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By D J. Black

The process of excavating and mining coal causes fractures in the overlying and underlying strata. The fractures provide pathways for gas released from coal seams and other gas-bearing strata to flow into the mine workings. Coal seam gas typically contains high concentrations of methane with lesser concentrations of carbon dioxide. Low concentrations of other gases such as nitrogen, hydrogen sulfide and ethane may also be present in some coal seams. In certain geological settings, particularly in close proximity to geological structures, such as faults and dykes, the concentration of gases contained in a coal seam can vary significantly between methane-rich to carbon dioxide-rich.In mine design and planning it is vital that mining engineers gather sufficient information to accurately determine the content and composition of the gas present in the coal seam and develop an understanding of changes in these parameters within the planned mining area.The longwall method of mining coal causes fracturing of the overlying and underlying strata behind the retreating longwall face. Where coal seams and other gas-bearing strata are present within the caving zone, gas will be released from the strata leading to contamination of the mine workings. If the rate of gas emission exceeds the diluting capacity of the mine ventilation, the concentration of gas in the mine may exceed the statutory limit, resulting in production delays and potentially unsafe conditions.CITATION:Black, D J, 2016. Planning effective management of gas emissions in an underground coalmine, in Proceedings Life-of-Mine 2016 Conference, pp 44–47 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Various methods and software have been trialled for simulation of Au grades at Boddington Mine. This covers in-house and public software as well as sequential and turning bands methods. The diversity of options was further expanded with comparison of point and direct block simulation. Some difficulties were encountered in incorporating high-grade restrictions. Altering parameters or software can make very significant differences and give results varying from estimations. This paper details a new simulation run with validation and tests for local calibration (or progressive correction) of the simulations to the estimations, focusing on reproduction of statistics. This approach brings to the forefront the question æwhat is the purpose of the simulations?Æ Results and some ideas for future applications at Boddington are summarised.

Sep 26, 2011

By E Hondros

Innovation and Business Skills Australia (IBSA) commissioned The Boston Consulting Group (BCG) to undertake a study into how the role of AustraliaÆs senior managers is likely to change between now and 2020 and to identify the skills and attributes that will be needed to respond to those changes. This report builds on a previous study prepared by BCG in the early 1990s for the Industry Taskforce on Leadership and Management Skills (Karpin Committee), which provided a snapshot of the Senior Manager in 2010. The following powerpoint slides summarise the 2020 Vision û The Manager of the 21st Century û outlining how the role of AustraliaÆs senior managers is likely to change between now and 2020 and to identify the skills and attributes that will be needed to respond to those changes. The presentation is summed up in the following quote from Jon Nicholson û Senior Vice President of BCG: We believe that to succeed in the years up to 2020, executives will need to master a range of hard and soft skills. Amongst other things, they will require to manage multi-generaional teams, the creativity to measure staff performance on outputs rather than inputs, and a high degree of technical and functional expertise in addition to their general management credentials. This paper is available as a PowerPoint presentation only.

Jan 1, 2006

By G McSpadden

At September 2001 the beneficiation plant at BHP Billiton Iron OreÆs Mt Whaleback mine is set to treat 9.5 million tonnes per annum (Mtpa) of iron ore, 40 per cent better than original design. This paper describes the steps, decision-making processes and innovations used to increase capacity at minimum cost. The plant was designed in 1979 to operate at 1133 t/h for 6000 hours per annum, treating 6.8 Mtpa. Sufficient suitable contact ore was unavailable and feed was finer than planned. The plant was designed with minimum surge capacity between multiple process units. It had never reached design capacity. In 1993 a study by Fluor Daniel to treat increased tonnage resulted in modifications to improve plant operations. Efforts to expand production by increasing reliability did not achieve the desired capacity. NJ Morrow (Pty) Ltd (NJM) conducted a technical audit in 1996 with process evaluation by Mineral Processors. Replacement of operator interface and PLC logic in 1997 made plant operation and diagnosis easier. Involving operators in logic development enhanced their plant knowledge. Fluor Daniel Simulation developed a simulation model of the process. Mineral Processors and NJM reviewed the model findings, recommended metallurgical improvements and developed preliminary designs and costs. BHP Engineering produced a detailed design with a cost estimate of $A34 million. After analysis and revision of the design, a $A10.4 million upgrade to 8.5 Mtpa was carried out. Detailed modifications to the process units, particularly the HM drum plant, allowed significantly higher capacities and improved metallurgical performance. The target capacity was achieved in June 2001. Further modifications are progressing to treat lower-grade ores.

