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By D. A. Cormode

"INTRODUCTIONPine Point Mines, operated by Cominco Ltd., is located approximately 55 miles east of Hay River, N.W.T. by the southern shore of Great Slave Lake.The milling operation commenced in the fall of 1965 at a design capacity of 5,000 tpd. An addition which came on stream late in 1968 raised the nominal capacity to 8,000 tpd. Currently the milling rate is 11,000 tpd.The lead and zinc sulphides occur in dolomite host rock. Typical feed grades at present are 2% lead, 5.5% zinc and 5 % iron. When dolomite is present even in relatively minor amounts in the zinc concentrate, it presents serious treatment problems and causes inefficient operation of electrolytic zinc refineries.By 1972, it had become apparent that magnesium rejection in the form of dolomite was deteriorating because of increased plant throughput of less amenable ore. This paper will briefly outline the Pine Point zinc flotation circuit and will discuss the two phase program for reducing the magnesium level in the zinc concentrate. The program included changes and alterations to the flotation circuit and the construction of an acid leaching plant."

Jan 1, 1977

By W. G. Johnson

"As we move into 1983, Canada is not only in a deep recession, there are major changes taking place.International competition is growing fiercer.Major core industries such as automobile, steel, mining, oil, agriculture, forestry, fishing, major manufacturing and others are just not expanding.If and when recovery comes starting in mid-1983, as many predict, don't expect industries to suddenly resume former growth patterns. It's just not possible.Companies, by necessity, are becoming lean and mean, and they are still in the process of reducing staff to meet changing times and conditions. Many of the staff now being released may never return to fulltime work with a single employer, particularly if they cannot measure up to more exacting performance standards and management expectations.There are clear cut instances of people who lose a job for reasons beyond their control. A merger, the loss of function, or a major reorganization sometimes creates casualties of people who were excellent performers. Such people can survive well, based on the tongue of good report and with some help from associates or others. However, even good performers often have difficulty in adjusting to the rigors of finding a new job and to become their own personal salesman."

Jan 1, 1983

By P. D. R. Maltby

"1. INTRODUCTIONMy talk today will discuss a new development in the thickening of slurries and clarification of waste water - the Enviro-Clear thickener. Several industrial installations of the thickener have been made in North America in the following applications:1.,water clarification in sugar beet processing plants.2.,separation of pregnant liquors from solid wastes following acid leaching in uranium mills3.,clarification of waste water from coal treatment plants as described in a paper in the June 1975 transactions of the SME entitled ""Application and Utilization of the Enviro Clear Thickener in a U.S. Steel Coal Preparation Plant"" by A.A. Terchnik, D.T. King and J.S. Anderson.2. HISTORYThe application of the Enviro-Clear thickener can be traced back to the filing of U.S. Patent 3523889 in 1970 by the inventor F. Eis. The claims of this patent are shown in Slide 1.The new concept was developed for sugar beet processing by the Spreckels Division of Amstar Corporation, and several such thickeners have subsequently been installed in various sugar beet plants. The Enviro-Clear Co. or New York took over the world-wide manufacturing and marketing of the thickener. Experience in the sugar beet industry indicated that the Enviro-Clear thickener volume requirements could be reduced to as low as one tenth that of a conventional type thickener. Various coal samples were supplied by U.S. Steel Research Laboratories for testing. The tests indicated that feed rate loadings of 3 gpm/ft.2 could be obtained by the Enviro-Clear thickener. Such results led to several industrial applications in the coal industry. Subsequently other branches of the mineral processing industry have come to learn of the possibilities of using this thickener. Slide 2 shows a list of commercial Enviro-Clear installations at the end of 1975."

