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By Edmond Chow

Shovel bucket blast fragmentation analysis is an alternate way to assess blast performance and its effects on downstream mining processes. A camera is installed on the boom of cable shovels, and the stick of hydraulic shovels. Images are captured automatically as the shovel digs, and are processed to acquire rock size information. The automatic data acquisition makes this method safe to use with minimal manual labour. It also allows for a large set of sample data to be captured from both the surface and the interior of a bench face. The system has been deployed in several mines to provide an objective assessment of blasting performance. Images are captured from their cable or hydraulic shovels. The images are grouped into sets based on the shovel location and time to match the fragmentation to specific blasts. Blast fragmentation reports are created for each blast after reviewing the results. Measuring blast fragmentation from the shovel bucket proves to be an effective alternative for blast performance assessment with unique advantages. The blast fragmentation information has been valuable to the mines, and the mines have begun adopting it into their operations.

May 1, 2011

By W. A. Crosby, W. K. Smith, K. L. McDonald

"IntroductionThis paper describes how the introduction of two blasting techniques and the resuItant development of new dragline digging methods have increased the productivity of single- and double-seam dragline operations at the Rietspruit opencast mine.LocationRietspruit , one of South Africa's largest opencast strip mines, is situated some 11 5 kilometres east of Johannesburg in the Witbank coal field.BusinessRietspruit is a joint venture between Transvaal Consolidate d Land and Exploration Company (T.C.L.) and Shell, South Africa. Rietspruit is administered and managed by Rand Mines, the Mining division of Barlow Rand, transportation and marketing being the responsibility of Shell. The total saleable coal product, approximately 5,5 million tons per annum, is exported via Richards Bay.Presplitting and Throw BlastingPresplitting was initially introduced in September 1980, as a means of dewatering t he overburden and mid burden to facilitate the use of dry-mix explosives a s opposed to slurry explosives.The utilization of the throw blasting technique arose as a direct result of observed ground movement after the successful introduction of presplitting. The first trials commenced in March 1981 on the double-seam operation. The methods, economics and resulting advantages are fully described elsewhere. A brief description follows.Method of PresplittingAfter determining the desired presplit line, 250-mm holes are drilled to top of coal at 4-m to 6-m intervals, dependent on the competency of the rock overlying the coal. A single 60-kg charge of slurry explosives is located at the bottom of each hole, no tamping is used and all the holes are detonated simultaneously. The results are a competent, straight, vertical highwall. This enables accurate control of the first row of blast holes closest to the highwall, which is a prime requisite for successful throw blasting."

Jan 1, 1983

By P. W. A. Mayer

"As the push toward the northern regions of Canada steadily increases to exploit the rich mineral reserves, interest is steadily rising in respect to accessibility and climatic conditions and the problems posed thereby. In twelve years of operation, the Iron Ore Company of Canada, and associated companies, have found, through advanced technology, ingenuity and, most of all. need, some of the answers to the running of a profitable year-round open-pit mining operation."

Jan 1, 1966

By R. R. Bassermann

THE property of Howey Gold Mines, Limited is situated at Red Lake, Ontario, one hundred and seventy-five miles east of Winnipeg and eighty miles north of the Canadian National Railway line. The mine has been a continuous producer since April, 1930, and at present is hoisting 1,350 tons of ore per day. The shaft consists of three compartments (see Figure 1, sketch B). Hoisting is done by two skips in balance, one of which is interchangeable with a cage. Sinking had been carried out at three different periods. From the surface to the 550-foot level, the sets had been spaced at seven-foot intervals, from the 550-to the 1,060-foot level at six feet, and from the 1,060-to the 1,500-foot level at five feet. During the five years of operation, the shaft had become so badly worn, due to spill from the tipples and, to a certain extent, from the loading pockets, that re-timbering was considered necessary. It should be explained that no crushing is done underground because of the ad verse effect this would have on the efficiency of the sorting. The grizzly rail clearance above the ore pockets is fourteen inches and consequently the ore hoisted is extremely coarse. More than average spill from the loading pockets and tipples under such conditions is inevitable, and it is debatable whether underground crushing with consequent increased sorting costs would not be justified. The cost of complete re-timbering according to standard practice would have been prohibitive both directly and indirectly: A lengthy shut-down of the shaft, with the consequent disorganization of the staff and workmen, could not be considered. Accordingly, it became necessary to devise some method of repair that could be carried to completion in a very limited period of time. The shaft timber for the first 250 feet was not in need of repair. From the 250-foot to the 1,060-foot level the wall plates, posts, and blocking were in good condition. These had been protected by a one-inch plank lining put in at various periods during the past three years without interfering with hoisting operations. The end plates and dividers, however, could not be protected in this manner because of the lack of skip clearance. It was decided that, if the dividers in this section could be replaced, the shaft would be as satisfactory as if completely re-timbered. Several factors had to be taken into consideration in deciding on a suit-able method of repair. In the first place, the tipple plates had to be re-designed. To complete the job in a reasonable time, not only had work to be done on the tipple, but simultaneously from several points in the shaft itself. Since all power cables, pipe lines, etc., were in the manway compartment of the shaft, this compartment had to be left undisturbed.

