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By L. H. Thorleifson

Demand for both gem and industrial diamonds is very strong. Synthetic production supplies industrial uses, but synthetic gems remain inferior and expensive, so the large gem market is supplied by mining. Several major mines have been depleted, and the market is receptive to new sources of high quality gems. Canada's Precambrian terrane, extending across the Canadian Shield and under the Phanerozoic cover of the Plains and Hudson Bay, has excellent potential for diamonds, but exploration conditions are difficult due to recent glaciation. Early world exploration relying on recognition of diamond in alluvial sediments was adequate to launch pre- 1900 production from India, Brazil, and Africa. Exploration success in Canada, as was the case in Russia and other more recently discovered sources, however, had to await large investments in effort supported by advanced science and technology. Canadian exploration in many ways is similar to that in other regions, relying on analysis of tectonics, indicator minerals, geophysical surveys, and multiple stages of drilling and sampling. Very different from other regions, however, is Canada's surficial environment, in which recent glaciation has caused fresh indicator minerals to be transported hundreds of km. Exploration accelerated in Canada after 1960, first in Ontario and the Arctic Islands, then in Saskatchewan in 1988, and most importantly after the Chuck Fipke - Stew Blusson discovery at Lac de Gras, Northwest Territories, in 1991 that led to the billion-dollar BHP - Dia Met Ekati Mine that opened in 1998. In 2003, production from Ekati will be supplemented by that from the similar and nearby Diavik Mine of Rio Tinto and Aber. These mines will bring Canadian output to over 10% of world supply, and will position Canada with Botswana and Russia as world leaders in production of high quality gem diamonds. There could be other mines as well, as sites across the Arctic and in the south from Alberta to Québec are being explored by an array of companies, including De Beers, other majors, and several juniors.

May 1, 2003

By J. W. Spyker, D. H. Filson, W. H. W. Husband

"Large deposits of sodium sulphate exist in southern Saskatchewan in the brines or muddy crystal beds of alkali Jakes. Currently, more than 300,000 tons per year of sodium sulphate are produced from these lakes and sold as salt cake to the paper industry. Most of the production is obtained from the brines of a limited number of Jakes.The Saskatchewan Research Council was requested to develop a process for recovering sodium sulphate from the muddy crystal beds so that this type of deposit could be exploited in the future. A flowsheet was developed with the aid of phase diagram data and the process was studied on a pilot-plant scale using raw material from three different lakes. Satisfactory yields and product purities were obtained in all cases, and an economic analysis indicated that a 100,000-ton-per-year sodium sulphate plant could produce salt cake at a cost of $12.26 per ton for a rate of return upon investment of 16 per cent at current market prices."

Jan 1, 1966

By R. Wirth, B. Orberger, C. Wagner, A. Tudryn, B. Baptiste, S. Miska, Université Paris-Sud

Banded iron formations (BIFs) comprise complex textures and mineralogy, which result from fluid-rock interactions related to high and low temperature alteration. The initial iron oxy hydroxide mineralogy and associated phases such as carbonates, quartz, apatite and phyllosilicates were transformed leading to an upgrading of these BIFs into the world’s largest source of iron ore. In low-grade BIFs, a large part of the iron is related to micro- and nano- metric iron-bearing inclusions within micrometric quartz and/or carbonates (mainly dolomite). We studied laminated jaspilitic BIF samples from a drill core containing 26.71 wt.% total iron, 0.2 wt.% SiO2, 0.32 wt.% MnO, 15.46 wt.% MgO, 22.32 wt.% CaO, 0.09 wt.% P2O5, < 0.05 wt.% Al2O3, 0.15 wt.% H2O and 34.08 wt.% CO2 (Aguas Claras Mine, Quadrilatero Ferrifero, Brazil). Bright rose coloured dolomite and quartz bands alternate with massive specular hematite bands. Raman spectroscopy, X-ray diffraction and FIB-TEM analyses reveal that the micro- and nanometric inclusions in dolomite are mainly hematite and minor goethite, partly occurring as clusters in voids. Curie Balance analyses were carried out at different heating steps and temperatures on whole rock samples and a synthetic mix of decarbonated sample and pure dolomite. X-ray diffraction on the products of the heating experiments shows that that hematite is stable and new phases: magnesioferrite (MgFe2O4), lime (CaO), periclase (MgO), portlandite (Ca(OH)2) and srebrodoskite (Ca2Fe2O5) were formed between 680°C and 920°C. These finding gives hints to optimizing the beneficiation process, as the presence of hydroxyl ions bearing goethite micro- and nanoinclusions lowers the sintering temperature. Prior separation of coarse hematite and barren dolomite and quartz, followed by lower temperature sintering of the inclusionbearing dolomite/quartz leads to transformations into phases with higher magnetic susceptibilities (such as hematite and magnesioferrite). The entire Fe and Fe/Mg oxide feed (the priorly separated fraction added to the sintered fraction) can then pass through wet-high intensity magnetic separation after crushing.

