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By Filipe Beretta

This study investigates geophysical logging capacity to predict coal quality. It was analyzed for possible correlation, some parameters determined via laboratory analysis of coal against results for the same parameter derived from wireline logs recorded by a geophysical probe. These probes detect variations in some rock physical properties, such as their natural gamma ray emissions and electrical resistivity. Results showed a strong correlation between natural gamma and ash content, establishing a linear model to estimate ash content from geophysical logging data with a low estimation error (less than 5%). Besides, results showed that there is no correlation between sulphur content or volatile matter and resistivity, neither with natural gamma of the rocks. Ash content derived from gamma ray values can be used as secondary information to evaluate coal quality during resources estimation, using methods such as soft indicator kriging. The methodology is illustrated using a case study at a coal deposit in south of Brazil.

Oct 1, 2009

By Fernando Romero Lage

The purpose of this paper is to analyze detailed crushing and screening configurations and the interrelationship as they relate to mass flow balance, operating efficiency, plant availability and final production. The entropy of ore bodies limits the standardization of crushing and screening plants, however, consideration for a continuous and sensible assessment of the mass flow balance of the circuit will yield the best achievable results. Since energy costs have continuously risen in the last few years, it is imperative that these circuits offer low power requirements and low operating expenses. The paper will detail how the efficient implementation of continuous mass flow balance in the application of crushing and screening plants will generate quality improvement and process improvement, which will translate into bigger production and energy savings.

May 1, 2010

By P. A. Riveros, W. D. Gould, R. Molnar, D. W. Koren, P. Bédard

This paper reports the results of the field demonstration campaign of a new process for removing and destroying ammonia from mining/ metallurgical effluent solutions. The 50-day campaign was carried out at a uranium plant in Saskatchewan, Canada. The process was developed by adapting and integrating two well established technologies: zeolite adsorption/ elution to extract the ammonia from the effluent stream and to produce a concentrated ammonia eluate; and conversion of the ammonia in the eluate to innocuous nitrogen by applying bacterial nitrification-denitrification (NH3 = > NO3 - => N2). The data show that reasonable target criteria were met, under very challenging operating conditions. Problem areas and possible causes for poor performance are identified. Preliminary and generic cost estimates of the process are also presented.

Jan 1, 2003

By Luis A. Tondo

The Paracatu Expansion Project III in Brazil was implemented between 2006 and 2008 to increase the existing capacity from 20 to 61 Million tons per year of gold ore treatment. This expansion led the Brazilian subsidiary of the Canadian Kinross Gold Corporation to become the single largest gold producer in Brazil and the largest single gold concentrator in the world, with a nominal capacity to treat around 167,000 tons per day of ore. This paper describes the Project Development areas for the Paracatu Expansion, using the approach proposed by the Project Management Institute (PMI) and the methodology included in the PMBOK (Project Management Book of Knowledge). The author has more than 20 years of experience in the gold mining industry, having worked as a plant metallurgist, mill superintendent and development manager for RPM until he took the position as the Project Manager of the Paracatu Expansion III in 2005. Luis Tondo has a BSc in Mining Engineering from UFRGS-Brazil, an MScEng from the University of Queensland - Australia and an MBA degree from FDC-Brazil. Luis is currently based in Santiago-Chile, acting as the Project Director for developing projects in Latin America for the Kinross Gold Corporation.

