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By G. C. Laurence

"This paper discusses the hazards and extensive precautions taken in Canadian uranium mines, concentrating plants and processing plants. It also outlines Canadian policy regarding the control of the sale and distribution of uranium and other nuclear materials.OVER THIRTY YEARS AGO, I spoke to The Canadian Institute of Mining and Metallurgy here in Montreal about radioactivity and its dangers. I must have made quite an impression thirty odd years ago, because now you have asked me to do it again. Of course, the picture has changed. Then they were mining uranium ore, recovering the radium from it and throwing away the uranium. Now they are still mining uranium ore, but are throwing the radium out on the tailings dumps. Thirty years ago, most people did not know what ""radioactivity"" meant. Nowadays, they have beard that it is dangerous, and some of them, recently, be-came worried about the radium in the tailings dumps and what becomes of it."

Jan 1, 1969

By W. A. Jankola

Teck Cominco Metals Ltd. operates an integrated zinc-lead smelter at Trail, British Columbia, Canada. The zinc circuit comprises three parallel operations: conventional fluid-bed roasting, direct zinc pressure leaching of concentrates and atmospheric leaching of zinc oxide fume recycled from the lead smelter. The products from these three areas are combined in the main leaching plant where they undergo iron purification. Unlike most leaching circuits, the leach process in Trail begins with an acid leach and is followed by a neutral leach. An evaluation was undertaken to determine if the process at Trail could be improved by converting to the conventional neutral leaching process with a subsequent acid leach of the residues. This paper explores the results of these tests and the implications for Trail Operations.

Jan 1, 2006

By C. Cutts, K. Wheatley

The Dragon Lake Zone (uranium prospect) comprises a N160º trending vein that is approximately 110 m long, up to 5 m wide and from 1 to 40 m high. The zone is mostly within altered sandstone of the Fair Point Formation, the basal unit of the Paleoproterozoic Athabasca Group, but it also extends downward (up to 3.5 m) into basement rocks that occupy the northerly trending Maybelle River Shear Zone (MRSZ). This subvertical shear zone separates graphitic paragneiss and weakly deformed granitoid rocks to the east from non-graphitic paragneiss and foliated granitoid rocks to the west. The Dragon Lake Zone cuts across both the MRSZ and N060º-N070º-trending cross-faults that offset the shear zone but not the mineralized vein, which contains values up to 54.5% U over 50 cm core length. Strong chloritization occurs in graphitic paragneiss and sandstone adjacent to mineralization. Silica was depleted from the basement rocks and redeposited at the borders of the 5-15-m-wide alteration zone, as well as within overlying sandstone of the Manitou Falls Formation. There are minimal alteration effects in the overlying Lazenby Lake Formation. Geochemistry shows that the alteration zone in the Fair Point Formation is highly anomalous in metals, most notably in Ni, As, U, Pb, Co, and B. Clay within this zone is illitic and Fe-rich chlorite is also present. Brittle deformation is not as widespread or as well developed in the Fair Point Formation as it is in the overlying Manitou Falls Formation, which is extensively brecciated and contains some anomalous metal values.

Jan 1, 2013

By S. C. Livanou, S. P. Tampouris, E. N. Zevgolis

In ferronickel (Fe-Ni) production from oxidized nickeliferous ores, mechanical losses of ferronickel in the slag are reduced by magnetic separation. Slag from the electric furnaces (E/Fs) contains 0.16% Ni. Its magnetic separation gave a pre-concentrate with 0.76% Ni, weighing approximately 6.5% of the feed. Nickel recovery was 29.7%. This pre-concentrate was then treated in a second (concentration) plant. Concentration treatment involves screening, crushing and magnetic separation. A pre-concentrate with 0.76% Ni gave a magnetic concentrate with 2.58% Ni and a non¬magnetic part with 0.35% Ni. Smelting of the non-magnetic part without the addition of a reduction agent in a laboratory electric arc furnace, gave a ferronickel alloy with approximately 20% Ni and a slag with 0.16% Ni.

