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By J. Cayouette, . Blatter, P. Cousin

The Laronde mill was commissioned in 1988 and has been treating the Laronde Perim ore since 2000. The Laronde plant, situated in the Abitibi region of Quebec, has experienced mill expansions to accommodate 7500 mtpd and to recover gold and silver as well as important amounts of base metals (Cu, Zn, Pb). Ten sequential metallurgical and environmental processes are responsible for metals recovery and process viability. Over 200,000 ounces of gold, 4,5 million ounces of silver, 7000 tonnes of copper, and 78,000 tonnes of zinc are produced annually. In 2008, the Goldex plant began trucking high wade (35-45 Wt Au) pyrite sulphide concentrate (TCGO) for gold extraction at a newly constructed treatment plant, increasing gold output at Laronde by 40,000 ounces. In 2009, the high gold wade Lapa ore processing facilities were annexed to the Laronde plant increasing output by 120,000 ounces of gold. TCGO and Lapa productions are forecasted until 2018 and 2015 respectively, with known reserves of each mine. Today, up to 140 permanent employees run and optimise the Laronde plant operation. As a result, Laronde has intricacies intrinsic to a large and varied operation. The paper will outline the metallurgical highlights, challenges, and future outlook related to the treatment of each ore type (Laronde, TCGO, and Lapa)

Jan 1, 2011

By W. Lin, Z. Z. Dong, C. L. Zhou, Y. C. Kuang

The inversion of rock mechanical properties based on well-logging data is a common method to drillbit selection in petroleum engineering, the basic principle of which is to use deep-well logging data and experimental regression model to calculate rock mechanical properties. The profile of rock mechanical properties can be established. According to the profile, the type of drillbit can be selected in different formations, which will improve the economic benefit of bit use indicators. Compressive strength of rock is one of the most important parameters. Conventional method to establish regression models of acoustic velocity and uniaxial compressive strength is on the basis of rock core sonic experiments and uniaxial compressive experiments. However, with the increase of deep drilling operation, triaxial compressive strength prediction model will play a more vital role in drillbit optimization selection in deep wells and improving ROP (Rate of Penetration). Triaxial compressive strength is an important parameter to evaluate the formation strength property. In this paper, to the sandstone commonly encountered in oil drilling, combined the rock mechanical experimental results with the changing porosity experimental results under confining pressure, a new interpretation model of triaxial compressive strength based on well logging data is proposed. Firstly, three types of sandstone samples are collected. Then measured components, uniaxial compressive strength, triaxial compressive strength and porosity. Experimental results show that: confining pressure has a significant influence on sandstone strength, with the increase of confining pressure, triaxial compressive strength increase; furthermore, the triaxial compressive strength of different porosity sandstones have different change rules when confining pressures changes; sandstone porosity decreases with the increase of confining pressure and it obeys logarithmic function. According to the results, regression models of sandstone, in-situ uniaxial compressive strength model and uniaxial compressive strength model under normal pressure are generated. Meanwhile, using well logging data in the acoustic velocity, density and gamma value can derive in-situ rock formations uniaxial compressive strength and in-situ porosity. Eventually, a new model established in this paper, containing in porosity, uniaxial compressive strength, lateral pressure and power exponent of regression, can predict triaxial compressive strength which will guide drillbit selection.

