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By H. D. Goodfellow, R. A. Elliott

"This paper covers the evolution of large mills and autogenous grinding and compares grinding practice in the iron ore industry with that in the base metal industries. Comments on novel methods of grinding are presented for discussion. Recent developments in the field of classification are briefly reviewed. A systems analysis approach to grinding circuits is discussed. Finally, a point is made for establishing a group within the industry with the purpose of developing a comprehensive evaluation of grinding research and development."

Jan 1, 1971

By David J. T. Carson

"The metalliferous deposits of Vancouver Island have generally been assigned to the Mesozoic ""Coast Range Orogeny."" However, a metallogenic study by the writer has revealed that several important classes are early or middle Tertiary. Included are porphyry coppers, and gold-quartz, arsenic and copper-arsenic veins.The porphyry coppers and many gold-quartz veins are within and adjacent to Oligocene-Eocene quartz diorite intrusive complexes. Arsenic and copper-arsenic veins have a close spatial relationship to sills and laccoliths of Oligocene dacite porphyry which intrude the late Cretaceous Nanaimo Group.Other deposits of demonstrable Tertiary age include a molybdenum stockwork related to a relatively potassic Eocene plug and a few small copper-skarn occurrences. Some copper stockworks and a mercury deposit are probably also Tertiary.The copper deposits of previously recognized Tertiary age are those of the Sooke area that occur in Eocene basalts and Oligocene gabbros."

Jan 1, 1969

By U. Erb, L. Monaco

"Electrodeposited nanomaterials are increasingly implemented in advanced industrial applications in the aerospace, automotive, defence, electronic and energy sectors due to their outstanding physical, chemical and mechanical properties, including increased strength and wear resistance, and superb magnetic properties. As with the development of any class of new materials, the corrosion behaviour of these electrodeposits requires considerable attention. This presentation reviews major developments in the understanding of the corrosion behaviour of nanocrystalline metals, alloys and metal-matrix composites over the last 20 years, with emphasis on how their intrinsically high density of intercrystalline defects does not compromise their corrosion resistance as initially expected.INTRODUCTIONOver the past 20 years there have been considerable advances in the understanding of the corrosion behaviour of nanocrystalline metals, alloys and metal-matrix composites. In this paper, the corrosion properties of nanocrystalline nickel, cobalt, zinc, and copper and some of their alloys are reviewed with emphasis on how a reduction in grain size affects their corrosion behaviour in different environments.It is possible to synthesize nanocrystalline material with microstructural refinement down to the range of 1 to 100 nm using a large number of processing methods. There are five basic synthesis methods that can be used to classify the different techniques: vapor-phase processing, liquid-phase processing, solid-phase processing, chemical synthesis, and electrochemical synthesis. Depending on the synthesis method, different microstructures (equiaxed, textured), shapes, and forms (films, particles, bulk material) may be produced. In addition, other factors may be introduced (eg. residual porosity or amorphous phases), aside from microstructural refinement, which can contribute to the observed properties (Erb, 2010). In order to interpret and categorize the resulting microstructures, a dimensional structure modulation scheme was introduced by Siegel (1996) in which zero-dimensional nanomaterials refer to individual particles, clusters, etc. One-dimensionality results from a layered (less than 100 nm thick) structure. Two-dimensional nanomaterials are thin, layered structures containing grains (less than 100 nm) within each layer. Finally, three-dimensional nanomaterials are bulk structures with an average grain size less than 100 nm."