May 1, 2009

By Peter Mitschke, Friedrich Rosenstock, Heinrich Meiler

"The development of the Centrifugal Mill jointly by Chamber of Mines (Johannesburg) and LURGI GMBH (Frankfurt) had been described by L. Kitschen e.al. during the 14th IMPC at Toronto in October 1982. Further investigations, using a 55 kW semi-industrial mill, installed at LURGI's Research Laboratories, were concentrated on efficiency and wear in grinding.The test results showed, that efficiency increases when increasing the ball load between 60 and 80 % by volume. Furthermore, the efficiency is increased by speeding up the mill, thus increasing the centrifugal force to up to 14 times the force of gravity. Applying these findings to grinding of a Canadian iron ore spiral concentrate, a saving in grinding power of 30 % was experienced, when comparing with ordinary wet ball milling.Investigations of several shapes of the grinding chamber cross section and linings and several types of materials showed, that no increase of liner or ball wear will occur compared to conventional ball mills when choosing suitable lining patterns. 1. DEVELOPMENT OF THE CENTRIPUGAL MILLThe centrifugal mill was developed with the aim of finding a grinding unit that can operate at a higher power concentration than the conventional tumbling mills.LURGI felt the necessity for such a mill in connection with a hydrometallurgical process developed at the beginning of the seventies, which incorporated an activating grinding step as one of the essential process features. At that time, the Chamber of Mines in Johannesburg was investigating possibilities of underground wet grinding and preconcentration of gold ores aiming at a decrease of mining costs by reducing the quantities, especially for mines operating at depths up to 3600 m, by changing over from rope hoisting to hydraulic transportation systems. After the Chamber of Mines had initiated the development work on its own, in 1974 a cooperation between the two organisations was started."

Jan 1, 1985

By G. Paquet, E. Godin

"Since the mid fifty's, worlwide pellet production capacity has constantly risen (Fig. 1, Ref. 1 l. There was however at that time no real incentive to decrease production costs but only to produce as many pellets as possible. State of things changed with the iron and steel market recession, starting in 1975, and is currently leading producers to improve pellet quality and to reduce fuel and power consumption.At the Port-Cartier pellet plant, the energy needed for the induration of pellets ranks first in overall operating costs. An important step was made when starting admixing coke breeze in 1980. Oil prices justified the use of coke breeze as a direct replacement in terms of dollar/ton, however, while gaining expertise in using solid fuel a significant decrease in energy consumption was observed (Fig. 2, Ref. 2).In 1985, the ""Centre de Recherches minérales"" was commissioned to undertake research work to investigate the effects of further increasing coke addition to the pellet mix. The positive results of that work led to a 1,5% coke addition plant trial during the fall of 1985. Both laboratory and industrial results are discussed in this paper."

Jan 1, 1986

By R. S. Simkus, J. R. Egan

"Changes have recently been applied to the Sullivan Concentrator lead and zinc circuits to treat fine-grained ores which make-up the majority of ore reserves in the mine. Pilot plant test work conducted in 1990-91 indicated that concentrate grades would be substantially improved by reducing the particle size (P,0) of the lead from 38 to 15 µm and the zinc from 45 to 24 µm.Circuit revisions involved installation of major new equipment including: two GUO kilowatt Vertimills for regrinding, a 4 metre diameter column flotation cell and a 4 metre diameter hyperbaric pressure filter for dewatering. Duties of the existing regrind mills were reassigned.IntroductionThe Sullivan ore body is a massive sulphide deposit consisting of fine grained mixtures of sulphides, sometimes inter-banded with country rock and varying widely in their content of lead, zinc, iron and silicates. Principal economic minerals are marmatite and galena. Iron is mainly present as pyrrhotite (85%), and to a lesser extent as pyrite (15%) .The orebody has been actively mined since 1923, with 1992 ore reserves estimated at 15,800,000 tonnes with an average grade of 4. 7% lead and 7. 9% zinc. Current plans call for treatment of 1,600,000 tonnes/year, (7,000 tonnes per operating day), with flotation feed grades of 5.9% lead, 10.1% zinc, and 22.0% iron."

Jan 1, 1994

By D. Kidby, A. Briggs

"Vitrokele ™ is a synthetic adsorbent, using chelating groups on large polystyrene beads, developed in Canada over 7 years ago, and first commercialised in 1985 to recover noxious metals from plating wastes.Pilot plant trials have been performed in Australia and Canada to demonstrate the recovery of cyanide and removal of metal cyanide complexes from gold plant effluent using Vitrokele1 M 912. The pilot plants comprise a simple adsorption train (similar to a CIP circuit) followed by complete elution facilities, so that loaded Vitrokele™ can be stripped and returned to the adsorption circuit.An account of these campaigns is provided, showing the reduction of total CN levels from over 200 ppm to less than 0.5 ppm and Cu levels from approximately 100 ppm to less than 0.3 ppm in treated tailings.Comparisons between pilot plant results and laboratory test data are given and probable future work on the process and its application to the gold mining industry is discussed.INTRODUCTIONThrough millions of years of evolution, life forms have developed specialised molecules with exceptionally high affinity and selectivity for various metals such as iron, cobalt, zinc and copper.In the early 80's professors at the Faculty of Medicine of McGill University engaged in research on the extremely efficient ways that living cells captured trace metals essential for life.As research progressed, it became evident that the special molecules used by biological systems to capture metals could be synthesized to capture selected metals with similar efficiency from water or other solutions.The technology was first commercialised in 1985 to recover noxious metals from plating wastes with compositions applying the special molecules (chelating groups) on vitreous particles (hence Vitrokele™). To date approximately three commercial Vitrokele™ plants have been installed for treating plating waters in Ontario and Quebec."

