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By R. Blosser

Phelps Dodge introduced a process improvement model known as Quest for Zero in 2001. In 2004, the focus of Quest for Zero shifted from corporate-led initiatives to projects led by site personnel. The Hydrometallurgical Division at Morenci focused on two (2) significant process improvements: reducing electrolyte bleed and organic losses. In September 2004, Morenci kicked off a bleed reduction project to reduce electrolyte bleed by 45%. By the end 2005, electrolyte bleed was reduced by 55% through understanding and reduction of variance. Significant process changes made during this time period include changes in acid-addition strategy, reduction of uncontrolled bleed, and optimization of bleed placement. In April 2005, the organic reduction project began with the goal of reducing losses by 15%. Operational improvements during this project included improved organic recovery systems, mixer speed optimization, and picket fence installation. By the end 2005, this project reduced organic losses by 35% and current losses are 48% lower than at the start of the project. These projects and smaller Questfor Zero projects have resulted in sustainable annualized savings of $13 million in Morenci hydrometallurgical operations. Through the use of Six Sigma tools, process variances can be controlled and reduced.

Jan 1, 2007

By C. Horstmann, D. Andreo, G. Barthold

"The concept of large single line grinding circuits provides a valid answer in project feasibility studies by reducing capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational aspects, in terms of higher and greater process stability, and reduced operational costs mainly due to the associated lower maintenance expenditures. However, concerns exist in the minerals industry on whether large single line grinding could reduce the overall concentrator plant availability. The mechanical design and integrity, the mill and gearless mill drive integration, as well as assets management aspects of this type of equipment are the key to guarantee successful availability records. Together with an overview of the added value provided by large single line grinding circuits, this paper focuses on risk mitigation strategies during mill and gearless mill drive integration, as well as on the design of the equipment itself, for the key aspects which could put at risk the operations availability.INTRODUCTIONDespite a large long term demand for commodities, the mining industry has never faced complex challenges as it is doing today. Decreasing high-quality and accessible deposits, declining ore grades in existing mines, shortages of electrical energy (e.g. in Chile) and an aging workforce are the most significant among the megatrends affecting our industry. In addition to this, flat underlying commodity prices and high price volatility are currently posing strong requirements to miners when entering into the process of approving investments.Nowadays to get projects financially approved (optimizations, expansions, new plants), capital expenditure has to be reduced, as observed up to 30% compared to the last decade, and at the same time the plant design has to be such to demonstrate that operating costs will also be significantly lower than in the past.When it comes to the concentrator plant, the concept of large single line grinding circuits provides a valid answer in project feasibility studies by significantly reducing the capital investment requirements compared to parallel lines for the same plant throughput rates. The benefits of this concept are reflected as well on the operational costs, in terms of higher and greater process stability and reduced maintenance expenditures."

Jan 1, 2016

By Marc Arpin

La Bolivie possède tout pour réussir. Son vaste territoire de plus d'un million de km2 et qui occupe une position stratégique au coeur du continent sud-américain recèle des ressources naturelles (forêts, minéraux, gaz naturel, etc) variées et abondantes. Elle a une frontière avec pas moins de 5 pays dont le géant que constitue le Brésil ainsi qu'avec l'Argentine, l'autre puissance régionale. Pourtant, malgré tous ces atouts, la Bolivie demeure l'un des pays les plus pauvres du continent. Ce paradoxe n'est nulle part mieux reflété que dans le secteur minier. Celui-ci fait face à une situation de crise en dépit d'une tradition minière de plus de quatre siècles et d'un potentiel géologique indiscutable ayant conduit à la découverte et à l'exploitation de fabuleux gisements d'argent et d'étain. Les habitants des districts miniers vivent dans des conditions de pauvreté extrême et les indicateurs de développement humain de ces régions sont parmi les plus bas en Amérique du Sud. La Bolivie réussit difficilement à attirer les compagnies minières alors que, chez les voisins, et particulièrement en Argentine, qui n'a pas de tradition minière, les investissements miniers majeurs affluent. Dans cette conférence, nous chercherons à expliquer les causes de cette situation et proposerons des solutions possibles.