Jan 1, 1935

By D. W. I. Griffiths, J. C. Bélanger

"La Division Matagami de Minéraux Noranda inc. a profité de la construction de sa nouvelle mine (Isle-Dieu) pour continuer sa modernisation.L'utilisation d'automates programmables (PLC) s'est intensifiée pour contrôler et automatiser de plus en plus d'équipement dans ses minessouterraines, au concentrateur, dans les atelierset bureaux.Tous les PLC comrnuniquent entre eux et les IBM PC sont utilisespour exterioriser l'information et faire Ie lien entre Ie personnel et les automates. Le système Central IBM 36 emmagasine les donnees traitees par lesPLC (a travers les PC). Ces donnees sont transmisesau programme d'entretien de chaque equipement et compile les heures, cycles, tonnes, etc., fait imprimer automatiquement les feuilles d'entretien préventif ', etc.Les principales realisations adate et en progrès pour la mine Isle-Dieu sont:• automation complète du système de remblayage du concentrateur ala mine Isle-Dieu situee a2 km de la mine principale;• automation du fonctionnnement des ventilateurs qui comprendra la position des portes de ventilation, Ie chauffage, Ie débit, etc.;• automation des pompes, surveillance des sous stat ions électriques, concentration des gas (CO, SO2) à chaque niveau en tout temps et du propane à l'entree d'air frais;• tonnage et cycles par Ie treuil; et• contrôle d'autres équipernents à differénts niveaux. D'autres travaux furent egalement effectues par les employes, tels que:• la conversion d'un Scooptram ST5A de diesel à électrique;• I'installation complete de systèmes de depoussierage a I'eau (scrubber) pour le concassage secondaire;• I'installation d'un marteau hydraulique avant les concasseurs coniques;• la rénovation des cellules de flottation ; et• l'installation d'un système de gardiennage par caméra. D'autres projets seront effectués ou étudiés:• automation d'un Scooptram"";• automation d'un marteau hydraulique;• récupération de Scooptrarn; téléguidé:• gestion de l'énergie, contrôle de la demande, surveillance et contrôle de l'équipernent de machines fixes(compresseurs, boulloires, pompes à vide, génératrices, débits et pression d'air, eau pour diagnostiquer les problémes, analyser les coûts;• concasseur portatif pour fabriquer de la pierre concassée pour utiliser dans les chemins sous-terre, et• utilisation de micro-ondes pour transmettre les images captées par camera."

Jan 1, 1990

By R. Fukuzawa

"The objective of this research is to evaluate the magnitude of carbon prices required to drive process development and innovation for the global nickel industry in a direction that tackles the multifaceted sustainability challenges that the industry faces, including air pollution reduction and greenhouse gas abatement. The results suggest that the currently considered carbon prices are not sufficient to drive innovations in processing methods or upstream pollution prevention. The co-benefits of climate change mitigation and pollution prevention cannot be readily realized under climate change policy alone. Increased coordination between climate change policy and performance-based environmental legislation is necessary. INTRODUCTIONNickel is an important metal in our modern society as it is used in stainless steel, alloys, electroplating and rechargeable batteries, all of which are integral to our economic growth and development (Eckelman, 2010).However, nickel production is energy intensive and therefore susceptible to emerging climate change policies, which may lead to production curtailment and/or increased unit costs of production unless changes in efficiency or energy sources are made (Mudd, 2010). The industry is faced with multi-faceted constraints: future technology must not only deal with metallurgical, financial and environmental constraints but also promote low energy and low carbon practices. This presents a challenge for this industry where technology innovation, development and commercialization are often lengthy, risky and costly processes (Imrie, 2006).Climate change is one of the many challenges faced by our society. Others include other pollution to air, water and land, resources shortage and economic development. From a policy perspective, it is important to balance multiple and often competing needs in an integrated manner. It would require some levels of trade-off in order to maximize the overall effectiveness but also to ensure that one policy does not undermine other policy objectives.The aims of this study are to evaluate how developments in climate change policy would affect the nickel industry in the context of existing environmental regulations and how the industry could respond under these constraints."

