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By S. Onuki, T. Ando, M. Tejima, R. Enomoto, Y. Okada

"Al–Si–Cu–Mg die casting alloys are widely used in the automotive industry, and recent advancements in high pressure die casting technology enable heat treating products to achieve desirable properties. However, CO2emissions associated with die-casting production lines should be reduced to address the global warming issue. In this study, the relation between the microstructures and thermal stability of precipitates formed during isothermal aging at 423, 485, and 558 K of Al-11.0 mass%Si-1.8 mass%Cu-0.2 mass% Mg (JIS ADC12) was investigated using Vickers hardness tests and transmission electron microscopy (TEM). The hardness tests and TEM results showed that Si compounds and Al–Cu compounds enhanced the mechanical properties of the alloy and that the predominant compound affecting the mechanical properties differed between specimens treated at 423 K and those treated at 558 K. Moreover, additional aging at 423–458 K resulted in a material with a Vickers hardness higher than that of the isothermally single-aged material. Differential scanning calorimetry, differential elemental analysis, and selected-area diffraction analysis using TEM suggested that the combination of Al–Cu compounds precipitated at low aging temperatures and Si compounds precipitated during preliminary aging increased the mechanical strength, resulting in a maximum hardness of 130 HV.INTRODUCTIONAl–Si–Cu–Mg die casting alloys have well-balanced mechanical properties, machinability, and cast ability. These alloys are therefore widely used in the automotive industry because of their superior characteristics, accounting for>90% of the aluminum used in die casting production. As a substitute for iron-based materials, these alloys have contributed to the development of lightweight vehicles.Dong et al. (2014) reported that the heat treatment of die casting materials is effective for changing their dimensions under high temperatures as a result of the precipitation of solid-solution elements. Recent advancements in high pressure die casting technology have led to the application of heat treatments of Al–Si–Cu–Mg alloy products to reduce fuel consumption and satisfy customer needs. Although attempts to reduce CO2emissions have focused on fuel consumption in cars and fuel efficiency regulations have become increasingly strict in recent years, CO2discharged from production lines should also be reduced without adversely affecting the properties of the product. Heat treatments for artificial aging after solution treatment (T6 treatment) and after casting (T5 treatment) are CO2discharge sources, which together with a holding furnace account for >80 % of the CO2discharged during the casting process."

Jan 1, 2018

By G. Styles, K. Lye, R. Tenbergen, M. Mayhew

Requirements to produce a higher bulk concentrate grade have necessitated extensive use of on-stream analyser data and computer programming to obtain the targets set for Frood Stobie Mill as required by overall milling considerations.A brief history of milling process changes associated with the changes from a low grade (3% Ni) bulk concentrate in the sixties to a high (6 to 8.5%). Nil bulk concentrate currently will be presented.The heart of the presentation will be the computer control schemes for ""self optimisation"" of the distinct flotation sections in the plant within certain restraints to achieve targets set by the mill metallurgist.

Jan 1, 1985

By B. Samanta

Abstract - Ore reserve estimation, based on sparse drill hole data, was conducted for a placer gold property in Nome, Alaska. A problem with sparse data is that random subdivision of the data into modelling and evaluation subsets (as is commonly done) becomes a problem, as random selection may result in biased/skewed subsets. Therefore, a technique that combined data segmentation with genetic algorithms (GA) was applied to divide the samples into three equivalent subsets: training, validation and testing. Data segmentation was done on the basis of the distribution of gold values. Neural network and a variety of kriging techniques were used to estimate gold grades. A multi-layer feed forward neural network along with "early/quick stop" training was used for neural network modelling. A comparative evaluation of kriging and neural network methods was then performed. The results revealed that neural network was generally superior to the kriging techniques for gold grade estimation in the Nome deposit.

