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By Frederick B. Kuhnow

Harmonic energetic delamination a building is being considered for demolition at a formerly known atomic power lab. The building is within a containment structure under a negative pressure, so that no radioactive material is leaked out to the environment. A new approach was developed to make this work possible.

Feb 1, 2020

By E Coffison, M Gibbs, C Bennett

The sustainable management of surface water associated with coal mining and coal seam gas projects is a considerable factor affecting the global competitiveness of these resource companies operating in Australia. Management of surface water can be costly, but effective water management and hence environmental stewardship enhances corporate social responsibility and the social license to operate. The surface water issues for the two industries are comparable, yet there is currently a lack of alignment between how Queensland, where the majority of AustraliaÆs coal seam gas projects are located, manages and regulates water on coal mine projects and coal seam gas projects.This paper provides a high level comparison of Queensland legislation and highlights the lack of alignment of this legislation regarding surface water management in these two industries. Through a case study, it looks at the surface water management process at a coal mine site based on the current legislation and principals of surface water management. QueenslandÆs lack of alignment in legislation regarding surface water management in these industries is understandable given the different development paths and time scales of the two industries. The coal mining industry has developed over a long period of time and the legislation has progressed in parallel, whereas, the coal seam gas industry is relatively new in Australia and the legislation has had to advance quickly. The lack of alignment between management of surface water for the two industries creates confusion among stakeholders and this adds complexity and additional transaction costs during the exploration, permitting and operational phases of projects, including landowners who may be affected.CITATION:Bennett, C, Coffison, E and Gibbs, M, 2013. Lack of alignment between regulation of surface water management in coal mining and coal seam gas, in Proceedings Water in Mining 2013 , pp 157-162 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By David N. Montgomery

The characteristics of a closed cavity acoustic coupler were measured. Various configurations were investigated to determine their feasibility for use in a portable audio dosimeter calibrator.

Jan 1, 1976

Jan 1, 1884

By Yashar Pourrahimian, Roberto Noriega

Truck fleet dispatching plays a crucial role in reducing operational costs and fulfilling operational targets in open-pit mining operations and is subject to large uncertainty arising from the operating cycles of trucks and loading equipment. This paper proposes a reinforcement learning-based truck dispatching system. Reinforcement learning is a machine learning area that deals with learning an optimal sequential decision-making strategy in an uncertain environment. An open-pit load-and-haul simulation is developed that also captures the truck movements and interactions in the shared road network, and a Neural Network is successfully trained to suggest truck dispatching decisions in a real-time manner.

Jun 25, 2023

By W. E. Lockley

This paper will attempt to answer a number of questions which are important to the safe and continued operation of an electric power system. 1. WHY should electrical protective devices be tested? 2. WHAT devices should be tested ? 3. WHEN should they be tested ? 4. HOW should they be tested? 5. WHO should test them ?

Jan 1, 1977

By Xiaowei Du, Xitao Wang, Xuekun Shang

The deformation behaviors under both tensile and compressive forces and microstructure evolutions of cast SA508-4N steel were investigated at elevated temperatures. True stress-strain data were obtained from hot deformation experiments performed on a Gleeble-3500 thermal-simulator under different temperatures (750-1200C) and strain rates (0.001-10 s-1). The reduction of area decreases as a function of temperature from 750C to 900C and then increases. At 1200C, the reduction of area reaches more than 99% with the strain rates of 0.5 s-1 and 1.0 s-1. The dynamic recrystallization under compressive stress occurs at 800C under low strain rate and a complete dynamic recrystallization can be observed when the temperature reaches above 1100C. A “two-stage” flow stress constitutive model concerned with dynamic recovery and dynamic recrystallization was established based on the true stress-strain data. This model shows good agreement with experiment results. Moreover, we developed a dynamic recrystallized grain size model to describe the average grain size after complete dynamic recrystallization.

Oct 1, 2019

By Ananda Moreira Vaz Ourique de Avila

High and intermediate temperature fuel cells (FC) are power generators characterized by high efficiency and their use in cogeneration systems. The single fuel cells are connected in series by the use of interconnects to form a fuel cell stack. Ferritic stainless steels have been used in the making of high and intermediate temperature operation solid oxide fuel cells interconnects. However, at high temperatures, on the order of 700-8500C, these steels can present significant oxidation and degradation processes, promoting increased electrical resistivity and corrosion losses that result in contamination of the electrodes and reducing the performance and the useful life of the FC. Intensive R&D activities have been made to minimize these problems and the use of composite coatings on metallic substrate has been considered. This paper evaluates the use of coatings of copper and nickel, with particles of La2O3, Y2O3, CeO2, LaCrO3 and doped chromites applied on ferritic stainless steels AISI 430, AISI 441 and Crofer22APU produced by electrodeposition. The produced samples were evaluated by microscopy techniques, gravimetric analysis and by electrothermal characterization. The most significant results were obtained with chromites coatings (LaCrO3 pure, mono- and multiple-doped) showing the combination of the best features of metal coatings, substrates and ceramic particles with semiconductor properties.

