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By Nickvinder Bhath, Johnson Matthey Plc, Jamie Baker, Daniel Kim, Jeff Lucht, Shijie Wang

"Precious metals (PM) in copper anode slimes are traditionally recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of precious metals, including relatively inert metals such as gold and platinum group metals (PGMs). In this paper, a new method to recover PGM from complex and difficult feed streams is described. Using a proprietary Advanced Ion Exchange (AIX) adsorbent which has a high selectivity for PGMs over other metals and can achieve high PGM mass loadings with a series of incredible pilot test data plus the business case generated from the study results are also presented in the paper.INTRODUCTIONPrecious metals in copper anode slimes are traditional recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of many metals, including relatively inert metals such as gold and platinum group metals (PGMs). Fully hydrometallurgical processes for extraction and recovery of gold and silver from copper anode slimes were employed in major copper refineries since 1995, which was first developed at Rio Tinto Kennecott Utah Copper.In Rio Tinto KUC process, the wet chlorination and gold solvent extraction were utilized to enable recovery of gold and silver as well as other metal compounds. The availability of water and the interaction and amenability of gold processing in water-based solution makes it possible that gold and silver are produced in only five days, compared with a traditional pyrometallurgical process that took 45 days. Most copper refineries are still following the tradition, but the use of hydrometallurgical technologies is increasing as the world demand for metals increases, energy utilization, and environmental viability."

Jan 1, 2016

By W. E. Cockfield

THE object of this paper is to review recent geological work in the Cariboo district and to present notes on the recent development of mineral properties. The Geological Survey has done considerable work in the Cariboo district, extending over a period of years. In 1885 and 1886, Bowman (1) mapped the geology of a large area. In 1922 and 1923, Johnston and Uglow (2) mapped Barkerville area in some detail and prepared a report on the placer and lode gold deposits. In 1931 and 1932, Cockfield and Walker (3) mapped the Quesnel Forks area. In 1933, Hanson reported on Willow River area ( 4), and in 1934 made a detailed examination of part of the Barkerville area (5). In 1935, Lang commenced work on the Keithley area, lying to the southeast of the Barkerville area, and in 1936 published a preliminary re-port (6). The work on Keithley area was continued in 1936 by both authors of the present paper. As the results of the earlier work have been published, this paper will be concerned largely with Keithley area, that is, the part of the region lyinp between longitudes 121° 00' and 121° 30', and latitudes 52° 45' and 53° 00 . This area lies astride Cariboo (Swamp) river and extends north some 17 miles from Keithley, which is situated near the southern border of the map-area (see sketch-map). Points in the western part of the map-area are fairly accessible. A road extends from Barkerville to upper Cunningham creek, and from this a trail crosses Snowshoe plateau to Keithley. A second trail from this road leads to the lower falls on Cariboo river. From this road, a branch road leads to upper Antler creek, with a trail leading from this branch road to Keithley. Part of this western half of the area is made up of the Snowshoe plateau, which constitutes a gently rolling surface, at or above timber line, where trails are largely unnecessary.

