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By H. A. Wilson

Introduction Salt (sodium chloride) occurs naturally either in the solid state as rock salt or in solution as a component of natural brines. It is the major saline constituent of sea water, which contains about 4 percent salt-roughly 164 million tons, or enough to meet world salt demands for five years, per cubic mile. The great rock salt deposits of the world are generally regarded as having been formed by the evaporation of sea water over long periods of rime in wholly, partially, or periodically cut-off bays of ancient oceans. History and Occurrence of Salt in Canada We can speak today of the vastness of Canada's salt resources, but it was not always so. Settlement of our Atlantic seaboard and the Sr. Lawrence valley began in earnest in the early 1600's. The first small commercial salt works in Canada did not come into operation until 1866. Thus, for some two and a half centuries, the inhabitants of this growing country were entirely dependent on foreign sources for every pound of salt they consumed. The record shows that from at !east 1800 onward, the need for a domestic salt industry was clearly recognized by the governments of the day. It was during the Western Ontario oil-boom of 1866 that the initial discovery of rock salt in Canada was made, not far from Goderich, at a depth of 1,000 feet. A salt company was promptly organized, and with their operations there began the gradual and still uncompleted conquest of the Canadian salt market by the Canadian salt industry. Over the next thirty years many holes were drilled into the Salina formation both in Ontario and Michigan, and encountered rock salt. A vast salt-basin was disclosed, approximately outlined, and given the name Ontario-Michigan Salt Basin. The Ontario portion of the basin extends over at least 3,500 square miles, is met with at a depth varying between 800 and 1,600 feet, and has a thickness of 50 to 250 feet. No attempt has ever been made, so far as we know, to calculate the total salt reserves of this basin, but the minimum indicated in the Ontario portion by the figures just cited is just under thirty-five cubic miles. The specific gravity of rock salt is 2.2. From these data, those so inclined may calculate the tonnage.

Jan 1, 1947

By Thomas C. Mowatt

Chemical and petrographic studies were carried out on selected tin-bearing rock samples of contact-metasomatic origin from the Cassiterite Creek and Brooks Mountain areas, Seward Peninsula, Alaska. The tin content of rocks ranged from 0.39 to 8.9 pct. Leaching with a 20 pct hydrochloric acid solution released from 19.3 to 67.9 pct of the tin. Cassiterite was not observed in the rock samples. These results are significant with regard to tin recovery and reserve delineation in these and similar occurrences. Part of this leachable tin may be associated with metasomatic borate minerals.

Jan 1, 2011

By M Salu

Ventilation control devices (VCD’s) and bulkheads are critical controls used for managing risk in underground coalmines. Following the Moura No. 2 mine explosion in 1994, the Queensland Mines Department required that the design of VCDs be based on live testing (such as in a mine testing explosion gallery) and more recently on numerical modelling using measured seal material properties. While the stipulated methods represent an idealistic solution, they are not practical to implement as solutions to daily challenges presented in underground coalmines.Not all VCD’s and bulkheads are placed in areas which have been mined to standard roadway dimensions. Operationally, VCD’s may be required to be placed close to intersections or require large dimensionally different areas (eg overcasts and pre-driven recovery road shutters) compared to the live testing or numerical modelling originally undertaken.This paper describes the various structural engineering methods utilised to account for the design of VCD’s where the operational requirements are non-standard. Siting and construction of VCD’s near the entry of cut throughs and geological structures requires additional design considerations. While VCDs constructed from a single material (eg sprayed mining plaster) are relatively straightforward to design, the addition of multiple openings (doors) or large pipes will complicate the structuralanalysis significantly.Temporary bulkheads used for the containment of grout such as for the construction of pre-driven recovery roads in coal mining have a significantly different risk profile to VCDs and should be designed accordingly. Recent failures and near-misses in such bulkheads have highlighted this issuefor the authors.The existence of an Australian Standard for Underground Mine VCDs and Bulkheads would go a long way to addressing many of the issues raised in this paper. Without a single, industry-accepted reference for VCD design, individual mines will have to continueto exercise their best judgements using whatever local expertise is available to them.

Oct 12, 2022

By Jiann-Yang Hwang, Ying Qin, Shu-Jing Zhu

Metallurgical Oil Sludge (MOS) is a byproduct created in the process of steelmaking. More than a million tons of MOS are generated each year throughout the world. The material contains hazardous components such as heavy metals and pathogenic organics, which can cause serious environmental problems and health issues. Landfill, combustion, and pyrolysis have been investigated for the disposal of MOS. However, these methods are unsatisfactory since they are unable to reach the clean environment goal. In this study, we investigate the possibility of using MOS as a reductant in a high temperature metallurgical process. The results are reported and discussed.

