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By Pedro Hugo Tumialán

El presente texto señala el proceso de mineralización del yacimiento metálico de Algamarca en Cajamarca a través de la descripción de la singularidad de sus características geológicas. De acuerdo a ello, se corta una inclinal de cuarcita de la formación Chimú del Cretáceo inferior, cuyo eje tiene un rumbo NW concordante al eje del anticlinal. Asimismo, el intrusivo Caupur es el causante de la mineralización de las vetas de Algamarca, las cuales resultaron por fuerza de compresión perpendicular al eje del anticlinal, formando algunas vetas dextrales y sinestrales, así como vetas de tensión perpendiculares al eje anticlinal. En este sentido, las vetas son angostas (O.la 0.3 m)peroricas en plata y su distribución se da en forma de arco de cada veta.

Nov 8, 1982

By J. A. Kost

The contract objective was to evaluate the effectiveness of available dust-control technology for double-drum shearers. Eight underground surveys were conducted to evaluate drum design, drum spray nozzle locations, ranging-arm sprays, water quantity, wetting agents, and cutting techniques. The final report is made up of eight dust-control technique reports, each discussing, details of the individual mine surveys.

Jan 1, 1985

By J. N. Van der Merwe

The principal goal of the research described in the paper was to determine, by measurement of pillar scaling on pillars that have not failed, whether the pillar life prediction method developed by van der Merwe (2003) was valid as it stood or whether adjustments were necessary to the rates indirectly derived from observation of failed pillars. To this end, measurements were taken on over 350 pillars at 13sites on 6 mines. The project was done as a collaborative effort between the University of Pretoria, the Nancy School of Mines and CSIR Miningtek. During the course of the investigation, it was found that the majority of pillars display maximum scaling at mid height, that there was no clear preferential direction of pillar scaling, and that pillar corners do not scale significantly more than the mid pillar areas. The most important conclusion was that the scaling rates found by measurement agreed with the inferred rates found in the previous work. The previously developed procedure for the prediction of pillar life spans consequently requires no adjustment, although the error span is in the region of 20%. It is recommended to do further research into the effect of sealing of panels and, possible chemical changes taking place in the pillars as they age on the scaling rate.

Jan 1, 2004

By J. D. Appleton, J. Ridgway, K. B. Greally

Paper presented at the 28th International Geological Congress held in Washington DC, July 1989 (International geochemical mapping sessions). The results suggest that meaningful geochemical maps can be produced from very low-density surveys, and that existing data sets could perhaps be incorporated into such a map series with the use of a system such as Uniras software. There are still many problems to be resolved, however, including the compatibility of data derived from different analytical methods, and the precise methods to be employed will necessarily require international agreement. Sampling densities should be chosen on the basis of the scale of the geochemical and geological features to be distinguished and will vary from region to region. Reanalysis of selected samples from archives to increase the range of elements determined or to unify analytical methods is only likely to be effective if the original survey was at quite a low density

Jul 1, 1991

By William R. Yernberg

The “China & East Asia Mineral and Energy Re-sources Symposium — CEAR 2000” was held Jan. 23-26, 2000 in Denver, CO. Conference sponsors included Resources and Technology Symposia of Colorado and the Asian Journal of Mining. The meeting was attended by representatives from China, Japan, Mongolia, Korea, eastern Russia (Siberia) and the United States. The US attendees consisted of interested parties from mining and energy companies, financial institutions, consultants and government agencies. In his opening statements, L. Maness, Jr., president of Resources and Technology Symposia of Colorado, said that the “goal of the conference was to make jobs and friendships and to introduce people to each other.” The conference provided an opportunity for Western mining interests, including mining companies and investors, to meet with government agencies from both sides of the Pacific.

Jan 1, 2000

By G. Smith

This paper describes the allure of diamonds over time and highlights the magic and mystery of famous diamonds. Consideration is given to the effectiveness of marketing in the diamond industry. It is concluded that diamonds are held as cherished possessions, valued far above their real market price, retained as valued heirlooms, and widely used as a form of highly liquid currency. In order to sustain value, both from an investment and jewellery perspective, demand has been stimulated to keep pace with growing global supply while the illusion that ?diamonds are forever? has been fostered to ensure that most diamonds, once sold, do not re-enter the market.

