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By J E. Everett, K Jupp, T J. Howard

Simulation modelling is a practice commonly used in the mining industry to evaluate alternative process designs. Such modelling is typically undertaken as an optimisation study to increase the efficiencies, productivity and product quality of operating mines. In this situation, real short-term grade variability data of extracted ore are available from production records as input data into the simulation.There is also a need for simulation modelling to be performed before mines are approved for construction to clarify the grade variability characteristics that can be expected from the operating mine and assist in the optimisation of the process design. In this situation no historical short-term grade variability data are available. To achieve meaningful and reliable results from a simulation it is necessary to have input data for the ore to be extracted from the pits, representative of the short-term grade variability that would be expected for the operating mine.This paper describes an example of a path taken to generate realistic input data.A method described as composite cut-off criterion was used to distinguish ore from waste, which gave substantially greater recovered tonnage at target grade compared to the conventional quadrant cut-off grade criteria.The only data available for the project was resource model data in the form of kriged block models, which are known to underestimate true ore grade variability. To achieve realistic results from the simulation it was essential to increase this variability while maintaining the accurate average grades. Areas of certain deposits that were modelled using both kriging and conditional simulation estimation techniques were quantitatively compared to establish the comparative variance and the kriged data was modified to match the conditionally simulated variance.A realistic mining model was generated via a process of discretisation and regularisation of the resource blocks. Quantitative assessment demonstrated that this method adequately compensated for ore dilution and that adjustment for ore loss was not required due to an ore skin surrounding the edge blocks.The conditioned data was then used to generate a schedule of daily mine extraction, considering grade variability, tonnage, equipment constraints and extensive blended-in-blended-out precrusher stockpiles to feed into the process design simulations.For the precrusher stockpiles a number of alternative allocation criteria were examined for ore being extracted from the pits to identify the best method in achieving reduced variability through the daily scheduling system. The study concluded that a single analyte separation criterion produced acceptable variability with minimal complexity.The blending efficiency of manually stacked and reclaimed precrusher stockpiles was studied to determine a realistic blending efficiency within the pile. A recommended method of building and reclaiming was determined to give maximum blending efficiency.Finally, the data was used as input into process design simulation models; simulation from crusher feed to shiploading demonstrating that control of shipment grade variability was achievable and that the conditioning of the data delivered realistic results.CITATION:Jupp, K, Howard, T J and Everett, J E, 2013. Generating synthetic data for simulation modelling in iron ore, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 231-238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By J Watt

The Hidden Valley Gold Project is located in a remote and mountainous area of the Morobe Province approximately 30 km south of the township of Bulolo and approximately 90 km south-southwest of the provincial capital, Lae. The Hidden Valley deposit was discovered in 1984 with the nearby Hamata and Kaveroi deposits discovered in 1987 and 1992 respectively. Reserves (Harmony, 2009) at these three deposits are 42.1 million tonnes of ore containing approximately 2.9 million ounces of gold and 45 million ounces of silver. A further 5.4 million ounces of gold and 84 million ounces of silver are in the resources category. The process plant is designed to treat 4.2 million tonnes per year of gold/silver ore extracted by open cut mining methods. Ore is classified into three ore types according to oxidation state: oxide, transition and primary. The silver to gold grade ratio is high for the Hidden Valley and Kaveroi ores, generally in the range 15 - 20:1, and much lower for Hamata, typically 1 - 2:1: Primary ore is the dominant ore type at Hidden Valley with sulfur grades up to about two per cent sulfur. Oxide and transition ores are more prevalent at the Hamata deposit, but its primary ore has up to five per cent sulfur grades. Variable ore types, particularly in the initial years of operation, high silver to gold ratios and limited plant site area, due to the challenging terrain, present the main processing challenges for this project. This paper describes the operating strategies and process development for the main areas of this circuit, highlighting selections of processes and equipment that achieve cost effective, yet flexible solutions to the treatment of ores from these deposits.

Jan 1, 2009

The Takasima Coal Mines comprise four islands near the entrance to Nagasaki Harbour, and are owned and worked by the Mitsu Bishi Company.There are several unusual features in the occurrence and working of these coal seams, the steep angle of "dip," the numerous seams of good coal separated by hundreds of feet of sedimentary rocks, the extensive faulting of the strata, and the way in which the coal is won, when so little surface is available for works, and where there is the ever present danger of subsidence of the roof and consequent flooding of the workings by the ocean. The author trusts that short notes on these few points will be of interest to members.The Islands are named respectively Hasima (Extreme Island), Nakanosima (Middle Island), Takasima (High Island), and Yokosima, and are situated about one mile from the main land.

