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By Francis Gray

Mr. F. W. Gray: It is not my intention to read my paper as it is too long, so I will touch only on the high lights. The Sydney field is the most favourable example of undersea coal mining that exists, and I have not been able to find anything like it elsewhere. The nearest approach to it is a field in England where the Whitehaven collieries are operating, but it has a lot of faults. The net result of these faults so far met with in the seaward advance of the workings has been to increase, by something over 100 feet, the gain in depth of cover, in a distance of approximately three and three-quarter miles. In the Sydney field there are no faults of any consequence. On the east side, the English measures rise. In Australia the sea bottom fell and the cover became too light. On Vancouver Island the coal ran out, and in Japan the seams are steep and contorted. The Chilian fields resemble our own to some extent. An inundation of two collieries took place there some time ago, due, it is said, to the rise workings being allowed to approach the sea bottom too closely in the vicinity of a fault. The Cape Breton undersea field has been proved over a frontage of about thirty miles and has been attacked and penetrated for a considerable distance along that front. We have passed the prospecting stage and now generally use developed land areas as points of attack to win the undersea coal. Of our mining under the sea, it can be said that, with the exception of No. 1-B and Princess colliery, Sydney Mines, no real attempt has been made to win the undersea coal.

Jan 1, 1927

By Warren A. Sheaffer

THE chief uses for copper are as a conductor of electricity and as the chief component in brasses and bronzes. For such uses, the copper must be of very high purity. H the impurities are zinc, iron, lead, arsenic, or antimony, they can be removed to a great extent by fire-refining. H, however, gold, silver, nickel, or cobalt are present, electrolytic refining is necessary. Electrolytic refining must be preceded by fire-refining and hence all impure copper must be fire-refined. The electrolytic refining of copper is most efficiently carried on when the impurities in the anodes are at a minimum. Some of the impurities tend to deposit with the copper at the cathode, while others remain in solution, decreasing the conductivity of the electrolyte and thus increasing the voltage necessary for refining. Since these dissolved impurities must be removed by continuous purifications, the amount of impurity in the anode copper should be reduced by furnace refining to some predetermined limit. Anode furnace operation aims to reduce these impurities to a minimum beyond which the cost of further furnace refining would exceed that of removing the remaining small amounts of impurities from the electrolyte. The anodes should have a fine-grain internal structure because any pieces of metal becoming detached from the anode during the electrolytic refining are inconvenient to remove from the cells and may cause short-circuits. Impurities tend to disrupt such a structure and thus form zones of weakness during corrosion. When the impurities are reduced to a satisfactory mini-mum, the anode, due to having a fine-grain structure, will corrode uniformly over the entire surface area exposed to the electrolyte. Oxides of the impurities may be volatile, in which case they pass off as flue gases, or they may form viscous slags having a lower specific gravity than molten copper, thus permitting their removal by skimming. Some impurities can be oxidized by introducing air into the bath. Due to the large solubility of oxygen in molten copper, oxygen is distributed uniformly throughout the bath and thus comes into intimate contact with all impurities. The oxides which are insoluble in molten. copper are removed either as flue gases or as slag.

Jan 1, 1942

By G. Harper

"AbstractThe Suetut. Copper deposit, 230 miles northwest of Prince George, B.C., was discovered in August of 1971. Subsequent exploration has included 56,417 feet of surface diamond drilling in 139 holes. The deposit occur in gently dipping volcanic rocks of the Upper Triassic Takla Group, which out crops as rugged mountains.The general Mesozoic sequence comprises some 20,000 feet of green and red basaltic to andesitic rocks. The Lower Formation is characterized by subaqueous basalt, andesite and augite porphyry flows with interbedded breccias. They were rapidly deposited in tectonic depressions of limited extent and steep gradients. Facies changes are abundant. The Middle Formation. consists of volcaniclastic rocks made up of fragments from the underlying formation. Two cycles are discernible , both with basal turbiditic, tuffaceous sandstone and shale units overlain by massive, volcanic conglomerates exhibiting graded and cross bedding. A broader, shallower-water basin is indicated. The top of the uppermost unit was subaerially deposited. The Upper Formation is a variable sequence of volcanic sedimentary rocks. Detritus was supplied from a wide source area and included multiple reworked fragments of the lower formations and material from other rock groups known in the region. Zeolite facies metamorphism is recognized throughout: the entire sequence. Epidote is particularly abundant in the Middle Formation, demonstrating the results of metasomatism.The mineralized zone is approximately concordant with the strata over 100-200 feet of the Middle Formation succession . It lies just below the zone of transition from subaqueous to subaerial deposition in the top unit. Hematite, chalcocite, pyrite, bornite, chalcopyrite and native copper are disseminated throughout all sizes of lithic fragments and matrix. Concentration into the specific zone is believed to be due to upward leaching of copper during lowgrade metamorphic and metasomatic reaction. Precipitation occurred in the zone of hydration characterized by prehnite-pumpellyite below the oxidized subaerial rocks."

