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By J. K. Szymanski

"RÉSUMÉPour maintenir de bonnes performances technique et économique dans l’exploitation par chambres vides (open stope) il est primordial d’assurer un contrôle efficace des limites réelles des chantiers d’abattage. C’est pour cette raison que, de plus en plus souvent, les opérateurs miniers utilisent un dispositif de laser (Cavity Monitoring System: CMS) qui permet de mesurer les dimensions réelles de chantiers en vue de calculer principalement la dilution et les pertes du minerai ainsi que d’autres paramètres. Malheureusement, il n’existe présentement aucune méthodologie commune, qui permettrait d’interpréter ces résultats selon les mêmes critères pour faciliter d’évaluations juste et précise de la réalisation par rapport à la planification en vue d’en apporter de corrections, dans les différentes opérations minières, si nécessaire. Dans la première partie du présent article on discute les principales séquences d’exploitation utilisées dans l’extraction par chambres vides. Par la suite, à l’aide des sections transversales et longitudinales on illustre toutes les phases des travaux miniers. Ceci en vue de permettre au lecteur de comprendre mieux c’est qui peut se passer effectivement dans les chantiers d’abattage. Par après on donne les définitions générales de principaux facteurs de performance technique. Finalement, l’exemple numérique, élaboré à partir des résultats de l’arpentage au laser effectué par la mine Bousquet 2 dans un chantier d’abattage, donne les détails concernant les définitions ainsi que les valeurs de nombreux facteurs de performance technique, qui pourraient être utilisés, par après, par les opérateurs miniers dans le suivi de leurs exploitations souterraines."

Jan 1, 1997

By Alan Galley, Tom Hynes, Michel Plouffe

"Mining in Canada’s economy• Employs 320,000+ workers; Wages 30-60% above other sectors• Operates 220 producing mines, 33 smelters and refineries• Paid $8.4B in taxes and royalties to governments in 2010• Invests about $30B in capital projects annually • Largest private employer of Aboriginal Canadians 2• Core supplier to clean-technology sectors• Attracted 18% of world exploration spending in 2010• Efficient TSX processes - 1400 mining companies listed, ~50% of mineral projects are outside Canada• Estimated 1000 Canadian companies in 100 countries• Minerals account for 21% by value of Canada’s goods exports• Top 5 World Producer in uranium, potash, nickel, platinum, aluminum, diamonds, zinc, met coal"

Jan 1, 2012

By J. E. Moran

A groupd of French capitalists, La Compagnie Française des Mines d'Or du Canada, has undertaken the considerable task of developing Otter creek, in the Atlin district, B.C., by hydraulic mining methods. It has long been known that the gravels of this stream carry sufficiently high values in gold to make it attractive as a mining venture, but it was impossible to ignore the existence of formidable natural obstacles to hydraulicing them, and these needed to be taken into serious account before embarking upon any costly programme of development. The tide to the Otter Creek leases was originally held by Mr. H. Maluin, a French engineer well known throughout the north, to whom was to fall the task of financing whatever programme might be decided upon. It was he, too, who would have to assume the responsibility of finally passing judgment upon the practicability of the various devises for overcoming the adverse natural conditions. With an infinite attention to detail, which I believe to be a characteristic of the French people generally, he studied his problem and was finally able to submit to his financial backers a programme which left the very minimum possible to the hazard of accident or chance. Dr. Mandy, on his visit to Otter creek this season, expressed the opinion that our method of opening this difficult creek presented certain features which might be successfully applied in placer operations elsewhere in British Columbia, and it is largely for this reason that the present paper has been prepared. I shall set forth, as well as I can, the practices which have enabled us to overcome rather easily some of the obstacles which nature had unkindly placed in the path which we must take. The natural flow of water in Otter creek is far too little to deal success-fully with the rather excessive amount of glacial drift overburden which lies directly over the gold-bearing gravels. For this natural defect, the only remedy was to procure more water. This we have clone through a system of flumes and ditches, totalling between ten and eleven miles in length, which bring to the mine a supply of water adequate for our needs.

Jan 1, 1932

By B. A. Zaharov, J. M. Shneerson, L. V. Chugaev, M. T. Zhunusov, A. M. Markelov, S. V. Drozdov

The main direction of research was the application of autoclave technology for the flotation concentrates or biooxidation feedstocks. The industry modernization also expects the possibility of increasing the yield of the flotation concentrate, to allow an increase in gold extraction in flotation circuit. This paper provides brief description of results obtained for concentrates with the yield of 4 and 8%, as well as corresponding biooxidation feedstocks. Technological efficiency of autoclave oxidation is shown for both concentrates and biooxidation feedstocks. The process has been evaluated on a laboratory and a continuous pilot plant scale. Gold extractions from POX discharge are ranging from 94-97% for each product, with only 5-7 kg/t cyanide consumed.

