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By S. K. Dimitrov

?Ellatzite Med? is one of the biggest mining companies in Bulgaria, processing about 12,000,000 t of ore per year. Waste materials left after extraction of copper concentrate are deposited in tailings dam ?Benkovski 2?. The hydraulic structure is built according to the downstream method, through hydrocyclonization where the downstream batter and the body of the wall are formed by the separated coarse sand particles of the separated tailings. In connection with the prolonged concession of Ellatzite Med and the enlarged capacity of Benkovski 2, the tailings dam has expanded on to the surrounding terrain. To guarantee a normal hydrocyclonization and build up of a tailings wall during waste deposition from the ore mill, the technological scheme of the hydraulic transport system of Benkovski 2 has been changed.

Aug 1, 2013

By Kevin Azocar, Jim Hazzard

"Slope stability analysis is performed most commonly using limit equilibrium calculations or numerical models assuming a two-dimensional slice through an infinitely long slope surface. In areas such as open pit mining, where most slope surfaces are not planar, the importance of curvature becomes important due to the economic gains associated with creating a steeper slope. With advances in computing capabilities within the last decade, three-dimensional slope analysis can be performed within reasonable time frames. Some work has been done on the potential importance of curvature on slope stability, mainly assuming homogenous materials with a circular shear-failure mechanism. However, many open pit mines are excavated in jointed rock mass where a completely different set of failure mechanisms can be seen. Depending on the geometry and radius of the pit, the curved geometry may influence the factor of safety and failure behaviour compared to a two-dimensional slice.A series of numerical analyses were performed to investigate the effect of curvature on jointed rock slope stability compared to an equivalent two-dimensional slope analysis. By using discrete element method models, the influence of joint planes and interaction between distinct blocks can be seen. With a three-dimensional model, the effect of curvature can be combined with multiple joint sets at any orientation, which cannot be seen in a single slice. Numerous three-dimensional models are created, along with an equivalent unit-thick slice. The effect of curvature on a variety of different types of failure mechanisms is observed, and graphical relationships are created to quantify the difference between the three-dimensional factor of safety and the two-dimensional factor of safety based on the degree of curvature."

Jan 1, 2015

By A. M. L. Cushing, S. Kelebek, A. Ghahreman

Iron sulfides are part of many ore deposits affecting flotation separation of non-ferrous base metals from them. Open-circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) measurements were carried out with pyrite and pyrrhotite electrodes to investigate their reactivity under various flotation conditions, which involved the use of TETA, SMBS, and their combination. TETA was found to adsorb on the electrode surfaces causing a significant increase in charge transfer resistance of the product formed, which was most significant at OCP. This effect is much less with SMBS, indicating its greater surface reactivity compared to TETA. The combined use of these reagents decreases charge transfer resistance to a greater degree than that experienced with their individual uses. Addition of Cu2+ as a potential activator to this system nearly eliminates the action of TETA on the electrode surface, which can be attributed to sequestration/chelate formation in liquid phase. The relative effects of these reagents on pyrrhotite electrode are similar to that of pyrite. The main difference between the pyrite and pyrrhotite electrodes is that the observed charge transfer resistance on the pyrrhotite surface with each reagent case is significantly lower by 3 to 4 fold. This is compatible with its anodic nature and ease of oxidation since the OCP value of pyrrhotite is lower than that of pyrite. Results are discussed in relation to flotation/depression behavior of these iron sulfide minerals in mineral separation processes.

