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By R. Samuels, R. Klimpel

"IntroductionLaboratory and industrial grinding tests have shown that the process of size reduction of metal containing ores can be significantly influenced by chemicals added to the slurry being ground.,The terms grinding aid or grinding additive refer to a substance which, when mixed into the mill contents, causes an increase in the rate of size reduction. The increased rate can be used to grind a higher feed rate to the desired product size or it can be used to produce a finer product size at a fixed rate. Whether the use of a grinding aid is justified in any given situation depends on the cost of the substance versus the improvement of output or product quality obtained with its use.A wide variety of grinding additive mechanisms have been suggested in the general mining literature (1,2,3,4,5,6,7). The prevention of particle agglomeration, slurry cushioning of grinding media impact, grinding media coating, changing the strength of macro porous rocks, and chemical adsorption on flaw surfaces to change bonding forces and surface energy have all been suggested. More recently, some grinding additive work has been carried out (8,9,10,11) which suggests that the use of efficient chemicals to control the fluidity of dense slurries is a viable economic approach to achieve improved grinding rates. These increased grinding rates are achieved with no increase in power to the grinding mills and apparently with no increase in media consumption costs. Unlike much of the previous work with grinding additives, this recent work is accompanied by a rather complete engineering characterization and prediction of performance capability. The chemicals involved were chosen so as to efficiently control the viscosities of slurries under conditions of high shear yet not adversely affecting flotation, flocculation, and other downstream surface chemistry operations."

Jan 1, 1979

By G. H. Babcock, D. A. Knight, V. G. Medina

"Production commenced at the Golden Sunlight Mine in 1983 and at Kidston Gold Mine in 1985. These projects were both constructed under the management of the Placer Dome Inc. (Technical Services) group of Vancouver, B.C.Golden Sunlight uses a conventional rod mill/ball mill grinding circuit while Kidston uses a SAG /ball mill, and later on, SABC circuit. Since the hardness of the ore and the fineness of the primary grind in both mines are about the same, a meaningful cost comparison can be made. The comparison is made on the basis of capital and operating costs.The result of this study indicates that a significant capital cost savings can be achieved in favour of the SAG /ball mill circuit when the ore is amenable to semi-autogenous grinding. With a good maintenance program, the operating cost for the SAG /ball mill circuit could also be lower that the conventional rod mill/ball mill circuit.HISTORYGolden Sunlight MineGolden Sunlight is a 5 530 t/d gold mine located near Whitehall, a small town 60 km east of Butte, Montana. Originally optioned by PDI U.S. in 1958, the development of the property waited until 1981 when economic conditions became favorable for the project to proceed.Semiautogenous grinding tests were conducted during the final stages of the feasibility study. The hard near surface ore was not quite amenable to semi-autogenous grinding. The best result produced from a series of tests using a 1.83 m diameter mill was a semiautogenous work index of 39. This is substantially higher than the 22 Bond work index of the sample used in the testwork. A conventional SAG/ball mill circuit for this ore will be extremely inefficient, and for this reason, this circuit was rejected in favour of a conventional rod mill/ball mill circuit."

Jan 1, 1991

By Steve McAlister, Colin Sprake

"Enhanced gravity concentration machines have been applied successfully in the following areas of precious metal recovery flowsheets:1. Primary Grinding Circuits2. Shaking Table Tailings3. Pre-Concentration of Leach Feed4. Flotation Concentrates -•, Flash•, ConventionalAlthough great progress has been made, the ability to produce directly smeltable concentrates still remains elusive. Even without this ability, centrifugal concentrators are finding wideningapplications in precious metal concentration:1) PRIMARY GRINDING CIRCUITSEnhanced gravity concentration technology has largely replaced jigging as the technology of choice in precious metal grinding circuits worldwide. The benefits of using a centrifugal field to concentrate both coarse and fine gold are well documented but the placement of these machines within grinding circuits is still evolving. Conventional wisdom dictates that the best location for enhanced gravity machines is cyclone underflow on account of the elevated grade found in this stream when compared to cyclone feed or overflow. Plant operating experience at both large and small scale indicates that there are compelling arguments to place ENHANCED GRAVITY MACHINES on cyclone feed instead. At least two new plants, presently in the detailed design stage will incorporate gravity circuits that treat mill discharge or cyclone feed, Teck Cominco’s Pogo and Newcrest’s Telfer Expansion.Current Conventional PracticeThe current stream of choice for enhanced gravity concentration within grinding circuits is cyclone underflow although recent information indicates a swing toward cyclone feed. Here are some of the arguments for treating a portion of cyclone underflow:"