Jan 1, 1901

By B Broad

"Establishing ventilation in the early stages of a new mine is an essential step to achieve scheduled outcomes that ultimately drive the financial success of an operation. If the primary ventilation is not in place in time to support a contractorÆs work output, then the ore delivery is likely to be severely impacted. Options to increase ventilation in order to address shortfalls are limited. This in turn can lead to reduced revenue generation at a time when a mine is at its highest capital outlay. This can have implications for any company, but even more for an explorer moving to producer. The ventilation put in place to cover the start-up period is also unlikely to cover any extended or increased load required to meet schedule delays.The following paper examines two issues in relation to ventilation with a focus on small to medium projects where the company is establishing a mine using a mining contractor. The issues being: potential impacts on the contract and tender process when using a mining contractor key mine design considerations, such as æcrunch timeÆ, as they interact with ventilation achieving a successful ramp up.A recommendation is made for higher levels of detail around secondary ventilation leading up to the primary fan installation. The information should be included as part of the tendering process and preliminary project execution planning. Understanding the æcrunch timeÆ concept can lead to strategies, as well as back up plans, to minimise any negative impact.By understanding key risks around primary ventilation establishment for a new mine, detailed design work can be completed where it is needed most. Value is added by reducing uncertainty and a payback with better contract terms and a more robust ramp up plan. This will improve the economic return for the company and reduce the risk.CITATION:Broad, B, 2013. Contract considerations and other critical ventilation aspects in achieving a new mine ramp up, in Proceedings The Australian Mine Ventilation Conference, pp 207-214 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 1, 2013

A short account is given of the theory and practice of determining the true U3O8 content of ore samples by the determination of the beta and gamma activities separately, using the method of Eichholz and his associates.It is shown that, despite the variation of sample activity without change in U3O8 content, the true U3O8 value can still be found.Thorium can be determined simultaneously if this element is also present.

Jan 1, 1957

By E Thomas, L McCallum, G Dale, J Bennett, K Reardon-Smith, S Raine

Sustainable closure of coal mines in Australia to a safe, stable, non-polluting condition remains one of the industry’s biggest environmental and social challenges. A significant proportion of mines in the Bowen Basin of Queensland have dispersive spoil. Based on an estimated area of 20,000ha and a rehabilitation cost of AUD$100,000 to AUD$150,000/ha, the instantaneous rehabilitation liability for the Bowen Basin alone is estimated at AUD$2 to $3 billion.Dispersive spoils present problems in post-mining rehabilitated landforms due to increased potential for surface and tunnel erosion, compromising the ability to achieve fundamental mine closure objectives of a safe, stable, non-polluting and self-sustaining post-mining landform (Minserve, 2004). Dispersion results in clay particles being mobilised and transported in water, even at low flow velocities (So et al., 1998; Minserve, 2004), and blocking of soil pores, resulting in surface sealing, crusting and reduced permeability (DNR, 1997; Vacher et al., 2004) which, in turn, further increases runoff (Dang et al., 2018).CITATION:Dale, G, Reardon-Smith, K, Thomas, E, Bennett, J, McCallum, L and Raine, S, 2018. A process-based approach to mine rehabilitation decision making using Bayesian modelling and risk-based principles for dispersive spoil rehabilitation, in Proceedings Life-of-Mine 2018, pp 106–109 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

How the Australasian and Canadian Codes (VALMIN and CIMVal) approach mineral property valuation is described. Brief comment is also made on the International Valuation Standards CommitteeÆs interest in a global valuation standard for Mineral (Extractive) Industries and the South African SAMREC initiatives to adopt a VALMIN-like Code. The conventional tripartite classification of valuation approaches into those that are Market-based, Income-based and Cost-based is outlined. It is best practice to use as many of these approaches as possible (and as many methods as reasonable in the particular circumstances), given the quantity and quality of the data available on the Mineral Asset (which depends upon the state of development of the mineral property). The use of specific methods must satisfy the basic considerations of logic and reasonableness and the purpose of the valuation. The competence, judgement and repute of the valuer are critical factors, since all valuations are time and circumstance specific. What constitutes æMarket ValueÆ in the different jurisdictions is discussed and definitions are given. Challenges facing the globalisation of a VALMIN-type Code for the international Minerals Industry are the influence of real estate valuers and the US jurisdictional idiosyncrasies. This is mainly due to a fixation on real property rights with a preference for using real estate-like comparative sales techniques (Market Approach) to the exclusion of Income-based approaches; a regulatory reluctance in the US to accept that Resources have considerable value; and the International Accounting Standards BoardÆs preference for Historical, rather than Current Value, accounting.