Jan 1, 1937

By Feng Tianran, Lu Shijie, Shen Zhengchang, Han Zhibin, Tan Ming

"As a kind of non-metallic material, high-purify quartz sand has been widely used in many fields. Flotation is a popular way to process quartz sand. But it is in difficult position for flotation to get high-purify quartz product due to large amount of coarse particles contained in the feed. In this paper, a design principle of special flotation cell for high-purify quartz sand has been put forward base on ore property analysis and laboratory test, and the pilot scale special flotation cell has been developed to meet the requirement of the quartz sand flotation process. The special flotation cell for high-purify quartz sand is featured by middle positioned impeller, false bottom and draft tube, which could decrease the rising distance of mineralized bubble and strengthen the circulation capacity of the lower part of the flotation cell. Hydrodynamic study indicates that high air dispersion degree and strong lower slurry circulation could be produced by pilot scale special flotation cell, which is helpful to create a suitable hydrodynamic environment for quartz sand processing.INTRODUCTIONNatural quartz is a non-metallic mineral, which is widely used as raw material in multiple industry process (Shifu, 2006). High purity quartz, especially containing more than 99.9% silicon dioxide, is characterized by high temperature resistance, small thermal expansion coefficient, highly insulating and so on. The demand of high purity quartz has been rising along with social and economic development, now high purity quartz is widely used in the field of photovoltaic industry, electronic information, communications and aerospace industry.Quartz is a kind of main rocking-forming minerals in the nature. There are seven genetic types, such as natural crystal, quartz sandstone, quartzite, vein quartz, konilite, natural siliceous sand, granite quartz (Baolei, Shuilin, & Dianchao, 2012). The natural crystal is primarily used as raw material to refine high purity quartz, but it is not available for two reasons. On the one hand, the natural crystal is extremely expensive and poor in resources reserves, which can not satisfy the need of large-scale industrial production. On the other hand, the chemical component of natural crystal is instability, it may lead to low stable product performance in large industrial applications, and it is also difficult to achieve raw materials standardization. Therefore, there are a lot of studies to search for other technological methods to obtain high purity quartz from other genetic quartz types."

Jan 1, 2016

By T. Boiselle, C. Gielen, P. Henry, J. M. Bier

"Hydrometal is specialized in the production of zinc sulphate from complex secondary raw materials. Electric Arc Furnace (EAF) dust is one of the more interesting potential sources to produce zinc sulphate. In order to minimize waste quantities generated from EAF dust treatment, our R&D team has developed and patented a new process to recover the Fe contained in the dust as iron oxide product to be used and sold into the pigment market. The process is based on a specific reductive leaching step of the zinc ferrite contained in EAF dust, followed by a purification step to remove impurities (Ni, Cr, Cu...) and finally the controlled precipitation of the iron oxide. The aim of the iron precipitation step is to obtain the right shape and length of crystals in order to guarantee the right color and tinting strength of the pigment. The innovative aspects of the process results in the controlled oxidation of the iron to get the right crystal size and good purity material. The iron product can be valorized as red or yellow pigment often produced by the Penniman-Zoph process.INTRODUCTION A Few Words about HYDROMETAL Hydrometal SA (Engis, Belgium) is a subsidiary of Jean Goldschmidt International SA (JGI) in Brussels. JGI is mainly involved in metal trading activities (Goldschmidt, 1995). In 1985, JGI acquired the leaching circuit of a Belgian electrolytic zinc producer located in Engis, a few kilometers south of Liège, near the river Meuse and it was decided to name this plant: SA HYDROMETAL. Hydrometal is well connected by water, rail and road from its central location in the industrial region of Liege, in the heart of Europe. The company received in 1997 an additional license to process and recycle toxic and hazardous waste. Figure 1 shows a picture of the plant."

Jan 1, 2016

By Scott D. Long

"Abstract-Grass roots exploration has an emphasis on good precision at low (sub-economic) concentrations of an element, in order to identify "anomalies" which may lead to drilling targets. Although it is wise to have well-defined quality controls in place during early stage sampling, the control procedures at this stage tend to be rudimentary. When a deposit warrants detailed delineation, the need for accurate geological characterization and assaying of ore-grade rock must be supported by appropriate quality control procedures.As a project returns more promising results, and the likelihood of the project warranting a prefeasibility study increases, it is time to tighten quality assurance requirements and quality control protocols. Delays in instituting adequate quality control and verification procedures may lead to costly remedial actions that can also delay completion of the prefeasibility or feasibility study. Sometimes, as a project matures, the quality control and quality assurance aspects fail to keep pace with the changing nature of the work: an increasing emphasis on precise and accurate assaying of oregrade rock.A resource model is like a house of cards. The foundation of the house is the geological observations, the sampling methods and the geological interpretations performed upon those samples. Upon the sampling, which includes all the sub-sampling steps of sample preparation, rest the assay results. The quality of the assays can be no better than the quality of the sampling. Good assaying technique will preserve all biases and imprecisions introduced during sampling and sample preparation; it cannot remove them. If the sub-samples and/or assays are bad and must be redone, all the succeeding levels of the house of cards must also be rebuilt, or at least patched up.From geological observations, a geological interpretation is built, the quality of which is critical to the construction of an acceptable resource model. Geological elements are difficult to assess, and are not discussed here; they are dependent upon the expertise of the geologists involved. Geological knowledge contributes essential quality control elements to resource/reserve determinations (Sinclair and Postolski, 1999; Postolski and Sinclair, 1999).This paper consists of five sections: (1) overview of quality control protocols, (2) maintaining quality control of databases, (3) quality control of drill sampling, (4) optimizing crushing and grinding requirements, and (5) quality control of assay data acquisition."

