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By Robert G. Boutilier

So far, most social performance monitoring systems have not gone beyond listing the impacts on various stakeholders. Executives have had to rely on intuition to devise interventions that would improve the impacts. This paper describes a survey process, known as the Stakeholder 360 (S360), which eliminates much of the guesswork. The paper reviews key studies showing that raising the levels of communication, trust, and common vision among stakeholders leads to the acquisition of the resources needed to improve the socio-economic situation. Therefore, the Stakeholder 360 measures the levels of these three factors in the relationships between a company and its stakeholders, and among the stakeholders themselves. In a validation study at a gold mine in rural Papua New Guinea, the S360 produced a socio-political ?roadmap? that showed management and stakeholders alike which relationships need more communication, trust, or common goals/vision. Management used the findings to create alliances that helped the government move forward on a regulatory regime for the mine closure. The community used the findings to focus its planning for life after the closure. An S360 survey conducted six months later revealed a decline in dependence on the mine and an overall increase in levels of mutual understanding.

May 1, 2002

By D. Lunt

Telfer bulk concentrates typically contain 8% chalcopyrite, 8% chalcocite, 45% pyrite and 80-120 g/t gold. Although very high copper and gold recoveries can be obtained by subjecting the concentrate to a "conventional" high temperature pressure oxidation step followed by copper recovery by solvent extraction and electrowinning, and cyanidation of the leach residue for gold recovery, the cost of lime required for neutralisation and power for oxygen generation was such that the process was uneconomic in terms of operating costs. The challenge therefore was to develop an alternative flowsheet that maximised copper and gold recovery in which the reagent costs were commercially attractive. An additional objective was to reduce the capital cost so that the overall NPV and IRR values would enhance the economic viability of the total project. Following a series of batch and locked cycle testwork programs, supported by Metsim modelling, it was established that the same high levels of overall copper and gold recoveries can be obtained by use of a novel two-stage split leaching circuit in which the chalcocite component is leached in a low temperature (90-110°C) circuit with the chalcopyrite component treated in a high temperature (220-250°C) circuit. This split circuit has a number of advantages, including minimising the required capacity of the high temperature autoclave, as well as reducing the overall lime consumption and simplifying the total process water balance. The paper outlines the basis for the development of the flowsheet and discusses the integration of the leaching stages into the overall circuit.

Jan 1, 2004

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

Energy benchmarking is widely applied across industries to determine the potential to improve energy performance. Unlike the many technologies for which energy benchmarks and efficiency rating systems are already in maturity, benchmarking of mining processes is still in its infancy. Benchmarking energy usage in mining operations, where energy costs are high and represent a significant portion of overall operating expenses, is challenging due to the uniqueness of each mining operation. Mines vary in terms of geology, geographic setting, ore body geometry, mineralogy which impact the mining method, material handling, processing and waste management. In order to gauge the opportunity for reducing the energy intensity of individual operations and also to compare the energy performance of operations on a global scale, the deployment of new benchmarking methodologies, models and frameworks is necessary. As a step towards the establishment of an accurate framework for benchmarking the energy consumption of mining operations, comminution, one of the more energy intensive mining sub-processes, was selected as the focus of a new energy benchmarking method. The methodologies and processes used to onset fragmentation in a rock mass to the crushing or grinding of rock to a size that is suitable for economic extraction are predominantly dependent on the ore properties. For this reason, site specific factors, such as the size reduction requirements and ore hardness were included in an energy benchmark model so that the energy performance of comminution processes at different operations could be normalized and compared on a global scale. Single particle compression breakage has been identified by several prominent researchers in the field of comminution as the upper limit of energy utilization in size reduction processes. For this reason single particle compression breakage was proposed as the basis of a work index for ores to be used as an input for the benchmark model. Overall, the new method showed that the energy benchmark for mineral comminution can be normalized and subsequently compared for a range of mining operations once the ore hardness has been appropriately characterized.

