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By J. S. Fox

Major-element data for unaltered, unmineralized felsic host rocks from a number of stratigraphically simple, massive volcanogenic Zn-Cu(-Pb) sulphide deposits of low metamorphic grade have been compiled. The petrochemical affinities of these host rocks have been determined (by standard means and by discriminant analysis) and compared. This comparison indicates that volcanogenic deposits in felsic terrains are not restricted to the classical calc-alkaline rock association as previously thought, but can actually be hosted by rocks showing a range of iron content. There is a positive correlation between differentiation trend and are tenor. Zn-Cu ores usually have iron-rich felsic hosts (most Canadian Shield deposits); Pb-Zn -Cu ores have iron-poor felsic hosts (Japanese, Iberian and Tasmanian deposits). This parallels the antipathetic relationship between iron content and background lead levels evident in young, unmineralized, island arcs as well as in many older belts. Correlations between differentiation trend on one hand and massive ore mineralogy and the relative proportions of various rock type (including rhyolite, quartz-porphyry and coarse pyroclastic rocks) on the other are also evident. It is concluded that the recognition of a calc-alkaline differentiation trend cannot be used as a prospecting guide, as has previously been proposed. However, in view of the above correlations, the recognition of a given trend may aid in the formulation of an effective exploration philosophy.

Jan 1, 1979

By F. R. Archibald

SINCE the opening of the Beattie mine, in 1933, the concentrate produced by flotation has been considered refractory. As the gold extraction by cyanidation was poor, the concentrate, during the first four and a half years of operation, was shipped to a smelter for further treatment. After the installation of the cyanide plant, in 1934, seventy per cent of the gold in the concentrate was recovered before shipment to the smelter. In 1937, a roasting plant was built so that treatment might be complete at the mine. Much experimental work had been done by a number of investigators prior to the installation of the roasters, but none of them had seriously attempted to identify the causes of, or the elements responsible for, the refractory behaviour of the concentrate. Intensive investigation in this direction commenced in the Beattie lab-oratory in July, 1938, has led not only to the identification of several causes contributory to the refractory behaviour, but also to revisions in procedure and principles with respect to roasting Beattie concentrate in particular and arsenical concentrates in general. The accuracy of the identification of these causes and the soundness of the principles is borne out by interpretation of roasting plant records, by improvements and simplification since applied. to plant operation, and also by laboratory and test-plant results on arsenical concentrate produced by another mine. It is the purpose here to present an account and interpretation of the laboratory investigation, together with a correlation of laboratory and plant results. Incomplete extraction of the gold by cyanidation after roasting is due primarily to the nature of the material roasted, and secondarily to the manner in which it has been roasted. There is a possibility that better extraction may be obtained by improvements in both particulars.

Jan 1, 1939

By R. Q. Honaker

A significant problem in ultrafine particle classification is the significant amount of submicron particle by-pass to the coarse particle stream. In classifying cyclones, submicron particle by-pass to the underflow stream can be reduced by decreasing water recovery. Past studies have shown that a reduction can be realized when the feed solids concentration is increased or the apex diameter is reduced. However, both adjustments tend to increase the particle size cut point and negatively affect classification efficiency due to the impact on slurry rheology. The addition of a viscosity modifier to the feed stream of a classifying cyclone improved the classification performance and decreased the particle size cut point over a range of feed solids concentrations. The detailed test program investigated the use of the modifier in conjunction with varying apex diameters to identify conditions that minimize ultrafine by-pass. With small apex sizes, roping conditions were readily eliminated by the addition of viscosity modifiers. The addition of the modifier had no deleterious effect on froth flotation performance, which commonly serves as a downstream separation process. The fundamental and practical benefits of viscosity modifiers in classification processes are discussed in this publication.

Jan 1, 2006

By A. Villanueva

The effect of High Pressure Grinding Rolls (HPGR), as a preceding stage to a conventional ball mill circuit at PT Freeport Indonesia?s C1/C2 concentrators, has been studied in terms of downstream grinding efficiency and circuit performance. When milling the product from the HPGR, mill capacity increased by 21% for the same product grind size, when compared to processing similar ore from a conventional crushing circuit. This achievement is a result of several reasons, among them: reduction in feed size (F80), fines generation beyond the proportional reduction in F80, reduction in ore hardness induced by HPGR comminution mechanism, optimization of the recycle system of the HPGR and ball string optimization in the ball mill circuit given the new feed to the mill.

