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By B. A. Zaharov, J. M. Shneerson, L. V. Chugaev, M. T. Zhunusov, A. M. Markelov, S. V. Drozdov

The main direction of research was the application of autoclave technology for the flotation concentrates or biooxidation feedstocks. The industry modernization also expects the possibility of increasing the yield of the flotation concentrate, to allow an increase in gold extraction in flotation circuit. This paper provides brief description of results obtained for concentrates with the yield of 4 and 8%, as well as corresponding biooxidation feedstocks. Technological efficiency of autoclave oxidation is shown for both concentrates and biooxidation feedstocks. The process has been evaluated on a laboratory and a continuous pilot plant scale. Gold extractions from POX discharge are ranging from 94-97% for each product, with only 5-7 kg/t cyanide consumed.

Jan 1, 2014

By G. Wren

As base metal sulphide resources become increasingly challenging to process, producers seek alternative options to treat concentrates. This study considers the mineral, elemental, and leaching character of a West Australian nickel sulphide deposit (Cosmos Nickel Project). After a brief review of the published work bench top leach tests were conducted to examine the factors which impact the kinetics of nickel sulphide leaching such as particle size, temperature, acid strength and type, concentration of copper sulphate and sodium chloride, and oxygen partial pressure. The effect of sodium chloride was considered due to the common occurrence of hyper saline water at West Australian nickel sulphide mine sites. Ultrafine grinding to an 80% passing size of 10 µm resulted in high nickel leaching efficiency. Moreover, higher concentrations of acid, copper(II) and sodium chloride also gave higher nickel and cobalt leaching efficiencies but arsenic precipitated as FeAsO4. Under the most suitable conditions the extractions of nickel, cobalt and arsenic at 90oC after 6 hours were >95%, 90% and <5%, respectively. The comparison with results from high pressure operations indicates the possibility of using a hydrometallurgical flowsheet based on fine grinding and atmospheric pressure leaching and warrants further investigations.

Jan 1, 2014

By Robert Macdonald, William Coombe, John F. Lewry

Gold occurrences have been known in the La Ronge Domain for many year . Mineable reserves have more recently been outlined and there is every prospect of a major gold camp being established in the domain within this decade. The La Ronge Domain lies in the Lower Proterozoic 'Trans-Hudson Orogen' and is part of a collage of Early Proterozoic crust comprising volcanoplutonic arcs, batholiths, associated volcaniclastics and volcanogenic sediments lying between the Superior Craton to the outheast and the reworked Archean basement/Aphebian cover terrain to the northwest. The domain has several lithostructural subdivisions, the most important of whjch , from a gold exploration point of view, is the Central Metavolcanic Belt. This belt is composed dominantly of a range of metavolcanic rocks and gabbroic to granitic intrusives, which geochemically resemble younger subduction-generated 'primitive' arcs developed on oceanic crust. U-Pb zircon geochronology indicates that the arc volcarusm and pre- to late-kjnematic plutonism occurred about 1890 Ma to 1850 Ma ago. The belt has an attained grade of upper greenschist to amphibolite facies and is relatively undeformed , though high strain zones occur locally. Most gold occurrences in the La Ronge Domain have been found in the Star-Waddy Lakes area of the Central Metavolcanic Belt, and in the Sulprude-MacKay Lakes area to the south which is interpreted as a tectonically dismembered part of the main belt. Both tratiformand vein-type gold occurrences are present in the domain; vein-type predominate and form nearly 90 per cent of the occurrences. The stratiform-type occurrences show a regional lithological a sociation with iron-rich sediments within proximal felsic volcanjc sequences. Some vein-type occurrences appear related to brittle fracturing associated with intrusive emplacement (the magmatic-hydrothermal "syn:' and "subvolcanic" veins) and faulting. However, most of the vein-type occurrences exhibit a spatial association with regionalscale ductile shear and other high strain zones, and were probably formed by metamorphichydrothermal processes.

