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By Mohamed Ourriban, Stéphanie Somot, Éric Proulx, Jean-Sébastien Marois, Marjolaine Drouin, Paul Blatter, Ahmed Bouajila, Claude Gagnon

"The mining industry has to face increasing restrictions concerning the use of fresh water in Québec and throughout the world. Increasing recirculated water usage could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have a negative impact on mineral processing operations, thereby limiting the incentive for sustainable development initiatives. As a first step into selecting and testing remediation strategies, one of which being blending local waters, a mapping of process water quality (inorganic and organic fractions) allowed to locate zones in an industrial case study where fresh water is introduced into the circuit and to detect dissolution and precipitation zones. A complementary hydro-geochemical modeling study on water blends was also performed showing encouraging results towards the objectives of the project.INTRODUCTION The industry has to face increasing restrictions on the use of fresh water in Québec (Quebec Government, 2009) and throughout the world (Brown, 2003; UNESCO, 2006). The cost for the use of fresh water and for water management is highly variable and case-dependent (from 0.2 to up to 7 million dollars/year according to available private estimations, excluding the capital expenditure). It may be, or may become, significant for any plant; thus, risk assessment is of concern here. Using recirculated water could lead to a better control of the quality and the quantity of water supplied to the mineral processing units. Furthermore, it could reduce the volume of waste water to be managed and treated before its release to the environment. However, process water may have some positive and negative impacts on mineral processing operations (Janssen, 2003; Johnson, 2003; Rao and Finch, 1989). Negative impacts could limit the incentive for sustainable development initiatives. Water management strategies at mineral processing sites are supported both by a strategic plan and a water management plan. The strategic plan includes legal aspects, investment costs, potential benefits and various risk levels (Corder and Moran, 2006; Côte et al, 2006; Evans et al., 2006; MacIntosh and Merritt, 2003; McLellan et al., 2008; Merritt and MacIntosh, 2006; Robinson and Keddie, 2006; van Beers et al., 2007a; van Beers et al., 2007b; van Berkel, 2007). In practice, the strategic plan evaluates technical possibilities and costs of various scenarios, such as for example: bringing fresh water to the plant or recirculating waters, or using blends of both. Two important factors to consider in order to enhance the future production efficiency and to minimise risks are: the durability and the stability of the resource, both from quality and quantity points of view."

Jan 1, 2012

By Brad Wells, Wayne Bull, Wayne Dickinson

"Antiscalants were evaluated for control of calcium carbonate (CaCO3) in gold processing applications. Under severely supersaturated conditions, 100 percent inhibition was achieved with 30 ppm antiscalant. Laboratory and field testing established that an antiscalant could both inhibit scale buildup and remove an estimated 0.5 kg/m2 per annum of pre-existing scale. A program was developed to control CaCO3 at a gold mill experiencing severe scale buildup. Annual accumulation of as much as 3 cm of scale in process piping was reduced to unmeasureable levels when 10 ppm antiscalant was applied. No scale-related upsets in mill operation occurred during a five-month trial period.INTRODUCTION Inorganic mineral scale is a crystalline deposit that forms when dissolved mineral constituents exceed the solubility of the respective mineral phase. Formation of mineral scale adversely affects a wide range of industries and is of particular interest in mining and metals processing. Scale affects numerous stages of metal extraction processes. Restricted flow in piping, nozzles, valves, screens, pumps and other components used to transport mineral slurries, metal concentrates, and tailings as well as scale in millwater and thickener overflow circuits are primary concerns (Alfano & Boffardi, 1994). Heap leaching, comminuation, flotation, vat leaching, carbon adsorption, and heat exchangers as well as oxidation steps used in processing sulfidic ores are among key unit operations that may be adversely affected (Simmons & Gathje, 2003). Antiscalant chemicals are designed to prevent formation and growth of mineral scales such as CaCO3. These chemicals, which include two primary classes – phosphonates and anionic carboxylate polymers and copolymers - are added to the gold processing stream at low parts-per-million (ppm) concentrations to interfere with nucleation and growth of scale forming crystals and to disperse fine particulate material. Application points may be located throughout the gold extraction process. Evaluation of the performance of antiscalants plays a critical role in determining the best product for a specific application. Performance evaluations include laboratory testing, pilot scale studies, in-plant trials, and ongoing performance monitoring during mill operation."

