, British Columbia were investigated. Three vertical boreholes at depths of 335 m, 380 m and 395 m were drilled along the west wall of an active open pit mine and 44 core samples from various coal seams were obtained for desorption studies.The results are presented in three tables and illustrated with six figures. The methane content was found to increase significantly at depths greater than 200 m. The adsorption equation by Kim and the properties of the coal have been used to predict the methane content and these were compared with the measured values by the direct method.IntroductionThe coalification of plant material in the sedimentary rock produces different ranks of co al and gases of various composition. The gas mixtures are retained in coal beds and rock strata under pressure. The gas content in a coal bed varies considerably depending on the rank of coal and the depth of overburden. The gas content is defined as the volume of gases adsorbed in a unit weight of coal materials. The net amount of gases remaining in a coal seam depends on the difference in the rate of generation of methane by geo-thermal heat and the rate of diffusion of the gases out of the coal bed through sedimentary cover. The major factor that causes the change in rank and the liberation of gases is the temperature, which is governed by the thermal conductivity of sedimentary cover and the heat flux through the underlying rocks. The rate of diffusion of the gases out of the coal is governed by the porosity of the overlying rocks and the degree of fracture. The measured values of gas content in major North American coal beds are from zero up to 24 cm3 per gram of coal(1,2). A gas content of 2.5 to 9 cm3/g is considered ""gassy"" and that of 9 cm3/g or higher is considered ""very gassy"" for underground mining(3). Normally, the gas mixtures released from bituminous coal in Canada contain 90 to 98% methane and the remainder is made up of CO2, N2, 02, H2, He and other hydrocarbons(4)."

Jan 1, 1984

By G. P. Demopoulos

"The recovery and separation of platinum-group metals (PGM) from primary and secondary materials currently attracts a lot of interest due to the high value of the metals and their increasing demand for high-tech applications. Thus, the traditional refining processes are gradually replaced by newer more efficient separation techniques such as solvent extraction and ion exchange. In this paper the classical and modern refining techniques are reviewed and the pertinent solution chemistry dictating proper processing strategies in each case is discussed. The technological advantages of the modern separation methods are emphasized and reference to the recovery of PGM from primary as well as secondary materials is given. INTRODUCTIONDue to their outstanding physicochemical properties, such as catalytic activity, conductivity and corrosion/oxidation resistance, precious metals now find extensive usage outside of the traditional jewellery and investment industries. The increasing use of precious metals in such areas as electronics and catalysis, as well as their increasing high value, has led to a growing interest in their recovery and separation from primary and secondary materials.Quantitatively the demand of platinum metals in the western world by area of application is described in Table I. Platinum and palladium represent 90% of the total demand, Rh and Ru 8% and the remaining is taken by Ir and Os. In terms of value the following were the average prices (US$/oz) of the metals in the second half of 1986: 500 Pt, 125 Pd, 1200 Rh, 650 Os, 400 Ir and 80 Ru. Due to these prices, exploration, mining, reclamation and refining activity were very high in South Africa, the biggest producer of Pt metals in the world, as well as in other areas: United States (Stilwater deposit), Canada (Sudbury, Marathon and Lac des Isles, Ontario; Kenly Lake, Quebec, etc.), Australia, Europe and elsewhere"

Jan 1, 1989

By J. C. Kurnia

Presence of fine dust in air causes serious health hazard for mine operators resulting in such serious problems as coal workers? pneumoconiosis and silicosis. Major sources of dust appear of course along the mining face where the minerals are extracted. Proper control and management are required to ensure safe working environment in the mine. Presented here is the use of a computational fluid dynamic (CFD) approach to investigate the flow and dust behaviour in mining tunnels. The objective of this study is to propose and examine various strategies to mitigate dust dispersion from the mining face and reduce dust concentration to a safe level for the operator. In a companion study, the authors investigated various methods for mitigating dust dispersion from the mining face to ensure safe dust concentration levels in the mine tunnel. Among the examined methods, implementation of brattice to direct the flow from the main airway to the mining face is the most effective method to disperse dust particles away from the mining face. The installation of brattice, however, will limit the movement of mine operators and vehicles in the tunnel. Hence, application of a hybrid brattice which is a combination of a physical brattice along with suitable directed and located air curtains is proposed and examined. Based on the CFD simulation results, over a range of parameters of interest, it was found that the physical brattice blocks the ventilation air and directs it to the mine face while an air curtain located along the brattice outlet offers flexibility in keeping the dust away from the operator allowing more freedom for the operator and the equipment. Results of the modelling over a range of parameters of interest are presented and discussed with the goal of managing dust concentrations within safe limits for the operator.