Jan 1, 1986

By Veronique Falmagne

"In 1987 the only knowledge available of the Ansil orebody was that it was high grade, deep and relatively small . High stresses were also anticipated because there had been rockbursts during shaft sinking and destress blasting had been necessary (Fig. 1). From the design, through the development and now in the mining stage, rock mechanics and microseismic monitoring have been used to maximize recovery and safety and minimize dilution. Examples are given of the use of a microseismic monitoring system in the early stages o f mining. This paper also presents a review of the mine&apos;s in situ stress measurement campaign, cable bolting practice and backfill procedure.The Design PhaseAfter the initial mapping and classification work, preIiminary numerical modelling was performed using assumed stresses of ov = oH and oH = 3ov• The empirical Mathew&apos;s analysis was then used to optimize stope dimensions based on geomechanics data available at the time (Bawden et 01., 1988; Falmagne, 1987; Potvin et 01., 1988). Because of high stresses predicted by numerical modelling and a brittle, strong and relatively unfractured host rock which was believed to be rockburst prone, it was decided to mine without temporary or permanent pillars. However, in order to satisfy production rates, the orebody had to be broken up into two horiwns separated by a triangular pillar (Fig. 2). The final mining sequence is shown in Figure 3.The Development PhaseAt this point, based on work accomplished to date, including mapping and observations from drifting and modelling, the following problems were identified: (1) flat backs in the hangingwall andesite were thought to be highly stressed; (2) flat backs in weak massive sulphide ore would also be subjected to high stress and be difficult to support; (3) the felsic dyke was noted as a "" stress raiser"" , because activity increased as drifts approached it; and (4) chlorite coating of joints in the hangingwall was thought to be an important factor in reducing their stability."

Jan 1, 1991

By R. W. Culley

"In many areas of Saskatchewan, known gravel deposits have been depleted or are diminishing rapidly; in other areas, particularly in the north, demands for all-weather highways and access roads are far exceeding the supply of gravel sources with which to surface them. These two problems have made conventional methods of air-photo and ground surveys insufficient for gravel location. In the first case, hauling costs on construction now warrant searching for buried deposits and for smaller, less obvious surficial deposits that may be closer to the project. In the second case, search and access conditions are so difficult and costly that the ratio of successes to failures must be kept very high. The Department of Highways has long been aware of the oncoming scarcity of quality gravel deposits and is continually investigating ways of forestalling it. One of these ways is the use of airborne geophysical methods that permit rapid coverage of large areas and that sense and discriminate between earth properties to a significant depth below ground surface. In 1967, the Department began an investigation of an airborne conductivity survey method called INPUT*, or ""Induced Pulse Transient'', leading to a trial in 1968 and data analysis in 1969. The results of this trial initiated• modifications to the technique to improve its sensitivity for mapping shallow deposits. Part way through this modification in 1970, a decision was made to change to an airborne resistivity survey method called EPHASE*. Trials with this technique were conducted and analysed in 1971. This paper is an explanation of the E-PHASE system and a summary of the results from one of three areas mapped in 1971."

Jan 1, 1973

By Dave Thomas

?Uranium is a common trace metal at the earth?s surface, but these are amazing super-high grade (up to 25%) pods, veins and disseminated uraninite (UO2) near unconformities between Proterozoic siliciclastic red beds and metamorphic basement with graphitic metapelite and radiogenic granite. ?Pitchblende fills extensional features in reactivated fault zones and replaces matrix in sandstone ?One mining district in Canada ?the Athabasca Basin ->30 deposits /prospects -most in eastern ¼of basin -produces 1/3 of world?s U -employs northerners -VERY high tech -VERY high safety standards Unconformity-associated uranium depositsUnconformity-deposits