May 1, 2001

By R. Agius, A. Nacu

"Cyanide destruction technologies are implemented at gold and silver operations to comply with the International Cyanide Management Code and meet ever more stringent discharge limits. Currently, the most common chemical cyanide destruction processes used in industry are sulfur dioxide/oxygen, hydrogen peroxide, and Caro’s acid. The cyanide destruction process used at an operation must reliably generate streams of acceptable quality at all times, and depends on numerous factors, including permit discharge requirements, tailings chemistry, location, site-specific climatic conditions and size of the operation. Selecting the most appropriate cyanide destruction process and determining the process design criteria requires accurate laboratory testing. This paper presents and discusses the results of a number of cyanide destruction evaluations that have been conducted to reduce cyanide concentration in process solutions or cyanidation tails. Laboratory testing provides important insights into reagent consumption and other factors required to achieve the target residual weak acid dissociable cyanide (CNWAD) levels.INTRODUCTION Process solutions associated with the extraction of gold and silver contain several forms of cyanide. The most toxic form of cyanide is free cyanide, which can be present as a dissociated cyanide anion (CN-) or gaseous or aqueous HCN. Weak or moderately stable cyanide complexes such as those of zinc, copper and nickel are classified as weak acid dissociable (CNWAD). Although less toxic than free cyanide, weak acid dissociable cyanide complexes are considered “ecologically sensitive” forms of cyanide and are regulated in most jurisdictions. In practice, reported WAD cyanide values comprises both free cyanide and weak acid dissociable cyanide complexes. Cyanide complexes with gold, mercury, cobalt and iron are referred to as strong acid dissociable complexes (CNSAD) and are much more stable, even under mildly acidic conditions. Another term commonly used in cyanide chemistry is total cyanide, which represents all cyanide compounds present in solution. Total cyanide levels in solutions are always equal to or higher than WAD cyanide values and the difference between the two usually indicates the presence of iron-cyanide compounds. Typically in Canada, CNTOTAL levels cannot exceed 1 mg/L in solutions discharged to the environment."

Jan 1, 2017

By C. Edwards

ABSTRACT The versatility and specificity of rare earth elements (REEs) have led to their use in an everincreasing variety of applications in new technologies; consequently, demand for REEs has increased significantly. However, separating REEs safely and effectively is a complex and expensive process. This paper presents a review of REE mineral processing technologies, providing an update on current capabilities in REE mineral processing and REE extraction from the major commercially valuable REEbearing minerals such as bastnaesite, monazite, and xenotime, as well as the ion-absorption type of REE deposits.

Jan 1, 2013

By W. A. Gow, J. A. Vezina

"A new process for treating scheelite for the production of tungstic tri-oxide is described. The novelty of the process resides in that an ion-ex-changer is used to convert sodium tungstate to either ammonium tung-state or tungstic acid.The process consists of a conventional hydrochloric acid leach of the scheelite concentrate, and the dissolution of the impure tungstic acid thus produced with sodium hydroxide at pH 8. The sodium tungstate solution is clarified and passed through a column of Dowex 50Wx8 ion-ex-change resin to exchange the sodium ions for either hydrogen or ammonium ions, both being suitable. The tungsten-bearing column effluent is evaporated to crystallize the tungsten as ammonium tungstate; the crystals are washed with nitric acid and water and decomposed by heat to pro-duce tungstic trioxide of high purity.Ninety-six per cent of the tungsten in the concentrate may be re-covered as tungs tic trioxide (W03), and the reagents consumed are 0.7 g HCl, 0.41 g NaOH and either 1.73 g NH.Cl or 225 g HCl per gram of tungsten."