Jan 1, 2002

By Peter Fullagar, Adel Vatandoost, Steve Walters, Toni Kojovic

"Traditional comminution tests are a vital component in every mine plant design. Comminution behavior governs both the cost of equipment and its operating efficiency. Most comminution tests are conducted off site on a limited number of samples, owing to the high costs and long lead times involved. Therefore a strong incentive exists to find alternative means for efficiently characterizing comminution behavior for a truly representative suite of samples. The potential for inferring comminution behavior from drill core is investigated in this paper. Our approach involves development of small scale comminution tests on the one hand, and measurement of a wide range of core attributes on the other. Our focus is the relationship between petrophysical properties and comminution behavior.Petrophysical properties of archival diamond drill core from the Ernest Henry Mine (Queensland, Australia) have been measured using a Geotek multi-sensor petrophysical core logger. We have investigated the relationship between the petrophysical properties and the corresponding small scale A*b and estimated Bond mill work index test results for 2m composites of the core. Core samples were petrophysically classified by means of cluster analysis. Comminution behaviour was then modeled for each cluster via multiple regression. The results suggest that prediction of the comminution behavior on the basis of petrophysics is viable at Ernest Henry.INTRODUCTIONMineral processing is the most important downstream operation for mining engineers and metallurgists since most mined materials are subjected to some type of comminution or beneficiation operation (SME, 1992). Comminution or size reduction is typically the first stage of processing. Size reduction steps (crushing and grinding) in any plant consume large amounts of energy, normally more than 50% of total energy (Weiss, 1985). Therefore, it is desirable to obtain laboratory results to design the size reduction equipment appropriately. One of the main factors that control the selection of hard-rock crushing equipment and the design of a crushing circuit is the mechanical character of the ore(s). Work index, density, abrasivity, compressive strength and clay content are essential parameters for ore characterisation (SME, 1992)."

Jan 1, 2009

By Chen Xia, G. Deschenes, Wan-Tai Yen

"Ammonium thiosulphate is a potential replacement for the cyanide in gold leaching. However, the high reagent consumption hinders its practical applications. In order to reduce the thiosulphate consumption, chemical additives were used. The gold leaching tests were conducted on a sulphide copper-bearing gold ore with 0.3M thiosulphate, 0.03M copper sulphate and 3M ammonium hydroxide solution at 44% solids and pH 10.2. Sulphate, sulphite, amino acid and chelating agents were initially used as additives. It was found that chelating agents (EDTA and NTA) could reduce the thiosulphate consumption from 30 kg/t to 17.8 kg/t with some increase of gold extraction. The improvement from other additives was not significant. Other approaches were also attempted to reduce thiosulphate consumption with some success. The thiosulphate consumption could be reduced to about 17 kg/t by reducing copper sulphate concentration fiom 0.03M to 0.0015M; adding 0.04M of EDTA; replacing copper sulphate with 0.001M of nickel sulphate. The increase of pulp density fkom 44% to 60% solids could reduce the thiosulphate consumption to 17 kg/t as well. Limiting the dissolved oxygen content by sparging nitrogen reduced the thiosulphate consumption further to 10 kg/t. It could be concluded that the regulations of copper and oxygen supply in the lixiviant were the keys to reduce the reagent consumption.INTRODUCTIONCyanidation, as the predominant gold leaching method, has been used in mining industry for more than a century. The low reagent requirement and the high performance are the reasons for its great success. However, cyanidation cannot deal with ores containing large amount of copper, nickel, arsenic and zinc minerals. This type of ore may consume more reagents and result in a poor gold extraction. On the other hand, the carbonaceous materials may preg-rob the gold from pregnant solution and make cyanidation a problem leaching method. Further more, the high toxicity of cyanide represents another challenge to modern gold mines. In the beginning of the year 2000, an environmental disaster caused by an accidental spill in Yugoslavia was broadcasted world-widely (Gurevitch 2000). Gold mine operators are facing higher social pressures and increasing costs on environmental protections. The usage of cyanide in mining industry has been banned in some countries and locations such as Czech Republic, Japan, Turkey, California, Colorado, Wisconsin and Montana States. Thus, a non-cyanide lixiviant is required."

