Search Documents

By Arthur L. de Carle

"IntroductionThe Key Lake uranium-nickel deposits are located within a Mineral Lease centred at latitude 57 ° 12' north and longitude 105 °39' west along the southeastern rim of the Athabasca sedimentary basin in northern Saskatchewan, approximately 240 km north of La Ronge (Fig. 1). Access is provided by an allweather provincial highway from Pinchousc, situated about 200 km to the south, and a private airstrip maintained at the mincsitc.These deposits have been developed by Key Lake Mining Corporation on behalf of the Saskatchewan Uranium Joint Venture. Participants in the joint venture include Saskatchewan Mining Development Corporation (50%), Urancrz Exploration and Mining Limited (33 1/3 %) and Eldor Resources Limited (16 2/3 %).Considerable geological work has been conducted on the Key Lake orebodies and reported in summary papers published by Dahlkamp and Thn, (1977), Dahlkamp, (1978), Gatzweiler eta/., (1979) and Kirchner el a/. , (1980). However, intensive geological research is ongoing, particularly since many problems regarding ore genesis and controls remain unresolved . Exploration History and DevelopmentThe events (Gatzweiler eta/., 1980) which led to the discovery of the Key Lake ore bodies began in the summer of 1971 by following up on the reports of airborne radiometric anomalies and anomalous radon values in the Zimmer Lake water situated approximately 5 km to 6 km to the southwest. This work succeeded in locating a few high-grade uranium and nickel-bearing boulders associated with esker material. An integrated program, consisting of various geochemical and geophysical surveys along with diamond drilling, culminated in the discovery of the Gaertner orebody during July 1975. Subsequent fence drilling across the strike extensions of this ore structure located the Deilmann deposit, approximately I km to the northeast, in June 1976"

Jan 1, 1986

By Corby G. Anderson, Caelen D. Anderson, Patrick R. Taylor

"The United States contains a variety of domestic rare earth element mineral sources containing such as ancylite, bastnasite, monazite, and xenotime. Research has been performed to investigate the fundamental surface chemistry involved in the froth flotation of these minerals, and apply the knowledge gained to substantiate the results through experimental testwork on a domestically sourced rare earth ore. This paper will outline the fundamentals and literature of rare earth mineral flotation, review its industrial applications and provide some recent research updates.THE RARE EARTH ELEMENTSRare earth elements (REE’s) are a unique family of elements with nearly identical physical and chemical properties. They account for approximately 1/6th of all naturally occurring elements, but the entire group occupies only one position on the periodic table. These 15 elements make up the lanthanide series (atomic numbers 57–71), and all but one (promethium) occur naturally. In addition to these 15 elements, yttrium and scandium are also considered rare earths since they tend to occur in the same deposits as the rare earths and share similar physical and chemical properties as seen in Figure 1. In particular Figure 2 denotes, a cartoon of the subtle differences in each caused by the 4f atomic sub shell (Gschneidner Jr., 1964). These subtle differences result in very difficult challenges in the selective concentration and final separation of each rare earth. (Anderson, 2015, Kronholm, Anderson, Taylor, 2013)Rare earths are separated into two different subsections; the “lights” or LREE’s (lanthanum57 through europium63) and the “heavies” or HREE’s (gadolinium64 through lutetium71). Yttrium is generally considered a heavy rare earth since its ionic radius is close to that of the HREE’s, while scandium is not considered either a light or a heavy."