Jan 1, 2014

By Hazel Lyman Nickel

Daring to try where others had failed, Herbert and Lou Henry Hoover translated from the Latin the principal (and first) textbook on the mining and metallurgical profession, De Re Metallica, 1556, which had been in use for two centuries and then had lain dormant for 350 years in a language unreadable except by a chosen few. Thus the Hoovers enriched the English tongue with a vitally important contribution to history in the fields of mining, metallurgy, and chemistry. To them it was a joint hobby, because they were actively interested in the beginnings of the mining profession in which they had both been trained. Illuminating the years of toil to perfect this translation shone their ideal of service to humanity, since, in the Preface, they refer to their task as "a labour of love", which had to find the moments for its execution in night hours, weekends, and holidays, extending over a period of about five years. And they add: "If the work serves to strengthen the traditions of one of the most important and least recognized of the world's professions, we shall be amply repaid". While a student at Stanford University, during the years of 1891-95, Herbert Hoover had become familiar with a copy of this Latin mineralogy classic, De Re Metallica, a rare book in the private library of Dr. John C. Branner, at that time head of the department of geology and mining. Another Stanford student in geology was also examining and studying the ponderous volume of twelve 'books'. She was Miss Lou Henry, of Monterey, who graduated in 1898, and the following year became Mrs. Herbert Hoover. Interwoven through the tapestry of their life experiences gleamed the silver thread of their interest in this mediaeval Latin textbook. Just nine years lacer, the Hoovers had commenced their translation, while they were in temporary residence in London after the seething years in China under the shadow of the Boxer rebellion.

Jan 1, 1949

By John Plecash

This paper comprises a general outline of all of the developments, including the history, geology, mining, milling, power and transportation installations, at the gold mining operation of La Luz Mines Limited and the copper mining operation of its wholly-owned subsidiary, Rosita Mines Limited, both located in north-central Nicaragua. The low-grade, gold-bearing ore-bodies of La Luz Mines, contained in highly fractured and folded Lower Cretaceous sedimentary rocks, were from 1909 to 1928, mined and treated by primitive methods by the La Luz and Los Angeles Mining Company. The abandoned property was acquired by La Luz Mines Limited in 1936, and was equipped with modern machinery and put into production in 1939. Between 1939 and 1948, the daily rate of production was in-creased from 300 tons per day to 2,-000 ton per day. The ore reserves available for open-pit mining were depleted in 1954. Since then, the entire production has come from under-ground operations.

Jan 1, 1963

By R. S. Bowman, G. S. Austin, J. M. Barker, P. S. Freeman

The physical, chemical and mineralogic characteristics of zeolites allow commercially important applications. While adoption of zeolite technology is slow in the United States compared to other regions of the world, continued testing and research has shown a wide range of uses for these minerals. They are important catalysts in petroleum refining, molecular sieves able to separate gases, and chemically inert carriers of reactants. The zeolite clinoptilolite produced by St. Cloud Mining Company (clino) (SC) is used in animal hygiene and animal feed, especially concentrated animal feeding operations (CAFOs), horticulture, water treatment, floor dry, aquariums, air and other filters, and odour control. Clino can remove cations from solution, and surface-modified zeolite (SMZ) is a sorbent for the removal of anions and neutral organics from water. Specific clino applications are: control of chemical pollution in groundwater, removal of organic compounds from oil field waters, and elimination of pathogens from sewage effluent. Combining the sorption capabilities of SMZ with chemical or biological transformations can yield complete removal of toxic materials from contaminated water. Continued development and marketing of zeolite products will be a growth market far into the future. The CAFO market for zeolites is the most significant growth area in the United States over the next few years. SMZ, currently less than 1% of St. Cloud sales, will continue to gain market penetration for many years.

