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By Edward Sampson

Bases of National Power At a time when the economy of the world is in a particularly troubled state it is appropriate to examine some problems of the distribution of natural resources. I should like particularly to call attention to the remarkable increasing demand for natural resources, to give an analysis of the demand for certain mineral resources, and to direct attention to some problems in satisfying this demand. All industrial power is based on natural resources and the most basic of these are soils, energy resources, and mineral resources. There is a strong interrelation of these resources, more than is obvious, and I shall take up certain aspects from the point of view of a geologist. Few nations are well endowed with all three of the kinds of natural resources I have mentioned and much has been done by some small countries whose peoples are industrious and enterprising and where conditions for free world trade have been favourable. However, major industrial power is dependent on a substantial endowment of all three classes.

Jan 1, 1949

By C. Hudson, D. Tremblay, A. Frey

"A discussion of the design, challenges and successes associated with the commissioning of the gravity recovery circuit at Canada’s newest open pit gold mine - Atlantic Gold’s Moose River Consolidated Project in Nova Scotia, Canada is presented. An overview of the project, its historical significance and overall flowsheet is provided with special focus given to the design and selection of the gravity circuit equipment including the scalping screen, gravity concentrators and the novel intensive leaching technology selected for the project. The performance of the gravity circuit is benchmarked against the feasibility study process design specifications and the outcomes are discussed. Challenges encountered during commissioning are also presented, including the use of third-party automation and the effects of screen sizing on overall gravity circuit performance. Mechanical modifications made to the Sepro Leach Reactor for the Moose River project are also discussed. A detailed technical review of the mechanical and operational aspects of the Sepro Leach Reactor is provided with key operational data on leach times, recoveries, reagent usage, solid-liquid separation, pregnant solution quality and its influence on bullion purity.INTRODUCTION Atlantic Gold Corporation’s Moose River Touquoy Mill in Nova Scotia, Canada was commissioned in the fourth quarter of 2017 with commercial production declared in March of 2018. The 2 Mtpa process plant uses a conventional, gravity-CIL process. This site was previously mined in the 1870s. Interest waned in the early 1900s but resumed in the 1930s and the mine was brought back into production in 1935 until an underground mine collapse in 1936. This mining district became famous after CRBC radio commenced a ground breaking, around the clock, broadcast of the rescue operations. Over 100 million people listened to the broadcast from Canada, the United States and the United Kingdom. These broadcasts changed radio, transforming it from a medium for music to on the spot, breaking news reporting. The mill was constructed by Ausenco on a fixed price EPC contract in the historic Moose River gold mining district, 95 km north-east of Halifax by road. The mill will process ore from the adjacent Touquoy pit for the first 5+ years of operation; after the Touquoy reserves are exhausted, the mill will process ore trucked 37 km from the Beaver Dam deposit for an additional 5 years."

Jan 1, 2019

By A. Vervoort, A. Govaerts

Geostatistical concepts are often difficult for students to understand, even those with a strong mathematical background. One of the main problems is the link between the variation of the parameter value in space or time and the calculated experimental semivariogram. Another challenge is differentiating between directional and omnidirectional semivariograms and their interpretation. For these reasons, interactive tools were developed based on the free public domain software R. The use of these interactive tools is limited to educational situations only (i.e., to visualize basic concepts). The interactive modules can be accessed at www.bwk.kuleuven.be/geostatistics.

Jan 1, 2014

By P. A. Mascaró, N. Chacon, A. A. Cecchi

"This document shows the development of a system called the “On-line charge level determination in SAG mills” (abbreviated as Jc). The Jc variable has certainly been difficult to measure due to the relevant number of factors and variables that affect the grinding phenomena inside semi autogenous (SAG) mills. To assess the feasibility stage of the proposed system, it was necessary to carry out two tests in different sized SAG mills, 38´ × 22´ and 36´ × 15´, respectively. In each test, the system was configured with a battery of sensors of the following types: (1) strain gauge, (2) accelerometer, and (3) gyroscope. The first step involved for charge level determinations was to determine kidney foot and shoulder by means of a study of the energy-impacts on shell structures. The second step consisted of correlating the measured grinding operational variables with the actual charge levels obtained from SAG mill crash stops. This system development is extremely useful and relevant for providing approximations about mass balances inside SAG mills. It will be a suitable tool for explaining “tonnes per hour” variations and determining optimal points under various operating conditions.INTRODUCTIONThere has been a growing necessity for technologies capable of obtaining “on-line data” of the main comminution variables in order to increase throughput. Computer systems have taken an important role in providing important solutions by means of processing on-line device signals (commonly referred to as monitoring). In semi autogenous (SAG) milling, there are many examples of monitoring devices that allow the operational staff to obtain detailed information both mechanically and electronically inside a grinding circuit. In this context, a new technology has been developed to obtain “Jc total charge (%) online” in two different SAG mills called Vibro-Energy® System.As part of the analysis performed by JKsimMet® the Jb/Jc was estimated because it has an important impact on SAG mill throughput. Different scenarios were simulated and contrasted at various theoretical Jb/Jc values in a baseline circuit (Figure 1)."