Jan 1, 2002

By H. A. Khorami, T. Wong, B. Velapatino, E. Asselin, T. Donnelly, E. Bryce, R. Dixon

A copper–nickel concentration gradient alloy was designed and fabricated through a powder metallurgy (PM) process. Copper and nickel powders were mixed with different weight ratios from 0 to 100% copper in 10% increments. Each powder mixture was poured inside a cylindrical die and compacted between two punches using a hydraulic press machine at pressures up to 70 MPa, resulting in approximately 1 mm thick layers (discs) of pressed Cu–Ni powder. These 11 Cu–Ni compacted powder layers, i.e. 0–100% Cu with 10% increments, were then compressed together with pressures up to 420 MPa to form a green part. The green part was sintered in a vacuum furnace at 1000°C for 10 hours to form a solid mass (PM part) of Cu–Ni concentration gradient alloy. In the sintering process, Cu and Ni particles fused together and formed a single piece due to diffusion of the atoms across the boundaries of the particles. The diffusion of atoms also converted the stepwise concentration change into a uniform concentration gradient. INTRODUCTION Copper has numerous applications in different industrial sectors due to its superior physical, electrical, mechanical and chemical properties such as its excellent thermal and electrical conductivity, resistance to fatigue, high ductility, and resistance to corrosion. Moreover, copper and its alloys have natural antimicrobial properties. This has opened up new applications for copper–based self–disinfecting surfaces in healthcare in an effort to mitigate healthcare–associated infections (HAIs). HAIs affect millions of patients each year, leading to significant morbidity and mortality as well as financial losses to healthcare systems (World Health Organization, 2016). HAIs spread through three main routes: (a) iatrogenic in which HAIs are a direct consequence of medical encounters and/or treatment; (b) person to person where organisms are transferred between healthcare workers, patients, and visitors; and (c) environmental where transmission occurs via contaminated surfaces and equipment (e.g. doorknobs, railings, toilets/commodes, medical carts). The use of antimicrobial copper–based materials on high touch surfaces could diminish pathogen transmission via this latter rout. This has subsequently led to the development of a variety of copper–based materials for use in healthcare settings and promoted the investigation of the antimicrobial efficacy of copper–based materials.

Jan 1, 2019

"The Cooperative Research Centre for Mining Technology and Equipment (CMTE) is funded by the Commonwealth Government, by its mining research members — the Universities of Queensland and Sydney and the CSIRO1, and by its industry members — BHP Coal, RioTinto R&TD, Hamersley Iron, Mining Technologies Australia, Pasminco, Shell Coal, WMC Resources, Advanced Mining Technologies, and Aberfoyle. The Centre conducts work aimed at improving the competitiveness of the Australian mining industry. The current work is focused in four areas: new mining and drilling systems, geological sensing, automation, and equipment maintenance and reliability. This paper describes much of the work in these program areas that relates to metalliferous mining. Mechanized Rock ExcavationThe disadvantages of the drill-and-blast excavation method are widely recognized and the last half of the 20th century has seen mining companies and mining research organizations aggressively pursue technology to excavate rock by other means. As discussed below, despite considerable effort and large amounts of funding, the quest for mining’s “Holy Grail” has been unsuccessful in all but the weakest rock types.COMRO (the Chamber of Mines Research Organisation) supported by the South African gold mining industry, spent three decades and (probably) tens of millions of dollars developing prototype drag bits and, later, impact breaking machines aimed at the mechanized stoping of narrow, tabular reefs. This work has not yet produced a commercially-attractive mining system. Work continues in South Africa to mechanize these stoping operations although now the emphasis is on the use of diamond-wire sawing techniques. This work remains in the experimental phase.Both British Coal and Germany’s Bergbau- Forschung spent many years developing techniques trying to extend the range of rock types which roadheaders could cut economically. Again, although new knowledge was produced, it is difficult to claim that any new commercial mining systems emerged from this work."

