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By Al Gagnon

Since start-up in 1972, many circuit problems have been encountered, most of which were related to the abundance of fines (-28 mesh), which the circuit had not been designed to treat. The major problems associated with the original circuit included excessive loss of magnetite, reduced throughput during periods of a high proportion of fine coal in the plant feed and low yield in the fine coal circuit. This paper outlines the coal processing circuit at Fording Coal Limited as it exists today, with emphasis on the changes to the original fine coal treatment circuit.

Jan 1, 1978

By V. Bruned, K. Mohamed, A. Michaut

Orano Mining Somaïr uranium treatment plant (Niger) uses a pugging-curing process to leach uranium. Sulfuric acid, nitrates and water are added to the finely grinded ore in a rotary drum to leach uranium bearing minerals and solubilize uranyl sulfate ions. Reagents, sulfuric acid and nitrates, are the main OpEx of this process step. The economical optimization of their addition requires a thorough knowledge of the ore behavior in solution with these reagents. Orano Mining technical direction and Somaïr laboratories developed a model to predict the curing process uranium recovery surface with a limited number of parameters. Experimental laboratory work to fit the model needs to be done for each type of ore which can require a lot of metallurgical tests and would be time consuming. In order to optimize the required number of tests, an innovative experience plan was designed in parallel to the development of this model reducing the required number of tests to only eight. Once the parameters of the models are correctly fit, the comparison between the estimated values and the actual values for the uranium recovery is excellent (less than 0.5% error in average). Associated with an updated cost model of the curing process, this new recovery model helps the plant operator find the best set of reagents to maximize curing process profitability in the Somaïr plant day after day.

Jan 1, 2020

By Ozdemir. O.

Magnesium additions to aluminum enhance strength and hardness, lowering density, and improving corrosion resistance. However, during melting and casting processes, significant amounts of magnesium are lost due to selective oxidation. Preventing these losses would reduce the production cost and improve the quality of the final product. The effects of strontium addition on the oxidation behaviour of aluminum-0.5% and 1% magnesium alloys were investigated by monitoring sample weight gains with time with a thermogravimetric balance at 750°C. Sample cross sections have been examined using Field Emission Gun Scanning Electron Microscope.

Jan 1, 2004

By Paul W. Richardson

"Introduction And AcknowledgmentsTHIS PAPER outlines the geology and discusses the geological problems of the Mindamar mine. It is impossible to acknowledge the contributions of ideas of all the geologists who have worked in the area. Among the more important contributors are K. DeP. Watson, W. S. James, B.S.W. Buffam, and L. J. Weeks, and John MacPherson, the resident geologist at the mine.A mineralogical and chemical study of the ore and country rock is being carried •on by Dr. Watson at the University of California, Los Angeles.General InformationThe Mindamar mine is on Cape Breton Island, forty miles south-west of Sydney (Figure 1). The nearest railway stations are at St. Peters, which is thirty-two miles southwest of the mine, and at Sydney. Good gravel-surfaced roads connect the mine to the railways.The mine is producing at the rate of 600 tons a day of ore containing zinc, lead, copper, and minor amounts of silver and gold. At the present time the mill feed averages 9 .per cent combined metals, of which zinc makes u:p 7 1per cent and lead and copper each 1 per cent.General GeologyThe ore being mined ,by Mindamar occurs in a shear zone parallel to a northeasterly striking, vertically dipping, series of rocks consisting of rhyolite tuff, rhyolite, minor more basic flow rocks, and diorite (Figure 2). In the vicinity of the mine, these rocks have been termed the Mine Series. They belong to the Bourinot group, which has been assigned by L. J. Weeks to the Middle Cambrian. At the latitude of the mine, the Bourinot group is bounded on the northwest by the Stirling fault and extends eastward for two miles."