Jan 1, 1976

By Jason Clarke, André R. Laplante

"The gravity-recoverable gold (GRG) ore characterization test was developed 15 years ago and has been applied to hundreds of ore samples. The test accurately determines the size distribution of GRG, at which grind it is recoverable, and the extent of its liberation above 150 µm. This contribution shows how the test can be simplified, what are the likely problems to occur, and what information is then lost. Two simplified versions of the test are presented, of which the simplest, grinding a 20-kg sample to a P80 of 75 µm, is retained as the best one. A database of 18 comparative tests is presented. The choice of the full GRG test vs. the simple test is discussed, as is the deportment of the GRG recovered in the standard test but not in the simplest test.INTRODUCTIONThe GRG test was developed in 1990 to characterize the progressive liberation of gold in representative samples of ores, with the primary objective of generating data for a gold gravity recovery model (Woodcock and Laplante, 1993; Laplante et al., 2000). Characterization includes the size distribution of GRG as well as the grind size at which it becomes recoverable. This is achieved in a 3-stage protocol of liberation and recovery using a laboratory centrifuge unit, a Laboratory Knelson Concentrator 3 inches in diameter (KC MD3). This protocol is shown in Figure 1. The first stage takes place at a F100 of 850 ?m (F80 of ~550 ?m), the second at F80 of 180 ?m, and the third at a P80 of 75 ?m. The rationale for the three cycles is the desire to preserve the original size distribution of the gold grains in the ore and to obtain a recovery grind size curve. The feed is a representative sample of ore that can be extracted from ore samples (e.g. drill core reject) or stream products of the grinding circuit other than circulating loads or product having undergone hydraulic classification (e.g. rod mill discharge or SAG screen undersize). Ideally the samples should weigh between 60 and 100 kg, depending on feed grade and gold top size. It is beyond the scope of this paper to fully discuss measures of representativity in the ore sample, for example Gy’s minimum sample mass model (Gy, 1979). However, further work in this regard may be an opportunity. The large initial weight facilitates representativity and minimizes weight and sulphide recovery to the concentrate (since concentrate weight is relatively constant at ~100 g), which limits the recovery of gold in nonsulphide gangue or gold carriers (i.e. sulphides). Thus, the 100 g concentrate carries principally discrete gold species, such as electrum, and native gold. The concentrate and a 600-g representative sample of gangue of each stage are screened down to 20 ?m and each size class is fire assayed (the concentrates to extinction, the tails up to 30 g per size class). The five coarsest size fractions of stage-1 concentrate are individually upgraded using a hydrosizer and the concentrates examined with an optical microscope to assess the degree of liberation of the gold phase. Scanning electron microscope work has established that the GRG has an excellent degree of liberation below 150 ?m in stage 1 and generally a good degree of liberation in stages 2 and 3 (Guerney et al., 2003); as a result the size distribution of the GRG has been found to approach closely that of gold grains (Nesset et al. 2005)."

Jan 1, 2006

By A. Demirci, A. Keçeciler, Y. S. Durutürk

"This paper deals with the results of the variation of thermal conductivity of rocks with pressure on a laboratory scale. For this purpose, the authors have added a pressure-supplying unit to the apparatus developed by Mousset-Jones and McPherson (1986), Önder (1995), Ashworth and Ashworth (1979), and Innaurato and Occella (1989) in order to measure the thermal conductivity under pressure. The values obtained from the tests performed by this new apparatus have been stated using a regression analysis and the related graphs have been drawn. Results have shown that the thermal conductivity of rock varies digressively with pressure. The same results have been obtained in different rocks types. IntroductionOne of the most important tasks of mining engineers is that of establishing, maintaining and sustaining safe and healthy working conditions in underground mines.Heat can have a profound effect on safe and healthy working conditions and is one of the main problems in deep underground mines. In this regard, the temperature of the air passing through the mine openings increases steadily and causes a decrease in the efficiency of workers due to the unwanted physical effects to human bodies in the working area. At the same time, the hot and humid environment resulting from heat and temperature rise causes some important occupational diseases and increases the accident risks in the related openings."

Jan 1, 2002

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 M. Kerr, Petra Lampinen, Jinming Zhang, Petra Brodin, C. Hull, Nils-Johan Bolin, R. Asmatulu

"According to Darcy’s equation, the rate of dewatering varies as inverse square of the surface area of the particles to be dewatered and is proportional to the pressure drop across a filter cake. Thus, the difficulty in dewatering fine mineral concentrates can be overcome by using high-pressure filters. When treating ultrafine particles, however, it is often necessary to further dewater the filter cake using a thermal dryer. In the present work, novel dewatering aids that can reduce the pressure requirement have been developed. The reagents are designed to reduce surface tension, increase particle hydrophobicity and increase capillary radius, all at the same time. They were tested for dewatering mineral and coal concentrates in both laboratory and pilot-scale tests. The results show that the use of the novel dewatering aids can substantially reduce cake moistures and, at the same time, increase throughput. In this communication, the case history of using the reagents commercially at the Garpenberg concentrator is given. The use of the novel dewatering aids allowed the operators to use a vacuum filter to obtain desired cake moistures and obviate the need to use a thermal dryer.INTRODUCTIONDewatering is an integral part of mineral and coal processing operations, as it is necessary to remove water from concentrates (or clean coal) to minimize shipping costs, meet contract specifications, and recycle the process water. In general, the cost of dewatering increases with decreasing particle size, which can be attributed to the difficulty in removing the water trapped in the pores (or capillaries) formed between the particles constituting a filter cake.The various parameters affecting the process of dewatering, including the effect of particle size, can be understood in view of Darcy’s equation (Darcy, 1856):"

