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By G. H. Hope, A. R. Maycock

"La Mine Doyon is a gold mining operation located in northwestern Quebec, approximately 35 km east of Rouyn-Noranda and 85 km west of Val d'Or. The mine is jointly owned by Lac Minerals Ltd. and Cambior Inc. with Lac Minerals as the manager. Production statistics as of February 1987 are 6.4 million tonnes milled at an average grade of5.8 g/t Au. Current reserves of9.9 million tonnes at 5. 7 g/ t Au to a depth of400m have been outlined. Indicated reserves below this horizon could considerably increase this reserve.The mine currently consists of two open pit and two underground mine operations, producing approximately 3600 tonnes per day of ore at an average grade of6 g/t. The ore is currently processed at the La Mine Doyon mill at a rate of1400tid and at Lac's East Malartic mill at 1950 t/d. Ore is also processed intermittently at Lac's Les Terrains Auriferes mill and at Noranda's Horne Division.La Mine Doyon is currently in the midst of a program to expand and upgrade the mill at La Mine Doyon. The expansion to 3000 t/day includes the conversion of the existing crushing and grinding circuits to a SAG (semi-autogenous grinding) mill circuit and the existing filter wash plant to a CIP (carbon-in-pulp) recovery plant. The economics of this project are based on reduced operating costs (milling and trucking) and improved recovery due to updated technology. HistoryThe area between Noranda and Val d'Or has a long history of mining activity in both base metals and gold, dating back to the early 1930s. More recently, several new orebodies have been discovered and exploited in the area including La Mine Doyon, Lac's Mine de Bousquet, Dumagami, and the Kiena operation.La Mine Doyon was discovered in the early 1970s, and brought into limited production in late 1979. The mine was started on are reserves of 2.75 million tonnes at 6.2 g/t and was, thus, considered a small, short-term operation. Mining started at an initial rate of 550 tI d with all the ore being shipped to Noranda's Horne smelter as flux. When Lac's East Malartic mill became available for custom milling, Doyon commenced shipping to that facility at a rate of 650 t/d. As a result of some equipment additions and an improved understanding of the ore, the East Malartic mill throughput was gradually increased from 650 t/d to the current rate of 1950 t/d."

Jan 1, 1988

By K. C. Armstrong, A. B. Cron, L. A. Melis

"The Johnny Mountain gold mine in northern British Columbia, owned by skyline Gold Corporation, has been in operation since August 1988. Mill operating difficulties at the start of the operation resulted in a depleted cash flow situation and quick improvements were required to generate a self-sustaining financial basis of operation. In October 1988, Melis Engineering Ltd. was contracted to identify metallurgical difficulties, implement necessary modifications, and undertake mill operations and personnel training in order to achieve production targets.This paper presents the operating difficulties which existed at start-up and describes the methodology used to overcome production problems. Metallurgical testing results are described along with the modifications made to the milling circuit to suit ore metallurgy. Plant changes led to the operation of a simple gravity/flotation circuit to recover gold as bullion and in a copper concentrate. Operation of the originally installed cyanidation circuit was discontinued. This contributed to substantial savings in operating costs and virtually eliminated environmental problems. PROPERRTY LOCATION ANR DESCRIPTIONThe Johnny Mountain mine site is located in northern British Columbia along the Iskuit River about 60 km east of Wrangell, Alaska and 275 km north of Terrace, B. C.. A location map is presented in Figure 1 and a site plan is shown in Figure 2. The complex is located on a mountain plateau about 3, 600 feet above sea level. The plateau is flanked to the north by Johnny Mountain and surrounded on the other sides by steep cliffs."

