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By J. D. Potts

Dust surveys were conducted at six underground coal mines to determine if deep-cutting practices expose face workers to higher levels of respirable dust. The surveyed mines were able to successfully mine deep cuts without significantly increasing the dust exposures of face workers. For exhausting face ventilation, field data indicate that scrubber airflow is the most important factor for controlling dust. Data collected for this study indicate that 20-mesh screens should be cleaned for every 40 ft of advance because 22% of the deep cuts surveyed for this study experienced a 20% to 35% decrease in scrubber airflow over the course of the cut. For blowing face ventilation, field data and past research indicate that dust control is aided by maintaining a proper curtain-to-scrubber airflow ratio of 1.0 (measured before scrubber activation) as well as a curtain setback distance that allows the miner operator to stand at the mouth of the curtain for the entire cut. Dust levels on the bolting faces did not appear to be affected by the longer cycles associated with deep-cut mining when good ventilation practices were used.

Jan 1, 2011

By L. Westerstrom

Supply and Demand After a dismal first half, the industry saw a marked improvement in its markets during the final six months of 1983. Domestic consumption was 17.6% higher in the second half of the year, primarily due to a surge in electric power requirements. The sharp increase in demand for electric power during the third and fourth quarters afforded utilities the opportunity to lower stocks that had accumulated to record levels during 1982. Consumer stocks were reduced from 179 Mt (197 million st) at the end of June to 153 Mt (169 million st) by the end of the year. That is the largest inventory drawdown on record during a six-month period without a major coal strike. Despite the huge depletion in inventories, coal production in the second half of 1983 rose 1.3% above output in the second half of 1982. However, because of the disappointing first half, production in 1983 totaled only 712 Mt (785 million st), 6.4% less than the 760 Mt (838 million st) produced in 1982. Demand The extent to which the economic recovery affected coal markets in 1983 varied: • total domestic coal consumption increased 4.2%; • electric utility coal consumption increased 5.3%; • exports declined by about one-fourth; • coal consumption at coke plants declined 9.5%; and • coal consumption in the other industrial sectors increased 2.9%. Domestic coal consumption totaled 667 Mt (737 million st) it 1983, 27 Mt (30 million st) more than 1982. Electric utility consumption increased from 539 M1 (594 million st) in 1982 to 567 M1 (625 million st) in 1983. Coal consumption at coke plants declined from 37 Mt (41 million st) to 34 M1 (37 million st). Residential and commercial use increased 181 kt (200,000 st) - from 7.4 to 7.6 Mt (8.2 to 8.4 million st). Electric Utilities: Electric power generation increased 3.1% in 1983. Demand for electric power increased in all major consumer categories. Residential and commercial use rose 2.7% and 3.3%, respectively. The most striking increase, however, and indicative of the economy's strong upturn, was the increase in industrial electric power use. Industrial power requirements, which declined 9.8% in 1982, rose 4.1% in 1983. The electric utility sector continued to expand its use of coal last year while lowering its requirements of oil and natural gas. In 1983, electric generation from coal increased 5.7%, while genera-

