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By K. Chomyn, R. Veenstra, P. Zangeneh, Hatch Ltd., C. Van der Woude, H. Ghorbani

"The furnace is the heart of smelting operations, and therefore the performance, reliability, and campaign life of the furnace are critical considerations. Furnace refractory is exposed to high temperatures and other harsh operating conditions causing brick erosion, crushing, and cracking, typically limiting the furnace campaign life and requiring costly furnace shut-downs for refractory re-lining. Despite extensive study, the in-service thermal / mechanical stresses in these complex refractory systems are not generally well understood. Hatch has developed a thermal-mechanical finite element analysis (FEA) based furnace refractory modeling approach that allows for the quantification of refractory movements, load distribution, and thermal / mechanical stresses.Due to the complexity of the refractory system, a range of models are used to identify and assess damage mechanisms and design improvements, including: 2D models, to capture expansion and movement of individual bricks, changes to load paths, and thermal stresses; and 3D models, to include the effect of differential expansion between bricks in each course, and assess overall load distributions. The 2D and 3D analyses include the effect of nonlinear temperature-dependent properties, thermal expansion, movement of individual bricks with frictional contacts (i.e., gaps can open, bricks can slide), and brick tensile or compressive failure. Both as-built and damaged conditions can be investigated (e.g., after bath zone brick erosion), for circular and rectangular furnaces. 3D models also include papering and brick joint & interface action.Analyses using these models have shown the importance of thermal stresses, papering, and geometry / arrangement of individual bricks. Results have been used to identify and assess damage mechanisms, showing good alignment with furnace autopsy observations. By using this FEA-based approach to quantify the refractory design, the risk of damage can be significantly reduced, low-cost design changes can be identified, and the furnace campaign life can be extended.INTRODUCTIONThe furnace is the heart of smelting operations and therefore the performance, reliability, and campaign life of the furnace are critical to the success of the smelting operation. Furnaces are inherently exposed to high temperatures, often in excess of 1600°C (Holappa, 2004), and furnace operating power has progressively increased over time (Voermann, Gerritsen, Candy, Stober, & Matyas, 2004). The refractory system must withstand high temperature, high heat flux, and other harsh operating conditions. These conditions are particularly significant for the furnace hearth, and can lead to damage including brick erosion due to molten material flows, crushing due to thermal expansion loads, and cracking due to severe thermal gradients within the bricks. Refractory damage typically limits the furnace campaign life, requiring costly furnace shut-downs for refractory re-lining (repair or replacement). In some cases the refractory may lose integrity causing damage to nearby equipment and harm to personnel."

Jan 1, 2016

By E. L. Horner

"Srnoky River Coal is capable ofprocessing 3 million tonnes per year ofrun-of-mine coal at the Smoky River Coal preparation facilities to produce 2.1 million tonnes of high quality, low volatile coking coal for export markets. Multi-seam surface and underground mining operations are scheduled to maintain raw coal feed to the plant. Two beneficiating circuits wash the coal. A heavy medium cyclone circuit cleans the plus 0.5 mm coal and a froth flotation circuit cleans the minus 0.5 mm coal. Clean coal is thermally dried, loaded into unit trains, treated for dust suppression, and transported to west coast port facilitiesf or export. Plant by-products are used as thermal fuel Jn an adjacent power station. Quality control procedures ensure efficient resource recovery for a yield of uniform specification product, at a 7% ash level. Introduction Smoky River Coal operates surface and underground mines in the Smoky River coalfield. Approximately 3 million tonnes per year (mt/ a) of run-of-mine (ROM) coal can be processed at the coal preparation plant to provide 2.1 mt/ a of clean, high quality, low volatile bituminous coking coal. Coal is processed by heavy media and froth flotation cleaning circuits and is thermally dried.Raw Coal Characteristics The characteristics of the ROM coal, both in terms of quality and size consistency, vary with intrinsic seam qualities and mining methods employed. The two seams mined (No. 4 and No. 10) show distinctly different washability characteristics. Seam No. 4 contains relatively few middlings and can be readily cleaned by dense-medium cyclones and froth flotation to give a clean coal at specification ash content. Seam No. JO is more difficult to wash, and the ash content of the clean coal is higher than No. 4 seam at the same operating conditions. However, when the upper I m is excluded from the plant feed, the remaining lower section has washability characteristics similar to No. 4 seam. Coal mined by underground means sometimes contains caprock and consequently tends to be dirtier than similar coal mined by surface means."

Jan 1, 1985

By N. Molaei, E. R. Bobicki

The continued demand for mineral products, coupled with the depletion of high-grade ore resources, has led to the mining of lower grade ores, which often require fine grinding to achieve mineral liberation. Regrinding of low-grade ores results in the production of fine gangue mineral solids and produces vast quantities of fluid fine tailings which are difficult to separate from water, particularly if they are composed of clay minerals. Organic synthetic polymers and inorganic salts have been widely applied in flocculation of colloidal suspensions in the treatment of mining tailings. However, there are growing concerns regarding their impact on the environment and human health. Recently, extracellular biopolymer flocculants or bioflocculants have attracted much attention as alternative reagents. In this study, much effort has been devoted to considering the effectiveness of protein and polysaccharide-based biopolymers for the dewatering of clay slurries. The interaction between kaolinite and illite clays and biopolymers was investigated via settling tests at pH 7 and 10. Zeta potential measurements were also conducted as a complementary technique. Results showed that protamine and lysozyme protein- based biopolymers were generally the more effective bioflocculants. Pectin, a polysaccharide-based biopolymer, showed a dispersing effect and has the potential to be used as a dispersant and/or depressant for clay minerals in froth flotation. INTRODUCTION With the depletion of high-grade ore resources, the need for mining of low-grade ores has increased over the past few decades (Bourgès-Gastaud, Stoltz, Dolez, Blond, & Touze-Foltz, 2014; Chen, Walshe, Fru, Ciborowski, & Weisener, 2013; C. Wang, Harbottle, Liu, & Xu, 2014). Low-grade ores often require fine grinding and contain clay minerals, leading to the generation of fluid fine tailings (FFT). It is a challenging process to separate suspended clay particles from water (Craciun, Manaila, & Stelescu, 2013; Dompierre, Lindsay, Cruz-Hernández, & Halferdahl, 2016; Kasperski & Mikula, 2011; Mercier et al., 2012). Clay minerals form stable dispersions in water due to their anisotropic nature, non-spherical morphology and colloidal size (Lagaly & Ziesmer, 2003; Olphen, 1977). The difficulty in separating clay minerals from water has led to the accumulation of vast quantities of FFT in oil sands, phosphate, copper and nickel operations, representing a huge liability for mining companies (Chen et al., 2013; Mercier et al., 2012)