Aug 1, 2013

By D. F. Hambley

"In designing are passes f or underground mines specific consideration should be given to unimpaired flow of broken rock, the dump point, and typical practices f or overcoming operational difficulties. Design features such as branches, bends, and knuckles should also be considered. This paper pro vides engineering information and various criteria for designing are passes, draw points. feeders, and support systems, together with several illustrative examples.IntroductionOre passes are the primary mean s o f vertical transfer of mined ore to the ore bins and loading pocket from which the o re is hoisted to the surface (Fig. 1) . While the words "" ore"" and ""ore pass"" are used here, such transfer systems ca n be used for any broken rock.The most extensive ore pass systems are found in caving and sublevel stoping mines. Extensive ore pass systems are also found in multilevel mines having steeply dipping orebodies. In more flat-lying orebodies , ore pass systems are sometimes used in conjunction with conveyor systems .Two decades have passed since the principles of the flow of bulk solids were formulated (Jenike, 1961, 1964; Johanson and Colijn, 1964; Kvapil , 1965). However, few published papers are available that discuss the design criteria for ore pass systems. Therefore, the aim of this paper is to provide the information necessary for good o re pass design .Rock Flow in Ore Pass SystemsIf an ore pass system is to fulfill its function, the transfer o f material must occur in an orderly fashion and in such a way that the full size of the opening is employed effectively. Apart from un controlled flow at the drawpoint, or outlet , whose design will be considered later in this paper, two occurrences may impede flow in an ore pass, namely:• Hangups due to interlocking arches.• Hangups due to cohesive arches.Prevention of each of these problems will be discussed in succeeding sections of this paper. A third problem piping, is related to the ratio of the drawpoint size to the o re pass size and will be discussed under drawpoint de sign."

Jan 1, 1987

By J. P. Grieco, F. W. Grieco

"Manufacturing of Jaw CrushersOriginIn 1858 Eli Whitney Blake invented the first successful mechanical rock breaker-the Blake-type jaw crusher. Blake adapted a mechanical principal, the powerful toggle linkage system used to transform rotating motion and energy into oscillating mot ion and tremendous compressive forces. Today these same principals apply and the basic Blake-type jaw crusher is one of the leading machines of its class for heavy duty primary crushing service.In 1881 Philetus W. Gates patented a design for a crusher, the forerunner of the modern gyratory crusher which dominated the field from the late 1800s to the early 1900s. In 1910 the largest gyratory crushers built had 48-inch openings. However, about this time the jaw crusher came to life when the Power and Mining Machinery Co. built an even larger sized opening crusher-a giant 84-inch by 60-inch jaw crusher for a trap rock quarry in Pennsylvania. A 24-inch gyratory crusher became the ideal sized secondary machine for this size jaw. From that time on jaw crushers were looked on favourably as primary breakers and lines were brought up to date to parallel the already developed gyratory lines.FunctionMost heavy duty Blake-type jaw crushers work basically the same way. They are ruggedly designed and capable of crushing material in some cases in excess of 80, 000 p.s.i. compressive strength. They are very simple machines with few moving part s and, with the exception of replacement of renewable parts, are relatively maintenance free. It is quite common to have these machines in product ion for 20 to 30 years. The following will de scribe how these machines work. Large-diameter high-inertia flywheels which are connected to the main eccentric shaft, rotate inside a connecting rod type mechanism called a Pitman. It transforms rotating motion into vertical oscillating motion. This vertical motion is in turn transformed into reciprocating mot ion by means of a system of 2 toggles, each connected to the Pitman. The rear toggle is connected to the fixed rear head, and the front toggle is connected to the swing jaw which is hinged at the top of the crusher. With each rotation of the eccentric shaft the swing jaw opens and closes on rock which is fed into the crusher chamber, crushing the rock in a series of bites. These bites, or strokes as the y are called, usually vary between 1/2 inch to 1 1/2 inch at speeds of 120 to 200 strokes per minute. The reduction ratio of feed input to discharge is usually about 8 to I. Output capacities can vary from 100 tons/hour to 1200 tons/hour depending on the size of machine and its discharge opening. Horsepower requirements can vary from 75 hp to 400 hp.The entire crusher chamber is lined with replaceable 14070 manganese steel liner plates. This material is ideally suited for the job since it hardens as it wears during crusher operation. Manganese is also used in the high wear areas at each end of the toggle plates."

