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By Morris J. Viljoen, David R. Young

"The zone of economic interest at H.J. Joel Gold Mine is the VS5/Beatrix Composite Reef, a quartz-pebble conglomerate of Archean age. The reef occurs at the base of the Eldorado Formation, Central Rand Group, of the Witwatersrand Supergroup. At least three stratigraphically distinct conglomerates form this economic zone. In order of deposition these are the Footwall, Beatrix, and the VS5/Beatrix reefs. The Footwall and Beatrix reefs are equated with the Aandenk Formation with transport directions toward the northwest, whereas the VS5lBeatrix Reef is of Eldorado age, with transport directions toward the south. The change in the drainage direction was caused by a major basin-wide tectonic event that occurred prior to the deposition of the Eldorado Formation. The Beatrix Reef was formed in a proximal, braided, fluvial environment by a process of aggrading gravel bars between channelways. The VS5/Beatrix Reef was formed by the desegregation of pre-existing Beatrix Reef with the introduction of new material containing much shale detritus and is seen to have been deposited in a more -distal, braided, fluvial environment, similar to the Beatrix Reef.The average gold concentrations are different for each conglomerate; the Beatrix at 32.1 ppm Au, the Footwall at 24.4 ppm Au, and the VS5/Beatrix at only 12.4 ppm Au. A sedimentary gold concentrating process related to higher energy braid channels was primarily responsible for these high gold grades. Not only the basal unconformity surface, but also, internal degredation surfaces, were prime sites for concentration. An understanding of the spatial distribution of these differing conglomerates and their braid channels forming the economic reef zone is necessary in predicting ore grades for future mining."

Jan 1, 1994

By Suzie Poulin, N. Geoffroy, G. P. Demopoulos

Most metallurgical industries generate toxic waste that must be treated prior to being released to the environment. However, in a lot of cases, the waste materials are poorly characterized or the analytical results are not well interpreted. These shortcomings often result in the development of inefficient industrial procedures, thus causing economic waste and difficulty meeting environmental regulations. Fortunately, a wide range of analytical techniques are available to guide researchers and engineers into making sound process development decisions. In this work, an industrial selenium and mercury removal process is used as an example to illustrate the application of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) coupled with Energy-dispersive X-ray spectroscopy (EDX) and powder X-ray diffraction (PXRD) on solid waste. Furthermore, samples of analytical results are presented and interpreted and the modifications to the industrial process that resulted are explained. Finally, a brief description of the advantages and limitations of the aforementioned analytical techniques is given with an emphasis on industrial solid waste material.

Jan 1, 2011

By S. Gheibi, H. S. B. Duzgun, N. Dadashzadeh

It is widely recognized that there are various uncertainties in the analysis of rock slope stability owing to inadequate information for site characterization and inherent variability and measurement errors in geological and corresponding parameters. Therefore, reliability-based approaches that allow the systematic and quantitative treatment of these uncertainties have become a topic of increasing interest in rock slope engineering. There has been extensive reliability analysis of rock slope stability in the literature. However, all of these analyses are based on the First-Order Reliability Method (FORM). The probability of failure of a rock slope in the First-Order Reliability Method is provided by a linear approximation of the failure function. The FORM is most commonly used because it is efficient; its accuracy, however, deteriorates when the nonlinearity of limit-state function increases. A better approximation of the failure function can establish a more accurate value of the probability of failure. The Second-Order Reliability Method (SORM) overcomes this drawback with a cost of lower efficiency in terms of the number of function calls and computation expenses. Despite considerable studies of the application of the SORM in other engineering fields, a few attempts have been made in the slope stability studies. In this study, a recently published Second-Order Reliability Method with First-Order Efficiency (SORM-FOE) is implemented on a selected rock slope in Amasya, Turkey. The SORM-FOE overcomes the low efficiency of the SORM by decreasing the number of function calls. The probability of failure of both FORM and SORM-FOE are obtained and the results are compared. It is shown that, in high value of failure probability, SORM’s do not significantly affect the analysis and design. However, in very low failure probability, the discrepancy between FORM and SORM-FOE becomes pronounced. It is also shown that, where the second order methods are required, the SORM-FOE is more efficient than the conventional curvature fitting methods in terms of computational costs.

