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By Jarc H

The steeply dipping silver/lead/zinc orebodies at Mount Isa mine have been extracted most recently by a combination of cut-and-fill and open stoping methods. Bench stoping was first used at Mount Isa Mine seven years ago to allow safe extraction of a highly stressed cut-and-fill stope. Subsequent benches have shown that the method offers significant cost and safety benefits through increased productivity and reduction in man exposure. The success of benching has lead to cut-and-fill mining being replaced at Mount Isa.Significant resources have been focussed to optimise benching. This paper describes the operational, planning, and research and development aspects which have contributed to the method to date. A brief look is also taken at the future direction of benching at Mount Isa.

Jan 1, 1992

By François Girard

La zone 1 de la mine Doyon (zone altérée), se situe à l?extrémité sud de la mine et est constituée d?une série de veines étroites à fort pendage et ayant des épontes de très faible résistance. Les épontes supérieure et inférieure ont des valeurs de RQD variant de 0 à 20 lors que les valeurs de RQD de la zone minéralisée se situent entre 20 et 40. Le minerai de la zone 1 s?étend sur environ 300 m de long et sur 900 m de profondeur avec des épaisseurs variant entre 2 et 15 m. Des méthodes de minage long-trous y sont utilisées avec des accès longitudinaux ou transverses selon l?épaisseur de la zone minéralisée. L?exploitation de la zone 1 a débuté en 1991 et plus de 1,7 millions de tonnes auront été extraites à la fin 2008. Plusieurs techniques y ont été testées que ce soit au niveau du développement ou du minage afin d?améliorer la sécurité des travailleurs, de réduire la dilution des chantiers et d?en augmenter la récupération. Différentes modifications ont été apportées aux dimensions et orientations des galeries, aux patrons de forage, aux techniques de sautages, au support de terrain, à la séquence de minage et aux méthodes de remblayage. Le texte suivant élabore sur plusieurs approches utilisées lors du minage de la zone 1.

Feb 1, 2008

By C. Larsen, E. Gratch, B. Flintoff, R. Bradburn

"In 1973 Brenda Mines Limited first investigated the potential use of a process computer to aid in the development of a control system for the concentrator grinding circuit. This initial study and its results are reviewed (1) in a previous paper.Since that time the computer system and its applications have been expanded. After the initial success of grinding circuit control, a second process computer was purchased to function as a back-up device. The two processors are currently operated in a foreground-background mode which allows extensive use of the computing facility for engineering and development work as well as operator training.Because of the relative ease of expansion, the computer has been incorporated into a flotation control system as well as an electrical peak power savings program.It is the purpose of this paper to review the successful application:; of the process computer and to indicate applications which are envisaged for the future."

Jan 1, 1978

By William R. Yernberg

The combined 80th Annual Minnesota Section of SME Meeting and 68th Annual University of Minnesota Mining Symposium was held April 17 and 18, 2007, in Duluth, MN. About 350 mining industry professionals attended the conference, including engineers, executives, mining managers and suppliers from the United States, Canada, Australia, Finland and Brazil. This year’s theme was “Consolidation – Growth – Technology.” The 80th Annual Minnesota Section of SME meeting included concurrent technical papers sessions, a keynote session that featured two distinguished speakers and a general managers session in which taconite mine operators provided updates on their operations. The Minnesota Section meeting also offered an SME short course titled “Control the Feed, Control the Mill.” More than 50 individuals at-tended the short course.

Jan 1, 2007

By Alexander B. Reeb, Richard J. Varuso, George M. Filz, Jehu B. Johnson

"T-walls, which are concrete floodwalls in an inverted “T” shape, are an integral component of the Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS). In order to resist large lateral flood loads, T-walls are typically supported on long batter piles that extend through the weak and compressible clays and peats commonly encountered in southern Louisiana. Since the piles are battered, settlement of the compressible foundation soils can result in loads acting normal to the piles and induce pile bending moments. Therefore, the design of pile-supported T-walls is a complex soil-structure interaction problem that requires detailed and careful numerical analysis to accurately estimate the stresses and bending moments in the piles. For this paper, numerical analyses were performed for three cross sections that each included a two-pile T wall system that was installed within a 15-ft tall new levee embankment. The cross sections were identical except that the elevation of the T-wall base was varied. This paper discusses the analyses, and it compares the influence of settlements and flood loading on the pile stresses and bending moments. In addition, this paper includes general recommendations for the analysis and design of pile-supported T-walls in practice.INTRODUCTION AND BACKGROUNDThe recently completed Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS) includes 350 miles of levees and floodwalls and is designed to defend against a 100-year storm surge event. The floodwalls predominantly consist of I-walls and T-walls. I-walls are comprised of a sheet pile wall curtain capped with a monolithic concrete wall above grade. T-walls are similar to I-walls, but they include a wide concrete base at grade, which forms an inverted “T” shape, and they are generally supported by long batter piles that provide additional lateral and rotational stability for resisting flood loads.During Hurricane Katrina, several I-walls failed, resulting in large breaches and devastating flooding (Duncan et al. 2008, IPET 2009). T-walls on the other hand performed quite well, including T-walls that were overtopped and eroded on the protected side, yet still did not collapse. As part of the HSDRSS, more conservative designs and height restrictions were required for I-walls (USACE 2011), and a number of I-wall sections were replaced with T-walls. However, the design of pile-supported T-walls is complex and requires careful consideration of both flood loading and settlements."