Jan 1, 2017

By H. Soto, J. Jara, F. Nava

A method has been developed to recover cyanide and copper from cyanidation effluents contaminated with thiocyanate and copper-cyanide complexes. Copper is precipitated as copper thiocyanate or as copper cyanide depending on pH and the concentrations of thiocyanate and cyanide present in the effluent. The copper precipitate presents good dewatering characteristics and can be easily separated from the effluent by thickening and filtration. The solution containing the bulk of the cyanide is then oxidized with ozone to transform the remaining thiocyanate into cyanide. This results in a regenerated solution rich in free cyanide that can be recycled to the cyanidation process. Careful control of the pH of the solution is required. First pH of the effluent is lowered to optimize the precipitation and oxidation stages, then the pH is restored to an alkaline value to regenerate the cyanide solution. Recoveries of over 96% copper are obtained. Free cyanide in the regenerated solution corresponds to up to 160% of the total cyanide contained in the original impure effluent. (The balance being accounted for by the cyanide obtained by the oxidation of thiocyanate). The efficiency of the thiocyanate oxidation stage is 85% to 90%. The method has been demonstrated at bench scale with effluents of various cyanidation plants of northern Quebec. A preliminary economic evaluation indicates that the procedure would be profitable for effluents rich in copper and thiocyanate. This is the case for most barren bleeds of Merrill Crowe and heap leaching operations and also certain CIP tailings of gold ores containing copper impurities. Environmentally the procedure is a better alternative than the current detoxification methods based on the oxidation of cyanide that do not allow for copper recovery and that have difficulties in producing a final effluent with acceptable levels of contaminants such as ammonia, thiocyanate and copper.

Jan 1, 1996

By G. Brooks, M. Hamed, S. Nightingale, K. Coley

The Marangoni effect plays a significant role in slag line corrosion of refractories. Previous experimental studies for various refractory /slag systems and mathematical models are reviewed and show that Marangoni flow is important in slag line corrosion under static conditions. Recent work by the authors is presented which also shows significant slag-line corrosion of MgO refractory in SiO2-CaO-FeOx-MgO slag. The rate of attack of the MgO was marginally slower in the case of slags containing alumina. A semi-empirical model developed by Hrma based on mass transfer control described reasonably well the observed progression of corrosion with time. Further work is proposed to evaluate this model.

Jan 1, 2004

By E. A. Haack, L. A. Warren

Microbial biofilms are essentially biologically driven, geochemically reactive interfaces between solid surfaces and aqueous solution. Field investigation of acid rock drainage (ARD) associated biofilms at the Onaping nickel mine (Onaping, ON, Falconbridge Ltd.) characterizing: (1) micro-geochemical gradients (pH and 02) (2) metal fractionation amongst biofilm solid components, and (3) microbial communities; over both seasonal and diel timescales, indicates biofilms are highly metal reactive. Results show that biofilms accumulate metals seasonally within two microbially controlled solid fractions: amorphous hydrous manganese oxide (HMO) biominerals and the organic biofilm matrix. The biofilm geochemical microenvironment, driven largely by microbial activity, dynamically impacts biofilm metal behaviour over diel timescales. These results indicate that microbes can play significant roles in bulk system reactive metal transport. On-going investigation seeks to characterize the microbial players and the microbial-geochemical linkages involved in Mn oxyhydroxide formation and subsequent metal sequestration, with the goal of engineering this microbial activity as a bioremediative approach. This approach will have utility beyond specific application to the Falconbridge Onaping site to ARD mine environments in general, as the likely microbes involved in these processes are typically common across ARD systems.

Jan 1, 2004

By C. Phan

This paper outlines opportunities provided for enhanced management and process control by ISA PROCESSTM technology. ISA PROCESSTM technology has the core advantage of offering the potential for vastly improved electrode handling systems. This fundamental characteristic has enabled ISA PROCESSTM technology to develop management and process control systems that are modular, minimalist in their complexity and tailored to a tankhouse operating environment. A review will be presented on the current status of management and process control in ISA PROCESSTM tankhouses covering the central issue of electrode handling as well as electrolyte circulation systems, voltage monitoring, cathode plate tracking, and product tracking. Particular reference will be made of the recent development by Xstrata Technology (XT) and their technology partners, VRT Systems, of an Radio Frequency Identification (RFID) based solution for tracking ISA PROCESSTM cathode plates. The system encompasses fixed readers which identify plates passing through the stripping machines and the use of sophisticated tracking and database software enabling the development of cathode asset management and operational strategies. The performance of individual plates and batches of plates can be tracked through a full service history.