Jan 1, 2015

By R. Kumar, A. K. Verma

"In this paper, an anisotropic shear behavior of rock joints is investigated under constant normal load condition (CNL). The natural rock joint roughness is transferred to artificial rock samples using room temperature vulcanizing (RTV) silicon rubber. Artificial cylindrical rock joint samples (90 mm diameter and 50 mm height) are made by mixture of cement, sand, and water in the ratio of 1:1.5:0.45 (by weight). Direct shear tests are conducted on these samples in twelve directions at 30º apart at four different normal stresses (250kPa, 500kPa, 1000kPa, and 1500kPa). Thus, 48 samples are tested in laboratory. Test results shows that the peak shear strength (?) of rock joints is anisotropic in nature due to change in morphological features in particular shearing direction. Joint roughness coefficient (JRC) is determined in each shearing direction by trial and error method using Barton’s model (1973). Further, cohesion ( c) and angle of friction ( ? )of joint surface in each direction is determined. Finally, a relationship between angle of friction ( ? ) and joint roughness coefficient (JRC) is developed. Experimental shear strength and Barton’s shear strength is compared and it is found that effect of anisotropic decreases with increasing normal stress. INTRODUCTIONRock mass is generally composed of discontinuity which refers collectively to joints, faults, bedding plane and folds etc. ISRM (1978) defined joint as a line of break of geological origin along which there is no visible displacement. Joint is three dimensional discontinuity which composed of two matched/mismatched surfaces. The presence of joints in rock mass plays an important role to define its overall shear strength, deformability behavior, in-situ stresses and hydro-geological properties. The shear strength of rock joints is important in the design of near surface/ deep geotechnical works (mining excavation, dam foundation, power plants, underground caverns, and slopes).In last 40 years, many constitutive models are developed to predict shear strength of rock joints under CNL conditions (Patton 1966; Landanyi and Archambault 1969; Barton 1973; Goodman 1976; Barton and Choubey 1977; Plesha 1987; Desai ad Fishman 1991; Amadei and Saeb 1992; Maksimovic 1992; Wibowo et al. 1993; Huang et al. 1993; Amadei et al. 1998; Indraratna 2000; Homand et al. 2001; Wang et. al. 2003; Samadhiya et. al. 2008; Asadollahi and Tonon 2010; Ghazvinian et al. 2012). These constitutive models have limitations to predict shear strength of rock joints in one direction. Till date, among all constitutive models, Barton (1973) model is widely used in practice due its simplicity. It includes parameters such as joint roughness and joint compressive strength (JCS) to quantify joint surfaces."

Jan 1, 2015

By Arthur M. Whiteside

Discussion of the laws bearing upon the economics of mining in this province at once resolves itself under three headings: (a) The rights and obligations of holders of mineral bearing lands; (b) Taxation of mines; (c) Regulation of methods adopted in financing mining operations. Titles: The law relating to titles is contained in the Mineral Act, Placer Mining Act and Coal Mines Prospecting Act. Origin: Mining laws in force in this province and elsewhere on the continent had their origin in the rule-of-thumb regulations adopted by prospectors themselves, when, far from the centres of civilization and the seats of the courts of justice, they found it necessary, for mutual protection, to fix the conditions of possession by right of location, and to prescribe the duties to be performed in order to enable the individual to maintain his ground against all comers. These regulations have been codified and added to by legislatures, until we find adequate protection and safeguard to property in the laws of this province.

Jan 1, 1924

By W. F. MacIsaac

"The large low-grade Copper Mountain deposit is located in the northern portion of the Gaspé Cooper Mines property. It is approximately 1 mile north of the Needle Mountain deposit. The orebody outlined to date lies in the top 1,000 feet of the Grande Greve formation. Chalcopyrite occurs in association with pyrite and quartz in small veinlets and numerous fractures. The deposit is immediately adjacent and parallel to a quartz-feldspar dyke and may be associated with a nearby porphyry stock. Stratigraphy, alteration and structure appear to have played an important role in ore deposition."

Jan 1, 1969

By Corby G. Anderson, Caelen D. Anderson, Patrick R. Taylor

"The United States contains a variety of domestic rare earth element mineral sources containing such as ancylite, bastnasite, monazite, and xenotime. Research has been performed to investigate the fundamental surface chemistry involved in the froth flotation of these minerals, and apply the knowledge gained to substantiate the results through experimental testwork on a domestically sourced rare earth ore. This paper will outline the fundamentals and literature of rare earth mineral flotation, review its industrial applications and provide some recent research updates.THE RARE EARTH ELEMENTSRare earth elements (REE’s) are a unique family of elements with nearly identical physical and chemical properties. They account for approximately 1/6th of all naturally occurring elements, but the entire group occupies only one position on the periodic table. These 15 elements make up the lanthanide series (atomic numbers 57–71), and all but one (promethium) occur naturally. In addition to these 15 elements, yttrium and scandium are also considered rare earths since they tend to occur in the same deposits as the rare earths and share similar physical and chemical properties as seen in Figure 1. In particular Figure 2 denotes, a cartoon of the subtle differences in each caused by the 4f atomic sub shell (Gschneidner Jr., 1964). These subtle differences result in very difficult challenges in the selective concentration and final separation of each rare earth. (Anderson, 2015, Kronholm, Anderson, Taylor, 2013)Rare earths are separated into two different subsections; the “lights” or LREE’s (lanthanum57 through europium63) and the “heavies” or HREE’s (gadolinium64 through lutetium71). Yttrium is generally considered a heavy rare earth since its ionic radius is close to that of the HREE’s, while scandium is not considered either a light or a heavy."