Jan 1, 2016

By G. Lodewijks

This paper explores the savings that can be achieved in the energy consumption of belt conveyors used in mines by changing the conveyor components, the operational parameters of the system or the belt properties. First the concept of energy savings is introduced by looking at the energy consumption of belt conveyors from a theoretical point of view. Also methods for the calculation of the power consumption of a belt conveyor and the associated emissions are presented. Two case studies are presented in which the effects of the change of the operational parameters of the system, in this case the belt speed, and the belt properties, in this case the application of aramid products in the belt, are presented.

Aug 1, 2013

By J .. R. Brown, G. Deschenes

X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD) and Electron Probe Micro-Analysis (EPMA) were used to characterize chemically the gold complex adsorbed on activatedcarbon from a solution containing 102mglL Au and 0.5 giL thiourea. This paper also considers the gold chloride and the gold cyanide systems. The results indicate gold is adsorbed on activated carbon from the thiourea solution as the gold (I) thiourea complex, i.e. Au [CS (NH) 2];&apos; Other gold species such as metallic gold were not detected on the carbon support. These results also suggest the elution of the gold (I) thiourea complex can be performed with high recovery.

Jan 1, 1993

By Vahid Faghihi

SatraPM is a web-based software package, aiming to help project managers to easily handle their construction projects via internet. This software is capable of handling all projects of an organization, in which all projects can be defined in EPS the same as users in OBS. A 3D accessing module links EPS, OBS and inherent functions in order to provide a secure environment for the data to be processed throughout the system. This paper intends to take a deeper look at capabilities of SatraPM in helping project managers to keep track of and control their construction projects as well as its potential future features.

Aug 1, 2013

By Nicholas C. Williams

This paper presents the development of a demand reduction and responsive strategy capable of reducing the electrical power demand, particularly during peak conditions. The work presented includes a case study of a UK colliery. Areas explained are the equipment installation at the mine; the development of the demand reduction strategy including the load profile database and prediction optimisation model. Some live production data from the power meter installation at the mine is also presented.

Aug 1, 2013

By Franz Xaver Spachtholz

K+S Potash Canada GP (KSPC) is part of the K+S Group, one of the world&apos;s leading suppliers of standard and speciality fertilizers and the world?s leading salt producer. Globally, the K+S Group employs more than 14,000 people. The K+S share ? the only commodities stock on the German DAX index ? is listed on all German stock exchanges. Legacy, K+S Group?s most recent project, is a greenfield solution potash mine and production plant in the south of the Canadian province of Saskatchewan. Therefore K+S will invest 4.1 billion CAD. With the expected commissioning in summer 2016 the company projects to reach the two-million-tonnesmark of production capacity at the new location at the end of 2017. The gradual extension of the annual capacity to 2.86 million tonnes of potash products will occur afterwards. The Legacy Project will be Saskatchewan?s first new potash mine in nearly 40 years. It is one of the world?s most economically attractive potash projects. The project will contribute to Saskatchewan?s growth through employment, tax revenues, utilities, and local partnerships. Located in the southern part of Saskatchewan?s potash belt, the deposit is too deep to be mined conventionally due to rock mechanics and high temperatures. Legacy will therefore be a solution mine. Proximity to the urban centers of Regina and Moose Jaw is imperative, with their workforces and economy, as well as access to highways, railway carriers and, most importantly in the prairies, water. With this unique project setting and mining technique, we are convinced that Legacy will be one of the most efficient, economic, sustainable and safe potash facilities in the world.

