Search Documents

By L. Vinnett, T. Ledezma, F. Contreras, F. Díaz

"Mass balances in secondary grinding are subject to critical constraints mainly because of the unknown load distribution from the SAG mills, the uncertainties in the hydrocyclone split estimations and the lack of flowmeters in the key streams. In this paper, a methodology to support mass balances based on the use of radioactive tracer is presented. This approach was successfully implemented in two secondary grinding circuits of Minera Los Pelambres, which operate with ball mills of 21’ x 33.5’. The method allowed the load distribution of the SAG product (secondary grinding feed) to be determined. This load distribution was used as an input in the mass balance data reconciliation.The effective residence times of solid tracers were obtained in the secondary grinding equipment, where irradiated solid was used as a tracer. The residence times were obtained from the parametric deconvolution between the input and output tracer signals. The model fitting was performed to reconstruct the normalized output tracer concentration. Effective residence times of solid tracers in the ball mills ranged from 1.9 min to 9.5 min. The use of radioactive tracer measurement in grinding circuits is a powerful tool to consolidate mass balance results as well as to characterize grinding mills.INTRODUCTIONGrinding is the last stage of the comminution circuits. At this stage, the ore particles are reduced in size by a combination of impact and abrasion, either dry or wet (Austin & Concha, 1994). The grinding equipment mostly used in industrial operations correspond to horizontal tumbling mills (Wills & Napier- Munn, 2006). Tumbling mills employ steel balls or rods as grinding media. Ball mills, which are a type of tumbling mills, use steel grinding media with greater surface area per mass unit than SAG (semiautogenous grinding) mills or rod mills (primary grinding). Hence, the ball mills are suitable to obtain the particle size required in the next separation stages (Napier-Munn et al., 1996; Wills & Napier-Munn, 2006)."

Jan 1, 2016

By G. R. Guillet

Important resources of kaolin, refractory clay and lignite, not found elsewhere in Ontario, occur with quartz sand of glassgrade quality in unconsolidated Mesozoic sediments of the Moose River Basin in northeastern Ontario. These materials comprise the Mattagami Formation of Lower Cretaceous age, which overlie in some places a thin Jurassic unit and a thick Paleozoic section, and underlie as much as JOO m or more of glacial and marine sediments and a uniform capping of muskeg. The Mallagami Formation is known from deep boreholes to exceed 100 m in thickness and to consist of two phases: an earlier Type A unit of dark-coloured carbonaceous clays and lignite, and a later light-coloured (Type B) unit of kaolin-bearing quartz sands and bright-coloured refractory clays. Remoteness, poor access, and difficult physical environment have inhibited the exploration and development of these resources.

Jan 1, 1984

By L. Janku, G. Hancox, M. Villenueve, C. Massey

Wellington lies in a seismically active area 150 km from a subduction zone and in the vicinity of several active faults, which poses a risk to its infrastructure and inhabitants. One of these major faults, the Wellington Fault, runs through the centre of the city and across several lifelines, including the natural gas pipeline and the freshwater pipeline. The first settlement in the area was severely damaged in 1848, soon after its establishment, by an earthquake of approximate magnitude Mw 7.4 - 7.5 (Grapes, Little, & Downes, 1998). In 1855, another earthquake of magnitude Mw 8.2 generated by a nearby fault uplifted the eastern part of the current Wellington area and caused several landslides in the surrounding hills (Grapes & Downes, 1997). The Central Business District lies in the area of a sedimentary basin and partly on reclaimed land. Many residential areas, as well as some vital infrastructure, however, lie on or along the slopes in the surrounding hills. The bedrock in the area comprises predominantly the Torlesse greywacke of Permian – Late Triassic age. The greywacke is tilted to a steep angle, intensively faulted and fractured (Cook, 2001). Even though several studies in the past assessed the seismic risk in the area (e.g. Brabhaharan, Hancox, Perrin, & Dellow, 1994), the studies either focussed solely on the area of the sedimentary basin or based their assessment of the hilly terrain purely on slope morphology (slope angle). Previous studies have shown that slope shape and contrasting materials in the slope can amplify earthquake ground motions, such factors are typically called site effects (e.g. Geli, Bard, & Jullien, 1988). Any attempt to systematically quantify the site effects and consequent seismic response of the slopes and use it to predict the consequences of the next large-magnitude earthquake, has not yet been carried out. In this extended abstract we outline the methodology of a PhD research project, focussed on investigating the site effects on the slopes around Wellington and on creating representative numerical models of ‘characteristic’ Wellington slopes and materials. This extended abstract presents the methodology adopted for the assessment using the Te Ahumairangi Hill site as an example.

