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By Virginia Lawson, Adam Price

The rougher flotation stage is used to reject liberated gangue at a coarse size. Base and precious metals due to their high specific gravity tend to recycle in the grinding circuit and report to the flotation circuit at a finer size than the gangue from which it is being separated. Generally liberation levels of greater than 50% are achieved in roughing and thus a portion of the feed can be immediately upgraded to final concentrate. The proportion increasing as the amount of liberated mineral in the feed increases. Scalping out concentrate from the rougher can reduce the size of the subsequent regrind and cleaner circuits. Examples of alternative process design for circuits demonstrates that you don’t need large volumes to effectively recover all of the minerals – you need smart flotation. Several case studies will be presented where circuits can be significantly reduced in size by designing smarter – not larger. This paper describes case studies to test the amenability of the Jameson Cell to produce final concentrate from rougher feed. Metallurgical performance and plant design implications are discussed. Froth flotation has been used extensively for mineral concentration for over 100 years. Although the flotation cell design has changed, it has generally simply increased in capacity rather than increase in efficiency. Cell capacities of over 600 m3 are now being used in rougher flotation particularly for the lower grade ores where the amount of surface area for flotation is deemed less significant than the required volume. The plant design volume in rougher flotation comes from laboratory batch flotation tests and/or pilot plants. The volume required for the plant is calculated based on the laboratory residence time multiplied by a scale- up factor. Examples of laboratory to plant scale-up design are given in Dunne et al. (2010 part 2). The factors are usually between 2 and 3. A laboratory residence time of 10 minutes would equate to a plant design residence time of 25 minutes using a 2.5 factor. The volume of the required flotation cells can then be calculated using the design tonnage and volumetric throughput. This scale-up factor takes into account the differences in performance between batch flotation efficiency and full scale plant. The differences are likely related to inefficiencies of bubble particle contact in large cells as well as froth recovery, which is essentially complete in a batch cell. Flotation cells, such as the Jameson Cells, are smarter designs that improve bubble/particle collection, bubble/pulp separation efficiency and operate with high froth recovery rather than simply getting bigger. The Jameson Cell was designed on the principal of improving the collection efficiency of fine particles by separating the contact zone from the separation zone and having the bubbles generated by the plunging jet shearing and entraining air. This means the method of bubble generation is not impacted by the wear of mechanical equipment as it the case in other flotation devices. Jameson Cells make bubbles less than 600 micron in size under most operating conditions (Ding, 2016).

Jan 1, 2019

Agenda 1.Energy consumption and energy costs ?focus and failings 2.Energy efficiency methodologies, people and supporting tools 3.Energy cost saving case studies from three minerals processing plants 4.The operations team and the supporting role of Operations IT 5.Conclusion: Reducing energy consumption and energy costs There are many good Energy Efficiency Methodologies ?Energy and GHG Emissions, Management Guidance Document, The Mining Association of Canada ?Energy Savings Toolbox ?An Energy Audit Manual and Tool, Canadian Industry Program for Energy Conservation (CIPEC) ?Lean and Energy Toolkit, Achieving Process Excellence Using Less Energy, www.epa.gov/lean ?Energy Efficiency Opportunities Assessment Handbook, www.energyefficiencyopportunities.gov.au

May 1, 2010

By D. Zagidulin

Short term electrodeposition experiments (up to 80 min.) at two current densities 220 and 275 A/m2 with varying concentrations of thiourea and glue were performed to determine the optimum levels of glue, thiourea and current density for industrial copper electrorefining. White Light Interference Microscopy was used to acquire digital images of the morphology of the electrodeposited copper. Scaling analysis was employed to pa-rameterize the morphological information encoded in the images. The limiting rough¬ness, *, the critical scaling length, Lc, and the aspect ratio, 4*/ Lc, were determined as a function of the deposition time and the amount of organic additives. These parameters were used to calculate the dynamic exponent, B, the roughness exponent, 1/z, and the as¬pect ratio exponent, y, plotted as a function of glue and thiourea concentrations. These 3D plots allowed us to find conditions corresponding to the minimum of B and y, at which the deposited copper is characterized by a small roughness and a dense structure.