Aug 1, 2013

By J. Laganiere

A considerable part of the sulphuric acid requirements of the Aluminum Company of Canada&apos;s Arvida smelter comes from the burning of 180-200 tons per day of zinc &apos;"&apos;sulphide concentrates in a 22-ft.-diam-eter fluidized bed roaster. The plant and its operation were fully de-scribed in a publication that appeared about ten year ago (1). A simplified flowsheet of the roasting and gas-cleaning sections of the plant is given in Figure 1. The wet zinc sulphide concentrates are un-loaded into a pug mixer, by means of a Pay loader, and mixed with water in a mixing tank to make a slurry of 80 per cent solids. The slurry is transferred to a .feed tank and then introduced into the roaster at a point four feet above the constriction plate, which is the height of the settled bed of zinc calcines. The roasting temperature is con-

Jan 1, 1963

By Bahaa Hussein

Considerable number of methods and procedures has been introduced for trending and progress reporting of engineering, procurement and construction projects. This paper introduces a novel method, designed to augment the set of indices for measuring schedule performance. The concept behind the developed method is to provide early warning by dynamically evaluating the schedule cumulative impact of construction projects. The proposed method is designed to highlight the gradual deterioration in schedule status resulting in a cumulative impact due to the aggregation of small delays encountered during the execution of non-critical activities, and can be used as an add-on utility to existing software systems that perform CPM scheduling. The proposed method is based on a developed formulation for quantification of the Schedule Compression Index, which takes into consideration the remaining project activities durations. The index is developed based on periodic comparisons of ?Current Schedules? and the project ?Baseline Schedule? using the summation of the remaining activities durations. A numerical example is presented to demonstrate the application and capabilities of the developed method. It is expected that the developed index together with other schedule performance indices would be of value to decision makers and members of project teams.

Aug 1, 2013

"Yara Siilinjärvi in Finland is the Western Europe's only apatite mine. Annually it produces one million tons of apatite concentrate, which creates 10 million tons of tailings. At the beginning of 2017, Yara replaced their conventional TSF with a new tailings treatment plant, which increased the solids content of the slurry from 45–48% to 66–68%, making it possible to deposit as a paste. This extended the life-span of the current TSF from 2020 to 2035. This paper presents the storyline of the Yara paste plant project. The project began with laboratory testing and then progressed to pilot-scale thickening and beaching trials. After successful pilot trials, the final process design was implemented. Process automation played a key role in the project. An advanced control system is needed to maintain process stability and the desired operation point in various operational circumstances. Since commissioning the paste plant has been running consistently with an underflow solids content of 66-68%, with average beach slope angles of 3.5 degrees in the tailings disposal area. Robust thickener operation also leads to the trouble-free high-density pumping and high availability of the plan. During first year of operation the plant’s availability has been very good, over 97%, and currently, the plant is operated remotely from the main concentrator plant.INTRODUCTION The Yara Siilinjärvi Plant is owned by Yara International, a Norwegian fertiliser company. Yara Siilinjärvi is Western Europe's only apatite mine, and it primarily produces apatite concentrate for its Siilinjärvi phosphoric acid plant. A portion of the concentrate is also dried and shipped to other Yara fertiliser plants. The site annually produces one million tons of apatite concentrate, which creates approximately 10 million tons of tailings. Extending the lifespan of the 1150-hectare tailings storage facility has been studied in Siilinjärvi for a long time. The aim has been to use the same tailings area footprint, without any new land purchases or major dam increases. An important part of the process has been to study the possibilities for using new technologies, especially thickened tailings technology (Ruhanen, 2014)."

Jan 1, 2019

By Thomas S. Falk, Nils G. Lindberg

The first industrial COBO (Cold Bound) pelletizing plant began operation in May 1975 at Trollhiittan, Swede n. A technical description of the process, together with operational experience with the plant, forms the basis of this paper.

Jan 1, 1976

By I. Le May

"The assessment of integrity in plants is discussed, together with the codes that are being developed for in service evaluation of engineering fitness for service. The use of Risk Based Inspection is described and some examples are provided of the evaluation of in service components in which flaws have been detected. An example of the assessment of the structure of a mine processing facility is described, and application of Risk Based Inspection and plant assessment procedures to mines is discussed. Periodic assessment of large plants and components to determine their integrity for continued safe operation is becoming a more accepted approach than formerly when regular shutdowns were the normal practice. This is on the way to becoming the preferred procedure for petrochemical plants and power generating plants, and the same philosophy is appropriate for many mining operations. Both the American Petroleum Institute (API) and the American Society of Mechanical Engineers (ASME) have committees developing codes for the continued operation of equipment as distinct from the existing design codes. The philosophy is one of risk-based inspection, which can be on a purely qualitative basis or more quantitatively based.The purpose is to reduce the inspection of unnecessary and non-critical items and to concentrate on the most critical components, reducing costs and downtime and increasing safety. The approach differs from that considered by many maintenance engineers, in that defects that are identified during an integrity evaluation do not automatically cause a component or structure to be condemned or require that repairs are made right away. The seriousness of the defect must be considered and the safe operating life can be estimated before it becomes necessary to replace or repair the unit or component. This is no different from what is done today with passenger aircraft and, to an increasing extent, with pressure vessels, reactor vessels and similar components in the petrochemical and power generating industries."