Jan 1, 1953

"With the globalization of the mining industry, many companies are now seeking to invest in underground diamond mines, with the purchase of small diamond pipes being seen as particularly attractive. However, recent experiences in South Africa have shown that many projects fail due to a lack of awareness of the hazards associated with diamond mining. In this paper three significant hazards are dealt with — mud rushes, block crushing, and implementation of an inappropriate mining method. Measures that assist in the prevention of these three hazards are given.IntroductionFor over a hundred years, South Africa has been seen as the centre of the diamond mining industry, possibly having the largest number of operational underground diamond mines in the world. Despite the fact that this industry has been dominated by large mines of De Beers Consolidated Mines Limited, many small underground mines have operated profitably for a number of years, exploiting diamondiferous fissures and pipes. In the last decade there has been renewed interest in these small operations from international companies. However, many of these projects have not realized their full potential owing to a lack of appreciation of the hazards inherent in the operation of a diamond mine.Hazards Associated with Diamond MiningIn the development of a diamond mine, the mining company must be aware of the hazards associated with diamond mining. There are three main hazards: (1) mud rushes; (2) block crushing; and (3) selection of an inappropriate mining method (not a natural hazard, but a planning induced hazard). Each of these hazards will be dealt with in turn in the following sections."

Jan 1, 2000

By Libao Zhu, David J. Williams, Nazife Erarslan

"Statistics show that the drawbell in underground mines is usually subjected to significant damage by impact loading due to falling ore. Drawbell damage causes a large quantity of residual ore to remain on the drawbell, thus leading to a huge waste of ore resources. In this study, the Cavity Monitoring System (CMS) and Surpac software were employed to visualize the 3-D damage. Also, the Discrete Element Method (DEM) was employed to perform simulations of the falling ore to investigate the damage evolution of drawbells under repeated ore impact and obtain the dynamic damage accumulation mechanism. The reason of drawbell damage was found due to the micro-shear cracks. The numerical simulations of a drawbell damage process under repeated impact loading showed the main failure type was shear failure and this type damage was found increasing with more ore falling. INTRODUCTIONDrawbells are an important part of underground mines and play a significant role in ore recovery in terms of safety, economy and efficiency (Brunton et al., 2010; Hustrulid & Bullock, 2001; Trueman et al., 2002). In most cases, blasted ore is gravitated along the drawbell and finally arrives at the footwall of the drawpoint. However, some of the blasted oversize ore blocks clog the drawbell road and those ore pieces are called hang ups (Penswick, 1997). However, any damage on a drawbell is believed to be the reason for these hang-ups. In the literature, researchers have reported that the stability of the draw-point is influenced by the stress distribution above and near the drawbell (Butcher, 1999; Neverov & Neverov, 2013). Much research in the literature has been done on draw-points in underground mines. In fact, rockfalls cause very serious damage on a small impact area in a very short time (Volkwein et al., 2011). Hoek (2000) pointed out that the blasted ore causes progressive ravelling and even collapse of the drawpoint, thus the ore in the stope is abandoned. In this paper, the Cavity Monitoring System (CMS) was employed to obtain the damage profile of a drawbell due to the impact of rockfalls and to confirm the residual blocking ore on the damaged drawbell. Then, the drawbell damage evolution due to repeated falling ore was simulated by the Discrete Element Method (DEM)."

Jan 1, 2015

By Roderick C. McDonald

Great Bear lake, the fourth largest body of water on this continent, comprises an area of approximately 12,000 square miles, and is set astride the Arctic circle, with a large portion of it witnessing both the Arctic winter night, and the Arctic summer day with its midnight sun. The very name itself, Great Bear, suggests an Arctic region. The seasonal contrasts at Great Bear lake are very marked by the cold and darkness of winter, and the warmth and brightness of summer. Signs of winter such as low clouds, snow, sleet, fog, and night frosts, generally appear the latter part of August, while ice forming on bays during the last two weeks in September ends boat travel on the lake about September 30th.Early in June the ice leaves the river mouths, during the last ten days of the month it disappears from small bays, and at some time during the last two weeks of July the main body of the lake becomes navigable. In 1916, the ice disappeared earlier than usual, and the lake was navigable on July 5th. Great Bear river generally breaks up about June 1st, but, on account of ice cliffs and floes, it is not navigable with safety until early in July. Even then, the traveller is confronted with the Charles rapids, but these might be overcome by a wagon or motor road, such as the one from Fitzgerald to Fort Smith: However, in 1931, Mr. A. W. Boland, Fort Norman, N.W.T., carried with scow and motorboat practically all freight between Fort Norman and LaBine point and Hunter bay, at the east end of the lake. During July and August, two types of clothing are required, for, although the days are mainly ones of warm sunshine, the nights are cloudy and cold. In the winter season, fur clothing is used exclusively. Considerable timber, mainly white spruce, suitable for fuel and building purposes, borders the lake and extends eastward to the Coppermine river. North of the lake, no timber is found except in the river valleys, but with oil and coal possibilities near Fort Norman, the fuel situation might be solved.