Jan 1, 2016

By M. H. Allan

"This paper presents the geographic and geological setting of Saskatchewan Power Corporation's Poplar River Mine in south-central Saskatchewan, about 8 miles from the U.S. border. Generally the mine, which is being expanded to four million tons per year, is in an extremely disturbed geological area with severe dewatering problems. The lignite coal, which is strip mined, is supplied directly to an electric power generating station by means of a 7-mile unit-train private railroad.A number of unique reclamation and socio-economic problems were encountered because of the proximity to the U.S. border and because of the lack of experience of the regulatory authorities in projects of this kind. These are described in some detail, as well as the performance of one of the largest draglines in Canada. IntroductionThe Saskatchewan Power Corporation is a publicly owned utility which has the franchise to supply electricity and natural gas to all customers within the boundaries of Saskatchewan.Saskatchewan is a province which can almost be divided in two: the populated southern portion, principally devoted to farming, and the northern portion which is mostly on the Precambrian Shield and consists of lakes, rocks and muskeg. This portion is largely uninhabited except for a number of small villages. However, in the last few years there has been considerable mineral exploration and development, notably for uranium. This has helped considerably in the diversification of the basic agricultural economy of the province.Saskatchewan consists of 251,700 square miles, 761 miles north to south and an average of 335 miles east to west. It has a population of approximately 960,000, giving a population density of four persons per square mile. The Saskatchewan Power Corporation supplies 357,249 electrical arid 221,378 natural gas customers."

Jan 1, 1982

By H. Staton, V. Suontaka, E. Sharifi

"Flotation circuits are typically controlled using on-line elemental assays obtained from the slurry lines. In base metal applications, X-ray fluorescence (XRF) analyzers are the most common instruments for elemental analysis of the slurries. Eagle Mine has been utilizing a Courier XRF Analyzer since 2014. Typically, in XRF analysis, the sampling rate is 10-25 minutes which is good enough for manual process control. In 2018, Eagle Mine upgraded the Courier XRF analyzer with the Rapid Measurement module that is based on reflectance spectroscopy. This option reduces the sampling rate to 10-15 seconds, while maintaining the superior accuracy of the XRF analyzer. This paper presents the results from implementation of Rapid Measurement at Eagle Mine.INTRODUCTION Eagle mine is an underground mine producing nickel and copper concentrates. Eagle Mine is owned by Lundin mining and located in the Upper Peninsula of Michigan, USA. The Humboldt Mill, previously an iron ore processing facility, was refurbished in 2014 and is used to process the ore and produce separate nickel and copper concentrates. Approximately 2,000 metric tonnes of ore is milled per day. Ore is processed using a conventional crushing followed by single stage ball mill and flotation. Nickel and copper concentrate are transported to facilities in North America via rail car. A bulk copper-nickel concentrate is produced by separating the copper and nickel minerals from gangue material by flotation. The copper-nickel bulk concentrate is reground, followed by one stage of cleaning to reject further gangue minerals. The bulk cleaner concentrate is then subjected to a final flotation stage where the copper and nickel minerals are separated from one another through the addition of lime. Final concentrate grades are 14% Ni and 2% Cu in the nickel concentrate and 31% Cu and 0.8% Ni in copper concentrate."

Jan 1, 2019

By A. Sutherland Brown, Stuart S. Holfand

"The Northeastern part of the Cariboo district lies in the big bend of the Fraser River between Quesnel and McBride. The area shown on Figure 1 extends from just west of Wells to Isaac Lake, about 30 miles across the regional strike of beds.Topographically the area extends from the moderately well dissected Interior Plateau in the west through a transition zone to the fully dissected Cariboo Mountains in the east.The area is an important source of lode and placer gold. The Cariboo Gold Quartz and Island Mountain lode-gold mines have produced more than 32 million dollars in bullion since 1932. Placer-mining has probably produced an equivalent or greater amount, although only 15 million dollars is officially recorded because accurate statistics. were not kept until fourteen years after the origiiaal gold rush of 1860.The regional structure of the Barkerville district was summarized by Lang in the Jubilee Volume (1948, pp. 141-149). Since then a large amount of detailed and areal mapping by the writers has expanded the information available and made necessary a complete revision of the regional geology. Much of the information summarized in this paper, together with a full discussion of the revisions, may be found in British Columbia Department of Mines Bulletins, Nos. 34 and 38, but other information is as yet un-published.Rocks of the Kaza group are exposed in the core of the Lanezi anti-clinorium between Spectacle and Isaac Lakes. The main part of the group is composed of greenish micaceous greywacke and greenish schist with knots of garnet, biotite, or both, and minor amounts of pebble conglomerate. The upper 1,000 feet is composed of white to brown quartzites and brown phyllites. Altogether, about 6,000 feet of the group is exposed. 1t is of latest Precambrian, i. e. Windermere, age."

