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By Simon C. Dominy

"There are two main issues stemming from Vallée’s (2002) comments on Dominy et al. (2001b). First, he raises the importance of quality assurance/quality control (QA/QC) during resource estimation programs, and second, he indicates that the resolution and understanding of continuity (grade and geological) issues are paramount in the classification of resources. In particular, continuity is critical at the boundary between the Inferred and Indicated Mineral Resource categories. The original contribution agrees with the importance of these points, and the principal author offers the following discussion and clarification. Further comment is also provided on the reporting of grade uncertainty through grade ranges.It is worth remembering that vein-gold deposits (e.g., shear-zone, lode-gold, mesothermal types etc.), particularly those containing coarse gold particles (e.g., >100 µm), generally show large variations in grade and an erratic grade distribution. In most cases, diamond drilling is a good measure of geological continuity (depending on drill spacing), but a poor measure of grade and its distribution. High-nugget effect deposits rank among the most difficult deposit types in terms of producing an accurate and precise resource estimate, and clearly represent a distinct deposit type."

Jan 1, 2002

By J. H. Starkey, P. A. Scinto

"In Canada and other countries, legislation dealing with accurate factual disclosure for mining projects is being expanded to include more metallurgical design information. Grinding characteristics, metallurgical recovery of contained metal and environmental hazards associated with tailings disposal will be part of the Canadian package. This paper will examine only that portion of the plant design standard practice that relates to grinding – in SAG mills and ball mills that grind ore from as received crushed material to final ground product that is fed to downstream plant recovery processes. Since grinding plants represent a significant portion of the overall concentrator cost, accountability in grinding design should no longer be left to chance, opinion, or hidden proprietary information. This is the 21st century. It is reasonable to expect that a factual basis will be needed so that a Qualified Person (QP) reviewing the grinding mill design can understand it. That will also involve how many and what quality of samples are taken to define the characteristics of the deposit, the accuracy of the tests used to measure ore hardness and the method by which the dimensions and power of the mills are determined. If these criteria are not met, the QP may have no choice but to call attention to the lack of convincing information regarding the grinding mill design for the project. At the same time clients are expected to demand getting the correct design information at a cheaper price, results in a more timely way, and accurate design to the point where the risk of tonnage shortfalls are reduced or eliminated.Tables will be presented to show how this can be done to current standards using existing technologies. At the same time it is acknowledged that current standards are ill-defined and that to achieve consensus among those involved in SAG mill design work, it may require that a consortium funded project be set up to establish what tests and methods for grinding design are suitable to meet the new standards for metallurgical disclosure. By running parallel design methods on several major projects over a period of 5 years, the process of how to design grinding circuits will be better understood because the projects will start at the design stage, include procurement of the mills and will end with a benchmark test on the plant.Selecting the samples and the best schedule for doing test work on core samples submitted and mill design, will be discussed in this paper. The issue of completing the grinding design in time for early procurement decisions is on the critical path for most major projects. Discussions between mining engineers, geologists and process engineers are needed early in the development cycle, at the scoping study level (SS), preliminary engineering assessment (PEA), prefeasibility study (PFS), and at the feasibility study stage (FS), to ensure that proper planning for design sample selection is done. Using adequate sampling and testing methods in a timely way allows early procurement of the grinding mills and minimizes project risk."