Jan 1, 2002

By S Mitra, D O’Dea, N Barrett, T Honeyands, E Copland

This work describes a novel mapping technique that allows the direct overlay of calculated local phase equilibria on micrographs of the physical system. The technique demonstrated integrates FactSage™, ver 8.2 (by Thermfact Ltd. and GTT-Technologies) phase equilibria calculations with mapped compositions determined by Scanning Electron Microscope – Energy Dispersive X-ray Spectroscopy (SEM-EDS) to visually express calculated properties while preserving the spatial information of the sample. The developed methodology is used to analyse interrupted blast furnace softening and melting tests containing mixed burdens of lump and sinter. Tests are interrupted at 1300C and cooled to room temperature for analysis. Phases present at room temperature are analysed to infer the liquid fraction and phases present at high temperature. Analysis of the interface regions between the dissimilar burdens allows insights to be gained into the interaction mechanism. During the transition from solid to liquid, migration and interaction of liquid oxide across the interfaces of the dissimilar burdens has been observed and demonstrated to impact softening and melting performance. Specifically, interaction of the oxides generated by lump (primarily FeO, SiO2 and Al2O3) and sinter (primarily FeO, CaO, SiO2, Al2O3 and MgO) are analysed, and the occurrence of a range of new mineral phases such as merwinite, melilite, olivine and bredigite observed.

Jun 19, 2024

By Z-Y Pi, B Zhang, S Wen

"The paper introduces the structure and work processes of outside auger hollow claw tipped mechanical sampler for coal. Twenty sets of claw tipped sampler performance tests show that: The design of inner hollow cylinder-type (?180 mm) can ensure to take a coal sample with nominal top size of 60 mm. Built-in self-cleaning piston pusher ensures no adherence and blocking of the sample. The operation practices show that the mechanical sampler can operate in order for taking coal sample with up to 16 per cent of total moisture. Claw closing design can avoid sample leaking or spilling during the claw lifting and ensure the integrity of primary increment. Ultrasonic positioning device makes the sampler capture the materials no less than 10 cm from the bottom of the wagons, basically meeting the requirement taking full depth of the sample. The precision and bias test indicates that the moisture and ash have no relative bias under the sampling process; the sampling precision is in accordance with the requirement in IS013909.At present, the spiral mechanical sampler is widely used for coal sampling but there are many limitations during application, for example: It is difficult to capture a large size sample, so the size range of a coal sample taken is limited. There is easy adhering or blocking for high moisture coal, which will result in the mixture of different increments, wear of sampler and the difficulties for cleaning and maintenance of sampler. It is difficult to capture the coal sample at lower than 30 cm from the bottom of the wagons, in order to avoid damage of the vehicle. It is possible for coal sample loss and spilling during the sampler lifting, due to the unsealed sampler.For the outside auger hollow claw tipped mechanical sampler designed for solving the above problems, the opening distance of the claw is the opening size of the sampler and makes the size range of the coal sample to be taken wide. During sampling, the two pieces of claws open and the sampler rotates vertically downward to capture an adequate coal sample after reaching the specific point. Then the two pieces of claws close tight automatically to ensure there is no coal leaking or spilling. The inner pusher of the sampler will prevent from the adherence and blocking of the coal sample effectively.CITATION:Zhang, B, Pi, Z-Y and Wen, S, 2012. Outside auger hollow claw tipped mechanical sampler for coal, in Proceedings Sampling 2012, pp 41-44 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 21, 2012