Jan 1, 1949

By Brian Lewis

"IntroductionThe ion exchange process is classed as a purification and concentration stage. In the uranium industry it is used to separate, and recover uranium, from a solution produced in the leach and subsequent solid washing circuit, that contains uranium as well as some impurities. The final product from this circuit is a solution, containing uranium at a 15 to 25 fold increase in concentration, with a chemical composition suitable for the ""Precipitation"" circuit.The process is a reversible chemical ""ION"" exchange, between a solution, and solid phase, with the ""resin"" being the solid phase. Various chemical changes in the solution phase will permit the resin to remove uranium from a solution or have the uranium removed from the resin back into a solution phase. The former loads uranium onto the resin, and is called the ""adsorption cycle"", and the removal or stripping is known as the ""elution cycle"".Ion Exchange resin is a semi-rigid polystyrene spherical bead, approximately 10 to 30 mesh. It is used by placing the resin in a vessel, so that a porous bed of resin is formed, through which the solution may flow.There are many different types of vessels, and systems used to hold the resin, but it is not the intention of this chapter to describe them all, but to describe two methods used in Elliot Lake. These are the ""fixed bed"", and ""moving bed"" systems, the condition of the bed during normal operation signifies the name of the system.Chemical and Physical Characteristicslon Exchange ResinThe resin used is a strange base Anionic resin, semi-rigid, and spherical in shape. The size of the wet resin is approximately 9007o between 20 and 40 mesh. Physically the beads of resin are broken early, but some have lasted over 15 years and are still in use."

Jan 1, 1989

By Wei Wei

Mining induced ground movement and/or stress redistribution could cause ground instability issues. This is particularly true when the extraction of large stopes is done with one or two large production blasts. Often enough, it is the nearby mine development like haulage drifts and cross cuts that are influenced the most by production blasts. Proper and timely mitigation of ground control issues due to stress redistribution is required. This is usually done by drift rehabilitation involving the installation of secondary support system in the affected areas of the mine development which include; slashing, wire mesh, and in some cases the use of shotcrete liners. It is imperative that such rehabilitation be implemented to the mine infrastructure in a timely manner in order to avoid aggravated ground control problems and production delays. If the real time performance of the support system is captured, it would be possible to determine the timing for rehabilitation job. Birchtree Mine in Thompson, at the Vale Manitoba Operation, has begun mining the 84 Deep Orebody. One of the identified risks is the stability of the crusher room under mining induced stress redistribution. It is proposed to use the U-Cell technology to monitor the primary support system performance (rebar bolts and extension bolts) and monitor the real time performances of the bolt axial loads. The U-Cell technology is a 7-inch long, coupler load cell that is screwed onto the threaded portion of a rock bolt prior to installation. Rehabilitation in the vicinity of the crusher area where U-Cells are installed is recommended when the bolts have reached 70% of their yielding capacity. Catastrophic ground failure can be avoided by adding secondary support in a timely fashion. This paper presents a case study at Birchtree Mine in Thompson Manitoba, where the performance of primary ground support system is monitored and recorded during production.

Jun 1, 2012

By C. S. Touchard, F. Bourgeois, L. Cassayre, Julcour-Lebigue C.