Jan 1, 2016

By G. H. Blackwell

Open pit mine management must ensure that sufficient trucks are available and are being used effectively for production, and that operating costs are under continued control and review for improvements. This paper describes methods for estimating truck fleet requirements which have been used effectively at large- and medium-sized open pit mining operations. Applied to commonly available data, multiple regression analyses can indicate when mine plans should be revised toward optimizing the number of trucks required. Prediction of major cost items for budgetary purposes is addressed, along with an example of how readily available production data can be used to reduce costs systematically.

Jan 1, 1999

By M. A. Creaney

"The Construction Group is responsible for the construction of all of Placer Dome’s major projects and contributes to the development of most major feasibility studies. This group includes an international collection of Placer Dome people who have built mines in Papua New Guinea, Australia, Chile, the United States and Canada. This paper outlines the changing role of the Construction Group from the early days of single projects to today, when several projects are in various phases from feasibility to construction. The projects’ total annual budgets have from time to time exceeded one billion dollars. IntroductionAs the competition increases globally between the major gold mining companies, the impetus continues to build mines at the lowest cost with the shortest construction schedule. Placer Dome has more than met that challenge by building mines around the world at a pace that was not contemplated 15 or 20 years ago. Since 1960, Placer Dome has built 30 mines and expansions at a cost of nearly 4.5 billion dollars.In the last six years alone, Placer Dome has built 14 mines and expansions, worth 2.6 billion dollars. The company’s success is due primarily to Experience, Innovation, People and Standards.The diversity between projects, let alone the pace, has been a challenge. Placer Dome has built mines around the world in a variety of extreme climates and distinctive cultures. The construction experience gained from these projects has allowed Placer Dome to develop an extensive knowledge and data base making it easier to “fast track” projects.Through the years Placer Dome has developed a human resource base. It now has an experienced and adaptable core team of people able to set up construction projects and build mines anywhere in the world. By developing standards and systems to support the projects they can act as soon as a new project is approved, and complete the projects quickly and effectively. The result is that Placer Dome now has the construction expertise to build its own mines, giving them the competitive advantage that allows them to design and construct a mine in the least time at the lowest capital cost. This was demonstrated in March 1997 with the completion of the construction of two new mines in 12 months."

Jan 1, 1998

By D. Pacey

"This paper reviews the installation, start-up, and operation of a comprehensive monitoring and targeting management technique in which all plant utilities (i.e., electricity, natural gas, compressed air, and water) are managed as controllable resources in the same way that raw materials, mined ore, personnel and capital are managed.The essential elements of monitoring and targeting (M&T) include:•gathering in a systematic, disciplined way the utility information by energy account centres;•closely monitoring the utilities used in each centre and comparing them with production on a common time base (e.g., kWh/ton per day);•bench marking and target setting to pro-vide attainable energy reduction goals which can be further refined as they are achieved; and•establishing an implementation plant that may provide efficiency enhancing benefits to various operating areas within the plant.The M&T system will reduce utility consumption per unit of production on a continuing basis.This would translate into sustained operating cost and waste. M&T will also provide better information for assessing the plant operation and progressively implementing further enhancements."

Jan 1, 1997

By Rick Hyndman

? Context: Ø Global action on climate change ? The situation of trade-exposed industry sectors ? The federal government?s draft plan for industry ? CAPP?s position ? Canadian emissions & Canada?s Kyoto target Simple Economic Theory of Dealing with Externalities ? Put cost on emissions Ø Carbon tax Ø Emission trading with auctioned permits ? GHG costs get reflected in the prices of energy alternatives, goods & services Ø Decisions driven by changes in relative prices ? Switching to lower emission fuels ? More energy efficient ways of producing ? More energy efficient appliances, cars, housing ? Reduced demand for energy intensive goods & services ? Anticipation of higher CO2 price drives low CO2 technology Development

