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By R Castroviejo, E Pirard, L PTrez-Barnuevo

Process mineralogy provides the mineralogical information required by geometallurgists to address the inherent variation of geological data. The successful beneficiation of ores mostly depends on the ability of mineral processing to be efficiently adapted to the ore characteristics, liberation being one of the most relevant mineralogical parameters. The liberation characteristics of ores are intimately related to mineral texture. Therefore, the characterisation of liberation necessarily requires the identification and quantification of those textural features with a major bearing on mineral liberation. From this point of view, grain size, bonding between mineral grains and intergrowth types are considered the most influential textural attributes. While the quantification of grain size is a usual output of automated current technologies, information about grain boundaries and intergrowth types is usually descriptive and difficult to quantify to be included in the geometallurgical model.Aiming at the systematic and quantitative analysis of the intergrowth type within mineral particles, a new methodology based on digital image analysis has been developed. In this work, the ability of this methodology to achieve a more complete characterisation of liberation is explored by the analysis of chalcopyrite in the rougher concentrate of the Kansanshi copper-gold mine (Zambia). Results obtained show that the method provides valuable textural information to achieve a better understanding of mineral behaviour during concentration processes. The potential of this method is enhanced by the fact that it provides data unavailable using current technologies. This opens up new perspectives to the quantitative analysis of mineral processing performance based on textural attributes.CITATION:PTrez-Barnuevo, L, Castroviejo, R and Pirard, E, 2013. New perspectives on quantitative textural analysis, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 191-198 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By Jiuhua Xu, Shuiku Jia, Weiren Sun

"Abstract -The Jinqingding gold deposit, situated in the east Jiaodong Peninsula of Shandong province, is typical of the pyrite-quartz vein gold deposits in the Muping-Rushan gold belt of China . The gold deposit is controlled by a great NNE fracture zone and is composed of several lenticular orebodies within the fracture zone occurring in the Kunyushan granite massif. The Kunyushan granite massif was formed by the replacement of the Archean Jiaodong group.The main minerals associated with gold are pyrite, chalcopyrite, galena and sphalerite; the gangue minerals are dominated by quartz, sericite, microcline and calcite. The mineralizing event can be divided into four stages: (1) pyrite-quartz; (2) quartz-pyrite; (3) siderite-polymetallic sulfides; and (4) calcite-quartz. Gold occurs mainly as native gold and electrum in stage 1 and stage II. There are some evident differences between pyrite from major stages of gold mineralization and that from minor stages; these include differences in crystal forms, size and composition of fluid inclusions.Wallrock alterations consist of sericitization, silicification, pyritization and potash-feldspar alteration. Five alteration zones can be distinguished from unaltered granite (zone 0) to vein lodes (zone IV). Au and Ag increase rapidly from zone 0 to zone IV, Cu increases continuously, while Pb and Zn increase slowly. R-type geological factor analysis indicates that the Au, Ag, Cu, Pb and Zn bear a close relationship to wallrock alteration."

Jan 1, 1994

By Russell Barr

Operational excellence is generally known as a management system integrated across critical functions that is geared towards continually improving operational performance. Functional areas such as health, environment and safety, quality and human resources are the focus of many corporate-wide operational excellence programs. Operational excellence also focuses on improving areas such as customer orientation, employee empowerment as well as process, and systems optimization. It is widely viewed as critical to sustaining business performance improvement. Although it is difficult to find a universally accepted definition, or even common foundation in many respects, operational excellence remains a popular term in the business world. Many organizations have developed their own version of organization excellence, influenced by such individual factors, other similar institutions or even third-party service providers. A mining organization is no different from other organizations in that adopting and implementing effective operational excellence programs can dramatically improve business execution and performance across regional or global interests. This paper brings together various perspectives of operational excellence and reconciles them for a useful composite for the mining industry. While most agree that operational excellence should include normal functions in a manufacturing operation such as production, maintenance and engineering and processes such as quality, environmental and continuous improvement, many other factors for operational excellence seem to vary from perspective to perspective. Thus, programs that manufacturers engage in may seem the same, but may, in fact, be different in key areas. This may affect organizational performance in tangible ways. Management must buy into the company?s definition of operational excellence and be dedicated to achieving it. A review of many of the existing definitions of operational excellence, explicit or embedded as part of a program, seems to yield the following common factors: ? It should help organizations better execute their processes and services. ? It should be geared towards improving quality ? It requires that the various operations should be aligned with the overall enterprise strategy. ? It should be geared towards continuous improvement. A composite of operational excellence definitions suggest that it is: ? Geared towards helping the organization achieve sustained profitability; ? tied to strategic alignment and business objectives; ? tied to solid investment strategies; ? integrated as part of the culture, process, time plan and performance; ? a relevant performance measurement system; ? extended to include all aspects of the supply chain (including external suppliers); ? integrated with health, safety and environmental (HSE) aspects. And, while the pursuit of operational excellence intuitively suggests that businesses should improve, it is very difficult to achieve given the difficult challenges facing companies today. Mining businesses face numerous pressures to perform in a global marketplace such as demand, energy cost, variable cost and pricing fluctuations as well as infrastructure challenges to further confound the environment. Companies generally must look to the following:

Jan 1, 2009

By Lawrence L. Brown

As part of the Federal effort to help maintain an adequate supply of fertilizer materials, the Bureau of Mines conducted research to characterize complex low-grade Michigan phosphate materials and to devise methods for recovering fertilizer-grade phosphate concentrates. The rock is from middle Precambrian sedimentary formations in the Marquette Range located in the central part of the Upper Peninsula of Michigan. Occurrence of phosphate-bearing sediments in Precambrian rocks is rare. This deposit, containing 12 to 15 pct P2O5 is believed to be the richest Precambrian phosphate deposit in the United States. Petrographic examination showed that the conglomeritic rock contains crystalline apatite both in "black pebbles" and in quartz matrix. Attrition scrubbing and sizing tests showed that there is no tendency for phosphate to concentrate in any of the sized fractions. In beneficiation tests, which included grinding to minus 325 mesh followed by phosphate mineral flotation using a fatty acid-fuel oil collector, a phosphate concentrate was obtained that had a grade of 30 pet P2O5 and a P2O5 recovery of 72 pct. This concentrate should be suitable for fertilizer manufacture.

Jan 1, 1982

By W. F. Faragher

The principal equipment in the catalyst plants at Ludwigshafen-Oppau was inspected and is presented in the form of flow sheets for the manufacture of four of the principal catalysts. The equipment is in many cases of special design rather than stock items that was built by the company and modified in the coarse of the growth of the high-pressure synthesis of hydrocarbons in Germany. It is believed that if the manufacture of catalysts were to be undertaken elsewhere, the selection of equipment for the operations involved could be made successfully from the guidance furnished by this rather general report. Five additional catalysts are described, also. II. CATALYST 5058 FROM FRESH TUNGSTIC ACID In a supply tank of about 2,000 liters capacity, 500 kg. of tungstic acid (W03.H2O) that contains about 92-93 percent of W03 is dissolved at 60-70° C. in 1,500 liters of mother liquor. The solution is-effected by stirring for about 1-1/2 hours. The mother liquor is obtained from a previous, lot of catalyst and is first adjusted to a concentration of 13 percent 1H3 by passing in gaseous ammonia. The solution is allowed to stand without stirring for 1 hour, then is pumped into the saturating vessel through a cloth filter (three-quarters hr. to one hr.). The saturator is purged with H2S and thereafter the solution, which has been cooled to about 75° C., is heated in an atmosphere of hydrogen sulfide with stirring to about 70° C. This charge is slowly cooled to 50°, and then more rapidly to about 20° C. (time of cooling 6-7 hours).

