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By Thiago Pinto Wandekoken

Vazamentos de água em painéis refrigerados apresentam grandes riscos operacionais e de segurança nos processos de fabricação do aço, principalmente nos Fornos Elétricos a Arco. A detecção precoce de vazamentos de água pode minimizar e/ou até eliminar grandes riscos operacionais, de segurança e patrimônio. A Tecnologia ELD, desenvolvida pela Lumar Metals, traz uma proposta inovadora de monitoramento dos painéis do FEA, que através da combinação e análise de dados coletados individualmente nos painéis refrigerados é capaz de detectar vazamentos de 0,2 l/min em até 10 segundos após sua ocorrência. A coleta de dados é realizada de forma contínua nos painéis refrigerados e transmitida via wireless. Testes em escala laboratorial foram realizados, onde os vazamentos de água foram simulados através da abertura de válvulas solenoides. Nos testes em escala industrial o sistema pôde ser avaliado em suas condições reais de operação, ficando exposto ao calor, poeira, ruídos e campos eletromagnéticos. Em todas as etapas de testes realizadas a Tecnologia ELD foi capaz de detectar os menores vazamentos de água, credenciando a tecnologia para inserção no mercado.

Jul 29, 2018

By Gökhan Çevikbilen, Ümit Karadoğan, Sevde Korkut, Berrak Teymur

This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse

Sep 29, 2022

By J. C. Potvin

Although the occurrence of deposits of titanium minerals on Kenya’s present day beaches and adjacent dune systems has been well documented, the potential for older formations to host economically viable deposits had not been recognised until recently. The Magarini sands formation in Kenya has been found to contain deposits of ilmenite, rutile and zircon in quantities and grades that have the potential to be commercially exploited. Since 1995, Tiomin Resources Inc. has explored these deposits and has identified one deposit, the Kwale project, as being able to support the development of a mine producing some 300,000 tpa ilmenite, 75,000 tpa rutile and 37,000 tpa zircon. Tiomin plans to start production by late 2002. Construction of a US$137 million operation is set to commence in the first half of 2001.

Jan 1, 2001

By Hirohide Kamada, Gustavo Scarpim

The increase in industrial demand is responsible for a consequent evolution in the process of injection of aluminum under pressure (Die Casting) to achieve requirements such as; greater geometric complexity of injected parts, larger dimensions, hard-filled cavities, thin walls, and more refined mechanical and aesthetic requirements. Thus, the industries have searched for sensible increases in pressure and injection speed, always combining the best resistance and performance of the wells submitted to the new process conditions. The need for more aggressive applications for the cavities means that there is a constant evolution of the entire production chain in the manufacture of molds, passing through several processes, among them; machining, designs with complex engineering solutions, refining in the process of heat treatments and surface treatments. Allied to these needs, high performance steels manufactured by differentiated processes with high fracture resistance, hot strength and wear must be selected. This work aims to present the main factors considered in the development of high performance molds, the engineering of materials involved, technological trends and technical engineering solutions for the different variables of the die casting process.

