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By Jeremy P. Richards

Key inputs are volatiles and heat: Slab dehydration: Breakdown of amphibole and serpentine in hydrated oceanic crust releases fluids into mantle wedge, causing metasomatism.

May 1, 2008

By Nordau R. Goodman

T-he Ojibway Salt Mine near Windsor, Ontario, produces almost two million tonnes of97% pure rock salt annually. The salt is mined from the middle F horizon of the Silurian Salina Formation. The salt beds have a gentle dip into the Michigan depositional basin. There is no evidence of deformation. The rock salt is buff coloured and has a number of thin carbonateanhydrire bands. Secondary salt crysrallization occurs throughout the mine.

Jan 1, 1984

By J. A. H. Church

MR. J. A. H. CHURCH: The salient feature would seem to be that the thickness of the seam, in our coals at any rate, is the main factor in predisposition to spontaneous ignition. The evidence, incomplete it must be admitted, in the Saskatchewan and British Columbia fields, and complete in the Alberta field to my mind, shows this up very strongly. The German report on the upper Silesian coal fields definitely fixes the critical thickness at 13 feet, the British report goes far beyond this figure by stating that liability to ignition increases with the thickness of the seam over four feet. Before discussing the Alberta fires it would be well to note an error on page 12 -the probable cause of the fire in the Frank Mine should read "Spontaneous near fault. Heating first discovered 1909". Of the six fires attributed to spontaneous ignition all the seams were identical or in excess of the critical thickness mentioned in the German report. If there be any reason in the foregoing it is high time some forethought were taken to adopt some definite system of laying out the workings of such seams not so much on the outcrop districts as with a view to the future operation to the dip. Seams approaching 13 feet in thickness which to date have shown no disposition towards heating during the extraction of the outcrop areas may well cause infinite trouble or indeed total loss when the ventilating pressures increase as increase they must to the dip. This state of affairs can be combatted only by the adoption of a correct system of working and the provision of numerous airways of as large an area as may be compatible with the physical characteristics of the particular seam.

Jan 1, 1923

By R. Ichimura

This paper summarizes the results of a five-year project, which aimed at improving the current method to process the arsenic-bearing smelter dust of El Teniente. This project, which was started in 2001, was carried out jointly by JOGMEC (Japan Oil, Gas and Metals National Corporation) and CIMM (Centro de Investigación Minera y Metalurgica, Chile), and was financially supported by the Japanese and the Chilean governments. In the new process, the smelter dust is leached with sulfuric acid to dissolve arsenic, which is subsequently precipitated as crystalline ferric arsenate (scorodite) at ambient pressure by controlling the crystallization and crystal growing stage. As a result, a stable form of ferric arsenate is obtained, which passes the U.S. E.P.A. TCLP limit of 5 mg/L As. Copper and zinc are subsequently recovered from the arsenic-free solution. The copper product can be fed into the main copper production circuit at the Las Ventanas Smelter and Refinery, whereas zinc is recovered as a marketable product. A demonstration plant was installed and operated at CODELCO's Las Ventanas Smelter and Refinery. The basic and detailed engineering design was prepared by Mitsui Mining and Smelting Co. Ltd (MMS) on the basis of a joint study done by JOGMEC, CIMM and CODELCO's Las Ventanas Division.

Jan 1, 2007

By C. F. Hews, P. N. Calder

"MIROC and The Mining Industry The Mining Industry Research Organization of Canada (MIROC), incorporated in 1975, is a non-profit organization sponsored by member companies from within the Canadian mining industry. The Canadian mining industry is a world leader in technological development and in organizational and human resources development. A prime objective within the industry is to retain this leadership and also improve its competitive position worldwide.MIROC is dedicated to support the objectives of its member companies and their common interest, and the objectives of the industry. In this context: MIROC's mission is to encourage the formulation of ideas to improve mining technology and methods by any source, and to foster the development and testing of promising initiatives in progressive steps from the early stages of conceptual and feasibility research through manufacture to delivery of new technology to the mining industry. In so doing MIROC plays an important role in the development of individuals skilled in mining research. Management ApproachMIROC's research program is driven by member companies who have interests throughout Canada. The board of directors approve projects that are acceptable to its members. While MIROC's basic research funding is provided by its member companies, about 30% of its annual research budget is now derived from royalties generated from previous research activities."

