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By P. D. Duever, P. J. Readyhough, P. L. Silveston

"The Plastojrost apparatus, developed by Ritter and Juranek in the 1960s has been modified primarily, to automatic temperature control. A limited investigation of carboniferous and cretaceous coal samples showed that both coals undergo the same changes when coked in the Plastofrost unit. Dilatometer plastic range and total dilatation correlated well with the Piastofrost plastic range for the carboniferous Appalachian coal, but not for the cretaceous western Canadian coal. Work to elucidate the characteristics of some western Canadian coals using the Plastofrost is in progress. IntroductionCoke quality is critically affected by the properties of the plastic phase in the coal-to-coke transformation. Since these properties exist in a coke oven and are not measurable, they are approximated by standard laboratory tests, such as free swelling index, plastometry, and dilatometry. Of particular interest to us is the anomalous behaviour of western Canadian coals of cretaceous origin. By many predictive methods, these coals should not produce coherent cokes. When coked in pilot scale test ovens, in fact, they produce cokes of good stability. They typically make up 20% of Japanese coking coal blends and are also used in South Korea, Mexico, Brazil, and several European countries. This anomalous behaviour has been studied in our laboratory<8.9.1O). Plastic properties or rheological tests examine just the external ramifications of the coal-to-coke transformation. To understand the process, however, microscopic examination of the coal and coke seems to be needed. The Plastofrost unit has been shown to be a convenient means to this end."

Jan 1, 1987

By Victor Maksaev, Marcos Zentilli

"Abstract - The Domeyko Cordillera, the westernmost uplifted crustal block of the composite High Andes of northern Chile (20°S to 28°S) hosts a narrow N-S trending belt of Late Eocene-Oligocene giant porphyry copper deposits, which include Collahuasi, Chuquicamata, El Abra, La Escondida, and El Salvador. These deposits are spatially and genetically associated with the closing igneous activity along this range, prior to a 30 km eastward jump of the magmatic front in response to tectonic plate interaction. The porphyry copper deposits are also spatially associated with a major intraarc strike-slip shear system, the Domeyko Fault System. Although the tectonic uplift of the 3000 m to 5000 m high range has generally been assumed to be mostly Miocene in age, field relationships suggest that the Domeyko Fault System and tectonic uplift were active as early as the Eocene, coinciding with porphyry copper emplacement between 41 Ma and 30 Ma. Apatite fission track (FT) thermochronology provides both age data and a time-temperature history for rocks since they cooled below a temperature of ca. 125°C (equivalent to a depth of 4 km to 5 km under normal geothermal gradients) on their way to the surface during exhumation, or after a heating event. Apatite FT data from the Paleozoic crystalline basement of the Domeyko Cordillera indicate that at least 4 km to 5 km of rocks were eroded during exhumation of this tectonic block between ca. 50 Ma to 30 Ma (Middle Eocene to Early Oligocene), a time that immediately precedes and overlaps with the emplacement of giant porphyry copper deposits. The FT data constrain the age and duration of a period of crustal thickening and extensive erosion known as the Incaic compression, an event recognized in the Andes of Chile and Peru. Assuming that cooling was due to denudation alone, modelling of the FT data allow estimation of denudation rates between 200 and 100 m/My during this period. In contrast, exposures of pre-porphyry Paleocene intrusives on the western edge of the Domeyko Cordillera reveal apatite FT ages that are concordant with biotite 40Ar-39Ar dates, indicating shallow emplacement, fast cooling and negligible exhumation. The apatite FT ages of the Chuquicamata and El Abra porphyry copper deposits are only marginally younger than their 40Ar-39Ar dates, implying fast cooling/exhumation of shallow mineralizing systems (ca. 2 km to 3 km). Their FT time-temperature history is compatible with extremely low rates of exhumation (ca. 50 m/My) since about 30 Ma (Early Oligocene). This limited extent of erosion, due to exceptional aridity, has greatly contributed to the preservation of rich supergene enriched blankets above some of the porphyry copper deposits.A model is proposed, which is consistent with field relationships, geochemical, and geochronological data. High relative velocities and intermediate-angle oblique convergence between the Nazca and South American plates in the Eocene-Early Oligocene led to intra-arc transpression partitioned into reverse faults of opposing vergence and a right-lateral shear system (the Domeyko Shear System) localized along the magmatic front. Crustal shortening and thickening led to uplift within the Domeyko Fault System and to erosion of at least 4 km to 5 km. Crustal thickening deepened the zone of magma generation, and magmas accumulated in the lower crust, allowing small volumes to rise rapidly to shallow levels along transtensional domains of the regional shear system. A similar model of crustal thickening and shortening before and during porphyry copper emplacement in zones of transtension may also apply to the Miocene-Pliocene giant porphyry copper province of central Chile."