Jan 1, 2012

By T. W. Wlodek

"AbstractSatisfactory mine drilling operations depend on the good performance of the drilling machine, and of what may be called the drill set, i.e., the following four elements: bit, attachment, drill rod, and shank end. The field performances of these four elements in the drill set are analysed and their service lives are compared. The most .common causes of service failure are reviewed and possibilities of increasing service life are discussed.The laboratory methods now employed for the simulated service testing of tungsten carbide bits, conical push-on and threaded .types of attachments, drill rods, and shank ends are described, and some results are discussed. The objectives of the research programme now being carried out •on the above mentioned elements are outlined.A number of mines in British Columbia, northern Ontario, and northern Quebec have been visited, and, with the co-operation of the C.I.M. Branches in these areas, meetings with representatives of the mining and steel industries concerned have been held. In this paper, the mechanical-metallurgical problems most frequently encountered and discussed during these visits and meetings are described and .analysed.IntroductionSUCCESSFUL mine drill operations depend to a great extent on• the satisfactory field performance of the four elements which form the mining drill set, shown diagrammatically in Figure 1.These important elements are:1. -The bit, which may be one of the following types:(a) Detachable tungsten carbide bit( b) Inserted rod bit, so called chisel bit( c) Detachable steel bit( d) Solid rod bit"

Jan 1, 1952

By J. M. Ortiz, J. P. Bertini

"In mineral resource and ore reserve estimation, several sources of information are generally available, such as diamond drillholes, reversed-circulation drillholes, and blastholes, and originate from one or more sampling campaigns and are analyzed by one or more laboratories. In such a situation, the grade measurements may not have the same precision and one should distinguish between hard and imprecise data.This work aims at studying the impact of data imprecision in resource/reserve evaluation through two case studies on simulated deposits: a porphyry copper deposit conditioned to real exploration and production data, and a gold deposit simulated without any conditioning data. Several geostatistical techniques are used to estimate the grades of selective mining units from exploration samples, including kriging, cokriging, lognormal and indicator kriging. Two types of imprecision are examined— measurements with multiplicative errors and measurements defined as intervals. The results are compared to the simulated grades of the selective mining units from a statistical and economic viewpoint.The study concludes that imprecise measurements should never be discarded because they help to improve the estimates, and that simple methods such as kriging are as efficient as more sophisticated ones for resource/reserve assessment. Finally, a few indications on how to diagnose and model the data imprecision are given."

Jan 1, 2005

By Norman R. Paterson

"Under certain conditions useful gravity information of a reconnaissance nature can be obtained with-out measuring elevations by spirit level surveys on the ground. Gravity surveys can become part of a practical exploration program where high cost and slow progress previously hindered their utility. The advantages of the new elevation procedures are realized mainly in remote areas, in areas where ground transportation is slow and difficult and on surveys where the station spacing is large in comparison with the distance of the average optimum level shot. To utilize the advantages, transportation by helicopter or light plane is usually necessary. Methods of obtaining elevation control without leveling include: barometric altimeter survey; photogram-metric -APR spot determinations; methods involving the measurement of gravity gradients. The accuracies of these methods have been tested and compared with the normal accuracy of level surveys. It is felt that each method has its place in reconnaissance gravity work, particularly in the open areas of Northern Canada."

Jan 1, 1960

By G. E. Peacock

SIGMA MINES is situated in the township of Bourlamaque, Abitibi County, Quebec. It is a gold producer, and presently treats an average of 1,200 tons of ore per day, at a grade of approximately 0.18 oz. per ton recovered. The mill started operations in March, I937, at a rate of 300 tons per day. This was increased to 800 tons in I940, and to 1,000 tons by I943. The rate was cut back during the war years, but was brought back up to capacity by I948. The mill tonnage was in-creased to the present 1,200 tons per day in I960. The underground workings are serviced through No. 2 Shaft (Figure 1), which, with 24 operating levels, extends from surface to a depth of 3,317 feet. When depth exploration was decided upon, two possibilities were considered: (a) deepen the main shaft by1,000 feet; (b) put down a winze for the same distance.

Jan 1, 1962

By Unknown

With the present-day trend of rising labour costs and a lowering of production efficiency of workmen, it has become imperative that every effort be made to use manpower to the greatest advantage and to mechanize mining as much as possible. During the past few years this trend has gained much prominence in the Porcupine camp. In view of this, the executive of the Porcupine Branch considered that the Mechanical Movement of Muck would be a very timely subject for a Symposium. Accordingly a Committee was formed, with A. K. Douglass, Mine Superintendent for Delnite Mines, Ltd., as Chairman, and the Symposium was held in the Auditorium of the McIntyre Community Building, Schumacher, on March 25th last. Papers dealing with shovel loader and mechanical scraper operation at six of the larger mines of the camp were presented and discussed, and a tabulation was prepared giving data on the machines in operation at a total of eleven mines. The papers and tabulation, reproduced below, will doubtless be of considerable interest to operators of mines in all parts of Canada.