Jan 1, 1994

By Enrique I. Acuña

Creighton Mine is part of the mining history of Sudbury with more than 100 years of operation. Currently the deeper levels of the mine are reaching the 8000 ft level without implementation of mechanical refrigeration system as a result of the use of the Natural Heat Exchange Area (NHEA) over the past decades. The NHEA of Creighton Mine is part of an old block caving area divided into 4 blocks of trenches that were used to extract the ore. Currently, it is used year round to condition the outside temperature before the airflow enters the fresh air system of the mine. As the mine is progressing deeper, underground temperatures in the lower levels are starting to approach the limit of Vale?s guidelines for working in heat. This paper presents the study developed to improve the management of the NHEA to obtain cooler temperatures at the intake of the ventilation system and outlines the impact to the mine in terms of the additional level(s) that could be operated underground without the use of mechanical refrigeration. This is another of the efforts currently under development for energy conservation and to reduce the capital and operational costs of Creighton Mine while extending the expected life of the mine.

Oct 1, 2010

By Rod Maclean, George Stewart

"This paper covers the planning, development, and mining of an underground pillar complex using a bulk mining method. To achieve the long-term goal of continually improving our operating processes, all cut-and-fill and undercut-and-fill workplaces at Thompson Mine have been evaluated for their conversion potential to the bulk method referred to as VerticalBlock Mining (V.B.M.).Since December 1979, conversion has occurred to the extent where 80% of the ore hoisted is mined using Vertical Block Mining (V.B.M.).Productivity and profitability have been substantially improved by converting to this bulk method, especially in pillar areas.IntroductionThompson Mine is a 6000 ton per day underground nickel mine located 3 miles outside the City of Thompson, 400 air miles north of Winnipeg . The mine has two shafts, T-l and T-3 (Fig. 1). The T-l shaft is 4427 feet deep with the deepest mining taking place on 4000 level. The T-3 shaft, which is the area of this presentation, extends to a depth of 2607 ft with the deepest operating level at 2400 ft. The two shafts, some 10 000 ft apart, are connected underground on numerous levels. The ore mined at T-3 is trammed on 2400 level to the T-I main ore pass and hoisted through the T-l shaft. Eight hundred and fifty thousand cubic feet of fresh air per minute ventilates the mine.The 1400 level 310 pillar complex is located in the T-3 mine area. There are six rib pillars, two crown pillars and one main pillar (boundary pillar between cut-and-fill stopes) within the complex (Fig. 2). The majority of the ore in this area has been mined using mechanized cut-and-fill techniques .Undercut-and-fill mining was the method originally planned to recover these pillars. It is slow, labour-intensive, and requires extensive use of timber during the mining cycle. The extraction drifts in the area are heavily timbered due to their proximity to the ore and the age of the facilities. Increasing drift maintenance costs and the successful mining of two main pillars with V.8.M. techniques provided the stimulus to review the mining plans for this area."

Jan 1, 1988

By W. J. D. Stone

"INTRODUCTION Over the past decade, a number of publications have described the advances in High Intensity Wet Magnetic Separation. A number of significant, but small capacity installations were made and are successfully operating. These were followed some three years ago by larger installations treating ilmenite gravity concentrates; at least one machine treating 25 tons per hour of new feed was installed and is successfully operating.However, this still did not result in general acceptance that High Intensity Wet Magnetic Separation could be applied on a large scale. Neither did it dispel the feeling that High Intensity Wet Magnetic Separation was ""expensive"" and hence, confined to small scale – high value applications suchas the cleaning of tin concentrates. In addition, there is the usual reluctance of being the ""guinea pig"" which has resulted in waiting to see ""someone else"" make the first large installation decision. Such a decision and installation has now been made.Therefore, the purpose of this paper is to show that High Intensity Wet Magnetic Separation has been commercially accepted on a large scale and to show its general application to the base metal mineral industry.Examples are confined to a few specifics due to the large volume of preliminary test data that is available. The art has now reached the stage where much of the preliminary work should be taken through to serious evaluation."