Jan 1, 1999

By Ernest Becker

Golder Associates provided overall radiological direction and assistance to the client in their interactions with the Canadian Nuclear Safety Commission and operational radiation protection services for the remediation of a calciner that had been used to process uranium. The project was somewhat unusual in that the radioactivity from within the calciner room was removed from the site and the cleaned steel recycled. The presence of yellowcake within the process equipment required stringent radiation protection measures. This project was completed successfully with minimal radiation exposures to the workers and the effective protection of the environment.

Aug 1, 2010

By D. Fredlund

The decommissioning of uranium tailings facilities often requires the design of a suitable cover system. In northern climatic environments there is a portion each year that can be considered to be ?inactive? while the remainder of the year can be considered to be ?active?. There are numerous engineering design assumptions required when analyzing both the ?active? and the ?inactive? portions of the year. Cover systems are subjected to complex boundary conditions and nonlinear unsaturated soil properties. The proposed paper describes the steps necessary for the preparation and the analysis of a multi-year climatic database for the design of a cover system in northern environments. The paper also explains how climate can be classified and how observed variations from one year to the next can be taken into consideration in cover design. The results of climatic records at two different sites are used to illustrate conditions that need to be taken into consideration when designing soil cover systems.

Aug 1, 2010

By Tomoya Kawasaki, Tatsuya Motomura, Yutaka Yasuda

Saganoseki Smelter, one of the largest copper producers in Japan, currently operates a single flash smelting furnace to produce 450,000 tons of new copper annually. The smelter used to employ two flash furnaces, and integrated the two into one in 1996. Since then, various improvements to its facilities and technologies have been made to increase productivity. To upgrade the operation efficiency, "stability" was considered a key issue, and the measures were taken to increase the operation and facility reliability. Currently, the furnace is running at a feed rate of 215 DMT/h, while the furnace utilization has been maintained at 97%. This paper outlines recent improvements that have made to increase furnace productivity and efficiency.

Jan 1, 2014

By M. Silver, R. H. McCorkell

The effects of covering materials on radon emanations from uranium mine mill tailings were investigated. Granular materials with air in the spaces allow radon to pass freely. Moist covers of compost or soil decrease radon emanation from tailings. Water-saturated covers were more effective, and freezing the tailings with these covers further decreased radon escape. Water itself is a poor radon barrier probably due to circulation. Plants had no effect on radon emanation through soil. Although radon diffusion through water-saturated powders appears to be very slow and inefficient, about 25% of the radon escaping from the grains in water-saturated tailings diffuse to the surface and emanate when no cover is present. The radon escaping from tailings through covers of water-saturated compost or soil is no more than could be accounted for by radon produced in the covers themselves.

Jan 1, 1987

By Maria D. Mastalerz, Wei Wang, Maria E. Holuszko, Amit Kumar

In this study, the micro-FTIR analysis was used to investigate in-situ surface properties of coal and its components (macerals) and these were directly correlated to the coal hydrophobicity as measured by the contact angle before and after reagent addition to understand the suitability of the reagent for flotation. The micro-FTIR technique can provide a semi-quantitative analysis of the chemical functional groups on coal surface, exactly where the contact angle is being measured. Selected functional groups and their ratios that provide information about aromaticity, the contribution of oxygenated groups, and aliphaticity are used to evaluate the reactivity between reagents and various coal components. The observations made in relation to the susceptibility of some reagents towards certain coal components should lead the way to a smarter way of using process design in terms of reagents selection for coal flotation.