Jan 5, 1984

By Sunil Koppalkar, Guillaume Noel, Ahmed Bouajila, Makni Sami, Claude Gagnon

"Gold gravity recovery circuits utilizing enhanced gravity separators have become an integral part of many of the modern gold processing plants. Thus, efforts to improve the operating efficiency have been a topic of interest for metallurgists for many years. As part of this endeavour, a methodology to estimate the portion of gold in the ore that could be recovered by gravity separation (gravity recoverable gold or GRG) was developed at McGill University. It has been reported in the literature that the gold content estimated with this methodology is the theoretical maximum that is available for gravity recovery that could only be approached but never achieved. A comparison of GRG recovery obtained in the laboratory with the actual recovery in the plant shows that plants recover between one-third to two-thirds of the value predicted by the laboratory test.Research conducted at COREM shows that particle shape transformation during grinding is a major cause of the discrepancy (even though the bleed percent processed, the quality of cyclone classification and the operating conditions of the gravity separator also contribute to the difference). To analyze the gold particle shapes and their deportment, samples were collected from different streams of a grinding-gravity circuit in a gold plant and compared to a concentrate sample from the standard GRG test. A particle characterization methodology based on gold morphology was developed. GRG mapping in a conventional grinding-gravity circuit and the transformation of GRG into non-GRG, as mainly explained by gold particle reshaping, will be discussed. The knowledge gained from the shape analysis will be used to develop shape distributions and partition curves for the classification of shapes.INTRODUCTIONGravity concentration using centrifugal concentrators has gained increasing popularity since the invention of the enhanced gravity concentrators in the nineteen eighties. Among these, the semicontinuous centrifugal gravity concentrators are most commonly used for recovering gold and platinum group minerals (PGM) from grinding circuit streams. The benefits of gold gravity recovery are now well understood and the acceptance by the mining industry is overwhelming. The occurrence of reasonable amounts of gravity recoverable gold (GRG) in an ore prompts gold mills to install gravity circuits. Thus, the increased use of gravity concentration has necessitated a better understanding of the behavior of gold in grinding circuits and of the factors affecting the performance of the gravity concentrator (Laplante et al., 1995). Due to its high density (19.3 g/cm3 when pure) and malleability properties, gold tends to accumulate in circulating streams making it attractive for gravity recovery. The gravity recovery units are typically installed on a bleed stream of the cyclone underflow, mill discharge or cyclone feed."

Jan 1, 2011

By S. D. Viljoen

The use of ceramics to protect equipment subjected to wear in abrasive and corrosive applications has been accepted by most plants as the industry norm. Little is, however, known about alternative special ceramic based products which are available for the protection of plant assets. With careful engineering, impact resistant ceramics can be used in high impact zones using modern ceramic technology. Properly selected and properly installed, ceramics will provide a tough wear resistant lining for protection against abrasion and impact. Basalt, on the other hand, is widely used in coal washing plant process pipes with varying degrees of success. Basalt is normally not used for the lining of bends, ?T? pieces or reducers due to the reduced wear resistance compared to alumina ceramic. The advantage is a much reduced initial capital cost. A patented ceramic composite non-return valve solved an old problem encountered in the operation of medium sumps. The design approach overcomes the lack of functionality of alternative designs and reduces valve wear while preventing medium settlement during plant shutdown periods. Direct bonded ceramic pulley lagging is becoming the industry norm, eliminating most of the problems encountered with conventional pulley lagging systems.

Jan 1, 2010

This paper deals with the application of table flotation to two unusual mineral dressing problems. Both problems involved the removal of interfering minerals at sizes too coarse to normal froth flotation.The first problem was the removal of arsenical minerals from Broken Hill gravity concentrates without further size reduction. Table flotation without grinding of the original concentrates gave almost complete rejection of the arsenic from the concentrates. A typical test result was a reduction of arsenic in jig concentrate from 0.75% arsenic to 0.007% arsenic.The second problem was to develop a method to produce a high grade calcium carbonate concentrate from coastal dune sands containing about 10% silica and about 80% calcium carbonate. The sands were about 30 mesh British Standard Screen (B.S.S.), and for economic and other reasons it was stipulated that the separation be made without grinding. Again, table flotation gave excellent results. A concentrate was produced containing 99.62% acid soluble material, representing a recovery of 98.69% of the calcium carbonate in the feed with a rejection of 96.44% of the silica.The investigations' were carried out at the Kalgoorlie Metallurgical Laboratory, under the Department of Mines...

Jan 1, 1954

By J. Hu, F. Lin, R. Chen, F Peng, S. Yang, W. Yu

"Microseismic monitoring technology has become one of the most effective method of mine ground pressure monitoring after decades of development. But safety assessment of mine ground pressure by using microseismic monitoring is still in the development stage, it needs to be perfected continuously in practice, and choose the optimal assessment indexes and methods. The definitions and physical meanings of wave velocity, b value, and EI-VA value are introduced in this paper. Statistical calculation of the microseismic events in Luomu Mine is finished by using these indexes, then the functions and calculation results of V, b value, and EI-VA value with the variable of time are also given in the paper. The preliminary safety assessment method is established in Luomu Mine, and it has achieved good results in practical application.1.1 Engineering background The Luomu Mine is a super large molybdenum and tungsten production base in China, ore reserves is up to 2 billion tons, first in Asia and third in the world. It begins mining since the 1960. and bases on underground mining until 2002. In order to recover resources more effectively, it began to use opencast mining method and formed a production of 30000t/d in the early 1990. After about 30 years of underground mining, a large mined out spaces was formed under open pit mine, up to area of 1.2 million m2 and volume of 18 million m3, as shown in figure 1. The large number of mined out spaces seriously affects the normal production, mining and handling of mined out spaces are in the high risk. In the past years, several rock mass collapsions happened, and it caused a serious security threat to persons and equipments. According to the distribution characteristics of mined out spaces, Luomu Mine is divided into A, B, C, D and E mining area. The stability of D mining area is studied in this article. D mining area mainly includes 1376,1350,1340,1317 mined out spaces and 1280 deep large mined out area, as shown in figure 2. The mined out spaces of D mining area is extremely complex and high-risk. Therefore, a microseismic monitoring system was built to monitor the stability of D mining area, a large number of valuable datum has been obtained, and it has a striking effect (Cheng & Peng, 2013; Peng et al., 2013)."

