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By Jim Truskoski, Alain Bouchard, Andy Kerr, Germain Labonté, Jim Barrett

"Improving mill grade recovery relationships is always good business. INCO’s Clarabelle Mill has just undergone a $16 million process upgrade that was designed to improve nickel recovery by 2%. The “Mill Redesign Project” was completed on time, under budget and delivered the promised improvement in recoveries.This paper describes the methodology of the Mill Redesign Team, details of the process improvements and the critical success factors that helped the team deliver on its promises.With a payback of under one year, the Mill Redesign Project will play a key role in ensuring a competitive edge as INCO embarks on its second century of operation.INTRODUCTIONIt is not uncommon in milling operations to encounter a crisis. That is the point when the process does not behave as expected and fails to respond to the increasingly desperate efforts of the metallurgists and operators. Flowsheet and process changes are attempted and abandoned. With luck, one or more of the changes achieves some mitigation of the original problem or more usually, the original cause of the problem disappears. Regardless, the metallurgist can sit back and bask in the apparent success of his or her endeavours.Less common is when a problem is carefully diagnosed, a team put together to explore all avenues and recommend a path of action that is implemented on time, on budget and immediately delivers on the promises which are sustained over time. This is one such story. It is the story of the Mill Redesign Project at INCO’s Clarabelle Mill in Copper Cliff, Ontario.BACKGROUNDThe Clarabelle Mill was built in 1971 on the southern rim of the Sudbury basin. At that time it was one of four mills operated by INCO in the Sudbury area. During the 1970’s, 80’s and 90’s, the need for increased process efficiency, higher levels of sulphur rejection to tails and the concurrent development of high capacity mills and flotation cells, resulted in the consolidation of INCO’s Sudbury area milling operations into a single, expanded facility at Clarabelle."

Jan 1, 2003

By Michel Robert

"In 1974, Copperfields Mining Corporation and Soquem formed a new company, Niobec Inc, to bring the niobium deposit of the St-Honore carbonatite into production.St-Honore is located in the Saguenay area, near the cities of Chicoutimi and Arvida, and about one hundred and forty (140) miles north of Quebec. The discovery of the carbonatite complex was made in the fall of 1967 as a result of an airborne radiometric survey in search of uranium. The detailed exploration of the carbonatite indicated two niobium-bearing formations besides the original discovery of a rare earths zone. During the following years, the niobium formations were defined by diamond drilling and a decline was driven down to obtain adequate samples for metallurgical evaluation. In 1974, after seven hundred (700) bench scale tests, eleven (11) months of pilot plant 2nd a worldwide market research, a joint decision was made to initiate the development of a fifteen hundred (1500) T.P.D. mine and mill, under the management of Teck Corporation. The construction of the facilities were completed in early 1976 both on time and within budget. Niobec is now the only north american and the world second largest producer of Niobium concentrate.The process used at Niobec was developed from the pilot plant programs and later modified by the mill personnel. A simplified flowsheet for this process is shown on the slide. Briefly, run of mine ore is crushed to minus 5/8"" and fed to a rod mill, ball mill, and screens circuit where the ore is ground to 92% passing 65 mesh. The ore is deslimed in two stages of cycloning, and the final cyclone overflow at 85% minus 11 microns goes to waste. The cyclone underflow is conditioned prior to flotation of a carbonate-apatite concentrate. This concentrate is cleaned twice and then pumped to tails. The carbonate rougher and cleaner tails are cycloned in two stages to change the process; water and then sent to the pyrochlore rougher flotation. The rougher concentrate is cleaned five times. This is followed by pyrite flotation to remove sulfur, leaching with hydrochloric acid to remove phosphorus and dyed to less than 0.1% moisture before being sent to packaging."