Jan 1, 2001

By W. A. Ahrens, J. H. McNamara, J. G. Franek

"An economical, pollution-free process has been developed for the hydrometallurgical extraction of copper from sulphide ores. The extracted copper, in the form of cuprous chloride (CuC/), is converted by reduction to copper metal. The metal is melted and fire -refined into wire bars which meet the standards of electrolytic tough pitch (ETP) copper wirebars. IntroductionThe successful development of the Cyprus Copper Process has been an evolutionary series of events covering a time span of some nine years. The original process, based on an electrolytic membrane cell principle , was abandoned in 1975 because of technical, economic and pollution problems. During the past four years, the pilot plant has been reconstructed based on a new flowsheet and operated successfully in several campaigns, some for as long as four months. The pilot-plant hydro section operates at a 225-lblhr copper rate. In October 1977, a feasibility study was completed by Jacobs Engineering, Pasadena, California. The study showed favourable economic and technical feasibility. Jacob's studies in 1978-79 revealed favourable comparative economics with other known pyrohydro processes and favourable economies of scale.The Cyprus Copper Process converts copper concentrates of varying composition into copper metal, which has been proven to be equivalent in every way to electrolytic tough pitch copper, suitable for electrical applications. This is accomplished at capital and operating costs which are estimated to be lower than those associated with any other known currently applicable technology. Also, the total energy requirement is equal to or less than any other known process and the process is essentially pollution free."

Jan 1, 1980

By M. Mirnezami, J. A. Finch, S. Uddin

A fast, reliable and practical way of measuring zeta potential using sedimentation potential method is proposed. A cell was designed along with the instrument control software to determine the required variables simultaneously i.e. sedimentation potential, specific conductivity, volume fraction of solid as well as pH. High purity alumina and silica powders were used as test samples. Measured zeta potential using the proposed technique was comparable with the results by electrophoresis.

Jan 1, 2009

By J. Frostiak

"This paper describes some energy reduction measures Implemented at the Griffith Mine. Before proceeding, I will give you a brief overview of the operation.The Griffith Mine is an iron ore mining, concentrating and Pelletizing complex located in the red lake area of northwestern Ontario. The operation is owned by Stelco Inc. And is managed By Pickands Mather & Co. of Cleveland, Ohio. Operation of the concentrator commenced in 1968 and it has been producing at a nominal capacity of 1,500 ,000 tons annually.The plant flow sheet is illustrated in this slide. Run of the mine ore is crushed in a single stage 54"" gyratory crusher. Reclaim ore feeders draw from an open stockpile to feed two 32' diameter by 12' long autogenous mills, each driven by 6800 hp. Two s·rages of wet magnetic separation, roughers and cleaners, and primary cyclones complete the primary circuit. Cleaner concentrate is then ground in four 14' diameter by 28' long pebble mills rated at 2000 hp. The secondary grinding circuit is closed by cyclones and fine screens. Secondary cyclone overflow is further upgraded through hydro-separators, finisher magnetic separators and flotation.The magnetic concentrate produced is then thickened, filtered, balled and fired in three vertical shaft furnaces to produce a high quality hematite pellet."

Jan 1, 1983

By A F. Kravic

Carbonyl nickel powders of irregular particle shape and low a11parent density are used extensively in the production of porous nickel electrodes for nickel-cadmium storage batteries and hydrogen-oxygen fuel cells employing alkaline electrolytes. Such porous nickel matrices are at-tractive for these intended applications as they are relatively inexpensive, are corrosion resistant, have good electrical conductivity, can be welded to form electrical contacts, have a long life (as demonstrated in alkaline storage batteries), and are rugged and vibration and shock resistant. This paper describes a feasibility study concerning the production of porous multi-layer nickel electrodes by the pressing and sintering of stacked layers of green-powder rolled nickel sheet. Background H AUSNER (1) conveniently listed nine different powder compaction processes used for forming metal powders into useful shapes. These are shown in Table I. There are additional powder metallurgy processes; however, most of these are combinations of two or more processes listed in the Table. A study of the literature revealed that every powder compacting process, with the exception of isostatic pressing and explosive forming, has been evaluated or is being used for the manufacture of porous metal electrodes.

