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By N. E. Izatt

Molecular recognition technology (MRT) has a wide range of applications in the hydrometallurgical and chemical processing industries for the selective removal of iron as well as various other impurities from a variety of streams, including aqueous solutions through a wide pH range, as well as organic solutions. An example of a commercial application is provided for the removal of iron from an aluminum chlorohydrate stream. In this example, MRT has a selectivity for iron relative to aluminum which is significantly higher than that of ion exchange resins. A discussion of MRT capabilities for other impurities and streams is also provided.

Jan 1, 2006

By Jacek Paraszczak, Stefan Planeta

"RésuméDans la première partie de cet article on discute Ie contexte technico-économique de l'usage des foreuses à l'eau sur béquille dans des mines sud-africaines. Par la suite on présente les résultats d'une étude comparative du forage avec les foreuses à l'huile et à l'eau par rapport aux foreuses pneumatiques. La performance des foreuses est discutée sous les deux aspects: l'aspect technique concernant Ie taux de pénetration et la quantité d'eau rejetee dans les galeries et l'aspect de fa santé et sécurité au travail, et plus particuliérement, les niveaux de bruit et de vibrations ainsi que Ie brouillard de l'huile. On conclut par l'évaluation du potentiel de forage à I'aide des foreuses hydrauliques dans Ie contexte canadien.AbstractIn the first part of this paper the technical and economical aspects of water-powered drilling are discussed. This technology, originally employed in South Africa, received some interest from Canadian mine operators. In this context a comparative experimental study of pneumatic and hydraulic (oil- and water-powered) jackleg drills has been realized. The performance of the drills is compared and the results reviewed with regards to technical aspects (penetration rate, amount of water spilled) as well as health and safety considerations (noise and vibration level, presence of oil mist). The potential for application of hydraulic jackleg drill is discussed."

Jan 1, 1995

By D. R. Derry

"IT WOULD TAKE a braver man than I to try to forecast the future of mining exploration far into Canada's second century. Even to look ahead ten or twenty-five years we must review the figures of the fairly recent past -and I have found this quite a time-consuming but interesting job -in order to find trends and project them into future years. The trends to which I will refer are: firstly, the annual expenditure on exploration and its relation to value of output; secondly, the discovery rate and its relation to production initiations; and thirdly, the methods by which discoveries have been, and will be, made. Exploration Expenditures Figures on the annual expenditure on mining exploration in Canada have been collected and published for some years by the Do-minion Bureau of Statistics. These have some unavoidable limitations; e.g., in the varying definition between one company and another of what comprises ""Exploration"" and in the difficulty of getting complete returns. However, although the actual figure for a given year may be subject to question, I believe that the relative figures from one year to another are reasonably reliable. There is also a lapse of time between the collection of data and publication -the last published figures are for the year 1963. In bringing the figures up to date to 1966 I have canvassed eight of the larger mining and exploration companies and obtained their figures for 1963 to 1966 inclusive, and then averaged these for each year and applied the progression to the 1963 figures."