Jan 1, 1990

By Sami Hindstrom, Travis Orser, John Starkey

"A great deal of effort has been expended in the last 11 years by the authors and others to identify the correct power required to grind ore in a SAG mill, by developing ore hardness variability functions for the ore body to be mined. This paper describes the next step in the SAG design process, which is choosing a SAG mill to accomplish the required specified design performance.At the test work stage, each ore hardness data point is a unique and discreet bit of information that represents the energy required to grind the ore represented by that sample at optimum SAG conditions. When the design criteria are set, it is now considered necessary that the required power draw in the mill chosen be provided at optimum conditions as well.Based on actual 3-ft diameter pilot plant results, we can now show that the grinding efficiency and throughput drop when the optimum load limit is exceeded. Future work is expected to show a similar reduction in efficiency when exceeding optimum speed. Providing specified power by exceeding these optimum conditions is not adequate and leads to a lower cost but underperforming SAG mill.It is possible in some cases to modify a SAG circuit to force it to perform better, but this often takes time, much effort and costly modifications. In most cases the capital spent on a properly sized SAG mill may prevent production losses that would be many times greater over the extended start up period. This is the direct result of choosing the proper SAG mill at the start.INTRODUCTIONThe sequential steps required for the design of any grinding circuit, have changed dramatically in the last seven years. Previously, it was considered necessary to do six foot diameter SAG mill pilot plant tests on representative samples of minus six inch ore (F80), in order to understand design requirements. It can now be shown that this method is costly and not likely to produce the desired result because it is difficult to recover six-inch material from deep within a new mine. The representative nature of the sample is often compromised when the sample is selected."

Jan 1, 2003

By T. Schmidt, J. Merza

"This study considers two lead/zinc/silver orebodies which have historically had a problem with pyrite, pyrrhotite and sphalerite contamination in the lead circuit. The problem was previously addressed with high dosages of sodium cyanide as the primary depressant. However, large amounts of cyanide led to environmental problems in the effluent, especially during winter months. The objective was to reduce cyanide consumption while maintaining or improving overall lead grade and recovery via the reduction of the undesirable sulphides.Extensive laboratory and mill testing was necessary to determine the optimal operating parameters for continuous plant application. Evaluation of data received from this testing has shown that selective addition and optimization of the dosage of Unimax SD100 to specific areas of the flotation and grinding circuits has resulted in improved Pb grade and recovery. Parameters such as pH control, regrind operation, the cyanide/Unimax ratio and sulphide mineral content may also affect the performance of the depressant. Each factor is discussed and optimal operating conditions were determined based on the testing.Results are presented for two case studies. Both indicate that Unimax SD100 improves the lead grade/recovery curve by increasing iron and zinc rejection while reducing cyanide consumption and the resulting environmental concerns. 1. Hart"

Jan 1, 1992

By Iwueze Anaekperechi Rose

The International Labor Organization has declared mandatory adequate provision of safe workplace and safety for all workers in all occupations including the mining sector. Early scientists like Agricola (1559) who studied the health of Miners, found that there are peculiar health problems associated to their work and working environment. This unsafe working condition was one of the major factors that resulted to the Industrial revolution in England and eventually led to the establishment of regulations and laws guiding operations in all workplaces and workers in England and all over the world. Recent studies by Heinrich suggested chains of events of safety issues in the mining sector. Occupational injuries, accidents and ill health have huge social and economic implications on workers, their families and communities. Top mining top issues are respiratory diseases, noise, explosives, ventilation, fire, and explosion. However, one of the principal mechanisms for achieving Occupational Health and Safety (OHS) goals and mapping the future is government regulations of employers. In Nigeria, the situation is not different; mining operations are equally hazardous and have far reaching implications. In 1995 the Ministry for Solid Minerals was established to focus on the development of other categories of mineral products ranging from gold, coal, uranium, and tantalum deposited across the country. Prior to this an Act of Parliament Act Cap 121 of 1946, was in place to regulate amongst other contents mining safety. This was subsequently reviewed following the incidence of Lead poisoning resulting from small scale miners processing gold ore highly contaminated with lead in Zamfara state (northern Nigeria). Hundreds of children died as a result of exposure to lead poisoning, it was clear that the regulations were not sufficient (details to be discussed). However, advances have been achieved in mining engineering since then. A review team was constituted to provide a more stringent law to regulate mining operations in Nigeria. The strategies for mapping the future of OHS in mining engineering will employ amongst others setting and adopting ISO/ILO standards and enforcement; providing technical assistance; and establishing sustainable developmental structures as surveillance and compensation. The management systems approach was also developed as a result of cases of accidents. The accepted international standards guidelines and requirements will be proposed. Furthermore in mapping the future for Mining Engineering, it is suggested that most countries have their own management strategies and legislation to improve safety of workers through greater consistency and efficiency of OHS programs. Some American researchers came up with the Safety Engineering Model. The Australian Mining Council of mineral and petroleum resources after the Catastrophic Maura Disaster developed the National Mine and Safety Framework. In Canada, after the Hillcrest mine disaster in 1914, Allan shaft coal mine catastrophe in 1918, Westray mine explosion in 1992 and other disasters, Occupational Health and Safety Act R.R.O 1990 was sufficiently developed to provide adequate safety conditions and standards. In Nigeria after the disastrous Zamfara lead poisoning, which claimed the lives of hundreds of children due to exposure and lack of appropriate safety measures, stringent measures were developed by the federal ministry of Justice to address and regulate mining process in Nigeria.

