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By Edward Rybinski

Compañía Minera Antamina is a polymetallic mining complex that produces copper and zinc concentrates as primary products and molybdenum and lead/bismuth/silver concentrates as by-products. In 2007, Metso Process Technology and Innovation (PTI) was contracted to increase SAG mill throughput by integrating and optimising blast fragmentation, crushing and grinding for the harder M4/M4A (CuZn) ores. Following the implementation of recommendations provided by Metso PTI, the SAG mill throughput increased from 2750tph to reach an average of 3600tph for the remainder of 2007. Due to continued application of mine to mill integration and optimisation philosophy, by 2010, the concentrator consistently exceeded the target of 4400tph while processing harder CuZn ores.

Jan 1, 2012

By Jamie N. Burdeski, Susan E. Hartfield-Wünsch

Aluminum sheet use has been steadily increasing in the automotive industry to achieve mass reduction and improve fuel economy. One significant manufacturing challenge for aluminum sheet implementation is the reduced formability compared to the steel alloys it replaces. This paper includes friction results from the draw bead simulator (DBS), twist compression (TCT) and strip draw (SDT) tests, for two oil based lubricants and four hot melt lubricants. Formability testing was done with the same lubricants and materials, testing in pure stretch with a hemispherical punch, and in draw with a breadpan shaped die.

Jan 1, 2015

The theory and practice of sampling of particulate material have been the focus of a continued attention on the part of the mining industry worldwide for almost a century now, because of its critical importance at all phases of a mining project, from exploration (bulk sampling, assaying) to production (grade control) and marketing (quality control). A powerful, complete theory was put together by P. Oy (1968 to i982), but its applications to gold ores have met with limited success to date, due to the inadequacy of its sampling variance and minimum sample mass determination formulae to the challenging case of gold ores. This paper presents a research project completed at Inco Exploration and Technical Services Inc., using a geostatistical approach, to shed light on the results of P.Gy's theory, and adapt them to the case of particulate gold ores. After a reminder of Gy's formulae and a simplified demonstration of the generic form of Gy's and more traditional formulae, an empirical approach, based on sampling experiments from four gold deposits, shows how Gy's formulae must be corrected to adjust to the case of gold ores. The generality of the results formula is then substantiated with a geostatistical analysis of the problem. A parameterized formula results, and indications are given on how to fit its parameters to experimental data. Application guidelines and charts to fit any case and budget are presented, along with a detailed practical example.

Jan 1, 1991

By Atsushi Sainoki

Blast vibration induced by mining activities, such as stope production blasts, could lead to the initiation of seismic events that inflict damage to mine openings. In this paper, the effect of stope production blasts on nearby fault is examined. First, validation of blast vibration attenuation is performed with a numerical model representing a single blast hole through comparison with that calculated from charge-weight scaling law derived from in-situ data. Subsequently, a mine-wide scale model with a fault parallel to a steeply dipping, tabular ore deposit that is mined out with sublevel stoping method is generated, and the stopes are extracted and backfilled with static analysis to simulate burst-prone conditions on the fault. Based on the stress states, dynamic analysis is performed, in which blast vibration is applied to grid points on a stope wall on the hanging wall side. This assumes 9 blast holes located close to the wall, and blast-induced particle velocities that consider the positional relationships between the assumed blast holes and the stope wall are applied. During the dynamic analysis, blast sequence is considered, and stress states and shear displacement on the faults are examined. It is found from results that, after a rise in normal stress on the fault due to compressive waves induced by the blasts, the normal stress decreases because of the reflection of the compressive waves on the fault. The reduction in the normal stress due to the reflected waves is found to be large enough to cause the fault to slip. The results also show that the level of normal stress eventually keeps decreasing with time as the blast sequence proceeds and that an increase in shear displacement on the fault is accompanied by a decrease in normal stress. This study clarifies the mechanism by which blast vibration causes the fault to slip. In addition, the simulation technique to apply blast vibration that takes into account blast sequence and the locations of blast holes to a stope wall is developed.

