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By J. Kuipers, R. W. Lawrence, P. B. Marchant, W. Brooks, J. T. Chapman

"Bioleach testing and piloting was conducted on refractory gold sulphide concentrate from Austin Gold Venture in Nevada during 1988. The objective of the test programme was to determine the technical and commercial viability of bioleaching as a concentrate pretreatment step prior to gold extraction by cyanidation. Baseline CIL cyanidation typically resulted in < 20% gold extraction from the Austin concentrate. Bioleaching enhanced gold extraction up to 95% using conventional CIL techniques. This paper summarizes the bioleach test programme and results, including pilot plant studies onsite, and describes the commercial design details for a possible retrofit of the Austin flotation tailings leach circuit to accommodate 20 tpd and 40 tpd capacity concentrate bioleach facilities.INTRODUCTIONBioleach testing on a refractory carbonaceous sulphide concentrate from Austin Gold Venture (AGV), was initiated in late 1987 as part of an ongoing programme at Austin to investigate alternatives to concentrate smelting. Preliminary batch biooxidation tests at Coastech indicated that over 90% gold extraction by carbon-in-leach (CIL) cyanidation of the bioleach residue could be achieved, compared with less than 20% gold extraction on untreated concentrate by similar CIL processing.Subsequently, a more rigorous laboratory study was undertaken at Coastech to establish continuous biooxidation operating criteria on a bench scale. The objective of continuous testing in the laboratory was to provide confirmation of enhanced CIL response based on continuous bioleach products and to determine key process operating and design parameters for pilot testing. The success of the laboratory test program led to the installation of a mobile pilot plant at Austin Gold Venture. The plant was operated by Coastech and AGV during 1988 to provide scaleup data and design criteria for commercial design and feasibility analysis. Based on pilot plant operating data, a detailed commercial bioleach plant was designed as a possible retrofit to the existing 1000 tpd CIL plant. Capital and operating costs were estimated to provide a commercial feasibility study of bioleaching as an oxidative pretreatment for Austin refractory concentrate."

Jan 1, 1989

By Nick Vagenas

"Loading and transportation are important activities of the mining process. Automation of these activities in underground hard rock mining has been discussed for a long time. This paper deals with the performance evaluation of a prototype automatic Load-Haul-Dump (LHD) vehicle (a 7-ton GHH LF LHD model) operating in Zinkgruvan mine, Sweden. The purpose of the data analysis is to evaluate the operational and maintenance characteristics of the automatic LHD system in the mine. Graphical and numerical methods have been used for the statistical analysis of the data. IntroductionDuring the past years, the idea of integrated automation and tele-operation on Load-Haul-Dump (LHD) machines (Fig. 1) has attracted considerable interest in the Swedish mining industry. This is mainly due to the demand for improvement in the working environment and due to the rapid development of economic and reliable microprocessors for mining vehicles. Several advantages can be foreseen with the application of a Remote-controlled/Automatic LHD (RAL) system in underground mining. Some of them are (1)&apos;:• better utilization of working hours;• less interruption in production at shift changes;• better operational control of a fleet of vehicles;• improved safety; and• one operator may be able to operate more than one vehicle simultaneously."

Jan 1, 1993

By Vlad Ruzicka

"Uranium deposits in the Rabbit Lake-Collins Bay area are associated with the sub-Athabasca unconformity which separates crystalline Archean or Aphebian basement rocks from Helikian clastic sedimentary rocks of the Athabasca Group. The basement rocks are a part of Wollaston lithostructural domain.Most of the high grade deposits, such as Collins Bay ‘A’ and 'B' Zones and Eagle Point are associated with altered rocks of the basal unit of the Wollaston Group. Some deposits, such as Raven and Horseshoe are confined to the uppermost unit of this Group. The Rabbit Lake deposit occurs in the middle, meta-arkose unit of the sequence. Locations of some deposits (Rabbit Lake, Collins Bay ‘A’ and 'B' Zones) are also controlled by thrust faults, such as Rabbit Lake Fault and Collins Bay Fault.The deposits contain either monometallic (uranium) mineralization (Rabbit Lake, Raven, Horseshoe) or polymetallic (mainly uranium-nickel) assemblages (Collins Bay “A’ and 'B' Zones).IntroductionThe Athabasca Basin region, a part of the Churchill Geological Province of the Canadian Shield, is composed of Archean and Aphebian crystalline basement and younger, Helikian, unmetamorphosed supracrustal rocks. The Rabbit Lake-Collins Bay area is situated at the eastern margin of the Athabasca Basin region, which hosts a substantial proportion of Canadian uranium resources.The crystalline basement complex was subdivided by Lewry and Sibbald (1979) into lithostructural domains and these domains were grouped into major crustal units designated, from northwest to southeast, as Western Craton, Cree Lake Mobile Zone, consisting of Wollaston, Mudjatic and Virgin River domains, and Rottenstone Complex (Fig. 1)."

