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Ledcap Pty Ltd has developed two software tools for assisting in the determination of life-of-mine (LOM) trucking requirements. The first tool generates haul paths and the second calculates truck travel time over these paths. The two step approach allows the paths to be viewed and if required edited, to better represent the actual site haul routes.The first tool automatically creates haul paths between the mine bench and the dump. To do this the user supplies a master haul route and a scheduled block model. The master haul path and the block model are interacted to create multiple haul routes, one for each pit/dump bench pair in each scheduling period. Each path carries with it a record of the scheduling period it represents and the dry tonnage hauled over the path in that period.The second tool calculates truck travel time over the path. Data from the manufacturer's rimpull and retarder curves are used to calculate accelerations and speed over each segment of the haul path. As the paths are derived from digitised representations of mine haul routes the path f les often have over a hundred segments. This detailed representation of the haul route allows the software to automatically adjust speed for different radius corners and accurately simulates the changing accelerations over the gradient changes that occur in real life mine ramps. Rolling resistance can be specified at a global level, at a segment level and at a period level. This allows rolling resistance to be changed seasonally as well as spatially.Life-of-mine trucking studies attempt to calculate an accurate answer from extremely variable inputs. This paper will detail the features of the two software tools and how the tools provided in the software can assist the mine planner to have greater confidence in their life-of-mine trucking requirements and the subsequent production capacity inputs to their scheduling calculations.

Dec 6, 2010

By Secis R

Northparkes Mines is located 27 km northwest of Parkes in central west New South Wales. The E26 deposit is the largest of all defined to-date in the area, containing over 50 per cent of Northparkes' resources and reserves. The combination of orebody geometry and geotechnical characteristics provide ideal conditions for the block cave method of mining of the first lift of the E26 deposit. Although this method of underground mining has been used for decades in other countries, E26 is the first example of its use in Australia. Copper-gold mineralisation at Northparkes is related to quartz monzonite porphyries that have intruded coeval Ordovician volcanics. Sulphide mineralisation (dominantly bornite and chalcopyrite) occurs principally within quartz veins associated with the porphyry intrusions. Veining and mineralisation occurs within both the porphyries and volcanics. To optimise the recovery of a resource within a block cave mine, a good understanding of the rock mass and ore flow characteristics is essential. These have a significant effect on the fragmentation size and range and on parameters such as the drawzone spacing, height of interaction zone and dilution entry. As ore within a cave column moves and mixes when material is extracted from below and beside it, the total reserve extracted is unique for a particular draw strategy/production history. Until recently, reserve estimates and production schedules were based on the application of a uniform dilution factor to the tabulated resource. However, given the complicated flow and mixing within the cave column, such a simplistic approach can produce erroneous results. Northparkes Mines purchased and sponsored the upgrading of a commercially available software package specifically developed for modelling removal of resource blocks under caving conditions. This Gemcom software package, PC-BC, has been used for mine planning, reserve reporting and production scheduling. Blocks within it resource block model are converted into a mineable reserve taking into account mixing and dilution during depletion of drawcolumns (by horizontal and vertical redistribution of insitu tonnage and metal). As PC-BC gives individual drawpoint reserves, it can be used during the planning stage to determine whether or not a drawpoint is economic. For E26 Lift I an optimal layout containing 130 drawpoints has been developed based on a nominal 14 m x 14 m drawpoint spacing and a 0.8 per cent equivalent copper (eCu) cut-off grade. Annual production schedules for the depletion of material above this layout are based on: I higher tonnage removal from higher grade drawpoints in the early years of production; and 2 drawpoint production rates proportional to the total tonnage of orr remaining in the drawcolumn up to the optimal height of draw tier subsequent years. The reserve is tabulated from the combined annual production schedules over the life of the lift. The pre-mining reserve for Lift I of E26 is 26.6 Mt at 1.43 per cent copper and 0.39 g/t gold, of which approximately 23.4 Mt will be extracted under caving conditions. By scaling down the annual production schedule, weekly drawpoint tonnage calls can be given for short-tern production scheduling.