Developing a hydrometallurgical process that can overcome the refractory nature of chalcopyrite (CuFeS2) to leaching still eludes the minerals industry, despite major research efforts spanning decades. The several leaching experiments of this ore in sulfuric acid tend toward the same conclusion that the precipitation of elemental sulfur or iron containing species are the main dissolution inhibitors. Describing both the electrolyte composition and the various solid phases in equilibrium for the Fe-H2SO4-H2O system is essential to overcome this issue and to find an operating window. According to the thermodynamic models and to the thermodynamic data, we demonstrate, in this study, the need to use the Specific ion Interactive Theory (SIT) model to describe complex electrolytic systems through a limited number of parameters. Hence, the binary interactions for our case study have to be defined and estimated. This work develops a methodology to determine these parameters of the SIT model up to 90°C and an acid concentration of 1 mol/kg from published data for H2SO4-H2O and Fe(II)-H2SO4-H2O sub-systems or from new experimental data for the Fe(III)-H2SO4-H2O one. This method will eventually be applied to copper systems to lead to a thermodynamic description of the complete CuFeS2-H2SO4-H2O system. INTRODUCTION A leaching process consists in the dissolution of a solid phase into an aqueous medium in order to extract compounds of interest. It is a key step in the hydrometallurgical processes used in the primary production and recycling of metal components. One of the main leaching issues is the formation of passivating layers on the surface of solid particles, whose consequence is a partial or total hindrance of the dissolution. The leaching of chalcopyrite (CuFeS2) in sulfuric acid is a prime example. No industrial solution for the atmospheric pressure leaching of this ore has been developed to date because of passivation phenomena caused by the formation of elemental sulfur or iron-containing precipitates on the surface of the particles (Li, Kawashima, Li, Chandra, & Gerson, 2013). In the 1970s, the Pourbaix diagrams established for the Cu-Fe-S-H2O system at 25°C for low concentrated solutions (Garrels & Christ, 1965; Peters, 1976) agreed that copper and iron are fully dissolved at high potential and in acidic medium (pH < 4). However, they neglected the many stable solid phases that can form in these conditions. In addition, the Pourbaix diagrams of chalcopyrite in water, calculated with two recent databases (FactPS and Thermoddem 2017) associated to FactSage and PhreeqC softwares respectively, show large discrepancies at 75°C (Figure 1). Indeed, at high potential, FactSage predicts the formation of goethite FeOOH at a pH value of 1, while PhreeqC predicts the formation of jarosite (H3O)[Fe3(SO4)2(OH)6] for pH greater than 2.5.

Jan 1, 2019

By Y. Chunhua, L. Chunsheng, W. Sheng

"Countercurrent solvent extraction is the dominant industrial rare earth separation method. For the rare earth separation, with low separation factors and multiple components, designing and optimization plays an important role in reaching product quality and reducing separation plant costs. Based on the theory of countercurrent extraction, cost-efficient methods, such as third-outlet separation and hyperlinked extraction processing, have been introduced following computer simulation. The consumption and fixed investment of industrial practice are compared, by which advantages of the optimized rare earth separation process are indicated. INTRODUCTIONThe rare earths (RE) have outstanding optical, magnetic and electric properties in advanced material applications and have therefore received much international attention in recent years. Liquid-liquid extraction is the major industrial RE separation method and is widely used in the industry. Supported by the government and with collaboration from the institutions and enterprises, China has made great progress in RE separation, and has become the dominant supplier of separated RE products. Complicated by multiple elements and low separation factors, careful design of RE separation processes is vital for the quality and cost of production. The theory of separation is the key to basic of flowsheet design and industrial applications.BASIC SEPARATION PROCESS AND THEORYGeneral ProcessAcidic extractants such as P507, P204 and naphthenic acid, are the most popular extractants in modern RE separation industry. In the general separating process, the extractant is saponified with a base, then ion-exchanged with RE solutions, thereby to provide stable and high RE loading in the extractant to fulfill the requirement of production quantity and quality. The RE-loaded extractant is then countercurrently extracted and scrubbed with RE solutions and the RE element thereby is purified. After the countercurrent extraction process, the RE-loaded extractant is stripped with acid to obtain an aqueous RE product, and prepare the extractant for recycling (Xu, 1995)."

