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By Ken Norris

"Campbell Mine which has been in continuous operation since 1949 has undergone numerous operational changes in the past 3 years. This paper describes the process changes which have occurred at the Campbell Mill since 1991. The paper discusses the engineering, construction and startup of the effluent treatment circuit, the new oxide filtering and merrill-crowe precipitation circuit, and the changes to the pressure oxidation circuit. Particular attention is paid to startup problems and solutions to these problems. A review of the benefits and results of these process changes is also discussed. Future changes are also briefly reviewed with anticipated goals and expectations.IntroductionCampbell Mine is a gold mine 100% owned and operated by Placer Dome Canada. It is located in Balmertown, Ontario which is located 300 kilometres northeast of Winnipeg, Manitoba. The Campbell Mine has been in continuous operation since 1949, producing nearly 8,000,000 ounces. In 1993 Campbell Mine is budgeted to produce 289, 750 ounces of gold at a cash cost of $157 US/ounce. Daily mill tonnage is budgeted for 1,430 tons/day but has milled as high as 1,600 tons/day on a consistent basis. Recovery in 1993 is 93.4% and is budgeted to average 94.5% in 1994.In the 1992 edition of the proceedings of the Canadian Mineral Processors conference I described the changes that were made at Campbell starting in 1989. This paper continues where the 1992 paper ended and discusses the changes to the Campbell mill since that lime. The changes to Campbell since January 1992 have been numerous with capital expenditure in the mill exceeding $14.1 million. This paper describes three primary projects since that lime: the effluent treatment project ($5.5 million), the oxide leach/filtering and merrill-crowe project ($4.6 million) and the pretreatment project ($2.81 million). The focus of this paper is to highlight the justification of each project, the design and engineering, and some of the initial operational problems and solutions applied to those problems."

Jan 1, 1994

By Les Gutzwiller

Fan applications in the mining industry have changed during the last 70 years. In 1922, J.R. Robinson authored a technical volume entitled Practical Mine Ventilation. At that time, atmospheric control had only recently shifted from natural to mechanical. The large, mechanical draft fans that were used then were centrifugal. The fans ran at low speeds, about300 rpm. Most were steam-engine driven. In the late 1920s and early 1930s, mines became larger, increasing the pressure and volume requirements of the fan equipment. Axial fans were designed to run at much higher speeds (710 to 880 rpm) and were driven by electric motors. They were also smaller and less expensive to install than the cumbersome centrifugal units. However, changes in mining have resulted in progressively higher static-pressure requirements. So centrifugal fans are once again proving to be a good choice.

Jan 1, 1999

By Richards S. M

The abundances and abundance relationships of lead, zinc, copper and silver in the major sulphide lenses at Broken Hill are examined, and their possible geochemical significance discussed.When expressed as atoms per cent, zinc is the most abundant base metal throughout the whole .group of orebodies, the highest average lead: zinc ratio (No. 2 lens) being about 0·45, the lowest (No. 1 lensZinc Lode group) being in the 0·12-0 ·14 range. Lead and silver are clearly higher in the lower two orebodies, but the abundance of zinc shows no apparent relationship with stratigraphical position. Among the base metals copper is conspicuously low and remarkably uniform, a feature noted in other conformable orebodies.Although, as has been recognised for many years, abundances of silver and lead, and lead and zinc, are sympathetically related, correlation within the pairs is variable and generally of low degree. Silver and lead show distinctly the better correlation, particularly in No. 3 lens. On the basis of lead: zinc ratios, No. 2' and No. 3· lenses, on the one hand, and the No. 1 lenses, Rhodonitic and Siliceous Zinc Lodes on the other, constitute two groups. However on the basis of silver : lead ratios, No. 3 lens stands alone, No. 2 lens showing clear affinities with the higher layers. Ternary relationships between copper-zinc-Iead and silver-zinc-Iead emphasize the very close constitutional relationship between the No. 1 lenses and the two "zinc lodes".The possible implications of these relationships are then discussed in the light of the' two principal theories-hydrothermal replacement or chemical sedimentation-held for the formation of the Broken Hill ores. It is pointed out that the ratios of the four metals in the ores are rather different from those found in most igneous and sedimentary rocks, and in seawater. For 'example, whereas copper and zinc are present in almost equal amounts in most terrestrial materials, copper in the ores is only about one-hundredth of the amount of zinc. Lead has increased somewhat, but the ratio of silver to lead has fallen; in spite of its recognition as a source of silver, the Broken Hill lode is impoverished in silver with respect to lead as compared with most common terrestrial materials.No solutions are offered to these prob'lems of abundance. Rather it has been the aim of the work to provide data, and to demonstrate the...

