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By E. M. De Souza, J. F. Archibald

This paper examines aspects of Canadian mine backfilling operations that may be implemented to assist in reducing solid waste production, lowering energy costs, and restricting Greenhouse Gas emissions. Many Canadian underground mines use backfill to mitigate environmental effects associated with tailings disposal. Backfill production and disposal are energy intensive processes that require an average energy cost of 37.7 MJ/tonne of backfill to complete. Mine backfills, in engineering applications, also commonly make use of cement as a stabilizing agent. Cement requires an additional energy cost ranging between 4,637 and 6,600 MJ/tonne to produce. The large energy needs associated with mine backfilling and cement production operations create significant CO2 and Greenhouse Gas emissions. Approximately 1 tonne of CO2 and Greenhouse Gas is emitted for each tonne of Normal Portland Cement produced. For single mines producing 3,000 tonnes of backfill per day, considering both backfill and cement emission source terms, total emissions of CO2 ranging between 120.36 tonnes and 169.44 tonnes/day are anticipated. In Ontario, mining operations contribute 700,000 - 840,000 tonnes/year of CO2 and Greenhouse Gas emissions to satisfy backfill cement consumption needs alone. Potential reductions of cement in backfill would significantly reduce emission of these gases and lower their adverse environmental impacts. This paper identifies alternate, equally effective and lower cost binder agent strategies for cement in backfill that may lead to cement consumption reductions. Post-consumer glass represents one such potential alternative backfill binder. Over 950,000 tonnes of glass are disposed of annually in Canada, two-thirds of which exists in the form of easily recoverable glass packaging that is not currently recycled or reused. The partial replacement of cement by waste glass may address goals for reducing non-recyclable glass waste disposal; enhancing mine back filling operations; reducing total backfill energy costs; and ultimately reducing Greenhouse Gas emissions levels currently generated by the Canadian mining industry.

Jan 1, 2004

By Shuji Owada

Scrap electrical and electronic appliances, so called "E-waste", are not a present target to be collected and recycled under Japanese regulations. This material, however, contains considerable amounts of base, precious, and rare metals and it is necessary to recover these elements for maintaining stable supply and establishing "the society of environmentally-sound material-cycle". This paper describes recent trends of rare metals recycling in Japan and technological approaches to achieve the above objective. Also a research work to concentrate rare metals from the printed wiring boards by combining brand new comminution and physical separation methods is discussed.

Jan 1, 2011

By Q. H. Bui

The elastoplastic self-consistent model is one of the effective models to study the initial microstructure effect on the mechanical behavior of bulk materials. However, the use of this micromechanics-based model which takes into account only the Hall-Petch relationship at grain level for predicting the grain sized effects on the strength of the deformed materials is not accurate yet because of the fact that the dislocation density contributes also to the strengthening of this kind of materials. In this study, a modification made to the Hill-Hutchinson elastoplastic self-consistent model was proposed for investigating the microstructure dependence of the mechanical behavior of cold-drawn 6063 aluminium tubes. Because of the novel modification, an estimation procedure with two steps was required to identify the parameters of this micromechanical model. An acceptable agreement between experimental and theoretical stress-strain curves was achieved.

Jan 1, 2011

By Takayuki Takasugi, Naoya Masahashi, Yasuyuki Kaneno, Satoshi Semboshi, Yusuke Kadoi

