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By T R. Gibbons, I Grayand

Geotechnically massive strata may lead to a host of problems during longwall mining. These include windblast on initial goaf fall, sudden loadings on powered supports, periodic weightings, fractures that may propagate to surface, and extreme subsidence problems. It is essential to identify these problems prior to mining and to appropriately deal with them. The problem is essentially that the rock mass does not breakup evenly and when it does so it tends to produce large blocks which may suddenly move. The rock types that produce these problems tend to be massive sandstones, massive siltstones and sometimes igneous sills. The fundamental problem with these is that they do not breakup readily. This is because the ratio of stress they are subject to compared to their strength is low. Thus, the shallower mines with lower stresses are more subject to this problem than deep highly stressed ones with similar strength rock.

Nov 29, 2022

By Lewis W. H, Leigh M. C, Mayercheck W. D

The U. S. Department of Interior's Bureau of Mines, in conjunction with a cooperator in the U. S. A., are developing a new highwall mining system (HMS) for coal extraction in unreclaimed and active contour strip mines. This prototype system is comprised of a computer-based remote control (CBRC) system to monitor and remotely control a thin-seam continuous miner (TSCM) and a 76*m long multiple-unit continuous haulage (MUCH) conveying system, plus other manually- operated support equipment located on the highwall bench. The TSCM and MUCH coal haulage system are both controlled remotely by a single operator in a protective enclosure at an ergonomically- designed workstation located on the highwall bench. Two other personnel work on the bench to operate other support equipment. Full-scale mock-up fabrications were employed in the design of the unique remote control operator workstation. The HMS should allow the safe and economical exploitation of increased coal reserves where they outcrop in hilly regions of the United States. It should also be competitive with conventional auger mining and other coal extraction techniques, with a productivity goal at a highwall site of 20 tonne/man-h. Extensive simulated surface tests of the miner and haulage system should be completed in early 1988 at Bureau test facilities at Pittsburgh, Pennsylvania. These will be followed by actual coal production trials of the entire system in 1988 at a highwall site in West Virginia/USA.

Jan 1, 1988

By J W. Lee, E Baafi, N Aziz

Ground subsidence due to mining is a common dilemma confronting the underground coal mining industry. The effects of underground longwall mining on river valleys have come under scrutiny, especially when mining is located underneath catchment areas. As public awareness of mining impacts on the environment increases, there is the need to develop damage mitigation strategies. Results of numerical modelling show that river valley response to underground longwall mining can be simulated and evaluated.

Jan 1, 2005

In the- past, at Great Boulder Gold Mines Ltd,, ,' s.. number of attempts ' ha'tre been made to remove water ' `solublo copper and' iron sa'lt's from calcined pyritic concentrates, but various problems have arisen and the methodsi ve been abandoned. A method of rapid washing has now been developed,, and although some problems still. exist,, a workable `process has boreh established .which. has; resulted in 'substantial savings of 'reagents used for. the. cyanidation of calcine

Jan 1, 1964

By Armstrong M

The Clermont Coal Mine will export steaming coal from the Wolfang Basin in Central Queensland, Australia. It is expected to be developed in the mid-1990s.The majority of the reserves lie in the 30 m thick Wolfang Seam. Overburden depth varies from 80 m at the subcrop line to 190 m in the centre of the basin.

Jan 1, 1992

By J Isarua, R Mabiria

The Ok Tedi copper and gold project, located in the Western Province of Papua New Guinea, commenced operations in 1983. The open cut mine has undergone several significant transformations throughout its project life including changes of ownership, mine life extensions and varying production performance profiles. As of today, the Ok Tedi Mine is a 100 per cent PNG owned company (67 per cent State and 33 per cent Western Province and Communities) and has a life-ofmine plan extending out to about 2032.

May 5, 2022

By P B. Swart, P D. Erskine

Despite an increasing focus by media, communities and activists driving an elevated regulatory focus in Australia and indeed some other mining jurisdictions, the mining industry globally has had limited successful mine lease relinquishments and transfers to support a next land use.Critique from anti-mining lobbyists frequently uses the large estimates from historically abandoned mine sites to influence risk-averse regulatory reforms to improve environmental performance. The mine rehabilitation regulatory processes in Australia, and specifically in the State of Queensland, are thus largely in place to prevent mining operators from abandoning their obligations.Regulatory responses to the lack of mine rehabilitation and closure performance in the last five to ten years have primarily focussed on compliance and enforcement of rehabilitation conditions in environmental approvals. Additionally, financial assurance measures have been tightened to protect against abandonment of rehabilitation obligations by the Industry, including the Chain of Responsibility legislation (Queensland Government, 2016b) in April 2016, to hold to account those who have benefitted from mining and processing/refining projects, and then avoid their environmental obligations.CITATION:Swart, P B and Erskine, P D, 2018. Are our closure planning and regulatory processes adequate to identify, quantify and appropriately transfer residual risks after successful mine rehabilitation?, in Proceedings Life-of-Mine 2018, pp 155–158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

