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By Efrem R. Reeves, David C. Byrne

This study was conducted as part of a project involving the evaluation of a new type of noise exposure monitoring paradigm. Laboratory tests were conducted to assess how “nonstandard” dosimeter microphones and microphone po­sitions measured noise levels under different acoustical condi­tions (i.e., diffuse ?eld and direct ?eld). The data presented in this article re?ect measurement differences due to microphone position and mounting/supporting structure only and are not an evaluation of any particular complete dosimeter system. To varying degrees, the results obtained with the dosimeter microphones used in this study differed from the reference results obtained in the unperturbed (subject absent) sound ?eld with a precision (suitable for use in an ANSI Type 1 sound level meter) 1/2 -inch (12.7 mm) measurement microphone. Effects of dosimeter microphone placement in a diffuse ?eld were found to be minor for most of the test microphones/locations, while direct ?eld microphone placement effects were found to be quite large depending on the microphone position and supporting structure, sound source location, and noise spectrum.

A good deal of experimental work has been done from time to time on the application of compressed air to the elevation of wet pulp. On account of the flat nature of most of our mill sites elevation of the pulp has to be provided for, and the various methods in vogue show considerable loss of time, in the replaceing of wearing parts. During the last two years the writer has carried out a great many experiments with a view of devising an elevator that will give continuous work with a minimum of wear.The results do not show a high efficiency for the power employed, but the lift is continuous in operation, very cheaply installed, and possesses no wearing parts. The lift was tried working in a bore hole of 8 in. diameter, but in many cases it is more convenient to sink a small well for the purpose. The result to date showed that the most efficiency was obtained when the depth of the wellwas not less than the height of the lift required. The pressure of air required in pounds per square inch was (approximately) half the number of feet to be lifted.In the majority of cases the lift required varied between 20 ft. and 50 ft. and the air pressure required between 10 lbs. and 25 lhs. per square inch. In most existing installations the air compressors in use were delivering air to the receivers at about four times that pressure, and when air so compressed was expanded to perform its work at a reduced pressure, it was apparent that the power exerted in origInally compressing the air above the working pressure required at the lift was absolutely lost.

Jan 1, 1901

By B. Soundara, A. Suganya, S. Selvakumar

"Expansive soils have a potential for shrinkage or swelling under changing moisture content. Attempts were made to reduce the swelling potential of expansive soils with conventional additives such as lime, cement, etc. and non-conventional additives such as industrial wastes. In this research an attempt is made to study the feasibility of using granulated waste expanded polystyrene (EPS) as an additive to expansive soil to control swelling. To investigate the effect of mixing waste EPS granules with expansive clays, three expansive soils with different plasticity index were manufactured in the laboratory by mixing sand with sodium bentonite of various proportions. A series of standard proctor test, California bearing ratio (CBR) test, one dimensional free swell and swell pressure tests were performed on these soils. Test results show that the inclusion of EPS granules significantly reduces the percent swell and swelling pressure when subjected to one-dimensional free swell conditions. The dry density and CBR values decrease with increase in EPS content and increased plasticity of the soil.INTRODUCTIONExpansive soils cover an area of about 257 Million hectares on the earth’s surface (Dudal et al. 1965). In India, the area covered by expansive soils is nearly 20 percent of the total area (Mohan et al. 1961). Movement is usually in an uneven pattern and of such a magnitude as to cause extensive damage to various structures, especially lightly loaded structures or pavements (Chen 1975). Stabilization is one of the methods of treating the expansive soils to make them fit for civil engineering purposes. The variety of stabilizers may be broadly divided into three groups (Petry et al. 2002): (a) traditional stabilizers (lime, cement etc.), (b) by-product stabilizers (fly ash, quarry dust, phosphor-gypsum, slag etc.) and (c) non-traditional stabilizers (sulfonated oils, potassium compounds, polymer, enzymes, ammonium chlorides etc.). Apart from these, a number of other ground improvement techniques such as sand cushion technique (Satyanarayana 1966); cohesive nonswelling (CNS) layer technique (Katti 1978) were adopted for the stabilization of expansive soils. Expanded polystyrene (EPS) is a polymeric foam normally available in white colour and is a wellknown packaging material. The geotechnical specialists recognize EPS as the most commonly used geofoam material, a type of cellular geosynthetic which has been in consistent use in geotechnical applications since the early 1960s (Horvath 1995). EPS has very low thermal conductivity and nearly 98% of the volume is air (Lye et al. 2002). EPS has many exceptional properties such as being lightweight, thermal insulating, shock-absorbing and having low-water pick-up, etc. EPS find its applications in geotechnical engineering as light weight fills in the form of blocks (Refsdal 1985, Karpurapu et al. 1992, Zou 2001, Ikizler et al. 2008). EPS can be used as compressible inclusion and as a vibration damper (Horvath, 1994&1995). EPS is also used in lightweight concrete owing to its lightweight, excellent heat preservation and sound insulation properties (Ravindrarajah et al. 1994; Miledet al. 2004 and Babu et al. 2005). Waste EPS granules have been used in with horticultural soils to improve a number of soil characteristics like improving drainage, lightening heavy soils and improving water uptake capacity of soils (Scheirs 1998). Furthermore, it was also used as sub-base materials for pavements and railway track beds (Hanna 1978; Duskov1996), construction materials for floating marine structures and fenders in offshore oil platforms (Bagon et al. 1976), sea beds and sea fences; as an energy absorbing material for buried military structures, (Perry et al. 1991)."