Aug 7, 2018

By K. V. Raj

"Air inversion is a meteorological phenomenon generally occurs during winter times. Release of pollutants below the inversion height in an open-pit mine during periods of weak winds and consequently weak vertical mixing may result in very high concentrations of primary and secondary pollutants, causing serious consequences for health and safety of miners. Mine operations cease if the concentration of NOx or CO exceeds the threshold limit value (TLV) of the pollutants. Artificial ventilation is required to dilute the pollutants to an extent that mine workers can safely resume work. Studies of the turbulence parameters suggest that effective ventilation of the pit and removal of pollutants can be accomplished if a large enough mixing length in the open pit can be created. Turbulent mixing by eddies of different length scales under an inversion layer is product of wind shear, thermal gradient and buoyancy. The main result of turbulence is mixing of the atmospheric profile and transport of momentum. Computational fluid dynamics (CFD) Simulation results of a novel mitigation approach using cloud cover will be presented in this paper. INTRODUCTION In extreme climatic conditions, deep open-pit mines tend to trap pollutants at the pit bottom due to air inversions. Keeping open pits adequately ventilated is a considerable challenge for the mining community. Mine operators in cold regions are very familiar with this problem, the severity of which can be judged from Figures 1 and 2. The top portion of the figures show clear sky and snow covered benches. The brown haze, containing various contaminants accumulated over time in the pit under the air inversion, can be seen in the bottom portion of the figures. Several Arctic or subarctic mines have reported air inversions. Even Rio Tinto’s Bingham Canyon pit in Utah has reported local air inversions from time to time [1].Mitigation of pollutants in deep open-pit mines in the Arctic is a challenging task. Release of pollutants below the inversion height in an open-pit mine during periods of weak winds and consequently weak vertical mixing may result in very high concentrations of primary and secondary pollutants, causing serious consequences for human health. Mine operations cease if the concentration of any one of the pollutants (NOx or CO) exceeds the TLV. Sustained cessation of a mine operation has serious economic consequences. For continued mining operation, the levels of pollutants must be below the TLVs. If no significant synoptic meteorological situation changes during an inversion, a warm air mass sits over the cold air mass within the open pit. Artificial ventilation is required to dilute the pollutants to an extent that mine workers can safely resume work. Some of the early approaches in artificially ventilating open pits were attempted in the USSR. Most of the studies by Soviet researchers suggested the use of turbojets and turbo-propeller engines, airscrews, axial pit fans, and meteotrons [2, 3]. However, the majority of these studies were only theoretical in nature, with no evidence of an approach that really worked in practice."

Jan 1, 2017

By Lívia Maria Sant’Ana do Prado

Neste trabalho foi avaliado um método alternativo de redução dos óxidos de cobre, a técnica de redução assistida por plasma de hidrogênio em reator de plasma pulsado de corrente continua (cc). O plasma de hidrogênio apresenta como possibilidade a produção de espécies de alto poder redutor, derivadas da molécula de H2 [1], além de produzir majoritariamente, como produto da reação, o vapor de água que não é prejudicial ao meio ambiente [2]. A pesquisa se limita ao estudo da influência da pressão do processo de redução a plasma sobre a redução de pós de óxido de cobre (I) (Cu2O). Os experimentos de redução foram realizados em um reator a plasma pulsado DC, sob fluxos de hidrogênio de 300cm3/min, temperatura de 300°C, tempo de 60 minutos e pressões variáveis de 267, 534, 800 e 1068 Pa. Determinou-se a eficiência da redução através de um balanço de massa e foram feitas as seguintes análises nos produtos da redução: difração de raios-X, microscopia eletrônica de varredura e EDS. Os maiores valores de frações de redução foram obtidos a 800Pa, o que pode estar associado à formação de uma bainha catódica que envolve por completo e de maneira uniforme a superfície das camadas de pó.