Jan 1, 2012

By B. Krysa, A. Mitsui, T. L. Koehler

The presence of arsenic, even at trace levels, in copper processing leads to the risk of arsine gas where reducing conditions exist that can reduce any soluble arsenic present to its minus 3 valance state and generate hydrogen gas from the solutions. This risk is understood to be significant within the industry, particularly in the case of liberator cells where copper concentrations in solution are drawn down to remove the copper and impurities from the bleed stream. However, there are numerous other potential areas where the arsine gas risk exists including contact between active metal such as iron, zinc or aluminum and arsenic bearing solutions in pyrometallurgical dust treatment, refining and acid plant operations. In turn this breaks down to different mitigating strategies dependent on the risk scenarios considered; for example, how this risk interacts with Change Management, Confined Space Entry or Contractor Training. The ISO 45001 is an emerging standard meant to improve employee safety, reduce workplace risks and create safer working conditions all over the world. The paper shows a case study of how a framework consistent with the tenets of ISO 45001 has been used to provide a consistent assessment of this risk for a wide variety of copper operations and the expectations of how this may be used to effectively improve the effectiveness of barriers against future incidents. INTRODUCTION Arsine gas (AsH3), first identified in 1775, is a highly poisonous, colorless, non-irritating gas with a mild garlic odor that is heavier than air. Arsine gas is generated when reducing conditions are generated in the presence of hydrogen ions and arsenic compounds. Present permissible occupational exposure limit as defined by Occupational Safety and Health Administration (OSHA) as an 8-hour time-weighted average is ppm (0.2 mg/m3). Further increasing the risk, conventional respiratory protection utilizing half or full masks with gas filtering cartridges provide minimal protection against arsine. In copper processing plants, the risk of arsine generation is well understood in liberator cells, which are part of the electrolysis process. In this process, solutions containing copper are reduced in copper concentration removing not only the copper, but also arsenic, antimony and bismuth. The residual solution can be bled to control impurity build-up in the refinery. In this process, if the copper concentration is reduced to the point where As3- can form, arsine gas is generated via reaction with hydrogen ions generated during the plating process. The copper concentration at which arsine gas is generated depends on copper concentration at the cathode surface, the temperature and the acidity. As a result, there is always a risk of arsine gas generation in the liberator cell. Process measures to minimize or mitigate arsine evolution are tight control on final copper concentration, warm temperatures, fresh feed distribution and internal acid recirculation rates. Operator exposure protection measures are hooding, ventilation, arsine detection systems, restricted personnel access, automated shutdown controls and pre-defined evacuation plans.

Jan 1, 2019

By W. L. Stuewe

The Dominion Steel and Coal Corporation requires enormous quantities of bricks each year for its Sydney steel plant operations. Clay brick of all types are purchased, while silica brick is made in the Company's plant at Sydney. A description of this plant was given in a paper presented by H. B. Gillis and F. C. Morrison at the 1938 Annual General Meeting of the Institute. The rock used to make silica brick was for years obtained from a quarry at Leitches Creek, about eighteen miles from Sydney. Due to the gradual deterioration of this deposit, the Corporation was forced to look for other sources of supply. In 1945, the problem was presented to the Nova Scotia Department of Mines and, through the efforts of Dr. A. E. Cameron and Mr. J. P. Messervey, an examination was made of a silica-rock deposit some six miles northwest of Yarmouth, N.S. Preliminary samples proved satisfactory, and arrangements were made with the Department of Mines to ship to the steel plant at Sydney a fifty-ton car load for the purpose of further testing. Brick made from this sample shipment stood up very well in the furnaces. At the same time, two hundred and fifty tons of silica rock from a deposit at Lac Bouchette, Que., were purchased from the Industrial Silica Corporation, and brick made from this rock also was found suitable for our requirements. Comparative transportation costs, however, led to a decision to open the Yarmouth deposit. The silica rock, or quartzite, of this deposit outcrops at Chegoggin point along what is known as the 'Pembroke shore', a northerly trending section of the coast-line at the extreme southwest of the Province, in Yarmouth county. The country here is fairly flat, with elevation averaging about twenty feet above high tide, and is for the most part mantled by a growth of brush and some scrub trees, chiefly small fir. Bed-rock is generally concealed beneath three to four feet of clayey soil, but scattered outcrops of the quartzite indicated that a band of this rock, some 260 feet wide, extended inland in a northeasterly direction from Chegoggin point at least to Utleys lake, a distance of about three miles.