Jan 1, 2012

By L. Voisin, E. Díaz, V. Montenegro, W. Kracht

Grinding media is of great concern in the mining industry mainly because its consumption represents an important part of the costs during mineral processing and consequently, of the total mining business OPEX. In addition, grinding media consumption impacts directly on flotation performance through negative contamination by corrosion, affecting the pulp chemical potential, complicating the understanding and control of the process, as galvanic interactions between mineral species also occur. In addition, during the process there is also a physical consumption of the grinding media through erosion and impact. In both cases, mineralogy has an important role because pulp abrasion power, chemical reactivity, rheology, hardness and other variables depend on the minerals contained in the pulp and their interactions. In the present study, a geometallurgical and phenomenological model, which describes the grinding media consumption and its relationship with mineral hardness expressed by Bond Work Index, was obtained based on advanced mineral characterization techniques such as Hylogger3TM, X-ray diffraction, X-ray fluorescence and experimental grinding tests using a laboratory mill applied on Chilean copper pulps. The results obtained show that pH has an important effect on grinding media consumption, because corrosion varies with hydrogen ions availability. Also, mineral hardness depends on mineralogical composition, but textural analysis must be performed to have a better description of this property. Finally, minerals present in a sample define the grinding media consumption mechanism, because a sample with harder minerals and a greater value of Bond Work index is capable of protecting grinding media from impact wear, while a sample with lower hardness but with a big sulfide minerals content would be more aggressive with grinding media because corrosion is more important in this case. The geometallurgical model obtained is capable to relate the grinding time, mineral hardness, content of sulfide minerals and grinding pH to estimate the grinding media consumption.

Jan 1, 2017

By J. R. Morris, A. E. Ball, G. W. Kuzyk

"AECL Research has constructed an underground laboratory for the research and development required for the Canadian Nuclear Fuel Waste Management Program. The experimental program in the laboratory will contribute to the assessment of the feasibility and safety of nuclear fuel waste disposal deep in stable plutonic rock.In 1988, AECL extended the shaft of the Underground Research Laboratory (URL) from the existing 255 m depth to a depth of 443 m in cooperation with the United States Department of Energy (USDOE). The project, which involved carrying out research activities while excavation and construction work was in progress, required careful planning. To accommodate the research programs, full-face blasting with a burn cut was used to advance the shaft. Existing facilities at the URL had to be modified to accommodate an expanded underground facility at a new depth. This paper discusses the design criteria, shaft-sinking methods and approaches used to accommodate the research work during this shaft extension project.IntroductionThe Underground Research Laboratory (URL), a major geotechnical research facility, has been developed by AECL Research, 120 km northeast of Winnipeg, Manitoba. The URL is part of the Canadian Nuclear Fuel Waste Management Program (CNFWMP), which is assessing the concept of nuclear fuel waste disposal in a vault deep in stable plutonic rock of the Canadian Shield (Hancox, 1986). The URL provides a representative environment to conduct a wide variety of geotechnical research relevant to nuclear waste disposal. Extensive characterization and monitoring programs were carried out prior to construction and will continue during operation. The operating phase experiments began in 1989 and will continue until the year 2CXXl (Simmons, 1990). Figure I shows the present extent of the URL facilities and the proposed future development."

Jan 1, 1991

By L. H. Rajala, K. H. Singh

"This paper presents the results of a detailed feasibility study carried out to investigate whether a low-grade deep underground mine of Falconbridge Nickel Mines Ltd., closed since 1975, could be made more productive and profitable by the introduction of new mining technology. For this purpose, recent advances in mine design and development concepts, larger and better designed machines, such as hydraulic drills, high-pressure down-the-hole machines, LHDs, new blasting concepts, more efficient and improved stoping methods, and ground control technology were considered. Technical and economic analyses incorporated the latest computer-based techniques. The mine was reopened in 1979 and the paper concludes with an assessment of actual progress and performance compared with that planned and forecast.IntroductionThe East Mine orebody, located between the Falconbridge Mine and Inco&apos;s Cryderman Mine in the Sudbury District of Ontario, has been in production since 1956. From 1956 to 1978, about 5.6 million tons of ore had been mined from this ore zone. The ore body is low grade and was developed as a cut-and-fill operation. Due to high operating costs, the mine has been shut down several times during economic downturns. The latest closure was in 1975 due to a lower demand for metal.In 1978, investigations were initiated to assess the economic and technical feasibility of mining this ore using new developments in mining technology. In this study, consideration was given to the application of bulk mining methods with a potential for higher productivity, trackless development utilizing efficient LHD machines and hydraulic drills, new blasting and fragmentation concepts, and new ground control technology. Advanced computer techniques, such as finite element, for mine design and rate of return with discounted cash flow analyses for the economic comparison- of various mining options were utilized for a rapid and comprehensive assessment during the feasibility stage."