Jan 1, 1986

By Jan E. Nesset, L. Paul Staples

"High Gradient Magnetic Separation (HGMS) technology, although developed over 2 decades ago, has not been widely applied to the separation of sulphide minerals. Under conditions of strong magnetic field gradients, weakly magnetic minerals such as chalcopyrite (CuFeS2) and marmatite (Zn(Fe)S, sphalerite with iron in solid solution) behave paramagnetically and can be effectively separated from diamagnetic minerals such as galena (PbS). The application of this technology to the separation of Cu-Pb and Zn-Pb bearing streams in the treatment of fine grained complex sulphides may in some cases be more effective than separation by flotation. A 2 TPH Sala HGMS pilot plant was operated at Brunswick for a nine month period, ending in March 1995. The testing demonstrated the mechanical reliability of the technology, the consistency of operating results and the scale up from laboratory testing. HGMS is seen as a complimentary technology to flotation, best suited to performing those separations of galena (and other diamagnetics) which flotation does not do as well.IntroductionBackgroundSince the turn of the century, the magnetic character or magnetic susceptibilities of minerals have been determined with increasing precision and accuracy. Figure 1 illustrates specific magnetic susceptibilities of some common minerals. As long as susceptibility ranges do not overlap, separation is possible.In 1937, the principle of using a magnetizable matrix material in a magnetic field to increase both magnetic flux density gradients and number of capture sites for susceptible minerals was first applied (Frantz). It was not until the 1970's, however, that the genuine development of wet high gradient magnetic separation began with the introduction of very fine matrix materials to the magnetized volume of large solenoid magnets. Today, dozens of HGMS units purify, filter and separate minerals, primarily for the removal of iron stained minerals from clays used in the paper coating and china clay industries and for the recovery of fine titanium and iron oxides in the iron ore industry. Only the Garpenburg mill in Sweden is currently applying a continuous HGMS machine to separate complex sulphide minerals; upgrading a lead concentrate since 1988."

Jan 1, 1996

By M. Sutherland

"Increased efforts to improve mine safety have led to various successful forms of ground control in Canadian underground mines. At Inca Limited&apos;s T-3 Mine in Thompson, Manitoba, a perimeter blasting method has been implemented in jumbo drilled development headings.The technique utilizes an increased number of perimeter blast holes in the drill pattern while decreasing the linear charge density of explosives in any individual perimeter hole. The decrease in perimeter charge density means less blast damage to the surrounding structure.The benefits realized include increased safety through less loose ground and substantially less scaling time, less overbreak and improved long-term drift stability. This paper highlights the development and implementation of the perimeter blasting program.IntroductionThompson Mine Thompson Mine is a 6000 ton per day underground nickel mine located just outside the city of Thompson, 400 miles north of Winnipeg. The mine is serviced by the T-I shaft and by the T-3 shaft. The shafts are 10 000 ft apart and are connected on several levels with the deepest operating levels at T-1 and T-3 being 4000 ft and 2400 ft respectively.The T-3 Mine presently produces 52% of the total Thompson Mine production and 65070 of the 3000 ft of mine development each month. Current development of the 5 million ton 1, C orebody below 2400 level at T-3 will maintain these production and development ratios.Depending on equipment requirements, development headings at T-3 Mine vary in size. The 1, C ramp, at 17 1/2 ft wide by 10 1/2 ft high, is presently the largest development heading at T-3. Fifty- two per cent of the development footage is done with four Gardner Denver two boom electric /hydraulic jumbos and one Gardner Denver one boom electric /hydraulic jumbo. The remaining 48% is driven with hand-held jack-leg drills."