Jan 1, 1971

By Nima Nabavi

Shovels and excavators have significant blind spots due to their large sizes, increasing the chances of collision with other surrounding equipment such as haul trucks, loaders, and dozers. While a camera surveillance system is very useful in preventing collision, it can benefit from two additional features: (i) the ability to display the distance of the closest object within the view, and more importantly (ii) the ability to warn the operator if objects are getting too close. After a comparison between few different technologies, it is explained how these features can be provided by integrating rugged pulsar radar sensors with a camera system. The specific radar technology is already field proven in the harsh mining environments. Motion Metrics International Corp. has developed this exact product, which combines its 4-camera surveillance system (ViewMetricsTM) with a series of rugged radar sensor elements, named ViewMetricsTM-Radar. The radar system employs intelligent CAN bus communication to reduce wiring, hence improving hardware reliability with built-in troubleshooting features. A USB connection is the only hardware bridge between the radar sensors and the embedded computer. As such, an existing ViewMetricsTM system can be easily upgraded to ViewMetricsTM-Radar. As addition of new interfaces to the cab could result in operator distraction, this paper explains how ViewMetricsTM-Radar reduces distraction compared to other radar collision prevention systems.

Oct 1, 2009

By G. A. Maki, P. J. Fullman, R. G. Roden

"In October 1984, Rocanville Division began using a stacking system to handle potash mill tailings. Previous to this date, mill tailings were slurried to the top of the tailings pile and allowed to debrine while flowing down the pile. With the new stacking system, slurried tailings are fed to mobile stackers. The stackers consist of cyclone packs to debrine the tailings and drag conveyors with screw discharges to deposit the tailings onto the existing pile. This paper deals with the various aspects of the project from conception to its present state.IntroductionPrevious to 1984, when the stacking project was first implemented, potash mill tailings were handled as follows. Mill tailings were first debrined to approximately 65010 solids using a cyclone cluster. The cyclone underflows were then introduced onto a vacuum scroll filter table. Here the tailings were further debrined and discharged into the disposal tank where the tailings were reslurried with reclaim brine and pumped to the tailings disposal site. At the disposal site the slurry was discharged onto the tailings pile and by a natural settling process the tailings were debrined with the brine ultimately collected in the reclaim brine ponds. The shape and profile of the tailings pile was controlled by building salt dykes to control the flow of the discharged tailings slurry. As the tailings pile grew in height, booster pumps were added to the disposal system."

Jan 1, 1990

By F. P. Yungwirth

"IntroductionTrout Lake Mine is located about 5 km north of the Hudson Bay Mining and Smelting Co., Limited complex at Flin Flon, Manitoba. The mine was brought into production in 1982at the onset of a severe recession in the base metal market. The mine is operated as a joint venture with HBM&S, MMR and SMS.During the first several months of operation it became evident that there were opportunities to reduce costs at the mine significantly, and a productivity improvement subcommittee was formed to make recommendations. The first committee met in January, 1983 and consisted of the mine manager from Hudson Bay Mining, a geological expert and a maintenance expert from Outokumpu Oy, Finland, and a mine manager from Granges, Sweden.Recommendations from this committee were implemented during 1983 and a new subcommittee was constituted in 1984 to continue the work begun the previous year. The committee remains as constituted in 1984 and meets quarterly.The committee consists of M.A . Kirby , manager - Flin Flon Mines, HBM&S; Gustav Hoberstorfer of Mindelco , a Swedish mining consultant retained by Granges; Eero Laatio, mine superintendent of Keretti Mine at Outokumpu Oy in Finland; and Bob Bray, a mining consultant retained by Manitoba Mineral Resources.Many productivity improvements made in the operation are attributed to the work of this committee and other experts retained at various times throughout the mine life."

