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By D. Kidby, A. Briggs

"Vitrokele ™ is a synthetic adsorbent, using chelating groups on large polystyrene beads, developed in Canada over 7 years ago, and first commercialised in 1985 to recover noxious metals from plating wastes.Pilot plant trials have been performed in Australia and Canada to demonstrate the recovery of cyanide and removal of metal cyanide complexes from gold plant effluent using Vitrokele1 M 912. The pilot plants comprise a simple adsorption train (similar to a CIP circuit) followed by complete elution facilities, so that loaded Vitrokele™ can be stripped and returned to the adsorption circuit.An account of these campaigns is provided, showing the reduction of total CN levels from over 200 ppm to less than 0.5 ppm and Cu levels from approximately 100 ppm to less than 0.3 ppm in treated tailings.Comparisons between pilot plant results and laboratory test data are given and probable future work on the process and its application to the gold mining industry is discussed.INTRODUCTIONThrough millions of years of evolution, life forms have developed specialised molecules with exceptionally high affinity and selectivity for various metals such as iron, cobalt, zinc and copper.In the early 80's professors at the Faculty of Medicine of McGill University engaged in research on the extremely efficient ways that living cells captured trace metals essential for life.As research progressed, it became evident that the special molecules used by biological systems to capture metals could be synthesized to capture selected metals with similar efficiency from water or other solutions.The technology was first commercialised in 1985 to recover noxious metals from plating wastes with compositions applying the special molecules (chelating groups) on vitreous particles (hence Vitrokele™). To date approximately three commercial Vitrokele™ plants have been installed for treating plating waters in Ontario and Quebec."

Jan 1, 1992

By R. E. McElvain

"Hydraulic transportation of solids in suspension with water or other carriers, such as oil is becoming more practical as economic situations develop with respect to the railroads and other carriers. Of significant importance, is also the increased size of the major operations and the total impact of larg- er tonnages and more critical sources of supply.There are several means of imparting energy into the solids and directing the material down a pipeline, but the centrifugal pump is emerging as the most practical piece of equipment when considering relatively large flows and recent development. We can now handle relatively high densities without interruptions. This provides the mining and transportation fields a more economical means of lifting and transporting coal and other mineral products.Equipment & MethodsWarman International has developed several methods of alternate PDP against high heads. We have, at least for the present time, shelved our pump which uses clear water to slurry method and have placed our major emphasis on the full development of the centrifugal pump. I personally see several similarities on the alternate reciprocating devices as compared with the steam piston type engine versus steam turbines. The centrifugal pump comes into its most advantageous position at about 2000 GPM and can also show advantages by means of increased mobility, when driving tunnels and in other difficult operations when considering the total economic results. We now have some interesting d<:ta on one 5 mile raw silica sand line designed for pumping at 200-400 tons per h:mr. This is a separate subject on a ""simplified approach to slurry transport"" and paper has been prepared for the Hydrotransport 5 proceedings in Germany this Spring. Reference 1 may be of interest to those who want to delve into the subject further, and I also have some advance copies of this paper."

Jan 1, 1978

PERSPECTIVE ?Natural resources exploration, extraction and beneficiation is complex and challenging: ?Input costs rising, complexity increasing, rising stakeholder management needs, regulatory compliance issue, etc. ?With increasing costs and complexity of managing operations are we simply getting less bang for our buck?

May 1, 2013

By P. D. R. Maltby

This paper describes the background and markets for calcium carbonate and silica sand in Canada, as well as the results of recent test work carried out at the Ontario Research Foundation. Tests on sericite, tremolite, vermiculite, barite and graphite are also mentioned.

Jan 1, 1979

By Bevan. P. A.

The general location, topography and climate are discussed briefly, together with an historical record of the deposit. General geology, grade control and ore reserves are covered at some length, and reasons are given for the operation being placed on a salvage basis.