Jan 1, 1998

By William W. Shilts

"In carrying out a geotechnical survey of a proposed gas pipeline route from the Arctic Islands south to Longlac, Ontario, the Polar Gas Consortium contracted the drilling of several hundred 2- to 2D-m-deep boreholes in drift and bedrock. Samples from these holes were made available to the Geological Survey of Canada, where they were subjected to stratigraphic and trace-element geochemical analyses. The geochemical characteristics of the clay and sand-sized heavy mineral fractions of till samples from these boreholes have been summarized in a series of geochemical profiles.From the proposed pipeline terminus at Longlac northward to the vicinity of God&apos;s River in Manitoba, tills contain significant amounts of Paleozoic carbonate rocks and Proterozoic sedimentary rocks derived from the Hudson Bay basin and lowlands. Within this section, two sites were enriched in base metals, indicating the possibility of local mineralization of possible economic interest.From God&apos;s River northward to Seal River, Manitoba, no evidence of local mineralization was noted. The heavy mineral fractions of the tills are universally enriched in Mn-rich siderite thought to originate on or in the Paleozoic section of the Hudson Bay lowlands.From Seal River northward to Thelon River, near Baker Lake, tills contain only components originating west of the Hudson Bay sedimentary basin. Near the Keewatin-Manitoba border, all till is enriched in uranium, which probably originates in the ""young"" porphyritic granites underlying much of the region, and produces a distinctive airborne radiometric anomaly.At the Thelon River, multiple till sections are variously enriched in Cr, Ni, U, Cu and Mo in the vicinity of a distinctive aeromagnetic anomaly.From Thelon River northward, several coincident zones of chromium and uranium enrichment are found where the line of boreholes crosses east-west-striking belts of volcanic, ultramafic and sedimentary rocks of the Prince Albert Group.The results of this study indicate that till tends to have characteristic element associations or concentrations over each of several broad regions along the pipeline route. These are related both to large-scale bedrock associations and to largescale effects of glacial dispersal. In addition, the samples, collected more or less at random with respect to local bedrock geology, have intersected several small-scale geochemical anomalies that appear to be related to zones of mineralization of possible economic interest."

Jan 1, 1980

By P. K. Kaiser, D. D. Tannant

"A support system for large ground convergence conditions or burst-prone ground must contain holding elements (rockbolts, cable bolts, etc.) that are strong yet capable of sustaining large deformations, i.e., they must absorb as much energy as possible. Steel wire rope anchored in a borehole by a friction bolt provides these desired yield characteristics if the frictional anchorage is placed deep enough into the rockmass, i.e., in non-yielding rock or beyond the expected depth of rock ejected during a rockburst. Pull-out tests were conducted on wire ropes anchored by inflated Swellex bolts to assess the feasibility of this support concept. The test results demonstrate that a Swellex bolt generates a frictional anchorage that allows the wire rope to slide at high loads and to absorb significantly more energy than either a Swellex bolt alone, or a cement-grouted cable.The rope/friction bolt combination can be engineered to provide the desired energy absorption and allowable deformation by varying the installed lengths of the friction bolt and the rope. For yielding rope support, the contact length between the rope and Swellex bolt must be short enough to ensure that the rope can slip well before its tensile capacity is reached. A safe maximum overlap length is about one metre for the wire rope used in this testing. When used as support in the backs of drifts, a swaged button on the ropes end must be used to ultimately mobilize the full rope capacity thereby protecting against gravity-driven falls of ground."

Jan 1, 1995

By A. Oja, M. Lahtinen, P. Salonen, B. Saxen

Most of the secondary and low grade zinc raw materials cannot be treated successfully by either conventional roasting - leaching - electrowinning (RLE) process or even by atmospheric direct leaching process. The problems arising especially from high impurity content of these raw materials can be effectively solved by implementation of the solvent extraction process. The utilization of solvent extraction process has been demonstrated by Outotec with raw materials like Waelz oxide, crude zinc oxide and zinc containing concentrator tailings. Based on batch and continuous test work it has been shown that SHG quality zinc can be produced even from the lowest grade raw materials. Impurity control in the solvent extraction process has been examined. The solvent extraction process is the key feature of the whole zinc plant for such raw materials. However, design of the entire zinc process including neutralization and bleed treatment is important for optimization of investment and operation costs of the plant. Very careful evaluation of the zinc process with modern simulation tools is essential. The optimized Outotec zinc process ensures a sustainable and profitable process containing minimal effluent and requiring little residue treatment.