Jan 1, 1977

By V. G. Papangelakis, G. A. Moldoveanu

"Rare earths adsorbed on clay minerals are easily recovered via ion exchange during leaching with inorganic monovalent salt solutions. The leaching efficiency of various salts at 0.5M and 25°C was investigated as a function of cation type and salt system (sulphates vs. chlorides). (NH4)2SO4 was identified as the lixiviant of choice and a procedure was established to investigate the influence of lixiviant concentration, temperature, pH and agitation on desorption kinetics and REE extraction levels. It was determined that the kinetics were fast and the optimum leaching conditions (for >80% total REE extraction) required pH below 5 and moderate temperatures (<50°C). INTRODUCTIONRare earth elements (REE) are at the core of numerous advanced applications due to their various uses in high strength permanent magnets, lasers, automotive catalytic converters, fiber optics/superconductors, and electronic devices (as phosphors in TVs and display screens for computers and cell phones). Because of the ongoing development of new technologies, there is an increased demand for REE in the international market, with emphasis on identifying new resources to insure an adequate supply for present and future use. World production of rare earths is dominated by China, the United States and Australia; however, in terms of resources, China dominates the world potential with reserves estimated to be over 90% of the total (Chen, 2011).The main commercially significant REE sources, as reviewed by O’Driscoll (1991) are bastnasite (carbonate) and monazite (phosphate) minerals, containing up to 70% wt. rare earth oxides (REO). In spite of being high grade, these ores are associated with elevated recovery costs due to difficulty in mining, separation and beneficiation. Moreover, aggressive conditions are required to solubilize the REE from the mineral, such as leaching with hot, concentrated acids or baking in 70% NaOH (Gupta & Krishnamurti, 2005)."

Jan 1, 2012

By D. Campbell Mackenzie

THIS paper is submitted primarily to put on record the results of a number of experiments carried out at the Wingdam mine of Consolidated Gold Alluvials of B.C., Ltd., with the object of establishing a reliable method of concentration of &apos;wash&apos; and a maximum recovery of gold from the concentrate. It will be generally admitted that, during the last two decades, a tremendous amount of research work has been carried out, both by private companies and Government departments, with a view to improving the technique of the recovery of gold .from quartz veins or lodes. So thorough have been these investigations that milling practice at a modern quartz gold mine is almost an exact science, carried out with meticulous accuracy. In placer mining, on the other hand, very little departure from old traditional methods can be noted, with the exception perhaps of the more modern gold dredges. This may be due to the fact that the concentration of placer gravels, up to a certain point, is comparatively easy. Only a simple equipment of sluice box and riffies seems necessary where the gold is coarse and the gravel free from clay. In the early days of placer mining, when claims were rich and fairly 5hallow, nobody worried very much about fine gold; and, if clay was present, an enlarged dump box was constructed in which the gravel was subjected to a rather desultory puddling. That large quantities of gold are lost in normal placer practice is generally admitted. Some 26 years ago, I had inspectorial charge of many bucket dredges on the Ovens river, in Australia. Occasionally it was necessary for a dredge to work through its own tailing to reach a new section, and almost without exception enough gold was recovered from these tailings to defray the total cost of moving the dredge. Since those days, the technique of gold recovery in dredging has been considerably improved and it is still receiving close attention. Outside of dredge mining, most placer operations, deep or otherwise, are as they were-notorious gold losers, paying little attention to the recovery of fine gold and taking an absurd amount of time over each clean-up. In the Cariboo district of British Columbia, the alluvial gold is usual y associated with varying quantities of black sand (magnetic) and grey sand (non-magnetic); and it can be taken as axiomatic that, if you save all the black sand and grey sand, you save practically all the gold. It is on this hypothesis that we have carried out our research work and brought our recovery system up to its present highly satisfactory standard.

