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By Gonzalo Bernstein, David G. Meadows, German Naranjo, Edgardo Tapia

"During the last decade Antofagasta Minerals’ Los Pelambres Mine has dramatically increased its ore throughput following the fast initial phase ramp up through a series of planned incremental expansions. The original 85,000 mtpd, two SAG line plant was commissioned in 1999 and rapidly exceeded nameplate tonnage in only a few months. Following this, the inclusion of a pebble crushing circuit resulted in throughputs in excess of 114,000 mtpd and a recent, final third line SAG and ball mill addition have taken the plant to over 175,000 mtpd even with increasing ore hardness and changing ore feed characteristics. The progressive changes are described in this paper together with how the technical challenges have been met.INTRODUCTIONMinera Los Pelambres is a world class copper-molybdenum operation located in the Salamanca area in Chile, in region four, approximately 500 km north east of Santiago, the capital of Chile. In the late 1990s Antofagasta Minerals developed the Minera Los Pelambres project in Chile at an investment cost of approximately $1.3 billion USDs. The project construction was successfully led and completed by Bechtel Corporation in 1999 and within a matter of months the plant was already exceeding the nameplate capacity of 85,000 mtpd. In 2001 a pebble crushing circuit was added to raise the capacity to 114,000 mtpd. In the early part of 2003-2004, it was recognized that the hardness profile was changing with depth and that in order to maintain the plant capacity additional power would be needed in the SAG mills together with upgrading of the primary crusher. In conjunction with these changes a fifth ball mill and a second primary crusher station would also need to be installed. A further detailed engineering study and evaluation was initiated by Minera Los Pelambres. This was lead by Bechtel Corporation with major design contributions from FLSmidth and Siemens in order to establish the re-powering requirements for the SAG mills. These re-powering changes together with the inclusion of a pebble crushing circuit took the plant to up to 125,000 mtpd even with harder more competent ores. Finally in the last two years an additional grinding line has been added to take the capacity to consistently over 175,000 mtpd. The third line was installed in a record time of 256 days. A schematic of the current comminution circuit, discussed in this paper, is shown in Figure 2."

Jan 1, 2012

By D. E. Salman, R. R. Maclachlan, R. J. Barclay

"There is a considerable resource of data for spherical charge cratering, both as single charges and in row-of-charge geometr(1). The data are. however, based on cratering performance to a single free planar surface.In practice. the more common circumstance involves an angular surf ace geometry. such as occurs at the toe of a bench or the wall of a stope. It is for the purpose of investigating this circumstance that the described test work was conducted.The test objectives were: (1) to observe the change in single-charge cratering performance between planesurface and angle geometry; (2) to identify the optimum performance of single charges cratering to a plane surface. cratering from a bench sub-grade position and cratering from a condition of zero sub-grade or stope wall geometry; and (3) to observe the performance of row-of-charges cratering to an angular surface at various row burials and spacing. The row charge burial and spacing dimensions were to be expressed in simple numerical multiples of single-charge depth-of-burial data."

Jan 1, 1981

By P. Mottahed, E. De Souza

One of the major unsolved problems of safe, economical roof support in the evaporite industry has been that of obtaining and maintaining anchorages in relatively soft rock. This is due to the viscoelastic and viscoplastic behaviour of salt rock and associated deposits. This paper introduces a low-cost, yieldable support mechanism, consisting of a system of buckling disks, which provides viable solutions to dynamic support. The yieldable support system offers a number of advantages in comparison with existing dynamic support systems. It is characterized by its simplicity in design and installation, repeatability in behaviour and cost effectiveness. It also has the added advantage of providing the operator with a means of assessing support behaviour and ground performance by direct visual observation of changes in disk shape. Thus, the system can be utilized as a warning mechanism of ground stress and support load conditions. Such system not only provides a feasible and more effective rock mass stabilization strategy but improves mine safety.

