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By Summers D. A.

A mining machine has been designed and fabricated to mine coal from room and pillar operations combining high pressure waterjet cutting and mechanical fragmentation. Waterjets are used to slot the coal face with an advancing plow wedge then breaking out larger coal pieces. The machine has the following advantages: - simply built around a disassembled longwall chock and gathering arm loader apron; - few moving parts which are simply and inexpensively maintained; provides immediate roof support in the face working area; - coal produced is larger, with resulting lower preparation cost; - no dust is generated; - risk of spark generation is virtually eliminated.

Jan 1, 1992

By M. Ralchenko, C. Samson, M. Svilans, C. Walsh

"Through-the-Earth (TTE) radio has been proposed as a means of emergency communications in mines. The propagation of a TTE radio signal depends chiefly on the subsurface conductivity distribution. Robust forward models of signal propagation can be computed based on a realistic conductivity estimate. These models can be used, for example, to optimize frequency, estimate signal range, identify zones of anomalously strong or weak signals, or to optimize the position of the above-ground TTE radio unit. A method was developed to determine the conductivity distribution of a mine overburden using TTE radio transmission data. At multiple locations in an underground test mine, we recorded a wideband electromagnetic signal, spanning a frequency range of approximately 500 to 8,500 Hz, transmitted from a vertical magnetic dipole at the surface. Using a finite-difference time-domain forward modeling code, a layered Earth conductivity model that accounts for topography was fitted to the observed data, which minimizes the difference between the calculated and observed attenuations for each transmitter-receiver pair, for each frequency of interest. Introduction and objectiveThrough-the-Earth (TTE) radio has been proposed for emergency underground communications. The most common type of TTE radio is based on the transmission and reception of signals by electromagnetic induction. These signals are in the extremely low to very low frequency range — in practice, between 400 and 9,000 Hz. This technology was historically developed for mine safety, although recently other applications have been suggested, such as communications in civilian infrastructure like high-rise buildings or tunnels, in the military, and even for wireless detonation and activation. In a coal mine, which is a setting of particular importance for TTE radio due to the higher risk of accidents, day-to-day communications can be done through a wired link. High-frequency line-ofsight systems, whose signals cannot penetrate rock, are also used for communications from nonfixed points. Another option is a leaky feeder system, which is a permutation of a line-ofsight system and a wired link, where a partially shielded coaxial cable allows the signal to “leak” (Delogne, 1982). In an incident such as a mine collapse or explosion, a TTE radio system can still provide a communication link, as wired systems can be severed, and line-ofsight systems cannot penetrate through collapsed portions of the mine, or to the surface (Forooshani et al., 2013; Yarkan et al., 2009)."

Jan 7, 2018

By E. Ghali, W. Zhang, G. Gabra, N. Sorour, G. Houlachi

The additives polyacrylamide, 1-Butyl-3-methylimidazolium chloride, Tetra-butylammonium bromide, Benzalkonium chloride and chitin are evaluated during zinc electrolysis from synthetic acidic sulphate electrolyte containing Mn2+ ions, in absence and in presence of 0.0055 mg dm-3 of Sb3+ ions. Galvanostatic polarization tests for 2 hours at 50 mA cm-2 and 38oC were carried out to determine the cathodic and anodic potentials, and current efficiency of the deposited zinc. Potentiodynamic polarization and cyclic voltammetry tests have also been employed to study the electrochemical behavior of each additive on the zinc deposit on aluminum electrode. Results showed that, in presence of Sb3+, adding 1 to 3 mg of 1-Butyl-3-methylimidazolium chloride increases the cell voltage by ˜0-7 mV. Current efficiency is increased by ˜4.90-6.40%; power consumption is reduced by ˜147-173 kWh t-1 by adding 1-3 mg, respectively. However, in absence of Sb3+, cell voltage is decreased by ˜7-28 mV, current efficiency is increased by ˜0.70-1.50%; power consumption is reduced by ˜41-47 kWh t-1 by adding 1-3 mg. The effect of the other additives on cell voltage, current efficiency, lead content and morphology of zinc deposit has also been examined. Surface morphology and crystallographic orientation of the deposit was studied using scanning electron microscopic (SEM) and X-ray diffraction (XRD), respectively. The content of lead in the deposit has also been measured using inductively coupled plasma spectroscopy (ICP).