Jan 1, 1981

By R. D. H. Wigmore

"The title of this paper probably sounds quite simple and self-explanatory. The problem, however, was not a simple one, and proved somewhat baffling and expensive over a period of years. After outlining the problem, and the methods which were used to overcome it, we will present our solution, or perhaps it would be more accurate to say the partial solution which we reached.We have in the cyanide circuit at Upper Canada two Dorr Single Tray Thickeners with 30 ft. diameter wood stave tanks 12 ft 4 1/ 2 in. deep. In the years prior to 1948, when the tonnage was 250 to 280 tons per day, two stage thickening was practised. As the tonnage was increased to 450, 500, and finally 560-600 the thickeners were used in parallel.Some settling problems were encountered, and in those days the means to combat these problems were very few. The only remedy was to dump in pounds and pounds of lime. Then along came a few reagents, and the writer remembers one in particular, - 11 Carboxel11 (carboxymethlycellulose). When water or solution was added to this reagent, the result was a gooey mass somewhat resembling tapioca. One drawback was that it stayed in this state, and didn't go anywhere. A method was finally developed of containing the mass (or mess) on a fine screen, and dissolving some of it was a fine spray of solution. The only thing the writer recalls was that it was not a very effective settling agent.Shortly after this time, along came the new flocculents, first a few, and then many, and our settling problems were over.But when the settling problem was solved at Upper Canada, some other problems were creeping up on us."

Jan 1, 1965

By Xiaolin Cheng, A. J. Sinclair

"Norm calculation procedures originally designed principally for igneous rocks are very rigid in their application and, in general, do not utilize important alteration minerals. For instance, volatile components are essential constituents of many metasomatic rocks but either are not used or are not used effectively in determining normative minerals by the CIPW norm or Niggli-Barth norm procedures. Our approach to determining norms for metasomatic rocks allots all major, minor and volatile constituents to a set of standard normative minerals which are commonly observed as products of hydrothermal alteration. A useful procedure is to have a metasomatic norm approximate the mode as closely as possible. Petrographic information helps to provide the necessary mineralogical constraints. With the recognition of an immobile component and knowledge of sampling and analytical errors in lithogeo chemical data, it is possible to recast norms into amounts of alteration minerals relative to a given amount (100 grams) of parent rock. Combining these results with the calculations of absolute loss or gain of individual chemical constituents and considering errors (e) for an appropriate confidence level, an overall (net) material exchange equation can be presented as follows:<equation>where all items have extensive units (e.g., grams). The model includes the initial and final mineralogy of rocks (evident in the field) as well as gains and losses of specific elements. Only those constituents whose calculated losses and gains are significantly different from zero are retained in the above model, and only the normative minerals with abundances significantly different from zero are included in the model (equation). One advantage of the chemico-mineralogic model is that parent rock and product are modeled in mineralogical terms that are familiar to and easily usable by exploration geologists."

Jan 1, 1995

"Since all gold mills must sooner or later be cleaned up for permanent shutdown it was felt that a record of what was done at one mill might be of some help to those who will have to do the same job in the future,In cleaning up the mill of Delnite Mines Limited, I had an advantage that most mill superintendents will not have in that I started up the mill and was there until it was shut down, It was also known for two years approximately when the shutdown would be and for a year almost the exact time. This, of course, made careful planning possible and enabled me to get advance information that wouldn't have been available had the shutdown come unexpectedly,Early in 1964 calculation of ore reserves and the known number of working places available indicated that the mine would run out of ore sometime in August or September but not later than October, The time of course would vary with the number of competent miners that could be retained until the shutdown. Since the mining method used exclusively on the ore then remaining was cut and fill, it was known that once mining operations ceased it would require at most two days to crush and grind the last of the ore.In March 1 964 I took samples of the concrete floor under the precipitation presses, in the flux room and furnace room of the refinery and from the assays obtained proved that there would be no profit in breaking up the concrete to recover the gold from it, Samples taken from the top half inch of the concrete floors assayed less than 0, 10 oz per ton,"

