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By Keith S. McIntosh

The fire assay process for the quantitative recovery of platinum group elements (PGE?s) prior to subsequent analysis traditionally is a time-consuming process. Samples derive from various ore types and contain PGE?s at the ppm or ppb levels, making concentration of the elements mandatory before assaying. Traditionally sample turn-around times are of the order of 24 hours. The whole sequence of sample preparation, fire assay and subsequent analysis of PGE?s have been automated by Anglo Platinum. Some of the major challenges on the road to automation will be discussed and the novel solutions that were implemented. The engineered solution included robotic automation of the whole sequence, from sample preparation, up to the final element by element assay. The final system allowed for rapid (less than one hour) and accurate analysis of PGE?s even in streams containing very low levels, such as flotation tailing streams and drill core samples.

Jan 1, 2006

By R. Mark, R. Richards

The Washington National Cathedral is one of the largest masonry structures in the USA, and like many of its European Gothic counterparts, it required nearly a century to construct. The design was altered during this period, resulting in greater loadings than were originally anticipated on the soil beneath the foundation. When signs of continuing differential settlement were observed in the early 1990's, the Cathedral approached the US Bureau of Mines (now the National Institute for Occupational Safety and Health (NIOSH)) for assistance in monitoring the movements of the massive towers and walls. An array of dual-axis tiltmeters was installed about 40m above ground level to measure wall and tower inclination, with the data sent over a dedicated phone line to the NIOSH Pittsburgh Research Laboratory for processing. Mechanical gages and string-potentiometers are also being used to measure motion across cracks and joints, and differential pier settlement is being monitored with optical-level surveying. Data have now been collected for almost 7 years, and they show a long-term settlement trend masked by dramatic diurnal and seasonal thermal movements. The paper discusses the major findings of the study, implications for the future of the Cathedral, and conclusions regarding the use of geotechnical monitoring at major national monuments.

By H. R. Hardy

Whether the mining engineer is concerned with stress problems in a mine at depth, the development of a new drill bit, or the efficiency of a comminution process, the mechanical properties of the rock with which he must work are of the utmost importance. One of the most popular topics in rock mechanics circles today is ?Is it possible to utilize directly parameters determined from laboratory tests on rock specimens in the analysis of mining engineering problems?? It is the author's opinion that laboratory and .field investigations have not yet reached the stage of development where this question can be answered with any degree of certainty. At present, great difficulties are involved in applying the results of laboratory tests to a mining engineering problem. However, this is due in part to the lack of detailed measurements of stress and deformation in the field and in part to the lack of development of satisfactory structural theories to correlate laboratory and field measurements. Furthermore, if mechanical properties measured in the laboratory are to be directly applied to the analysis of mining engineering problems, the critical mechanical properties must be identified, reliable test procedures must be developed and extensive test programs must be carried out.

Jan 1, 1964

By B. Das

Hematite floatability from two low grade banded iron ores of India, namely banded hematite quartzite (BHQ) and banded hematite jasper (BHJ) using fatty acids and amine as the collectors is investigated under identical physico-chemical conditions. The results indicated that hematite present in BHQ ore is easy to float using both the collectors, compared to BHJ ore. The difference of flotability between the two banded iron ores is that quartz grains are coarser and well liberated below 100 micron size in case of BHQ compared to BHJ ore. In case of BHJ ore, fine hematite and quartz grains are intimately inter-grown and are dispersed in thick jasper bands leading to liberation problems. Besides that, dusty jasper particles coat over hematite surface in case of BHJ ore during the process of grinding, which hinders specific adsorption of collector on hematite or quartz surfaces. This is substantiated by scanning electron microscopy (SEM). The flotation studies have indicated that it is possible to achieve ~64% Fe with ~67% recovery from a BHQ ore using both anionic and cationic collectors from a feed containing around 38% Fe. In contrast, the hematite recovery in BHJ ore was poor. Differences in the ore characteristics that affect the flotability of hematite present in both the ores are compared. Keywords: Banded hematite quartzite, banded hematite jasper, flotation, oleic acid, dodecylamine, QEMSCAN, Scanning electron microscope