Jan 1, 2012

By J. Keith Seidler, David R. Lentz, Douglas C. Hall, Nicholas Susak

Abstract - The Ta-Nb-Zr-REE-rich McKeel Lake alkali granite pegmatite-aplite dike swarm is hosted within the late Silurian multiphase alkali granite intrusion (Welsford) near Browns Flats in southwestern New Brunswick. A steep easterly dipping series of pegmatite-aplite dikes trending 170º can be traced 150 m along strike; they are up to 40 cm wide, closely spaced (10-20 cm apart), and interconnected by narrow branching dikelets that generally trend perpendicular to the overall strike direction. The Welsford intrusion has mantle A-type affinities characterized by enrichment of Zr, Ta, Nb, Th, and rare earth elements (REE). Two separate sets of dikes have been identified: (1) an unmineralized fine-grained porphyry, which occurs at depth and seems to be the youngest intrusive phase; and (2) a mineralized pegmatite-aplite dike swarm (419 ± 20 Ma) that crops out at surface. The mineralized pegmatite-aplite dikes likely represent a late magmatic, highly fractionated phase of the Welsford intrusion. XRF and INAA data indicate that the Welsford intrusions and related pegmatite-aplite dikes show elevated levels of Ta (74-220 ppm), Nb (750-3,040 ppm), Zr (1,450-36,000 ppm), Y (540-3,070 ppm), Th (170-870 ppm), U (60-250 ppm), Ce (430-1,950 ppm) and Yb (110-290 ppm). Electron microprobe analysis of two samples identified Ta-Nb- and REE-rich phases: euxenite, fergusonite, aeschynite, (Y)-aeschynite, and a REE carbonate.

Jan 1, 2005

By Laxman M. Amaratunga

Laboratocy flarmnability tests were perfonned on dust samples from Fraser Mine in a 1.2 L Lindenburg horizontal tube furnace to detennine the percentage of sulphur oxidized during ignition. The explosion pot ential of sulphide dusts depends on their degree of spontaneous oxidat ion, which was measured by the quantitative analysis of so2 gas released during ignition. Test results indicated that dusts with low sulphur content could exhibit a higher degree of oxidation than a sample with high sulphur content. txlst characterisation using image analysis techniques suggests that the structure and the texture of dust are important factors influencing the explosibility of sulphide dust at ignition temperatures. Therefore for safe mine operations% sulphur content cannot be considered as a reliable single index that could be used to predict the potential of a sulphide dust explosion. Physical, chemical and mineralogical characterisation of dust plays an important role in the detennination of suitable indices for the prediction and prevention of sulphide ore dust explosions.

May 11, 1988

By H. Arima, Y. Kudo

In general, the iron content of zinc leach residue produced by sulphuric acid leaching from calcine is disposed as jarosite or goethite into a tailing dam. More recently, these iron residues have been treated pyrometallurgically to avoid waste disposal. The Iijima refinery selected a different zinc leach residue treatment process for iron control when it was established in 1971. The Iijima refinery is the only plant in the world that has processed a zinc leach residue by the combination of SO2 pressure leaching and O2 pressure hematite precipitation. The process enhances zinc recovery and recovers gold, silver, copper, lead and rare metals in saleable by-products. This paper focuses on the two stages of autoclave application in the zinc leach residue treatment process. The detailed flowsheet and recent advancements to improve the quality of by-products are discussed.

