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By B. Crane, S. Schwartz

"IntroductionThe Cape Breton Development Corporation (CBDC) located in Cape Breton, Nova Scotia, in eastern Canada, was established in 1967. Its mandate at that time was to facilitate a phased downsizing of the coal industry and developing viable replacement industries. The oil crisis in the early 1970s changed CBDC’s mandate and focus was modified to increase coal production to support Nova Scotia Power Commission’s “off oil” policy for their power generators. In the late 1980s the mandate to develop viable replacement industries was eliminated and CBDC became primarily a coal mining company. CBDC presently operates two underground coal mines, Phalen Colliery and Prince Colliery, using a retreat longwall method of mining. Both mines operate beneath the Atlantic Ocean. CBDC also operates associated infrastructure — central workshops, a railroad, coal preparation plant, and international pier. The Need For Substantial ChangeOver the last few years, CBDC has been facing some challenging issues, including improving labour management relations and achieving financial self-sufficiency and profitability. Recent achievements with regard to human resource issues, especially in the areas of collective bargaining, absenteeism, and attendance, show noticeable improvements. All participants should be commended for successfully concluding the collective bargaining process with all four CBDC unions, CUPE; CAW; IAM&AW; and UMWA. However, although these changes are encouraging, even critical in the short term, they are not sufficient to ensure the long-term viability of the company. Market ForcesShort- and long-term financial realities are drawing the need for further substantive changes. The corporation has a mandate to achieve financial self-sufficiency by the year 1999. This goal can only be achieved through a combination of cost reductions and productivity gains, specifically, a reduction in the workforce of 658 and an increase in production of 800 000 tonnes annually. This increase in productivity requires CBDC to re-think the way it does things.In the longer term, CBDC faces even greater challenges. The energy market is becoming more competitive. The electrical utilities across Canada are anticipating deregulation and are positioning themselves for the resultant competition. As primary fuel supplier to Nova Scotia Power Inc. (NSPI), the corporation will have to become ever more competitive to stay in business."

Jan 1, 1997

By K. Ananthpadmanabhan

Hydrolyzable surfactants such as fatty acids and amines undergo, in addition to micellisation and precipitation, various associative interactions in aqueous solutions to form ion molecular complexes such as acid-soap, dimers etc. depending upon the solution conditions such as pH. The interaction of these collector species with the mineral surface and with other dissolved species in solution will play a significant role in determining the interfacial processes such as adsorption and flotation. Marked differences in the hydrophobicity imparted to the mineral surface depending upon the solution conditions such as Ph can be attributed to possible differences in surface activities of the above complexes. This aspect of solution chemistry of flotation systems is discussed here for two widely used collectors namely, oleic acid and dodecylamine. Equilibrium species distribution diagrams based on the available literature .data and on estimates of energy of interactions between molecules, have been obtained for oleic acid and dodecylamine solutions.

Jan 1, 1978

By G R. Hancock, J F. Martín Duque

Post-mining landscapes are required to geomorphologically and ecologically integrate with their surrounds (Martín Duque et al., 2015). Designing and constructing an erosionally stable landform is the first and arguably most important part of the rehabilitation process. Without an erosionally stable landform topsoil and nutrients are lost, shallow groundwater is depleted as well as when excessive erosion occurs, expose suboptimal materials. Here we examine the ideas of geomorphic design and rehabilitation and how the landform can be tested and enhanced using computer based design and landscape evolution models. Specifically we evaluate the complementary capabilities of landscape modelling (SIBERIA) (Hancock and Willgoose, 2017) and geomorphic design software (Natural Regrade with GeoFluv) (Bugosh et al., 2016), in order to maximise erosional stability on post-mining landscapes (Zapico et al., 2018). CITATION:Hancock, G R and Martín Duque, J F, 2018. Geomorphic design and landscape evolution modelling for best practice mine rehabilitation, in Proceedings Life-of-Mine 2018, pp 119–121 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By Amir Zavichi

