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By E S. Weiss, S P. Harteis

The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) has conducted full-scale explosion experiments, to evaluate the strength characteristics of various seal designs, used for safely isolating worked-out areas in underground coal mines. Large-scale explosion tests conducted within the multiple entry section of PRLÆs Lake Lynn Experimental Mine (LLEM) is currently the only accepted test method used by the Mine Safety and Health Administration (MSHA), for deeming a seal design suitable for use in American mines. These explosion tests are labour intensive, expensive to conduct, and can interfere with other critical underground safety and health research programs conducted by NIOSH. The PRL has developed an alternative seal evaluation method, based on a hydrostatic pressure loading concept, that can facilitate the in situ testing of seals in an operating mine. Two chambers within LLEM and one within PRLÆs Safety Research Coal Mine (SRCM) were used for hydrostatic pressure loading various seal designs. The results from these chamber tests compare favourably with those from the large-scale explosion tests in the multiple entries. In addition to testing seal designs at the required 20 psi static pressure level, the chamber test approach also allows for the determination of the sealÆs ultimate design strength. Size-scaling relationships for predicting the strength of seal designs as a function of entry size are also presented.

Jan 1, 2005

By A N. Parry, G van Wyk

"Sensor based automatic ore sorting technologies are used in the minerals industries to efficiently remove waste and submarginal grade material from crushed and screened run-of-mine (ROM) ore, producing a coarse (typically >10 mm) upgraded preconcentrate at an early stage in the mineral processing circuit. This avoids additional energy intensive downstream processing of this rejected component of the ROM feed, leading to lower unit operating costs and reduced tailings disposal volumes.Test work on bulk low-grade gold ore stockpile samples from Central Norseman Gold Proprietary Limited has been conducted, indicating high gold recoveries as well as high material rejection rates. A financial model, based on these results, evaluates grade sensitivity and identifies a minimum stockpile grade for adequate financial returns. The base case modelling estimates that the ex-stockpile grade (including the fines bypassed fraction) can be more than doubled through ore sorting and that the project will be highly viable with strong cash flow generation at stockpile grades as low as 0.7 g/t gold. The modelling will enable the company to benchmark ore sorting options against stockpile reclaim and screening operations currently employed. Citation:Parry, A N and van Wyk, G, 2016. Upgrading Low-grade Gold Ore Stockpiles by Preconcentration Using Ore Sorting - an Assessment of the Economic Impact and Viability, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 179–190 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By B A. Webler, P Su, P C. Pistorius

Advanced high-strength steels (AHSS) typically have much higher aluminium concentrations (by an order of magnitude or more) than conventional low-carbon aluminium-killed steels. The resulting lower oxygen activity at the steel-slag interface changes the kinetics and thermodynamics of steelslag reactions. Previous work showed that the rapid transformation of alumina inclusions to spinel inclusions, and spinel to periclase, occurs because of the relatively high concentration of dissolved magnesium. In this paper, experimental results on nitrogen removal by ladle slag are compared with predictions based on the available thermodynamic databases. As in previous work, the kinetics was modelled by assuming mass transfer control, with steel or slag mass transfer limiting. The results show that significant removal of nitrogen by steel-slag reaction is possible.

Aug 21, 2024

By Pak DL

Over the last decade computers have become an essential element in assessing the economic feasibility of mining new mineral deposits and in assisting a variety of related support functions. A broad overview is given of the many technical application areas where computers are contributing to the mining industry with reference to work being done on the evaluation of drill hole information, mineral inventory modelling, ore reserve estimation, financial analysis, process simulation, process control, workshop job scheduling, PERT applications, and com- puter aided drafting. In all these areas the computer has greatly reduced the manual effort involved in looking at alternatives. It has had a significant effect in eliminating delays in revising calculations, or rescheduling activities to incorporate new data or cater for changing conditions, while at the same time providing more accurate and prompt information for the management decision making Process.

