Search Documents

By D. Sagara, V. G. Makhado

"A model based control strategy was implemented at Loulo Gold Mine in Mali, to stabilise the thickener underflow stream density. This stream acts as the feed to the leaching circuit. pH control of the leaching circuit was integrated with the model-based controller due to slow process dynamics that are not suited to PID control. The controller performance was quantified over a period of 6 months, and was compared to the performance before implementation. The model based controller reduced process variability for both thickener underflow density and pH considerably, and resulted in a reduction in flocculant and lime consumption of 9.32 and 6.55%, respectively. INTRODUCTION Reagent consumption in gold processing plants significantly contributes to the total operational costs. In a typical Carbon-in-pulp (CIP) circuit, the reagent consumption associated with leaching, adsorption, elution and regeneration contribute to approximately 15% of the total operational costs (Stange, 1999). At Loulo Gold Mine, the reagent consumption associated with leaching, adsorption, elution and regeneration contributes to 6% of the total operational costs. As such, a reduction in reagent consumption will present a significant opportunity for savings on operating expenditure. Variability in feed ore characteristics results in continuous changes in steady state operating regions, which presents process control challenges as a result of the long residence times in some of the process units associated with gold processing plants. Overdosing often occurs in the presence of process variability to ensure safe operation and to maintain recovery targets. As a means of reducing reagent consumption and accounting for significant changes in the feed to gold plants, some of the plants have resorted to improving their process control strategies around their circuits. This paper focuses on the implementation of a model predictive based controller at Loulo Gold Mine on their thickener and Carbon-in-leach (CIL) tank to: •,stabilise the thickener underflow density, and •,the CIL tank pH."

Jan 1, 2017

By W. E. Cockfield

This paper is not intended as an original contribution to this subject, but rather as a review of the main theories which are held with regard to placer deposits, with, of course, particular reference to the placers of British Columbia. The present interest in gold mining has, however, brought the subject of placers to the fore, and possibly a brief outline of the geology of such deposits will serve as a basis for discussion on the subject. In Canada, the most valuable of our placers are deposits of gold, and consequently the discussion will centre largely on placer-gold deposits. The same principles apply, of course, to placer deposits of other metals. The Origin of Placer Deposits As a starting point, the idea which is prevailingly held is that placer or alluvial gold is detrital in origin, that is to say, the gold originally existed in veins, lodes, or disseminations in the country rock of the regions in which the placer deposits are now found, and that, through the various erosive forces of nature, it was liberated from those veins or lodes and concentrated in the form in which we now find it. 1 have not time to go thoroughly into the proof of this, but the lines of evidence are many. If we take the Cariboo district as a typical example, Johnston and Uglow(l) have shown, first of all, that the placer and vein gold are identical in character. Crystals occur both in the placers and in the lodes, but the crystals in the placers are nearly always slightly worn, indicating transportation.

Jan 1, 1932

By Q. G. Reynolds, R. T. Jones

"Residence time distributions are well defined for batch and continuously stirred reactors. However, there exist many smelting furnaces that do not fit either of these classifications. A mathematical description is presented for the case of a furnace that is fed continuously, but where the liquid slag and metallic products are tapped intermittently. The effects of slag and metal tapping intervals and the fraction of liquid retained in the furnace, are shown to have a significant effect on the residence time distribution.INTRODUCTIONThere are some processes in which the time spent by the feed material in a smelting furnace plays a significant role in determining the extent of the reactions between metal and slag and influences the degree of settling of metal droplets from a molten slag.Residence time distributions are well defined for batch and continuously stirred reactors. However, there exist many smelting furnaces that do not fit either of these classifications. Here we will focus on producing a mathematical description for the case of a furnace that is fed continuously, but where the liquid slag and metallic products are tapped intermittently. The effects of slag and metal tapping intervals and the fraction of liquid retained in the furnace, are studied.Previous work (Jones, la Grange and Assis, 1997) has studied the effect of retention time on the degree of cobalt recovery achieved in a slag reduction process. In that work, a method was proposed for the calculation of the mean residence time of the contents of a pilot-plant furnace. That approach is to be extended here for the purposes of providing a more general design or scale-up tool.The maximum allowable depth of molten material in a given furnace is affected by such factors as the desired batch size (or the size of the ladles) and the pressure of the molten material that the tap-hole and surrounding system can withstand. Within these constraints, there might be some scope for choice of taphole position. The effects of this choice need to be understood mathematically."