Jan 1, 1985

By J. P. Grieco, F. W. Grieco

"Manufacturing of Jaw CrushersOriginIn 1858 Eli Whitney Blake invented the first successful mechanical rock breaker-the Blake-type jaw crusher. Blake adapted a mechanical principal, the powerful toggle linkage system used to transform rotating motion and energy into oscillating mot ion and tremendous compressive forces. Today these same principals apply and the basic Blake-type jaw crusher is one of the leading machines of its class for heavy duty primary crushing service.In 1881 Philetus W. Gates patented a design for a crusher, the forerunner of the modern gyratory crusher which dominated the field from the late 1800s to the early 1900s. In 1910 the largest gyratory crushers built had 48-inch openings. However, about this time the jaw crusher came to life when the Power and Mining Machinery Co. built an even larger sized opening crusher-a giant 84-inch by 60-inch jaw crusher for a trap rock quarry in Pennsylvania. A 24-inch gyratory crusher became the ideal sized secondary machine for this size jaw. From that time on jaw crushers were looked on favourably as primary breakers and lines were brought up to date to parallel the already developed gyratory lines.FunctionMost heavy duty Blake-type jaw crushers work basically the same way. They are ruggedly designed and capable of crushing material in some cases in excess of 80, 000 p.s.i. compressive strength. They are very simple machines with few moving part s and, with the exception of replacement of renewable parts, are relatively maintenance free. It is quite common to have these machines in product ion for 20 to 30 years. The following will de scribe how these machines work. Large-diameter high-inertia flywheels which are connected to the main eccentric shaft, rotate inside a connecting rod type mechanism called a Pitman. It transforms rotating motion into vertical oscillating motion. This vertical motion is in turn transformed into reciprocating mot ion by means of a system of 2 toggles, each connected to the Pitman. The rear toggle is connected to the fixed rear head, and the front toggle is connected to the swing jaw which is hinged at the top of the crusher. With each rotation of the eccentric shaft the swing jaw opens and closes on rock which is fed into the crusher chamber, crushing the rock in a series of bites. These bites, or strokes as the y are called, usually vary between 1/2 inch to 1 1/2 inch at speeds of 120 to 200 strokes per minute. The reduction ratio of feed input to discharge is usually about 8 to I. Output capacities can vary from 100 tons/hour to 1200 tons/hour depending on the size of machine and its discharge opening. Horsepower requirements can vary from 75 hp to 400 hp.The entire crusher chamber is lined with replaceable 14070 manganese steel liner plates. This material is ideally suited for the job since it hardens as it wears during crusher operation. Manganese is also used in the high wear areas at each end of the toggle plates."

Jan 1, 1985

By T. Holmes, S. Davison

"The Special Standard Surge bin at Agrium’s Vanscoy Potash Operations (VPO) has been plagued with flow problems and wear, and corrosion issues for it’s entire working life. Investigation showed that the carbon steel construction, bin geometry, and resultant funnel-flow pattern were directly responsible for production losses and disproportionate maintenance and capital costs. Potash enters this bin at between 140°C and 165°C, but the stagnant potash outside the active flow channel was much cooler, allowing moisture to migrate toward the outer regions, which caused corrosion of the walls and reduced live capacity as the potash in this area hardened and built up on the walls over time.A 2013 inspection revealed holes and paper-thin areas in the lower cylinder wall sections and in the conical hopper. The only thing preventing major leaks and even a potentially catastrophic failure was the buildup of stagnant hardened product on the cone walls. It was concluded that the cone had reached the end of its life and required replacement. VPO’s original plan was to replace the cone in kind and repair the cylinder as necessary; however, a failure-mode and bin-performance investigation combined with a lifecycle- cost analysis indicated it would be better to redesign the hopper.For success in retrofit projects, it is essential at the design stage to consider the bulk solid flow properties and the operating environment involved. Because education in this area is not offered at a university level, engineers often do not fully appreciate the effects of the flow properties of bulk solids on bulk material handling equipment.Jenike & Johanson conducted flow properties tests on samples of potash and using the data, redesigned the bin and the feeder. After the modifications, VPO’s surge bin provides safer, more reliable operation with a much longer predicted working life. Using this retrofit as an example, we aim to provide a general understanding of bulk solids flow theory and highlight the importance of customizing the design to the appropriate flow properties in the cost effectiveness, reliability, and safety of a bulk material handling system."