Jan 1, 1932

By A. M. Bell

"Hallnor mine is in the township of Whitney, Porcupine district. To date, its production of gold has been second largest in the east Porcupine field. Ore was discovered in the property in 1936 by diamond drilling in overburdened country. This drilling was undertaken by Noranda Mines following the discovery of ore in conglomerate at Pamour 1 mile to the east.Milling commenced at the Hallnor in June 1938, and to the end of 1945 432,000 oz. gold had been produced from 889,000 tons of ore, giving an average recovery of 0.49 oz. a ton.The West mine of Pamour, the Broulan orebody, and the veins on the Hallnor and Bonetal are all parts of a mile long vein system that has been separated into three sections by cross faulting. In consequence, they could well have been described in one paper. In treating them individually the viewpoint obtained from each may lead to conflicting opinions, and any conclusions advanced in this paper on the general structure should be modified by the conclusions advanced in papers on the neighbouring properties.GENERAL GEOLOGYRock FormationsThe Hallnor orebodies occur within 400 feet of the contact between lavas and sediments, and may lie in either lavas or sediments. The lavas near the ore consist of flows of pillowed andesite and one flow of more acid and less sheared and chloritized lava locally named trachyte. These flows strike east-west and dip steeply. At the surface on the east side of the property the volcanics have been intensely altered to a massive carbonate rock having a north-south thickness in excess of 1,000 feet . This carbonate body extends west across the property with a plunge of 45° (Fig. 1)."

Jan 1, 1954

By O. E. Andrew

THE object of this paper is to present a brief summary of the dust control system in use on the 3,825-foot level at the jaw crusher station, Lake Shore mine. During the years 1936 and 1937, dust survey reports were presented to the management showing that high dust concentrations were being created during operating periods. At that time, however, this crusher was running only an hour or so each shift, and it was felt that no large capital expenditure for dust control equipment could be justified. In order to afford some protection to the operators, a number of respirators then on the market were .tested and the 'Comfo' respirator was adopted for use by the crusher-men. In 1938 this crusher began to handle a large share of the total mine tonnage and the hours of operation were increased. Further dust sampling showed increased dustiness with the longer operating time. It was also realized that the operators suffered considerable inconvenience if they wore their respirators throughout the shift. If the respirators were not worn, then dangerous amounts of dust were being inhaled. The fact that the crusher station was situated on the 3,825-foot level limited the means that could be employed to eliminate the dust hazard. At that rime there was not available the 5,000 c.f.m. of fresh air which would be required to sweep out or dilute0 the dust, and there was also no way of disposing of the contaminated air without passing it on for other men to breathe. Thus it became apparent that a self-contained dust disposal system would have to be installed.

Jan 1, 1941

By C. Cortés

Flotation is a highly interactive process where a change or disturbance in any part of the circuit results in different final grades and recoveries. This high variability of the circuit metallurgical performance complicates the diagnosis of the scavenger stage at the end of the line, as copper losses in the final tailings are erratic and not totally a consequence of problems in the scavenger section. The assessment of the scavenger performance requires a more elaborated procedure than that used for others stages of the circuit. This communication describes the application of an approach that combines results of laboratory flotation tests with those of surveys performed at the plant. The approach is based on running surveys in one of the circuit lines to collect samples for determining grade vs. recovery curves for total mass and size-by-size fractions. Full mineralogical and liberation analyses are also considered on some samples of the feed and tailings streams selected to have a range of feed grades. A separate sample of the feed is used to run laboratory flotation tests to determine optimum flotation time. Two additional pieces of information are the effect of operating variables on recovery, determined through a test program based on design of experiment techniques, and operational data on every cell in the line gathered by visual observation. The application of this approach to one of the scavenger lines at Los Colorados concentrator (Minera Escondida, BHP Billiton) is demonstrated.