Jan 1, 2005

By Yongjun Peng, Yufan Mu, Rolf A. Lauten

"Chalcopyrite, a major source of copper, is commonly found associated with iron sulfides, particularly pyrite. The separation of chalcopyrite and pyrite by flotation is difficult due to the galvanic interactions between pyrite and chalcopyrite during grinding and flotation. Galvanic interactions may cause oxidation and dissolution of chalcopyrite, copper activation of pyrite and the formation of hydrophilic iron hydroxide coating. The overall effect may change the floatability of the components and lead to the misplacement of pyrite into chalcopyrite concentrate. The objective of this study was to investigate the effect of lignosulfonate-based biopolymers on the depression of pyrite in the flotation of chalcopyrite with xanthate as collector and the mechanism responsible for the selective depression of pyrite. The flotation results showed that biopolymers depressed the flotation of both copper-activated pyrite and chalcopyrite in single mineral flotation although to different extents. In the flotation of mixed mineral systems, biopolymers significantly depressed pyrite flotation but had a less influence on chalcopyrite flotation. The selective depression of pyrite by biopolymers was due to the preferential adsorption of biopolymers on copper-activated pyrite surface. Galvanic interactions between pyrite and chalcopyrite surfaces promoted copper activation on pyrite. Presence of cuprous ions on pyrite surface favored biopolymer adsorption by the formation of a complex between the cuprous ions and biopolymer molecules. The same galvanic interactions also facilitated chalcopyrite oxidation leading to the formation of hydrophobic polysulfide that enhanced the hydrophobicity on chalcopyrite surface. The biopolymer structure controlled the depression effect. The results showed that the biodegradable biopolymers are promising depressants for pyrite.INTRODUCTIONCopper sulfide minerals, such as chalcopyrite (CuFeS2), bornite (Cu5FeS4), chalcocite (Cu2S) and covellite (CuS), are the major mineral source for copper. They are often found finely interlocked with iron sulfides, especially pyrite (FeS2) (Owusu, Brito e Abreu, Skinner, Addai-Mensah, & Zanin, 2014). Pyrite, as the most abundant sulfide mineral, is perceived as gangue in most cases and should be removed from the associated sulfides to minimize its contamination of the copper concentrate (Owusu, Addai-Mensah, Fornasiero, & Zanin, 2013; Wang & Forssberg, 1991). The commonly used strategy to remove pyrite is flotation (Wang & Forssberg, 1991)."

Jan 1, 2016

By Rob Kelso

What is a Lunabot? ?Robot Controlled Remotely or Autonomously ?Visual and Auditory Isolation from Operator ?Excavates Black Point 1 (BP-1) Simulant ?Weight Limit - 80 kg ?Dimension Limits - 1.5m width x .75m length x .75m height ?Designed, Built and Tested by University Student Teams

May 1, 2013

By Greg Gosson

"Early efforts to develop formal reporting systems to quantify and classify mineral deposits date back over 100 years. (e.g. Hoover 1909: “Proved, Probable, Prospective Ore”). This was at first driven by mine operators’ need for reliable estimates of what their mines could produce. Disruption of transportation routes by world wars prompted western governments to recognize the need for assessments of strategic sources of metals and minerals that could support domestic industry during times of crisis. Categories were created to quantify mineral potential which were additional to those of mine reserves. Terms such as hypothetical and undiscovered resources entered the lexicon. Capital markets serving the mining industry were traumatized during the latter part of the 20th century by undisciplined and fraudulent disclosure by exploration companies of mineral deposit potential. Government securities regulators pressed for the development of credible reporting codes (e.g. SEC Industry Guide 7: 1981; JORC 1989; SAMREC 1994, CIM 2000). Representative organizations from the major western mining countries generally agreed that there should only be three categories of mineral resources (measured, indicated, and inferred) and two categories of mineral reserves (proven and probable). This was formalized in 1997 with the “Denver Accord”. Acceptance of the standard terminology may have been the easy part, because the challenge for the 21st century is to get general industry acceptance and agreement of the principles behind the definitions of each category. There has been noticeable movement towards this objective in the last few years. This is reflected in part in the updated reporting codes by JORC 2004, CIM 2005; SAMREC 2007; SME 2007; and PERC 2008, and the development of the CRIRSCO International Reporting Template 2007."