Cu–Ti alloy wires doped with and without a small amount of Ni were fabricated by over-aging and using intense drawing procedures. For both the Cu–Ti alloys with and without Ni doping, the over- aged microstructure was occupied fully with a coarse lamella of Cu solid solution and β-Cu4Ti plates precipitated discontinuously by grain boundary reactions. The full-lamellar microstructure was developed much more rapidly by aging in multi steps at 873 K to 723 K rather than by isothermal aging at 723 K. Ni doping in Cu-Ti alloy was also effective to accelerate the formation of the lamellar microstructure. When drawing the over-aged alloy with inferior hardness but superior electrical conductivity, the strength increased steadily and eventually exceeded that for the wires drawn from the peak-aged alloy. In addition, the electrical conductivity of the wires drawn from the over-aged alloy was always much greater than that from the peak-aged alloy. Eventually, the procedure of over-aging, followed by intense drawing, could enhance both the strength and electrical conductivity of Cu-Ti alloys, whichever they contain a small amount of Ni or not, rather than the conventional peak-aging and drawing process. INTRODUCTION Cu-based alloy wires, which have an excellent combination of strength and electrical conductivity, have attracted extensive attention for highly mechanically stressed electrical devices, such as conductive lead wires and wires in suspension springs. Cu-Be alloys are widely used for such electrical components owing to their combination of strength and electrical conductivity among industrial Cu-based alloys. However, since beryllium is potentially toxic and also a rare element, substitute materials for Cu-Be alloys have been searched for several decades. Age-hardenable Cu–Ti based alloys have been proposed as candidates because their mechanical and physical properties are comparable to those of Cu-Be alloys; however, their electrical conductivity is inferior (Datta & Soffa, 1976; Soffa & Laughlin, 2004). In order to satisfy the requirement of downsizing and streamlining electrical devices, further improvement of the mechanical and electrical properties of Cu–Ti alloy wires is needed. Age-hardenable Cu–Ti alloys, which contain approximately 3 to 6 at.% Ti, are typically prepared using a solid solution treatment above 1100 K and then aging at a moderate temperature of 700 K to 800 K. It has been revealed that the microstructural events during aging progress as follows (Soffa & Laughlin, 2004): (1) compositional modulation of the parent supersaturated Cu solid solution in an initial aging stage (Laughlin & Cahn, 1975), (2) continuous nucleation and growth of fine needle-shaped precipitates of metastable β’-Cu4Ti with a tetragonal structure in a peak-aged stage, and (3) discontinuous precipitation of cellular components laminating the plates of a terminal Cu solid solution and stable β-Cu4Ti with an orthorhombic structure at the grain boundaries in an over-aging stage. It has been also accepted that the highest number density of dispersed fine β’-Cu4Ti needles should contribute to maximal strengthening. On the other hand, decease of the strength in the over-aging stage occurs due to the replacement of the fine β’- Cu4Ti needles with cellular components containing coarse β-Cu4Ti plates, while the electrical conductivity is significantly enhanced due to the depletion of solute Ti in the Cu matrix. This suggests that a combination of strength and electrical conductivity for age-hardenable Cu-Ti alloys is in a trade-off relationship, and that innovative improvement of both properties might be limited to tuning the aging conditions.

Jan 1, 2019

By D. Michaud, C. Bazin, S. Lévesque, L. Pérez-Barnuevo, H. Longuepée

In recent years, with the emergence of Geometallurgy, a great effort has been made to characterize ore resources as early and accurately as possible, to allow better design and a more efficient operation of mineral processing circuits. In this context, core logging plays an important role, since drill cores provide the first insight into the ore characteristics. However, to satisfy geometallurgical requirements, traditional core logging does not suffice. New tools and methodologies need to be developed for the automation of core logging and the acquisition of mineralogical data better related to mineral processing performances. In this paper, a methodology for the geometallurgical characterization of drill cores is proposed, based on the drill core textural patterns. Textural pattern is defined here as the macroscopic spatial arrangement of minerals. The Mont-Wright iron ore deposit (Quebec, Canada) is used as a case study. The first part of this work aimed at analyzing the potential link between the iron ores textural patterns observed in drill cores and their response to ore processing, namely comminution and concentration. Preliminary results show similar performances in terms of energy consumption and heavy liquid separation for samples showing the same textural pattern. In the second part, this work seeks to develop a methodology for the automated identification of drill core textural patterns by the application of digital image analysis and discriminant function analysis. The results obtained show that this methodology is able to discriminate between the textural patterns identified at Mont-Wright with a good rate of success. Therefore, this work lays the foundation for the development of a new drill core characterization tool, which would allow for the early prediction of the iron ore behaviour during mineral processing through the identification of drill core textural patterns.