Aug 1, 2013

By Derek H. C. Wilton, David T. W. Evans

"Abstract - The Midas Pond gold prospect, central Newfoundland, is hosted by sheared and altered felsic and mafic pyroclastic rocks of the Tulks Hill volcanics, Victoria Lake Group, and has been trenched and tested by 19 diamond-drill holes. Gold values are sporadic, with the best diamond-drill intersection assaying 7.3 g/t over 0.9 m, and the highest grade channel sample containing 14.7 g/t over 1.15 m. Alteration and mineralization are confined to a 200 m wide brittle-ductile shear zone. This shear zone formed in response to regional D1 deformation, and the shear zone fabric parallels the regional S1 foliation. D2 deformation resulted in broad Z-shaped flexuring of the shear zone. The deformation was probably related to the ca. 396 Ma to 420 Ma Salinic Orogeny.Advanced argillic alteration and an extensive halo of Fe-carbonate and pyrite surround the gold mineralization. Alteration minerals include pyrophyllite, paragonite, quartz, plagioclase, chlorite, fluorite, Fe-carbonate, and pyrite. As such, the alteration seems to reflect combined epithermal (argillic) and mesothermal (carbonate) mineralizing environments. The argillic alteration and fluorite represent a regional hydrothermal effect on the felsic volcanic rocks; whereas, the Fe-carbonate and pyrite represent a mesothermal alteration associated with auriferous quartz veins. The Au, which is spatially associated with pyrite, occurs in three structurally-controlled vein sets. These veins are confined to the contact between a highly deformed breccia (the banded mafic tuff) and structurally overlying, altered felsic tuffaceous rocks. The vein sets include: V1 boudinage veins that parallel the shear-zone fabric (C-shear veins), and V2 and V3 extensional fracture veins which are controlled by an S2 fracture cleavage. V1 veins are the earliest and contain the lowest concentrations of Au. V2 and V3 veins are concentrated within the hinges of the D2 flexures.Pb isotope data for galena separates indicate that the Pb in the vein systems was probably of local derivation. Sulfur, C, and O isotope data for mineral separates are similar to data for typical mesothermal lode gold deposits. Fluid inclusion data suggest the presence of at least three hydrothermal fluid types in the region, viz., (1) an early saline fluid which produced the argillic alteration, (2) a CO2-bearing fluid directly related to the auriferous mineralization, and (3) H2O-NaCl fluids which flowed through the Midas Pond shear zone at a lateral distance from the zone of mineralization. The mineralizing fluids are interpreted to have been CO3 -2-rich types which originated through metamorphic dehydration and decarbonation of mixed island-arc and continental crustal rocks. Gold precipitation resulted from the reaction of these fluids with the Fe-rich breccia unit. Pre-existing and simultaneously crystallizing pyrite served as loci for Au precipitation."

