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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

By R. A. Gannicott

Trend surface analysis was used to investigate the geochemical dispersion patterns of Si, Ai, Fe, Mg, Ca, Na, K, Ti and Rb in the footwall of the Seneca massive sulphide prospect in southwestern British Columbia. Surfaces for various element ratios were also produced to see if the distributions of the elements are related to each other. Trends developed by the elements redistributed during hydrothermal alteration may be difficult to detect for various reasons, such as too few and widely separated sample points, random analytical errors or local variations in rock chemical composition that are not related to regional trends. Trend surface analysis is useful to distinguish regional trends from local fluctuations. The computer program used in this study is capable of calculating surfaces up to the 6th degree polynomial, but provides for automatic termination when the variables in the equation for successive surfaces become effectively collinear. With the relatively small number of data points used (21 samples) in this study, such termination occurred after the quadratic surface. Results show that, at the Seneca prospect, Mg and K increase, and Na and Ca decrease, toward a common centre which corresponds closely with the best drill-core intersections of ore. The centre is interpreted as a volcanic vent and as the source of mineralization . Quadratic surfaces for element ratios show that K/Ca decreases and Fe/Mg increases away from this vent. Thin-section and X-ray diffraction analyses indicate that these variations reflect sericitization of plagioclase and an increase in the Mg content of chlorite near the vent. The mineralization , rock types and element dispersion patterns at the Seneca prospect are similar to those reported for volcanogenic massive sulphide deposits at Bathurst, New Brunswick, and in the Hokuroko district of Japan.

Jan 1, 1979

By L. Hutton, S. W. Colley

"The release of soluble salts of base metals from acid mine pits and in the waste water from metal refiners is an avoidable source local pollution and contamination. Tightening of the regulations controlling natural resource extraction and industrial wastewater discharge is mandating the removal and recovery of metals from waste streams, and the remediation of contaminated sites. There is an economic incentive in recovering the valuable copper and nickel, as the value of the recovered metal can offset remediation costs and for high flow waste streams can be a source of income. Extraction of metals from waste streams by conventional Ion Exchange and chelation resins is widely practised, but has limitations on applicability in complex and dilute feeds due to the structure and properties of polymeric resin beads. Composite Advanced Ion Exchange (AIX) materials have been developed for the recovery and purification of base metals from base metal mining and metal processing industries. A silica-composite based resin has been developed for the selective extraction of copper from high iron containing feeds. This resin can be eluted with sulfuric acid yielding a copper stream suitable for return to solvent extraction or to electrowinning. We describe the development and application of the resin and process to two acid mine drain feeds of varying copper and iron concentrations, and show that the copper concentration can be considerably upgraded even at small scale with a final metal content of >95% copper.INTRODUCTIONWaste water with high sulphate concentrations, low pH and containing complex and variable mixtures of metals is an inevitable product in the mining, extraction and metal refining industries. One problematical water source is Acid Mine Drainage (AMD) which in addition to the metals of interest also contains a wide range of contaminating elements. Purge streams from metal refining are less complex in composition but contain significant quantities of the value metals. The typical treatment of such waste streams is treatment with lime to increase the pH of the water, precipitating the dissolved metals and sulphate as a sludge of mixed metal oxides/hydroxides and sulphates. The process is effective in producing a water stream that can be safely discharged but if there are significant concentrations of value metals such as copper, nickel, zinc then there can be a considerable loss of metal value."

Jan 1, 2016

By D. T. Smith, S. J. Strohmayr

Originally developed as a step change in ultrafine grinding efficiency, the IsaMill™ has made inroads into conventional ball mill and tower mill mainstream grinding duties during the last 5 years - beginning with the Anglo Platinum mainstream grinding projects in South Africa. At the 2006 SAG Conference, plant testwork on the incorporation of IsaMill™ technology into the McArthur River (Northern Territory, Australia) Pb/Zn primary grinding circuit was reported. The IsaMill™ has now become an integral component of that circuit, treating up to 1mm top size feed and directly producing P80 45 µm rougher flotation feed. Two 1.1 MW IsaMills™ are now used in this duty contributing to a 27% increase in overall plant throughput and a reduction in rougher feed size distribution. In this paper, we report on the current state of development and performance of the IsaMill™ in the primary grinding duty at McArthur River and also consider future directions.