Jan 1, 2002

An understanding of the origin of mineral deposits and their relationship to local and global geotectonics is essential if regional targets for mineral exploration are to be chosen. Volcanism, metamorphism and tectonism are especially significant for the origin and emplacement of mineral deposits, which, far from being fortuitous oddities of nature, occupy well defined positions within distinctive lithofacies. Thus, suggestions for mineral exploration targets can be made taking into consideration the position of 'fossil' convergent and divergent plate tectonic boundaries to indicate areas of specific types of mineralisation. To be borne in mind, though, that level of exposure, time and location of magma generation are all additional and important controlling factors. To further understand the importance of the above parameters, one must refer to the concept of paired metamorphic belts (Miyashiro 1973) which develop during an orognic cycle. These belts are generally constructed in such a way that an ophiolite type complex with metamorphic grades related to high pressure and moderate temperature regimes is flanked by an area of calc-alkaline volcanism and granitic activity with metamorphic grades within a region of high temperature and low pressure. The former situation is usually the seat of primary magmatic mineralisation, whereas the latter contains base metal. Deposits of acid plutonic and volcanic association. As will be seen later, this particular metamorphic-volcano-orogenic situation is well developed in some parts of New Zealand. For the present purpose a distribution of potential ores as related to plate tectonic processes is given below:a) Divergent plate boundaries: primary magmatic Ni-Cu, Pt,Cr, PeS2 and Cu, Pb,Zn in hot brines-hydrothermal environments Mn deposits.b) Convergent plate boundaries: stratabound Cu-Fb-Zn-Ag of felsic volcanogenic association. Porphyry eu-Au of island arc type, porphyry Cu-Mo of continental type. Cu, Au, Y, Sn, Hg, Sb of vein type and replacement lode related to granitic activity.c) Au of hydrothermal vein association, related to late dynamo-metamorphic events. By virtue of ocean floor spreading, regions of divergent plate boundaries are eventually juxtaposed or welded n to areas where plate collisions occur. This is then followed by partial melting due to various causes, just above the descending plate; thus creating a zone of acid to intermediate magmatism. The final picture is that of an orogenic zone with the paired metamorphic belts outlined above.

Jan 1, 1976

By Sano S, Ishikawa T, Nagaoka H, Hayashi Y, Hasegawa M

The stirred mill is regarded as one of the most efficient devices for micronising materials and has come to be actively used for preparation of fine particles. Recently, the demand for ultrafine particles was increased in many kinds of industries. In this paper, autogenous grinding to get submicron particles based on mutual friction feed material has been carried out using a stirred mill. The mill used was made of stainless steel and its volume was about 5.5 litres, and has 12 impeller blades. Sample used was limestone. In the present work, two operating parameters such as stirring speed and feed size of limestone were considered. The ground products were sieved in the size range from feed size to 325 mesh (45 lun), and from 45 to 0.17 pm the size distributions were measured by a laser diffraction and scattering method. The progress of grinding was evaluated by the increasing amount of submicron particles in products. As a result, the rotational speed of impeller with the minimum energy consumption to produce submicron particles was observed. It was found that the autogenous grinding with a stirred mill is an effective method for producing submicronized limestone.

Jan 1, 1993

Chelopech Mining EAD and Best Available Techniques for Management of Waste Rock in Mining Activities

Sep 13, 2010

By R Stefansen, T Wisdom, A Nicholson, K Rahal

The challenges of increasingly scarce water resources and the risk of dam failures has seen the mining industry turn to sustainable tailings management solutions such as dewatering and dry stacking. Filtering tailings has been seen in the past as a cost-prohibitive process for larger throughput mines. However, as larger pressure filters are developed, the economic case for filtered tailings has gained traction.Focus has largely been placed on the correct design and operation of the filters. It is critical, however, that the material handling portion of the disposal system is also properly designed and operated. Thorough testing at laboratory and pilot scale to determine the conveying properties of the filtered material needs to be conducted. This testing will insure the material handling system meets the important availability needs of the mine even during periods of variability in the upstream processes and mine plan.The control system must also be robust and flexible in design to compensate for this upstream process variability. The control system needs to allow for different flowsheets including straight filtered tails as well as EcoTails™, a low-energy solution for co-mingling waste rock and filter cake.This paper will present case studies of different material handling solutions, the testing required for them and the lessons learned from each.CITATION:Rahal, K, Nicholson, A, Stefansen, R and Wisdom, T, 2018. Material handling testing and control system requirements for dry stack tailings, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By Z-Y Pi, B Zhang, S Wen