Jan 1, 1948

By N. M. Steven, J. M. Moore, J. L. Kuyper

Mineral exploration and research has led to the identification of four types of tungsten mineralization in the NE-trending, Iargelyensialic, inland branch of the late Proterozoic/early Paleozoic Pan-African Damara Orogen. The mineralization (mainly scheelite) occurs in a terrane (the Central Zone) that is characterized by multiple deformation, greenschist/amphibolite-facies metamorphism and numerous peraluminous S-type granitic and pegrnatitic intrusions. The four major types of scheelite mineralization are (in ascending stratigraphic order of host rock): (1) thin (5 cm to 2 meter) quartz+plagioclase+diopside ± scapolite calc-silicate granofels with fmely disseminated scheelite (scheelite-bearing granofels; SBG) developed as discontinuous intercalations within the calc-silicate rocks of the Khan, Spes Bona, Oberwasser and Kuiseb Formations (Nosib and Swakop Groups); (2) gamet+pyroxene± vesuvianite+scheelite ± fluorite replacement skarns hosted by Okawayo, Karibib and lower Kuiseb Formation marbles in the aureoles of late tectonic, unrnineralized leucogranites; (3) metaturbidite-hosted scheelite- (and possibly wolframite-) bearing tourmalinites, both stratiform and crosscutting, in the Kuiseb Formation located in the 'cleavage fronts' of late tectonic granitoids; (4) scheelite-bearing vesuvianite+quartz+garnet skarnoid rocks (several hundred meters in length) in the calcareous metaturbidites of the upper Kuiseb Formation. These scheelite occurrences were discovered by the follow-up of a large number of tungsten anomalies located during a regional stream sediment sampling program. Detailed mapping, ultra-violet surveys and rock sampling proved to be the most effective surface exploration techniques for locating mineralization; soil sampling and geophysics were of almost no use. The largest, continuous scheelite-bearing skarn of economic interest, Otjua, has a drill-indicated reserve of 250 000 tonnes at 0.53 wt5 WO3 and 8 wt% CaF2•

Jan 1, 1994

By J. B. Mawdsley

"AbstractThe uraninite-bearing deposits in the Charlebois Lake area of northeastern Saskatchewan are unusual and important concentrations of uranium. They were first discovered in 1949 and preliminary development work to the end of the 1951 field season indicates the probability that this will become •another uranium producing district. The deposits are in zones bordering granite masses. These zones are of migmatite (mixed rocks) composed of calcium-rich meta-sediments intruded and replaced by a fine-grained white pegmatite. Locally this pegmatite is replaced by an end fraction which is relatively rich in fine-grained disseminated uraninite; it is these occurrences that constitute the bodies of economic interest.The fine-grained white pegmatite contains plagioclase feldspar more lime-rich than that in the granites of which it is an end differentiate. This extra lime, evidently derived from the intruded sediments, would result in the raising of the temperature of crystallization of the pegmatite-forming magma, thus consolidating it rapidly near the granite contacts as a fine-grained pegmatite. The end liquor containing uranium was evidently locally concentrated in minor fracture zones in these pegmatites. Where no lime sediments were present. the coarse-grained alkaline pegmatites were formed. Their crystallization would not be accelerated and the uranium would tend not to be localized in the pegmatite but to migrate and consolidate at lower temperatures with the end products, possibly in some instances as pitchblende veins."

Jan 1, 1952

By R. D. Browns

In his Budget Speech on March 31, 1 977, the Honourable Donald S. Macdonald expressed concern about the financing of investments through new equity issues. He mentioned the need to render more attractive participation in the equity market by investors in all in come brackets. One of the measures introduced in the budget to accomplish this goal is the proposal to increase the dividend gross-up and tax credit in respect of most dividends received by an individual from Canadian companies. The following comments and tables serve to illustrate the impact of this particular proposal.