Jan 1, 1990

By Z. M. Zavodni, C. D. Broadbent

"Major rock slides in open-pit mines are rare, but they can develop in spite of sophisticated slope engineering design practice. Experience has shown that, except under high seismic load conditions, the serious slope instability condition is almost always accompanied by the gradual development of one or more tension cracks behind the slope crest, allowing for time-displacement monitoring. Continuous surface displacement measurements with attendant prompt analyses are usually adequate for the prediction of slope behaviour.This paper describes efforts that have been made to quantify parameters associated with slide movement, and compares the displacement records of several large-scale open-pit porphyry copper mine slope failures. Two principal failure stages are recognized in the typical slope failure leading to total collapse: (a) REGRESSIVE STAGE, during which the failure will re-stabilize if some disturbance external to the rock and structure is removed; and (b) PROGRESSIVE STAGE. during which the failure will gradually displace at an accelerating rate to the point of total collapse unless active control measures are taken. Over-all displacement records in both failure stages are apparently of simple exponential form. with a definite break occurring at the onset-of-failure point.Certain common empirical relationships are suggested for the large-scale slope failures analyzed in this study. Based on plots of displacement rate vs time prior to collapse, a semi quantitative empirical relationship is presented for failure collapse prediction. The comparison of historical slide displacement records furnishes the operating engineer with practical guidelines to estimate the characteristics of future large-scale slope failures."

Jan 1, 1980

By J. -P. Tshibangu, M. Ramos da Silva, F. Descamps, C. Schroeder, J. -C. Verbrugge

"The mechanical behaviour of rock materials is largely influenced by the stress state and pore pressure; this needs to be considered in many applications, such as petroleum engineering, tunnelling or stability of underground excavations.Conventional triaxial tests (d2 = d 3) are generally used to assess the influence of confining and pore pressure. In this work, those tests are performed on a porous rock named Sorcy limestone, along with more advanced stress paths like triaxial extension (d 2 = d 1) and purely deviatoric tests with independent pore pressure control. Those tests are combined to a true triaxial study on the dry rock in order to investigate the effect of true triaxial stresses and, hence, build three-dimensional limiting envelopes accounting for the influence of pore pressure.Three-dimensional limiting envelopes of dry Sorcy limestone are built in meridian and octahedral planes. The shape of the octahedral sections changes with the mean stress from triangular to hexagonal and then quasi circular. At even higher mean stresses, the evolution continues towards a triangle with apexes oriented in the direction of triaxial extension stress states. In meridian sections, the deviatoric stress first increases with the mean stress. The transition between this deviatoric mechanism and the cap surface occurs at different mean pressures depending on the Lode angle.Terzaghi’s effective stress is found to govern the yield and plastic behaviour of saturated Sorcy limestone. Triaxial tests show that the limiting envelope does not depend on the loading path (conventional compression and purely deviatoric stress paths). In triaxial extension, the brittle-ductile transition is observed for a higher mean pressure than in triaxial compression, as previously found for true triaxial tests on the dry rock.Finally, it is shown that upon appropriate normalisation, the dry and saturated yield envelopes come very close one to each other. This suggests that only the size of the yield envelope changes between dry and saturated state (pore pressure = 5 MPa); its shape does not seem to evolve."

Jan 1, 2015

By R. F. Favreau, R. A. Morin, G. W. Kuzyk, P. J. Babulic, N. J. Tienkamp

"Atomic Energy of Canada Limited is constructing an Underground Research Laboratory (URL) as part of a comprehensive program to evaluate the concept of nuclear fuel waste disposal deep in crystalline rock formations. Careful blasting methods have been used to minimize damage to the excavation surfaces. Good wall quality is desirable in any excavation. In excavations required for nuclear waste disposal, the objective will be to minimize blast-induced fractures which may complicate the sealing requirements necessary to control subsequent movement of groundwater around a sealed disposal vault. The construction of the URL has provided an opportunity for the development of controlled blasting methods, especially for drilling accuracy and optimization of explosive loads in the perimeter and cushion holes. The work has been assisted by the use of blast simulations with the mathematical model Blaspa.This paper reviews the results of a recent project to develop a controlled method of full-face blasting, and compares the observed field results with the results of a blast simulator called Blaspa. Good agreement is found between the two, and the Blaspa results indicate quantitatively how the blasting may induce damage in the final excavation surface. In particular, the rock in the final wall may be stressed more severely by the cushion holes than by the perimeter holes. Bootleg of the rock between the perimeter and cushion rows occurs when the burst out velocity imparted to it by the explosive loads in the perimeter holes is inadequate. In practice, these findings indicate that quantitative rock stress and rock burst-out velocity criteria can be established to minimize wall damage and bootleg. Thus, blast simulations become an efficient way to design controlled blasting and to optimize quality of the excavation surf ace."