Jan 1, 1965

By A. J. Williams

"Conventional base metal milling practice normally consists of crushing, grinding and cyclone classification followed by flotation. It is the authors' belief that the commencement of flotation after cyclone classification leads to inferior metallurgical results and that implementation of flotation of grinding mill discharges can result in increased recovery due to reduced overgrinding, reduced activation of contaminating minerals and improved dewatering circuit results due to the production of coarser concentrates.The concept of recovering minerals from the discharge of grinding mills is not new! Gold concentrators have utilized jigs and flotation cells while iron ore plants have employed magnetic separators to recover gold and magnetite respectively from the discharge of grinding mills. More recently, a Reichert cone has been used to recover sulphide and oxide base metal minerals from screened rod mill discharge. 1To the authors' knowledge, the first application of flotation of base metal minerals from the discharge of a production plant grinding mill was at the Lake Dufault concentrator of Corpor'1tion Falcon bridge Copper. Located 10 miles north of Noranda, Quebec the Lake Dufault concentrator commenced operations in August, 1964.The installation of flot11tion cells in the Lake Dufault grinding circuit proved so successful that an identical system was installed in the Manibridge concentrator of Falconbridge Nickel Mines Limited. Located 90 miles southwest of Thompson, Manitoba the Mamibridge concentrator commenced operations in June, 1971 and due to exhaustion of economic ore reserves discontinued production in May 1977."

Jan 1, 1984

By John Starkey

"During the period June 2007 to March 2007, John Starkey of Starkey & Associates (Starkey) worked in Russia for High River Gold, supervising the engineering design work that was being done at the IRGIREDMET Research Institute, in Irkutsk Russia. The work entailed moving the Newmont No. 4 mill from Elko, Nevada to Berezitovy, a mine site north and west of the city of Skovorodino, in the Amur Region of Siberia. This was a grass roots project and required construction of all phases of the infrastructure and process facilities that are associated with a 5000 t/d open pit mine and CIP mill.During the course of this engineering design exercise, many aspects of doing business in Russia were encountered, with regard to laws, norms, and business practices. This paper discusses many of these findings. Also by living in Irkutsk, many observations on Russian life and social customs were made and these merit discussion from a general interest point of view.Prior to going to Russia, another engineering and ore testing firm (TOMS) had approached Starkey to find out if Starkey could assist them in upgrading their SAG ore testing procedures to Western standards in order to offer their clients turnkey projects, that included reliable SAG and AG grinding. TOMS was aware that Starkey had invented the SPI test but did not know that the SAGDesign test had by then been fully developed and was being offered commercially as the most accurate way in the world to design new grinding mills. They were also unaware that this new testing method had been patented by Outokumpu (now Outotec) and that this method allowed them access to a design method, through Starkey, that would lead to a manufacturer’s guarantee (by Outotec) of throughput and grind for any new semi-autogenous or autogenous grinding circuit, with or without ball mills.When Starkey started working at IRGIREDMET in June 2005, they also made a request to add a design method for SAG mills that would be considered acceptable to Western clients. From these requests, presentations were made in Russian to both institutes and each decided to join the SAGDesign Consulting Group as satellite members and buy a SAGDesign test mill to use with their Bond Ball Mill Work Index mills, to provide SAGDesign testing services. To complete the service, contracts have been put in place for Starkey to use these results to design new grinding equipment and to train engineers at TOMS and IRGIREDMET how to do this work.Starkey also undertook to train engineers at both labs to go into the field and to take the samples for SAGDesign testing programs. It is here where the SAGDesign testing service upgrades other grinding test programs because the samples to be used for design are professionally chosen, and the results will be much more likely to produce a satisfactory design. Starkey is a mining engineer and is uniquely qualified to do this task. This and the SAGDesign test are the key components that lead Outotec to offer a performance guarantee for mills designed by Starkey."

Jan 1, 2008

By J. Guha, A. Gobeil, P. Pilote, A. Tremblay, E. Dimroth

The Mount Bourbeau Lac Berrigan area is located just to the north of the Town of Chibougamau. The axial trace of the Chibougamau syncline borders the northern part of both areas. The area contains Archean rocks of the Roy Group, intruded by the Cummings Complex and the Line Lake tonalite stock. Proterozoic sedimentary rocks occur in a series of outliers. Various Cu, Zn, Pb, Ag, Au and Mo showings are dispersed over the area in a wide range of time and space. Pre-Kenoran (stratiform and stringer) showings related to volcanic activity may be distinguished as well as the syn-or post-Kenoran (vein) types whose nature is imprecisely known. In this area, the stratiform showings occur in the Gilman and Blondeau Formations, whereas the vein type showings occur for the most part in fractures or breccias within or along the contacts of the various sills of the Cummings Complex. Mount Bourbeau is distinguished by the greatest variety of showings as well as the proximal volcanic facies of the Blondeau Formation. A volcanic centre is presumed to lie a short distance north or east of the locality. Locally, the Line Lake stock contains significant silver, molybdenum and gold mineralization. Its role as a metal reservoir, a source of heat for the circulation of hydrothermal fluids and its control of the local tectonic style remains to be determined.