Jan 1, 2004

By H. Powell

"This paper discusses how elemental analysis of conveyed bulk flows in real time using PGNAA (Prompt Gamma Neutron Activation Analysis) technology has resulted in significant improvements in advancing plant control in mineral processing operations. PGNAA through belt, full stream, continuous, multi-elemental, real time analysis technology is explained. Capabilities and limitations in plant operating environments are discussed including comparison with other real time, on-line technologies through review of published information available for on-conveyor minerals applications. Case studies include an iron ore and copper-gold company, both of which consider the technology an essential component in advanced plant control necessary in new process flow sheet designs, rather than an optimisation tool.INTRODUCTION Process operators rely on supply of a reasonable ore quality and consistency from the mine. Unfortunately neither the mining nor process operators have much control over the ore quality once it has been put into the crusher. Grade control typically stops once the material is designated as ore and the process plant operator needs to process it irrespective of quality. Plant control is most effective when technologies measure process streams directly and preferably in real time. Measuring sampling streams that are not representative of the primary flow will result in incorrect plant control decisions. Sampling coarse conveyed flows is expensive and impractical at many operations, however, this does not mean those flows cannot be measured. Investigations to find techniques suitable for real time elemental analysis have focussed on the application of known laboratory techniques to process streams. For conveyed applications, development of neutron irradiation techniques were most promising and early studies indicated potential success for bauxite measurement (Beurton et al, 1995). Tran & Evans (2001) concluded there was no equivalent technology to PGNAA in terms of material penetration power and that the technology was eminently suitable for basic industries such as cement. Nelson and Riddle (2003) evaluated PGNAA for possible use in the phosphate industry by using a unit installed in a cement plant to test performance on phosphate samples and ultimately recommended its use for further characterisation of the mine’s various ore types to improve stockpile allocation and grade control"

Jan 1, 2014

By J. E. Nesset, F. Rosenblum, J. A. Finch

"The self-heating of sulphides can be a major hazard in mining operations and concentrate handling, particularly during transportation and associated storage. Self-heating results from the oxidation of sulphide minerals and can vary from being insignificant to highly reactive and potentially hazardous to both humans and infrastructure. It is essential that there be a reliable test methodology that can measure and categorize a given sulphide material as to its self-heating potential. By their nature, sulphide ores and concentrates are complex and variable mineral mixtures making it difficult to predict their self-heating behaviour a-priori based on mineralogy or with a simple “snapshot” test. Furthermore, self-heating behaviour will depend on the state of oxidation of the sulphides as well as time, temperature and humidity. A review of available testing apparatuses and protocols that can be used to assess self-heating potential is presented. Each of these methodologies was examined in relation to its ability to measure and reliably predict the latent self-heating hazard of a sulphide material. Several of the methods were tested and compared to illustrate their strengths and weakness. The results indicated that a number of the test protocols may produce false negative indications of self-heating potential, constituting an obvious concern to the industry.INTRODUCTION Sulphides as well as other materials (coal, wood chips, hay, powdered milk, to name a few) that are stockpiled in an air atmosphere may undergo oxidation reactions which can result in the evolution of heat (Beever, 1984) (Hudak, 2002) (Blanchard, 2007). If the rate of heat generated exceeds the rate of heat dissipation, the stockpile temperature will rise, potentially leading to “hot spots” in the most reactive areas, and possibly even fires. The heat generation rate, the “self-heating” rate, depends on many factors such as the type and composition of material, particle size, moisture content, oxygen availability, ambient temperature and humidity, and of prime importance, the extend of prior oxidation, or more specifically, the presence of oxidation products. The desire of operators that mine, process or transport sulphide-bearing materials with a potential for self-heating is to have an accepted and reliable method for evaluating and quantifying the potential hazard of their material. The challenges are how to best measure the self-heating properties of given samples, and based on results, predict the behaviour of the bulk material over time and in-situ. Generally, when evaluating a given material one derives the self-heating characteristics of that sample at the time and under the conditions of testing, which will be referred to as a “snapshot test”. If that material is invariable, i.e. it will not change its response over time, then it may be considered to be a “predictive test”. However, if as a result of continuing oxidation or other changes, the material becomes more or less reactive with time, then a “snapshot test” is unreliable with respect to predictive ability."