Jan 1, 2003

By Denis Racicot

"L'Abitibi québécois a produit essentiellement de l’or, du cuivre, du zinc et de I' argent, ainsi que de faibles quantités de nickel, de plomb, de molybdène, de bismuth, de lithium, de fer et d’amiante. Depuis l’ouverture de la mine Horne en 1927, cent-cinquante mines ont contribué à la production de 1 420 tonnes d’or de 4,1 millions de tonnes de cuivre et de 4,7 millions de tonnes de zinc. Les productions minières annuelles ont été d'importance variable: des records de production ont été établis en 1955 pour I' or avec 35 tonnes et, vers 1965, pour le cuivre, le zinc et la quantile globale de minerai extrait avec respectivement 130,000, 275 000 et 13 millions de tonnes. Deux dépressions généralisées ont eu lieu, l’une vers 1946 et l'autre, a lafin des années soixante-dix. Des ralentissements de la production ont été observes pour le cuivre en 1953 et le zinc en 1959. Depuis le debut des années quatre-vingt. I' or et, de façon plus irreguliere, le zinc sont en progression, landis que le cuivre, malgre une hausse en 1983. pour suit son dec/in.La teneur de récupération des mines d’or est demeurée régulière et n’a subi qu’une faible diminution au cours des quarante dernières années. Célie du cuivre a diminué d'environ 50% dans la même période, landis que celle du zinc a subi d’import antes variations, aussi bien positives que négatives. Près des trois quarts des mines d'or ont une durée de vie inférieure à 12 ans et la distribution des tonnages de minerai extrait montre un maximum pour la classe de 100 000 à 1 million de tonnes. Du cote des mines de métaux de base, la durée de vie est plus étalée et les volumes de minerai ont une occurrence maximale dans la classe de 1 à 10 millions de tonnes.Concernant la distribution géographique de la production minière dans l'Abitibi québécois, le camp minier de Rouyn-Noranda vient en tête pour l’extraction de minerai et la production d’or et de cuivre. L’est sui vi par le camp de Val d'Or pour le minerai et l’or, landis que le camp de Chapais-Chibougamau occupe la deuxième place pour le cuivre avec une production équivalence a 60% de celle de Rouyn-Noranda. Le camp de Cadillac-Malartic suit de tres pres celui de Val d'Or pour ce qui est de I' or. Finalement, dans le casdu zinc, le camp minier de Joutel-Matagami domine largement avec une production qui a connu un développement accélère depuis 1963. Une analyse pré liminaire de ces données indique qu' i/ subsiste unpotentiel encore élevé de production d'or, décuivre et de zinc dans I' Abitibi québécois. ABSTRACTThe Quebec portion of the Abitibi belt has essentially produced gold, copper, zinc and silver, as well as some small quantities of nickel, lead, molybdenum, bismuth, lithium, iron and asbestos. Since the opening of the Horne mine in 1927, one hundred and fifty mines have produced 1420 tons of gold, 4,1 millions tons of copper and4,7 millions tons of zinc. Annual mine production has fluctuated: production records were established in 1955 for gold with 35 tons, and around 1965 for all extracted ore copper and zinc with respectively 13 millions, 130 000 and 275 000 tons. Two main recessions have occurred, the first around 1946 and the second during the late seventies. Cut backs in copper and zinc production occurred in 1953 and1959. Since the beginning of the eighties, gold production and to a lesser extent zinc production have been in progression. Except for a small jump in 1983, copper production is still declining.The average recuperation grade of gold mines has been quite steady and has only slightly diminished in the past forty years. The average copper recuperation grade was halved during the same time interval. For zinc there have been important ups and downs. At least three quarters of gold mines have an average lifespan of 12 years the tonnage distribution shows a peak in the 100 000 to 1 million tons class. Base metals mines show a more widespread life expectancy and have a tonnage peak in the 1 to 10 millions tons range"