Jan 1, 1984

By C. A. Grandison

The economic evolution from an agrarian society to an industrial and service-oriented economy is apparent to most students of history. The long-term trend is almost taken for granted, it does not require explanation — it is accepted as the nature of man to improve his standard of living. However, there are fluctuations around this trend line which have provoked a great deal of thought. The ability to understand and control these fluctuations would yield many benefits, it would eliminate economic waste and public hardship, and would no doubt make a few fortunes. I f it is not possible to control or eliminate these fluctuations, then a reasonable forecast of the tinting, rate of change and magnitude of the fluctuations would be invaluable to industry and government.

Jan 1, 1976

By Ralph Harris, Qi Xia

"Gold cyanidation rates are known to be limited by the rate of oxygen dissolution in the cyanidation tanks. The effect of solids loading on the oxygen dissolution rates is not obvious and the results of previous studies are ambiguous. The present paper presents an analysis of oxygen dissolution rates using a ""spent"" commercial gold slurry diluted to various levels of solids loading. It was found, in an 170 litre stirred tank reactor using an inverted cone sparger, that under certain high loading conditions, there was a decrease of as much as 50 %, i.e., there was a halving of the rate of oxygen dissolution as compared to that in clean water. In particular, it was observed that, due to gas flooding of the impeller, there was a drop in kLa even with an increase of gas velocity. Gas holdup reached a maximum value of only 1.7 %. The total power consumption was between 0.06- 0 .10 kw/m3 within the range of gas velocity before flooding occurred. The decrease in oxygen dissolution rate with increased solids loadings is believed to be mainly due to the increase in the apparent viscosity which reduced the turbulence and shearing effect and resulted in larger bubbles and hence reduced the reaction area a. The interrelations between solids loading, gas holdup, flow pattern, power consumption, and liquid mass transfer coefficient are discussed.IntroductionThe reactors generally used in gold cyanidation are Stirred Tank Reactors (STR). Compared with other types of reactors like fluidized bed reactor and column reactor, STR is of particular importance due to its wide application in industry. It is reported that the stirred tank reactor is used for more than 50 % of the world's chemical production (Xu and McGrath, 1996)."

Jan 1, 1997

By Marc Legault

The Duparquet mining camp situated along the Quebec segment of the Porcupine-Destor Fault was the site of gold exploitation from 1933 to 1956 and 1988 to 1991. Numerous gold showings and deposits straddle the fault. An ongoing regional metallogenic study by the Quebec Geological Survey has identified five main types of gold mineralization, each showing a distinct style, alteration, control, metal content, and timing. In order to maximise the impact of this study, a 3D regional common-earth-model was constructed along a critical segment of the Porcupine-Destor Fault with the gOcad® technology. The realisation of this model required the maximum use of the public SIGEOM numerical database, as well as the recovery of significant private data from exploration company partners. The 3D model is also a powerful new dynamic exploration tool, which can be queried using geological criteria characteristic of the different gold deposit types. This 3D model can be modified and improved continuously by adding data from new drilling, mapping or geophysical surveys. The case of the Porcupine-Destor Fault illustrates the importance of 3D common-earth-modelling in delivering refined technological geological syntheses likely to attract significant investments from the mining exploration industry, especially for deep exploration programs within mature mining camps.

