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By George P. Demopoulos, Amani Al-Othman, Terry C. Cheng

One critical issue in chloride hydrometallurgy is the regeneration of the lixiviant HCl that is currently achieved by pyrohydrolysis. In this paper, a low temperature HCl regeneration process was investigated which regenerates HCl and produces saleable gypsum. This process promises to reduce the generation of wastes by the reaction of spent calcium chloride leach liquors with sulfuric acid solution at low temperature. Experiments were performed to determine the optimum conditions of the reaction in terms of temperature, reagent concentrations, rate of reagent addition, mixing and seeding/recycling to produce marketable gypsum and HCl with practical strength.

Jan 1, 2004

World copper electrowinning tankhouse plant practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in 1995, 1999, 2001, 2002 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automated cathode handling machines, fully automatic cranes and polymer concrete cells. Designs also have included larger electrode sizes and higher electrolyte flows and current densities. Overall these trends have further resulted in optimized tank house productivities and improved electrowon cathode purity. Most greenfield copper electrowinning projects are occurring in South America and Central Africa.

Jan 1, 2007

By M. Moats

World copper refining tankhouse practices have been surveyed. This survey is a supplement to previous surveys that have been carried out in the 1987, 1991, 1995, 1999, 2001 and 2003. On a world basis, process technology trends include the further installation of automated electrode handling systems including permanent cathode systems, automatic anode preparation and cathode handling machines, section switches, fully automatic cranes and polymer concrete cells. General plant process control has increased with more automation of material handling in the copper refining tankhouse. The general trend for most greenfield copper refining projects remains in eastern Asia.

Jan 1, 2007

By R. Anthony Hodge

Who/what is ?community?? What are most communities interested in, what do they care about? What has happened in the past? What is happening today? What is hoped for tomorrow? What are the lessons and keys to success?

May 1, 2006

By CRO CRO

Elk Valley Coal?s Cheviot Project is located in the Alberta foothills south of the town of Hinton. The mine has been in operation now for the 3 years. The start up and subsequent operation of the Cheviot project has been directly influenced by the Cardinal River Mine. As the Cardinal River Mine was winding down due to reserve depletion in 2004, the price of seaborne traded metallurgical coal jumped to record levels and customers began aggressively seeking new sources of supply. Several months later, the owners of Elk Valley Coal decided to begin mining at the Cheviot mining area, extending the life of the area?s operations by over 25 years. The Cheviot Project had been delayed by low coal prices, ownership changes and a complicated and lengthy regulatory process fueled in large measure by stiff opposition from a number of major environmental organizations. Chief to the startup of the project was the construction of a 23-kilometer-long haul road that would connect the new coal measures to the existing Cardinal River processing and rail facilities. Construction of this road was completed with the first coal truck making its first trip in October 2004. This paper will look at some of original assumptions, the actual mining experiences and the lessons that were learned while moving from the drawing board to the current development as it exists today.

May 1, 2007

By Mohammad Mehdi Salarirad

Fouling of activated carbon by different organic species is a great concern in carbon in pulp and carbon in leach circuits. The rate of gold adsorption onto activated carbon from synthetic gold solutions which contained different amounts of potassium ethyl xanthate (PEX), potassium isobutyl xanthate (PIBX), and methyl isobutyl carbinol (MIBC) were evaluated through batch adsorption tests. The results of these experiments showed that the gold sorption rate rapidly decreases by increasing the concentration of collectors including PIBX and PEX up to 20 mg/L and at higher concentrations, the kinetic rate constant (i.e., k value) gradually leveled off to 53 h-1 for PIBX, which is 46% lower than the 99 h-1 for PEX. At low concentrations of up to 15 mg/L of MIBC, a gradual decrease of the rate constant was observed, while at higher concentrations, the decrease was found to be more pronounced. The gold loading capacity and the rate of gold adsorption onto activated carbon from a gold cyanidation pulp in the presence of flotation reagents were also evaluated. The results of these experiments showed that the flotation reagents have no significant effect on the gold loading capacity of activated carbon at prolong adsorption period, meanwhile the rate of gold adsorption continuously decreases by increasing the concentration of flotation reagents in the leaching solution.