Jan 1, 2003

By S. Bergquist

In this paper, it is investigated how different types of automation would affect the safety for workers in asphalt paving. The risk for the workers on road construction sites is consistently high in comparison to the average risk of the working population. Automation has been suggested as an alternative for improving the safety in roadside construction assuming that removing workers will inherently eliminate the risk of them being injured. In this paper, the potential for improving the safety using automation is analyzed in detail. By investigating accident statistics and understanding the type of accidents that appear, several different automated functions for increased safety are proposed and described. Based on available statistics, it is possible to estimate the safety benefit, as the reduction in fatalities, for several of the proposed functions. The highest safety benefit would be achieved by automating the road traffic driving through the work zones. This has the potential of reducing the total number of road worker fatalities with over 30 %. In addition, it would decrease the number of road traffic accidents in work zones. Automation of construction machinery and dump-trucks also has the potential to increase the safety.

Aug 1, 2013

By D. Komljenovic, J. Paraszczak

"This paper presents the use of queuing theory in truck fleet sizing in open pit mining operations. In the first part, a methodology is developed by which an optimal ratio between the size of shovels and trucks may be determined. The second part gives the fundamentals of the queuing theory and its application in analyzing shovel and trucks. The stochastic character of involved times (loading, truck cycle, etc.) is taken into consideration. Using the above theory, the optimal truck fleet size in actual conditions may be estimated. Minimal operating cost of the working system (shovelstrucks) represents the basic requirement of the analyzed process. The methodology was validated on Caterpillar front-shovel – truck combinations. IntroductionLes camions représentent probablement les équipements les plus utilisés pour le transport dans les mines. Le coût de transport peut parfois atteindre 50 % du coût d’exploitation et 25 % du coût total (Collins, 1996; Kennedy, 1990). Il est critique pour une opération minière de le minimiser. C’est un sujet qui a été traité relativement souvent dans la littérature spécialisée. Les premières applications informatiques dans l’industrie minière ont été développées pour la détermination du temps de cycle des camions.Au fil des ans, la capacité des camions a augmenté et, aujourd’hui, les plus gros manufacturiers de camions (Caterpillar, Orenstein & Koppel, Euclid, Terex, Unit Rig, Komatsu, Liebherr, Belaz) fabriquent des camions ayant une capacité de 200 t et plus dont quelques-uns d’une capacité supérieure à 320 t. Pour les plus gros camions, le coût d’opération peut même dépasser 240 $US/heure dans des conditions modérées (Caterpillar, 1999). Les mines modernes de grande taille peuvent posséder plusieurs dizaines de camions dans leur flotte."