Jan 1, 1990

By Catharine E. G. Farrow, David H. Watkinson

The Ni-rich Epidote Zone of the Fraser Mine at Sudbury is characterized by alteration assemblages rich in epidote, actinolite and magnetite which are roughly concentrically zoned and up to hundreds of meters in length. These zones form discrete areas within the igneous Footwall Breccia below the Sudbury Igneous Complex. The assemblages grade from epidotized Footwall Breccia matrix,through actinolite-bearing rocks with few vestiges of original Footwall Breccia textures, into the most intensely altered rock, a magnetite-rich facies. Pentlandite, pyrrhotite and pyrite are the dominant sulfdeminerals; chalcopyrite is minor. The strongest geochemical differences compared to original Footwall Breccia occur where epidote and actinolite dominate the alteration assemblage (EPDZact facies). The most intense alteration facies are typifed by low Cu/(Cu+Ni) values of <0.1. Strong positive correlations exist between Ni and Co, Cu and Au, and among Ir, Os, Ru and Rh. Chondrite-normalized Ni - PGE -Au - Cu plots display an overall increase in all elements from the least to the most intensely altered facies except for Au and Cu. As the proportion of actinolite increases in the EPDZact facies, the chondrite-normalized profles fatten considerably due to low Au and Cu contents. Abundances of Ni, Ir, Ru and Rhalmost ubiquitously increase with degree of alteration. In contrast, Cu, Zn, Ag and Au contents are low in almost all facies. It is suggested that saline hydrothermal fluids moved through the Epidote Zone formation and became more oxidized as they reacted with the Footwall Breccia and with footwall units, including ultramafic rocks. As this trend continued, magnetite-rich zones eventually developed. The occurrence of calcite locally in these magnetite-rich zones suggests that the pH of the fluid increased, causing Cu solubility to drop as activity in the hydrothermal system waned. Sudden changes in fluid composition such as this may have been due to an influx of fluid from bounding ultramafic rocks. Hydrothermal activity was focused along the margins of footwall ultramafic units. Individual hydrother-mal cells may have formed in the Footwall Breccia along pre-existing structures or sulfde concentrations. Metals may have been scavenged from sulfide-bearing Footwall Breccia and possibly Sublayer rocks. Nickel and some PGE were deposited in the Epidote Zone, whereas Cu, Au and Ag continued out-ward into the footwall where they were deposited as Cu-rich footwall veins. Copyright © 1996 Canadian Institute of Mining, Metallurgy and Petroleum.

Jan 1, 1996

By Catharine E. G. Farrow, David H. Watkinson

Abstract-The Ni-rich Epidote Zone of the Fraser Mine at Sudbury is characterized by alteration assemblages rich in epidote, actinolite and magnetite which are roughly concentrically zoned and up to hundreds of meters in length. These zones form discrete areas within the igneous Footwall Breccia below the Sudbury Igneous Complex. The assemblages grade from epidotized Footwall Breccia matrix, through actinolite-bearing rocks with few vestiges of original Footwall Breccia textures, into the most intensely altered rock, a magnetite-rich facies. Pentlandite, pyrrhotite and pyrite are the dominant sulfide minerals; chalcopyrite is minor. The strongest geochemical differences compared to original Footwall Breccia occur where epidote and actinolite dominate the alteration assemblage (EPDZact facies). The most intense alteration facies are typified by low Cu/(Cu+Ni) values of <0.1. Strong positive correlations exist between Ni and Co, Cu and Au, and among Ir, Os, Ru and Rh. Chondrite-normalized Ni - PGE - Au - Cu plots display an overall increase in all elements from the least to the most intensely altered facies except for Au and Cu. As the proportion of actinolite increases in the EPDZact facies, the chondrite-normalized profiles flatten considerably due to low Au and Cu contents. Abundances of Ni, Ir, Ru and Rh almost ubiquitously increase with degree of alteration. In contrast, Cu, Zn, Ag and Au contents are low in almost all facies. It is suggested that saline hydrothermal fluids moved through the Epidote Zone formation and became more oxidized as they reacted with the Footwall Breccia and with footwall units, including ultramafic rocks. As this trend continued, magnetite-rich zones eventually developed. The occurrence of calcite locally in these magnetite-rich zones suggests that the pH of the fluid increased, causing Cu solubility to drop as activity in the hydrothermal system waned. Sudden changes in fluid composition such as this may have been due to an influx of fluid from bounding ultramafic rocks. Hydrothermal activity was focused along the margins of footwall ultramafic units. Individual hydrothermal cells may have formed in the Footwall Breccia along pre-existing structures or sulfide concentrations. Metals may have been scavenged from sulfide-bearing Footwall Breccia and possibly Sublayer rocks. Nickel and some PGE were deposited in the Epidote Zone, whereas Cu, Au and Ag continued outward into the footwall where they were deposited as Cu-rich footwall veins.

