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By A. Yoshida, H. Miura, S. Yamaguchi, Y. Oyama

A discussion is given on the ionic equilibria and precipitation reactions in seawater based on thermodynamic analysis, in order to understand the solubility of nutrient salts from dephosphorization slag for marine phytoplankton. Solubility of constituent ions in aqueous solution in equilibrium with solid phases are determined using thermodynamic data. It is proposed that CO2 potential defined as log Pco2 should be considered as an additional parameter to the Eh- pH diagram for the ionic equilibrium of slag components in seawater, since magnesium and calcium carbonate precipitation reactions determine the solubility of ligand ions in nutrient salts, such as phosphates, silicate, and sulfate.

Jan 1, 2004

By J. Aguilar-Santillan, H. Balmori-Ramirez, R. C. Bradt, I. Vernet-Patiño, F. Cunha

Kyanite is an alumino-silicate mineral that has been widely used for the production of refractory products for industrial applications. Kyanite provides a high alumina content, it readily produces mullite during firing, good hot strength of products and can be adapted to produce dimensional stability of products during firing. This research addresses the application of kyanite in mixes to produce (0 dense mullite aggregates with the addition of alumina, (ii) dense composite refractory aggregates of forsterite / spinel with additions of magnesia, and (iii) dense cordierite aggregates with the addition of talc. Effects of attrition milling and conventional ceramic processing are addressed as they affect the properties of these unique aggregates.

Jan 1, 2004

By G. Tozsin

A six-stage sequential leaching procedure was used to assess the leachability of heavy metals from waste rock in Antamina Mine. Sequential extractions procedure is well established for fine and small (? 1g) samples. However procedures for coarse and large test samples are lacking. This study presents results of the sequential leaches tests conducted on relatively coarse and large representative samples in terms of the availability and mobility of metals. Selective chemical reagents were used to extract metals from six different fractions where metals released with each subsequent extraction are believed to be bound tighter than those released in prior steps and therefore less likely to be leached.

Aug 1, 2013

By A. L. Williamson

Bio-mining is a cost-effective, energy efficient and potentially environmentally protective method of exploiting a variety of ore deposits, from high-grade base metal deposits of nickel to lower-grade uranium and rare earth deposits such as are found in the uraniferous quartz-pebble conglomerate beds of the Quirke Syncline, Elliot Lake, Ontario. The effectiveness of bio-mining in Elliot Lake depends on the success of bacterially-influenced dissolution of metals of economic importance. The determination of both the dissolution efficiency and rate controls for uranium and rare earth elements from bio-extraction processes is critical to assess the potential for success of bio-mining along the Quirke Syncline. This poster provides an overview of proton-mediated biogeochemical dissolution of more than 50 elements, including uranium and rare earth elements from samples of the low grade uraniferous ore collected as drill core from the Elliot Lake area. The elemental data is quantified using advanced spectroscopic tools (ICP-MS and ICP-AES) to analyze solutions obtained from a series of environmentally controlled biologically-mediated uranium ore extraction experiments. The findings are being to guide design of larger scale bio-leaching experiments to further assess the potential for success of bio-mining along the Quirke Syncline.

Aug 1, 2010

By P. R. Stephenson

Mining projects depend on the amount and quality of the mineral reserves, which in turn depend on the amount and quality of the mineral resources. Only Measured and Indicated Resources may be converted to mineral reserves and Inferred Resources may not, with certain exceptions, be used in economic studies. Responsibility for the estimation of mineral resources rests with the Qualified Person (QP) and there is a wealth of literature, text books and case studies to guide the QP. Responsibility for the classification of the mineral resources also rests with the QP. While there is some industry guidance and common practice on approaches to resource classification on which the QP can draw, the process is (or should be) heavily dependent on the exercise of judgement by the QP. However, this inevitably leads to situations where, for example, one QP?s Inferred Resource is another QP?s Indicated Resource. If the QP?s judgement is poorly reasoned or illogical (as is sometimes the case), it can have a major impact on the project, often with substantial cost or value implications. Project managers and company executives should not unquestioningly accept QP?s classification decisions and should apply the same intensity of due diligence that they apply to other critical elements of the project.