Jan 1, 2004

By Norman A. M Macleod

FOR the past seven years, all flotation at the Britannia mill has been done in Forrester Air-Lift cells. Prior to 1931, the roughing and part of the cleaning operation had been performed in four 21-cell and two 14-cell M.S. machines. The resulting economies in reagent, power, maintenance, and general operating costs, and the increased recovery, more than justified the exclusive use of the Forrester machine. About three years ago, the possibility of still further improving the efficiency of the flotation section was the subject of considerable discussion and experiment. Arising from these experiments, tests were made of the practicability of using a cell of greater depth than that of any pneumatic or mechanically-agitated machine in common use. Cells were constructed with depths of 7 .5 feet, 10 feet, and 15 feet, and, in all cases, a very definite improvement in operation was indicated. The cell now being used in the mill treats from 5,500 to 6,200 tons of dry feed per day. It is 100 ft. long by 5 ft. wide by 8 ft. deep, and has replaced a total length of over 500 feet of standard Forrester machine. The choice of a depth of 8 feet was governed by the type of blower which was available-in this case, a Roots-Connersville blower, driven by a synchronous motor and delivering 6,000 c.f.m. of free air at 4.0 pounds per square inch. At the Chelan Division of the Howe Sound Company, where a new mill was recently built, all flotation is carried on in cells 10 feet deep, with good results.

Jan 1, 1938

By D. Komljenovic

This paper presents the use of queuing theory in truck fleet sizing in open pit mining operations. In the first part, a methodology is developed by which an optimal ratio between the size of shovels and trucks may be determined. The second part gives the fundamentals of the queuing theory and its application in analyzing shovel and trucks. The stochastic character of involved times (loading, truck cycle, etc.) is taken into consideration. Using the above theory, the optimal truck fleet size in actual conditions may be estimated. Minimal operating cost of the working system (shovels-trucks) represents the basic requirement of the analyzed process. The methodology was validated on Caterpillar front-shovel ? truck combinations.

Sep 1, 2004

By Stephen L. Chryssoulis

"""Preg-robbing"" of gold by carbonaceous matter during the cyanidation of certain types of carbonaceous gold ores is well documented. Recent studies established that ""preg-robbing"" of gold is not limited to carbonaceous matter. Gold sorbed on the surface of pyrite grains was detected and quantified by TOF-LIMS (Time of Flight Laser Ionization Mass Spectrometry). Crystallites of pyrite from a number of ores from different geological environments have been shown to have gold on their surface apparently sorbed from the ore forming solutions. Surface gold accounts for significant fractions of the gold head assay. Preg-robbing of gold by pyrite from pregnant cyanide solutions was also documented, and accounts for significant losses to tailings. Preventative measures are discussed.1.0 IntroductionThe detection and subsequent quantification of gold sorbed on the surface of pyrite particulates came about during routine determinations of the deportment of gold employing the comprehensive mineralogical approach (Chryssoulis and Cabri, 1990). In some pyritic gold ores it was discovered that the sum of the various forms in which gold ""conventionally"" occurs, was short of the gold assay. The mineralogical procedure used involves the independent determination of each fraction of gold, in other words there is no form of gold which is calculated ""by difference"". The systematic shortfall after having added the forms of gold listed in Table 1 led to the inquiry for the 'missing' gold and its discovery on the surface of pyrite grains, such as crystal facets and fractured surfaces.Preg-robbing of gold by pyrite from pregnant solutions was first described by Lloyd. In his studies, preg-robbing was measured by changes in the solutions/solids gold assays. This paper describes the first application of a direct measurement method for surface gold on pyrite particles from untreated and processed samples, its impact on gold deportment and processing. The advantage of the direct measurement lies in the absence of interference from other forms of gold, leading to more accurate and precise determinations of this unconventional form of gold."

Jan 1, 1997

By D. M. Doyle

"In this paper I will summarized the Falconbridge Nickel Mines1) energy costs and consumption data by fuel, process, cost centre and estimate our future costs and consumption patterns 2) detail the distribution of electrical energy 3) distribution of other forms of energy 4) describe present and planned energy conservation schemes; and 5) discuss economic justification and responsibility.There is sufficient material in this presentation to warrant several technical papers, however we felt that an overview of all our data and endeavors on the subject, would be most beneficial to those companies formulating energy conservation plans. The data briefly referred to in this slide presentation can be found in the technical paper.Over a five year period, total energy costs will vary between $63 and $94 MM depending on the future rate of energy cost escalation. An unrealistic 32% reduction in energy consumption is required to hold our own in the years ahead whereas an attainable 10°;, reduction in energy consumption would save $9 MM over this five year period.Total energy consumption, tonnage of ore delivered to plants and their ration BTU’s per ton of ore, are graphed for the years 1973 through 1976 and forecasted for the 1980’s. In 1974 we along with other member companies of the Mining Association, determined our purchased energy per ton consumption rate and set, as our goal, a 20% reduction by 1980. The dotted lines calculated from the energy audit, based on 1976 data shows there is a potential for a 10% increase in energy per ton. This could result from a lower than forecasted mining rate and operation of the new roasting, electric furnace and acid recovery facilities installed for environmental considerations at designed capacity."