Jan 1, 1980

By P C. J Blackney, I M. Glacken

Spotted Quoll is a massive sulfide nickel deposit located in the Forrestania greenstone belt in the Archaean Yilgarn block in Western Australia. Discovered in October 2007, mining has progressed from open pit to underground and currently uses longhole open stoping with paste fill as the primary stoping method. Immediately prior to 2019, the Mineral Resource estimate (MRE) was defined by a single grade domain of nickel greater than or equal to 0.8 per cent, irrespective of the host lithology, a legacy of the original ore wireframe being built using explicit methods. While a number of obvious structural offsets were honoured in this nickel grade domain, only one modelled fault was used to undertake domaining of arsenic. From 2019 onwards, implicit modelling in Leapfrog Geo™ was used to construct a mine-scale geological model, which triggered the definition of a high-grade core of massive/matrix nickel sulfides surrounded by a low-grade halo of stringer/disseminated nickel sulfides in the surrounding rock. As part of the evolution of the geological model and with the aid of Seequent Central™ to allow collaboration between site-based mine geologists, Perth-based resource geologists and Melbourne-based consultants, a detailed review of the structural mapping was carried out as additional information from underground development became available. This allowed numerous faults and shears to be identified – particularly in the lower half of the mine. These were used to define further structural domains and to refine the understanding of the nickel and arsenic grade distributions in the mineralised envelope. The increased definition to the domains provided by the geological model resulted in a significant improvement in the accuracy of the Mineral Resource estimate, as measured by reconciliation using voids of the mined stopes determined from the cavity monitoring survey (CMS).

Mar 22, 2022

Thank you for this opportunity to address your conference on The role of coal in the New Zealand energy market".New Zealand's energy market has, in common with much of New Zealand, undergone major change following the market reforms of the Labour Government.As far as the energy sector is concerned this change has been for the better, as it has created for the first time in a very long time a "true economic market" for energy in New Zealand.

Jan 1, 1990

Continuous, steady-state laboratory flotation tests showed that the recovery of cha1copyrite from a naturally occurring ore, under conditions closely resembling those of plant practice, could be expressed in terms of a first order rate equation.Tests on full-scale plant flotation cells, using impulse tracers, indicated ideal mixing of the pulp in the cells.It was demonstrated that values of first order flotation rate constants can onlv be obtained from conventional methods of analysis in special cases.Analysis of a plant sampling campaign by the author supported a first order kinetic equation for two mineral species, and for the individual size fractions of one of these.The effect of stage-addition of reagents is interpreted in kinetic terms.

Jan 1, 1966

By H Benzer, N A. Aydogan

It is well known that the high pressure grinding rolls (HPGR) can only be operated efficiently under choke feeding conditions in which a material bed is built up between the rollers to ensure interparticle breakage. By increasing the fines amount in the material bed up to a specific level with the recycling load, a uniform material bed is created and higher pressure gradient along the roller width is obtained which results in compact flakes including more fines. Extensive test work has been carried out with an industrial HPGR unit grinding cement clinker in a cement plant in Turkey. During the test work the recycling load of the circuit was changed to achieve different ratios to the fresh feed rate in order to identify the effect of the recycling load on the circuit performance. Six different tests were performed with the circuit at steady state. For each test, samples were collected from HPGR fresh feed and discharge, and total feed, then the particle size distributions of the samples were determined and mass balances around the circuit were calculated. The conclusion was that the reduction ratio of the HPGR increased with increase in recycling load. The flake densities showed the same trend with more compacted flakes being produced for higher recycling loads.

Jan 1, 2009

By DJ McKEE

Process control emerged in the mid-1960s as a new and exciting method of improving the performance of mineral processing operations. The early Australian developments, principally in Broken Hill and Mount Isa, were based on pioneering work in instrumentation, the availability of small digital computers and a particularly effective partnership between companies with technological foresight and University and CSIRO research groups. Initial progress was rapid and within ten years many plants were committed to process control. Process monitoring is now routine and most circuits have some level of control. However, few plants have comprehensive optimising control systems as the difficulty of developing control strategies which can cope with the wide variety of conditions encountered in most mineral plants has been fully appreciated. This paper summarises past experience and assesses the degree of application of different forms of process control in metallurgical plants. Barriers to the effective utilisation of opt rising control are identified and some suggestions for advancing the application of control are made.