May 1, 2011

By Steven Dempsey

Overview What is Tubbing? A look at Cigar Lake Tubbing Design The Tubbing Installation Backwall Grouting

May 1, 2013

By Sina Mostaghel, M. Guo, E. Klaffenbach

The current paper is focused on evaluating the behavior of copper in a copper production slag and the assessment of metal recovery possibilities. For this reason, thermodynamic calculations were carried out to determine the influence of parameters such as slag composition, temperature and oxygen partial pressure on recovery of non-ferrous elements. It was found that the formation of a solid face centered cubic (fcc) phase, mainly consisting of iron, limits the extent of reduction that can be achieved for an industrial process. However, it could be discovered that solubility of iron in the Cu-rich liquid alloy strongly depends on presence of other elements, particularly arsenic. As part of the results of this study, the solubility of Cu in the slag at onset of fcc phase formation is presented as function of temperature, oxygen partial pressure and concentration of MgO and CaO. It was concluded that lower temperature (1200°C) and higher CaO addition (16 mass-% in this study), would result in the highest achievable copper recovery from slag. INTRODUCTION Copper slag is produced as a by-product of the copper production process. The slag is still containing a high amount of copper and other valuable metals. This demands further treatment of the slag as a secondary source of metals. In addition, the physical/mechanical properties of slag allow its use in several applications such as hydraulic engineering, civil engineering, as an abrasive and many more. These applications help reducing the use of natural resources like rock and sand. By decreasing the content of heavy metals such as Cu, Pb, Zn and As in the slag, its application in abovementioned fields becomes more attractive as the probability of releasing these elements to the environment is further reduced. To develop a pyrometallurgical slag reduction process, it is necessary to understand what describes the end point of the reduction. This point is expected at maximum copper recovery without facing operational challenges. Existing literature provide some information on the effect of different parameters such as temperature or concentration of different slag formers, on solubility of copper and heavy metals in different phases. However, due to complexity of industrial slags, equilibrium experiments and accurate thermodynamic modelling are essential to be able to reliably predict the behavior of different elements in the system and determine the end-point of reduction.

Jan 1, 2019

By P. W. A. Walker

"The Riviera tungsten occurrence in the Cape Province of South Africa was discovered in October 1979 as a result of stream-sediment panned concentrate sampling. The Cape age granite and late Precambrian Malmesbury Group carbonates and chlorite schists which it intrudes and which host the mineralization are covered by between 10 m and 30 m of Tertiary/Recent alluvium and clay. The scheelite/powellite and molybdenite mineralization occurs in a greisenized granite cupola with an overprint of porphyry-type alteration as well as in minor skarns. The ore reserve is estimated to be 46 million tonnes at an average grade of 0.216% W03 and 0.020070 Mo. The deposit is uneconomic at current tungsten prices. IntroductionDuring the 19705, Union Carbide Corporation was a major producer, processor and supplier of tungsten and derivative products to end-user manufacturing industries. The corporation owned and operated two tungsten mines in the United States, and one in Brazil, and operated a plant in the United States which produced ammonium paratungstate (APT) which is an intermediate product in the production of tungsten wire and tungsten carbide for cutting tool insets and hard facings. In 1975 the three mines were ageing with short-life reserves and high production costs. The world market for tungsten was buoyant and prices, in constant dollar terms, had risen steadily over the past 15 years (Fig. 1).It was against this background that a decision was made to explore for tungsten in North America, South Mrica, Australia and Brazil."

Jan 1, 1994

"The ore currently being milled at Delnite is a high pyrrhotite ore with the gold intimately associated with the pyrrhotite. To get maximum recovery of the gold with the lowest reagent cost, it is necessary to keep the pH as low as possible In the laboratory the best results were obtained with a pH of 10 but in the plant it was found that a pH of 11 was the minimum practical pH. With the n1anual control it was difficult to maintain this figure.The Mines Branch had a conductivity probe (see Fig. 1), developed by Dr. G .G. Eichholz that they wished to try out in plant operation.On June 17, 1963, the probe with all necessary control equipment was installed in the regrind circuit (see Fig. 2) at Delnite Mines. Crushed quick lime is fed at this point but it is also necessary to feed hydrated li1ne at two other points in the cyanide circuit in order to maintain the pH close to 11. 0 throughout the circuit. Only the feeding of the quick lime at the regrind mill was controlled in this test.One thing that concerned me with the operation of the probe was whether the reading on the probe chart would correspond to the pH. A look at the graph accompanying this paper will show that except for very minor variations the graphs of the chart reading and the pH reading are parallel. The upper graph shows that the pH reading and the lime titrations also correspond and that the cyanide titrations appear to have little effect on the pH reading.Table 1 gives the results obtained for the two months before and after the instal1ation of automatic control as well as the two months of control. Unfortunately there was a decided change in ore just after the automatic controls were removed. There was much less pyrrhotitc in the ore than usual thus changing the need for lime and cyanide."