Jan 1, 2007

By M. Rudolph, T. Leißner, TU Bergakademie Freiberg, C. Mämpel, R. Möckel, M. Embrechts, T. Leistner

Tin-mining activities have taken place in the region of the German Erzgebirge (Ore Mountains) for over hundreds of years up until 1991. For long times, gravity separation processes used to be the dominating beneficiation approach in those mining districts to recover cassiterite, the main tin-bearing mineral. For fine (< 100 µm) and very fine (< 20 µm) particles these approaches might not represent effective techniques, significant valuable materials could not be recovered and reported to tailings, where it was subsequently disposed. Thus, there are substantial amounts of cassiterite still present in these tailings disposals, most of it as very fine particles with already high degrees of liberation. That fact brings these tailings disposals into focus for potential reprocessing using beneficiation approaches, which are more sensitive to fine and very fine particles. In this paper we present results concerning the laboratory-scale treatment of material from exemplary heaps of the former Altenberg and Ehrenfriedersdorf mining sites using various flotation methods (including conventional froth flotation and oil-assisted flotation). Different size ranges of the material were previously prepared in order to investigate their response to the different techniques. For the study, special emphasis is put on agglomeration flotation, an oil-assisted flotation method. Therefore, an aliphatic oil phase of alkane basis is used to either selectively aggregate or collect the cassiterite particles. Recovery and flotation performance results are presented with respect to different process parameters: various collectors (including sulphosuccinamates and phosphonic acids) and depressants (including sodium fluorosilicate and oxalic acid) regime, oil dosage, agitation time and pulp density during oil/pulp agitation. Furthermore, the oil/particle aggregation behavior is analyzed via particle image analysis and, additionally, collector adsorption characteristics are investigated by contact angle measurements and zeta potential analysis. The data obtained is correlated with the testwork results achieved in order to interpret the flotation response of very fine cassiterite particles.

Jan 1, 2016

Induced microseismicity monitoring is: ?Essential tool in improving the geotechnical understanding about a mine and its inaccessible surrounding rock masses. It helps to determine: -Event timing, location, and magnitude - identification of highly stressed areas -Event source mechanism - the physics of fracturing in its seismic source region -Seismic strain-rate distribution in 5D - identification of stress concentration or migration patterns -Geomechanical interpretation - identification of hidden geological structures or weaknesses in the ground -Strategy for mining e.g. by a block caving method - maximization of mine production and to optimize ground support design -Potential of future seismic hazards -Large event re-entry protocol, to improve mine safety ?The norm as part of mine safety maintenance and long-term mine design practices

Aug 1, 2013

By J. E. Dutrizac, R. J. C. MacDonald, J. B. O'Reilly

"Sometime around 3000 B.C., primitive metallurgists working in the mountainous regions of Asia Minor bordering on the Black Sea (Pontus) produced a soft, easily fused metal today known as lead. It appears certain that the first metal was made by reductive smelting of galena, but whether this recovery arose by the accidental inclusion of galena in the stones of a fire hearth or whether it occurred as a consequence of simple pyrometallurgical experiments on a series of interesting ""stones"" will likely never be known with certainty. The properties of galena, high metallic lustre, great density and facile cleavage, must have excited the ancients, and such ""stones"" would have been the object of primitive testing111 - Shortly after the discovery of lead, the ancients found that the controlled oxidation of this metal at elevated temperatures yielded smaller amounts of a more interesting material, silver. Again, it is uncertain if the production of silver by primitive cupellation techniques was the result of a fireside accident or the consequence of a deliberate experiment, but the important fact is that silver was produced shortly after the discovery of lead. The techniques for making lead and silver spread gradually throughout the entire civilized world, likely as a result of both technology diffusion and independent rediscovery. The physical properties of lead could not have been overly attractive to the ancients, but silver was a different matter altogether. The gleaming white lustre and relative immunity to oxidation quickly assigned silver to the precious materials category, a status it still enjoys. In early times, argentiferous galena was inevitably processed only for its silver values; lead was generally an unwanted byproduct and was frequently discarded as litharge (PbO) during the cupellation process. The silver was eagerly sought, however, and resulted in considerable mining activity culminating in the famous Athenian silver mines at Laurium at the southern end of the Athenian peninsula."

Jan 1, 1999

By Robert B. Parsons

"As the 1981 annual reports of Canadian mining companies one by one see the light of day, it becomes clear that softer metal prices and rising costs are the main problems which beset the industry today. These problems are certainly not lightened by that familiar monster lurking in the shadows-taxation! Recent taxation trends in Canada, and the existing tax regimes for the mining industry, continue to be a major bugaboo.This examination by ""Tax Notes"" of the impact of current taxation trends on the mining industry is based on a speech delivered recently by Robert D. Brown, senior tax partner of Price Waterhouse, Canada, to the annual meeting of the American Institute of Mining, Metallurgical and Petroleum Engineers in Dallas.IntroductionThe purpose of this paper is to tell a story-and it is a story with a moral. The first thing to recognize is that, with depressed metal prices and weakening western economies, high taxes, in and of themselves, are not really the cause of the Canadian mining industry&apos;s present doldrums. However, the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what the future holds for mining men in Canada will equally play an important role in the future development of the Canadian industry. Our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high marginal tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself."