Jan 1, 2014

By J M. Gibbs

Craigmont Mines Limited mine 50,000 tons of ore and waste per day from the open pit at Merritt, British Columbia. An electric-powered "down-the-hole" drill, a diesel-powered rotary drill and two electric-powered rotary drills have been used. All primary drilling, as a result of cost and operating experience, is now performed with two electric-powered rotary drills. Trials with various loading techniques have increased the amount of AN-FO and decreased the amount of commercially prepared slurries used for primary blasting. Approximately 95 per cent of the primary blasting is accomplished with AN -FO, mixed at the hole. Introduction THE Craigmont mine is located near the village of Merritt, B.C., 240 miles northeast of Vancouver. The concentrator has been in production since September of 1961. Craigmont is a combined open-pit and underground operation. To date, slightly more than 95 per cent of the mill feed has been mined from the open pit. As underground development proceeds, the ore requirements from the open pit will decrease. The average milling rate from September, 1961, to April, 1964, was approximately 4,900 tons per day.

Jan 1, 1965

By Jing Li, Weiqiang Lai, Joe Zhou, Jiezhen Ma, Shuibo Chen, Ashele Copper Company, Feng Gao, Guofu Feng

"Copper-zinc ores often contain gold and silver, which can be recovered into copper concentrate by flotation as by-product. The challenges for operations that produce copper, zinc, gold and silver are the separation of copper and zinc and the low grade of precious metals. Ashele copper-zinc ore in north China contains 2.38% Cu, 0.69% Zn, 0.21 g/t Au and 18.10 g/t Ag and the plant produces copper and zinc concentrates, with gold and silver being recovered into copper concentrate. Copper occurs mainly as chalcopyrite and Zn occurs as sphalerite. Copper is well recovered with a recovery of over 94%. However, the recovery of Zn is substantially low (around 50%) due to fine grain size of sphalerite. In addition, gold recovery is much lower than expected and only 33% of gold in the flotation feed was recovered. The grade of gold in copper concentrate is also lower than the required payable grade (1.0 g/t). To determine the cause for lower Zn and Au recoveries, a plant survey program was conducted on the operation. The information acquired shows that the loss of Zn was mainly in the copper concentrates (accounting for approximately 38% of the head assay); of which, 24% was liberated, 8.5% was associated with chalcopyrite and 4.6% was associated with pyrite, indicating that the separation of copper and zinc was the main cause for the Zn loss, with liberation being the second cause for Zn loss. Future effort in improving Zn recovery should be focused on the separation of zinc from copper. Gold in the ore occurs as both microscopic gold and submicroscopic gold, accounting for 36% and 64% of the head assay, respectively. Microscopic gold occurs mainly as native gold and electrum; it is relatively coarse with a grain size of 10 to 240 µm and a large portion can be recovered by gravity. Submicroscopic gold was mainly carried by pyrite (accounting for 38%), and to a less extent, by tennantite (15%) and chalcopyrite (10%). Gold in sphalerite is nominal (1%). It is suggested that more coarse gold and tennantite be recovered and a gold recovery increase can then be achieved to obtain a copper concentrate with over 1.0 g/t Au through flowsheet optimization. Gravity concentration should be investigated and may be worth added into the existing flowsheet to maximum the gold recovery and grade.INTRODUCTIONCopper-zinc ores containing gold and silver is a subtype of polymetallic sulphide ores. Unlike porphyry copper sulphide ores and iron-oxide copper-gold ores, this type of ores often contains substantial amounts of zinc and lead. Polymetallic sulphide ores are mainly distributed in Canada, such as at the LaRonde and Horne deposits. Other examples include Mt. Morgan in Australia and Boliden in Sweden. Globally, production and reserves from gold-rich VMS deposits account for 1370 t gold. This is equivalent to 1% of the world production and reserves, whereas the Canadian total for gold-rich VMS deposits is 870 t, representing close to 10 % of Canadian production and reserves (Gosselin & Dube, 2005a, 2005b). Flotation is the principal process for processing the copper-zinc sulphides ores, for subsequent smelting, roasting, or hydrometallurgical treatment. Oxidized copper-zinc ores can also be processed using leaching technology. For example, at LaRonde operation (a Cu-Zn-Pb ore containing 3-4 g/t Au and 60-100 g/t Ag) the flowsheet consists mainly of a copper flotation circuit and a zinc flotation circuit followed by a cyanidation process of flotation tails. The precious metals are recovered with copper concentrate, zinc concentrate and cyanidation of zinc tails via Merrill Crowe precipitation (Zhou et al., 2005)."