Jan 1, 2016

By J. Pepin

When using alternating current submerged arc welding (SAW) to produce pipes from microalloyed linepipe steels, it is critical to balance penetration depth and deposition rates, in order to minimize the number of weld passes while still maintaining good heat affected zone (HAZ) microstructures and properties. A series of bead-on-plate (BOP) submerged arc welds were performed on X70 steel, using different waveform variable settings (i.e., balance, offset and frequency). Weld bead cross-section profile deposition and penetration areas were measured, and both Vickers hardness and Charpy V-notch impact testing were performed. Both single electrode and tandem electrode welds were evaluated.

Jan 1, 2011

By R. H. McMillan

A classification of important uranium deposits which utilizes both genetic and descriptive criteria is presented. The dual aspect is useful because, while the non-genetic nomenclature for the different deposit types is amenable to various interpretations, the critical characteristics of each deposit type can be analyzed to clarify various genetic points. Although the classification is intended primarily for Canadian uranium deposits, most of the important deposit types known elsewhere can be accommodated.

Jan 1, 1978

By M. Yavuz

As a branch of Operations Research, decision making is a widely used application in both science and social sciences. There are many different methods developed to solve decision making problems in the literature. In this study, Fuzzy Analytic Hierarchy Process (AHP) method is performed for the selection of reclamation project selection in an open pit mine and the optimal solution of the problem is investigated. Different reclamation project alternatives are prepared for an open pit mine, which continues to its production activities in magnesite sector in Turkey. The data obtained from Magnesite Cooperation is used in the application of the method. A decision-making process is prepared as considering the project alternatives for the purpose of selecting the most suitable reclamation project. The entire criteria that affect the decision-making process are identified and transformed into a hierarchical structure. The problem is solved by using Fuzzy AHP method developed according to this structure. It is found that Fuzzy AHP is a method that may help decision-makers in solving different decision-making problems in mining.

Aug 1, 2013

By D. P. Bishop, G. J. Kipouros, R. L. Hexemer Jr., I. W. Donaldson, W. F. Caley

Aluminum powder metallurgy (APM) is an advanced metal forming technology frequently employed to fabricate complex structural components in a near-net-shape fashion. Exhibiting nearly 100% material utilization, APM continues to rise in popularity. Recent research initiatives in this field have emphasized the development and processing of advanced 2xxx and 7xxx series alloys. In particular, APM equivalents to wrought 7075 and 2024 have been sought. An overview of work completed in this area is presented. Included are data on the various production stages (powder compaction, sintering, forging, and heat treatment) as well as the microstructure and mechanical properties of the finished products.

Jan 1, 2010

By Walter I. Nelson

THE geology of the Copper Mountain mine has been ably described by Dr. Victor Dolmage in Memoir 171 of the Geological Survey. Reference is invited to that paper for a more extended description of the geology of the ore deposits than will be given here. The important orebodies of the mine occur in fragmencal volcanic rocks, parallel with and adjacent to the gabbro of the Copper Mountain stock. In the mine area, the contact strikes N.45°W. and dips either vertical or steeply co the southwest. For a distance of 500 feet or more from the contact, the fragmental rocks have been intensely metamorphosed both dynamically and hydrothermally. The dynamic effects are reflected in the foliation and fracturing parallel with the contact, which occurs throughout the mine, and the volcanic rocks within this foliated zone are, in places, highly schistose. Superimposed upon thi.s structure is a system of fine, straight, parallel frac-tures that strike nearly normal to the foliation (and contact) and dip between 65° and 75° to the north; it is with this last-described fracture system that the ore minerals are structurally associated. The fractures are mineralized with bornite and, to a considerably less extent, with chalcopyrite and some pyrite. A notable characteristic is the extreme fineness of the fractures; even in high-grade ore they are rarely larger than pencil lines. The tenor of the ore, therefore, varies directly with the fracture spacing. Replacemcnr of the host-rock between two or more fractures, varying in degree from finely disseminated sulphides to masses of nearly solid bornite up to 18 inches wide and 2 to 3 feet long, is not uncommon in the higher-grade portions of the orebodies. Two structural types of orebody are recognized in local nomenclature: the 'contact' orebodies, so-called because they occur along the contact; and 'outlying' orebodics, which are enclosed in the volcanics. The former arc tabular or lenticular bodies elongated along the strike and dip of the contact. The 'outlying' orebodies are coniform, chimney-like masses roughly elliptical in plan; with depth, their roots plunge at steep angles toward the contact. All of the orebodies are cut by a number of light-coloured granophyre and felsite porphyry dykes. These dykes-the so-called 'mine' dykes -enter the mine area from the north, curve gently southeasterly across the orebodies, and then cross the contact into the gabbro at the south end of the mine. All the dykes dip vertical to steeply east.