Jan 1, 2016

By C. A. D' Odorico

The zinc pressure leaching (ZPL) plant at Teck Cominco's Trail Operations was started up in 1981 and represented the world's first commercialization of the technology. From the outset, the process was designed to operate using iron-rich Sullivan Mine zinc concentrate. When the Sullivan Mine reached the end of its life in 2002, the ZPL plant underwent a significant process change with the treatment of 100% Red Dog zinc concentrate. Through careful improvements to existing plant processes, controlled changes to plant operating parameters and a rapid adjustment to the modified process by operations personnel, the plant has been successfully converted to processing a feed of 100% Red Dog zinc concentrate. This paper discusses the challenges faced during the conversion and describes the modifications to plant operating procedures, as well as changes to plant processes.

Jan 1, 2004

By F. Rivard, M. G. Drouet, W. S. Ruff, P. Carabin

"In both the hot rotary-salt-furnace (RSF) treatment of aluminum dross and the cold ball-millsieving (BMS) treatment of zinc dross, enormous amounts of energy and recoverable metal are wasted and large amounts of greenhouse gas are produced. Such wastes and the environment pollution could be avoided by using the DROSRITE PLUS™ technology. Economic and GHG production comparisons between the presently used industrial treatment processes and DROSRITE PLUS™, supported by over one hundred tests conducted in Canada, the US and Europe, are presented. The savings, with DROSRITE PLUS™, would be about $191 and $418 per MT of aluminum and zinc dross, respectively.INTRODUCTIONDross is a material, which forms on the surface of molten non-ferrous metal, such as aluminum or zinc, during melting, metal holding and handling operations when the molten metal is in contact with a reactive atmosphere. Dross normally consists of metal oxides entraining a considerable quantity of molten free (unreacted) metal, and for economic reasons it is desirable to extract the free metal before discarding the residue. In the case of aluminum dross, recovery of the metal is usually carried out by treating the dross in a furnace at a high temperature (Peterson et al., 2002). By contrast, cold zinc dross is crushed in a ball mill followed by sieving to separate the coarse metal portion from the fine oxide residue.The conventional aluminum dross treatment process, using gas or oil-heated rotary salt furnaces (RSF), is thermally inefficient and environmentally unacceptable because of the salt slag and CO2 produced from the combustion of fossil fuels. In the past several years, a number of salt-free processes have been developed and some of these have found limited commercial use (Gripenberg et al., 1994; Lavoie et al., 1990). In all these dross treatment processes, heating of the cold dross in a rotary furnace requires an external energy input that varies between 375 and 2,500 kWh per (metric) tonne of dross. Molten metal separated during processing of the heated dross is tapped, and the remaining solid residue is discharged from the furnace."

Jan 1, 2012

By D. Bernard

Over the last decades, the wrought aluminum casting industry has made significant progress with regards to process consistency by the introduction of new technologies in the field of liquid metal processing and casting. These technologies, combined with the application of best practices, have led to increases in productivity as well as better process performances and product quality. The competition in the addedvalue aluminum products (by opposition to P1020 production) is, however, very strong and involves players that did not hold a major role five years ago but who are now exerting a strong competitive pressure on our industry even sometimes from far abroad. There are still technical and technological challenges remaining in the different areas of aluminum casting production, amongst which metal pre-treatment, furnace operations, in-line treatment and casting hold a predominant influence. The comprehension of the contribution of each individual process step to the entire process chain is a key element and must be considered in future process optimisations. This paper presents the technological position of the casting industry and tries to highlight areas where further progress can be made.