Jan 1, 2016

By R. L. Bruening, N. E. Izatt, S. R. Izatt

"Rare earth elements (REE) are essential and unique components of many high-technology products without which functioning of modern society would be greatly impaired. Commercial deposits of REE are limited to a few geographical locations. Largely untapped sources of REE are available in endof- life (EOL) magnets, rechargeable batteries, and electronics. Presently, < 1% of REE in EOL wastes is recycled. Conversion of EOL wastes to liquid streams allows use of IBC’s Molecular Recognition Technology (MRT) process to selectively recover, separate, and purify target REE and associated metals at g/L to mg/L or lower concentration levels. The MRT process together with its applications to separations of REE and associated metals in recycling as well as in mining are described. Economic and environmental advantages of MRT are presented. INTRODUCTIONRare earth elements (REE) include the lanthanide series (La-Lu), Y, and Sc. These elements are not rare, but concentrated minable deposits are scarce (Cordier 2012; Haxel, Hedrick, & Orris, 2002). Over 95 % of the world’s supply of REE is controlled by China (Hanson, 2011a) where they are mined, processed, and the pure elements incorporated into a growing number of consumer and military products. The consumer products are marketed worldwide. Since REE are vitally important in consumer and military products, this situation has caused other nations to scramble to develop the capability to produce their own supply (Cordier, 2012).In the U. S., Molycorp has reopened the Mountain Pass REE mine in California and production has begun (Goldenberg, 2010). Development of a reliable internal source of REE is of high national priority in the U.S. (Hanson, 2011b; Hess, 2012: “Obama Announces”, 2012). These elements have in recent decades been incorporated into new consumer and military products that are essential to our economy and defense. These products range from wind turbines, high performance magnets, hybrid car rechargeable batteries, energy efficient lighting electronics, flat screen televisions, and smart phones to advanced weapons systems (Haxel et al., 2002; Levkowitz & Beauchamp-Mustafaga, 2010)."

Jan 1, 2012

By O. Babak, J. G. Manchuk

ABSTRACT A significant factor in evaluating bitumen recovery from an oil sands mine is the particle size distribution (PSD). Increased understanding of mined ore quality and improvement in predictions of recovery can be achieved through PSD modeling. This paper addresses PSD modeling using geostatistics. PSDs may be described using many discrete particle sizes, making this a challenge. The approach parameterizes PSDs with a few statistics. A lookup table is used to reconstruct the PSDs based on models of the statistics. The workflow is applied to Total E&P Canada’s Joslyn Lease and yields good results that reproduce input statistics without introducing artifacts.

Jan 1, 2013

By A. M. A. Mohamed, F. H. Samuel, S. Valtierra, H. W. Doty, A. M. Samuel

"The influence of Fe, Mn, Cu and Mg alloying additions, Sr modification and grain refinement on the microstructure of as-cast and solution heat-treated Al-10.8% Si alloys was investigated using optical microscopy and EPMA techniques. The results showed that the modification effect of Sr diminished with increasing Cu and Mg additions, due to Sr-Cu-Mg interactions. Strontium caused segregation of AlzCu in areas away from eutectic Si regions, and altered the precipitation sequence of the a-Ah5(Fe,Mn)3Siz iron intermetallic from post-dendritic to pre-dendritic, with the phase observed within the a-Al dendrites. Depending upon the alloy Fe and Mn content, a coarser variation (""sludge"") of the a-Fe phase occurred, in the form of polyhedral shaped particles. The AhCu phase dissolved almost completely during solution heat treatment, while Al5Cu2Mg8Si6, sludge, and a-Aln(Fe,Mn)3Siz phases persisted in all alloys, particularly at high Mg and Fe levels. The f3-Al5(Fe,Mn)Si phase dissolved partially in Sr-modified alloys, the dissolution becoming more pronounced after solution heat treatment."