The Division of Minerals and Geochemistry in collaboration with three mineral exploration companies, Mawson Pacific Ltd, Ramsgate Resources Ltd and Tectonic Systems Pty Ltd commenced a two year research project to investigate the application of remote sensing techniques to exploration for mineral deposits in access of the Yilgarn Block in Western Australia. The project utilizes satellite data such as day and night imagery from the NOAA-AVHRR (National Oceanic and Atmospheric Administration - Advanced Very High Resolution Radiometer) satellite. The recent research with the imagery in the Kalgoorlie, Southern Cross and Mt Magnet regions has highlighted the advantages of the mid infra-red and the two thermal response channels of NOAA-AVHRR for geological investigations. These three channels have the spectral resolution to distinguish stratigraphic units and younger intrusive bodies, and to delineate fracture zones and shear zones associated with Proterozoic dykes. But most important is the capacity to distinguish thermal signatures from geological structure, near-surface outcrop and palaeochannels which have been covered by unconsolidated sediments. The research project applies remote sensing methods including enhanced satellite imagery optimised to the Western Australian environment. It encompasses data from both space and airborne monitoring platforms that have obsreved a significant spectral response for the classification of alteration zone lithologies. It includes the collection of multiseasonal data from areas of interest which is essential both for the understanding of thermal characteristics of important lithologies and for the extrapolation from field work investigation to potential exploration areas. No comprehensive investigation of this type has been carried out within the Yilgarn goldfields.

Jan 1, 1987

By I Zulkarnain, H Permana, R A. Binns

Through an ambitious but relatively low-cost program of marine fieldwork, laboratory investigations and technology-transfer and training activities, three Indonesia-Australia-led marine expeditions were undertaken aboard KR Baruna Jaya VIII between 2001 and 2003. These IASSHA (Indonesia-Australia Survey for Submarine Hydrothermal Activity) cruises have sought to discover and investigate a variety of potential ore forming hydrothermal systems in a range of tectonic settings. All cruises have been successful, both scientifically and from the point of view of training, creation of capabilities and capacity building for such research in Indonesia. Over 60 scientists and technicians from Indonesian and Australian institutions and agencies have been involved. Three new sites and a possible fourth site of hydrothermal activity were discovered in the Sangihe arc in northern Sulawesi. Surveys in the Tomini basin tested a hypothesis based on previous data which suggested this might be an isolated anoxic, brine-filled basin over 2000 m deep where igneous heat sources existed to generate hydrothermal mineralisation. The bay, however, was found to be open to adjacent deep ocean circulation, and there was no evidence of massive base metal sulfides. Subdued evidence of hydrothermal activity was found in the Sunda Strait associated with the famous Krakatau volcano and the extension of the seismically active Semangko Fault. The BANDAMIN program (Indonesia-Germany) covered a portion of the Banda arc in eastern Indonesia, and also found evidence of recent hydrothermal activity and epithermal sulfide mineralisation.