Jan 1, 1941

By L. Li

Backfill is increasingly used in underground mines, as it can help reduce the environmental impact from mining operations. However, the primary objective of backfilling is to provide safe working space for miners, by improving ground stability conditions. As cement is often added to the backfill, a critical issue is the determination of the required backfill strength (cohesion) due to the binder. This value is usually obtained from a solution proposed by Mitchell and co-workers, in the early 1980?s, for stopes with an exposed backfill face. This paper presents a brief review of the Mitchell et al. solution, with some of its main limitations. Some of the recently developed solutions for backfill design are then summarized and discussed.

Aug 1, 2013

By Charles Amoah

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By Fabio Terzi

In this investigation some preliminary results are reported about the electrochemical oxidation of CO using goldbased encapsulated nanoparticles grafted on conducting substrate. The investigation has been planned in four steps: 1. production of Au(111) substrate and modification with self assembled monolayers; 2. synthesis and embedding of nanoparticles; 3. grafting of encapsulated nanoparticles on electrode substrates; 4. investigation of CO electroxidation on the modified electrode. The systems were characterized by means of various techniques (spectroscopic, microscopic, and electrochemical methods), obtaining information about SAM's structure and morphology, size and composition of nanoparticles and electrochemical behavior of modified electrodes.

Oct 1, 2003

By N. J. Contini, R. W. Knopp

"In March 1988, old Denver flotation cells were removed from Dickenson's Arthur w. White Mill, and a new flotation circuit, consisting of four Prochem rougher cells and a Hydrochem agitated cleaner column, was commissioned. The refractory portion of the gold in the ore is associated with arsenopyrite, therefore the flotation circuit is set up to produce a saleable sulphide concentrate. Tailings from the leach circuit are conditioned prior to being pumped as feed to the flotation circuit. The prototype Hydrochem agitated column has been in operation as a single cleaner stage for rougher concentrate. The effect of flotation circuit changes on gold recovery data, as well as cleaner concentrate production, and development work to achieve the target results, have been investigated. Flowsheet modifications and the resulting circuit performance data, along with test results to date, will be presented.INTRODUCTIONThe mill is capable of treating 1000 stpd of ore averaging approximately 0.30 oz/ton Au. The ore is crushed and ground to 75% - 200 mesh. Gravity concentration, cyanidation, and Merrill - Crowe precipitation yields 84% gold recovery. Detailed descriptions of the comminution, gravity separation, and leaching circuits, as well as background information have been presented elsewhere (Suttill, Van Weert et al). The target cleaner concentrate grade is 1.0 oz/ton Au for custom smelting and refining. Historical gold recovery values of the old circuit was approximately 20% of the gold present in the float feed at the target grade. The recovery value objective set for the new circuit during the planning stages was 50% of the gold present in the flotation feed at 1.0 oz/ton Au in cleaner concentrate."