Jan 1, 1947

By Carmen Mihaela Neculita

Sulfate-reducing passive bioreactors efficiently treat acid mine drainage (AMD) by increasing its pH and alkalinity and by removing metals as sulfide precipitates, in addition to hydroxides and carbonates. However, the new mining legislation sets discharge limits based on physicochemical parameters and on the non-toxicity of treated effluent as well. In this study, toxicity was assessed for effluent from 3.5 L column bioreactors filled with mixtures of natural organic carbon sources and operated at two different hydraulic retention times (HRTs) of 7.3 d and 10 d for the treatment of a highly contaminated AMD. Acute toxicity was observed for D. magna, and a toxicity identification evaluation (TIE) procedure was performed to identify potential toxicants. To help the interpretation of the toxicity results, metal partition in the effluent was also determined by filtration and ultrafiltration, while geochemical modeling was performed for metal speciation evaluation. The 10 d HRT effluent was nonacutely lethal for rainbow trout but acutely lethal for D. magna, whereas the 7.3 d HRT effluent was toxic for both organisms. The toxicity to D. magna was eliminated by 2 h of aeration for the 10 d HRT effluent, and the TIE procedure suggested iron as a cause of toxicity. However, the 2 h aeration eliminated the toxicity of the 7.3 d HRT effluent, only if performed after the pH rising to 9.3. Data regarding metal speciation indicated instability of both effluents during aeration and were consistent with the toxicity being caused by iron. The study indicates that design of passive treatment should include sufficient HRT and posttreatment aeration to meet acute toxicity requirements. Keywords: acid mine drainage, sulphate-reducing passive bioreactors, hydraulic retention time, effluent toxicity, metal speciation

Nov 1, 2008

By A. Noël, R. Lapierre, M. Provencher

"Modem aluminum smelters are facing significant operating cost pressure. Key methods used by smelters to manage this pressure are automation and production-information systems to optimize processes, manage quality, anticipate problems and reduce operating costs. In 2002, Aluminerie Alouette Inc. began its Phase II Expansion project, and retained the joint venture of SNC-Lavalin and Hatch (SLH) as its engineering, procurement and construction management (EPCM) team. Alouette had the distinction of being one of the most efficient aluminum smelters in the world. Alouette already understood the importance of systems integration in project delivery. For Phase II, key objectives were identified to ensure ""a state of the art"" integrated architecture that would support Alouette's production goals to integrate the existing facilities with the expansion, to form a single efficient facility and meet project schedule and budget targets. Achieving those objectives within the context of a large project often creates major challenges due to the nature of the traditional EPCM delivery model, which relies on several vendors and third-party-systems integrators. In this case, an integrated Alouette-SLH team was made responsible for all aspects of the systems integration, taking over the task from most suppliers. The integrated team was responsible for delivering an automation system and plant-wide-production IT system for the new facilities while accommodating migration for the existing systems. Through the use of rigorous methodology and advanced state of the art technology, the IT and automation strategy led to significant value creation and is recognized today as one of the key factors of the project's success. The primary results were: fast and efficient start-up of facilities, due to quality programming and implementation; a plant able to operate as a single entity; automation and IT systems delivered before time and under budget; standard programming methods implemented throughout the plant; and reduced and simplified maintenance."

Jan 1, 2006

By Giles St. Pierre

"The purpose of this paper is to report in a general way on the use of the Portaspec X Ray Spectrograph.At Manitou Barvue, we are milling two types of ores, copper and zinc. The control assay practice was to take grab samples at 4 hour intervals. These samples were dried in the mill, then taken over to the Assay Office where two operators would process them. Three hours later results were available at almost the same time as the operator was ready to take his set of grabs again, leaving no time for adjustments, if any were needed.After a reduction of personnel, there were no assays available on night shift. This practice was slow and inadequate, and a new way of doing control assays was investigated.After investigation the Portaspec was found suitable for the type of operation that we had in mind. The Portaspec is a conventional dispersive type of X Ray spectrograph. The instrument consists of three parts:The Power Supply The Spectrographic Head The Digital ScalerIn our case, where dried powder samples are analyzed, the instrument was provided with a two sample holder using one for the standard and the other for the sample. The operation of the instrment does not require any degree of skill or knowledge of chemistry or spectrography.Previous to buying the instrument, six sets of six to ten samples were sent to the supplier along with the assay for each sample. These samples were Cu. HDS., Cu. Conc., Cu. tls, - Zn. HDS., Zn. Conc., Zn. tls. A definite pattern was observed. For example - six Cu. HDS. samples ranging from .40 to .90 gave 10400 counts for the lowest to 16.040 counts for the highest. The number of counts were then plotted to give percentages."