Jan 1, 2004

By S Wan, F Zhang, J You, K Tang, X Tang, C Bessada, A Canizarès, Q Zhang, L Lu

Microstructure of CaO-SiO2-based glassy samples with various Al2O3 contents were examined quantitatively by Raman spectroscopy and 27Al MAS NMR (magic-angle spinning nuclear magnetic resonance). Sequence of multiple cluster models of aluminosilicate system modified with Ca2+ and Na+ cations have been designed, and Raman spectra simulation were carried out after geometric optimisation by quantum chemistry (QC) ab initio calculation. The functional relationship between Raman scattering cross-section (RSCS) and stress index of silicon-oxygen tetrahedron (SIT) for aluminosilicates was established, which was applied to the calibration of experimental Raman spectra. Some five-fold coordinated aluminium (AlV, around 5 per cent) and less than 2 per cent sixfold coordinated aluminium (AlVI) were detected by 27Al MAS NMR, while most of aluminium remained in tetrahedral sites (AlIV). The hyperfine quantitative results of Raman spectroscopy and NMR showed a gradually production of AlIV with addition of Al2O3, along with the significant adjustment of Qi species distribution, in which Q1, Q2 reduced and fully polymerised Q4 increased while Q3 showed a non-monotonic variation and obtained the maximum at Al2O3 = 18 mol per cent. Furthermore, the effects of aluminium to bridging oxygen bond types (T-Ob, T = Si, Al) and the degree of polymerisation were also discussed in detail. The evolution of microstructure and its correlation with the viscosity of CaO-SiO2 based melts, incorporating various Al2O3 additives, have been investigated by employing in situ high temperature Raman spectroscopy at 1823 K and viscosity model. These structural features related to composition are essential theoretic foundation to understand their properties. The average Qi evolution culminates in an overall enhancement of the degree of polymerisation. Viscosity was determined utilising a rigorously selected viscosity model, elucidating a consistent upward trajectory as Al2O3 content is incrementally added. Furthermore, a quantitative analysis of the relationship between viscosity and structure was conducted based on the average number of non-bridging oxygen per network-forming tetrahedron (NBO/T). It provides valuable insights for examining and predicting viscosity behaviour of aluminosilicate systems.

Aug 21, 2024

By S Nkwanyana, I Govender

Batch experiments in a 0.6 m diameter mill have shown that improvements of about 13 per cent in the efficiency of energy utilisation can be realised in ball mills by replacing 25 per cent of the ball charge by an equivalent volume of cost-free critical size pebbles from AG/SAG mills. For a mill of a given size, speed and charge filling, the rate of size reduction of ore particles depends on (i) the frequency of grinding media collisions (ii) the probability of capture of ore particles between the colliding grinding media (iii) the probability of fracture of the captured particles. The probability of fracture depends on the magnitude of collision energy. The distribution of collision energy into shear and impact events determines the relative strengths of attrition breakage and impact breakage. The efficiency of energy utilisation depends on which of the two mechanisms of breakage is more desirable in a particular milling stage. In this paper collision data from a series of DEM simulations of a mill charged with steel media and a mixture of steel media and pebbles is presented in energy spectra and spatial distribution maps. The data provides the necessary detail to elucidate the improvements in the efficiency of energy utilisation in ball mills when using a mixture of pebbles and steel media.

Aug 24, 2022

The Sao Chico gold project is located on the Tocantinzinho trend which is the most mineralised zone in the Tapajos Mineral Field of Brazil (see Figure 1). The Tapajos goldfi eld was the site of the biggest gold rush in Brazilian history in the late 1970s and 1980s when approximately 500 000 garimpeiros (artisanal miners) rushed to the area to exploit extensive areas of newly discovered alluvial gold. Approximately 20 - 30 million ounces of gold were produced from these operations before the easily won alluvial gold deposits were largely depleted. The Tapajos region has had little exploration by modern exploration methods compared to any other equivalent gold fields in the world. The gold occurs in sulfide veins developed in shear zones within Proterozoic granites. Gold grades vary from approximately 15 g/t in the hard rock veins, to up to several ounces per tonne in the supergene weathered upper portions of the veins. Goldbearing vein zones in the weathered profile are free digging. In addition, tailings dumps from previous mining operations contain gold grades of approximately 1 g/t. Metallurgical test work conducted to date indicates that gold recoveries of at least 70 per cent can be achieved via gravity concentration. Gold Anomaly, via its 100 per cent owned Brazilian subsidiary, Gold Aura Do Brasil Mineracao Ltda (GOAB), plans to mine the tailings and weathered vein material by open cut methods to generate a quick cash fl ow and to provide a better understanding of the mineralisation as part of a feasibility study for mining the underlying sulfide zone mineralisation (see Figure 2). Mining will utilise locally hired excavators and trucks and ramp up to a rate of 100 tonnes per day. To treat the gold-bearing material, GOAB has purchased an integrated 'state of the art' gravity concentration processing plant from Gekko Systems of Australia. The processing plant includes a scrubber for clay and oversize removal, coarse gold gravity separation via an inline pressure jig and an inline spinner; and fine gold gravity separation via a Falcon Concentrator. The plant is expected to be operational by late 2010. This is an ABSTRACT ONLY. No paper was prepared for this presentation. 