Jan 1, 2017

By D. B. Dreisinger, A. A. Gunaratnam

A pressure oxidation (POX)-hot cure (HC)-lime boil (LB) process is used in industry to recover silver from refractory gold sulfide ores containing minerals such as pyrite and arsenopyrite. Pressure oxidation is used to oxidize minerals and liberate occluded gold particles. As such, iron goes into solution and under acidic and high temperature conditions often precipitates as basic iron sulfate (BFS). BFS consumes excess lime during neutralization prior to cyanidation. Therefore, a hot cure stage is required to re-dissolve BFS back into solution. BFS re-dissolution consumes acid and produces ferric sulfate. In the presence of silver, these conditions favor the slow formation of silver jarosite. Silver jarosite is refractory to cyanidation, and must be broken down prior to cyanidation. This is done in the lime boil to produce a cyanide-soluble silver hydroxide. A study was conducted to investigate parameters that affect the precipitates that form in each stage of the POX-HC-LB process.

Jan 1, 2017

By V. G. Papangelakis, I. Guzman, S. J. Thorpe

Pressure oxidation (POX) leaching has been commercially applied to refractory gold ores since the 1980s. In the process, sulphide material is oxidized and dissolved in order to release the gold encapsulated in the sulphide matrix, making the gold available for further recovery. Redox potential is a significant parameter during POX, however it is only measured ex-situ at atmospheric conditions. In-situ redox potential measurement would provide instant information that allowing adjusting the process parameters accordingly. In the present study, redox potential measurements were performed during POX of sulphide material at high temperatures and high pressures. The working electrode was an Ir electrode combined with a flow-through reference electrode in a novel and robust configuration. Experiments were performed in a 2 L titanium autoclave, at 200–220°C, 50–110 psi oxygen overpressure, and 10–30% solids mass fraction. Temperature and oxygen pressure conditions were selected in order to reflect POX of refractory gold ores. Results show that the Ir electrode is consistent with theory and is able to perform well under these conditions, showing promise as a new in-situ sensor.

Jan 1, 2017

By A. J. Rigby

Anode vessels are often relined with refractory every one to two years and a typical reline time can take between 16-20 days. Modem refractory designs using dense, corrosion resistant brick applied directly to the vessel shell in the high wear areas around and above the tuyeres and at the slagline can yield a lining life of up to 4-5 years before a complete reline is necessary. Installation methods using brick delivery on roller conveyors through an endwall access port and complete anchoring of the brick to allow for lining self-support can take days off the installation time. It is possible, therefore, to reduce the refractory relining period by 50% and increase lining life by 100% compared to typical anode repair schemes. Cu2007

Jan 1, 2007

By Baseer Abdul, Edouard Asselin

Hydrometallurgical leaching of sulfide concentrates of copper and nickel at medium temperature (150°C) produces residues that contain sulfur and iron bearing minerals and phases. During leaching, and depending on various process parameters, iron may be precipitated as hematite, goethite, jarosite or other oxyhydroxides, which may be more or less crystalline. Hematite is the favored precipitate because it is the most environmentally stable and does not ad/absorb as much copper, nickel or other solution constituents during precipitation. However, the low solubility of iron during the medium temperature processing of sulfide ores can favour the formation of poorly crystalline, nano-scale iron oxide/oxyhydroxide phases. In some cases these phases have been positively identified as the metastable ferrihydrite, which transforms into iron oxides such as goethite, hematite and magnetite over time. A better understanding of what may help drive this transformation during leaching would ultimately result in lower valuable metal losses and more stable leach residues. Higher acid concentrations result in increased copper extractions and favor the formation of hematite during concentrate leaching, rather than other metastable phases. Furthermore, commercially available water displacement formula “WD40®” and other novel reagent(s) affect Fe precipitation and sulfur chemistry, leading to very different process outcomes such as improved extractions and larger, more easily separated, sulfur particles.