Jan 1, 1966

By A. Gillis, J. Keyes

"This is a prelirr1inary report on automatic control at East Malartic Gold Mines.After installation of the cyclones in the East Malartic grinding circuit, the interest was aroused in the automatic control system for the circuit. Investigations were made as to the possibilities of such an installation. This resulted in a preliminary survey of the circuit by Milltronics Ltd and an analysis of the circuit by Mines Branch personnel. A study of the investigation and analysis indicated that a cost reduction and improved efficiency could be expected by the installation of an automatic control system in the grinding circuit. It was also indicated tl1at such installation should pay for itself within a year. This was the point that sold management on such installation. The need of three operators was expected to be eliminated .The installation was to consist of a central control panel, microphoncs on each mill, regulation of feed rate, pneumatic valves for addition of solt1tions, density control of the cyclone overflow, which is a grinding circuit product, rod mill feed box plugging detector and a conveyer weightometer for tonnage indication and control.As well as the elimination of one man per sl1ift, other benefits which were to be received but unable to estimate were: 1) More tonnage per clay by operation of the mills at the proper capacities. 2) Lower grinding costs. Less under-loading should result in less steel wear and lower pumping cost. In the condition of overloading, a coarser grind is obtained resulting in greater impeller and liner wear. The overloading and underloading showed up on the n1icropl1oncs. 3) An improvement in the recovery as a result of less over-load. The tailings loss from a coarser grind are not as frequent."

Jan 1, 1965

By Ayako Iwakoshi

Highly concentrated pastes of gold nanoparticles were successfully produced by use of a special kind of protective polymer and a mild reductant. Solid part of the pastes consists of up to 85wt% of gold nanoparticles, 10~30 nm in diameter, and residual protective polymer. This component can be diluted by any kinds of solvent at arbitrary rates. Electronics, optics, catalysts, colorants and surface metal coatings are possible application fields. 1. Introduction Noble metal nanoparticles are of interest in a variety of fields ? such as colorants, metal coatings, electronics(1), optics(2), and chemical catalysis(3). Especially, in the color field, the gold nanoparticle has been known as an aesthetic red colorant for stained glass and fine glassware, such as Venetian glass. The mechanism of coloring is attributed to surface plasmon absorption of gold nanoparticles(4,5). The gold nanoparticle in stained glass shows very clear red color, which is very durable for hundreds years. On the other hand, the red color of organic pigment in paint films often fades away within several years. We intended to reproduce the elegant and stable coloring of stained glass in paint films. In order to color a very thin, 20~50?m, paint film like stained glass, production of highly concentrated dispersion of gold nanoparticle is necessary. To achieve this, there were two issues to be overcome. One is how to prevent the coagulation of gold nanoparticles in highly concentrated solution. So far, several methods to prepare gold nanoparticles(6,7) were reported. But only a few methods succeeded to stabilize the gold nanoparticle dispersion at higher concentration than ppm order. The other is controlling of the particle size, this is because the color of gold nanoparticles is very sensitive to the particle size. Only when the particle size lies around 10 nm, the suspension exhibits red color like stained glass.

Oct 1, 2003

By Xiaolin Cheng, A. J. Sinclair

"Abstract - Norm calculation procedures originally designed principally for igneous rocks are very rigid in their application and, in general, do not utilize important alteration minerals. For instance, volatile components are essential constituents of many metasomatic rocks but either are not used or are not used effectively in determining normative minerals by the CIPW norm or Niggli-Barth norm procedures. Our approach to determining norms for metasomatic rocks allots all major, minor and volatile constituents to a set of standard normative minerals which are commonly observed as products of hydrothermal alteration. A useful procedure is to have a metasomatic norm approximate the mode as closely as possible. Petrographic information helps to provide the necessary mineralogical constraints. With the recognition of an immobile component and knowledge of sampling and analytical errors in lithogeochemical data, it is possible to recast norms into amounts of alteration minerals relative to a given amount (100 grams) of parent rock. Combining these results with the calculations of absolute loss or gain of individual chemical constituents and considering errors (e) for an appropriate confidence level, an overall (net) material exchange equation can be presented as follows:SMineralparent rock ± e + SConstituentgained from solution ± e= SMineralaltered rock ± e + SConstituentlost from wall-rock ± ewhere all items have extensive units (e.g., grams). The model includes the initial and final mineralogy of rocks (evident in the field) as well as gains and losses of specific elements. Only those constituents whose calculated losses and gains are significantly different from zero are retained in the above model, and only the normative minerals with abundances significantly different from zero are included in the model (equation). One advantage of the chemicomineralogic model is that parent rock and product are modeled in mineralogical terms that are familiar to and easily usable by exploration geologists."