Aug 1, 2013

By B. Caldwell

"The CompanyCardinal River Coals is jointly owned by Luscar Ltd. and the Consolidated Coal Company of Canada (Consol). The Luscar mine is operated by Luscar Ltd. and is located 40 km south of Hinton near Cadomin, Alberta (Fig. 1). The plant sits on the old townsite of Luscar, Alberta, which was founded in order to develop the coal in 1912 (Fig. 2). Initially, the coal was mined by Luscar Ltd. for heating and steam generation and used quite heavily by the railways for their steam locomotives. In 1955, the mine was decommissioned as the demand for coal for tl1ese purposes had dropped off. In 1969, the mine was re-established by Cardinal River to provide metallurgical coking coal for its customers in Japan. The coal is mined from the 13m thick Jewel Seam by open pit methods at a 10 to 1 stripping ratio. The run-of-mine coal is then cleaned to meet customer demands.The PlantThe clean coal preparation facilities at Cardinal River were extended in 1980 in order to increase the feed rate from 450 t/h to 800 t/h. The extension is a separate plant which can be operated on its own or in parallel with the old plant. In addition, modifications have been made to the fine coal circuit (hydrocyclones added), the coarse refuse circuit, (refuse bucks replaced by a refuse conveyor which backfills a pit), and the fine refuse circuit (solid bowl refuse centrifuges, refuse classifying cyclones, and hydra-rake thickener no longer utilized) since the plant was built in 1969. The plant production of 3 M t per year with a yield of 78% is achieved by first screening and breaking the run-of-mine material to a top size of 1 ½ in. The feed is then slurried, sized, and processed in three different washing circuits. The washed coal is mechanically dewatered, thermally dried, and then stored in a 14 500 t capacity silo or on a 300 000 t stockpile. The fine refuse is thickened and pumped to the same pit to which the coarse refuse is being conveyed"

Jan 1, 2000

By G. Roy, D. R. Lentz, A. O. Wills

"Abstract - Diamond-drill hole DDH-B357, located 1.5 km north of the Brunswick No. 6 Zn-Pb- Cu-Ag volcanic-sediment-hosted massive sulfide (VSHMS) deposit, intersects three exhalative horizons within variably altered felsic volcanic rocks of the Nepisiguit Falls and Flat Landing Brook formations. These three petrographically indistinguishable iron formation intervals (Fe2O3T = 21.4 wt.%) likely represent cogenetic hydrothermal sedimentary units because they display a common geochemical signature: Fe2O3T = 42.9 ± 10.5 wt.%, MnO = 5.4 ± 3.1 wt.%, elevated base metal values (Zn+Pb = 1999 ± 1091 ppm), strong enrichment in additional exhalative components (CaO = 5.3 ± 3.9 wt.%; P2O5 = 1.43 ± 1.00 wt.%), oxidized signature (Fe/Mn = 10 ± 6), as well as a common immobile element signature (Zr/TiO2 = 0.025 ± 0.007) representative of a pelagic source. The calc-alkaline to transitional host volcanic rocks can be discriminated by Zr/TiO2, and to a lesser extent by Th/Nb: Nepisiguit Falls Formation: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Flat Landing Brook Formation: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. A symmetrical repetition of the footwall-iron formation-hanging wall stratigraphic sequence is observed in DDH-B357, with distinct felsic volcanic rock domains separated by the three iron formations. This is best explained by parasitic F2 folds on the west flank of the south-plunging Brunswick antiform, similar to the fold closures known to host massive sulfide accumulations in the Brunswick No. 6 and No. 12 mines. Iron formation geochemistry and felsic volcanic rock chemostratigraphy from drill core sampling can provide an effective mineral exploration tool for the structurally complex rocks of the Bathurst Mining Camp. Sommaire - Le forage au diamant DDH-B357, situé à 1.5 km au nord du gisement de Sulfures Massifs à Encaissant Volcanique et Sédimentaire (SMEVS) de Zn-Pb-Cu-Ag Brunswick No. 6 recoupe trois horizons exhalatifs au sein des roches volcaniques felsiques diversement altérées des formations de Nepisiguit Falls et de Flat Landing Brook. Ces trois intervalles de formation de fer, impossibles à distinguer pétrographiquement les uns des autres, représentent vraisemblablement des unités sédimentaires hydrothermales cogénétiques sur la base de leur signature géochimique commune: Fe2O3T = 42.9 ± 10.5 % poids, MnO = 5.4 ± 3.1 % poids, des teneurs élevées en métaux usuels (Zn+Pb = 1999 ± 1091 ppm), un fort enrichissement en composantes exhalatives additionnelles (CaO = 5.3 ± 3.9 % poids; P2O5 = 1.43 ± 1.00 % poids), une signature oxydée (Fe/ Mn = 10 ± 6), ainsi qu’une signature d’éléments immobiles communs (Zr/TiO2 = 0.025 ± 0.007) indicative d’une source pélagique. Les roches volcaniques encaissantes calco-alcalines à transitionnelles peuvent êtres reconnues par leur rapport Zr/TiO2, et à un moindre degré par leur rapport Th/Nb: Formation de Nepisiguit Falls: Zr/TiO2 = 0.053 ± 0.004, Th/Nb = 1.08 ± 0.37; Formation de Flat Landing Brook: Zr/TiO2 = 0.107 ± 0.043, Th/Nb = 0.86 ± 0.17. Une répétition symétrique de la séquence stratigraphique Mur-Formation de Fer-Toit a été observée dans le forage DDH-B357, avec des domaines distincts constitués de roches volcaniques felsiques séparés par les trois formations de fer. La meilleure explication est que le flanc ouest de l’anticlinal Brunswick à plongée sud est affecté par des plis parasites F2, similaires aux zones de charnière contenant les sulfures massifs des mines Brunswick No. 6 et No. 12. La géochimie des formations de fer et la chimiostratigraphie des roches volcaniques felsiques en forage peuvent fournir un outil d’exploration minérale efficace dans les roches structuralement complexes du Camp Minier de Bathurst."