Jan 1, 1978

By Andrea M. Ouchi

A major focus of ground control research presently being conducted by the Geomechanics Group in the University of British Columbia Mining Engineering Department is to incorporate weak rock masses (RMR76 less than 50) into existing empirical design relationships. An emphasis is being placed upon the updated span design curve/critical span graph originally developed at UBC. The original database has been augmented by mapping of one mine in Montana and of several mines within the Carlin and Getchell Trends of Nevada. In addition, a neural network analysis has been performed and modifications of the span design curves at the lower RMR76 range have been made. The common factor in all the above mentioned mines is a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be dealt with to safely extract the mineral bearing rock. This work attempts to provide rock mechanic tools that will enable a mine operator to make economic decisions that will also ensure a safe working environment.

May 1, 2004

By Elizabeth Gardiner

Tailings and water management facilities are integral components of mine and mill operations. They must be managed for the long term to ensure that safe and environmentally responsible stewardship is achieved. The Mining Association of Canada (MAC) has developed and published two manuals to provide guidance to mining companies on sound practices for the safe and environmentally responsible management of tailings facilities: ???A Guide to the Management of Tailings Facilities; and ???Developing an Operation, Maintenance and Surveillance Manual for Tailings and Water Management Facilities. The Guides were designed to help companies develop and implement tailings management systems that include environmental and safety criteria, to improve the consistency of application of sound engineering and management principles to tailings and water management facilities through their full life cycle, and to demonstrate this to regulators and the public.

May 1, 2003

By Patrick F. R. Murphy

The mechanization of platinum group metal (PGM) underground reef mining in South Africa has posed a challenge to mining engineers for several decades. This is primarily due to the shallow dip angles and narrow thickness (<1.1m) of the tabular orebodies mined, and the issues faced in developing reliable drilling, bolting and loading machines suitable for such hard-rock mining applications. Presently, mining is typically conducted using hand drills and scraper shovels. These methods, however, are intensive in terms of manual labor, and limited in terms of productivity, and improved methods are desired. This paper will review the technical features of a 4 tonne, low-profile, LHD for narrow-reef PGM mining, developed by EJC Loaders Division.

May 1, 2003

By Michel Brissette

"To recover more valuable ore and considering the complexity of minerals, the needs to grind finer is increasing. To reach the desired fine grinding targets, using the existing grinding media size, the energy consumption is increasing exponentially. As already proved at this conference, small grinding media represents the best potential to improve grinding efficiency. How do the small grinding media perform in industrial grinding mills?The use of small grinding media in regrind mills proved that finer grinding can be achieved at lower energy consumption. In ball mills, smaller grinding media versus 25 mm media generate a power saving from 10% to 44%. In vertical stirred mills, the power saving increases from 20% to 60%. More potential savings have been identified.For the same operating conditions, how a vertical stirred mill is performing compared to ball milling? In regrind application, a vertical stirred mill with small media (5-12 mm Millpebs) will require at least 62% less energy than a ball mill charged with 25 mm grinding media.INTRODUCTIONIn some mining applications, fine grinding is needed to liberate further the valuable ore. The purpose of regrind mills is to achieve the last stage of grinding before final flotation stage: the cleaners. In part because of high prices of small grinding media as well as availability, the most widely used size of grinding media is 25 mm.When calculating the recommended ball top size from Bond’s formula (Bond, 1961), the size for regrind applications is much lower than 25 mm. Today, the barrier for small grinding media is broken. They are best suited in regrind application. The size of grinding media is one of the most important variables affecting the mill efficiency (McIvor, R., 1997; Nesset, J.E., Radziszewski, P., Hardie, C. & Leroux, D.P., 2006).Conventional ball milling was discarded for fine grinding because of its very poor energy efficiency (Zheng, J., Harris, C.C. & Somasundaran, P., 1994; Yan, D.S., Freeman, M. & Dunne, R., 1995). Therefore, new technologies as stirred mills were developed to grind finer more effectively. Three fundamental questions should be asked. What is the best fine grinding technology? What should be the best media size to use? Is it possible to grind finer by using less energy with the existing regrind equipment?"