Jan 1, 2005

By Tony Lipiec, Chris Fleming, Larry Urbanoski

In 2009, the Canadian Mineral Processors (CMP) became aware that Canadian securities regulators were amending the contents of National Instrument 43-101. NI 43-101 is a set of regulations which establish how ore resources and reserves are presented to the investing public. The documents produced under NI 43-101 are central to the ability of many companies to raise financing for their projects. With the increase of metallurgical complexity, and decrease of head grades encountered in new deposits, the role of the Qualified Person (QP) in determining process performance has become increasingly critical in determining the classification category of resources and reserves. Given the challenges confronted by those involved in defining the concentration and extraction of minerals and metals, there is a need to provide support to these QPs. To address these concerns, the CMP established a sub-committee in 2010 to create a set of guideline documents to assist the QP involved in process matters as to what should be included at the various levels of study supporting the establishment of resources and reserves in NI 43- 101. The results of the sub-committee work are presented and the considerations in the writing of the documents are discussed.

Jan 1, 2011

By Norman O. Lotter

The problem of quantifying the full performance potential of an ore body in a concentrator, and how to configure a flowsheet to achieve that potential, either for a new operation or an existing one, is a strategic challenge. Modern flowsheeting technology that has been developed over the last twenty years has provided a suitable platform to achieve this. The integrated use of geology, compositional and quantitative mineralogy, sampling models, quality controls, and mineral processing, including flotation testing, has evolved into what is now called process mineralogy. Two specific tools have been developed and validated as standard methods in this toollbox. These are statistical benchmark surveying and high-confidence flotation testing. Both of these have borrowed from the sampling theories of Pierre Gy and from geostatistics. Additionally, they work on a replicate measurement and averaging basis, thus reducing the overall random error level. With this arrangement, one is in a position to characterize the ore from true samples and identify and quantify the economic minerals present in a manner that easily brings out the processing implications and likely grades and recoveries. In particular, the approach captures the variation in the ore body, which, if properly translated into the flowsheet design, minimizes the risk that unexpected responses will develop in the concentrator operations. A further advantage is that successful plant trials are now possible and practical. An overview of this approach is presented with two case studies.

Jan 1, 2011

By Rodolfo Espinosa Gómez

"Industrias Peñoles, S.A. de C.V. – Mining Division, has initiated in the last ten years, six Mining Operations (Bismark, Tizapa, Ciénega, La Herradura, Rey de Plata, and Francisco I. Madero) and it has expanded several of their existing Operations (Sabinas, Fresnillo, Tizapa, Ciénega) one or more times.This work aims to share the experiences learned on this growing process. Some of these lessons are: 1) Project leaders must have a leadership that fosters good communication and team work; and this leadership style must come from top management. 2) A good communication must exist between the personnel from Engineering, Construction, and Operation. Also, this good communication must come from top management. 3) Starting the project with a solid Engineering Study. 4) Do not misunderstand cost with cost/benefit; always look at the cost/benefit. 5) Selecting good Contractors and good Suppliers. 6) Good training before the project commissioning is essential to reduce the learning curve period, this is even more important in areas where local people do not have any background in mining activities. 7) Recognizing that any project has a learning curve and it must be reflected on the production budget. 8) Avoid an over optimistic Mine preparation time schedule.BACKGROUNDIndustrias Peñoles S.A. de C.V.The mission of Industrias Peñoles, S.A. de C.V. (Peñoles) is to add value to non-renewable natural resources in a sustainable manner. Peñoles seeks to build long-term shareholder value; provide their customers with the highest quality products and services; maintain productive longterm relationship with their suppliers; develop and promote the capabilities of their personnel; foster mutually beneficial relationship with the communities in which it operates, and preserve the environment.Peñoles was established on 1887. It is a Mining Group with integrated Mining, Smelting and Refining operations of non-ferrous metals, and also produces inorganic chemistry materials. Peñoles is the main World producer of refined silver, metal bismuth, and sodium sulphate; Latin American leader in the production of refined gold, lead, and zinc.The Mining Group is made-up of nine mining operations producing concentrates with high gold, silver, lead, zinc, and copper contents. It produced in 2002, 365,900 ounces of gold; 52.7 million ounces of silver; 86,820 tonnes of lead; 266,000 tonnes of zinc, 11,840 tonnes of copper; with a total values of 3,780.6 million of Mexican pesos (~ $ 378.0 million U.S. Dollars)."