Jan 1, 2012

By W. S. Hegler

Introduction The San Antonio mine is on the north shore of Rice lake, thirty miles east of lake Winnipeg and 120 miles northeast of the city of Winnipeg. Since production was started in 1932, about 2,000,000 tons of ore have been mined. Currently in progress is an extensive development programme which involves 11,500 feet of crosscuts, 3,800 feet of raises, 1,753 feet of shaft sinking, and 160,000 cubic feet of slashing, all in footwall waste rock. It is the purpose of this .paper to indicate the necessity for this work and to describe the methods employed to carry it out. Where unknown factors are as prevalent as they are in the average Canadian gold mine, a definite answer cannot be given as to what is the most economical and efficient system for mining dipping deposits. At San Antonio, the host rock for the orebodies, locally termed basalt, occurs as a sill some hundreds of feet in width and dipping at approximately 45 degrees from surface to an unknown depth. It may be assumed that it continues well below the lowest depth established to date by diamond drilling. At present, a vertical winze (No. 3 winze) hoists the ore from the 2,360-foot level to the 1,600-foot level, on which it is hauled about 900 feet to No. 3 shaft, also vertical, and there hoisted to the mill bins on surface. To maintain ore reserves at a five-year figure, at full production, additional deep exploration was required immediately. It was decided to sink No. 4 winze, a vertical opening of the same size as the other operating shafts, to provide ten additional levels (17 to 26) at 150-foot intervals, with additional depth to allow for an underground crusher installation and usual loading-pocket facilities for three-ton skip-hoisting. The winze was bottomed at 1,753 feet below the collar, at a depth of 4,117 feet below surface, and is the deepest man-sized opening in Manitoba.

Jan 1, 1949

By Ali Bunjaku, Lauri Pesonen, Hannu Johto

It is well known that there are many ways to process copper concentrates into copper anodes using the pyrometallurgical route. All modern copper smelting technologies are fundamentally energy efficient and environmentally safe options, and therefore choosing one depends on the desired capacity range, feed impurity levels, plant location, flexibility needs, overall energy use, and of course smelter economics in both the short and long term. This paper focuses on comparing different solutions which have potentially the lowest variable opex (operational expense), meaning in practice finding out which technology offers the best chances for profit maximization under certain scenarios. For the comparison, we chose to have a closer look at Outotec Flash Smelting (FSF) – Peirce-Smith Converting (PSC), Outotec Flash Smelting (FSF) – Outotec- Kennecott Flash Converting (FCF), Outotec Ausmelt TSL Smelting (ASF) - Peirce-Smith Converting (PSC), Outotec Ausmelt TSL Smelting (ASF) - Outotec Ausmelt TSL Converting (ACF), Mitsubishi Smelting Process (MIT), Bottom Blowing Reactor (BBR) – Bottom Blowing Continuous Converting (BCC), and Side Blowing Furnace (SBF) - Top Blowing Converting (TBC) since these seem to be the main state-of-art technologies now being applied in many recent copper smelter projects around the world. The work was carried out by modelling each smelting route by using the new HSC SIM 9 simulation software and applying operation time, energy, and consumables consumption numbers for each unit process and stream. Combined with cost data, the exercise produced a rich set of information which will be shown in detail for each area per scenario. The authors’ goal here was to provide a fair comparison where each technology can be evaluated from various perspectives such as electricity use or refractory consumption. INTRODUCTION Copper can be produced either pyrometallurgically or hydrometallurgically. The hydrometallurgical route is used only for a limited amount of the world’s copper production (~20%) and is normally only considered in connection with in-situ leaching of copper ores. On the other hand, most of the copper extraction from Cu-Fe-S minerals is pyrometallurgical (~80%) (Schlesinger 2011, ICSG 2017). Thus, several different processes can be applied for copper production, including the following state-of-the-art technologies: Outotec Flash Smelting (FSF) – Outotec-Kennecott Flash Converting (FCF) Outotec Flash Smelting (FSF) – Peirce-Smith Converting (PSC) Outotec Ausmelt TSL Smelting (ASF) - Peirce-Smith Converting (PSC) Outotec Ausmelt TSL Smelting (ASF) - Outotec Ausmelt TSL Converting (ACF) Mitsubishi Smelting Process (MIT) Bottom Blowing Reactor (BBR) – Bottom Blowing Continuous Converting (BCC) Side Blowing Furnace (SBF) - Top Blowing Converting (TBC)