Jan 1, 2016

The North Saskatchewan River flows southwest to northeast through a 22-km-long valley in the City of Edmonton, supplying the drinking water to dozens of downstream communities. During heavy rains, combined sewers occasionally overflow into the river, which has a significant negative impact on the water quality and the sensitive environment. The West Edmonton Sanitary Sewer (WESS) W12, a syphon connecting the Rat Creek Trunk to the Gold Bar Wastewater Treatment Plant across the river, was designed and constructed to take the overflow to the wastewater treatment plant. Due to the complexity of the project, various 3D technologies were applied to facilitate decision-making processes. 3D models were developed for design review and design conflict detection, while 4D models were established to help create a robust construction schedule. Construction sequencing animation was used to convey design intents and demonstrate construction stages to contractors and workers. The combined applications of 3D technologies helped the project team to identify critical issues, and assured effective communication among engineers, management, contractors, and other parties. Therefore, it provided more opportunities for the success of the project.

Aug 1, 2013

By L. Tapia

The main disturbance for stability in primary grinding using SAG mills is related to continuous changes in the ore being fed to the plant, such as size and hardness. Searching for stability is the first step to accomplish, before trying to maximize the mill throughput. The time variability in the characteristics of the ore being fed from the mine to the plant must be known or inferred to perform adaptive changes in the grinding process control. In day to day operation, such information is not available in real time. Transport times and inventories between the mine and the plant complicate the situation. Under this scenario, Minera Los Pelambres implemented a grinding optimization strategy, based on the real time analysis of certain process variables, such as ore size, mill current consumption, pebble generation and throughput. As a result, both grindability and stability indexes are inferred. This is equivalent to inferring the ore characteristics by knowing its effect on the grinding behavior. These two indexes permit control of the SAG mill total charge level and hence, allow optimization of throughput by means of an expert control system.

Jan 1, 2007

By J. Bensabat, B. Figueiredo, A. Niemi, J. Rutqvist, C. F. Tsang

"A hydro-mechanical model was developed to study the interaction between mechanical deformation and fluid flow in the fault zones during CO2 injection and storage at the Heletz site which was chosen as a test site for CO2 injection experiments in the framework of the EU-MUSTANG project. The potential reservoir for CO2 storage at the Heletz site consists of three sand layers separated by lowpermeability shale layers. The potential consequences caused by fault reactivation, focusing on the shortterm integrity of CO2 storage, are evaluated. The difference in the results obtained by considering the three-layer as an equivalent layer storage formation is analyzed.INTRODUCTIONLarge-scale storage of CO2 in deep underground reservoirs may cause considerable pore-pressure perturbation as well as flux migration and concern has been raised over whether shear slip displacements may be induced in nearby faults, as a consequence of their reactivation. A state-of-the-art review can be found in Rutqvist (2012), which describes the various possible effects resulting from CO2 injection into a deep sedimentary basin, including those involved in reservoir stress–strain changes, micro-seismicity, caprock sealing performance, and potential fault reactivation. Moreover, several studies have recently shown how CO2 injection may produce seismic events both on major faults (i.e., large faults with large initial shear offset) (Cappa & Rutqvist, 2011a, b, 2012), and on minor faults that might have gone undetected during the site characterization, e.g., faults less than 1 km long and without detected initial offset (Mazzoldi et al., 2012).The present paper is concerned with the Heletz formation which was chosen as a test site for CO2 injection experiments in the framework of the EU-MUSTANG project. The Heletz site located at the southern Mediterranean coastal plain of Israel and the structure is an anticline fold with a crest of about 4 km by 2 km. The structure is gently dipping to the east, truncated by a pinch-out line to the west and subdivided into a number of blocks by transversal normal faults with small displacements. The water table is located at 300 m below the land surface. An areal sketch of the site with the elevation of the caprock and the location of the borehole that has been chosen for the CO2 injection experiment is presented in Figure 1."