May 1, 2004

By Mike Ounpuu

"Locked cycle testing has become more common practice in the last 10 years. Reasons vary from a desire to avoid pilot plant testing, demand for more variability testing within deposits, and perhaps most importantly, a request from the financial institutions who invariably finance many of the projects. Surprisingly, many people don’t understand locked cycle testing, analysis and balancing. This paper provides a brief overview of locked cycle testing, and then progresses into a more detailed discussion on the analysis and balancing of locked cycle test data. The paper endeavors to educate CMP personnel on how to determine if the test was good and if a reasonable metallurgical projection was made. The paper uses case studies to illustrate the key points.INTRODUCTIONA locked cycle test is a repetitive batch used to simulate a continuous circuit. The basic procedure has a complete batch test performed in the first cycle which is then followed by similar batch tests which have “intermediate” material from the previous cycle added to the appropriate location in the current cycle. These batch tests, or cycles, are continued in this iterative manner for an arbitrary number of cycles. The final products from each cycle, i.e. final concentrate and final tailings, are filtered and thus removed from further processing. At the end of the test, all the products, final and intermediate, are dried, weighed and subjected to chemical analysis. The test is balanced and a metallurgical projection is made.This description can be found in many of our classical textbooks for the mineral engineer 1, 2, 3,4. Unfortunately, none of these textbooks provide any discussion beyond the basic procedure. Often, they provide comments such as in Taggart’ where he states; “It is questionable whether in any case it approximates mill results any more closely than the standard batch test”. It is truly surprising that our classic textbooks promote that locked cycle tests are more art than science, and suggest that they can be of dubious value. None of the textbooks provide meaningful insight or discussion in how to assess:"

Jan 1, 2001

By Claude Bazin, François Robichaud

"The control of the operation of semi autogeneous grinding (SAG) mills is mainly achieved through adjustments of feed rate, water addition and speed of rotation. With the introduction of image based sensors it is possible to have on-line measurements of the size distribution of the ore feeding a SAG mill. This information could be used for the development of a control strategy to regulate a SAG mill feed size distribution to a set-point. The control of the size distribution is carried out by adjustment of the speed of the ore extractors underneath the ore stockpile. The potential and difficulty associated with the implementation of such control are assessed using a multivariable statistical analysis of data collected from the operation of the grinding circuit of the Agnico-Eagle Goldex mine in Val d’Or, QC. A control strategy for the ore feed size distribution is assessed using a simulator of the ore stockpile operation.INTRODUCTIONThe popularity of autogeneous (FAG) and semi autogeneous (SAG) grinding mills has been increasing over the last 20 years (Napier Munn et al., 1996). These mills use the ore or a combination of ore and steel balls as the grinding media. Since the ore is used as a media for the size reduction the mill ore feed size distribution impacts the performance of the mill. Several papers were recently published on this subject (Dance et al.,2011; Wennen & Murr, 2011; Dance & Valery, 2011; Allaire et al., 2011) showing the advantages of preparing the feed size distribution to maximize the circuit throughput or mill efficiency (Wennen & Murr, 2011; Dance & Valery, 2011; Allaire et al., 2011). With the availability of particle size sensor based on image analysis of the ore on a conveyor (Partanen et al., 2001; Bobo et al. 2004; Edwards et al., 2002; Wei & Craig, 2009) it is possible to control the size distribution of the ore feeding autogeneous or semi autogeneous mills (Partanen et al., 2001).This paper describes a method to control a size distribution index to a set point via the manipulation of the speed of the extractors that withdraw the ore from the stockpile feeding the grinding circuit. The paper consists of 4 sections. The first section describes the considered grinding circuit. A statistical analysis of the collected data on the grinding circuit is presented in the second section. This analysis demonstrates the necessity of using real-time adaptation mechanisms to develop a control strategy for the size distribution of a grinding circuit. The third section describes the method used to simulate the ore stockpile operation and the last section describes the preliminary development and assessment of a control strategy of size distribution of the ore feeding a SAG mill."

Jan 1, 2013

Mine Evaluation Engineering , Operational and Social evaluation. Focus is on what opportunities are available. Social ??History ??Past Management Practices ??Community / Available labor force Mining Method / Equipment ??Competent rock ?little support required, no backfill ??Shallow mining ?ramp mining, no shafts or hoisting ??Large scale mining potential ??Simple rock breaking and crushing on surfaceMill Process ??Straightforward gold liberation process Create a Plan / Create a Team Following the feasibility 44-101. Key people were hired and a full operational Business Plan was developed. Focus is on how to get the job done. ??Scoping Study / Pre-Feasibility / Feasibility ??Operational Business Plan ??Hire key people ??Purchase key equipment

May 1, 2006