Jan 1, 1988

By Leiting Yue, Peng Ren, Yu Shen, Zhihong Liu, Haibao Shao, Longgong Xia, Feng Yu

The Kennecott-Outotec Flash Converting technology has been proven as an advanced and mature process in 5 individual plants during the past 2 decades. High grade copper matte (65–72%) produced in the flash smelting, or other smelting technologies is granulated to 3-5mm granules in a water torrent, and further crushed to fine powder (≈50µm) and dried to contain less than 0.3% H2O. Oxygen enriched air, together with fine copper matte powder and lime flux are injected into the reaction shaft by a matte burner. The copper making and slag making reactions will happen in very short time and distance during the particle falling and settling. However, industrial practice has found negative effects caused by sodium contamination. Na is introduced in the copper matte granulating process, and appears as Na2SO4 on particle surface. When Na content was high, scaling problems in the boiler will be worse, and the processing air will be blocked by the growing accretion around the matte burner, and as-produced blister copper is always high in S and O. In this present study, an industrial matte sample was used in the experimental work. Na was introduced into the matte powder by Na2SO4 solution soaking. The burning behaviour of the doped copper matte powder has been investigated as a function of the impurity concentration and processing temperature. Morphology and composition of these samples explained how Na2SO4 converts and reacts in the oxidizing atmosphere, and how they or their converting species influence the burning behaviour of matte particles. Cross-sections of as-prepared samples were analyzed with SEM-EDS, and the reaction mechanism has been carefully interpreted. Results from the present study can benefit both academic and industrial people. INTRODUCTION "Flash Converting" technology was developed jointly by Kennecott Utah Copper Smelter and Outotec (Finland) OY in 1992. The first industrialization of the technology was in Utah Smelter in 1995. Since 2006, it has been successfully applied in Xiangguang Copper, Tongling Jinguan Copper Branch, Fangchengang Jinchuan Copper, and Ningde Southeast Copper. The technology has also been further developed in those smelters. At present, roughly 2 million tons blister copper is produced annually through the Kennecott-Outotec Flash Converting technology, accounting for more than 10% of global primary copper production. The technology has advantages of high efficiency, high sulfur capture rate, good in environmental issues, mature equipment supporting, high automatic control level, low comprehensive energy consumption and flexible connection with the smelting unit, which make the technology to be one of the best choices in investing a new large-scale copper smelter or updating an old copper project in the world.

Jan 1, 2019

By Matthew Russell, Bobby Randhawa, Leopoldo Mariscal Samaniego, Jose A. Puente, D. Brosig, Paykan Safe

The La Caridad copper smelter, located in Nacozari, Mexico, have started a multi-year plan to reduce sulfur dioxide and particulate matter emissions into the environment. In 2014 the smelter completed a voluntary plant-wide SO2 process emissions inventory as part of the smelter’s proactive environmental stewardship policy. In turn, this triggered the development of several environmental projects to alleviate these emissions. A strategy consisting of improved capture efficiency of the sources with greatest impact has been followed to maximize cost-effectiveness. The reduction of secondary emissions from the Teniente Converter, as well as of primary and secondary emissions from the Peirce-Smith Converters have been key areas of priority. Additionally, a new system to capture and recover particulate matter from the Anode Refining Furnaces off-gas is also in the process of being implemented. This paper presents an overview of the work developed behind this effort and the smelter’s vision towards a greener future. INTRODUCTION The La Caridad copper smelter is owned and operated by Metalurgica de Cobre S.A. de C.V. (a subsidiary of Grupo Mexico). Currently, the smelter has a production capacity of 300,000 tonnes of anodic copper per year. The smelter is coupled with a 300,000 t/y electrolytic refinery. Other by-products (such as precious metals and sulfuric acid) are also generated as part of an integrated process. The original smelter started operating in 1986 with one Furukawa concentrate dryer, one Outokumpu Flash Smelting Furnace (FSF), two slag cleaning electric furnaces (SCFs), three Peirce-Smith Converters (PSCs), two Anode Refining Furnaces (ARFs) and one casting wheel. In 1997, a plant expansion project was concluded with the installation of one steam dryer, one Modified Teniente Converter (MTC), one additional ARF, one additional casting wheel, and the electrolytic refinery [1]. Over the years, the smelter management has implemented numerous environmental projects to alleviate SO2 and particulate matter (PM) emissions. The smelter process gas handling system captures the process gases from the FSF, MTC, and the three PSCs. The process gases are cleaned and conditioned and sent to the two acid plants. The first acid plant (with a capacity of 226,000 Nm3/h, wet basis) was commissioned in 1988 to process the FSF and PSC off-gases. A second acid plant (with a capacity of 195,000 Nm3/h, wet basis) was commissioned as part of the smelter expansion project [1]. The PSCs also have a secondary gas handling system with a dedicated baghouse and stack. The Furukawa dryer off-gas reports to a dedicated electrostatic precipitator (ESP) for dedusting before venting via a local stack. Process gas from the two SCFs, along with hygiene ventilation from various sources inside the smelter (including matte and slag tapping hoods from the FSF) report to a baghouse-based gas handling system and vent to atmosphere via a local stack. The original ARFs do not have an off-gas handling system, however, each ARF has a post- combustion chamber which naturally vents the process gases to the atmosphere via a dedicated stack.