Jan 1, 2006

By H. S. Wilson

"The property owned by the Lamaque Mining Company comprises a group of forty-four claims and fractions occupying an area of about 2,458 acres, in west-central Bourlamaque township, Abitibi county, Quebec. It is on ,the outskirts of the towns of Bourlamaque and Val d'Or, about 70 miles east of Noranda, near the eastern end of the belt of greenstones of Keewatin and Timiskaming age that extends eastward through Kirkland Lake into northwestern Quebec, terminating in Haig and Jurie townships 40 miles to the east.The claims on which the orebodies occur were first staked in 1923; No. 3 vein was discovered the following year. The original discovery was made by R. Clark in 1923. This was a small quartz vein containing a pocket of coarse gold on the north side of a hill near the northwestern corner of block 3. It is said that all the gold was removed in one shot in blasting into the vein; elsewhere it was barren. A picket line was then run west along the strike of the vein, which occupied a narrow shear zone, and about 2,000 feet west, in prospecting on either side of the picket line, a large boulder of quartz and tourmaline containing visible gold was found. This led to more intensive prospecting by trenching in the vicinity with the result that the No. 3, or 'float' vein, about 250 feet north of the boulder, was found. Due to low ground this vein was exposed in only one trench. The only other important vein found on the surface was the No. 1, or H, vein, which was exposed in several places by stripping and trenching, but it did not carry appreciable amounts of gold."

Jan 1, 1954

By D. J. W. Piper, T. Hundert, G. Pe-Piper

"Abstract - Potentially commercial deposits of kaolin are found in the fluvial Lower Cretaceous Chaswood Formation, the sedimentologically proximal equivalent of deltaic sediments of the offshore Scotian basin. The geological setting of the kaolin deposits has been interpreted from high-resolution seismic-reflection profiles and boreholes, and mineralogical studies on one reference borehole. The kaolin is a product of early diagenesis involving meteoric water below the water table. The distribution of kaolin is controlled by the presence of intraformational unconformities that were sites of ground water recharge, and are marked by the development of oxisols above the water table. Such diagenesis was facilitated by interbedded, loosely consolidated, permeable sandstone. The highest-grade kaolin deposits are found in areas close to river belts, where overbank muds were not sufficiently drained to develop paleosols, but where later uplift created intraformational unconformities. In the sandstone, meteoric water flow altered feldspars to kaolin, thus yielding commercial silica sand deposits. It also altered ilmenite to rutile, which is concentrated as secondary placers in modern rivers that have eroded the Chaswood Formation and tills derived therefrom. Sommaire - Des dépôts de kaolin potentiellement économiques ont été notés dans la Formation de Chaswood d'’âge Crétacé Inférieur, laquelle constitue un équivalent latéral en milieu fluviatile aux sédiments deltaïques du bassin de Scotian. Le contexte géologique de ces dépôts de kaolin a été interprété a partir de profils de seismique-réflection à haute résolution, de sondages, et d’études minéralogiques sur un sondage de référence. Ce kaolin est un produit diagénétique précoce formé par de l’eau météorique sous le niveau de la nappe phréatique. La distribution du kaolin est contrôlée par la présence de zones de recharge associées à des discordances intraformationelles marquées par le développement d’oxisols au-dessus du niveau de la nappe phréatique. La présence d’interlits de grès perméables faiblement consolidés a contribué à l’efficacité de ce processus diagénétique. Les dépôts de kaolin les plus riches se trouvent en périphérie des rivières, là ou les boues de la plaine d’inondation n’étaient pas suffisamment bien drainées pour permettre le développement de paléosols, mais où des mouvements verticaux subséquents ont crée des discordances intraformationelles. La circulation d’eau météorique dans les grès a entraîné l’altération des feldspaths en kaolin, générant ainsi des dépôts économiques de sable de silice. Elle a aussi causé l’altération de l’ilménite en rutile, que l’on trouve dans des placers secondaires situés dans des rivières contemporaines qui ont érodé la Formation de Chaswood et les tills qui en sont dérivés."