Jan 1, 1992

By M. Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

Jan 1, 2005

By R. Mckinstry, M. Rantapaa, T. Bolles

"Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the open pit and process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput.Better fragmentation and a subsequent increase in mill throughput were achieved through the use of electronic caps for more precision and flexibility, as well as for allowing extremely fast shots; explosives with a higher velocity of detonation (VOD) to provide for improved shock energy; and improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by 6 tph in 2003 due to the improved fragmentation of the hard ore.Barrick Goldstrike’s D2M initiative includes roaster hard ore (BWI>17), as well as autoclave hard ore (BWI>15). Approximately 6 million tons of D2M material were shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs."

Jan 1, 2005

By D. Berkley

"Economic and environmental constraints drive more and more industrial organizations in using energy management as one of the means for addressing these issues. The recent increase in energy price could even make energy management a matter of “survival” in some cases.Experience shows that energy management is successful when the energy is managed like a resource, i.e. continuously, systematically, and in an organized manner, not like an expense, paying the bills once a month. This requires the development and implementation of an energy management program (EMP).This paper outlines some of the barriers, keys to success, components, and approaches to a successful energy management program, plant- or corporation-wide."

Jan 1, 2005

By Lorrie Fava

Two needs in the mining industry, to enable overall process improvements, are open systems and network connectivity in underground mines. The Pando project, a collaboration between Symboticware, Vale and Xstrata Nickel, and supported by CEMI, addresses these issues, and leverages the solution platform to deliver intelligent applications. An open system is one that uses publicly available standards for its key interfaces. Vendor-neutrality and ease of information flow are two main benefits that result from the use of open systems. By facilitating the interoperability of systems, open systems allow information to be available when and where it is needed for decision support. Network connectivity in underground mines is typically limited, with hotspots in strategically chosen areas that are relatively static. Mobile equipment moving through a mining work cycle experiences intermittent connectivity; in this situation, seamless remote equipment monitoring is impossible. The Pando project establishes an open technology platform, adhering to the IREDES and OPC UA standards. It enables the collection and integration of information generated by mobile equipment? seamlessly while there is a network connection, and as a store-and-forward gateway to manage intermittent connectivity. The platform capabilities are leveraged to support embedded intelligent applications. This open platform, the SymBot, is a rugged hardware and software device. The platform complies with open standards for industrial automation and systems interoperability. The SymBot platform is capable of providing advanced real-time decision support at the device level, and is designed to be remotely configurable. Applications being developed through the Pando project include engine monitoring, a dynamic load weighing system, machine location monitoring and automated activity monitoring including production and maintenance reporting.

Oct 1, 2010

By Jan W. Merks

"The settlements between mines and smelters are based on the mass of metal contained in concentrate lots. The mass of contained metal is a function of the wet mass of a lot, and its moisture content and metal grade while the variance of the mass of contained metal is a function of the same variables and their variances. Uncertainties in the measurement procedure applied to estimate each variable are quantified in terms of precision and bias. The absence of bias and an acceptable degree of precision are the keys to effective risk analysis and loss control.ISO Technical Committee 183-Copper, Lead and Zinc Sulfide Concentrates, has developed standard methods for sampling and weighing, estimating precision and testing for bias, the determination of mass loss on drying, the calculation of the mass of contained metal and its variance, and various analytical methods for major and minor metals. The variance for wet mass is calculated from the precision of the scale while the total variances of moisture and grade are estimated from pairs of interpenetrating primary samples. The variance of contained metal can be calculated either from mine data or from smelter data but the risk associated with the settlement is largely determined by the absence or presence of bias and the variance of differences between exchange assays.ISO/TC 183 does not deal with precision and bias for exchange assays but is developing guidelines to determine realistic splitting limits. Given that the exchange of assays between mines and smelters accounts for a large part of the risk associated with the settlement, precision and bias for exchange assays should be measured and monitored. The need for umpire services can be reduced by applying statistical quality control (SQC).Calibrating static scales, moisture balances and analytical balances, bias testing of sampling methods and sample preparation procedures, estimating the variance of a single variable or the variance of a function that a set of variables defines, and monitoring precision and bias for exchange assays, are the quintessence of metrology, the science of measurement, when applied in mining and metallurgy."