Jan 1, 1966

By P. T. O'Kane

The PLATSOL® process, initially developed for the treatment of the NorthMet Cu/Ni/PGM concentrate, has seen over the recent years its applicability extended to include numerous other Cu/Ni concentrates of the same type, as well as other precious metals-containing feedstocks. However, several concentrates were found refractory to the typical PLATSOL® conditions, more particularly so the platinum. Attempts to extend those conditions, such as higher temperatures (250°C), longer retention time, increased oxidation conditions, higher chloride additions, were not successful. Detailed mineralogical investigation of those PLATSOL® leach residues indicated the main refractory mineral to be cooperite (PtS). Further metallurgical investigations showed that a thermal pre-treatment of the concentrate effectively unlocked the refractory platinum minerals for the subsequent leach. Temperatures between 400 and 750°C were tested, with the optimum being found around 650°C. The kinetics of the pre-treatment process were fast, and one hour at temperature proved sufficient. Under those conditions, PLATSOL® extractions were re-established around 95% for both platinum and palladium. From a mineralogical examination of the calcine, it was shown that the effect of the pre-treatment was to transform the cooperite and other refractory sulphides into metallic platinum and alloys, amenable to the PLATSOL®. The implications of the pre¬treatment step for the processing of PGM concentrates arc briefly discussed.

Jan 1, 2004

By Marc Symbaluk

Core Programs Current ? Aboriginal Involvement Program ? Adaptive Forest Management / Forest History Program ? Grizzly Bear Research Program ? Natural Disturbance Program ? Foothills Growth and Yield Association ? Foothills Stream Crossing Program ? Fish and Watershed Program ? Caribou Landscape Management Association ? Social Science Program ? Local Level Indicators Program ? Communications and Extension Program ? Geographic Information Systems Program ? Mountain Pine Beetle Ecology Program In Development ? Climate Change Program ? Forest Community Program ? Water, Quantity and Quality Program (Water for Life) ? Circumboreal Initiative ? Yellowhead Ecosystem Management Group

May 1, 2008

By H. P. Pew

THE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by T HE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by 85 miles wide, is the largest in Canada in areal extent, in the amount of oil in place and in the current producing rate. The discovery well was completed in the middle of 1953. The field has grown until its present area is 369,820 acres. There are 74 working interest owners in the field. Early in the producing history of the Pembina field a committee of operators was formed on a permanent basis. The Pembina Operators' Committee has established a permanent staff, which compiles and distributes pertinent field information on a regular basis to all participants. The Alberta Oil and Gas Conservation Board has dealt with field-wide problems primarily through this committee. Expansion of the field was rapid as shown by the number of wells completed -from 135

Jan 1, 1961

By Fei Dai

Musculoskeletal disorders (MSDs) are a group of painful disorders that affect muscles, tendons, nerves, joints, cartilage, and ligaments. They are a serious problem among the workforce in the United States. In the construction industry, high physically demanding tasks expose construction workers to a number of well recognized MSDs risk factors such as repetitive motion, high force exertion, and awkward body posture. Finding ways to effectively identify and evaluate risks of MSDs can significantly alleviate this problem. To this end, this paper reviews state of practice and research in the assessment of risks of MSDs among construction workers, in which a number of biomechanical models have been developed to evaluate joint and tissue loading with the aid of state-of-the-art remote sensing technologies. Findings from the review reveal that despite the advances in tracking human motion and muscle activities, current remote sensing approaches still involve sophisticated instrumentation and expensive experiment setup. These factors greatly limited the applicability of such approaches in real construction settings. How can we detect and evaluate the construction worker?s MSDs risk in real work environments? In this paper, strategies by utilizing video surveillance systems are presented, to set the stage for addressing the above question and discussing future research in real-time, marker-less, and costeffective MSDs risk assessment.