Jan 1, 2006

By L. R. Plitt

A new simple correlation has been developed to evaluate the performance of classifiers. The new correlation has been tested on existing data from 150 different hydro-cyclone classification tests. It is shown that this model provides a meaningful improved method of mathematically describing the classification process.

Jan 1, 1971

By Carlos Alberto Spier

The Águas Claras and Pico mines are two world-class, iron-ore mines hosted within Lower- Proterozoic banded iron-formations (locally known as itabirites) of the Minas Supergroup located in the Quadrilátero Ferrífero District, Minas Gerais, Brazil. The Águas Claras orebody consists of a 2,500 m long roughly tabular-shaped lens hosted within the dolomitic itabirite of the Cauê Formation. Dolomitic itabirite is the protore of the soft high-grade iron ore, which is the main ore type of the Águas Claras orebody, and represents more than 85% of the 284 Mt mined since 1973. Hematite is the main constituent of the iron ores. It occurs as martite, granular hematite and, locally, as specularite. Magnetite appears subordinately as relicts within martite and hematite crystals. Gangue minerals are very rare. These consist of dolomite, chlorite, talc and apatite and are especially common close to the contact with the protore. This virtual absence of gangue minerals is reflected in the chemistry of ores which are characterized by very high Fe contents (an average of 68.2% Fe). The Pico orebody is a continuous ~3,000 m long body of lenticular shape hosted within quartz itabirite, which is the protore of the soft high- and low-grade ores at the Pico mine. The soft high-grade ores, together with the low-grade ores, called iron-rich itabirite, are the main types of ores at the Pico mine, respectively representing approximately 51 % and 29 % of the reserves within the pit. The iron oxide mineralogy is the same as that of the Águas Claras mine, but in different proportions. Gangue minerals are very rare in the high-grade ores, but are slightly more common in the iron-rich itabirite. Quartz is the dominant gangue mineral, and is found with minor quantities of chlorite. The chemistry of the high-grade ores is characterized by high Fe contents (an average of 67.0 %) and low P, Al2O3, and SiO2 which are concentrated in the fines. Iron rich itabirites average 58.6% Fe and 13.5% SiO2.