Jan 1, 2019

By J. J. Denny

IN a preliminary paper (1) it was shown that the addition of small quantities of metallic aluminium powder almost completely inhibited the solubility of siliceous material in the beaker. Six rabbits exposed to quartz dust for six months all showed well developed silicosis. Seven rabbits exposed to quartz dust plus 1 per cent metallic aluminium powder for the same period did not develop silicosis. At that time, we were not in a position to state either the manner in which metallic aluminium reduced the solubility of siliceous material, or, from the animal experiments, whether the aluminium was acting locally or systemically, or for what period after the cessation of dusting it would continue to act. This paper reports the further progress of this investigation. CHEMICAL EXPERIMENTATION The technical details pertaining to the various substances used in the experiments are given in an appendix which is on deposit with the American Documentation Institute, Washington, D.C. For lack of space, it is not printed here. The term 'solubility' is used to indicate the concentration of silica in the solution under the conditions as noted, determined colorimetrically (2), and expressed as parts per million (p.p.m.). The term 'reduction in solubility' indicates the difference between the solubility of the .silica in the presence of the aluminium powder and its solubility in the absence of aluminium powder. It will be noted that the solubility figures for different samples of quartz with no added aluminium vary considerably. The figures do not refer to an equilibrium solubility of silica but to the actual amount of silica dissolved from a given sample in a given time at a given temperature. In view of the fact that quartz dissolves extremely slowly, it is evident that the actual figures in any case will depend upon the surface exposed, i.e., fineness of grinding of the different samples.

Jan 1, 1939

By Pizhi Zhao, Jingwei Zhao, Zhenshan Liu, Yiheng Cao

"A new Al-Mg-Si-Zn alloy designed for automotive outer panel was trial-produced with industrial procedure. The final product shows a strong planar anisotropy. X ray diffraction analysis shows such strong anisotropy is caused by the dominating cube texture component in the final product. The reason for such high cube texture component was investigated by tracing texture evolution starting from the hot roll slab. It is found that certain cube texture components already exists in the hot rolled slab. The density of cube texture component shows as a wavy change through the following1st cold rolling, inter-annealing, 2ndcold rolling and solution treatment. This study shows that the cold rolling in the laboratory can well represent the texture evolution during the industrial production. The results obtained by lab rolling hints that change of second cold rolling reduction has weak effect on the planar anisotropy, when the gauge of hot rolled slab and final sheet are fixed.INTRODUCTIONWith the rapid progress of light-weighting in the automotive industry, aluminum sheets get more and more application as closure panel and structure parts. Recently the dominating alloy for outer panel is 6xxx series, containing the main alloy elements Mg and Si. The popular gradesareAA6016,AA6111, AA6022, and AA6014. These alloys still cannot satisfy the various requirements from automotive manufacturers. Most suppliers of automotive aluminum sheets are developing their own specific grades according to the customer’s demand. To increase the baking response, anew Al-Mg-Si-Zn alloy was designed, concerning the high combination energy between Zn solutes and vacancies formed during the quenching stage of automotive sheet manufacture. This combination is helpful to the precipitation of ß”phase during the paint baking (Wang, 2015,2016; Yan, 2014).The plastic strain ratio (r value)is a key index of the formability of automotive body sheet. A high r value means a good formability. The r values in different directions can be used to evaluate the planar anisotropy of the metal sheets. The trial produced Al-Mg-Si-Zn sheet shows a strong planar anisotropy with respect to r values. Since the r value is tightly related with texture, the texture evolution from hot roll slab (HRS) to final T4P temper was analyzed with X ray diffraction (XRD) to find the reason for the high anisotropy. Besides, the cold rolling reduction (CRR) was varied in the laboratory to modify the texture distribution, i.e., the planar anisotropy."