Jan 1, 1992

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

By W Liu, S Gao, D Wei, B Cui, Z Guan, Y Shen

Beneficiation of low-grade fine-grained hematite ores becomes increasingly important due to rapid depletion of high quality iron ore resources. However, fine particles, especially ultra-fine particles, make efficient beneficiation of these ores more difficult. Therefore, methods to reduce the influence of fine particles must be considered to achieve better beneficiation performance. Analysis and systematical beneficiation tests were carried out on an ultra-fine-grained hematite ore slime from washing a fine grained hematite ore. Ore particles were found to be presented in loose soil. While some of the ore particles were agglomerated, they were very fine and contained up to 76.5 per cent -0.023 mm material. In this paper, using a single magnetic separation flow sheet with sodium silicate (SS) as a dispersing agent, a concentrate containing 65.05 per cent Fe was obtained at an iron recovery of 68.58 per cent from the hematite ore slime of 56.65 per cent Fe. The single magnetic separation flow sheet was simple and reliable, the agent SS was effective in dispersing ultra-fine particles. The results are believed to be applicable to similar hematite ores.CITATION:Wei, D, Guan, Z, Gao, S, Liu, W, Shen, Y and Cui, B, 2013. Beneficiation study of an ultra-fine-grained hematite ore slime, in Proceedings Iron Ore 2013 , pp 495-500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The Indonesian province of Papua is a remote jungle-clad region covering the western half of the mountainous island of New Guinea. Despite being relatively under-explored to this day,Papua is home to the greatest mineral success story of the 20th century. The Grasberg/Ertsberg minerals district atop the central dividing range contains the worldÆs largest reserve of both copper and gold (Freeport-McMoRan Copper and Gold, 2002). With large mines at Ok Tedi,Por gera and Lihir,and many well-delineated resources such as Frieda River,Wafi and Hidden Valley, neighbouring Papua New Guinea,the eastern half of New Guinea has enjoyed sustained exploration campaigns for gold and copper since the mid 1960s. The combined Grasberg and PNG exploration successes can be measured in terms of ounces of gold produced over the last decade versus available landmass,conf irming the island of New Guinea and surrounding islands as a world-class destination for gold explorers. Yet despite this obvious regional prospectivity and the profitability of the Grasberg operation, a sustained exploration effort in the Papua province in Indonesia has not been achieved. Periodic political constraints, poor infrastructure, high costs, operational challenges, social and environmental concerns and lack of immediate exploration success often impact exploration investment decisions. Accordingly a lesser number of mineral occurrences have been documented in Papua compared to those seen along tectonic strike in geologically similar Papua New Guinea.

Jan 1, 2004

By B Lavin, R Sanford

This paper examines the application of Lean Manufacturing in a mining environment, based on experience within the Rio Tinto entities: Rio Tinto Aluminium, Northparkes Mines and Hunter Valley Operations. The three applications have tested the flexibility of the Lean methodology. Within Rio Tinto, Rio Tinto Aluminium was the first group to introduce Lean. The rollout began in late 2004. It was introduced firstly at Boyne Smelters, Gladstone, as a model site with the initial application in the Carbon Bake Furnace area. It was later extended to other sites including the Weipa Bauxite Mine. LeanÆs successful application within Rio Tinto Aluminium was in part responsible for its recent adoption by other Australian-based Rio Tinto business units including Northparkes Mines, a copper mining operation in Central New South Wales, and Hunter Valley Operations, a group of four coal mines in the Hunter Valley region of New South Wales. Lean is also being adopted by Rio Tinto Iron Ore. Rio Tinto Aluminium introduced Lean Manufacturing to complement an existing Six Sigma business improvement program and to achieve continuous improvement activities at a workplace level. Lean provides a similar level of rigour and discipline to Six Sigma but its application is everyday and for everyone, everywhere in the workplace. It is a valuable management tool. In a short time, Lean has achieved good and sometimes spectacular results improving productivity and efficiency at all sites, including our mining site. Within Rio Tinto Aluminium, it has also had beneficial impacts on our ability to develop and retain employees.