Today, with the necessity of timely, on-budget and high quality completion of projects, proper use of construction equipment is essential to ensure project success. Construction equipment places a large monetary burden on the project and if not utilized efficiently, it can result in economic losses. Cranes are one of the most important and expensive operational devices on construction sites. They play a central role, and often activities that rely on crane services fall on the project?s critical path. Currently, material-handling scheduling is done by the crane operator or by an on-duty superintendent using his/hers personal judgment, making the process manual and timeconsuming. Thus, developing an optimal schedule, which considers different dynamic constraints in construction job site, may not be possible based on the current practice. This leads to longer operation times and a negative impact on project cost. This paper presents the latest results of an ongoing study, which aims to design and implement a nearreal time crane operation decision support system to be utilized directly by the crane operator or as an aid for the superintendent in scheduling optimal operation services. This system has several advantages such as maximizing the efficiency of crane operations, guaranteeing the best operation possible to reduce the crane?s travel time, reducing crews and equipment idle time, and minimizing the dependence on subjective human judgments.

Aug 1, 2013

By I Gray

While in some cases it is vitally important to measure the virgin stress in rock prior to tunnelling there are a number of cases where such stress measurement is really not required. The concept of having to have a number to put in a numerical model representing a continuum is often quite inappropriate. This paper discusses the cases when virgin stress measurement is required and the most appropriate means to measure it. The techniques discussed cover all of the overcoring systems, hydrofracture and borehole breakout measurements. It also covers the use of rock surface stress measurement, which is easy to perform and should be used to check for changing stress conditions. Unfortunately this technique has been ignored in recent times because engineers are addicted to numerical models requiring far field stresses rather than measuring the real values that exist where they matter – at the tunnel wall. A case is presented in which the measurement of surface stress in a tunnel boring machine tunnel enabled the far field stress to be determined in what must be the world’s largest overcore.CITATION:Gray, I, 2014. The measurement of rock stress for tunnelling, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 153–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By A Deakin

It has been almost a decade since the release of the International Council of Mining and Metals (ICMM) Health and Safety Critical Control Management: Good Practice Guide (2015a). During this time the ICMM member companies, along with many others across industry, have been busy designing, deploying and enhancing their own critical control management (CCM) programs. So, what have we learnt? This paper discusses the scope, application and learnings from the implementation of CCM within the mining industry. What’s going well? What are the common challenges? What are the opportunities to strengthen the approach? What are the threats to successful implementation? The paper draws on the author’s experience as one of the key contributors to the development of the CCM Good Practice Guide and an adviser to many mining companies, including six of the ICMM members. The paper focuses on the practical (operational) application of CCM and the cycle of identifying, defining, implementing, verifying and improving critical controls at the frontline. The paper also includes a discussion on the safety performance of the ICMM member companies over the past decade and provides a recommendation for how CCM can be incorporated into a more proactive model to measure safety performance. The paper concludes with practical recommendations that mining companies, regardless of their CCM maturity, can consider as they look ahead. They are supplemented by three additional recommendations for consideration at the industry level.

Apr 16, 2024

By J. E. Pavlick, W. W. Mullins, H. W. Paxton

The growth of nitrogen-austenite during nitriding of large-gvained ferrite between 650" and 800°C has been studied as a functimz oJ time and nitrogen potential of the atmosphere for a variety of alloying elements dissolved in the ferrite. Whereas no preferential grain boundary penetration by aistenite takes place in zone-refined iron, the addition of aboit I zot pct oj' V, Ti, Cr. Si, or A1 produces significant protrusion of austenite down former 0-0 boundaries. This group of elernents also produces ragged y-0 interfaces in the a grains which advance more slozuly than those in zone-refined iron. 1 zut pct of Ni, Co, Mn, or Mo dissolved in ferrite leads to essentially smooth 7-a interfaces, which advance at rates very sinzilar to those in zone-refined iron. The reasons for this effect are not clear. Two possible limiting hypotheses, not necessarily exclusive, are discussed. One involves p.referentia1 grain bozindary diffusion of nitrogen. the other the production of a zone of ferrite, stpersatcirated with respect to nitrogen, from which austenite precipitates helerogeneozisly on the a-a gyain boundaries. In many phase transformations which occur by nu-cleation and diffusion-controlled growth, information on the parameters which control the rates of nuclea-tion and of growth is frequently not quantititative. The present work describes a continuation of efforts to obtain quantitative data on growth rates in systems where thermodynamic and kinetic factors are known independently, and thus where comparison with models of the growth process is possible. The work has been conducted on iron-base systems for two reasons. Firstly, there are several interesting transformations in this system, many of which are of practical importance. Secondly, the information on phase diagrams, activities, and diffusion coefficients is more complete in this system than in any other. These data are still inadequate to check all the effects of alloying elements, but at worst it is possible to make estimates and thus examine order-of-magni-tude agreement with proposed models. It will be necessary to do this in the present work. The problem studied was the growth of nitrogen-austenite in from the surface of large-grained columnar crystals of alloyed ferrite exposed to an NHs/Hz atmosphere. Earlier work by Grozier et al.' had suggested that growth of austenite may occur preferentially along grain boundaries of alloyed ferrite, whereas zone-refined (ZR) iron shows no such effect, Fig. 1. Growth of nitrogen-austenite into single crystals of zone-refined ferrite is planar provided sufficient nu-cleation sites for austenite are present, and is controlled by volume diffusion of nitrogen through the

