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By Robin Perry, Claude Bazin

"Discrete transfer functions which use the grinding circuit feed tonnage to predict mass flowrates at reagent addition points in a flotation circuit were calibrated using a dynamic grinding/flotation circuit simulator. Predicted mass flow values are multiplied by reagent addition ratios to obtain actual reagent flow. The transfer functions are currently integrated into the distributed control system of Les Mines Selbaie.IntroductionThe development of adequate tools for the control of flotation processes is a continuous challenge. Since the early 1970s there have been numerous publications dealing with practical aspect of control of flotation processes. Most plants use a combination of feedback and feedforward controls to reduce the effect of the following flotation process disturbances (McKee, 1991):• changes in throughput;• changes in feed grade;• changes in particle floatability (size, liberation, surface oxidation ... ); and • deliberate changes of setpoint;Feedforward control manipulates variables such as reagent and/or air flow rate to attenuate the effect of disturbances such as changes of feed rate and mineral content. The feed forward strategy is driven by measurements of these disturbances. Feedback control is used to maintain process variables to targeted set-points of concentrate or tails grades. The feedback control action is driven by deviation from the set-point, caused by a deliberate change of set-point or disturbances.This paper proposes a method to improve feed forward control schemes by the addition of a simple model for solids transportation. The feedforward strategy considered in this paper is the ratio type, in which the manipulated variable is changed according to a predefmed ratio between this variable and the measured disturbance. A typical example is the ratio of the reagent addition to mass flow of ore.The paper reviews the state of the art in feed forward control strategy applied to flotation processes and describes the method used for predicting mass flow rates. The last section shows an application of the method in the Les Mines Selbaie flotation circuit."

Jan 1, 1994

By CH. Liu, H. X. Jiang, X. Xiao

"A study has been conducted to characterize the fatigue life in 7050-T7451 thick plate by the comparison between an experimental alloy and commercial alloy. The fracture origins were specified and their sizes were measured by scanning electron microscope (SEM). Additionally, the size, number density and spatial distribution of porosity in the experimental material and commercial material were characterized and compared, using X-ray Computed Tomography(XCT). The results showed that microporosity was the predominant site for crack nucleation and subsequent failure of the experimental alloy. However, as for the commercial alloy, fatigue cracks were found to originate from constituent particles. The presence of microporosity in 7050-T7451 thick plate reduced fatigue life of an order of magnitude or more compared to the commercial alloy. The relationships between size of origin and fatigue life were proposed. It was showed that the fatigue endurance was reduced when the size of porosity increased.INTRODUCTION 7xxx series aluminum alloys, due to their combination of high strength, high resistance to stress corrosion cracking, and good fracture toughness, are widely used in structural engineering applications where high-strength and low-density characteristics are fundamental design requirements (Williams& Starke, 2003). Every designer is striving to find an optimal combination of properties including strength, corrosion resistance and fatigue resistance (Wanget al., 2016). Based on the design principles of aircraft, a higher fatigue resistance of aluminum alloys are required. Thus, many investigations have been carried out on the microstructures and its effect on fatigue properties of the 7xxx series aluminum alloy (Robson, 2004; Schubbe, 2009).Microporosity, which is a common defect in casting materials, can lead to a significant deterioration of mechanical performance and fatigue resistance, especially in the high alloyed 7xxx aluminum alloys. The actual valid loading area decreases due to microporosity, which results in detrimental effect on the mechanical properties. Many experimental studies have been conducted in this research field. Mayer et al.(2003) investigated the fatigue properties of magnesium alloys produced by high-pressure die-casting. The results show that porosity in magnesium alloys greater than0.18mm diameter may be considered as the most important material defect for high cycle fatigue and fully reversed loading conditions. Nadot et al.(2004) found that the near surface defects are much more dangerous than the internal defects. Wang et al.(2001a) used the Weibull statistics method to analysis the influence of the microporosity, oxides and particles on the A356-T6 alloy fatigue life. The results show that, the porosity is more detrimental to fatigue life than oxide films and particles. With regard to fatigue resistance, although the deleterious effect of microporosity has been generally acknowledged, a quantitative understanding between casting microporosity and fatigue life in 7050-T7451 plate is not well established."