Feb 27, 2013

By O. P. Garg

"The Iron Ore Company of Canada (IOC) operations in Labrador and Quebec, in Canada, is among the largest openpit mining complexes on a world wide basis. Since the 1981-82 recession, IOC has embarked on a comprehensive cost reduction and productivity improvement program in order to survive in the world iron ore market.This paper will outline the approach used in prioritizing the cost reduction items.IntroductionMuch of the mining industry in North America is in a crisis state. Most producers are operating at production levels well below capacity, some have been merged or sold, while others have been mothballed or closed permanently. For many of us still operating, the future is uncertain. Despite the many cutbacks and closures, there is still an abundant supply of minerals in the world market and there is almost no hope for any relief on price pressures on most mineral commodities in the near future. The Iron Ore Company of Canada (IOC) operates an iron ore mine, a concentrator and a pellet plant known as the Carol Project located in Labrador City, Newfoundland. This concentrator and the pellet plant have the annual capacity to produce 20 million and 10 million tons respectively. A company owned and operated railway links this operation with the dock terminal facilities in Sept-Iles, Quebec.In the past decade the Iron Ore Company of Canada has been one of the largest producers of iron ore products in the world. Its pellets and concentrates as well as natural ores were sold in North America, Europe and the Far East. In 1981-82, sales, particularly in North America, went into a serious decline. For almost 30 years, the gospel IOC preached to employees was ""production, production!"" There were many innovations, and millions of dollars were spent on the biggest and best equipment, on research and development, on training and developing employees."

Jan 1, 1987

By Ana Flávia Tardin Siviero

A “Terra de Sucata” é o coproduto gerado pelo processo de beneficiamento de sucata na indústria siderúrgica. Atualmente, a aplicação desse coproduto é limitada pela falta de uma caracterização completa do mesmo. Dessa forma, o presente trabalho visa à caracterização de tal material para viabilizar o levantamento das possibilidades de aproveitamento do mesmo. A amostragem foi feita em uma usina siderúrgica localizada na cidade de Cariacica, no Espírito Santo. Foram realizadas análises via Difração de Raios-X (DRX) e Microscopia Eletrônica de Varredura acoplada à Espectroscopia de Energia Dispersiva (MEV/EDS). Além disso, foram feitas a determinação de pH, distribuição granulométrica, teor de umidade, densidade e análise elementar. A partir desses experimentos, observou-se que se trata de um material bastante heterogêneo em termos de morfologia, composição e granulometria, o qual apresenta 6,43 ± 0,15 de pH, 4,53% ± 0,92% de teor de umidade e 2,25 g/cm³ ± 0,25 g/cm³ de densidade. Esse material é composto pelos elementos ferro, alumínio, silício, cálcio, zinco, magnésio, manganês, fósforo, enxofre, carbono, titânio, potássio e sódio. A partir da análise de DRX, foi possível identificar a presença das fases quartzo, hematita, calcita, óxido de ferro (II) e outras.

Oct 30, 2017

By Leonard J. Prosser, Dennis R. Dolinar, John L. Ellenberger, Gabriel S. Esterhuizen, Anthony T. Iannacchione

The room-and-pillar mining method is used extensively in underground limestone mines in the Eastern and Midwestern U.S. The rock mass is typically a near-horizontal, bedded deposit at relatively shallow depth. A survey of 34 mines was conducted in which data on roof spans, rock mass properties and support practices were collected as part of a National Institute for Occupational Safety and Health research project into ground control in limestone mines. The average room width is 13.5 m (44 ft), accommodating large mechanized equipment. The results show that the immediate roof beam can consist of many individual layers and can contain several near-vertical joints. In spite of the room widths, the roof is naturally stable in many mines. Observed roof instabilities can generally be related to excessive horizontal stresses or unfavorable geological structures that cause block fallout or beam failure of the bedded roof rocks. The survey showed that the rock mass quality of the limestone does not vary significantly throughout the Eastern and Midwestern U.S. Roof conditions and the need for support were found to be closely related to the thickness and competence of the first layer of limestone in the roof. The findings highlight the need to identify local geological structures and the roof beam characteristics so that support alternatives can be evaluated. Monitoring and observational technologies that are available for identifying potentially unstable roof are presented, which include: roof characterization using the Rock Fall Risk Index, automated logging of roofbolt hole drilling, microseismic monitoring and displacement monitoring.