Nov 22, 2018

By L. J. Moore

Introduction Hydrometallurgical solvent extraction (SX) processes – featuring large quantities of combustible or flammable organic solvents - are common in the mining industry for recovering non-ferrous metals such as copper, nickel, cobalt, uranium, tungsten, iodine and lithium. Recent fire loss incidents and the widespread use of sub-grade tank farms and piping trenches, plastic piping, poor drainage, and closely spaced buildings demonstrate opportunities to improve the use of Inherent Safety (IS) in this industry. The mining industry has designed and constructed facilities with an emphasis on personnel safety, production efficiency and cost effectiveness. The use of IS to eliminate or minimize property fire exposures has not seen widespread practice. Lessons learned from the mainstream CPI have not been communicated or applied. As an example, copper SX plants have consistently used design of gravity flow as a cost and production-effective solution for transferring liquids and minerals through the process. In fact, Jergensen1 recommends to “utilize gravity to the fullest extent possible” in design of SX plants. This philosophy has been achieved by laying out SX plants with process equipment at different grade levels so that solutions can flow “downhill”. Because of the use of large quantities of flammable liquids and the potential for these liquids - if released – to flow unimpeded into other areas – gravity SX processes represent severe inherent fire consequences unless costly barriers, drainage and channeling are also provided. It appears that little thought has been given to the fire protection consequences and challenges of this design feature during the evolution of SX plants and most copper SX plants constructed today use some form of a sub-grade processing area (tank farm) and one-way gravity flow. While this layout is used to assure a cost effective operation it has resulted in significant exposures to high value production. The use of sub-grade production units is an inherently unsafe layout where flammable liquids are used and is a layout that would rarely if ever be used today by the mainstream CPI. Gravity-assist layout is only one example where copper SX plants have been designed and constructed without IS in mind. The use of combustible and frangible corrosion-resistant materials – such as glass, wood and plastic - for flammable liquid storage, processing and piping systems has significantly increased the hazards of these facilities. These materials of construction are not rigorous and allow for rapid failure and release of flammable contents during fire exposure. The use of combustible or frangible systems to handle or transport flammable liquids is not a practice seen today in the CPI.

Jan 1, 2006

The Government signalled its intention in the Economic Statement on 17 December 1987 to improve the fairness of the taxation system and to facilitate the process of economic adjustment by: removing tax concessions that benefit some taxpayers at the expense of other taxpayers,ensuring that those who can afford it shoulder their fair share of the tax burden,securing a revenue base which will provide sufficient resources to maintain effective social services,reducing artificial protection and concessions that discriminate against some sectors, and encouraging confidence through an economic environment with a medium-term orientation. The Government has clearly stated to all sectors that tax preferences will be phased out and businesses need to look inwardly to their investment policies if they are to survive in an open economy. This paper will address the effect of these Government objectives on the taxation structure for all forms of mineral exploration in New Zealand. The present tax structure will firstly be analysed, in particular setting out the tax advantages available to the industry. The effect of changes to the tax system within the recent past which relate to mineral exploration will then be examined. Finally the paper will address the question of possible future changes, particularly in the light of Government's intention to move towards a tax system which does not provide an advantage for any one sector of the economy.

Jan 1, 1988

By Francisco Belmino Romero, Walney Silva Araújo, Vitória Lima de Souza, Edilberto Rocha Silveira, Adriana de Oliveira Sousa Leite

O uso de inibidores verdes na corrosão do aço carbono SAE J403 1020 configura-se como uma alternativa econômica e ambientalmente acessível, pois, em relação aos inibidores comerciais geralmente utilizados, são de fácil obtenção, já que são adquiridos a partir de vegetais, portanto, não oferecem risco ao meio ambiente. Assim, o presente trabalho tem como objetivo avaliar o uso das folhas de aroeira como inibidor de corrosão para o aço carbono SAE J403 1020, o qual é bastante utilizado na indústria e possui baixa resistência à corrosão. A escolha da aroeira se deu devido ao fato de a planta ter origem no Brasil e abundância no Nordeste do País, principalmente no Ceará. Para análise, foram utilizados como meio corrosivo: H2SO4 0,1 M, NaCl 3,5% e NaCl (ph = 4,0); as concentrações do inibidor foram: 50, 200, 500 e 1000 ppm. Em relação aos ensaios eletroquímicos, utilizou-se: Potencial de Circuito Aberto (OCP), Espectroscopia de Impedância Eletroquímica (EIE) e Curvas de Polarização Linear (CP). Dessa forma, por meio da análise das técnicas mencionadas, conseguiu-se obter o comportamento do inibidor em relação ao material e ao meio, bem como avaliar qual o melhor meio para a utilização da aroeira como inibidor verde de corrosão.