Jan 1, 2012

By A. Chamanara

The gross vehicle weight (GVW) of an ultra-class mining truck comprises the unsuspended weight below the struts plus the suspended empty vehicle weight, plus the payload. Theoretically, one third of the suspended total weight is supported by two front struts and two thirds by two rear struts. However, since the payload position is not fixed when placed in the truck body and varies from load to load, compounded by uneven haul road profiles, the truck structure experiences higher than normal stresses, which manifest in the reduction of the life of the truck via structural fatigue. The downstream effects are a decrease in production and increase in operational and maintenance costs. In order to control the dynamic forces causing the high stresses on the truck structure, both the haul road conditions and the load distribution in the truck body need to be investigated. The latter aspect is the prime focus of this paper. A field test has been conducted in an oil sands mine where the Caterpillar 797B trucks are loaded by a Bucyrus 495 shovel. The strut pressure readings are collected using the data-loggers on the trucks as well as the truck velocity associated with each reading. Rack, roll and pitch are the main key performance indicators (KPIs) that are calculated to study the adverse effect of an unbalanced payload and consequently the truck structure. Finally, the shovel bucket load passes within the truck body are simulated and a new method is suggested to improve the truck payload balance.

Aug 1, 2013

By I. Colquhoun

Current practice tends towards "integrity as an afterthought". That is, integrity is treated as an isolated aspect of operations and maintenance. In fact, this works quite well. But it would work so much better and with less uncertainty if integrity management measures were introduced at the design phase and addressed the entire life-cycle of the pipeline asset. The talk will address the measures and metrics that can be implemented on a new pipeline during design to optimize integrity and deliver a comprehensive operating manual and integrity management program for the pipeline system. This deliverable should describe the risks to be assessed and monitored, and the actions to be taken to control these risk adequately. Properly executed, integrity by design will provide a good working estimate of the life-cycle integrity management costs and maximize system reliability.

Jan 1, 2005

By Phillip Mackey, Elmira Moosavi-Khoonsari

L'industrie du cuivre traverse une période passionnante, marquée par une forte demande, de bons prix et l'ouverture de nouvelles grandes installations. L'année 2022 a battu des records de production de cuivre, ce qui laisse entrevoir un potentiel de croissance supplémentaire. De grands projets sont en cours, comme la technologie Double Flash à Manyar, en Indonésie, qui peut produire plus de 500 000 tonnes de cuivre par an. À Munda, en Inde, on a construit la plus grande usine de cuivre du monde, qui produit plus de 1 000 000 tonnes de cuivre par an en combinant deux phases. De plus, l’installation de cellules de flottation de dernière génération au Mexique, au Chili et dans d'autres pays témoignent de la volonté de l'entreprise d'utiliser les technologies les plus récentes [1]. L'importance du cuivre dans la transition énergétique est évidente, l'accent étant mis à la fois sur la croissance et sur la protection de l'environnement. Cela se traduit par le développement d'usines de premier ordre dédiées aux pratiques durables.