Jan 1, 2019

By M. Dotto, T. G. Joseph, M. Curley

"Equipment selection is a key decision in mine planning. Equipment size affects decisions from pit size to the total operation cost. Particularly when replacing haulage fleets for long-life surface mining operations, mining operations focus solely on haulage productivity. Road width and specifically ramp width are significantly affected by an increase in hauler size in terms of overall strip ratio through required highwall set-backs or sterilizing of lower ore access due to required overlying ramp fill structures. In addition, in light of ever increasing regulatory and reporting emissions requirements, bigger equipment may not translate into lower emissions per tonne moved. This study analyzes hauler-scale impacts on aspects not currently incorporated into conventional mine planning, including expansion of roads to accommodate larger equipment, road layer thickness variation depending on hauler size, and fuel consumption and emissions. Results indicate that such relationships have a large impact on cost. Therefore, an expanded consideration of the capacities of increasing equipment size in mine planning is highly recommended. ¦ KEYWORDS Equipment selection, Grade resistance (GR), Haul road, Haul truck, Mine planning, Payload, Rolling resistance (RR), Total resistance (TR) RÉSUMÉ La sélection du matériel est une décision importante dans l’aménagement des mines. La taille de l’équipement a une incidence sur la prise de décisions, depuis la taille de la fosse jusqu’aux coûts totaux des activités. L’exploitation minière se concentre uniquement sur la productivité des moyens de transport, particulièrement lorsqu’il s’agit de remplacer les parcs de camions de transport dans les exploitations à ciel ouvert à longue durée de vie. La largeur des routes, et spécifiquement la largeur des descenderies sont considérablement affectées par une augmentation de la taille des camions de transport en termes du coefficient global de recouvrement qui dépend de la taille requise des parois (si les descenderies sont agrandies, les parois devront être creusées de haut en bas afin d’agrandir la taille du fond de la fosse). Il faut aussi pouvoir procéder à l’excavation des gradins les plus profonds de la mine et ainsi préserver l’accès à cette zone, ce qui pourrait devenir difficile si la quantité de stériles utilisés pour la structure des descenderies augmente et s’ils occupent une trop grande partie du fond de la fosse. En outre, au vu des exigences de plus en plus strictes en matière de réglementation et de déclaration des émissions, un équipement plus volumineux ne sera pas nécessairement synonyme d’une réduction des émissions par tonne déplacée. Cette étude analyse l’incidence de la taille des camions de transport sur des aspects actuellement non intégrés dans l’aménagement classique des mines, notamment la création de routes permettant le passage d’un équipement plus volumineux, la variation de l’épaisseur de la couche d’asphalte des routes en fonction de la taille des camions de transport, ainsi que la consommation de carburant et les émissions. Les résultats indiquent que ces relations ont des répercussions importantes sur les coûts. Ainsi, on recommande d’accorder une attention accrue aux capacités d’augmentation de la taille de l’équipement dans l’aménagement des mines. ¦ MOTS CLÉS aménagement des mines, camion de transport, charge utile, résistance au roulement, résistance due aux rampes, résistance totale, route de transport, sélection du materielINTRODUCTION Over the past five decades, the mining industry has progressively attempted to increase production rates through the use of larger haulage equipment. Each new generation of mine is designed to operate with the most recent and often bigger equipment iteration, while older mines are re-evaluated to keep pace with upgraded mixed fleets. Whereas production gains are often realized with larger equipment, there are additional aspects to consider when evaluating the feasibility of mo"