Jan 1, 2017

By Libby R. Ricafort, Victorio V. Pato, R. S. Pizarro

Introduction Atlas Consolidated Mining and Development Corp. (ACMDC) started gold production at its Masbate gold mine early in 1980. This involved an open-pit mine and a 3.5-k/d (3850-stpd) carbon-in-pulp processing facility (Pizzaro and Antonio, 1981). When this operation started, the mine began stockpiling sub-grade milling material averaging 1 g/t (0.029 oz per st) gold. Furthermore, geologists estimated that there were additional low grade reserves within the ultimate pit limits. These amounted to 2.4 Mt (2.6 million st) with an average grade of 1.1 g/t (0.03 oz per st) gold. The success of low cost heap leaching prompted an investigation to determine if this tech¬nique would be applicable for the low grade Masbate ore. The findings were favorable and a series of laboratory tests were undertaken. These tests indicated the amenability of this subgrade milling ore to heap leaching. Depending on ore size, gold extractions of more than 60% were obtained. To further define operating parameters for a commercial heap leaching plant, a 400-t (440-st) batch pilot plant was built and operated. These test results were used to design the first commercial heap leaching plant in the Philippines. One design concern was the control of solutions during the rainy season. Due to the material's low grade, every effort was made to minimize capital and operating costs. To this end, surplus mining equipment from the copper operations of ACMDC and used machinery in the crushing circuit were considered. Location: The Masbate gold heap leaching operations are located on the northeastern part of Masbate Island, Philippines. This is about 480 km (300 miles) south-east of Manila. Climate: The climate is moderate with two distinct periods. The dry season runs from January through June, and the rainy season extends from July through December. During the wet season, the rainfall at the mine site averages 300 mm/m (11.8 in. per month) for a total of about 2000 mm/year (78 in. per year). However, heavy downpours in excess of 100 mm/h (4 in. per hour) can occur. Geology: Four distinct rock types have been identified in the pit area. They are tuffaceous agglomerates, andesitic agglomerates, metasedimentary rocks, and hornblende augite andesitic porphyry. The tuffaceous agglomerate occupies the northern and western flanks of the mine. Andesitic agglomerates are localized distinctly in the central portion of the volcanic plug within the mine site. The eastern boundary of the mine is occupied by metasedimentary rocks, whereas, the hornblende augite andesitic porphyry occurs as an intrusive within the andesitic agglomerate and tuffaceous agglomerate. Some areas of the pit contain high proportions of clay minerals, requiring an agglomeration step in the flowsheet. This ensures satisfactory percolation through the heaps. Ore characteristics: Gold and silver are microscopically dis-

Jan 9, 1987

By Andrew P. Jarosz

The present computerized mine planning systems use CAD-like and Data Base Management System (DBMS) environments for the handling of numerical, textural, and graphical data. These two environments are usually integrated, that the data provided by the DBMS are linked to any graphical element rendered by the CAD system. The subsidence monitoring, analysis and prediction process should be integrated with the mine design process. It should allow for the assessment of impacts of mining on surface, surface utilities, and structures. It should also provide for the measures to control mining, that will create only acceptable levels of negative impacts on the surface. The common data base, and graphical capabilities of the CAD interface, may be used with great advantage for both systems. The findings of the subsidence engineering modulus should be directly incorporated into the mine design system, and vice versa. In this paper the author suggests guidelines for the development of the comprehensive computer system, able not only to predict the vertical and horizontal components of the ground movement, but also assess the induced surface damages, and costs related to subsidence prevention and compensation.