Aug 1, 2013

By M. Kim, M. Ha

"The effect of red mud on the melting behavior of ferronickel slag was investigated by a laboratory-scale horizontal tube furnace. Melting and softening of slag samples fluxed with different amount of red mud was examined by in-situ visualization technique at temperature range from 1400 to 1550°C. FactSageTM 7.0 was used for the thermodynamic calculation of multi component system of ferronickel slag and red mud. Liquid phase area was extended to lower temperature by adding red mud indicating its suitability as a flux material. X-ray diffraction analysis confirmed the dependency of the phase changes on the red mud content. Microscopic observation by scanning electron microscope (SEM / EDX) clarified the phase transformations from olivine to spinel along with red mud additions.INTRODUCTION Ferronickel smelting by submerged arc furnace (SAF) is an energy intensive process performed at high temperature range 1500–1600°C. During the smelting process of saprolitic nickel laterite ore with a nickel content of 2.2–2.3 pct, a large quantity of ferronickel slag is being produced that account for 97 pct of ore charged. To achieve ferronickel grade of 15–20 pct Ni, electrical energy of 80 to 85 MW is used for the melting and reduction of nickel oxide (NiO) and iron oxide (FeO) in the ore (Rodd et al., 2010). Unreduced components, mostly MgO, SiO2 and partly FeO are removed from the furnace in a liquid slag form by a tapping operation. Due to the high melting temperature, forsterite (Mg2SiO4) based slag containing approximately 10 pct FeO requires typical process temperature of 1600°C. Flux in metallurgical process is a medium that decreases melting and operating temperatures while it increases fluidity of the liquid slags. Calcite and fluorite are examples of flux materials used for the ironmaking, steel refining and continuous casting process. Oxide systems based on CaO - CaF2 - SiO2 - Al2O3 - MgO cover most of the slag composition in ferrous metallurgy accordingly. Crucial operating factors for ironmaking and steelmaking slags are basicity (typically CaO/SiO2 ratio), viscosity and impurity levels. These are extensively controlled by the fluxes. General metallurgical fluxes such as limestone, dolomite and calcium fluoride are abundant in nature and supplied to steel mills at low prices. Meanwhile, in copper flash smelting process, silica is supplied with copper concentrate to remove iron oxide (FeO) generated from sulfide oxidation. FeO - SiO2 binary system formulates eutectic area at 25–38 pct of silica that has low melting temperature below 1205°C. Fayalitic system (Fe2SiO4) that has low viscosity (0.1 Pa·s) (Park et al., 2011) facilitates easy separation of slags from molten sulfide mattes. Recently, copper plants actively utilize recycled raw materials as a flux. Various recycled glasses are ground and fed to copper smelting process as a partial replacement of silica ore. Applying industrial wastes to smelting processes is advantageous since the operators can reduce the production cost remarkably. Not to mention the consumption of recycled materials can ultimately minimize the environmental risks and the waste management costs. The authors, therefore, investigated the reasonable waste materials that can be effectively used for ferronickel smelting process. Prerequisites for potential fluxing materials are non-recyclable property, low transportation cost and excellent performance as a flux."

Jan 1, 2017

By D. Harrington

Ventilation of underground workings consists in establishment of such control of air currents that the underground workers may work in safety, with maximum comfort and efficiency, and without impairment of health; and requires that the mine openings may be made subject to such control of air flow as to remove from these workings at ordinary times harmful gases and dusts, and that, at time of emergency, such as fire or explosion, there may be maintained as much or as little air flow as may be desired covering portions of the mine or the mine in its entirety. Control of air flow is the keystone of any ventilating structure, and this very essential feature is obtainable only by the installation of mechanically-operated fans, together with other;. ventilating devices such as doors, over-casts, regulators, etc. Every mine, large or small, coal or metal, should from the outset be equipped with a fan. While much has been written about natural ventilation and many claims made that in specific mines there is sufficient natural air flow, there are few if any mines, coal or metal, where natural ventilation supplies anything like adequately safe or healthful conditions for underground workers even at ordinary times; and at a time of mine fire or explosion, mines depending upon natural ventilation are practically helpless, and certainly are decidedly dangerous to those unfortunates forced to be in them. While ventilation has practically always been deemed an integral part of coal mining, metal mines have rarely paid much, if any, attention to air circulation until forced to do so by occurrence of some untoward condition or accident. Yet metal mines actually have as great need of efficient circulation of air as have coal mines. The coal mine must remove the dangerous explosive gas, methane, also fumes from explosives and, in occasional places, other gases such as carbon dioxide or nitrogen.