Jan 1, 1978

By A. Wright, P. Lacombe, R. del Villar, D. Hodouin, C. Sepulveda

"The data acquisition from industrial plants is a fundamental step for process modelling in process optimization, process analysis and automatic control.The introduction, some years ago, of modern distributed control and data acquisition systems in concentrators imposes a new approach in designing experimental schemes for data acquisition campaigns and new criteria for the treatment of the obtained discrete information.This paper presents the methodology applied to sample a zinc flotation circuit at Les Mines Selbaie, Joutel, PQ. Values of 85 process variables were obtained form the Distributed Control and Data Acquisition System (Bailey Network 90) and transferred to the DOS environment. Another 11 variables (flowrates and valve positions) were directly sampled using an IBM-PC compatible computer equipped with a data acquisition card and a signal processing circuit.All variables, under the vector form, were processed in the PC-MATLAB environment to either filter or eliminate the non-linear disturbances and noises, producing useful data for model development. The filtering algorithms are also presented.INTRODUCTIONProcess control does not need to be justified. Whether manual or automatic, any processing plant requires some form of control to accomplish its main objectives: a good quality product and a target throughput. Process control of mineral processing plants has steadily evolved from manual control, where the operator skills and/or experience play an important role, to some level of automatic control, usually considered better, as less human subjectivity is involved, at least when actions have to be taken.The design of these control systems requires the knowledge of the dynamics of the process it is deemed to control. Process modelling is therefore an essential step in the assessment and the design of a control strategy. The choice of model will depend on the available resources and manpower."

Jan 1, 1991

By Earl Sweet

This overview of economic and financial market prospects examines the current and future state of the global and Canadian economies with a focus on commodities. Housing prices and global conflicts all have effects on the overall economy and metal prices and mining developments in particular. This presentation outlines where we are today and where the author and BMO see the economy moving over the next few years.

Jan 1, 2016

By P. G. Claridge, R. A. Tenbergen

"Pipe Open Pit ore is delivered by rail to the Thompson Mill at a rate of 34,000 tons per week. Ore is milled at a rate of 220 tons per hour.Characteristics of the serpentinised peridotite host rock are such that significant deviations from hitherto experienced milling practice became a necessity because of coagulation of the gangue upon cominution.Extensive development work was done in the grinding and classification circuits to better understand the ore characteristics and optimize operating parameters and the use of available equipment. This work ultimately resulted in the change from 30 to 20-inch diameter cyclones.Coagulation of the ore slurry and the characterstics of the sulfide minerals necessitated an ""unconventional approach"" in processing as compared with the beneficiation of Thompson Mine ore.Recent changes in ore characteristics led to testing of antistatic agents to reduce tailing losses."