Jan 1, 2009

By R. W. Lawrence

"Biological leaching can be used to enhance the recovery of gold and silver from refractory ores, concentrates and tailings. The method liberates precious metals associated with sulphide minerals such as pyrite and arsenopyrite making them amenable to cyanidation. The chemistry and features of biological preoxidation leaching is discussed. A summary of the results obtained on various ores, concentrates and tailings is presented.INTRODUCTIONRefractory precious metal ores in which gold and silver are finely disseminated in sulphide minerals such as pyrite and arsenopyrite are becoming more important to the mining industry. This is due both to a depletion of simpler, free-milling ores and to a significant increase in the price of gold in recent years. Whereas many ores can be directly cyanided with gold solubilizations over 90% obtained, the refractory ores respond poorly to direct cyanidation and require decomposition of the precious metal-bearing sulphide minerals to increase recoveries.Decomposition of sulphides by oxidation prior to cyanidation can be carried out by several means. The oldest method is roasting which removes unwanted ore constituents by high temperature oxidation and volatilization. In Canada, for example, roasting is used at Giant Yellowknife (Connell and Cross, 1981). Another method gaining increasing acceptance is pressure hydrometallurgy which uses aqueous oxidation conducted at high temperature and pressure. Homestake Mining Company have recently completed construction of a plant incorporating pressure oxidation at their Mclaughlin property in California (Guinivire, 1984)."

Jan 1, 1985

By Claude Bazin

"Laboratory semi-batch flotation tests were conducted using two different sulphide ore samples. The size reduction was adjusted to cover a wide range of flotation feed size distributions. Results show that similar recoveries can be achieved independently of the fineness of grind. This result suggests that possible energy savings could be achieved by a redistribution of the power between the grinding and regrinding mills. The behaviour of the selectivity curves shows that some gangue minerals are more sensitive to particle size than other ones, implying the existence of preferential associations between minerals in the ore.INTRODUCTIONInteractions between grinding and flotation have been studied for many years, and still a robust model to link the two processes lacks to be developed (Girard et al., 2005; Bazin et al., 2001). The ore size reduction liberates mineral grains, while flotation separates them into valuable minerals and gangue. The more size reduction that is applied to the ore the more important is the mineral liberation but also the production of fine particles that can pose problems during flotation (Trahar and Warren, 1976). The definition of the grinding requirement for flotation is a complex problem (Rickelton and Dell, 1977; Sosa Blanca et al., 2000; Morrison, 1993; Wei and Gay, 1999).This paper analyzes the effect of the fineness of grind using semi-batch flotation test results. The first two sections describe the test procedure and the results. The third section analyzes the results in terms of liberation and selectivity, and proposes a possible redistribution of power between grinding and regrinding mills."

Jan 1, 2006

By Douglas M. Smith, G. A. Maki

"The initial development of the massive potash deposits of the prairie evaporite formation took place over a decade ending in 1970. The potash mining and refining facility near Rocanvi11e, Saskatchewan was the 1ast of ten mines to come into production during that era. This operation, known as Sylvite of Canada Ltd., was designed to produce 1. 2 million short tons per year of KCl product in granular, coarse, standard and special standard grades.In 1977 the parent company, Hudson Bay Mining and Smelting, sold the Sylvite property to the Potash Corporation of Saskatchewan. Shortly thereafter PCS slated its new Rocanville Division for a two phase program of expansion. The first phase, completed in the spring of 1979, was relatively small, involving mill debottlenecking and additional equipment in the compaction circuit and the product and ore storage areas. The second phase was a major undertaking which included additional mining equipment and a new 300 STPH milling circuit. This work was completed during the fall of 1981 and has increased the Rocanville Division's nameplate capacity to two million STPY.Thickening equipment operating in the Saskatchewan potash industry is generally situated within the main refinery building or a separate insulated and heated structure due to the harsh winter climate and the need to closely control plant brine temperatures to ensure good flotation circuit performance. Since these thickeners process large volumes of slurries, conventional basin type designs tend to be large, ranging up to 150 feet in diameter or more. As part of the general effort to minimize capital costs, the potash industry has begun investigating the use of alternate high capacity, compact thickener designs. In this regard, PCS Rocanville undertook a program in 1978 to evaluate a Lamella™ Thickener and one other type of 'High Rate' thickener* as alternatives to a conventional design for the phase two expansion project."