Jan 1, 1967

By Everton Pizzio

Parafusos utilizados para fixação de partes submetidos a carregamentos cíclicos estão sujeitos a falhas por fadiga. No estudo do conjunto carcaça/corrediça de um compressor fixado por parafusos prisioneiros - ISO M24x3, que fixam o flange da corrediça falharam prematuramente por fadiga. O objetivo deste trabalho é desenvolver uma metodologia para otimizar o desempenho em fadiga do conjunto parafusado. Para tanto, foram realizados ensaios de fadiga visando o melhor processo de fabricação no desempenho em fadiga. Observou-se que o processo de laminação da rosca seguido de tratamento térmico é o mais adequado para o caso em estudo. A conclusão principal foi que a configuração atual de união do flange com a carcaça, resulta num baixo índice de aperto que é verificado através das cargas máximas que são transferidas diretamente ao parafuso e que aumentando o comprimento do parafuso através da inserção de uma bucha extensora, aumenta a vida em fadiga

Aug 17, 2017

By Zay Jeffries

Rearmament superimposed on buying sprees by the public, caused a general shortage of metals in 1911. and the rare metals were no exception; they also shared with the more common metals the uncertainty of future demand. In general, the apparent undersupply of metals is a favorable condition for the realization of sleeping possibilities of the rare metals, especially if the supply can he made sufficient to take care of the possible new demand. Many changes in metal usage in 1941 were forced because of shortages. When such changes are in the direction of the economic trend there is a speeding up in the tempo of the inevitable change, but when the forced changes are against the economic trend they are likely to be shortlived. In any event, the latter is not a solid foundation on which to build a future business.

Jan 1, 1942

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted, formations, an analysis was made of all .own conditions that influence flooding.

Jan 1, 1941

By Elaine T. Cullen

Safety training materials appropriate for specific underground noncoal operations in the United States are often outdated or nonexistent. The Spokane Research Laboratory (SRL) of the National Institute for Occupational Safety and H ealth has developed several new training tools, including three videos on common underground activities, software that will allow trainers to create a virtual training mine using their own mine map, and toolbox training materials. SRL is working closely with industry in the development of these tools. Teams of safety professionals are involved in the early stages, and actual mines and miners are involved throughout the production phase. This presentation describes the development process and results of SRL’s safety training projects.

By M. F. Boos

The Portland beryl-mica district, Middlesex County, Conn., comprises three deposits investigated by the Bureau of Mines in 1943. The Gotta-Walden deposit is in a pegmatite dike 4 to 20 feet thick, which cuts gneiss and schist. In general, the hanging wall is rich in mica and beryl with some feldspar, quartz, and garnet. The central core is usually high in quartz and feldspar, with relatively little mica and beryl. The footwall comprises quartz and feldspar, with varying amounts of mica and some beryl. The beryl crystals range in color from green to almost golden and have a maximum diameter of inches. Results of surface trenches indicate a beryl content of 0.81 percent for the pegmatite. A small production of beryl, feldspar, and scrap mica has been made from the deposit.