Jan 1, 2017

By Filiberto Fernández

El presente texto señala el proceso de estabilización de las altas eficiencias de corriente en la refinería de Southern Perú a través de los hornos, el desarrollo en los cátodos producidos y su apoyo del personal de mantenimiento, operaciones y producción. De forma, que utilizando esta política, la refinería ha incrementado la densidad de su corriente, controla mejor sus procesos, control físico y las pruebas de investigación en forma ordenada, eficaz y efectiva.

Sep 13, 2001

By Tingkan Lu

To understand the reinforcing mechanisms of the fully grouted resin bolt and clarify its performance in weak roof strata, the field monitoring investigation using instrumented bolts has been conducted in a coal mine. The total time of monitoring was around ten months. In the first 8 month period, the rock bolt performance relates to the initial development of the gateroad and subsequent time dependent strata response. After 8 months, the rock bolt performance relates to the effect of the approaching longwall mining operation, up to the point where the measuring station was destroyed due to the mining operation.

Jan 1, 1998

In 2005, a total of 7,111 sand and gravel mining operations reported employment to the Mine Safety and Health Administration (MSHA). ? Sand and gravel mines were the largest mining sector, comprising 48.5% of all mining operations. ? Sand and gravel mines were found throughout all 50 states and Puerto Rico.

Sep 1, 2008

By J. H. Schulman, M. H. Buckenham

R. W. Christy (Manager of Sales, Sanitary Engineering Equipment, Link-Belt Co.) and C.D. Rubert (Barrett, Haentjens & Co.) — Messrs. King and Schepman have presented an excellent paper which outlines the general practice in the design of thickener mechanisms. Lifting devices, controls, special applications and underflow pumping arrangements have been reviewed in detail. Pumping arrangements were illustrated which eliminate the need for an expensive tunnel beneath the thickener floor. Most of those illustrated have the common feature of a relatively long underflow suction line extending from the hopper floor to the pump located on the bridge at the periphery of the tank. The authors limit these arrangements to comparatively dilute or thin slurrys. It is implied that dense and coarse concentrates, which are difficult to pump, cannot be handled unless a tunnel is constructed. Fig. 1 shows an underflow pump arrangement which negates the need for a tunnel but which permits the operator to convey a heavy dense slurry. The pump is mounted directly on the fixed hoist platform and the impeller is located at the base of the steel center column. Priming water is not needed. The column

Jan 1, 1963

By Elaine T. Cullen

Miners, like many skilled blue-collar workers, are not traditional learners. They have not always been successful in classroom-type settings, preferring to learn on the job in a hands-on environment. U.S. law requires that miners have a minimum of 8 hours of safety training annually, plus 40 hours for underground miners and 24 hours for surface miners when they enter the industry. However, miners rarely view this training time positively. In fact, it has been called “safety jail” by many, who regard it as a time to get a little extra sleep While mining has become far safer in the past 100 years, it is still a dangerous occupation. The Office for Mine Safety and Health Research, a part of the National Institute for Occupational Safety and Health (NIOSH), has funded a project for the past 4 years to address this challenge. The purpose of the research was to find a way to develop effective safety training for these people. Miners are born story tellers. They share “near miss” stories, stories about master miners they have known, and stories about how things used to be. These stories not only pass along information about what will happen if a miner fails to respect the mining environment, they also instruct listeners in the culture of mining and the values that it embraces. Stories, it seems, are a way to get safety messages across to miners, especially inexperienced ones, and using older, wiser miners in these stories is an obvious choice. This paper will discuss how a series of training videos was developed, how “master miners” and story lines were chosen, and how the resulting videos have been received in the mining industry.