Nov 1, 2002

By G. P. Contractor

Many factors affect the forge ability of steels. One of the major factors is chemical composition.' This article discusses the individual effects of alloying elements and the effect of the resultant modification of microstructure onforgeability. INTRODUCTION T HE use of alloy steels is expanding considerably and the fabrication procedures for such alloys are becoming more complex. An attempt is made in this article to describe the effect of alloying elements on the hot-workability of steels. Most of the data reported here are taken from the studies of Ihrig, Clark and others (Refs. 1-4). Chemical composition is not the only controlling factor. Grain size and surface condition of the material, forging temperature, and speed of deformation are also important. Certain conclusions can be drawn regarding the effect of various alloying elements on the hot-work-ability of forging stock. The results of hot-twist tests are considered useful in this connection as the number of twists to failure has been taken as the level of forgeability at a particular temperature. The peak in the "Number of Twists -Tem--

Jan 1, 1962

By C. Hunt, J. Vivas, D. M. Allen

"In this paper we present the results of a combined remote sensing - numerical modelling study to improve our understanding of groundwater seepage in open pit and natural rock slopes, and to investigate the interaction between groundwater, in-situ stress conditions and brittle fracture. The location of seepage is a key element in the characterisation of rock slope stability in open pits and natural slopes; definition of the fracture network geometry and its inter-relationship with seepage, however, remains a challenge in engineering practice. Current techniques used to characterize groundwater seepage locations require direct access to the rock slope for a detailed and exhaustive investigation, and can be severely limited due to access and the limited coverage of the survey methods both with respect to the height and length of the sampled rock slope. Herein, we describe remote sensing methods, which allow the collection of structural and seepage information over a wide spatial area. Remote sensing techniques are shown to have the potential to provide additional insights into the orientation and general connectivity of fractures that may play a major role in the general stability of a rock slope. A preliminary methodology for the use of remote sensing in the characterization of seepage zones in a natural slope through the application of ground-based LiDAR and Infrared Thermography (IRT) is presented.One of the most challenging problems in rock slope engineering is the realistic simulation of fluid flow through fractured and deforming rock slopes. Deformation and the development of brittle fractures can cause significant local changes in the permeability and strength of the rock mass, potentially affecting rock slope performance. Understanding fluid flow through fractured and deforming rock slopes, especially in highly-stressed environments is of great importance for slope stability analysis. Changes in the interconnectivity of fractures during slope failure are an important, yet are relatively unstudied in rock slope engineering. We present the results of hydromechanical UDEC-Trigon rock slope models focussing on the potential role of brittle fracture in rock slope failure, its interaction with groundwater pressures, and the influence of the assumed in-situ stress ratio. Damage intensity parameters are used to characterize damage within different regions of a biplanar slope failure."

Jan 1, 2015

By Hani S. Mitri

Overhand cut-and-fill mining of narrow vein orebodies inevitably leads to the creation of horizontal pillars. As the thickness of the overlying crown pillar diminishes, stresses build up in the pillar. More often than not, this situation causes an increased level of seismicity and possible pillar burst. One well-known strategy to reduce the hazard of crown and sill pillar burst in cut-and-fill vein mining is that of destress blasting. The paper first reviews the methods used for the monitoring and assessment of potential pillar burst in narrow vein cut-and-fill mining. The influence of horizontal stress, mine depth and pillar thickness on stress build-up in the crown pillar is examined through a characteristic narrow vein numerical model. The paper then presents, with reference to three mine case studies, the benefits of destress blasting and the factors affecting its success as a ground control technique.

Oct 1, 2001

By O. G. Olvera, L. S. Quiroz-Castillo, P. J. Valenzuela-Guerrero, D. G. Dixon

The effect of sulfuric acid concentration on the extractions of arsenic and copper in the catalyzed batch leaching of an enargite concentrate was studied. The acid concentrations studied were 60, 45, 30 and 15 g/L. The experimental series yields maximum copper extractions of 96 to 98% in an interval of 81 - 185 h leaching time for 60 - 15 g/L initial sulfuric acid concentration; all the copper extractions plateaued after these values; the rates and plateaus of copper extraction are increased with higher acid concentrations. Arsenic extractions reached maximum values of 89% in 57 hours, 57% in 49 hours, 33% in 25 hours, and 25% in 112 hours respectively; these maximum values were followed by a steep decrease in arsenic concentration, which indicates a precipitation event occurs in the process. According to the literature and process conditions, the arsenic precipitates obtained are iron arsenates similar to scorodite. The stability of the residues was tested using the Toxicity Characteristic Leaching Procedure (TCLP) from EPA; the residues for the four concentration levels passed the TCLP test, reporting arsenic leaching values below 1 mg/L.