Jan 1, 1983

By Joseph L. Fournier

Suncor Oil Sands employs delayed coking technology in converting bitumen into synthetic crude oil. Currently up to 10,000 m3 of delayed coke (coke) is produced per day as a byproduct of the upgrading process, of which up to 9,000 m3 per day is placed in dry storage on Lease 86/17. A review was completed to examine the case history of leachate potential experiments from the dry storage of coke and the environmental relevance of coke leachate studies conducted over the past decade. The review included an evaluation of the potential impacts of environmental conditions within the location of coke storage, including precipitation pH, as well as daily and annual ozone trends. Coke leachate potential has historically been characterized using standard leachate testing protocols (i.e., TLCP, SPLP) together with other studies that have employed strong acids and oxidizing agents in the extraction fluids. The present paper highlights prevailing conditions in the Athabasca Valley air-shed with emphasis given to ambient ozone (oxidizers), as well as precipitation pH and acid input deposition rates, and will demonstrate that TCLP / SPLP tests lack the intended environmental relevance relative to the conditions under which coke is stored.

May 1, 2011

By Augustine O. Orumwense, Micheline Boisclair

"The use of stirred mill to complement tumbling mills in grinding fine grained minerals is increasingly becoming an attractive processing option. Parameters such as agitation speed, grinding media type and size, feed pulp density, and grinding time were studied in order to elucidate their impact on stirred milling. Test results showed that the parameters have a profound effect on stirred mill efficiency and operating cost. A comparative test with a tumbling ball mill was also made and the specific energies of both mills in fine grinding were analyzed. A difference of over 40% in energy savings particularly when the product size is smaller than 20 µm was obtained with the stirred mill.INTRODUCTIONIn industrial processes where very fine and ultrafine particles are required such as in chemical, ink, food, paint and lacquer, pulp and paper, plastics, pharmaceutical, metallurgical and ceramic industries, the use of stirred mills for grinding is well established. Mineral processing plants are gradually shifting focus to the use of stirred mills for fine grinding and /or regrinding purposes as the target liberation size gets very small. A number of plants processing finely/sparsely disseminated ores are known to have adopted stirred milling technology for their fine grinding needs (Enderle et al., 1997; Harbort et al., 1999; Gao et al., 2000; Davey, 2003 & 2006; Pease et al., 2006).There are different kinds/designs of stirred mills available on the market but, all can be divided into two sub groups namely fluidized and non-fluidized types. The non-fluidized stirred mills consist of Tower mill, Vertimill, Sala agitated mill (SAM), and ANI-Metprotech (SVM). These mills are characterized by their low-speed and the use of fairly coarse grinding media size, 3 – 20 mm. Hence, they are mostly suitable for relatively coarse grinding application. The fluidized type includes the Isamill, Netzsch mill and Stirred mill detritor (SMD). These mills have a characteristic high agitator speed, use fine grinding media size of 0.5 – 5 mm, and are employed in very fine grinding operations. The superior fine grinding capability of stirred mills is attributable to two main process parameters, which are the use of fine grinding media and a high mill speed."

Jan 1, 2008

By George A. Lawrence, J. C. McHardy

"Field operating experience with an improved flotation mechanism for handling various flotation applications is covered in this paper. Some aspects of designing flotation machines are also presented. Operating data from extensive testing of commercial size equipment under actual plant operating conditions in the following applications is detailed:1. Copper Flotation2. Fine Coal Flotation3. Base Metal Sulfide FlotationDesign features, design improvements, modifications tested, and overall performance data are reviewed. Some mecl1anical performance data as well as metallurgical performance results are presented. Some comparisons with conventional flotation equipment are reported in this paper.Flotation sizing theories are reviewed and an actual equipment selection ex2.mple is presented. Scale-up criteria used for developing large cells are briefly covered.The paper concludes with a brief review of anticipated future flotation equipment design needs. IntroductionThe mining/milling industry is faced with increasing pressure to cut costs while maintaining product quality and indeed, in some instances, expanding production. For copper, nickel, iron, molybdenum, lead and zinc sulphides, coal, phosphate and some other minerals;, flotation remains the primary method of concentration and recovery of the valuable mineral away from the gangue. Cost reduction in flotation can be broadly focused on two areas:1. Flotation Chemicals2. Flotation Equipment"