Jan 1, 1996

By F. L. Thompson

MAN has been using lubricants of one type or another for at least four thousand years, and probably for a much longer period. We have learned from the inner wall of the tomb of Tehuti-Hetep, on which is a decoration illustrating the method of moving a great stone statue, that as early as 1650 B.C. lubricants were used to facilitate the movement of heavy loads. The Egyptians had available nearly every animal oil and fat, as well as at least thirteen vegetable oils, of our time, all used for food products and in the arts. Examination of the deposit on the axle of a chariot from an Egyptian tomb of 1400 B.C. showed it to consist of animal fat, quartz, sand, iron, and compounds of aluminium and lime-indicating a manufactured lime-soap grease made with lime-soap and possibly tallow. This would not be a bad lubricant for the axles of chariots which had to travel over sandy soil in hot weather. As to the method of grease application, it is remarkable that, from the time wheels were first used in the far distant past up to the present day, no one has ever thought it necessary to design a seal to keep the lubricant in and the dirt out. While time certainly marches on, we have today, in waggons throughout the world, exactly the same form of lubrication as was used in the earliest chariots. From the early days of the chariot until shortly before 1800 A.D. (when the steam engine was introduced), the main heavy equipment required for mining purposes, for machines of war, etc., was made of wood. The bearings were rough, but usually they had metal in the lower half. Light machinery was made of bronze, brass, or iron. Large clearances and poor alignment, plus the fact that speeds were much below present-day demands, combined to provide conditions that were quite satisfactorily met by the lubricants available. These were often produced locally by the machine operator. In northern countries, lard oil, prepared from the fat of hogs, was the universal lubricant employed in machine shop, as a belt and leather dressing, and for cutting operations. Sperm oils were used for light machinery, whereas beef and mutton tallow were more generally employed for the largest bearings. For the early steam cylinders, a slug of heated beef tallow was injected wherever the cylinders gruntingly complained of a lack of lubricant. Southern countries, however, resorted to the use of vegetable oils-olive, cocoanut, etc.

Jan 1, 1940

During heap leaching of secondary copper sulphide ores operated at low heap temperatures and high levels of leach solution salinity, copper recovery is usually unsatisfactory, due to a slow chemical and bacteriological leaching of the covellite minerals either formed from leaching of chalcocite or naturally occurring in ores. A laboratory test program was conducted to investigate the effect of leach solution temperature in the range of 20 to 50°C on copper extraction during stirred reactor, bottle roll, and short column leaching of fresh or heap leached secondary copper sulphide ores. It was demonstrated that increasing heap temperature is an effective approach for improving recovery of copper from secondary copper sulphide ores. A review of the technologies available for heating heap leach solution or decreasing solution salinity to improve copper recovery from secondary sulphide ore indicates that an integration of copper concentrate pressure leaching with heap leaching is potentially a cost-effective approach. A copper flotation concentrate sample was tested through pressure oxidation with the use of heap leach solutions of varying strengths for the repulping of the concentrate in order to examine its effect on pressure oxidation performance. The test results indicate that use of heap leach solution of high salinity in the pressure oxidation process does not cause a negative impact on the process performance for copper extraction, sulphide oxidation, and recovery of gold (if present) from pressure leach residue, and has additional advantages of removing the bacterially inhibitory aluminum from heap leach solution and generating more acid and ferric iron in the pregnant leach solution. A flowsheet configuration for full integration of the copper concentrate pressure oxidation with heap leaching of secondary copper sulphide ore is proposed and discussed.

Jan 1, 2014

By W. G. Robinson

"MINING is one of Canada's most important industries and exploration is the life-blood of this dynamic and exciting business. The health and growth of the mining industry of tomorrow depends on the effort and thought that go into exploration today. The Members of the Geology Division of the C.I.M. are directly concerned with exploration, and it is fitting that this Division should periodically sponsor reviews of the thoughts and practices of the exploration com-munity. Accordingly, we have invited seven leading authorities to contribute papers dealing with specialized aspects of this field.Exploration is a science, or art if you will, that is constantly changing in keeping with our expanding knowledge of geology and technology. It started with the old-time prospectors who searched the wilds for exposures of ore, and made finds that developed into some of our most important mining camps. As more discoveries were made, they were able to relate certain types of deposits with particular geological conditions, laying the foundation for modern concepts of economic geology. The mapping by the early field parties lacked detail and usually served to outline the ""greenstone"" areas considered favourable for prospecting. More de-tailed studies through the years by government and company geologists led to new thoughts on the origin, emplacement and geological control of orebodies. The continuing diversity of opinion on these subjects indicates a need for further research, but each year sees an increase in our reserves of factual information."