Jan 1, 2003

By Jacques B. Wertz

Recurring movements remotely connected with the Murray fracture zone and the San Andreas fault complex, together with the slow northwestward drift affecting the Baja California peninsula, could progressively have accentuated the tensional situation already connected with the anticlinorium in southern Arizona. From the fragmentary data gathered on the Texas lineament, it appears that a very mild curvature, concave to the northeast, may be present along this belt throughout Arizona. Those localities where the successive changes in direc¬tion of the strands of the lineament belt seem to occur do generally coincide with intersections of both north-northwestern and northeastern breaks. It is along the outward, southern fringe of the belt (at such structural centers like Bisbee, Baboquivari, Ajo) that the greatest impact of regional movements could be expected to have occurred through tangential-torsional stresses. Although it si accepted that the north-northwestern and more particu¬larly the northeastern fractures in Southeast Arizona are propitious to or partially responsible for mineralization, it seems undeniable that the Texas lineament belt must have greatly increased the potentialities for ore throughout the Arizona copper province. While intrusive bodies occur near major intersections, with the Texas lineament belt as a common denominator, it seems, the ore deposits are to be found close to one of the intrusive stocks, varying in distance from contiguity (Bisbee) to one or two miles away (Silver Bell orebodies).

Jan 1, 1970

By Ranieri Corrêa Salazar

Essa contribuição técnica mostra a evolução do processo da Linha de Recozimento Contínuo de Chapas (LRCC#1) da Companhia Siderúrgica Nacional (CSN), na produção de laminados a frio sem revestimento para o segmento de mercado de tambores. A CSN vinha ao longo do tempo perdendo esse mercado devido principalmente a problemas de qualidade, como oxidação quando realizava a laminação de encruamento seca e, por outro lado quando processava o material com laminação de encruamento com óleo protetivo, ocorria no processo do cliente de cura a incompatibilidade com a tinta e vernizes nas aplicações mais críticas como acondicionamento alimentício, farmacêuticos e outros, cujos requisitos de qualidade rigorosos são exigidos contra qualquer tipo de contaminação. Desenvolveu-se um produto que associado ao controle de sua quantidade e a microgeometria da superfície da tira, resultou na lubricidade necessária para a continuidade operacional e atendeu aos requisitos de qualidade desejados.

Jul 30, 2018

By Mauro Vivaldino Fernandes

Os desafios para o aprimoramento do desempenho operacional dos altos-fornos constituem um campo aberto para o desenvolvimento e aplicação de métodos de controle que promovam a otimização da operação do reator, aliada ao prolongamento da sua vida útil. O Alto-Forno 3 da Usiminas - Ipatinga, nesta sua 4ª campanha, foi projetado para 15 anos de operação, com uma produção estimada de 41 milhões de toneladas de gusa. Os resultados da campanha atual, em termos de produção e de duração da campanha, superam os dados projetados. Neste contexto, são apresentadas as principais características do Alto-Forno 3 na sua atual campanha, a evolução do seu desempenho em termos de produtividade e tempo de operação, além das principais ações direcionadas para a preservação e estabilidade do sistema de refrigeração e do cadinho, contribuindo para o prolongamento da sua vida útil. Como resultado destes esforços, a vida útil estimada do Alto-Forno 3 é de 22 anos, superando em 7 anos a duração prevista.

Oct 30, 2017

By Dupuy. Leon W.

"INTRODUCTION For many generations the Indian tribes of the southwestern deserts knew of the thermal springs of the Coso District in southwestern Inyo County, Calif. Belief in the reputedly healing qualities of the waters and muds of the area was widespread. F. J. Sanders discovered mercury in the siliceous sinter around the hot springs while he was exploiting the district as a health resort. In searching for new domestic sources of supply of strategic minerals, authorized under the Strategic Materials Act, 3/,the Geological Survey 4/ first examined the deposits, which were drilled and sampled by the Bureau of Mines in the spring of 1941.The deposits investigated comprised three units known, respectively, as The Devils Kitchen, Nicol, and Wheeler. Most of the work was done at the first two.Of particular interest in the Bureau's work on the project was the adaptation and use of the bucket drill as a tool for sampling shallow, soft ore deposit."

Mar 1, 1948

By Hongfa Hu, Stavros A. Argyropoulos, Stephan Ferenczy

"Physical as well as mathematical modeling was carried out to investigate the exothermic mass transfer in liquid metal systems. In these systems, the exothermicity induces unique heat, mass and momentum transfer phenomena. Moreover, these phenomena are deeply coupled and they are further complicated by the presence of a moving boundary.In the physical model used, ice cylinders were immersed into sulfuric acid solutions, because the intermixing of ice with sulfuric acid is very exothermic. In this low temperature system, velocity and temperature measurements in the sulfuric acid were made as well as measurements of the ice melting in the sulfuric acid.The mathematical model developed solved simultaneously the heat, mass and momentum equations numerically, utilizing the control-volume finite difference approach. The enthalpy method was adopted to track the moving boundary. Predictions made by the mathematical model were in close agreement with the results obtained by the physical model.The results from the mathematical model were further validated with experiments involving high temperature liquid metals. Specifically, data were obtained in an experimental setup involving (a) dipping silicon cylinders into high carbon liquid iron and (b) dipping nickel cylinders into liquid aluminum. Results from these experimental studies supported the predictions of the mathematical model."