Jan 1, 1977

By F. Henríquez, V. Iriarte, L. Vinnett, J. Yianatos, F. Díaz

Metallurgical characterizations of the collective (Cu/Mo) and selective flotation plants were carried out in Minera Los Pelambres, Chile. The selective plant allows the valuable minerals of Cu and Mo to be separated. The evaluation involved two surveys consisting of metallurgical sampling as well as residence time distribution (RTD) measurements to determine load distribution. The RTD data were obtained in real-time by means of the radioactive tracer technique. In addition, metallurgical data was reconciled and supported by effective residence times. In the collective plant, a performance comparison of parallel rougher circuits was carried out, which included a bank of six mechanical cells of 250 m3 and banks of nine mechanical cells of 130 m3. In the selective plant, the Cu and Mo evolution along the plant was evaluated. The results in the selective plant allowed for performance evaluation of mechanical and pneumatic cells in primary flotation. In both plants, mineral losses were evaluated and their relationship with circuit configuration (cell types and circuit layout) was determined. The metallurgical characterization was a powerful tool to evaluate circuit performance and to detect improvement opportunities at industrial scale.

Jan 1, 2015

By A. M. Nordale

Let us first trace a line, mentally, across Alaska and Yukon, starting at a point in the west slightly south of the delta of the Yukon river and from there continuing eastward, loosely following the 63rd parallel of latitude until we have passed beyond the eastern border of Yukon. We will make two pronounced digressions southward to include the greater parts of the Iditarod and Tanana River valleys. That visualized line roughly defines the southern boundary of permafrost. North of it lies a vast region, fully three-fourths of the area of the two territories, which includes Seward peninsula, the great Yukon River basin, and the tractless wastes of the Arctic. During some frigorific cycle in the distant geological past, the ground there was frozen to a depth of many hundreds of feet. How deep the frost actually penetrated is not known, but it has been found to exceed three hundred feet in many places. Nature afterwards provided a perfect insulating cover in the form of heavy moss and dense grass, which has protected the ground from the heat of the sun's rays during the intervening ages. This frozen condition has always been accepted as something indigenous to the North and little thought was given to -it until recently, when the United States Government and, I believe, the Canadian Government, began extensive studies of it, particularly in respect to its effect and bearing on the development of the great oilfields of the Arctic. Within this large region and but a short distance south of the Arctic circle are the three principal producing placer gold fields in the sub-arctic, whose hubs centre at Nome and Fairbanks in Alaska and at Dawson in Yukon Territory. The geological structure and history of the gold-bearing deposits of Dawson and Fairbanks are very similar and probably closely related. They are typical placer deposits produced by stream action during periods of erosion and inundation and subsequently covered with a thick layer of fine, powdery silt mixed with decayed vegetation which, locally, is termed 'muck'. The depth of muck varies from less than 10 to more than 250 feet, with the greater depth near the lateral edges of the valleys. The gravel underlying it is medium in size, well rounded, and composed mostly of quartz and schist. The proportion of sand or fines is approximately 40 per cent. No large boulders and little clay are found, for those districts, as well as that of Nome, have not been subjected to glaciation. The most common bed-rock found is either decomposed or hard schist, but infrequently it is slate, quartz, diorite, or a porphyry. The vertical concentration of the gold is invariably on bed-rock and in the lower few feet of gravel which overlie it. The horizontal concentration or paystreak is roughly parallel to the trend of the valley but does not ordinarily coincide with the course of the present stream. The width of the paystreak usually expands from a few feet at the head of a creek to several hundred feet near its mouth.