Jan 1, 2018

By C. A. Pickles, K. Mackowiak, D. Gajonera

"Shake-flask oxidation tests were performed on Red Dog mine waste to study the initial dissolution behaviours of lead, zinc, and iron. The conditions for accelerated acid generation in terms of Eh and pH were determined. Each mineral behaved distinctly, with galena dissolving first, followed by sphalerite, then pyrite, although there was some overlap in behaviour. Iron was not detected in solution until approximately day 40 and was present at low concentrations. The experimental conditions and the theoretical model results indicated the formation of iron oxyhydroxides at low weathering times and jarosite at longer times.RÉSUMÉ Des tests d’oxydation par agitation en flacon ont été effectués sur les déchets miniers de l’exploitation Red Dog afin d’étudier les comportements initiaux de dissolution du plomb, du zinc et du fer. Les conditions entraînant la production accélérée d’acide en termes d’eH (potentiel d’oxydoréduction) et de pH (potentiel d’hydrogène) ont été déterminées. Chaque minerai se comportait différemment ; la galène a été la première à se dissoudre, suivie de la sphalérite, puis de la pyrite, mais un certain chevauchement des comportements a été observé. La présence de fer en solution n’a été détectée qu’après environ 40 jours et ce, à de faibles concentrations. Les conditions expérimentales et les résultats du modèle théorique signalaient la formation d’oxyde-hydroxyde de fer sur de courtes périodes d’altération atmosphérique, et de jarosite sur des périodes plus longues."

Jan 1, 2017

By Chi Zhang, Junyi Wu

"The use of permanent stainless steel cathodes for electrorefining and electrowinning of cathode copper had been introduced to the market long time ago and now is a well-accepted technology worldwide. During the last decades, the Chinese copper refinery industry had been growing rapidly and many large scaled production plants had been built. In the modern refineries, permanent stainless steel cathodes are introduced and used instead of traditional starter sheets. The most common steel grade used is austenitic stainless steel S31603 (316L/1.4404), while both S30403 (304L/1.4404) and N08904 (904L/1.4539) have been used depending on the actual working conditions, especially with regarding corrosion environment. While 316L permanent cathode functions well in many plants, different kind of problems, such corrosion and deformation, have been reported. There is therefore an increased need for more suitable material. New stainless steels, such as duplex stainless steels, with better properties have been tried and introduced into the application of permanent stainless steel cathode with satisfied results. The article introduces first the Chinese copper refinery industry and properties of duplex stainless steel in general, and then describes the development of using permanent duplex stainless steel cathode, including the actual working conditions, production of cathode sheets as well as the experiences of application in details. After more than one year’s usage, the advantages of permanent duplex stainless steel cathodes are clear seen.INTRODUCTIONChina has become a major player in the international copper market, accounting for around 40 percent of global refined copper demand. Despite the slowdown of the Chinese economy, the consumption of copper products will still increase, but with a medium and/or low growth which will be the new situation for the coming years. The average growth rate is expected to be around 5 percent per annual. In the coming Five-Year plan for National Economic and Social Development a number of initiatives will be finalized which will require massive amounts of copper. In 2015, the expected consumption of copper products will be over 9 million metric tons. The main driver of the consumption is the electric power industry which accounts nearly the half of the total consumption; followed by cooling application with 15% and transportation with nearly 10%, see figure 1."

Jan 1, 2016

By J. F. Davis

Pegmatite dykes containing lithium minerals and beryl occur dose to the borders of intrusive masses of granitic rock in the Winnipeg River area of Manitoba. Both vertical and flat-lying dykes are present. Most of the pegmatites consist of zones, containing characteristic mineral assemblages, arranged more or Jess parallel to the borders of the dykes. Five important lithium minerals are present; each occurs in a separate zone, but all the lithium-bearing zones are situated toward the centres of the pegmatites. Spodumene is the most abundant and widespread of the lithium minerals and occurs as small crystals intimately intergrown with quartz. Beryl is not an important constituent of the lithium pegmatites, but when .present, occurs outside the lithium zones, toward the margins of the -dykes. Beryl is most common in dykes containing few or no lithium minerals. The mineral assemblage in the beryl zone of the lithium dykes is the same as that of the beryl dykes. The attitude and internal structure, particularly zoning, of the pegmatite dykes, and the texture and assemblages of the constituent minerals, have an important bearing on exploration, development, and mining of these pegmatites, and on the extraction of various mineral products from them.