Jan 1, 1997

Analysis of rock discontinuities, collected using a scanline method, has been undertaken at the Iron Duke open cut mine, on the southern margin of the Middleback Range in the Gawler Craton, South Australia. The iron mineralisation, which is a product of supergene enrichment of carbonate sediments, is located on the W (western) limb of a gently N plunging D2 macrosyncline. Mesofolds plunge shallowly to the NE or steeply to SE, suggesting two shortening events, of which the second produced significant macrofolds. Discontinuities include:faults and shears which display variable orientations, mainly striking WNW dipping steeply N; mesofractures or joints maintaining a well constrained orientation, dipping steeply S, subvertical striking E-W; and bedding surfaces which are folded about a gently N plunging axis. Through this example of the regional control exerted on local discontinuities, it is clear that discontinuities are not randomly distributed as often assumed in purely statistical approaches. Commonly for rocks of any age there is a distinct discontinuity pattern, reflecting the geological deformation history. If the controls exerted on local rock discontinuities can be determined and assigned a number related to their significance, the way forward is available to develop a site specifc knowledge base that can make realistic predictions for any position in a given rock mass. Such a procedure would involve assessment of the regional geology, linked to scanned discontinuities either via manual or automatic means. Recent advances in automatic scanning rock faces (eg by the I-SiTE Laser Radar) to determine discontinuities distributions, enable the rapid calculation of rock characteristics. This is a significant advance in rock engineering, providing a method of safe and quick collection of data. However it creates problems in the presence of an increase in the geotechnical data available, which should be assessed in the context of the regional geology. Although techniques are underway to analyse post-blast discontinuities, the next signifant potential advance in this area could be the integration of a knowledge based system to assess discontinuities ahead of mining, incorporating regional assessment and human intuition.

Jan 1, 2000

Phosphorus Phase Analysis of Medium-Low-Grade Rare-Earths-Bearing Phosphate Ores

Sep 13, 2010

Mining is both a high risk and a long term business. This is dramatically illustrated by the fact that, on average, the explorer will expend over $30 million in a ten year period for each significant economic discovery. The time required to complete the exploration process is one of the most substantial commitments made by any mining company. For example the time lag between the implementation of an exploration programme and an economic discovery is variously estimated to take two to ten years. The ore definition phase following discovery currently takes between two and five years while subsequent mine development may take one to two years in easy situations and up to 8 in difficult environments. In most countries the critical path through the early stages is determined largely by technical considerations but in almost all countries the path through the later phases is dictated by the plethora of permits, licences and community involvement steps.

Jan 1, 1982

Though many mining and mineral processing companies have embraced the principles of sustainable development (SD), there is still a significant challenge of applying these in a practical sense, either in plant design or as part of day-to-day operations. The high-level nature of sustainability concepts often do not translate easily into workable activities or business case evaluations. This makes it difficult for engineers and company decision makers to understand whether their actions are making a contribution to sustainable development and a long-term business case. While several organisations have their own SD tools that can, to a degree, help identify these opportunities, they are largely ad-hoc and lack the necessary thoroughness to defensibly value these opportunities. Recognising these serious shortcomings, the Cooperative Research Centre for Sustainable Resource Processing (CSRP) has undertaken the development and trial applications of SUSOP« (SUStainable OPerations), a new concept that is somewhat analogous to HAZOP and the wider risk and safety frameworks used in projects today. The key goal of the SUSOP« research project is to produce a holistic, systematic and rigorous framework for project development, capturing, recording and evaluating SD opportunities and constraints against a chosen sustainability structure (eg Five Capitals). SUSOP« is being developed through an iterative process with input from research institutions and engineering companies. This integrated approach ensures that SUSOP«, in its final form, will have the academic rigour and industry realism required to assist the resource sector contribute to societal sustainability by embedding the concepts and processes into the design and operation of their assets in a meaningful and practical manner. SUSOP« has created much traction with both engineering companies and mining and minerals operators. This conference paper presents an overview of the SUSOP« framework and its current suite of processes as well as highlighting, through practical case studies, its capability to incorporate SD considerations at different phases of an engineering project's development.