Jan 1, 2018

By W. Hrynewich

"The Central Canada Potash facility, a division of Noranda Metal Industries Limited, is located 3 kilometres south of the junction of Highways 16 and 2, about 75 kilometres south-east of Saskatoon, Saskatchewan. The site occupies 26~ hectares of land and includes well-equipped machine and electrical _shops, a 325,000-tonne muriate storage and reclaim warehouse, a stores warehouse, processing plant (mill), two mine shafts (one for production, the other for servicing and personnel transport), as well as a two track product loading complex. Access to the site is by road and railway (CN and CP Rail). Suppliers of operating and maintenance use both means of transportation, whereas muriate shipments are entirely by railway.Currently five continuous mining machines - one a Goodman 526 borer and four Marietta 911-A units produce some 10,500 tonnes of ore per operating day. A smaller Voest-Alpine Af.1-100 boom type miner is used for floor cutting which was previously done by a production unit. In order to maintain safe, competent ground conditions only 35 percent of the total ore is extracted. At this rate mine reserves are deemed adequate for about 100 years. The plant has operated since August 1969 and has a current practical annual capacity of 1,270,000 tonnes of muriate. As of June 30, 1981, some 11.9 million tonnes of muriate had been produced from 31.4 million tonnes of ore. Of the total muriate, 6.1 million tonnes was granular, 4.8 million was coarse, and 1.0 million was standard. No standard product has been made since August 1978."

Jan 1, 1982

By H. Scott Swinden

"ForewordA symposium on base metal deposits was held in Bathurst, New Brunswick, from June 10-13, 1990, sponsored jointly by the Geological Surveys Branch of the New Brunswick Department of Natural Resources and Energy, the New Brunswick Prospectors and Developers Association, and the Geology Division of the Canadian Institute of Mining, Metallurgy and Petroleum . Papers prepared for the symposuim are being published as a series of articles in the CIM Bulletin. This second paper (the first was by Fyffe, et al., in Vol. 83, No. 938) in the series presents an overview of the paleotectonic settings of massive sulphide deposits in the Dunnage Zone of Newfoundland with emphasis on volcanic geochemistry.ABSTRACTCambrian and Ordovician volcanic sequences of central Newfoundland, which record the history of the Iapetus Ocean, are prolific hosts to volcanogenic massive sulphide (VMS) deposits. Geochemical, isotopic and geochronological studies show that the vestiges of Iapetus in Newfoundland probably record a complex series of island arcs and back-arc basins that were marginal to, rather than part of, the main ocean basin of Iapetus. The geochemical and isotopic data provide a means of characterizing the tectonic environment of individual volcanic sequences, and allow us to identify a number of distinct tectonic environments in which VMS depositiontook place.Four tectonic environments have been identified as being associated with VMS deposition: (I) back-arc environments hosting VMS deposits include both N-MORB-type ophiolites (e.g. Skidder?) and volcanic sequences with oceanic island (or within plate) tholeiite characteristics (e.g. Great Burnt Lake); (2) primitive arc environments include both supra-subduction zone (SSZ) ophiolites (e.g. Betts Cove, Rambler) and volcanic/epiclastic sequences (e.g. Point Leamington, Duck Pond) and are characterized by abundant arc tholeiites, with lesser refractory lavas and rhyolites; (3) mature arc environments comprise dominantly thick felsic and mafic volcanic piles in the Buchans - Robert's Arm Belt (including the Buchans camp) and are characterized by dominantly calc alkalic basalt and andesite; and (4) continental rift environments occur in the Hermitage Flexure area (e.g. Strickland deposit) and are characterized by dominantly felsic volcanic sequences.Island arc environments are by far the most prolific hosts to VMS deposits. Patterns of VMS distribution in central Newfoundland show that similar tectonic settings may be recorded by very different stratigraphic sequences (e.g. both ophiolites and thick volcanic/ epiclastic sequences may record primitive arc rifting) and emphasize the importance of the rifting in VMS generation, irrespective of the details of the tectonic or stratigraphic setting. The ability to judge the prospectiveness of a volcanic sequence by using whole rock geochemistry to evaluate its tectonic environment may prove useful in area selection at the grassroots exploration level."