Jan 1, 1933

By Timothy W. Ellis, Abbas H. Mirza, R. David Prengaman

Recycled lead, i.e. material produced by the recycling of lead-acid batteries, has become the primary source of lead in much of the world. This has been important to the recycled lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses. Presently, battery manufacturing accounts for greater than 85% of lead consumption worldwide while recycled lead accounts for approximately the same market share of lead supply. Battery manufacturing and production of recycled lead are intimately coupled. In 2007, of all the industrial base metals, lead from lead-acid batteries had the highest recycling rate in North America at greater than 95%. In this paper we will review some of the processes and technologies used in a modern lead acid battery recycling facility, and how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industry requirements. We will also briefly review an advanced air emissions treatment system in a modern lead recycling plant that demonstrates the feasibility of a new maximum available control technology (MACT) for secondary lead smelters.

Jan 1, 2011

By Ibrahim Ocak

The prediction of machine utilization time and determining machine performance plays an important role in scheduling and planning tunnel excavation and data base created serve a major role in further applications. In this study, the construction methods of two twin tunnels situated between Basak Konutlari station and Istoc station are summarized. Geology in the study area is composed of fill and weak rock, respectively starting from the surface. The tunnels of 5.6 km in length were excavated with two different earth pressure balance machines (EPBM). Excavation diameters of the EPBMs were 6.564 m. The performance of the machines are analyzed and compared in order to accumulate data for further applications in similar ground conditions in Istanbul. The distance between two twin tunnels is 14 m from center to center and the EPBM in the one tube was almost about 100 m behind the other tube. Segmental lining with 1.4 m of length and 30 centimeters of thickness were used as final support. The overall performances of the two Lovat TBMs are found to be respectively as; the best daily advance rates 30.8 m/day and 30.8 m/day, the best weakly advance rates 115.0 m/day and 153.9 m/day, the best monthly advance rates 388.7 m/day and 400.5 m/day. Total waiting and maintenance times were 25.2 and 16.7 %, respectively.

Aug 1, 2013

By A. M. Ramadan

The composition of phosphate rocks, mainly used in manufacturing fertilizers, varies among deposits; therefore, phosphate rocks from different sources are expected to behave differently in acidulation processes. This paper examines the effect of preconcentration of phosphate ore from El-Sebaiya East, Egypt, using flotation on uranium leaching. A high-grade ore sample (27.3% P2O5, 168 mg/kg U) supplied by the Al-Nasr Mining Company, was subjected to reverse single-stage flotation to separate carbonate from the phosphate sample. Subsequently, P2O5 and U concentrations were 32.2% (92.1% recovery) and 225 mg/kg, respectively. After the leach process, the U concentration in the liquor was 319 mg/L.

Jan 1, 2014

By C. Allen

In 2004, Boliden Odda underwent an extensive modernisation project targeting mainly the leaching section of the plant. Direct leach technology was introduced as part of this project. The Direct Leach process, developed by Outokumpu, is an atmospheric oxidative leach of zinc sulphide concentrate. The effects of this new processing operation on behaviour of iron in the plant are discussed. As well, the filterability of the new residue on belt filters prior to its deposition in mountain caverns is also discussed. The solids from the direct leach process have been analysed by scanning electron microscopy, and the results of these analyses are presented.

Jan 1, 2006

By A. Anderko, V. G. Papangelakis, G. Moldoveanu, G. Azimi, M. Carlos

"OLI Analyzer is a software package that uses the powerful Mixed Solvent Electrolyte (MSE) model to simulate the behavior of multicomponent electrolyte solutions from infinite dilution to the limit of fused salt, and from temperatures below the freezing point up to near critical temperature of the mixture. The software also allows the creation of thermodynamic parameters for new chemical systems unavailable yet in public-domain or commercial software databanks. This communication reviews the basics of the model and provides some examples of modeling hydrometallurgical applications with emphasis on high temperature applications, including calcium sulfate scale formation in autoclaves, high temperature pH inference and iron control. INTRODUCTIONModeling of electrolyte systems has been of particular interest to various industrial processes, such as separation processes (e.g., solution crystallization, extractive distillation, seawater desalination or bio-separations), environmental applications (e.g., gas treatment, wastewater treatment or chemical waste disposal) and hydrometallurgy (e.g., pH control and neutralization, iron control, scaling and fouling of equipment). Using a chemical model, time-effective predictions of various properties of electrolytes can be obtained, which is beneficial not only during process monitoring, but also during process optimization and process scale up. As a result, pilot scale studies can sometimes be eliminated where budgetary constraints exist. Development of such a powerful model requires the use of a speciation-based model, in which solution chemistry is explicitly addressed (as compared with some models that treat electrolytes either as undissociated or fully dissociated systems), despite being computationally challenging. In addition, as a feature of electrolyte systems, speciation equilibria inherently influence the phase equilibria due to complex formation, ion pairing, and acid-base reactions. Therefore, how the electrolyte solutions behave at various conditions may differ significantly due to the non-ideality, which must be carefully addressed to obtain a model that is applicable to a wide range of conditions such as concentration, temperature, pressure and solvent system."

