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By Gibbons S. L, Ritchie I. M, Murr D. M

Fundamental studies on the transformations of iron oxides have been carried out and related to the solution conditions in the Becher process. The results show that a number of iron oxide interconversion reactions occur in the aeration reactor with the products depending on the pH, temperature and oxidation potential of the aeration liquor. It is concluded that the lack of process control in the aeration reactor of the Becher process significantly hinders the ability to predict and produce high quality single phase iron oxides of a consistent colour.

Jan 1, 1990

By Doyle R

Underground operations commenced at Tower Colliery in late 1978 and the early prevailing mining conditions in the worked seam were considered poor as a result of high stress and geological disturbances. This suggested that outbursting activity may be a possibility. The colliery has since recorded a total of 13 individual outburst incidents, all of which have been associated with the same dyke and strike-slip fault zone. This paper depicts the geological conditions and presents the results of investigations undertaken at the time of these outbursts.

Jan 1, 1986

By Merwin RA

The recent development of rare earth permanent magnets has revolutionised the field of magnetic separation. The advent of rare earth permanent magnets in the 1980s provided a magnetic energy product an order of magnitude greater than that of conventional ferrite magnets. This has allowed the design of high-intensity magnetic circuits operating energy free and surpassing the strength and effectiveness of electromagnets. New applications and design concepts focusing on the mineral and metal processing industries have evolved. This technology also led to the development of various magnetic separators specifically designed for mineral processing applications. Applications which were not previously considered are now being applied to primary mineral upgrading and recycling and secondary recovery.

Jan 1, 1993

It has become increasingly clear in recent years that human kind has developed the capacity to alter the environment of the Earth on a global scale. The changes are often subtle. This is particularly true in the case of stratospheric ozone. Ozone is produced primarily in the stratosphere, at altitudes in excess of 20 km, initially through the action of ultraviolet sunlight dissociating molecular oxygen. According to theory as it existed up to a few years ago, ozone is removed mainly by reaction with atomic oxygen. In the unperturbed environment, this reaction proceeds both directly, and by paths catalyzed by trace quantities of nitrogen radicals. Molina and Rowland [Nature, 249, 810, 1974] pointed out that decomposition of industrial chloroflurocarbons could in-troduce an additional source of radicals to the strato-sphere. Chlorine radicals are even more efficient than nitrogen in catalyzing recombination of oxygen atoms with ozone; models suggested that we might expect reductions in the vertical column density of ozone of as much as a few per cent over the next several decades. A reduction in ozone of x¦/a, by increasing the flux of ultraviolet sunlight reaching the surface, was predicted to result in an increase of about 2x% in the number of cases of skin cancer, with other less well defined impacts on the non-human environment for life.

Jan 1, 1990

By Z Fu, E Topal, O Erten

"Mine waste rock management involving waste rock movement and placement, is a critical aspect in the planning of open pit mining operations, as the waste rock haulage cost can be the largest portion of the mine operating cost. The concept of sustainable development in the mining industry also encourages environmentally friendly waste dumps that have zero hazards to people and the surrounding environment. Therefore, a detailed waste management schedule must satisfy economic and environmental considerations. However, the available tools in the market cannot provide optimal waste dumping schedules to meet all these constraints. This paper introduces a user-friendly and automatic tool to optimise the waste dumping schedule, which minimises the haulage cost, and covers the encapsulation of reactive materials to minimise acid mine drainage problems. This tool has been developed by using a new mixed integer programming (MIP) mathematical model that considers both single-lift and multilift dumping scenarios. The application of the proposed tool on a data set collected from a gold mine shows that the multilift dumping scenario has provided a more flexible and economical waste dumping schedule than the single-lift scenario, and both scenarios satisfy environmental requirements.Citation:Fu, Z, Topal, E and Erten, O, 2016. A Modified Software Tool for Mine Waste Rock Dump Planning, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 229–242 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

IT is very difficult for a founder engaged in jobbing work, comprising all sizes and classes of castings, to appreciate that the analysis of the iron he is using cannot entirely fill the situation he desires for his varied classes of work. Neither is there any panacea in the shape of an iron mixture that will suit the whole of his floor for the day.From his own experience he generally alters his cupola charges during the cast, endeavouring to meet at the same time the requisite metal composition for the castings he is about to pour.The founder on repetition work is in a much better position to stabilise his methods, arrive at a certain pig-iron' analysis, regulate...

