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By W. H. Moore

It seems necessary, at times, that we should reconsider some of the more obscure causes that lead to explosions of gas and coal-dust in mines, in the hope that a recapitulation will keep before us that old and true saying "eternal vigilance is the price of safety". This explosion, while not extensive (resulting in only two much to be regretted deaths) enlarged our vision as to the possibility and probability of other explosions with more disastrous results. As this is only a partial report I shall have to omit many things that are generally included in describing a mine explosion. The mine was worked exclusively with electric cap-lamps -only firebosses and other officials carried safety-lamps. All shots were examined and fired by firebosses with a small hand-battery. Monobel was used exclusively for blasting, and clay for tamping. The system of haulage iri use was main-rope and winches, horses being employed for gathering. Compressed-air was the motive power for all winches and pumps, excepting the pumps at the shaft-bottom which were steam-driven. The mine was wet with practically no dust anywhere, except what was being made at the coal-face in the getting of the coal. Gas was found occasionally, generally in the brushing, especially where the brushing was carried up to a small seam, 2 to 6 feet above the main seam. The place where the explosion took place was known as Leigh's heading, which was being driven to the rise, immediately inbye of the siding (off No. 1 left, off the new slope) and was about 90 feet up from the level.

Jan 1, 1926

The 14MW SAG mill at Tarkwa, Ghana, experienced a frozen drop charge incident on 10 February 2010. This caused downtime of 112 hours, a repair cost of $200k and production loss of 162,000 tons, corresponding to a loss of $8.9M. A new locked charge protection system was installed on the two Tarkwa mills on 30 July 2010, mitigating this risk. This system calculates the ore angle in real time while the mill is starting up and trips the mill if the ore angle exceeds a trip angle setting. The calculation of the ore angle is derived from the mill motor rotor currents only - no mechanical transducers are required. The head of Gold Fields West Africa, Peter Turner, says of the new system: "This is excellent work and the type of technology that has had and will continue to have, major opportunity cost impacts on our business."

Jan 1, 2012

By X. Cao, A. Birur, R. R. Chromik, J. Cuddy, P. Wanjara, J. Gholipour Baradari, T. Shariff

In this study, 3.1 mm thick Ti-5553 (Ti-5Al-5V-5Mo-3Cr) butt joints were autogenously welded using a 4 kW continuous wave Nd:YAG laser. The effect of welding speed and defocusing distance on the weld quality was investigated in terms of the surface morphology, welding defects, microstructure and hardness. Welds with full penetration were achieved at a defocusing distance ranging from -1 mm to 0 mm and welding speeds from 2.25 to 6.0 m/min. Underfill and porosity were the two main defects most frequently observed but within the optimum process window these defects could be maintained to meet aerospace specification tolerances. The fusion zone (FZ) consisted entirely of retained beta with a refined dendritic morphology. Compared to the bimodal alpha (a) + beta (ß) microstructure of the base metal (BM), the dissolution of the a phase was observed in the heat affected zone (HAZ), which led to an 11 % decrease in hardness from the BM to the FZ. To determine the tensile properties of the welded samples, an automated 3D deformation measurement system was used to measure the local strain in the weld region. The yield strength (YS) and ultimate tensile strength (UTS) increased with increasing welding speed with a highest joint efficiency of 75 % being achieved, albeit with a concomitant reduction in the ductility.