Jan 1, 1975

By G. A. Kosick, G. S. Dobby, O. Matwijenko

"A 100 kg/hr portable flotation pilot plant has been operated at Kidd Creek Mines with the objectives of:(a) determining performance expected by column flotation circuits on primary zinc and copper cleaning, and (b) evaluating column flotation circuit configurations.The self-supporting pilot plant, owned by Minnovex Technologies Inc. and operated by Minnovex and the University of Toronto, consisted of three 16 cm diameter by 6.5 m high columns and a bank of four Denver No. 7 cells. It was configurable to any arrangement using these four (or fewer) units. The columns were controlled through the use of multiple pressure transducer measurements. This paper presents the approach to testing and the results of more than 70 circuit tests. INTRODUCTIONThe integration and retrofitting of flotation columns within existing mechanical cell flotation circuits is becoming a common occurrence. The correct approach to this integration, however, is often difficult to define, due to a scarcity of previous experience and the difficulty in predicting column circuit performance. In most cases, the effect of column implementation has been experimentally assessed using a single pilot column, with the consequence that selection of an appropriate circuit to implement is difficult. Important considerations are the impact that column water addition will have on the existing operations, and the differences between mechanical cell and column performance in integrated cleaning circuits.To address the problem of circuit selection a portable flotation pilot plant, consisting of both columns and mechanical cells, was designed and constructed by Minnovex Technologies. The pilot plant was structured for complete flexibility of circuit configuration, with the intent to provide a means by which both research and plant personnel could determine the best possible column circuit configuration for a given application."

Jan 1, 1990

By D. R. Lentz, C. J. Beaumont-Smith, S. H. Mcclenaghan

"Abstract - The Louvicourt Au-Ag-Cu-Zn-Pb sulfide deposit is hosted by a Middle Ordovician calc-alkaline sequence of aphyric rhyolite flows and associated fragmental rocks at the top of the Flat Landing Brook Formation. The Zr/TiO2 (average = 0.110) and Y/TiO2 (average = 0.021) ratios in the footwall felsic volcanic rocks are consistent with known values for the Reids Brook member. The deposit consists of two concordant lenses of semi-massive to massive sulfides, approximately 150 m long and up to 9 m thick, which represent a fold repetition of a single exhalative horizon. The deposit contains a geologic resource of 136 000 tonnes grading 1.2% Pb, 1.0% Zn, 0.4% Cu, 90.9 g/t Ag, and 0.96 g/t Au; the deposit locally contains elevated Au (2.9 ppm) and Ag (320 ppm) contents. A laterally continuous iron formation that contains barite caps the deposit, and is gradational vertically and laterally into laminated siltstone. The exhalite confirms the stratiform nature of this deposit, but a large percentage of sulfides occur as late replacements of altered felsic fragmental rocks in the footwall. Abundant examples of colloform pyrite and perlitic and spherulitic textures in volcanic clasts are well preserved. The base- and precious-metal content of the Louvicourt deposit is atypical of the Bathurst Mining Camp (BMC). Reported assay data (n = 27) indicate an average Pb/Zn ratio of 2.6, the highest in the BMC (average = 0.39). Lead exhibits a strong Spearman Rank correlation (r' = 0.92) with base metals throughout the sequence, indicating a preponderance of galena in both the stockwork and stratiform zones. The Ag and Au contents in this deposit are among the highest in the BMC and exhibit a Au-Ag- Cu-Pb association. Barite-rich exhalative pyrite exhibits a moderate Au correlation with Ag (r' = 0.77; n = 10) and Cu (r' = 0.76) and occurs in portions of the exhalative sulfides that are enriched in Pb. Chemical exhalative rocks are conformably overlain by trachy-andesitic volcaniclastic (possibly pyroclastic) rocks that are assigned to the Little River Formation. These are enriched in Nb (average = 38.4 ppm) and P2O5 (average = 0.17 wt.%), and have much lower Zr/TiO2 (average = 0.056) and Y/TiO2 (average = 0.0062) relative to rocks higher in the hanging wall. The intermediate volcanic rocks are conformably overlain by massive to pillowed basalt flows and related hyaloclastite that have Nb/Y = 0.60 and high TiO2 contents (average = 2.8 wt.%). This chemistry is consistent with rocks of the Brunswick Mines member (Little River Formation), except that these rocks are considerably enriched in P2O5 (average = 0.82 wt.%). This syngenetic exhalative deposit is unique for the BMC with a high Pb/Zn and elevated Au and Ag contents, as well as an epithermal signature (Sb-Ag-Au-Tl-Hg), analogous to high sulfidation volcanogenic massive sulfide deposits. Its intimate relationship with an emergent felsic dome (Flat Landing Brook Formation), chlorite-silicate-oxide-sulfide exhalite (locally hematitic), and the abundance of barite are classical features of many of the Kuroko deposits."