Jan 1, 1964

By M. B. McClenaghan

"The Ontario Geological Survey completed a regional till sampling project between 1984 and 1988 in the Black River Matheson (BRiM) area of northeastern Ontario. The project was designed to aid mineral exploration in the area by documenting the Quaternary stratigraphy and by providing a database of till geochemistry. This paper summarizes the results from the sonic overburden drilling component of the BRiM project carried out in areas of thick drift (> 5 m). Results from till sampling in areas of thinner drift (<5 m) have been presented in a separate paper. Approximately 1100 till samples were collected from 225 sonic drill holes. For each sample, the non-magnetic heavy mineral (>3.3 S.G.) and fine (-250 mesh) till fractions were analyzed geochemically and visible gold grains were recovered by panning.Gold and other multielement geochemical data were plotted using proportional symbols to highlight anomalous areas and to demonstrate how to evaluate and interpret a very large geochemical dataset. Thresholds for identifying anomalous concentrations of Au in till samples, defined using the 95th percentile, are 1500 ppb and 12 ppb for the heavy mineral and fine fractions, respectively. The heavy mineral fraction of older ti1ls and to a lesser extent, Matheson Till, display a number of significant gold anomalies in the study area, which in a few cases, are associated with base metal anomalies. The vertical position of gold anomalies in Matheson and older ti1ls varies from directly on bedrock to several meters above the bedrock surface and can provide information of relative ice transport distances."

Jan 1, 1994

By P. Amelunxen, E. Herrera, L. Hill, J. Vanderbeek

It is well-known that the particle breakage mode that occurs in a semi-autogenous mill is significantly different from that which occurs in a ball mill, enough so to warrant very different lab scale breakage tests and scale-up models. This phenomenon, at the plant scale, leads to changing process constraints depending on the particular properties of the ore. For example, hard or coarse ores might bottleneck the SAG/AG mill throughput, while the ball mills might constrain throughput when milling soft or fine ores. Because the power draw of a ball mill is fairly constant compared to that of a SAG/AG mill, periods of SAG/AG mill bottlenecks lead to increased ball mill circuit specific energy consumption and a finer grinding circuit product size, which together constitute a loss of efficiency of the overall process. Because HPGR circuit throughput is less sensitive to changes in ore hardness, this situation is less common or severe in those circuits. Furthermore, the ball mills are somewhat decoupled from the upstream crushing circuits through the use of surge bins, which also helps to mitigate this effect. As a result, ore hardness variability constitutes a significant cost penalty that should be applied to SAG mill/ball mill/pebble crusher SABC circuits when evaluating the relative economics of different grinding circuit configurations. Nevertheless, the issue is by-and-large ignored, because most current HPGR trade-off studies are based on averaged ore hardness parameters. This paper provides an estimate of the magnitude of this penalty for a typical operation by using Monte Carlo simulation methods and plant data from Freeport-McMoRan’s autogenous, semi-autogenous, and HPGR-based comminution circuits. A case study from an in-house 96K t/d sulphide project is presented to illustrate the concept. It was found that by including variability effects, the trade-off NPV of the HPGR circuit over that of the SAG mill circuit increases to $84 million from negative $33 million, effectively reversing the original decision of selecting a SAG mill circuit for the fixed hardness case.