Jan 1, 1985

By Stephen R. Grano, Jon Glatthaar, Philippe Steinier, Christopher J. Greet

"The importance of the oxygen content of sulphide mineral pulps in determining which reactions occur, and their subsequent influence on flotation behaviour is grossly underestimated in most operating concentrators. While pH is routinely monitored, Eh and dissolved oxygen measurements are obtained infrequently. However, dissolved oxygen measurements in conjunction with other pulp chemical parameters (i.e. pH, Eh, and EDTA extractable metal ion analysis), can provide valuable insight into where and what type of reactions are occurring within a circuit. Unfortunately, these readings yield “instantaneous” measurements of the pulp chemical parameters.What is needed is a means of establishing how reactive a pulp is, and how this reactivity changes as components of the system are manipulated. Oxygen demand provides an opportunity to do this. Several attempts at measuring the oxygen demand of a pulp have been made in the past with varying degrees of success. Most notable among these are Noranda and BOC Gases.Learning from these experiences, Magotteaux have developed the MagO2 ® demand vessel to measure the oxygen demand of mineral pulps. This paper described the apparatus, and through a case study on Broken Hill lead/zinc ore demonstrates how the MagO2 ® demand vessel is used.INTRODUCTIONThe role of oxygen in flotation is complex. While a considerable body of work exists demonstrating the strong involvement of oxygen in the interactions between sulphide minerals and collector (Gaudin and Finkelstein, 1965; Gaudin, 1974; Woods, 1984; Laajalehto, Nowak and Suoninen, 1993), the presence of oxygen can also affect the oxidation state of sulphide and non-sulphide minerals, which can impact on their flotation behaviour. Further, sulphide mineral oxidation is related to their oxygen demand (Spira and Rosenblum, 1994)."

Jan 1, 2004

By Tanveer Jahir

With increasing energy costs and mounting government pressure to adopt low emission, green sources of energy, it has become imperative to develop long-term sustainable underground infrastructures that exhibit low power consumption. Underground mining environments are mandated to have ventilation systems in place to replace polluted air with clean air. Continuously running air ventilation systems have proven to be an expensive solution for this requirement. Ventilation-on-demand (VOD) is a cost effective method for not only reducing energy consumption and greenhouse gasses, but also ensuring the safety and well-being of the miners beneath the surface. VOD is achieved by monitoring the air quality in target areas of the mine, and based on variables such as the number of personnel in the area, the number of emission-emitting vehicles, the air leakage around doors and entrances, dust levels, and other key environmental details, the speed and angles of the fan blades are adjusted to increase or decrease the volume of air flow. For over 40 years, Conspec Controls has been developing systems capable of VOD through the use of controllers, gas monitors and personnel/vehicle tracking equipment, providing inexpensive, reliable solutions for underground ventilation.

May 1, 2011

By B. Roy

The Somita plant processes low sulphide gold ore in Burkina Faso with a CIL process. After experiencing recurrent low gold recoveries, Somita undertook an investigation on the source of the problem. COREM conducted a mineralogical study on different pit samples. A series of tests was also conducted on a composite sample from the plant which shows a content of 3.4 g/t in gold and 0.48 % in graphite. A reference test in laboratory resulted in a recovery of gold of 75%, similar to plant recoveries for the evaluated ore. In these tests, even if cyanide is not deficient, it was diverted mainly into iron cyanide complex, copper cyanide complexes and by graphite adsorption. Causes of low recovery were also identified and quantified. Solutions to increase gold recovery were suggested such as increasing gold dissolution kinetics by O2 or by lead nitrate addition, change in activated carbon addition point location to the 1st cyanidation tank and finer grinding to increase liberation. Increase in the pH could also contribute to reduce cyanidation consumption. Following these recommendations, Somita changed carbon addition from tank 2 to tank 1 in the CIL circuit. This change led to an increase of more than 5% in gold recovery. A system for the addition of lead nitrate is also under implementation at the plant and benefit will be evaluated in 2013. Finally, pit management for cyanidation will be done based on mineralogy instead of gold content in the future.