Jan 1, 2015

By Gaston Gendreau

CETTE PRÉSENTATION traitera des différentes phases des opérations de la mine du Mont-Wright depuis ses débuts jusqu'à présent. A une brève description de la géologie du gisement, suivra un exposé des méthodes d'exploitation de la mine et du genre d'équipement utilize.

Jan 1, 1977

The steam-filtration process for dewatering solids involves the application of slightly superheated steam to a filter cake during filtration. The mechanism by which the technique promotes water removal has been deduced from bench-scale experiments on coal and on granular iron ore concentrates. The mechanism, along with some of the applications and limitations of the process, is presented. Introduction I N the steam-filtration process, slightly super-heated steam is applied to the filter cake during filtration to remove more water than can be extracted by conventional filtration. Although this process was developed by Burton for coal filtration (1), it should have far wider applicability; certainly, it could be used to treat any mineral product, because only low-temperature steam is needed and most conventional filtration equipment can be easily adapted to it. As few restrictions apply to this process, however, it is important that its more obvious advantages and disadvantages be appreciated and, especially, that the criteria on which economic evaluations can be based are understood.

Jan 1, 1965

By Georges Houlachi, Akram Alfantazi, Michael Mahon, Maysam Mohammadi

Corrosion resistance of the lead-based anodes directly influences the purity of the final product in the zinc electrowinning process. The anodic MnO2 layer that is electrodeposited on the anodes during this process can protect the anodes against corrosion. Sand-blasted anodes generate a uniform, adherent and shiny MnO2 layer, which gradually blisters and eventually sloughs off after several weeks. In this study, we attempted to develop a new method to stabilize the MnO2 protective layer on the anodes during the electrowinning process by providing suitable nucleation sites for electrodeposition of this layer. MnO2 particles (P80=40µm) were used as seed material for this purpose. Different techniques of galvanostatic and cyclic voltammetry polarizations, scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were employed to investigate the performances of the MnO2-seeded lead anodes. The experimental results showed that growth of the MnO2 layer is influenced by the MnO2 seed particles on the anode surface. The MnO2 layers electrodeposited on the MnO2-seeded lead anodes were uniform and strongly adherent to the substrate. This layer was more stable than those formed on the PbAg anode without MnO2 seeding. This could provide the anode with a higher level of corrosion protection. Moreover, formation of undesirable MnO2 mud in the electrolyte and the rate of manganese consumption were decreased when the MnO2-seeded lead anodes were polarized. These observations could be attributed to the different properties of the electrodeposited MnO2 layer on this anode in comparison with that formed on the PbAg anode.