Jan 1, 2006

By D. R. Murray

A four-year study was carried out to determine the ability of coniferous trees to aid in the reclamation of uranium tailings at Elliot Lake. Five species were planted: white cedar, white spruce, jack pine, scotch pine and red pine. More than 570 bare-root, two-year-old seedlings were planted on bare tailings and in areas of established grasses. A further division was made between areas of coarse and fine tailings. Over-all survival and growth of the trees has been far below expectations based on previous experience with several varieties of grasses. The criteria for assessment have been per cent survival and yearly growth as determined by plant height. Pine was superior, with 68% survival when planted in bare coarse tailings, 45% for vegetated coarse tailings and 34% for vegetated fine tailings. Cedar had the worst survival rates at 49%, 14% and 7% respectively. No species survived on bare fine tailings. The survival and growth of the coniferous trees have been related to species, environmental conditions and tailings properties.

Jan 1, 1978

By T. Bednarski, T. McCallum, L. Moya, L. Nsenga, B. Mbao

The accumulation of solids in solvent extraction (SX) circuits can cause problems with the physical and economic performance of the operation. These solids are responsible for the formation of crud, a solid stabilized emulsion containing organic, aqueous, air, and fine solid particles. The build-up of crud in SX settlers can limit SX operation throughput, require plant downtime, lead to higher organic losses, or result in higher aqueous in organic entrainment (all of which can have a significant, negative economic impact). Current practices for crud management are typically reactive. Crud is physically removed after it has been allowed to build to excessive levels in the circuit and processed mechanically using centrifuges or filtration. A new proactive solution has been developed to prevent crud formation and build-up. Low ppm dosage of an additive, ACORGA® CR60, into the pregnant leach solution (PLS) has resulted in reduced crud formation in pilot and commercial scale for a variety of PLS streams. This paper will review results from operations in North America and Africa, covering heap leach, concentrate leach, and agitated leach feeds. INTRODUCTION Crud formation and build-up in solvent extraction (SX) circuits has been a long time topic discussed and claimed to be crucial to the whole hydrometallurgical process (Liu, et al, 2006). Crud formation is present in all SX systems be it copper, uranium, zinc, etc., and Ritcey (1980) defined crud as a stabilized emulsion containing organic, aqueous, and fine solid particles. The ore type and feed composition is a major determining factor of crud formation and typically contains Si, Al, Fe, P, and sulfates (Ritcey, 1980). It typically builds at the interface between the organic and aqueous, but can also be observed as floating crud on the surface of the settler, or bottom crud, which is common to find in circuits treating agitated leach feeds such as in Africa. As crud formation has been unavoidable, many of the current crud management techniques are reactive, allowing crud to form and build in SX circuits. Once it does, it is removed and treated via different mechanical techniques, typically through some type of filtration or three-phase centrifuge, to remove the solids and recover the organic phase trapped within the emulsion (Ritcey, 1980). Automated pumping systems have also been designed and are frequently used in North American operations. The time and capital required to react to crud formation can be an overwhelming aspect to SX operation.

Jan 1, 2019

By J. Paquin, P. Doiron, G. Proulx, P. Champoux

After nine years on a 36 hour schedule and two programs of creeping, the Alcoa Deschambault Potroom of faced the necessity of changing its organization for many reasons: the anodes butts were too small, the anode schedule was unbalanced, the iron content in the metal trends had increased, the metal tapping volume did not convene with crucible capacity and the liquid measurement task was delayed by tapping activities. A kaizen activity inspired the Potroom department to improve the organization. A team of 15 people including the process engineer, the process technician, team supervisors and Potroom operators developed a scenario, which would permit flexibility to creep pots if energy is available and an increase of added value production.This paper will describe the systematic approach, the communication method, the trials, the changes, and our success, along with the problems experienced by the team during the adaptation of Alcoa Deschambault Potroom organization over a 20 month period. Aluminium 2006 45th Annual Conference of Metallurgists ofCIM Montreal, Quebec, Canada Edited by