Jan 1, 2019

By Robin N. Adair

The Halfmile Lake stratiform volcanogenic massive-sulfide deposit consists of pyrrhotiterich breccia-matrix sulfides and pyrite-pyrrhotite-rich layered sulfides that form a laterally continuous sheet stratigraphically underlain by an extensive pyrrhotite-chalcopyrite-quartz stringer zone. Mineralization is hosted by a sequence of felsic pyroclastics and volcanic-derived, fine-grained metasediments. The proportion of volcanic to sedimentary rocks indicates increasing vent proximity from southwest to northeast across the deposit area. Fine- to medium-grained felsic pyroclastics and roughly equal amounts of fine-grained metasediments comprise the stratigraphic footwall to the mineralization. Quartz-feldspar porphyritic bodies cut this sequence and may have provided the heat source for exhalite activity. Felsic tuffs, locally crystal-rich, and lesser amounts of metasedimentary rocks make up the immediate stratigraphic hanging wall. This sequence is stratigraphically overlain and locally interfmgered with mafic volcanics that contain substantial proportions of felsic fragments. Deposition of sulfides post-dated the beginning of felsic volcanism, which places the deposit in the middle of the Lower Tetagouche Group. Compositions of the volcanic rocks range from basalt to rhyolite and exhibit sub-alkaline affinities. Strongly overprinted whole-rock, trace-element, and REE geochemical signatures resulting from mineralizing hydrothermal activity confirm the genetic relationship between the stringer zone and the mineralized sheet. Large-scale D1 folding has overturned the entire sequence. D1 thrust faults and related sheath-like folds have profoundly affected sulfide distribution. D2 is manifested by a penetrative S2 foliation, and D3 is represented by large-scale open folds.

Jan 1, 1992

By Robert D. Brown

"Important tax changes, many of them of direct interest to the mining industry, were contained in the budgets brought down by federal and provincial finance ministers across Canada this spring. This month, Tax Notes presents a brief summary of important tax changes introduced at the federal and provincial levels in the last few months.IntroductionIn the March 1980 issue of the CIM Bulletin, Tax Notes surmised that the short-lived 1979 budget proposals of the former Conservative government offered a unique glimpse of budgetary changes that might be unfolded in 1980. Scene II of this ""now you see it-now you don't"" drama opened on April 21, 1980, when Finance Minister Allen MacEachen, in an ""economic statement""' reintroduced a selection of tax proposals taken from the ill-fated Conservative' budget of December 11, 1979, but refused to bring forward major new proposals in tax and finance.Mr. MacEachen proposed a 5% surtax on federal corporation income tax to apply in the 2 years from January 1, 1980 to December 31, 1981, as a slightly modified version of the same surtax proposed by former Finance Minister Crosbie in his December budget address. Mr. MacEachen also reintroduced a number of technical amendments which would affect the taxation of mining income in certain instances. In addition, a large number of other tax proposals suggested in the previous Conservative budget were also reintroduced, although there are some notable omissions."

Jan 1, 1980

By C. Sideco

"Concentrate drying at the Sullivan Concentrator goes back to 1937 when the original coal-fired dryer was put into operation. This was a second hand 8' dia. x 56' long Struthers-Wells rotary dryer that came from the phosphate plant in Warfield, B.C.In 1962, replacement of the old dryer was seriously considered. The shell and the auxiliary drive mechanism were badly worn and needed replacing. In April 1963, the new 8' dia. x 65' long fuel oil-fired Struthers-Wells dryer went in operation at an installed cost of $174,000.In 1965, it was apparent that a major rebuilding of the dust collecting system would have to be done. A study was carried out and a Ducon Dynamic Gas Scrubber was installed. The system went in operation in November 1966 and has fully met expectations.In the same year, the zinc dryer was converted from fuel oil to natural gas. The conversion has resulted in savings in fuel cost of 12 to 15%.Frame No. 1Zinc Dryer PerformanceDryer Make - Struthers-WellsDryer Size 3/4 8' dia. x 65' long Drum Drive - 100 HPSpeed of Rotation - 5 RPMFeed Rate - 50-65 TPHFeed Moisture - 10-12%Discharge Moisture - 4-6%Dryer Inlet Temperature - 1600-1800°F Dryer Outlet Temperature - 200-250°F Stack Gas Volume - 25,000-40,000 CFNDust Collecting Efficiency - 99.75-99.98% Duet Loss in Stack - 50-300 lbs./day"