Jan 1, 1973

By L. D. Smith

"Those who submit competing proposals for projects seek to present senior management with complete and fully supported material that will not fail under questioning. Hopefully, misleading notions and omissions will have been minimized and there will have been testing of the assumptions regarding the economic, social and political environments. A capital project evaluation team can do management and itself a service by including a sound approach to the impact of inflation (and its twin problem, interest) on a project and a great disservice with an inappropriate approach to inflation.InflationHandled deftly, inflation can alter a project evaluation to show almost any result the handler desires. It must be a constant source of frustration for design people and cost estimators to spend weeks perfecting the technical aspects of a project in order to minimize costs, only to have all of their efforts set awash in a sea of financial and economic assumptions that submerge all of the detail. In all of this, inflation is perhaps the largest offender, with inflation criteria often being brought to bear at the last minute, almost as an afterthought. Perhaps this tardiness reflects the difficulty of the subject and the belief that senior management will take its own approach to the problems of inflation. Such a belief is unfair to senior management, for it is entitled to not being misled by omission. It is entitled to the full use of the skills of the evaluating team, including respectable assumptions of the impact of inflation.Working in a consulting context, one has the opportunity to participate in the evaluation of a large number of projects. Reflecting the observation of a wide range of views regarding the subject of inflation, this paper will-address the impact of five different approaches to inflation on the evaluation of a single Canadian mining project."

Jan 1, 1987

By L. Mohammadi

Outline ?Background on the accident at the Sullivan Mine No.1 Waste Dump ?Holistic approach to understand the reason for accidents (Atmospheric) ?Specific hazards at reclamation sites ?Regular atmospheric risk assessment at reclamation sites ?Fuzzy risk assessment ?Managing risk at legacy sites

May 1, 2010

By C. F. Gleeson, D. G. Sheehan

"The results of humus and overburden geochemical surveys over the Doyon, Bousquet and Page-Williams gold ore deposits are presented.These studies show that humus sampling for gold gives negative results over the Doyon deposit. The lack of response is probably caused by the presence of 1 m of relatively impermeable glaciolacustrine clay and silt that overlies 1 m to 2 m of till over the surface expression of the ore zone. By contrast, positive responses for gold occur in humus samples over the Page Williams A and C gold deposits. The ""A"" ore zone is covered by several metres of exotic calcareous till over 0.5 m to 1 m of older, locally derived till. Anomalous values for gold in humus range from 10 to 35 ppb over the orebody. Overburden over the ""C"" ore zones is much thinner, generally it consists of less than 2 m of sandy till. Trenching humus anomalies that range from 10 to 1360ppb Au uncovered the gold mineralization. The geochemical dispersal trains in till from the Doyon orebody and the Page-Williams ""A"" zone are relatively short (i.e. less than 200 m) because both deposits occur in the lee of bedrock highs that shielded them from extensive glacial quarrying. Dispersal trains from all three pyritic gold deposits can be defined using either the fine fraction or heavy mineral fraction of the till.The intensity of the gold in till anomalies over the ore zones is variable. Therefore, it would be misleading to attach rigid significant threshold gold values to overburden drilling results. Each case must be evaluated based on bedrock topography, sample density, overburden type, thickness of till, as well as size, type and orientation of the target exposed to glacial erosion."

Jan 1, 1987

By Earle J. Klohn

"The design, construction and operation of tailings dams is rapidly becoming a major consideration for most new mining developments, as well as for many existing operations. In North America, under pressure from public opinion, various government agencies have in recent years enacted legislation covering the design, construction and operation of tailings dams. In British Columbia, comprehensive legislation has been passed during the past year (1971). All of these new regulations may be placed into two broad categories: regulations concerning the safety of the dam and appurtenant structures, and regulations concerning the prevention of pollution. Both types of regulation affect the design of the tailings dam facilities. Consequently, they must be considered jointly by the designer. A good tailings dam design must satisfy the basic requirements of safety, pollution control, storage capacity and economy. To achieve this, 'the design must be based on a thorough understanding of both the geotechnical problems involved and the requirements of the mining development. Obviously, this requires close cooperation between the designing geotechnical engineers and the mining operators. This paper outlines the major engineering factors that should be considered in the investigation, design, construct ion and operation of tailings dams. Basic methods of tailings dam construction are reviewed and the advantages and disadvantages of each briefly discussed. Comparisons are made between the design and construction of conventional water supply dams and tailings dams. Examples are presented of some of the problems that may arise during construction and operation of a tailings dam. The paper also explains the need for basic instrumentation of tailings dams and for carrying out simple field tests and measurements during construction and operation. Of prime importance is the downstream monitoring of surface and subsurface seepage flows. These observations are invaluable where contamination of surface and/or subsurface water may become a contentious issue at some future date. Each tailings dam design must be based on a study of the particular requirements of that project. To make a proper evaluation, adequate data must be available concerning a large number of items•, including such things as: topography, hydrology, geology, subsoil properties, seismicity, government regulations, fineness of mill grind, mill water balance, availability of suitable construction materials, volume of water to be stored behind starter dam, downstream development or liability, and many others. The large number of variables involved in such an evaluation often result in the designer considering two or more alternative designs. Selection of the final design, which is usually based on detailed cost analyses of the alternatives, must be made in close consultation with the owner."

