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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 Paul S. Korinko, Simona E. Hunyadi Murph

To address a radiological contamination event, a materials and process project was initiated. During the course of this project, processes and materials were developed that successfully captured zinc vapors physically and chemically, respectively. However, the physical traps were placed in an undesirable area and it was determined that the chemically captured zinc reactions was reversible. Consequently, advanced nanomaterials are being developed to capture zinc vapors. The current state of the art of the science and engineering of these materials and their efficacy for zinc capture and retention is discussed in this paper.

Jan 1, 2015

By S. P. Sandoval

In 2002 the Freeport-McMoRan Technology Center undertook research to develop a lower-cost alternative to guar for cathode smoothing in copper electrowinning. The work was conducted at the Technology Center?s SXEW Test Facility located in Morenci, Arizona. Bench-scale copper electrowinning cells were designed and implemented to screen a number of potential polymers for cathode smoothing. These included modified polysaccharide polymers that were nonionic, cationic, and anionic in nature.

Jan 1, 2010

By P. Schilizzi, A. Jarosz, M. Karmis

This paper is concerned with subsidence prediction methods and in particular with two techniques, one based on profile functions and the other on influence functions. Profile function methods provide a tool for a fast calculation of subsidence on a line across a mine panel. Influence function methods, on the other hand, allow for a more detailed calculation of ground movements, in any mode and at any depth, on a grid or at any specific point. In more detail, the hyperbolic tangent profile function, as developed by VPI&SU from field data pertaining to the eastern U.S. coalfields, and an influence function method currently being adapted for the same region, are presented and discussed. The applicability, advantages and limitations of these techniques are examined and comparisons are presented with field measurements. Computer software developed for the application of these prediction methods, for two widely used personal computer systems, are also discussed and a number of examples are presented demonstrating the potential of such programs.

Jan 1, 1986

By Matt Schuett

Antamina Mine Facts • Surface Water Design Principles • Drainage Areas • SEDCAD Modeling • Impacted Runoff Collection • Clean Runoff Collection • System Flexibility • Outfall Construction

May 1, 2004

By A T. Yuniar, C A. Brannon, N D. Pascoe, H H. Firdausi

This paper describes the key components of the Grasberg Block Cave (GBC) mine design and the development and construction status of the mine. Drawpoint production from GBC will be initiated in 2018 following the closure of the Grasberg open pit. Full production of 160 000 t/d is planned for 2024, which will make it a 20-year time period between initial access development in 2004 and full production.Diluted ore reserves are about 1 Bt at a grade of 1.0 per cent Cu and 0.78 g/t Au. The mine plans some 2400 drawpoints on a 20 m × 30 m drawbell spacing in a 700 000 m2 footprint using the El Teniente layout. The drawpoint opening sequence includes five production blocks, the first two of which are scheduled to be undercut simultaneously in 2018. Ore is transported using diesel-powered load-haul-dumps to a series of orepasses and then delivered via loading chutes to a rail haulage system, which delivers the ore to a three gyratory crusher complex. Crushed ore is transported to the mill stockpiles via dual inclined conveyors.Development and construction of the substantial fixed facilities are now well underway. Primary access for personnel and materials is via the 6 km Ali Boediardjo (AB) adits. A service shaft will hoist personnel and materials from the AB adits level to the various operating levels. Shaft commissioning is scheduled for late 2015. The rail haulage system installation and construction is in progress and is due to be commissioned in 2017, which is timed to coincide with the commissioning of the ore handling system. Ventilation is provided through a series of large intake and exhaust drifts, and two of the four main fans have been commissioned. A 1600 L/s pumping system will manage drainage from the mine.Other key facilities include separate shops for rail and rubber-tired equipment, warehousing, a powder magazine, a main control centre and an underground concrete batch plant.CITATION:Brannon, C A, Firdausi, H H, Pascoe, N D and Yuniar, A T, 2016. Development and construction update of the Grasberg block cave mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 625–634 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By F. A. Myzenkov