Jan 1, 1968

By M. Vallée

"RÉSUMÉDurant les 10 dernières années, les améliorations dans le contrôle des limites des sautages et les arpentages après l’exploitation ont fourni des informations préalables et post facto sur les limites minières réalisées par rapport à la planification, plus particulièrement pour les grands chantiers exploités par les méthodes chambres vides et sous-niveaux. Cependant, peu de recherches ont été faites pour améliorer la délimitation du minerai, l’estimation des ressources et des réserves, les études de faisabilité et la récupération minière dans d’autres types de gisements. Il faudra d’abord expliciter les impacts des lacunes, en quantité et en qualité, de l’information géologique et de l’échantillonnage sur le rendement de l’extraction. Il faudra également remplacer la notion de « dilution générale » par celles de « dilution » et de « perte de minerai ». Les impacts des lacunes observées sur l’exploitation des gisements d’or filoniens sont démontrés par une simulation basée sur des résultats d’études antérieures à la mine Thompson d’Inco, des impacts financiers de densités d’information moindre et par des analyses des valeurs actualisées nettes (VAN) de deux cas types.Deux gisements similaires, de 3 m et 6 m de largeur et exploités par chambres vides sont étudiés, en prenant pour cas de base la délimitation sur maille de 7,5 m (25 pi.) et en étudiant les impacts des limites moins précises supportées par une maille de 15 m (50 pi.), en assumant que ces imprécisions moyennes de +/- 0,62 m se transforment soit en surestimation (dilution), soit en sous-estimation (pertes de minerai).Les impacts d’information moins précise ont été beaucoup plus forts sur le gisement plus étroit : autant la dilution que les pertes de métal ont diminué les VAN du gisement de 3 m de 39,27 % et 45,41 % respectivement, tandis que les VAN du gisement de 6 m ont été diminuées que de 12,84 % et 11,55 %.Ces impacts des valeurs actualisées nettes diminuées justifient et exigent des efforts plus systématiques pour s’assurer que les travaux de mise en valeur et les études de faisabilité soient réalisés de façon requise pour optimiser l’exploitation et offrir aux investisseurs des rendements compétitifs par rapport à ceux des autres secteurs industriels. ABSTRACTDuring the past 10 years, research work to improve the survey of stope limits after mining supplied useful information, particularly for large open and sub-level stopes, regarding waste dilution caused by differences between final production limits and planned stope limits.However, the efficiency of this information to improve the overall efficiency of the mining process is limited, given that the impacts of inaccurate ore limits leading to dilution (sensu stricto) and ore losses have not been considered adequately. Geological/sampling information should be optimized in terms of quantity and/or quality for the deposit characteristics and the constraints of the mining method used. As industry practice regarding the definition and recording of dilution is flexible and as ore losses frequently are poorly documented, the use of these terms is reviewed.Simulations were carried out on two typical narrow gold deposits, based on an earlier study at Inco’s Thompson mine regarding the impacts of wide to narrow delineation grids using recorded variations of vein geometry. Vertical to sub-vertical deposits of 3 m and 6 m widths mined by long-hole open stopes were considered. Deposits delineated by 7.5 m (25 ft) grids were taken as a base case and the impacts of less accurate limits in conjunction with long hole mining based only on a 15 m (50 ft) delineation grid. The impacts of overestimation (dilution) and underestimation (metal losses) were considered separately, using the average error of +/-0.62 m recorded in the Inco study.The impact of less accurate information was much stronger on the narrower deposit: both dilution and ore losses diminished the net present value of the 3 m wide deposit"

Jan 1, 2005

By Cristina Echavarría

MAIN POINTS ? The region: opportunities and limitations ? Overview of main issues emerging from MMSD in South America ? Who comprises the local community? ? What are the main challenges? ? Some suggestions for companies to improve their contribution to local sustainable development of mineral rich localities THE REGIONAL CONTEXT 1. The region is a producer of minerals contributing over 20% to world metal production. It consumes only 8% 2. Significant diversity of national contexts-both between countries and within countries 3. Variable but predominant need for strengthening of government and community institutions and governance, especially at the local level 4. Dearth of baseline information for decision making 5. Sustained social spending during early 90?s as a consequence of economic recovery and fiscal policy, produced important advances in education and health 6. Despite government efforts in most countries poverty continues growing 7. Highly inequitable distribution of wealth persists

May 1, 2002

By Jörg Fischer-Bühner

Conventional 22ct Au jewellery alloys are comparably soft in the as-cast and soft-annealed state and hardening by cold-working is the only way of giving strength to the jewellery. The paper first focuses on hardening of 22ct jewellery alloys by conventional means, i.e. solid solution hardening with base metals (aiming particularly at an increased as-cast hardness) as well as precipitation hardening by alloying with base metals beyond the solubility limits and subsequent age-hardening heat treatment. Co-additions of ~2% turned out to result in most pronounced solid solution hardening up to ~100 HV1 in an investment cast & quenched state. Subsequent heat treatments, consisting of solution annealing at 850°C for 1h followed by water quenching and ageing at 300°C ? 400°C for ~ 1h lead to pronounced age-hardening with a peak hardness of ~ 260 HV1. In contrast, 22ct Au alloyed with Ni, Fe or Sb display no age-hardening effect within the same range of heat treatment parameters. The 2nd part of the paper reports on some preliminary trials to enhance the hardening effect of the base metals by additions of suitable elements, which possess a strong tendency to phase formation with the added base metal during ageing treatments. It is shown, that the age-hardening behavior of 22ct and 990/995 Au alloyed with Co or Ni can be remarkably influenced by additions of Sb. A total of only 10wt%0 of CoSb or NiSb-additions lead to a peak hardness of ~ 150 HV1 for a 22ct Au and ~ 100-120 HV1 for 990 Au , which is obtained already after very short ageing times (20-40min) at 300-400°C after solution annealing at 700°C / 1h / water quenching. It is suggested that the age-hardening mechanism in these alloys consists in precipitation of intermetallic CoSb- and NiSb-phases.