Jan 1, 2000

By Arthur M. Whiteside

Discussion of the laws bearing upon the economics of mining in this province at once resolves itself under three headings: (a) The rights and obligations of holders of mineral bearing lands; (b) Taxation of mines; (c) Regulation of methods adopted in financing mining operations. Titles: The law relating to titles is contained in the Mineral Act, Placer Mining Act and Coal Mines Prospecting Act. Origin: Mining laws in force in this province and elsewhere on the continent had their origin in the rule-of-thumb regulations adopted by prospectors themselves, when, far from the centres of civilization and the seats of the courts of justice, they found it necessary, for mutual protection, to fix the conditions of possession by right of location, and to prescribe the duties to be performed in order to enable the individual to maintain his ground against all comers. These regulations have been codified and added to by legislatures, until we find adequate protection and safeguard to property in the laws of this province.

Jan 1, 1924

By A. H. Mumin, A. Prikhodko

"This paper provides an understanding of interpreting and evaluating airborne time domain electromagnetic (TEM) surveys as applied to massive sulfide exploration. Variations in the conductive morphologies of massive sulfide ore systems are discussed, followed by forward modelling exercises examining the derived TEM response to these morphologies and discussion of the subtleties of data interpretation. Deposit morphology in the orientation at formation and the variations occurring due to later deformation are considered. Images of corresponding resistivity–depth models are provided. The combined modelling results provide a low-cost method for initial interpretation and screening of TEM anomalies. RÉSUMÉ Cet article nous permet de mieux comprendre l’interprétation et l’évaluation des levés élec-tromagnétiques aéroportés en domaine temporel (TDEM, de l’anglais time-domain electromagnetic) appliqués à l’exploration du sulfure massif. Y sont débattues les variations au niveau des morphologies conductrices des systèmes de minéralisation du sulfure massif, suivies d’exercices de modélisation prospective qui examinent la réponse dérivée des TDEM à ces morphologies et d’une discussion sur les subtilités de l’interprétation des données. L’étude envisage la morphologie de l’orientation originelle non déformée des gisements ainsi que les variations résultant d’une déformation ultérieure. Des images des modèles correspondants de résistivité-profondeur sont fournies. Les résultats combinés relatifs à la modélisation proposent une méthode peu onéreuse d’interprétation et de contrôle initiaux des anomalies dans les TDEM.INTRODUCTION Electromagnetic geophysical surveys are an indispensable foundation of many mineral exploration programs and can account for as much as half of the predrilling exploration costs. Quantitative mass interpretation of the survey results remains difficult due to the infinite variation of deposit morphologies, their complex physical properties, and the presence of barren conductive materials that can mimic or mask the response of targeted ore. Many modern geophysical investigations that focus on time domain electromagnetic (TEM) data interpretations are devoted to problems with inversion and modelling and their algorithms. Although a few of these investigations have resulted in commercial software products, these require highly qualified and experienced users and usually include geometric assumptions. Furthermore, without the input of known physical properties and geometric constraints, the inversion results are highly ambiguous. A number of case studies document the geophysical responses to known targets in well-defined and diverse geo-electrical environments, providing a high degree of correlation between field obser-vation and the results of the modelling used in this style of investigation (Hone, 1980; Schneider & Emerson, 1980; Tyne, Idnurm, & Malone, 1981; Bishop & Lewis, 1992; Hopgood & Hungerford, 1994; Meju, 2002; Yang & Oldenburg, 2016). The uniqueness of the target/environment parameters and their specific features limits the use logy is poorly understood. The responses are therefore that are devoid of complicating environmental factors (e.g., highly conductive overburden and hostrocks or nonuniform target conductivity) as a first approach to the interpretation process of such case studies as the main reference for interpreting TEM survey responses in areas where the underlying geomodelled from generalized and typical geological models"