Jan 1, 1961

The need to hoist increasing loads from great depths is leading to the more general adoption of winders of the Koepe and Blair types. The trend has introduced a number of new problems in winding ropes, more particularly in the Koepe system where regular destructive tests during the life of a rope are not possible. Consequently, the importance of introducing non-destructive tests is much greater, especially so in the case of Koepe ropes used for deep winding where there are three major destructive fatiguing influences. These are rotational effects when a vertical rope is changed end-for- end each trip, the much greater range of stress to which the rope is subjected each trip as compared with drum winding, and the destructive effect of a high coefficient of friction between wheel and rope. A plea for a lower coefficient in the interest of better rope and tread life, substantiated by analysis, is made for Koepe winders operating at depth.Co-ordination of rope testing with general hoisting problems is stressed and the active participation of the Wire Rope Committee of the Australian Mineral Industries Research Association Ltd. in the promotion ofthe project is noted.The general introduction of a rope testing programme in Australia, personnel requirements and some local basic research in the subject to cope with future demands are considered.

Jan 1, 1967

By A B. Christie

Space-based synthetic aperture radar (SAR) data is becoming available over much of the world, includingNew Zealand. Radar imagery has a number of very advantageous features, including all-weather capability; it also has artifacts, such as layover, which require processing before these data may be used to best effect.   This paper gives an outline of SAR, details the image processing required, and discusses the use of the first New Zealand Japan Earth Resources-1 SAR data to aid geological mapping on the Coromandel Peninsula.

Jan 1, 1994

By G. C. Price

This study traces the development of the bucket-wheel excavator, points out the differences in the German- and American-type wheels, and gives the major design criteria and the advantages and disadvantages of bucket-wheel operations. A computer program, written in FORTRAN IV for use with an IBM 360 computer, simulates the operation of the digging components of a bucket-wheel excavator. By supplying certain mining dimensions, soil characteristics, and machine design specifications, this program will print out a time study of the various components of an operation, power calculations for the operation, and production data. This program, when combined with a truck, belt, or rail program, should be helpful in planning a complete mining system In material suitable for a bucket-wheel excavator operation.

Jan 1, 1973

By Stanley A. Schwartz

In the Piedmont, heavily loaded structures are generally supported by either drilled piers or one of several pile types. The choice of drilled piers or piles is typically one of comparative costs. The cost of a drilled pier foundation is usually the more difficult to predict because of the greater impact that variable conditions and construction monitoring have on cost. Poor specifications, related to the drilling equipment, procedures and bearing level, can also result in large cost extras. In the southern Piedmont, straight shafts are typically extended down to hard rock to achieve primary support in end-bearing: when bells are required, they are often constructed manually. In some eastern and northern Piedmont locations the thickness of the decompossed rock zone is significant and considerable skin friction can be mobilized. Typically piers are constructed in holes temporarily cased with steel liners. The bottom is cleaned of loose material and water, and then evaluated by a geotechnical engineer to confirm the design bearing pressure (and friction, where appropriate) or recommend alternative construction measures.

Jan 1, 1988

By Gennaro G. Marino

Documented case histories of surface ground movements from mine subsidence were utilized to help determine when the initial collapse of the overburden occurred above longwall panels. By studying this relationship between initial movement at the surface and the amount of face advance, the least-complex conditions exist for empirically assessing the span capacity of the overburden. The objective of this work was to obtain a better understanding of the overburden response to longwall mining. This knowledge will give a better insight on the long-term effects that different overburden types have on the stability and the subsidence potential of room and pillar mines, as well as, the influence of the overburden on subsidence over longwall panels. Theory on the overburden span capacity was developed and correlated to field observations. Data were used on the overburden lithology, depth, width, and face advance of the panel, and the subsidence conditions that were noted on the surface. The subsidence measured on the surface was used to determine when complete failure in the overburden rock had occurred. According to spans predicted by theory and the subsidence measured in the field, the competent lower units failed at a face advance less than when significant subsidence was observed on the surface. In each case studied, there were competent lower beds; however, the full overburden weight was not sustained to the point of subsidence. The best correlation with the surface movement was found with the most shallow, competent bed. Elastic plate solutions with various support conditions were found to best monitor the surface subsidence of these upper roof units.