Jan 1, 2012

By T. Gonzales, M. Maleki, M. Caçador, B. Climenhaga, H. Ghorbani

The campaign life of furnaces in the copper making industry is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper monitoring and assessment of the existing conditions and safe remaining life of the vessels and their refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a typical fitness-for-service assessment of a rotary vessel shell in order to extend the campaign life of copper making furnaces and enhance safety. The furnace refractory management system involves a comprehensive audit and monitoring program which has been successfully applied to several copper flash smelting furnaces over the past 15 years. The fitness for service assessment provides a methodology to estimate the remaining life of the steel components by evaluating the existing damage and future damage rate based on the historical survey data. The above practices can provide the operator with cost savings by extending the vessel campaign life in lieu of implementing more rigorous refractory lining and shell audits. INTRODUCTION Primary copper smelting is generally divided into two categories of flash smelting and open bath smelting. There are many different types of vessels that can be used to convert the copper concentrate to blister copper including, flash, Mitsubishi process, TSL (ISA/Ausmelt), SKS Bottom Blowing, Anode and Teniente/Noranda furnaces, reactors, and Peirce Smith converters. Each vessel has its own complex and intense environment which requires careful refractory and steel design to withstand the severe thermomechanical and thermochemical attacks within its campaign life. The campaign life of furnaces is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper assessment of the existing conditions and safe remaining life of the vessels and/or refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a fitness-for- service assessment methodology to estimate the remaining campaign life of copper making furnaces resulting in cost savings and enhanced safety of the operating vessels.

Jan 1, 2019

By G. Sedelnikova, D. Kim, N. Ibragimova

"The object of this study was three samples of sulfide old tailings, which were obtained after Cu- Zn ores processing. Fine metal dissemination in sulfides as well as fine mineral intergrowth determine the refractory nature of material and low metal extraction using simple methods: gravitation 1-6%, flotation 32-48%, cyanidation 10-37%, and cause the need to use sulfide bio-oxidation to liberate gold and to recover it by heap leaching. The gold is the main valuable metal in the tailings with content 1-1.5 g/t. Heap bio-oxidation with mesophilic and moderately thermophilic bacteria was used for pre-treatment of tailings before gold heap leaching from bio-oxidation solid residues. The tailings have a low permeability < 0.3-1.2 m/day, which is caused by migration of fine particles, decreases recovery rates, and is poorly suited to heap bacterial leaching. Therefore, preliminary gold sulfide tailings with permeability < 0.3 m/day were pelletized using copper containing flotation tailings of converter slags and calcium oxide. The most gold extraction was obtained for pelletized tailings. The base metals (copper and zinc) were precipitated from bacterial solutions. Experiments have demonstrated effective bio-oxidation of all third gold sulfide tailings samples and enough high gold extraction 60-82%.INTRODUCTIONIn Russia, as everywhere, there is a trend toward deterioration in the quality of mineral resources, including non-ferrous and precious metals, manifested in lower grade and higher complexity of ores. The proportion of refractory ores is increasing, characterized by fine dissemination of metals in sulfides, intergrowth, and poor liberation of minerals during concentration, resulting in loss of base and precious metals to flotation tailings.Over the operation period, huge reserves (hundreds of million tons) of ore processing waste have been accumulated at mining and concentration operations. Because of the imperfections of the previously used ore concentration technologies, the content of precious and base metals in flotation tailings is comparable with the grades of the ores being currently processed. Therefore, old tailings can be viewed as an additional reserve of non-ferrous and precious metals. The works (DEN, 1997; Lyman, Johnson, & Guerney, 2000) demonstrate that, tailings containing sulfides (sulfur, copper, zinc, and other metals) are a potential environmental hazard since they produce acid drainage water containing toxic components. Processing those tailings would require designing an effective technology for recovering useful components and protecting the environment."