Jan 1, 2012

By K. Sawamukai, S. Ogasawara, D. Umenai, T. Tsuruta

"Removal of cobalt, strontium or cesium ion from the aqueous solution containing each metal ion only using microorganism was examined. Arthrobacter nicotianae which had a high ability to remove cationic metal ion was used for the removal of each metal. The removal of cobalt, strontium or cesium using A. nicotianae cells was affected by the solution pH, concentration of metal ion, and cell amount. The effects of above mentioned factors on the removal of each metal and time course of strontium from the solution containing each metal only using A. nicotianae cells were reported in this paper. INTRODUCTIONRadioactive elements, such as cesium, iodine, strontium, plutonium, barium, cobalt, lanthanum, yttrium, and tellurium, were detected around Fukushima Daiichi nuclear power plant, which was damaged by the magnitude 9.0 earthquake and the tsunami followed.The removal of radioactive elements from contaminated sources is a worthwhile subject to investigatein terms of environmental control. Research efforts have been especially concentrated on studying microorganisms that remove uranium including bacteria (Andres et al, 1993, Hu et al, 1996, Marques et al, 1991, Strandberg et al, 1981), actinomycetes (Byerley et al, 1987, Friiss and Myers-Keith, 1986, Golab et al, 1991), fungi (Byerley et al, 1987, Galun et al, 1983a, Galun et al, 1983b,Tsezos and Volesky, 1981, White and Gadds, 1990) and yeasts (Strandberg et al, 1981, Schmate II et al, 1978).We have investigated removal and recovery of uranium from aqueous systems using microorganisms isolated from uranium mines. We identified some strains of bacteria with extremely high uranium removing abilities (Sakaguchi et al, 1996), and thus, the microbial biomass may be considered as an adsorbing agent for the removal and recovery of uranium and heavy metals present in aqueous systems around Fukushima Daiichi nuclear power plant.In the present study, we screened various species and strains of bacteria, actinomycetes, fungi, and yeasts for their ability to adsorb uranium (Tsuruta, 2002). Basic features affecting uranium adsorption?co-existing cations and anions, cell amounts, pH, and the adsorption time course?by Arthrobacter nicotianae cells, which adsorbed the largest amount of uranium, were also investigated. In addition, we examined the removal of an other actinoid element, thorium ion, which may be present with uranium in refining effluents.In this paper, the removal of cobalt, strontium, or cesium from the solution containing each metal ion using A. nicotianae cells is discussed."

Jan 1, 2012

By Nural Kuyucak, Bohumil Volesky

"Extensive screening revealed a seaweed (alga) biomass type which in its non-living state possesses a very high cobalt sequestering capacity comparable to that of activated carbon and the ion-exchange resin currently used in the cobalt production process. Performance of the new bio-sorbent material was studied by examining its equilibrium metal uptake isotherms generated under different solution conditions such as initial cobalt concentration pH, temperature, and the presence of selected cations and anions. The rate of cobalt uptake was determined, which is a crucial parameter for recovery process design. Almost all cobalt sorbed can also be desorbed with a solution of CaCI2. The bio-sorbent material can be used repeatedly in the sorption-desorption cobalt concentration process. IntroductionIt has been well documented that certain types of microbial biomass, living or non-living, possess a high potential to sequester and accumulate inorganic ions present in aqueous solutions. Metal concentration by microbial biomass from a solution is termed bio-sorption. This phenomenon is quite complex and includes adsorption of metals onto the surface of a microorganism and/or into the cellular structure in combination with ion-exchange, complexation, and/or micro-precipitation. Bio-sorption is generally considered to be a rapid physical/chemical process. The cell wall structure is porous and allows metal ions, as well as large organic nutrient molecules, to pass freely through. Polysaccharides of the cell wall could provide binding amino, carboxyl, phosphate and sulphate groups. In addition to these functional binding groups, polysaccharides often have ion-exchange properties. Sometimes, bivalent cations, such as Ca2+ or Mg2+, help the formation of ionic bond bridges between the negatively charged cell surfaces and positively charged cations in the solution, Proteins in the cell wall could offer functional groups and also offer peptide bonds to bind ions. Interactions between metal and the cell wall components are responsible for the sequestering of metals by way of bio-sorption. Many metals feature a complex solution chemistry and it is not always possible to determine what ionic species are actually present in the solution. The equilibria involved are dependent on pH, concentration, the anions present and other factors. The transport system for the ions are sometimes dependent on both temperature and energy. Biosorbent material could also be regenerated for multiple reuse."