Jan 1, 2015

By M. Murphy

The multibillion dollar cost of cleaning up thousands of environmentally contaminated sites across the country created by decades of inadequate disposal of hazardous waste has led to a search for "deep-pocket" sources of cleanup funds. The resul1:: is the emergence of a growing body of law that could have a profound impact on commercial financing transactions and other investment activities when present or past owners of contaminated property are involved.

Jan 1, 1988

By K G. Harding, A Osman, A du Toit, F K. Crundwell, C M. Sheridan

"Most mineral processing plants have high water requirements for their operational activities. These plants often function in an environment where water is becoming increasingly scarce. An increase in population will result in an increased demand for water; potentially beyond the limits of supply and hence increased competition for the resource. In South Africa, Gauteng and the North West Province are likely to be first to experience a shortage of potable water.In order to avoid a water crisis, efforts must be made to ensure the effective management of water resources and the minimisation of wastage. Hydrometallurgical plants have a responsibility to society and the environment to operate in a sustainable manner - reducing their water requirements will certainly assist towards developing a sustainable footprint.This project improved site water management by: surveying the potable water and storm water systems with a view to assessing the current water accountability and determining methods to improve accountability determining the monthly and yearly water balance for the site and presenting it in the form of a water balance sheet drawing up an input-output and operational model in accordance with the Minerals Council of AustraliaÆs æWater Accounting Framework for the Minerals IndustryÆ calculating the water footprints of the refinery identifying ways in which water savings could be achieved recommending management systems for water usage monitoring.This work was conducted in South Africa. The value of this work lies in that it established the current baseline and assisted in developing management systems that can reduce water usage sustainably.CITATION:Osman, A, Crundwell, F K, Harding, K G, Sheridan, C M and du Toit, A, 2013. Water accountability and efficiency at a base metals refinery, in Proceedings Water in Mining 2013, pp 277-286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By J. C. Duchon

The use of extended workdays or compressed workweeks (regular shift lengths exceeding 8 h) is attracting growing interest in many industries using continuous operations. While extended workdays promise increased worker satisfaction due to more days off, including weekends and holidays, there are legitimate concerns about the potential effects on the health and safety of such a schedule. The U.S. Bureau of Mines (USBM) conducted a study at a Canadian underground copper, lead, and zinc mining operation that was designed to study the safety and performance implications of extended workdays. Measures were taken before and after a change from the old 8-h continuous schedule to the new 12-h continuous schedule, including behavioral performance measures to analyze perceptual-motor changes, continuous heart-rate monitoring and aerobic capacity to measure physical fatigue, a variety of self-report questionnaires to measure perceived adaption and satisfaction with the new schedule, and pulmonary-respiratory measures to examine air contaminant exposure. Based upon the overall acceptance of the new schedule by the workers and lack of change in fatigue-sensitive behavioral and physiological performance measures, this study recommends that the mine retain the 12-h schedule. However, certain precautionary measures are suggested to insure the safety of the workers.

Jan 1, 2010

By Giuseppe Pintaude, Carlos Mauricio Lepienski

The evaluation of the tribological behavior of thermochemically treated surfaces, such as carburising and nitriding, is of uppermost importance for the productive chain of tools, molds and matrices. However, the use of tribological tests for these surfaces should be well selected to avoid erroneous evaluations, in particular considering the effect of the substrate at different levels. In this context, the linear scratch test may be well suited to distinguish the roles of the surface and the substrate. For that purpose, this paper presents a review on the use of this type of test for tribological evaluation in terms of the performance of thermochemically treated surfaces. The approach used is multiscale, considering what types of results are obtained from each load range used and the applications for each one of them.