Jan 1, 2015

By Andrew Kerr

Overview of Presentation ? Introduction ? An historical context: From 1866 to the 21st century. ? Geological framework for iron ore in the region known as the ?Labrador Trough?. ? Producing iron-ore deposits of the Labrador City ? Wabush area, and near-future production from the Schefferville area. ? Exploration projects representing potential future production?.or expansion of the district. ? Some concluding remarks???

May 1, 2011

By A. G. Pentland

MODELS of mines may be classified under three headings: (a) sheet models, (b) solid models, and (c) skeleton models. Sheet Models are made of sheets of glass, celluloid, or a transparent plastic material. The sheets are mounted in a frame which holds them in a parallel position, either horizontally or vertically. Mine plans are traced on the horizontal sheets; sections on the vertical sheets. The model may be illuminated by electric lights which are separated from the sheets by an opalescent screen. It is viewed from above or from the side in such a way that the plans or sections are superimposed. Sheet models are very useful for the illustration of mines with narrow, steep-dipping veins, but they do not give a satisfactory representation of a large mine with a flat-dipping vein. Large sheets of glass are difficult to handle and to support in a frame.? It is difficult to see through a considerable number of them. Solid Models are made of plaster, concrete, wood, or other material usually in the form of slabs in which the mine workings are indicated by properly dimensioned cavities in the model. The slabs are coloured to show the veins, country rock, faults, etc. The model is divided along selected sections in order to give access to the interior by the temporary removal of parts. Solid models may be used to illustrate large orebodies of the Sullivan type, but they are cumbersome because parts must be removed to study details of structure. Skeleton Models are ones in which the underground cavities are represented by metal, wood, plaster, or wax proportionately shaped and held in place by a frame. They illustrate the work which has been done but do not show the position of the veins, dykes, faults, etc., in the unworked parts. It is necessary to project by eye between workings in order to determine the location of these features. The essential difference between the skeleton model and the solid model is that the skeleton model represents the mine workings by solid forms and does not show the unworked parts of the vein, whereas the solid model shows the vein as a solid and the mine workings as cavities in it. The skeleton model lends itself well to the representation of a large mine with large stopes.

Jan 1, 1944

By J. Zhou1

"The extractive metallurgy of gold ores is largely driven by their grade and mineralogy. The concentration of gold in the crust is extremely low and highly variable, resulting ore variability in many gold and copper-gold deposits. More importantly, gold in an ore may occur in two or three forms (i.e. microscopic gold, submicroscopic gold and surface gold), making gold ore processing extremely challenging. Geometallurgy is a technique to document variability within an orebody and quantify and evaluate the impact of many factors including geology and mineralogy on grinding, flotation, leaching and metal recovery processes. The objective of gold geometallurgy is to reduce and minimize the technical risk in project evaluation, plant design, mine planning and production forecasting through geometallurgical modelling, representative sampling and subsequent systematic mineralogical and metallurgical testwork. Gold deportment study is a powerful tool in characterization of various gold ores. Effective and quantitative gold deportment results are critical and useful for predicting gold recovery and building geometallurgical models of gold ores. This paper provides an overview of geometallurgy fundamentals and applications in gold processing, with a focus being on the ore characterization and gold deportment study.INTRODUCTION Geometallurgy is an inter-disciplinary approach which links the geological, geochemical and mineralogical characteristics to the metallurgical performance of an orebody. Combined with mine planning, it has been used in scoping, prefeasibility and feasibility studies, process design and optimization of gold, copper-gold, copper-moly, nickel and iron projects among others (Williams & Richardson, 2004; Dobby, Bennett, Bulled, & Kosick, 2004; Bulled, 2007; Bulled, Leriche, Blake, Thompson, & Wilkie, 2009; Kormos, Sliwinski, Oliveira, & Hill, 2013; Muinonen, Sciortino, Korczak, & St-Jean, 2013; Leichliter & Larson, 2013; Leichliter, Jahoda, & Montoya, 2013; Hatton & Hatfield, 2013; Baumgartner et al., 2011, 2013; Hoal, Woodhead, & Smith, 2013; Zhou, 2013). The goal of a gold or copper-gold geometallurgical program is to characterize and understand the metallurgical variability of an orebody, such as comminution, gravity, flotation and cyanidation parameters and metal recoveries, and to build a geomet model which can be used to assist in mine planning and to predict the plant performance. In any geometallurgical program, representative sampling is the key to ensure the results of a geometallurgical study will reflect future performance once the plant is commissioned. Geometallurgy compliments, but does not replace, the traditional mineralogical and metallurgical approach during the development and operation of a gold or copper-gold project. Geometallurgy is a methodology for testwork design and a framework for mine planning. The first part of this paper provides an overview of geometallurgy fundamentals and application in gold ore processing."