Jan 1, 2019

By W. L. Brown

"The properties of Base Metal Mining Corporation are in Yoho Park about 2 1/2 miles northeast of Field; British Columbia; on the main line of the Canadian Pacific railway. There are actually two mines; the Monarch on mount Stephen and the Kicking Horse on mount Field; separated by the steep valley of Kicking Horse river. The outcrops of the orebodies range from 4; 900 feet to 5; 300 feet above sea-level. The concentrator is situated below the Monarch mine and is connected to the main portal by an aerial tramway. The ore from the Kicking Horse mine is conveyed by aerial tramway to a storage bin on the main highway and is then trucked to the concentrator.During the construction of the Canadian Pacific railway through Kicking Horse valley, galena float was found at the base of mount Stephen. The East Monarch outcrop was staked in 1894. The outcrop of the West Monarch ore body on the cliff face of mount Stephen was not discovered until 1916. The Kicking Horse orebodies on mount Field were discovered a few years later. In 1912, a 75-ton concentrator was erected, which operated at intervals until 1924. During this period approximately 42,000 tons were mined and milled, largely from the East Monarch orebody. In 1928, the Base Metal Mining Corporation, Limited, was formed to take over the Monarch and Kicking Horse mines. A 300-ton differential flotation concentrator was erected and production started in the autumn of 1929. In a very short time, however, the low price of metals forced the mill to shut down until August 1933. From 1929 to 1935, when the mill again ceased operation, a total of 256,500 dry tons of ore, averaging 1.59 oz. silver per ton, 9.7 per cent lead, and 12.6 per cent zinc, was mined and milled, largely from the West Monarch orebody. After a period of further underground development, the concentrator reopened in 1940 and is still in operation. From 1940 to the end of 1944, 354,363 tons of ore was milled, averaging 5.32 per cent lead and 10.47 per cent zinc."

Jan 1, 1954

By K. E. Waters, J. E. Nesset, F. Rosenblum, J. A. Finch, S. Moon

"Some materials when exposed to various conditions can exhibit a rise in temperature without requiring an external heat source. Generally referred to as pyrophoric or self-heating substances, they challenge the safety of materials handling, storage and transportation. Reliably assessing the self-heating potential of materials is thus essential. Over the years a number of test protocols have been developed. A widely accepted method is that recommended by the United Nations to certify the safety of shipping pyrophoric goods. Our test work on sulphide materials has shown that the U.N. test can give false negatives if the sample oxidation history is not considered. Depending on the degree of oxidation (“weathering”), the same sulphide material can exhibit self-heating ranging from safe to hazardous. For concentrates, oxidation can occur during storage and transport making the sample weathering history an important consideration in the test work. To make the U.N. test, and other single-stage self-heating procedures, more reliable in assessing self-heating potential when testing sulphide materials, it is suggested that a weathering step be incorporated in the test protocol. This test work for two sulphide samples, an ore and a concentrate, demonstrates the impact of incorporating a weathering stage in the test protocol. INTRODUCTIONSelf-heating occurs when exothermic reactions produce heat faster than can be dissipated to the surroundings. Numerous substances self-heat, ranging from wood chips and powdered milk to coal and sulphide minerals (Beever & Crowhurst, 1989; Hudak, 2002). Mixtures of sulphide minerals, most notably those containing the iron sulphide pyrrhotite (Fe(1-x)S), commonly encountered in the extraction of base metals (e.g., copper, zinc, lead, and nickel), are particularly prone to self-heating (Rosenblum, Nesset, & Spira, 2001; Payant, Rosenblum, Nesset, & Finch, 2012). In the mining and subsequent processing stages, the minerals are progressively liberated and finely ground, then separated, usually by flotation, with the resulting concentrates stored and transported to smelters for metal extraction. At most of these stages the sulphides are exposed to both moisture and oxygen, conditions that promote partial sulphide oxidation and the formation of elemental sulphur. Studies have shown that pyrrhotite, in particular, readily oxidizes to form elemental sulphur (Bernier & Li, 2003; Belzile, Chen, Cai, & Li, 2004; Somot & Finch, 2010). The elemental sulphur becomes fuel for further self-heating as the temperature of the mineral mixture increases above 100 oC (Rosenblum & Spira, 1995; Somot & Finch, 2010). It is believed the propensity of pyrrhotite to self-heat is a result of its iron-deficient, and hence somewhat unstable structure. It is worth noting that pure metal sulphides (with the exception of pyrrhotite) do not exhibit appreciable self-heating. A mixture of minerals sufficiently different in their electrochemical rest potential is required to initiate self-heating at ambient temperatures (Payant et al., 2012)."