Jan 1, 1991

By A. Baydusa, K. Barron

A theory for cutter roof failure in coal mines has been developed. It is shown that the key parameters influencing the likelihood of cutter roof failure are the rock strength, the vertical stress (depth) and the horizontal to vertical stress ratio. The support force necessary to prevent the development of this mode of failure is, in most cases, so high as to make it impractical to apply a force of such magnitude. It is, therefore, better to allow the failure to occur and to design a bolting system to support the dead weight load of the failed block. This is probably best achieved by using a yielding bolt system (such as split set bolts) which is anchored well beyond the top of the potential failure block. The maximum potential caving height determined from this theoretical approach compares favourably with field observations reported in the literature.

Jan 1, 1999

By C. O. Aksoy, P. M. Ozfirat, M. K. Ozfirat, C. Tatar, C. Pamukcu

"Temporal and other factors contributing to the occurrence of occupational accidents at an underground coal mine in Turkey between 1992 and 2000 have been analyzed. The time period of the study spanned the transition from hand-worked mining methods (1992 to 1996) to hand-worked mining methods and mechanized mining methods (1997 to 2000).The mine selected for the study employed an average of 5,835 men per year on three separate eight-hour production shifts for 302 d/y (Sundays are not worked, and there are 11 holiday days per year). Production on an annual basis averaged 190,000 tons per year between 1992 and 1996, and 300,000 tons per year between 1997 and 2000.The purpose of the study was to determine which, if any, of the factors studied contributed to the occurrence of accidents so that the mine could take the necessary steps to reduce the risk to the workforce. Regression analysis was used to determine the strength of the relationship between each factor studied and the number of occupational accidents.The strongest relationships observed were between the age of the employee, the day of the week, and the total yearly labour."

Jan 1, 2006

By Deepak Bhadouriya, Saurabh Singh, Aditya Raj Suman

"An experimental study of chemically enhanced filtration and dewatering of fine coal slurry with and without additives was carried out. The experiment involved determination of effect of slurry concentration, additives (cationic, anionic and nonionic), filter area, filtration velocity, particle size and cake resistance on dewatering and filtration using vacuum filtration cell. Finally, the rate of filtration and dewatering and optimum amount of additives used were determined under suitable filtration condition. Overall, it was found that the filtration and dewatering characteristics were enhanced by increased slurry concentration, larger filter area and larger particle size. In addition of additives, the kerosene was found to be best for enhancing the filtration which yielded cake moisture reductions of approximately 17% by weight. At optimum dosages, the final cake moisture contents were reduced by 3.6% and 5.8% by weight using the appropriate surfactant and flocculent, respectively.INTRODUCTIONFor India, it is estimated that coal constitute a principal source of energy for the next several decades. It is majorly used at thermal power plants to generate electricity and also to a great extent in steel and cement industry. It has been observed that its consumption is increasing so as to meet the energy requirements of the country. It has been found that in a coal preparation plant; approximately 20-25 percent coal is of the mined coal of the range below minus 0.5 mm (28 meshes). Generally, this fine fraction is discarded due to its high cost of processing and further utilisatisation is very minimal. But with ongoing research and development for advanced clean coal technology, various new techniques have been evolved to maximize the utilization of available coal. In recent time technologies such as column flotation, cleaning of fine size coal to lower the ash content and low pyretic sulfur is feasible at high recovery value. But in various researches it is found that one of the biggest hurdles in utilization of fine coal cleaning technology by the coal industry is the economic dewatering of the fine clean coal product. Thus, until an economical and practical solution to dewatering of fine clean coal is achieved, the efforts devoted to developing fine clean coal technology will be wasted. In this paper an effort toward enhancing and developing the optimum technique of dewatering and filtration of fine coal slurry has been made."