Jan 1, 2014

By E. Michelotti, M. Cardu

This paper presents the results of a new method that has been tested to recover metallic cobalt lost by diamond beads from rock cuttings. When dimension stones are cut using diamond wire saws, the beads become worn and, before the end of their cycle life, lose a certain amount of material; this material is prevalently made up of sintered metal and diamonds. The material is then washed away, together with rock debris, in a dilute pulp. In effect, this process involves the dispersion of economically valuable, but potentially polluting, materials (such as cobalt) that are used to confer indispensable technological features to the beads. This current research aims to develop a waste-processing pilot plant (High-gradient Magnetic Separator or HGMS) to recover metallic components from the pulp by means of a suitable separation. The research\u2019s purposes are two-fold: a. to remove the polluting components from the rock debris before their disposal and b. to start a recycling process of the valuable metals.

Jan 1, 2010

By T. Orser

In 2010 Newmont made the decision to purchase a 42 foot (ft) Semi-Autogenous Grinding (SAG) mill from Metso and a 28 Mega-Watt (MW) Gearless Mill Drive (GMD) from ABB for the Conga Project in Peru. The test and study work showed that a single line 42 ft SAG mill circuit gave the most favorable project economics in comparison to an equivalently powered single line 40 ft SAG mill circuit. This paper does not address the process design or the project economics, but instead focuses on the key aspects of the SAG mill design, GMD design and the associated component manufacturing. This paper also addresses, where applicable, the potential reliability differences between the initially proposed 40 ft SAG mill and the finally accepted 42 ft SAG mill.

Jan 1, 2012

By Tapio Leskinen, Jouko Koskinen, Timo Nlltti, Lappalainen Seppo, Pentti Vanninen

"The Courier 300 on-stream analysis system manufactured by Outokumpu has now been in operation at five of the company's concentration plants long enough to give a reliable basis for closer examination of the benefits achieved in control of these processes. The first system was installed at the Pyhiisalmi mine at the end of 1967. Since November 1970, two analyzers have been in operation at Pyhiisalmi feeding the assay data to a process computer which controls the whole plant and does the optimization of the process. In October 1970 the Courier 300 analysis system was installed at S. T. O. LESKINEN J. KOSKINEN the Keretti concentrator of the Outokumpu mine, followed soon by installations at the Vihanti Mine in May 1971, at the new Vuonos mine in November J 971 and at t he Kotalahti mine in December 1971. Since installation of the Courier analysis systems, considerable improvements have been achieved in the control and the economy of the plants. Immediate knowledge of the changes in the process and the possibility for rapid action has resulted in evener production and higher capacity and recovery. The recovery has been increased most significantly at the Vihanti concentrator, which operates on a complex ore. Consumption of chemicals has been reduced at all concentrators. Due to the fact that process control and partly also bilance analysis are not achieved by conventional methods any more, it has been possible to reduce the personnel of the laboratories drastically. Two of the plants, viz. the Pyhiisalmi and the Vuonos concentrators, are computercontrolled. The Vuonos concentrator started operation in January 1972 under computer control from the very beginning. The Pyhiisalmi concentrator has been computer-controlled since 1970. The Courier 300 analysis system was described in detail at the AIME Centennial Annual Meeting (1971). In this paper, less attention is paid to the analysis system. Only the sampling system of the Courier 300 is described in more detail. In the development of sampling equipment, effective use has been made of the company's wide knowledge of the problems involved and the test field offered by its concentrators. The sampling equipment includes secondary samplers and six basically different types of primary samplers, with which most sampling situations can be managed."