Jan 1, 1958

By Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"In natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the content of MoO3 varies from 2% to 10%. As a result, the flotability of seyrigite (scheelite with molybdenum) turns to be weaker. One seyrigite mine, which has been built for 3 years,still could not produce qualified seyrigite concentrate due to the weak flotability of seyrigite (Mo-bearing scheelite) in raw ore. In our experimental research, through adopting new seyrigite collector TA-3 and advanced mineral processing technology, the seyrigite concentrate with a grade of 65.62% WO3 at a recovery of 87.47% was obtained for the raw ore containing 0.19% WO3 and 0.074% Mo. By applying the new technical achievement, for the raw ore containing 0.272% WO3, the seyrigite concentrate assaying 68.03% WO3 with a recovery of 77.56% was obtained in industrial production.INTRODUCTIONIn natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the scheelite is changed to be seyrigite (Ca[(W,Mo)O4]) (Ma, Bian, & Wang, 2013). The content of MoO3 in seyrigite varies from 2% to 10% usually, the content of MoO3 in some of the seyrigite even reaches 34%. The flotability of seyrigite is weak (Zhang, 2007), and the seyrigite is difficult to be recovered by flotation with common collectors and regulators. One scheelite mine in Anhui China, which is a skarn type seyrigite mine, has not produced qualified concentrate yet since 3 years it has been built due to the limit of beneficiation technology. Therefore, it is necessary to conduct research on the collectors with high efficiency and developing advanced processing flow for this kind of ore."

Jan 1, 2016

By Yang Shuxin, Guo Qiliang, He Ping, Lu Lizhi, Yao Rui

"We combined stepwise regression and constrained regression statistical method to obtain the best boundary conditions for the calculation of in-situ stress field in Wushaoling tunnel using finite element method. Our numerical results reveal that: the main geologic factors contributing to the initial background stress are gravity and tectonics; the principal stress values would drop in fault zones; the angle between the maximal horizontal stress and the axis of Wushaoling tunnel is acute; Wushaoling tunnel tends to become stable when this tunnel has 2:1 ratio of the height to its width; the possibility of rock-burst exists under high stress.INTRODUCTIONStress state of engineering region is an important factor affecting the stability of project. Geological disasters in the project area are closely related to their stress environment. Wushaoling tunnel which is 20,050 meters long, lying along Lanzhou-Wuwei segment of Lan-Xin Railway in China, is the key project of Lan-Wu double-track railway. The region surrounding this tunnel is under a high stress environment. Accurate identification of the stress environment of the engineering area and the interaction between geomaterials and geotechnical engineering construction holds significant scientific and practical value for engineering design, construction, and operation.Many scholars explored and discussed the present-day tectonic stress through investigations of tectonic evolution history (Ding, & Lu, 1986), crustal deformation (Zoback, 1992), focal mechanisms (Yang et al., 2003, Xie, Cui, & Zhao, 2004), and so forth. However, the above methods would only provide the approximate direction of the principal stress in a broad region, and could not give the absolute stress values. In-situ stress measurement is one of the primary means to directly gauge the current crustal stress. However, in-situ stress measurement can only be applied in small number limited by measurement conditions."

Jan 1, 2015

By R. Jacobs, R. E. L. Pobe

The Moab Khotsong Metallurgical Complex comprises a gold recovery circuit (Noligwa Gold Plant) and a uranium recovery circuit (South Uranium Plant). The metallurgical complex employs the reverse leach technology for the recovery of uranium; specifically, uranium extraction prior to gold using acid leaching processing. The inherent uranium species in the ore are uraninite, coffinite and brannerite. The slurry that has been subjected to the uranium leach is further subjected to solid-liquid separation to separate the uranium in solution through counter-current decantation and the solids (solids carrying all the gold), which are repulped and returned to the gold plant for gold processing. The uranium leaching process is critical to the uranium playing a pivotal role as a value adding by-product to the gold operation. The benefit of adopting this reverse leach process, for improved gold recovery, is that it exposes gold particles occluded within the uranium matrices and avails them for cyanidation. However, the drive for operational efficiency in uranium extraction must be weighed against the incremental operating cost against the backdrop of depressed spot uranium market prices. Over the years, efforts were directed at maintaining the benefit of extracting uranium to enhance gold recovery and simultaneously, optimizing the operating cost model for the uranium operation to remain relevant to the gold operation. The aim of this paper and the corresponding presentation is to give account of the uranium processing optimization journey embarked on over the years; namely, the operational trade-offs made in the process of ensuring that uranium continues to add value to the gold operation. These challenges were faced while striking a fine balance between processing cost and operational efficiencies against the prevailing depressed uranium spot market prices. Mineralogical- and laboratory tests conducted form the support basis for the results and observations articulated in the paper.