Jan 1, 2016

By T. I. . I. Sibbald, D. E. Jiricka

The Goldfields area on the north shore of Lake Athabasca , was active in the thirties and early fortie . In 1934, Tom Box discovered gold mineralization in quartz veins in pyritized 'granite' at the ite of what wa to become the Box Mine of the Consolidated Mining and Smelting Company of Canada Ltd . In the rush of activity that followed numerou other gold occurrences were found. the most significant of the e being the Athona and Frontier prospects which underwent underground development bur did not reach production. Probable reserve identified to date in the Box and Athona deposits amount to some 3.5 million ton grading an average 0.ITT oz gold/ton . Some 10 to 15 million tons of lower grade, po ible reserve are also reported at the Box. From 1939 to 1942, the mine produced, from underground , 64,066 ounces of gold from ore grading 0.0452 oz gold/ton at a cost of between $1.5 and $2.0 a ton. The Goldfield area is underlain by upracrustal rock intruded by mafic bodies and invaded by ·granite'. The upracru tal . thought to be of Lower Proterozoic age are characterized by a helf-type ucce ion metamorpho ed under lowermiddle amphibolire facie conditions into quartzites, quartz-mica chi ts. dolomitic marbles, diop idic calc-silicates and cordierite-anthophyllite-biotite schi t . Amphibolites of presumed igneou origin form concordant to subconcordant units up to a few ten of metre thick in the upracrustals and occur as le regular masses in the 'g ranite·. Compositionally they vary from gabbroic to granodioritic. with the more mafic varieties being most common. Granitic rocks exhibiting a variety of textural , structural and compositional characteristics underlie most of the area. Four main units are recognized: foliated (older) 'granite', 'leucogranite', feldspar augen 'granite· and pyritic mine 'granite', however, in geological mapping the e are somewhat arbitrarily differentiated due to transitional relationships and admixture of types. Although there is no unambiguous age data available for the e 'granite ' adjacent northshore 'granite' of geologically similar age yield Rb-Sr isochron dates around 2000 Ma. The area is characterized by two major deformation events of which the earliest gave rise to the dominant regional foliation and to rare minor and outcrop scale folds. This foliation which in general parallels compositional layering is folded into the major Goldfields syncline, whose axis plunges weakly to moderately outh. Related open minor folds have subvertical axial surfaces which are locally paralleled by a weakly defined schistosity. Most rock display a pronounced rodding fabric, coaxial with second fold axes and apparently the product of this deformation event. However, a note of caution is introduced into this interpretation, as the rodding fabric is also parallel to first fold axe .

Jan 1, 1986

By K. Thuro, S. Schneider, H. Kasling, P. Ellecosta

"One of the most important methods for material testing is the characterization of the hardness, which is defined as the resistance of a material to the penetration of another one. The methods according to Brinell, Vickers, Rockwell and Knoop are today the most common and standardized tests for metal. As they are developed for predominantly ductile materials like steel, they can’t easily be applied to rocks which react much more brittle under indentation. But just as steel, rock is composed of different minerals and has a specific microstructure. Its mechanical parameters are connected with the particular grains, their cohesion and interlocking, just like steel.The abrasivity of rocks and the accompanied wear of drilling tools today are mainly determined by simple and fast laboratory tests such as the Cerchar abrasivity test or the rubber wheel test. Such laboratory tests are good tribological tests, but there are limits. The Cerchar abrasivity test for example has weaknesses in extreme cases, that mean soft or very hard rock types. This leads to an underestimation of abrasivity, e.g. in poorly lithified sandstones or very hard, fine grained and extremely abrasive rocks. As mentioned, hardness characterizes, depending on the type of deformation, predominantly plastic (metal) or elastic properties (rubber). Rocks are in the range between these two extremes. Since the rock drilling process can be seen as a kind of penetration process on macroscopic and microscopic scales, we picked up the idea to characterize the interaction of rock materials and TBM-disc-cutters with hardness tests. In addition, this supports for a better understanding of the wear process on disc cutters. We used the hardnessdisparity concept after Cardu & Giraudi (2012) because wear can be understood as the interaction between the wear part and the material which causes the wear (tribological system). Several rock-forming minerals and some fine to coarse-grained monomineralic and polymineralic rocks were tested. In contrast to Cardu & Giraudi, we used in the first step of investigations the method after Vickers with loads up to 294.2 N (HV 30), depending on the estimated hardness to get bigger indentations and therefore as well information about the cohesion and interlocking of the minerals/grains. We also tested several associated disc cutters. First results show that with higher loads (HV 5 - 30) and at least 15 indentations, we get a structural hardness in fine-grained rock samples, which allows a good characterization of the elasticity and brittleness. Nevertheless, for the coarse-grained rock samples we need up to 40 indentations for a good characterization. Using this method, a prediction of disc cutter wear is feasible taking into account the hardness of the disc cutter steel. In this paper, we would like to present this approved method in material sciences to derive an additional parameter for the characterization of rock abrasivity and wear."

Jan 1, 2015

By Burden of Occupational Cancer in Canada Project Team, Demers P. A., Kim J., Arrandale V. H., Jardine K.