Jan 1, 1988

By Paul N. Freeman

This paper describes the in-situ performance of two IFS powered support installations at Betws and Penallta Collieries in the South Wales Coalfield, United Kingdom. Intensive monitoring of all powered support functions, strata movement, support/strata interaction and coal seam disturbance permitted an extensive evaluation of powered support performance for all periods of the mining cycle. The influence of support design, support rating, face design, proximate strata and scam section upon support and operating performance are discussed. In-situ performance is compared to design specification and to the requirements of Production Instruction 1982/6. Aspects which show significant variation are highlighted. Particular attention is drawn to the precise analysis of support/strata interaction in the form of canopy and base loading profiles. This illustrates the influence of support rating and configuration in determining the interaction of the canopy and base with the proximate strata. Extensometric monitoring of the coalface highlights the potential zones of disturbance within the seam which allied with support position monitoring provides an accurate basis for theoretical considerations of support loading. Conclusions are drawn, the application of which may enhance the performance and operation of IFS supports in thin to medium sections.

Jan 1, 1992

By Gavin C. Dirom

? The Mining Association of British Columbia (MABC) was established through an Act of Parliament in 1901 ? The MABC represents the interests of B.C.?s ? Coal and mineral mining companies ? Smelting companies ? Advanced stage development projects ? Key areas of work: ? Environment, Health and Safety ? Policy & Government Relations ? Knowledge and Information Services

May 1, 2008

Sufficient time has elapsed since the enactment of the amendments to the mining legislation in 1981 to enable an examination to be made of the way in which the licensing system operates in practice. One of the most important decisions in resource management in New Zealand is whether or not rights of access to the resource should be conferred by the Crown upon an appropriate private sector participant. The licensing system is the means for allocating these rights of access. The manner in which the licensing system is administered, therefore, is crucial to natural resource management in New Zealand. What is the mining licensing system in New Zealand designed to achieve? This simple question admits of no easy answer. Is it the identification and development of the mineral resources of New Zealand? Are these objectives tempered by issues of resource conservation and environmental protection? Is a balance to be achieved among these competing factors? Does the legislation contain any priorities? Does the system respond in an ad hoc manner to particular facts and circumstances or does it operate within a more predictable framework? To what extent are decisions made on access to minerals with reference to the development or conservation of other resources? These questions may be summarised in the title to this paper which poses the question whether mining licences are instruments for resource management.

Jan 1, 1988

By C. S. Spirakis, A. V. Heyl

Paper presented at the conference Economic geology in Europe and beyond II, models for mineral deposits in sedimentary basins, held in Keyworth, UK, 13-14 April 1994. The modified basinal brines, containing partly oxidised sulphur species, scavenged metals from basement rocks and sediments and transported them through the host rock, which contained local concentrations of organic matter. Reacting in various ways with the mineralising solution as temperatures at the sites of mineralisation changed, organic matter caused the precipitation and dissolution of a variety of minerals in the ore zones; it was organic matter that caused all of these reactions to occur at the same sites. Thus all components of the mineralising fluid - salt, water, heat, sulphur and metals - were obtained within the ore district. The siting of the mineral districts was related to the locations of faults through U- and Th-enriched granites beneath sediments containing basinal brines, and the locations of ore deposits within the districts were controlled by local concentrations of organic matter