Jan 1, 2016

By K. D. Watson

"THE Mindamar zinc-lead-copper mine, owned by Mindamar Metals Corporation Limited, is at Stirling in Richmond County, near the south-eastern shore of Cape Breton Island, Nova Scotia (Figure I). It is connected by several roads with the Canadian National railway at Sydney and St. Peters.The deposit is said to have been discovered around 1895 as an outcrop in the bed of Copper brook, but the details are obscure. Not until 1925, when it was optioned by American Cyanamid Company, was it developed underground. Between 1927 and 1938, the 1-nine was operated intermittently by The British Metal Corporation (Canada) Limited, and yielded approximately 200,000 tons of ore averaging about IO per cent zinc, 2 per cent lead, I per cent copper, and small quantities of silver and gold. In December 1950, Dome Exploration (Canada) Limited made an agreement with Mindamar Metaî Corporation Limited, which was exploring the old mine, to assume management and prepare the property for production. Production started in April 1952 with a new mill and a new four-compartment shaft, and between that time and the end of 1954 it has totalled 545,347 tons of ore averaging 5·89 per cent zinc, 1·35 per cent lead, 0·66 per cent copper, 0·032 oz. gold, and 2 151 oz. silver.The Mindamar orebodies are irregular lenses and large veins lying within a wide, almost vertical shear zone of remarkable persistency. The shear zone consists mainly of well-foliated sericite schist derived from siliceous siltstone, and it contains a vast amount of dolomite and magne-site of hydrothermal origin. Most of the ore is extremely fine-grained and some of the high-grade material has a conspicuous thinly layered structure. The metallic minerals, in order of decreasing abundance, are pyrite, sphalerite, chalcopyrite, galena, and tennantite; the gangue minerals, in the same order, are dolomite and magnesite, quartz, sericite, talc, chlorite, barite, albite, and alunite.The geological setting of the deposit is shown in Figure 2. Except along streams and lake shores, almost all of the bedrock is concealed by glacial drift. The group of rocks in which the deposit occurs consists principally of greywacke, siltstone, tuff, brecoia, and Javas, and has been correlated lithologically with the Bourinot group of Middle Cambrian age. A short distance west of the mine, these rocks are in contact along the Stirling fault with conglomerate, arkosic sandstone, and quartzite belonging to the Middle River group of Silurian or Devonian (?) age, which elsewhere in the area overlies the Bourinot group unconformably. The large bodies of granitic rocks in the region, and the large lenticular masses of diorite and quartz diorite associated with them, have been assigned by Weeks (5, pp. 68-69) to the Devonian."

Jan 1, 1949

By K. Negishi, H. Izui, Y. Komiya

"Aluminum has the disadvantage of low strength. In order to obtain the high strength composites, crystals were refined in the composites. Grain refinement was approached at two process points, generating new grains and grain growth. It is important for refinement how to control the grain growth. Spark plasma sintering (SPS) technique and TiB2powder addition prevent grain growth. To investigate effects of strain and additives to the alloy, aluminum powder was sintered at 70 MPa and 80 MPa, changing the content of TiB2additive powder by SPS method. As the results, the crystal grain size was finer in the composite sintered at higher sintering pressure and with larger amount of additive, though over 1.0mass% TiB2addition dissuades grain refining. These grain refinements improve hardness and tensile strength of sintered aluminum alloys.INTRODUCTIONAluminum matrix composites have low density, high specific strength, and low cost. Their applications are growing continuously in the field of automotive and aerospace industries. Recent studies to improve their good mechanical and tribological properties use different ceramic materials such as Al2O3(Das, Munroe, & Bandyopadhyay, 1996; Ashwatha & Anthony Xaviorb, 2014),SiC(Hassani, Bagherpour, & Qods, 2014), B4C(Ehsan, Masoud, Touradj, Amir Hossein, & Ali, 2015),TiC(Ehsan, Ali, Masoud, Kamyar, & Touradj, 2017), and TiB2(Fei & Zhong-Hua, 2013).On the other hand, grain refinement is also an important techniques for improving the properties of aluminum alloys. Finer grains improve the mechanical properties of the alloy. For cast and wrought alloys, addition of grain refiners in molten alloys accelerates generation of nucleus and suppresses grain growth. Al-Ti-B alloy is generally added as grain refiners in the molten aluminum alloys(Easton & Stjohn, 2001). Especially, TiB2has very high melting point, low density, and excellent hardness. Therefore, TiB2was selected as additions into aluminum alloys. Liquids reaction leads to high cost, oxidation, discoloration of molten alloy, and clustering of additive powder as compared with solid reaction such as sintering. However, sintering of aluminum alloy powder with ceramic powders is difficult for oxide layer surface. Recently, we take attention to spark plasma sintering (SPS) as advanced sintering process. SPS process can easily sinter a high quality specimen at a lower sintering temperature and in a shorter time than conventional sintering processes. By SPS process, we have sintered titanium powders that are as difficult to be sintered by any other processes as aluminum powders, and improved mechanical properties by adding hard ceramic powders TiC and TiB(Kamegawa, Izui, Komiya, Kobayashi, & Arimoto, 2015; Sampei, Izui, Komiya, Shigimura, & Suzuki, 2015). Furthermore, it is important to consider not only pure aluminum but alloys for solid-solution or precipitation strengthening. Actually, pure Al does not have enough strength compared with the alloys. Al-Cu alloy and Al-Mg alloy demonstrate adequate strength for industrial and commercial sectors. Al-Mg alloy retains good formability, and has high resistance to corrosion. It is therefore used for many applications. We must consider alloying processes. The most cost effective process is blended elemental technology where alloying elements are added to base powder as elemental or master alloy powder (Smugeresky & Dawson, 1981; Yasue, Radjai, Miwa, & Sakaguchi, 2003; Bolzoni, Esteban, Ruiz-Navas, & Gordo, 2012)."