Jan 1, 1947

By S. G. Enns, E. W. Yarrow

"Situated about 200 km southeast of Juneau, Alaska, within the lower Stikine River region of northwestern British Columbia, the Galore Creek porphyry Cu-Au deposits are hosted by Upper Triassic to Lower Jurassic alkaline volcanic rocks and comagmatic syenite intrusions. Early and late breccias are also locally important host rocks for mineralization. Of the twelve identified Cu-Au deposits, the most important are the Central zone, Southwest zone and the Junction deposits with a combined resource of 284 million tonnes at 0.67 % Cu.The composition of the intrusive rocks is predominantly silica-undersaturated, alkaline, and metaluminous. Four intrusive suites are identified from field, petrographic and petrochemical data. Variation within suites or lineages can be explained by alkali feldspar fractionation. An oscillation between porphyritic and equigranular intrusions is suggested by the sequence of different intrusive lineages. The youngest intrusive phase is silica-saturated.A complex succession of intrusive and hydrothermal events is demonstrated at Galore Creek, with the most intense alteration and mineralization developing early in its history. In the Central zone, early Ca-K-silicate alteration, dominated by garnet, biotite, Kfeldspar, and anhydrite grades outward into K-silicate alteration. Both are locally overprinted by retrograde sericite± anhydrite± carbonate (SAC) alteration. The most intense Ca-K-si/icate alteration, a magmatic-hydrothermal breccia, and an early syenite intrusion are all coincident with copper mineralization in the core region of the Central zone. However, higher grade mineralization in the zone, exceeding 1 % Cu with more than 0.5 g/ t Au, is typically associated with intense biotite-rich, K-silicate alteration primarily hosted by altered volcanic rocks. The highest gold grades, commonly exceeding 1 g/t, are associated with bornite-rich mineralization situated in the northern and southern parts of the Central zone.Mineralization in the Southwest zone occurs as disseminated chalcopyrite within a late, diatreme breccia and adjacent K-feldspar porphyry. In the other satellite deposits, disseminated chalcopyrite and bornite occur in volcanic rocks with alteration that is similar to the Central zone."

Jan 1, 1995

By Nicholas J. Welham

"The effect of extended ball milling has been studied for two industrial processes: (1) the processing of metal sulphide concentrates; and (2) the carbothermic reduction of ilmenite to synthetic rutile. The plant concentrates were a gold ore with 128 g/t Au of which 8% was non-refractory and a zinc concentrate with copper impurities.The gold concentrate showed complete dissolution of the gold bearing minerals after milling giving almost complete gold liberation. The zinc concentrate showed almost all of the sulphides had solubilized leaving the gangue and elemental sulphur. A study of pure pyrite and arsenopyrite shows that selective dissolution should be possible by a simple leaching process directly after milling.The milling of ilmenite and coal together results in a temperature decrease of 150°C in the subsequent carbothermic reduction of ilmenite, in addition to improving both the rate of reaction and the selectivity of reduction to rutile. IntroductionAlmost all mineral processing plants use mills for the size reduction of particles prior to physical and chemical processing. When continuing beyond size reduction the energy transferred causes deformation, breakage and realloying of particles giving a steady-state particle size. The breaking also causes increasing damage to the crystal structure by formation of smaller grains giving an increasing number of grain boundaries and increasing crystalline defects due to deformation. The increasing number of grain boundaries and defects leads to increased reactivity, which can be seen directly by a reaction within the mill, or indirectly, via a decrease in the subsequent annealing temperature required for reaction."

Jan 1, 1997

Research, whether applied or fundamental, is a human endeavour which increases our understanding of nature. It is insufficient to simply observe, explore, record and classify. It i necessary, as well, to fit the observations into a satisfying theoretical scheme; that is, to synthesize. Two examples of successful research programs in physical metallurgy are di cussed from this point of view. A pessimistic view is taken of the prospects for rapid growth of research activities in the Canadian metallurgical industry. THE term "research" is used indiscriminately to describe any intellectual or experimental activity which leads to a change in society. Proponents of various activities, ex-tending all the way from alloy development to subliminal advertising, use the status of the term for special advantage. With the Canadian Government entering upon a project of support to industrial research, it might be well to determine what definition is most in the public interest. As an academic, I have a rather jealous attachment to the definition that research, whether applied or fundamental, is a human endeavour which increases our understanding of nature.