Jan 1, 2015

Supplement to Proceedings Number 120, December, 1940. Drawings accompanying paper by T M Carey 'The Surface Plant at the Zinc Corporation Mine, Broken Hill'

Jan 1, 1940

A study of literature on the epidiorite dykes which transgress the Broken Hill lode and its wall rocks reveals a considerable diversity of thought regarding the time of emplacement of such dykes. In this paper it is deduced that the epidiorite dykes were formed at a late stage and were probably post-ore. Detailed mapping, sampling, and correlation of data from over 100 exposures substantiates this deduction. Physical disruption of the epidiorite dykes is indicated and some interaction of the epidiorite and ore at the time of intrusion is inferred.Further petrological study may confirm this.

Jan 1, 1968

By R. F. Favreau, Patrice Favreau

"A blast with explosives creates vibration waves in the zone around the blast.The prediction of the intensity of vibrations is important because people in the cinity demand that the vibrations do not disturb them, and society imposes limits on the vibrations. The U. S. Bureau of Mines (USBM) showed that the easurement of the particle velocity U predicts the risk of damage from vibrations. A currentapproach of blasters to monitor vibrations is to measure them with a seismograph at several distances S, and create a graph of U vs. S and the explosive charge “W” according to the equation U = K / (S / W)N where K and N are constants that depend on the blast method and the nature of the ground over the distance S. Though useful, this equation is empirical, and the results predicted from it are very variable, as shown by figure 1 which indicates that a prediction of U can deviate significantly from the actual value. Moreover, a minimum of two seismograph measurements at two values of S are required to establish the curve. However, here now exists another very convenient method to predict U; it is with the simulator Vibmas, which is based on the fundamental principles of how a blast reates vibrations. This simulator takes into account not only W but rather all the blast parameters, the type of explosive and the properties of the rock. Moreover, to establish the calculation of U as a function of S, only one seismograph measurement is required rather than two as for the USBM method. This last difference is important because it makes it easy to predict U not only as a function of S, but also as a function of the orientation of S. On the site this allows much safer control of the vibrations, and the use of larger explosive charges which reduce excavation costs. The article presents results from a field case at a hydroelectric project in Canada, where the deviation was very moderate. Use of this vibration simulator on the Web is very easy."

Jan 1, 2015

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.   The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber.   With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.   This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By T. Celik, B. Genc, C. Musingwini

"This paper discusses a new methodology for defining and measuring mine planning software utilization in the South African gold mining sector within an evolving data-set framework. An initial data-set showing the mine planning software providers, their corresponding software solutions, as well as the software capabilities and information on the number of licences was collected and compiled in 2012 in an online database for software utilized in the South African mining industry. Details of the database development and implementation were published in the Journal of the Southern African Institute of Mining and Metallurgyin 2013. In 2014 the data-set was updated with additional and new information. Using the 2012 and 2014 timestamps, a methodology for estimating the software utilization was developed. In this methodology, the three variables of commodity, functionality, and time factor were used to define and measure the software utilization in order to ultimately inform decision-making strategies for optimal software utilization. Using six different functionalities, namely Geological Data Management, Geological Modelling and Resource Estimation, Design and Layout, Scheduling, Financial Valuation, and Optimization, utilization in the gold sector was measured. This paper presents the methodology employed for measuring the mine planning software utilization. The methodology is useful for stakeholders reviewing existing software combinations or intending to purchase new software in the near future and who want to estimate the comparative attractiveness of a certain software package. These stakeholders include mining companies, consulting companies, educational institutions, and software providers. The work presented in this paper is part of a PhD research study in the School of Mining Engineering at the University of the Witwatersrand."