By H Han, X Wang, T Li, D Duan

"In this paper, the reduction and separation behaviour of iron and slag in carbon composite iron ore pellets has been investigated experimentally using an electric resistance furnace simulating a rotary hearth furnace process. The factors that affect the formation of iron nuggets, such as temperature, holding time, molecular ratio of C/O and basicity, are discussed. Results show that the reduction of iron ore, carburisation of reduced iron and the composition and quantity of slag are very important for producing iron nuggets. Through optimisation of process parameters, iron nuggets can be formed below 1300¦C when holding time is 20 minutes, C/O is 0.7 and basicity less than 0.5. This study provides a theoretical and technical basis for iron nugget production.CITATION:Duan, D, Han, H, Wang, X and Li, T, 2013. Iron nugget production technology in rotary hearth furnace process at lower temperature, in Proceedings Iron Ore 2013, pp 363-368 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

By B Chapman, B Gaida, L Drowley

The 372 MW Ulu Jelai Hydroelectric Project is a peaking power scheme located in the Cameron Highlands, Malaysia. The main features of the project include an 84 m high roller compacted concrete dam; two weirs which divert flows from adjacent catchments via transfer tunnels into the main reservoir; an underground power waterway; and an underground power station complex comprising three large caverns with connecting tunnels approximately 240 m below surface level. The project includes approximately 25 km of tunnels excavated in fresh granite rock mass with some distinct shear zones of weaker material. The majority of the tunnels are being excavated using drill and blast, with the two transfer tunnels being excavated with a tunnel boring machine (TBM).This paper focuses on the design and construction of the Telanok underground power station complex and also some aspects of the design for the headrace tunnel. Topics covered include geological site investigations including in situ measurements of rock stresses; development of a geological model and parameters for rock support design; three-dimensional modelling to assess interactions between the caverns to optimise rock support; design of a rock anchored crane beam; construction of the caverns and design of the unlined headrace tunnel taking into account hydraulic jacking and operational pressure fluctuations.CITATION:Drowley, L, Gaida, B and Chapman, B, 2014. Design and construction of large caverns in granite – Ulu Jelai Hydroelectric Project, Malaysia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By F P. van der Meer, E Lessing, E Matthies

High pressure grinding rolls (HPGR) technology is growing to be a common comminution tool in iron ore processing. The technology finds a wide acceptance and presents specific benefits in coarse ore grinding and closed-circuit grinding in preparation of ball mill feed, right down to the other end of the particle size spectrum for iron ore pellet feed preparation.A growing number of minerals processing plants are facing higher operating costs and difficulties due to a scarcity of process water, which in some cases is a result of more stringent environmental constraints. In addition, many new iron ore deposits are located in more arid regions of the world. These challenges have led to operators taking a new look at dry processing of iron ores.The use of dry crushing and classification technology in cement production from blast furnace slag, clinker material or limestone feed stocks indicates that the technology may be applied in minerals processing. In addition, dry processing provides the possibility of generating a final product from finely disseminated and inter-grown ores at sizes near or well below 100 µm, as may be required for beneficiation techniques such as in fine magnetic separation, flotation or magnetic flocculation.Dry grinding by HPGR has a number of specific features, challenges and opportunities, including balancing power input, moisture content requirements and classification efficiency in the process design. HPGR parameters and the latest HPGR design and sizing capabilities indicate considerable potential benefits from this dry processing technology.This paper highlights some of the specific issues that play a role in dry HPGR application, with respect to energy and materials balances. Examples of dry HPGR practices and process studies in iron ore mineral processing are discussed.CITATION:van der Meer, F P, Lessing, E and Matthies, E, 2015. Iron ore final grinding by high pressure grinding rolls and air classification, in Proceedings Iron Ore 2015, pp 197–204 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The MIMDAS geophysical data acquisition system developed and tested by the former MIM Exploration Pty Ltd (MIMEX) is now commercially available worldwide through Geophysical Resources and Services Pty Ltd (GRS). The system implements several new features in its design that give it significant advantages over conventional systems and allows for new approaches to electrical exploration. In particular, the achievable signal to noise levels permit exploration to depths once thought beyond the range of electrical exploration. The flexible multi-channel configuration lends itself to truly 3D surveys in the style of modern seismic techniques. Each of these aspects is illustrated with a number of case histories from both Australia and South America.