"In 2012 diesel engine exhaust (DEE) was classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and is one of the most common workplace carcinogens internationally. We estimate that approximately 2.4% of lung cancers (n=560) and a suspected 2.7% of bladder cancers (n=200) are attributable to occupational exposure to DEE annually in Canada. High levels of exposure to DEE in mining results in a disproportionate number of cancers in this sector (approximately 220 lung and 20 suspected bladder cancers annually). These could be prevented by reducing the number of workers exposed and level of exposure. KEYWORDS Bladder cancer, Diesel engine exhaust, Economic burden, Lung cancer, Mining, Occupational cancer, Prevention, Regulation INTRODUCTION Diesel engine exhaust is a complex mixture of gases and particulates containing known and suspected carcinogens such as benzene, polycyclic aromatic hydrocarbons (PAHs), and metals. Approximately 900,000 Canadians are exposed to diesel engine exhaust at work, making it the most prevalent occupational lung carcinogen in Canada (CAREX Canada). Diesel engine exhaust is recognized as one of the most common workplace carcinogens in the world, but its classification as a human carcinogen by the International Agency for Research on Cancer (IARC) was relatively recent. In 2012, after decades of mounting evidence, diesel engine exhaust was upgraded from a probable (IARC Group 2A) to a definite human carcinogen (IARC Group 1) (IARC, 2014). The IARC evaluation was based on strong evidence in humans for an increased risk of lung cancer, as well as strong evidence in animal studies. The key human evidence considered by IARC was from epidemiologic studies of workers in truck transportation, rail transportation, and mining industries, where the use of diesel engines is widespread. These studies provided strong sufficient evidence for an increased risk of lung cancer, as well as limited evidence for bladder cancer. The human studies used particulate matter, generally measured as elemental carbon (EC) or total carbon, as a surrogate for diesel engine exhaust to assess the risk associated with level of exposure. The animal studies reviewed by IARC showed sufficient evidence for cancer with exposure to whole diesel exhaust and the particulate matter fraction of diesel exhaust, but not for the gas phase components."

Jan 1, 2019

By L. Wolofsky

"The Candego property is in Boisbuisson and Christie Townships, Quebec, about 13 miles south of Marsoui, a village on the north coast of the Gaspe peninsula, 80 miles east of the railhead at Matane. It was the first producing mine in the peninsula. Production to October 1954, when operations were suspended, totalled 68,497 tons of ore, which yielded concentrates containing 8,706,535 lb. lead, 5,870,272 lb. zinc, 355,526 oz. silver, and about 1,000 oz. gold. The property was acquired by the present company in the summer of 1955.The mine has been developed by seven adits, driven into the west slope of the valley of the Marsoui River. The river here is at an elevation of about 1,600 feet, and is roughly 1,500 feet below the level of the adjacent upland. Adit elevations range from 1,760 to 2,330 feet. Five of them are in one vertical zone, on what was originally believed to be a single vein. Past production has come from Nos. l to 5; the chief present high-grade ore reserves are in No. 7.The author's observations were made in adits Nos. 3 to 6, in several of the old pits, in the surface trenches, and on drill core, at various times between December 1952 and September 1953. Much of the surrounding area has been mapped by Jones (I) and McGerrigle (2) for the Quebec Department of Mines. H. M. Kingsbury served as consulting geologist to the mining company for several years.General GeologyThe Candego veins occur in Lower ( ?) Ordovician sedimentary rocks which form a strip about 15 miles wide along the north coast of the Gaspé peninsula. The series includes limestones, shales, and sandstones, mildly metamorphosed in places. Three miles south of the mine is the north contact of the granitic intrusive, regarded as Lower or Middle Devonian, which underlies the Tabletop Mountains area. This batholith is about 10 miles long, in a north-south direction, and about 4 miles wide. At Mount Albert, about 5 miles west of the Tabletop intrusion, is a group of basic rocks, amphibolites and serpentinized peridotites, thought to have been intruded at the close of the Ordovician."

Jan 1, 1949

By H. Sakurai, M. Kato, F. Tanaka

The Mitsubishi Continuous Copper Smelting/Converting Process employs an electric furnace (CL- furnace) for settling the slag/matte mixture formed in the smelting furnace. The conditions in the CL- furnace change its settling efficiency, resulting in high variability of copper losses in slag. Modifications of the operation and maintenance procedures for the CL-furnace have significantly and sustainably reduced the copper losses in Gresik smelter to below 0.7%. A series of flow patterns evaluation in the CL-furnace demonstrated how the chemical reactions and settling conditions of the CL-furnace has been improved by the new operating procedures. Settling mechanisms for the matte droplets in the CL-furnace is also discussed using image analysis of solidified slag. INTRODUCTION The Mitsubishi Continuous Copper Smelting/Converting Process employs an electric furnace (CL- furnace) for settling the slag/matte mixture formed in the smelting furnace. Since the top-blowing in the S- furnace agitates the molten bath strongly, matte droplets are dispersed over the slag phase when melts flow out of the S-furnace. Thus, the CL-furnace has an important role to settle and recover matte droplets efficiently. Since many papers have ascribed major part of copper losses to matte droplets suspended in slag (Tanaka 2007; Genevski et al., 2008; Starodub et al., 2016), flow patterns of slag in the CL-furnace can affect greatly on the profitability of smelters which have adopted the Mitsubishi process. PROCESS DESCRIPTION Figure 1 illustrates the Mitsubishi process schematically. The Mitsubishi process is the only system for continuous production of blister copper from copper concentrates and consists of 3 furnaces connected by enclosed launders those ensure the minimum emission of fugitives. In a smelting furnace (S-furnace) copper concentrates are fed with flux, oxygen-enriched air to form a mixture of slag and matte which cascades down to a slag-cleaning furnace (CL-furnace). The CL-furnace settle matte droplets in the mixture on the crucible from which matte is siphoned to a converting furnace (C-furnace), while discharging the cleaned slag (CL-slag). The C-furnace converts matte to blister copper by the top-blowing of oxygen- enriched air.