Jan 1, 2006

By G. S. Dobby, J. A. Finch

"I. INTRODUCTIONA significant development in flotation over the past few years has been the increasing industrial use of flotation columns, primarily in Canada. The column differs dramatically from conventional mechanical flotation machines, both in design end operating philosophy, which has been a principal reason for its slow acceptance by the mineral industry. Boutin, Tremblay and Wheeler (1. 2) developed the concept in the early 1960's and since then plant and laboratory columns have been marketed commercially by Column Flotation Company of Canada Ltd. In 1980-81 at Mines Gaspe, Quebec, three columns replaced 13 conventional cleaners in a molybdenum upgrading circuit, with superior results (3). Since then many of the copper producers in British Columbia have installed columns for copper and molybdenum cleaning, including Gibraltar, Lornex, Highmont and Island Copper. There now appears to be widespread interest in flotation columns.The column is particularly attractive for applications involving multiple cleaning stages and can upgrade In a single stage compared with several stages of mechanical cells. This results in simpler, more controllable circuits. Importantly, the column itself is well suited to computer control. A significant problem, however, has been that of translating laboratory data to plant performance. The purposes of this communication are to address the problem of column scale-up and to describe some of the transport mechanisms of a flotation column, leading to a kinetics based model.A schematic of a flotation column is shown in Figure]. Industrial columns are up to 13 m high and 0.3 to 1.8 m in cross section (either square or circular). Three zones can be identified:a collection zone, with feed entering 2 to 3 m below the top of the column and descending against rising bubbles generated at a gas sparger; a washing zone, where a packed bubble bed is generated by a downward flow of wash water; and a conventional froth (2 - 5 cm thick), the sole purpose of which is particle transport to the launder. The tailings withdrawal at the bottom of the column is controlled at a rate slightly greater than the feed flowrate (called a positive bias).An important element is the washwater, added just below the froth zone. The component of the washwater that flows downward (to make up the bias) is sufficient to prevent coalescence of rising gas bubbles. The packed bubble beg so generated is very efficient at suppressing gangue entrainment to the concentrate."

Jan 1, 1985

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 Neil McMillan

"By any measure of common practice, Claude Resources' Seabee Gold Mine in Northern Saskatchewan should not now be operating. Not because reserves dwindled, or grade dropped or prices weakened or technical problems arose, but because a host of unimaginable other problems beset the project, any one of which would normally have led to the mine's failure.The success of the Seabee Mine, and it is extremely successful, is a story of the vision and blunt determination of two men. Neither is remarkable in his own right but each possesses the characteristics which were necessary to forge a highly productive and profitable narrow-vein mine in the midst of the most bizarre and unpredictable events which likely have ever beset a mine start-up in Canadian history.Together, Bill MacNeill, a Saskatchewan born, former bush pilot and Ray Gagnon, a big hearted, hard-fisted, miner with 44 years of experience in Canada's underground, built the Seabee Mine.They didn't accomplish this with brilliant geology, outstanding engineering or nimble corporate manouvering but rather a stubbornness and raw common sense which likely are all too often, ingredients missing in failed projects.The Seabee Mine is 100% owned by Claude Resources, a Saskatoon based company taken over by Bill MacNeill, its current chairman, in 1982. The company is listed on the TSE and produces 1200 barrels of oil per day and about 60,000 oz of gold per year. The company has a strong balance sheet, is very profitable and has 18 million shares outstanding.The Seabee property in Northern Saskatchewan started out like many other gold exploration properties in Canada.It was discovered in the l 940's by what is now Cominco, and, while highly regarded by that company the property sat largely dormant until acquired by Claude Resources in 1985.Claude did what most junior exploration companies would do and went looking for a company with a depth of expertise to joint venture the property.That company was Placer Development who could earn a 55% interest in the Seabee by delivering a bankable feasibility study on the Project by July 1988 and providing financing to production.Placer Development was an excellent company and spent over $8 million dollars on the Seabee over a 3 year period. Unfortunately for Claude Resources, Placer Development merged with Dorne Mines in 1987 and the new merged company, Placer Dome, established a minimum production threshold greater than the 50,000 oz per year which the Seabee appeared capable of supporting at that time. Placer Dome's request for an indefinite extension of the joint venture agreement to allow it to drill off a larger ore body was rejected by Claude Resources and the Seabee Property was returned to Claude in 1988."