Jan 1, 2017

By E. Rosseland

Glencore Nikkelverk is operating its Chlorine Leach Process in Kristiansand, Norway, producing nickel, copper and cobalt metals by electrowinning. The copper tankhouse, with an annual capacity of 40 000 tons, is based on traditional technology with copper starting sheets and cast lead anodes. Due to the integration of this copper sulphate process in a nickel chloride refinery, operating conditions are unique. In recent years, operating costs have escalated, and health, safety and environment are top priorities. Test work on a new copper process involving permanent cathodes was therefore initiated in 2007, and a pilot plant was started up in 2012. The objective was to introduce innovative technologies and tailor these to be robust in the Nikkelverk process, to form a basis for a new sustainable copper tankhouse with a high degree of automation. Key learnings from more than 10 years of R&D work is presented, focusing on cathode materials and copper metal deposition including product quality, robotic stripping, coated titanium anodes, electrode contacts and alignment, electrode current monitoring with Hatch HELM tracker technology and acid mist capture using cell hoods with off-gas scrubbing. The new copper tankhouse project was approved in December 2018, and commissioning is planned in 2022. INTRODUCTION The Kristiansand nickel refinery was started up in 1910, processing nickel-copper matte originating from Norwegian mines. It was the first industrial plant in the world to produce nickel by electrolysis using the Hybinette electrorefining process. After roasting to burn off sulphur in the matte, copper was leached and recovered as cathodes by electrowinning with lead anodes. In the first years, the copper cathodes were fire- refined and cast into ingots for sale (Thonstad Sandvik, 2004). The Nikkelverk refinery was acquired by Falconbridge Ltd. in 1929, and since then matte from Sudbury, Canada has been the main feed source. The Hybinette process was in operation until 1975 when conversion to the newly developed Chlorine Leach Process was started (Stensholt, Zachariasen, & Lund, 1986). In this process still used today, nickel and part of the copper in the matte is leached using chlorine gas generated on dimensionally stable anodes in the nickel and cobalt electrowinning tankhouses, as illustrated in Figure 1. The presence of dissolved copper ions in the strong chloride leach solution is essential for effective chlorine absorption and nickel dissolution. To improve copper-nickel separation, slurry from the atmospheric leach is pumped to autoclaves and then to cementation tanks for precipitation of copper as copper sulphide, which is collected in filter presses. The leach residue, also containing the precious metals, goes through a 3-stage wash to remove chlorides before being introduced as a slurry to fluid-bed roasters for sulphur removal. The resulting calcine is then leached in spent electrolyte from the copper electrowinning tankhouse, to dissolve most of the copper and also some nickel, cobalt and other elements. After separation of the leach residue, elements like Bi, Te, As and Ag are removed from the strong copper sulphate solution by reaction with metallic copper in three columns in series filled with cut copper cathodes. The purified solution then passes polishing filters before being mixed with spent electrolyte and returned to the electrowinning cells.

Jan 1, 2019

By H. A. Steane

THIS BRIEF PAPER presents the information available on the use of Dorrclon?is in the middling re-grind unit at the lead-zinc mill of Canadian Exploration Limited. The plant throughput is 1,650 tons per twenty-four hours. The flotation feed is ground to 60 per ?Cent passing through 200 mesh. It contains some composite 11articles of sphalerite in calcite, and these reported either in the final zinc concentrate, thus lowering the grade, or in the tailing, with loss of zinc. The re-grind unit was set up in the zinc flotation circuit to liberate the sphalerite from these middling particles, to raise the grade of concentrate and improve recovery. Grinding through 325 mesh should give substantial liberation of locked sphalerite. The middling regrind unit consists of two Dorrdones and one ballmill arranged as shown in the -accompanying flow-sheet. The Hardinge ball-mill, size 7 ft. x 36 in., was free for this use as a result of recent plant expansion. The two Dorrclones were purchased, and the necessary pumps and pipe lines were installed to complete the regrind unit. The unit has been developed over a period of two years by several steps and various flow schemes until reaching tl1e present flow scheme. These steps are not elaborated here, because the changes were made to determine the best product to work on for flotation metallurgy, and not because of the Domrolone classifying ability.