Jan 1, 1973

By Jean-Christophe Ehrström, Fanny Mas

"A specific test set-up has been developed to study at the lab-scale the high-temperature behavior of aluminium alloys in conditions close to those experienced by thick plates during hot-rolling. A particular attention is paid to reproducing both the stress triaxiality and strain fields that exist in plate during rolling. In addition to standard ductility measurements by means of secondary tensile tests (STT), multi-step plane strain compression (PSC) tests have been performed to mimic hot-rolling pass schedules. Tool and sample geometries were adapted to allow low h/a ratios (h= average specimen thickness, a= tool width) and thus guarantee depressive stress conditions at the center of the specimen during most of the test. Such conditions resulting in porosity opening can then be used to investigate the impact of rolling conditions on damage evolution. The mechanical testing was combined with post-mortem high-resolution ultrasonic scans allowing to detect small amounts of damage and quantify its evolution as a function of processing parameters such as strain and temperature. The test set-up was validated on two 2050-type AlCuLi alloys with different susceptibilities to high temperature embrittlement.INTRODUCTION Aluminium thick plates are widely used in the aerospace industry, mainly as semi-products to be machined for internal structure parts of wings (spars, ribs) and fuselage (frame). The conversion route of such products always involves a hot-rolling step, the conditions of which (temperature, speed, pass schedule) have to be optimized to maximize both mechanical properties and final plate quality. This goal cannot always be efficiently achieved by full-scale industrial trials as (a) cost limits the number of possible test conditions and (b) it is often difficult to change one parameter alone. That is why there is a need for laboratory-scale tests able to mimic the rolling process in terms of temperature, strain rate, stress triaxiality and deformation. Most laboratory hot-rolling mills do not adequately simulate industrial processing routes, especially in terms of heat loss, deformation speed and rolling geometry (maximum roll gap vs. work roll diameter). Concerning thick plate, it is of interest to achieve both similar deformation and L/h ratio (L=arc of contact, h=mean gauge) per pass as the industrial schedule because they are simultaneously involved in damage evolution and void closure during hot forming processes (Saby, 2014)."

Jan 1, 2018

By A. P. Fletcher, K. Croteau

The intent of this paper is to cover some aspects of preventive maintenance methods which have come into wider usage in recent years as a means of increasing operating efficiencies. Particular emphasis is placed on lubrication and related servicing.

Jan 1, 1967

By J. van Huyssteen, M. Cantor

Newmont Ghana Gold Limited's Ahafo Operation has matured from its project ramp up stage into steady state operations after three years of operation. Management focus has shifted from addressing construction and commissioning problems to optimization and improvement. This focus change has coincided with the introduction by Newmont of a Continuous Improvement (CI) program across the company which provided a project management methodology that can be used in the execution of smaller scale projects. This paper focuses on the application of CI principles at the Ahafo Plant through the discussion of several case studies that demonstrate how these principles are applied.

Jan 1, 2011

By H. L. Martin

A joint federal-provincial approach in gathering basic information from industry on mine production, concentrator operations and ore reserves, initiated during 1978, is a major step toward the goal of achieving better government-industry communication through a common data base. Information from questionnaires sent out by provincial governments is shared with the federal government; correct interpretation is ensured by mine visits conducted jointly by provincial and federal representatives. Initial focus is on nonferrous metal mines. The federal Department of Energy, Mines and Resources (EMR) is responsible for a national analysis that is aimed at the early detection of worrisome developments-and their reasons-in the flow from resources to reserves and from reserves to supply of these metals. The heart of the national analysis is the annual construction of a "monitoring curve", showing each metal's aggregated mine production as it would decrease over time if no new reserves and production capacity were to be added from the year of analysis. For a given metal, a comparison of monitoring curves from year to year can reveal early signs of supply stagnation. In anyone year, a monitoring curve in conjunction with foreseen needs for Canadian mine output will show the production gap that would have to be filled from reserves and production capacity yet to be developed. The production gaps for copper, nickel, zinc and lead, the four leading base metals mined in Canada, are shown for the 20-year period ahead, in the context of production achieved during the past 20 years. It is shown that reserve levels commensurate with likely future production levels would require that average annual reserve additions during 1978-98 exceed the average annual additions during the preceding 20 years. Reserve levels of all four metals have declined in recent years. A review of significant discoveries in the last five years suggests that this fall in reserves is not the result of a lack of exploration successes, but of stagnation in development for various economic reasons.

Jan 1, 1979

By F. Daniel Rosenkranz, Peter L. Silveston

Experiments investigating the treatment of a ground wood white water waste from an Ontario pulp and paper mill by an HVCB coal are reported. Adsorption capacity for the waste, with a soluble COD contribution of 2,100 mg/I, amounted to 0.17 per cent, by weight, of the Nova Scotia coal used. Percolation of the white water waste through a coal bed indicated that soluble COD is removed. For finely ground coals, over 90 per cent of the suspended solids in the waste are retained on the coal. Plugging of the coal bed is rapid, so that any treating process using filtration would have to renew the surface of the bed frequently.

Jan 1, 1970