Jan 1, 2020

By Hyumng Sup Choi

The role of the interfacial electrical 'Condition on the adsorption of col-lectors on mineral surfaces has been studied by electrophoretic mobility and adsorption measurements made on zircon. From the investigation of the electrokinetic properties of zircon, H+ and OH-are seen to act as potential determining ions, thus controlling the electrical nature of this mineral. The isoelectric point of zircon occurs at a pH of approximately 5.0, and it is evident, therefore, that the zircon surface would be positively charged below a pH of 5.0 and negatively charged above this pH. The adsorption of collectors therefore de-pends strongly on the pH of the solution; anionic collectors are adsorbed on positively charged surfaces and cationic collectors on negatively charged surfaces. This, in turn, de-fines the effective flotation condition, with respective collectors, for this mineral. The above results have been correlated with the flotation behaviour obtained by the simplified flotation test using a modified Hallimond tube.

Jan 1, 1963

By Ltd. (CYMCO) Technology Center Yunnan Metallurgical Group Co., S. Jian, T. Song, J. D. Miller

"As sulfide zinc ore deposits become exhausted, nonsulfide zinc ore deposits become the other resource for zinc production. However, flotation for zinc recovery from nonsulfide deposits is much more difficult than the flotation of sphalerite from sulfide deposits and may become an option for zinc production only if a suitable processing technology is developed. In this regard, research efforts are being devoted to the flotation of nonsulfide zinc oxide minerals. Some common methods which have been used for the flotation of zinc oxide minerals include sulfidization-flotation, activation, and direct flotation with anionic and cationic collectors. The traditional flotation techniques have low efficiency and difficulty in separation and recovery of the zinc minerals from gangue minerals, for example, smithsonite (ZnCO3) from other carbonate gangue minerals and hemimorphite (Zn4Si2O7 (OH)2·H2O) from silicate gangue minerals. In this study potassium lauryl phosphate was evaluated as a collector for the flotation of nonsulfide zinc minerals. Results from contact angle and microflotation experiments at pH 6–9 show that hemimorphite (Zn4Si2O7 (OH)2·H2O) can be floated from quartz and that smithsonite (ZnCO3) can be floated from calcite. However, when dodecylamine, which is a common collector reported in literature for the flotation of nonsulfide zinc minerals, was used as collector, no significant difference between nonsulfide zinc minerals and gangue minerals was observed at any pH value. Initial evaluation suggests that potassium lauryl phosphate is effective at low concentration and may be a promising collector for zinc oxide mineral flotation.INTRODUCTIONBefore the twentieth century, zinc was mainly produced from nonsulfide ores (Large, 2001; Gilg, Boni, & Cook, 2008). With the development of differential flotation processes in the late 19th century major production switched from nonsulfide zinc sources to sulfide zinc ores (Hitzman, Reynolds, Sangster, Allen, & Carman, 2003; Gilg et al., 2008). However, as it is becoming more difficult to find new sulfide ores, recovery from nonsulfide deposits is being considered. Nonsulfide flotation for zinc recovery is much more difficult than the flotation recovery of sphalerite from sulfide deposits and may become an option for zinc production if a suitable technology is developed. Zinc and lead oxide ores are difficult to beneficiate ores due to their similar floatability with gangue, high solubility in water, and the influence of slimes (Fa, Miller, Tao, & Li, 2005). In order to improve the performance of oxidized minerals, lots of effort is being devoted to this field of study (Ejtemaei & Mahdi, 2014)."