May 2, 2024

By Chester J. Kuryliw

"The Geology of the Cochenour Willans mine, Red Lake district, was described by J. P. Nowlan in the Jubilee Volume. The complexity and intense alteration of the rocks obscured any clear relationship between ore and structure, and Nowlan recognized that future work might greatly modify the ideas then existing. This has proved to be the case. Subsequent detailed work has established the stratigraphic sequence in the Keewatin formations which are the host rocks of the orebodies, and has shown that the principal orebodies are confined to two adjoining bands of tuff.On this basis, it is now possible to map the complex structures with greatly increased accuracy. The amount of drilling and underground exploration required to find new ore has been much reduced, and indicated ore reserves are now substantially greater than at any time in the past. Daily production in 1955 averaged 187 tons per day at 0.578 ounces of gold per ton.The sequence of Precambrian events in the mine area is summarized in the following table:Intrusion of post-ore dykes.Ore formation.Intrusion of post-faulting, pre-ore dykes.Deformation: folding and shearing; alteration; faulting.Timiskaming sedimentation.Unconformity.Keewatin: volcanics and sediments, host rocks of the orebodies, described in detail in the next section.KeewatinFrom oldest to youngest, the Keewatin rocks in the mine area can be divided into six formations, which have been given local names:“Grey"" LavaA fine-grained dacitic to andesitic lava, amygdaloidal and locally containing well formed pillows. Certain areas are sheared and chloritized to a degree that makes identification difficult. The rocks are carbonatized throughout; the most persistent carbonate veins parallel the upper contact. Thickness more than 1,000 feet. (Minor mineralization, type 1 I -See section on Ore Formation)."

Jan 1, 1949

By J. M. Rios

Without conscious effort and understanding, a number of factors peculiar to mineral exploration campaigns conspire against building sustainability in host communities. These include the episodic and transitory presence of an exploration team in the community and the inherent uncertainty of outcomes; most projects fail. Given these circumstances, there is a strong tendency to apply a simple formula of providing employment, pragmatic philanthropy and supporting infrastructure improvements (roads, schools and clinics) to demonstrate that mining provides benefits. Experience in rural native communities of Mesoamerica has shown that it is possible to create positive, sustainable outcomes quite rapidly within communities, which build capacity, improve quality of life and support a strong social license to operate. Success comes from an understanding of community structure and dynamics; engaging with all segments of the community; creating healthy, transparent and accountable relationships based on clearly defined roles and responsibilities; and supporting and strengthening the role of women in a culturally appropriate way. To this are added innovative and culturally appropriate ways of incorporating sustainability through genuine social investment in areas more typically addressed by exploration companies; health, education, and environmental management.

Aug 1, 2013

By H. Deveci, E. Y. Yazici, A. D. Bas

The leach solutions of waste of printed circuit boards (WPCB) may contain a wide range of base and precious metals with different concentrations due to heterogeneity of these wastes in composition. Therefore, selection of a suitable metal recovery method is of practical importance for downstream processing of pregnant leach solutions of WPCB. Sulphuric acid leaching of WPCB in the presence of a suitable oxidant is capable of dissolving base metals as well as precious metals such as silver. In this study, cementation of silver from sulphuric acid leach solutions of WPCB using metallic copper, aluminum and zinc was studied. The WPCB sample was assayed to have a silver content of 694 g/t. A synthetic leach solution containing 20 mg/L Ag in sulphuric acid solution (0.51 M H2SO4) was prepared based on the silver concentration in pregnant leach solutions of oxidative sulphuric acid leaching tests. Total sulphate concentration ([SO4 2-]T) was kept constant using sodium sulphate at 1 M. Metallic powders of copper (-850 +600 µm), aluminum (-425 +45 µm) and zinc (-45 µm) were used in the cementation tests. The effects of metal type (Cu, Al or Zn), dosage of metal powders (above the stoichiometric ratio by up to 2000-fold) and temperature (20-80°C) on the rate and extent of silver extraction from the solution was investigated. The effect of presence of copper on the cementation performance was also tested. Under suitable conditions high silver recoveries (>90%) was achieved using metallic copper and zinc while aluminum yielded the lowest silver recovery (i.e. 40% Ag). The kinetics of cementation by zinc was comparatively higher than that of other metals. Increasing the temperature was observed to significantly enhance both the rate and extent of silver cementation. SEM-EDS studies were performed to characterise the metallic powders after cementation.