Jan 1, 2004

Virtual reality (VR) simulators represent a powerful tool for training humans to perform tasks which are otherwise expensive or dangerous to duplicate in the real world. The idea is not new. Flight simulators have been used for decades to train pilots for both commercial and military aviation. These systems have advanced to a point that they are integral to both the design and the operation of modern aircraft (Adams, Klowden and Hannaford, 2001; Mastaglio and Callahan, 1995). This technology has been successfully extended and utilised in the mining industry in a range of successful applications (Bise, 1997; Denby and Schofield, 1999a; Schofield, 2005; Henning et al, 2002; Kaiser, Vasak and Suorineni, 2005). There are a number of lessons that can be learned from other industries that have successfully utilised virtual technology for a number of years. Specific rules of thumb regarding the specification, development, application and operation of these simulators can be garnered from other industrial training systems and examined in a minerals industry context (Tromp and Schofield, 2004; Schofield, 2006). This paper intends to discuss some of these generic rules in the context of a number of recently developed virtual reality mining applications.

Jan 1, 2008

By B Wentzinger

This paper presents the results of state parameter estimates in an active coal boiler ash storage facility using the most recent methods currently in use for cone penetrometer interpretation. State parameters estimates are also compared with the critical yield stress ratio approach, which is proposed as an additional liquefaction potential screening method. Recommendations are provided regarding additional in situ tests and laboratory tests that may be undertaken to improve the state parameter assessment and data produced for use in subsequent stability or liquefaction studies.

Jul 1, 2021

By Nethery JE

At the Red Dome and Mungana deposits in north Queensland, Australia, it is proposed that mineralisation and alteration developed as a "telescoped" overprinting continuum, ranging in style from hypothermal to epithermal, reflecting the major changes that developed in the regional setting over the period circa 325 - 290Ma. Regional assessment suggests that this also applies to many other precious and base metal deposits within a 401an length of the host Siluro-Devonian Chillagoe Formation. A ten stage paragenetic sequence of structural preparation, multi phase intrusion and associated mineralisation, alteration and brecciation is postulated for the Chillagoe district.

Jan 1, 1995

By Krokhmai VS, Sayko OP

The paper summarises the theoretical and experimental studies which led to the development of new industrial equipment designed to recover liberated gold from placer gravity concentrates. The new technology is based on environmentally clean magnetic methods, which avoids use of mercury in the production process and obtains higher gold recoveries compared to the amalgamation technique, and which can reach 98.6 - 99.5 per cent. The complex of equipment thus developed is now commercially used at nine Russian gold mining operations. Six more such complexes are due to come on stream in 1993, some of them outside the CIS. The new technology appears to hold much promise for the recovery of precious stones (diamonds, rubies etc) semi-precious stones (pyropes, chrysolites etc) and also artificial diamonds, for which case there are encouraging laboratory results.

Jan 1, 1993

By J Cook, S Pike, D Pridmore

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The application of high-resolution seismic reflection to map structure and/or mineralisation in hard rock environments has progressed significantly in the last decade. Improvements in equipment, field practice, processing and understanding has seen the seismic reflection technique emerge as a cost-effective tool for high-resolution three-dimensional structural and lithology mapping to depths far greater and with superior accuracy than other more conventional geophysical techniques.This paper outlines results and preliminary interpretation of 2D and 3D seismic reflection surveys aimed at defining fault zones and locations for quartz load development in favourable host lithologies at the Cracow low-sulfidation epithermal gold system in Queensland, Australia.As this is possibly the first time that high-resolution seismic reflection data has been used to define the structurally-controlled location of low-sulfidation epithermal gold mineralisation, an important aspect of this work was the derisking or due diligence steps taken prior to commissioning the full 3D surveys at each site. This included full wave sonic logging, vertical seismic profiling and trial 2D lines. Interpretation of the 2D profiles and the drilling of interpreted structure provided the confidence to proceed with the full 3D survey.The advantage of collecting 3D data extends beyond ensuring that the received reflections are located correctly in 3D space. The final 3D data cube can potentially map the entire fault network, thus highlighting flexures and changes in orientation of the structures both vertically and along strike, which is an important aspect in the deposition of gold and for direct targeting.CITATION:Smith, R, Cook, J, Pike, S and Pridmore, D, 2015. Application of high-resolution seismic reflection surveys to exploration for blind vein systems at the Cracow low-sulfidation epithermal field, in Proceedings PACRIM 2015 Congress, pp 77–84 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R Morrison, P Owen

