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By William D. Gallant, Thomas M. Barczak, Carol Tasillo

"This paper describes the results of full-scale testing of several multi-layered wood crib configurations that were tested in the Bureau of Mines mine roof simulator in cooperation with the Cape Breton Coal Research Laboratory and Cape Breton Development Corporation of Sydney, Nova Scotia. Nine different crib configurations currently being used as wood packwall supports for advancing longwall applications in Canada were evaluated. Configuration parameters understudy included the aspect ratio (height-to-width relationship) and percentage of solid material used in the crib construction. Test results and generalized wood crib behaviour are discussed in detail. Recommendations are made concerning crib constructions to maximize strength and stability. A cost benefit analysis of multi-layered wood crib configurations is made. A comparison of laboratory results and underground observations of several wood packwall supports in the Sydney coalfield suggest in situ load capacity is less than that measured in laboratory testing. Reasons for the apparent decrease of in situ load bearing capability are described.IntroductionA cooperative effort was undertaken by the U.S. Bureau of Mines with the Cape Breton Development Corporation (CBDC) and the Cape Breton Coal Research Laboratory (CBCRL) to evaluate the behaviour of gateside packing materials used in advancing longwall mining applications in the Sydney coalfield. As part of this effort, full-scale tests were conducted on wood packwall supports in the Bureau's 3-million pound (13.3 MN) active load frame.Nine different pack configurations were evaluated as part of this study. The wood packwall supports were multi-layered crib constructions from 6 in. (0.15 m) by 6 in. (0.15 m) cross section timbers using timber s 30 in. (0.75 m) and 60 in. (1.5 m) in length . The percentage of solid material in the crib constructions varied as illustrated in Figures 1 and 2. A summary of crib constructions is provided in Table 1."

Jan 1, 1991

By H. Craig Boyle, Craig H. B. Leitch

"The Trout Lake stockwork molybdenum deposit is located in the Selkirk Mountains of British Columbia, 50 km southeast of Revelstoke. The property is being explored by a joint venture between Newmont Exploration of Canada and Esso Minerals Canada.The deposit is associated with a small granodiorite stock of Upper Cretaceous age (76 Ma) which has variably altered the surrounding schists, argillites and marbles of the lower Paleozoic Lardeau Group to hornjelsic biotite schists and skarn. The intrusive is composed of a small stock and an intersecting network of northeast- and northwest-trending dykes at surface that coalesce downward into a larger stock. There are two main phases of intrusion, with an earlier quartz porphyritic granodiorite cut by an intra-mineral ""quartz diorite"" porphyry. A strong sub-vertical north-trending fault controls the distribution of the mineralized stock work and displays post-mineral movement.Molybdenite, accompanied by pyrite and pyrrhotite, is mainly present along the margins of veins in a well-developed quartz stock work, but occasionally is strongly disseminated in microfractured intrusives. The stock work is strongest in and around the contacts of the intrusive and its apophyses, and occurs over a vertical range of more than 1,000 m. As defined by the 0.10% MoS] contour, the main mineralized zone is up to 300 m long by 200m wide. Preliminary drill-indicated reserves, currently being revised, are approximately 50 million tonnes of 0.23% MoS2, within which are several zones of higher-grade material. Hydrothermal alteration, as defined by quantitative X-ray diffraction studies on composite core sections, is composed of a central quartz/K-feldspar/albite/minor biotite zone coincident with molybdenum mineralization, which is overlapped by a slightly later, antipathetic quartz/ sericite/pyrite zone. Ankeritic carbonate is also a common alteration mineral, but only traces of fluorite, and no topaz or sulfosalts, have been observed. Analysis for trace elements such as Sn, W, Bi, Sb, As, Hg, U, Ag, Au, Mn, Cu, Pb, Zn and F has been limited except for Sn and W, which appear to be zoned inside and outside the Mo zone respectively; the other elements do not show detectable patterns thus far."