Jan 1, 1989

By Todd S. Harris

"IntroductionThe western region of North America has long been considered a dynamic market supporting such diversified industries as lumber, agriculture, cement, and electronics. In recent years however, the region has also been the focus of a great deal of activity in the extender and filler mineral s business from companies seeking to position themselves to take advantage of the large demand for these materials both here and abroad.Extender and Filler MineralsExtender and filler mineral s include 15different products used in numerous end uses. The nine most important extenders and fillers are listed in Table I. These products range in price from under $50 a ton to over $4,000 a ton and basically represent the following three different types of minerals:Particulate products-Calcium carbonate; Kaolin; Silica.Platy minerals-Talc (Montana, Canada); Mica.Fibrous minerals-Talc (California, Eastern U.S .A.);Wollastonite.What distinguishes these products from other industrial minerals? For one thing, an important feature of extender and filler minerals is that they are used primarily in such consumer non-durable good s as paper, paint, plastics, sealants, and rubber which traditionally do not react as violently to swings in the economic cycle. In addition, these minerals are sold principally on key physical properties, usually brightness, particle size and shape, oil absorption, and hardness. As part of the physical minerals segment of industrial minerals, extenders and fillers are traditionally the most stable group and typically the most profitable. Studies by C.H. Kline over the past decade on extender and filler minerals has revealed historic average profitability (expressed as a percentage on sales) nearly double that of most other industrial mineral s.The demand for these minerals in the western region (Fig. 1), closely follow s the areas of greatest population concentration. These markets include pulp and paper, mainly in the Pacific Northwest, and paint, around Los Angeles and San Fran cisco. Other significant markets for extender and filler minerals in western North America include joint cements, carpet backing, and plastics, mainly PVC pipe."

Jan 1, 1986

By Christopher Riley

A relatively unexplored lead zinc deposit lies about 12 miles northwest of Revelstoke, B.C., in the highly metamorphosed Monashee Group of rocks of the Shuswap Terrane, Precambrian in age. Host rocks are of sedimentary origin and consist of gneisses, schists, marbles and quartzites with intermediary types. The marbles and quartzites provide good horizon markers. Using these it is possible to interpret the controlling structure which is a syncline overturned to the north, dipping south at about 45°, and plunging east at about 12°. The syncline is truncated at about halfway of its length on a peak on the west side of which a partial cross section together with superimposed minor folds may be seen. The quartzites and the two marble beds may be traced over much of the structure. There are two lodes, above the marble and below the quartzite, which converge eastward and which are the exposed edges of the same host bed -an impure limestone.

Jan 1, 1961

By L. S. Brooks

TIMBER HANDLING presents a problem for any mine where appreciable amounts are used. This problem is accentuated where the shaft compartments are too small to allow a loaded timber truck to be lowered in the mine cage. When Normetal Mining Corporation, Limited, found it necessary to resort to square-set mining it faced this problem of getting large quantities of timber down a shaft that was also required for hoisting ore. A &apos;timber car&apos; that could be suspended under the cage was developed to overcome this difficulty. Production started at the Normetal mine in 1937, at the rate of 250 tons per day. In 1938 a winze, known as No. 3 shaft, was sunk from the 800-foot level ?to the 1,385-foot level. This was later raised to surface and then deepened to 3,275 feet in three stages and became the main production shaft. The portion of the mine below the 3,070-foot level is serviced by a winze, locally referred to as No. 4 shaft, which has been developed for stoping down to the 3,990-foot level and which has been deepened to the 5,365-foot level. No. 3 shaft has two hoisting compartments, each 4 ft. 6 in. by 5 ft. 0 in. inside the timbers, through which the ?ore must be hoisted and timber and supplies lowered.