Nov 22, 2018

By M Hernan

Bendigo Mining Limited has established a modern underground gold mine and processing plant at Bendigo in central Victoria. The Bendigo goldfield produced around 22 000 000 oz of gold between 1851 and 1954. Approximately 4 000 000 oz were sourced from surface alluvial workings with the remaining 18 000 000 oz won from underground quartz reefs. The modern mine is accessed via the Swan Decline, which commences at the Kangaroo Flat site on the southern outskirts of Bendigo and progresses in a north easterly direction between the Deborah and Sheepshead anticlines, reaching a depth of almost 1000 m below the City of Bendigo. Development of this decline commenced in 1998. Since that time 20 km of underground development has been completed. Exploration drilling, on-reef development and bulk sampling carried out between 1999 and 2005 resulted in the estimation of a Probable Ore Reserve of 700 000 tonnes at 9.0 g/t gold for 207 000 oz of gold. These Ore Reserves were contained within four reefs located on the Deborah and Sheepshead anticlines. Reef mining commenced in late 2005 from the Shywolup and Greater Garrard reefs. Material mined was stockpiled on the surface in preparation for commissioning of the process plant which commenced in mid 2006. Mining and processing were carried out between August 2006 and May 2007 during which time 176 000 tonnes were processed at an average grade of 5.4 g/t gold to produce 26 735 oz of gold. Plant feed was sourced from four reefs. This paper discusses some of the issues which were encountered with the definition and mining of these geologically variable and nuggetty reefs. This paper covers exploration techniques, grade estimation, mine geological control, mining methods, geotechnical issues and reconciliations. It will also discuss some of the lessons learnt and how these will be applied to future Mineral Resource and Ore Reserve estimation, as well as underground operations.

Jan 1, 2008

By Aline Silva Magalhães

Os aços rápidos são assim chamados por sua capacidade de reter elevadas durezas mesmo quando submetidos a altas temperaturas, em geral decorrentes de elevadas velocidades de corte no processo de usinagem. No entanto, para que esses aços apresentem as propriedades mencionadas, faz-se necessária a combinação adequada da composição química e dos parâmetros dos tratamentos térmicos. Dentro deste contexto, o objetivo do trabalho é avaliar os efeitos da temperatura de austenitização e do tempo de encharque na têmpera na microestrutura e na dureza do aço rápido AISI M2, ligado ao tungstênio e ao molibdênio. As análises foram conduzidas através de testes de dureza e microscopias óptica e eletrônica de varredura, além de difração por raios-x, considerando três temperaturas e três tempos de austenitização. Foi observado que, de maneira geral, os valores de dureza aumentaram com a elevação da temperatura de austenitização para os três diferentes tempos de encharque utilizados, de forma concomitante com a redução na quantidade de carbonetos dispersos na matriz martensítica.

Aug 8, 2018

By Izabelle Lannes Salgueiro Ferreira

Este trabalho teve como finalidade aumentar o índice de rendimento metálico no processo de laminação à quente de aços longos no Laminador Demag, visando reduzir as perdas metálicas com maiores impactos no processo, com foco nas barras laminadas por barras perdidas. Mediante ao cenário atual da economia brasileira, o índice do rendimento metálico no processo de laminação representa um dos maiores impacto no custo de transformação do produto acabado. Para isso dividiu se o trabalho em duas fases, com aplicação da metodologia Seis Sigmas, que consiste em atuar nos problemas de forma ordenada, através da matriz de esforço x impacto. Seis sigmas é um mecanismo utilizado em melhorias de processos em geral, como forte característica identifica os parâmetros mais relevantes e influentes na geração de perdas metálicas no processo de laminação, no qual nos norteou a elaborar um plano de ação de forma sólida, ou seja, ações com menor esforço e maior impacto com foco nas causas fundamentais. Com a implementação do plano de ação, houve um aumento de 0,72% no índice do rendimento metálico para uma produção 178kt no ano 2015, com crescente melhora na performance das barras laminadas dos produtos do laminador Demag.

Aug 17, 2017

By Cristiana dos Santos Nunes

A soldagem de uniões dissimilares é muito comum em sistemas usados na exploração de petróleo e produção em águas profundas no mar. Comumente envolve soldagem de tubos de aço de baixo carbono com aços forjados baixa liga, muitas vezes, com revestimento interno de Inconel com o objetivo de reduzir o nível de tensões residuais seguidos de tratamentos térmicos de pós-soldagem. Uma técnica alternativa para reduzir as tensões residuais é utilizar um eletrodo que, durante o processo de resfriamento passa por uma transformação martensítica em uma temperatura relativamente baixa, de modo que a deformação resultante da transformação compense a contração durante o processo de resfriamento. Desta forma, o objetivo deste trabalho é avaliar o emprego do maraging como metal de solda em união dissimilar de materiais aplicadas na indústria do petróleo. Foram usados amostras de aços estruturais chanfradas em meio-v e soldadas utilizando varetas. Os níveis de tensões residuais e microestruturas da zona afetada pelo calor (ZAC) foram investigados. Uma verificação importante foi que a junta soldada apresentou tensões compressivas no metal de solda.