Jan 1, 2010

By M. F. Gallerneault, V. Fallah, A. Howells, W. M. T. Gallerneault

"The occurrence of recrystallization in cold-worked aluminum sheet during the brazing process leads to loss of strength, an inhomogeneous grain structure and reduced corrosion resistance. AlMgScZr alloys are known for their extraordinary recrystallization resistance due to the influence of Sc and Zr addition on their microstructure. Here, we investigate the effect of alloy composition (i.e. Mn, Mg, Sc, Zr content), cold-roll reduction and pre-aging treatment on the recrystallization behavior of cold-rolled sheets at brazing temperatures typically used during the manufacture of heat exchanger units. The analysis of recrystallization behavior is carried out through microstructural characterization and the results are compared with the behavior of a commercial, AA3xxx-based heat exchanger alloy.INTRODUCTION Control of recrystallization is of critical importance during brazing, which is a widely-used joining technique for aluminum alloys in aircraft structures (Heinz, 2000) and automotive heat exchangers (Miller, 2000; Marshall, 1993). Due to excessive local heat at brazing temperatures, the cold work texture of aluminum alloys in the cold-rolled sheets may undergo a local recrystallization process (Marshall, 1993). This leads to the formation of an inhomogeneous microstructure and thus anisotropic mechanical properties (Miller, 2000) and low corrosion resistance (Marshall, 1993) across the sheet. X800, a commonly-used Al-Mn alloy series for automotive heat exchangers applications, has been developed specifically for a higher strength as well as an enhanced corrosion resistance as opposed to the traditionally-used AA3003 alloy (Marshall, 1993). X800 alloys, however, exhibit a low recrystallization resistance at normal brazing temperatures, i.e. 590°C. In contrast, Al-Sc-Zr alloys have been shown to exhibit an extraordinary recrystallization resistance at such temperatures (Riddle, 2004) while also being corrosion resistant and possessing a high room-temperature strength (Fuller, 2002). This has been shown to be due to the formation of coherent, nanoscale Al3(ScZr) precipitates that effectively impede grain boundaries while also exhibiting very slow coarsening kinetics at high temperatures (Riddle, 2004; Jones, 2003; Ocenasek, 2001). In this study, we analyze the recrystallization behavior of X800 alloys under brazing conditions through introducing Sc and Zr into the system as well as varying the Mn and Mg content. The effect of processing route is also studied by introducing a pre-aging stabilization treatment as well as varying the cold-roll reduction prior to the final brazing anneal."

Jan 1, 2018

By Dennis Hoffmann

"Abstract - Banded iron formation rocks associated with massive sulfide lenses in the Broken Hill Pb-Zn-Cu-Ag deposit in the Namaqualand Metamorphic Complex, South Africa , were investigated with respect to the geochemistry of manganiferous silicate-rich bands. Two common varieties of these are: amphibole- and garnet-rich iron formation bands. The results reveal that the former are enriched in Fe, Mg, Cu, Co and S. The garnet-rich bands are enriched in Mn, Ca, P, Pb and Ba with significant detrital contamination of Ti, Al, Zr, Cr, Y, V, Ni and Nd.The silicate-rich bands have compositions, in terms of, Si/Al, Si/Fe, Fe/Mn, La/Ce and Co/Zn, comparable to submarine chemical sediments which precipitated from hydrothermal fluids. The garnet­ and amphibole-rich bands are interpreted as ""evolved"" and ""immature"" hydrothermal sediments, respectively. The latter resulted from rapid precipitation after exhalation, whereas the former had a longer residence within sea water. The silicate-rich bands both exhibit increasing Mn/(Mn+ Fe) fractions, which are consistent with a variation expected from proximal to distal depositional settings. The prevalence of garnet-rich bands over amphibole-rich bands is interpreted as the result of injection of hydrothermal fluids from a single vent situated along the northwest margin of the Broken Hill deposit."

Jan 1, 1994

By F. Ajersch, M. Rigaud, M. Jallouli

"Le gonflement des boulettes d'hématite à été étudié à l'aide d'une méthode de mesure standard ISO ainsi qu'à l'aide d 'une méthode de mesure dilatométrique.La première méthode a servi à l'étude des boulettes haute silice (5% SiO2) dont l'indice de basicité (IB = CaO + MgO -i- SiO2 + Al2O3) a été ajustée soit à l'aide d'une addition de dolomie, soit à l'aide d'une addition de pierre à chaux, soit à l'aide d'une addition de ces deux composes. L'indice de basicité variait de 0.05 à 0.12. Les résultats de gonfle ment obtenus à 1000?C dans une atmosphère de 40 CO - 60 N2 ont permis de montrer qu’indépendamment de l'indice de basicité c'est la dolomie qui contribue le plus à diminuer le gonflement par rapport à la pierre à chaux. L'utilisation de l'indice de basicité comme critère de sélection des boulettes est discutée.La méthode dilatométrique a servi à l'étude du gonfle ment de deux types de boulettes préparées à partir de deux concentrés de fer et dont la teneur en silice a été fixée à 2.5% et 0 5%. Ces deux types de boulettes ont reçues les mêmes additions de liant en quantité et en nature. La détermination en continue du gonflement, à 950?C dans 40 CO - 60 N2, a permis d'une part de mieux cerner le niveau de réduction auquel correspond le maximum de gonflement et d'autre part de montrer que l’allure des courbes de gonflement est étroitement liée à la nature du liant. Une augmentation de la teneur en silice des concentres contribue à diminuer le gonflement des boulettes.Des essais de réduction de gonflement non isothermes ont été réalisés à des montées de température à 10 et 20?C/min. Les résultats indiquent que le gonflement déterminé dans les conditions non iso thermes est inferieur à celui obtenu lors des essais isothermes. On discute alors de la validité des essais standards de gonflement qui sont utilisés pour prédire le comportement des boulettes lors de leur réduction dans un haut fourneau."