Jan 1, 2015

By O. H. Metzger

This is one of a series of papers being published by the Bureau of Mines on mining areas and districts in the Western states. It describes mining and milling practices in the vicinity of Wickenburg in Maricopa and Yavapai Counties, Ariz. ACKNOWLEDGMENTS The author acknowledges the aid and cooperation of the operators of the mines visited. Reports of geologists and engineers who previously visited the area were drawn upon freely. Individual acknowledgments are made in the text.

Jan 1, 1938

By O?Connor. D. F.

The ever increasing energy costs associated with mining at depth has become an important issue that needs to be addressed for future sustainable production. Vale Inco Limited?s Creighton Mine being the deepest has the highest energy cost per ton due to the ventilation system requirements. A review of the ventilation systems was undertaken with respect to current practices and identification of opportunities to the practical application of technology that would facilitate energy savings. Energy conservation initiatives such as time of day controls have been implemented; however there still remained some opportunity for further reduction. Based on previous studies that identified opportunities due to actual time spent in the workplace, our mining method and ventilation design, it was determined that Ventilation on Demand (VOD) could provide further additional energy reductions with respect to our auxiliary fans. A pilot project has recently been initiated to apply a Ventilation on Demand concept to two 112 kW auxiliary fans and their related workings located on the 2340m level of Creighton Mine. The project objective is to determine the practical methodology and application of this technology in the field. This project involves the installation of variable frequency drive (VFD) starters on the auxiliary fans to allow variable volume (through speed control) based on demand. The required flow is determined based on equipment and/or personnel via identification tags. The Fans adjust to the flow requirements as measured by flow sensors. Since the fans are sized for the final requirements the required flows can be achieved regardless of system length. Energy savings are realized by supplying only the volumes (power) as required and only when required. This paper discusses the rational and program being tested at the VALE Inco Limited, Creighton Mine.

Jan 1, 2009

By Graeme McWhirter

This paper discusses the Installation of a Vibwall for the Cardiff Bay Barrage Project Wales, UK, by Kvaerner Cementation Foundations. Only the second use of the technique in the UK the wall was successfully placed to a depth in excess of 20 metres, in unique and challenging conditions. The installation of the Vibwall was a technical success, but not a financial one. The use of the technique was at its "limits" and this paper recommends some of the controls essential in the carrying out of such work in the future.

Jan 1, 2000

By Trevor Yeomans, David Yaschyshyn

"Placer Dome (CLA) operates the 90-year-old Dome Mine, in South Porcupine, Ontario.The milling operation currently processes 5 million tons of ore per year, from both the underground and Open pit mining operations, producing 320 000 ounces. The milling process is conventional crushing and grinding, with gold recovery by gravity followed by leach/CIP.Cyanide tailings are impounded in a large (325 ha) tailings area where cyanide is allowed to degrade naturally. Effluent is discharged seasonally during the summer and early fall months to maintain site water balance. Pond water is reclaimed for sole use within the mill process.In 1995, an Effluent Treatment Plant (ETP) was constructed for the purpose of removing dissolved metals and suspended solids. In 1997, an INCO S02/Air cyanide destruction module was added.During this time period, the treated effluent often failed toxicity tests required by the Ontario MISA Regulation, even though effluent chemical parameters were below permit limits. Two studies identified ammonia as the toxicant to Rainbow Trout, and free copper as the toxicant to Daphnia magna.From a literature study, and contacts within the Ontario Mining Association, the use of chelation as a final end of pipe treatment step to render any remaining free copper and metal fractions biologically unavailable was considered. Lab and plant scale tests followed.During the 1999 ETP operating season, the addition of the chelant EDTA (ethylene-diamine-tetraacetic-acid) commenced. To date discharged effluent has passed all toxicity tests.The paper will review the effluent treatment history, current effluent treatment plant operation, and detail the use of EDTA for successful toxicity control.History of Tailings Deposition, and Effluent Treatment From 1910 to 1995Over it’s ninety years of operation, the Dome Mine milling circuit has changed from the original 1910 stamp-mill mercury plant, to today’s modem 14 000 ton per day automated gravity and Carbon in Pulp based plant.By the 19803, a modern mill was operating on mainly underground mined ore. The plant was operating at some 3 800 tons per day, using fairly conventional processing routes.The number 4 tailings dam was being used for tailing’s deposition.All effluent treatment was by natural degradation of cyanide. Discharge was from decanting type structures during the summer months only, maximizing the use of natural degradation no tailings effluent was recycled for Mill use."