Jan 1, 2019

By S. Mamonov, V. ?shikhin

"The purpose of work was the significant increase of copper recovery from slag at a concentrating plant. Analysis of study of slag phase composition showed the perspective of a slow slag cooling method due to its recrystallization and transition of primary copper minerals to secondary.Copper content in base slag varied between 0.71 and 0.96%. The study of a degree of copper minerals release of the slowly cooled slag in comparison with a yielding slag showed that in a flotation size grade –0.071 mm of yielding slag the weight ratio of released copper minerals grains is 58.95% against 86.73% in samples of slowly cooled slag. The process flotation sheet consists of three main, one control and two cleaner flotation operations with aftergrinding of middling products. A reagent mode was differed from a factory one by decreasing the slurry pH from 11–12 to 8–9. This paper shows research results of the slurry alkalinity impact on technological indexes of beneficiation (flotation).Industrial testing of a resulted batch of slowly cooled slag at “SUMZ” concentrating plant showed the efficiency of such processing: copper recovery to a copper concentrate increased by 15–19%.INTRODUCTIONIntensive development of mining and metallurgy industries within a 250-year period in the Ural region led to forming of approximately 315 man-made mineral formations at the territory of the Sverdlovsk region. The region contain over 32.5 billion tons of barren rocks and out of balance ores, over 1.5 billion tons of tailings, over 115 million tons of slimes, and over 100 million tons of metallurgical slag (Demin et al., 2000). Latters, at average, contain 407 thousand tons of copper, 2519 thousand tons of zinc, 7 tons of gold, and 150 tons of silver (Rudoy et al., 2011). Wastes generated in mining processing and metallurgical sector of economy contain not only thousands tons of copper and zinc, but cause significant damage to the environment where they are located. The reduction of negative impact of anthropogenic wastes on the environment as well as the storage volume reduction of valuable metals from dump slags is possible by improving the efficiency of the melting and further flotation of slags formed during this process."

Jan 1, 2016

By Jean-Yve Tremblay, Michel Prud'homme

"IntroductionIndustrial minerals include a group of more than fifty minerals which are marketed into almost all the sectors of industry; they are the backbone of many manufacturing industries. Table I shows major end-uses for industrial minerals in manufacturing sectors.At Energy, Mines and Resources, industrial minerals are divided in three major categories: (I) agro chemicals and chemicals, (2) construction mineral s, and (3) ceramics and specialty minerals. A listing of the major groups of minerals is shown in Table 2.Agro-chemicals and chemicals are sold on the basis of their chemical content and purity. Construction minerals or structural minerals are distinguished by their performance as low cost and bulky commodities. Ceramics and specialty minerals are performance-specific and are sold for their property on imparting functions on end-products. Industrial minerals have unique characteristics that are useful in many stages of processing; from crushed size to micronized fillers a single mineral ca n serve a broad range of industries because of its intrinsic properties.The Industrial Minerals Industry in CanadaCanada has a large industrial minerals base and is a world leader in the production of some of them. The total value of product ion of these minerals has grown by 115% over the last 10 years despite the misfortune of asbestos.Industrial minerals have shown remarkable growth in the past 20 years at an average annual rate of 9.2%, compared to 7.8% for metallic minerals. In 1986, the value of industrial minerals rose to $4.9 billion, or 14% share of the Canadian mineral production. Figure I shows the value of production of the mineral industry for the period 1966-1986.The leading segment in industrial minerals segment since 1976 is the chemicals and agro-chemicals sector which has an average annual growth rate of 5.75 % in terms of value of production. During the same period, the growth rate for the whole Canadian mining industry was 1.37% per annum. The chemicals and agro-chemical s sector increased its contribution to the total value of production of 2% to 6070 despite the growing share of fuel minerals with 59%."

Jan 1, 1988

By Leopoldo Gutierrez, Sergio Castro, Lina M. Uribe, Janusz S. Laskowski

"The effect of sulfite and metabisulfite ions on the amyl xanthate flotation of copper-activated pyrite, in distilled water and seawater, has been studied by micro-flotation tests and redox potential measurements. The activation of pyrite was carried out varying copper ions concentration. It was found that in the presence of copper ions in solution, sulfite and metabisulfite are able to depress copper-activated pyrite at neutral or slightly acid pH. After the addition of sulfite or metabisulfite ions the resulting pH is more acidic with metabisulfite ions. A significant increase of the redox potential of the solution was observed as copper ions concentration increased. Then, the initial reducing conditions brought about by sulfite and metabisulfite ions, change abruptly to oxidizing conditions in the presence of copper ions. Under these oxidizing conditions, the metabisulfite showed to be an effective depressant for pyrite mainly in seawater. However, sulfite was a pyrite depressant in both distilled water and seawater. Based on these results, the pyrite depression by sulfoxy-depressants during the flotation of Cu/Mo ores in distilled water and seawater is discussed.INTRODUCTIONDepression of pyrite by sulfoxy-depressants (sulfite and metabisulfite) in the presence of copper ions is an important issue. This is particularly true when pyrite depression in the flotation of Cu/Mo sulfide ores is carried out in seawater. The use of lime in seawater must be avoided because the formation of magnesium hydroxy-complexes and precipitating magnesium hydroxide strongly depresses molybdenite flotation (Castro et al., 2014). In order to solve this problem, one large plant in Chile uses sodium metabisulfite (MBS) instead of lime to depress pyrite in seawater. In plant practice, this also improves molybdenite flotation since with the use of MBS the pyrite depression is carried out at pH 6-7, instead the pH 11-12 usually employed with lime.From a general point of view, pyrite exhibits some natural floatability over acidic pH ranges and may be partially floated without thiol collectors (a coating of sulfur/polysulfides has been claimed). Therefore, pyrite flotation with xanthates is usually high in the acidic pH region, but decreases greatly at alkaline pH (Leppinen, 1990; Fornasiero and Ralston, 1992; Zhang et al., 1997)."