Jan 1, 2004

By C. G. Anderson

Industrially proven and applied nitrogen species catalyzed (i.e. NSC) acidic pressure leaching has been utilized to treat a number of ores, concentrates and recycled materials. This versatile technology offers many advantages including low temperatures, low pressures, low capital costs, low operating costs, faster throughput and less costly materials of construction than conventional pressure oxidation. This paper will elucidate the application of this technology for production of gold, silver, palladium, rhodium, zinc, germanium, gallium, cobalt, copper and nickel. Recycled material applications will also be elucidated. In addition, details of an application for treatment of a refractory chalcopyrite copper and gold bearing ore will be presented and pertinent economics discussed.

Jan 1, 2004

By G. Paillard, I. E. Puddington, A. F. Sirianni, F. W. Meadus

Experiments with some selected Nova Scotia coals and a single sample of American anthracite, reconstituted in granular form with lower sulphur and ash contents by spherical agglomeration methods, are described. The effect of different bridging liquids, grinding times, gangue depressents and modes of agitation on the final product are discussed. The application of agglomeration techniques as a means of drying wet coal fines is also noted.

Jan 1, 1968

By Sebastián H. Troncoso

Open pit mine planning is normally based on the selection of an economic envelope that has been generated by the Lerchs & Grossman algorithm, which requires individual economic valuation of each block of a geological block model. The selected envelope, usually called Final Pit, is later discretized in pushbacks and benches, which correspond finally to the fractions that the production schedule will allocate in time. This planning methodology has been widely used by the mining industry in countless projects to exploit open-pit mines, however, in many of the deposits can be found some undesirable elements such as arsenic, phosphates, ash among others that tend to reduce the value of elements of economic interest, either by disrupting the processes of concentration or as deemed impurities that affect the quality of the final product. Thus, a fair amount of blending would be required to capture the real value of the ore body. The traditional approach under estimates a block value by penalizing the block value by the amount of contaminant even when at the mine a set of blocks is amine at a time. This paper proposes a methodology for computing cut off grades over time that would maximize net present value allowing blending that should fulfill a set of metallurgical constraints. Preliminary results show significant increases in value and reserves quantity, questioning the use of fixed cut-off grades in generating a production schedule when blending applies to fulfill a set of geometallurgical constraints. Finally, the model allows the authors to show the importance of having adequate planning tools that will lead to the ability to look at the potential economic value of a mineral deposit.

Oct 1, 2009

By Rob Boom, Yasuyuki Tozaki, Greg Traquair

The objectives of the business case are to examine a proposed metallurgical project and answer fundamental questions about project feasibility, risks, opportunities, and value. A business case fulfills these basic functions: estimates economic value; helps to understand competitiveness; serves as a risk management tool; and serves as a communication tool. A business case evolves with the project life cycle, and supports the gate reviews at the end of each phase of engineering, through to project construction and operations. A business case must be holistic, including all elements of scope that can impinge on project risk and value.

Jan 1, 2015

The problem of thin and very thin coal seam extraction in a long perspective of Ukraine?s fuel and energy industry development was determined. Technical and economic benefits of coal seams selective mining technique including beneficial environmental impact were substantiated. The scientific and practical aspects of development of borehole underground coal gasification (BUCG) technology are considered. The technological scheme of underground gas generators is offered on the basis of the authors? criteria of fitness and adaptability to the mine and geological conditions. These charts foresee the preparation of gas generators from earth surface and directly from the present mine working by inclined horizontal boreholes. Basic research is directed at abandoned supplies extraction in coal mines. Concepts of technological decisions and technical implementation of the underground part of the gasification system are worked out with analytical models, with subsequent test verification on special options and a mine experimental gas generator. Forming the technological scheme of gasification is founded on the basis of tying up spatial and sentinel factosr of coal seam gasification taking into account sufficient impermeability of the system a «gas generator ? rock massif» and to dirigibility by thermochemical processes that flow in a rock massif. The offered solutions contain the possibility of creation of the power and chemical enterprises of gasification, taking into account the complex use of BUCG products in the ecologically reserved technological cycle. Gas generator efficiency is evaluated from an economic standpoint.

Aug 1, 2013

By B. Simser

Noranda?s Brunswick mine is a 10 000 t/d producer of lead-zinc-copper-silver ore that has been in operation since 1964. Mining of this multiple lens deposit is primarily by blasthole stoping techniques between 400 m and 1200 m below surface. The combination of a high overall extraction ratio, an overall steeply dipping tabular shape, and high horizontal stresses (twice the vertical) have elevated the induced stress regime to levels comparable to much deeper operations. Improved mine design, and a better understanding of how the rock mass responds to mining in high-stress environments is essential to improve overall recoveries and maintain safety. Seismic monitoring has proven to be an essential tool at Brunswick, for both short-term safety of workers, and long-term strategic planning. Practical case studies illustrate how seismic data, particularly source parameter information, can be used to measure the rockmass response to mining and improve mining layouts in difficult regions. As the global trend continues toward mining in deeper, higher stress environments (e.g., South African Witswatersrand Basin, Sudbury Basin) and as local extraction and thus ground stresses continue to increase in existing deposits, seismic monitoring will play a critical role in mining safely and economically.