May 1, 2006

By Wayne N. McKee, Scott A. Lewis

"Introduction to the Syncrude OperationSyncrude Canada Ltd., located 42 km north of the city of Fort McMurray, Alberta, (Fig. I) is an integrated operation that has produced synthetic crude oil from the Athabasca oil sand deposit since 1978.The operation, consisting of a surface mine, an extraction plant, a bitumen upgrader, and a utilities plant, is currently capable of producing over 60 million barrels of crude oil per year. Production is expected to increase to 70 million barrels of crude oil per year over the next five-year period with no major changes to equipment or process planned.The Syncrude surface mine, producing a total of 675 000 tonnes of ore and waste per day, rates as one of the largest mines in the world. A strip mining method is utilized, with two or three operating benches necessary to excavate a total depth varying between 60 m and 70 m. The 20 m to 30 m of overburden is removed by electric and hydraulic shovels and 200-ton haul trucks, and dumped in the mined-out pit for final storage. The overburden operation creates a flat bench near the top of the ore zone on which the four 60 m3 draglines operate. The draglines excavate interbanded ore and waste in the highwall, with ore placed on the operating bench in windrows, and waste returned to the mined-out pit. The windrowed ore is reclaimed by four bucketwheel reclaimers, and discharged onto a conveyor system for transfer to the extraction plant."

Jan 1, 1993

By Jeanie Wills, Theresa Nyabeze, Samantha Espley, Donna Beneteau

This presentation reports survey findings that aim to modernize the definition and understanding of the term 'mining.' The survey, conducted via LinkedIn in Winter 2024, garnered responses from a diverse group of individuals, including current or former employees of mining or exploration companies, mining consulting firms, service providers, supplier firms, as well as students and retirees with industry experience. The data, ethically approved by the University of Saskatchewan, offers valuable insights into satisfaction levels within the mining sector and suggests an expansion of the identifying characteristics of definitions of mining. This marks the third CIM gaining insights paper by Beneteau, Espley, and Nyabeze, following previous works on 'Career Satisfaction for Women in Mining' (2010) and 'Mentorship Initiatives in the Canadian Mining Industry' (2018*)."

Oct 1, 2024

By K. C. Lahiri, H. P. Das, G. G. Sarkar

"The petrographic components of any particular rank of coal often show some distinct physical and chemical characteristics. Therefore, their pro-portionate distribution in a coal greatly influences the technological behaviour of the coal.In any size or gravity separation of a coal, the petrographic constituents become segregated to different degrees in some preferred size or specific gravity range. Therefore, a knowledge of the petrographic nature of the washed and/or screened fractions is often considered essential in selecting the most efficient method for coal preparation and in exploring the proper evenues for its utilization.A graphical method is described in this paper to indicate the mineral-matter content and the petrographic components of the washed fractions of a coal at different ash levels of separation in the form of a new washability diagram. This diagram can be conveniently used to assess or predict the petrographic composition of clean coal or sinks corresponding to any desired ash level in the cleans. With the help of this diagram, it is also possible to locate the yield level of cleans at which maximum enrichment of vitrinites and exinites occurs with the least amount of mineral-matter content."

Jan 1, 1971

By C. J. Newman, K. Molnar, A. G. Storey, G. Macfarlane

"The Kidd Creek copper smelter started operation in June 1981 using the Mitsubishi Continuous Smelting Process. A steady increase in plant production rates has been demonstrated, and the annual tonnage of concentrate smelted is now double the original design rate. This paper summarizes recent modifications made to increase concentrate feed rates, increase on-line time, reduce copper losses and control the impurity level in anode copper. It includes improvements made to furnace design, improvements to reduce downtime f or boiler cleaning, and improvements made to the acid plant to allow handling of increased gas flowrates and higher gas strengths while maintaining low acid plant emission rates. IntroductionThe Kidd Creek Division of Fal conbridge Limited operates a base-metal mining and metallurgical complex, located in Timmins, Ontario, which includes an underground mine, a 13 500 tonne/day concentrator, a 130000 tonne/year zinc plant and a copper smelter and refinery, The copper smelter and refinery were commissioned in 1981, with an installed capacity of 59 000 tonnes/ year of cathode. The smelter, utilizing the continuous smelting technology of the Mitsubishi Process, has subsequently been expanded in production capacity, and in 1991 produced 113 500 tonnes of blister copper The capacity of the refinery, which uses Onahama No. 3 tankhouse technology, has been increased to 96 000 tonnes/year of cathode. The capacity increase at the smelter has been realized through the input of additional oxygen to both the smelting and converting furnaces, without increasing the process off-gas flowrate through the associated waste heat boilers.In this paper, a brief review of smelter operation and modifications in the period 1982 to 1987 is presented, together with a more detailed discussion of operation during 1988 to 1991, and a discussion of future planned improvements."