Jan 1, 1926

By A G McLean

This paper will first discuss the fundamental requirements for reliable discharge of backfill by gravity alone at high per cent solids. This discussion will include brief mention of the underlying principles of saturated solids flow contrasted to that of stirred tank or dilute discharge systems. Here the need to possess full knowledge of the flow properties of the stored material will be highlighted. In regard to attainment of reliable discharge it will he revealed flow from a backfill silo will only occur provided: ò the flowing material in the converging channel is yielding throughout; ò slip is occurring along the walls; ò an arched stress field is present in the vicinity of the outlet; ò the flowing backfill must be dilating to flow in response to the dilating stress field; ò sufficient dilation water is injected, in the hopper, to eliminate the formation of adverse interstitial pressure gradients; ò sufficient dilution water is injected, downstream from the hopper outlet, to generate a pumpable slurry of maximum per cent solids; ò the silo level must be sufficient to prevent the pump suction forming a rathole; ò the system must be configured and operated to generate stable discharge density; and ò the system must be configured and operated to minimise damage to the pump liners. In addition proper account must be made of the silo overflow weir and settling capacity to match plant throughput. Here opportunity will be taken to highlight the complexity of this multi-phase flow situation as well as the general yet paramount requirements for reliable solids flow. It will be shown that by proper attention to the multi-phase considerations gravity discharge of slurries as a consolidated bed with minimal water content is possible. Such high solids discharge results in greatly reduced demand for process water. In addition pumping costs are reduced as is the delay time associated with the mine drainage operation. Confirmation of successful applications will be highlighted by reference to several recent case studies. In the concluding phase mention will be made of the key yet very simple and effective operation techniques which enhance reliable Discharge.

Jan 1, 1998

By B Veera Reddy

For thick seam extraction, the Blasting Gallery (BG) method is ideal for obtaining the maximum percentage of extraction at fast rates. The continued use of this mining method is threatened by strata control and spontaneous heating problems. The strata control problems are managed, to some extent, by supporting the roof with cable bolting and roof bolts of 2.5 m length and with regular induced blasting. However, a number of BG panels were sealed off prematurely due to spontaneous heating problems, losing 1.12 million tonne of coal. The use of compressed CO2 for controlling mine fires is not uncommon in the coal mining industry, but its use is something new for controlling active spontaneous heating in a BG working panel goaf. This method was attempted at the BG I/8 panel of the Godavarikhani (GDK) 8 Incline, Singareni Collieries Company Limited (SCCL). The spontaneous heating was effectively controlled and the remaining coal in the panel was completely extracted by continuous flushing of carbon dioxide (CO2) into the goaf for 40 days. One thousand and twenty four CO2 cylinders, each of 45 kg at 80 bar pressure were flushed into the goaf at the rate of 25 to 30 cylinders (350 m3 of CO2) per day. A quantity of 35 510 tonne of coal was extracted during the period from 30 July 2002 to 7 September 2002. The main objective of this paper is to present the complete process of controlling the spontaneous heating by CO2 flushing and to report on the study of the behaviour of gases and their analysis. The unique experience of controlling the active spontaneous heating in the working Blasting Gallery I/8 panel goaf at GDK 8 Incline with CO2 flushing (till the completion of the panel) will go a long way in establishing a working procedure for handling fire/spontaneous heating problems in BG panels.