Jan 1, 1999

By Jeff Smith

Agenda About NORTHPARKES The NEED The INITIATIVE The SEARCH The PRODUCTS The SOLUTION The RESULTS The Northparkes copper-gold mine in Central Western NSW commenced operations in 1994. Copper concentrate is produced and shipped to smelters in Japan, China & India under long term contracts with spot sales to other Asian countries.

May 1, 2006

By N. Ahern, M. Barbanell

Mercury is often present in gold ores and can be released during processing. In view of health and environmental concerns related to mercury, the mining industry takes leadership in the responsible management of mercury. This paper reviews various aspects of mercury management, including an overview of mercury deportment in typical gold processing flowsheets; trends in mercury legislation impacting the international flow and management of mercury in the gold mining industry; and treatment, storage and disposal options for mercury and mercury containing materials.

Jan 1, 2014

By S. Balideh

A good understanding of the behavior of rock helps us to make more informed decisions regarding geo-structures. Engineers need accurate equations to calculate the strength and deformation of rock before and after failure. Previous studies explain the failure of rock to ultimate strength, and laboratory tests adequately determine the ultimate strength and deformation modulus of rock. However, there are few comprehensive equations to determine the post-failure strength and deformation of rock. Previous work shows that the post-failure behavior of rock depends on the behavior of the broken rock particles after failure. The following question is then posed: How can the post-failure behavior of rock be determined by the behavior of broken rock particles? In order to answer the question, this study pursues three objectives: (i) to explain the behavior of broken rock at low confining pressure; (ii) to estimate the behavior of broken rock via the extrapolation of scaled laboratory testing; and to suggest a procedure (iii) to outline the post-failure behavior of a rock mass at low confining pressure commensurate with the behavior of broken rock in a rock mass.

Aug 1, 2013

By D. Kong, A. Klyashtorin, L. McGilp, I. Wilson

This work reports on applying iron oxide coated sands media in an experimental permeable reactive barrier to remove uranium species from uranium containing water. A field experiment was conducted at the legacy Gunnar uranium mine & mill site that was abandoned in the 1960s with limited to no decommissioning. The flooded Gunnar mine pit presently contains about 3.2 million m3 of water contaminated by dissolved U (1.2 mg/l), Ra-226 (0.4 Bq/l), and minor concentrations of other contaminants (As, Se, etc.). The water is seeping over the pit rim into Lake Athabasca posing environmental and health concerns. Iron oxide coated sands can be used to immobilize uranium species through an adsorption process. Methods for preparation of hydrous ferric oxide sorbents and their supported forms onto silica sands are described. Fourier transform infrared spectroscopy (FTIR), and powder X-ray diffraction (pXRD) were used to characterize the physical-chemical properties of the sorbent. The monolayer uranium uptake capacity (Qm) was estimated through the Langmuir adsorption isotherm. Adsorption kinetic experiments were performed in a lab environment before moving to a field trial. Based on these lab results and the input on field-scale appropriate geometries, a pilot permeable reactive barrier was fabricated and a field test conducted near the Gunnar pit in June 2019. This pilot test provided technical data and information needed for designing a full-scale permeable barrier based on the iron oxide coated sands, which may be applied for in-situ water treatment at Gunnar and other legacy uranium sites.

Jan 1, 2020

By Leslie Gertsch

Outline First progress report ? ?Introduction ?Non-terrestrial mining ?Near-term targets ?Stages of mining ?Study procedure Capabilities needed for non-terrestrial mining ?Mining methods ?Mining unit operations ?Typical surface mine operations sequence ?Results to date General effects of gravity ?On fragmentation ?On excavation ?On transport ?Conclusions / Recommendations