Jan 1, 1995

By R. W. Pugh, S. L. Ma

"High carbon rods are typically used as the grinding media in rod mills. Usually an AISI I 090 grade of steel is used which provides the high hardness needed for abrasion resistance and sufficient toughness to prevent rod breakage.Work to improve performance in the past has mainly concentrated on increasing the hardness for improved abrasion resistance. This has been accomplished by adding alloys to the steel which uniformly increase the hardness across the rod section.However uniformly increasing the hardness of the rod produces a more brittle product and at high hardness l1evels can lead to rod breakage problems. Heat treatment processes can be used to selectively increase the surface hardness to high levels while maintaining the core at lower hardness levels to give a product that wears slower without breakage. AltaSteel has developed and mill tested a higher hardness heat treated grinding rodThis paper describes the development of a simple model to predict performance improvement with different hardness profiles and the AltaSteel heat-treated grinding rod process. Mill characteristics of the Endako operation are summarized and predicted performance improvements based on hardmess are compared to the approximate 25% achieved in trials running since July, 1991 at this mill. Early results of other mill trials are also presented.INTRODUCTIONAltaSteel, in Edmonton is a major supplier of grinding media. We have a strong desire to continually increase the quality and performance of our products and thereby improve the efficiency of our customers' processes. In the area of grinding rods, we wanted to produce a product with a significant improvement in wear rate. Second to energy, rod consumption usually represents the next highest cost in processing. This paper presents our development of a heattreated grinding rod that has reduced consumption by about 25% in trials to date."

Jan 1, 1993

By S. Caron, M. Bourassa, J. Châteauneuf, L. Tardif

"Since many years, the Yvan-Vézina gold plant custom mills and processes different ore types that show different behaviors. Because of this, cyanidation control is more complex than for a typical milling operation. In 1992, a Cyancor™ on-line « free cyanide » analyzer has been installed for monitoring and optimizing cyanidation. This implementation significantly reduced cyanide consumption for the overall cyanidation process. In order to further reduce cyanide costs, an automatic control strategy has been implemented to decrease fluctuations of« free cyanide » from their set points.This paper outlines the major steps of the project: process control audit, control strategy development, implementation and running-in period. Control strategy features include data filtering modules, adaptive PID algorithm and set points management modules are also presented. Finally, the strategy efficiency is illustrated with load-disturbance responses.IntroductionLocated in northwestern Quebec, the Yvan-Vézina plant has an average capacity of 1300 t/d using carbon-in-pulp technology. In 1991, the Yvan-Vézina gold plant was processing three types of ores (Beauchemin, Mouska and Silidor mines) and a pyrite concentrate (Beliveau mine). A cyanide reduction program was then undertaken to reduce « free cyanide» fluctuations <6>. To reach this objective, the optimum cyanide concentration was determined for each ore, a continuous monitoring method with the Cyancor™ on-line analyzer was developed and a tighter control of cyanide addition was applied. These modifications to the leaching practice significantly reduced cyanide consumption.After a while, it was observed that regulation of « free cyanide » concentrations could still be improved by the use of an automatic control strategy. Yvan-Vézina and CRM began collaborating in 1995 to develop and implement such a strategy. Results show that main disturbances of the circuit (e.g. ore mineralogy and pulp feed rate) can be significantly overcome in order to reduce their effects on the leaching operation."

Jan 1, 1998