By H. Ewaschuk

"INTRODUCTIONRio Algom's Stanleigh Mill in Elliot Lake began production in June of 1983. The highly instrumented mill treats uranium ore at an average rate of 3900 metric tons per day. To help ensure a good start-up and low operating costs, an extensive training program was undertaken prior to and during start-up. This presentation describes how an unconventional operating crew were combined to form an operating unit with a high efficiency in terms of production and labour utilization. I would like to point out at the outset that the operating philosophy, and the role of the supervisors and the operators as set up at Stanleigh is not unique. Indeed, I have seen the same results at a couple of small plants where efficiency meant survival. However, these situations appeared to be the exception, and it was not readily apparent how similar results could be obtained in a larger plant. A factor that existed at the time was low labour turnover. As in most parts of Canada, jobs were easy to get in the Elliot Lake camp in the late 1970's. This, and other factors, contributed to an unusually high labour turnover. This changed dramatically in the early 1980's. Indeed, Rio's two other operating mills, Quirke and Panel reduced crew sizes at this time to reduce operating costs. As a result all of Stanleigh's operators came from Quirke and Panel with experience varying from 4 to 7 years. The experience that operators had was obviously of benefit and served to reduce the scope of the training program from what would have been required with inexperienced personnel."

Jan 1, 1985

By Evelynn Stirling

Agenda ? Emissions legislation ? Cummins Tier 4 Technology ? Cummins Experience with Technology ? Operation and Maintenance Impact The Emissions Challenge ? The 2014/5 emissions regulations present the most significant challenge to our customer?s diesel powered equipment design and operation in recent history? ? ?and Cummins has the solution.

Aug 1, 2013

By K. H. McDaniel, D. M. Loring

The underground ventilation system at the Waste Isolation Pilot Plant provides unparalleled ability to ensure safety of the workers, public and environment. Although small spatially, it can vary the airflow from 66,000 acfm to 460,000 acfm. It can automatically incorporate HEPA filtration in the event of radioactive contamination. Remote-capable regulators individually control the four main splits, and can be adjusted from the surface if necessary. A ventilation remote monitoring and control system provides real-time information. Future areas of concern include DPM compliance, system psychrometry, logic-based-real-time mine ventilation simulation and automation using PLC technology. This paper discusses the evolution of this system.

Jan 1, 2002

By C. D. Shackelford, J. F. Muñoz, M. Vauclin, P. Rengifo, A. Suazo

The results of a field-scale study involving in situ leaching of copper ore tailings using sulphuric acid as the leaching agent, injection wells to introduce the leaching solution and extraction wells to recover the copper-enriched pregnant leaching solution are presented. The study was performed at an abandoned tailings disposal site using a battery of injection and extraction wells. The medium was characterized through the determinations of physical, chemical, mineralogical, and hydro-dispersive properties based on laboratory and field tests, including a tritium tracer test, a pumping test, particle size analyses, and hydraulic conductivity tests. Numerous horizontal strata with different hydraulic conductivities were identified. A previously developed model was used to simulate the leaching of copper ore tailings. Although the study confirms the feasibility of using in situ leaching for recovery of residual copper from tailings deposits, the efficiency of the technology depends significantly on the medium stratigraphy and hydraulic conductivity.

Jan 1, 2001

By H. Sahay

This paper summarizes the history and ore-grade statistics of mining the Ming orebody, and then details the mining methods. Included are raising, stoping, drilling and blasting techniques. Particular attention is paid to ground support, ventilation and pumping requirements.

Jan 1, 1979

By Claudeir Carvalho Silveira

A necessidade da indústria automobilística de redução de peso, desenvolvimento de designs arrojados e aumento da resistência a corrosão dos automóveis obrigou as indústrias siderúrgicas a produzirem aços galvanizados de alta resistência. Entretanto, para que haja este desenvolvimento é necessário maior conhecimento do comportamento dos revestimentos galvanizados quando submetidos a processos de estampagem. Desgastes da superfície galvanizada, formação de pós, redução da resistência a corrosão e atrito das superfícies são aspectos importantes a considerar no projeto do ferramental de estampagem. Este trabalho teve, portanto, como objetivo a avaliação do efeito dos revestimentos Galvanizing e Galvannealed no coeficiente de atrito de um aço Dual Phase 600. Para avaliação do coeficiente de atrito foi utilizado um tribômetro de ferramenta plana que simula o atrito na estampagem de peças. O trabalho apresenta ainda a caracterização microestrutural do revestimento realizada por microscopia ótica (MO) e eletrônica de varredura (MEV) e espectroscopia de energia dispersiva (EDS). Para avaliação das propriedades do substrato e do revestimento foram utilizadas também medidas de Microdureza. Após a realização dos ensaios, foi caracterizada ainda a evolução dos revestimentos após desgaste promovido pelo tribômetro de ferramenta plana e a identificação e caracterização do fenômeno de stick-slip.