Jan 1, 1992

By P. J. Noakes

Remote and isolated, located in a frigid, hostile environment, the Black Angel mine in Greenland had to create a warm social environment which would help attract and retain a stable work force of miners and support staff. The high cost of personnel turnover plagues many mines and, when the mine is inside the Arctic Circle, accessible by helicopters which are highly vulnerable to unpredictable weather conditions during the long, dark winters, the potential costs of personnel turnover become critical factors in the success or failure of the mining venture. Manpower planning should start from the date the engineers begin the technical design of the new mine. The plan should include provisions not only to ensure an adequate, skilled work force, but also to ensure a stable work force of people who are happy enough in the mining environment to want to remain, take their vacation and return to work at the mine. The skilled work force was assured with training courses of four months, designed to produce highly specialized underground workers from unskilled Danes and Greenlanders supported by trained Swedish and other Scandinavian miners. The stable social unit was assured by plans the primary attribute of which had to be flexibility. The accommodation changed from shared accommodation with communal washroom facilities to single accommodation with private washroom facilities. A recreational director was hired to help the workers make use of elaborate recreational facilities. A closed-circuit TV and radio system was installed to operate as a private broadcasting system using taped programs originally broadcast on European TV networks or developed by the mine personnel themselves. The liquor rules were changed and the mine manager became a licensed innkeeper responsible for the orderly operation of the Black Angel Bar in accordance with the Danish laws governing the services of a public bar. The result is a relatively stable work force. Some 35% of the people have more than two years&apos; service with the company, Greenex A/S, and some 62% complete 10 months of service.

Jan 1, 1978

By Ralph W. Edie

"IntroductionTHE GOLDFIELDS AREA in northern Saskatchewan has be-come important in recent years because of numerous discoveries of pitchblende. The area is underlain by rocks of Precambrian age and, because of metamorphism and hydrothermal alteration, the geology in the vicinity of the pitchblende deposits is exceedingly complex and presents a challenge to all geologists •working in the district. This paper is a contribution to the geological literature of the area and presents a description of rock types, supplemented with petrographic, chemical, and spectrochemical data.Field work in connection with this paper was carried out during the summers of 1948, 1949, and 1950 while the writer was employed as assistant geologist for the Crown Corporation, Eldorado Mining and Refining ( 1944), Limited, Gold-fields area. Laboratory work was undertaken at the Massachusetts Institute of Technology during the winter months of 1949-50 and 1950-51 and extended through the summer of 1951.With the exception of SiO2and FeO, all of the new analyses ( 1) presented were carried out by quantitative spectrographic techniques under the supervision of Dr. L. H. Ahrens at M.I.T. Many of the techniques have only recently been developed at that Institute and detailed laboratory procedures have not yet been published."

Jan 1, 1952

By J. Peck, F. Brackebusch, M. Scobie

"A number of alternative strategies exist to improve narrow orebody stope productivity and safety through mechanization. Particular attention is given to one of these: the development of an in-stope mining machine. This paper summarizes those characteristics of vein orebodies in Canadian mines which are considered to govern such mining machine design. It then reviews past and current attempts to develop hardrock mining machines which could potentially be applicable to narrow stope widths.IntroductionSerious interest is mounting to exploit new technology in the development of methods and machinery to stope narrow, hardrock, orebodies. The motives relate not only to the foreseen need to maintain or reduce production costs, but also to considerations of manpower availability, safety, ground control, ore recovery and dilution. This also follows the demonstrated success of technology application in larger metal orebody stoping, where machine development has been seen to lead to improved productivity as well as the future prospects of continuous mining systems and eventual automation, e.g. ITH blasthole drill development and bulk mining. This paper deals in particular with machine design for ore fragmentation in narrow, hardrock orebodies. It is considered that such machine design closely interacts with the over-all stoping method design and that both require consideration in parallel to ensure success in mechanization."