Jan 1, 2006

By L M. Zhang, X Y. Li

Surface displacements are routinely monitored at multiple points during slope excavation. The monitoring data reveals the safety status of the slope under current loading conditions. They can be used to enhance the prediction of the future performance of the slope by reducing the uncertainties of the prediction model and its model parameters. In a multistage excavation, the observed displacements in the current stage can be used to update the prediction of the displacements in subsequent stages. Besides, due to the spatial correlation of the slope parameters, the prediction of the displacement at one location can also be updated using the monitored displacements at adjacent locations. This study aims to develop a multistep updating method to enhance the prediction of the future performance of the slope using time-series monitoring data at multiple points. This method integrates the theoretical computational model with observational evidence. It considers the inherent uncertainty of the slope, model uncertainty and measurement uncertainty. With more monitoring information being incorporated, the prediction becomes closer to the actual performance of the slope. A case study of a multistage excavation of an extremely high rock slope in south-west China is presented for illustration.CITATION:Li, X Y and Zhang, L M, 2014. Better prediction of performance of a slope using time-series monitoring data at multiple points in a multistep excavation, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 183–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

The past decade hap seen revolutionary advances in com-munications and information-handling techniques which have been stiriulated by "cold war" military requirements and by, current programmes for probing into outer space: The tools used in exploration for petroleum and minerals have been improved significantly as a result of this new space age technology and even greater improvements are on the way.Two areas of technical activity have been particularly fruitful in enhancing the effectiveness of exploration, methods. These are (1) The development of new approaches, based on information theory, for extracting signal from noise more efficiently than before, and (2) The use of high-speed digital computers for storing and processing all kinds of exploration information, not only geophysical but geological as well.In seismic prospecting, use of information theory has led to new techniques such as time-domain filtering, wave-number filtering and correlation methods which have made it possible to obtain usable reflection data from areas which were previously considered NR. Complex playback and other data processing facilities have been developed to apply these approaches.

Jan 1, 1963

By C Beal

Proper understanding and management of production drilling in sublevel cave (SLC) mines is essential for meeting production targets and for avoiding inefficiencies that could lead to costly bottlenecks. In many SLC mine management models drilling is considered a derivative activity of firing and bogging. Its scheduling is considered to be implied in a firing schedule and given an arbitrary target completion, ‘several weeks’ or ‘a month’, ahead of production firing. Like development, drilling activities are most efficient when conducted separately from other production activities. Unlike development, however, it is not apparent during planning and feasibility how far in advance of firing drilling activities ought to be conducted. This paper presents a method of defining a minimum threshold of drilled stocks above which drilling, firing and bogging operations occur most efficiently. As an example, the drilling activities, procedures, and maintenance at Glencore Xstrata’s Ernest Henry Mine are presented, and the larger scale consequences of improvements to these areas are presented to illustrate their importance in the operation of an SLC mine.CITATION:Beal, C, 2014. Understanding the role of production drilling and drilled stocks in efficient operation of a sublevel cave mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 235–242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By C M. W Boyle, E K. C Phuak, A Lewan, E Ryan, M D. Paine, P H. Mackenzie

"Rio Tinto Iron Ore (RTIO) has an extensive history in the application of geometallurgy to the iron ore value chain. Fundamental to this has been the geological logging of material types which are assigned processing attributes such as lump per cent and density. Initially these were used for product (lump and fines) grade predictions in relation to grade blocks to be used within short-term planning horizons.More recently the predictive reach of the material types and their associated processing attributes has been extended due to their inclusion into geological block models. These predictions can now be used to influence mine plans across multiple planning horizons in such a way that the extremes of geometallurgical properties can be pre-empted and managed thus improving efficiency. Spatial material type domains are also used in the planning of metallurgical drill holes to ensure greater representivity of material than was typically obtained by chemical and/or stratigraphic criteria alone.Material type logging has also been enhanced by the introduction of modern, rapid mineralogical techniques that have complemented visual logging. This has enabled the identification and quantification of contaminant minerals and their relationships with host ore types to be established. This data is used to better manage product grade predictions and identify risks to the short-term plan.Work is ongoing in RTIO to further refine logging based predictions and in addition apply them to new areas of the business. This work requires collaborative and multidisciplinary teams working on an integrated approach combining geology, metallurgy, technology and innovation, mine planning and technical marketing.CITATION:Paine, M D, Boyle, C M W, Lewan, A, Phuak, E K C, Mackenzie, P H and Ryan, E, 2016. Geometallurgy at Rio Tinto Iron Ore – a New Angle on an Old Concept, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 55–62 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By N A. S Webster