Jan 1, 1998

By L. K. Walker, G. A. Kosick, P. D. Young

"MillEX is an information management system designed by mineral processors for mineral processors. The system utilizes ""cutting edge"" software technology to gather and store all automatically and manually recorded data from the plant operation and laboratories. This data is delivered to the desk of superintendents, metallurgists, technicians and managers, and permits the user to query, correlate, graph, report and present this data in minutes. In the past this task would have taken days and even weeks of tedious work to complete.MillEX allows the engineer/analyst to quickly develop a very thorough understanding of the complex relationships of process variables and equipment that exist in the plant, and their effect on product quality and quantity. The time and resources that are currently wasted on duplicating data entry will be an effort of the past.This paper describes the structure of MillEX and how it conforms to the needs of mineral processing personnel.INTRODUCTIONPicture a personal computer on your desk which will carry out the following commands:1. Plot a graph over the last six months, using weekly averages, of percent minus 200 mesh material in the primary cyclone overflow.2. Overlay this graph with a graph of concentrate grade versus recovery over the same time period.3. Retrieve a prior month end report, update all operating supplies tables and metallurgical performance with this months data, and embed the graphs created above.4. Edit text and print the current month end report. This is only one example of the type of power MillEX isbringing to the mineral processing industry."

Jan 1, 1992

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 E. A. Lowe, J. W. Smith, C. W. Overton

"The operations of Bethlehem Copper are situated in the south-central interior of British Columbia at an elevation of 4900 feet above sea level. Main road and rail transportation systems pass through Ashcroft in the Thompson Valley, which is 28 miles by road from the minesite. The operation was the first low-grade open-pit porphyry copper mine in British Columbia.The minerals are chiefly chalcopytite and bornite, while the rock is principally feldspar and quartz. In the outer fringes of the orebodies some pyrite is present. Average grade of mill feed is 0.55% copper.History of Milling Operations Production commenced in December 1962 at a rate of 3,000 tpd in a plant that comprised two-stage crushing followed by rod and ball milling. Production ratings were increased to 6,000, 10,000 and 12,000 tpd by the addition of a further stage of crushing and more rod and ball mills. When the last expansion was completed tonnage throughput exceeded the 12,000 ton designed rate and was stabilized at 15,500 tpd.However, recovery did not meet expectations at the expanded rate because of coarse flotation feed. Capacity in the rod mill circuits exceeded the subsequent fine grinding capacity, resulting in poor liberation. Studies were initiated to improve recovery without decreasing throughput.Description of Operation Prior to Pebble Milling Crushing with primary, secondary and a closed tertiary stage proceeds at a scheduled 20.5 shifts per week. Fine ore screened on 1/2"" x 4"" apertures is stored in a 30,000-ton bin ahead of two 12.5' x 15' rod mills. Rod mill discharge joins secondary ball mill (one 10.5' x 14' and one 11' x 14') discharge for classification in a single 50"" cyclone which closes the secondary mills. Overflow from this cyclone is split between three third-stage ball mill-pump-cyclone circuits (two 11' x 14' and one 12.5' x 15'). Prior to addition of the two pebble mills the flotation feed was produced by this three-stage grinding system. Grinding criteria are shown in Table I."

Jan 1, 1975