Jan 1, 1972

By A. S. Baillie

THE subject of taxes appears to engage our attention altogether too lightly. At least it would seem that, notwithstanding the increase in the cost of government, and its concomitant increased taxation, little constructive work is being done with a view to solving the problem of increased taxes. I believe that the inattention of the public generally to the subject of increased taxation is due largely to the fact that shareholders are not advised of the amount of taxes paid by industry. Were companies to advise their shareholders the amount of monies paid or payable out of each year&apos;s earnings for taxes in one form or another, and were such amounts compared with the amounts available for distribution to shareholders, the effect would be a general demand for more equitable taxation methods. While I am not unmindful of the burdens and inequities in taxation confronting industry generally, I believe that the mining industry in this Province does not fully appreciate the burden represented by the costs of taxation. My reason for this belief is based partly upon1the fact that no serious effort has so far been made to devise some means By which the mining industry in British Columbia might protect itself against the ever-increasing burden of taxation. In addition to this fact the widely diverse nature of mining in British Columbia makes the accumulation of comparable data a problem which, so far as I can ascertain, has never been attempted in a manner which would be authoritative. It should not be necessary to cite the effects of this burden upon any one mining company or upon any branch of the mining industry, such as coal mining, placer mining, base-metal mining, or the precious-metal mines. In my opinion, the operation of our mines by large corporations is conducive to the payment of taxes with much less protest than would be the case were the taxes being taken out of the earnings of just a few partners or a very few shareholders. We appear to be too unmindful of the taxes, paid by mining companies, of a kind that are not so prominently brought to our attention as are the taxes which are calculated upon the taxable income of the company at the end of its fiscal year. British Columbian mining companies pay many other taxes besides those which are calculated upon taxable income. Among these are school taxes, property taxes, gasoline taxes, mineral taxes, coal royalty, to say nothing of fuel-oil tax, sales tax, and excise taxes.

Jan 1, 1935

By A. E. Flynn

THERE is at the present time a revived interest in amalgamation, due to the number of mines starting up, usually on high-grade ore, and utilizing this relatively cheap and convenient means of recovering gold, more especially in their initial stages of production. The marked increased use of the amalgamation process has revealed a dearth of amalgamators and there is no doubt the art of amalgamation has stood still for a generation or two and is not readily applicable to the modern practice of milling gold ores. Mill operators of long experience are learning the art for the first time and are giving it intelligent study, and considerable testing and research work is now being undertaken Most millmen consider amalgamation a simple process, and so it is when we have a clean ore with coarse gold, specially when stamps are used for crushing. In treating Nova Scotia ores by stamps and amalgamation, recoveries of 95 to 97 per cent are common and easily obtained. So-called &apos;under-water feed&apos; is almost universally used in Nova Scotia and is quite beneficial. The water is supplied through jets between the dies and below the die surface and maintains this space as a live trap which catches the gold particles before they are overground and spoilt for amalgamation. With this method, the portion of gold recovered in the battery is higher than usual and often amounts to 80 per cent of the total gold in the ore, the remaining 20 per cent being caught on the plate. As a continuous amalgamator, the simple plate cannot be excelled. Some of the modern devices having moving or covered and not very accessible plates, which cannot be readily inspected and dressed to keep them in condition, do not give the best results in service. An exception might be drawn in the case of amalgamation of very heavy ore or concentrate which would bank up unless the plate is carried at such a steep inclination as to weep mercury. Difficulties in stamp-mill amalgamation are encountered when acid water is used or when grease is present. Also, certain sulphides and graphitic and talcose ores give trouble, resulting in poor gold recovery and high mer-cury loss. The older literature on gold milling deals with the common troubles of this type and the old-time amalgamator was well able to take care of day-by-day difficulties. When the difficulties were unsurmountable, the ore was classed as &apos;refractory&apos; and other processes were used.