Jan 1, 2007

By P. Reyes

The Codelco Chile El Teniente Division Caletones Smelter has an objective to smelt 1,250,000 tonnes per year of copper concentrate. This is a great challenge for the smelter facilities and particularly for the acid plants. The analysis ensuring that there are no obstacles to achieve the production capacity was of great importance. Therefore a series of activities were undertaken as well as studies dedicated to reach the target. This paper presents work focused on a fluid dynamic study, translated in an operation methodology of integrated handling of the smelting and converting gases with the objective to optimize the gas flow and S02 concentration. The optimization should be done employing the current installations, equipment and instrumentation and/or minor modifications. In the first part of the work the condition of the instrumentation involved in the gas handling was checked, improvements determined and the corresponding corrective actions were carried out. The proposed operation method consists of operation of the Cleaning Gas Plant 2 (TC' s gases) and operation of Gas Cleaning Plant 1 (the remaining gas plus the gases from CPS). The implementation of the operation method involves the modification of the valve of the gas into the duct to plant 1 from On to Off to modulate flow. After modification a three days test was carried out. To evaluate the tests, a "Sulphur Capture" indicator was used. During the test the behaviour of the effluent treatment plants was closely examined. No problems or unusual operating conditions were observed. The reduced flow of gas to Gas Cleaning Plant No. 1 permitted the start up of the 2nd test day treating most of the gas received by Gas Cleaning Plant No. 2. The operation was carried out with the limitation not to increase the effluent pond level, which was maintained constant.

Jan 1, 2007

By K. Soga

DOWA has long been specialized in the treatment of complex massive sulfide ores from exploration through smelting. Its competitive advantage derived from ore dressing technology to dress and concentrate complex ore to various kinds of metals concentrates. With this technology, the company recovers as many as seventeen different nonferrous metals. Therefore, it is crucial for the environment management and recycling business both to recover valuable elements like gold, silver, copper etc. and to handle hazardous elements in safety. From this view point, the nonferrous metal industry has a potential to play an important role; that is "The Anchor of Recycling" or "The Joint of Recycling Loop". By utilizing these mining, smelting and refining technologies, know-how and facilities, DOWA became a leading waste treatment, soil remediation and metal recycling company in Japan. This knowledge is now being applied in China .

Jan 1, 2007

By D. K. Sarkar, Ying Huang

"Superhydrophobic thin films were fabricated on aluminum alloy substrates by chemical etching followed by passivation with organic acid molecules; (ii) electrophoretic deposition (EPD) of functionalized ZnO nanoparticles and (iii) electrodeposition of organic-inorganic composite materials. The physical and compositional analyses of the deposited thin films were characterized by SEM, FTIR, XRD as well as contact angle goniometer. The contact angle and surface roughness of the superhydrophobic surfaces prepared by the chemical etching process were found to be 156° and 2.29 µm, (ii) by the EPD process were found to be 155° and 4.54 µm and (iii) by the electrodeposition process were found to be 159° and 7.11 µm, respectively.The corrosion properties were analyzed with both polarization and electrochemical impedance spectroscopy (EIS) in NaCl aqueous solutions. The results demonstrate that the superhydrophobic thin films on aluminum alloy substrates display better anti-corrosion behavior than the as-received aluminum substrate. The comparison of results pertaining to the compositional and corrosion properties of these thin films on aluminum will be discussed in this work.INTRODUCTIONSuperhydrophobicity is defined as a surface property which provides non-wetting characteristics with a water contact angle larger than 150°. It is observed that the creation of certain micro-nanoroughness structures promotes the entrapment of air in the spaces of the rough surface morphology. In addition, lowering the surface energy helps to reduce the affinity of water drops to the surface, thereby weakening the water-surface interaction. Recently, various fabrication methods for superhydrophobic surfaces have been explored (Sarkar, 2010, Huang, 2010, 2011, 2013, 2015a, 2015b), such as the sol-gel process (Brassard, 2011), plasma treatment (Marchand, 2013), chemical vapor deposition (Zheng, 2009), chemical etching (Saleema, 2011), electrodeposition (Ying, 2011) and electrophoretic deposition (EPD; Huang et al., 2015b)."