Jan 1, 1963

By L. Magne, M. Maldonado, R. Varela

Real-time optimization of flotation circuits demands for accurate and reliable measurements to support the decision making process. The collection zone gas holdup is an important variable in this context as integrates the effect of machine and chemical factors on the bubble size and velocity distributions. It has been demonstrated that gas holdup not only correlates with bubble surface area flux, which defines the particle collection rate and recovery in the collection zone, but also with water overflow, a variable which has been related to the froth zone recovery. Therefore, on-line gas holdup measurements provide a reliable alternative to judge efforts leading to the optimization of flotation cells and columns. Estimation of gas holdup in flotation from electrical conductivity measurements has been proposed and extensively used in lab and industrial installations. The approach is based on the application of Maxwell's model, which relates the concentration of a dispersed phase in a continuous medium to measurements of the conductivity of the liquid medium and of the mineral pulp with and without air bubbles included. These measurements require a conductivity cell which covers a representative volume of the flotation cell, and creates a homogeneous electric field throughout this volume that ideally is not affected by the conductivity of the medium. The development of such a cell in the limiting space and geometry of a laboratory flotation cell has been problematic, but a multi-electrode arrangement offers a promising alternative. Electrodes were installed in the flotation cell of a Denver unit; the results of preliminary testing are discussed with a focus on its performance in the measurement of two- and three-phase dispersion conductivity.

Jan 1, 2015

By N. Dave

"IntroductionIn the mineral processing industry, certain minerals such as uranium, thorium and vanadium, etc., are selectively extracted with high degree of purity from solutions containing variety of other impurities by solvent extraction process. This separation process consists of bringing two immiscible or partially soluble liquid phases in contact, where mass transfer of one or more components takes place by ion exchange under certain controlling parameters such as pH, salt concentration and temperature. The processes taking place are primarily physical because the solutes being transferred are ordinarily recovered without chemical change. For efficient extraction more than one stage is required and the solutions are recycled counter currently through other stages. A multi-stage counter current solvent extraction plants essentially consist of four circuits namely: extraction, water wash, stripping, and solvent scrubbing. In extraction circuit the desired mineral is extracted at a certain pH from an aqueous solution onto an organic solvent by bringing them in contact with mixing in large mixer-settler units. The mixed solutions are allowed to settle and separate into component organic and aqueous phases in horizontal settlers by providing sufficient residence time. The solutions are then moved counter currently to other units- the aqueous from the underflow and the solvent organics from the overflow of the settler. The solution streams coming out of extraction circuit are loaded organics and barren aqueous or raffinate solution. The loaded organics are washed with water in a water wash circuit to remove transported impurities from extraction circuit. In the stripping circuit, the desired mineral is stripped selectively from the solvent phase back into an aqueous phase with a stripping agent at a selected pH. The solution stream leaving, stripping circuit are stripped organics and pregnant strip (aqueous) solution. The stripped organics are scrubbed off other loaded impurities with a conditioning solution in, scrubbing circuit and the cleaned solvent is re-used in the extraction circuit.A typical solvent extraction plant for uranium extraction and purification at Agnew Lake Mine is described in this chapter."

Jan 1, 1989

By P. Henry

Hydrometal provides an adequate technology to reintroduce lost metal units into the industrial cycle, thereby saving resources and energy, while keeping the environment cleaner. Two case studies of our integrated hydrometallurgical recycling facility (Hydrométal) in Belgium are discussed.(I) Recycling of Cu-Co cement generated at the second purification step of zinc sulfate solution. (II) Recycling of lead complex materials from the lead industry.

Jan 1, 2008

By J. H. Canterford

The nickel industry in Australia has followed the general pattern apparent in many other regions - lots of ups and downs, successes and failures, but always plenty of challenges. Some of these can be attributed to local geographical and infrastructure factors, others to a healthy mix of corporate good luck and management countered by decisions that, in retrospect, were less than optimum. The roles of several entrepreneurs have certainly added plenty of spice! In terms of processing technologies, there was an initial heavy reliance on the use of "off the shelf' commercially proven processes such as ammonia leaching of concentrates and mattes, and flash smelting. Over the past decade there has been an increasing dominance of plant modifications and process technologies that have been developed "in house" in order to enhance project economics and exploit lower grade and more complex resources. This presentation provides an overview of the past 40 years of the major developments in the Australian nickel industry and concludes with some guesses as to where we will be in another decade or so.

Jan 1, 2005