Jan 1, 2018

By K. G. Chipman

THE discussion on Dr. Chipman's paper, Mapping by the Topographical Survey, centred mainly on the urgent need for aerial photographic reconnaissance of unmapped portions of the country as an initial phase in the provision of suitable topographical maps for use as a guide in geological mapping, prospecting, exploration, and development work in the areas concerned. This, ir was pointed out, would necessitate an expansion of the topographical work of the Bureau of Topography to keep pace with the photographid work and to meet the demand for maps for use by geologists of the Bureau of Geology and others. A resolution requesting Institute Council to make representations to the proper authorities, urging that aerial photography and topographic map-ping be greatly expanded to meet the pressing needs of the situation, was moved by DR. W. F. JAMES and seconded by MR. L. G. SMITH, and carried unanimously. The full text of the resolution appeared on page 221 of the May BULLETIN. Others who spoke in support of the resolution were MESSRS. E. S. MOORE, L. B. ROCHESTER, F. D. SHEPHERD, and W. J. WRIGHT. Dr. Hansen then presented his paper, Mapping by the Geological Survey, discussion on which is summarized below. MR. FRANK EBBUTT(l) spoke of the very valuable service the Geological Survey bas rendered the mineral industry, and indeed the whole nation, in its century of existence, despite the very inadequate financial support it has received. Now, more than ever before, a strong and expanded Geological Survey is essential if the Industry is to continue to prosper. Our known ore reserves are being depleted very rapidly, and we are finding no new orebodies to take their place. As an aid in prospecting and exploration, and also in the development of orebodies when they have been found, we must have geological maps of the vast sections of the country which at present are unmapped or inadequately mapped. The Institute should make every endeavour to have the Geological Survey strengthened so that such maps may be made available as soon as possible.

Jan 1, 1944

By Seppo Haapamaki

"Since it started production in 1970, Anderson Lake Mine has experienced several radical changes in mining methods as a result of the physical characteristics of the ore zone along with the need for improved productivity. This paper examines the transition from longhole open stoping to mechanized cut-and fill then to vertical crater retreat at Anderson Lake Mine. The reasons for the need to change mining methods is analyzed taking into consideration the impact of such criteria as improved productivity and ground conditions and how these criteria affected the over-all economic viability of the mine. IntroductionAnderson Lake Mine is one of five producing copper mines in the Snow Lake area and is situated approximately 3 km southeast of the townsite of Snow Lake (Fig. I).The mine production rate at Anderson Lake is 700 tpd and all ore is trucked from the mine to the mill located approximately 2.5 km from the mine site . The mine is serviced by a three-compartment shaft sunk to a depth of 3300 ft with level spacings at 175 ft and 150 ft intervals from the 600 ft level to the 3000 ft level. .The shaft was collared in 1965 and, a year later, the hoist and compressors were installed. By 1969, a crusher system had been built and actual production began in 1970. During 1978, production was suspended for the year to allow for 430 ft of shaft deepening."

Jan 1, 1988

By Claude Deveau

"Studies on the performance of Falcon batch type concentrators treating ultrafine tantalum at Tanco have revealed that very fine heavy minerals are concentrated within certain areas of the concentrate bed. This information led to the design of a bowl which would allow entrapped lighter low grade particles to escape while providing more space for heavier particles to be recovered in the bed.Numerous tests were then completed with a modified batch-type and non-fluidized Falcon bowl in which the diameter of the discharge lip was adjusted downward manually in steps. This allowed for the gradual building of a higher grade concentrate bed.This work ultimately led to the design of a new Falcon with an automated continuously variable lip. In April 2005, Tanco commissioned the first Falcon UF600.This paper will discuss laboratory scale results and also plant performance of the Falcon’s UF technology.INTRODUCTIONTantalum Mining Corporation of Canada, also known as Tanco, is a wholly owned subsidiary of Cabot Corporation based in Boston, Mass. Operating since 1969, the underground highly mechanized room and pillar operation produces tantalum, lithium and cesium minerals and is located a 2 hour drive east-northeast of Winnipeg Manitoba, Canada.At Tanco, tantalum is recovered using conventional gravity concentration, enhanced gravity concentration and flotation. This paper will discuss how the need for improved equipment to treat very fine tantalum particles was filled by a machine which was modified to the point of creating a completely new technology.In November 2003, Tanco began the investigation for the potential use of a high g-force smooth walled concentrator for treating ultra fine tantalum produced by its flotation circuit. Until then, the tantalum flotation concentrate had been treated by a circuit which consisted of a Mozley Multi-Gravity Separator 902 (MGS), a Mozley MGS 900 and a Bartles cross belt concentrator. Through QemScan analysis, it was found that the majority of the losses from this circuit were of an extremely fine nature which exceeded the recovery limits of equipment on hand. Mean particle size of the tantalum losses was less than 10 µm."