Jan 1, 1983

By V. Casaletto, L. Widdifield

"Equipment capable of higher production requires more sophisticated maintenance programs. Reduction in fleet size through use of modern technology requires higher utilization and greater availability.Caterpillar's maintenance control system program will display the capabilities of computer technology in a maintenance environment. Utilizing such resources will provide increased availability, lower inventory requirements, fewer last minute disasters, and lower cost per ton for maintenance. High production from premium quality equipment can only be realized by good planning and care, executed by maintenance and operating personnel acting cooperatively.IntroductionAccurate information is the key to accurate decision making. In today' s competitive industry, mines' teeter on the brink between profit and loss. Their survival will be predicated on their ability to retrieve, analyze, and formulate accurate information regarding the operating costs of mobile equipment. This paper deals with the impact of managing equipment operating costs and introduces a computerized control system designed for monitoring and controlling these costs.Caterpillar has produced several computerized modelling programs designed at taking the guesswork out of equipment selection and management. The most basic of these is Equipment Investment Analysis (E.LA.). This model compares two or more alternatives over the projected life of the machine. It deals with comparisons in the owning and operating costs of equipment, as well as, their productivity over a specified period of time.In order for a computer model to be credible as a decision making tool, it must be simple to use and the results measurable and accountable . Caterpillar has introduced several computer models to assist the industry in selecting and managing an equipment fleet. These programs allow the user to predict and monitor the operating costs and production capability of mobile equipment. They are often used in the machine selection process to select equipment which best suits a mine's long-term cost per tonne objectives. After the optimum selection is made, Caterpillar's Maintenance Control System provides an efficient management tool to monitor and verify the data used in the selection model."

Jan 1, 1992

By G. E. Rowan

"DURING the dark ages, the cherished dream of chemists was to find a process for converting base metal into gold. Many a wealthy-but-gullible patron lost a fortune in the search. Men who work with metals today are a bit more realistic. I haven't heard of a metallurgist who expects to develop any one alloy that will resist all corrosive media. In the field of stain-less steels, there are about forty different types of alloys that are used where corrosion is a •problem.A stainless product is ordinarily selected because it offers one or more of the following qualities:(1) Resistance to corrosion (2) Resistance to oxidation at high temperatures (3) Good mechanical properties at room temperature (4) Good mechanical properties at high or low temperature (5) Attractive appearance (6) Ease of maintenanceToday we are interested in discussing the stainless steel family of alloys because of their .ability to resist corrosion. We• will not try to explain the Theory of Corrosion. Let us assume that, when surface potential and oxide formations are properly controlled, iron will resist attack in various chemi.cal solutions. The addition of alloying elements to iron does this for stainless steels. The principal stainless alloys used by various Canadian industries are listed in the accompanying Table."

Jan 1, 1959

By Leon C. Botham

?? Review of Requirements ?? Components of Modeling ?? Water Management ?? Tailings Management ?? Primarily a water management problem ?? Solids relatively easily contained ?? Process flows and runoff a continuous stream over life of mine ?? Need to allow this to safely happen over wide range of conditions

May 1, 2008

By I. C. Brown

Introduction Many tables of nomenclature for igneous rocks have been introduced from time to time, and each has its strong proponents. As a result, any discussion of igneous? rocks is apt to prove confusing unless the names used for these rocks are defined. This ?became so obvious to a discussion group, formed by the members of the Geological Survey of Canada in 1948, that an attempt was made to establish a scheme of nomenclature that could be used by any member mapping anywhere in Canada. The writer was asked to co-ordinate the ideas presented by individuals in the discussion group, to arrange them in tabular form, and, later, to distribute copies of the resultant table to Canadian universities, provincial geological surveys, and some other geological discussion groups. Many useful suggestions and criticisms were received, were studied ?by members? of the original group, and, so far as practicable, were incorporated in the scheme of nomenclature. The result is the table presented here. This nomenclature of igneous rocks is at present being used by most members of the Geological Survey of Canada who are working with igneous rocks, and by some Canadian universities. We hope it will be found useful and be more widely accepted. With this idea in mind, certain principles were adopted in drawing up the nomenclature.