Jan 1, 1995

By Samuel Frimpong

Synthetic fuel is a liquid hydrocarbon fuel synthesized from unconventional resources, such as tar sands, heavy oil, coal, and oil shale. These unconventional resources are immense and will be a major energy source for the 21st Century as the availability of conventional crude oil and natural gas declines. The authors review the available global distributions, production data, research frontiers, and current research organizations involved in tar sands, heavy oil, coal, and oil shale. Tar sands and heavy oil is mainly deposited in Canada, Venezuela, and the United States. Oil shale reserves are found in United States, Jordan, China and Australia. Coal occurs in United States, Russia, China, Canada, and Australia. Major research and development efforts are focused on reserves identification, transportation technologies, production cost modeling, bitumen extraction process improvements, coal liquefaction technologies, elimination of pollutants, greenhouse gases, and safeguarding human health and the environment. This review forms a major source for educating the public about these important energy sources, and the need to develop environmentally sound technologies and policies for their extraction.

May 1, 2007

By Roe-Hoan Yoon

"Industrial flotation columns often suffer from low recoveries and high maintenance requirements because of poorly-designed air spargers. The MicrocelTM bubble generators were developed at Virginia Tech to overcome these problems. In this system, small air bubbles are generated by circulating a portion of the flotation pulp through a set of static in-line mixers. The small bubbles improve flotation kinetics and allow a higher recovery (or capacity) to be achieved. Other advantages of the system include reduced air consumption, plug-free operation and on-line maintenance. This article discusses the advantages of the MicrocelTM bubble generators and presents examples of successful in-plant demonstrations.IntroductionColumn cells are widely accepted in industry for cleaner operations because they are more selective than mechanically-agitated conventional cells. The improved selectivity can be attributed to the use of wash water which minimizes the entrainment of fine gangue particles into the froth product. Columns may also produce higher recoveries if the air sparging system is properly designed and steps are taken to minimize back-mixing. Furthermore, the quiescent conditions afforded by column cells may be beneficial for recovering coarse particles that are readily detached from bubbles under more turbulent conditions. Also, properly-designed columns offer advantages in terms of savings in floor space, reduced operating and capital costs, and simplified circuitry.It is unfortunate, however, that some of the advantages of columns are not fully realized in industrial practice. Some column circuits are unable to achieve their design capacity, while others require extensive maintenance programs. These shortcomings can usually be attributed to deficiencies associated with the design, scale-up and operation of the air-sparging system. In this article, some of the basic problems associated with commercial air sparging systems are discussed and alternatives are suggested."

Jan 1, 1994

By T. G. Joseph

Mines must manage variability from within their operations as well as those imposed upon them by external forces. This paper provides a framework to manage both internal and external variability through the review and adjustment of the mine plan where applicable to minimize lost production and maintain operational safety.

Nov 1, 2011

By R. O. Burt

"Gravity Concentration, the oldest form of Mineral Processing, remains of major importance to the Industry. Current applications of Gravity Concentration are briefly examined.The Paper details one approach to the development of a Gravity Concentration Plant, from laboratory and mineralogical techniques, through Pilot Plant testing, where applicable, to the actual design of the plant.INTRODUCTIONGravity Concentration, once the major method of concentrating minerals has, for much of the twentieth century been regarded, like the dodo bird, as obsolete. However, in more recent years it is enjoying something of a renaissance, and is once again being treated as a useful, economic alternative in the Mineral Processing Engineers' arsenal.An indication of the broad application of gravity concentration is the variety of minerals presently recovered. A list is given in Table 1; this list is not exhaustive."