Jan 1, 2006

By Joseph U. Messenger

A method of applying ammonium hydroxide to a drill stem containing hydrogen sulphide gas and hydro-gen-sulphide-bearing oil and water so as to remove the hydrogen sulphide as ammonium sulphide is de-scribed. It was concluded that the method allowed trips with drill pipe filled with sour fluids to be made more safely, more rapidly, and more economically. INTRODUCTION THE DANGER of poisoning rig crews during drill stem tests of sour wells by exposing them to hydrogen sulphide gas is well known in Canada. Concentrations of hydro-gen sulphide in sour gases range from 0 to 40 volume percent. There have been numerous casualties from hydrogen sulphide exposure during drill stem testing. Some have resulted in permanent injuries; in some cases the injuries have been fatal. For example, in Alberta in 1957 there were four deaths and 100 exposures which required medical treatment. These fatalities and injuries indicate the need for a more effective way of handling hydrogen sulphide in oilfield operations.

Jan 1, 1958

By Dennis Z. F. Mraz

"Because rock salt and pot ash formations contain particles capable of elastic deformation, the material has usually been compared with various rheological models containing elastic elements. Extensive laboratory testing of salt and potash samples resulted in various theoretical conclusions based on conditions quite different from those in a deep mine. It is felt that sufficient data have now been collected from underground measurements and observations to demonstrate the inelastic behaviour of salt masses in a deep mine. The conditions in deep salt strata can be defined as near hydrostatic, because the acting pressures are very high compared to the negligible elastic limit of the salt. The pressure field and creep around the single opening is a function of its shape, size and age. The same factors, together with extraction, determine the behaviour of the mining a rea. The application of the correct analytical method in mine design can significantly improve the excavation techniques and predetermine the long-term behaviour of openings."

Jan 1, 1973

By K. Schrijver, G. Beaudoin

"Four occurrences of galena-cemented sandstones, exposed in the Lower St. Lawrence - Gaspésie area, are described. They constitute a new, insufficiently explored type of deposit in Quebec.One mineralized body, a minor occurrence, is hosted in Lower Devonian rocks deposited in an estuarine, intertidal river channel during a marine regression; major cements are dolomite and sulphides. Another occurrence, a drilled prospect, is hosted in Upper Silurian rocks deposited unconformably on Cambro Ordovician basement during a marine transgression. With galena and quartz as main cementing minerals, it is similar to some well-known, economic sandstone-lead deposits. A third and fourth, a drilled prospect and a minor occurrence, are hosted in Upper Cambrian rocks deposited on continental slopes. In both, sulphides mainly occupy a secondary porosity. The differences between the third and fourth occurrences are: (1) cementing translucent minerals (carbonates and barite in one; chlorite in the other); (2) chronology of final subsurface dissolution (prior and subsequent to sulphide precipitation, respectively); and (3) important fracture porosity only in the barite-bearing deposit.The diversity of the four occurrences, and the unequal geological knowledge of their respective features, prohibit the formulation of uniform guidelines for further exploration.IntroductionThe attention of the mineral exploration community is drawn to four occurrences of galena-cemented sandstones (Fig. 2A) in the Cambrian of the Taconian Orogen and in the Siluro-Devonian basin of the Lower St. Lawrence and Gaspésie area (Fig. 1). In view of the fact that sandstone-lead deposits (Bjerlykke and Sangster, 1981) are, or have been, mined in several countries (e.g . Laisvall in Sweden: see Rickard et al., 1979; Largentiere in France: see Foglierini et al., 1980), the mere presence of occurrences in Quebec indicates that the mineral potential of some parts of the Appalachians requires further evaluation.Exploration for the deposits considered here is essentially restricted to geological methods and drilJing (e.g . Mainguet Suares and Samama, 1969), since the response to geophysical methods is virtually nil, at least in the initial, surficial stage of an exploration program. As the particular disciplines of geology utilized in exploration depend a great deal on the geological setting of a mineral occurrence, the diversity of the Quebec deposits is of prime importance. Therefore, the four occurrences (Fig. I, Table 1) studied by the authors are herein briefly described with emphasis on their stratigraphic and tectonic setting, and on the evolution of pore space and sequential occlusion of pores and fractures. Prior to further research in and around the occurrences, now in progress (e.g. Beaudoin, 1987; Beaudoin et al., 1987), it is hoped that the following outline will be useful to the explorationist."