Aug 1, 2010

By G Bournival, Y Saavedra Moreno, S Ata

Flotation frothers are heteropolar molecules that are preferentially adsorbed at the bubble interface to enhance the flotation performance by promoting the formation of small and stable bubbles. Frothers have different characteristics that can be used to classify them. A classification framework has been recently presented by Saavedra Moreno et al (2022) to classify non-ionic frothers by conducting a principal component analysis (PCA) and a hierarchical clustering analysis (HCA). However, for the purpose of the present research, only five frother characteristics, including molecular weight (MW), hydrophile–lipophile balance (HLB), critical coalescence concentration (CCC), the minimum Sauter mean diameter (DL), and foam stability index (DFI) were used in the PCA and HCA. All those characteristics were evaluated for a two-phase system in the absence of particles. Realising the important role that particles play in froth stability and behaviour, the effect of hydrophobic particles on the presented frother classification framework was investigated in this study. Four frothers with different characteristics, methyl isobutyl carbinol (MIBC), 1-pentanol, tri (propylene glycol) (TPG), and tri (propylene glycol) methyl ether (TPM), were chosen. The experiments were carried out in the presence and absence of silica particles esterified with 1-pentanol. It was evident that the results for 1-pentanol, TPM, MIBC, and TPG in the three-phase system agreed well with the frother classification presented for the two-phase system as frothers were clustered in the same groups. The findings from this research support the use of the frother classification system presented in two-phase system to select a specific frother for a particular application without the necessity of conducting laborious experiments in a three-phase system.

Aug 24, 2022

The Warraua and Mount Poole Inliers form part of a discontinuous series of basement complexes in the northwestern corner of New South Wales. The Inliers comprise mainly clastic sediments of low metamorphic grade (Wonominta Beds) and minor sills, dykes and intrusives, particularly within the Mount Poole lnJier. The Warratta rnlier has received attention due to the occurrence of auriferous quartz-veins where reef mining activities havetaken place.The deformational history of the Warratta and Mount Poole Inljers is characterised by a continuous subhorizontally WSW-ENE directed compression. Deformation was associated with the development of NNW-trending and steeply west-dipping major faults, which bound or biscct the inliers. Chevron folds and a penetrative axial planar cleavage characterise the deformational architecture and document crustal shorterung of at least 40 per cent. In zones adjacent to the major faults and within pelitic and semi-pelitic uruts, a multiple deformational evolution becomes apparent, comprising two events (D1 and D2). Deformational structures considered significant in this study were the result of D1. Tight, northeast-vergent fold patterns FI' and associated axjal plane cleavage SI' and reverse dip-slip movements at major faults indicate early northeast-directed thrusting during D1. This was followed by dextral strike-slip deformation displayed by tight, recumbent folds, en-echelon fold patterns (F2'), a northeast trending crenulation cleavage (52'), and two sets of second order faults, the latter showing high angular relationship to the major faults. A final stage of the deformational history (D2) is represented by WSW-ENE trending kink folds (F2).Auriferous quartz veins, predominantly occurring within pelitic and semi-pelitic units, were generated syntectorucally during the early deformational event (D1) in the course of commencing development of cleavage (S2'). Vein textures point towards vein formation by repeated hydrauJjc fracturing and fracture healing (crack-seal process), and by simple accretionary vein growth. Folded pelite-dominated horizons, considered as low permeability units, are suggested preferential sites where migrating metamorphic Ouids pooled and were trapped, causing high fluid pressure.Hydraulic fracturing and vein precipitation was controlled by lithology and structural constraints such as cleavage.K-Ar dates of approximately 440 Ma (Benambran Orogeny) marking the peak of metamorphism, and coinciding with the development of cleavage S1', also indicate the time of auriferous quartz-vein formation. A period of deformation of at least 30 Ma is proposed for the development of cleavage S1', as constrained by K-Ar dating and the intrusion of a syntectonic granitoid, the Tibooburra Granodiorite.

Jan 1, 1992

Bauxite Resources Limited is grade drilling in its Western Australian Darling Range tenements to firm up resource definition and to develop mine plans. The Darling Range bauxite is generally in shallow deposits with minimum overburden. In the northern tenements, the ore is characterised by a higher silica layer which may extend from 0.5 to 1.5 m below, which high grade bauxite is found to a depth of four to 7 m. When grade drilling samples are taken, every 0.5 m and the recovered sample is weighed, logged and bagged. To eliminate splitting errors, the whole sample over the short interval is pulverised. Twinning holes variations are observed when using various drill rigs. Diamond core has been shown to give close to 100 per cent recovery and grades have been verified by digging bulk samples. As such, diamond core is used as the reference. It is intended to include sonic drilling as an alternative to diamond cores. This presentation details and attempts to explain the reasons for the observed variations in the various drilling methods used by Bauxite Resources Limited. This is an ABSTRACT ONLY no paper was prepared for this presentation.