Jan 1, 1956

By Burden of Occupational Cancer in Canada Project Team, Demers P. A., Kim J., Arrandale V. H., Jardine K.

"In 2012 diesel engine exhaust (DEE) was classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and is one of the most common workplace carcinogens internationally. We estimate that approximately 2.4% of lung cancers (n=560) and a suspected 2.7% of bladder cancers (n=200) are attributable to occupational exposure to DEE annually in Canada. High levels of exposure to DEE in mining results in a disproportionate number of cancers in this sector (approximately 220 lung and 20 suspected bladder cancers annually). These could be prevented by reducing the number of workers exposed and level of exposure. KEYWORDS Bladder cancer, Diesel engine exhaust, Economic burden, Lung cancer, Mining, Occupational cancer, Prevention, Regulation INTRODUCTION Diesel engine exhaust is a complex mixture of gases and particulates containing known and suspected carcinogens such as benzene, polycyclic aromatic hydrocarbons (PAHs), and metals. Approximately 900,000 Canadians are exposed to diesel engine exhaust at work, making it the most prevalent occupational lung carcinogen in Canada (CAREX Canada). Diesel engine exhaust is recognized as one of the most common workplace carcinogens in the world, but its classification as a human carcinogen by the International Agency for Research on Cancer (IARC) was relatively recent. In 2012, after decades of mounting evidence, diesel engine exhaust was upgraded from a probable (IARC Group 2A) to a definite human carcinogen (IARC Group 1) (IARC, 2014). The IARC evaluation was based on strong evidence in humans for an increased risk of lung cancer, as well as strong evidence in animal studies. The key human evidence considered by IARC was from epidemiologic studies of workers in truck transportation, rail transportation, and mining industries, where the use of diesel engines is widespread. These studies provided strong sufficient evidence for an increased risk of lung cancer, as well as limited evidence for bladder cancer. The human studies used particulate matter, generally measured as elemental carbon (EC) or total carbon, as a surrogate for diesel engine exhaust to assess the risk associated with level of exposure. The animal studies reviewed by IARC showed sufficient evidence for cancer with exposure to whole diesel exhaust and the particulate matter fraction of diesel exhaust, but not for the gas phase components."

Jan 1, 2019

By D. Sbarbaro

In many modem concentrators the use of supervisory systems in their grinding circuits has meant more consistent operations and increases in capacity. These systems rely on a series of specific algorithms that uses different pieces of information and drives actions over the process. One of these algorithms is the ball mill overload detection, which plays an important role in any supervisory strategy designed to maximize ore feed rate in wet grinding circuits. This paper introduces different overload detection algorithms, and compares them in terms of the time taken to detect the overload condition. This comparative analysis is based on highly noisy power draw measurements obtained in an industrial plant.

Jan 1, 2007

By Joseph H. Harris

Shebandowan Mine presents a unique opportunity for the mining industry to demonstrate its willingness and ability to use electrical energy effectively. The mine is a typical 250D-ton/day operation supplied by a i5-MVA power transformer. it is a recent, up-to-date design and operates on a four-day/week, two-shift/day basis. The paper outlines an energy profile based on historical data. It accurately describes the individual and total energy input For: (1) production and non-productive junctions; (2) production and down-time periods; (3) peak and average activity levels; and (4) principal energy utilization equipment. A comparison is then made of production data to electrical data, and production and electrical data to design data. The paper concludes that energy management has an important benefit for the mining industry by assisting in maintaining a competitive operation through reduced costs and fewer production slow-downs in the event of energy shortages.