Jan 1, 1988

By M. B. Greyver

The results of laboratory tests on iron precipitation from non-decopperized nickel anolyte are discussed. The parameters (pH, oxygen consumption and stirring speed) for iron precipitation from the anolyte, using the oxygen in the air, were determined. In the experiments conducted under optimized conditions, the residual concentration of iron in the anolyte after precipitation was 0.7-2.7 mg/L, and the copper and nickel losses to the solid phase were 0.05-0.07% and 0.05-0.16%, respectively. The filtration ability of the iron slurry obtained was 2 to 5 times higher as compared to that after chlorine oxidation and oxyhydrolysis. The leaching of the non-ferrous metals from the iron cake made using the separate nickel anolyte purification process was possible by dissolution in sulphuric acid. It was established that after cobalt precipitation from the copper- and iron-depleted anolyte, the precipitates obtained had lower ratios of Fe:Co and Ni:Co.

Jan 1, 2006

By Lionel C. Kilburn

"This geological engineering method is based on jour main characteristics of mineral properties, viz; location: inclusion of valuable mineralization; inclusion of geophysical and/or geochemical targets; and inclusion of geological targets. These are subdivided into a total of 19 subcategories, which are used to determine the value of the property.The nineteen subcategories are prioritized and assigned relative value factors from 1.3 to 10. Value of each mineral claim unit is determined by applying the appropriate subcategory factors to a base value of $400per 16.2 hectare unit. Property value is calculated by totalling the values of such individual claim-units.The boundary between ore grade and sub-ore grade must be estimated for each property under valuation, thereby making the method sensitive to mineral commodity prices.A clear and disciplined sequence of decisions based on personal experience forms the basis of this method. The method utilizes all factors normally used to value a mineral property.IntroductionIt is generally accepted in the exploration industry that valuation of exploration properties is a subjective rather than objective process (Roscoe, 1986; Lawrence, 1988; Lawrence, 1989; Woodcock, 1985), and that it is greatly influenced by the experience and qualifications of the person who is doing the valuation. However, the significantly low degree of objectivity in mineral property valuation at this point in time invites effort to achieve a more quantitative engineering basis.Value of a mineral property depends basically upon metal prices, recoverable grades, mining and metallurgical practices, commodity supply and demand , and political-economic conditions, all of which vary with time. Therefore, any valuation is valid for only that point in time when it is made. Mineral deposits can decrease as well as increase in technical value with time."