Jan 1, 1939

By M. C. Harris

"Excess Gibbs energy is a thermodynamic parameter which quantifies the difference between the value of the Gibbs energy for a real mixture and that for an ideal mixture. More specifically the partial molar excess Gibbs energy of a species (i) in a mixture is indicated by the change in the overall excess Gibbs energy of the solution as the number of moles of species (i) changes while keeping temperature, pressure and the number of moles of all other species in the solution constant. Generally it is obtained from the activity coefficient which in turn can be obtained for a species in a mixture using a variety of models. The most widely used method is to use UNIFAC. Flotation is probably the most important process in the concentration of minerals and requires the use of reagents such as collectors and frothers. There is abundant experimental data which illustrates that collectors of different alkyl chain lengths will change the contact angle and that frothers of different structures and molecular weights will result in changes in key flotation properties such as froth behavior, surface tension and critical coalescence concentration. In this paper it is shown that there is a strong linear relationship between measured parameters such as froth volume/height, surface tension, critical coalescence concentration and contact angle and the partial molar excess Gibbs energy of the molecules used. Proposals are made to explain these correlations.INTRODUCTIONAs is well known froth flotation is arguably the most widely used process in the separation of minerals. In broad terms the process relies on the use of reagents known as collectors to adsorb onto a mineral surface and thus render the mineral particle hydrophobic. Alkyl thiolates are very commonly used for this purpose. The hydrophobicity is induced as a result of the alkyl group’s molecular structural properties which results in it forming a non-ideal mixture with the process water. Surfactants (or frothers) are typically alcohols and are known to lower the surface tension of the system and also inhibit bubble coalescence and reduce bubble size. Since alcohols are polar they will also form a non-ideal mixture with water. The hydrophobic mineral attaches to the bubble and rises to the froth phase where the valuable mineral is recovered as a concentrate. Frothers have often been characterized using the so-called HLB (hydrophobic-lipophilic balance) number but recently it was shown that the use of activity coefficients (?) or excess Gibbs energy (G ex ), which is calculated using equation (1) is a much more appropriate way to describe the behavior of these reagents in non-ideal mixtures with water (Corin and O’Connor, 2014)."

Jan 1, 2016

By K. E. Waters, M. Mirnezami, R. Gauvin, A. Jordens, K. W. Malas

"There is currently very little information on the physico-chemical properties of rare earth elementbearing minerals, or on their processing. With the increasing demand for rare earths, this is something that needs to be addressed. This paper introduces some surface chemistry analysis of fergusonite (YNbO4), and the bubble-particle attachment. Zeta potential measurements indicate adsorption of sodium oleate and, to a lesser degree, potassium amyl xanthate onto the surface, and an increase in attachment to an air bubble is observed at pH 4.5 and 6.5. At a pH of 10.5, no attachment is observed, whether in the presence of the reagents or not. This analysis, although initial, will be used to initiate flotation tests, in order to facilitate the selective recovery of fergusonite. INTRODUCTIONRare earth elements (REE) are increasingly in demand, due to their prevalence in both renewable energy devices and high-end electronics. An article in the New Scientist highlighted the importance of a number of REE, many of which most people are be unlikely to have heard mentioned (Crow, 2011). From batteries (lanthanum and cerium) to magnets (dysprosium and neodymium) and lighting (yttrium), the REE are crucial to the advancement of technology and energy saving devices. For example, neodymium is finding most use in the high end magnets that keep the motors turning that power wind turbines and electric cars. In the case of yttrium, the demand outstripped the supply in 2010, emphasising the need to develop deposits containing this and other REE (Crow, 2011). The impact of our dependency on REE has become even more apparent with the reduction in exports by China, which currently controls 97 % of the world’s rare earth production (Pitts, 2011).With the increasing demand for rare earth elements (REE), there is a drive to exploit the known resources around the world. However, the physical beneficiation of the rare earth element bearing minerals is a subject which will require a great deal of investigation to fill the knowledge gaps surrounding these developing rare earth projects. There are numerous articles on REE mineralogy as well as the hydrometallurgical processing of REE concentrates (Alex, Suri, & Gupta, 1998; Peter Gromet & Silver, 1983; Ring et al., 1993; Schnetzler & Philpotts, 1970; Uda, 2000), however a common feature amongst these resources is the lack of detailed descriptions of the physical beneficiation processes required to concentrate REE-bearing minerals. There is work being conducted into reagents and methods for use in recovering some rare earths from their associated ores (Bulatovic, 2010; Ni, Parrent, Cao, & Liu, 2011), but much more in-depth research is required."