Aug 1, 2013

By A. Sokolov, E. Hasikova, V. Gostilo, V. Titov

Introducing online X-ray fluorescence (XRF) analyzers in the mining and processing industries can lower costs and improve the representativeness and speed of analysis. The applicability of the CON-XTM industrial conveyor XRF analyzer for continuous measurement of potassium content in process materials was demonstrated at various stages of potassium muriate (MOP) production. The CON-X analyzer produced reliable and accurate results for sylvinite ore (27–36% KCl), MOP cake after flotation (88–97% KCl), and NaCl residue (1.5–5% KCl). Tests of the analyzer at an MOP-producing plant showed a < 0.5% difference between online and laboratory results.

Jan 1, 2014

By Jack Young

U. S. Steel Canada Inc.’s Lake Erie Works is the last green field integrated plant to be built in North America. The plant was designed using the best available environmental technology to develop an environmentally friendly production facility. A summary of the technology and measures used in the construction of the plant are summarized in this paper.

Jan 1, 2015

By C. H. Attwood

Introduction In presenting this paper on the water-power resources of the Province of Manitoba, it was considered that a brief resume of the power resources of Canada, of the power already developed, and its utilization in the industries 9f the country, would be of particular interest in showing the rapid progress that has already been made. Amongst Canada&apos;s national assets, water power occupies a foremost place because of the facilities it provides for the development of her other great natural resources. The rapid development of the mining, pulp and paper, and general manufacturing industries, and the concomitant growth in urbanization, with its numerous demands for domestic, commercial, and municipal service power, have combined to stimulate hydraulic development to a point surpassing even the most sanguine predictions of a few years ago. With the bringing into operation during 1928 of hydraulic turbines aggregating over 550,300 h.p., and of a further 378,400 h.p. in 1929, Canada&apos;s total hydraulic development at the end of 1929 amounted to over 5,700,000 h.p., and in this year, 1930, the active construction in hydro-electric plants throughout the country totals in excess of 1,600,000 h .p.

Jan 1, 1930

By Paul W. Shelley, Daniel J. Hodges

The mining industry is undergoing a period of rapid transformative change.&nbsp; This is the result of the social and financial accountabilities that the industry is faced with because of the world&rsquo;s desire to cap average temperature increase to 1.50C above pre-industrial levels (UNFCC, 2016).&nbsp; To limit global warming to 1.50C, greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030.&nbsp; In hard rock mining, comminution is identified as the major energy consumer, being responsible for 40-60% of the electricity use.&nbsp; It follows that comminution is the major greenhouse gas emission process of the mine.&nbsp; All effort is being made to radically reduce the carbon emissions of comminution. Grinding media plays a large role in the energy consumption and carbon emission story.&nbsp; In recent years industry practitioners have attempted to quantify the grinding media carbon footprint.&nbsp; This paper makes a definitive contribution to that discussion.&nbsp; The grinding media carbon footprint is quantified in Scope 1, 2 and 3 emission terms in the context of a grinding media supplier.&nbsp; Major emission contributors, steel, natural gas and electricity are discussed in detail.&nbsp; The steel industry transition is a key factor. The paper will explore the steel industry transition and its effect on grinding media manufacturing.&nbsp; The carbon footprint of heritage steel process routes are analysed and compared with the process routes of the future.&nbsp; Emerging steel making technologies are presented and discussed.&nbsp; The future of the steel manufacturing and procurement route for grinding media is proposed. This narrative allows for a comparison between the heritage carbon footprint and the future carbon footprint of manufactured grinding media.&nbsp; Of equal importance is the opportunity of reducing the grinding media carbon footprint in the field.&nbsp; The paper explores possibilities of reducing the grinding media carbon footprint at the customer site.&nbsp; Media in use options are presented that take account of the mineral characteristics, the mill dynamics, and the product metallurgy to optimise both carbon footprint and media performance. It is intended that this is a landmark paper in the discussion of the carbon footprint of grinding media.