The reaction sequences involved in the formation of iron ore sinter phases were determined using in situ synchrotron-based X-ray diffraction. Experiments were carried out using a synthetic sinter mixture containing 77.36 per cent Fe2O314.08 per cent CaO, 3.56 per cent Si.O2 and 5.00 per cent Al2O3 corresponding to a basicity of ~4. The alumina content represents the upper level of alumina concentrations measured in phases formed in industrially produced plant sinter. Data were collected during heating of the sample to 1350°C under an atmosphere of 0.5 per cent O2 in N2, equivalent to an oxygen partial pressure of 5 × 10-3 atm. This temperature was sufficientto ensure melting. Data were also collected on cooling of the sample back to room temperature to examine recrystallisation of phases from the melt.Results showed the sequence of reactions initially involved the formation of calcium ferrite phases C2F and CF. These subsequently reacted with the silica and haematite leading to the solid state formation of SFCA and SFCA-1. SFCA and SFCA-1 were the last phases to form in the system and were both stable up to ~1260°C. Above ~1260°C, melting of the SFCA phases and reduction of the remaining haematite occurred producing the assemblage magnetite + melt.During cooling, both SFCA phase types recrystallised from the melt initially coexisting with magnetite until secondary haematite formed. This is the fi rst study to demonstrate that both SFCA and SFCA-1 are precipitated from the melt during cooling of iron ore sinter. Future work will extend the range of compositions studied to examine the effect of basicity and alumina concentration on the phase assemblages as a function of temperature and oxygen partial pressure.

Jul 11, 2011

By Recepoglu O, Tolun R, Yavasoglu N, Bulutcu AN

Scheelite was floated from a low-grade (0.28 per cent W03) calcitic (96.30 per cent CaCO3) scheelite ore using oleoyl sarcosine as collector and alkylated 8-hydroxyquinoline as modifier. Compared to oleoyl sarcosine alone, the grade and the recovery of scheelite concentrate were increased from 8.07 per cent to 33.54 per cent and from 55.1 per cent to 73.4 per cent, respectively. Infrared studies with pure calcite and scheelite minerals showed that while alkyl oxine is adsorbed on the scheelite surface, it is not adsorbed on the calcite.

Jan 1, 1993

By D Kay, M Lovitt

Mass Blasts are generally required at the completion of longhole stoping cycles to maximise the recovery of ore from a specific orebody. During the course of mining, the practice is to leave pillars of ore to support the opening left by extracted ore and to mitigate stresses from working areas of the stope. These pillars usually contain ore that has been included in the resource evaluation and is highly valuable to the mining operation. Due to their stressed nature, the removal of pillars by conventional blasting techniques, through small blasts, can result in pillars being reduced beyond their critical size and ultimately failing, rendering the ore unrecoverable. The AurionGold Kanowna Belle Gold Mine operates a Mine to Mill philosophy. This philosopy requires the fine tuning of blasting to provide the best possibe ore feed at the highest grade for mill productivity. This means that ore to the mill must be well fragmented from blasting that provides high extraction rates from draw points, with minimal dilution from overbreak or fall off, and sized to maximise SAG mill throughput. The AT04 Mass Blast contained significant ore reserves which were required to meet gold production targets. KBGB needed the AT04 Mass Blast to perform as well as if not better than conventional stope blasts to maintain mill production. This paper describes the circumstances, planning philosophy, techniques, including the use of Electronic Initiation Systems and Bulk Emulsion Explosives, and results that provided a highly successful outcome.

Jan 1, 2002