Jan 1, 1937

By M. Lahtinen

Traditionally, there have been three main methods for iron removal in the hydrometallurgical production of zinc. These methods are atmospheric precipitation of jarosite or goethite and pressurised precipitation of hematite. Jarosite precipitation is without doubt the leading and the most commonly used technology for iron removal. However, jarosite precipitation has some drawbacks, such as a low iron content (and, thus, high residue volume), high moisture content after filtration and often a high zinc content. These features make any environmentally acceptable way of using or disposing of jarosite more expensive, as compared to hematite and goethite. The importance of environmental regulations has grown in the zinc industry during the last decade, which will have an increasing effect on new investments. Hematite has several advantages over jarosite, such as a high iron content, low moisture and low zinc content. An important advantage of hematite is that it is suited for further use in the cement industry. However, until now the need for autoclave equipment has limited the spread and implementation of hematite precipitation in the zinc industry. Outokumpu Technology Oy has recently developed an alternative method for iron removal, which is the atmospheric precipitation of hematite. A patented method for precipitating hematite at atmospheric pressure is presented and compared with conventional methods for iron removal. The process conditions, the quality of the hematite precipitate and the environmental aspects are also discussed.

Jan 1, 2006

By Graeme G. Strathdee

"IntroductionThis paper presents an overview of the industry status, describes current potash industry practices at three mills, and summarizes developments that have taken place since the previous review by Banks (1985).The commodity potash is produced in both New Brunswick and Saskatchewan from the evaporite ore sylvinite. This ore is a mixture of co-crystallized halite, NaCl, and sylvite, KCl, and a minor assortment of silica, carbonate, sulphate, and clay minerals. Carnallite, KMgCl3.6H20, is also dispersed throughout the bedded deposits and can affect the recovery of sylvite for fertilizer and industrial uses.Canada continues to be a principal source of supply of agricultural and industrial potash products. Figure 1 shows the sector performance between 1989 and 1997 in the context of the world supply and demand situation as reported by Prud'homme (1997) of Natural Resources Canada.Potash industry output is traditionally measured as the quantity of potassium nutrient and reported as tonnes ofK20. Mineralogically, the principal form of potash produced in Canada is sylvite, KCl, and 1 nutrient tonne K20 corresponds to approximately 1.64 tonnes of sylvite of agricultural grade, about 95% KCI. In 1997, the Canadian industry milling capacity was 13.4 million metric tons (Mt) ofK20 (22 Mt KCl) while the actual production was 9.0 Mt K20 (14.8 Mt KCl). Worldwide milling capacity in 1997 was 35.9 Mt K20 (58.8 Mt KCl) and global consumption was 25.3 Mt K20 (41.6 Mt KCl). Canadian producers can deliver about 35% of the global demand for potash commodities"

Jan 1, 2000

By A. M. Esteves

This paper offers an overview of local content policies and practice in the mining sector. Specifically, the paper aims to answer the question of how national and regional governments, industry and civil society can work together to seek an optimal outcome while pursuing their diverse objectives. The paper begins by defining local content and its scope at the subnational level. Specific recommendations for the design of local content policies to mitigate social, economic and governance risks are developed. The document then offers some recommendations regarding the role of partners in design, implementation, monitoring, and enforcement of local content policies.

Aug 1, 2013

By D. Auerswald, M. Kotze, V. Yahorava, T. Udayar

Uranium can be recovered from lower grade uranium ores (<800 mg/kg U3O8), leach residues, and waste dumps cost-effectively via resin-in-pulp (RIP). Using this technology, no solid/liquid separation or washing of the leach residues are required. Furthermore, the uranium recovery can be higher than with conventional methods. RIP technologies have, however, been perceived negatively due to concerns around potential resin fouling and losses. This paper highlights the advancements made in RIP and discusses a number of potential applications where the technology could deliver economic and consequential environmental benefits by reducing the uranium levels in the waste.

Jan 1, 2014

The SART (sulfidisation, acidification, recycle, and thickening) process is an effective way to separate copper and cyanide from each other in the waste stream of gold processing plants using cyanidation. Factorial experimentation has been conducted to create models of copper recovery, cyanide recovery, acid addition, and oxidation I reduction potential during SART. Economic analysis of the resultant models showed that SART is best operated with a sulfide to copper molar ratio of around 0.56, a pH of 4, and a minimised cyanide to copper molar ratio. The experiments also showed that thickening time may have drastic impacts on SART performance.