Jan 1, 1952

By David Nicholls

?Overview of New Afton ?Reserves and Resources ?Geology and Mineralization ?Exploration ?Capital Project Development to Date ?Mine Development ?Processing ?Construction ?LOM ?Health, Safety, Environment and Social Responsibility Overview of New Afton ?Fully owned by New Gold Inc ?Large gold-copper porphyry deposit, amenable to block cave mining, production commencing in 2012 -1 million ounce gold reserve -1 billion pound copper reserve -Estimated 13 year mine life ?Low operating cost ?Estimated capital expenditure requirements -Spend to date ?US$200million -Remaining to be spent ?US$400milllion ?Robust economics ?Excellent location and infrastructure ?Significant cash flow contributor for the Company

May 1, 2010

By S. Masambi, S. M. Bradshaw, C. Dorfling

The presence of iron in base metal leach solutions complicates nickel and copper recovery processes. Leach solutions are commonly purified by precipitating iron as hematite, jarosite or goethite. Fast oxidation of ferrous to ferric is an important step to remove iron by precipitation at low pH values. This study reviews the ferrous oxidation mechanism and reaction rates in chloride media using molecular oxygen. This work contributes to the development of a better understanding of iron precipitation processing steps, which continues to be an important matter in hydrometallurgy. The specific objectives were to investigate (1) the effect of key process variables (acid concentration, copper concentration, and temperature) on the rate and extent of ferrous oxidation by dissolved oxygen and (2) the oxidation mechanism by varying chloride and hydrogen ion concentrations separately. Batch oxidation tests were performed using synthetic chloride solutions containing 45 g/L Fe and 3 g/L Ni at 50 and 80°C, dissolved Cu concentrations (0.3 to 3 g/L) and HCl concentrations (2 to 4.6 M). Regression analysis indicated that the significance of the effect of different variables on the extent of oxidation achieved after five hours decreased in the following order: HCl concentration > Cu concentration > temperature. Increasing the HCl concentration from 4 M to 4.6 M caused the degree of oxidation achieved after two hours to increase from 58.3% to 98.1%. The catalytic effect of dissolved copper on ferrous oxidation was more significant at low acid concentrations. Experimental data suggest that rapid oxidation of ferrous is possible at high HCl concentrations for two main reasons. First, the formation of ferrous chloride complexes allows ferrous oxidation to proceed without the formation of superoxide as an intermediate product (the rate limiting step in dilute acid solutions). Second, the formation of ferric chloride complexes stabilises the oxidation product.

Jan 1, 2016

By S. Makni, S. Koppalkar, A. Bouajila

This paper reviews briefly the gravity recovery involving conventional gravity separators and centrifugal gravity separators. The advantages of semi-continuous gravity separators will be discussed. Techniques for upgrading the gravity concentrates will be addressed briefly. The research efforts in optimizing semi-continuous gravity separators will be recalled. Innovative gravity circuit for eliminating or minimizing the use of complex processing schemes will be reviewed. On-going gold gravity research at COREM has revealed that gold particle shape transformation is the main factor explaining the lower recoveries of the plant units. Efforts to devise possible remedies for improving gravity recovery at plant will be discussed.

Jan 1, 2011

By Jason Mewis

Jason Mewis is the founder and president of ENGCOMP, a consulting engineering firm in Saskatoon Saskatchewan focusing on the mining sector. He has over 17 years of experience working on projects for the heavy industrial market in Saskatchewan, as both a Senior Structural Engineer and Project Manager. Jason is an entrepreneur with experience in many areas including estimating, planning, facilitation, and Risk Analysis. He has presented at many seminars and conferences across North America on the subject of Project Risk and and has become recognized for his expertise in this area of project management.

May 1, 2013

By D. A. Nelson, Wedding. R. E.