Oct 1, 2011

By N. Maleki

Magnesium matrix composites are widely used in automotive and aerospace industries for achieving higher performance due to their light weight. The Mg2Si intermetallics compound in Mg/Mg2Si composite exhibits many excellent properties such as high melting temperature, high hardness, and low thermal expansion coefficient. However, under normal cast conditions, the primary Mg2Si phase exhibits coarse Chinese script or dendritic morphologies and the eutectic structures is very brittle resulting in the low ductility and strength of the alloys. Modification treatment is a very effective method to obtain fine microstructure and improve the mechanical properties of the alloys due to low production cost. In this investigation various amount of bismuth addition have been carried out on Mg?5wt %Si alloy to refine and modify the morphology of coarse Mg2Si in order to improve the corrosion resistance of the composite product. The effect of Bi content on microstructure of Mg2Si/Mg composite was investigated by optical and scanning electron microscopy followed by EDX analysis and X-Ray diffraction. In order to compare corrosion resistance of unmodified and modified specimens, Immersion test and potentiodynamic polarization (PD) were used. The results showed that by Bi addition, the size of primary phase Mg2Si was considerably reduced and the morphology was modified from a coarse dendritic shape to a polyhedral shape. The results also indicated that the corrosion resistance of Mg?Si alloys was improved by the addition of 1%wt of Bi due to the reduction, refinement and evenly distribution of Mg2Si phase. Indeed, both the morphology and distribution of Mg2Si intermetallic had a great influence on the corrosion behavior of Mg/Mg2Si composite.

Oct 1, 2011

By Mitchell Gordon

"In almost all thickener applications the highest possible solid/liquid separation efficiency is what is desired by the user. There is a trend in the industry due to monetary restraints and environmental pressures to look at ways to extract this maximum performance by either retrofitting existing thickeners or installing the most cost effective new thickener. This paper looks at some of the common problem areas and presents a range of solutions developed by Outokumpu Mintec in North America and outokumpu's subsidiary Supaflo Technologies Pty. Ltd.The Emerging PictureAfter many hours of discussions with a large number of plant personnel over the last two years a picture began to emerge regarding current thickening operations in the industry. Initially, it seemed that everybody had their own unique process problems and therefore needed a correspondingly unique solution. Looking more closely at all the cases and the ideas that we had either implemented or suggested, it gradually became apparent that the majority of operators all had one and the same process need ....""Better Separation Efficiency""The range of operational problems that were uncovered in the survey were much more varied than expected and often were not even considered initially to be thickener problems. Often, it was only after the rejection of many solutions to the problem, generally due to capital cost, that the actual cause of the problem was looked at and found to be a thick-ener.A summary of the problems that have so far been identified is presented in Table 1. They are subdivided under three major categories of environmental, process and paste fill to highlight the wide range of mining activities that can be affected by poor thickener performance. These seem to be the major areas where the need for better separation efficiency is rooted."

Jan 1, 1995

By J. W. Jefferies

"Plant availability up 13%, production output up 40%, tons per employee up 15% and labor turnover down 52%. One mine manager states these were direct spin offs from the work being done to qualify for a safety award in the program known as the ""IMSRS 11 over a three-year period of time. ""Of Course"", stated this manager, ""these were in addition to an 87% reduction in our disabling injusry frequency rate.”Officially known as the International Mine Safety Rating System or the Five Star Mine Safety Rating, a new approach to mine safety is being used with enthusiasm by a significant number of mines in Canada, the U.S., Australia, Chile, Indonesia, the Philippines and South Africa. Significant results are coming into the International Loos Control Institute from over 125 mines from these countries.The program is built around a mine safety audit system that gives positive recognition to a mine at 5-step intervals along the way, (a star with each step attained). The Institute has licensed auditors in locations in Canada and the U.S. available to audit.It is believed the success of this program is the result of the premise upon which the program is based. The results being achieved are due to the concept that a modern, well-managed mine safety program maintains the basic foundation of a complete management system. When properly implemented, it reinforces those factors common to production, quality and safety. (Attitude - skill - knowledge - fitness - structure - machine - equipment - materials and processes). The IMSRS contains elements that reinforce all these factors. It uniquely treats safety as part of the ""right way"" to do the job and not just the ""safe way"" as a distinctly separate entity. Mines using this program now recognize that many of the older safety techniques were not necessarily the right way or the most efficient way to do things. It appears that this new approach to mine safety is a new avenue for the attainment of management's real goals for being in business, and at the same time achieves optimum support for the important target of safety and health for the mine worker."

Jan 1, 1983

By E. C. De Matos

The Uranium Province of Lagoa Real is located in the mid-south region of Bahia State, Brazil. Uranium is the only mineral wealth, occurring mainly in the form of uraninite. The region has been searched for uranium since 1971 and 35 anomalies were detected, distributed over 1200 km2. Seven are now taken as deposits, accounting for reasonably assured resources of 100.000 tons of U3O8. This paper describes the geological aspects of the area, the exploration and mining activities done so far by the state company INB and the perspectives for the near future, when a raise in the country?s uranium demand is expected.