Jan 1, 2015

By Ismar Antônio Sardinha

Usually outer straight steel tubes are used to blow supersonic oxygen into LD converters (BOF) to make liquid steel, although conical tubes are used too. Inner tube for oxygen blow and intermediary tube for water IN and water OUT are normally straight steel tubes. Present paper shows the influence of outer tube shape and metal used to in lance cooling and, consequently, a skull retention on lance surface. There are two parameters more important related to lance cooling: velocity of water out and the total lance cooling by addition of thermal conductivity of outer tube metal to it. For this comparison outer tubes are made of carbon steel or copper, and can be straight or conical. As related to velocity of water OUT, outer straight tubes have bigger efficiency than conical tubes. As related to total lance cooling, outer tube metal made of copper has much bigger efficiency than steel because of its thermal conductivity 7 to 12 times more depending on work temperature. The lance cooling has much bigger efficiency for the patented SKULLS3® technology with no skulls on the lance and no skulls into the mouth of LD converters (BOF).

Aug 17, 2017

By C. J. Pritchard

Controlled recirculation of ventilation air in underground metal and nonmetal mines has the potential to improve airflow and the health and safety of miners when implemented properly. Previous research by Robinson, Marks, Cecala and others concluded that the success of a district recirculation system is predicated upon an adequate supply of fresh air and the use of a reliable monitoring system for safe operation. This recent research also showed that contaminant levels will not exceed pre-recirculation levels, and that district recirculation can improve the dilution of face contaminants, especially methane gas. To illustrate the process of implementing controlled recirculation and also to promote and give guidance to mine operators in consideration of this tool to improve mine airflow, Office of Mine Safety and Health Research (OMSHR) researchers acquired baseline airflow and contaminant data from a multi-level room-and-pillar nonmetal mine and used commercial ventilation network software to simulate base case conditions and recirculation of mine air. Mine return air baseline contaminants of dust and diesel particulate matter were at lower levels than intake air, providing the potential for improved face air quality. A ventilation model implementing controlled recirculation was developed and analyzed, showing an increase in air quantity at the face, improved intake air quality, and contaminant exposure levels below those set by statutory requirements. These results, along with conclusions reached by previous researchers, provide the basis for examining the safe and effective implementation of controlled recirculation in metal and nonmetal underground mines using this mine as an example.

By B. Holen, J. R. Baregi, J. A. Organiscak, A. B. Cecala

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company’s Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system’s effectiveness in controlling airborne dusts and particulates. The booth’s dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-µm respirable size particulates under various HVAC airflow operating conditions.

Jan 1, 2015

By José Darío Sanabria Cerrón

El presente texto describe la operación de las zarandas de alta frecuencia en la etapa de molienda de las operaciones mineras del país. Durante esta etapa se consume la mayor parte de energía que debe ser aprovechada eficientemente a través de una buena clasificaciónen húmedo de la molienda en minerales para disminuir los costos operativos sobre la base productiva de la planta.

Jul 1, 2015

By R. Benito

This paper describes the development of a life-of-mine schedule (LOM) for one of the world's largest known sedimentary copper-cobalt districts located in the Katanga Province, Democratic Republic of Congo (DRC). A particular feature of the Tenke Fungurume LOM schedule is the considerable number of pits/phases for scheduling, each competing to provide the best ore available to a capacity-constrained process facility. This paper discusses the LOM scheduling objectives and constraints, data preprocessing steps such as ore binning, block aggregation and clustering analysis as a scheduling aid, the mine scheduling approach and results and conclusions. Mining Engineering, 2011, Vol. 63, No. 8, pp. 39-47. Official publication of the Society for Mining, Metallurgy and Exploration, Inc.