Jan 1, 2014

By K. Peake, A. Dalvi, V. Hernandez, S. Chang, M. Oliazadeh

"Ironstone Resources Ltd. is developing the Clear Hills oolitic iron ore deposit in northwest Alberta, Canada. Sources of oolitic iron ore worldwide are abundant and ubiquitous, but there is currently no commercial technology to extract iron from oolitic iron ores. Mineral processing of the ore to generate a commercial iron ore concentrate is very challenging due to the nature of these ores. Accordingly, Hatch and Ironstone are developing a new pyrometallurgical process (Hatch Ironstone Chloride Segregation) to produce metallic iron from high silica and high phosphorus oolitic iron ores. Following the chloride segregation process, the treated ore is subjected to fine grinding. The iron is then separated by magnetic separation. The iron grade and phosphorus content of the final product shows a strong dependence on the separation methodology and the grind size. The pyrometallurgical process has been developed and tested at a lab-scale pilot plant. The commercialization of this technology could provide an opportunity for the development of a new alternate iron making technology. This paper presents the results of test work done on the raw iron ore to create a concentrate and also on the products of the pyrometallurgical process for the production of a high grade 90% metallic iron product.INTRODUCTION Oolite is a sedimentary rock formed from ooids – spherical particles with concentric layers. There are a number of large oolitic iron deposits where the mineralogical form features a low iron content and high concentration of impurities making them presently impossible to exploit on either a technical or economic basis. The fifteen largest oolitic iron ore deposits in the world are estimated to contain approximately 337 billion tonnes of iron ore, which would be a significant source of supply for worldwide steel production. A viable process that can economically recover iron from these oolitic iron ore deposits could become an important new technology to meet future demand in the steel industry. Hatch and Ironstone have demonstrated that oolitic iron ores can be exploited to produce direct reduced iron (DRI). Direct reduction ironmaking is a method for producing solid metallic iron using different techniques compared to the blast furnace process, which is the more conventional ironmaking route. The demand for the construction of direct reduction ironmaking plants has increased in response to the increasing demand for crude steel. It is viewed as a method of providing low-residual iron sources to scrap-based steelmaking in electric arc furnaces."

Jan 1, 2014

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 Marco Lombard, Paulus Kapolo, Christopher J. Greet

"The conversion of a concentrator from one grinding media type to another is a major undertaking in terms of both financial and technical risk. So, a strategy of completing sufficient laboratory and field tests to mitigate this risk, and give the operation confidence that advancing to plant trial will give a high probability for success.The objectives of this paper are twofold: to provide the reader with a strategy for mitigating risk prior to undertaking a plant trial; and to provide a statistical basis for analysing plant trial data. That is, when employing an electrochemically inert grinding media in the primary grinding circuit it is possible to change the pulp chemistry of the system and improve the metallurgical response of the ore.This paper tracks the changes in pulp chemistry and metallurgical performance of Rosh Pinah Zinc Corporation’s silver/lead/zinc concentrator as the primary ball mill was converted from forged steel grinding media to high chrome grinding media. The changed in metallurgical performance are correlated to the shift in pulp chemistry.INTRODUCTIONTheoryBruckard et al (2011) recently published an article describe the effect of the grinding environment on the flotation of copper sulphides. While this paper confined its discussion to copper sulphides the arguments presented apply equally to other sulphide mineral systems. Broadly, these studies indicate that most sulphide minerals are more noble than the grinding media used during comminution. Therefore, the sulphide minerals are cathodic with respect to the forged steel grinding media, and the following reactions apply:Cathode (sulphide mineral): ½O2 + H2O + 2e- ? 2OH- (1)Anode (grinding media): Fe ? Fe2+ + 2e- (2)A galvanic couple between the grinding media and the sulphide mineral(s) exists, which increases the corrosion rate of the forged steel media. The corrosion products of the grinding media, iron oxy-hydroxide species, invariably precipitate on to the surfaces of the sulphide minerals thereby affecting their floatability (Johnson, 2002).The application of more electrochemically inert grinding media to “real” ore systems at an industrial level to improve metallurgical performance has not gained universal acceptance. The aim of this paper is to provide a protocol for conducting laboratory and plant test work that clearly demonstrate that metallurgical benefits are not only possible, but measureable, by way of example. In this case, the work conducted at Rosh Pinah Zinc Corporation in Namibia is described."