Aug 8, 2018

The pyrite-sphalerite-galena and barite orebodies at the Rosebery mine are concordant with the shale host rock and have been deformed into one system of folds with an associated axial plane cleavage. The folds are tight and overturned with east-dipping axial planes. Folds in the sulphide ore are commonly disharmonic, particularly between adjacent bands of different composition.Concentric style folds occur in the competent bands, e.g. pyrite-rich bands. Similar style folds are predominant in the less competent sphalerite-galena-rich bands and also in the shale of the host rock. The trends and plunges of the fold hinge-lines are variable but axial planes are of reasonably constant orientation throughout the mine area. The folds in the orebodies are of limited axial extent, approximating to conical folds, and are arranged in en echelon patterns. The fold system was possibly formed in one period of folding by heterogeneous strain that may have been caused by the presence of a mass of tectonically mobile sulphide ore. Lineations parallel to the ore/host rock contacts appear to reflect movement between the ore and the host rock during folding.

Jan 1, 1972

By Robert Gannicott

??A mining company without the burden of operating a mine ??Management focused on marketing a high-quality, run-of-mine range of Canadian diamonds ??Robust revenue stream ??Specialist diamond knowledge ??Canadian exploration and development expertise ??BUT ??Single asset revenue base from depleting ore reserve ??Limited influence on production plans

Apr 1, 2005

By C. Steve

ABSTRACT: In this paper, the stability evaluation and bifurcation criteria are presented for the Jinping arch dam structure. The bifurcation models in failure status of the arch dam are derived from the uniqueness of the controlling equation of dam behaviours, and the relative phenomena between positive definition of dam structural tangent stiffness and bifurcation are given in the paper. Then the structural collapse criteria for arch dam are discussed based on the energy mode. A stability criterion of dam based on the connection of yield zones is proposed according to the implementation of elasto-plastic FEM (finite element method) numerical analysis. In accordance with this judging method, nonlinear FEM analysis is used for Jinping arch dam. The failure process of the Jinping dam was simulated and yield zones were found under the overloading condition. Keywords: Stability evaluation, bifurcation, failure process, Jinping arch dam ZUSAMMENFASSUNG: In der Verliegenden Arbeit wird ein integrater geomechanisch Modellversuch fuer Jinping Bogenstaumauer Vorgesstellt. Die Bogenstaumauer liegt aut der komplizerten felsformationen. Der Zerstoerungsmechanismus, die Stabilitaetsfaktoren und die Interaktion zwischen der Bogenstaumauer und den Seiltichen. In der Vorliegenden Arbeit wird eine dreidimensionale finite element analyse fuer die seitlichen. Gestein sauflager mittels dem Bruchmodell Vorgestellt, da fuer Jiniping Bogenstaumauer angewandet wird. Ein Bruch mechanismus model einschliesslich der statistischen parameter der Gesteinfes tigkeit wird entauckeit. RÉSUMÉ: Das ce documènt a été faite une analyse d’elemt limité de trois dimensions dn fondement de construction de roche faisant appel au modéle de l’endommagemnet à fracture, analyse appliquée an fondement du bar ragevoute de Jinping. Ce documènt décrit le test de modéle géomecanique intégral pour le barrage-voûte de Jinping L’ampleur du modéle en question constitute l’une de plus importantes en China. Ils correspondent par faitement anx calculs des résultats.