Jan 1, 2014

By T. A. Grammatikopoulos, B. Vasily, A. H. Clark

"The St. Lawrence deposit is a large wollastonite skarn (ca. 9 Mt @ 41.3% wollastonite) adjoining the gabbroic-to-syenitic Leo Lake pluton in the granulite facies Frontenac Terrane of the Grenvillian Central Metasedimentary Belt. It occurs within a horseshoeshaped horizon of quartzite, open to the east. The skarn extends over 1.2 km2, and comprises wollastonite-dominant, wollastonite-clinopyroxene, and diverse quartz-feldspar-sulphide (-titanite) layers, interbanded with, and strongly folded within, the quartzite. As in the world-class wollastonite deposits of the Willsboro district, New York, no carbonate protolith is preserved, and calcite is a negligible constituent of the mineralized zones. Wollastonite development is nonetheless ascribed to metasomatism of a metacarbonate unit by magmatogene, silica-rich, CO2-poor (XCO2 < 0.05) fluids, at P = 350 MPa and ca. 560°C, or, alternatively, 550 MPa and ca. 630°C.Several high-grade zones, averaging >40% but locally exceeding 80%, of translucent, white, tabular wollastonite grains, with lengths of 0.2 cm to 5 cm, have been delimited by drilling. Preliminary beneficiation studies yield high aspect-ratio and high-purity (low Fe and Mn) concentrates.St. Lawrence compares favourably to other known prospects and operating wollastonite deposits: having good chemical and physical properties, low iron content, and high aspect ratios (>20:1). In addition, the deposit has a favourable size and location, and will benefit from a low Canadian dollar. Canada currently has no wollastonite production."

Jan 1, 2003

By Ken Wood

"A reliable source of water of an acceptable quality is vital to the success of any mineral processing plant using wet methods. For Cerro Verde, a new 108,000 t/d copper mill in southern Peru, the main source of raw water is the Chili River. The Chili River is heavily contaminated with raw sewage, industrial wastewater and agricultural runoff, and can also receive high sediment loads during the rainy season. The initial water treatment plant could not supply design flows of water due to the exceptionally poor water quality. Problems with treated water quality caused significant difficulties with water consuming equipment, such as the plant cooling systems. This paper details the Cerro Verde water system and changes from design through to start up from a mineral processing perspective.INTRODUCTIONMining, and mineral processing in particular, is a water intensive activity. Improving water system design and practice are key strategic requirements in moving toward a more sustainable mining industry. This case study forms a basis for ongoing research into water use and reuse at mines and mineral process plants, conducted by AJ Gunson, under the supervision of Dr. Bern Klein and Dr. Marcello Veiga at the University of British Columbia. The case study material was gathered through involvement with the design, startup, and redesign of the Cerro Verde water system.Cerro Verde is a low-grade copper porphyry mine, located near the city of Arequipa in southern Peru, at an elevation approaching 2,800 m. In 1972, one of the world’s first copper Solvent Extraction – Electrowinning (SX/EW) facilities was built on the site, processing oxide ore from two main open pits. In 2004, the operator, Sociedad Minera Cerro Verde S.A.A. (SMCV), approved a 108,000 t/d expansion project to process sulfide ore reserves through a new concentrator plant. The plant was designed under extremely tight schedule and capital constraints, with a mandate to intentionally avoid any overdesign."

Jan 1, 2008

By E. Wasmund

"Sandfire’s DeGrussa Copper-Gold operation in West Australia is a new high grade copper sulfide mine, which includes a 1.5 Mtpa concentrator which was completed in 2013.Early after commissioning, it was identified that the flotation capacity in the all-mechanical cleaner circuit was not sufficient. In order to improve recovery, the tail from the cleaner scavenger was sent back to feed the rougher scavengers. Test-work was done on-site to evaluate the possibility of using a flotation column as a pre-cleaner. A CavTube™ sparging system was selected, which is especially effective for fine ore particle flotation. Test-work was conducted at site using a 150 mm diameter unit, and then confirmed on a 500 mm diameter unit. A 4250 mm diameter full scale unit was installed in Q4 2014 and commissioned in Q1 2015. This unit gave some significant advantages including a reduction in re-grinding requirements, elimination of a circulating load and increase in the recovery of copper in the cleaner circuit and overall circuit.In this presentation, the benefits of columns and cavitation sparging for floating fine particles and rejecting fine entrained gangue will be explained. Also, the results from a lab unit and a pilot unit will be compared against the results of the full-scale unit. The paper will demonstrate the scalability of flotation columns, and which phenomena and scale-up criteria must be considered to be successful. Finally, some general observations will be made about the importance of columns in copper cleaning circuits.IntroductionSandfire Resources’ DeGrussa copper-gold concentrator is located approximately 900 km north-north-east of Perth in Western Australia. The project area landscape is scrubby mulga lands with few notable features. The climate is arid with high temperature and heavy summer downpours."