Aug 16, 2017

By Helder Keitaro Arçari Ambo

Aços IF (Interstitial Free) são materiais com grande capacidade de serem conformados a frio, normalmente na forma de chapas, utilizados na indústria automobilística na fabricação de carrocerias de automóveis e outros componentes similares. Neste artigo foi realizado ensaio isotérmico de dupla deformação com objetivo de determinar a fração de amaciamento que ocorre no intervalo entre passes e o parâmetro de amaciamento4. O método para obter estes dados foi utilizando software da Instron em conjunto a maquina de torção e o forno de indução. Os resultados obtidos foram de grande importância no estudo para avaliar o comportamento do material quanto aos fenômenos metalúrgicos e termomecânicos envolvidos, ou seja, se ocorre recuperação, recristalização dinâmica entre outros processos de restauração do material quando submetido a forças externas em elevadas temperaturas.

Oct 30, 2017

By K. Tarr

Acid-producing mine tailings are present at many active and inactive mine sites and pose an environmental liability due to the potential for acid rock drainage. Acid rock drainage originating from a tailings pile, a waste rock pile, or exposed sulfide-rich rock, can cause discoloration and turbidity in receiving waters, and the loading of ions mobilized by the acid can cause a decrease in aquatic flora and fauna, and reduction in the quality of groundwater. The primary cause of acid generation is the oxidation of sulfide minerals, predominantly pyrite and pyrrhotite. Considerable mine tailings are being stored on surface in vast tailings impoundment areas across Canada. In the tailings within this study, from the Sudbury, Ontario area, the sulfide mineral of primary concern with respect to acid generation is pyrrhotite. Different tailings types show varying and progressive degrees of oxidation correlating to their specific sulfur contents. The degree of oxidation is determined by the relative extent to which the sulfides have reacted as well as the depth of oxidation within the tailings. Natural Resources Canada, CanmetMINING is dedicated to research supporting the Green Mining Initiative, a program reducing business risks by demonstrating practices that reduce environmental impacts. In cooperation with the Canada Mining Innovation Council (CMIC), applied research aims to reduce land disturbance, waste volumes, and releases to the environment. By reutilizing tailings from vast impoundment areas as a component in backfill, the potential environmental impact would be lessened considerably, due to the reduced tonnage stored on surface long-term. From an operating perspective, there is a need for supplemental feed for backfill from time to time. The reclamation of old tailings for use in backfill is also driven by the fact that old tailings ponds may not be structurally stable, and it may be more cost effective to remove the tailings than to upgrade the impoundment structure. However it is imperative that these old tailings be fully characterized to determine their suitability for use underground, in order to ensure the long-term integrity of the resulting backfill matrix. A study was conducted to investigate the feasibility of tailings reclamation from old impoundment areas as a significant component in backfill. The materials were first physically and chemically characterized, followed by preparation of samples to determine optimal mix proportions for strength development for both paste and hydraulic fill compliance. It was found that the amount of oxidized tailings included in the backfill material had a profound effect on both the segregation and settling properties of the backfill matrix, as well as the mechanical properties of the samples. The strategies for decision-making, based on the criteria for material characterization, mining plan, and cost effectiveness are discussed.

Aug 1, 2013

By Larissa Mitie Ihara

Foram encontrados vários casos de falha de engrenagens de redutores de grande porte, aplicados em turbogeradores em usinas de cogeração. Este trabalho tem como objetivo a análise de falha dessas engrenagens bihelicoidais. Engrenagens operam sob condição de carregamento cíclico variável, logo seus principais modos de falha são fadiga de contato e por flexão de dentes. A engrenagem estudada, fabricada em aço 18CrNiMo7-6, foi utlizada em campo e apresentou fratura em dois dentes. Realizou-se uma análise de espectrofotometria para confirmação da composição química do material base. Uma análise microestrutural foi realizada utilizando microscopia óptica, revelando que a microestrutura corresponde a martensita com austenita retida. Foi feito um perfil de microdureza no plano transversal do dente, que indicou uma camada cementada efetiva de 2.150 µm e dureza de 715 HV0.1 na superficie. Foi feita uma fractografia macroscópica para determinação das caracteristicas da fratura, o que permitiu identificar marcas de praia e deltas de rio. Aliado a isso, foram feitas imagens por microscopia eletrônica de varredura, determinando o local do início da trinca. A partir dessas evidências, pôde-se concluir que o mecanismo de falha predominante foi fadiga por flexão de dente.