Jun 1, 2010

The Golden Cross mine is situated in a sensitive environmental setting on the North Island of New Zealand, about 150 kilometres south-east of Auckland and about 8 kilometres NW of Waihi. The mine is situated in dipping topography, with volcanic ashes making up soils, fault zones running through the area, and rainfall of about 3 m per year on average. Water management is the most demanding environmental challenge on site, and a comprehensive programme has been put in place to address tailings deposition, long term tailings storage, and water treatment during and after operations.   The tailings impoundment is built with an underdrainage system that collects groundwaters and waters that seep through the impoundment. The embankment and impoundment are both built to withstand the Maximum Credible Earthquake and the Probable Maximum Flood. Tailings are treated to remove cyanide and to decrease metal solubility to reduce long term risk to water quality after mining. A state-of-the-art water treatment plant is utilised to treat water from the underdrainage system and water decanted from the top of the tailings pond and stormwaters to remove residual cyanide and metals to extremely high standards with a great deal of reliability and at reasonable cost. Closure of the facility addresses long term post mining water quality issues, and rehabilitation of the area with wildlife habitat as a priority.

Jan 1, 1995

By E Topal

Stopes are used in several underground mining methods. Boundary determination of these stopes is generally based on simple rules of thumb. While several stope boundary optimisation techniques are available, they fail to guarantee true optimum results. The first part of this paper reviews some important stope boundary optimisation studies and proposes a new algorithm to optimise stope boundaries and layouts for underground operations. The second part applies the proposed algorithm to a block model to test its ability to produce optimum results and demonstrate its applicability in a number of different scenarios. The results demonstrate that the proposed algorithm can find optimum stope boundaries and layouts in three dimensions for different stope sizes and economic conditions.

Jan 1, 2009

East Otago gold deposits are hosted in Otago Schist that is the metamorphosed equivalent of Permian-Triassic Torlesse terrane greywackes. Relatively undeformed Torlesse sequences in Canterbury have <l m - 50 m bedding, with c. 500 m - l km and c. three kilometre scale units, typically either: 1) thick-bedded, massive, sandstones; 2) thin-bedded sandstone-argillite flysch; or 3) siltstone- or argillite-dominated units. Such lithological layering in Otago was intensely folded, deformed, and overprinted by metamorphic fabrics during Jurassic-Cretaceous regional metamorphism. Although primary sedimentary structures can no longer be recognised, a æghostÆ lithological variation is still present in Otago represented by psammitic (sand-derived), interlayered (sandstone-siltstone derived) and pelitic (siltstone-mudstone derived) schist. Lithological æunitsÆ in the schist are typically either 20 100 m or c.1 - 2 km thick, and are oblique to faults and shears hosting gold mineralisation at Macraes, Barewood, Nenthom, and Oturehua. Lithological variations and folds in lithological units are important in the along-strike distribution of gold in these deposits, and in the development of relatively high-grade pods and shoots at l00 m - 1.5 km scales. Ramps, flats and step-overs (known to be locally important for controlling mineralisation) are commonly located at lithological boundaries, presumably by local refraction of faults or shear zones as they propagated through folded stratigraphy. The various lithologies have also responded differently to deformation, causing variations in permeability that affected the penetration of mineralising fluids. Mapping lithological variations in barren host-rocks, either directly+ by fieldwork or indirectly by aerial geophysics, is a key to understanding and predicting the distribution of gold at mine and deposit scales.

Jan 1, 2001

The mercury, gold, silver, copper, lead and zinc values of soils over altered and mineralised rock were determined to establish the potential use of mercury as an indicator element in geochemical prospecting. The results are presented to show that mercury can be used successfully in prospecting for precious metal mineralization in the Thames-Waihi area.