Jan 1, 1946

By D. Yu, T. A. Utigard, M. Barati

"Sulfation roasting of nickel concentrate to generate water-soluble metal sulfates was investigated as an alternative process to smelting for the recovery of valuable metals. The kinetics of dissolution of various species of the calcine in three leachants was studied; hot water, dilute HCl, and concentrated HCl. The results indicated that dissolution of sulfates by hot water at 90 ºC is achieved within 30 minutes. In order to increase the recovery of the valuable metals, acid leaching is necessary due to the existence of ferrite in the calcine.INTRODUCTIONInvestigations on the sulfation roasting of nickeliferous sulfide ores or concentrates were mainly carried out in 1950’s to 1990’s to generate water soluble non-ferrous metal sulfates followed by metal recovery by leaching (Stephens, 1953; Thornhill, 1954, 1961; Fletcher and Shelef, 1964a, 1964b; Fletcher and Hester, 1964; Frankiewicz, 1977; Norrgran, 1983). Commercialization of the sulfation roasting process was only performed by Falconbridge Ltd. (Thornhill, 1961; Boldt, 1967), which employed a sulfation roast process on nickeliferous pyrrhotite at 680 oC where Ni, Cu, and Co were leached and Fe2O3 was produced for the iron industry. In 1965, 118,342 tons of pyrrhotite was processed, however because of the huge SO2 emissions (no acid plant) relative to the nickel production and the poor economics, this plant was shut down.Nickel production from sulfide ores via pyrometallurgical means, especially the electric furnace smelting process, is a major emitter of SO2 to the environment and a big energy consumer (Warner, Diaz, Dalvi, Mackey, Tarasov and Jones, 2007). Nowadays, due to the more stringent environmental regulations as well as the need to reduce energy consumption, metal production by sulfation roasting is gaining more attention as an alternative process to smelting. The main focus of this paper is to investigate the extent and rate of leaching of valuable metals from the sulfation roasted nickel calcine, aiming to maximize the metal recovery and minimize the dissolution of iron species."

Jan 1, 2012

By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By I. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of Papua, Indonesia. This district consists of underground and surface operations. The East Ertsberg skarn system (EESS) is one of the major orebodies in this district. Subsurface caving of the EESS has been carried out in a systematic series of mining lifts dating back almost 30 years. Present production from the third lift deep ore zone (DOZ), has reached 80 kt/d (88,000 stpd) during 2010, with this rate sustained through 2015. The orebody was proven below the existing caving level, with the next vertical block called the deep mill level zone (DMLZ).

Jan 1, 2010

By Rafael Valencia-Dongo, Ernesto Ramírez, Julio Tapia

Enfocado en una novedosa metodología de resolución de conflictos basada en la teoría de juegos, este artículo propone estrategias para generar un equilibrio estable entre empresa, Estado y comunidad. Tras evaluar la tipología y características de la conflictividad socioambiental por acción de líderes opositores a la inversión, se desarrolla un marco de resolución de conflictos a través de lo que se denominan pactos de contrapeso, que cubren los ámbitos de comunicación, gestión sociopolítica y fidelización del trabajador minero. Estos pactos permiten cambiar la percepción, incentivos y acciones de los actores, lo que incluye la acción de terceros legítimos.

Sep 30, 2019

By Mosquera. J.

Tailings Storage Facilities (TSFs) are vast structures that respond to site-specific characteristics, rate of production, placement techniques, and the physical and mechanical properties of tailings. As a common denominator, TSFs are in some degree vulnerable to failure due to liquefaction, poor management, slope instability and/or unusual climatic events. In practice, stability of TSFS is determined by calculating a minimum Factor of Safety (FOS) using the Limit Equilibrium Method (LEM). However, it has been proven that relying exclusively on the limit equilibrium approach is not accurate because it is basically a static method that does not take into account the stress-strain distribution and displacement experienced by the constitutive materials of a TSF. In order to overcome these limitations of the LEM, the finite element method - Shear Reduction Technique (SRT) has been used as a more reliable tool for TSFs stability assessment. This paper presents a comparative stability analysis between an upstream tailings storage facility (UTSF), and a water retention tailings dam (WRTD) under static and pseudo-static states using simplified and rigorous LEMs and the SRT. Additionally, and taking into consideration the intrinsic uncertainty of tailings properties, sensitivity and probabilistic analyses in the form of Monte Carlo Simulation (MCS) and the Point Estimate Method (PEM) are applied to determine the Probability of Failure (Pf) and Reliability Index (ß) of each TSF. It is shown that the friction angle of UTSF?s foundation and the core?s cohesion of the WRTD are the main variables that govern stability. Further analysis shows that the WRTD has a higher reliability index and a lower probability of failure than the UTSF.