Jan 1, 2018

By Bert S. Hall

"The purpose of this paper is to review the evidence at hand concerning the earliest centuries of cast iron in Europe, from roughly 1400 A.D. until the second half of the sixteenth century. For the most part it is concerned with the relationship between two technologies which emerged first in China and then later appear in Western lands, gunpowder weapons and iron founding. We should not assume, as I hope to show later in this discussion, that weapons constituted the only product for which the iron founder had any market, but it is clearly true that attempts to produce weapons constituted the most severe technical challenge for the early founder. Firearms appear for the first time in Europe in the 1320s and develop into significant weapons on the field of battle by the end of the century. Theirs is a complex history, subject neither to easy summary treatment nor to simplified models of development. I hope to be able, through the analysis of the evidence concerning cast iron, to show that one important strand in the fabric of gunpowder's history concerns the materials from which cannon could be made. This question is subject to a number of shades of meaning, because ""cannon"" can be made for many purposes under a profusion of different names, and under sharply varying conditions of use. As a result, the question of materials is frequently really a question of competing materials, and involves a complex set of factors, of which production costs and the ultimate safety of the user seem the most important. Judged in this manner cast iron was an important but unsatisfactory metal for weapons purposes until 1543, at which time English founders learned to make iron muzzle-loading cannon which could rival bronze ordnance in most important performance criteria, but which cost much less to produce. With that event, the history of cast iron and the history of weapons entered into the close relationship that persisted until the advent of rifled artillery made of steel in the middle of the nineteenth century."

Jan 1, 1999

By N. Razavinia

Most mining and metallurgical industries produce relatively large quantities of low grade waste heat which they vent, for the most part, to the environment. To date, little is being done to recover some of this heat and transform it from low grade to a high grade energy form such as electricity. A few decades back this was also true of paper, plastics and metals. Recycling was not a prominent activity. Today, we all know that it is and that recycling is a must for sustainable development. To this end, we feel that we are now at that point in time when the recycling of waste heat to electricity must be given serious consideration. By recycling waste heat one can achieve at least one if not two of the following benefits: 1) reduction in the carbon footprint ? by improving the overall energy efficiency of a process, and 2) production of electricity at an economically viable cost. We have developed a process that captures, concentrates and converts (3 C?s) waste heat to electricity. The process comprises 3 distinct interacting units. The first unit captures and concentrates waste heat using heat pipe technology. The second unit converts some of the concentrated heat to mechanical work which can then be readily converted to electricity. This unit is based on the classical piston/cylinder engine arrangement that is widely used by consumers to power systems with compressed air, for example. The third unit of the process dissipates the heat that the engine cannot convert to high grade energy. It also uses heat pipe technology to achieve this. The combination of the 3 units forms a unique system for recycling waste heat. This paper describes the system and it presents some results that show how the system can be made to be economically viable.