Jan 1, 2016

By R. E. Whitehead

"The earliest gold-mining operations in Ontario included the Cordova, Deloro, and Sophia mines north of Lake Ontario (see for example, Miller and Knight, 1914). The Cordova deposit, worked intermittently between 1891 and 1940, is reported to have yielded 22 774 oz of gold from 127 670 tons of ore averaging 0.19 oz/ton Au (Gordon et al., 1979). The property remained inactive for many years. In 1988, Gunnar Gold Inc. and Mill City Gold Inc. conducted a drilling program along the main Cordova vein. The present study is based on core from three drill holes through the Cordova gabbro (Fig. 1) and the carbonate alteration zones enveloping the quartz-carbonate veins. The relatively narrow width of the alteration zone and the availability of continuous sections of core provided an opportunity to conduct a compact mineralogical-chemical study of carbonate alteration and its effect on the redistribution of rare earth elements (REEs). Although the Cordova deposit is not of great economic importance, this study has revealed a number of interesting features which are interpreted as resulting from processes that may be applicable to gold-bearing quartz vein deposits elsewhere.The Cordova gabbro is layered in places, varying from fine-to coarse-grained and in color from light gray (feldspathic) to dark gray-green (amphibolitic). However, layering within the section of the gabbro considered here and which hosts the Cordova gold deposit is mainly textural rather than compositional. Samples of unaltered gabbro selected for analyses were medium- to coarse-grained; amphibolitic and anorthositic phases were avoided as being less representative of the general chemical composition of the gabbro.The Cordova intrusion has undergone regional metamorphism and consists dominantly of actinolite and saussuritized plagioclase with smaller amounts of granular clinozoisite and flaky chlorite; minor quartz, ilmenite, titanite, apatite, and calcite are typically present. Some actinolite grains have irregular rims of pleochroic green hornblende that is optically continuous with the actinolite. Both chlorite and clinozoisite occur in two modes. Chlorite occurs as an alteration product of actinolite and as separate grains in the groundmass. Clinozoisite and albite occur together as regional metamorphic alteration products of original plagioclase crystals and as discrete grains in the matrix.The main gold-bearing quartz-carbonate occurrence occupies an easterly trending, steeply southward-dipping carbonatized shear zone up to 15 m wide and 700 m long. The gold occurs principally in irregular lenses and veins of quartz-carbonate up to a foot thick occupying the lower part of the schistose shear zone within the gabbro. This zone consists of chlorite, biotite, and carbonate and is flanked on both sides by chlorite-carbonate schist lacking biotite. The chlorite-carbonate schist in turn grades into regionally metamorphosed actinolite-bearing undeformed gabbro.The dominant sulfide within the quartz-carbonate lenses and in the surrounding schist is pyrite which occurs mainly as small cubes (1 mm to 2 mm) generally making up less than 10% of the rock. Rare blebs of chalcopyrite are present. Magnetite is common throughout the schist."

Jan 1, 2001

By C. -K. Fang, T. H. Chuang

"Temperature effects on the erosion of the 6063 aluminum alloy were investigated. Erosion experiments were performed by sandblasting silicon carbide particles of 80 grit size. The target volume loss, and worn depths of the eroded material were investigated at different temperatures. It was found that the temperature had only a minor impact on the peak attack angle. The effect of temperature on erosion damage depended on the relative humidity (RH) of the environment. IntroductionThe synergy of wind and sand or dust may result in the erosion of materials. However, the severity of erosion damage in different areas and in different seasons might be varied, depending on environmental variables such as temperature and humidity. As a result, determining the effect of environmental variables on erosion damage is important in selecting or ranking materials for their suitable applications in diverse areas.The relationship between erosion wastage and temperature is governed by many factors including temperature dependent properties of the material (strength, ductility, toughness, and dynamic hardness, etc.), mechanical erosion characteristics, the rate of oxidation, and the mechanical properties of oxides. Although the effect of temperature on erosion has been studied for engineering materials (Smeltzer et al., 1970; Gat and Tabakoff, 1978; 1980; Levy et al., 1986; Levy and Man, 1986; Chinnadurai and Bahadur, 1995; Howard and Ball, 1997; Colclough and Yeomans, 1997; Suckling and Allen, 1997), published literature dealing with aluminum alloy is rather limited."