Jan 1, 1972

By A. MacKinnon, P. W. Kingston, W. F. Caley

"Wollastonite (CaSiO3]) is experiencing increased usage in a variety of applications, such as fillers in paints, plastics and resins, as an extender to replace both non-fibrous and fibrous materials (e.g. asbestos), and in the glass and ceramics industries. Significant new deposits of wollastonite have been discovered in Marmora Township, about 175 km northeast of Toronto. The geological setting of these large-tonnage. High grade deposits has recently been investigated to assess the possibility of their development. A preliminary study of the chemistry, as well as the mineralogy of six occurrences is presented. Based upon this information, it is suggested that several of the deposits have an excellent development potential.INTRODUCTIONWollastonite is an anhydrous calcium metasilicate (CaSiO3), with a theoretical composition of 48.3% CaO and 51.7% SiO2; the calcium may be partially replaced by iron, manganese, magnesium, and strontium. Commonly associated minerals include diopside, tremolite, idocrase, grossularite andradite, quartz, and calcite. Wollastonite forms as a contact metamorphic mineral within impure limestone near intrusive bodies of granite, or other acidic rocks, as the result of metasomatism of calcareous sedimentary rocks, or by the crystallization of certain magmas (e.g. carbonautes). Generally, the reaction of calcite with silica to produce wollastonite occurs when siliceous hydrothermal fluids from a granitic intrusion or primary silica in the limestone/marble react with calcite in limestone at temperatures between 450°C and 600°C."

Jan 1, 1989

By G. Vibert Douglas

NICKEL minerals are known in New Brunswick but have never been reported from Nova Scotia. The attention of the writers was drawn to an occurrence of pyrrhotite, reported to carry nickel, at the Second Gold brook, Middle river, Cape Breton. The purpose of this paper is to record the occurrence and give an account of the general geological association. In a later paper it may be possible to give greater details? than are available at present. GEOLOGY The area lies at the edge of a plateau of Precambrian rocks which forms the panhandle of Cape Breton island. This plateau has a general elevation of 1,200 feet. Middle river, with its tributaries, the First, Second, and Third Gold brooks drains the area. The lower country to east and southeast of the plateau is underlain by lower Carboniferous sediments. The rocks of the plateau are presumably of Precambrian age but have never been definitely correlated with the Gold-Bearing Series of the mainland. ?There i:s; however, some resemblance, although they have apparently been more intensely mountain-built. They are essentially fine grained, sheared quartzites and slates . The general strike is east and west, with a north dip of 45° to 55°. There are smalllocal drag-folds in the area. The only igneous rock in the immediate vicinity is an intrusive pink porphyry. It has small phenocrysts of quartz and feldspar. It has intruded the sediments generally along the structural planes, but in places crosses the structure . Its intrusive character is further proved by the fact that it contains xenoliths of the quartzite.

Jan 1, 1937

By R. J. Grant, D. W. Scott, M. A. Cooper, E. R. Shannon

"The Brunswick No.12 site concentrator processes 10,500 tonnes per day of a complex lead, zinc, copper and silver ore producing four concentrates by differential flotation. Research over the years has led to increased understanding about the mineralogical and flotation characteristics of the ore. A pilot plant study conducted at Lakefield Research, primarily designed to investigate the technical feasibility of semi-autogenous grinding, provided an opportunity to test recent theories about grind size,, reagent schedule and flowsheet configuration.A fundamental approach was taken with each of the unit processes involved in grinding and flotation. Basic operating and metallurgical criteria were established in each area and a step-by-step implementation program initiated in the plant.Significant improvements in metallurgical and financial performance have been realized through the application of basic grinding and flotation principles using conventional milling equipment and without major capital expenditure. Current operating practice is detailed and metallurgical advancements cited.INTRODUCTIONBrunswick Mining and Smelting operates one of the world's largest lead and zinc mines near Bathurst, New Brunswick. Brunswick is a publicly traded company with majority ownership held by Noranda Minerals (63%). In addition to the No. 12 underground mine, the company operates a lead smelter and phosphate fertilizer plant in Belledune, N.B. and maintains a 25% interest in a joint venture with Noranda Minerals' Heath Steele mine near Newcastle, N.B. Through the four operations, a total of 2000 people are directly employed with fixed assets totalling Cdn$187 million (BM&S, 1991)."

Jan 1, 1993