Jan 1, 2004

By The Mill Staff

"IntroductionCOMMENCEMENT of operations at the new No. 7 shaft and 10,000-ton mill at Creighton mine was a major step in the programme of conversion to all-underground mining by the International Nickel Company of Canada, Limited. Planned ten years ago, the orderly transition has been greatly speeded-up to offset the heavy drain on production imposed by World War II and also to meet the increased demand for nickel caused by the current international situation. Development of new mining methods, and process changes in the reduction plants, have made possible the economic recovery and utilization of ore of lower grade than formerly used and of varying metallurgical characteristics. By 1953, when the Company's open-pit mining operations are scheduled for completion, the hoisting capacity of its five underground mines in the Sudbury district will have been increased to 13,000,000 tons per year, compared with 5,700,000 tons of underground ore hoisted in 1950.Two types of ore occur at Creighton. One is a breccia and stringer type that contains a high percent-age of massive sulphides and is located in sheets along shears and in large and small pockets on the underside of the main norite mass; the other type, forming the main part of the ore zone, is mineralized norite that occurs as a •sheet up to 400 feet thick overlying tl1e breccia ore. In both types of ore the minerals of economic interest are pentlandite, which is intimately associated with pyrrhotite, and chalcopyrite. Early mining was confined to the breccia ore; this ore was mined by open stoping methods. The hanging-wall was later allowed to cave, with the result that the old stopes are now filled with caved low-grade ore."

Jan 1, 1952

By C. L. Monroe

It has been the custom in recent years to look upon Atlin as a worked-out placer camp. This is a conception, however, which is far from the real situation. The placer-gold deposits of Atlin are today, after thirty-one years of continuous working, a field well worth the attention of the mining world. It is true that the shallow diggings (the 'easy money') have been practically cleaned out, but although there have been perhaps ten millions, or more, in gold already taken from the district, there are still many more millions left in the creek beds . A conservative estimate of the gold still remaining in one creek alone, Spruce creek, for a long time known as the 'prospector's meal ticket', would place the amount at anywhere from fifteen to twenty million .dollars, and there are a number of other creeks that have never been thoroughly worked, and some only partially prospected. That the true situation is beginning to be recognized by those who are on the lookout for a profitable field for investment, is born out by the fact that, within the last few years, New York capital directed by Mr. Charles V. Bob, who is also responsible for the opening up of the Engineer mine, has installed on Pine creek, where the first discovery of gold in the district was made, one of the largest hydraulic mining plants on the continent, utilizing six miles of the old hydraulic ditch of the Discovery Mining and Power Company, and over two miles of pipe line. On Boulder creek, where already two millions have been taken out, the Consolidated Mining and Smelting Company are on their third year of development work in opening up the unworked ground, while on Otter creek a newly organized French company have started a plan of development which will involve an expenditure in the neighbourhood of $200,000, and two or three years' work, before they can hope to find gold in paying quantities. It is probably safe to prophesy that placer gold will be produced in the Atlin district for the next fifty years

Jan 1, 1929

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 J. Stiksma, R. Kalanchey, M. J. Collins, G. Owusu, R. Raudsepp, K. R. Buban, L. A. Barta, L. Masters

This paper describes the results of testwork for the treatment of Ambatovy laterite by an acid pressure leach process, with recovery of the soluble nickel and cobalt values as mixed sulphide intermediate by precipitation with hydrogen sulphide, and subsequent refining of the mixed sulphide to nickel and cobalt metals. These process development studies were carried out primarily in 2004, as part of a bankable feasibility study for the Ambatovy Nickel Project.

Jan 1, 2004

By A. Kapoor, L. Morin, S. Mortazavi, P. Béedard, Gould. W. D., A. Kuiper

The degradation of thiocyanate in a simulated gold mill effluent was studied using a laboratory scale rotating biological contactor (RBC). Complete SCN- removal was obtained at temperatures of 8 and 12°C, and a hydraulic retention time of approximately 3.3 h. The NH4+ produced by thiocyanate hydrolysis was oxidized by nitrifying bacteria to NO2 and NO3-. The HS- produced by thiocyanate hydrolysis was chemically and biologically oxidized to elemental S, which was subsequently biologically oxidized to sulfate. Incomplete sulfur oxidation occurred in the RBC, particularly at 8°C and elemental sulfur deposition was observed on the RBC disks. The RBC feed exhibited toxicity to rainbow trout but the RBC was effective in removing the acute toxicity of thiocyanate.