May 1, 2013

"A 3-dimensional finite element model for stress/stability analysis of rock excavations in underground mines is presented. Developed for use on personal computer under OS/2 operating system, the model employs the 8-node isoparametric brick element and accounts for such loading conditions as in situ stresses and gravity loading of the rock mass. In addition, modelling of backfill in mine stopes as in situ stress-free material is incorporated. Material failure is assessed by Mohr-Coulomb or Hoek-Brown failure criterion. A mine design example is presented to illustrate the potential use of the model as a tool for stope design.IntroductionNumerical modelling of mine structures has become a vital tool for mine design in recent years. The need to maximize ore extraction ratio and to reach deeper mineral deposits underground has led the mining industry to employ numerical methods of analysis to undertake complex ground control studies in order to better understand the ground response to mining excavations and to evaluate the ground support requirements. Thanks to the rapid developments in computer technology, it is now possible to perform very comprehensive analyses including, but not limited to, 3-dimensional, elasto-plastic, or large deformation or time dependent nonlinear analyses on personal computer.During the past ten years or so, many researchers undertook 3-D finite element analyses of rock mechanics problems in mining engineering. The following is only a sample review. For example, Chan'!' used three-dimensional finite elements to study the mechanical response of jointed granite during shaft sinking at the Canadian Underground Research Laboratory. Wang et al.(2) performed 2-D and 3-D finite element analyses of room-and-pillar mining system with flat and rolling coal seams. Thatejatu used three-dimensional finite element method to examine the problem of branching tunnels. Dolezalovaw used three-dimensional finite elements for the analysis of tunnel-face advance with partial excavation as well as full-face excavation in combination with rein for cement of the face by long anchors. Peili (5) used three-dimensional finite elements for the simulation of rock-liner interaction near the tunnel face."

Jan 1, 1992

By Lynn C. Fister

"Coal is rapidly becoming a major alternative to oil. According to the World Coal Study Final Report, total world coal trade could approach one billion tons annually by the year 2000. To facilitate the increased production and export market potential of the coal producing countries, advancements must be made to improve the transportation systems. Coal slurry pipeline systems could play a significant role in achieving these market forecasts.There are three major components to a coal slurry system the preparation plant, the pipeline and the dewatering plant. The experience and expertise gained from the Consolidation Coal Company system in Ohio, the Black Mesa system in Arizona and ETSI's Coal Evaluation Plant demonstrate that slurry pipeline technology is proven and available to meet the coal transport challenge.The costs of transporting coal by slurry pipeline can offer significant savings, as about 70 per cent of its costs are fixed. The reverse is true for railroads, where 75 to 80 per cent of the costs vary with inflation. All forms of transport-rail, barge and pipeline-will be required to move the massive volumes of coal. Coal slurry systems can provide a viable transport alternative.IntroductionThe importance of coal as a major alternative to oil is now well known and accepted throughout the world. Increasing oil prices over the last eight years have had a serious effect on national economics, particularly in those countries that are heavily dependent on oil. Coal can replace oil as the principal fuel source which could support world economic growth over the next two decades. This is the main conclusion of the World Coal Study (WOCOL) Final Report, published in May 1980.The product of that report was a result of considerable deliberation by key industry leader s and energy experts. The underlying message of the World Coal Study is that our energy and economic problems can be faced with confidence if coal use doubles by the early 1990s and triples by 2000, and if steam coal trade expand s considerably."

Jan 1, 1982

By T. W. Wlodek, Zygmunt Kowalczyk

In the period from 1946 to 1964, the annual output of co al from Polish mines increased from 4 7.3 to 117.35 million tons. In this paper, the methods of bringing about this increase in productivity through the building of some twelve new collieries (producing some 15 million tons annually) and the modernization, reconstruction and extension of some thirty-six older collieries are discussed.

Jan 1, 1967

By E. F. Evoy

"The Gunnar uranium deposit was within metasedimentary rocks of the late Archaen Tazin Group. These rocks were intensely altered by albitization so that the immediate host to the ore consisted dominantly of albite, and by the subsequent introduction of calcite. The ore consisted of disseminated pitchblende and uranophane in a pipe-shaped breccia zone. Oxidation of the ore was more intense near surface than at depth, but there was no near-surface enrichment.IntroductionThe Gunnar Mine site is on the tip of Crackingstone Peninsula, on the north shore of Lake Athabasca, Province of Saskatchewan, Canada. The peninsula forms the southern part of the Beaverlodge mining area. The ore consisted of disseminated pitchblende and uranophane in brecciated metasedimentary rocks of the Tazin Group, and the deposit was characterized by extreme albitization and subsequent carbonatization of the host environment.Production from the mine began in 1954 and the ore was depleted by 1963. In that interval the deposit yielded about 5 million tonnes of ore containing about I. 75 kg/tonne U3O8. It was mined initially from an open-pit and subsequently from underground; the open-pit contributed about 55% of total tonnage. Uranium was recovered by atmospheric leaching in sulphuric acid, ion exchange concentration, and precipitation with magnesia.This paper is based on studies made during the productive life of the mine and is concerned primarily with pre-ore alteration of the rocks containing the deposit, and with the ore mineralogy."