Jan 1, 2012

By Pizhi Zhao, Jingwei Zhao, Zhenshan Liu, Yiheng Cao

"A new Al-Mg-Si-Zn alloy designed for automotive outer panel was trial-produced with industrial procedure. The final product shows a strong planar anisotropy. X ray diffraction analysis shows such strong anisotropy is caused by the dominating cube texture component in the final product. The reason for such high cube texture component was investigated by tracing texture evolution starting from the hot roll slab. It is found that certain cube texture components already exists in the hot rolled slab. The density of cube texture component shows as a wavy change through the following1st cold rolling, inter-annealing, 2ndcold rolling and solution treatment. This study shows that the cold rolling in the laboratory can well represent the texture evolution during the industrial production. The results obtained by lab rolling hints that change of second cold rolling reduction has weak effect on the planar anisotropy, when the gauge of hot rolled slab and final sheet are fixed.INTRODUCTIONWith the rapid progress of light-weighting in the automotive industry, aluminum sheets get more and more application as closure panel and structure parts. Recently the dominating alloy for outer panel is 6xxx series, containing the main alloy elements Mg and Si. The popular gradesareAA6016,AA6111, AA6022, and AA6014. These alloys still cannot satisfy the various requirements from automotive manufacturers. Most suppliers of automotive aluminum sheets are developing their own specific grades according to the customer’s demand. To increase the baking response, anew Al-Mg-Si-Zn alloy was designed, concerning the high combination energy between Zn solutes and vacancies formed during the quenching stage of automotive sheet manufacture. This combination is helpful to the precipitation of ß”phase during the paint baking (Wang, 2015,2016; Yan, 2014).The plastic strain ratio (r value)is a key index of the formability of automotive body sheet. A high r value means a good formability. The r values in different directions can be used to evaluate the planar anisotropy of the metal sheets. The trial produced Al-Mg-Si-Zn sheet shows a strong planar anisotropy with respect to r values. Since the r value is tightly related with texture, the texture evolution from hot roll slab (HRS) to final T4P temper was analyzed with X ray diffraction (XRD) to find the reason for the high anisotropy. Besides, the cold rolling reduction (CRR) was varied in the laboratory to modify the texture distribution, i.e., the planar anisotropy."