Jan 1, 2005

By G McCullough, J Bassan, d P. Knights, C T. Farrelly

By 2045, carbon-neutral mines will be economically producing products that are vital for the world’s transition to renewable energy. After overcoming significant technical challenges (and the investment of significant capital), leaders have successfully eliminated the use of diesel and other fossil fuels by introducing a wide range of new decarbonisation technologies. These leaders will be reaping the benefits of lower production costs (resulting from elimination of diesel), stable and predictable operations, and easier access to capital for their future projects. This paper describes a future scenario of how a net zero carbon and zero-entry mine could operate by taking maximum advantage of technologies in development or already proven in other industries. Some miners have been unsuccessful in their efforts to reach decarbonisation targets. Instead, they have been forced to close or offload their assets to be acquired by operators with better sustainability credentials, or, in some cases, to indigenous or community-based enterprises with vested interest in making operations viable and sustainable. Regardless of ownership structure, all successful mining operations will have fostered strong and positive community relations that bring education, health, security and economic development opportunities to the communities while respecting their traditions, land-uses and culture. As shallow, easy to mine deposits have become scarce, the majority of new mines are underground. Advancements in electric underground technology and the feasibility of ‘zero entry mining’ (with no personnel in active mining zones) has made it increasingly possible to economically operate underground mines, even at shallow depths. The newest mines have a near zero footprint on the surface, produce no harmful by-products, and are employing in-place or in situ methods of extraction that are efficient and low impact. Surface land-uses, such as agriculture and renewable energy generation, continue in the immediate vicinity of the mine, with no significant ground disturbance, community impact or environmental footprint.

Sep 1, 2024

By W Schauenburg

The increasing problems associated with the disposal of waste and the potential for use of by-products as underground filling material is a subject which is relevant not only to the coal-mining industry. The progressive scarcity of surface disposal facilities for by-products and waste has now become a problem in all sectors - not only for the mining industry. The considerable capacity offered by underground cavities which exists in various mining branches present an extremely promising potential in this context. The backfill process for coal mining developed by DMT in co-operation with Ruhrkohle AG make use of the cavities which are offered by the extraction of coal. It consists of several stages: The fine-grained by-products, such as sludge, filter cakes, fine refuse, ash and flue-gas cleaning residues are processed on the basis of specified formulations in metering, blending and pump facilities on the surface to produce pumpable pastes with precisely defined flow characteristics. On Walsum Colliery of Ruhrkohle AG up to 200 m3/h stowing paste is conveyed into the mine in pipes with diameter of 200 mm (8"). The delivery pressure of the pump operating on surface in conjunction with the hydrostatic pressure of the shaft pipe - amounting in total to as much as 25 MPa - makes it possible to convey the stowing material for a distance 12000 m underground up to the workings without any need for additional booster pumps. Via a pipe installed in the face, the paste is pressurised into the cavities in the specially fragmented rock in the mined-out zone well behind the support. Consistent use of stowage of caved-in goafs makes it possible to reduce surface settlement above the workings. Fires in the stowed rock are either smothered or completely prevented thanks to the exceptional air-tightness in the caved goaf and the cooling effects of the slurry stowage. The reduced danger of fire, the preventation of air-leakage and the positive effects on gas emission from the coal improve safety in the workings.

Jan 1, 1998

By C J. Moran

All mines face water management challenges. Adopting leading practice water management strategies can help reduce both operational and strategic risks. While many of the water issues faced by underground mines are the same as other operations, underground mining presents some unique water management challenges. In this paper we review trends in underground mining, water use and associated water issues. We then compile a structured set of strategic and operational risks that are pertinent to underground operations. The causes, threats, opportunities and measures for controlling or mitigating the risks are summarised. The risk compilation could provide an addendum for underground operations to the Australian governments leading practice water management handbook.

Mar 21, 2011

By P Williams

The Sunrise deposit is one of AustraliaÆs largest and most profitable gold deposits. It has consistently and spectacularly outperformed every resource model created. Currently over the life of the Sunrise pit there has been a 50 per cent under estimation of ounces mined. Without a solid basis for predicting the tonnes and grade or the spatial location of mineralisation, mine planning becomes problematic. Recently, through a better understanding of the mineralising processes the reconciliation of the resource model has improved to be in the order of ten per cent under on ounces mined. This paper will describe how the mine geologists at Placer Granny Smith have implemented the changes required to improve the resource model. Work began with the development of a three-dimensional lithological and structural model based on historical drilling and pit mapping. Continual updating of the geological model with grade control logging, assays and in pit face mapping, now allows for the on-going improvement of the resource model and the planning of mine development drilling.