Jan 1, 2007

By Tatsuya Oki

Tantalum capacitors can be found mounted on printed circuit boards of domestic appliances such as personal computers. These capacitors contain a considerable quantity of expensive metal tantalum and can be detached and liberated from printed circuit boards by impact breakers. In this study, the size and density distribution of the liberated electronic devices were investigated. Then, tantalum capacitors were recovered from other electronic devices using size separation and pneumatic gravity concentration methods. More than 70% of Newton's separation efficiency was obtained for tantalum capacitors. High Newton's separation efficiency could be also obtained for other types of electronic devices such as chip resistors.

Jan 1, 2011

By J-F. Béland, N. Parson

Aluminum extrusions are widely used for automotive crash management systems due to their superior specific energy absorption capabilities, as compared to steel. The Al-Mg-Si alloy series can be readily extruded into complex multi-hollow profiles, as required in crash systems, and can be used to target a range of desired strength levels. This paper focuses on the development of an axial crush test protocol and evaluation of the crush performance of common 6XXX series alloys for a variety of tempers. The observed crush behaviour is then compared to tensile test results.

Jan 1, 2015

By Yun-Soo Lee, Su-Hyeon Kim, Hyoung-Wook Kim, Joon-Hyeon Cha

A7075 aluminum alloys have high strengths but poor corrosion resistance. In order to improve the corrosion resistance, a clad sheet is suggested, that is the A7075 alloy sheet bonded to A1XXX or A6XXX aluminum alloy sheets which are surface layers with good corrosion resistance. Mechanical properties of the clad sheets are determined by the combination of the component layer sheets, and thermomechanical treatment should be precisely designed when the strengthening methods of the core and the surface alloys are quite different. In the present study, three-layered A6022/A7075/A6022 clad sheets were fabricated by roll bonding process. Simplified processes incorporating a twin roll casting were also suggested in order to reduce the processing cost. Several temper methods composed of rolling, annealing, solution treatment, and aging were suggested in order to optimize the mechanical properties of the sheets. The strengths of the clad sheets were compared with the bare A7075 and bare A6022 sheets.

Jan 1, 2015

By John Postle, Maureen Jensen, Marcel Vallee, Bernie Haystead, Dan Hora, Graham Clow

The Committee's proposed standards establish definitions and guidelines for the reporting of Exploration Information, Mineral Resources and Mineral Reserves in Canada and are identified as the "CIM Standards" and referred to as such hereafter in this document. To provide additional clarification to Qualified Persons (QPs), guidelines have been included with the respective definitions. The CIM Standards are applicable to all minerals including industrial minerals, diamonds and other gemstones. Reserve definitions for bitumen, natural gas and oil are not included in these Standards. The CIM Standards are not intended to cover mineral inventory estimates that will be reported to government agencies.

Jan 1, 2001

By Mark Sherman

One of the main functions of a process technology and engineering services provider is to select grinding equipment that will meet the client?s throughput rate target. Prudent risk mitigation strategies would suggest that throughput rate estimates be cross-checked using a variety of techniques. Whilst some comminution circuit designers have estimated specific energy requirements via the manipulation of the Bond specific power equation e.g. Barratt?s Grindpower and OMC?s FSAG approach, other designers have opined that the Bond Indices have no role to play in the calculation of SAG mill specific power. As a result, they have developed their own specific energy estimating methodologies, e.g. SMCC?s Drop Weight based power methodology, SPI, SAGDesign, etc. Each method has its supporters and its critics. The challenge facing the engineering provider is how to nominate an SAG mill based circuit throughput rate estimate when faced with significantly disparate specific energies calculated by the different methodologies. This challenge is exacerbated via the continuing evolution of contemporary circuit configurations such as two stage pebble crushing some of which incorporate HPGR technology as the second stage of pebble crushing. The methodology presented in this paper shows that the Bond Indices are an excellent tool for estimating the specific energy requirements for SAG mills in SAB, SABC and SSS circuits. The method accommodates primary crushed feeds, partial and or fully secondary crushed SAG mill feeds, and emulates the impact of pebble crushing on SAG specific energy. As a result, the new Bond Index based method has provided an additional tool for increasing Fluor?s confidence when predicting SAG mill based circuit throughput rates. Based on this outcome, the author proposes that the decades old conundrum of using Bond Indices to calculate SAG specific energies for SAG mill based circuits has been solved.