Jan 1, 1967

By A. G. Darnley

"The Geological Survey of Canada is devoting consider-able effort to finding ways to make airborne radiometric measurements both quantitative and reproducible. Equipment has been designed by Atomic Energy of Canada Ltd. to provide high count rates in order to minimize statistical uncertainty, this being essential to justify applying terrain clearance and Compton scattering corrections to the data. Correction factors have been determined experimentally and can be applied automatically. Considerable ground work has been undertaken in parallel with equip-ment development in order to determine field parameters.Two airborne gamma-ray spectrometers are described. One is based on three 5-by 5-inch Nal(Tl) detector crystals and is used in a helicopter; the other employs twelve 9-by 9-inch detectors and is used from a Skyvan aircraft. The former is being used to investigate the range of radiometric response from specific rock types, and for the correlation of ground and air measurements; the latter has completed initial trials and will be commencing experimental surveys during 1969.Results are given to show the comparative sensitivities of the various detector sizes, and operational requirements for a gamma-ray spectrometer survey are discussed briefly."

Jan 1, 1970

By M. Lahtinen, B. Saxén, M. Latva-Kokko

The conventional jarosite precipitation process with neutralization by zinc calcine is widely utilized in the zinc industry. However, it has a significant drawback of causing losses of valuable metals like zinc, lead and silver to the jarosite. This comes mainly from the content of these metals in the calcine used for neutralization. As the zinc plants today want to maximize metal recoveries and minimize the amount of residues, this matter has become more and more relevant for zinc producers. Outotec developed and patented in early 2000 an improved version of the jarosite precipitation process in which the need for neutralization can be minimized, thus the metal losses to the jarosite also can be minimized. At the same time, the iron content of the jarosite increases and the amount of produced jarosite is smaller. The main feature of this process is to start the precipitation from ferrous iron after having reduced all the iron by zinc concentrate in a separate step before jarosite precipitation. Iron is then oxidised back to the ferric form simultaneously with jarosite precipitation. By this method, the formation of sulphuric acid is only half that compared to the conventional method and the need for calcine for neutralization can be avoided. High mixing and oxygen dispersion capability are needed in this jarosite precipitation process. Such capabilities are found in the Outotec OKTOP® reactor series. High performance reactors are not only needed to generate high quality precipitates, but also to maximize oxygen utilization; i.e., to minimize operation costs. Outotec’s latest development in this area is the OKTOP® plant product in which not only the reactors, but also all the accessories are designed, manufactured and delivered by Outotec. One responsible supplier ensures efficient and fast delivery and can provide mechanical and performance guarantees for the entire plant unit.

Jan 1, 2016

By J. Kochhar, Robert G. Cooper

"The Cape Breton Development Corporation is a federal Crown corporation which was formed in 1968. Initially, the Corporation had two divisions - the Industrial Development Division, whose purpose was to stimulate Cape Breton Island&apos;s economy, and the Coal Division with a mandate to phase out the operating coal mines. However, that strategy changed in the early 1970s with the Middle East oil crisis. As a result of that crisis, Nova Scotia Power Corporation adopted an ""off oil"" policy. Today, approximately 700/0 of Nova Scotia power needs are met by generation of electricity from coal. Therefore, since the early 1970s, emphasis has been on the rehabilitation of the Cape Breton coal mining business with the opening of three new mines.Today, Devco is solely a coal mining company which employs 3300 people.Physical DescriptionThe mines operate in the Sydney coal field which is located on the eastern tip of Cape Breton. The Corporation leases the deposit from the province of Nova Scotia and its leases cover all coal from the outcrop to the 4000 ft depth. The seams outcrop along the shoreline and dip beneath the ocean floor at dips varying between 5% and 100%.There are eleven seams, of which three - the Harbour, Phalen, and Hub - have been extensively mined."

Jan 1, 1990

As part of the Australian Mineral Industries Research Association (AMIRA) P9 project, methods of characterising both the ore and the machines in flotation circuits have matured considerably over the past 15 years. Machine characteristics include gas dispersion measurements, such as bubble size, gas hold-up and superficial gas velocity. Ores can be characterised in terms of floatability parameters on a size and mineral basis. Measurements have been performed on various copper plants in many countries around the world over the last 5 years. This paper outlines the cell and ore floatability characteristics of each copper plant and provides a discussion on the differences between these plants. In general, most porphyry copper ore bodies are processed at high tonnage through several parallel banks of cells at each stage of flotation. The floatability parameters of these copper ores are very similar in terms of rate of flotation and proportion of fast, slow and non-floating material. The cell characteristics are also similar, with superficial gas velocity, bubble sizes, and gas hold-up values being of similar magnitude. Investigation of the similarities and differences of the modem copper flotation circuits has allowed an increase in understanding of the particularities of copper flotation. Comparison against other copper circuits provides a benchmark and opportunities for future optimisation.