Jan 1, 2016

By A. Aubin, H. Yang, G. Zaluski

The Athabasca Basin of northern Saskatchewan and Alberta is an exceptionally rich metallogenic region, hosting more than 2.8 B lb U3O8, of which over 927 M lb U3O8 have been mined out since extraction first started in the late 1970’s. A detailed compilation of several empirical features of 85 deposits located within the basin was conducted in order to understand the distribution and variability of the geological characteristics of the mineralization and its associated alteration. A new empirical classification was devised based on four parameters: 1) geometry of the mineralization (dimensions and relation to the unconformity surface), 2) size, grade and metallurgical complexity of the mineralization, 3) lithostructural setting, and 4) extent and nature of associated alteration haloes. This compilation defines the footprint characteristics of the Athabasca Basin deposits, which guides decision-making processes from early exploration and discovery to resource expansion and extraction.

Jan 1, 2020

By D. F. Scott

"DEFINITION OF THE REGION AND ITS BOUNDARIESTHE REGION of Western Canada covered by this re-port lies between the Precambrian rocks of the Canadian Shield and the structurally deformed rocks of the eastern Cordillera, extending northward from the international border to the 60th parallel. It is some 487,000 square miles in area, with a total sedimentary fill of about 535,000 cubic miles0>. It includes parts of the prairie provinces of Manitoba, Saskatchewan and Alberta and the northeast corner of British Columbia and forms part of the geological region known as the Interior Platform, commonly referred to as the Western Canada Sedimentary Basin. The bedrock comprises carbonates and evaporites of Paleozoic age that lie on Precambrian crystalline rocks and are over-lain by a relatively thick blanket of Mesozoic and Tertiary elastic rocks. The nearly flat-lying bedrock, covered by a thick mantle of glacial drift, forms the Interior Plains physiographic province."

Jan 1, 1970

By T. Newton, G. A. Bezuidenhout, P. J. Tauetsile, F. Trask

The technology to selectively leach gold, silver and base metals from ores, concentrates, and wastes, using an alkaline glycine solution, has initiated significant interest in using the new technology in various environments such as in-situ, in-place, dump, heap, and vat and agitated tank leaching. It has been shown that glycine acts synergistically with a number of other lixiviants to lower the net consumption of the other lixiviants while allowing low cost glycine solution recovery. Glycine is a non-toxic, stable, environmentally benign reagent that is available in bulk industrial quantities. It has the ability to dissolve most copper oxide and sulfide minerals, as well as native copper, whilst not interacting with acid consuming gangue nor dissolving iron and various or ubiquitous gangue elements. It acts synergistically with small amounts of cyanide to leach gold-copper ores at leach rates higher than either glycine or cyanide on their own, while significantly reducing cyanide consumption and eliminating detoxification requirements. The leaching behaviour of various glycine based systems will be reviewed, followed by the evaluation of the adsorption of gold onto activated carbon. Where the economics merit it, copper can be easily recovered using solvent extraction or sulfide precipitation.

Jan 1, 2017

By Long Han, Beijing General Research Institute of Mining and Metallurgy, Yu Xie, Yunhai Zhang, Yangge Zhu, University of Science and Technology Beijing, Yanbo Shang, Xingrong Zhang