Aug 1, 2013

By L. Long

Stirred milling of nickel laterites offers possibilities for improving liberation and selective size reduction of soft nickel-bearing minerals in laterites. Batch grinding tests were performed in a Netzsch LME4 stirred mill on siliceous goethitic (SG), goethitic (G), and saprolitic (SAP) nickel laterite samples (- 2000 ?m particle size) to evaluate the effect of stirrer speed, solid content, water salinity and grinding time. A fine mineral product (-38 µm) was used to evaluate the effect of selective grinding and Ni upgrade. The optimum grinding time for the highest Ni upgrade was 0.25 min, 0.1 min and 0.1 min for the SG, G, and SAP nickel laterite, respectively. A new feed (38-2000 µm) for each nickel laterite sample was prepared for batch grinding tests under the optimum grinding conditions. Upon grinding the 38-2000 µm feed, the - 38 µm product confirmed the effect of selective grinding and nickel upgrade. Size classification followed by stirred milling is a suggested process for Ni upgrade. The best Ni upgrade result was achieved on the SG nickel laterite among the three samples. The Ni grade increased from 0.85% to 1.37%, with 27.8% Ni recovery. Bottle roll leach tests showed that for SG and SAP samples selective grinding had no dramatic effect on Ni extraction due to the slow leach rate of hard mineral particles. Stirred milling of G sample increased the surface area of goethite, resulting in higher Ni extraction. Gravity concentration through a Knelson Concentrator was not effective in the further treatment of the stirred milling products either due to the poor operating conditions or due to the mineralogy characteristics of the feed samples. The energy requirement in the stirred milling was investigated. The first pass of the signature plots study is critical for the purpose of selective grinding, because the best result on selective grinding is achieved in the early stage of the grinding process.

Aug 1, 2013

An optimized long-term mine planning determines the best order of material extraction, so that the Net Present Value (NPV) becomes maximum. In the case of oil sands surface mining, one of the key constraints in NPV maximization is the volume of tailings slurry that will be generated downstream. Specifications of tailings slurry are also important from environmental perspective. Moreover, most of the material that will be used for the reclamation of tailings ponds in later periods is generated in extraction and processing of oil sands. In this paper, an integrated optimization framework is proposed to maximize the NPV of the produced oil sands, with respect to tailings capacity constraints and reclamation material requirements. A mixed integer linear programming (MILP) model is developed to find the optimal solution for long-term mine planning problem. The proposed model is coded in Matlab and has been run using CPLEX for verification. The results for real-case oil sands dataset show that the optimal production schedule meets material requirements for reclamation, tailings volume is within tailings capacity range in all periods and the production schedule follows the predetermined horizontal direction.

Aug 1, 2013

By S. Spigarelli

The creep response of the AE44 magnesium alloy was studied by means of constant load creep tests carried out at 125 and 150°C, obtaining that at the latter temperature the minimum creep rate observed under an applied stress of 100 MPa was two orders of magnitude lower in the investigated alloy than in AM50. The minimum creep rate dependence on applied stress was described by a conventional power-law, e = Aon , where A was a temperature dependent parameter and n was the stress exponent, resulting in a n value close to 30, i.e. by far larger than those observed in commercial alloys with similar Al content. This large difference in creep response was attributed to the precipitation of rare earths (RE) intermetallic phases distributed in the grain boundary zone in form of an almost continuous network of dispersoids that were observed by means of scanning electron microscopy.