Jan 1, 2006

THE Michipicoten area, one of numerous iron-bearing "Archean" segments in the Shield, contains two main types of iron formation, a normal Keewatin-type, consisting of interbanded chert, siliceous magnetite and jasper, and, gradational to this, a carbonate-sulphide type which contains large de-posits of siderite and pyrite. The carbonate-sulphide type of iron formation bears a direct and intimate relationship to the volcanic development of the area; it there-by affords some insight into genetic problems of Archeanron formation in general. The purpose of this pa-per is to summarize the geological setting of Michipicoten iron formations and to briefly review genetic aspects of recent work in the area. GENERAL GEOLOGY in largely by assorted volcanics and sediments of the Michipicoten series and younger, regional granite masses. (Fig. 1). The Michipicoten series comprises a thick assemblage of mixed flows and pyroclastics together with elastic sediments and banded iron formations. The volcanics belong to the Andesite-Rhyolite Association, and characters-

Jan 1, 1961

By Simon C. Dominy

"There are two main issues stemming from Vallée’s (2002) comments on Dominy et al. (2001b). First, he raises the importance of quality assurance/quality control (QA/QC) during resource estimation programs, and second, he indicates that the resolution and understanding of continuity (grade and geological) issues are paramount in the classification of resources. In particular, continuity is critical at the boundary between the Inferred and Indicated Mineral Resource categories. The original contribution agrees with the importance of these points, and the principal author offers the following discussion and clarification. Further comment is also provided on the reporting of grade uncertainty through grade ranges.It is worth remembering that vein-gold deposits (e.g., shear-zone, lode-gold, mesothermal types etc.), particularly those containing coarse gold particles (e.g., >100 µm), generally show large variations in grade and an erratic grade distribution. In most cases, diamond drilling is a good measure of geological continuity (depending on drill spacing), but a poor measure of grade and its distribution. High-nugget effect deposits rank among the most difficult deposit types in terms of producing an accurate and precise resource estimate, and clearly represent a distinct deposit type."

Jan 1, 2002

By V. Gaudreault

Rio Tinto Alcan (RTA) has three smelters that use the Alcoa P155 technology: two in Canada (Grande-Baie and Laterrière, Saguenay, QC) and one in the United States (Sebree, Kentucky). The oldest RTA P155 smelter was built in the 1970s (Sebree) and had an initial current intensity of 155 kA. In the 1990s, RTA installed an amperage booster in Grande-Baie smelter to increase cell productivity. Since then, RTA has continuously pushed the limit of this technology and the target amperage that was 195 kA in 2005 has been increased to 210 kA in 2010.This article describes the successful plant-scale trials to increase current intensity from 195 kA to 210 kA, and the key performance indicator results. It demonstrates RTA's technology leadership to undertake such a development with its Brownfield smelters.

Jan 1, 2011

By A. Giacomini, M. Nazem, E. Fathi Salmi

"Numerical simulation of collapse of tunnels in weak rocks is one of the challenging problems in rock mechanics. Collapse can impose technical and financial difficulties during the construction of underground excavations. This phenomenon, particularly in shallow excavations, may lead to propagation of a caved zone toward the surface and formation of chimney subsidence. Chimney subsidence has numerous catastrophic consequences such as the adverse environmental impacts and damage to surface structures in vicinity of excavations. Due to the importance of subsidence in civil engineering, the main goal of this study is to propose an appropriate method for preventing the formation of subsidence in shallow tunnels in weak rocks. The Dolaei road tunnel is investigated as a case study, where a large chimney subsidence has occurred. The geology of the area and the geostructural characteristics of the rock mass surrounding the tunnel are briefly reviewed in this paper. Two-dimensional as well as threedimensional numerical simulations are conducted to study the tunnel stability. Moreover, the effects of staged excavation and pre-supporting method on controlling the ground movements are studied. Outcomes of this study indicate that employing forepoling and staged excavation can be a practical remedy to control the ground movements and prevent the formation of chimney subsidence.INTRODUCTIONPredicting the formation of subsidence, mainly sinkhole subsidence over civil or mining excavations, is a very challenging task. An accurate prediction of subsidence is required for selecting an appropriate control and mitigation system to reduce the level of ground movements and its impact on the surface life (Bétournay et al. 1994; Leca and New 2007). Excavations, particularly in weak grounds, could result in surface subsidence; they modify the in-situ stress conditions as well as the hydrogeology of the area. Construction of unsupported excavations in soft soils and relatively weak rocks usually leads to the formation of a failure zone behind the face. In a very soft ground, the failure zone can extend towards the ground ahead of the tunnel face. Propagation of this zone toward the ground surface results in generation of sinkholes."