Jan 1, 1956

By John A. Dresser

Seventy years ago a period of prospecting and mining activity began in the Eastern Townships of Quebec that seems to have been quite equal to that of recent years in the Rouyn field. In the following six or seven years a large amount of work was done over a widespread area. About fifty deposits gave some shipment of ore, from a few tons upwards, and as many as five hundred occurrences of copper were made known in the district by official records. Comparing the scale of commercial undertakings of that time and of the present day, these developments must have occupied quite as large a share of the capital and man-power of the Province as northern Quebec employs today. Working conditions at that time were not very favourable. The country was then only newly opened for settlement, and colonists were few and widely separated. Roads of the class built today were unknown. A single line of railway, the Grand Trunk, crossed the district from east to west. Colonization companies controlled large blocks of land on which they owned mining rights and usually reserved these rights in whole, or in part, when selling the lands. Then, as now, the precious metals belonged to the Crown. Yet the work was not without its successes. One of the first deposits discovered, the Acton, was, for a few years, one of the most profitable producing copper mines of its time. Another, the Eustis mine, has been in almost constant operation ever since, and is now vigorously pushing further development. At least two others, now quiescent, proved profitable operations, and several made considerable production. The manufacture of sulphuric acid in Canada was begun by the founder of the Nichols Company at Capelton, on a deposit that is now being re-developed, after a long and creditable career.

Jan 1, 1928

By Z. D. Hora

Traditionally, industrial minerals in British Columbia comprise about 10 per cent of the combined value of mineral, coal, petroleum and natural gas production. Over the years a wide variety of industrial minerals have been produced in British Columbia, often with a different level of marketing success. For some products such as building stone, common brick or expanded shale, once strong demand gradually disappeared; for others such as asbestos and barite, new discoveries or new industrial activities created demand and new markets. For yet other minerals such as fluorite, talc and perlite, wider use has been prevented by the small size, poor quality or remote locations of the deposits. Bentonite (1926 to 1944-as a by-product from coal mines) Building stone (intermittently since the mid-1800s) Chromite (1918 and 1929) Over the past years, the list of industrial minerals produced has been expanded to include several new commodities: glassgrade silica sand, magnesite, pumice and silica for ferrosilicon and silicon carbide manufacture.

Jan 1, 1984

By Stephen Hardcastle

Presentation Outline ? Introduction ? Mine Ventilation Facts ? Ventilation-on-demand (VOD) ? Sensors/Controls ? Continuing Work ? Conclusions ? Mine ventilation engineering practices were published in 1556 in Agricola?s De Re Metallica (wind sails, bellows, etc.) That was then? This is today? Large fan installations handling >1M cfm