Aug 8, 2018

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 G. S. Hume

Dr. K. A. Clark: No one will doubt the statement of fact that, during drilling operations through the bituminous sand beds in the Mildred-Ruth Lakes area, the core-barrel was found to contain bitumen with minor amounts of sand instead of bituminous sand. But many will doubt the interpretation of this fact as meaning that beds of bitumen occur interstratified with the bituminous sand beds. They will prefer to hold faith in the laws of physics, which deny that sand will float on oil or that fluid under pressure will not flow away through a permeable medium, until it is proved that the appearance of the oil in the core-barrel was not due to circumstances surrounding the drilling of the bituminous sand beds. The implication of the interpretation that sand is floating on oil is clear and it is unacceptable. Bituminous sand is unconsolidated sand more' or less saturated with a viscous oil. It is as difficult to conceive of bituminous sand lying on top of a body of the viscous oil as it is to conceive of unconsolidated sand more or less saturated with water lying on top of a body of water. The only difference between the two concepts is that the oil is viscous whereas the water is fluid. Oil-soaked sand placed on viscous oil would, when released, sink through the oil slowly, whereas water-soaked sand would sink through the water quickly.

Jan 1, 1947

By Eddy Dénommé, Deni Villeneuve

"Niobec mine, a producer of pyrochlore concentrates since 1976, became a producer of ferroniobium in 1994 and achieved accreditation to the ISO 9002 standard in 1995. The goal of ISO 9002 is to ensure that the products supplied to clients regularly meet their specifications, through explicit work standards and procedures throughout the production process, from deposit appraisal to ferroniobium production.A key element of ISO 9002 implementation at Niobec consists of the quality control procedures applied to the raw materials: the ore fed to the mill and the pyrochlore concentrate fed to the reduction plant. These controls extend from exploration, deposit appraisal, mine planning and reserves estimation, mining, mineral processing and, finally, ferroniobium production. The implementation of ISO 9002 has allowed more efficient control of the quality of the final product sold to clients. It requires interactive team work, the role of the geologist being to relate all information pertaining to raw material and product quality to the geological framework of the deposits."

Jan 1, 1997

By Adam Bedell, Jack Raymer, Brad Crenshaw

Tunnel contracts often include provisions for pre-excavation probing and grouting for areas ahead of the tunnel heading. If grouting triggers are met, tunneling stops, and grouting is performed. There is substantial variation within the underground industry on what criteria are applied to the grout verification hole that is drilled post-grouting and before excavation resumes. The criteria for determination of the effectiveness should be dependent on the geology and local hydrogeologic conditions. The purpose of this paper is to present specific criteria that can be used by a practitioner to determine whether tunneling can resume or if additional grouting is required.

Dec 1, 2022

By Fabio Loyola

La planta de adsorción de carbón de Pampa Larga (CIC_PL) es la principal planta que contribuye a la producción de Yanacocha. Las pérdidas de oro ocurren a partir de la solución gastada que va a la planta de tratamiento de agua y luego se descarga al medio ambiente. Se identificaron dos oportunidades de mejora para lograr un mejor desempeño de la planta. Una oportunidad está relacionada con mejorar la adsorción de oro sobre el carbón en una solución con alto contenido de cobre. La otra oportunidad está relacionada con mejorar el control operativo de la planta de carbón, al usar el manual corporativo de carbón activado, como también aumentar la actividad del carbón y optimizar la cantidad de carbón en los tanques del circuito de adsorción.

Sep 29, 2023

By Christopher Newman, David Newman

The ability to assess, address, and predict mining-induced stress distribution is paramount in maintaining a safe and efficient underground operation as coal mines continue to develop at deeper depths and in more geologically complex reserves. This is especially true for longwall mining operations given their limited flexibility in panel layout and orientation. This paper focuses on ground behaviors and conditions observed at two deep-cover, steeply dipping longwall mining operations in Utah’s Unita coal basin. This region is susceptible to coal pillar bump/bounce events as a result of high depth of cover, high-extraction mining, and the close proximity of a thick massive stiff sandstone stratum to active mineworks. The successful prediction of mining-induced coal bump events for Mine A and Mine B operating in the Unita basin has prompted mine management to develop a rock mechanics testing database for reserve calculations. The database is applicable to mine planning as well as the development of multiple numerical models to proactively identify and address adverse ground conditions using input parameters calibrated to site-specific behaviors and conditions. For both Mine A and Mine B, the most critical question relates to longwall development and recovery for “extreme” deep-cover longwall panels at overburden depths greater than 600 m. This paper highlights the impact of high-stress concentrations associated with deep-cover longwall mining as well as the methods applied to mitigate stress impacts on miner safety and longwall production.