Jan 1, 2001

By H. Tomlinson

"INTR0DUCTIONThis publication is a third of a series devoted to falls of roof and coal in coal mines of the Western States. It gives the results of examinations of the mines of the Rock Springs coal District of Sweetwater County, Wyo., which represent the principal coal beds therein and approximately 75 percent of total production of the State.A study was made of safety conditions at all the producing mines of the district and suggestions were offered the operators regarding methods and practices which would, in the opinion of the writer, provide additional safeguards to prevent accidents from falls of roof and coal.In presenting the subject, consideration must be given to such features as character of the coal beds, depth of cover. methods of mining, timbering practice, roof testing and supervision, and for comparative purposes to certain statistical matter bearing upon relation of accidents to their causes, tonnage produced, men employed, days worked, and lost days due to accidents during the 3—year period covered by this study.ACKNOWLEDGMENTSThe writer acknowledges the cooperation of the officials of the various coal companies, without whose assistance this work could not have been completed.F0UR REPRESENTATIVE COAL OPERATIONSThis report relates to four representative coal operations in the Rook Springs district of Sweetwater County, Wyo., which are referred to as mines A, B, C, and D. This group employs yearly an average of 993 men, representing 37 percent of the men in coal mines of the county, and has an average annual production of 1,484,373 tons, representing approximately 44 percent of the coal produced in the county. Figure 1 is a map of the Rook Springs coal district."

May 1, 1933

Simulation and Analysis of Media Behaviour in the Tower Mill by Discrete Element Method for Estimating the Power Draw and Spatial Distribution of Grinding Process The trends to the Tower Mill (TM) for grinding the materials are increased recently due to its unique merits. Among the various considerations of this machine, the main important items are increasing the efficiency of grinding as more as possible while keep the power consumption, manufacturing and maintenance costs as less as possible. Because this grinding process includes a huge numbers of media particles (ball or other shapes) that are interacted with each other and body of the machine, the DEM (Discrete Element Method) way is a very useful and essential step to getting confident evaluations. Because the DEM simulation is a very young scientific field and proper commercial software are very rare and still under modification, at first step, a FORTRAN code is developed for DEM simulation of two laboratory Tower Mill models (KM5 and KD5). The simulation and experimental results matched each other properly. Then one another DEM software was implemented to perform simulation of bigger models (huge numbers of balls), meanwhile could handle the complex 3D geometry data. The simulation and experimental results were compared and analysed in detail for not only laboratory but also for industrial models (KW5, KWD5, KWD50, KW300F, KW700F and KW1500) without any manipulation or compromising of the parameters of simulation. Some numeric data of industrial models are hidden here due to confidential reasons. The relative velocity of balls (ball-ball and ball-TM body), dissipate energy, interacted forces and stresses during the process are the key outputs of DEM simulation for design this machine. Therefore the main important processes in a Tower Mill machine are recognised and consequently some horizons of development of this machine are distinguished.

Sep 13, 2010

By Jacques F. Abrahamse, Kevin A. Bahe, T. Arthur Palm, Gregory E. McCluskey, Stephen L. Bessinger