Jan 1, 2005

By A. E. Wraith, R. Harris, J. Qiu, R. Parra

Small pilot scale experiments have shown that it is possible to almost fully eliminate the minor elements (ME), namely As, Sb, Bi and Pb contained in smelter dusts by vacuum calcination of mixtures of the dust with sulphidizing agents such as dirty copper concentrate or elemental sulphur at 900 °C and 80 +/- 30 Pa for 90 minutes. The products of this calcination are a residue comprising a purified mixture of copper containing compounds along with the gangue constituents and a high sulphur condensate comprising a mixture of the minor element compounds. In particular, the Cu:ME ratios of the concentrate and dust were increased from 250 and 50, from 28 and 12 and from 36 and 8 to roughly 3000, 3000 and 100 for the calcine, for Bi, As and Sb, respectively. It has also been calculated that (i) the copper content of the vacuum calcine may be recovered by feeding it into a Peirce-Smith converter during its slag blow, and (ii) the resulting recycling could increase the minor element treatment capacity of a smelter by 100 % while also reducing the blister As content by a factor of three. The experimental results are briefly discussed and a treated dust recycling option is examined. Example operating conditions are presented and available commercial technology for the vacuum calcination of the mixtures is reviewed.

Jan 1, 2007

By T. Grammatikopoulos, SGS Canada Inc.

"The Nechalacho rare metal deposit, located in the Northwest Territories, Canada, is currently being taken through Feasibility Study by Avalon Rare Metals Inc. QEMSCAN analysis and supplementary electron microprobe analysis were utilized to identify and quantify the mineralogy of the deposit, and determine REE distribution among the minerals. QEMSCAN mineralogy was performed to provide textural information on the mineralization, determine the variability of the ore and identify REE domains, and the liberation and association of the REE minerals. The sample matrix consists predominantly of silicate minerals. The REE minerals include allanite, monazite, synchysite, columbite, fergusonite, and bastnaesite. Zircon is present in considerable amounts and is a REE carrier. Fergusonite and zircon account for most of the HREE, and monazite, allanite, synchysite and bastnaesite the LREE. QEMSCAN mineralogical data is extremely valuable in assessing the mineralogy of the ore. The data are implemented to define the mineralogy of the ore body, support metallurgical test work, and predict recoveries and grades.INTRODUCTIONThe term rare earth elements (REE) is used to describe the 15 lanthanide elements or metals and, more recently, the metals yttrium and scandium, which display similar physical and chemical properties.Economic and potentially economic REE deposits form two main groups, a more commonly occurring “light rare earth element” (LREE) group containing lanthanum, cerium, praseodymium, neodymium, and samarium and a less commonly occurring “heavy rare earth element” (HREE) group which, in addition to the LREE, contains elevated concentrations of the more valuable REE, europium, gadolinium, terbium, dysprosium, holmium, yttrium, erbium, thulium, ytterbium, lutetium and scandium. The first group is hosted primarily by carbonatites and the second by highly alkaline (Na + K > Al) silicate igneous rocks. The LREE are produced mainly from bastnaesite, monazite, etc., while HREE are produced almost exclusively from low-grade secondary ion adsorption clay deposits in which the REE are adsorbed onto the surfaces of kaolinite and halloysite, clay minerals produced by the weathering of granite and sediments. HREE are also found in fegusonite, zircon, xenotime, etc but are not produced presently from these minerals. China is responsible for 97% of the World’s production of the REE, mainly from the giant Bayan Obo, carbonatite-related deposit and from the clay deposits mentioned above.Quantitative automated mineralogy is increasingly being applied to ore deposits. It helps users to understand and improve mineralogical parameters for geological and metallurgical purposes. Data include textural characterization, to quantification and distribution of ore and gangue minerals, liberation and association of the REE minerals. The data can be used to define mineralogical domains and predict the metallurgical response of the ore (Gunning, de Souza, & Grammatikopoulos, 2009)."