Jan 1, 1949

By C. J. Wilhelm

Brine produced from subsurface formations may be employed successfully instead of fresh water as a flooding, medium in the secondary recovery of oil. The feasibility of this substitution has been proved in the shallow "shoestring" area of eastern Kansas and northeastern Oklahoma, where the supply of fresh water often is limited. In this procedure all brine produced with the oil is returned to the formation and thus is prevented from contaminating streams and fresh-water supplies. This report includes a detailed description of a "flood project" in eastern Kansas studied by the Bureau of Mines. In an attempt to determine whether brine, when handled properly, can be used as effectively as fresh water in flooding oil from partly depleted formations, an analysis was made of all known conditions that influence flooding.

Jan 1, 1941

By C. R. Machado

Sossego Mine was the first Vale SAG mill operation to process copper-gold ore. It is located in the state of Para, in the south-eastern Amazon region of Brazil. In the first six years of continuous operation, Vale investigated different alternatives for improving circuit performance by investigating operating conditions, mainly focusing on the SAG mill. Today, after a steady increase over five years the annual production rate seems to have stabilized. It is hoped this work will show how the SAG operating practice have been perfected with time and as new data are collected. Historical data of mill grind-outs and crash stops helped create operation curves depending on the ball charge volume and total charge volume. Also noted were impacts on throughput due to the effect of reducing liner weight and the ore type characteristics.

Jan 1, 2012

By Roger Wilmoth

Exposed, open pit mine highwalls contribute significantly to the production of acid mine drainage (AMD) thus causing environmental concerns upon closure of an operating mine. Four innovative technologies were evaluated under the U.S. Environmental Protection Agency?s, Mine Waste Technology (MWTP), Prevention of AMD Generation from Open-Pit Highwalls Demonstration Project. This project is funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by the EPA and the U.S. Department of Energy (DOE) through an Interagency Agreement. The objective of the field demonstration was to evaluate the technologies ability to decrease or eliminate acid generation from treated areas of the highwall in comparison an untreated highwall area. The field demonstration was performed at the Golden Sunlight Mine (GSM) a subsidiary of Placer Dome U.S., located near Whitehall, Montana. GSM is an operating gold mine. The highwall at GSM was divided into five plots measuring 15.24 by 15.24 metres (m) and each technology was assigned a plot with the fifth plot being used for comparison as a background control plot. The four technologies were spray-applied. The applied insitu treatment technologies included: 1) A modified, furfuryl alcohol resin sealant, utilizing wood and agricultural by-products to coat the rock surface. 2) EcobondTMARD, a phosphate based process that forms a stable, insoluble compound, coating the rock surface. 3) Two ARD passivation technologies, magnesium oxide and the Dupont technology developed to create an inert layer/coating on the pyrite, preventing oxidation. The technologies were evaluated using the following methods: 1) ASTM D 5744-96, Accelerated Weathering of Solid Materials using a Modified Humidity Cells, 2) mine wall residual wall rinse sampling, 3) microscopy, and 4) core drilling followed by water injection testing.

Jan 1, 2003

By Ivette E. Torres

Aruba, formerly a. part of the Netherlands Antilles, separated on January I, 1986, and became an autonomous part of the Netherlands. Full independence of the island from the Netherlands is scheduled for 1996. In this chapter, however, Aruba's statistics are included with those of the Netherlands Antilles. Tourism continued to be the main industry of the island, which continued to depend heavily on imports, mostly from the United States. During the year, the Government was preparing legislation to regulate the exploration of oil deposits in the relatively shallow sea around Aruba.