"A planned production increase of 1.25 million tonnes per year at Domtar's salt mine in Goderich, Ontario required an increase in the underground mine ventilation system from 320,000 to 700,000 scfm, The design of the expanded facility included the addition of a 22-foot-diameter shaft to augment the existing production and service shafts.A preliminary review of the ventilation requirement s indicated that in order to pr ovide good economic design for the expanded system, a comprehensive ventilation survey of the existing system was required. The survey was completed in the latter part of 1980, and subsequent engineering design and equipment selection proceeded throughout 1981.This paper presents the methods used to carry out the survey. Particular attention is given to the numerous challenges presented in determining air flows in the large 45-ftwide by 43-ft-high airways. Emphasis is placed on practical field survey techniques.A mathematical model of the ventilation system using a computer program is described, and the application of this program to provide design data and assist in equipment selection is discussed. Economic sizing of airways and fan selection are analyzed considering horsepower and operating costs.IntroductionThe Goderich Mine of Sifto Salt Division, Domtar Inc., is located on the eastern shore of Lake Huron in the town of Goderich, Ontario, and has been operating since November 1959. The salt is extracted by a modified room-and-pillar method, and the workings advance at a rate of 1.5 miles per year by undercutting, drilling and blasting. The surface mine area consists of a 12-acre site in the Goderich harbour, at the mouth of the Maitland River, and the underground property consists of approximately 2,700 acres lying mainly under Lake Huron."

Jan 1, 1983

By D. H. Ryan, B. Abdul, M. Pernechele, E. Asselin

Hydrometallurgical processing of sulphide concentrates at medium temperature (150°C) produces residues, which contain valuable metals (Cu, Ni) as well as sulphur and iron bearing minerals and phases. The low solubility of iron during the medium temperature processing of sulphide ores can favour the formation of poorly crystalline, nano-scale iron oxide/oxyhydroxide phases. A better understanding of the formation and structure of these iron precipitates may elucidate key factors that would ultimately result in lower valuable metal losses and more stable leach residues. Residues from two medium temperature leach processes were characterized by Mössbauer Spectroscopy. Some portions of the Mössbauer Spectrum were suspected to be linked to jarosite but could not be positively identified as such. There was a broad range of disorder and substitution present in the material and solely attributing it to jarosite proved difficult. Various synthetic jarosites with Cu substitution were precipitated for Mössbauer analysis. These were then characterized by Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM), Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) and Mössbauer Spectroscopy. The Mössbauer Spectra of the synthetic jarosites is compared with that of the residues from medium temperature (150°C) sulphide concentrate leaching.

Jan 1, 2014

By W. A. Jankola, M. T. Martin

"The world's first zinc pressure leaching plant at Cominco's Trail operations started production in 1981. Sullivan zinc concentrate is leached at the rate of 190 tpd in a four-compartment autoclave at elevated temperatures and oxygen pressures to produce a zinc sulphate solution and elemental sulphur. Zinc extraction exceeds 98% and sulphide to elemental sulphur conversion exceeds 95%.The sulphur is recovered from the discharged slurry in the underflow of a hydrocyclone, and is upgraded as a flotation concentrate. The concentrate is dewatered, melted and filtered to produce a polished sulphur product of better than 99% purity. An alternative sulphur recovery process employs an unique sulphur separation method that recovers over 90% of the sulphur in the molten state. The remaining sulphur is recovered by flotation following flash discharge of the slurry. The product slurry containing the zinc sulphate solution and the iron-lead residue joins the existing roast-leach zinc plant for purification and zinc electrowinning.IntroductionIn 1981, Cominco Ltd. commissioned the world's first commercial zinc pressure leaching plant at their Trail operations in British Columbia. As part of a $700 million modernization and expansion program for lead and zinc started in 1977, the company installed the first o f two autoclave trains.Prior to pressure leaching, zinc production was closely tied to acid and fertilizer production. Sulphur dioxide produced from roasting the concentrates had to be converted to sulphuric acid. Thus, any expansion of zinc operations with the roast-leach technology would have required extensive modifications to the acid and fertilizer plants as well as to the roasters. Zinc pressure leaching, on the other hand, offered a one-step dissolution of zinc from the concentrates with high extraction, and production of elemental sulphur. The associated dust and sulphur dioxide generated in the roasting process are both eliminated from the working environment of the pressure leach facility. The flexibility allowed by producing elemental sulphur, and the opportunity to break the sulphuric acid link for about 25 per cent of the targeted 272,000 tonnes per year zinc production was very appealing. The process was successfully demonstrated at a pilot plant in 1977(1-6)."