Jan 1, 2003

By R. Mohan Srivastava

"The goal of estimation is considered in the light of decision analysis. A simple example reveals the essential elements of decision-making in the face of uncertainty. A second example shows that these elements are also key features of many mining decisions. These two examples cause us to revive an old probabilistic notion that the goal of estimation should be to quantify what is unknown. The conditional probability distribution provides the complete statement of one's uncertainty. Once the conditional probability distribution has been established, one should retain as an estimate the value which minimizes some objective loss function. A third example shows how the ""best"" estimate depends on the chosen loss function. Current practice is almost exclusively based on the least squares method, which assumes a loss function which penalizes underestimation and overestimation equally. This is unfortunate not only because symmetry is an unrealistic assumption but also because mining offers a rare opportunity to state the loss function directly in terms of profitability. Both the theoretical framework and the practical tools exist to allow us to reconsider the conventional notion of the ""best"" estimate. IntroductionThis paper looks at estimation in the mining industry from the point-of-view of decision analysis. Virtually all decisions depend on estimates since few of the important parameters are ever known exactly. In this paper we will be referring mainly to the estimation of ore grades, though the approach discussed here is generally applicable to any decision in which relevant information is uncertain.In the first section we look at a very simple example of decision-making in the face of uncertainty. We will then tum to a mining example and see that the essential features of the simple example still pertain. From these two examples it will be clear that the decision analysis approach rests on two key concepts: the conditional probability distribution and the loss function. A third example demonstrates how different loss functions produce different ""best"" estimates from the same conditional probability distribution. In the final sections we willexamine the current practice of estimation in the mining industry. Though the tools for estimating the conditional probability distribution already exist, a change in the way we think about ""best"" estimates is needed. Very little attention is presently paid to the loss function even though it is readily available in many mining applications."

Jan 1, 1987

By O. MacIntosh

The Round Mountain gold mine, located 90 km (55 miles) north of Tonopah, Nevada began large-scale production in 1977. During 2008 Round Mountain Gold Corporation (RMGC) relocated the primary crusher facility approximately 300 meters (1,000 feet) to make room for the next phase of open pit mining activities. This facility was installed in 1988 and used a log-crib retaining wall and dump pocket RMGC selected Hilfiker Retaining Walls and Collins Engineers, Inc. to provide design and materials for a new 17 meter (56 feet) high Mechanically Stabilized Embankment (MSE) wall to support the haul trucks at the new location. The construction contractor was EarthTech West Ltd. of Norwood, Colorado. An MSE wall with a cast-in-place concrete face was chosen as a durable, yet less expensive alternative to the reinforced concrete dump pocket that was originally designed for the project. The arrangement of the MSE wall is of an unusual configuration to meet a variety of operational and maintenance requirements. This paper outlines the selection process, design, and construction of the MSE wall.

Jan 1, 2009

By Mary Cocklan-Vendl

Regulatory processes associated with development of a world class lead-zinc mine, Red Dog Mine, in northwestern Alaska were reviewed and evaluated. Informal interviews with key project personnel, consultants, and agency field and permitting specialists provided perspective on the regulatory successes and failures of the project. Due to potential impacts to air quality, water quality, wetlands, and National Park lands, an Environmental Impact Statement was required. By developing a comprehensive baseline of information on the existing environment to aid in minimizing impacts during project siting/design and through regular coordination of evolving project plans with regulatory agencies, the mine developers were able to acquire necessary permits in a timely and cost effective manner. The only major exceptions occurred when inadequate information was collected on dispersal of airborne particulates, rates of surface water run-off, and groundwater quality. These deficiencies resulted in the need for design changes, unscheduled construction, additional environmental monitoring costs, and delays in issuance of the NPDES permit.

Jan 1, 1992

By Leandro Gustavo Mendes de Jesus

A teoria de Kubelka-Munk é bastante genérica e abrangente. A sua aplicabilidade já foi estudada nas mais diversas áreas, como tintas especiais [1], plásticos [2,3], produtos farmacêuticos [4] e alimentícios [5], e também no caolim [6-8]. A partir da teoria pode se relacionar a reflectância difusa com a função de Kubelka-Munk É também notável que carvões com elevados teores de cinza possuem propriedades colorimétricas diferentes de carvões com baixos teores de cinza. Em função dessa notável diferença acredita-se poder quantificar a quantidade de cinzas a partir da reflectância em diversos comprimentos de onda. Para isso foi elaborado um roteiro de retirada da amostra e confecção de pastilhas de carvão pulverizado onde foram medidos a reflectância e o percentual de cinzas. A partir dessas medidas foi possível a obtenção de equações que modelam a função de Kubelka-Munk em função do percentual de cinzas. Apesar do baixo número de amostras coletadas foi possível se obter funções de Kubelka-Munk que se encaixaram nos dados coletados. Por fim, foi possível concluir que há possibilidade de inferir o teor de cinzas de carvão por meio da reflectância.

Aug 8, 2018