Jan 1, 1989

By Mark Rantapaa

Measurable improvements in throughput have been documented at Barrick Goldstrike due to increased ore fragmentation through efficient drilling and blasting techniques. A decrease in throughput at the Autoclave, due to increasingly hard ore, was identified in early 2002. A team of individuals from the Open Pit and Process areas worked closely on the Drill-to-Mill (D2M) Continuous Improvement initiative to ensure that it would address the needs of both groups, with the target of actually improving throughput in future years, despite the projected harder ores. A series of tests were conducted to determine if adjustments to drilling and blasting could positively influence throughput. Better fragmentation and a subsequent increase in mill throughput were achieved through the use of: 1) Electronic caps for more precision and flexibility, as well as for allowing extremely fast shots. 2) Explosives with a higher velocity of detonation (VOD), to provide for improved shock energy. 3) Improved distribution of the explosives by decreasing pattern spacing. Early tests indicated a significant increase in throughput when processing identified harder ore. It is anticipated that the total process throughput (hard and soft ore) will increase by six tph in 2003 due to the improved fragmentation of the hard ore. Barrick Goldstrike?s D2M initiative includes roaster ?hard ore? (BWI >17), as well as autoclave ?hard ore? (BWI >15). Approximately six million tons of D2M material is expected be shot in 2003, a relatively small amount compared to the 150 million tons to be mined. The benefit of additional ounces produced should far outweigh the additional drilling and blasting costs.

May 1, 2003

By Horace Freeman

Introduction This paper is an amplification of the paper presented by the writer at the last (1930) Annual Meeting of the Institute (1), and is somewhat in the nature of a progress report upon the introduction of pyrite into the field of Canadian consumption. The burner installed at the plant of the Canada Power & Paper Corporation, St. Maurice division, has been slightly changed in dimensions and has been put into continuous operation during the past year. As predicted, it has been possible to somewhat increase the steam consumption and at the same time decrease the amount of sulphur remaining in the calcine. The grade of the sulphur-dioxide gas produced has been maintained very steadily at 12 per cent, and sufficient experience has been obtained to determine the renewal cost of continuous operation. The object of this paper now is to encourage the development of pyrite, particularly by-product flotation pyrite, as it is shown that there is a very definite field in Canada for this material and that all the previous objections to the use of pyrite have been overcome, and that the use of the material in practice in paper mills has been developed to such a point that the operation of manufacturing the sulphite cooking-liquor is as simple as, or simpler than, the present style of operation with the use of sulphur.

Jan 1, 1931

By Juliana Cecília Costa Ribeiro Vieira

Na Mina de Serra Azul da ArcelorMittal em Itatiaiuçu Minas Gerais há toda uma sistemática de controle dos processos produtivos desde a lavra, planta de concentração, estocagem, transporte ao pátio de carregamento, avaliação das características de qualidade no embarque em composições ferroviárias e assistência ao cliente no embarque do produto para a destinação final. As principais análises químicas (%) realizadas são: Fe, SiO2, Al2O3, P, Mn,TiO2, CaO, MgO e Perda Por Calcinação(PPC). Essas análises são padronizadas por normas técnicas ABNT ISO tanto para atender ao mercado interno quanto ao mercado externo. Não há como garantir a qualidade das análises se não houver uma certificação da qualidade dos padrões de referência de forma a calibrar equipamentos de análise, verificar e controlar metodologias e treinar e avaliar os analistas. A produção na Mina de Serra Azul é um processo dinâmico em constante evolução e requer uma gama grande de padrões de referência com características próprias que o mercado de material de referência não tem condições de suprir. A ArcelorMittal partiu então para desenvolver uma metodologia simplificada, mas eficiente com base em critérios estatísticos consagrados para produzir seus próprios materiais de referência secundários (ou internos) de forma a atender a sua própria demanda deste tipo de material.l

Oct 30, 2017

By Bruce K. Hebblewhite

This paper provides an overview of the international ?state of the art? with respect to underground coal mining methods used in seams of thickness greater than 4.5 m, through a review of a selection of high performing thick seam mining operations around the world?both Single Pass Longwall (SPL) and Longwall Top Coal Caving (LTCC). The paper discusses the recent operational experiences from these selected faces, together with the ground control issues faced, and identifies some of the major, inherent geotechnical factors that can influence the mining method selection, design criteria, and ultimate performance, from both an operational and safety perspective. It is clear that both of these methods are developing quickly? not only from an operational and equipment perspective, but also from the understanding of critical geotechnical criteria. There is an increasing role for both methods in thick seam environments, although the higher SPL faces will only be successful in the near to mid-term under benign geotechnical environments. Regardless of the method, a thorough understanding of the critical geotechnical factors is a key to successful implementation of either method.

Jan 1, 2013