Jan 1, 2006

By P. G. Smith, A. Axiuk

The objective of this paper is to present, from a practical perspective, a review of the most relevant maintenance procedures that are accepted or prescribed to be the most effective in optimising service life potential and to ensure continued safe use of steel wire ropes for shaft mining applications. The paper will address the most common operational issues encountered in the care and operation of shaft ropes for both conventional drum hoists and multi-rope friction winders. For each distinct maintenance procedure presented, a limited amount of theory is discussed to identify the underlying mechanisms at play that must be addressed and to emphasize the logical basis for the recommended course of action. It is recognised that each installation is unique and that the recommended maintenance procedures may not always be practical or cost effective from an operations standpoint under select circumstances, however the intent remains to promote industry best practices for the knowledge and benefit of the mine hoisting community, from experienced maintenance personnel to new entrants to the industry alike.

Jan 1, 2023

By M. Dupuis, V. Bojarevics

It is well known that horizontal current density in the metal pad contributes greatly to the generation of MHD driven bath-metal interface wave. It is possible to compute very accurately the metal pad current density using a very detailed finite element model [1], but a MHD model must be compatible to this level of mesh refinement and to recalculate the current distribution at each time step, including the full busbar supply system. The accuracy of the instability prediction of the cell depends on the accuracy of the metal pad current density calculation. This study presents the comparison of the metal pad current density calculation of the detailed finite element model and the MHD-Valdis model for different metal pad heights and ledge thickness. It also presents the corresponding cell MHD stability predictions.

Jan 1, 2006

By R. Howard

"In projects involving resource development and plant optimization, the use of in-mine geophysics can deliver considerable benefit. The value proposition lies in using very high resolution downhole measurements to model process-plant outcomes. The calibration procedure used to convert in-situ physical properties into process engineering parameters is illustrated using two iron ore projects. Data correction was related either to orebody structure or mineral formation. The deliverable from this approach is a series of high-definition sections indicating the variability of ore delivered to a front-end separation plant and parameters for mine scheduling and stockpile design needed for maximum product yield.RÉSUMÉ Dans des projets de développement des ressources et d’optimisation de l’usine, l’utilisation de la géophysique minière peut engendrer des bénéfices considérables. La valeur de la proposition réside dans l’utilisation de diagraphies à très haute résolution afin de modéliser les résultats de l’usine de traitement. La procédure d’étalonnage utilisée pour convertir les propriétés physiques in situ en des paramètres d’ingénierie de procédés est illustrée en se basant sur deux projets de minerai de fer. La correction des données porte sur la structure de la masse minérale ou de la formation minérale. Les livrable attendus de cette approche sont une série de sections à haute définition, signalant la variabilité du minerai livré à une usine de séparation de première ligne, des paramètres pour l’échéancier de la mine et la conception des haldes requis pour une production optimale."

Jan 1, 2016

By M. Pfeifer, M. N. Brodie, D. J. Barratt

"This paper reviews design trends related to the various SAG mill configuration and drive options available today. The impact of these options on capital and operating costs is assessed, and key technical issues reviewed. The discussion is based on the conventional North American ’pancake’ mill configuration. IntroductionDuring the past decade mill technology has evolved significantly in the following key areas:• improvements in variable speed motors continue with on-going advances in electronics;• ring motors, or gearless drives, are becoming more common in mill sizes 32 ft and larger, with ratings of 10 000 HP and greater;• geared drives have become available up to ratings of 9500 HP per pinion, compared to the earlier 6000 HP guideline;• improvements in speed reducer technology due to the use of carburized and ground precision gearing, make the high speed motor-speed reducer drive more competitive with the direct coupled low speed motor drive;• a unique speed reducer drive is being introduced to this industry which combines ring gear drive pinions with speed reduction. mprovement in gear alignment is claimed, and the overall drive arrangement is more compact than is possible with a conventional speed reducer drive;• the first 38 ft and 40 ft diameter mills have been designed and manufactured; and • application of large multi-shoe bearings have made shell supported mill configurations available for all, including the largest sizes. These designs have flat instead of conical mill shell ends, and have the potential for technical and cost advantages compared to conventional trunnion supported designs.This proliferation of mill design features provides several options to those involved in planning and design of milling plants, and requires more extensive evaluation to optimize mill design features to best suit specific project requirements."