Jan 1, 1983

By Z. Ren, M. Tomlinson, E. Asselin

"Organic carbon blinding is a common, yet often partial, solution to the reduction of preg-robbing. A quantitative method to assess the extent of adsorption of a given blinding agent is presented herein. The adsorption of several blinding reagents on various carbon samples is quantified using electrochemical impedance spectroscopy (EIS). EIS results showed that kerosene is more strongly adsorbed on carbon than sodium lauryl sulphate (SLS), while SLS can hinder the charge transfer process of the oxygen reduction reaction on the carbon surface more effectively. The effectiveness of SLS is pronounced when its concentration is higher than 100 ppm. Raman spectra are presented for selected carbon samples: as the area ratio of the disordered peak to the graphitic peak increases, blinding agent adsorption increases.INTRODUCTION The presence of naturally occurring constituents in gold ores may adversely affect the extraction of gold in cyanide leaching since the gold cyanide complex, Au(CN)2–, can be adsorbed by these constituents (M. Adams & Fleming, 1989; Afenya, 1991; Miller, Wan, & Díaz, 2005). Such ores are known as “preg-robbing”. Preg-robbing behavior may arise from natural carbonaceous materials in the ore (M. Adams & Burger, 1998). In the past decades, a number of pre-treating methods have been developed for refractory carbonaceous ores (Arriagada & Osseo-Asare, 1984; Beer, 1994; Dunne et al., 2007; Jiang, Liu, Xiao, & Yang, 2012; Kohr, 1997; Kulpa & Brierley, 1993; Menne, 1992; Menne & Revy, 1994; Moyes & Houllis, 2010; Petrie, Craw, & Ryan, 2005; Simmons, 1996). The method known as blinding is one of the most effective and economical pre-treatment methods (M. D. Adams & Burger, 1998; Albert, 1923; Darrow, 1924; McQuiston & Shoemaker, 1975; Van den Berg, 2000). Blinding, also referred to as blanking or passivation, uses a chemical reagent to passivate the preg-robbing carbon by selective absorption or wetting (Bas, Altinkaya, Yazici, & Deveci, 2012; Brierley & Kulpa Jr, 1993; Dunne et al., 2012; Van den Berg, 2000; Yang, Qian, Song, & Dong, 2013; Yen, Amankwah, & Choi, 2008; Zhou, Jiang, & Choi, 2014). Organic reagents, which selectively adsorb on the surfaces of activated carbon and “smother” the surface, have been used for blinding carbonaceous matter in gold ores prior to cyanidation. Two comprehensive studies by Abotsi and Osseo-Asare and Adams and Burger have been published on this topic (Abotsi & Osseo-Asare, 1986; M. D. Adams & Burger, 1998)."

Jan 1, 2017

By H. A. Pearse

Introduction This paper may be regarded as another instalment of the story of the Britannia milling operation. From time to time in the past, articles (1) have been prepared by various members of the staff, giving details of crushing, grinding, and flotation treatment for the normal Britannia ore. It is not, therefore, the purpose of the present paper further to discuss what may be termed the standard milling operation, but rather to describe a flotation practice which has been evolved directly as a result of the general depression. The normal Britannia ore mixture contains chalcopyrite and pyrite as the main sulphide minerals, together with minor gold and silver values. The standard milling practice, evolved during several years of experimentation, provided for bulk flotation of the two sulphides after primary grinding to only approximately 35-mesh, followed by regrinding of the bulk concentrate, with subsequent separation of the chalcopyrite and pyrite to make a marketable concentrate of each mineral. However, in the face of a constantly increasing surplus of copper on the world markets and a steadily falling price during 1930 and 1931, it was obviously undesirable to continue producing large quantities of this metal at a loss. On the other hand, Company officials were very reluctant to add to unemployment by closing down entirely, provided operations could be continued without excessive losses. Fortunately, the existence was known of a fair sized body of ore, quite low in copper and relatively high in zinc content, with also a very considerably higher gold value than that prevailing in other sections of the mine.