May 4, 2025

By S. Litke

Elemental sulfur was stockpiled at the Mount Polley Mine for use as a source of sulfuric acid as part of research into leaching copper from oxide ores, but the project did not proceed beyond an initial pilot- scale evaluation. Since placement, the sulfur has oxidized and some sulfuric acid leached into the underlying rock. The reaction of the acid with these underlying materials has been studied as part of an evaluation of the effects of leachate from the pile. The rock underneath the sulfur pile is composed dominantly of primary and secondary alumino-silicates with less than 1% carbonate (calcite) and iron sulfide (pyrite). In its unaltered condition, the rock is classified as non-acid generating. Conceptually, it was expected the sulfuric acid would be neutralized by the rock to varying degrees resulting in a series of pH-controlled weathering fronts progressing from leached near the contact with the sulfur pile (pH <3), to active neutralization by silicates (pH 4–5), to active neutralization by carbonates (pH >7). The rocks underneath the pile were sampled to determine the extent to which the rocks had reacted and their long-term stability after removal of the acid source. INTRODUCTION When rock is blasted and excavated to facilitate mining ore, it is typically placed and stored on the surface in piles. The resulting drainage may have a neutral to basic pH (i.e., non-acidic drainage) or a low pH (i.e., acid rock drainage, ARD) depending on the mineralogy of the rock being stored in the piles. Acid- base accounting (ABA) can be used to characterise the two types of rock: potentially acidic drainage generating (PAG) and not potentially acidic drainage generating (NAG) (Price, 2009). According to Price (2009), NAG is defined as having an excess of neutralization potential (NP) in the rock in the form of calcium carbonate-like minerals when compared to acid potential (AP), i.e., a Neutralization Potential Ratio (NP/AP = NPR) greater than 2.0, whereas PAG is classified as having an excess of AP (i.e., an NPR less than 1.0). This is a conservative estimate and may be slightly modified depending on the mineralogy at specific mine sites. Rock with an NPR of 1–2 is also capable of generating acid (Price, 2009) and, depending on the mineralogy, may also be classified as PAG. Drainage from PAG material can generate acid immediately, or many years after it has been exposed to surface conditions. Disposal techniques depend on the category (i.e., NAG or PAG) and reactivity of the rock stored in the piles.

Jan 1, 2019

By A. M. A. Mohamed, F. H. Samuel, S. Valtierra, H. W. Doty, A. M. Samuel

"The influence of Fe, Mn, Cu and Mg alloying additions, Sr modification and grain refinement on the microstructure of as-cast and solution heat-treated Al-10.8% Si alloys was investigated using optical microscopy and EPMA techniques. The results showed that the modification effect of Sr diminished with increasing Cu and Mg additions, due to Sr-Cu-Mg interactions. Strontium caused segregation of AlzCu in areas away from eutectic Si regions, and altered the precipitation sequence of the a-Ah5(Fe,Mn)3Siz iron intermetallic from post-dendritic to pre-dendritic, with the phase observed within the a-Al dendrites. Depending upon the alloy Fe and Mn content, a coarser variation (""sludge"") of the a-Fe phase occurred, in the form of polyhedral shaped particles. The AhCu phase dissolved almost completely during solution heat treatment, while Al5Cu2Mg8Si6, sludge, and a-Aln(Fe,Mn)3Siz phases persisted in all alloys, particularly at high Mg and Fe levels. The f3-Al5(Fe,Mn)Si phase dissolved partially in Sr-modified alloys, the dissolution becoming more pronounced after solution heat treatment."

Jan 1, 2006

By C. Samuelsson, H. Ahmed, B Björkman, A. Andersson

The cost of raw material and energy is a continuing driving force towards working with increasing the recycling of ore based steelmaking residues. In Sweden no on-site sinter plants are operated at the integrated steelworks. Instead, selected residues from the plant are incorporated in a cold bonded briquette product which is recycled to the process via the blast furnace (BF). Since the BF sludge is the major bleed of zinc out of the furnace it is required to be de-zinced prior to recycling in the briquette product. In the present work landfilled BF sludge has been characterized with respect to chemical composition, particle size distribution, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The sludge was also subjected to laboratory scale hydrocyclone trials aiming at reducing the zinc content making the sludge viable for recycling. The results suggested that the sludge had been agglomerated prior to the characterization and hydrocyclone treatment. The zinc removal using the hydrocyclone was discussed.