Oct 1, 2003

By Bennett McLaughlin

The Penna Shaft is the deepest single?lift shaft in North America. AGNICO-EAGLE started sinking the Penna shaft in 1995 with a hoisting plant capable of hoisting 1 800 tonnes per day from a 2 240-metre deep shaft. Exploration success at depth lead to the replacement of the existing double drum hoist by another double drum hoist capable of hoisting 7 000 tonnes per day. The use of another double drum hoist, instead of a Blair Multi-Rope winder, to hoist 24,5-tonne skips was only made possible by lowering the safety factor. This paper describes recent experiences at Penna and in South Africa, and examines the possibility of extending the double drum hoisting system to a depth of three kilometres.

May 1, 2003

By Salvador Gómez, Rodolfo Espinosa, Jaime Bravo, Leopoldo Gallas

"Compañia Fresnillo, S.A. de C.V. - Proaño Mine, is owned by Industrias Peñoles S.A. de C.V. (Peñoles). The Proaño Mine, is one of the richest silver underground mines in the World, and for this reason, production capacity has always being expanded, based on generated reserves. Reserve generation has not being an easy task as this is a vein type deposit.This paper presents the growing stages at the Concentrator, for about the last twenty years; which can be listed as follows:1.,Increase in capacity from 1,000 to 4,500 tonnes per day, at several stages; on the same infrastructure, and without production interruptions.2.,Addition of a new flotation circuit to recover a zinc concentrate with a high silver content.3.,Installation of a semi-autogenous (SAG) mill, to replace a conventional crushing circuit. 4.,Modernization. Installation of an on stream analyser, an automatic reagent dosification system, 4500 ft3 unit cells, pressure filtration, a closed circuit video system to help process monitoring, an automatic ball addition system for SAG and ball mills, and on-line particle size analysers.5.,Silver recovery from old tailings, installing a 2,350 tonne per day treatment plant.INTRODUCTIONIndustrias Peñoles, S.A. de C.V. (Peñoles)Peñoles’ mission is to add sustainable value to non-renewable natural resources. Peñoles seeks to: build long-term shareholder value; provide customers with the highest quality product services; maintain productive long-term relationship with suppliers; develop and promote the capabilities of their personnel; foster mutually beneficial relationship with the communities in which operates; protect and preserve the environment."

Jan 1, 2002

By Richard Frentress, Dave Donelon, Robert Henderson, Mike Warnert

"The Round Mountain gold mine is an open-pit mining operation located 97 kilometres north of Tonopah in Nye County, Nevada. Gold has been produced from the property since 1906.Gold is currently recovered using a combination of four independent processing operations. These include a 10,000 ton per day mill, a 30,000 ton per day, crushed ore heap leach, a 150,000 ton per day, run-of-mine ore heap leach and a small high-grade gravity concentration circuit. In 2002, Round Mountain Gold Corporation produced 755,494 troy ounces of gold at a total direct operating cost of US$2.14 per ton ($193/oz).This paper presents a summary of the Round Mountain operations and discusses some of the processing innovations that have enabled the mine to profitably recover gold from a large low-grade ore body.INTRODUCTIONRound Mountain Gold Corporation is a 50/50 joint venture between Kinross Gold Corporation and Barrick Gold Corporation. Kinross acquired its ownership interest in the Round Mountain mine upon completion of combination with Echo Bay on January 31, 2003. The joint venture partners continue to support an aggressive exploration program in the vicinity of the mine in order to add reserves and extend the mine life.The Round Mountain mine currently operates a conventional open pit that is approximately 8,200 feet long, 4,900 feet wide and 980 feet deep. Mining is conducted on 34-metre benches by electric shovels and front-end loaders paired with 150, 190 and 240-ton haul trucks. Blasthole samples are collected and assayed and provide the control for ore segregation. Based upon these assays, blasted pit rock is determined to be run-of-mine Dedicated Pad ore, crushed Reusable Pad ore, high-grade ore or waste.Gold is recovered using a combination of four independent processing operations. These include run-of-mine ore heap leaching (Dedicated Pad), crushed ore heap leaching (Reusable Pad), milling and the gravity concentration circuit. Non-mineralised rock is delivered directly to the waste dumps. Low-grade ore is trucked directly to the Dedicated Pad and medium-grade ore is crushed and placed on the Reusable Pad. High-grade ore is handled in one of three ways: 1) leached on the Reusable Pad and offloaded to the mill; 2) sent directly to the gravity plant with tails reporting to the mill; or 3) sent directly to the mill or mill stockpile. The gold particle size distribution of highgrade ore determines the processing method."