Jan 1, 1989

By Glen Robertson, Jeff McLaughlin

"The Clarabelle Mill rock tailings have the potential to generate sulphuric acid through chemical and biological oxidation of sulphide minerals. Current rock tailings assay between 0.80 -1.40 %S, with sulphur occurring principally as coarse pyrrhotite. Acid generation within the tailings area can be substantially reduced by segregating pyrrhotite rich tailings in a submerged storage area and by depositing only low sulphur rock tailings in exposed areas. Laboratory tests confirmed that low sulphur tailings could be produced by flotation at reduced pH with a small xanthate addition. A plant test was conducted to evaluate the production of low sulphur tailings in conjunction with INCO's continuing commitment to environmental protection and progressive decommissioning of the metallurgical site.During the plant evaluation, approximately 5% of the mill rock tailings were reprocessed in a line of 100 tt3 Denver flotation cells. Tailing grades below 0.40% S were easily achieved through operation at pH 6 -7, with xanthate addition (dosages up to 0.02 lb/ton) and 10 -15 minutes of nominal retention time. Froth depths between 1 -3 inches combined with relatively liberal amounts of frother were required to pull the lightly mineralized froth into the concentrate which averaged 11% sulphur and less than 5% mass recovery. In addition, three field lysimeters were each filled with two hundred.ton bulk samples of low sulphur tails (0.35% S), standard rock tailings (0.98% S), and mill total tailings (2.30% S) for long term monitoring. The implications for full scale plant design, tailings area decommissioning, the possibility of increased nickel recovery and preliminary field lysimeter data are discussed."

Jan 1, 1994

By Georges Croisé, Les-Lee Thompson, Adrien Debergé

Membrane filtration systems have regained focus in recent years as an effective means of liquid-liquid separation to increase the concentration of valuable elements, recover reagents or remove impurities. ORANO Mining (formerly AREVA) investigated this cost optimization process opportunity as early as 2011 for implementation at the Trekkopje project (Namibia). The key focus was to separate and recycle bicarbonate from the uranium bearing eluate solution. The performance targets were successfully achieved at lab- and pilot scale with an ultrafiltration and nano-filtration configuration system. Early 2015, ORANO Mining further launched an investigation into the use of membranes for acid recycling at the KATCO In Situ recovery mine in Kazakhstan based on the favorable results from the original bicarbonate application. KATCO is the world leader in ISR uranium mining with an eluate processing capacity of 80 000 m3/yr. This site consists of two processing plants namely, Muyumkum and Tortkuduk, located 40 kilometers apart, both operating under acidic conditions whereas precipitation and packaging are based in Tortkuduk only. This paper serves to present the results from the integration of a nano-filtration system at the Muyumkum satellite processing plant. The project consisted of screening laboratory bench studies conducted at ORANO-CIME followed by process validation at KATCO through further bench and pilot test work. The feasibility study assessments were successfully concluded which led to the implementation at an industrial scale in Muyumkum of a nano-filtration process to reduce eluate volumes being sent to the uranium precipitation section whilst achieving effective separation of uranium from sulfuric acid. Nano-filtration technology has drawn significant attention due to the efficiency and reproducibility of the process and its moderate capital cost relative to operational savings. The reliability of the previous results is a great opportunity to reduce operative expenditures within ORANO’s next ISR mining project in Mongolia.