Jan 1, 1986

By J. Fujioka, Y. F. Gu, C. Cui, D. Ping, A. Sato, H. Harada

"A new kind of cast & wrought (C&W) Ni-Co base superalloys named as ""TMW alloys"" are developed recently for compressor or turbine disks of gas turbine engines in High Temperature Materials 21 Project at National Institute for Materials Science (NIMS) in Japan. These Ni-Co base superalloys combine the characters of two kinds of y- y' two-phase alloys (Ni-base and Co-18at%Ti alloys) and have higher tensile strength and creep resistance than C&W UNDIMET 720Li superalloy."

Jan 1, 2006

By L. Chunpongtong

One of the challenges of mine planning is to determine the most cost-effective replacement time for aging equipment. The lifespan of equipment, such as haul trucks and shovels, deployed in mining operations varies due to the nature of the material and ground conditions in which it operates. For engineering economists dealing with aging equipment, the options become an economic trade-off between higher maintenance cost versus the cost of new equipment. The discount rate plays a significant role in this decision; the higher the rate, the longer the economically optimal lifespan. Therefore, the ultimate question is: ?How can the relationship between the discount rate and the economically optimal lifespan be expressed mathematically??

Aug 1, 2013

By Earle J. Klohn

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

Jan 1, 1972

By W. F. Harkness, D. Hodgkinson

"A non-destructive testing program was established at Crows Nest Resources (C.N.R.), Line Creek mining operation following an in-service fatigue failure of a front wheel spindle on a large haulage truck.This failure identified a definite need for improvements in the ultrasonic techniques used during the mandatory spindle integrity examinations. Initial investigations using common mining industry ultrasonic examination techniques showed that the smallest detectable cracks were 75 mm in length for the spindle types in service at the C.N.R. site. The Initial findings indicated that inadequate inspection technique design was the cause of the poor performance. To improve inspection reliability it was identified that improved ultrasonic techniques were required. Results using designed ultrasonic techniques were encouraging, with the detection of simulated and natural cracks 12 mm long achieved. The cost benefits associated with the extended spindle life, following the removal of these small fatigue cracks, far exceeded those of the expertise and effort necessary to implement and conduct the N.D.T. program.Introduction During 50 years of evolution, non-destructive testing (N.D. T.) has progressed from a laboratory curiosity to a well accepted and invaluable tool used in the assessment of material integrity. Unlike destructive testing, N.D.T. does not deform or render the material useless. Non-destructive tests may involve many applications, from the determination of a corrosion prevention coating thickness to the examination of a raw material for internal and external deformities.Within the mining sector, highly-stressed components will normally have been subjected to some form of non-destructive test during their manufacturing cycle. These tests are used to ensure the component does not contain material flaws whichmay be detrimental to its service performance.While the component may have assured quality when produced, deterioration by fatigue may occur during an aggressive service life. Large dynamically-loaded components such as haulage truck front wheel spindles are , in particular, prone to this service related problem."