Jan 1, 1979

By Robert B. Parsons

"Thrashing one&apos;s way through a jungle of entangled tax rules is no easy task today, as Canada&apos;s legislators continue to complicate this country&apos;s income tax laws. At some magical point, there is presumably some balance to be struck between legislation which is equitable and unambiguous on the one hand, and at the same time is efficiently complied with and administered. It is becoming increasingly clear that the legislation is not in balance, and that there is a pressing need for some simplification of the income tax rules and regulations especially in areas of critical importance to the resource industries-even though such simplification will likely involve some sacrifice of equity and certainty.Introduction""I would wish that ... the superfluous and tedious statutes were brought into one sum together, and made more plain and short, to the intent that men might better understand them."" Edward VI, King of England 1547-1553.Regal decree notwithstanding, the legislation of most developed nations continues to become more complex, lengthy, and confusing than ever before. Canada&apos;s income tax system cannot escape the accusatory finger pointing at examples of this serious problem which plagues all of us today.Although many areas of our tax law could easily warrant some degree of simplification, for those who are involved with this country&apos;s resource sector, that horrendous, almost unreadable, part of our tax legislation which deals with resource taxation must be regarded s a prime candidate for simplification. In recent decades, but particularly in the past ten years since tax reform in 1972, budget after budget, both federal and provincial, have amended, massaged, modified, and manipulated the resource tax rules to the point where not only are taxpayers totally lost in their attempts to make some sense of the entanglement of rules, but also the draftsmen themselves acknowledge that the outer limits of complexity are being reached, and that the whole set of rules is on the verge of grinding to a groaning halt under its own weight of nonsense and frustration."

Jan 1, 1982

By Shinji Muraishi, Shinji Kumai, Yasutaka Kedo, Takashi Kambe

"Magnetic pulse forming (MPF) is one of the extreme high-speed forming processes. A metal sheet which is accelerated by electromagnetic force is collided onto a mold and fine and sharp details of the product can be obtained. The deformation mechanism of the MPFed metal cannot be understood only by the microstructure observation of the deformed metal. The deformation behavior of the metal should be investigated also by considering the local microstructure change with strain, strain rate and temperature change during deformation. Numerical analysis is an effective method to achieve this requirement. In this study, pure Al and Cu sheets were deformed by MPF. Impact velocity of the metal sheet was calculated by using ANSYS Emag-Mechanical. Based on the obtained impact velocity, the deformation behavior of the metal sheet was reproduced, and local strain, strain rate, and temperature were analyzed by using ANSYS AUTODYN. The relationship between the local microstructure change of Al and Cu sheets and the deformation parameters was examined.INTRODUCTIONMagnetic pulse forming (MPF) is one of the high-speed forming processes using electromagnetic force. Fine and sharp details of the product can be obtained, and springback after deformation is extremely reduced in comparison to the conventional forming processes(Psyk, Risch, Kinsey, Tekkaya, & Kleiner, 2011). Figure 1 shows a schematic diagram of MPF. A metal sheet is placed over the coil in the discharge circuit. The discharge current runs through the coil, and magnetic fieldis producedaround the coil. An eddy current is inducedin the metal sheet. Interaction between magnetic field and eddy current creates electromagnetic force. The metal sheet accelerated by electromagnetic forcecollides ontothe mold. Forming is completed in a few tens of micro-seconds.MPF is suitable for metals with a high electrical conductivity like Al and Cu.The MPFed metal may have characteristic microstructure because of high strain rate deformation."

Jan 1, 2018

By J. Koponen, M. van de Vijfeijken, L. Bos

"The availability and reliability of large grinding mills and their Gearless Mill Drives (GMDs) are of paramount importance for the grinding process. Although GMDs have been in service for decades, and are known for their operational efficiency (reliability and robustness with reduced operating cost per ton), compared to conventional drives, in the last decade due to certain reasons some failures led to serious unscheduled shutdowns and significant insurance events.The majority of these notable ""insured"" failures have happened on GMDs installed on relatively large mills, as the financial impact of a failure is proportional to the through-put of the mill. Despite the occurrences of these events, as mining operations are driven by lower ore grades and the ability to continue reducing operating costs per ton, the trend for having larger mills is still very present and there is no reason why this trend should not continue.It is obvious that if not handled correctly, the possibility of large value GMD loss events, coupled with the continuing increase in mill size or required availability and reliability targets, could potentially lead to major conflicts as it becomes difficult for the insurance companies to judge the risk and hence may result in hesitation to insure these grinding circuits. This paper will not only describe the conflicting situation from both an insurer&apos;s perspective and from an equipment supplier&apos;s perspective, but also how these conflicting challenges can be successfully mastered. It has to be noted that not only the mining companies themselves, but also their insurance companies and the involved equipment suppliers have a common interest: to reach the highest availability and reliability in order to avoid or at least minimize unscheduled shut down times, and most importantly prevent unplanned events that result in extended production stoppages or reductions in through-put of GMD driven mills.From the very beginning onwards, the complete service concept together with emergency plans must be integrated on every level in the design of the grinding circuit. This approach must be implemented continuously and without compromises by all involved parties during all following stages, such as basic design, detail design, manufacturing, quality inspection and testing, packing, transportation, storage, installation, commissioning, operation and maintenance. The concept of formal risk analysis related to mill operations, maintenance and spare parts strategies must be an integral part of mining companies’ decisions related to the selection for installation and continued use of large mills powered by GMDs. The service concept in place for operating mills shall also have a clear focus on very early detection of any abnormalities, so that the risk can be mitigated and unscheduled shutdown times avoided. However, if a major failure occurs, then procedures and tools shall already be available in order to ensure that production impact is minimized."