Jan 1, 2000

By C. M. Campbell

In his report on the Coal Resources of Southern Vancouver Island, Mr. J. D. MacKenzie stated that: "For various reasons it has been imagined that the coal deposits of Vancouver Island are extremely large and readily available." "Unfortunately," he added, "neither of these assumptions is correct." The chief disability under which the Island mines now labor does not concern the extent of the deposits. There is ample coal for the present demand. It does, however, concern the availability of the coal. If it were readily available the fuel-oil competition would not be serious and there would be no competition with Alberta, American, Welsh, or Australian coal along the Pacific Coast, for Vancouver Island coal could be produced at a price that would cut out all competition. The outstanding operating difficulty common to all Island mines is the extreme irregularity of the coal seams. To most people a coal seam is synonymous with uniformity, and in most coal seams a condition found at one point will be repeated at other points in the same seam throughout the basin. The accompanying drawings show how very far this is from being true in the Cassidy mine, which, in many respects, is typical of Vancouver Island mines. Figure I is a plan covering about 160 acres of the Douglas seam, the only workable seam in this part of the district. The area shown represents what has been the best producing part of the mine and indicates the very large percentage of the seam where the coal is either entirely lacking or so small in amount that it cannot be profitably recovered.

Jan 1, 1924

By A. J. Antony Chettupuzha

During a construction project, it is important to ensure that accurate and pertinent knowledge is delivered on time to appropriate personnel. The criticality of documents exchanged or referred to by various parties, evolves over the course of the project lifecycle. Determining the criticality of documents at different stages of the project can aid companies with managing the flow of information in an organized manner, while providing for the detection of potentially disruptive, erroneous material that could result in delays and costs. Therefore, it is crucial to determine documents which have the potential to disrupt a process (by virtue of being incorrect versions etc.) so that they may be isolated or prevented from entering or interfering with the active flow of information in a project, while also ensuring standard revisions of documents are recognized and accessed accordingly. Electronic Product and Process Management [EPPM] systems provide the capability to establish and map information flow between different parties in a construction project. Analyzing an EPPM system may yield information about the criticality of certain documents within an activity, as well as isolate characteristics peculiar to documents which can assist in risk mitigation. We propose methodology that identifies such critical documents.

Aug 1, 2013

By Barbara Kirby

Mining Industry HR Challenges Mining industry needs to hire approx. 100,000 workers by 2020 Attraction and retention of talent in all occupations Mobility of skilled workers between mine sites 70 percent of employers expect labour shortages over the next 5 years. Largest shortages: -physical sciences and engineering occupations -trades and ?undesignated? occupations ?Undesignated? Occupations ?Undesignated? Occupations -eg. mill operators, production / development miners and heavy equipment operators More than 20,000 workers will be needed by 2020 in the undesignated occupations and another 11,500 tradespersons Turnover rate for trades and undesignated occupations at mines is high: 8.3% compared to 5.6 % for all other occupations There is no system to recognize the skills of high-demand undesignated occupations

May 1, 2010

By A. Fakhimi

The effect of porosity on mechanical behavior of rock has been studied in the past using both experimental and numerical techniques. One important aspect of this study that has not received much attention is the role of void size and distribution on the mechanical behavior of rock. In this study, the CA2 computer program that is a hybrid discrete-finite element program for two-dimensional simulation of geomaterials is used. Numerical specimens with different macro-void sizes are loaded uniaxially. The Young?s modulus, Poisson?s ratio, uniaxial strength and crack initiation stress are studied. The numerical results are compared with the database of experimental tests on Plaster of Paris specimens containing Styrofoam spheres with different void sizes and porosities. It is shown that the macro void spatial distribution is partly responsible for the scatter of the experimental data. It is also shown that not-only the porosity but also the pore size can affect the deformability, crack initiation stress and rock strength.

May 1, 2009

By J. Shahabpour

"Breccias with angular and rounded clasts of a late-mineralization, ""barren"" hornblende porphyry dike set within a comminuted matrix consisting of rock fragments and quartz, cemented by quartz and K-feldspar of hydrothermal origin is observed in diamond drill cores from the Sar Cheshmeh porphyry copper deposit. Studies of age relationship between vein types, phyllic-altered clasts and the breccia groundmass suggest that the brecciation is a late event. The breccia clasts record evidence of hydrothermal reaction between the clasts and fluids responsible for the brecciation.Formation of bornite, in the breccia clasts of the originally barren hornblende porphyry dike, and in the breccia matrix, along with the scarcity of bornite in the Sar Cheshmeh deposit itself suggest involvement of fluids which are later and of different composition from the fluids responsible for the known mineralization at Sar Cheshmeh. These later fluids may be related to a later plutonic event and suggest the possibility of a later, and concealed deposit."

Jan 1, 1994