Jan 1, 1990

By D. G. Sediako

Chemical composition and the casting/rolling production routes determine the cost and properties of the wrought material. For example, the coarse-grained structure frequently associated with DC casting requires complex rolling schedules to refine the grain size. Hot forming (rolling/forging/extrusion) results in a strong crystallographic texture, which is responsible for the tension-compression strength asymmetry frequently exhibited by magnesium alloys. Understanding the influence of alloy composition on texture evolution during forming provides useful practical information to optimize industrial hot-forming technologies for magnesium alloys. In this study, a series of Mg-based alloys containing varying combinations of Al, Rare Earths, Zn, Ca, and Sr were subjected to identical casting and extrusion processes in order to isolate the effects of alloy composition on texture evolution. Textures were measured by neutron diffraction at the NRC Canadian Neutron Beam Centre. The ability of neutrons to penetrate deeply into materials allowed information to be retrieved from all regions of the bulk specimens without destructive and time-consuming sectioning operations, thereby providing true bulk texture data. {1010} , (0002), {1011}, and {1012} pole figures were generated for all of the as-processed alloys, from which Orientation Density Functions were obtained. The were then used to reconstruct the pole figures and to extract semi-quantitative texture data showing how the (0002) and {1010} planes align themselves with respect to the extrusion axis. It was found that varying the concentration of aluminum (3-4 wt%) and Rare Earths (2-3 wt%) in AE alloys had a weak effect on texture development. All of the alloys showed similar magnesium extrusion textures, in which the (0002) poles align themselves preferentially with the extrusion axis. The substitution of Sr for Rare Earths also did not have a significant impact on texture development. On the other hand, while the presence of small amounts of Zn and Rare Earths did not have a strong effect on texture development, alloys with higher concentrations of these alloying additions (in combination) showed an enhanced tendency for the {1010} poles to align themselves with the extrusion axis. The addition of Ca also enhanced the alignment of the {1010} poles with the extrusion axis. These textures can complicate further processing and introduce a significant anisotropy that could influence creep properties.

Jan 1, 2007

By K. Thuro, S. Schneider, H. Kasling, P. Ellecosta

"One of the most important methods for material testing is the characterization of the hardness, which is defined as the resistance of a material to the penetration of another one. The methods according to Brinell, Vickers, Rockwell and Knoop are today the most common and standardized tests for metal. As they are developed for predominantly ductile materials like steel, they can’t easily be applied to rocks which react much more brittle under indentation. But just as steel, rock is composed of different minerals and has a specific microstructure. Its mechanical parameters are connected with the particular grains, their cohesion and interlocking, just like steel.The abrasivity of rocks and the accompanied wear of drilling tools today are mainly determined by simple and fast laboratory tests such as the Cerchar abrasivity test or the rubber wheel test. Such laboratory tests are good tribological tests, but there are limits. The Cerchar abrasivity test for example has weaknesses in extreme cases, that mean soft or very hard rock types. This leads to an underestimation of abrasivity, e.g. in poorly lithified sandstones or very hard, fine grained and extremely abrasive rocks. As mentioned, hardness characterizes, depending on the type of deformation, predominantly plastic (metal) or elastic properties (rubber). Rocks are in the range between these two extremes. Since the rock drilling process can be seen as a kind of penetration process on macroscopic and microscopic scales, we picked up the idea to characterize the interaction of rock materials and TBM-disc-cutters with hardness tests. In addition, this supports for a better understanding of the wear process on disc cutters. We used the hardnessdisparity concept after Cardu & Giraudi (2012) because wear can be understood as the interaction between the wear part and the material which causes the wear (tribological system). Several rock-forming minerals and some fine to coarse-grained monomineralic and polymineralic rocks were tested. In contrast to Cardu & Giraudi, we used in the first step of investigations the method after Vickers with loads up to 294.2 N (HV 30), depending on the estimated hardness to get bigger indentations and therefore as well information about the cohesion and interlocking of the minerals/grains. We also tested several associated disc cutters. First results show that with higher loads (HV 5 - 30) and at least 15 indentations, we get a structural hardness in fine-grained rock samples, which allows a good characterization of the elasticity and brittleness. Nevertheless, for the coarse-grained rock samples we need up to 40 indentations for a good characterization. Using this method, a prediction of disc cutter wear is feasible taking into account the hardness of the disc cutter steel. In this paper, we would like to present this approved method in material sciences to derive an additional parameter for the characterization of rock abrasivity and wear."