Jan 1, 1998

Presentation Outline Introduction Deposit Characteristics Geology Grade, Value and Tonnage Estimates 2006 Advanced Program Drilling Bulk Sampling DMS Test Facility 2006 Exploration Summary

May 1, 2006

By Zhou Yanwen, Fudong Wang, Shing Liu

Mixed CrB2 and MoS2 powder (Cr:Mo=1:1 atomic %), without any further process, were used as the targets to be sputtered and deposited onto stainless steel and silicon substrates by pulsed DC power supply. The structures and properties of the CrBMoS films were then analyzed by using SEM, XRD, micro-hardness tester. The SEM morphology of the films showed dense, defect free structure, and the preferred orientations of the films were CrB2 (111) and MoS2 (200) according to XRD spectra. The thicknesses of the films were measured and the relationship between the deposition rates and pulsed factors was determined. The films, with the micro-hardness as high as 19GPa and friction coefficient as low as 0.02, could be considered to be the hard solid lubricant films.

Jan 1, 2015

By Bern Klein, A. Tugba Cebeci, Libin Tong

"Sensor based sorting faces two main challenges related to limited capacity/throughput and the ability of sensors to accurately discriminate based on estimated grades. This paper is aimed at improving sensor discrimination. Sensors have the ability to measure more than a single response. X-ray fluorescence (XRF) can detect and provide concentration information about a range of elements. Similarly, electromagnetic sensors (EMs) can generate magnetic susceptibility and conductivity responses over a range of frequency levels. The sensors thereby provide a response signature rather than a simply a single response that is a proxy for a metal grade. Furthermore, integrating sensor responses can improve the discrimination of metal bearing rock from waste. A study was conducted on a gold ore to assess sortability using XRF and EM sensors. A multi-variable regression approach was used to develop models that included a range of responses. Correlations improved significantly when compared to single response correlations. The approach showed that both positive and negative correlations contributed to the improved correlations. Stepwise regression simplified the models and showed that 2nd order interaction effects can be important. The approach also showed that combining different responses can improve discrimination accuracy. An important outcome of the study was that an ore that had been consider not to be sortable was determined to be sortable through the application of an approach that used the sensor responses in a more intelligent manner.INTRODUCTIONMining is aimed at recovering valuable minerals from their host rocks. Many methods are used to recover valuable minerals, and finding efficient and cost-effective ways is the key in research and production. . Ore sorting technology is fitting this definition. It not only discards waste rocks away from the concentrator but also recovers metal bearing ore particles that could be lost to the waste dump. The benefits of ore sorting include increased energy efficiency and reduced water and reagent usage in the downstream operations (Bamber, 2008; Gunson, Klein, Veiga, & Dunbar, 2012; Mazhary & Klein, 2015; Robben, Wotruba, Robben, von Ketelhodt, & Kowalzcyk, 2013)."