Jan 1, 1979

Many sampling standards arrive at a value for the prescribed sample mass by assuming a specific relation between the sample mass and the relative standard deviation of the fundamental error and assigning a value to the tolerated coefficient of variation. In order to obtain an equation that provides a relation between the minimum sample mass and the particle properties, many different models for the drawing of a sample have been developed. Here, a model for the drawing of a sample is proposed which can be considered to be a generalisation of the model used in GyÆs sampling theory. Using simulations, it is illustrated that the generalised model can lead to a better correspondence with actual sampling processes.

Jan 1, 2005

By R J. In, C Moore, P J. Moffitt, T Hansen

Telfer Gold Mine combines a world-class gold and copper resource and longevity of operation as a major gold and copper producer. Telfer Gold Mine has undergone a series of transformations since mining commenced as a high-grade narrow-vein oxide open pit operation in 1977. In 1986, the open pit operation converted from a narrow-vein, high-grade operation, to a low-grade high-volume oxide mining operation utilising dump leach processing technology. Mechanised underground mining of the high-grade narrow-veins commenced in 1990. Total recovered gold production between 1977 to 1999 has totalled 5.7 million ounces. The Telfer Extension Project consists of two pre-feasibility studies, the Surface Extension Project (SEP) and the I-Series Project (ISP). The combined studies represent one of the more significant resource evaluations undertaken in the gold industry in recent times. Geological activities for the SEP pre-feasibility study have included the drill definition of a large low-grade resource within an area of 25 km2 . The surface drilling program has completed 15 000 metres of HQ3 diamond drilling and over 30 000 metres of RC between last quarter of 1998 and late-1999. The ISP pre-feasibility study is currently evaluating the resource potential of both a high-grade low-volume and a lower grade bulk mining scenario, 800 m to 1200 m below the surface of Main Dome. 15 000 metres of underground diamond drilling have been completed between last quarter of 1998 and August 1999 as part of this study. Systems and cultures have been developed to maximise safety, monitor the quality assurance/quality control (QA/QC) on all aspects of the operation, and minimise impact on the environment. All data are stored in database systems, specifically designed for Telfer operations. 3D geostatistical resource estimation using ordinary kriging has been carried out for over 220 geological domains within the 25 km3 of mineralised system. Non-linear geostatistical techniques are being investigated as part of the pre-feasibility study.

Jan 1, 2000

By H Han, L Lu

Due to the international depletion of reserves of traditional high-grade iron ore, the ore resources available throughout the world, especially in steel mills in East Asia, have changed drastically from hard hematitic to more goethitic ore types, such as pisolitic and Marra Mamba ores. The level of impurities and loss on ignition in iron ore has also been slowly increasing. Finally, the proportion of fine material in the available products has increased considerably for most iron ore fines. This has been found to have significant impacts on sinter quality and sintering performance. Magnetite concentrate is typically high in Fe grade and releases extra heat when oxidised to hematite. The amount of magnetite concentrates is expected to increase due to the recent development of a number of magnetite projects. Some of these magnetite concentrates will end in sinter blends. This will not only improve the sinter quality and but also have a beneficial impact on the fuel consumption of the sintering process. However, most of the concentrates available are very fine, which will negatively impact the green bed permeability and consequently the productivity of the sintering process. This paper reviews and comments on the recent technological advances in sintering with high proportions of magnetite concentrates.CITATION:Han, H and Lu, L, 2017. Sintering technologies of sinter mixtures containing high proportions of magnetite concentrates, in Proceedings Iron Ore 2017, pp 31–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

This paper discusses the prediction of subsidence over partial extraction systems in thick coal seams. A model based on empirical techniques using influence functions is developed to calculate the surface ground settlements above extraction panels. Independent of the influence function, two field parameters, the subsidence factor and the angle of draw (limit angle) are required to define the model. Both these parameters are best observed from critical or super critical subsidence areas. However in thick seams, extraction widths are typically sub critical and therefore it was necessary to refine an estimation process for sub critical conditions. Partial extraction systems in NZ are characterised by variability with respect to extraction thickness and depth. As extraction proceeds along a panel, conditions deteriorate once the critical span width is exceeded and therefore percentage extraction decreases. A further variable was introduced to the modelling which allows for varying extraction sequences. Two comparisons with field observations, one over a partial extraction panel, the other over abandoned workings, showed the method gave good agreement to measured subsidence values.