Jan 1, 2015

By T. Alan O'Hara

"The decision to invest capital in developing a mine and constructing a mineral processing plant and services is usually made after a feasibility study shows &apos;that the estimated future cash flow from mine operations will yield an adequate return on the estimated capital expenditures.The actual return on investment may differ substantially from that estimated in the feasibility study, because of the probabilities of errors in estimating capital costs, ore reserves, operating costs, mineral revenue and operating productivity. This paper outlines the R.S.S. (root sum of squares) risk analysis procedure of computing the overall probability of the actual project D.C.F. (rate of discounted cash flow), differing from that estimated in the feasibility study.Variation in Project D.C.F.It is assumed that a feasibility study of the project has been completed which has defined the estimated values for all the project parameters, such as ore reserve tons and grade, capital cost, concentrate recovery, metal revenue, daily milling capacity and operating costs.The financial analysis of the mining project will have determined that the cumulative cash flow will yield an expected D.C.F. on the capital cost if all project parameters attain the estimated values. If, however, the actual value of any parameter varies from that estimated, the actual project D.C.F. will vary from the estimated D.C.F. Risk analysis methods attempt to determine the overall effect of probable variations in the estimated values of all project parameters on the D.C.F. of the mining project. This overall effect is expressed as a probability profile, which shows the likelihood of actual D.C.F. values greater or less than that estimated.Thus, a completed risk analysis of a mine project, with an expected D.C.F. of 15.51%, would display the characteristics shown in the preceding diagram."

Jan 1, 1982

By J. T. Sims, C. E. Karayannopoulos

Today&apos;s rare earth industry is undergoing significant and rapid evolutionary change toward greater reliability and diversity of supply, increased security of supply chains, and better price forecasting. Technology innovation is reducing rare earth production costs while decreasing the impact of producers on the environment. Advances in rare earth material science are reducing the need for relatively scarce heavy rare earths (HREEs) in high-performance neodymium-iron-boron (NdFeB) permanent rare earth magnets and opening the NdFeB magnetic market space for a broader range of downstream applications. Rare earth producers such as Molycorp are increasingly able to offer long-term supply agreements with forward price predictability, something that has not been the case for many years. All of these trends are helping to restore the confidence of customers and other stakeholders in the rare earth space. That increased confidence is likely to bolster global demand for rare earth materials and expand innovative utilization of these remarkable materials.