Aug 1, 2010

By Kousuke Takahata, Hirofumi Yoshimura, Jun Nakahigashi

Studies of a protium treatment for grain refinement of a + ß type titanium alloy are reviewed and recent experimental results are introduced. Protium treatment consists of the following three processes: (1) protium absorption, (2) martensitic transformation and hot working, and (3) final treatment for protium desorption and recrystallization. A combination of these processes results in the ultra-fine grains of 0.3 to 0.5 µm in diameter with high angle boundaries. The ultra-fine-grained material exhibits superplastic elongation of over 9000%. Superplastic forming was successfully used to fabricate a denture base. These materials may be widely applicable as biomaterials in various medical industries.

Jan 1, 2004

By Y. Dong, L. Li, L. Yu

Converter slag has become an important secondary raw material. Consequently, vanadium bearing converter slag is of great interest for the recovery of vanadium. Solidified converter slags are made up of three main mineral components: dicalcium silicate, calcium ferrite and wustite. Vanadium in modified slow cooling down converter slag of Magang is found mainly concentrated in a separate mineral phase. The mineral phase with high content of vanadium (24%, wt, V205), concentrating 83% of vanadium, can be separated from the slag for economical vanadium recovery. Some characters of the mineral phase were discussed comparing with dicalcium silicate, one of the typical mineral phases in converter slag studied well.

Jan 1, 2004

By Z. S. Abisheva

The Zhezkazgan copper sulfide ore deposit in Kazakhstan contains both rhenium and the rare osmium isotope "osmium-187" (187Os) in the high isotopic purity of 99.4 ± 0.2%. This isotope is believed to have originated as a result of the disintegration of one of the rhenium isotopes, according to the reaction: 187Re75 ?> 1870576 + B- + v~ (where B is a 13-particle, v~ is a 3-disintegration antineutrino). The distribution of osmium and rhenium in metallurgical byproducts produced during the recovery of copper from these ores has been studied and process flowsheets for the processing of rhenium and osmium-containing byproducts have been developed.

Jan 1, 2007

By V. Ramachandran

The successful advent of solvent extraction (SX) reagents for copper recovery and improvements in electrowinning of copper to produce LME grade A copper cathode have paved the way for the hydrometallurgical treatment of copper oxide and low grade sulfide ores. This has resulted in about 25-30% of the world's copper being produced today by the Leach-SX-EW process. The obvious next step was to develop processes for the hydrometallurgical treatment of copper sulfide concentrates, as an alternative to a typical smelter-refinery complex. The current paper updates the processes that have been developed to date with emphasis on processes that are being commercialized or that are seriously under consideration for commercialization. Most of the discussions relate to the hydrometallurgy of chalcopyrite concentrates, which account for about 70% of the world's known copper reserves. In summary, in the last thirty years, the hydrometallurgical treatment of copper sulfide concentrates has attained full maturity and will be a serious option to contend with while evaluating any future new copper plant.

Jan 1, 2007

By R. V. Kumar, F. Tailoka

In order to use ZnO laden dust as a possible desulphurization reagent, it is important to evaluate thermodynamics of the Zn-O-S system. At temperatures greater than 1450 K, there is an uncertainty in the thermodynamic data for the reaction of zinc with sulfur to form Zinc sulfide. In this work, the standard free energy has been determined using an electrochemical cell: Pt, Mo, MoO2/YSZ/ZnO, ZnS, S02, Pt., between 1198 and 1602 K. AG° varies from -145,880 to -88,100 J (± 2500) , with a phase change to ZnS (g) by sublimation occurring between 1450 and 1460 K. This is supported by thermogravimetric analysis which shows about 80% weight loss in ZnS from 1273 to 1473 K. Feasibility reactions were also performed and confirmed that ZnS (g) is formed when ZnO reacts with FeS (1473 to 1653 K) or with Fe-Csat-S(1473-1673 K). There is therefore potential for the utilization of ZnO laden waste as an additional or alternative reagent for desulfurisation.

Jan 1, 2004

By G. E. Wood

THE INSTABILITY of copper prices and their low levels since late 1974 are of great concern to both producers and, to a lesser degree, consumers of copper. The price levels portrayed by the "neutral long-term" price trend are assumed to have been enough to encourage sufficient investment to provide adequate world production capacity and yet not so high as to encourage development of excessive over capacity. The identification of the present level of this trend has taken on special importance for governments and for corporations active in the world copper industry. One approach to the possible determination of such a price is through the use of moving averages. In this way, the effects of relatively short-term price movements can be dampened, as can those related to business cycles. From such averaged price data, long-term trends can be sought over a selected time period. The choice of the past time period for which a price trend is sought may have a major effect on the result'. For example, in the period 1885-1973, the long-term price trend for copper in constant dollars showed a decline, whereas in the period 1919-1973 it was rising. For the purposes of discussion, an appropriate choice of period might be a relatively short and recent one so that the majority of the present cost factors would be present throughout. It should also be long enough to cover a number of full business cycles.