Jan 1, 2013

By P. Wells, P. Quinn

"A moveable flotation miniplant was designed and constructed at the research laboratory of Inco Technical Services Ltd. to address the need for flowsheet development with a limited amount of ore (such as drill cores). It consists of one rod mill, two regrind ball mills, one vibratory screen, 24 flotation cells of various sizes and two Venturi aerated flotation columns. The setup has continuous monitoring capability for pH, dissolved oxygen, oxidation-reduction potential, conductivity and temperature in conditioning tanks and flotation cells. Various options regarding flotation reagents, circuit configurations, and fineness of primary grind and regrind can be readily evaluated. The throughput of the miniplant is 20 – 30 kg/hour ore.Unit operations such as flash flotation, magnetic separation and gravity concentration can also be evaluated as an integral part of an entire flowsheet development.This communication describes the basic design features of the miniplant and some examples of applications are given.INTRODUCTIONInco operates numerous mines in Sudbury and Thompson and will shortly bring the Voisey’s Bay mine into production. It has long been recognized that the ores from different mines or from different depths of the same mine can give different responses in flotation. There is a growing need to properly evaluate the ores before feeding the mill to maximize the return of the mine/mill operation. Inco Technical Services Limited at Sheridan Park, Mississauga, Ontario has developed a batch laboratory procedure to address this issue. The results are considered in the overall economical assessment of new mine operations.For ores that cannot be processed by the existing mill operations or that will be processed by a new mill, it is necessary to develop a flowsheet that can maximize the economical return of the mine/mill operation. While recognizing the importance and contribution of the laboratory batch flotation procedure, it does not generate reliable data for flowsheet simulation and design. A full-scale pilot plant campaign is normally required to obtain the design data but often this is not possible due to a limited amount of ore obtainable from the drill core. A small-scale pilot plant (mini pilot plant or miniplant) capable of processing 20-30 kg/h ore can provide this data prior to a full-scale pilot plant campaign. A miniplant can also be used to optimize the circuit configurations, reagent additions and recycle options of process water before pilot plant work and can be used to test a different flowsheet configuration for an existing mill before re-piping a plant circuit."

Jan 1, 2003

By Sydney C. Mifflen

COAL MINING, with its some 15,000 employees, is directly responsible for the livelihood of one-fifth of the population of the Province of Nova Scotia and indirectly so for that of possibly another fifth. Deposits of coal are known and worked in four counties of the Province, from which is being produced yearly tonnages as noted below: Cumberland County 750,000 tons Piccou County 400,000 tons Inverness County 100,000 tons Cape Breton County 5,250,000 tons TOTAL FOR NOVA SCOTIA 6,500,000 tons Production in Cape Breton county is entirely from the one source, the Sydney coalfield, and not only is this field the most important in respect to output, as is disclosed above, but it is also the largest presently known deposit in the Province and holds the greatest tonnage yet in reserve for future mining. In the light of the above more or less generally known facts, it is trite to remark on the importance of the Sydney coalfield in the internal economy of the Province. On the other hand, not nearly as well-known nor as frankly recognized is its significance in the national life of Canada, for from this field is produced not only 80 per cent of the Nova Scotia coal but over 40 per cent of all coal mined in the Dominion. Another noteworthy comparison can be made from the fact that the Sydney field contributes 22 per cent of all the bituminous coal consumed in Canada, the remainder being made up of 7 per cent mined elsewhere in Nova Scotia, 27 per cent from other parts of Canada (British Columbia and Alberta, principally), while the remaining 44 per cent is imported, practically wholly, from the United States of America.

Jan 1, 1941