Jan 1, 2017

By Don Ritz

Smart leaders focus on safety even in tough times. Businesses that retreat into survival mode and ignore safety do so at their peril, risking loss of employee and stakeholder confidence and exposing themselves to financial and reputational loss they can ill afford. It?s a moment of truth when employees and stakeholders learn whether safety is truly your priority or just a convenient cliché for good times. Visionary leaders who build safety culture even in a downturn maintain people?s trust, prevent loss, and position the organization for enhanced success as times improve. Safety is the right business focus in good times and bad.

May 1, 2009

By C. Fortin

ABSTRACT The subject of gold flotation has been reviewed extensively. Most of these reviews focus on the theories of gold flotation and the physical and chemical effects that may impact the efficacy of the gold flotation process. The current status of gold flotation chemistry as it is being applied in industry has not been widely addressed. This paper reviews current gold flotation practice and research advancements and discusses how these applications tie in with the current understanding of gold flotation chemistry. Survey results from worldwide gold flotation operations are analyzed. Potential future areas of gold flotation research are highlighted.

Jan 1, 2013

By Pierre Gy

"Abstract - This paper deals with industrial complexes such as: (1) a mine producing metal-bearing ore and a furnace(s)/converter(s) where the ore is melted into metal, either directly, or after a mineralurgical concentration; and (2) quarries producing the raw materials required for the manufacturing of cement and the kilns to which they are fed.Each mine or quarry operation results from the exploitation of a mineral deposit. This deposit is never homogeneous. The raw materials which are extracted from the mine/quarry can never be safely fed to a "process" such as a cement kiln or a metal smelter, because the devices involved lack the flexibility required to absorb a very inhomogeneous feed. Furnaces and kilns are known to be very sensitive, sometimes dangerously so, with regard to deviations from a certain ideal feed composition.The purpose of this paper is to present the conditions required to optimize the operation of such a complex, so as to maximize the production, the quality of the product, as well as the profit generated. Two key operations are involved: sampling (to know accurately the materials being dealt with) and bed-blending (to achieve the desired degree of homogeneity). The theories of sampling and bedblending have been developed by the author and presented in various books (Gy, 1992, 1998)."

Jan 1, 1998

By Alan Reed

"Afton Mines Ltd. (N.P.L.) operates an 8500-tpd open-pit copper-gold mine near Kamloops, R.C. The pit is currently 480 feet deep and will reach an ultimate depth of 800 feet. The east, south and west walls of the pit are composed of Triassic andesites (Nicola Volcanic Formation) and contemporaneous sub-volcanic intrusions of micro-syenite, microdiorite, diorite and picrite-basalt (Iron Mask Pluton). The north wall of the pit consists of Tertiary sandstones, shales and mudstones (Tranquille formation) and dacitic dykes, sills, flows and tuff s (Kamloops Volcanic Formation).The Afton copper-gold orebody (30 million tons of open-pit ore with a grade of 1.0 per cent copper, 0.016 oz/ton gold and 0.12 oz/ton silver) occurs within the Triassic Iron Mask Pluton adjacent to its faulted contact with Tertiary rocks. The Triassic-Tertiary contact is a complex fault system dipping 65 degrees southward and causing the Triassic rocks to overlie the Tertiary rocks. The detailed trace of this contact is very intricate due to the mutual interference of three principal fault systems.The dominant geological structures in both Triassic and Tertiary rocks are faults striking WNW and dipping 65 degrees southward, i.e. sub-parallel to the orebody (strike faults). Cross faults and oblique faults are abundant and highly significant in some sectors of the pit. The Tertiary sedimentary rocks show an early series of northwesterly plunging folds deformed by a later series of northeasterly striking folds. Major lithological and structural boundaries divide the pit into 8 structural domain s within which the pitwall slope stability is controlled by the local geological structures and lithology.Assay data from production blasthole samples and exploration diamond drillhole samples show a log-normal frequency distribution, with a fairly low relative variance. Variograms computed from production blasthole samples show good continuity with elliptical horizontal zones of influence which are truncated by the major faults that bound the ore zone."