Jan 1, 2016

By Xuanxue Mo, Zengqian Hou

"Yidun Island Arc in Sanjiang Region is one of the important Kuroko-type volcanogenic massive sulfide deposits (VMS) districts in southwestern China. Tectonically, the region is situated in the eastern portion of the Tethys orogenic belt, and is a late Triassic extensional island-arc. The island-arc underwent earlier arc construction, intra-arc rifting, later arc construction and backarc spreading during its evolution and formed a complete trench-are-basin system, i.e., the Ganzilitang suture zone, forearc basin, outer are, intra-arc rifting zone, inner arc and back-arc basin from east to west across the island-arc.Kuroko-type VMS deposits and occurrences discovered so far are limited to within the intra-arc rifting zone of the Yidun Island Arc and tend to occur in groups or clusters distributed in separate faultbound basins; e.g., Zengke, Gacun and Xiangcheng basins, in which submarine volcanic rocks, especially bimodal volcanic suites, were extensively developed. The VMS deposits formed in the waning stages of volcanic eruption in the late Triassic and are hosted in the uppermost section of acidic volcanic rocks (rhyolitic-dacitic) within a bimodal suite. The orebodies are associated with these host rocks: rhyolitic-dacitic pyroclastic rocks and exhalites and chemical sedimentary rocks.All VMS deposits in Sanjiang are of the Zn-Pb-Cu type. The architecture of the deposits is twofold, consisting of concordant lenses and layers of massive sulfides and an underlying discordant stockwork. All deposits show metal zoning. The hydrothermal alteration related to mineralization is strong and asymmetrical, and is found dominantly within the stockwork zone and host rocks surrounding the ores. There are two alteration patterns: (1) chloritization - sericitization - silicification from outer sides to core of the alteration pipe; and (2) silicification + sericitization - silicification + carbonate from the lower to upper part of the alteration pipe.The mineralization temperatures of ore-forming fluids vary in the range 200°C to 335°C. Thermal evolution of the fluids displays temperature profiles that first increase and then decrease with progression of mineralization processes. The majority of black-ore minerals (Groups I and informed during intensifying stages of hydrothermal activity, and the majority of semi-yellow-ore minerals (Group III) formed during a thermal maximum. There followed the formation of fine-grained black-ore minerals (Group IV), which interacted with barite layers during decreasing temperature phases.Oxygen and hydrogen isotope studies show that the sources of ore-forming fluids for the Kurokotype VMS deposits are two-fold: seawater and magmatic hydrothermal solutions, represented by the Kuroko deposits in Japan and Kuroko-type VMS deposits in Sanjiang, respectively. In the latter case the hydrothermal solutions reacted with host rocks and mixed with cold seawater percolating downward, and circulated through volcanic rocks resulting in development of alteration zones and formation of ore minerals in Kuroko-type VMS deposits."

Jan 1, 1993

By Jian Deng, Haitian Sun, Zengqian Hou, Shuhe Song

"Abstract - Volcanogenic massive sulfide (VMS) deposits, an important base-metal deposit type in China, occur widely in submarine volcanic districts of variable magmatic affinities. These VMS deposits range in age from Archean to Mesozoic, but most are in Proterozoic and Paleozoic sequences. More than 60% of VMS deposits formed in the Paleozoic, the most important metallogenic eon. Three important Paleozoic VMS-metallogenic provinces include Northern Qilian, Sanjiang and Altai provinces. The Proterozoic constitutes the next important era, but with no VMS deposits in the middle Proterozoic. VMS deposits associated with the Proterozoic volcanic rocks occur around the Yangtze Platform and in the western Kunlun-Qinling. The Triassic is third in importance, with VMS deposits concentrated in the Sanjiang Tethys. The Archean has only one VMS deposit, on the northern margin of the Sino-Korea Platform.Five distinct compositional classes of Chinese VMS deposits have been distinguished: Cu, Cu- Zn (or Zn-Cu), Cu-Fe, Zn-Pb-Cu, and Pb-Zn (-Cu). The Cu, Cu-Co, and Cu-Zn types of deposits occur sporadically from the Archean to Paleozoic, and are closely associated with mafic and ultramafic volcanic sequences. The Zn-Pb-Cu and some Cu-Zn type deposits are restricted to the Paleozoic and Triassic, and are hosted by calc-alkaline felsic rocks in bimodal basalt-rhyolite sequences, whereas Cu-Fe and Pb-Zn type (except for the Laochang deposit) deposits are restricted to the Proterozoic and occur in calc-alkaline volcanic sequences. As large quantities of marine mafic volcanic rocks were deposited in western China, Cu and Cu-Zn deposits are major types of Chinese VMS deposits.Chinese VMS deposits formed in a wide range of paleo-tectonic settings and depositional environments, such as island-arcs, rifts, aulacogens, and ocean ridge hot spots. Among these, the rift and back-arc environments are the most important, containing about 60% of Chinese VMS deposits. Aulacogens are a subordinate environment where most of the Proterozoic VMS deposits formed. The oceanic ridge and hot-spot systems are common in the tectono-magmatic domains in China, but contain only a few small Cu and Cu-Zn type VMS deposits.The Chinese VMS deposits have usually been influenced by both deformation and metamorphism to various degrees, resulting in changes in the shape and metal distribution. Seven representative deposit styles have been recognized: sheets, sheet plus strata-bound stringer, cyclically zoned deposits, mounds, mound-like deposits, strata-bound stringer-disseminated, and stockwork-disseminated deposits. The formation of these various styles of deposits is controlled by several key factors, such as lithology and permeability of the host rocks, focused or unfocused discharge, temperature and chemical composition (e.g., salinity) of hydrothermal fluids, as well as depth of seawater."