Jan 1, 2012

By J. R. Goode

ABSTRACT Aurora Energy Ltd. is considering a 10,000 t/d process plant to produce 97 million lb (43,998,460 kg) of U3O8 over a 17-year project from uranium deposits in coastal Labrador. This paper summarizes the test work, mostly done by SGS Mineral Services in Lakefield, Ontario, and the economic studies supporting flowsheet selection. The proposed flowsheet includes semi-autogenous grinding (SAG) and ball milling, acid leaching using air/SO2 as an oxidant, and resin-in-pulp (RIP) extraction of uranium from the leached slurry. Other unit operations examined include ore sorting, heap leaching, liquid- solid separation, solvent extraction, and nanofiltration for eluate upgrading. We also review the extensive environmental test work and studies that were completed.

Jan 1, 2012

By J. E. Hawley

"IntroductionA STUDY of the trace elements in the ash •of coals from nine seams in the Sydney coalfield, Nova Scotia, was undertaken at the suggestion of Dr. W. A. Bell, Geological Survey of Canada, as a part of a larger study of these and other Nova Scotia coals being made by the Geological Survey and the Nova Scotia Department of Mines under the direction of Dr. P. A. Hacquebard.The main purpose of this investigation has been to •determine if a knowledge of the trace element distribution might be of assistance in the recognition of individual seams, the distinction of which is not always easy or positive in folded and faulted strata by ordinary stratigraphic and structural means.The study has been so conducted as to afford information on the variation of trace elements in individual petrographic intervals or divisions in each of the seams examined, intervals determined by Dr. Hacquebard on the basis of their banded ingredients, vitrain, clarain, durain, fusain, etc, as observed under the microscope in polished sections. The results, as well, indicate the trace element composition of the coals of the area as a whole, and quantitative data for fifteen elements are given, along with concentrations of thirteen other elements, stated in terms of intensity ratios. Data on distribution of germanium, though considered here along with other elements, are dealt with elsewhere*."

Jan 1, 1955

By G. Shen, W. R. Tyson

In most fracture toughness test standards, such as ASTM E 1290 and BS 7448, crack-tip opening displacement (CTOD) is measured by using three-point bend (SE(B)) or compact (C(T)) samples with deep cracks. The loading mode and crack depth in these tests sometimes are different from that of pipelines. Pipelines usually have shallow defects and experience tensile loading when the supporting ground moves. As a result, the CTOD measured by these samples is lower than that of pipeline in tension. Recent researches suggest using single-edge-notch tension (SE(T)) samples to measure fracture toughness for pipelines. In the present study, shallow and deep SE(T) samples under fixed grip loading were analyzed by using the finite element technique. An equation to relate the CTOD to the area of the load/plastic crack mouth opening displacement (CMOD) is proposed. With this equation, the CTOD of a SE(T) sample can be evaluated by measuring the area under the load/plastic CMOD curve of a SE(T) sample.

Jan 1, 2005

By D. D. Macdonald, G. Engelhardt

The accumulation of damage due to localized corrosion [pitting, stress corrosion cracking (SCC), corrosion fatigue (CF), crevice corrosion (CC), and erosion-corrosion (EC)] in complex industrial systems, such as power plants, refineries, desalination systems, etc., poses a threat to continued safe and economic operation, primarily because of the sudden, catastrophic nature of the resulting failures. Of particular interest in managing these forms of damage is the development of robust algorithms that can be used to predict the integrated damage as a function of time and as a function of the operating conditions of the system. Because complex systems of the same design rapidly become unique, due to differences in operating histories, and because failures are rare events, there is generally insufficient data on any given system to derive reliable empirical models that capture the impact of all (or even some) of the important independent variables. Accordingly, empirical models have generally failed to provide a robust basis for predicting the accumulation of corrosion damage in complex systems under realistic operating conditions. The alternative prediction philosophy is determinism, in which the development of damage is described in terms of valid, physico-electrochemical mechanisms with the output being constrained by the natural laws. The differential damage is then integrated along the corrosion evolutionary path for the system (i.e., over the future operating "history") to yield the desired integrated damage, which is the quantity that is most useful to an operator. In this paper, we review the theory of predicting corrosion damage within the framework of Damage Function Analysis (DFA), with particular emphasis on the pitting of aluminum in chloride solutions and on the accumulation of damage from SCC in Type 304 SS components in the primary coolant circuits of Boiling Water (Nuclear) Reactors (BWRs). These cases have been selected to illustrate the various phases through which localized corrosion damage occurs.