Jan 1, 2016

By H. Weissenbaeck, B. Nowak, M. Oesterreicher, R. Stastny

The producers of certain metals like nickel and cobalt increasingly face a shortage of easy-to-mine and easy-to-process ore bodies. Their focus is shifting towards alternative raw materials which in turn demand new, different extraction techniques. One potential route for processing a ferrous ore with a non-ferrous target metal is atmospheric leaching with hydrochloric acid followed by purification of the pregnant leach solution (PLS). For the separation of iron from the PLS, and, in turn, the extraction of the non-ferrous compounds, the following flow sheet is proposed. Pre-concentration of the PLS, oxidation of ferrous (if present) to ferric chloride, hydrolysis of ferric chloride leading to the precipitation of hematite and the evaporation of hydrochloric acid, followed by crystallization of non-hydrolysable metal chlorides by means of sparging hydrogen chloride into the solution. Hydrogen chloride required in the latter step is produced internally by super-azeotropic distillation of regenerated hydrochloric acid. The liquid filtrate from the crystallization step is recycled to hydrolysis. Depending on the specific composition of the PLS, the hematite produced contains only traces of other impurities, whereas the crystallized mix of non-hydrolysable metal chlorides – containing also the target metal in enriched form – contains ferric chloride only in an amount referring to the filter cake moisture. These crystals can then undergo further hydrometallurgical separation and extraction processes. As an example, this flow sheet is proposed for treating nickel laterite ores. Experiments related to the demonstration of crucial assumptions in the flow sheet are presented. Based on those experiments a mass and energy balance of the flow sheet was calculated and is presented here together with a table of the major consumables in order to provide a basis for an operating cost estimate and other process economics.

Jan 1, 2016

By A. B. Isaeva, A. Yu. Lein, A. A. Karpenko, V. V. Serova, A. P. Lisitzin, V. Yu. Rusakov, V. N. Lukashin

Abstract - The flux of sediment matter was determined using sediment traps near a black smoker ("Saracen’s Head," Broken Spur hydrothermal field) and the mineral and chemical compositions of the settled matter were examined. The metallic minerals are represented by Fe sulfides (pyrite and pyrrhotite), and Cu and Zn sulfides are also found in small and equal quantities. The hydrothermal suspended matter contains abiogenic calcite in amounts comparable to that in Ca sulfates. The content of silica and, specifically, of amorphous Si is unusually low. Such correlations between chemical elements and minerals, together with the isotopic compositions of S and C, are characteristic of a relatively young and active stage in the evolution of a hydrothermal system. Sediment traps within and under neutrally buoyant hydrothermal plumes collected biogenic material in addition to hydrothermal components. Microbial chemosynthetic production of organic carbon near the hydrothermal vent is comparable to primary production in the euphotic layer. Fe, Zn, Ca, Si, Ba and P are enriched in particulate matter in comparison to the background. A vast compound plume containing the discharge of multiple hydrothermal vents was found to the south of the Broken Spur hydrothermal field.

Jan 1, 1999

By Q. Ricoux, F. Goettmann, A. Maihatchi

"Electrodeposition processes are widely used in the metallurgical industry to produce, extract and refine metals from various feed materials. However, raw materials used to provide non-ferrous metals often contain high amounts of iron. In the presence of iron, while metals are plated at the cathode, electrowinning processes produce corrosive and highly oxidative ferric ions at the anode that are harmful for the process sustainability. In fact, these ferric ions cause dramatic current efficiency loss, induce high maintenance expenditures to limit the corrosion of devices and it results in the formation of impure and dendritic deposits on the cathode. Consequently, the management of iron in electrodeposition process became a major issue in non-ferrous metals production. Actually, numerous methods have been developed to limit the ferric ion concentration in the electrolyte or, at least, to limit its harmful effect. Many methods aim to limit the iron(III) concentration in the electrolyte, generally by coupling electrowinning to extraction process such as solvent extraction (SX) (Bender & Emmerich, 2015), ion exchange (IX) (Gula, Dreisinger, & Horwitz, 1996) or cementation (Kust, 1979) processes to remove ferric ions. Other routes consist of (i) using the ferric ions oxidant properties to leach raw materials, either directly in the electrolytic cell (Fanta & Tributsch, 1975) or through a secondary circuit (Cain, 1950), or (ii) reducing ferric ions through periodic reversal of direct current to enhance the formation of Fe2+ (Loutfy & Bharucha, 1980). On the other side of the spectrum, papers discuss methods to valorize the iron from by-products of the non-ferrous metal industry, that generates vast quantities of iron containing wastes (A. Agrawal, Sahu, & Pandey, 2004). Many studies on iron electroplating and electrolytic iron production from ores have been carried out (Cain, 1950; Mostad, Rolseth, & Thonstad, 2008), but very few have been conducted on waste or by-products. Therefore, we propose to build on the previous literature review to develop a process for the production of electrolytic iron from by-products.INTRODUCTIONNon-ferrous metals and their alloys are used in a large variety of applications. Aluminum and titanium are used for their strength, light weight and corrosion resistant properties in structural applications. Copper has been used in various applications requiring high thermal and electrical conductivity, as kitchen products and electrical wires. Nickel and zinc are commonly used as plating materials; nickel offers a wide range of working temperature and zinc is used for steel plating. Gold, silver, and platinum group metals are used in electrical/electronic applications, jewelry and chemistry as catalysts."