Aug 1, 2013

By William J. Campbell

This analytical method development and evaluation was undertaken by the Bureau of Mines to provide accurate determinations of eight minor elements in low-alloy steels prepared from ferrous scrap. Fluorescent X-ray spectrography was the principal method investigated. Confirming analyses were made by conventional instrumental and chemical methods. All X-ray data were processed by a timesharing computer. No corrections were found necessary for inter-element effects or overlapping spectral lines. Concentrations were calculated from the least-square fit of a linear calibration equation derived from measurements on three sets of standard steels. These studies show that X-ray spectrographic analysis of lathe-finished surfaces provides accurate determinations of aluminum, copper, chromium, manganese, nickel, phosphorus, silicon, and tin.

Jan 1, 1973

By N. B. Brown

ABSTRACT The effect of a low4emperature stress relief at 232.2°C. (450°?F.) on the fatigue properties of shot-peened SAE. 1080 steel has been investigated. Specimens of the steel were first annealed. One half of the steel bars were then normalized and the other half were water-quenched and drawn. Specimens of the steel with each heat treatment were tested in tensile, notched bar impact, and fatigue. The fatigue specimens were test in air and water in R. R. Moore high-speed rotating bending machines in the following conditions: un-peened, peened, and peened-and stress-relieved at 232.2°C. ( 450°F.) The 'endurance life' and fatigue properties of specimens given a stress relief heat treatment after shot peening were superior to those of specimens given a smooth machine finish or shot peened. INTRODUCTION THIS investigation was initiated to obtain preliminary information on the effect on the fatigue resistance of shot peening the machined surface of a high-carbon steel similar in composition to that used in hollow drill steel. The data obtained in this investigation could be applied in analysing the application of shot peening hollow drill steel shanks. It is well known that the 'endurance life' and fatigue limits of steel are greatly ?improved by shot peening. References to this in the literature are numerous.

Jan 1, 1951

By Y. W. Chung, W. I. Chia

"The interaction of water vapor with single crystal Ni3(Al,Ti) and polycrystalline Ni3Fe, with and without the presence of oxygen, has been studied with Auger electron spectroscopy, photoemission spectroscopy, thermal desorption and isotope exchange. Water dissociates to produce atomic hydrogen above 200 K on both Ni3(Al,Ti) and Ni3Fe surfaces. For Ni3(Al, Ti), the reaction is structure-sensitive. Pre-adsorbed or co-adsorbed oxygen on Ni3(Al,Ti) and Ni3Fe significantly suppresses hydrogen production due to water dissociation. This suppression process occurs more efficiently on Ni3Fe than Ni3(Al, Ti).IntroductionOrdered intermetallic compounds such as aluminides, silicides and titanides are very attractive for structural applications at high temperatures. This is because these intermetallics tend to form adherent oxides in oxidizing environments which protect the base materials from excessive oxidation and corrosion. In addition, they have low density, relatively high melting points and good high-temperature strength. However, the moisture in air severely embrittles many ordered intermetallics such as FeAl [1-3], Fe3A1 [4,5], C03Ti [6,7], (Co,Fe)) V [8], Ni3Si [9], Ni3(Si,Ti) [10], Ni3(AI,Mn) [Ill, and Ni3A1 [12-14], resulting in low 'ductility and brittle fracture at room temperature. Recent studies by Liu and coworkers (see review by George and Liu [15]) provide a qualitative description of the mechanism for this moisture-induced embrittlement. During elongation testing, cracks are formed, thus exposing fresh alloy surfaces. One or more active components of the alloy react with water vapor in the environment to produce atomic hydrogen which penetrates into crack tips and causes hydrogen embrittlement. This is similar to that proposed for moisture-induced embrittlement of aluminum alloys [16]."