Jan 1, 1995

By Barry C. Slocombe

The development of new ports, extensions of existing facilities and reclamation of former docks will involve consideration of a variety of geotechnical problems. This paper presents data including instrumentation of structures from three UK projects involving vibro techniques to provide economic engineering solution.

Jan 1, 2008

By L. M. Dyer

Various attempts have been made to build leadership and management expertise with little success. There are numerous reasons these attempts have failed. Three reasons, along with suggested solutions, will be explored: 1) lack of ownership of the development process by those affected; 2) lack of congruence of the development process used and the business strategies of the organization; and 3) a comprehensive development process. We will discuss a development model applied inside a smelter and refining complex over one year involving all levels of management. The process was credited with helping to substantially reduce cost and enable breakthroughs in production, quality and safety results.

Jan 1, 2000

By Manuel Retamozo

El presente texto señala cómo el ejercicio físico adecuado y la dietética mejoran la producción y disminuyen el absentismo laboral en la empresa minera BHP Billiton Tintaya S.A a través de un política de prevención de salud. Entre los objetivos principales está determinar la frecuencia con que realizan ejercicio físico adecuado los trabajadores del área de mina, señalar si existieron cambios en las costumbres alimenticias de los trabajadores del área de mina después de la educación alimentaria, delimitar si existe asociación entre el aumento de la producción en el área de mina con la práctica del ejercicio físico adecuado y la dietética, así como entre la disminución del absentismo laboral en el área de mina con tales prácticas.

Jul 31, 2003

By Forrest T. Moyer

Need for lightweight building materials was created in the latter part of the nineteenth century by a radical change in building design in which dead load or structural weight was transferred from thick, heavy, load- bearing walls of former construction practice to a load-carrying framework of beams and columns with thin walls. This new design was brought about by the introduction of structural steel followed by reinforced concrete and structural concrete as materials for the erection of the load-supporting frame. The new materials and method of construction made possible the erection of skyscrapers and the building of bridges with long spans, and made feasible additions of one or more floors to existing buildings. As size and design of the load-bearing framework are controlled chiefly by dead load, the natural result was a. search for and use of light- weight materials in partitions, floors, and exterior walls. However, these thin walls created problems of heat and sound. insulation, so that building materials which possessed good heat- and sound-insulating properties in addition to light weight were objects of extensive research. One group of materials developed to fill this need comprised lightweight concretes, of which some were obtained by the use of lightweight aggregates. Although the advantages of lightweight.materials were evident from the first skyscrapers, there was a transition.stage.between the old bearing- wall and modern skeleton-frame types of building, with the heavy and massive construction of the former superimposed upon the latter. Hence, it was not until the period between 1910 and 1930 that the new lightweight concretes were recognized and used more extensively in the erection of large, nonresidential buildings. From this type of construction, light- weight-aggregate concretes entered-fields of residential and small non- residential building; in which they were found desirable for production of prefabricated, large-size; masonry units. Although the weight of each unit was reduced sufficiently to enable one man to handle it easily, properties of the new concretes other than light weight were the principal factors in the ready acceptance of these new materials in residential building. Manufacture of precast units includes complete lines of masonry and back-up blocks, bricks; floor beams, columns and partition, roof, and floor tiles and slabs. Recent improvements in casting machinery, development of the vibration-pressure machine, and a more thorough study and knowledge of the requirements and properties of the concrete mix have all contributed materially to the rapid expansion in use of lightweight aggregates in this industry.

Jan 1, 1942

By James H. Owen

Because of price structure, ANFO is normally considered to be the most cost effective explosive used in quarry blasting. Results indicate that bulk smulsion can be more cost effective in applications where hole sizes range up to 6.5 inches in diameter while providing the simplicity of single product loading and storage. This can be accomplished without any fragmentation and/or movement loss usually in patterns which are about twice the size of ANFO patterns, allowing the combined drilling and blasting cost to be less when using bulk emulsions. Examples are presented supporting this concept using actual field results along with some simple calculations which take into account differences in the products such as density, matrix and detonation velocity.