Jan 1, 1971

By Forrest A. Kerr

The subject of the Coast Range batholith and its eastern contact zone needs no introduction to British Columbia mining men. Because of its reputed potentialities, this zone has aroused much interest. Because it has touched the pockets of the people by actually producing dividend-paying mines, it has been able, more particularly in certain isolated sections, to retain and accentuate that interest. However, the Stikine River section of the zone has never had the good fortune to have a mine developed, which, through profits or lack of profits, could create such interest. The Cassiar district, beyond the Stikine River area, has been a lure to the prospector for over half a century and was still strong enough in the last few years to attract close to a million dollars in capital and labour. All of this has passed through the Stikine river area, has looked at it, and ignored it. Sufficient interest has never been aroused in the area to bring forth an effort to see what is there, in spite of the fact that it belongs to the same zone in which some of our richest mining camps are located. Because the contact zone of the Coast Range batholith has long been recognized as an ore producer of considerable potentiality, the Geological Survey some years ago formulated a plan to map as much of this area as possible in order to assist in promoting its development. This plan has been furthered during the last fifteen years whenever opportunity presented itself, until today a fairly large part of the area has been covered. The work which has been done on the Stikine during the last two years is the beginning on what is the largest remaining gap in the general plan.

Jan 1, 1928

By Harry Piers

A RAPID glance over the history of The Mining Society of Nova Scotia shows that in its fifty years of service, which it is now rounding out, the Society has had an honourable career, rendered signal service to the mining industry of the Province, and helped to shape and improve legislation bearing on our mines and minerals, besicles publishing very many excellent papers and subsequent discussions thereon dealing with all subjects in its field of activity. THE GOLD MINERS? CLUB OF NOVA SCOTIA: The Society has the distinction of being generally regarded as the oldest mining fraternity in Canada ( 1). Iris the direct outgrowth or reorganization of The Gold Miners' Club of Nova Scotia, which was organized in March, 1887, at a period when the gold mining industry was very prominent in the Province. Mr. Geo. W. Stuart, who, in 1934, was the only living member of the parent association, informed me that the seventeen Charter Members of The Gold Miners' Club were John H. Anderson, Charles F. Andrews, A. B. Cox, Clarence H. Dimock, George E. Francklyn, L. W. Getchell, John E. Hardman, Alonzo A. Hayward, Major R. G. Leckie, W. L. Libbey, Edward M. McDonald, G. F. McNaughton, George A. Pyke, H. A. Sanders, C. E. Willis, Benjamin C. Wilson, and George W. Stuart. Others joined later in the same year.

Jan 1, 1937

By W. G. Wahl

The Slave Province, a segment of Archean continental crust, migrated west and north from the northern flank of the Superior protoshield shortly after the Kenoran orogeny. The probable cause of migration, the path it followed and the cause of its coming to rest can be inferred from the Bouguer gravity data. The migration caused an indentation in the edge of the Superior protoshield which precluded the development of the Hudsonian orogenic front under Hudson Bay. As the nickel and asbestos deposits of the Thompson Nickel Belt and the New Quebec Nickel Belt are restricted to this orogenic front, no such deposits would occur under Hudson Bay.

Jan 1, 1973

By A. Majumdar, B. Servière, H. Persson

The CCR refinery, which was built in 1931, treats both internal and third party copper anodes to produce 325,000 mt of copper as cathodes. These anodes contain high levels of impurities, such as Ni, As, Sb and Bi, that reports to the electrolyte during the refining step and need to be removed in order to maintain cathode quality and operating efficiencies. In the purification plant, the electrolyte is de-copperized via electrowinning in three stages. In the last stage, the copper content of the electrolyte is reduced to below 1 gpl in order to maximize the co-deposition of As, Sb and Bi with the Cu. This is accomplished with minimum arsine gas generation by using periodic reversal of the current and by controlling the final copper content of the electrolyte. Nevertheless, the possibility of exposure to arsine is treated as a major risk and controls have been implemented to reduce this risk. This paper describes the controls in place at the purification plant, which are being continuously improved through periodic risk assessments and audits. INTRODUCTION The CCR Refinery, which is a part of Glencore Canada Corporation and located in Montreal-East, Quebec, is a custom copper and precious metal refinery, with a capacity to refine 325,000 tonnes of copper anodes per year. Copper anodes are received from the Horne smelter in Rouyn-Noranda, Quebec, Altonorte smelter in Chile and other 3rd party smelters. CCR anodes are produced using the spent anodes from the tankhouse along with purchased spent anodes and copper scrap. The precious metal plant treats the tankhouse anode slime, purchased anode slime, precious metal ingots and Doré anodes from Glencore’s Brunswick lead smelter in Belledune, New Brunswick. CCR products include copper cathodes, silver and gold bullion, a platinum-palladium concentrate, selenium, tellurium dioxide and nickel sulfate. In 1975 an accident occurred at CCR where two employees were exposed to fatal levels of arsine emitted from the then existing purification cells. This process was therefore shut down immediately. Research and development work was then initiated to determine the optimum electrowinning conditions whereby arsine gas generation would be minimized while maintaining high copper and impurity removal efficiencies. It was found that the application of periodic reversal of current (PRC) during the last stage of electrowinning retarded the onset of arsine formation while at the same time allowing the copper concentration to be reduced to less than 1 gpl (Houlachi & Claessens, 1978). A new purification plant was designed based on the PRC technology and was started up in 1976. In addition to the use of PRC electrowinning, the new plant is located in a fully enclosed section of the tankhouse. A special effort was made to design a ventilation system to evacuate the acid mist in addition to any arsine gas. Arsine monitors were installed to measure the emissions from the stack along with arsine levels in the workroom. The arsine monitors and the ventilation system were interlocked with the rectifiers (Thiriar et al., 1983).