Jan 1, 2016

By M. A. Vasina, I. A. Matveeva, E. A. Naumova, V. V. Doroshenko, N. A. Belov

"Using the calculated (Thermo-Calc software) and experimental methods (SEM, TEM, EMPA, DSC, XRD, etc.) the phase composition, structure and hardening of aluminium alloys of the Al-Ca-Zn-Mg system were studied in the following range: 2. 5%Mg, up to 10% Ca, and up to 14% Zn (wt%). Fragments of this quaternary phase diagram in the aluminium corner were constructed, including the liquidus surface, as well as some vertical sections. It was shown that the relatively large amount of zinc enters in the Ca-containing phase, which formula can be described as (Al,Zn)4Ca. An increase of Zn content leads to formation of Al4Ca primary crystals at lower concentrations of calcium. The eutectic (Al)+(Al,Zn)4Ca has a fine structure and aluminide particles are capable to spheroidization during the heat treatment at temperature 500 C. The maximal level of hardness observed on calcium containing alloys was higher than 200 HV, what gives the reason to expect good strength properties. With an example of an Al-9% Zn-2,5%Mg-3,5% Ca model experimental alloy based on the (Al)+(Al,Zn)4Ca eutectic, a principal possibility of manufacturing thin rolled sheets was demonstrated.INTRODUCTION Aluminum alloyed with calcium was first studied in 1970-80s by such authors as Piatti (1976), Moore (1978, 1980), Il'enko (1985), Swaminathan (1990), and Perez-Prado (1997) as superplastic materials. In particular, the alloy systems Al-Ca-Zn were studied (Il'enko, 1985, Swaminathan, 1990, Perez-Prado, 1997). For some time there was no new published works concerning the aluminum-calcium alloys. During the last years many works were published dedicated to the calcium alloying of magnesium alloys (Kim, 2011; Xu, 2011; Aljarrah, 2008; Bakhsheshi, 2014). This urged the authors (Belov, Naumova & Akopyan, 2016) to start studying cast and wrought aluminum-calcium alloys for construction (2008–2014). There is almost no information in the literature concerning triple and more complex diagrams of the aluminum-based system states with calcium and other elements. In recent work, parts of the state diagrams are plotted for the aluminum angle zone: Al-Ca-Mg-Sc (Belov, Naumova & Bazlova, 2016), Al-Ca-Ni-Sc (Belov, Naumova & Bazlova, 2017), Al-Ca-Si-Sc (Belov, Naumova & Akopyan, 2017) and others. Special attention was paid to the study of the system Al-Ca-Zn-Mg (Naumova, 2017). Based on this system creation of advanced extra-high tensile alloys is planned. Wrought extra-high tensile alloys series 7??? based on the system Al-Zn-Mg-Cu are well studied."

Jan 1, 2018

By D. Milne, G. Snell

"A new method to predict stope hangingwall failure in underground excavations is proposed. This method compares movement rate for stope hangingwalls, determined from changes in strain or deformation, with changing opening geometry. This geometry is represented by the effective radius factor (ERF), a measure of relative distance to supporting abutments from an opening surface point. This strain-ERF (SERF) approach is applied to an instrumentation program for Brunswick mine near Bathurst, New Brunswick. The SERF method for this case study predicted failure at an ERF of 13.9 m and hangingwall failure actually occurred at an approximate ERF of 12.4 m.RÉSUMÉ Cet article propose une nouvelle méthode permettant de prévoir la rupture de l’éponte supérieure des chambres d’abattage dans les excavations souterraines. Cette méthode compare la vitesse de mouvement des épontes supérieures des chambres d’abattage, déterminée à partir des changements aux niveaux des contraintes ou de la déformation, à la géométrie variable de l’ouverture au jour. Cette géométrie est représentée par le facteur du rayon effectif (ERF, de l’anglais Effective Radius Factor), une mesure de la distance relative jusqu’aux appuis latéraux de soutènement à partir d’un point de la surface d’ouverture au jour. Cette approche contraintes-ERF (SERF, de l’anglais strain-ERF) est appliquée à un programme d’instrumentation pour la mine Brunswick située près de Bathurst, dans le Nouveau-Brunswick. Pour cette étude de cas, la méthode SERF prévoyait une rupture à un ERF de 13,9 mètres (m); la rupture de l’éponte supérieure s’est effectivement produite à un ERF d’environ 12,4 m.INTRODUCTIONUnderground stope design can be improved with the installation of field instrumentation. The most commonly used instrumentation for monitoring rock mass behaviour around open stopes is extensometers. The y-axis of Figure 1 represents how the changing rate of movement, measured using either displacement- or stress-type instruments, can be observed over time. The magnitude of movement measured by extensometers can give an approximation of the load on installed support (Milne, Pakalnis, & Lunder, 1996) and a changing rate of movement can indicate approaching instability."

Jan 1, 2018