Jan 1, 1934

By L. O. Thomas

THE Alaska Highway, in its course through British Columbia, traverses parts of two great physiographic divisions of Canada which are also distinctive geologically-the Cordillera in the western section and the Interior Plains in the eastern. The Cordilleran region in the portion of the Province with which this paper deals can be divided into four major northwest systems, known respectively from west to east as Coastal, Plateau, Cassiar-Omineca, and Rocky Mountains. The Coastal system consists solely of the Coast range except in the extreme northwest, where a part of the St. Elias range is included. The Coast range, characterized by mountains of great ruggedness,. is made up of an igneous complex of granitic rocks intruded chiefly as a great batholith. In places, spurs of these rocks extend into the Plateau heft, a partly mountainous tract largely occupied by quartzites, quartzose mica schists and their gneissic phases, and crystalline limestone with interbands and broad areas of chlorite, _hornblende, and sericite schists and bodies of intrusive granite gneiss-an assemblage of rocks known as the Yukon group. The Cassiar-Omineca system marks the divide between the Pacific and Arctic drainages. Its eastern boundary is well defined in the south by the Rocky Mountain Trench (see p. 229). The rocks of the system are, miainly, highly altered Palaeozoic sediments, but there are also Precambrian and Mesozoic rocks, the latter largely volcanic. The core of the system is granitic and there is evidence (see p. 221) to support the belief that it is of such a length as to constitute a batholith comparable to that of the Coastal system.

Jan 1, 1944

By Arnold R. Pasieka, George V. Sotirow

"The object of this paper is to outline a computerized net cash flow approach for practical cutoff grade determinations. A cutoff grade carries not only geological but also economic value, in which costs are balanced against revenues. For different situations, cutoff grades are a 'standard of value' that are determined for the purpose of classifying economic or uneconomic mineral reserves in a specified time frame. In a constantly changing technical and economic environment, the decision to develop or maintain a mining operation at its best economic potential, requires an appropriate cutoff grade strategy, a strategy consistent with short- and long-term operational and corporate objectives and one based on realistic marketing and metal prices forecasts. The use of a project evaluation computer program, in combination with specific corporate net cash flow requirements, shows the most promising and flexible team approach for cutoff grade optimization.IntroductionThe recent recession has had a devastating effect on the Canadian mining industry. Exploration and mining R&D expenditures have been critically reduced and now are believed to be below healthy levels. Ore reserves, mine life and cutoff grades are careening in several directions because of low base metal prices, relatively high costs and sensitive precious metal prices.These conditions demand an improved understanding of the terms ""ore"" and ""cutoff grades"" as they are applied to the planning process and day-to-day operations. ""Ore"" or 'ore reserves"" is a dynamic concept, reflecting a cumulative effect of changes in geological, technical and economic conditions in terms of material which can be mined at a potential profit. By contrast, if economics are not the primary consideration, the term ""mineral reserve"" or ""mineral inventory"" should be used to describe the mineral deposit. For different situations, cutoff grade is ""a standard of value"" determined for the purpose of classifying mineral reserves as economic or uneconomic in a specified time frame. The question of mining at average reserve grade or low-grade material during high metal prices is of paramount importance for cutoff grade strategy."

Jan 1, 1985

By Sergei Decterov, Peter Hayes, Evgueni Jak, Taufiq Hidayat, Denis Shishin

Copper smelter operations around the world are under sustained pressure to reduce costs and increase output. Through the provision of reliable data on fundamental properties of the chemical systems the opportunities for improvements of industrial copper production can be identified. Experimental and modelling studies on phase equilibria, thermodynamics of copper slag/matte/metal/gas systems have been combined into an integrated research program undertaken at PYROSEARCH. Experimental phase equilibria studies involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of compositions of equilibrium phases with electron probe X-ray microanalysis (EPMA). Thermodynamic databases development and modelling is undertaken using the computer package FactSage in conjunction with advanced models used for complex solution phases. Progressive development of these research methodologies has brought significant advances in characterisation of these complex systems, including a new optimised thermodynamic database for the copper-containing slag system Cu2O-Al2O3-CaO-FeO-Fe2O3-MgO-S-SiO2.The new data and models can now be applied to assist in improvements of the processes. The effects of changes to chemistry and process conditions within the smelting reactor can be examined. Several examples of new descriptions of the phase chemistry of the Cu2O-CaO-SiO2 and Cu2O-FeO-Fe2O3-SiO2 systems in equilibrium with metallic copper showing calculated and experimental data are presented.