Apr 1, 1995

By Robert M. Funk, James E. Lawver

The development of a laboratory and pilot-scale high-tension electrostatic flowsheet for the production of iron-ore super concentrates having silica contents in the range of 0.1% is presented, A variety of hematite and magnetite ores were tested with this flowsheet, and the pertinent metallurgical data are given. The applications and limitations of this process are brought out in terms of both practical and theoretical considerations. There have been many new developments in the past few years that have required mineral beneficiation engineers to consider new techniques for iron-ore concentration. Developments in iron powder metallurgy, and particularly the making of sheet metal directly from high-purity iron-ore concentrates, and the concept of using metallized pellets as a substitute for scrap in electric-furnace steelmaking have created demands for what is commonly referred to as iron-ore superconcen-trates. In most cases, specifications for superconcentrates are that they contain less than 0.1% total gangue, with some applications requiring less than 0.05% gangue. To produce these concentrates, new and modified processes are being developed, and the three methods receiving attention as the primary concentrating methods are: 1) Magnetic separation in which dry rotor-type equipment is used for magnetite and the high-intensity magnets are used for hematite. 2) Amine flotation. 3) "High-tension" electrostatic separation (or, elec-trodynamic concentration). This paper examines the high-tension electrostatic process in terms of its limitations and abilities for the production of iron-ore superconcentrates. A technically effective and simple flowsheet was developed through laboratory and 5 and 100-ton pilot-plant studies for the production of concentrates containing from 0.02 to 0.20% SiO, with iron recoveries between 85 and 90%. The process is also shown to be economically feasible. Laboratory Test Program Separation Characteristics: The suitability of the electrostatic high-tension method for iron-ore supercon-centration stems from the fundamental mechanism governing the process, i.e., particles are separated on the basis of differences in electrical conductivities. This conductivity is a characteristic property of minerals, and if the difference between the conductivities of two min- erals is great enough, then their separation can be performed by a high-tension machine. As shown in Figs. 1 and 2, the critical factor is the time necessary for the particle charge density, which is established by a corona discharge field, to decay to a level such that the centrifugal force acting on the particle exceeds its electrostatic, or image, force. At this point, the particle can leave the rotor at some trajectory and fall into an appropriate product receptacle. This decay time is directly proportional to electrical conductivity, and the process variables, such as feed rate, rotor speed, electrode configuration, and rotor composition, are selected to optimize the ability of the separator to resolve different conductivities. Table 1 lists the measured conductivities for some of the iron and gangue minerals used in developing the flowsheet. These results were obtained by using the conductivity cell described by Lawver and Wright.' The discharge curve of most minerals that lend themselves to super concentration by high-tension is so fast that the

Jan 1, 1971

By Edgardo Orderique

El presente texto describe el modelo de desarrollo del proyecto minero Antapaccay, de forma que cada etapa en el proceso de determinación de reservas, sea rigurosamente evaluada y estimada. La secuencia comprende el programa de taladros exploratorios, explicación geológica y mineralógica del yacimiento, interpretación y modelamiento geológico, modelamiento de leyes, definición de parámetros de optimización del pit, generación del pit final, planeamiento estratégico de fases de minado y secuencia anual del mismo, siguiendo el objetivo de maximización del NPV. Asímismo, se explican los aspectos de medio ambiente y relaciones comunitarias.

Sep 9, 2007

By Bertram Price

Libby, Montana is the site of a large vermiculite deposit that was mined between 1920 and 1990 to extract vermiculite for commercial applications such as insulation, gardening products, and construction materials. The Libby vermiculite deposit also contains amphibole minerals including tremolite, actinolite, richterite, and winchite. Historically, Libby mine workers experienced high exposures to amphibole structures, and, as a group, have experienced the health consequences of those occupational exposures. It has been suggested that Libby residents also have been and continue to be exposed to amphibole structures released during the vermiculite mining operations and therefore are at increased risk for disease. The Agency for Toxic Substance and Disease Registry (ATSDR) conducted two epidemiological-type studies of residents living in Libby and the surrounding areas to assess these risks. The Environmental Protection Agency (EPA) collected and analyzed exposure data in Libby and used those data to project risks of asbestos-associated disease for Libby residents. The EPA has placed the Libby Asbestos Site, which includes the mine and the town of Libby, on its National Priority List of hazardous waste sites in need of clean up. This article presents a review of the exposure studies conducted in Libby and an analysis of health risks based on the data collected in those studies. Libby mine workers have experienced elevated levels of asbestos-associated disease as a consequence of their occupational exposures to amphibole structures. Libby residents? exposures typically are substantially lower than mine workers? historical exposures, and the health risk projections for residents are, accordingly, substantially lower. © 2007 Published by Elsevier Inc. Keywords: Libby; Montana; Vermiculite; Amphibole minerals; Asbestos; Asbestos-associated disease