Jan 1, 2012

By Yan Yang

The Jinfeng gold mine is one of the three gold mines that Eldorado Gold has in China and it is the second largest gold mine in China. The mine is located in a relatively remote and mountainous area in the southwestern Guizhou province. The orebody is similar to the Carlin type deposit in Nevada. The mill throughput was designed to treat 3,600 tones per day. The ore comes from open pit mining and underground mining, and is fed to one-stage jaw crushing. The crushed ore is stockpiled, reclaimed and then fed to the SABC grinding circuit. After classification with hydrocylones, the ore is floated, and the resultant concentrate is oxidized biologically in a process known as BIOX®. The oxidized concentrate is then washed in a CCD circuit and finally leached with cyanide in a CIL circuit for gold extraction. Jinfeng produces about 180,000 oz of gold per year. This paper introduces operations and modifications of SABC circuit over the past three years, and then describes some technical characteristic of the SAG mill and other circuits in the processing plant. Major modifications and improvements on the SABC circuit are described in the paper, including: 1. Impacts of grinding ball and mill liner with respect to material selection, quality, hardness, manufacturing methods, and interactions between mill liner and grinding ball. 2. Effect of milling operation parameters on milling efficiency. 3. Impacts of SAG mill scats and modifications of grate size to improve mill throughput. 4. Design and construction of a pebble crushing system, and recycle the crushed scats to the SAG mill to improve mill throughput. With the above-mentioned modifications, 20% increase over the design in mill throughput has been realized over the past three years, and operating cost has been significantly reduced. However, some issues still remain, and thus process modifications and technical innovations are still needed.

Jan 1, 2012

By F. Czerwinski

Mechanically fragmented chips of an AZ91D magnesium alloy were transformed into a semisolid slurry within the Thixomolding® system. Microstructural analysis of a material at various processing stages revealed that the cold deformation of the alloy, experienced during chipping, led to the recrystallization and growth of equiaxed grains which were subsequently converted to the globular structures by melting the grain-boundary network.

Jan 1, 2004

By Greg Baiden

Telerobotics focused on mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run? A new Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University. This chair will investigate these questions and many more through a series of experiments in a newly established telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian college?s eDome. The laboratory will support many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one/quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments and some preliminary results.

May 1, 2003

By Larry B. Smith

"Feasibility studies are the means by which mineral reserves are established prior to financing a project. However, guidelines are generally lacking for the content, data quality and accuracy of these studies. Regulators take a principle-based rather than prescriptive approach to the content of studies and look to the industry to define study content. Professional organizations, engineering firms and mining companies must eventually establish guidelines and best practices for this work. Most likely these will draw on standards or “stage gates” that have been developed by major mining houses and engineering firms. Engineering studies must: 1.,Define optimal mining and processing methods, production rates, infrastructure, product sales, environmental management and risk mitigation. 2.,Increase confidence in resources, reserves, production plans, processing performance, infrastructure design, environmental management, permitting, capital and operating costs, and financial performance to support financing. 3.,Provide engineering designs suitable for accurate cost estimates. 4.,Develop project execution plans with sufficient confidence that project delays and cost overruns will not occur. Conceptual (scoping, preliminary assessment) Establish the principal characteristics of the project from the geology, resources, metallurgy and development constraints. Assess different approaches to mining and processing. Identify project execution requirements. Test project viability with economic analyses. Recommend additional work to increase the confidence in geology, resources, metallurgical performance, infrastructure, operating and capital costs, environmental conditions and permitting to allow selection of the best development options."