Jan 1, 2015

By K. Purazrang, P. Musavi Garavi, P. Sh. Naseri, P. Abachi

The fracture behavior of high strength Al7050 alloy was investigated at room and elevated temperatures using small size, V-notched tear (called Kahn specimen) and compact tension, CT, specimens, respectively.To study the elastic-plastic behavior of the alloy, the tensile test was also performed on the sub-sized cylindrical tension test specimen. The microstructure of the alloy was examined using optical- and scanning electron- microscopy. The rupture mechanisms and crack path were also studied by examination of specimens&apos; fracture surfaces using SEM. The microstructure examination revealed equiaxed grains and some elongated grains in rolling direction, with the areas of partial re-crystallized grains where coarse intermetallic particles are mostly found.In general, fracture surfaces were indicative of dimpled ductile type. Considering the fractographs of tensile specimens, the void growth mechanism is also dominant in fracture of these specimens. Nevertheless, in some regions, smooth areas can be observed due to the friction during rupture process. The results of mechanical tests at RT made the evaluation of tear strength to 0.2 % tensile yield strength ratio, as a measure of notch toughness, available. According to elevated temperature, 150°C, test results and plots of log da/dt vs. log KI , the crack propagation behavior over discrete ranges of crack growth rates could be assumed linear and then be obeyed as a power law equation in the form of da/dt = A (KI)n .

Jan 1, 2015

By F. Baczek, S. S. Rocks, D. Chaiko, T. Walters

The atmospheric leaching of chalcopyrite concentrates using acidic ferric sulfate lixiviants is well known to suffer from slow leach kinetics and poor copper recoveries. A number of approaches have been proposed for improving both leach kinetics and recoveries in this system. Many of these, while effective, suffer from high CAPEX and/or OPEX. As many mine sites begin transitioning from heap leaching of copper oxides to processing of primary copper sulfides, cost-efficient leach processes that are compatible with existing SX/EW processes will be needed to maintain existing cathode production. To this end, FLSmidth is exploring process options and reactor technology for the hydrometallurgical processing of primary sulfides. One approach that appears to be highly effective at increasing copper recoveries takes advantage of the enhanced reactivity of transitory, surface-defect structures generated during particle fracture. Significant process efficiencies are gained by matching the rate of grinding to the rate of electrochemical leaching in Mechano-Chemical leach processes. The patent-pending FLSmidth® ROL process uses a Stirred Media Reactor (SMRt reactor) to achieve copper recoveries of 97+% in 6 hours or less. This approach overcomes many of the surface passivation problems that have hindered other atmospheric leach processes. New insights to leach mechanisms are presented.

Jan 1, 2015

By Jesús L. Valenzuela, José R. Parga, Salvador Aguayo, Héctor Moreno

The Merrill Crowe zinc-precipitation process has been applied worldwide on a large number of operations for the recovery of gold and silver resulting in a higher consumption of zinc dust from cyanide solutions. However, in some of plants this precipitate is of low quality, because lead, cadmium and especially copper are precipitated along with gold and silver. The low quality precipitate also requires more fluxes in smelting and shortens crucible life. In this study, a process is introduced to remove copper, silver, lead and cadmium from barren solutions following the Merrill-Crowe process. Copper and silver are removed by precipitation in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. The recovery of lead and cadmium ions with natural hydroxyapatite using cow bone powder (CBP) as a new adsorbent material, is introduced. CBP is capable of removing lead and cadmium ions from aqueous cyanide solutions with 99% efficiency. It has the ability to compete with other existing commercial adsorbents for the removal of lead and cadmium. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 99 %; and for the cyanide associated with copper cyanide complexes, the recovery was 90%. Finally, the precipitate quality was improved 400% .This procedure was successfully run at three mines in México.

Jan 1, 2014