Jan 1, 2016

By Behzad Vaziri Hassas, Firat Karakas, Esra Tanisali, Mehmet S. Çelik, Ahmad Hassanzadeh

Coagulation is basically an aggregation process where particles settle under the influence of interfacial forces with electrostatic forces playing a governing role. Although particle morphology consisting of shape and roughness dictates the physical encounter of two particles, their eventual coagulation is not only influenced by columbic forces but also other interfacial forces such as hydrophobic interaction, which affects the extent of aggregation of particles through increasing the distance of interaction. Roughness is well known to increase the effective contact angle on hydrophobic surfaces and also enhance interfacial forces. In this study, the effect of morphology of particles and particularly roughness on the settling velocity and in turn coagulation tendency was investigated. Batch settling tests (BSTs) of different particle morphologies were investigated as a function of pH. Two different morphologies of silica particles were utilized with the same particle size distribution (PSD) including smooth-spherical and rough-spherical (Etched). Rough particles were prepared by acid etching technique using hydrofluoric (HF) at different time intervals (15-300 sec). Etched samples were identified and quantified by optic profilometry. Settling test results showed that the settling velocity of particles in a suspension of 2% solids in the massive settling region is significantly affected by particle morphology of the suspension. Coagulation results further revealed that aggregation of rough particles is faster than smooth-spherical particles. Coagulation results are elucidated on the basis of particle morphology and its effect on distance of separation through hydrophobic forces.

Jan 1, 2016

By R. M. de Carvalho

Empirical and phenomenological models of SAG and AG mills have dominated the scene for the last few decades, being used nearly every time a mill is scale-up or an attempt is made to improve its performance. However, in spite of their success, these models fail to describe the details of both the grinding environment and the breakage mechanisms. The result is a generally good track record, with a few – but very important – instances when these models fall short in their predictions, which can be very costly. Further, nearly all of these models require detailed calibration to industrial and pilot plant data, being costly in their application, although still with limited predictive capabilities. Recognizing these challenges, a new model framework has been proposed which overcomes the limitations of currently used models by coupling the microscale population balance model, the discrete element model and functions that describe internal classification at the mill grate. This model framework has already been applied to describe breakage in ball mills, with showing very promising results. However, in the case of SAG and AG mills a much greater level of complexity is involved in the model, given the interaction between the mechanical environment that is formed totally or, in part, by the ore itself, and the breakage response in the mill. The paper describes the model framework, demonstrating how it can address appropriately effects such as mill speed, mill filling and size distribution, on the response from the mill. Some of the advantages of the model are related to its intrinsic multi-component and dynamic nature, which allows simulating appropriately mixtures of ores of different competences in a transient manner.