Jan 1, 2005

By M. Maldonado

This work details the application of a decentralized control strategy to a pilot flotation column working with a two-phase system (water-air). The process is represented by a multivariable system composed of three inputs and three outputs. The selected control variables are the froth depth, the air hold-up and the bias rate, whereas the corresponding manipulated variables are the set-points of the local flow controllers of tailings, air and wash water. All controlled variables are estimated using electrical conductivity based techniques. In particular, the results of a new method for estimating the bias rate, based on the measurement of the volumetric fraction of wash water under the interface, is presented. This method reduces the coupling problem associated to the bias estimation as a difference between feed and tailing water rates. Moreover, the nominal system transfer matrix can be represented by an upper triangular matrix, in such a way that the closed-loop system stability reduces to the stability of the independent control loops. The experimental results show that the closed-loop system performance, particularly that of the bias rate loop, is strongly dependent on the air flow rate, reaching in some cases the saturation point of the controller.

Jan 1, 2007

By Chen Xia, G. Deschenes, Wan-Tai Yen

"Ammonium thiosulphate is a potential replacement for the cyanide in gold leaching. However, the high reagent consumption hinders its practical applications. In order to reduce the thiosulphate consumption, chemical additives were used. The gold leaching tests were conducted on a sulphide copper-bearing gold ore with 0.3M thiosulphate, 0.03M copper sulphate and 3M ammonium hydroxide solution at 44% solids and pH 10.2. Sulphate, sulphite, amino acid and chelating agents were initially used as additives. It was found that chelating agents (EDTA and NTA) could reduce the thiosulphate consumption from 30 kg/t to 17.8 kg/t with some increase of gold extraction. The improvement from other additives was not significant. Other approaches were also attempted to reduce thiosulphate consumption with some success. The thiosulphate consumption could be reduced to about 17 kg/t by reducing copper sulphate concentration fiom 0.03M to 0.0015M; adding 0.04M of EDTA; replacing copper sulphate with 0.001M of nickel sulphate. The increase of pulp density fkom 44% to 60% solids could reduce the thiosulphate consumption to 17 kg/t as well. Limiting the dissolved oxygen content by sparging nitrogen reduced the thiosulphate consumption further to 10 kg/t. It could be concluded that the regulations of copper and oxygen supply in the lixiviant were the keys to reduce the reagent consumption.INTRODUCTIONCyanidation, as the predominant gold leaching method, has been used in mining industry for more than a century. The low reagent requirement and the high performance are the reasons for its great success. However, cyanidation cannot deal with ores containing large amount of copper, nickel, arsenic and zinc minerals. This type of ore may consume more reagents and result in a poor gold extraction. On the other hand, the carbonaceous materials may preg-rob the gold from pregnant solution and make cyanidation a problem leaching method. Further more, the high toxicity of cyanide represents another challenge to modern gold mines. In the beginning of the year 2000, an environmental disaster caused by an accidental spill in Yugoslavia was broadcasted world-widely (Gurevitch 2000). Gold mine operators are facing higher social pressures and increasing costs on environmental protections. The usage of cyanide in mining industry has been banned in some countries and locations such as Czech Republic, Japan, Turkey, California, Colorado, Wisconsin and Montana States. Thus, a non-cyanide lixiviant is required."