Jan 1, 1982

By Dwayne D. Tannant

This paper presents a summary of results from a questionnaire sent to surface mines in western Canada seeking information on haul road design, construction, and maintenance. There has been a marked increase in the size of the trucks used over the last decade with some mines now using trucks with a payload capacity of 360mt. Consequentially, geometrical elements of haul roads, such as width, have been enlarged to accommodate larger trucks. Most haul roads are constructed on the basis of past experience without use of formal design procedures. With the introduction of larger haul trucks, problems related to rolling resistance, deterioration, and maintenance of the haul roads have become more important. This has lead to adoption of more rigorous design methods for roads at some mines, most notably for the oil sand mines operated by Syncrude Canada Ltd. A summary of the evolution of haul road designs implemented at Syncrude Canada Ltd. is presented.

May 1, 2001

By H. Tokuichi, H. Ohta, K. Sato

A physical separation technique of tantalum capacitors from waste print circuit boards is in a development phase in Japan. A tantalum capacitor consists of an exterior coating of resin (epoxy resin) mixed with silica fillers and a sintered tantalum compact, the latter of which is impregnated with manganese dioxide (MnO2). In this study, we developed a process to recover tantalum oxide from tantalum capacitors by roasting, fluidized-bed separation, and hydrometallurgical treatments. Our aim was to recover tantalum oxide with high purity from waste tantalum capacitors. In this process, the exterior resin was selectively decomposed by roasting without oxidation and pulverization of the sintered tantalum compact at a proper temperature. Furthermore, the decomposed resin with silica filler on the surface of the sintered tantalum compact was mostly removed by fluidized-bed separation. The surface of the sintered tantalum compact was cleaned by ultrasonic irradiation in an acid solution to remove the MnO2 paste as well as residual Ag paste and silica filler. The impregnated MnO2 in the sintered tantalum compact was leached as Mn(II) ions using acid solutions via the reducing effect of tantalum metal to recover purified tantalum oxide.

Jan 1, 2014

By Yi Yang, Mark Zoback

"We report laboratory studies of the time-dependent deformation of core samples from four different formations in the Williston Basin - the Lodgepole formation, the Middle and Lower Bakken formations and Three Forks formation. The laboratory tests reveal varying amounts of viscoplastic deformation in response to applied differential stress. The time-dependent deformation is generally greater in rocks with higher clay and organic content, and can be described by a power-law function. Because the magnitude of the creep strain is linearly proportional to the applied differential stress, we can utilize viscoelastic theory and geophysical logs to estimate the degree to which tectonic stress is affected by viscoplastic stress relaxation. We suggest that viscoplastic stress relaxation results in the Upper and Lower Bakken Formations act as frac barriers during hydraulic fracture stimulation in the Middle Bakken, but the Lodgepole and the Three Forks Formations are not frac barriers.INTRODUCTIONHorizontal drilling and multi-stage hydraulic fracturing in shale reservoirs are critical for successful exploitation of ultra-low permeability shale gas, tight gas and shale oil reservoirs. Characterization of the mechanical properties of the reservoir rocks is essential to understanding the behavior of rocks during drilling and completion. Previous laboratory studies have shown that the timedependent deformation in clay-rich shales can be characterized as linear/viscoelastic deformation (Chang et al., 1997; Hagin and Zoback, 2004a, b; Sone and Zoback, 2013b, 2013c). Sone and Zoback (2013c) showed that laboratory measurements of time-dependent deformation in various gas shale reservoir rocks, and demonstrated that the viscoplastic deformation of these rocks can be characterized by a power-law function. They interpreted the results in the framework of linear viscoelastic theory to quantitatively assess the geomechanical effect of viscous time-dependent deformation over engineering and geological time scales. (Sone and Zoback, 2014) further extended the theory and proposed a viscous relaxation model that can be applied to predict the continuous differential stress magnitude using the geophysical logs. They tested the validity of their model by comparing the stress prediction with the occurrence of drilling induced tensile fractures (DITFs) and the vertical hydraulic fracture penetration observed from microseismicity."