Jan 1, 1983

The extractive industry has the potential to impact the health and well-being of workers, families and surrounding communities. In the current environment of social performance, project planning considers that activities should be conducted in the best environmentally, socially and economically acceptable way across the development cycle (i.e. from exploration ? post-closure). In this context, health impacts of mining can be mapped and extend over the Life of the Community and can encompass worker injury and disease, exposure to communicable and non-communicable diseases, and health outcomes specific to family and community health and well-being outside the fence. To contribute to an emerging field focused on Health and the Extractive Industry, this paper reviews and compares health activities extracted from social and environmental reports published by selected major mining, oil and gas companies with operations in Australia and Canada. The objective of this review is to map corporate approaches to public health management across our previously developed Life-of-Mine within Life-of-Community (LOMLOC) framework in order to identify and compare trends and behaviour in corporate health investments across the project cycle, as well as identify the level of prevention targeted by this investment activity (i.e. primary, secondary and tertiary prevention of detrimental health impact). With the extractive industry facing ongoing rapid growth worldwide, this paper provides preliminary comparative information about corporate health spending by some companies in Australia and Canada. This information serves as a resource for minerals industry managers, civil society and regulators regarding current health management approaches in this sector.

Aug 1, 2013

By P. A. Riveros

This paper describes the leaching of the common copper minerals tennantite (Cu12As4S13), tetrahedrite (Cu12Sb4S13) and enargite (Cu3AsS4) in acidic media using Fe(SO4)1.5, FeC13 or 02 as oxidizing agents. At temperatures <100°C, tennantite dissolves slowly in Fe(SO4)1.5-H2SO4 media, and the rate is directly proportional to the area of the sized tennantite. The rate increases sharply with increasing temperature and the apparent activation energy is 69 kJ/mol. Increasing Fe(SO4)1.5 concentrations slightly increase the tennantite leaching rate. The kinetics of dissolution of disks of synthetic iron-bearing tetrahedrite in Fe(SO4)1.5-H2SO4 media are linear; the leaching rates are slow but increase significantly with increasing temperature, with an apparent activation energy of 120 kJ/mol. The dissolution of sized particles of natural Ag-bearing tetrahedrite in FeC13- HC1 solutions proceeds according to the shrinking core model, and both Cu and Ag dissolve at about the same rate, provided that the total chloride concentration of the solution is sufficiently high to solubilize the AgC1 reaction product. The leaching rates are slow, and the apparent activation energy is 116 kJ/mol. The addition of sulphate ions to the FeC13-HC1 system reduces the tetrahedrite leaching rate to values similar to those realized in the Fe(SO4)1.5-H2SO4 system. At <100°C, enargite dissolves slowly in either Fe(SO4)1.5 or FeC13 media, and the dissolution rate obeys the shrinking core model. The rate increases with increasing temperature and the apparent activation energies are 50-64 kJ/mol. The rate increases slightly with increasing FeC13 concentrations in 0.3 M HC1 media. The leaching of enargite at elevated temperatures and pressures was also investigated. Potentially useful leaching rates are achieved above 170°C, at which temperature sulphate, rather than sulphur, is produced. Lower temperatures (130-160°C) lead to fast initial leaching rates, but the dissolution of the enargite is incomplete because of the coating of the enargite particles by elemental sulphur.