Mar 1, 2019

By Mahyera A, Sakashita B, Ahmed U, Abou-Sayed AS

Gas in U.S. coals is primarily composed of 90 to 99 percent methane and up to 10 per- cent carbon dioxide. In composition and heat- ing value, this coal-bed gas is similar to natural gas and can be introduced directly into commercial pipelines after standard condition- ing. The high permeability cleat system in the virgin coal can be exploited in order to drain the coal gas well in advance of mining. Two premining drainage methods have been extensive- ly evaluated in the U.S.; they are 1) horizon- tal boreholes collared from within the mine, and 2) vertical drilling from the surface with fracturing. Limited-size fracture treatments are advocated in order to prevent potential roof damage and the need for added support. An engineering approach to predicting gas flow for different drainage techniques near mining locations is presented. Results can be used in design, i.e. pipeline, compressor. Coal gas drainage from a horizontal borehole and a treated (contained fracture) vertical well for a 6 foot seam have been evaluated. Based on these results, it was concluded that selection of gas drainage techniques will depend primar

Jan 1, 1982

By A. B. Campbell

The mines in the eastern part of the now active region of the Tri-State zinc district of Missouri, Kansas, and Oklahoma have unusually acid water, which during periods of moderate or no rainfall is used in the mills to replace losses from evaporation, seepage-, and tailings disposal. Its use has caused difficulties by corrosion of equipment and by interference with flotation. The growing importance of flotation, which requires good water, and the increasing troubles caused by the corrosion of the milling equipment have prompted the Mississippi Valley Experiment Station of the United States Bureau of Mines, in cooperation With the Missouri School of Mines and Metallurgy, Rolla, Mo., to investigate the action of the waters on flotation and to undertake to develop means of obviating their harmful effects. The work was under the immediate direction of W. T. Schrenk, consulting chemist, United States Bureau of Mines, and professor of chemistry Missouri School of Mines and Metallurgy, and. Will H. Coghill., supervising engineer of the ore dressing section of the United States Bureau of Mines.

Jan 1, 1932

Martha Mine is an open pit gold-silver mine, located within the township of Waihi, 150km southeast of Auckland and is operated as a joint venture between Normandy Mining Ltd. 67 %) as Manager and Otter Gold Mines Ltd. (33%). The deposit was historically mined, by underground methods from 1888 to 1952, producing 5.5 moz of gold and 30 moz of silver, from 11 mt of ore. The current operation began in 1988, producing, to June 1999 - 867,245 oz of gold and 5.5 moz of silver from 9.5 mt of ore. The licensed reserves were due to be mined out by late 2000. Consents were granted in December 1998 to allow the expansion of the operation through to 2007 accessing an additional 7.5 mt of ore at 3.4 gpt Au and 26.0 gpt Ag for 800,000 oz of gold and 6.4 moz of silver. The key elements of the expansion are: 1. Pit enlargement 2. Upgraded crushing and material handling facilities 3. Construction of a second tailings storage facility 4. Upgraded water treatment capacity 5. Increased operating capacity This paper presents an update of expansion activities to date.

Jan 1, 1999

Abrasivity and wear resistance are not intrinsic properties of materials, but rather parameters describing the interaction between the wear part and the material exerting the wearing action. Moreover, wear or, at least, that part of the wear which is due to the cumulative effect of minute scratches, is linked to the hardness disparity concept. Abrasivity, in this context, is a relative concept, pertaining to a metal-rock pair, rather than to a rock. Based on this assumption, a methodology has been developed and checked against actual cases, enabling description of the abrasiveness of a rock or the abrasion resistance of a metal through the ratio of comparable quantitative indicators. The paper describes the methods and provides examples of applications to practical cases (namely: rock cutting, excavation by means of tunnel boring machines (TBMs), rock crushing, and hydro-mill cutting).