Jan 1, 2015

By C. Anderson, H. Huang, P. Miranda, E. Dahlgren, I. Chandra, M. Jeffrey

The latter part of the 20th century saw great advances in the treatment of refractory gold ores coupled with increased reliance on the use of cyanide for gold processing. Now, in many parts of the world, there is social pressure to limit or eliminate the use of cyanide. As well, treatment of some refractory ores or concentrates which have excessive cyanide consumption, gold cyanide pregrobbing or significant sulfide content remain difficult. This paper will outline the history of the development of alkaline sulfide leaching as an ancillary process to nitrogen species catalyzed (NSC) pressure leaching. Electrochemical fundamentals and the applicable thermodynamics of the alkaline sulfide hydrometallurgical system will be outlined. As well, examples of refractory gold recovery with alkaline sulfide hydrometallurgy such as an arsenopyrite gold concentrate application, a chalcopyrite gold concentrate application, a pregrobbing gold ore application, and a cyanide consuming gold ore application will be delineated in this paper.

Jan 1, 2005

By R. D. Livingstone

"THE LETHBRIDGE COAL FIELD lies mainly .to the north and west of the city of Lethbridge. Mining carried on in this area for over eighty years until 1965. Before the building of a railway the coal was carried by bullock wagon to Montana for use in smelting, and for a while by river boat to Medicine Hat for railway use. The single, almost flat, worked seam is designated the ""Galt"" seam and is about 1.5 metres thick. It belongs to the Belly River formation and is under cover of 80 to 180 metres of weakly stratified sediments. A complex system of cross faults adds to the mining difficulties. Close timbering required in the entries and rooms reflected in a high timber cost and lower output per man shift. The coal is High Volatile"" C"" bituminous in rank with maximum gross calorific value of 11,200 Btu per pound and with a well defined cleavage. Roof conditions in the field range from very tender and very heavy on the south end of the field and west of the Oldman River to a more stable character to the north. Relatively speaking, the whole field would earn a rather tender rating and definitely so in relation to many U.S. fields. Floor conditions are characterized by a bentonitic type heaving in the south end of the field west of the Oldman river to a more stable situation in the north, which can tolerate shuttle car operation if kept drained. Water problems are minimal, except paralleling the Oldman River, where the seam dips below the river level. While vigilance is necessary to prevent accumulations of gas, the volume is rather limited. The seam was entered by shafts, except where small mines were located along the Oldman river banks and gained access by drifts. The coal seam was developed by driving either 3 or 4 Face entries 2 1/2 metres (8 ft) wide on 18-metre ( 60-ft) centres. Sets of dual butt entries driven at right angles to the Face entries completed development work. Normally rooms up to 8 metres wide were turned off the butt entries on up to 11 - metre centres. These were worked in groups of three to five, depending on the roof conditions, and normally advanced 60 m (200 ft). In some areas rooms had to be abandoned short of their objectives due to roof pressure, heaving floor and intermittent work."

Jan 1, 1985

By D. Seo, P. Au, X. Husang, D. Nagy

The production of single crystal (SX) turbine blades represents the current stateof- the-art in Ni-based superalloy design. With complex casting processes and alloy composition modifications, SX superalloys exhibit superior high temperature mechanical properties to their polycrystalline counterparts. Stresses and plastic deformation can occur in SX nickel-base superalloy engine components at various stages during their manufacture and use. For examples, stresses are created during initial solidification and also during solid state processing such as shot peening, grit blasting, blending, electrodischarge machining and welding. Stresses may also be created during service due to random events such as foreign object impacts. Subsequent exposure of SX to high temperatures during solution heat treatment and brazing repair can result in recrystallization which has been shown to be detrimental to both creep rupture strength and fatigue performance of the components. It is therefore the objective of this paper to understand the recrystallization behavior of two SX superalloys, PWA 1484 and 1483, subjected to pre-stressing and subsequent heat treatments.

Jan 1, 2006

By Bo-Hyun Kim

Outline ? Strainburst criteria and hypotheses adapted for this study. ? Influence of excavation method on rock mass properties. ? Excavation disturbance factors vs. deformation modulus, etc. ? Estimation of blasting damage zone around excavation. ? Considerations of energy on burst-prone ground. ? Literature review & closed form solution. ? Numerical simulations. ? Summary and future works.

Oct 1, 2010

By Kyle Paulsen

The Cameco Key Lake mill began processing U-bearing waste rock from the McArthur River mine in 2000. This ore often contains elevated levels of calcium (>4% by mass), resulting in less than favourable conditions in parts of the Key Lake mill, yet still contains U3O8 at a concentration of about 0.3%. To recover the U3O8 and reject as much calcium as possible, modifications were made to the grinding circuit in late 2007 to include a gravity concentrator. The concentrator allows this mineralized waste to be processed separate from the regular blend material, rejecting calcium and concentrating U3O8, thus improving the operating conditions in areas such as SX. This will be presented in greater detail along with results and further work.