Jan 1, 1985

By J. M. Bowen, P. Wemyss

"Gold losses to natural carbonaceous matter during cyanide leaching have been investigated for over a century. The variation in the severity of the problem from one ore to another has led to a range of different processes being implemented at different mine sites. Most commercial options utilise one or more of the following processes: roasting, carbon pre-flotation, organic blinding, CIL, chlorine passivation, pressure oxidation, biological passivation, elevated temperature CIL, RIL and thiosulfate. This paper provides a background to identify the most appropriate process or combination of processes for a particular ore. It also presents information on how these processes may be implemented, drawing on information in the literature and from current or recent applications at operations such as the following: Stawell, Kumtor, Penjom, Twin Creeks, Macraes Flat, Kittilä, Fosterville, Inata, Carlin, Goldstrike, and Jerritt Canyon. Various process options have been dismissed, or deemed unsuccessful due to limited knowledge available on the strengths and weaknesses of the different options and their implementation. The authors have collectively been involved in flowsheet development and project implementation in four commercial plants that have treated preg-robbing ores.INTRODUCTION Cyanide processing has been the mainstay of gold recovery for well over a century. It is generally a very effective process with over 90% recovery on free milling ores, but complex and refractory ores may only give 0–50% recovery with conventional processing (La Brooy et al., 1994). People have written about gold losses to natural carbonaceous matter during cyanidation for over a century e.g. Feldtmann, (1915). The earliest reports related to African operations, but the issue has since been reported in Canada, North and South America, Australia, Russia and China. The phenomenon is usually referred to as ‘preg-robbing’ dating from the times before the use of granular activated carbon for gold recovery, when gold was lost from the pregnant solution before it could be separated from the leach solids and recovered by cementation. Many excellent reviews have been published e.g. Dunn et al. (2013), summarising the options considered and where they have been applied commercially."

Jan 1, 2017

By Marc C. Betournay, John E. Udd

"In this study, the authors investigated the stabilities of slopes cut predominantly into Trenton limestone in a large quarry in the Montreal region. Analyses of the bench and pit walls indicated that small-scale toppling, ravelling, and wedge failures are the most likely modes of instabilities. Because most of the joints dip steeply, however, the conclusion was made that relatively high walls could probably be justified.The field investigations were supplemented with the determinations of the shearing strengths of artificial discontinuities that were cut into samples of the limestone. The properties of a fine-grained limestone were found to be influenced very much by the magnitudes of the loads that were applied, while the properties of a crystalline limestone were found to be much less, or not load-dependent.The study is one of a number that are being conducted in this area.IntroductionExtensive quarrying has been done in the sedimentary strata of the Montreal area for a very long time. By any standards, it can be said that the Island of Montreal is a major mining area. At present, approximately 20 quarries are being operated in, or near, the city of Montreal.In addition to the millions of tons of limestone that are removed each year, a large number of excavations for foundations are cut into the sedimentary rocks.To date, however, very little information has been published concerning the engineering properties of the local geological materials. No mention is made of this aspect in the references which are presently available.Because of this lack of information, the senior author has initiated a study in which the strength properties of most of the rock types, and of the natural discontinuities contained in these, would be investigated. To date, the results of one other investigation have been published and other work is in process. It is hoped that the end result will be a comprehensive knowledge of the important strength properties of all of the rocks in the entire region."

Jan 1, 1983

By B. M. Das, V. J. Hucka, J. H. Tu

Subsidence can cause serious damage to surface installations such as railroads, highways, pipelines, buildings and other facilities over a period of many years. Although total elimination of the effects of subsidence is difficult, the damage can be minimized through a systematic analysis. An example of such a study for reducing the effects of subsidence on pipelines is presented in this paper. Subsidence-induced stresses on a pipeline over some coal mining properties in Utah have been analyzed using a computer with graphics capabilities. The results are useful in predicting the extent of damages due to mining subsidence. In view of the gradual replacement of room-and-pillar mining by longwall with caving, this sort of analysis will become more and more important. In the next phase of this study the predicted results will be compared with the permissible stress levels on pipelines over actual subsided areas in an actual case.