Jan 1, 2011

By Ricardo Rocha de Oliveira

A indústria Siderúrgica, nos dias atuais, vem enfrentando grandes desafios, no que tange à sua produção de metais. Com um cenário cada vez mais desafiador, (variação cambial, mercado externo, mão de obra local, custos de produção e logísticos, matéria-prima), as empresas do setor de Metalurgia precisam adotar soluções cada vez mais sustentáveis e com um excelente retorno a curto e médio prazo. Mesmo sob estas condições, o mercado brasileiro não para de inovar em seus processos, principalmente a indústria automobilística, onde há vários desenvolvimentos de veículos automotores que demandam o que há de mais tecnológico e moderno, tais como ligas especiais, adoção de alumínio em sua composição, aços com maior resistência mecânica, entre outros. O Segmento de Metalurgia/Siderurgia é orientado, desta forma, a realizar as mais diversas pesquisas para a otimização de processos e de produção, através de parcerias com seus fornecedores e pesquisa de matéria-prima. Com tudo isso, se verifica que é possível aplicar novas soluções, incorporando-as aos seus processos, obtendo excelentes retornos quanto a ganhos de produtividade e redução de custos de aquisição/manutenção, sem deixar de lado o fator Sustentabilidade e a prática do “Ecologicamente Correto”. Desta forma, as empresas do setor de Metalurgia/Siderurgia conseguem se destacar em seu nicho tecnológico, atendendo a demanda do mercado, apresentando excelente retorno a seus acionistas e garantindo a satisfação de seus colaboradores em todos os níveis dentro da corporação.

Oct 30, 2017

By Anna Beatriz Almeida Leandro da Costa, Erica Renata Cruz da Cunha, Dayany Karla Silva da Rocha, Mateus Nunes de Souza, Flánelson Maciel Monteiro, Bruna Pereira do Nascimento Souza

As argilas cauliníticas, popularmente conhecidas como de queima branca, possuem a coloração final dos seus produtos como principal característica. As jazidas desse tipo de argila não são encontradas com facilidade, sendo a prospecção de novos depósitos o principal desafio do setor cerâmico. Portanto, o objetivo deste trabalho é estudar as propriedades tecnológicas de uma argila caulinítica do município de Boa Saúde – RN. O trabalho foi iniciado com a coleta in loco da argila e, em seguida, seu destorroamento, cominuição e peneiramento em uma peneira ABNT 200 mesh (0,074mm). Após essa etapa, foram confeccionados trinta (30) corpos de prova utilizando uma prensa hidráulica com pressão de 21 MPa. As amostras ficaram em uma estufa por um período de 24 horas com temperatura de 100ºC para retirada da umidade. O processo de sinterização ocorreu em um forno do tipo mufla, sem atmosfera protetora, nas temperaturas de 850°C, 950°C e 1050°C, com taxa de aquecimento de 10°C/min e patamar de isoterma de 60 minutos. Em cada temperatura foram sinterizados dez (10) corpos de prova. Os ensaios tecnológicos realizados nas amostras foram os seguintes: absorção de água (AA%), retração linear (RL%), perda ao fogo (PF%), porosidade aparente (PA%) e massa específica aparente (MEA). Os resultados dos ensaios apontam que a argila estudada possui características que apontam sua utilização na fabricação de peças para os setores da cerâmica estrutural e revestimentos.

Mar 1, 2019

By O. G. Olvera

"Refractory sulfidic ores consist of materials in which gold occurs finely disseminated within metallic sulfides or forming solid solutions, with pyrite and arsenopyrite being the two sulfides most commonly associated with gold. Typical cyanide operations show poor performance and require oxidative pretreatments to increase gold recovery. Pretreatment alternatives include roasting, pre-aeration, acidic and alkaline high pressure oxidation, and bacterial oxidation. The presence of arsenic, however, introduces a serious disadvantage to the use of roasting and bacterial leaching, while high pressure oxidation involves high capital costs. This work focuses on evaluating the effect of the addition of a carbon resin as a sulfur collector on the oxidation of different arsenopyrite concentrates under atmospheric tank leaching (ATL) conditions. The addition of the resin improved the oxidation of sulfides and favored the formation of elemental sulfur over the generation of sulfate. The use of AF5 in ATL resulted in higher gold recoveries under standard cyanide carbon-in-leach and thiosulfate leaching.INTRODUCTION Refractory sulfidic ores consist of materials in which gold occurs finely disseminated within metallic sulfides or forming solid solutions, with pyrite and arsenopyrite being the two sulfides most commonly associated with gold. Gold is not readily accessible to solutions in these types of ores and typical cyanide operations show poor performance, thus making the use of oxidative pretreatments a requirement to increase gold recovery. Pretreatment alternatives include roasting, pre-aeration, acidic and alkaline high pressure oxidation, and bacterial oxidation. The presence of arsenic, however, introduces a serious disadvantage to the use of roasting and bacterial leaching, while high pressure oxidation involves high capital costs. The use of carbonaceous materials to enhance the dissolution of sulfides is not novel, and leaching additives such as coal, activated carbon and carbon powder have been considered for the improvement of bioleaching, atmospheric leaching, and pressure oxidation leaching processes. However, this type of technology has been focused mainly on the recovery of copper from copper concentrates containing chalcopyrite with less attention paid to other sulfides."