Jan 1, 2012

By M. Lahtinen, B. Saxén, M. Latva-Kokko

The conventional jarosite precipitation process with neutralization by zinc calcine is widely utilized in the zinc industry. However, it has a significant drawback of causing losses of valuable metals like zinc, lead and silver to the jarosite. This comes mainly from the content of these metals in the calcine used for neutralization. As the zinc plants today want to maximize metal recoveries and minimize the amount of residues, this matter has become more and more relevant for zinc producers. Outotec developed and patented in early 2000 an improved version of the jarosite precipitation process in which the need for neutralization can be minimized, thus the metal losses to the jarosite also can be minimized. At the same time, the iron content of the jarosite increases and the amount of produced jarosite is smaller. The main feature of this process is to start the precipitation from ferrous iron after having reduced all the iron by zinc concentrate in a separate step before jarosite precipitation. Iron is then oxidised back to the ferric form simultaneously with jarosite precipitation. By this method, the formation of sulphuric acid is only half that compared to the conventional method and the need for calcine for neutralization can be avoided. High mixing and oxygen dispersion capability are needed in this jarosite precipitation process. Such capabilities are found in the Outotec OKTOP® reactor series. High performance reactors are not only needed to generate high quality precipitates, but also to maximize oxygen utilization; i.e., to minimize operation costs. Outotec’s latest development in this area is the OKTOP® plant product in which not only the reactors, but also all the accessories are designed, manufactured and delivered by Outotec. One responsible supplier ensures efficient and fast delivery and can provide mechanical and performance guarantees for the entire plant unit.

Jan 1, 2016

By Tatyana Alexandrova

The problem of processing refractory (rebellious) gold ores is important for all the countries involved in recovering precious metals from ores. Technological aspects of processing precious metal ores are examined in two respects: enhancing gold recovery from double refractory ores; and using carbonaceous ores on a production scale. The dispersed carbonaceous matter (DCM) present in concentrates causes the adsorption of [Au(CN)2]- complex on their surface during cyanidation process. Depending on the degree of graphitization and the organic carbon content in DCM (including kerogens and bitumen), the technology used to recover precious metals varies considerably. The problem of processing refractory (rebellious) gold ores is important for all the countries involved in recovering precious metals from ores. Depending on the degree of graphitization and the organic carbon content in DCM (including kerogens and bitumen), the technology used to recover precious metals varies considerably. The possibility of rare metals recovery, including rhenium, from black-shale rocks, has been examined. Comparative assessment of analytical methods of rare metals detecting has been carried out. It has been proved that neutron activation analysis is a promising technique. It has been shown that colloid-salt fraction (nanofraction) with particle size less than 1000 nm makes up to 3 wt% of black shale samples and is extracted by water under special conditions. The use of water instead of chemically active reagents provides insolubility of the mineral matrix and fully reflects the colloid-salt element of the samples. To sum up, the justification of the choice of technology for processing of carbon-bearing ores is based on examining the type of carbonaceous matter and its adsorption behavior. When the content of carbon of high degree of metamorphism is considerable, it is possible to recover platinum group elements and rare elements from this type of ores. The obtained results predetermine the general guidelines for creating new methods and techniques of processing carbonaceous material for integral development of solid minerals in the mining and oilfield areas of Russia.

Jan 1, 2016

By Rufus L. Chaney

A new technology is available to the Ni mining and remediation community to “phytomine” Ni from mineralized or contaminated soils using rare plants which hyperaccumulate Ni to over 1% of shoot dry matter. Research has identified useful plant species, and even bred improved cultivars of Alyssum murale and Alyssum corsicum for commercial phytomining in temperate regions. All agronomic practices (fertilization, soil amendments, planting and harvest methods) needed for economic phytomining were identified to attain high yields and high Ni concentration in the biomass. In tropical regions, other species are available such as Phyllanthus which accumulate over 1% Ni in dry shoots. These species are perennial so they regrow after annual cutting to harvest biomass. Expiration of our patents on the technology opens the opportunity for other organizations which control Ni rich natural soils or contaminated soils requiring remediation to commercialize the technologies. Inexpensive methods to remediate/revitalize Ni contaminated phytotoxic soils using agronomic approaches have also been developed and demonstrated at Port Colborne, Ontario, but adoption is delayed until formal agreements with government are completed. These new simple remediation and profitable phytomining technologies can obtain Ni from soils which contain Ni well below levels considered economic for current mining technologies, and the plants biopurify the Ni so it is easy to recover Ni metal from plant ash by pyrometallurgical or hydrometallurgical technologies. Although increasing pH decreases the solubility of Ni in all soils, raising pH increases Ni accumulation by Alyssum species. Hence usual chemical extraction methods for phytoavailable soil metals such as the DTPA- or NH4-OAc-extraction cannot predict Ni accumulation by Alyssum species.