Mar 1, 2010

By Dalzell R. W

A Conveyor Belt Fire Test Program was initiated in 1985 by the Approval and Certification Center (A&CC), Mine Safety and Health Administration (MSHA), U.S. Department of Labor. The purpose was to evaluate the effect of entry air velocities on the burning properties of mine conveyor belts and assess fire test data from large- and small-scale tests. Belts meeting the fire-resistant standards of MSHA and agencies of other countries were tested in small- and large- scale fire tests.

Jan 1, 1988

The fundamental natural ingredient of any mining development is an ore reserve. The classical definition of an ore reserve has both technical and commercial components, each involving elements of risk. By definition the desposit must contain mineral values which are "extractable at a profit". Metallurgy supplies a vital link between these two basic requirements of a successful mining project; the metallurgical input establishes the process by which the contained minerals may be recovered and converted into marketable product(s).

Jan 1, 1983

The paper contains the publication of timber shapes recovered from the Burra Mines during open cut operations in the 1970s. The timber was in the process of being disposed of for fire wood. All timber shapes still in existence in September 1990 were drawn.The collection revealed a number of different types of caps and legs. There were also end plates and wall plates from what appeared to be a hanging sets of shaft timber.

Jan 1, 1993

By R Grogan

Nautilus Minerals (Nautilus) is a sea floor resource exploration and development company focused on developing the Solwara 1 Project, a copper-gold sea floor massive sulfide deposit in the territorial waters of Papua New Guinea, for which it holds a mining lease and associated environment permit.During the environmental impact assessment and project development phase, Nautilus completed a number of hydrodynamic modelling exercises in order to predict the nature, volume and extent of the plumes likely to be generated by the sea floor mining tools and return water discharge at the sea floor.The modelling was conducted using the suspended sediment fate model (SSFATE), developed by the United States Army Corps of Engineers and RPS APASA engineering consultants. The SSFATE model was originally developed in order to predict and manage dredging plumes, and has since been adapted for deep ocean sea floor mining. The model uses a Lagrangian approach to remove the limitations of grid resolution, and simulates far-field effects of sedimentation plumes by assuming that the average transport and turbulence associated with currents are dominant over the initial turbulence at the release point. The random walk procedure utilised in the model tracks particle size classes as they disperse and settle, and also takes into consideration any re-suspension that may occur following settlement (RPS APASA, 2014).CITATION:Grogan, R, 2016. Predicting, assessing and managing sediment plumes generated by sea floor mining, in Proceedings Life-of-Mine 2016 Conference, pp 124–127 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

The mill area of PT Freeport Indonesia is located in a valley surrounded by steep natural slope, characterised by extreme topography with mountains rising to above 4500 m within 100 km from the seashore. The valleys are deeply embedded into the mountainous terrain and bordered by steep natural slopes. Vertical or overhanging lime walls are interrupted by steep vegetated screen sections containing accumulated loose material from weathering processes and ancient rock falls and/or debris flows/avalanches. The climate can be best described as alpine subtropical with an accumulated rainfall of more than 5000 mm per year. Occasional snowfalls and superficial freezing above 4000 m elevation leads to heavy weathering of the superficial rock layers and along open joints and fractures. The mill area is a crucial and strategic infrastructure for the entire mining operation which is best characterised as a high density industrial area with facilities including water tanks, power generators, crusher, and concentrating facilities including office buildings and workshops as well as access tracks to the underground mining blocks. Considering the local topography, the restricted space conditions and the number of technical installations, the facilities are likely to be affected and highly vulnerable to rock fall from the surrounding slopes. In order to minimise the rock fall hazard three rock fence barriers area were constructed at the mill area. The 7.5 rock fence barriers were designed with the maximum capacity of 5000 kJ. These are the largest capacity of rock fall barriers ever constructed in Indonesia. The total length of the barriers for the three locations was 126 m. The biggest challenge of this project was the construction of the barrier at West Gulley, which was constructed at 300 m above ground level. For this site, construction access was undertaken using helicopter. This presentation discusses the design of the mitigation structures as well as the construction approach and stages of the barriers. Please note: This paper is abstract only.

Nov 25, 2010