Jan 1, 2003

By J. B. Mawdsley

A LITILE north of the geographic centre of the Province of Saskatchewan, 150 miles north of the city of Prince Albert, is a narrow green-stone and sedimentary belt of pronounced structural characteristics. This belt, generally known as the Sulphide Lake belt, is about two and a half miles wide. During the past three years prospecting has uncovered numerous gold-bearing showings occurring chiefly along the centre of the belt for a distance of at least nine miles. The number of these showings, the nature of some of them, and their relationship to strong structural features, make it altogether likely that intensive work will eventually locate ore-bodies that will be of economic importance. The discovery of gold in the fall of 1938 on the south shore of Mackay lake, about five miles northwest of the Sulphide Lake gold-bearing belt, indicates that there are neighbouring zones of interest. This paper, an attempt to outline the present status of the interesting mineralized belt, is based largely on the information gained on a five-day tour of this district, made in August, 1939, on behalf of the Department of Natural Resources of the Province of Saskatchewan. The Sulphide Lake belt is named after a small lake centrally located in it. This lake and others are just north and within short portage distances of some of the long bays along the north shore of Lac La-Ronge, an irregular, island-studded lake, about twenty miles in diameter, in relatively rocky Precambrian country, just north of the Palaeozoic contact. The fur-trading post and settlement of Lac La-Ronge is on the west shore of this lake and a road, now under construction, will shortly link this community with the city of Prince Albert. In the past, the most direct route was an indifferent canoe route, in part following Montreal lake and river; more recently, the aeroplane has made this section easily accessible.

Jan 1, 1940

By Ray Holmes

This paper describes one approach in our search for greater stope efficiency and lower costs. The uppers technique with wagon drills in cut-and-fill stopes was commenced, on an experimental basis, in our Sudbury mines in 1961. To date, the method has developed into an accept-ed production operation. This technique minimizes the intermittent aspects of the drilling, blasting, mucking and filling operations associated with other cut-and-fill methods. However, studies show that not all cut-and-fill stopes are suitable for uppers, the governing factors being ore width, dip of the orebody, and ground conditions where large areas of unsupported back remain stable for ex-tended periods of time until rockbolting can be accomplished. Introduction F ALCONBRIDGE Nickel Mines Limited operates seven mines within a radius of 30 miles of the city of Sudbury, Ontario. These mines extend in depth from 1,500 to 6,300 ft. The ore consists of brecciated, massive and disseminated sulphides, and the ore minerals consist primarily of pentlandite, pyrrhotite and chalcopyrite. Widths are generally irregular and vary up to 150 ft. The ore dips at between 35 and 90 degrees.

Jan 1, 1965

By C. M. Campbell

The Inconceivable Wealth propaganda goes on apace. Premier King, at Vancouver, has stated that we still have, untouched, natural resources, "beyond the wildest dreams." Principal Currie, in an address before the Canadian Society in New York said that Canada's resources, "are as yet merely scratched and it is not possible to compute her almost fabulous natural wealth." Mr. Meighen, in the last election campaign announced that, "under the providence of God, Canada is more richly endowed, perhaps, than any other country in the world." Four years ago a despatch was sent to Premier King "on behalf of" this Institute advising him that "Inconceivable Wealth" in minerals in this country was assured. This was made as a statement ~f "incontrovertible fact." Specifically, this despatch stated that this wealth was on such a scale that the mining industry would in the future lead all others in this country. This inventory is still in effect as far as this Institute is concerned.

Jan 1, 1926

By T. Richard Davies

This paper primarily deals with the application of wearfacing materials and their role within a well-established preventive maintenance welding program. Some examples are shown, as well as a synopsis of possible benefits and a compendium of methods and materials.

Jan 1, 1979