Jan 1, 2007

By Michael Chender

Emerging Equity Sources ? Larger IPOs ? China Inc. ? Other sovereign wealth funds ? New funds and higher allocations ? Private equity

May 1, 2010

By R. Jacobs, R. E. L. Pobe

The Moab Khotsong Metallurgical Complex comprises a gold recovery circuit (Noligwa Gold Plant) and a uranium recovery circuit (South Uranium Plant). The metallurgical complex employs the reverse leach technology for the recovery of uranium; specifically, uranium extraction prior to gold using acid leaching processing. The inherent uranium species in the ore are uraninite, coffinite and brannerite. The slurry that has been subjected to the uranium leach is further subjected to solid-liquid separation to separate the uranium in solution through counter-current decantation and the solids (solids carrying all the gold), which are repulped and returned to the gold plant for gold processing. The uranium leaching process is critical to the uranium playing a pivotal role as a value adding by-product to the gold operation. The benefit of adopting this reverse leach process, for improved gold recovery, is that it exposes gold particles occluded within the uranium matrices and avails them for cyanidation. However, the drive for operational efficiency in uranium extraction must be weighed against the incremental operating cost against the backdrop of depressed spot uranium market prices. Over the years, efforts were directed at maintaining the benefit of extracting uranium to enhance gold recovery and simultaneously, optimizing the operating cost model for the uranium operation to remain relevant to the gold operation. The aim of this paper and the corresponding presentation is to give account of the uranium processing optimization journey embarked on over the years; namely, the operational trade-offs made in the process of ensuring that uranium continues to add value to the gold operation. These challenges were faced while striking a fine balance between processing cost and operational efficiencies against the prevailing depressed uranium spot market prices. Mineralogical- and laboratory tests conducted form the support basis for the results and observations articulated in the paper.

Jan 1, 2020

By G. Gabra, M. Nagamori, J. J. Panneton

"RESUMELa calcination contrôlée de 10 serpentine permet de produire de 10 magnésie active. Le degré de I&apos;activation est mesure par 10 solubilité du magnésium dans les acides faibles tel que I&apos;acide acétique, La serpentine contenue dans les résidus d&apos;amiante du Québec peut donc être activée par calcination. Le teneur en magnésie active des rejets d&apos;amiante calcinés est fonction de divers paramètres: température, temps de calcination, granulométrie, etc. Les rejets d&apos;amiante de différentes provenances démontrent des comportements thermochimiques différents qui sont étudiés dans Ie présent travail au moyen d&apos;ATD, de TG, de la diffraction des rayons X et de la lixivation par l&apos;acide acétique. On constate qu&apos;un maximum d&apos;environ 80% de la magnésie totale peut être activé dans certains rejets d&apos;amiante du Québec et Ie degré d&apos;activation dépend de la provenance.vIntroductionOn sait depuis longtemps que la serpentine, Mg3Si2O5(OH)4, un silicate hydroxylé de magnésium, devient amorphe lorsqu&apos;elle perd de I&apos;eau d&apos;hydratation entre 600 et 700 °C. La serpentine ainsi calcinée est alors dissociée en magnésie et en silice. Cette magnésie, dite active, est soluble dans un acide faible ou même dans les solutions de sels d&apos;ammonium.Plusieurs precédés chimiques ont été proposés afin d&apos;extraire sous forme de composés magnésiens la magnésie de la serpentine. La plupart de ces procédés comportent une activation par calcination de la serpentine préalablement à une Iixiviation par un acide ou par une solution d&apos;un sel d&apos;ammonium.Malgré la contamination par Ie fer et par d&apos;autres éléments, les compositions chimiques des rejets de différentes mines d &apos;amiante du Québec, présentées au tableau 1, sont très proches de la serpentine typique. Puisque Ie degré d&apos;activation de la magnésie varie grandement d&apos;une serpentine à I&apos;autre lors de la calcination, la première étape de la recherche sur la transformation chimique des rejets d&apos;amiante du Québec se résume à une étude de leurs comportements thermochimiques."

Jan 1, 1982