Particle breakage is an essential part of mineral processing. The aim is to reduce run of mine mineral ore to an optimal size for liberating target minerals and for subsequent recovery by separation processes such as flotation. This size reduction is typically accomplished in a series of stages in a grinding circuit tailored to the properties of the particular mine ore. Commonly this involves two or more classes of equipment starting with crushers, followed by SAG mills and then sometimes ball mills. Occasionally, high pressure grinding rolls or other novel devices are substituted. Broadly, energy consumption increases and energy efficiency decreases with the fineness of the material produced by each piece of equipment. For many operations, up to 50 or 60 per cent of total greenhouse gas emissions from a plant arise from the operation of the comminution circuit with the majority produced by the finest grinding parts, such as the SAG and ball mills. Wear of mill liners and grinding media also add to greenhouse gas emissions generated by their manufacture. The need for continual cost reduction and increasing regulatory and social pressure relating to greenhouse emissions create a strong need for improvements in comminution energy efficiency. Traditional experimental and modelling approaches are not well placed to create the required insights into comminution fundamentals or facilitate radical step changes in performance. This paper discusses the role that advanced modelling (based on coupled DEM and CFD) can play in improving the energy efficiency and performance of existing mainstream grinding equipment and in the development of new ones with radically superior performance. Achieving this goal will also require an improved understanding of ore breakage and methods to include sufficiently realistic breakage models within the DEM models. Developmental issues for the modelling and the critical need for validation of the advanced model features are highlighted.

Jan 1, 2004

By M W. Chen, I Canbulat, S Saydam, C G. Zhang

The height of fracturing (HoF) measures the propagation distance of continuous fracturing from the mining horizon and is also termed the height of cracking (Hebblewhite, 2020; Khanal et al, 2019) or hydrologically the height of groundwater drainage (Tammetta, 2013). In longwall practice, HoF is an important predictive indicator for assessing the dewatering effect of panel extraction on the shallow aquifer and surface flows. The HoF determination is basically dependent on field measurement works, typically using surface extensometer, borehole televiewer imaging, piezometer monitoring, packer testing, borehole breakout logging, and isotopic tracer monitoring (Brown and Walsh, 2022; Corbett, 2022; Hebblewhite, 2020; Holla and Armstrong, 1986; Mills and O’Grady, 1998; Walsh et al, 2022a, 2022b). These methods or tools have been widely applied to observe rock fracturing and groundwater responses to longwalls at Australian coalmines, for example, Dendrobium Mine (Brown and Walsh, 2022; Walsh et al, 2022b), Appin Mine (Walsh et al, 2022a), and Springvale Mine (Corbett, 2022). In Chinese mines, borehole televiewer imaging and packer testing are more frequently used due to convenient instrumentation, quick testing, and not requiring long-term maintenance of the instrumentation boreholes. The HoF determination also involves further raw data interpretations, for which specialist software for data extraction and quantitative criteria for bounding the fracture transition and termination are necessary. By combining the measured fracture distribution and longwall parameters regarding panel geometry and geological settings, several HoF models have been developed for conceptualising the understanding of strata depressurisation and providing mine engineers fast calculation tools for HoF prediction. The Mackie model considered the height of fracturing as the upper bound of fractured zone and revealed that within the fractured zone there are highly connected fractures and accordingly porosity enhancement and groundwater depressurisation, where the fracture network can be less transmissive from the mining horizon up (Hebblewhite, 2020). The fractured zone shares similar fracturing regime but different heights in varying models: HoF is 30 to 58 times of the mining height (t) based on Australian, Soviet and UK experience (Kendorski, 1993, 2006), and 21 to 33 t according to the field measurements in NSW Central Coast, Australia (Galvin, 2016). Some Australian longwall mines adopt Ditton model (Ditton and Merrick, 2014) (Equations 1.1 and 1.2 in Table 1) sourcing from NSW coalfield experience for HoF prediction, while Liu model (Liu, 1981) (Equations 2.1 to 2.4 in Table 1) developed from 27 coalmines in China is frequently used by Chinese coalmines.