Jan 1, 2018

By M. Nusheh, C. Bumby, A-H. Puichaud

"Vanadium-bearing titanomagnetite ironsand deposits occur along a 480 km stretch of the west coast of New Zealand. In the present study, the leaching behaviour of NZ ironsand was investigated in hydrochloric acid (2–10 M) solution at 50–80°C for 2 h. The resulting leaching liquors exhibited Fe/V ratios in the range 150–180. The distribution of trace element contaminants between solution and solid residue was investigated, and processing conditions have been determined for rapid and efficient dissolution of Fe, Ti and V into the leaching solution. In addition, mineralogical analysis of raw ironsand and leached residues was performed in order to study the leaching mechanism. Samples were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy (EDX), X-ray fluorescence spectroscopy, qualitative and quantitative X-ray diffraction and inductively coupled plasma mass spectrometry (ICP). Results indicate that the dominant dissolution process follows shrinking particle mechanism. However, ironsand particles containing ex-solution lamellae exhibited a different leaching behaviour compared to homogenous titanomagnetite particles.INTRODUCTION Titanomagnetite ironsand (blacksand) forms Quaternary onshore beach and dune deposits and offshore marine deposits (Figure 1) along 480 km of coastline from Kaipara Harbour south to Wanganui on the west coast of the North Island (Christie, 2016). It attracted the attention of scientists from the earliest times (Galbreath, 1998). The principal minerals in ironsand are titanomagnetite (TTM), ilmenite, quartz and ferromagnesian minerals such as augite, hornblende, diopside, and olivine with smaller amounts of rutile and apatite (Mauk, 2016).Several large ironsand deposits have been discovered and exploited since the late 1960’s. The Waikato North Head and Taharoa mines are currently operating and they have a 2015 measured resource of 400 million tonnes in total and provide over 2 million tonnes of concentrate per year by simple cost effective magnetic separation process (Christie, 2016; Christie & Brathwaite, 1997). The concentrate contains not only 7–8% TiO2 and 56–60% SFe, but also 0.3–0.6% V2O5, is both a valuable titanium mineral and a source of vanadium. All the production is used for steelmaking industries. The other potential for utilizing more of this resource without requirement of integration into an iron and steel producing plant is to develop a hydrometallurgical route with advantages of higher efficiency along with lower emissions. Currently, there is no existing commercial process capable of extracting all three of these elements as industrial-grade commodity products. Acid leaching of TTM concentrate with higher degrees of recovery and selectivity is a key step in any possible hydrometallurgical route."

Jan 1, 2017

By S. Fahland, P. Vogel

"The Gorleben salt dome has been investigated since 1979 for its suitability as a repository for the disposal of high-level radioactive wastes. The geoscientific surface exploration was followed by underground exploration of the site beginning in 1983: underground excavation work included the sinking of two shafts from 1986 to 1994, the excavation of the infrastructure area and of drifts located in the first exploration area EB1 within the following years. The exploration was interrupted for ten years from 2000 to 2010 as part of a moratorium. After the expiry of the moratorium in March 2010, the geoscientific underground exploration at the Gorleben site was resumed. The investigations were interrupted again in autumn 2012 due to a political decision. The exploration programme included extensive geoscientific investigations: geological exploration, geophysical investigations, mining exploration and mining observation, laboratory tests, in-situ geotechnical measurements, geological modelling and numerical model calculations. To analyse and interpret the results of the in-situ measurements and mining observation geomechanical, thermal and thermo-mechanical model calculations were carried out. One of the main elements of the in-situ geotechnical investigations were high-resolution geothermal measurements performed in boreholes used for geological exploration and geotechnical tests.The geothermal measurements are used to evaluate several geotechnical findings, e. g. drift closure, rock deformation, stress change, and are completed by thermal model calculations to analyse and interpret the results of in-situ measurements and mining observation. The model calculations have been carried out using the special purpose JIFE code. To consider the whole exploration mine with the adjoining host rock as well as the successive excavation of drifts and boreholes in detail a three-dimensional finite-element model was developed. The model calculations are used to analyse the cooling-off of the surrounding rock of the drifts caused by ventilation. The cooling-off of the surrounding rock is an ongoing process affecting the results of further geotechnical measurements in the near field of the drifts. To predict a realistic time and space dependent distribution of the temperature field of the host rock within the exploration area which is influenced by ventilation thermal model calculations are necessary. Comparing the calculated temperature field with the in-situ determined rock mass temperature field within the exploration area EB 1 the results show a sufficient agreement. Furthermore there is very good correspondence, both qualitatively and quantitatively, between the experimental and the calculated findings regarding the temperature profiles including the effects of excavation and ventilation of the drifts."