Jan 1, 2012

By Paul Toor

The operation of SAG mills is variable over time due to their continually changing liner shape, mass and subsequent load motion. However, this tends to be poorly accommodated in liner design and mill control, with only limited compensation made for this influence, usually in the first few weeks after a new liner is installed. With ever-increasing ore competency, increasing energy costs and decreasing ore grades, simplified design and operational approaches that compromise the achievable mill efficiency are no longer adequate. This paper presents a methodology that has been developed to measure and account for the changes in mill performance as the liner wears. This involves monitoring all liner profiles ? in other words the three-dimensional liner shape - over the life of the liner, then conducting controlled surveys at different stages of the liner wear life, and correlating the mill performance to the liner profiles. The measured liner mass is modelled to provide an ongoing meaningful load mass measure that excludes the liner mass.

Jan 1, 2012

By Colin Harvey

The paper industry in the Pacific Northwest is a potentially large market for industrial clays. Current trends within the paper industry towards higher quality newsprint, filled and coated papers, offers an incentive for exploration in the region since the current supply of kaolin is mainly from Georgia in the southeastern U.S. Freight rates commonly exceed US$100 per tonne. The kaolin resources of the Pacific Northwest require expensive processing technologies to meet the industry specifications and it is doubtful that any large development of the local resources can be supported at the present time. Competition from high-quality regional resources of carbonates is another factor weighing against the development of local kaolin resources while there is a potential threat from shipments ofAsian and Brazilian kaolin in the early part of the 21st century.

Jan 1, 2001

By John F. Haberer

DURING the twentieth century Canadians have been steadily improving their standard of living. Originally, this improvement depended almost entirely upon the export of basic raw materials and a triangular system of trade with Great Britain and the United States. However, since the Second World War, Canadian living standards have improved still further because of the very rapid d0evelopment of secondary industries. As a result of this development, the present demand for scientists and engineers exceeds the supply, and interest in scientific research has never been greater. It is the purpose of this paper to discuss the professional and economic status of Canadian scientists and engineers over the past half century. GROWTH OF RESEARCH It is difficult to determine accurately the amount of scientific research conducted in Canada since 1900. However, ?prior to World War I, it was limited and was connected mainly with primary industries and health. Government departments did some; university science faculties, overloaded with teaching responsibilities, did a little; and industry, which consisted mainly of subsidiaries of American and British firms, depended chiefy upon foreign sources for new information.