Jan 1, 2007

By Brian Hall

For some years, the mining industry has been consistently delivering returns below the market average. One of the causes is a disconnect between what is perceived to drive value creation by many industry analysts and senior corporate executives, and what actually drives the intrinsic value of mining operations. The perverse effect is that strategies that should increase value are perceived to have the potential to drive share prices down, and vice versa. This paper challenges common perceptions of what drives a mining company?s value. Anecdotal evidence suggests that the key drivers of value in the market, and hence in many boardrooms, are such things as increasing the reserves and production rate, and reducing unit operating cost. However, while the quoted reserves may satisfy ore reserves reporting code requirements to be economic, this does not imply that they are optimal. Often, a proportion of the quoted reserve reduces the potential value of the operation. Metal price increases, increased production rates, and operating cost reductions are all seen as conditions or actions that can improve value, and lead to cutoff grade reductions, thereby increasing ore reserves. However, modern cutoff theory and studies conducted by the author and his colleagues show clearly that, while breakeven cutoff grades will fall in these circumstances, optimum cutoffs may be much less volatile, and may even increase. Results from case studies indicate that value is maximised by right-sizing, not maximising, the production capacities, and by optimising the cutoff strategy. Values of many existing underground mining operations can be increased significantly by a substantial cutoff grade increase. Also, an increase in downside risk, and hence reduced returns, can occur using typical life-of-mine planning strategies if prices received are lower than predicted. Since this is often the case, low industry returns may be a direct result of typical strategic mine planning processes. Relatively simple cost-effective techniques are available to provide senior decision makers with information needed to assess the tradeoffs between their many conflicting corporate goals, and the balance between risk and reward. Often this information is not being generated at all. If it is, decisions affecting the value of the company are occurring by default at relatively low levels within the hierarchy, with senior executives apparently unaware of them or their potential impact. The paper concludes that without a re-evaluation of the way mining projects are valued, to demand proven value optimisation from mining plans by boards and mining analysts, the industry will continue to deliver below average returns.

May 1, 2003

By Z. Ren, M. Tomlinson, E. Asselin

"Organic carbon blinding is a common, yet often partial, solution to the reduction of preg-robbing. A quantitative method to assess the extent of adsorption of a given blinding agent is presented herein. The adsorption of several blinding reagents on various carbon samples is quantified using electrochemical impedance spectroscopy (EIS). EIS results showed that kerosene is more strongly adsorbed on carbon than sodium lauryl sulphate (SLS), while SLS can hinder the charge transfer process of the oxygen reduction reaction on the carbon surface more effectively. The effectiveness of SLS is pronounced when its concentration is higher than 100 ppm. Raman spectra are presented for selected carbon samples: as the area ratio of the disordered peak to the graphitic peak increases, blinding agent adsorption increases.INTRODUCTION The presence of naturally occurring constituents in gold ores may adversely affect the extraction of gold in cyanide leaching since the gold cyanide complex, Au(CN)2–, can be adsorbed by these constituents (M. Adams & Fleming, 1989; Afenya, 1991; Miller, Wan, & Díaz, 2005). Such ores are known as “preg-robbing”. Preg-robbing behavior may arise from natural carbonaceous materials in the ore (M. Adams & Burger, 1998). In the past decades, a number of pre-treating methods have been developed for refractory carbonaceous ores (Arriagada & Osseo-Asare, 1984; Beer, 1994; Dunne et al., 2007; Jiang, Liu, Xiao, & Yang, 2012; Kohr, 1997; Kulpa & Brierley, 1993; Menne, 1992; Menne & Revy, 1994; Moyes & Houllis, 2010; Petrie, Craw, & Ryan, 2005; Simmons, 1996). The method known as blinding is one of the most effective and economical pre-treatment methods (M. D. Adams & Burger, 1998; Albert, 1923; Darrow, 1924; McQuiston & Shoemaker, 1975; Van den Berg, 2000). Blinding, also referred to as blanking or passivation, uses a chemical reagent to passivate the preg-robbing carbon by selective absorption or wetting (Bas, Altinkaya, Yazici, & Deveci, 2012; Brierley & Kulpa Jr, 1993; Dunne et al., 2012; Van den Berg, 2000; Yang, Qian, Song, & Dong, 2013; Yen, Amankwah, & Choi, 2008; Zhou, Jiang, & Choi, 2014). Organic reagents, which selectively adsorb on the surfaces of activated carbon and “smother” the surface, have been used for blinding carbonaceous matter in gold ores prior to cyanidation. Two comprehensive studies by Abotsi and Osseo-Asare and Adams and Burger have been published on this topic (Abotsi & Osseo-Asare, 1986; M. D. Adams & Burger, 1998)."