Jan 1, 2006

By J. G. Peacey

"Canada has a special place in non-ferrous pyrometallurgy because it is the only country in the western world that is a significant producer of all the major non-ferrous metals; aluminum, copper, lead, magnesium, nickel and zinc. This large non-ferrous pyrometallurgy industry has developed because of Canada's abundant mineral wealth and energy resources. Table I summarizes the number of primary non-ferrous production facilities in Canada and their share of western world production.Production of non-ferrous metals is a mature, capital intensive business and its basic processes have been in use for many years. Nevertheless, these processes have continued to evolve in response to changing needs and external pressures; such as the energy crisis of the early seventies; historically low metal prices in the early eighties and the continuing pressure to reduce plant emissions and improve in-plant working conditions. Canada's major metallurgical companies: Alcan, Cominco, Falconbridge, Inco and Noranda have played a leading role in pioneering new process technology and continue to meet the difficult challenge of keeping their operations competitive in the global metals market. This paper will try to give an overview of the major developments in non-ferrous pyrometallurgy, largely from the Noranda and Canadian perspectives, highlighting the current status of process technology and possible future directions.AluminumCanada has the world's second largest aluminum smelting industry and its capacity has expanded rapidly in recent years with the completion of several large projects in Quebec. The location and capacity of the Canadian aluminum smelters are given in Table 2. All these plants use the Hall-Heroult process, that was invented over a century ago but over the last twenty years considerable improvements have been made to increase productivity, reduce power requirements and emissions.The developments in aluminum cell technology can be illustrated by the experience at Noranda Aluminum. In 1971, Noranda Aluminum started its first pot line using Kaiser's P69 prebake cell, which was considered, at that time, the best available technology. The P69 cell was designed primarily for high productivity, operating at 150 000 amps and high current density to produce just over tonne Al per cell-day. The P69 cell is a simple design, typically operating at about 88070 current efficiency and 15 800 kWh/tonne Al. When Noranda Aluminum decided to expand in 1980, the Alcoa 697 cell was selected as it then represented the most proven, stateof- the-art technology. This cell is similar to that installed at Alcan's new Grande Baie and Laterriere smelters and is designed to operate at 180000 amps and 93070 current efficiency, producing about 25070 more aluminum per pot-day than the P69 cell using about 15070 less power. The 697 cell has a much more sophisticated cell design, with very good balancing of the magnetic field giving a flat metal pad and allowing efficient operation at the higher amperage. Alumina is fed via point feeders that provide an almost continuous feed allowing close control of the alumina level in the bath and the use of low-ratio bath composition, giving much higher current efficiencies."

Jan 1, 1991

By C. J. Sullivan

It is of importance, in prospecting, to distinguish ores of magmatic origin from those derived by the meta-morphism and granitization of source rocks and from those accumulated in certain sedimentary facies. The magmatic ores, which are characterized by their occurrence along fault structures, may be associated with volcanic (including explosive) phenomena. Heat effects are local. The magmatic sequence is well de-fined: kimberlite, with diamond pipes; ijolite, with carbonatites; peridotite, with nickel deposits; norite, with nickel-copper deposits; and diabase-gabbro, with copper-zinc deposits. These deposits are characteristic of Precambrian shields, where a thick sialic crust may rest on basic to ultrabasic magma. The sequence is resumed in the Paleozoic terrains (in a broad sense), with monzonite porphyries and associated copper, copper-gold, and cop-per-lead-zinc deposits.

Jan 1, 1962

By Louis Tellier

SIDBEC commenced detailed planning of major capital expenditures to install integrated steelmaking facilities in 1969. Today, less than IO years later, SIDBEC and its subsidiaries have completed major mining, concentrating, pelletizing, direct reduction ? electric furnace steelmaking and continuous casting plants. The total cost of these projects was almost 1 billion dollars. The philosophy behind the project planning and the evolution of management control are explained. These extensive projects were undertaken during a period of exceptional inflation and a disturbed labour climate, but were nevertheless completed with only modest overruns, with good control of timetables and with exceptionally good start-up performance. Project planning, relations with consulting engineers, introduction of new technology, purchasing and field management and cost control are discussed.

Jan 1, 1979

By P. Cielo

"Nondestructive inspection is an important quality control tool in the material processing industry. Being nondestructive, such a control may be applied to the whole production, as long as the available techniques are fast and easily automated. Ideally, nondestructive testing (NDT) methods should operate in a noncontact configuration in order to be deployable on-line with minimum perturbation of the production process.After a short introduction to the most common NDT techniques, with particular emphasis on ultrasonic, radiographic and electromagnetic methods, a few new approaches which are under development at the Industrial Materials Research Institute, (Boucherville, Quebec), are reviewed. Noncontact techniques such as laser ultrasound, thermoelastic and thermographic methodologies will be described, and their applications to materials of industrial interest will be discussed."