Jan 1, 2015

By Robert H. Clark

Introduction During the last twenty years, science and industry have been strenuously endeavouring to discover new sources and new kinds of liquid fuels and to work out suitable chemical methods for their production. One of the new possibilities for the production of liquid fuel on a large scale is law-temperature carbonization of various grades of coal. The use of alcohol as motor spirit, in spite of its relatively low calorific value, is being widely investigated. Its production by fermentation of sugars, its recovery from the sulphite liquors of the paper industry, its production directly from wood and also from calcium carbide, have all been considered. At present the most promising line of investigation would appear to be the further development of those technical processes which yield liquid fuels from coal; since science has shown the possibility of preparing all kinds of liquid fuels and even the complete conversion of coal into oils. The present paper will consider briefly: 1. The production of primary tar by low temperature carbonization of coal. 2. The hydrogenation of coal. 3. The synthetic processes of Dr. Franz Fischer.

Jan 1, 1928

By B. McKevitt, P. Abbasi

The ion exchange process (IX) is applied in the mining industry for the removal of impurities from process streams, treatment of waste solutions prior to disposal and the recovery of valuable metals. Extensive studies have been performed with the goal of modeling of IX for the case of a single metal loading onto iminodiacetic resin in the hydrogen form. However, in a real system, a resin may be saturated by impurities (iron, calcium, magnesium, manganese), which are then displaced by the metal of interest. The present study provides an insight into the Fe2+ loading process onto iminodiacetic ion exchange resin under the infinite solution volume condition. The study involves the measurement of iron loading under a variety of experimental conditions as well as an attempt to model the loading process using the hybrid correlation advanced by McKevitt (2012). The importance of the experimental and modeling work are discussed in the context of resin in pulp recovery of nickel.

Jan 1, 2014

The 14MW SAG mill at Tarkwa, Ghana, experienced a frozen drop charge incident on 10 February 2010. This caused downtime of 112 hours, a repair cost of $200k and production loss of 162,000 tons, corresponding to a loss of $8.9M. A new locked charge protection system was installed on the two Tarkwa mills on 30 July 2010, mitigating this risk. This system calculates the ore angle in real time while the mill is starting up and trips the mill if the ore angle exceeds a trip angle setting. The calculation of the ore angle is derived from the mill motor rotor currents only - no mechanical transducers are required. The head of Gold Fields West Africa, Peter Turner, says of the new system: "This is excellent work and the type of technology that has had and will continue to have, major opportunity cost impacts on our business."

Jan 1, 2012

By W. J. Wolfe

"THE DETECTION OF BURIED MINERAL DEPOSITS by chemical analysis of vegetation (biogeochemistry) or visual observation of plant cover type (geobotany) is based on fundamentally simple principles. The root systems of vegetation collect aqueous solutions from a large volume of moist ground below surface and act as efficient sampling mechanisms by providing a composite sample of a reasonably large area. These aqueous solutions constitute a source of ore-associated metals that may ultimately be concentrated in the upper parts of the plant. Although certain plant species have a limited ability to break down primary minerals and extract elements, biogeochemistry normally detects only metals capable of moving in solution. Metal concentrations in the underlying soil must therefore exist in a form that is immediately available for uptake by the root systems - generally in the ionic state in aqueous solution or in readily exchangeable form on the surfaces of soil clay minerals. As a result, biogeochemical responses are closely related to variables such as soil pH, Eh, exchange capacity and complexing agents that control metal mobility in the surface environment. In terms of cost, reliability and anomaly contrast, soil geochemistry will normally be more useful than biogeochemistry in locating buried mineralization in regions of residual overburden or thin transported cover. However, in areas where the root systems penetrate thick deposits of transported post-mineralization overburden, plants can provide an effective mechanism of sampling below the transported material. Biogeochemical research in Canada, Scandinavia and the U.S.S.R. has therefore focused on the potential use of plant prospecting methods (1) in areas where the upper horizons of podzolic soils do not provide an adequate response to anomalous conditions under thick deposits of glacially transported till and (2) in widespread regions of peat and muskeg terrain where near-surface mineral soils are absent."

Jan 1, 1971