Jan 1, 1998

The history of mining is rightly proud of its achievements in improving productivity and cost improvements over the years. No matter what measure is used, tonnes per manhour, cost per tonne, etc vast improvements have been made over the last hundred years. In fact over the last ten years in Australian coal mines raw coal output per employee has increased by 60 per cent. When one examines why these improvements have taken place the principal reasons have been technological advancement in mining equipment, excavator and dump truck capacity increases, longwall and continuous miners continually improving in reliability and size. Of course all these improvements are correlated to an increase in capital cost. Even with the above-mentioned advances the pressure for increased performance is as strong as ever. The international mining and mineral-processing sector is currently operating in a recessive market with some traditional commodities, eg gold trading at 20 year lows. During recessive times senior management will demand greater returns on capital employed: the obvious choices being reducing costs or increasing throughput. In addition, head office environments will often place a capital freeze on operational management so the opportunity to take advantage of technological change is not available. The challenge is, therefore, to increase throughput and cut costs without the need for capital. The answer is to optimise the existing labour and plant. If done systematically a result in productivity improvement, in our experience, as high as 45 per cent can be achieved with the average across South East Asia and Australasia being 21 - 23 per cent. The intention of this paper is to present a systematic approach to labour and machine utilisation thereby gaining the greatest possible return on the existing capital base.

Jan 1, 1999

By Samuel J. Gambino

Preliminary recommendations for the Upper Northwest Interceptor 1&2 specified installation of reinforced concrete pipe using pipe-jacking methods. However, a larger one-pass tunnel constructed using precast segmental lining would provide additional storage volume. The risk of encountering unexpected conditions or events and the resulting cost impacts could differ significantly for these two options. A probabilistic life-cycle cost analysis of these alternatives was performed. This paper discusses the construction alternatives considered, the risk assessment methodology used to evaluate these alternatives, the input parameters and risk factors used in this analysis, and the recommended project which is currently being constructed.

Jan 1, 2008

By Jasper L. Stuckey

PYROPHYLLITE, first identified as soapstone,1 later as agalmatolite,2 and finally as pyrophyllite,3 has been known to occur in North Carolina for more than 130 years and has been produced intermittently in commercial amounts for the past 100 years. Pyrophyllite mining, however, has become a major industry in North Carolina only during the past 25 years. North Carolina and California are the chief producing states. Current annual production averages 125,000 tons, of which slightly more than 90 pct comes from North Carolina. Distribution and Geologic Setting: All known pyrophyllite deposits in North Carolina are associated with rocks of the Carolina Slate Belt,4 which is composed of a vast series of metamorphosed volcanic and sedimentary materials, occurring as two zones extending in a northeast-southwest direction across the state. The larger of these zones, lying in the central Piedmont region, varies from 8 to 50 miles wide. The smaller zone lies along the eastern edge of the Piedmont region and is partly covered by coastal plain sediments.

Jan 1, 1958

By Trevor Yeomans

"NVI Mining’s Myra Falls Operation is a forty year old underground mining operation feeding a 4000 mtpd concentrator.The current Mill, built in 1985, was designed to process a large massive sulphide ore-body. This ore-body, known as the “HW”, contains about 50% pyrite. Value minerals are chalcopyrite, and sphalerite, with precious metals occurring in all mineral types.By 1997, mining of a new ore-body, known as “Battle-Gap” commenced. Mineralogically complex, the new orebody contains about 15% pyrite, copper minerals including primary chalcopyrite, secondary bornite, chalcocite and tennantite, combined with increased galena and sphalerite.Flotation performance generally decreased with increasing amounts of Battle-Gap ore types, with both copper concentrate quality (increased lead and zinc content) and copper recoveries being affected.Following significant metallurgical testwork, a new fully sequential copper-lead-zinc flotation flowsheet and reagent scheme was developed.This sequential flowsheet was progressively installed and commissioned during 2006.Copper concentrate lead and zinc smelter penalty contents have been reduced by some 40%, whilst increasing copper recovery by 10%.INTRODUCTIONNVI Mining operates the Myra Falls Operation near Campbell River on Vancouver Island, BC. The complex has been in operation since 1966 with mining being predominantly underground. One unique feature of Myra Falls is that the mine operates within a BC Provincial Park.In 1985, a new large massive sulphide ore-body (HW) had been defined, and metallurgically tested. A new concentrator was built based upon this massive pyrite, chalcopyrite, and sphalerite mineralization producing copper and zinc concentrates by conventional flotation methods."