Jan 1, 2015

By Russell Spry

THE cyanide plant of the Cariboo Gold Quartz Mining Company, Limited, at Wells, B.C:, in the Barkerville section of the Cariboo mining division, was erected during the latter part of 1932 and placed in operation in January, 1933. The initial capacity of the plant was about 50 tons daily. This was increased to 100 tons at the end of 1934 and stepped-up to 150 tons in September, 1935. It is expected that further plant extensions, for milling a total of 200 tons daily, will be required during the early part of 1936. Recent additions to the mill have been so planned as to permit ready expansion to 275 tons daily when underground development warrants the milling of this tonnage. It is the purpose of this paper to outline briefly the steps taken to bring the plant to its present capacity and to comment on possibilities for further plant expansion. The gold in Cariboo Gold Quartz ore occurs as free gold in the quartz and on pyrite surfaces. Some of it is very finely divided, specks l/10,000 inch having been observed microscopically, according to Dr. G. Hanson. In addition to pyrite, which comprises probably 15 to 20 per cent of the mill feed, galena and sphalerite are present, with small amounts of arseno-pyrite and chalcopyrite. Sulphobismuthites-chiviatite, galenobismutite, cosalite, etc.-occur more or less frequently in certain sections of the mine. Following tests on Cariboo ore by the Mines Branch, Department of Mines, at Ottawa, treatment of the ore by straigh t cyanidation was recommended and a 50-ton plant employing continuous counter-current decantation was erected. This plant was built as a pilot mill, the intention being to erect a larger mill after metallurgical treatment had proved successful over an extended period. This original installation, however, has been enlarged and retained as an operating unit, additional equipment being added to it as capacity increases have been required.

Jan 1, 1936

By Eugene Sun, Qiang Xu

This presentation will review current applications of composite materials in aircraft design and discuss the challenges involved in maximizing the potential of the composites in aircraft applications.

Jan 1, 2010

By P. -A. Bosse, J. Robitaille, P. Blatter

The LaRonde ore is a Cu-Zn-Pb ore with gold (3-4 g/t) and silver (60-100 g/t). The precious metals are recovered with copper concentrate, zinc concentrate and cyanidation of zinc tails via Merrill Crowe precipitation. Subsequent to a recent mill expansion, excessive gold was reporting to zinc concentrate with a concurrent decrease in gold to copper concentrate. Owing to the higher return obtained from the metal, the mill endeavors to recover additional gold and silver to the copper concentrate and minimize the placement of precious metals to the zinc concentrate. A gold deportment study showed that the gold occurs mainly as küstelite, with a moderate amount of electrum and a minor amount of native gold. It also showed that various sulfur-based Au-and/or Ag-bearing coatings on liberated küstelite and electrum were the major mineralogical factors that caused gold and silver to report to zinc concentrate. By frequency, such coatings were observed on 70-80% of total liberated gold particles reporting to the zinc concentrate. Based on the gold deportment and the chemistry of the coatings, the collector chemistry was reviewed and a new collector was added into the circuit which resulted in a significant increase in gold and silver recovery to the copper concentrate. The information obtained from the mineralogy confirmed and guided other process optimization. In this paper, the authors will describe the process mineralogy of the LaRonde ores, and in particular, the mineralogical evidence diagnosing the problem. Reference will also be made to the rationale behind how the problem was solved, the results achieved, and future steps in optimization.