Jan 1, 2005

By J. Álvarez, J. Mesías, C. O. Gómez

"Operations routinely run flotation tests in laboratory mechanical cells to determine adjustments to plant operation based on feed flotation response or the effect of new reagents and dosages. The metallurgical results of these tests are certainly affected by changes in bubble size, which simultaneously impact the recoveries of the collection and froth zones. It is known that bubble size depends on the characteristics and operation of the machine in use, particularly on the gas flow rate delivered to the unit and the selected frother type and dosage. Although flotation rate constants have been related to bubble size, bubble surface area flux seems to be a more fitting variable to correlate flotation kinetics and cell performance, as it integrates bubble size and superficial gas velocity effects. However, although some evidence has been provided, a categorical relationship between cell recovery and bubble surface area flux has not been established. Our interest is to demonstrate this relationship to use it as a basis for developing soft sensors to track on-line collection zone recovery in cells. Flotation tests were designed to produce Cu concentrates for a range of bubble surface area flux values, obtained through changes in frother concentration at a constant gas flow rate, and by increasing gas flow rate at the same frother concentration. The tests were run on samples prepared from an ore batch supplied by a local operation, following strict grinding and flotation procedures, with a shallow froth to approximate cell recovery to that in the collection zone. Bubble sizes were determined using the sampling-for-imaging technique developed at McGill. The results unequivocally showed a consistent positive correlation between cell recovery and bubble surface area flux, and significant variations in performance when frother addition and gas flow rate were changed.INTRODUCTIONMineral flotation is a separation process to produce concentrates of valuable minerals by selective attachment of particles to the surface of bubbles. The process is carried out in machines where air is injected through a mineral pulp to form bubbles, and operated to create two zones: a bottom one (collection zone) where bubbles are continuously generated under conditions adequate to form bubble-particle aggregates by collision of the rising bubbles with suspended particles; and a top one (froth zone) where bubbles and bubble-particle aggregates continue to rise while concentrating and forming a froth layer for water and entrained particles to drain back to the collection zone, before overflowing as a concentrate stream. The phenomena occurring in these zones are complex and, in many cases, interactive, as they simultaneously affect stages of the particle separation sequence occurring in both zones. Although there have been significant advances in instrumentation to characterize particle and bubble populations, these have not resulted in knowledge to explain or models to describe phenomena from fundamental principles. Measurements continue to be limited to the development of empirical models for predicting the effect of operating variables on performance."

Jan 1, 2016

By R. C. Wallace

It was to be expected that the convening of the first Empire Mining Congress in June, 1924 in the city of London would turn men's thoughts very definitely to the question of exploring the mineral resources within the British Empire, the examining of her strength and her weakness in mineral material, and the consideration of steps that might advisedly be taken to strengthen her trade in minerals. That expectation was in part realized, though in the British way of presenting the case, and permitting the inferences to be drawn by implication. The opening address by the President of the Congress, to whom the Empire meant so much, gave a résumé of the contributions to the mining industry which were being made by the constituent parts of the Empire. The papers from the Institutes in Australasia, South Africa and Canada provided the details of resources and practice: while the individual contributions to the proceedings dealt with those phases of the mineral industry which are fundamental to the economic strength of British people, or to the health and well-being of the workers. While the subject matter thus presented was British mineral resources, and while the first consideration was the co-ordination and co-operation of British enterprise throughout the world, there emerged very clearly the wider viewpoint that the discussions had to do with a world industry, and with the contributions that that industry was making, and could further make, to the advancement of civilization irrespective of national boundaries, the world over. The invitations to representatives of the mining industry from the United States to participate in the Congress, and the warmth of approval which that participation evoked, were indications that such a congress cannot to-day be merely national in scope, and that trade in minerals, as in other natural resources, cannot be confined within national boundaries, but will seek its channels, unless artificial obstructions are too great, where the natural channels already exist.

Jan 1, 1925