Jan 1, 2015

By C. Tong, B. Hilscher

"Sensor based ore sorting is being rapidly adopted by the mining industry. The ability to boost mill feed grade by rejecting waste grade rocks early in the process has proven revolutionary for some operations.This paper briefly reviews the current position of ore sorting in the industry, as well as abridged results from specific operations such as Barrick, McEwen, New Gold, and two others. The paper also introduces the concept of “Profit Recovery™”, the measuring of recovery based on rock profitability rather than just metal content.IntroductionSensor based ore sorting is being rapidly adopted by the mining industry. The ability to increase mill feed grade by rejecting waste grade rocks early in the processing stage is proving to be revolutionary for some operations. These potential outcomes have been too invaluable to be overlooked by both producing operations and prospective projects, thus leading to a wide range of studies on ore sorting. In addition, the advent of ore sorting has also called for a new standard of recovery analysis. The answer to this is the creation of a new term and concept - Profit Recovery™.This paper evaluates the most recent results of ore sorting in the mining industry, and presents the results from five different mining operations. Additionally, this paper will discuss and evaluate the Profit Recovery™ of each of these operations. The goal of this paper is to address common concerns regarding ore sorting rejects and their actual impact on project economics.State Of The ArtOre Sorting is a sensor-based sorting and pre-concentration technology implemented before the processing stage that is used to reduce the amount of waste reporting to the mill feed. This technology can also be utilized to recover ore from previously uneconomic waste, as well as reduce the mill energy and reagent consumption (Tong, 2012). In greenfield projects, sensor-based sorting can further provide value by reducing processing capital costs. The decline of available high grade orebodies and decreasing head grades has further increased the attractiveness of pre-concentration, and subsequently ore sorting (Lessard et al., 2014).There are currently two notable types of sensor-based sorting: bulk and rock-by-rock. Bulk sorting consists of live, high tonnage sorting that can be installed on a scoop or on a conveyor belt with a diverter. Rock-by-rock is a selective sorting method that scans and sorts individual rocks on a conveyor belt, and rejects rocks using air jets or mechanical levers. Figure 1 shows a diagram for a typical air jet sorter."

Jan 1, 2018

By J. D. Templeton

A petroleum well that is not in use because it has ceased to produce oil/gas economically and dry holes are referred to as abandoned wells. Once a well is abandoned it is plugged with cement and can take anywhere from two days up to a week to cure depending on the number of plugs in the well. Since plugging a well costs capital, most wells are abandoned at the lowest possible cost and with the minimum obligations set by regulation agencies. These wells can present an enduring liability to petroleum companies. However, the depth and abundance of abandoned petroleum wells makes them an economically attractive source of geothermal energy. Geothermal energy harvested from an oil/gas well is a renewable energy source as long as it is extracted in a sustainable manner. The energy can be used to generate electricity, used directly for heating, incorporated into a water desalination process, or used by a heat pump for heating/cooling applications. In this paper we examine the possibility of extracting geothermal energy from abandoned oil/gas wells by studying the heat transfer in underground geothermal heat exchangers installed in these wells. The design configurations for the geothermal heat exchangers embedded inside a petroleum borehole can be a u-tube design or a shell and tube design (i.e. double pipe). Using in-situ gathered information from some representative petroleum boreholes, the effects of key parameters such as geothermal gradient, ground temperature values, and the flow inside of the tubes are evaluated. In order to provide a constant power production the inlet temperature can be adjusted to keep the difference between outlet and inlet temperatures equivalent. Higher differences between inflow and outflow temperatures will result in a less sustainable load put on the in-situ geothermal energy. Adding insulation to certain sections of the designs can minimize the transfer of thermal energy from the fluid to the surroundings. Insulation can also limit the thermal loss between the inflow and outflow tubes in the shell and tube design. Minimizing the energy loss of these designs leads to an increase in the outlet temperature, meaning a higher grade of heat. The sustainability of long term geothermal heat extraction is a balance between the rate at which geothermal energy is extracted and the rate at which the ground formation can replace this heat. Higher outlet temperatures can lead to a larger amount of power generation, and a higher coefficient of performance for heat pump applications.