Jan 1, 2005

By A. J. Hargraves

"It is difficult to quantify comparatively the gassiness of a property. The most common index to gassiness, cubic feet of gas per ton of coal mined, is very arbitrary and does not take into account the geological setting nor the mining operation. The gassiness of a virgin coal in situ can be assessed, but no method is precise and the most accurate methods involve prolonged field and laboratory experiments. In general, gassiness increases with depth. Whereas 'gas' normally implies methane, other gases such as nitrogen, carbon dioxide, etc. may be present in seam gas also. The inflammability of methane is a problem, particularly the explosibility of a methane-air mixture; also oxygen dilution is involved in high gas concentrations and some gases are poisonous even in low concentrations. Cross measuring into a virgin seam is usually not as troublesome as development in the seam, where narrow openings may require strong ventilation to dilute gases exuding from the face and sides. Total extraction presents problems of gas from the working seam, or from adjacent seams, particularly at the return side, or of gas-laden air from the goaf streaming out or sometimes surging out intermittently, again on the return side. In pillar extraction or longwall retreating special roadways may be required to allow the side-to-side and end-to-end flushing of the goaf which is somewhat inherent in longwall advancing. Layering may occur, particularly where ventilation conditions are not brisk. Outbursts of gas from adjoining seams may be induced by sudden rupture of roof or floor in caving workings. Outbursts of coal and gas from the working seam may occur, mostly in development work, under special environmental circumstances. Gas problems may be reduced or eliminated by predrainage of gas ....:. rarely successful from the working seam - usually undertaken from adjoining seams prior to escape of gas released by caving. The ideal solution - general predrainage of gas to the surface from measures prior to mining - has yet to be accomplished. • In the planning of gassy mines it is possible to make an assessment of gas contained in the seams and to estimate what proportion will be released into the mine air, but emission of gas into mine workings is never steady and at present there is no better planning criterion than experience at the mine next door!"

Jan 1, 1973

By Karl J. C. Harries

This paper looks briefly at some of the agreements and types of royalties that may be met during exploration activities, but does not go into details relating to them. Agreements can either make or break a deal or relationship. A well drafted, comprehensive and fair agreement can create good relations and trust among the parties and will go a long way towards making a deal work. In the best of all worlds the agreement will be put away and not need to be referred to after it has been signed (but it will be there if needed to sort out potential problems). On the other hand, a poorly drafted agreement or one that is inappropriate to the circumstances or unfair to one of the parties can break a deal and end up with the parties facing each other in that expensive, unproductive and time-consuming occupation ? a lawsuit. Accordingly, it is advisable to involve professional advisers with any agreement. The straightforward one may involve no more that a read through whereas the more complex agreement will require considerable involvement. There is, however, one rule for every explorationist to remember: a professional adviser is only an adviser. His responsibility is to make sure that you have the necessary information to make a reasoned decision but the decision is yours, not the adviser?s. It is your deal, you are going to have to live with it, and it is inappropriate for an adviser to introduce new concepts or amend negotiated ones without your specific instructions. Mineral exploration agreements, although basically option, acquisition and joint participation agreements, come in all the shapes and forms, appropriate to give effect to the endless variety of deals negotiated by the ever-active minds of explorationists. You will note the reference to "joint participation agreements" rather than "joint venture agreements". The latter term was purposely avoided because, with the current activity of explorationists from common law jurisdictions in civil law jurisdictions, it has become necessary for the explorationist to become familiar with corporations and shareholders agreements. As most of you are no doubt aware, under the civil law system a joint venture is normally not recognized as a legal entity and, therefore, joint participation in projects is usually by way of corporations.