Jan 1, 1996

By Frank M. Kimmerle

Spent Potlining (SPL) contains recoverable chemical elements (C, F, Na and Al) which are lost in stabilization or immobilization processes primarily aimed at eliminating cyanides and reducing leach rates of soluble fluorides prior to landfiling. They can be recovered in a variety of mineral forms for recycling in the aluminum industry and elsewhere. Alcan has developed a cost-effective hydrometallurgical route, combining a number of proven unit processes to destroy cyanides, recycle the chemical values and provide a zero-discharge process. Pilot plant studies of this Low Caustic Leach and Liming (LCL&L) Process prove that the fluoride scan be converted to acid grade fluorspar, while the sodium and aluminum are recovered as a sodium aluminate and caustic feed to the Bayer Plant operations. The remaining brick and carbon fraction constitutes a high ash solid fuel which meets TCLP leach criteria and whose reduced sodium content enhances its value as a chemical reducing agent.

Jan 1, 1994

By Zbigniew Lubosik, Andrzej Walentek, Stanislaw Prusek, Aleksander Wrana

"The Carboniferous coal measures, mined across Europe including the major European underground coal mining countries of Poland, UK, Germany, and Czech Republic, suffer from increasing extraction depth. This results in major geomechanics problems associated with ground control and support design.With production being concentrated into ever fewer high performance longwalls, located at greater and greater depth, pressure to ensure the roadways’ functionality (required dimensions) continues to increase. Mining in deeper and more highly stressed mining environments creates several problems. The high stress and deterioration in geological and mining conditions in many cases causes problems with gateroads maintenance (due to excess convergence). That leads to costly production gaps, longwall slowing, transport problems, an increase in the methane hazard and in the general health and safety of the workforce, and deterioration in climatic conditions with major economic risk associated with interruption of the revenue stream. Time—and thus production—delays due to maintenance often result from insufficient geological and geotechnical data acquisition and misinterpretation combined with inadequate support for the type of rock mass.longwall face on the gateroad stability (described by the gateroad convergence, support load, and shape and height of the fractured zone around the longwall gateroad) are presented. The investigations were carried out in the longwall panel with roof caving located at the great depth, in conditions of the Upper Silesian Coal Basin in Poland.The measurement results showed that the gateroad fractures in roof strata began to occur at the distance of about 1000 m ahead of the face. Additionally, the load on support and gateroad convergence increased as the longwall face got closer.It is very important for coal mining research institutes and mine operators to investigate and develop practical solutions and apply innovative support technologies at a great depth (particularly for reinforcement and stabilization of roadways and other openings).Underground measurements of stability conditions around the gateroad is of great importance to mining practice, especially in planning and designing supports for longwall gateroads.The influence of the front abutment pressure results in an increase of support load, gateroad convergence, and shape of fractured rock zone."

Jan 1, 2015

By Thomas Clark

This report presents a review of the distribution and exploration potential of platinum-group elements (PGE) in Québec; it is based on published and unpublished analytical data. This qualitative evaluation of the PGE potential, whether in PGE-dominant deposits or in Ni-Cu-dominant deposits with co-product PGE, is based on interelement ratios such as Ni/Pd, Cu/Ir, Cu/Pt, and Cu/Pd. Good PGE targets, i.e., deposits associated with magmas fertile in PGE, are identified. Less favorable PGE targets, i.e., deposits associated with PGE-depleted magmas, are also mentioned. The importance of exploring for deposits similar to those at lac des Îles and East Bull Lake (Ontario) is emphasized.

May 1, 2001

By M Edwards

The paper outlines the successful application of some of the on-belt technologies available from Scantech International Pty Ltd and how these have provided benefits in a number of mining and mineral processing operations. Effective process control requires real time analysis so quality can be fed back to the previous process and fed forward to a subsequent process. A range of on-belt analysers that allows for full stream, continuous, non-contact analysis of conveyed materials is available to achieve this. Real time results can provide timely information for effective process control. Benefits of on-belt analysis systems become more evident once the true variability of material quality and moisture content in conveyed flows is measured. To obtain economies of scale in mineral processing operations large material flows are achieved using conveyors. The cost and effort to sample representatively increases as conveyor flows increase. One sample may represent a few tonnes or up to 10 000 tonnes of material. The turnaround time between sampling and availability of sample analysis data does not allow real time process control. Tonnage flow rate, moisture content and elemental or mineralogical composition are required to perform effective process control of most conveyed streams. Tonnages can be effectively measured using belt weighers. The analyses derived from small samples supplied by conveyor-based sampling systems contain high variability. On-belt, continuous analysers see all the material and, through short term compositing of analyses, supply less variable results. Real time analysis helps operators develop a better understanding of material variability. Analysers can be effectively utilised to improve the consistency of product quality through bulk sorting and blending control. Many existing users of the technologies have gained competitive advantages through their ability to supply a more consistent quality product to the market.