Jan 1, 2016

By D. M. Ziebarth

"Normal sequence of operations to develop a new underground mine is: construct and outfit headframe for shaft sinking, sink shaft, construct and outfit shaft sump, develop shaft station and shaft bottom steel. In an effort to reduce the overall project schedule, an innovative plan was developed to install service shaft steel below station level, prior to the completion of the shaft sinking effort. To better evaluate the construction of this substantial steel tower, a preliminary constructability evaluation was conducted, including the best method of supporting the main tower; from the bottom, middle or top of the tower. The design criteria and plan involved: •,Develop access from existing service shaft, 25 km underground •,Use of materials to maximize strength while minimizing corrosion exposure •,Estimating the location of the shaft centerline •,Over excavating the station and shaft below station to allow future shaft steel repositioning •,Designing the tower steel for modular installation •,Incorporate commissioning considerations, such as suspension of the cheese weights during steel installation •,Provision for covered stair access to shaft bottom •,Enclosed shaft envelope with open panels to allow visibility and ventilation The design approach was innovative and this paper will describe the design principles and challenges encountered while providing insight into the solutions developed and implemented; especially the modular construction and installation methodology. INTRODUCTION In an effort to expand the mining operations, a plan was developed to construct a new service shaft closer to the new mine workings and convert the existing service shaft to a production shaft at the Potash Corporation of Saskatchewan Inc. (PCS now Nutrien) Rocanville Potash mine in southeast Saskatchewan. The new service shaft required a multi roped friction hoist operating a cage / counterweight, rope guided conveyances to support the operational requirements. The service shaft is an integral part of the mining infrastructure as it provides access to the underground workings, transport personnel and materials underground for operation and maintenance of the mine. The shaft also allows for services required for safe operation of the underground mine, power supply, controls, communication, dewatering and fresh water supply."

Jan 1, 2019

By Dean Millar

Clean, green, cheap compressed air can be produced efficiently and renewably by modernization of a 19th century technology ?The hydraulic air compressor has no moving parts ?After commissioning, the Ragged Chutes HAC operated for 70 years, only being stopped twice for repairs to the intake heads ?Operates using hydropower from Montreal river ?Produced air for ~29 silver mines in Cobalt, 20 km distant

May 1, 2013

By Z. Jun, L. Kerning

Jinlong copper smelter and refinery, originally designed for 100,000tpa primary copper and started up in 1997, has been expanding its capacity on the basis of operational optimization and by modifying its facilities. Currently it is producing 210,000tpa primary copper, and the new phase of expansion project with a target capacity of 350,000tpa primary copper is ongoing. This paper reviews problems and improvements made with operation and equipment in the past years. Recent plant operation is briefly described. The expansion projects completed are summarized and the ongoing expansion project is present.

Jan 1, 2007

By Engineering Staff

"This paper briefly describes the surface mining operations at Smoky River Coal Limited (formerly McIntyre Mines Limited, Coal Division) near Grande Cache, Alberta. Geology, mining methods, equipment, manpower and reclamation and environment topics are discussed. Introduction Smoky River Coal Limited, a wholly-owned subsidiary of McIntyre Mines Limited of Calgary, Alberta, produces a high quality, low sulphur, low volatile bituminous coking coal from its minesite located at west central Alberta, approximately 20 km from the town of Grande Cache and 360 km west of Edmonton (Fig. I). Most of the coal property is contained within a 30 km long by 20 km wide block lying in a northwest-southeast direction in mountainous terrain. Elevations vary from 920 m above sea level ·at the plant·site on the Smoky River to 1,600 mat the upper levels of current and proposed mining operations. A total of 11 coal seams have been identified. Only two seams, No. 4 Seam and No. 10 Seam are currently considered of major commercial value. These seams are recovered by both surface and underground mining. Approximately 650Jo of the plant feed coal is obtained from a conventional shovel/truck surface mine; the balance is mined underground by room-andpillar methods. Background In 1921, McIntyre Mines Limited acquired some 26,300 hectares of coal leases at Smoky River. Since then the leases were explored intermittently by different companies including McIntyre. In the mid-l 960s exploration activities increased and several feasibility studies were completed. Development of the area was undertaken by McIntyre in 1968 and, in August of the same year, a long-term contract was signed with a consortium of Japanese steel mills for delivery of 2 x 106 t of clean coking coal for 15 years commencing in 1970. Production was focussed on underground mining, using longwall methods."