May 1, 2004

By B. Simser, V. Falmagne

"Noranda’s Brunswick mine is a 10 000 t/d producer of lead-zinc-copper-silver ore that has been in operation since 1964. Mining of this multiple lens deposit is primarily by blasthole stoping techniques between 400 m and 1200 m below surface. The combination of a high overall extraction ratio, an overall steeply dipping tabular shape, and high horizontal stresses (twice the vertical) have elevated the induced stress regime to levels comparable to much deeper operations. Improved mine design, and a better understanding of how the rock mass responds to mining in high-stress environments is essential to improve overall recoveries and maintain safety. Seismic monitoring has proven to be an essential tool at Brunswick, for both short-term safety of workers, and long-term strategic planning.Practical case studies illustrate how seismic data, particularly source parameter information, can be used to measure the rockmass response to mining and improve mining layouts in difficult regions. As the global trend continues toward mining in deeper, higher stress environments (e.g., South African Witswatersrand Basin, Sudbury Basin) and as local extraction and thus ground stresses continue to increase in existing deposits, seismic monitoring will play a critical role in mining safely and economically."

Jan 1, 2004

By Jan E. Nesset, Phillip J. Mackey, Joo Y. Kim, Giovanni Di Prisco, André R. Laplante

Understanding the appropriate gold recovery to associate with copper recovery when assessing laboratory testing on porphyry deposits is often complicated by several factors including variable and/or complex mineralogy, and the variability contributed by the low Au content of the various flotation products. As a result, gold recovery is often underestimated and the value contributed by the gold to project economics is less than it should be, a problem that could influence overall project viability. Typically, for these types of deposits, the gold recovery is found to be lower than the copper recovery. In this unique project, having the objective of seeking a better understanding of gold recovery relative to copper recovery, mill feed samples from a selection of six operating world-class Cu-Au low-grade deposits were collected along with the mill metallurgical results for the corresponding sample periods. The samples were subjected to laboratory flotation tests, as well as the Laplante gravity recoverable gold (GRG) test, mineralogical assessment and cyanidation leaching. The aim was to better understand the copper and gold recovery relationship, the links between laboratory and plant flotation performance, the influence of mineralogical differences, and the potential for enhancing gold recovery by gravity recovery techniques. A new correlation of copper and gold recoveries based on the results is presented in the paper. The results showed that the link between copper and gold recoveries established in the best laboratory tests were maintained in the plant results, and further, that the potential for improving Au recovery by gravity or flash flotation methods is directly proportional to the amount of gold greater than 75 microns.

Jan 1, 2005

By I. Nakatsugawa

Chemical conversion coating is a process to create thin oxide/hydroxide film containing several inorganic/organic compounds by way of chemical deposition reaction. In case of the application to Mg mobile electronic housings, the film should possess a good electric conductivity while keeping adequate corrosion resistance and working as a paint base. The use of toxic/hazardous chemicals is strictly prohibited from the environmental aspects. This paper describes the recent trend of conversion coating used for Mg electronic housings and analyzes critically from the point of surface technology. The importance of cleaning process and understanding of surface microstructure are particularly emphasized with several experimental results.

Jan 1, 2006

By T. G. Joseph, K. Barron

A strain-softening constitutive relationship is introduced that describes the post-failure stress-strain curve for rock regardless of whether the rock is intact or broken. The core of this relationship is an “apparent friction” concept that relates the post-failure apparent cohesive and frictional characteristics of the rock to the strain. The relationship can be determined for a given rock via a series of triaxial strength tests establishing the peak strength and corresponding strain for a range of confining pressures, together with the determination of the base angle of friction via a simple tilt test. The postulates and assumptions used in deriving this relationship are verified from results of tri-axial tests on both intact and broken rock. This strain-softening relationship is then applied to coal. Having determined the post-failure stress-strain curve for coal specimens, this information can then be used in a finite element program, such as Phase 2, to examine the post-failure characteristics of coal pillars. Using example data, the strength of coal pillars of different width/height ratios are estimated and compared with well-known empirical pillar size-strength relationships. In addition, the post-failure stress-strain behaviour of a coal pillar is compared with an empirical relationship reported in the literature.

Jan 1, 2003