Jan 1, 2016

By Jerry Ran

When multiple levels are mined in open stope mining with delayed backfill, mining underneath fill is inevitable to achieve higher rate of recovery if no sill pillars are left for the purpose of fill separation or partial ground support. This is particularly true when the orebody has low reserves per unit vertical distance. Instability of the exposed fill back causes stope dilution, production delay and possible equipment damage and consequently increases the mining cost. Previous studies have concentrated on fill mat stability in cut-and-fill and stability of fill walls in open stope mining. Workers are exposed to the fill back in cut-and-fill and therefore smaller open spans are normally adopted and the fill mat is reinforced. In open stope mining openings with large spans are designed, workers are not exposed to the fill back and its stability has to be maintained by fill of sufficient strength. However, the required fill strength is normally determined by considering different modes of fill wall failure. The fill back stability is usually not analyzed in the fill design process. The lack of analysis on fill back stability for open stope mining is mainly due to difficulties in relating the fill properties to the fill and stope geometry. In this paper a simplified wedge model is adopted to analyze stability of the exposed fill back in open stope mining with consolidated backfill. The proposed method calculates the factor of safety of the fill back against shear failure under known fill and stope geometry and fill strength parameters in order to assess the fill back stability. It can also be used to determine the required fill strength with known fill and stope geometry. The proposed approach is indirectly validated by mining experience and observations at two operating mines. In addition there are many factors affecting the fill quality and stope configurations in an operating mine. These factors have to be considered in the analysis of fill back stability. This situation is highlighted by presenting an actual mining case where the fill back failed due to factors commonly encountered in mining operations.

May 1, 2003

By M. N. Pons, E. Benizri, B. Laubie, A. Bani, Université de Lorraine LRGP, P. Kidd, A. J. M. Baker

"Serpentine (i.e. ultramafic) outcrops in Europe cover more than 10,000 km2 and have a low-fertility and low-productivity, making them unattractive for traditional agriculture. In general, these areas are slowly abandoned by local farmers, affected by strong rural exodus and landscapes undergo a process of closure. However, ultramafic landscapes have the potential to provide multiple ecosystem services that can contribute to Europe’s goals towards insuring food security, production of renewable raw materials and renewable energy. Phytomining (agromining) aims at cultivating metal hyperaccumulator plants that are able to accumulate Ni and other strategic elements from metal-rich soils and transport them to the shoots (>1%), which can then be harvested as a bio-ore. Such metal-rich biomass can be used to recover highly valuable metals, e.g. nickel (Ni) and also to produce energy (heat, electricity). Nickel agromining can thus offer an eco-efficient alternative to classical pyro- or hydrometallurgical processes without disturbing the soil cover and the geology from soils and rocks that would be considered as low grade ores or sterile material for conventional mining methods.Phytomining agroecosystems can lead to better soil resource efficiency and can offer a fully integrated, new agromining agriculture that could cover thousands of km2 in Europe, benefit local communities with a sustainable rural development and provide a wide array of ecosystem services which will need to be optimised under a life cycle assessment methodology:1. Production of bio-sourced metal products2. Production of energy biomass3. Restoration of soil fertility for conventional agriculture (Ni stress)4. Limiting Ni intake by local populations and farmers5. Use and conservation of local biodiversity (plant and soil fauna and microflora) as cultivated ecosystems6. Store carbon in cultivated soils7. Enhance pollination activity at landscape level.Nickel agromining could therefore change the economical balance in historically-disadvantaged ultramaficregions of Europe"