Jan 1, 2020

By J. Schick, V. Granger

Nowadays, all French former uranium mining sites are remediated and redeveloped. If needed, mining waters containing radium have to be treated before discharged into the environment. Classical radium treatment consists in a (Ba,Ra)SO4 salt precipitation and radium monitoring was carried out using a time-consuming analysis called emanometry. Three zeolite samples have been tested to remove 226Ra from mining water. In batch experiment, radium was totally (R=100%) and quickly removed after 2 minutes contact time. Continuous sorption experiments were carried out through a vertical column at lab scale. Chabazite is the most efficient zeolite with an 226Ra activity below 0.2 Bq/L until 60000 Bed Volume. Chabazite is always efficient although radium content in material reaches 150 Bq/g. 226Ra uptake was also tested at semi-industrial scale on a pilot plant. More than 3000 m3 were successfully treated with a radium content below 0.1 Bq/L. The environmental impact assessment of Ra-chabazite was characterized by using batch leaching tests made according to the NF EN 12457-2 standard as applied on all wastes. Ra-chabazite stability is excellent during this test: radium leaching is very low, less than 0.005%. A new 226Ra measurement method was developed by ICP-MS for a better analysis reactivity. This new method was carried out in a couple of minutes with a lower sample volume than emanometry. The validation was performed according to the French NF T90-210 standard for the calibration function definition, the limit of quantification, the accuracy and the interferences.

Jan 1, 2020

By H. J. lgner

Hydraulic fills are widely used in the tabular, steeply dipping stopes of the South African gold and platinum mines as an integrated process within a daily cycle of drill and blast. There is therefore only a small time window in which to fill the geotextile bags used as primary fill containment, without the risk of loosing production. Consequently, mines tend to increase the flow rate to the stopes, although this compromises adequate drainage, consolidation and strength development during filling. Recent underground measurements inside the geotextile bag have revealed that at high rates of rise and at 25 degrees dip, the backfill can remobilise within a limited area inside the geotextile bag during filling. This sudden downward surge of backfill exerts, for only a few seconds, additional loading on the geotextile, its supporting mesh and the props. This unstable behaviour poses a serious threat as it can push props out of place, thereby damaging the geotextile bag and causing a mud slide in the stope. To reduce the risk of accidents, the phenomenon of sudden slumping was further investigated for various filling conditions in the laboratory. The results confirmed that the maximum pressures associated with the sudden slumping can be more than five times those experienced during steady-state consolidation. Based on this new insight, the current best practice for hydraulic backfilling was critically reviewed. A practical approach to implementing meaningful standards is presented to ensure safe operations in relation to the consistency of the backfill quality and the appropriate matching of geotextile characteristics with backfill properties.

May 1, 2007

By H. Wotruba, L. von Ketelhodt, M. Kowalcyk, C. Kleine, M. Robben

Sensor-based sorting is a financially and technically viable technique that is operating with little or no water and relatively little power consumption. Sensor-based sorting has already proven its operational stability at two gold applications in South Africa. Sensor-based sorting cannot only turn waste dumps and diluted mining blocks into reserves. The implementation can also cause a decrease in specific operating costs of mill and mine when for example replacing selective mining by bulk mining methods with subsequent sorting. Successful installations, operational experience, test work data and flow sheet integration from mine-to-mill underline the impact and potential that sensor-based sorting can have on the gold mining and processing industry.

Jan 1, 2011

By M. Abdellatif

Successful demonstration of The Mintek Thermal Magnesium Process (MTMP) was achieved in November 2004 at the pilot-scale, About 30 tons of magnesium producing recipe was smelted in the DC arc furnace over a continuous operation of 8-days, Twenty-two furnace batching-tapping operations were carried out at a feed rate of 525kg/h and a smelting temperature of 1600-1700°C, The MgO content in the produced slag was as low as 6,7%, and averaged 9,2% MgO, resulting in an overall magnesium extraction of 77%, which reached 87% during good operating periods, Magnesium vapour was extracted at a rate of 70-85kg/h and was delivered to the condenser that was operated at 680-720°C, The magnesium was captured in the condenser crucible in a liquid state, allowing its prompt tapping, More than 3500kg of crude metal were produced over 15 on-line metal tapping operations, On average, a condensation efficiency of 85% was achieved during the entire testwork, which peaked at 87% during steady operations, The quality of the crude metal was similar to, if not better than, that of the Magnetherm's crude magnesium, A pre-feasibility study has indicated that the MTMP has the potential for lower capital and operating costs as compared to the electrolytic process, and therefore Mintek and its consortium partners are exploring opportunities for a commercial production facility.

Jan 1, 2006