Jan 1, 2017

By K. K. Dehn

This study focused on determining the stability of thin shotcrete fill fences at a hard rock mine in northwestern Ontario during increased pour rates of paste backfill. Determination of the stability of the fence is needed for both personnel safety and to avoid failure of a fence. Failure of a fill fence during backfill activities would have severe impacts on production and potential hazards to nearby workers. Approved fill fences at the mine are a slender design of 10.5 centimeters of shotcrete applied to a rebar framework with burlap lined ?bedspring? backing. Approved mine standards dictate that fill rates may not exceed 1.5 meters of paste depth per 10-hour shift when pouring behind a flat fill fence. To decrease the backfill cycle time the study looked at fence stability during increased pour rates of 2.5 meters paste depth poured within a 10-hour shift. An instrumentation design was developed including pressure cells, strain gauges, and tilt-meters that were built into experimental fences to observe the effects of increased pour rates on lateral wall pressures, strain development in the rebar and shotcrete reinforcement, and physical deformation patterns along the face of the fence. The data was analyzed for overall stability.

May 1, 2007

By E. P. Evoy, A. W. Jolliffe

"The Uranium deposit of Gunnar Mines, Limited, is on the south shore of Crackingstone peninsula in the Beaverlodge area of northern Saskatchewan.The ore consists of disseminated pitchblende and uranophane in brecciated syenite, and forms a tubular or pipelike body, outcropping at the surface and plunging southward at about 45 degrees for a known length of1,400 feet (see Figure I). The upper portion is being removed by open-pit mining to a depth of 300 feet below adjacent Lake Athabasca. The remainder will require underground mining methods (see Figure 2).The property was staked in July, I 952, and the orebody was subsequently defined by about 70,000 feet of diamond drilling. A 1,250-ton mill was completed in 1955, and production commenced in September of that year with ore from the open-pit operation. The mill is presently being increased to 1,650 tons capacity, and a three-compartment vertical shaft is being sunk to 1,250 feet in preparation for underground mining.GeologyThe mine property is underlain by an assemblage of Precambrian metasediments known locally as paragneiss, granite-gneiss, and syenite. These lie on the southeast limb of a southwest-plunging anticline, strike about north 75 degrees east, and dip southward at about 45 degrees. Para- gneiss outcrops in the northwestern half of the claim group, and again on the islands south of St. Mary's Channel. The granite-gneiss lies conform-ably within the paragneiss and makes up the southeastern part of the property. The syenite forms an irregular, triangular-shaped mass within, and near the footwall of, the granite-gneiss band. Small lenticular bodies of mafic rocks are also present, the former being most prevalent in the paragneiss.The granite-gneiss is coarse to medium-grained, pink to grey, well foliated, and composed of feldspar (65 per cent), quartz (20 per cent), chlorite, and minor mica. The general concordance of its contacts with paragneiss and the absence of intrusive relationships along these, the presence of uniformly oriented inclusions of obviously sedimentary origin within the granite-gneiss, and the variation in colour and texture across the strike all strongly suggest that this member represents a granitized sedimentary rock."

Jan 1, 1949

By F. W. Gray

Foreword: It is not my purpose, in this address, to write the history of the Geological Survey of Canada, which has from time to time been reviewed by the officers of the Survey itself, and by men more competent than myself to handle so large a subject, but rather to set out some of the reasons for the regard in which the Survey is held by our Institute, the body best qualified to speak for the mining men of Canada. And, a further purpose is to publish the desire of our Institute that the work of the Survey shall be maintained at the highest pitch of efficiency the resources of our country. will permit, because to scrimp expenses on the Survey is &apos;to save at the spigot and lose at the bunghole." A historical examination of the grounds on which it may be asserted the Geological Survey has been, and still is, of fundamental economic value to our country, discloses a prescience on the part of the forefathers of Canada, calling for our admiring gratitude, and reveals a unanimity among the real leaders of Canadian thought, on the value of geological knowledge, that is impressive in its continuance dawn to this date. There seems always to have been before our people the realisation that large stretches of Canada are unfitted for agricultural settlement, and that our glaciated areas, the barrens and tundra of the North, and our extensive mountain ranges, had promise of compensating mineral content which the geologist and the prospector, labouring together through the years, would disclose. The Geological Survey is one of Canada&apos;s oldest public services, distinguished by an unimpaired tradition of honourable and useful labour. Founded in 1843, under William Edmond Logan, not yet &apos;Sir William&apos;, one year after the Act of Union, it was directed by him until 1869, or into the early years of Confederation, so that the early years .of the Survey were also, politically, the formative years of Canada, as we know her today.