Jan 1, 2012

"Gravity concentration remains the main separation method for fine iron ore and is used extensively for treating various minerals. Gravity concentration methods separate minerals of different specific gravity by their relative movement in response to gravity and one or more other forces, the latter often being the resistance to motion offered by a viscous fluid, such as water or air (Wills, 2006).Spirals concentrators are one of the gravity concentration equipment used for beneficiation of minerals. Spirals are typically used for processing of fine minerals (-1mm) size fraction. The main operating variables for a spiral concentrator are the feed rate, the solids concentration, the wash water addition and the position of the cutters or splitters used to separate the tailings, middling and concentrate streams (Sadeghi, Bazin & Renaud, 2014).The aim of this study is to investigate the effect of feed rate, solids concentration and wash water on grade and recovery on iron ore material. The Multotec SC20HC/7 WW spiral was used for the experimental test work. The spiral was tested at varying solids concentration and feed rate. The wash water rate was also varied to establish the best washing rate. The splitter positions were kept constant. Optimization of these variables is expected to provide optimum conditions for a good compromise between grade and recovery.INTRODUCTIONSpiral concentrators are simple low energy consuming devices that separate minerals mainly on the basis of density. Spirals are widely used in mineral processing as a method for preconcentration and have proven to be metallurgically efficient and cost effective.Spirals have a wide application, they are used in iron ore processing, coal, gold, chromites, mineral sands, glass sands, and in soil cleaning.Separation on a spiral is achieved through a combination of forces that act on particles as they move down the trough of the spiral. The main forces known to act on the particle on a spiral are the gravitational forces, centrifugal force, hydrodynamic drag, and lift and friction forces (Kapur & Meloy, 1998). Apart from the forces acting on a spiral, the properties of the slurry flowing on a spiral including, solids concentration, feed rate and wash water also plays an important role in the separation on the spiral.The relationship between separation efficiency and feed rate was shown to be linear, with a decrease in efficiency at higher flow rates. Previous work on flow profile by Holland - Batt (1990) indicated that any increase in the feed rate to a spiral results in a greater part of the additional flow volume reporting to the outside of the trough. The flow on the outside of the trough becomes energized and consequence to that the heavy particles find it hard to settle and escape this region to the inner region. This effect has a high impact on recovery of heavy minerals, since any increase in volumetric flow on the spiral is not made available for recovery in the inner region of the spiral."

Jan 1, 2015

By A. Broussaud, J. D. McKay

Benefits analysis of adaptive Expert control systems operating at plants in Africa and the United States are presented. Proper statistical tools and techniques are discussed. Technical and practical pitfalls of strategy comparison are also presented and illustrated with from published data. Advantages and disadvantages of a “Pay for Performance” approach to a project are reviewed.

Jan 1, 2001

By LEONARD S. AUSTIN

THE works of The Boleo Mining Co. are situated at Santa Rosalia, Lower California, on the opposite side of the Gulf of California from Guaymas, the, nearest railroad town. The copper deposits were discovered in 1868, and the name Boleo arose from the fact that the ore particles were agglomerated as little balls of carbonate or oxychlorides of copper. When worked on. a small scale, only ore carrying 20 to 25 per cent copper was mined; this was shipped to Europe for reduction In 1884 The Boleo Mining Co. was organized and,-the mine put in condition. Even then, due to the low price of copper, only the richer ore continued to be shipped. To operate the mine successfully the company made radical changes in the methods of development and spent money freely for construction of adequate plants for the treatment of low-grade ore. Finally, the owners of the various adjacent mining claims combined their interests and formed a joint enterprise attractive to French capital.

Jan 1, 1929

By S. E. Chetlin

In the mid-1970?s, the market value of tangible assets of S&P 500 companies far outstripped the value of intangible assets, including intellectual property (e.g., 83% tangible assets v. 17% intangible assets).1 By 2005, the picture was quite different. By that time and continuing to 2010, S&P 500 companies? market value of intangibles was about 80%, with tangible assets accounting for only 16% of market value.2 This swing highlights the importance in today?s world of understanding intellectual property rights and varying strategies and options for protecting them. This paper discusses intellectual property rights particularly patents and trade secrets, specifically: 1) types of intellectual property; 2) choosing the mode of intellectual property protection; 3) obtaining patent protection; and 4) using patents as a sword versus a shield.