By James M. Franklin

Research on modern hydrothermal systems provides quantitative measures of the processes of formation of hydrothermal fluids and of precipitation mechanisms from them. Studies of ancient deposits provide new information regarding volcanological processes that are related to the deposits, as well as data on their spatial and temporal compositional variations. Mew exploration guidelines result from both aspects of research. The most fundamental requirement for large metalliferous hydrothermal systems is an abundant heat supply for the upper two kilometers of the crust. This heat may come from a focused heal source (shallow-level subvolcanic intrusion), but ambient heat also may have provided enough energy for the reactions necessary to effect leaching of metals, especially where heat flow is particularly high (i.e. very large or high-temperature magmatic source, such as ultramafic environments). For most VMS systems, the majority of the metals were derived through leaching from footwall strata; in addition interstratal fluids may enter subvolcanic intrusions during episodes of magma a chamber "cracking," engendering some '?magmatic" component in the hydrothermal system. Direct contributions of metalliferous magmatic fluid also may be significant from arc-related or back-arc felsic or alkalis systems. These latter contributions may form exceptionally high - grade portions in some deposits. Subvolcanic intrusions, which are excellent indicators of high heat flow and may have been the direct driving mechanisms for some stems undergo two stages of alteration: On intrusion emplacernent. fluids may rapidly enter and react with their mesostatic portions, evident in the sills in the Middle Valley. High temperature interactions caused albitization and destruction of oxides and sulfides, releasing metals. During terminal hydrothermal stages, the metalliferous fluid collapsed into the intrusions, forming disseminated and vein sulfides.

Jan 1, 1998

By H. Morgolin, M. A. Greenfield, P. A. Farrar

In attempts to correlate mechanical properties with microstructure, it is desirable to determine the effect of ß grain size. Determination of 6 grain size is not a problem where a has precipitated at ß grain boundaries. However, in alloys which have been processed to produce an equiaxed a +ß structure the ß grain size is difficult to determine because ß grain boundaries do not etch. The ß grain size can sometimes be laboriously determined by searching for grains which have some a! outlining the 6 grains. This difficulty of ß grain size determination in equiaxed a + ß alloys can be overcome by heating below the ß transus temperature for a short time and water quenching. Fig. 1 shows the starting equiaxed a + ß structure of the Ti-5.25A1-5.5V-0.9Fe-0.5Cu alloy used in this investigation, and Fig. 2 shows the microstructure of the same sample water-quenched after heating 1 min at 1675"F, which is 25°F below the 0 transus. The heavily etched microstructure consists of some equiaxed a! in a structure showing considerable amounts of transformed ß. The ß grain

Jan 1, 1969

By H. D. Stolovitch, M. L. Lavallée

"An engineering system used to analyze and improve the performance of industrial grinding circuits has been adapted into a training program. The systematic approach to the design of training was applied in order to:Determine if training was an appropriate and effective tool for the transfer of this new technology;Define the technical content of the program;Establish program specifications based on learner and context characteristics;Design and test prototypes of the instructional modules; and,Establish a strategy for plant implementation and maintenance of the training program.This paper thus describes how a engineering system is transferred to the workplace through the use of designed instruction.INTRODUCTIONTraining can change human performance in a permanent way. It can improve productivity for the overall benefit of an operation. Organizations can therefore use training as a mean to achieve their specific goals. Training is not the solution to every performance problem. However, in many cases, it can be a very effective way to attain desired performance.The benefits of training are often difficult to assess. However, to remain competitive, organizations must introduce new products and innovative technologies. Often, they can do both most effectively through suitable training interventions.In order for the effort and investment of training to provide optimal results, two points of view should be adopted.• An overall view of the system in which training is to be applied.• A systematic approach to the design of training (Stolovitch and Keeps, 1989)."

Jan 1, 1992

By Yoneji Kanoh, Masahiko Ohtsuka

In Japanese tunneling history, it has commonly been accepted that the long-round driving is difficult due to the complicated geological condition. Therefore, the maximum past record has been less than 3 m per round. A new record of advance was established in the 99 m2 headrace tunnel of Imaichi Water Power Station Project with an advance of 239.5 m in a month by drilling 3.9 m deep blast holes. The geology of the headrace tunnel composed of pyroxine andesite (ie. 960-1770 kg/cm2, VP3.1-4.3 km/s) which had several clay seams and open cracks and was moderately weathered. Automatic shotcrete machine was used for shotcreting. Rock support was specified according to the N.A.T.M. with each different rock type. The contractor achieved a remarkable tunneling advance not earlier experienced in Japan.