Jan 1, 1999

By A. E. Wraith, J. Protheroe Jones, P. J. Mackey

INTRODUCTION When Victoria became queen in 1837, that technical wonder of the 19th century—electricity— had progressed from being an exciting physical curiosity and was now a field of intense scientific investigation, invention and application. Its role in electrochemistry had been brilliantly quantified by Faraday in 1833–1834, and his earlier discoveries in electro-magnetism were to lay the foundations of electricity generation and the electric motor. In this age of electrical experiment, silver electro-plating emerged as a popular decorative art, at first using batteries to provide the deposition current, superseded by dynamos in the early 1840s. The decorative chemical and electroplating of precious metals was largely pioneered in England by the firm of G.R. Elkington and Co., founded in Birmingham by George Richards Elkington (1801–1865) in 1832, and protected by a series of patents which helped the company establish a leading position in the new field of ‘electrometallurgy’. In the same decade, the technique of electrotyping emerged, the first application of electro- forming by electrolytic deposition. Simultaneously invented by Spenser in England and Jakobi in Russia, but generally claimed for Jakobi, electrotyping involved plating a thick copper layer on to an electrically conducting mould wall embossed or incised with a pattern or profile which would consequently be replicated on the copper deposit—essentially a method of casting by electro-deposition with the mould wall as cathode. Woolrich’s invention of the low voltage magneto-dynamo in 1842 eliminated the need for batteries as a continuous source of deposition power, opening up the possibility of making more massive electroplated deposits, and by the mid-point of Victoria’s reign in 1869, the work of Wilde, Wheatstone and Siemens had produced the self-excited electro-dynamo, capable of higher voltages and yet greater deposition power. In this early Victorian period copper was extracted and refined by methods which had developed step-by-step over many decades. Only relatively rich copper ores containing more than, say, 6% Cu were economically useful, and the final copper product was far from pure. Copper production in Britain was located principally in the Swansea area of South Wales, based upon the ‘Welsh process’ of reverberatory batch smelting and refining, using locally mined coal and ore imported from Cornwall and elsewhere. Silver was an important by-product. Much of the output was exported and South Wales remained a principal supplier to the world copper market until the 1890s. It was here at Pembrey, a few miles west of Llanelli, that a new primary copper smelter was stablished in 1849 under the name Mason and Elkington, arguably to supply the Elkington company’s market for electrotype products.

Jan 1, 2019

By Tony B. Szwilski

"The efficiency of operation and life of an advancing longwall coalface depends, to a great extent. on the face-end roof strata conditions and the stability of the gateroads. The factors that influence the rate of closure of gateroads are examined, in particular the gateside pack and the coal rib (crush) pillars. The performance of mechanized packing systems is briefly discussed. Gateroad deformation surveys were carried out at two coal mines to determine the influence of the rib pillar width on gateroad stability; also, the influence of the gateside pack on the immediate roof and floor strata is analyzed based on strata bed displacement measurements from instruments installed in the gateroad and pack-hole of a longwall advancing face operating in a thick seam (7.55 m). Concluding, an evaluation of the fac e-end systems examined is given and recommendations made f or the most suitable rib pillar width. face-end geometry and roof strata reinforcement.IntroductionKevword s: Coal mining, Pillars, Rib pillars, Ground control, Longwall mining, Gateroads , Packing systems, Roof control. The face-end region of a longwall advancing face is the center of mining activity, being the turn-around point for the coal cutting machine. and the place of gateroad formation and movement of special face-end supports. The design of face-end layouts can be aided by knowledge of strata control parameters, such as the effective loading of the immediate roof strata , convergence of the roof and floor, magnitude and distribution of fractures in the roof strata around the face-end , optimum placement of supports, coal seam thickness and strength characteristics, geometry of layout and interaction from neighbouring workings. Generally, the gateroad is formed by one of three face-end methods: (a) advanced headings, (b) in-line system (gateroad formed at the face) or (c) conventional ripping with or without stable elimination (also halfheading). The quality of gateroad is influenced principally by the face-end system employed, standard of gateside pack and width of pillar. A good standard of gateroad is generally achieved by employing the half-heading face-end system, the gateside pack and coal rib pillar having comparative support/ yield (stiffness factor) characteristics. However, the halfheading is often not favoured due to face operation restrictions."