Jan 1, 2012

By J. B. Evans

"NORMALLY the duties of the exploration engineer and geologist cover the initial, and possibly, the most important phase of mining property evaluation; that phase being the presentation of an opinion of the property's ore reserve potential in terms of tonnage and grade. The prime objective of this pa-per is to outline one method of bridging the wide gap that lies between a know ledge of a property' s tonnage and grade potential and an appreciation of the value of that property in dollars and cents.THE PRESENTATION OF PROPERTY EVALUATIONThe engineer engaged on a mining property evaluation, regardless of whether he be an independent consultant, or a company employee, has as his goal, the presentation of his appreciation of the property's potential value or worth within terms of reference acceptable to his principal.To furnish a complete evaluation report, the evaluator must firstly study all aspects pertaining to the particular property under consideration, then present his appreciation of the property's worth in some tangible form. The ultimate presentation is one giving a Present Value of the pro pert y in terms of monetary exchange. Such an idealistic presentation is not always possible; typical preventives being -insufficient reliable information, limited time, Jack of ability and absence of definite direction."

Jan 1, 1960

By A. Mcdonald

"An X-Met Analyzer was purchased from Outokumpu in late 1983for use in the Hudson Bay Mining and Smelting smelter. Its first use was in the fuming plant to give zinc assays of each charge of slag tapped from the fuming furnaces. This quickly told the operators exactly when each charge had reached its economic tap-out point, and gave supervision a fool-proof method of identifying good operation. These and other factors led to major improvements in coal utilization in the fumers and to major increases in zinc oxide production. A second unit was later purchased for the reverberatory furnace to give silica and iron assays of the slag, and these were used to make adjustments in the feed composition to maintain the desired SiO2:Fe ratio in the slag. Since purchasing the units for the furnace, the oil consumption and copper content of the slag have dropped significantly. IntroductionSmelters have lagged far behind concentrators in process control by mean s of rapid product analysis. The on-stream X-ray analyzer was developed about seventeen years ago, and soon concentrators around the world were getting assays of the incoming ore, .concentrates and tailings every fifteen minutes, and using these to control reagent additions and other process variables. Almost always, the concentrate grade and recovery improved.In smelters, product streams are solids or molten materials, not the more easily handled slurries, and until seven years ago no inexpensive equipment was available to provide rapid analysis of this type of material. In approximately 1980, several companies developed instruments based on irradiating solid samples with low-intensity gamma rays from radio-isotope sources, and measuring the secondary X-rays emitted from different elements in the sample to provide an analysis of the elements desired.The smelter staff had a close look at what was needed and listed the following points as being critical:1. ability to provide Zn assays of a sample of slag within 15 minutes of taking it, in order to achieve optimum fuming times (zinc fuming , being a batch process, had the greatest potential benefit from rapid slag analysis);2. ability to give Cu and Fe assays on the slag, and on other smelter products, such as matte and converter slag;3. ability to give Si02 assays since the SiO2 content of the slag has a strong effect on fuming rate; and4. ability to stand up to an industrial atmosphere such as exists in the fuming plant."

Jan 1, 1987

By R. D. Brown

In view of the many changes which have taken place since 1950 in the rules of the Income Tax Act concerning the deduction of exploration and development expenses, many corporate taxpayers each year face the tedious task of determining which particular rules their unclaimed exploration and development expenses are subject to and in what sequence these expenses are to be claimed. Recent amendments to the Act have cleared up some of the mystery of the "ordering" of these deductions. This article examines the sequence in which various categories of exploration and development expenses are to be deducted in accordance with the terms of the Act as amended by Bill C-11.

Jan 1, 1978