The technology developed by the authors uses new methods for raw material smelting in electric furnaces, a new autogenous method and apparatus for subliming smelting for antimony trioxide production and separation of antimony and gold. Concentrate produced from the ore deposits in Yakutia has the following average contents of main constituents, % by weight: 29.4 Sb, 1.2 Fe, 13.1 S, 40.0 SiO2, 0.2 As, 2.6 CaO and 45 g/t of Au. Unlike the technology used abroad a new autogenous method makes it possible to increase considerably specific capacity and reduce gold losses with antimony trioxide by several times. At the same time mineralogical composition of trioxide has improved considerably ? it has mainly a cubic base with prevalence of senarmontite. The content of a main component (Sb2O3) in the final product has increased from 99.0% up to 99.6% which means better quality and makes it suitable for use in special technologies. Despite a lower antimony content of the concentrate (29.4% as compared with over 33% as common in the world practice), an antimony recovery of 85.3% into a commercial-grade product has been achieved, as well as a gold recovery of 96.65% into a gold-antimony alloy. The technology for processing gold-antimony materials developed and introduced at the Ryaztsvetmet plant is unique in the world with respect to gold recoveries.

Jan 1, 2006

By J. E. Quinn, S. Wolstencrof, K. H. Soldenhoff

Ion Exchange (IX) using Strong Base Anion Exchange (SBA) resins is conventionally used to purify uranium from sulfuric acid pregnant leach solutions (PLS), particularly when uranium grades are relatively low. However, the presence of chloride in the PLS interferes negatively with conventional SBA based IX processes, by reducing the uranium loading on the resin. Chloride can be present in the PLS due to the use of saline bore or seawater in leaching, or chloride containing leach/IX reagents. ANSTO has been examining strategies to combat this problem for several years. ANSTO previously reported that a recently developed high-capacity SBA resin was capable of extracting uranium efficiently from saline leach liquors produced at Boss Resources’ Honeymoon in-situ recovery mine in South Australia. The resin was tested successfully in a 2017 Field Leach Trial carried out onsite in the existing wellfield area. While the piloting was extremely promising, the elution was more challenging, with eluate tenors limited to 2 g/L U3O8 using NaCl. This is due to the resin’s strong affinity for the uranium complex, which makes it difficult to elute efficiently by standard methods. In this paper, we describe a novel elution process developed for strong base resins that significantly improves upon conventional methods. The process, developed by ANSTO, is based upon conversion of the extracted uranyl sulfate species to uranyl carbonate, followed by elution with sodium chloride. The loading and elution process was demonstrated in continuous locked-cycle piloting conducted at ANSTO in 2019. The results were excellent, with eluate tenors of 8–9 g/L U3O8 achieved from Honeymoon PLS containing 50 mg/L U3O8, with very little transfer of impurities. In subsequent test work, the eluate was shown to be amenable to uranium peroxide precipitation. The results represent a huge step forward for the purification of uranium from saline leach liquors.

Jan 1, 2020

By S. Hadley, M. Placha, M. Mishra, V. Choudhry

Under a DOE-funded project, four advanced flotation technologies (the Jameson cell, the Outokumpu HG Tank Cell, an open column and a packed column) were evaluated at the benchscale to identify the technology or combination of technologies that best improved fine coal recovery and reduced processing costs. The results indicated that two-stage application of the Jameson and packed column cells provided the optimal performance. Subsequently, proof-of-concept scale testing was conducted at the Cyprus Emerald Coal Preparation Plant. The results confirmed that levelized production costs were lower using two-stage cleaning with the Jameson cell followed by the packed column.