Jan 1, 1977

By P. B. Demarsh

"Location: - On highway 59, 17 miles east of Val d 10r near junction of Montreal highway in Northwestern Quebec.Life; - Started production 1952, ceased 1965.Ore: - Pyrite, chalcopyrite and small amounts of free gold and goldsilver tellurides in narrow quartz-carbonate-tourmaline veins in granodiorite. Specific gravity 2, 70.Capacity: - 700 tons daily Bevcon ore supply, l 000 tons daily when custom ore available.Assay: - Heads 0 .140 oz. per ton; tails 0. 009 per ton; extraction 92.5%.Grind: - 75% minus 200 mesh at 700 tons; 68% minus 200 mesh at 1000 tons. Detention time 28 hours and 21 hours respectively.Treatment: - Cyanidation process.Reagents: - Per ton. Aero Cyanide (NaCn) 0, 50; crushed unslaked lime 1. 75; zinc 0. 03; litharge 0. 10; steel consumption 2. 25.Water: - Pumped from land-lock spring fed lake l 1/2 miles distant.Cost: - Per ton. Crushing 0. 13; grinding 0 .32; filtration 0. 07; cyanidation 0.14; miscellaneous 0.29; total 0.95.Power: - Hydro-electric, 25 cycle, 12, 000 volts reduced to 550 volts.Labour: - Predominantly French Canadian, nucleus English Canadians.Tailings: - Impounded low lying pond.Personnel: - 15 including supervision.Flow sheet: - Canadian Mining Manual l 9 5 6 .Building: - Wood truss construction: 3/ 4 in. siding, ten test and 1/ 4 in. transite outside. Corrugated galvanized iron roof. Ground level foundations. Internal self induced heating. Wood stave tank equipment."

Jan 1, 1966

By A. A. Sirkeci, M. Tarkan, N. Acarkan, O. Kangal, G. Bulut

This investigation deals with the evaluation of the tailings of the Kirka Borax Plants. In this respect boron in the tailings was recovered and the utilization of the clayish fraction was investigated. There are five tailings ponds in Kirka four of which are used for the tailings of the borax concentrator and the remaining one is used for the tailings of the sodium penta-borax plant. Experiments were conducted with samples taken from ponds containing coarse fraction and fine fraction. Coarse fraction of Borax Concentrator were screened through a set of sieves. The fraction above 1 mm was removed with 41.5% recovery and 33.3% B203 content. Scrubbing was applied above 0.1 mm and products containing 32 to 34% B203 were obtained with recoveries around 35%. The tailings of sodium penta borax plant was also screened and it was found that 15% of boron reported to +1 mm size fraction with 35% B203 content. Sample containing fine tailings was treated by cycloning. The cyclone overflow was found to be below 6µm and it was separated to be used in the subsequent tests. The usage of cyclone overflow in paper, ceramics, glass, pigment and drilling industries was investigated. Since this fraction is mainly composed of carbonate minerals rather than clay minerals it was suggested that it may be used for construction and moulding purposes. Furthermore, the B203 content of the cyclone overflow was reduced to 2.4%.

Jan 1, 2004

"This document sets out the Exchange’s expectations and requirements for a valuation of mineral properties and outlines: the general purpose of valuation reports; guidelines respecting circumstances where the Exchange will require a valuation report; and valuation standards, guidelines and methods that are generally acceptable to the Exchange, 1. IntroductionThis Appendix sets out the Exchange's expectations and requirements for a valuation of mineral properties and outlines:(a) the general purpose of valuation reports;(b) guidelines respecting circumstances where the Exchange will require a valuation report; and(c) valuation standards, guidelines and methods that are generally acceptable to the Exchange.Mining industry standards and guidelines for valuations and valuation reports can be found in the Canadian Institute of Mining, Metallurgy and Petroleum Standards and Guidelines for Valuation of Mineral Properties (""CIMVal"") published in February, 2003 (www.cim.org). CIMVal consists of two parts, Standards and Guidelines. The Standards are mandatory and must be followed in order for a valuation to be CIMVal compliant. The Guidelines in CIMVal are not mandatory, but are strongly recommended.The Exchange requires that CIMVal Standards be used by Issuers and their professional advisors when preparing valuations and valuation reports on mineral properties. The CIMVal Guidelines should be followed by Issuers and their professional advisors in preparing valuation reports on mineral properties, with the exception that the valuation methods and guidelines under Section 4 Acceptable Valuation Methods and Guidelines below, must be followed."

Jan 1, 2003

By Yasuhiro Aoki, Akihiro Sato, Mikiya Arai

In this study, a freckle formation model based on the Rayleigh number was applied to actual multi-component Ni-base single crystal superalloys and verified in large scale casting trials. Finally, new Ni-base SC superalloys having a balance between castability and creep strength has been developed.

Jan 1, 2010