Jan 1, 1987

By Bernard Jones

LTUG ? A meeting of many mining companies that are using large tires ? Introduction of the mines and size ? Companies go over their usage of tires and performance ? As a group we discuss how the manufactures are doing with supplies and performance (who's running what sizes and manufactures they are using) ? The mine's best practices they use (which ones work for them and which ones don't) ? Where the mines see themselves going in the future ? What type of tire management the mines have in place

May 1, 2009

By M. C. Pietrobon

"A common problem in assessing the applicability of laboratory flotation data is determining how closely conditions during laboratory testing of the ore matches those that occur in a plant. Typical laboratory based investigations do not consider factors such as water quality, pulp temperature and the pulp chemical environment during both grinding and conditioning on laboratory flotation performance. Disregarding these important factors may seriously compromise the validity of conclusions based solely on laboratory experimental results. Furthermore, considering these factors during the flowsheet design stage in the development of new ore resources may reduce financial risk associated with building a new plant. A methodology is described here which embraces these factors in an attempt to bridge the gap between laboratory and plant. The methodology should be considered a vital first step in all laboratory based experimental programs and has implications for fundamental studies on the flotation behaviour of single minerals. This methodology increases the confidence with which findings of laboratory based studies can be transferred to the plant and highlights the effect of variables which may be accessible to manipulation in the plant.Pulp chemical parameters, such as pulp dissolved oxygen demand, pH, Eh, mineral oxidation and solution composition were manipulated in the laboratory by adjusting the duration of gas purging after grinding, the process water input and pulp temperature. A key finding was that matching of the laboratory pulp chemistry to the plant pulp chemistry was dependent upon oxidation after grinding. In turn, mineral oxidation was dependent upon the pH in grinding, water composition and the duration of oxygen purging after grinding. The methodology closely matched the dissolved oxygen demand and surface chemistry of laboratory and plant pulps."

Jan 1, 2002

By Yeonuk Choi, Gus Van Weert

"In regular CIL circuits, activated carbon is used for two purposes: avoiding solid/liquid separation after cyanide leaching, and minimizing gold losses in the tails. The carbon distribution and gold profiles in the successive CIL stages are operating variables, not objectives. When the CIL feed contains a preg robbing constituent however, such as native carbon, there will be competition for gold cyanide and this conflicts with minimizing of losses of gold to CIL tails. This paper examines some of the limitations of activated carbon in CIL circuits handling preg robbing Carlin Trend ores.INTRODUCTION Carbon-In-Leach (CIL) has been a great success treating regular gold ores, but the technology is still challenged by preg robbing feedstocks. Little information is available in the gold milling literature on CIL gold extraction from “free” milling gold ores which are preg robbing, or on autoclave discharge (POX’ed) slurries of double refractory ores. Neither feedstock is readily available for experimentation. No literature reference could be found describing deliberate modifications to CIL operations or CIL circuits due to the presence of two types of carbon: “native” and activated. There is some literature on the gold cyanide adsorption activity of native carbons (Schmitz, Duyvesteyn, Johnson, Enloe & McMullen, 2001). Various tests have been devised to measure this activity, commensurate with CIP and CIL practices (Tretbar, Arehart & Graves). In this paper, the term “native” carbon indicates (severely) preg robbing carbonaceous materials found in gold ores. There is considerable literature on the gold cyanide adsorption activity of man-made “activated carbons”. Various tests have been devised to measure this activity, commensurate with CIP and CIL practices. These tests are comparative, i.e. results relate to a standard carbon and depend on the test methodology and carbon history. The test results are equilibrium oriented, hence of limited value to CIL circuit designers or plant operators handling preg robbing solids; in CIL circuits most carbons are not loaded to capacity. Information on gold cyanide adsorption and desorption kinetics might be more relevant and that is one subject explored in this paper."