Jan 1, 2016

By Andy Fortin, Jeet Basi, Simon Hille

Goldcorp’s Eleonore mine is situated in Ell Lake area in the northeastern part of the Opinaca reservoir in the James Bay region of Quebec. The design of the 7000 t/d process plant includes crushing, grinding, bulk sulphide flotation, separate concentrate and tails leaching and detoxification circuits and residue handling. Detoxified flotation tails are thickened and filtered. A portion of the filtered tails are blended with the thickened detoxified sulphide concentration for paste backfill. The remaining filtered tails are trucked to the waste management facility. This presentation will describe the challenges faced with the commissioning and subsequent ramp-up of the flotation tails filter plant and the successes achieved by the multi-discipline team at Eleonore.

Jan 1, 2016

By Persio P. Rosario

Crushing has proven to be of fundamental importance in mine mill integration at Highland Valley Copper (HVC). Highland Valley Copper has achieved large throughput and good quality control through the gyratory crushers by proper blast design and better gap control. The next step, in optimizing the mine mill relationship, is evaluating the crusher liner wear and its shape influence on performance and product size reduction. To do this a laser measurement device has been developed and data is being recorded on the concave and mantle liner wear. This paper will outline the work to date and indicate specific objectives of the work.

May 1, 2002

By Norman O. Lotter, Dominic Fragomeni, Jorge Oliveira, Dee J. Bradshaw, Rebecca Monnapula

"The role of mixed collectors in enhancing the metallurgical performance of sulphide flotation processes was reviewed in 2008, and later published as an integrated theory by Lotter and Bradshaw, 2009. The theory proposed that xanthates, dithiophosphates and dithiocarbamates could be synergistically combined in an optimal formula to deliver improved grade and recovery. The approach uses a five-step structure, viz.1. A mineralogical study of the ore to be treated, identifying and quantifying the economic minerals (with hosting and association) and gangue species present.2. Selection of candidate collectors from this mineralogical information and from the known pulp conditions of that operation (e.g. Eh, pH).3. Design and execution of a factorial experiment to estimate and test the main effects and interactions, and to model the response surface for an optimum formulation [Box et al., 1978].4. Use of a High-Confidence Flotation Test platform in the factorial to reduce overall errors and allow for clearer observations [Lotter, 1995; Lotter and Fragomeni, 2010].5. Statistical design of a plant scale trial to measure and validate the gains [Napier-Munn, 1995; Lotter et al., 2009]. Eland Platinum, which was commissioned in November 2007, appointed a team to apply this theory to formulate an optimized mixed collector suite for use in the operation. The West Pit ore (UG2 - Normal ore) was sampled at site and brought to Xstrata Process Support, Sudbury, Canada, for mineralogical and metallurgical testing in 2008. Microprobe and QEMSCAN measurement characterized the type, grain size and textural association of the discrete Platinum Group Minerals (PGM) present. From the mineralogical data, it was clear that a mixture of dithiocarbamate and two xanthates would be a likely reagent suite selection. A factorially designed set of High-Confidence Flotation Tests studying these was performed, concluding that an optimal suite using certain amounts of these collectors was a viable formulation that would advance the grade and recovery performance at Eland above the standard PIBX by approximately 2.13% 4E PGE. The plant trial, which used a form of the replicated block design after Napier-Munn, 1995, and Lotter et al., 2009, exceeded this estimate with an overall PGE recovery gain of 2.48% (absolute basis) and a concentrate grade gain of 26.4 g/t PGE (absolute basis), as well as reducing chrome in concentrate from 2.04 to 1.62% (absolute basis). These gains proved to be statistically significant using the analysis of variance method, and have validated the theory."