Jan 1, 2007

Various steps, and complete sequences, for the recovery of lead and zinc from a mixed sulphide concentrate, high in silica and pyrite, have been tested.Oxidation steps of roasting in air or in a sulphating atmosphere and use of aqueous acidic, ammoniacal, and near neutral oxidation media were compared. Oxidation roasting or use of acidic media appeared most useful. Procedures for dissolution of zinc from calcines using sulphuric and sulphurous acid to avoid silica gelation problems are compared and a direct leaching procedure with sulphuric 'acid at controlled pH shown to be the most useful.Methods for the removal of germanium, nickel, and magnesium from zinc sulphate solutions prior to zinc electrodeposition were tested. The recoveries of zinc from ammoniacal solutions by electrolysis and distillation are compared.The dissolution of lead compounds from the residue of zinc extraction by amine and ammoniacal ammonium sulphate (AAS) solutions Was tested. Lead, sulphide was precipitated in filtera'ble form from AAS solutions. The reduction of lead sulphate to lead sulphide with sulphur was difficult, but possible. The various steps were used to deveiop five complete processing sequences, of which two were shown to be technically feasible and have potential economic viability.

Jan 1, 1975

By Victor F. Paterno

In December of 2007, a joint venture of J.F Shea, Skanska and Schiavone referred to as S-3II, was awarded a $1.15 billion (? 886,880,000) contract to construct the run-ning tunnels and station structures for the Number 7 Line Extension Project in New York City by the Metropolitan Transportation Authority Capital Construction (MTACC) and New York City Transit (NYCT). As part of the contract, a technically complex and critical connection of the new tunnel to the existing, operational 7 Line subway was required. This paper describes the innovative design approach that was conceived to carry out the underpinning and excavation works both within the east-west 7 Line subway tunnel and beneath the north-south, 4 track, 2 level Times Square Station for the A, C & E trains. This underpinning provided temporary support to the subway substructure as the grade of the tunnel invert was lowered up to 10 feet (3 meters) into the rock sub-grade to allow the future subway to pass under the basement of the world?s busiest bus terminal. In addition, the creation of a new portal connecting the existing subway tunnel and the subterranean level of the Port Authority Bus Terminal by means of underpinning structural footings and horizontal spiling/poling of existing ground will be discussed.

By W. James Marold

The New Croton Aqueduct (NCA) was the first major water supply tunnel for New York City. The 50-km (31-mi) long tunnel has 33 open shafts 6 m (20 ft) to 121 m (397 ft) deep. The tunnel and shafts are lined with brick and mortar, with cast iron lining and pressure covers in six pressurized shafts. Details of the 1895 construction are provided and compared to modern construction techniques. The paper provides rehabilitation techniques for the shafts and pressure covers, including grouting, epoxy lining, temporary bulkhead design and installation and placement of tremie concrete 98 m (320ft) below the water level in a 122 m (400ft)deep shaft using a Remote Operated Vehicle (ROV) to monitor the placement.

Jan 1, 2008

By Anna Paula Littig Berger

A remoção do fosfóro através do processo de desfosforação do ferro-gusa tem sido cada vez mais relevante, devido a influência que exerce de forma prejudicial as propriedades do aço e devido a extensão do cenário de escassez de minérios com menor teores de fosfóro. Este trabalho tem como objetivo a avaliação termodinâmica computacional de misturas a base de dolomita e finos de minério utilizadas no processo de desfosforação realizado em panela para o refino do ferro-gusa. Foi utilizado o software Factsage para avaliação termodinâmica, tendo este se mostrado eficaz na determinação da concentração de fósforo de equilíbrio no metal, fases presentes e temperatura de fusão das misturas. Verificou-se uma tendência de maiores valores de eficiência para o processo de desfosforação quando aumenta-se a razão de massa de desfosforante e massa de gusa.

Aug 17, 2017

By P. R. Jones

A computer program was written for the design of a shell and tube heat exchanger on a price optimum basis for the following conditions: (1) Triangular pitch; (2) single or multiple pass; (3) heating or cooling; (4) no change in phase; and (5) inside pumping costs immaterial. Price optimum design was obtained for four standard tube sizes and standard pitch. The inside pressure drop was fixed and outside pressure drop was computed for the optimum baffle spacing and when the baffle spacing equaled the shell diameter. Standard shells whose areas equaled or exceeded the required area were also listed. The program was made adaptable to various fluids and to various tube sizes and pitch by reading in many of the required data such as physical properties of the fluids, tube data, and standard shell data in tabular form.

Jan 1, 1968