Jan 1, 2019

By D. W. Davis, P. Landais, L. J. Robb

Nodules of carbonaceous matter have been observed in several Archaean peraluminous granites adjoining the gold- and uranium-bearing Witwatersrand Basin. These nodules, which resemble solid bitumen, usually replace uraninite or uranothorite and are paragenetically late. They show many similarities to kerogen seams and nodules associated with the conglomerate horizons in the Witwatersrand Basin, including composition, maturation, intimate association with uraninite, and a late paragenesis. U-Pb isotope ratios for granite-hosted and Witwatersrand kerogens define a single, albeit somewhat diffuse, Ph-loss discordia suggesting an upper intercept age of circa 2300 Ma. Carbon isotope analysis indicates lighter Ol3C values for the granite-hosted nodules than for the sediment-hosted kerogen seams. Raman spectroscopy indicates that granite-hosted kerogen is more highly ordered than Witwatersrand seam kerogen. A model is presented which links the granitoidand sediment-hosted organic matter to an event of oil generation in the Witwatersrand Basin circa 2300 Ma ago. Light hydrocarbons migrated through the sediments and into underlying/adjacent granitic rocks, undergoing polymerization and accumulation in response to radiation accompanying the presence of high-uranium phases.

Jan 1, 1994

By B. Oraee-Mirzamani

One the most important tasks after excavation of tunnels is the implementation and installation of a support system. Tunnel collapse poses a safety hazard and can cause worker injuries. In addition, it may have a severe economic impact because tunnel collapse can stop production and ore transportation. Therefore, an appropriate and well-designed support system is necessary for collapse prevention and to help stabilize the tunnels. In this research, we suggest a support system for the Parvade1 underground coal mine. The study case is a common mining roadway tunnel in the E1 longwall panel in this mine. To design an appropriate support system, we used the finite element method (Phase2 software). The results of this research can be used to design support systems for future tunnels in this mine and any coal mine that has similar conditions.

Aug 1, 2013

By S. I. Saif

The Key Anacon deposit lies about 6 miles northeast of the Brunswick NO.6 mine of Brunswick Mining and Smelting Corporation. Geological mapping, especially in the well-exposed Nepisiguit River section, geophysical data, and information from extensive underground and some surface drilling show that the rocks at Key Anacon are similar in many aspects of stratigraphy and structure to those of the Brunswick Mine area. They include narrow beds of fine acid volcanic material interpreted to be metatuff and volcanogenic metasediments. The massive sulphide ore body at Key Anacon lies immediately above these acidic rocks, in association with other chloritic, sideritic or magnetic iron-rich metasediments. The iron formation, which is similar to that associated with other orebodies in the district, is overlain by massive andesitic material. Four phases of structural deformation have been recognized in the Key Anacon area; they are similar in intensity and style to those of the Brunswick No. 6 mine area. The orebody lies in a zone of complex isoclinal folding along the flank of a major F2 fold (Key Anacon Syncline) and in general appears to be stratiform. The ore occurs in probable F2 parasitic folds, and this suggests a complicated structural geometry superimposed on the original beds. The general similarity of the mineralization at Key Anacon, together with its occurrence with other iron-rich metasediments between a footwall of acid volcanic material and overlying andesitic rocks, is suggestive of stratigraphic time-equivalence with the Brunswick zone . If so, the metavolcanics at Key Anacon might have been derived either from a center within the main volcanic pile to the west or from a smaller local center active at the same time. Alternatively, the Key Anacon ore could have been formed during a much older volcanic cycle. The solution to this aspect of the problem is the subject of a continuing study.