Jan 1, 2016

"Since World War II, urban communities have expanded at an unprecedented rate. The industrial mineral industry supplies the sand, grave], limestone, crushed rock, cement, gyp-sum, etc. for urbanization. Most de-posits in use are close to or within communities. Pollution of water and air has become a matter of public concern. Waste disposal and the effects of noise and vibration are subjects of public debate. Need for the reclamation of land after operations such as strip mining is discussed in magazine articles and on TV pro-grams; i.e., the general public is educated in the unattractive features of mining.Legislation is on the books and being drafted to regulate mining operations and their side effects. To avoid over-regulation and restrictive legislation, it is necessary that the public be educated and legislators informed of problems peculiar to the mining industry. Our side of the story needs publicity."

Jan 1, 1968

By Muhammad Tawalbeh

The calculated temperature history of a single particle of MgCl2 hydrates when it came in contact with fused salt electrolyte at 650 °C was determined using the measured heat transfer coefficient for the molten salt bath at 650 °C. The calculations revealed that the entire interior of the particle reached the temperature required for the formation of MgOHCI from hydrated MgCl2 in less than 2 seconds. This was much less than the time required for dissolution of the prills as observed in experiments. It is very likely that the formation of MgOHCI during prill dehydration and dissolution is a result of hydrolysis in the interior of the prills.

Jan 1, 2004

By Lev Filippov, Saeed Farrokhpay

"Flotation process has had less success to recover nickel from laterite ores. Nickel in laterite ores is often finely disseminated in various minerals in very fine size. Therefore, fine grinding should be used to liberate nickel containing particles. Particles resulted from fine grinding are often very fine, and recovery of such particles is generally low using conventional flotation methods. One option to overcome this problem is enhancing the particle-bubble interaction by increasing the particle size and forming flocs. Selective flocculation of fine particle can be therefore the key to enhance the flotation performance of low grade laterite ores.INTRODUCTIONThe majority of the world’s nickel resources occur as laterite ores which are complex, low grade and expensive to treat using conventional smelting and high temperature and/or high pressure autoclave methods (Xu et al., 2013). While about 70% of the nickel resources are contained in laterites, only 40% of the world’s nickel production comes from these ores. Researchers have tried to improve the nickel laterite flotation recovery by using a number of feed preparation techniques. For example, in a study on a laterite ore sample from Australia, flotation tests on a narrow sized fraction of 38-75 µm resulted in only a small increase in the nickel content, from 1.0% to 1.4% (Quast et al., 2015a). In fact, no physical separation technique (including flotation) has been able to dramatically upgrade nickel in laterite ores (Quast et al., 2015b). Thus the challenge of processing low grade nickel laterite ores still exists. This paper aims to explore the possibility of applying selective aggregation in pre-concentrating of valuable minerals in nickel laterite ores."

Jan 1, 2016

By K. Hawboldt, J. E. Halfyard, C. Bottaro

The removal of sulfur from leach residues has been practised in the zinc industry using a combination of flotation and hot melt filtration. The process is highly dependent on the nature of the concentrate and the subsequent residue. When the mineral constituency of the residue alters, the process can encounter significant operational challenges. An alternate method of converting elemental sulfur to water-soluble polysulfides was applied to leach residue from Vale's nickel demonstration plant in Argentia, Newfoundland. Reaction parameters, sulfur purity and other key indicators are discussed as is the potential commercial application.

Jan 1, 2011

By E. Burdukova

Long-chain primary amines are utilized as collectors in potash ore flotation. Krafft temperature of long-chain amines in brine is about 100 °C, and this makes such amines practically insoluble in brine at room temperature. When dodecylamine, melted at 70 °C and dispersed in hydrochloric acid (or acetic acid) aqueous solution, is added to a KCl-NaCl saturated brine at room temperature, the amine precipitates. The experimental results demonstrate that the precipitating amine hydrochloride particles are selectively abstracted by KCl particles, but not by NaCl particles.

Jan 1, 2009