Jan 1, 1999

By A. Hotta

Reduction of CO2 emissions is the key driving force behind the development and implementation of new solutions for energy production. One solution is circulating fluidized bed (CFB) combustion technology combined with a high-efficiency once-through water-steam cycle. Foster Wheeler's CFB technology is today commercially available in capacities up to 800 MWe with ultra-supercritical steam parameters. Simultaneously, the Flexi-Burn® CFB technology is being developed to provide capability of flexible operation in air firing and oxy-combustion for carbon capture. CFB technology can offer an attractive solution for the reduction of CO2 emissions, owing to advantages such as fuel flexibility and low emissions that the air-fired CFB technology offers today. Pilot test facilities provide information about the performance of CFB oxy-combustion technology, and the acquired knowledge is being incorporated in boiler modelling and design tools. One of the European R&D initiatives on carbon capture and storage (CCS) is the Technological Centre for CO2 Capture and Transport, which is supported by the Spanish Government through the Fundación Ciudad de la Energía (CIUDEN). CIUDEN is a research and development institution created by the Spanish administration in 2006 and fully conceived for collaborative research in CO2 capture, transportation, and storage. The Technology Development Centre for CO2 Capture and Transport comprises two technologies on oxy-combustion: pulverized coal (PC) and circulating fluidized bed (CFB). This paper will focus on the design and main characteristics of the 30 megawatt-hour thermal capacity (MWth) oxy-CFB boiler. Foster Wheeler is the technology provider of the Flexi-Burn CFB unit, for which commissioning has been completed in the first quarter of 2011. The CFB unit design allows operation either under conven¬tional combustion with air or under oxy-fuel conditions. The size of this experimental boiler is sufficient to allow the scaling of the results to commercial units. In this way, multiple fuels and operating conditions can be tested economically. The results will validate the design of a future 330 MWe supercritical Oxy-Combustion Power Station (OXY-CFB-300 Compostilla Project) intended to demonstrate the CCS technology at commercial scale. The Compostilla OXY-CFB-300 Project is one of the six CCS demonstration projects funded under the European Energy Programme for Recovery (EEPR) of the EU. The project is based on a future 330 MWe CFB supercritical oxy-combustion plant, with CO2 storage in a deep geological formation. The first phase of the project, granted by the EEPR programme and led by the Spanish utility ENDESA, includes all studies and characterization work needed on CO2 capture, transport, and storage, as well the costs, financing, and regulatory and permitting required, prior to the final investment decision for the construction phase of the plant by the end of 2012.

Jan 1, 2012

By R Edwards

Greater efficiency of capture of minus 6 mm to fine micron size particles of free gold is achieved with the Knelson Concentrator. The development, principles of operation and recent innovations relating to this enhanced gravity concentrating device are described by the inventor, followed by a description of application and consequent economic benefits in low grade alluvial gold deposits by a large scale user of Knelson Concentrators in the Northern Territory of Australia.

Jan 1, 1990

By Edwards R

Greater efficiency of capture of minus 6 mm to fine micron size particles of free gold is achieved with the Knelson Concentrator. The development, principles of operation and recent innovations relating to this enhanced gravity concentrating device are described by the inventor, followed by a description of application and consequent economic benefits in low grade alluvial gold deposits by a large scale user of Knelson Concentrators in the Northern Territory of Australia.

Jan 1, 1990

By J. Shawn Peterson, David S. Yantek, Adam K. Smith

Occupational noise-induced hearing loss continues to be one of the most pervasive health problems in the mining industry, despite over 25 years of regulation. One of the loudest pieces of equipment used in underground mining is the continuous mining machine. Noise sample data collected by the Mine Safety and Health Administration indicate that 42% of noise overexposures between 2000 and 2005 involved continuous mining machine operators. Previously conducted field and laboratory tests have determined that the continuous mining machine conveyor system is a dominant noise source. Loud impacts occur as the conveyor chain flight bars, used to move the mined aggregate, traverse their path from the top to the underside of the conveyor deck. Various noise control treatments have been applied to abate noise caused by the conveyor system. A durable polyurethane coating has been developed for the conveyor flight bars, resulting in a time-weighted average reduction of 3 dB(A) for an eight-hour work shift. In an attempt to further reduce continuous mining machine operator overexposures, a similar urethane coating has been applied to the tail roller component of the conveyor system. Laboratory results showed a 2 dB(A) reduction in sound power levels, but the component failed during underground durability testing. An outer steel sleeve has been added to the urethane coating of the tail roller to enhance wear resistance during mining. The urethane jacketed tail roller is the latest effort, combined with previous noise treatments, to bring the continuous mining machine into compliance with federal noise regulations.