Jan 1, 2011

By A. W. JR. Whitaker

Introduction Within the last quarter of a century the Lake St. John-Saguenay valley has been converted from a quiet agricultural district to one of the important industrial centres in the Dominion. First there was the expansion -of the pulp and paper industry, and then, starting a little over ten years, ago, the development, in large .blocks, of the enormous hydro-electric power resources of the Saguenay river. Coincident with this power development, the world aluminum industry was rapidly expanding and looking for a new source of cheap power. This was found in the Saguenay valley-and so, in 1925, Arvida was established by the Aluminum Company of Canada as a location for one of the largest aluminum plants in the world. Arvida, an incorporated city comprising an area of some ten square miles, is ideally located on a more or less level plateau about 350 feet above the Saguenay river. Seldom has industry stepped boldly forth and carved out of Nature a community with full city status. The process usually goes through the steps of camp, village, town, and city, involving improper planning or lack of planning; all of which has been avoided at Arvida by starting out in the right way. While this community has only a population of approximately 2,000 at the present time, it is carefully planned for a population many times this figure. Streets, city parks, business and residential sections, have been definitely planned, and, with a City government, proper ordinances were passed at the beginning to ensure the building and maintenance of a model industrial community. As the crow flies, Arvida is about 35 miles due east of lake St. John, and 0 miles west of the St. Lawrence river at Tadoussac. From a shipping standpoint, it is well served by the Canadian National railways, with direct lines to Quebec and Montreal, and by ocean shipping facilities at Port Alfred, which is about 15 miles to the east on the Saguenay river and is served by the Roberval & Saguenay railway. The latter has interchange connections with the Canadian National at Arivda, and also operates a branch line into the city of Chicoutimi.

Jan 1, 1933

By A. A. McCloskey

APPROXIMA TEL Y 95 percent of Waite-Amulet&apos;s Lower A orebody will be mined by diamond-drill stoping. This method of stoping was developed, and has been successfully applied, at the Noranda mine in recent years(1) and is now used in several base-metal and gold mines in north-western Quebec and in other parts of Canada, South Africa, and Australia. The purpose of this paper is to deal with the features of the Lower A ore-body which led&apos; to the adoption of this method of stoping, and in addition to give a general description of stope layout, stope development, main haulage development, chutes and grizzlies, diamond drilling for stope blasting, diamond drilling and equipment, primary blasting, secondary blasting, haulage and loading, ore pockets, pumping and drainage,. and shafts at Waite Amulet. Figure 1 is an isometric projection of the orebody, illustrating the mining system. The factors that led to the adoption of diamond-drill stoping of Lower A orebody are as follows: (1) Safety.0 (2) Size and shape of the orebody, and depth of the orebody below surface. (3) Strength of the hanging-wall, footwall, and sulphide ore. (4) Continuous ring-drilling from sub-level drifts, with no delay for blasting. (5) Large-tonnage blasts at the end of Saturday afternoon shift, after ali men are out of the mine. (6) Sub-levels may be retreated from top to bottom simultaneously, or lower sub-levels may be retreated first without any change in the ring-drilling la yout. (7) Large stopes up to 100 feet wide can be mined, leaving substantial pillars up to 60 feet in width, which may be partially recovered by âiamond~drill stoping or by other stoping methods. (8) A large tonnage may be drilled-off in advance of blasting, but only a supply of unoxidized ore for flotation treatment is blasted. (9) Better ventilation during working shifts. (10) Gravity flow of all broken ore to grizzlies located in the footwall of the orebody. (11) Electric blasting by a crew of two men.