Jan 1, 2014

By A. L. McAllister

"MASSIVE sulphide deposits are found in two areas of New Brunswick, the St. Stephen area and the Bathurst-Newcastle area. In both, the geology in the immediate vicinity of the sulphide bodies is largely inferred from drilling results as outcrop is not plentiful and is, in fact, almost lacking in most places. With few exceptions these deposits have not been explored by underground methods. Consequently much of the. detail on the geology will only become known over a period of years as economic conditions make mining feasible.Much of the information contained in this paper has been supplied directly by company geologists. As a result of the number of contributors, some confusion of nomenclature bas to be anticipated. Cross-sections and plans of the individual deposits are, in most cases, as supplied by the companies concerned. Most of the interpretations are the responsibility of the author."

Jan 1, 1960

By Ian Orford, Ken L. Boyd

"Can the ever-increasing tonnages of ore and waste being mined today be accommodated simply by using bigger and better crushers? This paper updates the principal author’s earlier publication, “Crushing Plant Design and Layout Considerations” (SME Mineral Processing Plant Design, Practise, and Control, 2002). It reviews the latest primary crushing and large cone crusher designs. Its goal is to help consultants and operators select the optimal equipment and custom-designed items in the material handling flowsheet from the mine to the mill, maximizing operating hours per year.INTRODUCTIONAre larger crushers the answer to meeting the demands of existing or new mining projects for increased tonnage? The principal author’s previous paper in the year 2002 on ""Crushing Plant Design and Layout Considerations"" provided a detailed design and layout review for the design of primary and fine crushing (Secondary, Tertiary, Quaternary) mineral processing facilities. Some of the conclusions in this previous paper had predicted that larger crushers for primary and fine crushing would be beneficial and contribute to the further development of mineral processing. Larger crushers for primary and fine crushing applications are now available.The rock size reduction process, from the mine to the selected milling process facility has not changed since man first broke a rock to get at the interesting mineralization within. The rock size reduction process circuit from the mine to the mill can be summarized into four (4) stages:• Stage 1: Mining ( Rock Breakage and Fragmentation)• Stage 2: Pre-Screening (Scalping)• Stage 3: Primary Crushing• Stage 4: Fine Crushing (Secondary, Tertiary and Quaternary; the crushers used in this stage are identified by the titles which usage has conferred on them)Plant throughput and ore delivery schedule will form the basis for flowsheet design and equipment selection. Once a project's design criteria and the mine plan has been established, the actual circuit's utilization percentage (percentage of hours when the circuit is being utilized) can be optimized for each of the four stages. The mining and process departments are the key stake holders in the selection of the final comminution circuit and both departments should be familiar with and contribute to the design of the circuit."

Jan 1, 2016

By Dave Marsh, John Goode, Niels Verbaan, Kevin Bradley, Henrie Notzl

The mineralogy of the Avalon Nechalacho deposit is complex with significant fractions of HREEs, Zr, and Nb found in refractory minerals such as zircon and fergusonite. Sulphuric acid baking followed by water leaching can be used to extract REEs from flotation concentrates, but acid baking does not completely "crack" the zircon and fergusonite, so the extractions of Zr, Nb, and HREEs are not high. An alternative flowsheet has been developed that is able to obtain significantly improved extractions of HREEs, Zr, and Nb from flotation concentrates or acid bake residues. This is accomplished by cracking the zircon and fergusonite minerals with caustic soda at high temperatures, followed by water washing to recover excess caustic soda and soluble sodium silicates and phosphates. REEs, Zr, and Nb in the solid residue can then be solubilized with HCl or H2SO4. This paper highlights some of the findings from an extensive laboratory program and discusses several flowsheet implications.