Jan 1, 1990

By Ralph J. Holmes

"An accurate knowledge of the chemical, mineralogical and physical characteristics of ores and mineral products that are mined, processed and sold commercially is crucial to resource definition, effective resource utilisation, plant design, process control, metallurgical accounting and finally quality control to ensure that contract specifications are met and equitable payment is received for product sales. However, the responsibility for sampling is often entrusted to personnel who do not fully appreciate the significance and importance of collecting fully representative samples for analysis, and they seem satisfied as long as some material is collected and returned to the laboratory for analysis. Furthermore, sample stations incorporated into the design of new plants are often the first casualties when cost cutting exercises commence. There is really little point in accurately analysing samples if they are not representative in the first place, because the resultant analyses can be seriously biased and the effort taken to carefully analyse such samples is largely a waste of time and resources.Ultimately, a poor knowledge of the characteristics of ores and mineral products limits the ability of mining companies to optimise the life of ore resources and plant performance, and failure to meet final product specifications can have disastrous consequences, including price penalties and more seriously loss of sales contracts and significant revenue losses due to poor sampling practices at the point of sale. Consequently, it is critical that sampling is given the attention it deserves as the first important step in the quality measurement chain. The golden rule for correct sampling is that all parts of the ore, concentrate, slurry or other material being sampled must have an equal opportunity of being collected and becoming part of the final sample for analysis."

Jan 1, 2016

By A. Alfantazi

Recently, titanium and its alloys have been the materials of choice for the liner and internal components of autoclaves used to extract Ni and Co from laterite ores. There have been many corrosion incidents ranging from localized attacks due to scale formation or welding, to damage caused by pockets of concentrated acid. Most of the literature focuses on methods to avoid the corrosion altogether. Little has been published to increase awareness of the chemistry at these conditions. For this paper, a literature review of the thermodynamics of titanium was undertaken to decipher the slew of information available. E-pH diagrams were constructed from select data and compared with the results of electrochemical experiments. Since nickel laterite leaching takes place in sulphuric acid, and in many cases chloride concentrations are very high, the Ti-H2O, Ti-Cl--H2O and Ti-SO4---H2O systems were considered.

Jan 1, 2004

By Alexander Smith

Surf Point and Edye Pass mines are on the northwestern part of Porcher island; 25 miles southwest of Prince Rupert. During the 1930's they produced about $750; 000 in gold from ore averaging better than one-half ounce a ton. The deposits are quartz veins; containing auriferous pyrite; concentrates average about 8 oz. gold a ton. The veins occur in a quartz diorite; stock. Their distribution shows an apparent control by primary flow structures; for the principal deposits lie on the axis of an arch of flow layers. The technique used in mapping the structures in the intrusive is that known as the Cloos method and described by Balk.

Jan 1, 1954

By Atulya Verma, Samantha Espley, Nashel Kalaka

Numerical modelling simulations of proposed mining sequences are used to evaluate mining induced stress concentrations and their migration associated with the progress of mining. This analysis is a standard practice for most prospective mining projects at various levels of feasibility study. The studies are usually initiated at the beginning of the mining cycle, on a global scale, and are maintained and updated throughout the life of mine (LoM) to identify or address local issues and the required remedies as and when needed. Developments in numerical modeling techniques along with advancements in computing technology and data storage/management capacity have given rock engineers access to a huge volume of data that needs to be analyzed and assessed. The most common approach to numerically evaluate stress concentrations and migrations in underground mines is to select the points of interest in a given volume such as the back of an excavation or points within pillars around critical infrastructure, and plot the stresses or a derivative of stresses over time to represent life of mine concentrations and migrations of stresses. The problem with this approach is the sharp gradient of stresses close to excavation boundaries. Slight changes in the location of selected points can change the stress concentration and migration patterns substantially and all generalized statements about LoM risk can be challenged in one way or another. For global stresses, the most common current approach of data analysis is by viewing series of pictures representing stress contours. In this approach, it is easy to overlook some critical detail and/or be masked by personal preferences of contour/picture representation. To overcome the problem of representing and analyzing huge volume of stress simulation data, the authors, through their experience at different mining operations, developed a volume-based technique to reliably evaluate mining-induced stress concentrations and migrations. The volume-based approach is for risk-based assessments of adjacent regions in the rockmass, in and around planned stoping excavations. The volume of interest is the entire ore body that is planned to be mined, but it could be just a part of the ore body depending on the specific use case. The risk identifiers are the induced stresses as compared to the strength of the rockmass. Over the LoM, the risk identifiers are tracked versus the corresponding excavation ratio of the zone. This approach is very effective in identifying the stages of mining that are contributing the most to the mining induced stress risk and the results can be used for proactive planning and mitigations measures such as alternative mining sequences, or stope sizes, or extraction methods. The approach has also been very successful in application at mature mines, particularly in assessing the re-initiation of mining in zone that has been dormant for some time. The volume-based approach allows for an assessment of the current state of the rockmass and the identification of future risks when planning resumption of mining activities.