Jan 1, 2014

By Bordeaux Sciences Agro-INRA UMR 1065 SAVE, S. Piutti, E. Benizri, S. Lopez

Ultramafic soils display high concentrations of nickel (Ni) and a number of nutrient deficiencies (e.g. N, K, P). Ni-hyperaccumulator plants have evolved on such environments, developed specific metal homeostasis showing concentrations of Ni sometimes above 1% in their aerial biomass (Baker & Brooks 1989). Alyssum murale, a Ni-hyperaccumulator, is commonly found around the Mediterranean but can grow on non-ultramafic soils as well, with an altitudinal extension ranging from sea level to 2000 m.a.s.l. Rhizosphere bacterial communities associated with Ni-hyperaccumulator plants can differ from those of non-accumulating plants growing at the same site. Among edaphic factors that could influence the phylogenetic structure of the bacterial communities, altitude and metal-bioavailability and in particular nickel could be significant. However, most studies have focused on analyzing soils with techniques that provide little detail about the phylogenetic structure of these bacterial communities present in ultramafic soils. The objectives of this study were to understand the specific changes in the structure of A. murale rhizosphere bacterial community that occur across two gradients: 1°) elevation and 2°) Ni geochemistry, using pyrosequencing technique (454-pyrosequencing of 16S rRNA gene). It was found that the higher the soil chemically-available Ni contents, the higher the relative abundance of Proteobacteria and Actinobacteria. On the contrary, the abundance of TM7 decreased with increasing levels of available Ni. Moreover, Chloroflexi was present with 53 to 77% of relative abundance. These results demonstrate that soil chemically-available Ni drives the bacterial community diversity in the rhizosphere of Alyssum murale regardless the elevation gradient and other different soil physicochemical parameters. These results should now be confirmed in different ultramafic edaphic environments worldwide (e.g. ultramafic lateritic covers) and in the rhizosphere of different hyperaccumulator taxa.

Jan 1, 2016

By Elaine Ellingham, Francis T. Manns

"Abstract -The Orostar and Scadding were two small gold mines owned and operated by Orofino Resources Limited. Conventional statistical treatment indicates an identical arithmetic mean grade of 0.22 oz/T Au for both mineable reserves. Further, the deposits are both shown to have cut weighted average reserve grade of 0.21 oz/T. Orostar mined out at 0.206 oz/T and Scadding at0.156 oz/TAu . The combined exploration and development database contained 1394 fire assays, more than enough for statistical confidence in a normal distribution. Therefore this study was initiated to determine, if possible, why the mill head grades were lower than the averages and to experiment with several methods to determine whether a reliable statistical mill head grade estimation method would emerge. Despite the identical reserve grades, distinct differences in the grade distribution histograms are present. By studying the arithmetic and log-normal grade distribution s, with some attention to South African practices, this paper reports on those differences which may account for the considerable divergence in the mill head grades. Furthermore, this study casts considerable doubt on the industry standard method of cut weighted averages.The global mill head grades of the two deposits have been derived from the arithmetic average grades by graphic means. This precise method of mill head grade prediction, if applied to complex orebodies, could permit selective grade control and result in direct cost savings by allowing the operator to detect false value stopes, benches or levels and emphasize reliable regions of not only gold mines, but also uranium or base metal deposits."

Jan 1, 1992

By W. M. Goodwin

"IntroductionIN THE preceding paper we have learned about Canada's resources of metallurgical coal. There is an adequate amount in Nova Scotia, a very large reserve on the eastern flank of the Rocky mountains, and a strictly limited supply on the Pacific coast. Added to these is an unknown quantity of coking coal in the Peace River district, at present rather isolated but possibly capable of industrial development in the future.The chief use of metallurgical coal is to make iron and steel. For this, an adequate supply of iron ore is required. So we should now scan the Canadian supply of iron ore, the possibility of its increasing use at home, and the probable markets abroad.Trade in iron ore tends to be international, as is the case with many other raw materials. The present tendency with iron and steel, in contrast, is to keep its manufacture within national boundaries, and there is no evidence that this will change much in the years to come. We should keep these two points clearly in mind when considering the disposal of iron ore from Canadian mines. We should remember, also, that the modern blast furnace and steel plant has such a large output that a correspondingly large population, reasonably compact, is needed to consume its products.Large Ore Supply in East, Small in WestCanada has now four major iron ore fields, well situated to serve adequately the eastern half of the country. Wabana .and Labrador are well placed to serve overseas markets and plants on the eastern seaboard and eastern interior of the United States and Canada."

Jan 1, 1952