Jan 1, 1983

By George A. Lawrence, J. C. McHardy

"Field operating experience with an improved flotation mechanism for handling various flotation applications is covered in this paper. Some aspects of designing flotation machines are also presented. Operating data from extensive testing of commercial size equipment under actual plant operating conditions in the following applications is detailed:1. Copper Flotation2. Fine Coal Flotation3. Base Metal Sulfide FlotationDesign features, design improvements, modifications tested, and overall performance data are reviewed. Some mecl1anical performance data as well as metallurgical performance results are presented. Some comparisons with conventional flotation equipment are reported in this paper.Flotation sizing theories are reviewed and an actual equipment selection ex2.mple is presented. Scale-up criteria used for developing large cells are briefly covered.The paper concludes with a brief review of anticipated future flotation equipment design needs. IntroductionThe mining/milling industry is faced with increasing pressure to cut costs while maintaining product quality and indeed, in some instances, expanding production. For copper, nickel, iron, molybdenum, lead and zinc sulphides, coal, phosphate and some other minerals;, flotation remains the primary method of concentration and recovery of the valuable mineral away from the gangue. Cost reduction in flotation can be broadly focused on two areas:1. Flotation Chemicals2. Flotation Equipment"

Jan 1, 1985

By S. M. Rupprecht

A deposit to be mined by underground methods can be accessed by a number of methods: ? Adit ? Decline or ramp ? Inclined shaft ? Vertical shaft. Adits are an economical approach when the orebody is above the general floor elevation i.e. suitable in hilly or mountainous terrain. Incline shafts are limited to relatively shallow deposits, and because they are developed on an incline, development lengths for a given depth are the three to five times longer than for a vertical shaft. Vertical shafts are the preferred method for deposits deeper than 300 m but the development rate is slow and construction costs are very high. Declines or ramps offer early access to shallow deposits, which develops the ore body expediently, but are generally developed at a gradient of approximately 12 per cent. Decline haulages have become an attractive alternative to shaft hoisting, and over recent years the role of decline access has become more widespread throughout South Africa. Traditionally, South Africa has enjoyed the use of shaft systems, largely due to the large knowledge base of mining the Witwatersrand Basin, where vertical and inclined shafts were the norm. South Africa has also had the advantage of cheap electricity, giving shafts a definite economic advantage. However, in recent years the national power utility ESKOM has undergone an expansion programme that has led to tariff increases of nearly 100% over a three-year period. Based on the changes in electricity tariffs and technological improvements to underground haulage trucks, the economic inputs to access development have changed. This paper reviews mine access for shallow deposits as currently applied in South Africa. Based on current economic inputs, the paper investigates at what point a vertical shaft would be more economical than a decline system utilizing typical South African mining equipment.

Jan 1, 2012

By Dave Bulled, Khiratt Husain

"The use of High Pressure Grinding Rolls is gaining significant interest as a replacement for SAG milling in the comminution of hard rock ores because of the potential for reduced costs in terms of energy and grinding ball consumption. Estimation of expected energy consumption for fullscale operations has conventionally involved the testing of a few fairly large samples in pilot scale HPGRs. This paper describes the development of a small-scale batch test method for determining a work index for HPGR of a large number of samples that can be used to show the variability of the ore as an integral part of a geometallurgical approach to circuit design and production forecasting.The test equipment that was developed comprises a hydraulic press with adjustable pressure operating on small batches of ore in a locked cycle test procedure. A work index measurement was determined that links the specific energy consumed in the test to the breakage achieved such that the index can be used to predict comminution energy requirements.The measurements were calibrated against laboratory scale HPGR equipment to develop a model for design and forecasting that includes crushers, HPGRs and ball mills in a complete comminution circuit.INTRODUCTIONEstimation of the expected energy consumption for full-scale HPGR operations has conventionally involved the testing of a few fairly large samples in laboratory and pilot scale machines (Danilkewich, 2006). With the financial input of five mining corporations, SGS Lakefield Research has developed a small scale test capable of providing relevant information on the variability of energy consumption and size reduction from drill core samples. It is our intention that the values measured in the test will be scaled up, through benchmark comparison with pilot sized and full sized HPGR units, to allow plant design and throughput forecast on a block by block basis of the mine plan using a new CEET program. CEET® (an acronym for Comminution Economic Evaluation Tool) is an advanced grinding design and performance predicting tool that uses energy relationships to model the performance of SAG / Ball mill circuits."