By AMIR EHSAN KIANFAR, Moritz Ziegler, TOBIAS HARTMANN, ELISABETH CLAUSEN

Accurate positioning information is a central step in the process of increasing automation and digitalization in the mining industry. Underground mine environments are prime examples for GNSS-denied environments that pose several additional challenges for the employed indoor positioning system (IPS). This work presents an ultra-wideband (UWB)–based system specifically tailored for underground mine environments. Initially, the UWB technology is reviewed and basic concepts of IPS are explained. Both software and hardware are described in detail, including positioning algorithms, electrical circuitry, and the mining-compatible enclosure. Finally, the results from field tests in an underground mine are presented and positioning performance and the influence of dilution of precision (DOP) on positioning results are empirically evaluated. The results show that the localization errors are mostly below 1 m. Individual zones of high localization errors are suspected to be caused by noise interference. Significant DOP influence due to the mining drift geometry can be confirmed. The system shows promising localization results for different mining applications, while influences negatively impacting the accuracy are presented as items for future research.

Jul 7, 2023

By Fredrik Sarvell, Leo-Ville Miettinen, Veli-Matti Uotinen

"Abstract The continued concentration of building activities in cramped areas of city centres means more underground construction and facilities. Demand to minimize execution time and any kind of disturbance to business, general traffic, people and nearby technical structures is increasing. To answer these challenges foundation business has to develop schedule-wise and technically reliable deep excavation and foundation solutions in vulnerable surroundings and challenging soil conditions.Drilled pipe pile wall – RD-pile wall – is a combination of Ruukki drilled steel pipe piles and interlocking sections. Individual RD piles, typical diameters between 219 mm to 610 mm, are connected to each other with interlocks welded to the piles on the automated welding line at the workshop. The matching dimensions of the drilling system and interlocking sections allow the installation of RD piles through stones and boulders and even into the bedrock, if necessary, in a single operation. Installation is done by a down-the-hole hammer (DTH) using the centric drilling system and oversized ring bits or a drilling system consisting of a pilot bit and reamer wings.RD-pile walls have been used as permanent and temporary retaining walls for different kinds of demanding excavations and structures, such as bridge foundation, as quay wall and as sealing structure in rehabilitation of an existing dam. Rigidity and watertightness of the lower end of the RDpile wall is being researched as well as fire design issues examined. One of the most fascinating RDpile wall solution is to utilize the wall as a permanent underground basement wall. Reliable and rigid connection to bedrock decreases the bending moment and deflection of the wall and good fire resistance in addition to large variety of pile dimensions and steel grades gives possibilities to design and execute a cost-efficient basement wall and foundations without temporary retaining wall works. 1. IntroductionIn northern Scandinavian soil conditions, installation of sheet pile walls, or even secant pile walls, is often problematic due to the existence of hard and large boulders in the overburden, and especially when the retaining wall structure should penetrate to or into the hard bedrock. On the other hand, an efficient and reliable piling technique suitable for the demanding soil conditions described above, percussion drilling, has been developed since the 1960’s, and especially from the mid-1990’s, when the concentric drilling method with the ring bit and pilot was introduced. A new retaining wall application, the RD pile wall was developed by combining that drilling method with the widely used retaining wall solution based on steel pipe piles and welded interlocks (a pipe pile wall normally installed with vibratory or impact hammers)."

Jan 1, 2014

By P. Choquet, F. Miller

"The development and testing of a simple low-cost gauge for measurement of tension in a cable bolt grouted in a borehole are presented. Its principle is based on a resistance wire which is wound on a 70 cm length into the spiral grooves of the wire strand cable bolt. Readings are then taken by a robust automatic data logger with a several day autonomy or by a portable readout. In order to have a complete profile of tension along the cable bolt, a number of tension gauges can be installed along its length.This paper provides a description of the development and laboratory calibration of the tension gauge and addresses the two modes of loading for a cable bolt in a rock mass, namely pure tension and shearing at a joint location.In the second part of the paper, four field tests in underground and open pit mines are reported. The first test was used to substantially modify both the gauge and the readout unit principles while the other tests which are still on-going show a very satisfactory behaviour of the modified version of the tension gauge. IntroductionCable-bolting is often used as ground support in Canadian mines for a variety of applications. In underground mines, cable bolts can be installed vertically at the back of cut and fill stopes or in an inclined fashion in the walls of large open stopes. Alternatively, cable bolts at Mines Gaspe (Noranda Inc.) are used in a fan-shaped pattern from a drill drift to stabilize the inclined roof in 25 m wide open stapes. This new application oriented our research efforts toward the design of a novel instrumentation to monitor the efficiency of most commonly used 5/8-inch cable bolts."