Jan 1, 1941

By Anoop Sattineni

Over the past decade the use of BIM in the AEC industry has grown several fold and with it the number of standards available for implementing BIM. The ?National BIM Standard? by buildSmart Alliance, the ?Contractor Guide to BIM? by the Associated General Contractors of America, the ?BIM Project Execution Planning Guide and Templates? from Penn State University, the ?BIM Roadmap? by the US Army Corps of Engineers are some of the several BIM guidelines that are currently available to the AEC industry practitioners. Some of these guidelines are as comprehensive as defining BIM and the associated taxonomy while others are meant to be used on an individual project basis. From a contractor?s perspective one of the key benefits of using BIM is for the purpose of collision detection and coordination. This research has found that currently available guidelines do not address these issues adequately. For instance, the currently available guidelines do not allow the subcontractor to quickly communicate issues such as naming conventions and color schemes within the model, to the general contractor. Consequently general contractors and sub-contractors find themselves making changes to their BIM deliverables based on each other?s abilities and levels of adoption, apart from reason?s stemming from use of different software platforms. This paper describes how a group of contractors and subcontractors from Atlanta and Birmingham in the United States came together to create and adopt a ?Coordination Guidelines for Virtual Design and Construction?. These guidelines were specifically created with the purpose of streamlining the construction coordination process using BIM. This paper describes how the guidelines created differ from other guidelines currently available in the industry.

Aug 1, 2013

By A. R. Chambers

At the 1924 Annual Meeting of the Institute, held in Toronto, the writer presented some notes on the occurrence of salt at Malagash, Nova Scotia, together with a few remarks on the uses of salt. The development of these salt mines has attracted considerable attention to the district, and it may be of interest at this time to call attention to some of the newer uses of salt, and to give a brief account of the genesis of the Maritime salines, As it is not proposed to treat the subject in technical detail, and the paper is written in a lighter vein than is usual in contributions to your Transactions, you will please overlook any variations from a strictly technical method of presentation. The world&apos;s supply of salt is obtained in three principal ways: (1) By flooding shallow areas, or pans, with sea water, allowing the water to evaporate naturally by the heat of the sun&apos;s rays, and collecting the residue of solid salt. This method is employed, for example, at Turks Island, B.W.I. (2) By mining the rock salt in its natural state, and preparing it for market by a grinding process. This is the method adopted at Malagash, which is the only place in Canada where salt is actually mined. (3) By drilling a hole into an underground salt deposit, forcing fresh water clown the hole, and, after it has become saturated with salt, pumping the brine to the surface and recovering the salt by evaporation. This is the method pursued by the Canadian Salt Company, the Dominion Salt Company, and other producers in Ontario.

Jan 1, 1929

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 A. Pawelczyk, D. Hreniak, E. Zych, W. Strek, K. Grabas, A. Ostrowski

"Nowadays recycling became an important rare earth elements (REE) source, which allows to reduce their demand for extraction from natural deposits. At present, the used fluorescent lamps and old type TV or computer monitors kinescopes are selectively collected and undergo processing in the system of recycling. It has been estimated, that utilization of such waste would be sufficient to cover the REE demand for the next 5-8 years. In the developed process, the luminophores were separated from the electronic and electronic waste materials, and processed by hydrometallurgical methods to obtain concentrated REE in form of oxides. INTRODUCTIONInternational Union of Pure and Applied Chemistry (IUPAC) defines the rare earths as a set of seventeen chemical elements, specifically the fifteen lanthanides plus scandium and yttrium. They are considered the most important indicators of the developed technologies and techniques. Rare earths are used, amongst others, for the production of magnetic and superconducting materials, ceramics, lighting, catalytic converters, advanced electronics and alloys. The demand for RE continually increases, similarly to many other primary raw materials. Globalization, the growing demand for limited resources of raw materials, the policy of the countries controlling the raw material market and the economic crisis became a spur for new programs of socio-economic development of the European Union (EU), with particular regard to EU safety for commodities in intermediary as well as long-term horizons (COM 2008), COM 2011).EU countries import most of metallic and chemical raw materials important for their economy. In 2008 a detailed program named Raw Material Initiative was announced. The increase in demand for most raw materials having special importance for the development of technology, and access to of raw materials security of supply affect the future economies of the UE member states and other developed countries."

Jan 1, 2012

By K. H. Poulsen, C. J. . Hodgson

Synvolcanic, layered gabbro-anorthosite sills at Rainy Lake, Northwestern Ontario, reflect a combination of igneous processes including fractional crystallization, wall rock assimilation and possibly liquid immiscibility. Chalcopyrite-pyrrhotite mineralization at the base of the Grassy Portage intrusion accumulated by crystallization of a sulphide liquid during cooling. Upward enrichment of Fe and Ti in this intrusion and also in the Bad Vermilion Lake anorthosite complex culminated with the crystallization of lenses of disseminated to massive magnetite+ apatite+ ilmenite+ rutile. Regional low to medium grade metamorphism and accompanying deformation resulted in recrystallization and local remobilization of ore minerals.