Jan 1, 2016

By V. Prasad, A. Afacan, K. Popli, S. Dubljevic

Froth flotation is one of the most common and widely used separation processes in the mineral processing industry; however, its complexity means that complete understanding of the process has not yet been achieved. A dynamic fundamental model is needed to enhance the understanding of the process and to improve process control. It is challenging to capture all the phenomena involved; hence, we propose a multiscale modeling approach with a framework ranging from macroscopic (equipment scale) to microscopic (attachment, detachment) models along with distribution models for ore particle sizes. Real-time froth properties are obtained using a vision-based sensing system. These measurements can be used for developing a soft sensor for grade using statistical methods such as PCR (principal component regression) and PLS (partial least squares) regression. The fundamental model is updated in real-time using extended Kalman filtering. Attachment dynamics are studied for different particle size distributions. The modeling and soft sensing is tested on batch flotation cell for the pure mineral galena with different particle size distributions using Xanthate and MIBC as collector and frother, respectively. The model, online measurements and soft sensor are useful in developing monitoring methods for froth flotation.

Jan 1, 2015

By R. H. Coloquhoun

"INTRODUCTIONDome Mines Limited is located on 3,149 acres in Tisdale, Whitney and Shaw Townships in the City of Timmins in Northern Ontario. The mine and mill facilities are two miles from the town of South Porcupine, now part of greater Timmins.In April of 1909, J.S. Wilson of Massey, Ontario headed a party of prospectors into the Porcupine region. Disembarking from the Temiskaming and Northern Ontario Railway at mileage 222, they established an initial camp on the shore of Frederick House Lake. Following the lake ""break up"" they canoed to their destination, Porcupine Lake, and established a base camp on the west side of the lake by May 23, 1909. At a point approximately two miles from Porcupine Lake the moss on an outcrop was rolled back and gold was discovered.In the spring of 1911, the first mill structure was in the process of being built and consisted of 40 stamp mills, five S'x22' pebble mills and the ancillary equipment for a 300-400 T.P.O. operation. This structure was destroyed along with much of the Porcupine Camp by the famous Porcupine Fire of July 1911. By mid-1912, a steel ""fire proof"" structure was built and utilizing the salvaged mills from the fire, supplemented by the installation of three, 8'x30"" cylindro-conical Hardinge ball mills purchased third hand from Vipond Mines, processed 75,088 tons by year's end.The mill was again levelled by fire in October of 1929, this time caused by an overheated boiler stack. This 11 fire proof"" structure was immediately replaced by a wood structure and again the three Hardinge conical mills and the five 5'x22' pebble mills were restored and utilized. The new mill operated close to its daily capacity of 1500 tons during the last two months of 1930. During the rebuilding phase, the crushing plant was remodelled and a new crusher installed. These plants were protected from fire by a 60,000 gallon water tank and an automatic sprinkler system."