"The first-principles method was employed to study the adsorption of hydroxyl calcium (CaOH+) and hydroxyl (OH-) on hematite and quartz surfaces. The calculation results suggested that OH- preferred to interact with the active Fe sites on the hematite surface, whereas OH- adsorbed on the quartz surface by weak hydrogen bond. Though CaOH+ could easily adsorb on the hematite and quartz surfaces by the formation of Ca-O bond, the covalence formed on the quartz surface was apparently stronger than that on the hematite surface, meaning a stronger and more stable adsorption. CaOH+ adsorbed on quartz surface was mainly through the interaction of O-2p and Ca-3d states, and this interaction on hematite surface was weaker.INTRODUCTIONIron Increase and Silicon Reduction Technology (Yu & Duan, 2002) of hematite is mainly through the reverse flotation (silica is floated away from the iron concentrate). There are two ways to achieve this (Houot, 1983). One is to collect quartz by cationic collector directly; the other is to activate quartz by lime and then collect it by anionic collector. There are two main different views with respect to the mechanism of quartz activation: mono-hydroxyl compound theory (Fuerstenau, Rice & Somasundaran, 1965; Fuerstenau & Palmer, 1976) and surface hydroxyl precipitation theory (Hu & Wang, 1988; Wang & Hu, 1990). The former indicated the formation of the mono-hydroxyl complex is one of the two criteria of quartz flotation. The later theory, on the other hand, suggested that surface precipitation is the adsorption of active species of metallic ion on quartz surface. However, most of those researches are based on the solution chemistry of flotation and little is done at the microscopic level.In this paper, by the help of first-principles calculations, the adsorption models, bonding conditions, Mulliken charge populations and adsorption energies of hydroxyl and calcium hydroxyl ions (OH- and CaOH+) on hematite (001) and quartz (100) surfaces were investigated to find out the lime activation of quartz at atomic level, which is significant for the researches of quartz activation theoretically and practically."

Jan 1, 2016

By W M. Cameron

Geophysical studies have extended seaward in recent years, and the important discoveries which have been made have led to a better understanding of geological processes. A present source of certain minerals, the sea will eventually serve as an important source of desalinated water. The continental helves, in particular, represent a potential mineral resource. The expansion of Canadian oceanographic effort that is now underway will eventually lead to the exploitation of the wealth beneath the sea. THE subject of this symposium, which emphasizes the word "geophysics," the specialties of the speakers who are contributing and the nature of the audience at first made me believe that I, a a physical oceanographer, would be out of place. However, I shall undertake to classify myself as a geophysicist, and shall arrange my remarks on my specialty o that they might be of interest to those of you who are predominantly geologists, metallurgists or mining engineers.

Jan 1, 1963

By M. Gagné, F. E. Goodwin

The mining industry represents a significant investment in infrastructure of which steel plays a key role. Many structures in a mine are made of steel including shaft structures (buntons, station steelwork and headgear); stope structures (roof supports, pipe hangers); haulageway structures (ore transfer stations, electrical stubbies); and surface structures (plant buildings, tank supports, pipe gantries, conveyor belts, stacks, stockpile structures, stairways and railings). Maintenance of structural components can often be difficult because of the environment, including those where corrosive fumes persist, or limited access, such as in shafts where access is limited, or to short maintenance shifts or where limited working space is available. Thus a cost-efficient, long-lasting and maintenance-free protection system for steel should be specified. Galvanizing provides the required high-quality, long-term corrosion protection to steel. Galvanizing provides protection in two ways, first as a physical barrier to corrosion and secondly by means of cathodic or sacrificial protection that is unique to zinc. The dual nature of corrosion protection provided by galvanizing significantly extends the service life of steel even in the most challenging environments. The unique corrosion protection properties provided by galvanized steel will be highlighted with global mining application case studies.

Jan 1, 2015

By G. Paillard, I. E. Puddington, A. F. Sirianni, F. W. Meadus

Experiments with some selected Nova Scotia coals and a single sample of American anthracite, reconstituted in granular form with lower sulphur and ash contents by spherical agglomeration methods, are described. The effect of different bridging liquids, grinding times, gangue depressents and modes of agitation on the final product are discussed. The application of agglomeration techniques as a means of drying wet coal fines is also noted.