Jan 1, 1978

By M. Specht, D. Pörzgen, W. Lorenz, A. /. Buhr, R. P. Racher

The introduction of the near net-shape casting process at CORUS Staal IJmuiden in January 2000 required changes of secondary metallurgy processes including a development towards more aggressive slag compositions in the steel ladle. Therefore the steel ladle lining has been changed from fired andalusite bricks to magnesia-carbon bricks and, most recently, to fired spinel bricks to withstand the severe slag conditions. In comparison to the andalusite bricks the new steel ladle linings have a higher thermal conductivity. This requires the capability to keep the lining warm by ladle preheaters to sustain the overall thermal stability of the steel ladle in case of interruptions during hot cycling of the ladles.

Jan 1, 2004

By P. E. Walker, M. E. Reed, R. C. Sims, B. Snowdon, D. E. Fallas

An advanced Flash Furnace feed system is the key to improving furnace performance. Clyde-WorleyParsons has developed a revolutionary pulseless pneumatic injection feed system technology, capable of delivering a range of benefits to operators of Flash Furnaces. The solution was created by combining the pneumatic conveying and injection knowledge, expertise and technology of Clyde Materials Handling with WorleyParsons' flash furnace process and operating experience. Optimal furnace burner performance requires the feed material to be presented to the burner as a stable, pulseless and accurately controlled flow, distributed evenly around the burner tip circumference. These simple requirements appear obvious, but are extremely difficult to satisfy in industrial environments and are not achieved by conventional feed systems. Our analysis of existing operating furnaces has identified the link between pulses in concentrate feed rate caused by conventional drag chain conveyors and rapid fluctuations measured in the furnace pressure. These fluctuations occur at a timescale close to the reaction shaft residence time and lead to unwanted instability in the primary furnace reaction zone - the flame. Through the use of the solution created by Clyde-WorleyParsons, it is predicted that the much more accurate control of feed rates achieved can lead to substantial improvements in furnace output, increased oxygen efficiency and better control of the composition of furnace liquids, such as matte, blister or slag. All these improvements lead to significant increases in smelter output and efficiency, and deliver high economic value compared to the cost of the feed system. Clyde-WorleyParsons' solutions can be deployed on greenfield sites or retrofitted, and therefore, have the capability to improve feed control at both new and existing smelters. This paper will discuss the field test work undertaken to date, the impact of findings and the ongoing analysis of linkages between instabilities in the various components of conventional feed systems and furnace pressure stability.

Jan 1, 2007

By J. H. Rickard, D. H. Watkinson

"Abstract - Detailed petrographic and quantitative (electron microprobe, SEM-EDS) mineralchemical analyses of sulfide ore from the 100 orebody at the Copper Cliff North mine, Copper Cliff, Ontario, reveal numerous stages of ore development. Sharp contacts between weakly mineralized quartz diorite and blebby to massive sulfides indicate multiple intrusive events within the Copper Cliff offset dike. A spatial association of sulfides and hydrous minerals, such as amphibole, biotite, chlorite and epidote, suggests that most primary ore has been affected by later hydrothermal fluids. Sulfides are often enclosed or bordered by these secondary silicate phases. The ore consists primarily of pyrrhotite, pentlandite, chalcopyrite, with trace michenerite, cobaltite/gersdorffite, irarsite, hessite, tsumoite, and bismuth tellurides.Geological and petrological comparison of the 100 orebody and the adjacent 900 and 890 orebodies has revealed distinct similarities in ore distribution. Data show that the 100 orebody is depleted in platinum-group elements (PGE) relative to the 900 orebody. Platinum-group elements from the 100 orebody may have been hydrothermally remobilized and partly emplaced in the 900 orebody, in adjacent veins, or in magmatic breccia. Analysis of Cu, Ni, and PGE assay data of ore samples has characterized their distribution among the eight different ore textures in the orebody. There is a strong association between Pt and interstitial sulfide, and to a lesser extent massive sulfide, but little correlation between chalcopyrite-rich ore and PGE in the 100 orebody, unlike many other deposits in the Sudbury region."