Jan 1, 2008

By Stephen J. Roberts

Gold catalysts were prepared on co-precipitated, calcined copper oxide - zinc oxide support by an inverse deposition-precipitation method. These catalysts were characterised by X-ray diffraction (XRD) and temperature-programmed reduction (TPR) and studied for CO oxidation activity at various catalyst calcination temperatures. TPR studies of the support material exhibited a double peak and shift to lower temperatures for the reduction of Cux+ to metallic copper, as opposed to the single reduction peak for pure CuO. This phenomenon is possibly caused by an interaction with the zinc oxide. The addition of gold to the support CuOZnO led to a further shift in copper reducibility to lower temperatures. Gold present in the initial uncalcined catalyst as Au3+ was auto-reduced to Au0 under various calcination temperatures. The Au3+ reduction peak was observed to shift to lower temperatures with increasing calcination temperature. The catalytic activity was found to pass through a minimum value with respect to calcination temperature. Catalysts with both gold in entirely the 3+ or metallic oxidation state were found to exhibit high activity. Furthermore, the catalysts were found to decrease in activity with decreasing Au3+ content up to an intermediate calcination temperature, afterwhich the activity increased sharply. Possibly at higher temperatures, a stronger Au-support interaction is formed, leading to a new active site.

Oct 1, 2003

By C Noble, J Webster-Brown

A survey of selected West Coast Streams was undertaken in Summer 2001, Summer 2002 and Winter 2002 to establish the degree of arsenic (As) contamination in waters and sediments downstream of old coal and gold mine workings on the West Coast. Of the catchments studied, Soldiers/Ford Creek and Rapid Stream showed the most significant elevated As concentrations, predominantly in dissolved form, and evidence of AMD or ARD contamination (high sulfate concentrations and/or acidity). The rate and processes of removal of dissolved arsenic from the water column (attenuation) have been studied in these catchments. The Rapid Stream and Soldiers/Ford Creek catchments are directly affected by adit drainage from the Sullivan and Blackball coal mines respectively. Both catchments have high As concentrations in the sediments, with up to 770 mg/kg in Soldiers Creek and 490 mg/kg in Rapid Stream. Dissolved As concentrations are significantly elevated in the neutral pH waters of Soldiers Creek; typically as high as 100 - 200 ¦g/kg, up to 500 m downstream of the main adit discharge (800 ¦g/kg As). Adit inflows to Rapid Stream were acidic and contained 20 - 30 ¦g/kg dissolved As, with relatively high concentrations of arsenic in the stream water in winter (up to 18 ¦g/kg), but not in summer. Analysis of concentration trends and As:SO4 ratios downstream of these obvious As sources confirmed that dissolved As had been actively removed from the water column, but varied seasonally with greater removal evident in summer. Adsorption of arsenic onto iron oxide in the stream sediments is the most likely mechanism of removal. The Snowy River catchment, on the other hand, has relatively high As concentrations in both the sediments and the water column, but there was little evidence of a distinct AMD or ARD input from the Blackwater gold mining area. Preliminary investigation suggests that dilution rather than attenuation is responsible for decreasing As concentrations downstream.

Jan 1, 2003

By A Giblett, K Afewu

This paper uses a case study to demonstrate best practices techniques for predicting the contribution of gravity concentration in a gold recovery process flowsheet. The case study was selected as an example of an ore with a marginal gravity gold content, which makes the value of a gravity circuit difficult to quantify. In this instance the value of leveraging a significant knowledgebase of operating gravity circuit performance to support the decision making process was demonstrated. This case study analysis serves as a useful demonstration of best practice methodologies supporting decisions to include or exclude gravity recovery in a gold recovery process flowsheet.CITATION:Giblett, A and Afewu, K, 2015. Do we need a gravity circuit or not? A case study in applying best practice, in Proceedings MetPlant 2015, pp 288–295 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By H Li