Jul 1, 2023

By A Hughes, S G. Rosin

This paper presents the design and construction approach adopted for the widening and stabilisation of the existing decline tunnel forming part of the Scenic Railway Upgrade project at Katoomba in the Blue Mountains of New South Wales (NSW), Australia. The overall upgrade project included new trains and track, rebuilding of the top and bottom station and installation of a new winch and control system. All the works were undertaken over an eight-month period between August 2012 and April 2013 as part of a $30 M upgrade of the railway.The railway is the steepest cable-driven line in the world at a maximum of 52° extending over 350 m and descending from the escarpment into the Jamison Valley. The track was built in the 1880s for coal haulage and is recognised as a remarkable engineering achievement for its time. The tunnel section extends for about 120 m at the start of the decline and is about 3.5 m wide and 3.5 m high. The tunnel was excavated principally within medium to high strength Banks Wall sandstone and given that the widening only involved about 200 mm of trimming of the crown and sidewall this aspect of the work was not a critical support issue, except at the upslope portal. The tunnel crown however is entirely intersected by a major near vertical shear zone which presented significant challenges for the tunnel stabilisation works.Three-dimensional laser survey scanning was used for definition of the tunnel clearance envelope for the widening, and also to subdivide the tunnel into various geotechnical sections to assist in support design. Specifically oriented rock bolts extending beyond the shear zone into stable rock were used together with mesh, shotcrete and extensive strip drains and flushing points for drainage of the shear zone.Unique aspects of this project were included into the specifications and work methods. This included construction of a mobile working platform for tunnel works, the use of dry shotcrete application, difficult access for rock bolting and limiting vibration during the tunnel trimming works due to the risks associated with crown instability. The works also took into consideration particular safety constraints/work exclusion areas to address the risk of detachment of rock which could mobilise downslope to the track area below. This was required because other works were in progress such as micro-piling and bottom platform works which were being undertaken concurrently with the tunnel work.CITATION:Rosin, S G and Hughes, A, 2014. Scenic Railway Tunnel upgrade in the Blue Mountains, New South Wales – an approach to design and construction, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 607–618 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Erwin Riyanto, Roy William, Karl Llewellyn

The Deep Mill Level Zone (DMLZ) mine is currently one of the deepest block cave mines in the world. The rock mass is heavily veined with little to no joints and faults are usually healed cohesive structures leading to difficult cave mining conditions. The caving process is improved if the rock mass contains fractures with sufficient density that it will cave by gravity as undercutting progresses. Hydraulic fracturing (HF) has been used to create fractures around the cave to improve mining. A seismic monitoring system has been used in DMLZ since the start of mining. Therefore, the seismic activities before, during and after HF can be monitored. Shear wave splitting is a process used to study the impacts of HF on the rock mass. This process involves the measurement of travel times from splitting shear waves after seismic events and using this to define the anisotropy within the rock mass and subsequently fracture density. This paper sets out the methodology for carrying out the interpretation of the shear wave splitting process using seismic data from the fracked cave crown and abutments along with an overview of the benefits to cave mining as result.

Apr 26, 2022

By Charles de Abreu Martins

Os efeitos da temperatura de austenitização, taxa de resfriamento e adições de Cr ou Mo nas transformações de fases de um aço 0,12C-1,70Mn-0,2V, utilizando dilatometria, foi investigado. Os diagramas em resfriamento contínuo de sete aços foram elaborados e as microestruturas foram identificadas utilizando microscopias ótica e eletrônica de varredura. Em temperaturas de austenitização mais elevadas, taxas de resfriamento mais altas e maiores adições de elementos de liga (Cr ou Mo), houve uma elevação significativa da temperabilidade e queda na temperatura Ar3. Uma comparação entre os efeitos do Cr e o Mo também foi realizada, mostrando um efeito mais efetivo do Mo. Foi observada redução na temperatura Ms com o decréscimo da taxa de resfriamento. Não foi observada variação significativa de Ms com o aumento da temperatura de austenitização ou adição de elementos de liga.

Aug 8, 2018

By David Fernando de Carvalho

Este estudo de caso foi solicitado por uma grande mineradora brasileira à Chemtech Engenharia, com o objetivo de avaliar um projeto de um Transportador de Correia de Longa Distância na fase conceitual, onde se buscava a otimização do consumo energético, mínimo investimento financeiro inicial e redução dos custos operacionais. O resultado deste estudo de caso foi usado como diretriz no projeto básico do equipamento, além de ser usado como referência para outros projetos similares.

Sep 25, 2017