Jan 1, 1987

By John Hartlen

"The 19th century was an ""age of gold"" and Nova Scotia experienced its share of early gold rushes. Gold mining activity in the province was focussed into three ""rushes"" which occurred, approximately, in the 1860s, 1890s and 1930s; a total recovery of 1.1 million oz. Au has been recorded. The purpose of this note is simply to chronicle the technical development of gold mining and processing in the province and to comment briefly on the recently renewed interest in this precious metal. The first public discovery of gold in Nova Scotia was made by a farmer in 1860 at Old Tangier or Mooseland, and this find sparked the province's first gold rush. The mining and milling methods of the 1860s were ingenious. Initially, arrastras, crude stone-hewn grinding mills, drawn by men, mules or horses, were widely used. Nova Scotia's first conventional stamp mill was installed at Mooseland by 1862; it was comprised of four wooden stamps and is believed to have been imported from Scotland. One of the largest waterwheels of the 1860s, reportedly 16 feet in diameter and 8 feet wide with a SO-horsepower rating, was used in the Renfrew Gold District to drive gold stamps. Steam power was also employed, and many of the engines were of native construction, as was the unit at Waverley's Lake Major Company, which had a piston 1 foot in diameter by 12 feet long and was connected to a 16-ftdiameter flywheel."

Jan 1, 1999

By K. B. Han, S. Winkler, M. J. Benoit, M. J. Worswick

"Automotive heat exchangers are fabricated by forming multi-layered aluminum (Al) alloy brazing sheets into the desired geometry and subsequently passing the assembly through a furnace for brazing. As manufacturers seek to use thinner gauge and higher strength sheet to reduce vehicle weight, forming of the Al alloy sheets has become a challenge. Warm forming has previously proven to allay these forming concerns, but no consideration was given to the effect of increasing the forming temperature on brazing. Recently, it was shown that annealed sheet was more susceptible to the detrimental phenomenon of liquid film migration (LFM) during brazing if formed above 150°C, while work hardened sheets showed no increased susceptibility to LFM with increasing forming temperature, up to 250°C. In the current study, the brazing performance of simulated battery cooling plates was investigated. The plates were fabricated both from fully annealed and work hardened sheets. Brazing was assessed by microstructural evolution during a brazing cycle. The post-brazed microstructure varied with strain and forming temperature in plates made from annealed sheets, while no variation in microstructure with location or forming temperature was observed in plates formed from work hardened sheets.INTRODUCTION Since the 1970’s, one common method of fabricating automotive heat exchangers has been by forming multi-layered aluminum (Al) alloy sheets, and subsequently brazing the formed components together in a controlled atmosphere furnace. The Al alloy sheets used are comprised of at least two Al alloys roll bonded together, but can consist of additional layers, depending on the application; at minimum, the sheets are comprised of a core and clad layer. The core layer, often an AA3xxx alloy, remains solid throughout processing and provides strength to the assembly. The clad layer is always one of the AA4xxx series alloys which, due to their high silicon (Si) content, have a melting temperature range well below that of the core alloy. When the sheet is passed through the brazing furnace, the clad alloy melts to provide the brazed joint filler metal throughout the assembly, while the core alloy remains solid. In order to achieve cost and weight savings, heat exchanger fabricators have used Al alloy sheets with reduced thickness. However, deformation and brazing of these increasingly thin components remains a concern (Zhao & Woods, 2013). Furthermore, springback has been observed after forming sheets of higher initial strength (i.e. work hardened conditions), leading to flatness issues of formed components. Consequently, the ability to form high quality brazed joints is difficult in components formed from higher strength brazing sheets."

Jan 1, 2018

By L. Mohammadi

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

May 1, 2010

By P. E. Cavanagh

FOR THE PAST seven years Mr. W. Simpson, Chief Mechanical Inspector for the Nova Scotia Department of Mines, has carried out exhaustive field trials of non-destructive inspection equipment in the coal mines of that Province. This work has demonstrated the usefulness of a number of types of non-destructive inspection when used for periodic inspection of hoisting and haulage equipment in the coal mines of Nova Scotia. As a result, the Dominion Coal Company has instituted a programme of regular preventive maintenance inspection ?by a special staff of qualified and trained men. The purpose of this present paper is to describe how non-destructive testing techniques are used on ropes, axles, couplings, and other hoisting and haulage equipment, how these methods are being used in other industries, and the expected benefits from intelligent and properly organized use of these techniques in the coal mining industry.

Jan 1, 1956