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

Aug 21, 2012

The aim of all modelling is to replicate geological reality as closely as possible using available data. This paper is aimed at one end of the spectrum, where very limited data is combined with intuitive geological ideas to synthesise models for either target definition or for determining minimum viable mining scenarios. Interactive 3D modelling allows a satisfactory hypothetical geometry of surfaces to be assembled, and provides a fast quantitative method for generating targets. As data flows from exploration, an evolving geological model assists with the progressive evaluation of a prospect. Two case histories are described where this approach has been used successfully, the Mosquito Hill Prospect in Queensland and the Longwood Ranges Platinum Prospect in New Zealand. The possibility is also discussed of hypothetically modelling an orebody which has yet to be discovered. The proper description of an orebody is the foundation upon which all mine design and planning is undertaken. The volumetric accuracy of the model is crucial in valuing an orebody. Geologists must form a geometry which matches the conceptual view of the ore occurrence and ensure that they understand how the computer system used calculates volumes. If the underlying assumptions inherent in the method conflict in any way with the conceptual model visualised for the ore occurrence, then that method must not be used.

Jan 1, 1995

The Waimumu area, 12 km southwest of Gore, is underlain by the Gore Lignite Measures, an early Tertiary fluvial sequence approximately 500 m thick resting on Triassic-Jurassic argillitic basement. The Waimumu Quartz Gravels (Pliocene) have been deposited locally and are in part due to the localised reworking of the Gore Lignite Measures. Structurally the area is dominated by the Dunsdale Fault System, a steeply dipping series of NE trending reverse faults (Isaac and Lindqvist, 1990). The Belle-Brook, Hedgehope and Parker Road sites sampled are adjacent to the downthrown (east) side of the Hedgehope Fault.The authigenic gold-sulphide association at Belle-Brook was discovered in 1987 (Falconer, 1987: Clough and Craw, 1989). Despite a very limited amount of alluvial mining a significant quantity of authigenic marcasite has developed. Authigenic sulphide trace element analysis has shown anomalous amounts of As, Ni, Cr and to a lesser extent Zn, Pb and eu (Table 1). It has been established that the nickel occurs as a colloform banded Ni sulphide, possibly bravoite, within the marcasite (Figures 1 & 2). Arsenic and nickel (re)mobilisation are well documented in the literature. Generally As and heavy metals are mobilised in the groundwater as a result of the oxidation of sulphides (ie as a result of mining). At Belle-Brook it is reasonable to assume the authigenic sulphide trace element composition reflects either localised groundwater contamination or hydrothermal mineralisation. This poster presents some preliminary findings.

Jan 1, 2001

Retreating Cu-Mo Rougher Tailing by Flotation for Concentration of Copper and Molybdenum

Sep 13, 2010

Prefeasibility planning and cost estimation of conveyor systems has historically been undertaken by comparing fi xed plant transport requirements to that of similar systems in service. This paper describes the development of a prefeasibility conveyor technical design and cost estimation application using Microsoft Excel Visual Basic for Applications (VBA) platform. The application tool known as D-Convey (Dachshund Convey) was developed with the goal enabling the end user: to develop a technical model for conceptualised conveyor systems, to perform economic analysis on the developed technical model, and to conduct a comparative and risk analysis. An Excel VBA based platform was utilised to draw upon both the analytical and graphical capabilities of a spreadsheet. Some of the features of D-Convey system include a revolutionary dynamic graphical help system, known as the 'information pane' in lieu of traditional help fi les as well as the use of familiar graphical user interface elements such as the MS Offi ce 2007 task ribbon. The D-Convey system incorporates material database allowing for mass handling prefeasibility estimation in other industries; it has been validated at a local quarry.

Dec 6, 2010

By F C. D Michelin

As mines get deeper, the critical underground temperature limits will be exceeded, and an increasing number of mines will need to implement, expand or modify cooling systems. Surface cooling plants have many advantages over underground cooling such as efficient heat rejection, and lower relative capital cost; however the delivery of cooling through long underground distances can result in lost refrigeration capacity before the chilled air reaches the areas it is needed most. Refrigeration plants are therefore often overdesigned in size and capacity to compensate for underground losses.More mines are now utilising real-time monitoring and automated control of ventilation airflow and fan systems to ensure the conditions underground are safe and productive, and power consumption is efficiently managed. There may be significant opportunities to extend ventilation monitoring and control into the refrigeration delivery and control system.Energy reduction is an effective way to reduce costs and CO2 emissions, which is an increasingly important part of corporate governance. More efficient refrigeration control is a further step toward reducing energy consumption. This paper looks at an added step in how real-time monitoring can assist in controlling the output and chilled air delivery of a cooling plant. The requirements, implementation, benefits and challenges will be discussed.