Jan 1, 1981

By Kenneth Williamson

La découverte de nouveaux gisements métallifères constitue le point de départ du développement de l'industrie minérale. Or, au cours de ces dernières années, le nombre de ces découvertes a fortement diminué dans les territoires classiquement explorés, entraînant une recrudescence de l?exploration dans les terrains géologiques de grade métamorphique élevé (e.g., Province de Grenville, Grand Nord du Québec). Ces derniers ont été traditionnellement considérés comme stériles à cause (i) de la monotonie apparente des gneiss qui les composent, (ii) de la difficulté d?identifier leurs protolites, (iii) des changements importants dans l?apparence des gîtes recherchés reliés au fort degré de déformation et de métamorphisme et (iv) des théories qui prônent un lessivage important des cations et des métaux d?intérêt économique par les processus de déshydratation des roches lors du métamorphisme régional (Weaver et Tarney, 1985; Vokes, 2000). Cependant, l?avancée des connaissances dans la compréhension des gîtes métallifères et de leurs terrains hôtes gneissiques intensément métamorphisés, montre que les systèmes géochimiques des roches altérées demeurent robustes (p. ex. ; Trägårdh, 1991; Craig et Vokes, 1993; Geringer et al., 1994; Schandl et al., 1995; Zaleski et Peterson, 1995; Vokes, 2000; Blein et al., 2003, sous presse). Bien sûr, les sulfures peuvent être localement remobilisés et même fondre, mais cette remobilisation n?implique pas forcément la disparition du gîte hôte (Williams, 1990) et peut s?avérer, bien au contraire, bénéfique pour la rentabilité d?un gîte en augmentant sa teneur en minerais (Marshall et al., 2000). Jusqu?à présent, dans les terrains métamorphiques, les contextes sédimentaires et plutoniques ont été reconnus et respectivement explorés pour les gîtes de type SEDEX et les gîtes magmatiques de Ni-Cu. L?étude de gîtes de métaux de base et précieux intensément métamorphisés (faciès des granulites) et leur comparaison avec des gîtes équivalents peu on non métamorphisés a permis d?établir, au cours des dernières décennies, des outils pour l?exploration des terrains de haut-grade métamorphique (Vokes, 1991, 2000; Slack et al., 1993; Spry et al., 2000). Ces outils sont basés sur la reconnaissance de roches diagnostiques d?une circulation ou d?une exhalation de fluides hydrothermaux telles que les méta-exhalites (formation de fer, coticules, tourmalinites, roches riches en quartz-gahnite, en apatite, en barite ou en staurolite zincifère) (Spry, 2000; Spry et al., 2000). Ils sont utilisés constamment dans les ceintures supracrustales riches en roches métasédimentaires.

May 1, 2003

By A. Mular, T. Bond, G. D. Farnell, J. F. Kingston

"ABSTRACT:-A 60—cm semiautogenous grinding-(SAG) mill was designed -for continuous wet operation in closed circuit with a vibrating screen. The circuit is fully instrumented and automated. Part of the control system incorporates Foxboro SPEC 200 controllers around the pump box to maintain level. The rest of the control system involves an ACTION model BC2 basic direct digital controller that handles all other inputs/outputs and contact closure sensing:·The success of the control system is attributed to the uniqueness of specially designed mass flow metering systems. Various control strategies are possible. Employed to date has been control of a mill load set-point by cascading the deviation from load set-point as the set-point to the fresh feed rate ""controller"". Mill feed water is ratioed to total flow rate of solids fed to the mill. The performance of the circuit is being correlated with the performance of full scale SAG circuits in British Columbia to develop models, to assess the feasibility of scale up and to investigate the effects of design variables on responses such as circuit throughput. 1 INTRODUCTIONWhere ore types are appropriate, semiautogenous grinding and/or autogenous grinding (AG) has replaced conventional grinding. Secondary/Tertiary crushing plants are thereby eliminated so that capital expenditures are less and overall comminution costs can be lower (Barratt 1982). To establish the suitability of an ore for SAG circuits, pilot scale tests with 1.7 to 1.8 M diameter mills are often conducted. At least one test per ore type in a deposit has been necessary. Often, each test involves a large amount (up to 50 tonne) of sample, so that the testwork can be expensive and may discourage the use of SAG or AG circuits. However, MacPherson (1977) has employed a continuous 45 cm dry Aerofall mill circuit closed with screens and an air classifier to determine whether ores are suitable for SAG milling. The amount of sample per ore type is of the order of 60 kg or less. Thus an established SAG mill scale up procedure that employs small circuits is highly desirable.The purpose of this paper is to describe a small 60 cm wet continuous SAG/ AG mill pilot circuit assembled at the University of British Columbia to study the feasibility of scale up, to assess the influence of design variables, to develop mathematical models and to evaluate the effects of alternative control strategies on circuit performance"

Jan 1, 1988

By L. A. Nazarova, M. Vandamme, L. A. Nazarov, R. I. Rodin

"The paper describes a new method of interpreting the “canister test” data for the quantitative estimation of gas-kinetic parameters of coal bed based on the developed model of gas emission from coal sample placed in a sealed container. The model accounts for grain-size composition of the sample, initial gas content S, as well as coefficients of diffusion D and mass transfer ?. The inverse coefficient problem is formulated to find S, D and ??from the data of pressure measurements in the sealed container. It is shown that the inverse problem is uniquely solvable if the pressure is dropped during the experiment. The method has been tested using the data from an underground coal mine in the Kuznetsk Basin.Based on the poroelastic model of a coal bed and Khristianovich’s concept about origination and evolution of the filtration zone F in the neighborhood of a degassing borehole the authors considered the corresponding direct problem on rock mass geomechanical state. It was offered interpretation method for data on pressure measurements in a plugged degassing borehole allows evaluation of the diffusion coefficient, the horizontal component of natural stress field and parameters of F. The related inverse problem of the mixed type is formulated, and the cost function is constructed. The analysis using synthetic input data has shown that the cost function has a number of local minimums arranged on the same straight line, one of the minimums being the inverse problem solution. INTRODUCTIONPre-mine degassing is an integral part of coal mining. It allows mitigation of induced accidents in mines (coal and gas outbursts, rock bursts) (Guide, 1990; Malyshev & Airuni, 1999; Seidle, 2011) and also furnishes an alternative and ecology-friendly energy source—methane (Rice, 1997; Nambo, 2001). Choosing an optimized pattern of degassing boreholes, as well as estimating degassing time and amount of gas recovered requires data on gas-kinetics indices of coal beds out of which the key parameter is a gas content S. According to the latest guidelines for coal mines in Russia (Ruban et al, 2012), mining is allowed if S in a coal bed section is under 7 kg/m3."

Jan 1, 2015