Introduction Basis For System San Juan Coal Company (SJCC) is a subsidiary of BHP Billiton. Until recently, BHP Billiton operated three surface mines in northwestern New Mexico: Navajo, San Juan, and La Plata. The San Juan and La Plata Mines supplied the San Juan Generating Station operated by Public Service of New Mexico. Stripping ratios at those operations were increasing, and by 2000 a feasibility study was underway to develop SJCC’s vast underground reserves as a replacement. Early in the evaluation and planning phase for the San Juan Underground Mine, it was determined that the target seams (Fruitland #8 and #9) had a high propensity for spontaneous combustion. Spontaneous combustion was identified as a risk, both to personnel and equipment, and to the ability of SJCC to reliably fulfill its obligation to the power plant. In the last 20 years, several western US coal mines suffered underground spontaneous combustion events and/or mine fires. Included in this group were Colorado Westmoreland’s Orchard Valley Mine (1987), RAG’s Willow Creek Mine (1998 and 2000), Oxbow’s Sanborn Creek Mine (1999), the West Elk Mine of Arch Coal (2000), Arch’s Skyline Mine (2002), Western Fuels’ Deserado Mine (1996), and the West Ridge Mine of Andalex Resources (2003). The cause for the majority of these fires was spontaneous combustion. Fighting the fires required injection of an inert gas or foam. Nitrogen and carbon dioxide were the predominant choices of inert gas. In all cases, the gasses had to be trucked in from considerable distances. Before the inert gas could be used, injection holes had to be drilled into or near the suspected fire locations. This drilling and trucking caused costly delays in the timing of the fire fighting effort, and was not as precise as desirable. Emergency purchasing of gas and pumping services was extremely expensive, running as high as $70,000 per day at one mine. As a result of the experience of other western US coal operators, and the risk inherent with spontaneous combustion at SJCC, it was decided to pursue installation of a nitrogen delivery facility on-site at SJCC. This decision was later expanded to include a continuous supply of nitrogen.

Jan 1, 2005

Solvent extraction has recently been introduced into Australian hydrometallurgical practice for the production of a high grade uranium concentrate from El Sherana ore by a sulphuric acid leach and solvent extraction process. The solvent is a 5 per cent solution of tri(iso-octyl)amine in kerosene modified with 4 per cent of a long chain alcohol. The stripping reagent is a molar solution of sodium chloride.Preliminary testing for the development of the process showed that the leach liquor was quite amenable to the solvent extraction process and that the equilibrium and rate considerations of both the extraction and stripping steps were very favourable.The industrial plant contains four stages of extraction, three stages of chloride stripping and one stage of secondary carbonate stripping. An internal type of mixer-settler is used for the stagewise contact, the design being based on tests with model equipment.The performance and control of the industrial plant is satisfactory; 99·7 per cent of the uranium is recovered for a loss of 0·3 gallons of kerosene and 0· 4 pounds of amine per 1,000 gallons of liquor treated.INTRODUCTIONThe processing of El Sherana uranium ore from the South Alligator River valley commenced in April, 1959, and thereby introduced into Australian hydrometallurgical practice the unit operation of solvent extraction on an industrial scale. Although there are now some twelve mineral processing plants in the United States and Canada using solvent extraction, its application to the field of primary hydrometallurgy is quite new. Prior to 1956 none of these twelve plants was operating and hydrometallurgical application waslimited to the refining of comparatively high grade uranium compounds and fission products from nitrate and nitric acid solutions.

Jan 1, 1961

By António Fiúza, Anthony Danko, Patrícia Leitão, Aurora Futuro, Cristina Vila, Lurdes Dinis

The average global recovery rates for processing scheelite ores by physical methods are normally in the range 50 to 70%, and it is problematic to attain a minimum grade of 60% WO3 in the concentrates without penalizing further this yield. Direct hydrometallurgical processing of low-grade concentrates or medium- to high-grade ores may become an interesting global economic alternative as it allows increasing the recovery rate, avoiding major penalizations due to the grade of the concentrate and increasing the added value of the final product. Leaching of scheelite by sodium carbonate presents several advantages such as its selectivity regarding the dissolution of troubling metals like iron and aluminium, allowing for a simple and flexible process diagram. However, it has the disadvantage that it is performed at high temperature and pressure with a high consumption of reagents. The feasibility of leaching is appraised by the extraction yield and selectivity, but also by the operating cost. Considering these aspects, a relevant objective of the research was to transform alkaline pressure leaching into a feasible processing alternative directly applicable to both medium- and high-grade ores and simultaneously to low- and high-grade concentrates produced by physical methods. The research used ore samples and low-grade concentrates from a typical skarn orebody as well as high-grade concentrates from a chalcopyrite-scheelite orebody. Different operating conditions were tested. Temperature, pressure and reagent concentration showed to be fundamental, but not exclusive, in determining the leaching behaviour. The operating conditions are milder than the ones generally proposed in the literature or currently in use in industry, but with higher carbonate consumptions. The research was oriented towards potential industrial implementation allowing for the application of optimization methods and straight scale-up to pilot-plan design and project.