Jan 1, 1985

By M. Nagamori, A. J. Plumpton

"A low-grade concentrate from the Crevier Township, Quebec, containing 1.8% Ta205 and 13.7% Nb205 was reduced with carbon at 1600°C, and niobium and tantalum were selectively absorbed in liquid iron. To slag off the zirconia-rich gangue, some silica and lime were added as flux. Metallic iron was added in such a way that the combined contents of TaC and NbC did not exceed 20% in the ferroalloy . Up to 95% of the niobium, and up to 80% of the tantalum contained in the concentrate were recovered in the metal. The ferroalloy was ground finely and dissolved in 2 wt % sulphuric acid to leach out iron and silicon preferentially. The insoluble residue consisted principally of NbC and TaC, the calcination of which yielded an enriched concentrate comprising 80% Nb2O5 and 8% Ta2O5. The insoluble residue could also be chlorinated to obtain an impure liquid of Nb2Cl5 and TaCl5. Process variables and their effects are discussed in terms of higher metal recoveries in the smelting.IntroductionPresently, about one-third of the world production of tantalum comes from the pyrometallurgical reprocessing of tin slag, a by-product of tin smelting, containing sometimes 2 to 10% Ta205 and about the same amount of Nb205. Upon heating tin slags with carbon at about 1600°C in an electric furnace, tantalum and niobium oxides are converted to TaC and NbC, which are absorbed by the coexisting phase of molten metallic iron(1,2). The Fe-Nb-Ta-C melts cannot be decarburized by oxidation because of the preferential formation of Nb and Ta oxides over CO gas(3). So, the ferroalloys containing tantalum and niobium carbides are commercially treated by acid-leaching and I or chlorination to eliminate iron and thus permitting the eventual recovery of purified tantalum and niobium oxides(2).Absorbing Ta and Nb carbides in molten iron was first proposed and demonstrated by Zimmerley and Back(4) in 1957 in order to recover selectively tantalum and niobium from lowgrade concentrates. The process was successfully applied to the electric furnace smelting of tin slags by Hunter and Fursmant(5) over a period preceding 1965."

Jan 1, 1985

By O. Leuangthong, E. Schnetzler

"The McMurray formation in the Athabasca oil sands deposits of northern Alberta is part of the world’s second largest proven crude oil reserves. The formation is characterized by stratigraphic layers that correspond to three different depositional environments: Marine, Estuarine, and Fluvial facies. Resource estimation for oil sands has traditionally relied on polygonal and inverse distance schemes. These techniques are simple and straightforward in practice, but they do not permit reliable uncertainty assessment. This paper describes the modelling of the McMurray formation using modern geostatistical techniques.Geostatistical modelling should be performed within homogeneous geological facies. The methodology for geostatistical simulation within each of the identified facies involves: 1) assessing the most appropriate stratigraphic transformation for optimization of the correlation structure; 2) determining representative distributions with declustering and debiasing techniques; 3) modelling spatial continuity of the bitumen grade, fines grade, water saturation, and other petrophysical variables; 4) performing estimation and cross validation as checks against simulation results; 5) performing simulation for uncertainty quantification of bitumen and fines grade; and 6) model checking of simulation results against the input data, and comparisons against the kriged models. These steps are described in detail. The application of these models for uncertainty quantification in support of resource classification is also discussed."

Jan 1, 2006

By Y. Wang

In this study, homogeneous (unseeded) precipitation of nesquehonite (MgCO3.3H20) by the reaction of MgC12 with (NH4)2CO3 in supersaturated solutions at 30 °C was investigated. Factors which influence the precipitation of MgCO3.3H20, such as initial concentration, temperature, stirring speed, titration speed, equilibration time, have been studied. SEM images show that the initial concentration and titration speed have significant effect on nesquehonite's crystal morphology and particle size. In addition, stirring speed and equilibration time also have some influence on its properties. With the optimization of operating conditions, the crystals can grow up to a length of about 40µm and a width of 5µm, indicating good filtration properties. High purity nesquehonite obtained in this study was calcined to produce highly pure MgO at 800 °C as shown by XRD results. The novel process may be used to separate Mg and Li from high Mg/Li ratio brines in Qinghai, China.

Jan 1, 2007

By R. Matusewicz, A. Kaye

Ausmelt Top Submerged Lancing (TSL) Technology has gained widespread commercial acceptance in non-ferrous applications, including the processing of lead and zinc primary concentrates and secondary (post-consumer) materials. TSL is highly flexible and efficient, and is one of the few technologies which can process primary and secondary feeds, and use varying fuels, to deliver high recoveries and excellent environmental performance. With the recent high value of both lead and zinc, and an escalating awareness of the sustainable use of resources, focus on the processing of secondary feed material sources has surged. Ausmelt Technology has proven to be well suited to the economic recovery of values, with twenty-two (22) Ausmelt furnaces processing lead and zinc bearing feed sources now in operation, under design or construction. This paper describes Ausmelt's progress in the fields of lead and zinc processing, and developments in new processing areas such as EAF dust processing and linking to innovative hydrometallurgical technology. Ausmelt has recently committed to the Whyalla Zinc project as the owner/operator of a facility for the treatment of zinc bearing secondary feeds. This project is due for start up in the first quarter of 2008.