Jan 1, 2001

By Robert A. Creaser, Iain Mitchell, Robert L. Linnen

Abstract - The Bermuda Zn-Pb showing is hosted by dolomitized Blue Fiord Formation of Devonian age, located east of the Ensorcellement dome on the Grinnell Peninsula of Devon Island. Fluid inclusions in hydrothermal calcite indicate that the mineralization precipitated from low-temperature, highly saline brines. The ?34S compositions of sphalerite, galena, and marcasite range from 16.1‰ to 35.2‰. Consequently, the Bermuda showing is interpreted to be Mississippi Valley-type (MVT) mineralization. The apparent age of mineralization has been determined by the Rb-Sr method from sphalerite separates, and a Late Devonian age of 357 ± 50 Ma (MSWD=65), with an initial 87Sr/86Sr ratio of 0.7083 ± 0.0020 is indicated. This date, within error, is the same as the Polaris deposit. This suggests that the mineralization formed during the Ellesmerian Orogen, although it is also possible that mineralization is associated with extension, related to the opening of the Sverdrup basin. The strontium and sulfur isotopes and fluid inclusion analyses indicate the involvement of a brine that acquired its salinity from interaction with evaporites, lower in the stratigraphic succession. The Polaris mine is the type deposit in the Cornwallis Zn-Pb district and is hosted by the Thumb Mountain Formation. The results of this study are significant because they demonstrate that regional brine movement is more widespread than previously recognized, and that MVT mineralization in the Cornwallis Zn-Pb district is not restricted to the Thumb Mountain Formation.

Jan 1, 2004

By D. J. MacKinnon

Zinc metal was first produced in India around 1100 A.O. and a zinc industry based on retorting gradually developed in both India and China(1) . The vertical retort method for smelting zinc ores was developed in England in the 1730s; this was followed by the more fuel efficient horizontal retort process developed by the Belgians in the 19th century(2) . The horizontal retort process was the standard method of zinc manufacture until the 1950s when it became obvious that it could not compete with electrolytic zinc technology(2). The present day extractive metallurgy of zinc is dominated by the electrolytic process which now accounts for almost 80% of the world's primary zinc production. In recent years the electrolytic zinc process has seen significant improvements: the fluid-bed roasting of zinc concentrates, improved leaching and residue treatment techniques such as the jarosite and goethite processes, improved solution purification procedures, mechanization of the zinc electrolysis step and of the zinc melting and casting operation. In addition, new leaching processes have been implemented for the treatment of oxidized ores, particularly silicates, and the pressure leaching of zinc sulphide concentrates is now a commercial reality. Although the electrolytic zinc process was first used on a commercial scale in 1916, its history can be traced back to the 1860s. The purpose of the present paper is to outline the early history of the electrolytic zinc process and to trace the significant developments which led to the first successful commercial electrolytic zinc plants.

Jan 1, 1999

By Y. Masuda, Y. Nakamura, K. Haraguchi, A. Taniguchi, K. Arita

Availability of the elements originating from steelmaking slag for various marine phytoplankters including purely cultured strains and natural populations was tested in land and shipboard laboratories. The results obtained demonstrate that, although their solubility was not uniform among different slags, dissolved iron, silicate and phosphate from the slag stimulate phytoplankton growth. No negative effect of the slag addition on their growth was observed at lower dose, e.g. less than 200 mg/l. Since most coastal waters are the hypernitrogenous environment due to anthropogenic load of ammonium, the slag can be an ideal source of silicate and phosphate, which restore the hyper-nitrogenous condition into truly eutrophic condition with balanced Redfield ratio. In so-called HNLC (high-nitrate low-chlorophyll) oceanic areas such as the Southern Ocean and the subarctic North Pacific, where iron is almost only limiting factor of the phytoplankton growth, the slag could also be a source of iron and enhance CO2 fixation by phytoplankton photosynthesis. (Key words: carbon deposition in deep-sea, marine environmental remediation, phytoplankton, slag as a source of iron, phosphate and silicate.)

Jan 1, 2004