Jan 1, 1988

By Gerald L. Stolarczyk

Safe and efficient coal extraction requires advanced radar subsystems that can be mounted on cutting drums of coal cutting machines. A look-ahead radar (LAR) must solve the radio geophysics problem of transmitting an electromagnetic (EM) wave through at least 20 feet (6.1 meters) of coal to an air- or water-filled void. The reflected EM wave must be processed in the radar electronics to determine the physical distance to the void. Horizon sensing enables selective cutting near the undulating sedimentary rock boundaries of the coal bed to address coal quality and ground control issues. Both sensors require subsystems for dynamic electric power generation, real-time measurement of drum rotation angle, detection of reflected EM waves, and processing to determine distance through coal and RF modem transmission of measured data to the mining machine. This paper describes the development of the subsystems and field test results.

Jan 1, 2006

By S M. W Rajaratnam, P Varma, T L. Sletten

Mining employees undertaking shift work are at considerable risk of experiencing sleep disturbances and circadian rhythm disruptions. In the complex, high-risk environment of mining, these sleep and circadian disruptions lead to adverse impacts on employee health, alertness and safety. Evidence-based tools that effectively target improvements in sleep health amongst shift workers are needed. Variability in work hours and individual differences in the response to shift work mean that a ‘one-size-fits-all’ solution is often insufficient in complex work environments. Currently no interventions provide tailored support for shift workers based on their rosters, personal commitments and sleep habits. Existing technologies, such as smartphone applications and watches, allow sleep monitoring, but their strategies are targeted towards night sleepers, which does not translate to shift work contexts. To address this, our team has developed an innovative digital tool that implements biomathematical models to provide automated, personalised sleep and circadian intervention strategies to optimise sleep, alertness and performance during shift work. The tool uses mathematical models of sleep and alertness regulation that provide physiologically optimal times for an individual to sleep when experiencing circadian disruption. This program of work included co-designed development of a world-first app with shift workers and the examination of the preliminary efficacy of the intervention for improving sleep, alertness and performance.

Apr 16, 2024

By E. Munnik

The Chambishi Metals Cobalt Plant in Zambia has recently installed a novel oxidation/precipitation pressure leach process as part of the COSAC (CObalt from Slag And Copper as by-product) Project. Aniron-cobalt-copper alloy, produced by the carbothermic reduction of slag, is atomized and pumped to the COSAC Leach Plant, where cobalt and copper are recovered as dissolved sulphate salts, andiron is rejected primarily as hematite. Cobalt and copper are subsequently recovered as cathode metal in the existing Chambish ioperation by conventional electrowinning. This paper examines the challenges faced during the design and subsequent successful commissioning of the COSAC Leach Plant. The challenges discussed include alloy handling, autoclave design, autoclave cooler design, residue liquor recovery and the water balance design. Keywords: Chambishi, Avmin, COSAC, Zambia, Copperbelt, cobalt, copper, alloy handling, pressure leach, autoclaves, cooling, filtration.

Jan 1, 2003

By A van Jaarsveld

Environmentally-friendly, safe and cost-effective technology for stope drilling has successfully been introduced at TauTona mine. It has enabled the problem of inadequate compressed air pressure and its downgrading impact on production capability to be overcome. The paper traces the development process which culminated in the conversion of the entire stoping operation at TauTona to electric drilling. Background work which took place at other mines is also described. Statistics of performance improvements are provided. 1. Introduction Holman?s Silver series and the Seco S215 were drills that had a measurable impact on the South African gold mining industry. It is too soon to say whether Hilti will join those great names. However, there is no doubt that the introduction of electric drills into the harsh and unforgiving world of deep level gold mining is a significant development. History has shown that being the first to enter a new technology is no guarantee of long-term success. The pain and suffering which accompany the birth of anything new can deplete the energy of the innovator while at the same time creating opportunities for competitors to leapfrog him. In addition to commitment and enthusiasm, the innovator must therefore also possess, or have access to stamina and resourcefulness to overcome the unexpected difficulties which will inevitably arise. All of these were needed for the Hilti project.

Jan 1, 2008