Jan 1, 1999

By J. Ga?parík

The optimal selection of machine or machine group for building processes is very important role of building planner during the process of building planning. During this process building planner have to analyze several factors influencing the final effective decision concerning this problem. There are several factors and criteria for effective selection of building machines. In our contribution there are analyzed: ability of machines to realize designed building process (quality aspect), duration of mechanized process (time aspect) and minimizing of energy consumption (cost and environmental aspect). Selected scientific methods and theories of problem solution can be divided into these groups: theory of system (creation of building machine selection method), multi-criteria optimizing method (analysis of mechanized building process from the point of more optimal criteria), queuing theory (application during the mathematical modeling of mechanized soil processes), method of scientific analysis (analysis of factors influencing final decisions), method of scientific synthesis (creation of optimizing method implemented into building processes and possible application in construction sector). Multi-criteria optimizing method were during our research work implemented into soil processes and selected building group machines (excavators and trucks), which are very often used in construction and mining processes. This method can be considered as a multi-level decision making process based on multiple parameters. In our contribution is presented key mathematical models for model example solution and software built in Java, which has been created as a support for method described in this contribution. Application of this method and software will increase the effectiveness of building machine selection from the point of key criteria of optimizing: quality, time and energy consumption.

Aug 1, 2013

By F. Ajersch, A. R. Hekmat

Apparent viscosities of hypo-eutectic (Al-7% Al) and hyper-eutectic (Al-35% Si) binary alloys were measured in the semi-solid state using a Couette type viscometer at variable shear rates. Analysis of the microstructural evolution demonstrates the differences in the rate and degree of attrition of the primary phase particles which are characteristic of the thixotropic nature of the semi-solid alloy. It was observed that the Si primary phase in the hyper-eutectic alloy is much more difficult to fragment than the dendritic a-Al phase in the hypo-eutectic alloy. For the case of the a-Al, the dendritic structure is broken down by attrition and fracture of the dendrite arms whereas the fracture of the Si hexagonal crystals in the hypereutectic alloy occurs along the {100} and {110} cleavage planes. Results are presented for fixed solid fractions of the primary phase at isotherm condition for each type of alloy.

Jan 1, 2006

Presentation Overview Corporate Overview Kutcho Project History Exploration Development Permitting Capstone -Pursuit of Value Building a mid-tier copper producer focused in the Americas Two operating copper mines; Cozamin& Mintomines High grade and low cost 2010 forecast: 80-85 million pounds of copper in concentrates Total Cash Costs* of ~US$1.10/lb to US$1.20/lb of payable copper produced Significant by-products of gold, silver, lead & zinc Growth potential Further expansions at existing Cozamin& Mintomines High grade copper development: Kutcho project, BC Investments in Nevada Copper & Silver Wheaton 100% North American assets Low risk ?Canada & Mexico ?Conventional operations

Oct 1, 2010

By G. Tairova, M. Murchie, B. Esford, E. Lam

"The objective of this project is to investigate methods to lower the sulphate concentrations in the mill effluent. Currently, the concentration of sulphate in mill effluent is approximately 2 g/L. The high concentration of sulphate ion in the effluent has the potential to become a regulatory issue. The target sulphate concentration in mill effluent for this work was less than 500 mg/L. The pilot studies, using sulphate precipitation, were carried out at the mill. The results of the sulphate precipitation pilot study, using calcium hydroxide and sodium aluminate, indicated that:• The sulphate concentrations in effluent could be reduced to less than 500 mg/L.• The concentrations of most other elements of concern, such as selenium, arsenic, cobalt, nickel and vanadium, were also reduced.INTRODUCTIONHistorically, the concentration of sulphate, SO4 2-, in water has not generally been subject to regulation. However, with the increasing global consumption of water, stricter regulations on sulphate quantity may be imposed. Sulphate is a concern in process waters as it forms scale on process equipment and leads to operational problems. High sulphate concentrations may result in adverse health effects. The taste theshhold for the most sulphate salts in drinking water ranges from 250 to 500 mg/L.A literature search and review to identify methods to reduce sulphate concentration in the mill effluent was carried out. A number of methods were selected and tested in the lab. The experimental results indicated that the precipitation methods, using calcium hydroxide and aluminum compounds, barium compounds, as well as the ion exchange and the membrane methods, were effective for the removal of sulphate to below the required limits. Some other elements, such as vanadium, nickel, cobalt, selenium and molybdenum, were also removed.The process, using calcium hydroxide and aluminum compound for sulphate precipitation, similar to the Cost Effective Sulphate Removal (CESR), also known as “Walhalla” process, described in the Montana Tech report (“Demonstration Of Sulfate Removal” 1999), was selected for further consideration [1]. In the CESR process, the water is treated with lime for precipitation of gypsum, followed by the reaction with a proprietary aluminum compound for removal of a residual sulphate. The final pH adjustment is carried out using carbon dioxide. Results of a preliminary cost estimate indicated that the removal of sulphate using calcium hydroxide and aluminum compound was the preferred method of treatment, considering its low cost, availability of chemicals and minimal changes to the existing plant circuit."