Jan 1, 2008

By D. Kidby, A. Briggs

"Vitrokele ™ is a synthetic adsorbent, using chelating groups on large polystyrene beads, developed in Canada over 7 years ago, and first commercialised in 1985 to recover noxious metals from plating wastes.Pilot plant trials have been performed in Australia and Canada to demonstrate the recovery of cyanide and removal of metal cyanide complexes from gold plant effluent using Vitrokele1 M 912. The pilot plants comprise a simple adsorption train (similar to a CIP circuit) followed by complete elution facilities, so that loaded Vitrokele™ can be stripped and returned to the adsorption circuit.An account of these campaigns is provided, showing the reduction of total CN levels from over 200 ppm to less than 0.5 ppm and Cu levels from approximately 100 ppm to less than 0.3 ppm in treated tailings.Comparisons between pilot plant results and laboratory test data are given and probable future work on the process and its application to the gold mining industry is discussed.INTRODUCTIONThrough millions of years of evolution, life forms have developed specialised molecules with exceptionally high affinity and selectivity for various metals such as iron, cobalt, zinc and copper.In the early 80's professors at the Faculty of Medicine of McGill University engaged in research on the extremely efficient ways that living cells captured trace metals essential for life.As research progressed, it became evident that the special molecules used by biological systems to capture metals could be synthesized to capture selected metals with similar efficiency from water or other solutions.The technology was first commercialised in 1985 to recover noxious metals from plating wastes with compositions applying the special molecules (chelating groups) on vitreous particles (hence Vitrokele™). To date approximately three commercial Vitrokele™ plants have been installed for treating plating waters in Ontario and Quebec."

Jan 1, 1992

By Alexandra Kozak, Rodrigo Costa, Bob Fukuhara

"The Jacobina project in Bahia, Brazil commenced operations in 2004 with a design capacity of 4,200 tpd. A project development plan to increase plant capacity to 6,500 tpd will be discussed. The project included an evaluation of the existing circuit and addressed bottlenecks in the crushing, milling, sedimentation, leaching and tailings transport. These circuits and the methodology used to provide higher capacity will be presented.INTRODUCTIONThe Jacobina mine is located in the state of Bahia in northeastern Brazil approximately 330 km northwest of the state capital city of Salvador and 9 km from the town of Jacobina. The Jacobina Mine (Figure 1) is owned by Jacobina Mineração e Comércio, a wholly owned subsidiary of Yamana Gold Inc.The gold mineralization of the Jacobina mine is hosted within quartz pebble conglomerate reefs of the Serra do Córrego Formation which together with the Rio do Ouro Formation forms the Serra do Jacobina mountain chain.The Serra do Jacobina mountains have been mined for gold since the late 17th century. Since the 1970’s, the Jacobina mine has been operated by Anglo American, Williams Resources Inc., Desert Sun Mining Inc. The mine is currently owned by Yamana Gold Inc.In December of 1998, operations at Jacobina were suspended and the property was placed under care and maintenance. Desert Sun Mining Inc. began exploring the property in 2002 and eventually purchased the Jacobina mine in 2003. In 2003, a feasibility study was completed that evaluated the economics of re-developing the mining operations and expanding gold production. In 2004, refurbishment and re-development of the mining operations began and the milling facility throughput capacity was expanded from 1.08 to 1.512 Mtpy (3,000 to 4,200 tpd). The milling operations were commissioned in the 1st quarter of 2005 and commercial production was declared 1 July 2005. In April 2006, Yamana Gold Inc. acquired the Jacobina mine through its acquisition of Desert Sun Mining Inc."

Jan 1, 2008

By Deon van Tonder, Chuck Edwards

"Solvent extraction is used in many acid leach uranium circuits to upgrade and purify the uranium bearing solution prior to final product precipitation. A number of strip options are available to recover the uranium from the loaded organic. This paper compares some of these options on the basis of typical capital and operating costs for both the solvent extraction circuit and downstream uranium processing, and also considers other related issues. The aim is to provide an objective comparative assessment of these options that could be used as a qualitative guide in process selection or improvement.INTRODUCTIONIn the 1950s the uranium industry was the first industry to adopt solvent extraction (SX). Since then, the flow sheets have advanced. Notable was the introduction of tertiary amine extractants by General Mills during the late 1950s and 1960s (Mackenzie, 1997; Mackenzie, 2005), which is still today considered ‘state of the art’ technology. Initially solvent extraction was done in combination with ion-exchange, such as in the Eluex flow sheet, followed later by the adoption of direct solvent extraction from pregnant leach solution (PLS). From a strip-precipitation perspective ammonia strip followed by ammonium diuranate precipitation was widely adopted as the norm in the uranium industry. More recently alternative strip systems have been receiving increasing attention due to the environmental, health and safety issues associated with ammonia and the resulting calcined uranium oxide product. This paper explores some of these alternative options in comparison with the ammonia route.It is important to acknowledge that each operation is unique, and therefore the information and philosophy outlined in this paper serve to provide a general guide that can be potentially applied and adapted to any site or project."

Jan 1, 2013