Jan 1, 2002

By Y Xie, L O’Connor, S C. Dominy

Sheeted vein gold deposits are characterised by multiple subparallel veins and often free milling gold. Variability in gold grade and recovery parameters are enhanced by poorly designed sampling and test work protocols. Poor quality samples generally equate to an enhanced nugget effect. A sample can be described as being representative when it results in acceptable levels of bias and precision. Total sampling variability can be quantified by the relative sampling variance, which measures the total empirical sampling variance influenced by the heterogeneity of the lot being sampled under the current sampling / test work protocol. Effort should be made to minimise the relative sampling variance through Theory of Sampling (TOS) and quality assurance / quality control (QA/QC) application. This contribution reports on a case study that exemplifies how high-quality grade and recovery data can be gained from a well-designed and planned drilling, sampling and test work program, followed by bulk sampling. Results across historical resource drilling, geometallurgical drilling, laboratory assay / test work, geometallurgical modelling and a bulk sampling/pilot processing study are reconciled. A whole core, entire-sample test work protocol was used to acquire fit-for-purpose gold grade and recovery data for inclusion into a Pre Feasibility Study reported in accordance with the JORC Code.CITATION:Dominy, S C, O’Connor, L, Xie, Y and Glass, H J, 2017. Geometallurgical sampling protocol validation by bulk sampling in a sheeted vein gold deposit, in Proceedings Eighth World Conference on Sampling and Blending , pp 185–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Finlayson E, Hilyard D

1:100 000 geological mapping of Bougainville Island has resulted in refinement of stratigraphic subdivisions and relationships. We subdivide the sequence into basement Atamo Volcanics (Late Eocene-Early Oligocene), consisting of spilitised pillow basalts, which are overlain unconformably by Late Oligocene-Early Miocene Keriaka Limestone. The latter is unconformably overlain by fine-medium grained volcaniclastics and minor lavas of the Middle-Late Miocene Toniva Formation which coarsens upward and passes gradationally and conformably into the coarsely volcanolithic latest Miocene-Pliocene Arawa Conglomerate. The Kupei Complex, host to the Panguna.porphyry Cu-Au deposit, consists of medium - K20 microdiorites, granodiorites, and andesites intruding Arawa Conglomerate and Toniva Formation. K/Ar isotopic dates on the Kupei Complex range from 4.8-1.3 Ma, and hence overlap the age of the Arawa Conglomerate. We believe that the Arawa Conglomerate consists of mass flow deposits on a volcani- clastic apron surrounding a volcanic edifice above the intruding Kupei Complex.

Jan 1, 1990

By G B. Smith, D Hillier, T Gibbons, D B. Donato, M D. Adams, S Davies, R S. Schulz

Responsible management of cyanide solutions and tailings on gold processing plants worldwide is an important aspect to these operations and is regulated via guidelines provided by the International Cyanide Management Code, an industry initiative designed to minimise cyanide risk to operators and the environment. Here we demonstrate the unprecedented causal relationships surrounding the saline (>14 000 mg/L total dissolved solids - TDS) and hypersaline (>50 000 mg/L TDS) cyanide solutions in gold plant tailings in the Central Goldfields of Western Australia, resulting in zero wildlife mortalities on three sites over the study period of almost one year. Wildlife interaction and ingestion is significantly lower than that experienced at other gold mine sites, with more rapid degradation of weak-acid dissociable (WAD) cyanide within the tailings storage facility (TSF). A rigorous chemical sampling using a novel æminimal accessÆ robotic sampler device and wildlife observation exercise was carried out at two hypersaline mine sites: Barrick Kanowna Belle (BKB) and Gold Fields St Ives (GSI) and one saline site, Barrick Granny Smith (BGS). The data was compared with available reported chemical sampling and wildlife observation data from a previously operational fresh water site (<2000 mg/L TDS) that had experienced wildlife mortalities, Case Study D (CSD). The comprehensive body of work, along with cyanide degradation test work carried out in the laboratory, was analysed via hypothesis development and testing, causation analysis and dynamic chemical modelling. The non-mortality effect on these sites appears to hold over a further four years of routine wildlife and cyanide monitoring by site personnel. This study has helped these three mine sites achieve and maintain full Compliance Cyanide Code status over a significant period while removing the need for operating the detoxification plants they would otherwise have required.CITATION:Adams, M D, Donato, D B, Schulz, R S, Smith, G B, Gibbons, T, Davies, S and Hillier, D, 2013. Hypersaline-induced reduction in cyanide ecotoxicity at gold operations, thereby obviating detoxification plants, in Proceedings World Gold 2013, pp 489-502 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