Oct 12, 2022

By J J. Moreno, J Willis, P Garvey

Many of the tailings storage facilities (TSFs) in Australia are upstream raised facilities for which the consolidation of the hydraulically deposited tailings is essential to the stability of the TSF. While much operational consideration is given to limiting the rate of rise of TSFs through careful management of deposition rates to achieve desired consolidation, the rate of embankment raise construction (RoC) is often not given the same level of consideration. Loading the tailings at too high a rate during construction could lead to upstream and potentially downstream failure of the embankment. The Tailings Retention System (TRS) at the BHP Olympic Dam Mine comprises upstream raised TSFs that are continually raised with a zoned embankment. Improving on 20 years of successful embankment raising, there was a desire to understand the acceptable RoC under varying operating conditions and assess upper construction limits to improve operational risk management. To understand the RoC, trial embankment raise construction pads were constructed at different rates and the pore pressure response of the underlying tailings material was monitored. The pore pressure data were used to calibrate the permeability and consolidation characteristics of the tailings in a finite element model (FEM) that replicated a typical embankment raise. The rate of material placement, location of the phreatic surface and construction load were varied in the FEM until failure was initiated. The results were presented as a period (in days) over which the various zones for the embankment raise could be safely constructed. The results indicate direct sensitivity to the depth to the phreatic surface prior to commencement of an embankment raise, as well as the point of application of the construction traffic load. This paper presents the study approach, challenges experienced in modelling the construction methodology, the study results and their relevance in the improvement of understanding of RoC at the BHP Olympic Dam TRS.

Jul 1, 2021

By S Phinn, V Glenn, P McKenna, P D. Erskine, D Doley

The key goals for mine site rehabilitation require mine managers to demonstrate that rehabilitation is safe, stable, self-sustainable and non-polluting. Within this context, it is reasonable for stakeholders to expect that mine site rehabilitation is resilient to disturbance impacts such as fire and drought. However, mine managers actively avoid fire on rehabilitation; and as a result have limited understanding of fire behaviour on revegetated landforms, the long term implications for site stability and the potential risk to site relinquishment. An experimental fire that was conducted at the Curragh Mine site in May 2015, burnt 117 ha of 19- to 21-year old mine site rehabilitation, mimicking wildfire conditions and creating a mosaic of fire impacts across the landform. Using a combination of ground surveys and remote sensing assessments, we demonstrate that over a two year period, ecological metrics such as species richness, woody density and understorey biomass all recover to pre-fire levels for both grassland and open woodland areas. This is supported by WorldView-3 satellite imagery and the remote sensing assessment using the differenced Normalised Differenced Vegetation Index (dNDVI) which shows high regrowth within the burn area in 12- and 24-month image captures. The results suggest that within the recorded conditions, this site is resilient to fire impacts, and has the capacity to recover to pre-fire levels within the first two years following the fire.CITATION:McKenna, P, Erskine, P D, Phinn, S, Glenn, V and Doley, D, 2018. Measuring the recovery of coal mine rehabilitation following fire in Queensland using remote sensing and ground surveys, in Proceedings Life-of-Mine 2018, pp 141–146 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

A predicted increase in aluminium production and the possibility of a diminishing supply of petroleum coke for anode electrodes in alumina reduction cells makes it desirable to find alternative electrode materials. Browncoal char, with a lower ash content and with an elemental purity similar to petroleum coke, was produced by leaching in hydrochloric acid, washing with water, and charring at 1,150°C. The cost of processing is estimated tobe competitive with petroleum coke.Without further processing the bulk density and real density were undesirably low, but by briquetting the coal before charring and crushing, the bulk density was improved to 92 per cent of the petroleum coke value andthe particle density was improved to 92 per cent of the density of petroleum coke by water displacement or 75 per cent by mercury displacement.Pre-baked electrodes were prepared from the char alone, mixtures of petroleum coke and char, and from petroleum coke alone, all bonded with coal tar pitch.The electrodes were tested for the usual physical properties and were evaluated for performance in a laboratory size alumina reduction cell.Electrodes based on brown coal char alone were found to be inferior in physical properties and performance, but mixtures of the char and petroleum coke, despite poorer density, electrical resistivity, and carbon consumptionon a theoretical basis, in performance tests gave up to 17 per cent better carbon consumption per weight of aluminium produced and 21 per cent better electrical current efficiency than the electrodes based on petroleum,coke alone.It is suggested that larger scale tests are warranted.

Jan 1, 1971