Jan 1, 2008

By A Jakowetz

OxianaÆs Sepon Copper Operation (part of the combined Sepon Gold and Copper Operation) is located in Savannaket Province, in southern central Lao PDR. The site is relatively remote, being some five hours inland from the Laos/Thailand border crossing on the Mekong River. The copper processing plant was designed to treat 1.3 Mtpa ROM ore to produce 60 000 tpa of copper cathode. Commissioning of the processing plant was completed in mid March 2005 with ramp up completed in January 2006 with 5260 tonnes of cathode harvested in this month. The focus of this paper is on SeponÆs unique grinding circuit. The entire grinding circuit is operated at highly acidic conditions, adding a number of different operational issues over and above those normally associated with grinding circuits. It became evident early in the ramp up, that reaching design mill throughput of 170 dry tonnes per hour with the original design would be challenging, coupled with the realisation that ceramic grinding media consumption had been underestimated. In order to lift the overall throughput of the processing plant, a significant continuous improvement process has been implemented within the grinding circuit to lift this key unitÆs production capacity. This presentation will focus on the key areas that have been addressed in the 12 month ramp up period and highlight areas for future work. Results to date have shown this improvement process to be very successful, with throughput rates in excess of 200 tph regularly achieved.

Jan 1, 2006

By Inkap Choi

Asbestos is a broad term embracing a number of fibrous silicate minerals. These minerals look extremely fragile, yet their fibers have a tensile strength equal to that of piano wire. Chrysotile asbestos is the only mineral that can be woven into cloth, and its fibrous structure is, if anything, even more amazing than its remarkable ability to withstand heat. Because of its unique physical properties asbestos has achieved great industrial importance, and more than 3,000 current uses are known, ranging from use in the kitchen to use in space missiles. Because their minuscule fibers are eminently respirable, asbestos minerals have also found their way into the lungs of humans, where they apparently produce serious biological effects such as asbestosis and lung cancers. 1, 2,3 Because of both their usefulness and their hazardous properties, these minerals have attracted a good deal of attention from research workers during recent years. For example, the surface properties of asbestos minerals have been studied by many investigators. 4, 5, 6, 7, 8, 9 However, even for the important mineral chrysotile, the literature data are more or less conflicting. Pundsack4 measured a PZC (point of zero charge) of 10.1; Martinez and Zucker5 measured 11.8; Chwastiak reports 10.8-11.0; and Raddick measured three sepa-rate apparent PZCls at about pH 8.3, 10.0 and 10.9. More recently Trivedi8 reports 10.11. Naumann and Dresher9 have studied surface charge enhancement of chrysotile by metal ions, and describe how the mineral reacts with contaminantions. In the present paper, the mode of dissolution of magnesium and hydroxyl ion from asbestos minerals placed in water was studied by kinetic experiments involving rate at which these items leave the minerals. Also, some study was made of interaction between dissolved species.

Jan 1, 1972

By Theodore Ineich

The “BIOMOre” project aims to prove the technical feasibility of indirect in situ bioleaching of sulfide minerals contained in a deep underground deposit, by bringing together the disciplines required to make a success. The underground location in Poland was provided by project partner KGHM inside an operating copper mine. Key components of this project were the design and construction of a pilot plant, and its operation in an underground environment. This project also included a ∼250 t (100 m3) fragmented rock reactor hydraulically connected to the pilot plant. The pilot plant consisted of several tanks and pumps, a fluidised bed ferric iron generating bioreactor containing immobilised acidophilic iron oxidation biomass, and all the required instrumentation and utilities. Before the bioleaching phase could start, the rock reactor had to be flushed continuously firstly with water to remove chloride salts that are corrosive and also harmful for the bacteria used in the bioreactor, and secondly, with sulfuric acid solution to react with the carbonates present in the ore matrix. This paper summarizes the design, construction, commissioning, and operation of the pilot plant.