Aug 17, 2017

By Carlos Bruno Eckstein, Gabriela Ribeiro Pereira, Luís Henrique de Almeida, Clara Johanna Pacheco, Mónica Patrícia Arenas, Mariana Gaudencio B. Lima, Ana Beatriz Fonseca, Laudemiro Nogueira Júnior

Neste trabalho foi caracterizada a influência da evolução microestrutural e da composição química de aços austeníticos HP-Nb na resposta magnética detectada pela técnica de microscopia de força magnética (MFM). Além disso, também foi determinada a influência das forças eletrostáticas no sinal detectado por tal método, através da implementação da técnica de microscopia por força Kelvin (KPFM). Para este estudo, foram analisadas quatro amostras, que foram extraídas de dois tubos de reforma a vapor com diferentes composições químicas. Cada uma das amostras estudadas foi extraída de uma região do tubo exposta a diferentes temperaturas resultando em distintos estados de evolução microestrutural. Segundo os resultados obtidos, apenas as amostras com estado de envelhecimento I exibiram resposta magnética nas interfaces matriz-carbetos.

Oct 28, 2019

By Rodrigo Vitorino da Silva

Ligas a base de zircônio utilizadas na indústria nuclear estão sujeitas à formação de hidretos que são causadores de efeito deletério no material. Para aumentar o tempo de operação desses componentes, é necessário o desenvolvimento de novas ligas que retardem ou diminuam esse efeito. Este trabalho tem como objetivo avaliar a influência da adição de elementos de liga em uma liga inédita a base de Zr-Nb na absorção de hidrogênio, através de testes que avaliam a absorção de hidrogênio e a formação de hidretos no material após processamento termomecânico e comparar seu desempenho com duas ligas comerciais. Para tal, foram realizados ensaios de microdureza, cinética de absorção de hidrogênio e micrografias. Os resultados de microdureza Vickers das três ligas estudadas, após o processamento termomecânico, são muito próximos. As curvas de cinética de absorção de hidrogênio mostram que a liga Zr-Nb-Sn-Fe apresenta melhor comportamento que as demais uma vez que o tempo para o início de absorção foi maior. As micrografias indicam que a liga proposta apresenta um desempenho superior em relação à morfologia dos hidretos visto que os mesmos são mais curtos e alinhados.

Aug 17, 2017

By Anastasia Xenaki, Edmundo Laporte, Antonio Nieto, Jesus Castillo Gomez, Oscar Velasquez

It is particularly challenging for the mining industry to create and implement an efficient and adaptable mining innovation model to secure the continuous improvement of processes and products via technology. Human resource departments must play a vital role in shifting the mining culture, enabling these new classes of digitally skilled professionals to manage the mining operations of the future. This paper proposes the implementation of a concept based on the 5S mining innovation model ((a) Nieto, 2019), in a coal mining project in Central Asia, Mongolia. Practical and empirical evidence suggests that the model could serve as a roadmap to developing technologies and methods for the mines of the future.

Feb 1, 2023

By J. E. Tress

The Bureau of Mines prepared submicron tungsten powder by reducing tungsten hexachloride with hydrogen. The particle diameters of the resulting tungsten powders ranged from 0.015 to 0.046 micron. Within the limits of the variables investigated, no clear-cut correlation was found between process conditions and final size of the powder. Oxygen was the major contaminant in the product; being present both as an adsorbed gas and as suboxides of tungsten. Studies showed that the powder yielded compacts of approximately 45 per-cent of theoretical density when compacted mechanically. Low-temperature sintering produced more rapid densification in these compacts than in compacts prepared from conventional powders. Adding up to 20 percent ultrafine powder to conventional tungsten powder caused an increase in density upon compaction with maximum densification occurring at approximately 12 percent ultrafine powder.

Jan 1, 1966

By H. C. Gunning

SOME small vanadium-bearing deposits on the west coast of British Columbia about 100 miles north of Vancouver are of interest for several reasons. They are of a type that is, so far as we know, unique. They are difficult to identify as being vanadiferous so that, unless they are described, other similar deposits could easily pass unrecognized. Furthermore, although none of them has as yet been proven to be of commercial proportions, no good reason is apparent why larger, and therefore valuable, deposits should not occur under similar geological conditions. The original discovery on Quadra island was made in 1932 and has been recorded by H. V. Ellsworth and H. C. Gunning (l). Since 1932, prospecting in the area has revealed other similar deposits, one about a mile south of the original and another some ten miles to the east, near Menzies bay on Vancouver island. The Quadra Island showings are a mile and a half north of the head of Gowland harbour, a small inlet that is easily reached by gas boat from Campbell river, about four miles to the southeast on Vancouver island. The deposits were examined by the writers in the spring of 1943 in connection with field work sponsored by the Department of Geology, University of British Columbia. We are indebted to Mr. G. A. Dirom and Mr. Lothrop, of Vancouver, for helpful data on the Menzies Bay deposits, and to Dr. V. Dolmage for making a brief trip to Gowland harbour and discussing the deposits.

Jan 1, 1944