Jan 1, 2002

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By Todd S. Harris

"IntroductionThe western region of North America has long been considered a dynamic market supporting such diversified industries as lumber, agriculture, cement, and electronics. In recent years however, the region has also been the focus of a great deal of activity in the extender and filler mineral s business from companies seeking to position themselves to take advantage of the large demand for these materials both here and abroad.Extender and Filler MineralsExtender and filler mineral s include 15different products used in numerous end uses. The nine most important extenders and fillers are listed in Table I. These products range in price from under $50 a ton to over $4,000 a ton and basically represent the following three different types of minerals:Particulate products-Calcium carbonate; Kaolin; Silica.Platy minerals-Talc (Montana, Canada); Mica.Fibrous minerals-Talc (California, Eastern U.S .A.);Wollastonite.What distinguishes these products from other industrial minerals? For one thing, an important feature of extender and filler minerals is that they are used primarily in such consumer non-durable good s as paper, paint, plastics, sealants, and rubber which traditionally do not react as violently to swings in the economic cycle. In addition, these minerals are sold principally on key physical properties, usually brightness, particle size and shape, oil absorption, and hardness. As part of the physical minerals segment of industrial minerals, extenders and fillers are traditionally the most stable group and typically the most profitable. Studies by C.H. Kline over the past decade on extender and filler minerals has revealed historic average profitability (expressed as a percentage on sales) nearly double that of most other industrial mineral s.The demand for these minerals in the western region (Fig. 1), closely follow s the areas of greatest population concentration. These markets include pulp and paper, mainly in the Pacific Northwest, and paint, around Los Angeles and San Fran cisco. Other significant markets for extender and filler minerals in western North America include joint cements, carpet backing, and plastics, mainly PVC pipe."

Jan 1, 1986

By Ertugrul Alp

Alp & Associates - Who We Are ?? Canadian consulting company (1999-?) ?? Principal Consultant: Dr. Ertugrul Alp, P.Eng. ?? Over twenty-five years experience serving the chemical, mining, pulp & paper, energy, steel, and transportation industries, and government clients. ?? Ph.D. in Mechanical Engineering, University of Waterloo ?? Experience: ?? Westinghouse Canada, Atomic Power Division, Manager, Analysis and Modelling ?? Concord Environmental (later Bovar Environmental), Principal, Manager, Air Quality and Risk Assessment ?? Arthur D. Little, Associate Director, Safety & Risk Practice Leader in Canada ?? Member: NATO CCMS Pilot Project on Disaster Preparedness (1991-1993) ?? Chair: MIACC Risk Assessment Expert Committee, 1995-1999 ?? Member: MIACC Committees on Land Use Planning and Pipelines (1993-1998) ?? Member: CSA/Q850 Risk Management Standard Technical Committee ?? Member: CSA/Z1002 OHS Risk Assessment Standard Technical Committee ?? Member: CCPA/CSChE Process Safety Management Committee (1999-?) ?? Member: ISO-31000 Risk Management Standard Canadian Advisory Committee ?? Chair: CSChE Process Safety Management Committee (2005-2006) ?? Chair: CSChE Expert Committee on Risk Assessment (1999-2005) ?? CSChE 2007 Process Safety Management Award

May 1, 2008

"3.1. IntroductionAmong the six platinum-group elements (POE), four have identical cubic symmetry, two identical hexagonal symmetry (Table 3.1). Despite crystallographic differences, there is a clear relationship expressed in the chemistries of the POE: they tend to be mutually soluble in one another and can frequently substitute for one another in compounds with other elements. This chapter consolidates the data on phase relations of the POE and the compounds they form with elements selected for their known or potentially important mineralogical significance- As, Bi, Cu, Fe, Hg, In, Ni, Pb, S, Sb, Se, Sn and Te-together with selected data for the occurrence of POE in certain elements such as Au and Ag, and compounds such as FeS. Resources used to compile the data are those available from the chemical, mineralogical and metallurgical literature. First each element is discussed, with composition limits of solid solutions drawn from binary phase diagrams. Single element data are followed by a discussion of the relevant binary systems and a tabulation of data for binary compounds found in those systems (Table 3.2). Tables and diagrams for the ternary and quaternary systems for which information is available follow, and finally the very limited information on the solubility of POE in mineralogically important elements and compounds is presented.The chemical, mineralogical and metallurgical literature on the unary and binary systems is extensive and widely scattered in many languages and publications; fortunately, most of the data needed to compile this chapter can be found in reliable compendia. The most useful and most recent of these works is by Moffatt (1979), because it provides a ready index to all material relating to binary systems listed in previous compendia; furthermore, the Moffatt compendium will reportably be kept up to date by annual supplements."