Jan 1, 1968

By S. J. Cook

The system of mining statistics for Canada, as it exists today, represents the result of long years of progress, first by the Geological Survey, later and more comprehensively by the Mines Branch of the Department of Mines, and now by the Mining Branch of the Dominion Bureau of Statistics-all supplemented by the very comprehensive reports published by the several provincial departments of mines. It is the purpose of this paper briefly to state the development and present status of Canada's statistical service, more particularly in regard to information on mineral production, and to show that in its evolution continuous progress has been made in the elimination of factors tending to duplication and overlaping, with the result that the construction of an adequate statistical service has been carried out with the least possible expenditure of .public funds. For the purpose of this discussion, the subject of mineral statistics may conveniently be considered from two points of view. The technical difficulties in obtaining satisfactory and complete data from the variety of industries represented in the mining fields of Canada must be apparent to all. Methods of record-keeping are almost as numerous as mines and even the larger concerns which maintain elaborate records for their own information, often find it difficult to compile the statistical reports required of them, because the specific form of inquiry differs from the method in use in their offices.

Jan 1, 1924

By S. Koski, J. Vanderbeek, J. Enriquez

"The Cerro Verde copper-molybdenum porphyry mine, majority owned and operated by Freeport- McMoRan Copper & Gold, is located 30 km southwest of Arequipa Peru. The concentrator, which produces copper and molybdenum concentrates, started operating in late 2006 with a 108,000 tpd design capacity, processing primary sulfide ore (mainly chalcopyrite and molybdenite). Plant capacity was recently increased to 120,000 tpd. The comminution circuit consists of one 60” x 113"" primary crusher, four MP-1000 secondary crushers in closed circuit with dry screens, four 2.4m x 1.6m High Pressure Grinding Rolls (HPGRs) in closed circuit with wet screens, and four 7.3m x 11m gearless ball mills in closed circuit with cyclones. The HPGR circuit is fed by the Secondary Crushing circuit product at a T80 of 35 millimeters, and the HPGR circuit product feeds the Ball Mill circuit at a T80 of 3000 microns.This paper describes operating experiences with HPGRs during these first four years highlighting improvements in operating practices and presentation of data regarding operational efficiencies, also discussed are the primary benefits provided by HPGRs such as production of micro fractured particles, reduced ore Bond Work Index, and reduced power consumption. Cerro Verde represents the first installation of HPGRs in both the copper industry and large scale hard rock mining."

Jan 1, 2012

By W. H. Zieman

NORMAN WEISS, Milling Engineer, American Smelting• and Refining Company: The subject of the Forum on Rod and Ball Mill Liners is very fascinating, and there is no end of discussion when operators get together on grinding. However, the hypotheses and suppositions easily outrun the facts, especially when we •consider the inaccuracy of many reported observations. Still surprisingly small is the number of concentrators even reasonably well equipped to measure power consumption of each grinding mill, together with running time, so that data on this tangible factor, at least, can be obtained with precision. While the more elaborate devices of this nature, producing for each 24-hour period the total power consumption, average kilowatt hours per hour, short-term demand chart, instantaneous demand, and print-out, may cost in the neighbourhood of $2,500 per mill and may be difficult to justify, the combination of an ammeter, watthour meter, and running-time meter will cost only a few hundred dollars, so there appears to be little reason not to in-stall them in view of their numerous advantages.

Jan 1, 1959

By J. Gray, J. Peck

As the turn of the century approaches, traditional open pit mining methodologies and processes are being modified through the introduction and use of new technologies. As in other industries, the personal computer is dramatically changing the traditionally conservative mining industry by allowing mines of varying size and capacity to increase their productivity and efficiency through the use of easy to use, office software. Computer-based monitoring and control systems are also being used more frequently to measure and optimize, in real-time, the performances of operating equipment. When communicated to an end-user, this information can provide accurate and timely answers to questions of how much, where, when, and by whom. This capability forms the foundation of a more comprehensive, proactive management and planning facility where, ultimately, information acquired from the producing equipment will be used to optimize and control machine and human activities. As these technologies mature and become essential tools in a mine, they will eventually serve as the basis for more robotic and autonomous mining operations.

Jan 1, 1999