Jan 1, 1989

By C. V. Corless

THE origin of various types and groups of ore deposits was some years ago a subject of much controversy. To this statement the copper-nickel deposits near Sudbury afforded no exception. Not since the Report of the Ontario Nickel Commission, in 1917, has there been any serious discussion of the origin of this very important group. This may be because, from the opening-up of Murray mine by the British America Nickel Corporation until the recent work at Frood mine, no new ore-body of importance has been developed in the district. The controversy fifteen or twenty years ago between those who favoured the theory of magmatic segregation, among whom Dr. A. P. Coleman was the leading exponent, and those who considered that most, if not all of the Sudbury deposits could more satisfactorily be accounted for by the theory of replacement, will be remembered by many members of the Institute. Perhaps, as too often happens in controversial discussion, each side tended to overemphasize the importance of those geological phenomena which seemed to be most easily accounted for by the theory it favoured. A more balanced view would perhaps admit that replacement was probably predominant in the formation of most of the offset deposits, and magmatic segregation in that of most of the marginal deposits . But there is danger in generalization. Each body of ore should be studied by itself, and no general conclusion of this kind should be allowed to warp the judgment in making such a study.

Jan 1, 1929

By Z. Trojanová

The deformation behaviour of ternary magnesium alloys AJ (Mg-Al-Sr) and AX (Mg-Al-Ca) were investigated in tension as well as compression tests. The samples were deformed at temperatures between 20 and 300 °C and at an initial strain rate of the order 10-4 s 1. The flow stress decreases with increasing temperature. The macroscopic work hardening rate decreases with increasing flow stress and temperature. The stress and temperature dependence of the work hardening rate is a result of the hardening and softening processes. Stress relaxation experiments were performed in order to reveal features of the thermally activated dislocation motion. Internal and effective stress components of the applied stress were estimated. A decrease in the internal stress was observed at elevated temperatures, which indicates recovery process (-es). A more detailed analysis of the estimated values of the activation volume and activation energy helped to interpret the thermally activated processes during plastic deformation. It is concluded that the deformation behaviour of the alloys depends on the activity of non-basal slip that is strongly influenced by temperature.

Jan 1, 2007

By G. J. Simandl, H. -L. Jacob, S. Paradis, G. Valiquette

"Nos travaux de terrain dans le Grenville, effectués dans le cadre d'un projet d'inventaire des gîtes de wollastonite, ont démontré qu'il existe un secteur exceptionnellement favorable à l’exploration pour la wollastonite. Ce secteur s'étend de la municipalité de Grenville jusqu'au pare du Mont-Tremblant (nord de St-Jovite). D'autres secteurs favorables a 'exploration pour la wollastonite ont été délimités dans les regions du Lac-Saint-Jean, de Shawinigan et de la Gatineau. Neuf categories litho-structurales de gites de wollastonite furent identifiées. L'importance d'un système ou vert pour la formation des gîtes de hautes teneurs fut établie. Un guide de prospection pour la wollastonite propre à la province tectonique de Grenville fut développé. Plusieurs des indices sont prometteurs et mériteraient des travaux de raise en valeur afin de determiner s'ils représentent une source de wollastonite exploitable à profit. Lac-Saint-Jean, Shawinigan and Gatineau areas. Deposits may be classified into nine categories depending on their relationship to intrusive rocks, discordant or concordant contacts with the host rocks, morphology, and major structural controls. Deposits consist mainly of wollastonite, calcite and clinopyroxene. They may contain one or several of the following minerals: feldspar, scapolite, quartz, titanite sulphides, zoisite, clinozoisite, garnet, idocrase and prehnite. Wollastonite content may reach over 70%. Some deposits are associated with graphite veins. Better understanding of the geology, combined with the proposed classification provides new exploration guide for wollastonite. Several deposits have grades of economic interest. Further work is needed to determine if any of these deposits can be exploited for profit."

Jan 1, 1990