Jan 1, 1979

By R. Sharon, P. M. Hawley, X. Ochoa

"Development of Barrick Gold’s Pierina gold mine in north-central Peru requires construction of a waste dump for disposal of nonore grade materials stripped from the open pit to expose the ore. The waste dump site is located near the open pit in a U-shaped valley that is underlain by thin colluvial and morainal soils with locally thick peats and glaciolacustrine deposits. Bedrock underlying the site consists of variably weathered volcanics. The site is subject to moderately high seasonal rainfall and significant seismicity. The geotechnical quality of the waste rock is highly variable, ranging from low-quality, degradable, soil-like materials containing appreciable quantities of silt and clay, to high-quality, hard, durable, blocky waste rock.A hybrid dump design concept was developed that requires in-pit segregation of highand low-quality waste, and selective placement of materials in the dump to maximize stability and enhance internal and subsurface drainage. The design includes a rock drain beneath the dump along the axis of the valley and a series of connected finger drains. Extensive peripheral diversions and stormwater control measures to inhibit infiltration of precipitation are also included.This paper discusses the unique challenges presented by the site and waste materials, the design methodology and stability analyses, and planned monitoring systems."

Jan 1, 2003

By Graham A. Davis, Michael Samis

The dramatic fluctuation in metal and energy prices in the last few years is causing mining companies to consider alternative analytical methods for mine design and valuation. The goal is to improve insight into unforeseen changes in the economic and project environment and to design projects that take advantage of management's ability to respond to these changes. Such flexibly managed projects will contain value that cannot be measured using traditional engineering economic approaches, further motivating the used of alternative, modern valuation methods. This paper considers the valuation of an uneconomic low-grade resource at an open pit gold mine using two of the most popular modern valuation methods, Dynamic Discounted Cash Flow and Real Options. Our analysis demonstrates that the conventional valuation method may incorrectly represent the value and risk attached to mining this type of resource because it is unable to recognize management's ability to respond to future events in a manner that minimizes losses and exploits advantageous business conditions. The results of this paper highlight the importance of recognizing flexibility and business uncertainty in both mine design and valuation.

Jan 1, 2003

By G. Bonin, R. P. Preston

"This paper presents a series of case studies where spherical camera photographs were used to generate 3D shaft models using photogrammetric methods. The shaft models were, checked for accuracy by comparing them to overlapping laser scan data, provided survey data or idealized shaft models. Short lengths of model were found to more accurately reproduce the shaft surface, with a best observed accuracy of 8 mm. Longer models encountered errors with accumulated errors as exhibited by slight deviations from vertical or slightly conical model shape. At present, the models are considered acceptable for general documentation and gross change detection. INTRODUCTION Shaft inspections are required by mining regulations in many jurisdictions and are commonly completed by trained mine personnel via visual inspections. This can be time consuming and prone to errors due to lapses in attention and the rapid travel rate required to inspect an entire shaft in a reasonable amount of time. Similarly, because of the time requirements, there can be impacts on other aspects of mining as a result of occupying the shaft for inspections. Spherical cameras with supplemental light systems offer a modern addition or alternative to conventional inspections. These cameras can be lowered relatively quickly to collect high definition, fully illuminated videos of the shaft that can be reviewed in detail later while the shaft returns to service (Gillis et.al., 2019). The use of cameras offers a further opportunity for valuable survey data generation from the same original data stream. The video data can be processed into three-dimensional (3D) models using Structure-from-Motion (Westoby et al., 2012) based photogrammetric methods. Depending on the quality of the source video and availability of survey control (required for all photogrammetry models) these models can be very accurate. Shaft surveying can be conducted with traditional theodolite methods but such surveys are time consuming and limited in their data density. Similarly, scans can be completed using conventional terrestrial laser scanners, but this requires a significant number of distinct setups to provide sufficient overlap between scans. Work is being conducted both on the laser scanning (SLAM, Durrant-Whyte & Bailey, 2006) and photogrammetry fronts towards kinetic scanning (Benecke, 2017) systems. The major advancement which is permitting these kinetic systems is Inertial Measurement Units (IMUs) which can provide localization in GPS denied environments and reduce errors associated with the open traverse format associated with shaft scanning."