Jan 1, 1932

By M. Samuels

"Block and panel cave mining methods are being increasingly proposed as they allow massive, deeply situated ore-bodies to be mined economically at a time when discovery rates of significant near surface deposits are declining. Cave-to-Mill, a mine-to-mill approach for block cave mines, defines ore block models with respect to both mine and mill performance. A cave-to-mill study for the New Afton block caving operation focused on identifying value opportunities related to fragmentation and sorting for a future lift as development progresses deeper. The lack of selectivity and potential for dilution associated with the block cave mining method results in many caving operations having to mine and either dispose of or process material that is below cut-off grade at certain stages of production. As an outcome of the study, the variation in cave fragmentation size and the sensitivity of mill throughput to feed size was examined. To evaluate the amenability of bulk and particle sorting, Prompt Gamma Neutron Activation Analysis and X-Ray Fluorescence sensors were tested. A conceptual bulk and particle sorting flowsheet is presented. Grade data from regular underground sampling was used to predict the performance of a bulk sorter. A heterogeneity analysis of material reporting to drawpoints helped to identify areas of the extraction level that experience high variations in grade and thereby stand to benefit from dedicated ore and waste material handling systems should underground bulk sorting be implemented.INTRODUCTION Block and panel caving are low-cost underground mass mining methods that are suitable for excavating weak, massive and steeply-dipping orebodies. Accordingly, cave mining methods have predominantly been used to mine copper porphyry and diamond bearing deposits. Due to the increasing depletion of near-surface orebodies, it is expected that block and panel caving methods will be increasingly used in the copper-gold industry. Their implementation holds significant potential to extend the life of existing open-pit operations by providing an economic means to access ore located at depths that are beyond the practical limits of open-pit mining. Examples of cave mines proposed for British Columbia include the Kwanika Mine, Red Chris underground, Kemess Underground project, and the Iron Cap and Mitchell cave mines of the Kerr-Sulphurets and Mitchell (KSM) project (Moose Mountain Technical Services, 2017; Imperial Metals, 2017; Golder Associates, 2017; Tetra Tech, 2016)."

Jan 1, 2018

By J. G. Whellock, J. W. Matousek

"In spite of their importance to the economics of many metallurgical projects, the values and technical aspects of precious metals losses in smelting operations are relatively undeveloped subjects. This paper attempts to provide a condensed overview of precious metals losses in pyrometallurgy, using some of the limited production and experimental data available. It is intended for three general groups of metallurgists - operators attempting to improve recoveries, cost-accounting engineers making estimates of metal losses in new or modified smelting plants, and research engineers and students.Distribution coefficients of precious metals, the ratios of metal or matte assays to slag assays, are convenient means of comparing smelting processes and the tendencies of the different metals to enter the slag. For silver in lead blast furnaces this ratio is approximately 250;for gold and the platinum group metals in submerged-arc, electric furnaces it is 900. The ratio for gold and PGMs in converters varies with the degree of oxidation of the charge. The over-all cycle-average for industrial installations is tentatively estimated to be 35.IntroductionThe magnitude of precious metal s losses in pyrometallurgical operation s is difficult to assess. The primary producers are generally reluctant to discuss the subject. The by-product producers (the large sulphide smelters o f copper , nickel, and lead) might be more willing to disclose information, but these have precious metals in their feeds in such dilute quantities that accurate accounting is extremely difficult. It is not until numerous processing steps have been taken t hat the precious metals become sufficiently concentrated to permit acceptably accurate sampling and analytical procedures to be followed. Thus, knowledge of the precious metals contents o f the intermediate mattes and slags may simply be unavailable."

Jan 1, 1990

By Rowena Anderson

Mining companies are now looking for more effective ways to engage the community in public participation. Consensus-based approaches are becoming the most popularly applied way of achieving meaningful public participation. This paper introduces the principles surrounding consensus-building approaches and the processes for getting them started. The Healthy Communities Movement is one such consensus-based approach that offers a well-established holistic model for conceptualizing a healthy sustainable community. It also highlights the importance of public participation as an essential component of achieving a sustainable community. The paper concludes by illustrating how current company-community relations programs can utilize these models.

May 1, 2002