Jan 1, 2014

By Robert Marchand

_ North-western Quebec _ Bousquet mining district _ 21 M oz mining camp _ 100,000 t/yr (400 t/d) _ Shrinkage : 52 % _ Longhole : 40% _ Development : 8% _ 5 days/week _ 120 employees _Discovered in 1936. _12 changes of ownership. _Exploration & development : 1987 _Commercial production : 1990 _Shaft deepening : 1995 _Internal shaft : 1999

Oct 1, 2001

By L. H. Rajala, K. H. Singh

"This paper presents the results of a detailed feasibility study carried out to investigate whether a low-grade deep underground mine of Falconbridge Nickel Mines Ltd., closed since 1975, could be made more productive and profitable by the introduction of new mining technology. For this purpose, recent advances in mine design and development concepts, larger and better designed machines, such as hydraulic drills, high-pressure down-the-hole machines, LHDs, new blasting concepts, more efficient and improved stoping methods, and ground control technology were considered. Technical and economic analyses incorporated the latest computer-based techniques. The mine was reopened in 1979 and the paper concludes with an assessment of actual progress and performance compared with that planned and forecast.IntroductionThe East Mine orebody, located between the Falconbridge Mine and Inco&apos;s Cryderman Mine in the Sudbury District of Ontario, has been in production since 1956. From 1956 to 1978, about 5.6 million tons of ore had been mined from this ore zone. The ore body is low grade and was developed as a cut-and-fill operation. Due to high operating costs, the mine has been shut down several times during economic downturns. The latest closure was in 1975 due to a lower demand for metal.In 1978, investigations were initiated to assess the economic and technical feasibility of mining this ore using new developments in mining technology. In this study, consideration was given to the application of bulk mining methods with a potential for higher productivity, trackless development utilizing efficient LHD machines and hydraulic drills, new blasting and fragmentation concepts, and new ground control technology. Advanced computer techniques, such as finite element, for mine design and rate of return with discounted cash flow analyses for the economic comparison- of various mining options were utilized for a rapid and comprehensive assessment during the feasibility stage."

Jan 1, 1981

By A. Dubé

Introduction It is common experience that on re-heating a fully martensitic steel below the Ac, point, a softer and tougher structure is formed as the tempering temperature is raised. The mechanism of tempering of plain carbon and low-alloy steels has been the subject of many investigations. In a very comprehensive study, Cohen and associates have recently established three different tempering stages, the last of which reaches completion at about 700°F., with heating rates of 5°F. per minute. This latter stage has been established ta be the carbide-forming stage, so that the steel consists of a mixture of ferrite and carbide, which are the metastable equilibrium phases. Any subsequent changes which take place at higher temperatures below the Ac, point in the absence of graphitization or carbide lattice conversion normally consist of agglomeration of the carbide particles. This naturally results in the softening of the steel. However, in many cases the Ac, point, as determined by dilatometry, thermal analysis, etc., only gives a rough estimate of the temperature where the reaction, ferrite plus carbides to austenite, is initiated. This appears to be especially true in the case of alloy steels in which three phases can co-exist in certain temperature ranges. Bain has given data on the three-phase equilibrium in both manganese and nickel steels. In these steels, the formation of austenite at temperatures just above the AeIL apparently involves the diffusion of the alloying elements to the first pools of austenite, thereby making the process very sluggish. As a consequence, the critical Ac points determined by ordinary methods at normal rates of heating can be quite distant from the true equilibrium Ae temperatures.

Jan 1, 1946

By T. Ouellet, F. Chiesa, J. Carignan, D. Levasseur

Common practice for the preparation of permanent mold for aluminum casting is to coat the mold with a ceramic suspension to obtain a chemically stable interface with the aluminum melt. This practice serves two purposes: first, it helps the thermal regulation of the mold and second, it prolongs its life. The possibility of increasing the coating durability by applying it by thermal spray is appealing. Plasma spray of zirconium oxide based coatings was performed on H13 tool steel to study the coating’s thermal fatigue resistance. A unique dip test setup was used to characterize the thermal fatigue resistance of the coatings and of bare H13 steel. Observations of the failure mechanism bring an insight on the requirements of the coating to maximize its durability.

Jan 1, 2014