May 1, 2003

By D. M. Ward

"The uranium deposits upon which the Rabbit Lake project story is based are located at the eastern margin of the Athabasca Basin just west of Wollaston Lake in northern Saskatchewan. This paper provides a general review of the exploration history for the major deposits and the influence of an expanding geological data base, which served to guide the continuing exploration programs.A brief description of each of the deposits is provided in order of their discovery and with emphasis upon their relative geological and mineralogical characteristics.The Rabbit Lake and Eagle Point orebodies are monometallic uranium deposits localized by thrust faults within the Aphebian Wollaston Group. The Cof/ins Bay A-zone, B-zone, and D-zone are polymetaflic U, Ni, As, Co (Au , Ag) deposits located within the Helikian Athabasca Group at its unconformable contact with the underlying Wollaston Group. INTRODUCTIONThis paper demonstrates the importance of applying the accumulated geological knowledge, gained through the exploration, mining, and development process, to the ongoing success of exploration programs. To emphasize this point, the basic geology of each of the major Rabbit Lake area deposits will be presented in chronological order of their discovery and subsequent development. These depos its include Rabbit Lake, Collins Bay A-zone, B-zone, D-zone and Eagle Point. The geological descriptions are based primarily upon the detailed observations of many current and former geologist s employed by both Gulf Minerals Canada Limited and Eldorado Resources Limited. Much of the early historical data was obtained from Dr. E.E.N. Smith, formerly with Eldorado Resources Limited. Regional GeologyThe Rabbit Lake area which includes the Rabbit Lake, Collins Bay A-zone, B-zone, D-zone and Eagle Point deposit s, is located on the eastern edge of the Athabasca Basin close to the western shores of Wollaston Lake (Fig. I). The area is in the Churchill Province of the Canadian Shield within the Wollaston lithostructural domain, at the eastern edge of the Athabasca Group. The uranium deposits occur within both the Wollaston Group metasedimentary assemblage of probable early Aphebian age, and the diagenetic ally altered quartz sandstones and conglomerates of the Athabasca Group of Paleohelikian age. Both units unconformably overlie granitoid gneisses interlayered with metasediments and a graphitic iron formation all believed to be of Archean age. All uranium depo sits in the Rabbit Lake area occur in close proximity to the Paleohelikian - Aphebian or Paleohelikian - Archean unconformity."

Jan 1, 1989

Presentation Overview Corporate Overview Kutcho Project History Exploration Development Permitting Capstone -Pursuit of Value Building a mid-tier copper producer focused in the Americas Two operating copper mines; Cozamin& Mintomines High grade and low cost 2010 forecast: 80-85 million pounds of copper in concentrates Total Cash Costs* of ~US$1.10/lb to US$1.20/lb of payable copper produced Significant by-products of gold, silver, lead & zinc Growth potential Further expansions at existing Cozamin& Mintomines High grade copper development: Kutcho project, BC Investments in Nevada Copper & Silver Wheaton 100% North American assets Low risk ?Canada & Mexico ?Conventional operations

Oct 1, 2010

By M. J. Michaud, M. J. Lavigne

"Abstract - North American Palladium Ltd. operates its Lac des Iles open pit palladium mine 85 km north of the city of Thunder Bay, Ontario. The Roby Zone deposit occurs within the mafic/ultramafic Lac des Iles Intrusive Complex (LDI-IC), which was created by multiple pulses of magma of varying composition within several closely spaced chambers. Chaotic lithological distribution, the presence of magmatic breccias, and the rarity of rhythmic layering suggest a dynamic intrusive environment with disruptive magma pulses. As of December 31, 2001, measured and indicated resources for the 950 m long by 815 m wide Roby Zone deposit totalled 159 Mt grading 1.55 g/t Pd, 0.17 g/t Pt, 0.12 g/t Au, 0.05% Cu, and 0.05% Ni at a palladium cut-off grade of 0.7 g/t. The Roby Zone contains an additional 73 Mt of inferred resources at similar grades.The Roby Zone is dominated by varitextured gabbro containing pipes and pods of breccia, and large blocks (~60 m across) of varying lithology. Mineralization at Lac des Iles occurs as: (1) a PGEand base metal-rich magmatic matrix of breccia (breccia ore); (2) mineralized dikes or sills (gabbronorite in North Roby ore); (3) lower-grade mineralization in varitextured units that are host to the distinctive breccia ore and envelope the North Roby ore; and (4) high-grade mineralization associated with strong silicate alteration exemplified by high-grade ore.The close spatial association of the mineralized breccias with both varitextured units and silicate alteration leads to an interpretation that the energetic magma that created breccia was charged with a dissolved fluid, and that this deuteric fluid exsolved at high temperatures to migrate through crystal mush, enhancing crystallization along its pathways, resulting in variable grain size. This transformation occurred at high temperature and produced sulfide-poor, varitextured gabbro-hosted mineralization exemplified by some of the mineralization in the North Roby Zone, and also found throughout the Roby Zone. The association of hydrous silicate alteration with mineralization can be explained by continuing fluid migration during cooling and continued metal transport. Résumé - North American Palladium Ltd. opère la mine à ciel ouvert de Lac des Iles située à 85 km au nord de Thunder Bay, Ontario. Le gisement Roby Zone est encaissé dans le complexe mafique/ultramafique de Lac des Iles (LDI-IC), lequel représente une intrusion polyphasée créée par plusieurs pulses magmatiques de différente composition à l’intérieur de chambres magmatiques fermés. La distribution chaotique des lithologies, la présence de brèches magmatiques, et la quasi-absence de litage rythmique suggèrent un environnement magmatique dynamique perturbé par l’introduction de nouveau magma. Au 31 décembre 2001, les ressources mesurées et indiquées s’élevaient à 159 millions de tonnes titrant 1,55 g/t Pd, 0,17 g/t Pt, 0,12 g/t Au, 0,05% Cu, et 0,05% Ni, pour une teneur de coupure de 0,7 g/t Pd. De plus, la Roby Zone contient 73 millions de tonnes de ressources inférées à une teneur similaire.La Roby Zone est principalement encaissée dans un gabbro de texture hétérogène (varitextured) caractérisé par des cheminées et des lentilles de brèches et des énormes blocs (environ 60 m de diamètre) de plusieurs lithologies. Au Lac des Iles, la minéralisation en EGP et en métaux de base se retrouve dans la matrice magmatique de brèches (breccia ore), dans des dykes ou des sills minéralisés (gabbronorite dans la zone North Roby ore), comme minerai de basse teneur encaissant le minerai de brèche (breccia ore) et enveloppant la zone North Roby. Du minerai de haute teneur est également associé avec une forte altération en silicates dans la zone high-grade ore.L’étroite association spatiale entre les brèches minéralisées et les unités de texture variée (varitextured) et l’altération en silicate suggère que le magma énergique qui a causé la bréchification était chargé de fluides. Ces fluides deutérique"