Jan 1, 1989

By F. E. Patton

"IntroductionAT NORANDA, the strength of the ore and wall-rocks per-mitted mining in large open stopes. While some of the orebodies were small and could be mined out in one stope, in most cases their size was such that it was essential that ore pillars be left during the first stage of mining. In these cases, backfilling has been necessary for ground control and to facilitate the later recovery of the ore in these pillars.This paper discusses the development of the •backfill and •its use in pillar recovery.GeologyThe ore bodies at Noranda occur as replacement deposits in a block of rhyolite flows and breccias, bounded on the north by the Horne Creek fault and on the south by the Noranda Andesite fault. Mineralization consists of pyrite, pyrrhotite, magnetite, chalcopyrite, sphalerite, gold, and various tellurides.The main orebody is a massive sulphide deposit designated the 'H' orebody. It is elliptical in plan, measuring roughly 400 feet by 800 feet, and is divided into two zones -Upper H, extending from surface to the 1,500-foot level, and Lower H, from the 1 ,500-foot level to just below the 3,000-foot level.Mining MethodsOpen stope mining in both Upper H and Lower H zones has been fully described in previous publications (1). A brief review only of the mining methods will be given here."

Jan 1, 1952

As part of the Australian Mineral Industries Research Association (AMIRA) P9 project, methods of characterising both the ore and the machines in flotation circuits have matured considerably over the past 15 years. Machine characteristics include gas dispersion measurements, such as bubble size, gas hold-up and superficial gas velocity. Ores can be characterised in terms of floatability parameters on a size and mineral basis. Measurements have been performed on various copper plants in many countries around the world over the last 5 years. This paper outlines the cell and ore floatability characteristics of each copper plant and provides a discussion on the differences between these plants. In general, most porphyry copper ore bodies are processed at high tonnage through several parallel banks of cells at each stage of flotation. The floatability parameters of these copper ores are very similar in terms of rate of flotation and proportion of fast, slow and non-floating material. The cell characteristics are also similar, with superficial gas velocity, bubble sizes, and gas hold-up values being of similar magnitude. Investigation of the similarities and differences of the modem copper flotation circuits has allowed an increase in understanding of the particularities of copper flotation. Comparison against other copper circuits provides a benchmark and opportunities for future optimisation.

Jan 1, 2007

By T. S. Li, D. Ilievski, I. Livk

Micromixing of the fluid and the particulate phases in a continuous gibbsite precipitator was investigated for three different micromixing states, namely maximum mixedness (MM), complete segregation (CS), and maximum mixedness of the fluid but complete segregation of the particulates (MMF-CSP). The influence of the micromixing on continuous precipitation of gibbsite was studied at different precipitation conditions via simulation. Three different cases were considered with respect to the precipitation kinetics: (1) gibbsite secondary nucleation is favoured with slow crystal growth and agglomeration rates; (2) gibbsite crystal agglomeration and growth are dominant mechanisms with secondary nucleation suppressed; and (3) gibbsite crystal growth is the only relevant phenomenon. Simulation results for the cases (1) and (3) showed that the crystalline products for both the MM and MMF-CSP micromixing states were very similar, but the product obtained from the CS micromixing state was considerably different. This indicates that at those precipitation conditions the fluid micomixing has the dominant effect on the product properties, and the particulates micromixing effect is insignificant. However, when operated under the conditions of fast crystal growth and agglomeration kinetics, i.e. case (2), both the fluid and the particulates micromixing were found to affect the precipitation process, resulting in a significantly different product. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists ofCIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

By D. F. Sherwin

"THE AREA which is described in this paper (Fig. 1) includes the continental margin of eastern Canada extending from the Gulf of Maine to the north edge of the Grand Banks, which, including the continental shelf, slope and rise, comprises an area of about 600,000 square miles. The paper is intended to give a background of the geological setting of this region in the context of its ultimate potential for oil and gas reserves in close proximity to the Nova Scotia energy market.HISTORY OF EXPLORATIONThe history of geological exploration of this area really began in 1878, when U.S. fishing boats brought back samples of rock recovered in trawls from their expeditions to the long-famous fishing banks off Canada's East Coast. Tertiary and Cretaceous fossils recovered from these samples indicated that the eastern Canadian continental shelf was actually the submerged northern extension of the Atlantic Coastal Plain."

Jan 1, 1972