May 1, 2003

By S. R. McCutcheon, D. R. Lentz, W. S. Downey

"Abstract - The Little Falls member of the Nepisiguit Falls Formation is situated in the northern part of the Brunswick Belt of the Bathurst Mining Camp and has been interpreted as the distal equivalent of proximal tuffaceous rocks that host the stratiform Brunswick No. 12 and No. 6 Pb-Zn massive sulfide deposits. It comprises fine-grained, greenish-gray tuffaceous sandstone in the lower part, and coarse-grained, crystal-rich tuffaceous sandstone in the upper part. Petrographic evidence suggests that these rocks have a turbiditic origin. The Little Falls member is underlain by the Vallée Lourdes member, mainly composed of relatively shallow-water calcareous rocks, and is conformably overlain by Mn-rich sedimentary rocks, mainly red argillites that host the Tetagouche Falls Mn-(Fe) deposit. All these rocks are considered to belong to the Nepisiguit Falls Formation, part of the Ordovician Tetagouche Group. Whole-rock geochemical data from the fine-grained tuffaceous sandstone and coarse-grained tuffaceous sandstone indicate that the two units of the Little Falls member are distinct. Zr and TiO2 contents, and total rare earth element (REE) values are higher in the coarse-grained unit (average Zr/TiO2 = 0.040, average SREE = 247 ppm, n = 6) than in the fine-grained unit (average Zr/TiO2 = 0.048, average SREE = 158 ppm, n = 17), which can be attributed to the variation in crystal content between the two units. Both units are HREE-enriched and have elevated La/Yb relative to the typical Nepisiguit Falls Formation. Overall, the geochemical data combined with evidence from the bounding units suggest that the Little Falls member was deposited in relatively shallow water, possibly in a near-arc environment. The relationship of volcanic facies within the Nepisiguit Falls Formation and the geochemistry of these facies indicate strongly that fine grained, reworked tuffaceous rocks, regardless of whether they are the distal equivalents of proximal tuffaceous rocks, are not associated with the major ore-bearing horizons of the Bathurst Mining Camp. Sommaire - Le Membre de Little Falls de la Formation de Nepisiguit Falls se retrouve dans la partie nord de la Ceinture Brunswick du Camp Minier de Bathurst ou elle a été interprétée comme l’équivalent distal des roches tuffacées proximales hôtes des gisements de sulfures massifs de Pb-Zn stratiformes Brunswick No.12 et No.6. Il consiste en grès tuffacé à grains fins gris verdâtre dans sa partie inférieure et en grès tuffacé à grains grossiers riche en cristaux dans sa partie supérieure. Les données pétrographiques suggèrent que ces roches ont été déposées par des courants de turbidité. Le Membre de Little Falls repose sur le Membre de Vallée Lourdes, lequel consiste principalement en roches calcareuses déposées en eau relativement peu profonde; il est de plus recouvert en concordance par des roches sédimentaires manganifères, lesquelles consistent principalement en argilites rouges hôtes du gisement de Mn-(Fe) de Tetagouche Falls. Toutes ces roches appartiennent à la Formation de Nepisiguit Falls, laquelle fait partie du Groupe de Tetagouche, d’âge Ordovicien. Les données lithogéochimiques des grès tuffacés à grains fins et à grains grossiers indiquent que ces deux unités du Membre de Little Falls sont distinctes. Les teneurs en Zr et en TiO2, ainsi que la teneur totale en Éléments des Terres Rares (ÉTR) sont plus élevées dans l’unité à grains grossiers (Zr/TiO2 moyen = 0.040, SREE moyen = 247 ppm, n = 6) que dans l’unité à grains fins (Zr/TiO2 moyen = 0.048, SREE moyen = 158 ppm, n = 17), ce qui pourrait s’expliquer par la variation de la quantité de cristaux dans chacune de ces deux unités. Chacune de ces deux unités présente un enrichissement en ÉTRL ainsi qu’un rapport La/Yb relativement plus grand que ce qui est typiquement observé dans la Formation de Nepisiguit Falls. Les données géochimiques considérées conjointement à l’information provenant des unités adjacentes suggèrent que le Me"

Jan 1, 2006

By E. Fritz

This paper reviews the history, developments and 10 milestones of the oxygen steelmaking processes, with a special focus on conventional autothermic converters, high-speed converters with a blowing rate up to 5 m3n/t min and allothermic converters with coal addition, post combustion and the possibility to increase the scrap rate up to 50%. Related operating results are introduced. A new process route, which is based on hot metal and chromium ore, is outlined. The cost advantage for the production of 304 stainless steel grade is higher than 100 USS/t. The synthesis of EAF and oxygen converter steelmaking, a comparison of decarburization rates, refining combustion burners for optimized oxygen-management in EAF and an example for a large advanced EAF are outlined. Possibilities of flexible steelmaking and the growth and outlook of worldwide oxygen steelmaking are described.

Jan 1, 2004

By H. Salomon-de-Friedberg

The amount of pyrite in copper concentrates fed to the CESL Process can vary appreciably. The fraction of pyrite that oxidizes influences both capital and operating costs and is therefore an important variable. The present paper explores operating conditions that influence the extent of pyrite oxidation and the probable overall reaction chemistry under CESL conditions.