Jan 1, 1984

By S. Hussien, P. Somasundaran, P. Patra

"Rare earth elements (REEs) are essential for many applications in electronics, energy harvesting, and defense. The common resources for economic extraction of REEs are oxides such as bastnaesite and monazite, which are scarcely available in the earth’s crust. On the other hand, REEs are available in many clay and phosphate ores where REEs substitute Ca or Si in the mineral lattices or as physically adsorbed cations at negatively charged sites on the clay surface. While REE oxides readily dissolve in acid, making the chemical leaching of REEs an economically viable option, adopting a similar approach for leaching of silicates and phosphate ores is unfeasible because of significantly low REEs content in these ore deposits. Bio-leaching approaches are environmentally benign and economically viable. We investigated the bio-leaching (Acidothiobacillus ferrooxidans (Af) and the fungal Aspergillus niger (An)) of REEs from a phosphate ore, and examined the factors governing the leaching processes. Based on the shake flask leaching studies, an increase in surface area combined with an increase in pulp density (1-15 wt. %) was found to lead to an increase in the amount of REEs leached. In contrast, an increase in the surface area by reducing the particle size from 75 to 35 led to a decrease in the amount of REEs leached. These differing attributes are proposed to be due to the poor bacterial growth/activity with high F- ions in the leaching media, F- released from the edge-sites of the smaller particles. On the other hand, several advantages that associate with the Af bacterial bio-leaching processes relate to the media composition (Mg2+ and (NH4)+) and phenomena occurring at the electrical double layers of the mineral and bacterial- water interfaces. These studies suggested that leaching of particles occur in a layer-by-layer manner.INTRODUCTIONRare Earth Elements (REEs) are essential for many important applications, such as in electronics, energy generation, and defense. The common resources for economic extraction of REEs are typically carbonates such as bastnaesite and monazite, which are scarcely available in the earth’s crust (Y. Kanazawa and M. Kamitani, 2006). REEs are abundantly available in many clay and phosphate ores where REEs substitute Ca or Si of the mineral lattices. Conventional acid leaching of REEs from oxides is not economically feasible for clay and phosphate ores because of significantly low REE content (parts per billion) in these ores (Tian, J., Chi, R., Yin, J., 2010a; Moldoveanu G. A. and Papangelakis V. G., 2013; WK Goyne, LS Brantley and J Chorover, 2010). In some cases, REEs could be extracted from these ores via chemical leaching routes as they constitute reasonable amounts of REEs (0.1 - 1% REEs). A major challenge faced in general in chemical leaching processes (Chi, R., 1988) is the loss of REEs in the phosphate/gypsum precipitates/crystals, which are overcome in a step-by-step manner by sequentially removing impurities such as fluorine and calcium, including steps carried out at elevated temperatures. On the other hand, bio-leaching approaches provide environmentally benign and economical alternatives. Acidophilic bacteria are currently being used for industrial scale bio-leaching of Au/Cu/Ni from low grade ores. Studies on bioleaching of REEs from red mud (Al2O3) using Penicillium tricolor and Aspergilus niger (An), and, of bio-leaching (lab-scale) of phosphate rocks using Acidithiobacillus ferrooxidans (Af) have been reported (Boon, M., Heijnen, J.J., 1993; Qu, Y. and Lian, B., 2013). We conducted bacterial (Af) bio-leaching of REEs from a phosphate ore in shake flasks and columns, while examining the key factors that govern leaching kinetics."

Jan 1, 2016

"During the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests.In the current case, a composite sample of gold ore is dedicated to a Gravity Recoverable Gold (GRG) test. The properties of interest are the head grade of gold, the size distribution of the material, and the gold assay per size class. The sample is mixed and a sub-sample is taken to measure the feed properties: the size distribution and the gold assay per size class. The remaining material of the sample is subject to the first stage of concentration using the laboratory Knelson concentrator. The concentrate is analysed in its entirety, while a sample of tailings is taken for the same analysis. The remaining part of tailings is subject to grinding to feed the second and third stages of concentration. Similar sampling is performed at each stage.The concentration performances are analysed in light of these measurements. But what is the accuracy of the measurements of the properties? Pierre Gy’s theory of sampling, associated with a heterogeneity model built using the GRG test results, will answer this question. The current paper presents, through a real example, the calculation of the errors of the measurements of size distributions and gold assays performed during the GRG test. The uncertainties of the concentration performances and liberation size estimate are then calculated and their impact on the results interpretation is analysed.INTRODUCTIONDuring the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests. In order to take into account the ore variability in terms of gold deportment, it is recommended to perform variability studies (Dominy, Murphy, & Gray, 2011, Dominy, 2013) using samples representing various horizons or years of production. But for a given ore type, it can be necessary to perform many tests with different operating conditions (Brochot, 2012a). In that case, the variability of the samples is not due to the heterogeneity of distribution of the deposit, but only on the heterogeneity of constitution of the primary sample. The level of confidence associated with the estimated performance parameters is directly linked to the overall error (including sampling error) of the measurements performed during the tests."

Jan 1, 2016