Aug 1, 2013

By Daniel Hodouin, Mélanie Proulx, Claude Bazin

"Collector and frother are commonly used to induce the floatability of valuable minerals in flotation plants. These reagents are usually distributed down a flotation bank or sometimes added in a single location at the top of the bank. A review of the literature and some experimental results obtained from laboratory and full scale trials indicate that the way flotation reagents are distributed down a flotation bank may influence the flotation response of coarse particles. The paper summarizes these observations which show that the distribution of reagents is a potential tuning variable for process optimization.IntroductionFlotation is in many cases the only way to concentrate sulphide and some oxide minerals. Flotation is a concentration process that uses particle surface composition to induce the selectivity by mean of hydrophobic reagents. The influence of particle size on flotation was firstly analyzed in the 50's1·2 and intensively investigated in the 70's, early 80's and 90's3-18. Most of the observed results show the existence of an optimum flotation size range9 whose recovery is not significantly influenced by a reduction of collector dosage""18. This result brought the idea of using a small portion of the total collector dosage at the top of a rougher bank and to distribute the remaining through the end of the bank to ensure sufficient collection of the coarse particles that need more hydrophobic coverage to attach to air bubbles and be lifted to the surface.This paper discusses the idea of using the distribution of reagents down a flotation bank to tune the operation of the process. Unlike the literature on the effect of reagents (collectors, frother...) dosage that is dense, little attention has been put on the distribution of reagents in a flotation bank. Although research on this subject has not been pushed very far, some operators have recognized the potential of a strategic addition of reagents down a flotation bank19. Except for a few exceptions, the proportions of the reagents to be distributed down a flotation bank are decided according to operator's experience instead of process analysis in relationships with particle size. This paper recalls observations made by different researchers that lead to the idea of using the distribution of reagents as a tuning variable for the flotation process. The paper does not present a detailed analysis or optimization scheme for tuning the distribution of reagents, but analyzes some plant and laboratory results with a view toward the development of a testing methodology and ultimately a validation or rejection of the idea."

Jan 1, 1998

By Isabel F. Barton, J. Brent Hiskey

Chalcopyrite (CuFeS2) is the earth’s most abundant copper ore mineral, but is refractory to leaching with sulfates, chlorides, and other common lixiviants and oxidants. This has led to increasing research into alternative lixiviants for recovering Cu from chalcopyrite. Here, we review the leach kinetics of chalcopyrite in glycine, ionic liquids, and methanesulfonic acid, compared to baseline ferric sulfate and ferric chloride. Glycine (CH2NH2COOH) has long been used in applications such as biocatalysis and electroplating, and has recently been examined as a lixiviant for whole ores and concentrates of both copper and gold. It is nontoxic, biodegradable, and capable of strongly complexing Cu2+. Compatible oxidants are peroxide, dissolved oxygen, and ferric sulfate. Chalcopyrite leaching rate in glycine is chemical reaction-controlled, but the effects of grain size and the reaction orders with respect to lixiviant and oxidant concentrations and mass transfer vary. The use of ionic liquids as a leaching agent for chalcopyrite has been extensively investigated in recent years. This system is based primarily on the use of the imidazolium molecule (C3H5N2), which is a planar 5-member ring structure. This lixiviant has been applied to the leaching of chalcopyrite in the form of pure mineral, concentrates, and ores. Kinetics of ionic liquid leaching of chalcopyrite vary substantially depending on the type and concentration of ionic liquid. Methanesulfonic acid (HCH3SO3) is one of the newest lixiviants available in leaching, having only been examined in the last decade. It has been examined as a substitute for sulfuric acid, since it is less corrosive, is biodegradable, and breaks down to carbon dioxide and sulfate over time. The rate of copper leaching from chalcopyrite by methanesulfonic acid is controlled by diffusion and exhibits a strong dependence on oxidant type and concentration. Despite promising reaction rates and total extraction by some of these novel lixiviants, comparison with baseline ferric sulfate and ferric chloride systems makes it doubtful that any will be commercially viable in the near term. Only at very high reagent concentrations and temperatures, and/or very fine grain size, did any of the systems perform comparably to the much cheaper ferric chloride at extracting Cu from chalcopyrite. Most had similar overall reaction rates and total extraction to ferric sulfate, which is relatively common and cheap. However, the leaching kinetics of these novel lixiviants offer valuable insight into the dissolution behavior of chalcopyrite in various systems.

Jan 1, 2019