Jan 1, 2014

By J. E. Moran

A groupd of French capitalists, La Compagnie Française des Mines d'Or du Canada, has undertaken the considerable task of developing Otter creek, in the Atlin district, B.C., by hydraulic mining methods. It has long been known that the gravels of this stream carry sufficiently high values in gold to make it attractive as a mining venture, but it was impossible to ignore the existence of formidable natural obstacles to hydraulicing them, and these needed to be taken into serious account before embarking upon any costly programme of development. The tide to the Otter Creek leases was originally held by Mr. H. Maluin, a French engineer well known throughout the north, to whom was to fall the task of financing whatever programme might be decided upon. It was he, too, who would have to assume the responsibility of finally passing judgment upon the practicability of the various devises for overcoming the adverse natural conditions. With an infinite attention to detail, which I believe to be a characteristic of the French people generally, he studied his problem and was finally able to submit to his financial backers a programme which left the very minimum possible to the hazard of accident or chance. Dr. Mandy, on his visit to Otter creek this season, expressed the opinion that our method of opening this difficult creek presented certain features which might be successfully applied in placer operations elsewhere in British Columbia, and it is largely for this reason that the present paper has been prepared. I shall set forth, as well as I can, the practices which have enabled us to overcome rather easily some of the obstacles which nature had unkindly placed in the path which we must take. The natural flow of water in Otter creek is far too little to deal success-fully with the rather excessive amount of glacial drift overburden which lies directly over the gold-bearing gravels. For this natural defect, the only remedy was to procure more water. This we have clone through a system of flumes and ditches, totalling between ten and eleven miles in length, which bring to the mine a supply of water adequate for our needs.

Jan 1, 1932

By Derek Perkins

"Brenda Mines Ltd. operates an open pit copper and molybdenum mine located in south central British Columbia. The main economic mineralization is chalcopyrite and molybdenite. Pyrite, galena and sphalerite are also present in varying quantities. The mineralization is present in small veins and fractures in a porphyritic quartz diorite host rock.The mill processes approximately 30,000 tonnes of ore daily. The ore is crushed in three stages and then ground in conventional rod mill - ball mill circuits with cyclone classification. The cyclone overflow is fed to the bulk flotation circuit as a pulp with a density of 50% solids. The particle size distribution is approximately 35% plus 65 mesh. Bulk rougher and cleaning flotation produce a concentrate grading approximately 20% copper and 4% molybdenum. This concentrate is fed to the separation circuit, where the copper is depressed with sodium hydrosulphide and the molybdenum is floated. These products are further ground and then upgraded by column flotation. The molybdenum concentrate is pumped to the leach plant to reduce concentration of lead and copper. It is then washed, filtered, dried and packed for shipment to Europe. The copper concentrate is filtered, dried and subsequently shipped to Japan.Prior to November 1977, the mill flotation control was carried out by the assay laboratory using a Philips PW 1540 sequential x-ray spectrograph. The assay set consisted of twelve samples, analysed on a two hourly basis for copper, molybdenum, lead, iron and silica.In order to provide elemental composition information on a much shorter sampling interval and to produce speedier control analysis for automating process control, an Applied Research Laboratories PCXQ on stream analyser was purchased. The installation of this analyser, reduced the turnaround time of the control analyses from (2) hours to (20) minutes. At Brenda, the following assays are used in the mill control strategies."

Jan 1, 1989

By J. Boldy

This paper is an attempt to place Canadian Precambrian volcanogenic deposits in perspective, by examining and compiling data regarding certain neglected fundamentals of size, grade, value, frequency distribution and spatial density. The discovery roles played by various exploration methods are compared and contrasted, and. using empirical methods, the probabilities of discovery are discussed, combined with the use of an effective 'cost-per-target' program. From these basic observations, realistic exploration judgments may be made. Using similar methodology, this format may be applied to other types of deposits. Precambrian volcanogenic deposits occur in a natural geometric progression in size. They number 110, of which 70% are pre-producers, producers or past-producers. These deposits are bonanzas and generally have a 'net pre-smelter' value of between $43 and $62 per ton. The statistically typical deposit is that which occupies the modal position, has 400,000 tons of ore, a value of $20 million and occurs with a frequency of 40%. A median deposit has 1.4 million tons of ore, a value of $70 million and occurs with a frequency of 15%. An upper-decile deposit ha s 13.3 million tons of ore. a value of $750 million and occurs with a frequency of 6.5%. The major, mid-upper-decile deposits have a minimum of 50 million tons of ore, a value of $3 billion and occur with a frequency of 4%. Five major volcanogenic deposits occur in the Precambrian and account for 54% of production. This contrasts with 55 deposits (all below the median) which account for 3.9% of production.