Jan 1, 2019

By Jose R. Hernandez-Aguilar, Jeet Basi

"The study evaluated the impact on overall circuit metallurgy of improving the performance of the two flotation columns that make up the final Mo cleaning stage in the Cu/Mo separation circuit at Highland Valley Copper mine. The results showed that a key factor to improve the overall circuit metallurgy was to control the size of the bubbles generated in the columns. When a large proportion of small (< 1 mm) bubbles were generated, the production rate of solids-in-concentrate increased by a factor of 4-5 compared to typical production figures without compromising concentrate quality. This increase in concentrate production rate reduced the circulating load in the circuit causing a significant increase of Mo recovery. A statistical analysis of historical production data showed a strong relationship between final concentrate production rate and overall Mo recovery. This relationship along with the results from this study indicated an opportunity to increase the recovery of Mo from 90% (typical) to 94% without downgrading concentrate grade. This 4% increase represents about 14,000 lbs or $500,000 worth of Mo each month at current metal prices.To provide a rational interpretation of the results, this study also examined whether the model of Gorain et al. (1997; 1998; 1999) could explain the increase of Mo recovery seemingly resulting from the decrease of bubble size. The data showed that the model predictions did not agree with the experimental data, i.e., for a given change (decrease) of bubble size, the predictions underestimated significantly the observed recovery increase. An interpretation based on the fundamental analysis of Finch and Dobby (1990) and Hernandez-Aguilar et al. (2005) is proposed to explain the discrepancy between measurements and predictions obtained from Gorain et al.’s model.INTRODUCTIONIt is generally accepted that the size of the bubbles generated in a flotation cell – a concept usually referred to as “bubble size” – has a significant effect on metallurgical performance. However, a significant number of mineral processing practitioners often question, with valid reasons, the practical benefits of implementing process improvement strategies based on controlling bubble size. “Small” bubbles are often considered to be “favourable”, but how small they need to be for a particular case, or how to adjust operating conditions to control a target bubble size, or whether the bubbles need to be smaller in the first place are questions that usually remain unanswered. Two reasons explain this situation."

Jan 1, 2009

By Kyle Selga, Christopher J. Greet

"The Pulp Chemistry Monitor (PCM) has been installed and operated in a number of concentrators in Australasia, and has produced some very interesting results. PCM measures the pH, Eh, dissolved oxygen, temperature and oxygen demand of process streams within a concentrator continuously and in real time.In the example presented in the paper the cleaner feed pulp chemistry is measured, and related back to changes in the mineralogy as well as variations in metallurgical response. For example, a decrease in Eh and dissolved oxygen as well as an increase in the oxygen demand. These changes in the pulp chemistry appear to coincide with increases in the feed grades, probably higher pyrite grades. Further, these variations in pulp chemistry and feed mineralogy have a negative impact on the concentrate grade and recovery.The implication is that if the pulp chemistry is monitored it is possible to predict changes in the mineralogy of the system, and from this the metallurgical response. Further, the changes in pulp chemistry can be used in a control system to counter the changes in mineralogy and maintain the metallurgy.IntroductionIt has long been recognized at a fundamental level that the flotation behaviour of sulphide minerals is dependent on the pH and Eh of the system (for example: Tolun and Kitchener, 1964; Woods, 1976). However, measuring pulp chemical parameters within an operating concentrator has had limited attention. Woodcock and Jones (1970a and b) were among the first to actually collect data from operating plants. Jones and Woodcock (1984) identified some of the chemical complexities of flotation pulps, and noted that most concentrators already operate at high levels of metallurgical performance but there was still considerable scope for improvement. These gains would, in part come from more effective chemical control. In the same volume, Healy (1984) discussed metal ion hydrolysis and precipitation, redox chemistry and how the surface chemistry of sulphide minerals can be influence flotation behaviour. The impact of grinding environment on the pulp chemistry and flotation response of a complex polymetallic sulphide ore is discussed by Forssberg and Subrahmanyam (1993). Their work essentially contrasts the pulp chemical and flotation performance of pulps ground with conventional ferrous grinding media to a fully autogenous system. The data suggested that the reduction or removal of iron hydrolysis contamination from the system could have a positive influence on flotation behaviour, and perhaps the first stage of “controlling” the chemistry of the system should be in the grinding circuit. Grano et al (1995) demonstrated that the collection of pulp, solution and surface chemical data could identify weaknesses within a concentrator, and from these data develop, test and implement solutions that improved the process. Greet et al (2006) showed that the pulp chemical trends observed through primary grinding and rougher flotation circuits of most sulphide flotation concentrators are approximately the same. There are differences in the magnitude of various pulp chemical parameters (pH, Eh, dissolved oxygen, temperature and oxygen demand) as a result of variations in the feed mineralogy and processes employed. Further, it was noted the Eh shifted to more reducing values of the ten days measurements were collected, and this change could be traced to an increase in the iron sulphide content of the feed. Metallurgically, this resulted in an increase in nickel recovery through the recovery of nickeliferous iron sulphides, and a decrease in nickel concentrate grade."

Jan 1, 2016