Jan 1, 2008

By R. E. Whitehead, G. J. Prior

"Abstract -Biotite from aplite that appears to have crystallized simultaneously with disseminated Cu-Mo mineralization at MacLeod Lake in northern Quebec yields K-Ar dates in the range 2032 ± 44 Ma to '2f1:)1 ± 47 Ma. The mean value, 2065 Ma, is some 400 Ma younger than the 2485 ± 64 Ma date obtained from a hornblende concentrate separated from a granodiorite sill that is spatially, but apparently not genetically, associated with the disseminated Cu-Mo deposit. The mean biotite date of 2065 Ma at MacLeod Lake, a K-Ar date of 2055 Ma reported from an area 50 km east of MacLeod Lake and published dates of about 2000 Ma for galenas from the Chibougamau Cu-Au ores, suggest a widespread thermal and mineralization event, in that part of the Superior Province east of James Bay, that differs from the common late Archean mineralization that is related to volcanism and metamorphic-intrusive activity.Sommaire - Les datations au K-Ar sur des biotites qui auraient cristallisé en même temps que la minéralisation disséminée en Cu et Mo dans une aplite mise en place au Lac MacLeod, au nord du Québec, s'échalonnent entre 2032 ± 44 Ma et '2f1:)1 ± 47 Ma. La datation moyenne, soit 2065 Ma, est d'environ 400 Ma plus récente que la datation obtenue pour un concentré de hornblende extrait d'un fùon-couche de granodiorite qui est spatialement mais ne serait pas génétiquement as­ sociée à la minéralisation disséminée en Cu et Mo. La datation moyenne de la minéralisation au Lac MacLeod, soit 2065 Ma, la dataion au K-Ar à 2055 Ma citée pour une région à 50 km à l'est du Lac MacLeod, de même que les datations d'environ 2000 Ma établies pour des galènes qui se trouvent dans le minerai aurifère et cuprifère à Chibougamau, suggèrent un phénomène thermique répandu qui aurait produit la minéralisation dans cette région à l'est de la Baie James, dans la province du lac Supérieur. Ce phénomene serait différent de celui qui aurait produit la minéralisation répan­ due d'âge archéen tardif qui elle serait associée à l'activité volcanique et à l'activité intrusive accompagnée de métamorphisme."

Jan 1, 1992

By Hang Zhao, Xinping Li, Pingan Wu, Yi Luo

"The deep-buried rock surrounding the Jinping II Hydro-power Station was taken as the engineering background. Using model specimens of classified rock materials to simulate fractured rock mass under high in-situ stress conditions, the test about acoustic propagation law on single fracture model of specimen under different pressures and different angles were carried out. The variation of p-wave velocity in fractured rock mass and axial stress-strain relationship in the whole test procedure was also studied. Based on damage mechanics principle and the acoustic wave propagation in cracked rock mass, comparative study on damage constitutive relation of fractured rock mass under high in-situ stress in consideration of equivalent strain and equivalent energy was performed. As the results showed, with the change of axial stress level under constant confining pressure, the change in wave velocity can be divided into three stages: slow increase (small variation in amplitude), rapid reduce (large variation in amplitude ) and accelerate reduction. When the confining pressure is constant, the maximum p-wave velocity and the peak strength of specimens increases with the decrease of the crack angle.When the crack angle is constant, the maximum p-wave velocity and the peak strength of specimens increases with the increase of confining pressure.It is identified that the theoretical calculation results of constitutive relation about elasto-plastic damage model containing variable wave velocity in the fractured rock mass is consistent with the model test results.Therefore,the constitutive relation can provide reasonable suggestions for engineering practice. INTRODUCTIONThere are a lot of joints and fractures in surrounding rock mass of deep-lying in the Jinping-II hydropower station, which has a great influence on the physical and mechanical properties of rocks and effects the acoustic wave propagation and attenuation law in rock. Many previous research and project examples has proved that sound propagation parameters are closely related to crack and stress condition. Thus, it has certain theoretical significance and practical application value to carry out researches on sound propagation characteristics and establish damage constitutive model of fractured rock mass which is related to sound propagation parameters."