Jan 1, 2011

By R. J. Schafer-Frentz, T. G. Joseph, M. Curley

"Greenhouse gas emissions—specifically of carbon dioxide—are a concern in Canada, where industrial sectors such as mining are stringently regulated for carbon release. Cumulative emissions are positively related to fuel consumption, which is controlled by several factors. This study investigates one of these factors: the product of vehicle speed and running surface total resistance (TR; sum of rolling resistance and grade resistance). Results show that TR directly affects fuel consumption and emissions—a relationship that is mathematically predictable. Fuel consumption and emissions, which are principally associated with the durability or deterioration of wearing course materials, were analyzed to aid selection of road construction capping material of low rolling resistance. In the oil sands region in the province of Alberta, ground conditions change seasonally. Therefore, the annual fuel consumption for the same wearing course material was also compared. Results demonstrated that haul truck size was a contributing factor, but vehicle speed and TR more strongly influenced fuel consumption and emissions. ¦ KEYWORDS Carbon dioxide, Emissions, Fuel consumption, Grade resistance (GR), Greenhouse gas (GHG), Haul truck, Rolling resistance (RR), Total resistance (TR) RÉSUMÉ Les émissions de gaz à effet de serre (GES), et particulièrement celles de dioxyde de carbone, sont un problème au Canada, où les secteurs industriels tels que l’exploitation minière sont rigoureusement réglementés pour leurs émissions de carbone. Les émissions cumulées sont indéniablement en lien avec la consommation de carburant, qui est contrôlée par plusieurs facteurs. Cette étude examine l’un de ces facteurs, à savoir le produit de la vitesse du véhicule et de la résistance totale de la surface de roulement (la résistance totale, ou RT, est la somme de la résistance au roulement et de la résistance due aux rampes). Les résultats montrent que la RT affecte directement la consommation de carburant et les émissions, un lien qui est mathématiquement prévisible. La consommation de carburant et les émissions, qui sont principalement associées à la durabilité ou la détérioration des matériaux composant la couche d’usure, ont été analysées afin de contribuer à la sélection de matériau de recouvrement pour la construction de routes ayant une faible résistance au roulement. Dans la région des sables bitumineux de l’Alberta, les conditions au niveau du sol changent à chaque saison. Ainsi, la consommation annuelle de carburant pour le même matériau composant la couche d’usure a aussi été comparée. Les résultats ont montré que, si la taille des camions de transport est un facteur déterminant, la vitesse des véhicules et la RT influencent davantage la consommation de carburant et les émissions. ¦ MOTS CLÉS camion de transport, consommation de carburant, dioxyde de carbone, émissions, gaz à effet de serre (GES), résistance au roulement, résistance due aux rampes, résistante totale (RT)INTRODUCTION In Canada and around the world, global climate change has become a topic of great concern and discussion. Pres-sure on world leaders to quickly reduce their carbon footprint is prevalent, prompting new standards and regulations in various industries, including mining and oil and gas. In 2017, the Government of Alberta implemented a carbon tax. The majority of mining activities in this province are truck-shovel operations, where a large fleet of ultra-class trucks is loaded by shovels. Ultra-class haul trucks, classified as those with a capacity of 218–363 tonnes (t), emit high levels of carbon as they travel to processing entry points and waste dumps as designated by the mine plan and mine dispatcher. Mined ore and waste is typically moved over two 12-hour shifts per day throughout the year."

Jan 1, 2019

By Steve Wilson, Bern Klein, Jeff Drozdiak, Stefan Nadolski, Andrew Bamber

"In the adaptation of high pressure grinding rolls (HPGRs) to hard-rock mining applications, circuit development has mainly focused on placing HPGRs in the role of tertiary crusher in the preparation of ball mill feed. In order to take advantage of the potential energy benefits associated with HPGR and stirred mill grinding technologies, work was done to investigate the potential of and resultant energy benefits of placing the HPGR in series with a high speed stirred mill in replacement of the conventional cone crusher / ball mill arrangement. The proposed circuit was designed to operate with two stages of HPGR grinding followed by high speed stirred milling.Using a pilot-scale HPGR unit inline with a 20 liter stirred mill, the design criteria, circuit arrangement and consequent comminution energy requirements for a circuit processing copper sulphide ore from Teck Resources’s Mesaba Copper project were determined. These results were then compared to two other circuits, an HPGR / ball mill circuit and a conventional crusher / ball mill circuit processing the same ore.The testwork indicated at a proof-of-concept level that the HPGR / stirred mill circuit could potentially be appropriate for this duty and further work on the concept is merited. While the results indicate that the HPGR component of the circuit was more energy efficient than conventional cone crushing, the energy efficiency of the stirred mill was found to be lower than that of a comparable ball mill undertaking the same duty. However, increased energy efficiency of the stirred mill portion of the circuit is possible with further optimization and further work on the concept is indicated."