Jan 1, 2012

By S. E. Kesler, C. M. Moore, J. C. Van Loon

The possibility that chlorine and fluorine form complexes with ore metals, thereby having a strong effect on the mobility of these ore metals during late magmatic and hydrothermal processes, suggests that the abundance of chlorine and fluorine in igneous rocks could be used to distinguish intrusions that have generated ore deposits. The simplest and most economical measure of this chlorine and fluorine is the water-leachable chloride and fluoride that is released from fluid inclusions in the rock during crushing of the sample. In order to evaluate the possible use of this technique, measurements of water-leachable chloride and fluoride were made with selective ion electrodes on samples from nine intrusive complexes. There does not appear to be any simple relation between the abundance of chloride and the presence of mineralization. Fluoride values in mineralized intrusions appear to be higher than those in barren intrusions.

Jan 1, 1973

By T. Senga, T. Namihira, S. Terada, S. Owada

"Electrical disintegration (ED) has been well known as a good comminution method to improve liberation of compositional phases because it was reported that electron avalanche could occur preferentially at phase boundary. But the detailed mechanism of the ED has been still not known. This paper describes the results of ED experiments using synthetic binary sample, copper/resin, under the conditions of various distance between electrodes, and discusses the energy distribution in the three kinds of phenomena in the ED process, which are(1) streamer progression in water, (2) electron avalanche in water, and (3) electron avalanche in solid sample, by measuring current and voltage with elapsed time. Then, it has been found that the energy distribution in the phenomenon (1) is quite low and that the distribution in the phenomenon(2) had a considerably large compared with that in the(3), which indicates that the shockwave generated in water could contribute much to the sample breakage.INTRODUCTIONElectrical disintegration (ED) has been well known as a specific comminution technology which enhanced selective breakage at phase boundary and lead to a good liberation among compositional phases1-6),but the detailed mechanism has not been clarified yet. This study describes energy distribution among the phenomena in the ED process by using a synthetic binary sample, copper/resin, the phenomena of which are (1) streamer progression in water, (2) electron avalanche and shockwave generation in water and (3) electron avalanche in solid sample usually at phase boundary. The energy distribution could be calculated from ED experiments and from voltage-current changes between electrodes as a function of elapsed time.SAMPLE AND EXPERIMENTALSampleThe sample used in this paper was a synthetic binary solid of copper/resin as shown in Figure1.Cut and polished pure copper lump was put into silicone mold and melted epoxy resin was poured into it and cooled, then, finally the binary sample was polished and molded in the form of 10 mm * 10 mm * 10 mm."

Jan 1, 2017

By S. Kelebek, B. Ingram, C. Gibson, T. MacNeil, M. Aghamirian

"The beneficiation and upgrading of pyrochlore from its ores is carried out through flotation. In industrial practice, upgrading is conducted in a two-stage flotation process in which pyrochlore flotation is carried out after gangue mineral pre-flotation (carbonate, silicate, sulphide or phosphate reverse flotation). In this study, the flotation of pyrochlore from a low grade carbonatite ore was performed at the laboratory scale following a two-stage flotation process in which carbonate minerals were floated in advance of niobium minerals. In parallel, a simplified flotation process was developed in which pyrochlore was floated directly from gangue minerals at increasingly acidic pH. Laboratory results indicated that both two-stage and direct flotation provided similar results in terms of niobium grade-recovery. Based on these results, a large scale, integrated pilot plant was conducted using a direct flotation flowsheet. While the elimination of reverse gangue flotation resulted in flowsheet simplification, the dissolution of carbonate minerals and the subsequent effect of dissolved cations on the floatability of pyrochlore added an element of complexity. A comparison of results from locked-cycle laboratory testing and pilot plant testing highlights the challenges of scaling up a complex flowsheet. A case is made for the direct flotation process and the key parameters to achieving success in large scale direct flotation of pyrochlore are discussed.INTRODUCTIONPyrochlore (Ca,Na)2Nb2O6(OH,F) is a niobium bearing mineral which has been the primary global source of niobium since the first pyrochlore mine commenced operations in the late 1960s (Gibson et al., 2015a). Preceding the discovery and development of high grade pyrochlore deposits in North and South America, the majority of global niobium supply came from gravity concentration operations of columbite (Fe,Mn)Nb2O6, across Africa (Perrault and Manker, 1981)."

Jan 1, 2016