Jan 1, 2012

By Norman O. Lotter, Lori Kormos, Greg J. Wilkie, Peter J. Whittaker, Johannes S. Stickling

"Assessment of opportunities to improve mineral processing performance in existing concentrators and in describing undeveloped orebodies is key to improving the business case of a mining company. This assessment has traditionally been performed using the distinct and separate inputs from Mineral Processing and Mineral Science.More recently, Process Mineralogy has been used to integrate these two disciplines. This trend has been driven by the need to develop and process more challenging ore deposits, and has been assisted by the availability of modern automated instruments. Together with the acquisition of a QemSCAN (Quantitative Evaluation of Materials by Scanning Electron Microscope) from CSIRO in Australia, and with the use of a supporting SEM with EDX / WDX capabilities and an XRD, the development of Process Mineralogy at Falconbridge commenced in 1997.The sampling challenges in presenting a QemSCAN with representative sample material at the polished section level are significant, but have been effectively addressed. The full description of this aspect is beyond the scope of this paper.It is shown that, by use of this approach, the set nature of an orebody can be best exploited with selected flowsheet changes in a concentrator which address the generic characteristics of the orebody. In this way, the flowsheet provides a process that more effectively fits the mineral processing requirements of the ore. This leads to clear and tangible improvements in grade and recovery."

Jan 1, 2002

By Anil K. Beersing

Effective drainage systems are required for reclamation of mine-disturbed areas to control surface water runoff and avoid excessive erosion. For the conventional structural design approach, armouring material necessary to satisfy the design criteria should not move during the design flood event since displacement would uncover the erodible underlying materials. This paper discusses an alternative geomorphic approach for designing drainage channels and watershed landscape. The approach is based on quantitative studies of geomorphic processes operating in a watershed. A design based on the geomorphic approach replicates the configuration, channel regime, sediment volume and hydrology of natural and mature drainage systems. Movement of some armouring material is acceptable in such an approach because the channels are allowed to mature by natural degradation and aggradation, with erosion rates comparable to the natural environment. The key advantages of a geomorphic approach over a purely structural approach include reduced sizes of armouring material, geomorphologically sustainable landscapes, ?walk-away? or maintenance-free design and reduced liability in the future. The geomorphic approach is illustrated using the example of a coal mining operation in northwest U.S.A. The paper discusses field data collection, design criteria, typical design details, and construction methods.

Apr 1, 2005

By Claude Deveau

"With ever decreasing feed grades, finer mineralogy and increased demand for product, it became obvious that a major step in equipment performance was required to reduce operating costs and increase production. Offsite testwork indicated that a Centrifugal separator was capable of recovering fine tantalum and that the newly developed C Series Falcon concentrator would be capable of replacing many pieces of aging equipment and provide improved performance. Further investigation led to the rental and the purchase of a Falcon C20 concentrator followed by a C10 to maximize circuit performance.Falcon Concentrators Inc’ s practice of working with the customer mirrors Tantalum Mining Corporation of Canada’s (Tanco) philosophy of continuous product development. This synergy honed valve design for continuous operation in a highly abrasive ore environment.Tanco has recently purchased two more Falcon concentrators for the recovery of additional tantalum from its spodumene circuit. These new units have additional user friendly operating features partially based on developments made at Tanco.The Falcon C Series units have enabled Tanco to maximize recovery of tantalum that was otherwise lost while using the original conventional gravity circuit."

Jan 1, 2000