Jan 1, 1956

By P. J. Le Roux

"Mining worldwide and definitely in South Africa, is constantly under pressure to reduce its cost structure so as to sustain profitability. In underground gold mines where an open stope mining method is employed, dilution often has a significant effect on the viability of sustaining profits. Target Mine practices Open Stope mining Method and it was found that in some open stopes dilution was in excess of 10%, which has a significant impact on the sustainability of the mine.Dilution in excess of 10% can result in the reduction of the recovered grade from 5,5 to 4,5 grams per ton (g/t). The reduction of 1 g/t in recovered grade results in a potential loss of about ZAR21 Million per month bases on a gold price of ZAR240 000 per kilogram. Based on Life of Mine projections the potential loss of income could be as much as ZAR3,3 Billion. A reduction in dilution would have the opposite effect. There are a number of factors which affect dilution of which falls of ground in open stopes is a major contributor. The falls of ground can be attributed to a number of factors such as beam failure as a result of a larger than normal expected roof area (hydraulic radius too large), poor ground conditions, and poor blasting. The cost of damage to or loss of trackless equipment as a direct result of the falls of ground in open stopes, is very significant. The review of financial figures has indicated that this could be as high as ZAR491 million. This combined with the added cost of transport, hoisting, secondary blasting, milling and plant treatment costs of ZAR293 results in an estimated opportunity loss of ZAR784 million.Currently there is a significant amount of data available in the mining industry which could be effectively used to develop suitable back analysis techniques but to date this has not been used effectively. If dilution can have such an impact on current and future mining ventures then the optimization of back analyses for the prediction of dilution in open stoping could assist significantly in the reduction of dilution in massive open stopes. Rockmass classifications, geotechnical information, blast techniques, blast design, the stress strain environment and hydraulic radius all have an effect on, or play a role in the evaluation of dilution. Each of these factors will be taken into consideration to ultimately determine a measurable or calculated percentage of dilution in massive open stopes.The amount of overbreak in an open stope can be determined by subtracting the planned stope volume in m3 from the actual measured final stope volume in m3, which is obtained from the CMS (cavity monitoring system). This is in turn divided by the planned stope volume in m3 to determine the percentage overbreak. The CMS wireframe is imported into the geological model and its grade re-evaluated. From this the actual percentage dilution for this open stope can be determined. The dilution obtained can result in a major reduction of recovered grade for the open stope, but can also increase the recovered grade. The latter is normally the exception rather than the rule.When analysing data from Target mine the following was achieved:• Using 11 years of data a method of measuring and predicting the percentage dilution in open stoping was developed. This took into account rock mass quality, stress-strain state, and the hangingwall hydraulic radius (size of stope hangingwall exposed).• Implementation of this prediction method resulted in a reduction in falls of ground in open stopes. The benefit of this was a reduction in the damage to mechanised equipment resulting from less falls of ground which had a positive effect on the profit margins of the mine. As a direct result the recovered grade from the open stopes increased due to the reduction in the amount of dilution.• A design criterion, Dilution Stress-Strain Index (DSSI), was developed which allows the user to calculate, with certainty, the stability of the open stope and determine if m"

Jan 1, 2015

By E. W. Garner

THE greatest problem confronting business managers in modern times is not production, but distribution. It would be easy to expand productive output, but it is difficult to find markets for all that is produced. The fundamental source of economic difficulty, in the view of many observers, is a lack of proper balance between productive capacity and consumptive capacity. The studies conducted by the Brookings Institution on the general subject, "The Distribution of Income in Relation to Economic Progress", have led to conclusions of far-reaching significance, which may be summarized briefly as follows: (1) We have never lived beyond our economic means or capacity. (2) We have not been suffering from general overproduction. (3) We have not as yet reached a stage in our economic evolution at which it is possible to provide adequate standards of living for everybody. ( 4) It would require less than a 25 per cent increase in purchasing power among the masses to absorb our full productive capacity. (5) Production-curtailment programmes-whatever their merit in meeting temporary maladjustments-can only lead to national impoverishment. (6) Our inability to find markets adequate to absorb the full output of our productive establishments is explained by the unequal distribution of income and consequent restricted flow of purchasing power through consumptive channels. (7) The slow rate of growth of consumptive demand serves to retard the rate at which new capital is constructed, and hence the rate of economic progress. (8) The primary need is a rapidly expanding total income, and a broader diffusion of this income among the masses of the people. (9) A broader diffusion of income can best be achieved by reducing prices as rapidly as increasing efficiency will permit. That is to say, the benefits of technological progress, mass production, and low unit costs must be promptly passed on to consumers in the form of lower prices-giving more for each dollar.

Jan 1, 1936

In this study, we develop a detailed model of the likely future carbon footprint of primary copper supply. We develop a peak copper production model, based on a detailed copper resource data set, and combine this with a comprehensive life cycle assessment model of copper mining and milling to predict greenhouse gas emission rates and intensities of Australian and global copper production up to 2100. By establishing a quantitative prediction of both copper production and corresponding greenhouse gas emissions of Australian and global copper industry, we then analysed the emissions intensity of various energy input scenarios, such as business-as-usual, solar thermal electricity and solar thermal electricity with biodiesel. The Australian Government has an aspirational goal for long-term greenhouse gas emissions of an 80% reduction from the 2000 level by 2050. For the copper sector, this means moving from about 12.6 Mt CO2e in 2000 to a goal of some 2.52 Mt CO2e in 2050 (assuming equal emissions reductions across the economy). Based on the energy sources modelled, only the solar thermal plus biodiesel scenario was capable of achieving this goal at about 0.15 Mt CO2e, since the solar thermal alone scenario still includes normal petro-diesel as a major source of emissions. Overall, it is clear that there are abundant resources which can meet expected long-term copper demands, the critical issue is more the carbon (and environmental) footprint of different copper supplies and use rather than how much is available for mining. It is clear that the switch to renewable energy can have a profound impact on the carbon intensity of copper supply, even allowing for increased energy intensity as ore grades decline, and a complete conversion to renewable energy will position the copper sector to meet existing annual greenhouse gas emissions targets and goals.