Jan 1, 1984

By Imre Gombköto, Barnabás Csoke

"Raw material management means not only mining and processing of primary raw materials like ores, but means also collecting and processing secondary sources of raw materials. Recycling is one of the most developing field of raw material management in Europe, and its solutions are derived from mineral processing roots and principals. Complexity and challenges of the field of recycling results innovative solutions of material processing- Since European Union identified 20 raw materials as critical (CRM) due to lack of primary sources within the border of the EU, recycling become more recognised as source of different raw materials. WEEE is the waste streams contains many of the critical elements and along them at least 15 different species of plastics of which recycling is delayed by a lack of effective separation technique. Most paper deals with separation methods based on different specific gravity, triboelectric charge or surface properties of plastic species. Plastics however have differences of thermal properties and thermoplastics, duroplasts and elastomers can be recognised. The experiments described in the paper aimed to determine thermo adhesive behaviour of plastic species often identified in WEEE streams for separation purposes. According to the results, some plastic types as PS, PP. PC or PVC and PET pairs are possible to easily separate from each other, however different additives are changing thermo adhesive properties of most of the plastics that makes industrial process difficult to develop. Along thermo adhesive behaviour, combination of physical interaction can be used to enhance separation selectivity.INTRODUCTIONPlastics has a relatively long term of history as a light, multi-functional material in construction, packaging, automotive industry and electric and electronic products. There are a numerous types of plastic species can be used for various applications therefore they amount are growing from year to year. This quantity however become part of the waste stream and while metal recycling has been done for decades due to its economic value - cheap plastic parts are less desirable as secondary products. In 2013 an annual 5% of plastic production growth has been estimated with a base data of 265 million tonnes at 2010 (Guiqing & Zhenming, 2013). Since landfill requirements are increasing while—especially in Europe where actual regulations are trying to deflect waste from landfills - landfill capacities are decreasing, costs are become more and more expensive, Applications like energy production based on plastics as a fuel or recycling are some of the options can be applied. Direct incineration of plastics are applied at many plants - in most cases where waste consist of dangerous substances are incinerated because plastics high calorific value helps correct average mixture composition enable operators reaching high enough temperature for combined power and heat generation while most of substances—like PAH, PCB or dioxins—are destroyed. Another path is using low temperature reductive cracking due to pyrolysis process, however the chance having higher concentrate of carcinogen substances in the products are higher since it applies around 400°C during the process."

Jan 1, 2016

By J. E. Nesset, W. Zhang, J. A. Finch

Frother influences water recovery through control of bubble size and a chemical effect. De-coupling the two is necessary to establish the extent of the chemistry effect. A setup is described to give steady state water overflow rate (Jwo) along with measurements of bubble size into and on top of the froth. Arguing neither bubble size correlates directly with water overflow, a frother mass balance is solved to estimate the bubble surface area flux in the overflow (Sb0 ). The solution required measurement of frother concentration using TOC analysis and frother adsorption density using surface tension data. The relationship between Jwo and Sbo reveals the frother chemistry effect, quantified for discussion purposes by an equivalent water layer thickness.

Jan 1, 2009

By Edouard Asselin, Tasawar Javed

This study was conducted as a part of ongoing work to characterize sulphide concentrate leach residues generated under CESL (Cominco Engineering Services Limited) and Vale pilot and demonstration plant medium temperature (150 °C) process conditions. Three different samples were analyzed. Derivative samples were prepared by extracting gypsum, sulphur and amorphous/poorly crystalline iron oxyhydroxide phases from the leach residues. Thermal behavior of the samples was studied by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) in the temperature range 25 to 800 °C in both air and nitrogen atmospheres, with XRD analyses both before and after heating. Thermal transformation temperatures for different iron oxides/oxyhydroxides present in hydrometallurgical leach residues vary over a wide range which suggests the variable crystallinity of the phases. Raman spectroscopic analysis was carried out to help identify the type of iron phases in the residues. Furthermore, hydroxylamine hydrochloride (HaHC) and oxalate extractions were used to compare the fractionation of the amorphous/poorly crystalline iron phases in the residues. Given the compositions of the residues, any thermal events in the temperature range of 200 °C to 480 °C were attributed to amorphous/poorly crystalline iron phases.

Jan 1, 2014