Jan 1, 1999

By Dale S. Hursh, William A. Brooks

Introduction US dependence on external energy sources is dangerous because of unstable political situations existing in key energy exporting countries. So, recent national energy policies call for increased reliance on domestic energy sources. Coal ranks as the most feasible domestic energy source due to its abundant reserves and continental distribution. But to efficiently extract these coal reserves, huge sums of capital funds are needed. Due to the depressed economy, lenders of capital funds are forced to be more stringent with loan applications. This results in fewer loans granted. In many cases, it is uncertain if funding can be obtained. Furthermore, the greatest level of domestic mine financing is expected to be in the coal sector. Demand for capital in the domestic coal industry is anticipated to increase 80% by 1990. The Chase Manhattan Bank in New York warns that these future needs cannot be met by the present capital markets. This article analyzes the current and expected situations of the capital markets available to the domestic coal industry, including: • current and expected future types of financing used in the domestic coal industry; • problems the domestic coal industry may encounter as it seeks capital; and • the future availability of capital funds as concluded from analysis of the first two items. Background Information Regardless of industry, all projects or ventures can be divided into four basic stages: generation; evaluation; selection; and execution. Within the mining industry, one can break down these stages to draw a clear picture of mine development, as shown in Fig. 1. Each successive stage has a corresponding risk level. This risk level defines the type of financing available to the mine operator. Mining Venture Risks A coal mining venture can be characterized by its unique blend of technical and financial risk. As the mine moves through different development stages, varying proportions of each of these risks are encountered. It is these risks that the lender evaluates to determine project suitability. For a coal mining venture, the major complexities generally occur with the technical risk. These include: • quantifying the coal reserves: • assessing the feasibility of the mining method; and • evaluating the design of the wash plant. The reserve risk is gauged by the amount of measured, mineable, and saleable reserves. The greater the latter amounts, the lower the risk. Secure title to the reserves plus title for any surface areas required are also of concern to the banker. Feasibility of the mining method and evaluation of the wash plant design should verify that the project can be completed according to the engineered spec-

Jan 9, 1982

By R. Adams

Zirconium is the 20th most abundant element in the Earth?s crust and it most often occurs in the form of silicate (as zircon), less often in the oxide form (as baddeleyite or caldesite). Historically, the world?s production of zircon was entirely derived from mining and processing beach sands or heavy mineral sands that were being exploited primarily for their titanium content, i.e., to generate TiO2 feedstocks that would be used for making titanium pigments and, to a lesser extent, titanium metal. Zircon was then regarded as a byproduct, with the sharply fluctuating prices typical of a commodity where the supply is essentially involuntary and not truly responsive to market demand. However, in recent years, zircon has shown considerable mining investment appeal in its own right. Projects have been planned ? and some have already come to fruition ? based mainly on the zircon potential of the deposit. Booming Chinese demand for zircon to meet the requirements of the ceramic and zirconium chemical sectors has been a major factor causing zircon prices (f.o.b. Australia) to surge from US$674/t ($611/st) at [ ] the end of 2005 to beyond US$2,400/t ($2,177/st) by the end of 2011.

Jan 1, 2012

By Luiz Antônio da Silva

Este trabalho tem como objetivo apresentar os resultados do procedimento de geração de energia elétrica adicional a geração econômica na CTE2 com gás natural, visando a redução de custo no grupo CSN.O estudo foi efetuado através da avaliação dos preços do mercado de curto prazo de energia elétrica e análise do processo de geração da planta, aos quais permitiram diagnosticar as melhores praticas e definir a melhor configuração operacional.Os resultados apresentados foram significativos para as condições de operação, o que representa redução do custo de energia elétrica para o grupo CSN e aumento da segurança operacional da planta da CTE2.