Aug 1, 2010

By Al Holmes

"In a recent survey of Canadian work values, 89% of the men surveyed and 97% of the women surveyed described the work in a mine as ""not at all auraetive"", Work in a mine, in fact, was rated by both sexes as the least attractive of all of the types of work surveyed. Confronted with this prevailing attitude, Canada&apos;s mining industry starts out with two strikes against it in its bid to attract and hold on to its fair share of available work force.Behavioural scientists have, for decades, been seeking answers to the questions:• ""Why do people work?""• ""Why do people choose a particular occupation?""• ""Why do people choose a particular organization?""• ""Why do people leave one organization for another?""• ""Why do some people stay in an organization?""• ""Why do some people work harder than others?""Their answers to these questions, although tentative and often contradictory, are being used by more and more organizations to solve people problems. Few industries can afford to ignore them, least of all, perhaps, the mining industry.Consider the following developments:I. General Motors and the United Auto Workers turn around the car assembly plant in Tarrytown, New York in seven years from the plant with the poorest labour relations and production record to one of the best under a program referred to as ""improving the quality of work life.""2. Shell Canada and the Oil, Chemical and Atomic Workers have designed a new petro-chemical processing plant in Sarnia using a set of principles that seek to optimize both the social and the technical system."

Jan 1, 1980

By Vincent H. Hartung

The process of estimating tailings deposition for a given basin is a relatively tedious process without dedicated software tools. The amount of time required to generate a tailings surface for a given set of conditions tends to limit the number of design alternatives that can be considered for a particular project. Recent innovations in the Surpac Vision mining software include the widely used scripting language TCL (Tool Command Language) that brings with it the ability for non-programmers to extend the software functionality beyond mining applications alone. A software tool was developed using the Surpac Vision scripting language to take advantage of 3D visualization and create a flexible tailings modeling solution. The result is an application that removes much of the drafting overhead required to produce a tailings surface. It provides the means for reviewing alternatives and performing sensitivity analysis with variables such as pond elevation, dam or spigot location and height without a significant increase in overall time for a project.

May 1, 2001

By Hooman Askari-Nasab

Open pit mine plans define the complex strategy of displacement of ore and waste over the mine life. The objective of the mine plan is to maximize the future cash flows within the technical and physical constraints. Various mixed integer linear programming (MILP) formulations have been used for production scheduling of open pit mines. In the MILP formulation the slope constraints guarantee that all the overlying blocks are mined prior to mining a given block. Traditionally, the slope constraints have been modeled with cone templates representing the required wall slopes of the open pit mine. The overall pit slopes constructed by these templates are a function of the width and height of the geological block model. Therefore, the overall slopes are fixed in one bearing. This paper presents a general MILP model for open pit mine scheduling with variable slopes constraints. The methodology utilizes a directed graph to capture the precedence of extraction of blocks and pit slopes in different bearings. Depth-first-search algorithm was used to traverse the graph for constructing the slope constraints in the MILP problem. TOMLAB/CPLEX was used as the implementation platform to efficiently integrate the mathematical solver package CPLEX with MATLAB. A case study on intermediate scheduling of an iron ore mine over twelve periods was carried out to validate the models.

Oct 1, 2009

By Garth D. Kirkham

The Problem The Don deposit is a series of two sub-vertical zones that pose a number of challenges with respect to modeling and interpolation. The first challenge is that, based on data and observations, the mineralization and, more importantly, the grade is layered or banded and is stratigraphically controlled. The second challenge is that, due to the undulations of the deposit and extreme changes in dip, using a standard oriented ellipse to guide the estimation process is not appropriate and does not result in an estimate that is representative on a local scale. In order to solve this problem an adapted methodology of relative elevation modelling, has been devised to effectively model and estimate deposits faced with these challenges. Relative Elevation Designed for bedded seam and gridded surface With variable dip and vertical grade variability

May 1, 2013

By R. W. Seedsman

In 1984 and 1985, two 7.6m diameter TBM tunnels were driven from the Donkin-Morien peninsula in Nova Scotia to access the Harbour coal seam. The design of the ground support was based on identifying zones of rock failure through the application of the Hoek Brown failure criterion and the early use of finite element analyses. In 1992, the mining project was abandoned and the tunnels allowed to flood. Monitoring data from the tunnel was subsequently used as a case study in the development of the concepts of brittle rock behaviour. In 2007, the tunnels were pumped out as part of a feasibility study into the reintroduction of longwall mining into the coalfield. There is a good match between observations of the collapse zones in the roof and sides of the tunnel and a simple elastic analysis using brittle parameters, a spalling limit of 5, and a low independent shear modulus. The brittle analyses form the basis of the design for the resupport of the tunnels.

May 1, 2009