Jan 1, 2023

By George P. Demopoulos

In this paper the author will provide an overview of over 20 years of research & developments in the area of hydrometallurgical arsenic immobilization that culminated recently in the industrial implementation of the atmospheric scorodite process. The paper will consider various aspects of arsenic fixation in the non-ferrous metal industry from the iron-arsenic co-precipitation process employed to arsenic-bearing effluent solutions; to autoclave processing of arsenical copper and gold feedstocks and the fate of the in-situ formed iron sulphato-arsenate precipitate phases; the precipitation and stability of scorodite; the possible stabilizing role of mineral phases like yukonite, and the development of "scoroditeplus" processes employing novel encapsulation strategies. Emphasis is placed on the characterization and long-term stability of the various forms of arsenic-immobilized phases under either oxic or anoxic conditions over a wide pH range and the establishment of critical links between process parameters and hazardous material stability, contributing thus to advancement of new generation safe and sustainable waste management technologies.

Jan 1, 2014

By M. Kalin

Tailings deposits are frequently the source of ground water contamination due to the transport of contaminated tailings pore-water. If amendments to tailings covers could be made to facilitate a precipitation reaction and halt or reduce the generation of acid in pyritic tailings, the quality of pore-water quality would be improved which would in turn reduce the production of contaminants. The effects of phosphate wastes, added to base-metal mine tailings in Newfoundland, Canada, were tested. Laboratory and field experiments determined the effects of different mixing ratios of phosphate wastes to tailings volume (1:4, 1:8, 1:12 and 1:20, dry weight) for a total period of 3.2 years. The addition of phosphate at ratios of 1:4 to 1:12 substantially increased the pore water pH, and reduced both acidity and Zn concentrations. These results suggest that addition of phosphate wastes to tailings covers can reduce acidity generation and improve tailings pore-water quality.

Jan 1, 2004

By P. Rocque, S. Talebi

Although the measurement of blast vibration close to the blasthole is critical to the understanding of rock fragmentation mechanisms and blast damage in the rock masses, limited experience for such monitoring exists. Because much higher vibration amplitude and frequency ranges are expected in rock masses close to an explosive charge as compared to far field vibrations, different problems from those for the far field monitoring must be considered for near field blast vibration monitoring. Currently, guidelines for design of the near field blast monitoring systems do not exist. This paper describes the development of an integrated technique for vibration monitoring close to a blast hole, including selection and installation of transducers, design of a monitoring system and signal recording. A densified cement was designed for grouting accelerometers in order to match p-wave impedance between the rock and grout. The monitoring technique described has proven suitable for blast vibration monitoring within 2 m to 15 m of a blast hole having loading conditions similar to production blasts.

Jan 1, 1993

By R. Mohamad, J. Asfahani

Abstract - Radioactive characteristics of pits drilled in the Al-Sharquieh mine while prospecting for recent phosphatic resources have been investigated. The results indicate that phosphatic layers are characterized generally by high radioactive intensities (more than 800 c.p.s). The lithological section in the study area is very complex sedimentologically, and characterized by high faciological variation in all directions. The Schlumberger geo-electrical configuration with fine separation of AB/2 was successfully applied to determine lithological boundaries, and the resistivities of the layers of the lithological section, especially for thin layers. It was shown that the phosphatic layer resistivities increase or decrease as a function of associated material. As a result, two types of phosphatic layers have been geo-electrically distinguished. The first is characterized by high resistivity and relatively low radioactivity, which could be related to the rock phosphatic layers. The second is characterized by low resistivities and high radioactivity, which could be related to the sandy phosphatic layers.