Effects of Hydrated Mg2+ on KCl Flotation

Sep 13, 2010

By S F. Simmons, J Fleming

Alteration and mineralisation at the Island Copper deposit is related to the intrusion of Early Jurassic quartz feldspar porphyry dykes into surrounding comagmatic Bonanza volcanic rocks. The pyrophyilite alteration zone forms an upward flaring cone, largely hosted within a breccia body that cross-cuts the Co, Mo, and Au-rich ore shell. This alteration zone contains pyrophyllite, dumortierite and diaspore and resembles alteration occurring in some high-sulfidation deposits, but which is barren. Fluid-mineral equilibria and fluid inclusion studies indicate formation at approximately 300 ¦C from fluids dominated by steam and gases. These fluids appear highly acidic, but sulfur poor, leading to extreme base leaching within the breccia body and surrounding rocks.

Jan 1, 1995

Column Bioleaching of a Low-Grade Nickel-Bearing Sulfide Ore Yellow Mountain Deposit belonging to GobiMin Inc is located in the Chinese Tianshan and Altay orogenic belts, Hami, Xinjiang Province, NW China. Indicated Mineral Resources of its reserve are estimated at 12 million tonnes averaging 0.40 per cent nickel. Mineralogical examination and chemical analysis indicated that the Yellow Mountain ore is a type of high Fe, low Mg and low Ni sulfide ore: the main sulfide minerals are ~8.0 per cent pyrrhotite (Fe1-xS), ~1.0 per cent pentlandite ((Fe, Ni)9S8), ~0.6 per cent chalcopyrite (CuFeS2), ~0.5 per cent pyrite (FeS2), and ~0.2 per cent violarite((Fe, Ni)3S4); the main gangue minerals are ~48 per cent olivine, ~28 per cent antigorite, ~3 per cent chlorite, ~2 per cent talc, ~2 per cent tremolite, and~1.5 per cent magnetite; the chemical analysis of the ore sample are Ni 0.40 per cent, Co 0.016 per cent, Cu 0.24 per cent, Fe 12.4 per cent, S 5.6 per cent, MgO 9.6 per cent, CaO 1.80 per cent, SiO2 48.5 per cent and Al2O3 10.3 per cent. Preliminary results of the shake flask test showed that pyrrhotite is easily leached and the high concentration of ferric iron would hamper the growth of bacteria which will bring a negative impact on the bioleaching conversely. This work aims to set up a method to prevent the negative impact of the ferric ion on the bioleaching of the ore. Two method were combined to prevent the negative impact of the ferric ion, they are adaptation of the mixed bacteria to iron ion and bleeding the off-solution periodically to control the levels of iron ion (depending on the tolerance of the microorganisms to the ferric ion) in the leaching solution. Using a mixed mesophiles composed of Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans under room temperature, a nickel recovery of 93 per cent and a cobalt recovery of 85 per cent were achieved in 280 days column bioleaching process with an average nickel concentration in the leaching solution of 2.6 g/L. The results showed that the negative effect of the ferric ion can be successfully controlled and the nickel can be bioleached successfully from theYellow Mountain ore.

Sep 13, 2010