Jan 1, 2014

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 J. -M. Lalancette, D. Lemieux, C. Chouinard

"A gold bearing concentrate containing 107 g/T of gold, 9.3% copper and 706 ppm of mercury was processed at the demonstration scale for the extraction of gold and copper using a cyanide free process. The concentrate was generated through flotation to upgrade the gold and copper grade, but also showed contamination with mercury. This concentrate was submitted to the DST process demonstration plant. The concentrate was first oxidized using a fluidized bed to produce a calcine. The mercury was volatilized during the oxidation stage with an efficiency higher than 98%. The mercury was condensed and removed from the sulfuric acid using a thiosulphate process. Copper was extracted from the calcine as copper sulphate using diluted sulfuric acid. The solid remaining after acid leaching was submitted to the DST chlorination process for gold extraction. Under optimized conditions, a gold extraction of 97.3% was achieved in the chlorination reactor. Gold was recovered from the pregnant brine by precipitation on silica using a DST proprietary process.INTRODUCTION Dundee Sustainable Technologies Inc. (DST) offers proprietary metallurgical processes for the treatment of material from the mining industry. DST processes enable the extraction of precious metals and for the removal and stabilization of contaminants, such as arsenic, from ores and concentrates. DST provides environmentally-friendly, viable and efficient processes, capable of handling complex and refractory ores which cannot be processed with conventional approaches due to metallurgical issues or environmental considerations. Several mining jurisdictions around the world have banned or restricted the use of cyanide. DST has developed a closed loop chlorination process as an alternative to the conventional cyanidation process for the extraction of precious metals from minerals. The tailings from the process are inert from toxic substances such as cyanide and organic compounds, are sulphide depleted which means they do not generate acid, and thus, meet and/or exceed environmental norms. The process has demonstrated excellent gold recoveries within a fraction of the time needed for cyanidation to obtain similar results. Moreover, the closed loop process does not generate any liquid effluent and does not consume much water: it only requires a water make-up to compensate for moisture leaving with the tailings and by-products, and seawater may be used. The improved environmental footprint of the DST process has been certified by the Environment Technology Validation program (ETV) which provides an independent evaluation of the performance claims of innovative technologies."

Jan 1, 2017

By J. A. Finch, R. R. Cunningham

The amount of foam volume generated in relation to the gas flowrate has long been used to define the foaminess of a solution and to characterize surfactants. The vessel geometry and gas flowrate range can affect the foam volume results. A fixed area column was tested alongside a variable area conical vessel with two surfactants. It was found that the fixed area vessel will cause foam volume to expand or contract which masks the effect of the surfactant. The conical vessel showed two regimes of foam volume production dependant on gas flowrate. The low gas flowrate regime revealed the physiochemical nature of the surfactant while a high gas flowrate revealed kinematic properties. Foaming properties of a surfactant is best determined with a variable area vessel at low gas flowrate.

Jan 1, 2009

By E. C. Morton

The Western Australian School of Mines (WASM) has developed a facility for the static testing of large scale ground support elements. The samples are loaded using a mechanical screw feed jack. Instruments measure the displacement and the load being applied. Methods have been developed for testing of mesh, shotcrete and membranes. Mesh samples are restrained on all sides and loaded centrally. A new large scale punch test method has been developed to evaluate shotcrete and membranes. These products are sprayed on to a sandstone substrate containing a centrally located isolated disc. The sprayed product is loaded by displacing the disk. The different test methods are described in detail. The test program involved two types of mesh, several shotcrete mix designs with different curing times and one membrane product. The force-displacement responses are used to directly compare the products. The implications for implementation of the different ground support products are discussed.

May 1, 2009

By Jean-Louis Robert

Field work inaugurated in 1962 in the townships of Lemieux and Lesseps, in the Gaspe Peninsula of Quebec, has permitted the author to delineate the lithologic units of the area, to elucidate a few stratigraphic problems and to outline several zones of alteration. Certain features of these zones and the numerous mineralized showings in the area merit the attention of prospectors and exploration companies.

Jan 1, 1966

By Z. Y. Ma, H. Y. Yang

The process of microwave-ultrasound assisted leaching of valuable metals from copper anode slime was proposed in this paper. Design of experiments has been used to study the effect of the main leaching parameters, such as microwave power, ultrasound power and reaction time. The central composite design (CCD) was used to predict the maximum leaching efficiency of copper, tellurium and selenium. The experimental data obtained were fitted to a second-order polynomial equation, and they also were analyzed by analysis of variance (ANOVA). The 3-D response surface plots and the contour plots were applied to determine the optimal conditions. The optimum conditions of microwave-ultrasound assisted leaching process were: microwave power 834W, ultrasonic power 638W and reaction time 403s. Under these conditions, the experimental leaching efficiency of copper, tellurium and selenium were 98.88±0.56% 98.96±0.78% and 98.57±0.67%, respectively, which agreed well with the predicted values.

Jan 1, 2014