Jan 1, 2000

By K. G. Wheeland, K. G. Byberg

The occurrence of a secondary, dust-fuelled explosion following blasting of sulphide ores has been reported in mines in many countries, including canada, the USA, Australia and South Africa. However there has been little effort to document the events and develop effective control technology. Following a detailed investigation of an incident at the Geco Di vision of Noranda Minerals Inc. , the company held a conference of interested parties in October 1986 to review the state-of-the-art and to agree on action. '!his paper outlines the causes and effects of such explosions, the key conference points and conclusions, and subsequent information-exchange and teclmology-developrnent activities.

May 11, 1988

By M. Xiao Bo

In recent years, there has been a heightened interest in the hydrometallurgical processing of sulfide ores and concentrates (especially copper sulfide ores and concentrates) mostly in the USA and Chile. Currently, hydrometallurgical operations account for about 30% of the primary copper production. In the present research, the leaching phenomena of IOCG (iron-oxide hosted copper-gold) ores and concentrates were studied. The IOCG ore, which is characterized as having a predominant amount of magnetite with fine chalcopyrite, is currently the center of attention for new copper resources. Heap leaching of IOCG ore is desirable because of its low cost. However, the leaching characteristics of the ores and concentrates and the mechanisms of copper leaching require investigation. This study defines the factors, which affect the leaching operation, such as the ORP, pH and oxidizing agents. Based on these results, the optimal leaching conditions are provided for pilot column leaching test and ultimately, commercial operations.

Jan 1, 2007

By O. Hall

DISCUSSION AT QUEBEC MEETING MR. A. V. CORLETT: With drill holes radiating from a common point, is loading carried to the collars, and do you undertake to distribute the powder evenly? MR. R. V. PORRITT: When the collars of the holes, particularly the diamond-drill holes, are close together, two out of three holes are loaded only to within six or seven feet of the collars, and the intervening holes are loaded close to the collars. When the collars are farther apart, the holes are loaded close to the collars. No spacers are used, and the holes are filled solid with powder, this applying particularly to the diamond-drill holes, except, of course, where the collars are close together and some holes are not loaded close to the collars. MR. J. G. L. McCREA: I would like to enquire in respect to the various efforts made to reduce the cost of diamond drilling to the lowest point, what is. the relative cost of the solid bit to the standard bit? It would seem that the solid bit has the higher cost. MR. PORRITT: The non-coring or solid bit gives a slightly lower diamond cost than the coring bit. With the coring bit, the greatest diamond loss is on the inside stones, apparently due partly to vibration, but mainly to the core blocking against these stones. This condition, of course, does not apply with the non-coring bit. Our experience is that the non-coring bit, which drills out a much greater area, has a diamond consumption slightly less than the coring bit. The non-coring bit is sturdier, and is far less liable to damage in starting holes and in drilling through cracked or broken ground.

Jan 1, 1939

To date, improved thickening of clay mineral dispersions presents major technological and environmental challenge to mining and mineral processing industry worldwide. Flocculant-assisted dewatering processes currently employed during thickening are far from being efficient, requiring further development and process optimisation for dramatic improvement. In this paper, recent studies carried out to modify (i) pulp chemistry, (ii) flocculation performance and (iii) particle interactions to significantly improve the dewatering behaviour of flocculated, model and plant smectite and kaolinite clay dispersions are presented. It is shown that pulp pH-mediated hydrolyzable metal ion hydrolysis and specific adsorption in tandem with high molecular weight flocculant and shear may synergistically act to significantly enhance the dewaterability of both clay mineral pulps. Furthermore, polymeric flocculant structure type is demonstrated to show clear links with floc shear sensitivity, and hence, flocculation performance and pulp dewaterability. The implications and relevance of the findings plant clay mineral waste tailings thickening operations are drawn.

Jan 1, 2006