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The central Nanling region in South China experienced multistage granite intrusive events and corresponding metallogenic processes during the Early Yanshanian period (190–140 Ma). In this study, a wide variety of published data on age determination, petrological characteristics, major and trace elements compositions, whole rock Sr–Nd contents and zircon Hf isotopic composition of the representative granite composites were systematically collected to estimate their cooling-uplift rates, granite evolution processes and mineral deposit formation. These granites have been classified into two groups based on their age and geochemical variations: Group 1 (180–165 Ma) and Group 2 (165–150 Ma). Major and trace element geochemistry suggests that Group 2 experienced more intense magmatic evolution and differentiation than Group 1. In addition, Group 1 granitoids are classified as A1-type alkaline rocks with faster cooling and uplift rates, whereas Group 2 granites are considered as A2-type aluminous rocks with slower cooling and ascent rates. Furthermore, the Group 1 granitoids have younger Nd and Hf two-stage model ages but higher eNd(t) and eHf(t) values, indicating influence from crust–mantle interaction. In contrast, the Group 2 granites show different values, suggesting stronger upper crustal contamination or assimilation. The slowly cooled and ascended Group 2 granites experienced much heavier crustal contamination (or assimilation) and crystal fractionation, contributing to the large W–Sn mineralisation in the central Nanling region. The Early Mesoproterozoic (1.6–1.4 Ga) crustal basement of the Cathaysia Block in South China is the ore source bed for the world-famous Nanling W–Sn polymetallic mineralisation.CITATION:Li, H, 2015. Where is the source of the world-famous Nanling W–Sn polymetallic mineralisation?, in Proceedings PACRIM 2015 Congress, pp 619–622 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By L. A. Thompson, A. J. Linington

"Copper–cobalt extraction is a reagent-intensive process resulting in acid consumption greatly contributing towards production costs, which in the current market conditions curtail profitability. Nanofiltration (NF) membranes have become an attractive approach in the mining and minerals industry for product concentration and reagent recovery based on the ability of the membrane to separate monovalent ions from divalent ions. NF membranes can selectively separate acids from metals and salts allowing acid to be recycled as well as the concentration and purification of product streams. Membrane technology in the field of copper–cobalt processing focusses on the concentration of Cu2+ and Co2+ in the pregnant leach solution, recovery of acid from waste streams to neutralization, recovery of valuable metals from waste ponds and process water recovery. This paper aims to provide insight into the potential applications of NF membranes in copper–cobalt processing circuits as well as a brief overview of the effects of process conditions on membrane performance and process development. INTRODUCTION The copper–cobalt industry commonly uses inorganic acids, such as sulfuric acid, in large quantities for primary leaching of copper–cobalt oxide ores and releaching during product purification (Stuurman et al., 2014). This results in numerous acidic intermediate streams containing high metal concentrations and acidic waste streams with low metal concentrations. Acid consumption typically accounts for 10–15% of the operating costs of mines in the Democratic Republic of Congo (DRC) and Zambia (Acid Plant Database, 2015). Due to remote mine locations, poorly maintained roads and cross-border conflict, the cost of sulphuric acid can range between USD 300 and 400 per ton. The pivotal role of acid in the copper–cobalt extraction process has driven many mines to build sulphuric acid plants on site to ensure a reliable acid supply, however elemental sulphur still needs to be imported which faces similar logistical challenges and contributes towards operating costs."

Jan 1, 2015

By Viviane Tavares

The technology advance of mobile devices makes consumers of these equipment do more constant exchanges, with this the obsolete devices discarding becomes an environmental problem, due its landfill accumulation. In order to minimize the environmental impacts caused by these equipment there?s the recycling necessity of polymers, ceramic and metallic materials. The main goal of this recycling is to study the printed circuit board of device mobile processing through ore treatment in order to recoup copper. Initially printed circuit boards were processed in a knives mill, in order to liberate the ferrous material, after that it was done the magnetic separation of the reduced residue. With the not magnetic fraction it was done the grain sized analysis and sulfuric acid and hydrogen peroxide leaching analysis. With the chemical analysis results proceeding from the leaching aliquot it was possible to observe that the leaching method with sulfuric acid and hydrogen peroxide presented greater copper recovery.

Jan 1, 2009