Jan 1, 1977

By A. W. Jolliffe

AEROPROSPECTING may be defined as the application of the air view to the search for mineral deposits. The term is suggested as a preferable alternative to either aerial prospecting (which may be confused with areal prospecting) or air prospecting. The air view may be obtained by visual observation from an aircraft or by examination of air photographs; each has its particular advantages and disadvantages. Aeroprospecting should be regarded only as an aid to, and not as a substitute for, accepted prospecting methods ( l ). The Precambrian region north of Great Slave lake consists of two well defined physiographic units, a feature first noted by J. T. Wilson (2). The boundary between these lies close to the north shore of the east arm of the lake and extends northwesterly near Spencer, Beniah, Carp, and Ghost lakes (Figure 1). South and west of this line, exposed bed-rock makes up the greater part of the land area; eskers are very rare, and overburden is largely limited to rock-walled valleys and depressions. North and east of the line, outcrops are rare or absent, eskers are abundant, and most of the surface consists of drumlin-like drift hills, elongated parallel to the direction of ice movement (Figure 2). Where this boundary passes through the area shown in Figure 1, it lies near the 1,200-foot contour and may mark the maximum extent of the lake or sea arm present in this vicinity toward the end of the Pleistocene period. For convenience, the first area may be called the 'bed-rock belt' and the other the 'drift belt'.

Jan 1, 1945

By W. A. Jones

THE estimation of the average value of gold ore involves many considerations, among them the correct sampling of the deposit, the dilution by waste, and the loss of high-grade fines. It is a common experience that, after all these factors have been evaluated, adjustment of the assays is necessary before satisfactory agreement between the calculated mine grade and the mill heads is obtained. In fact, at many mines the latter correction overshadows all others in the preparation of routine estimates. For this reason it is proposed to deal only with the mathematical treatment of mine assays and the problem of bringing estimates into conformity with the corrected mill heads. Mine assays differ from physical measurements because the range of values is very great and these are not symmetrically distributed above and below the average, there being fewer high than low results. There is no widely accepted mathematical procedure for determining the average of series of measurements which exhibit these characteristics. Customary practice consists in empirically reducing high assays until a satisfactory agreement with mill heads is reached. It was thought that more confidence could be placed in grade estimates if a logical basis for calculations could be devised .. In an attempt to find a fundamentally sound procedure, amenable to practical application, many series of assays comprising over 235,000 channel samples (1) were studied at Hollinger Consolidated Gold Mines, Limited. Such an investigation could only be made where records covering many years of operation are available and where tabulating and calculating machines are in use. The results are recorded in the hope that the relationships noted for the large groups of assays used are of fundamental character and that the data will be useful to others dealing with the problem of grade estimation.

Jan 1, 1943

By Tom Dettweiler

Who We Are A global pioneer in discovery, development and recovery of deep-ocean assets Shipwrecks Deep-sea Minerals Company Overview Founded 1994 HQ ?Tampa, Florida USA Employees 45 Tampa + 150 Abroad Publicly Traded: NASDAQ:OMEX Requires Specific Financial Controls and Reporting

May 1, 2013

By Yves Prévost, Guy St-Amant, Guillaume Dion

In 2010, the foreseen increase of copper grade in feed concentrate at the Horne Smelter was a significant challenge to maintain a steady copper flow throughout the process. The Horne Smelter process includes a Noranda Reactor, a Noranda Converter, pyro refining vessels and anode furnaces. Of the many challenges involved, improving the single casting wheel performance was one of the key topics. Its reliability had to be improved to meet the new production objectives, as anode copper production was to increase from 170 000 to 225 000 tonnes/year. A multidisciplinary team was dedicated to improve the casting wheel availability. The improvement project allowed pinpointing failure modes and reviewing operational and maintenance practices. The common understanding developed by the team allowed improving small components with a high gain-to-effort ratio. The project allowed reaching operational targets without any significant investment. INTRODUCTION In operation since 1927, the Horne Smelter, located in Rouyn-Noranda, in Quebec, has undergone several technological changes since its original construction. Built to smelt the Horne mine concentrates, the smelter also accepted some local custom feeds from the first years of operation. When the Horne mines stopped production in 1976, the plant became a 100% custom smelter. With the development of the Noranda Reactor (1973) and Noranda Converter (1997), the Horne smelter increased its productivity and improved its environmental performance. Continuous improvement of the Horne process allowed maintaining a high level of flexibility in the operation of the smelter, while improving its overall capacity.

Jan 1, 2019