Jan 1, 2017

The Pacific Rim countries ofAustralia, New Zealand, Papua New Guinea, Indonesia, Fiji, Philippines and Solomon Islands will be reviewed from an equity investors perspective.   The following areas will be covered: Country risks Exploration spending and activity Project development Taxation Relative cost of doing business Environmental considerations Political/bureaucratic situations Capital raising Equity markets as a source of funds Developing market funds The aim of the paper will be to outline the most attractive areas for investment by equity and private funds plus documenting the changes needed in the less favourable countries if they are to attract investors.

Jan 1, 1995

By D. Chen

The experiment adopted magnetic separation-priority flotation (first to float copper,then float lead) combined technology to deal with a complex Cu,Pb ,Zn multi-metals ore which has high sulphur content, difficult to separate Cu, Pb ,Zn minerals from sulphur and separate Cu from Pb. Floatable pyrrhotite was separated through magnetic separation which could eliminate the adverse effect on the flotation followed up. And then adopting the priority flotation process to recover the Cu, Pb ,Zn from the magnetic tailings. In priority, flotation Cu, BP(a kind of ethionine ester collector ) and ethyl xanthogenate were used as the collector, LD-1 and sodium sulphite were used as the depressant.The depressants combined with humic acid sodium and lime were used for chalcopyrite ? pyrite separation to further improve the copper concentrate grade. Considering the raw ore that contain 0.32% copper, 0.54% lead and 25.54% sulfur. The copper concentrate grade is 23.61%. The lead content of copper concentrate is only 0.85% . The recovery of copper is 75.03%,and the lead concentrate grade is 54.58%, the copper content of lead concentrate is only 0.81% and the recovery of lead concentrate is 62.24%. The mineral processing indexes were excellent, finally realizing the high effective separation of Cu, Pb , Zn and pyrite. This technique provides a new approach to highly utilize complex copper-lead-zinc ore.

Sep 1, 2012

By S. Michael, T. E. Moongo

Electrowinning consumes a substantial amount of electrical energy, and owing to the ever-increasing unit cost of electrical power there is a need to improve current efficiency in the process. This research was carried out to design a continuous quality improvement framework for improving electrowinning current efficiency by applying statistical process control (SPC) on an online industrial copper electrowinning operation. A sequential mixed research methodology was applied and a statistical software package utilized for analysing data. It was concluded that metallurgical short-circuits (hotspots) had the most significant effect on current efficiency. Bringing hotspots under statistical control resulted in a 5.40% improvement in current efficiency, which is equivalent to approximately 74 t of 99.999% pure grade A copper cathode production over a period of 1.5 months.

Jan 1, 2021

By G. Y. Liu

The structure-activity relationships for four thionocarbamate collectors are discussed in this pa-per. These collector classes are alkyl alkyl thionocarbamates, allyl alkyl thionocarbamates, acyl al-kyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates. The main emphasis will be to highlight the differences between collectors and their affinities for copper and iron sulfide minerals on the basis of data on electronic-structure properties obtained by vacuum and solution density functional calculations, flotation experiments and analysis measurements. The mechanism of interaction of these collectors with sulfide minerals is also discussed with perturbation theory. The theoretical study results indicate that acyl alkyl thionocarbamates and alkoxylcarbonyl alkyl thionocarbamates have best performance in these agents as flotation collectors with improved collecting power for copper sulfide minerals and excellent selectivity against iron sulfide minerals, which are consistent with the experimental data reported in the literature.

Jan 1, 2014

"The outlook for Eastern Canada is decreased coal production and for Western Canada increased production. The market for Western coal is expected to reach 40 million tons per year in metallurgical and thermal-power markets.Technical developments in Eastern Canada include successful methane drainage experiments, modifications to the shearer-loader to improve cutting rates, mechanized mining of a tail-gate stable and mechanical stowage of level brushing. In Western Canada, the most modern equipment is used in mining, beneficiating and shipping coal. Underground hydraulic experiments were started in 1969. The importance of reclamation was recognized and plans have been made to re-vegetate disturbed areas and mine dumps.The Mining Research Centre closed the field office in Nova Scotia and is preparing to open a new field office in Calgary, Alberta."