Jan 1, 2012

By Chas. F. Jackson

This circular is an abstract of a manuscript-completed in August 1932, which cannot be published in its entirety due to lack of printing funds. It was originally planned to publish the manuscript as one of a series of bulletins dealing with the mining and milling of ores of the principal metals. Because of the common association of lead and zinc minerals in many ore deposits, and because a considerable proportion of the zinc produced in this country is obtained as a by-product of lead mining or vice versa, it seemed necessary to treat the mining and milling of lead and zinc ores in the same volume.

Jan 1, 1934

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

"In addition to outstanding technical sessions and networking opportunities, the SME Annual Conference and Expo offers attendees a chance to see the latest and greatest technology that the industry has to offer. The 2017 SME Annual Conference and Expo was no exception as 575 companies filled 756 booths from Feb. 19-22 in Denver, CO. The following is a look at some of the vendors that were on hand.AIL MiningThe Edge, featured by AIL Mining at the 2017 SME exhibit, is a four-flange structural liner designed to be an alternative to structural plate’s traditional lapped seams and to help mine operators build more efficiently and safely. It is ideal for creating underground structures, such as mine shafts, ventilation raises and escape ways. The Edge is available on SuperCor structural steel plate — 10 times stiffer and five times stronger than traditional steel liner plate. It facilitates curved structures, both horizontal and vertical, and eliminates the need for ring beams. It is ideal for remote sites. For added safety, structures can be assembled from the inside, and the leak-resistant structures can be dismantled and removed easily. Brackets can be attached to mine shafts or vent raises to support Alimak rails or climbers. Similarly, brackets or hangers can be attached to drifts or tunnels to support mine air, water or electrical utility services.ArcadisMining companies spent nearly $12 billion on water infrastructure worldwide in 2014, reflecting the industry’s heightened concern about environmental issues and social, regulatory and political risks.So, with an increasing focus on water reuse and recycling, mining companies must have effective water management plans that include sustainable solutions. Also, many water quality issues fall under both state and federal regulatory jurisdictions. To solve these problems, Arcadis provides comprehensive ground- and surfacewater technical support in a complex hydrogeologic setting. It can characterize the nature and extent of mine-related constituents in ground water and surface water, as well as the complex interactions between the two waters, and prepare the operational permits needed by mine and tailings facilities. As an example, Arcadis constructed a hydrogeologic and geochemical conceptual site model that improved site understanding for a molybdenum mine in the western United States that spanned several watersheds. It also provided technical support for permitting and compliance issues, allowing the mine to return to active production."

Jan 5, 2017

The Rio Tinto Iron Ore group currently estimates grade attributes for mineral resources using ordinary kriging (OK). OK produces a smoothed globally unbiased estimate, but does not capture local variability, which can have significant impact on mine planning and scheduling. The dimensions and the multivariate nature of iron ore deposits make point simulations of whole deposits impractical. With a direct block simulation method the size and speed limitations of point simulations can potentially be overcome, resulting in a viable method for capturing local variability and for providing risk measures into the mine plan and schedules. Some iron ore deposits are highly folded (post mineralisation) and require preprocessing using an unfolding algorithm to properly define the continuity parameters and directions of anisotropy before simulation can proceed. Block co-simulation proceeds in unfolded space and since mine planning require a block-model with regular block-sizes; a regular block-model is unfolded first. This paper discusses a block co-simulation approach that can be used to simulate the irregular blocks resulting from the unfolding process. A section of an iron ore deposit is used for testing the block co-simulation algorithm and the simulation results are compared against the Isatis direct block simulation method. Available blasthole data is also used to validate the behaviour of the block co-simulation algorithm.

Sep 26, 2011

By Beavis FC, Box JC

The important chemical and fluid flow phenomena in heap, dump and in situ leaching are summarised. Published, quantitative models of these processes are critically reviewed, and their potential applications outlined. Comparison between the independent predictions of one of the models and column leach test data reported by others confirms the potential. Some recent developments by the authors in the fields of fluid flow through unbroken ore and modelling of the more complex chemical systems are briefly Described.

Jan 1, 1981