Jan 1, 2010

By V. J. Southey

"This paper reviews the history of Wabana Mines from 1892 to 1966, inclusive, in order to clarify the essential factors involved in the achievement of maximum mining efficiency and in the search for an acceptable product to satisfy changing market requirements. It outlines the progressive steps taken to mechanize both surface and underground operations, and forecasts anticipated performance, assuming certain major plans could have been implemented. Results of extensive research in the treatment of the complex ore are discussed. Selected processing alternatives are compared as to feasibility in a summary incorporating estimated capital and operating costs."

Jan 1, 1969

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By Chris Fleming, John R. Goode, James Brown

"Data will be produced from two uranium feasibility studies that were conducted in 2008, both involving uranium recovery from leached slurry by resin-in-pulp (RIP) with strong base resins. Excellent metallurgical results were produced in RIP pilot plants in both studies, and the loaded resins were eluted with strong sulphuric acid and recycled to RIP in an integrated process. Resin losses by either abrasion or mechanical breakage were immeasurably low.Metallurgical results from these two campaigns will be presented, along with an economic analysis of RIP versus the alternative process of CCD or filtration and solvent extraction.INTRODUCTIONThe recovery of uranium directly from pulp with strong base resins in RIP contactors was practiced commercially in the USA in the 1960s, but the process never established itself as a viable alternative to solid/liquid separation and solvent extraction. This was due mainly to the necessity to do a sand-slime separation partially resulting from the unavailability of coarse resin beads, inadequacies in the design of the RIP contactors and screens to separate resin from pulp, as well as problems with the strength and durability of resins in agitated pulps.There have been significant advances in the last 30 years in each of these areas. All the commercial resin manufacturers are now producing very tough, durable, strong base resins, and are manufacturing them in a large bead size that is better suited to RIP applications. In addition, with the emergence and wide spread implementation of the carbon in pulp process in the gold industry in the 1980s, many innovative techniques for preparing leached slurries and separating carbon from pulp have become firmly established. These techniques have proven to be equally applicable to resin separation from pulps in RIP contactors."

Jan 1, 2010

I N the introductory chapter to "Man and Metals," T. A. Rickard wrote "Five hundred thousand years ago the first footfalls of man&apos;s oncoming echoed down the corridors of time." This phrase has always appealed to me, not only for its resonance but because it seems to place in some perspective man&apos;s place in the cosmos. As we go about our daily occupations and as we meet here tonight, we must agree that we have come a long way slowly at first through the ages of change but with a quickening pace that has brought to man&apos;s know-ledge and use, within the last hundred years, more ideas, more material advantages, more opportunities and more comforts than were ever imagined or dreamed of in those long corridors of time. Looking back to the dawn of his-tory, a mere five thousand years ago, there is one aspect of the birth and growth of civilization that has particular significance for the miner and the metallurgist.

Jan 1, 1965

By M. Arvola, A. Mäkinen, N. Isomäki

Arsenic is a compound that has no significant market value. However, it needs to be removed from ores, concentrates and other process streams because of environmental or technical processing concerns. A wide range of arsenic containing minerals exists in nature, and in many instances these minerals are also associated with the ones that have commercial value. For example, sulfide copper ores are normally closely associated with minerals like enargite, Cu3AsS4 and tennantite Cu12As4S13. After mineral processing these arsenic sources can report to the waste waters and these effluents need to be treated before discharge or recycling. Ferric arsenate precipitation is a well-established method for stabilizing arsenic in effluents. Electrochemical arsenic removal utilizes the same adsorption/precipitation ideology as ferric arsenate precipitation. Electrochemical arsenic removal, even though it is a simple process in terms of equipment, is a complex system involving chemical and physical mechanisms taking place simultaneously to remove dissolved and/or solid arsenic components from wastewaters. The whole process can be described by the following three steps: 1) electrolytic oxidation at a sacrificial anode (dissolving electrode metal, iron for example), 2) chemical reaction between dissolved iron and arsenic to form a solid precipitate and 3) aggregation of the particles to form flocs, which can be removed by known solid/liquid separation methods. Electrochemical arsenic removal is a very efficient way to remove arsenic from different waters to very low residual concentrations.

Jan 1, 2016