Jan 1, 2015

By W. J. Farley

"The Sherritt Gordon mine is 100 miles north of The Pas in northern Manitoba. Copper-zinc ore was discovered on the property in 1922. Production began in 1931 and continued to June, 1932, when operations were suspended because of the low price of copper. Operations were resumed on August 1st, 1937, and have been carried on continuously from that time to the present (March 1947). The production of metals up to the end of 1945 was copper, 287,129,880 lb.; zinc concentrate (50 per cent) 104,419 tons ; gold, 79,388 oz.; silver, 2,529,974 oz.GENERALThe ore occurs in two deposits, the east and the west. Both are enclosed in gneisses that are highly metamorphosed sedimentary and volcanic derivatives. The rock beneath the deposits, and hence forming their footwall, is gneissoid quartzite; the hanging-wall rock is basic garnetiferous hornblende gneiss. Pegmatite commonly occurs along both foot- and hangingwall peripheries and as isolated blocks and fragments within the ore zone . These blocks and fragments are considered to be residuals of unreplaced host rock .The ore is relatively coarse grained and ranges from the massive to the disseminated type. The metallic sulphides composing these, named in the order of their abundance, are pyrite and pyrrhotite ( 2-1 ratio) , chalcopyrite, sphalerite (marmatite) , and minor chalmeriite; subordinate amounts of gold and silver are recovered . The insoluble content of the ore averages about 35 per cent.Another deposit known as the Bob Lake, much smaller and lower in grade but having very similar relationships, occurs about 3 ½ miles to the northeast of the main Sherritt Gordon ore masses.STRUCTUREThe Sherritt Gordon orebodies are of the replacement type, and lie within a pegmatite sill that has been intruded along a contact between quartzite and hornblende gneiss. The two main orebodies are intimately related, for the east deposit is an erosional remnant of the lower, easterly limit of an orebody once continuous with the west body. The ore lies along the southwest limb of an overturned syncline."

Jan 1, 1954

By J. R. Rau

While refuge chambers are common place in most underground mining projects, there are different philosophies as to what life support systems are to be considered and how these systems are to be applied. Case studies in the underground mining industry have examples of emergencies where the external compressed air and power supply to the refuge chamber were compromised due to proximity of services to the fire location. In 2005, The Department of Industry and Resources, Western Australia, drafted guidelines that listed specific requirements for refuge chambers which included a secondary life support system that would operate independently of external sources. The objective of this document is to examine what critical life support systems are essential for safe entrapment in the event of an emergency and to examine considerations for their application.

Aug 1, 2013

By T. Marolt, J. Likar, E. Grøv, J. Žarn

"Underground structures are an integral part of the infrastructure of modern society and are used for a wide range of applications, including subways and railways, highways, not at least nuclear facilities. When the wider area is subject to earthquake activity, underground constructions should be analyzed on seismic and static loading. Observations showed that the underground structures have significantly less seismic risk than surface structures. Available methods allowed analyzing the magnitude of risk for different input parameters of seismic loads in different ground environment. Simulation of earthquake loading on underground structures, in the present paper is given the various aspects of analyzing the potential damage and instability of underground facilities. INTRODUCTIONThe development of methods and computing resources used for para-seismic engineering has finetuned the evaluation of the seismic strength of buildings and equipment. Reinforcements may therefore be decided, not simply on the basis of a reassessment of the hazard, which constitutes input data for the calculation of structures and equipment, but also on the basis of developments in para-seismic engineering. Underground facilities are an integral part of the infrastructure of modern society and are used for a wide range of applications, including subways and railways, highways, material storage, and sewage and water transport and not at least nuclear facilities. Although in the past showed that the underground structures are significantly less seismic risk than on the surface, the professional researches and their results are accessible. Seismic resistance of underground structures is analyzed from several aspects. The currently available methods allowed analyzing the magnitude of risk for different input parameters of seismic loads in different ground environment. For better interpretation of earthquake loading on underground structures, are given below the various aspects of analyzing the potential damage and instability of underground facilities in rock. One of the early studies which covered this are of investigation were prepared by Dowding and Rozen (1978). They grouped damages due to earthquakes in underground structures into three main categories:- damage from ground shaking- damage from fault dislocation- damage by earthquake-induced ground failures (e.g. liquefaction and landslides)."

Jan 1, 2015