Jul 31, 2018

By A Golsby

Although much talked about, social licence to operate (SLTO) is a relatively new concept that has been deemed as one of the four biggest business risks to a mining project over the life-of-mine. There is no accepted single definition of SLTO and this author understands SLTO to be stakeholder perception of the legitimacy of a project, a company or an industry. At a specific site, and across different sites within the same organisation, SLTO ranges through different levels according to stakeholders’ degrees of acceptance in time and space. Management of SLTO is vital for the mining sector but is difficult as it is informal and intangible. Although there are no key performance indicators, there are certain indicators that enable relative measurement of the ‘level’ of the SLTO. Because of the importance of the SLTO, information management during the entire life-of-mine, from exploration to rehabilitation, becomes crucial for the continued operation of a project. This paper identifies ten basic principles for the management of information to support the SLTO.CITATION:Golsby, A, 2014. Managing information to support a social licence to operate, in Proceedings Life-of-Mine 2014 , pp 389–398 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By D. Scott Barr

The Zarafshan/Newmont Joint Venture operates the Muruntau heap leach project, located in the Kyzylkum desert of central Uzbekistan. The mine produces more than 12.4 t/a (400,000 oz/year) of gold from low-grade oxide ore stockpiles adjacent to the Muruntau open pit. It is op¬erated by the Navoi Mining and Metallurgical Combine and is one of the largest gold resources known (Fig. 1). Since commissioning in 1995, total heap leach production has exceeded 21 t (675,000 oz). The joint venture uses four-stage crushing and screening to produce a final product for heap leaching, Merrill-Crowe processing and local refining.

Jan 1, 1998

By Raphael Lemos

Durante o ano de 2008 foram observados diversos “Gap’s” no processo de lubrificação, tais como: alto consumo de graxa, lubrificação em excesso, degradação de sistemas centralizados, ausência de procedimentos, mão-de-obra sem o conhecimento adequado, entre outros. Dessa forma, o processo de lubrificação foi separado em cinco grandes grupos de atuação, sendo eles: seleção de lubrificantes, gestão do processo de lubrificação, sistemas centralizados, contaminações e vazamentos. Foram aplicadas as ferramentas do MASP (Método de análise e solução de problemas) sendo a primeira delas o "Brainstorming", nos valendo das observações realizadas no Laminador de tiras a quente nº 2. Em sequência foi definido e implantado o plano de ação. Os resultados obtidos após as ações foram: a redução do tempo de parada associada a problemas de lubrificação dos equipamentos do LTQ#2, redução média de consumo de graxa no laminador de - 6.277 kg/mês, quando comparamos a média de consumo do período de Novembro de 2010 a Outubro de 2013, frente ao consumo atual no período de Novembro de 2013 a Outubro de 2014, totalizando uma redução média de aproximadamente - 75.321 kg nos últimos 12 meses.

Aug 16, 2017

By Stephen T. Young

The construction of Phase 2 of Hong Kong Station, its retail podium and International Finance Centre Two, the tallest building in Hong Kong, will be completed in the middle of 2003. This paper describes the design and construction of the slurry wall for the Station (both Phase 1 and Phase 2) and the two commercial buildings at the Station. The slurry wall is used as the permanent earth support wall for the station box and the excavation depth ranges from 70 feet to 120 feet. Top-down construction technique was adopted to support the excavation of the station, while circular cofferdams relying on hoop stiffness were constructed to support the basement excavation of the two towers. The designed behavior of the slurry wall is also compared to the as built behavior.

Jan 1, 2003

By Jie Li

Series of carbon compounds as anode materials were prepared for super lithium ion capacitor using graphite and active carbon (AC) as raw materials. Their electrochemical properties were investigated by constant current charge-discharge test. The results showed that the compound anode had good capacitive performance as well as Li-ion battery performance. The potential of the capacitor could be as high as 3.5V vs Li/Li+ when compared with 2.5V vs Li/Li+ in the AC-AC capacitor, accordingly, the energy density increased from 21.7Wh/kg to 40.3Wh/kg. The compound anode also had excellent rate performance that as the current density increasing from 0.1A/g to 1A/g,the capacitance decreased only 1.3F/g, and good cycle performance that the capacitance holding remained 96.7% after 10 times cycles even at the highest potential of 3.5 V vs Li/Li+.

Jan 1, 2009

By Oliver Bowles

ROCK is no doubt the most abundant of all material things because the planet on which we live is made of it. All animal and vegetable organisms and the multitude of natural and manufactured products that occupy a comparatively insignificant film on the outer surface of the planet are derived from rock. Processes of Nature acting for untold centuries have transformed rock into soil, making possible the development of vegetable and annual life; and rocks have supplied the numerous raw materials, metallic and nonmetallic, wherewith the innumerable appurtenances of a complex civilization have been fabricated. As time goes on we live with increasing speed and with enlarged desires. Time and space are shortened by man's ingenuity, and products for human use must be manufactured with greater and greater celerity. It was inevitable that Nature's slow processes of rock alteration should fail to keep pace with human demands and that the variety of natural products should fall far short of the requirements of an industrial age. Man therefore supplemented these processes by attacking rock in its native bed amid using it to supply needs not otherwise satisfied.

Jan 1, 1934