Jan 1, 1970

By Eric Klaffenbach

Valorization of slag from metallurgical industrial processes becomes ever more important as this may help optimizing and reducing the use of natural resources such as rock and sand. In view of this objective, metallurgical processes have to be analyzed in order to modify the slag composition so that it will meet the expected requirements of potential users of these resources. This paper gives the results of a thermodynamic analysis of the flash smelting process to understand the impact of operational parameters on slag chemistry and elemental partitioning in the process. It is shown that an increase of the matte grade and temperature leads to higher deportment of Pb, Zn and As to the slag. With increasing matte grade the volatilization of these elements decreases. Furthermore, the results indicate an increasing solubility of Cu and S in slag at higher temperatures.

By Ben Habermann

"The object of the work described in this paper was to increase the understanding of the relation that capillary pressure of a rock, hydro-dynamics, and accumulation of oil in stratigraphie traps have to one an-other. The hydrodynamic oil-water tilt equation is derived by considering the two vector gradients involved: (1) buoyancy of oil in water and (2) hydraulic gradient.Recent theories show the necessity for oil to have a continuons phase in the reservoir rock in order to mi-grate; this fact applies to hydro-static as well as to hydrodynamic conditions. Hydrostatically, the displacement pressure of the rock deter-mines the amount of oil that can be trapped behind a permeability barrier. If the buoyancy of oil in water exceeds the displacement pressure, oil will migrate up-dip; an oil trap will be formed where displacement pressure is greater.In stratigraphie traps the pressure drop caused by moving water is positive when its direction is down-dip, helping accumulation; and it is negative when its direction is up-dip, forcing the oil into the tighter section of the reservoir. Theoretically, pro-vided we have data such as: (1) the displacement pressure of an up-dip permeability pinchout, (2) density difference between the oil and water in place, and (3) the direction and magnitude of the hydrodynamic gradient (if any), the possible extent of a stratigraphie oil accumulation down-dip can be predicted.To test the above theory sample cores from three wells in the Denver Basin were analyzed and the oil column that could be held under hydro-static conditions was calculated. After the hydrodynamic influence was considered, the results were compared with actual field data.The significant fact shown by this investigation is that the calculated oil column in one reservoir very closely approximates the actual extent of the oil column in a well. Also in accordance with the theory, the capillary pressure caused by the buoyancy of the oil column exceeded the measured displacement pressure on core samples from another productive field. For very tight shaly sand and questionable oil shows, the interpretation of data is very critical, as shown by experiments on core samples from a third field."

Jan 1, 1960

By F. Matanzo

This guide considers only nine of the many wire rope terminations used in the mining industry so use of the information presented for terminations not specifically addressed can be done, but with some risk. The nine terminations considered are: Flemish Loop with Steel Sleeve & Thimble, Flemish Loop with Steel Sleeve, Wedge Socket, Swaged Socket, Turn Back Loop with Aluminum Sleeve & Thimble, Thimble Splice with Four Tucks, V-Bolt Clip with Thimble, Zinc Poured Socket, and Epoxy Resin Poured Socket. The guide uses pull test data, axial fatigue test data, and data on sensitivity to poor workmanship, to rank the nine terminations with respect to these performance measures. A selection procedure is suggested and illustrated with an example. Failure data is used to identify the common modes of failure of each termination and so help the inspector direct his attention to the likely location for a failure and describe what he should be looking for. The data on which this guide is based is included so that as new data becomes available, the ranking order can be adjusted accordingly.

Jan 1, 1978

By Felipe De Lucio Pezet

El presente trabajo describe el proyecto de renovación en la metalurgia extractiva del cobre donde se buscó mejorar la ley de sus concentrados, específicamente de Cobriza. Asimismo, este permitiría obtener utilidades similares a las que globalmente obtiene el complejo minero-metalúrgico de Cuajon-Toquepala de Ilo. Finalmente, el proyecto permite obtener azufre elemental para satisfacer la demanda interna y exportación.

Jul 1, 1987