Aug 1, 2013

By Z. Abbasloo, A. Masoomi, L. Ebrahimi, A. Mortazavi, A. Keshavarz

"Investigation and 3D analysis of Heap no. 2 of Meydook copper complex was the subject of this study. In this project all geological and geotechnical investigations conducted in the mine were evaluated aiming at determination of Heap no. 2 design parameters. The main objective of the project was to evaluate the potential for construction of Heap. No. 2 on a waste dump built in a valley in the north side of the pit.Considering the space limitation for dump location this was a viable alternative to reduce the costs associated with heap no. 2 construction. Moreover, it allowed for a significant reduction in overall mining costs. Considering the project condition, a 3D analysis of heap major structures including; valley rock foundation, waste dump, and low grade ore was carried out. Five sets of analyses were conducted and the displacement and stress fields were calculated within the heap no. 2 components. In all analyses conducted the subsident profile was determined for the valley base rock and heap foundation (waste dump). Moreover, the shear interaction between heap and waste dump was evaluated at the heap interface. The analyses results showed that the maximum settlement at the heap base is about 4-5 cm and the waste dump provides a safe and reliable base for heap construction. Moreover, the analysis results showed that the selected %5 grade for the heap interface is good and does not pose any risk in terms of heap Interface shear displacements. A sensitivity analysis of heap mechanical parameters was also conducted. The obtained results show that if the friction angle of heap material is reduced below 25 degree due to acid spraying process, the heap walls become unstable and the heap geometry must be redesigned."

Jan 1, 2015

By Gordon A. Gross

During the last half century major steel industries of the world have become dependent on iron and manganese resources derived from siliceous ironformation sediments. More than two billion years ago vast amounts of iron and manganese were deposited in ironformation sediments on all continents and until recent years their genesis was considered to be a uniquely Precambrian phenomenon. Research work has demonstrated that the origin of the banded ironformations was related to major tectonic features and associated volcanogenic processes that were active throughout geological history. Similar sedimentary-tectonic environments are being explored on the seafloor where metalliferous sediments are forming today. Ironformations are now considered to be a major part of the stratafer group of stratiform metalliferous deposits. They developed in sedimentary basins in areas where deep tectonic fracturing intersected high thermal gradients in the earth?s crust and gave rise to profuse volcanism and the hydrothermal effusive discharge of metals in the vicinity of the volcanic centres. Concepts for the genesis and metamorphism of stratafer deposits as revised in the last half century have had a profound impact in the development of iron ore resources and have had a dramatic impact in the use of metallogenetic concepts for guiding exploration for other mineral resources. They are based on the tectonic history and stratigraphy in the sedimentary basins, the role of hydrothermal volcanogenic processes , as well as environmental and sedimentation factors which influence the deposition of silica, iron , and other metals that were emphasized in the past. Topics of special interest in the genesis of ironformation and stratafer deposits and for guiding mineral exploration are: biomediation in their sedimentation and genesis, the significance of metamorphism in the processing and beneficiation of iron ore and in the genesis of iron ore by natural enrichment processes, syngenetic concentrations of Mn, Ti, Cu. Zn, Pb, Ni, Co, REE, F, Ba, B, As, Hg, W and Au in ironformations and stratafer lithofacies, and the mobilization of gold and other elements by alkaline solutions during diagenesis of ironformation and other stratafer metalliferous sediments.

May 1, 2003

By A. Allaire, J. Torrealba-Vargas, R. Welyhorsky

Early testwork was carried out to select the plant process design criteria and flowsheet selection. Additional testwork was carried out during the feasibility study to support the optimization of the plant design criteria. The test results showed that the recovery of gold was not very sensitive to grind size in the range of 75 to 105 microns. An additional result was that the presence of lead nitrate did not improve the kinetics of gold leaching. This conclusion was supported by the low content of sulphides in the ore. It was also found that the presence of lead nitrate increased copper dissolution, producing the potential for an increase of copper reporting to electrowinning, which is detrimental to the overall gold recovery process. The use of oxygen in leaching was investigated to increase leach kinetics. The results of leaching tests to compare using oxygen instead of air indicated that, due to the improved leach time, it was possible to reduce the number of leaching tanks from twenty four (24) to twenty (20).

Jan 1, 2011