Nov 29, 2022

By Durucan S

The southern Attiki peninsula is a very interesting area from an environmental point of view. The port and the city of Lavrio is situated at the east coast of the peninsula with about 10 000 inhabitants and there are also a few villages in the vicinity. The south-eastern part of the peninsula hosts the famous Lavrio mines which exploited the silver bearing orebodies of the area for more than 25 centuries. As a result, soils around the city of Lavrio are polluted with high heavy metal loads. The area is also of archaeological interest, as there are well preserved remnants of ancient mining and processing plants and archaeological sites. Soil samples collected from an area of approximately 120 km2 around Lavrio were analysed for their metal contents and the spatial distribution of the concentrations of ten selected elements were estimated from these data sets. The spatial data analysis and transformation capabilities of Geographic Information Systems, combined with extensive mining and geological data, helped the authors to identify the extent and causes of metal pollution around Lavrio.

Jan 1, 1995

Inefficient conveyors suffer carryback, leading to the build-up of materials on idlers, and other expensive components. They spill and leak material at loading zones and transfer points, causing accumulations that can damage the belt, wear moving components, and increase both cleanup labor and maintenance expense. They wander or mistrack, spilling material and en- dangering personnel and conveyor components, including the belt itself. And through these inefficiencies, they multiply an operation's hidden costs-the dollars lost because of missed production, of increased downtime, of the expense for the replacement of prematurely worn or damaged equipment. In this paper, the author will examine the importance of belt conveyors to mines and process plants He will trace the state-of-the-art in systems for cleaning belts, and controlling the release of fugitive material from conveyor transfer points, by exploring the roots of the problems, and demonstrating solutions that have been proven to be effective. Included in these systems to improve material handling are transfer point stabilization and sealing systems, dual belt cleaning systems, and belt training idlers.

Jan 1, 1991

By J Mauk

Water-rock reactions such as pyrite oxidation and calcite dissolution strongly influence the pH of pit lakes that develop in open-cast mines after mine closure. The Martha Mine, located in world-class epithermal Au-Ag deposit at the southern end of the Coromandel Peninsula, New Zealand, is scheduled to close in 2007, after which the pit excavation will be rehabilitated into a recreational lake; the first pit lake in New Zealand. Mineral distribution maps from XRD results of 130 andesite samples identify regions that could produce or consume acidity in the future pit lake. Maps show pyrite, calcite, adularia, albite, illite and chlorite distribution in the wall rocks. These data identify five alteration mineral associations: potassic, propylitic, weathered, oxidised and weakly-altered. Pyrite occurs in potassic, propylitic and weathered associations, whereas calcite is restricted to propylitic association in the northeast wall. Subaerial, epilimnion, and hypolimnion exposure zones describe the physical and chemical weathering processes that are likely to occur in regions of pit wall, and the potential effects on lake water chemistry. The pH of epilimnion water will depend on the relative abundance of pyrite and calcite in the propylitic association in the northeast wall, whereas hypolimnion pH will depend upon the frequency of whole-lake circulation events that distribute dissolved oxygen to deep lake layer. In mines with diverse alteration associations, mineral distribution maps are an essential precursor for accurately estimating water-rock reactions in pit lake environments. Data may be directly incorporated into a quantitative geochemical model of future pit lake water chemistry.

Jan 1, 2002