Jan 1, 2001

By S. Sakurai

"Gravitational force is an external body force acting on underground structures. It should be noted that gravitational force cannot be replaced with the surface traction vector (Cauchy stress) which is an internal force. This fact should be properly taken into account in a numerical analysis of underground structures, particularly for structures such as vertical shafts, tunnels, and caverns constructed at great depths. It is obvious that the gravitational force must be conserved at all times.In conventional numerical analyses, the initial state of stress of the ground medium is firstly calculated under the gravitational field. This means that the gravitational force is replaced with stress (surface traction vector), and after that only the initial stress is considered in the calculation of the stresses and displacements of the structure. It should be noted that the initial stress is Cauchy stress consisting of a surface traction vector, while the gravitational force is a body force acting on the mass of the materials. This computational approach may be acceptable for elastic problems because the principle of superposition is valid for elastic materials. However, this approach becomes questionable for elasto-plastic materials because there is no guarantee that the principle of superposition is valid for them.Furthermore, another problem exists in elasto-plastic analyses: The stress state in a plastic zone must satisfy a yielding criterion such as that of Mohr-Coulomb. In order to make the stress state satisfy the criterion, an excess stress beyond the yielding criterion should be transferred to an elastic zone existing outside of the plastic zone. This seems to always be possible, because an elastic zone always exists, no matter how large of a plastic zone appears. In some cases, however, the excess stress cannot be transferred to the elastic zone because the gravitational force must be conserved. Therefore, it is obvious that the magnitude of stress around underground structures may become large and surpass the yielding criterion at great depths where a large gravitational force exists.In this paper, it is demonstrated that in a conventional elasto-plastic numerical analysis of a vertical shaft at a great depth, all the stress components around the shaft become very small, even though a large gravitational force exists. This strange result may be due to the fact that the gravitational force is not properly taken into consideration in the numerical analysis."

Jan 1, 2015

By L. Yaun

In underground coal mining operations, gas content in a coal seam is used to assess the risk of coal and gas outbursts. To estimate the gas content, a number of systems have been developed, however issues remain about the rapidness and accuracy of these systems. To address these issues, a new and improved system has been developed that includes a sampling-while-drilling unit for coal sampling, a coal canister, an underground-based portable measurement unit, a surface-based measurement apparatus, and gas content calculation software. The system has been successfully applied in underground coal mines at Huainan, China. This new, rapid and accurate system, its main components and field trials are described in this paper.

Aug 1, 2013