Nov 1, 2011

By A. Proulx

Durant les années 1955 à 1961, plusieurs campagnes d?exploration ont été menées sur la zone Bond dans la partie sud-ouest de l?anneau nord de la carbonatite d?Oka (propriété de Niocan, figure 1). Les zones minéralisées HWM1 et HWM2 sont découvertes à l?ouest de la propriété. Un des forages, le S-60, avait intercepté 80 mètres de minéralisation à 0.71% Nb2O5 à l?est des zones HWM1 et HWM2 mais aucun autres travaux d?exploration n?avaient été réalisés sur cette interception minéralisée. En 1995, Niocan réalise une campagne de forage pour mieux définir la zone minéralisée recoupée par le forage S-60. En 1997, une seconde campagne de forage détermine un tonnage de 14.37 Mt avec une teneur de 0.66 % Nb2O5 pour la zone S-60 (Marcotte et Gagnon, 1997). Le complexe carbonatitique d&apos;Oka se situe à environ 35 km à l?ouest de Montréal sur la rive nord du lac des Deux-Montagnes. Sa formation remonte au Crétacé précoce (entre 117 à 123 Ma). La carbonatite d?Oka fait partie de la suite d&apos;intrusions alcalines que constituent les collines Montérégiennes. Le complexe a une forme allongée (7.2 km par 2.4 km) orientée NO-SE (figure 1). Il est intrusif dans des roches précambriennes constituées d?anorthosites au nord et de gneiss charnokitique au sud (Gold, 1963) appartenant à la Formation de la colline d?Oka. Les gneiss au contact du complexe sont fénitisés sur une épaisseur qui peut atteindre jusqu?à 60 mètres. Les roches carbonatitiques forment la série dominante du complexe et elles sont composées principalement de calcite (> 50 %) à gros grain et parfois rubanées. Les minéraux accessoires les plus communs sont la biotite, le pyroxène, la monticellite, la magnétite, l?apatite, la forstérite, la mélilite, le pyrochlore, la pérovskite, la niocalite, la pyrite et la pyrrhotite (Gold, 1963).

May 1, 2003

By Jim Cooney

Background ?1990s saw massive changes in South African mining industry ?over 100,000 jobs lost as the industry restructured; ?1999 ?Placer Dome purchased a 50% interest in South Deep (WAL), a mine located just outside Johannesburg ?This was the first major post-apartheid foreign investment in the South African mining industry The Situation ?Placer Dome decided to lay off 2560 mineworkers (one third of the workforce) from the South Deep Mine to restore the mine to economic viability. ?Unemployment in South Africa was over 25%, and the retrenched mineworkers had few skills with which to make a living. Policy Context ?Placer Dome was committed to: ?global corporate policy of Sustainable Development, ?demonstrating that its business contributes to the economic and social progress of host jurisdictions. ?Government of South Africa was committed to ?attracting foreign investment to its mining sector with a view to modernizing and enhancing its economic and social viability, ?ameliorating the negative social consequences of structural change without arresting the necessary process of restructuring. ?National Union of Mineworkers was committed to: ?working with the mining industry and the government in implementing a Code of Good Practice on Dismissals and a Social Plan to assist retrenched mineworkers (1999).

May 1, 2006

By A. A. Ruitenberg, S. C. Johnson, L. R. Fyffe

"Several types of stratiform and epigenetic gold deposits have been found in New Brunswick, It is the purpose of this paper to describe and classify the epigenetic deposits and demonstrate their relationship to tectonic evolution. The stratiform deposits are mostly volcanogenic massive sulphide deposits that are described elsewhere (Davies et al., 1985).The auriferous epigenetic deposits include quartz-carbonate veins and stockworks, polymetallic veins, contact metasomatic, porphyry copper and volcanic breccia (epithermal) deposits. These epigenetic deposits are concentrated in major fault zones that define or are close to the boundaries of tectonostratigraphic terranes or terranes and cover sequences. The host rocks of the deposits were subjected to extensive crustal thickening resulting from thrusting and/or high angle reverse faulting.The gold deposits north of the Avalon Terrane occur indilatent structures related to mainly dextral wrench faulting that postdated the episode of crustal thickening. The deposits along the southern margin of the Avalon Terrane occur in structures related to late phase thrusting."

Jan 1, 1990

By M. Medraj, M. A. Arafin, D. P. Turner, P. Bocher

In this study, the kinetics of isothermal solidification during TLP bonding of Inconel 625 and 718 superalloys with nickel based multi-component filler alloy BNi-2 have been studied through a combination of direct experimentation and mathematical modeling in order to determine the effect of process variables and, thus, to optimize the process. The predicted isothermal solidification completion times from the boron diffusion model and migrating solid/liquid interface model were in good agreement with the experimentally determined values and, they were found to be significantly less than those of other nickel superalloys with different nickel based filler alloys. Further, significant reduction of holding time was observed with increasing bonding temperature and with decreasing joint gap. No significant grain growth in the base metals has been observed in the temperature range being investigated (1325 - 1394K).

Jan 1, 2006