Jan 1, 2000

By A J. Ryan

The Ernest Henry copper-gold Mineral Resource is the major asset heldby Ernest Henry Mining Pty Ltd, comprising A$6.4 billion of containedmetal. The case history presented below describing the evolution andevaluation of this resource generally observes best industry practice and is a good example of effective due diligence in the resource delineation and estimation process. Early reconciliation data from mine production confirms the accuracy and validity of the resource estimate, providing valuable assurance to the mine owners.

Jan 1, 1998

The need to schedule ore production to make maximum use of the strength gained by cem- ented fill during curing is discussed, to show how cement content and hence fill cost can be kept down for any particular operation. Results from laboratory testwork on Isa Mine fill conducted by the author while employed by Mount Isa Mines Limited form the basis of the Discussion

Jan 1, 1973

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 Coulborn W. T, Glasby G. P, Maylan M. A

Research cruises by HMNZS 'Tui' (1986) and RV 'Moana Wave' (1987) investigated the geology, geophysics and seafloor mineral resources of Manihiki Plateau in the central Pacific Ocean.Manihiki Plateau is a large (500,000 km2) mid-ocean platform that rises 3000 m above the abyssal plains of surrounding ocean basins (depth -5500 m). Its foundation evolved about 112 Ma ago by massive outpouring of basaltic lavas at a plate triple junction. The plateau is blanketed by a 900 m thick sedimentary section comprising (i) mid-Late Cretaceous volcaniclastic sandstones / siltstones grading upwards to limestones / chalks and (ii) -500 m of Tertiary nanno-foram chalks and oozes. Cores from DSDP 317 drill-site on the Manihiki High Plateau indicate that the volcaniclastic sediments contain native copper and some thin beds rich in organic carbon.

Jan 1, 1990

By D Espinoza, I Rees, J Pocoe, P Collier

P Collier, I Rees, J Pocoe and D Espinoza

Mar 22, 2022

Development of a small ore body to 137m below surface was carried out in sixteen months driving 610m of 1:5 decline.

Jan 1, 1973

By Baafi E. Y

A heuristic approach for the optimisation of the stope geometry is presented. The heuristic method uses economic model of a given deposit to search for the best combination of mining blocks that results in the maximum profit while imposing geo

Jan 1, 1998

By I A. Lamb

The Melbourne City Link Project has two tunnels, the Domain and Burnley Tunnels, which have been constructed by Transfield Obayashi Joint Venture (TOJV) under a design and construct contract. The two tunnels are located essentially under the Kings Domain, the Yarra River and, in the case of the longer Burnley Tunnel, under the inner suburb of Richmond. The Burnley Tunnel is 3.5 km long and reaches a depth of 65 m at the central Swan Street Shaft, the invert being at RL -60 m. The Domain Tunnel is 1.6 km long, with the invert reaching RL -20. The tunnels were driven, for the most part, in the siltstone and sandstone of the Silurian Age Melbourne Formation. Construction aspects of the driven tunnels as related to the engineering geology have been described by Hutchison et al (1998). The Silurian bedrock is a fractured rock aquifer that is connected to overlying alluvial aquifers. Excavation of the tunnels allowed temporary groundwater inflows which substantially de-pressurised portions of the various aquifers. This de-pressurisation provided the potential to accelerate on-going secondary consolidation rates of the Holocene Aged Coode Island Silt (CIS) and the older Quaternary Fishermens Bend Silt (FBS) deposits, in areas where these materials directly overly the aquifers. As a large portion of the urban area of South Melbourne and the old river course of the Yarra River contain extensive CIS deposits, and were within the drawdown influence of the tunnels, the management of the hydrogeological regime was very important. The permanent design of the tunnels comprised drained and undrained sections (a partially tanked design) which, along with some permanent recharge, provide long-term protection against the possibility of accelerated settlement rates. During construction TOJV implemented a comprehensive groundwater management plan to deal with issues related to the temporary drawdown of the aquifers and the temporary acceleration of settlement. This paper describes the hydrogeological regime, the effects of the tunnelling, the monitoring programs, the extensive temporary recharge system, and the consultation program that TOJV utilised to manage the hydrogeological issues.

Jan 1, 1999