Jan 1, 1984

By P. A. Selvadurai

This paper presents the results of a research investigation leading to the development of a technique for the measurement of the surface permeability of Indiana Limestone. The tests are conducted on a cuboidal block of the limestone with a flat surface that can be sealed to create a circular aperture through which water influx can take place. Computational results for Darcy flow are used to interpret the results of the experiments. The water entry area can be moved over the surface area of the block to investigate, quite conveniently, the distribution of permeability across the surface of the limestone block sample.

May 1, 2009

By R. E. Michelutti

"The Sudbury area environment became drastically altered commencing in 1871 with lumbering, repeated fires and early open roasting operations from 1887 to 1929. These combined factors had such a pronounced effect that approximately 24 square miles were totally denuded of any vegetation and 87 square miles were semi-barren to somewhat stressed.The two nickel producing companies in the area have reduced the sulphur dioxide emissions considerably over the years. Falconbridge Limited, alone, reduced sulphur dioxide emissions by 77% from 1971 to 1984.These reductions have resulted in improvements to the air, soil, lake and vegetation quality in the Sudbury area.INTRODUCTIONThe Sudbury area environment became drastically altered commencing in the 1870's with lumbering, repeated fires and early open roasting operations from 1888 to 1929. These combined factors had such a pronounced effect on the Sudbury environment that approximately 24 square miles (64 sq. km.) were totally denuded of any vegetation and 87 square miles (225 sq. km.) were semi-barren.Over the years, the Sudbury area environment has improved considerably. This has been due to emission cutbacks by both Inco Metals and Falconbridge Limited, coupled with industry, government and community reclamation programs. Before the improvements are discussed, a better understanding of the historical degradation is required."

Jan 1, 1986

By F. Bélanger, P. A. Fournier

"Modelling and optimization techniques used in the operation of the Detour Lake Mine leach circuit are contrasted to a 1973 review of contemporary techniques used by a major gold producer. The leach circuit at the Detour Lake Mine was modelled using a full factorial Design of Experiment of stirred tank reactor leach tests using circuit feed. Contour plots of extraction were applied in the plant to optimize addition rates of cyanide and the newly-commissioned lead nitrate system. Contour plot sections were used to understand the impact of sulphur in circuit feed at different operating dissolved oxygen concentrations. The 1973 review paper offers insight into industrially-applied modelling and optimization techniques. In particular, a mathematical model of plant data was developed using multilinear stepwise regression analysis. The model was presented using graphical representations available at the time and applied to optimize the rates of cyanide addition. Off-the-shelf software solutions of today allow mineral processors to quickly and easily visualize data, allowing them to re-allocate time and resources spent processing data to generating raw data and extracting actionable information.IntroductionModelling and optimization in mineral processing is the art of reducing reality through judicious use of assumptions to understand a process and leverage this knowledge to engineer practical solutions to metallurgical problems. Data analysis is at the core of this enterprise.While this paper showcases the modelling work done at the Detour Lake Mine (DLM), the primary objective is to pause and reflect on how far the field has progressed since the 1970’s. A snapshot of state-of-the-art gold cyanidation modelling at that time is a review paper of the Anglo American Group’s capabilities (Brittan & van Vuuren, 1973). The objective of this paper is not a play-by-play of the evolution of modelling and optimization since that time. Rather, it is a comparison of the field at two points in time.In 2016, DLM undertook an extensive bench-scale leach circuit modelling program to better understand the impact of cyanide, dissolved oxygen, lead nitrate, grind size, density, and pH on gold cyanidation (Fournier, 2016). Two major capital expenditure projects were anticipated for 2017: improvements to oxygen control and a lead nitrate distribution system. While the lead nitrate system was planned for construction, the design parameters had not yet been selected. Following the development of the model, plant trials were executed to validate aspects of the model and the methodology was expanded to address other plant issues, in particular the effect of talc chlorite and pyrrhotite in leach feed.The variables of the bench-scale study are summarized in Table 1. Dependent variables were varied using a full factorial design of experiment with two repetitions for each test condition, yielding a total of 300 tests. Test order was randomized to eliminate bias from independent variables."

Jan 1, 2018