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A four monthly period was analysed for each retreating longwall face which indicated that output increased from 1140 tonnes/day for Longwall 1, to 1620 tonnes/day for Longwall 2 and to 2090 tonnes/day for Longwall 3. An output of 2500 tonnes/day should be achieved from the new Longwall 4, largely due to the improved tailgate corner design and despite a continuing lump coal problem. The evolutionary trend is a feature of longwall mining; the evolution occurring both with mining and mechanical design at the colliery itself and with the longwall equipment offered by manufacturers. The trend is towards simplicity, increased strength and capacity, simplified maintenance and increase relia- bility.

Jan 1, 1976

By P J. Clark, A W. Fisher, R G. Ford

Site characterisation of subsurface contaminant transport is often hampered by a lack of knowledge of site heterogeneity and temporal variations in hydrogeochemistry. The use of a regional-scale data compilation derived from satellite imaging is discussed with respect to directing design of site characterisation to monitor the fate of a Dense Non-Aqueous Phase Liquid (DNAPL) plume in Nevada. Evaluation of the drainage basin contributing to the groundwater flux into the study site was used to re-assess the site conceptual model and re-direct the characterisation effort. The use of highly resolved measurements of subsurface hydrogeochemistry in space and time were employed to identify the predominant biogeochemical processes controlling arsenic transport during discharge of groundwater into a pond at a site in Massachusetts. Direct-push conductivity measurements coupled with vertically-resolved sampling within the pond and adjoining aquifer demonstrated spatial and temporal variations in dissolved arsenic within groundwater and the pond water column and sediment pore water. Spatial variability was observed over the scale of centimetres to metres, and temporal variations were observed over the scales of days (following storm events) to seasons. Microbially-driven redox processes maintained anoxic conditions in groundwater and at the sediment-water interface (iron and sulfate reduction) and exerted both a direct and indirect influence on arsenic solution speciation and partitioning to surface water sediments.

Jan 1, 2004

By Mitchell D

In recent years the need to provide increased ventilation to improve environmental conditions rather than to dilute firedamp has led to increasing interest in the use of recirculation. Present UK mining law prohibits recirculation in ventilation, but it has been permitted selectively by exemption granted by Hm Inspectorate of Mines and Quarries. The conditions of use imposed by these exemptions to safeguard the safety and health of miners are examined in detail, dealing separately with primary and auxiliary recirculation systems.

Jan 1, 1988

The transition from low stress to high stress conditions is a challenge eventually faced by most mines in Australia that extend to depths greater than (generally) about 1000 m. In areas with strongly adverse 'stress versus depth' gradients, such as some parts of Western Australia, significant stress-related problems have occurred at depths as shallow as 300 m below surface. The actual depth at which the 'transition' occurs is a function of the local pre-mining stress field, the strengths of the various rock types hosting the deposit and the layout and sequencing adopted in the mine. Stress-related damage can result in increased support costs, and delays associated with rehabilitation and disruption to production. In the worst case, where strong seismicity and associated damage occurs in active mining areas, 'exclusion' zones and 're-entry' protocols may be required. These can severely disrupt production. A key aspect of managing the transition is the recognition of the onset of stress-related ground behaviour. Damage mapping can be used to develop understanding of the relationships between mining activities and the local and regional response to them. Carefully documented case histories provide a basis for calibrating numerical models. This paper discusses some of the typical styles of ground behaviour observed in higher stress conditions in underground mines. A simple damage classification scheme is described to assist in 'damage mapping' of mine tunnels. An example of damage mapping is presented to illustrate an approach commonly used for recording stress-related damage.

Nov 25, 2010

By P Dowd, R Jeuken, C Xu

In Australian coalmines there are a number of coal quality parameters that are measured by analysing samples from boreholes. The data points are used to generate spatial models of these parameters, typically using inverse distance as an interpolation method. Numerous additional boreholes are drilled which have geophysical logs measured downhole but from which no coal quality samples are taken. Full suites of coal quality analyses are expensive and time consuming to drill and sample. If geophysical proxies for coal quality could be used, this would greatly improve the accuracy of the resource estimation without additional cost.This paper examines two of the most important coal quality parameters – ash and volatile matter – and assesses the results of a number of geostatistical interpolation methods. The aim is to improve the accuracy of the interpolated models. Auxiliary variables from geophysical logs are also trialled to improve the estimation.A multivariate analysis of ash, volatile matter and several auxiliary variables of a selected coal seam was undertaken in a spatial context, using variography. This was used to construct a model of co-regionalisation that relates all of the variables as manifestations of an underlying geological theme.The traditional inverse distance interpolation approach was compared to ordinary kriging, universal kriging, co-kriging, regression kriging and kriging with external drift approaches. The relative merits of the six interpolation methods were compared by removing all points, one at a time and estimating at the thus known location. The mean error and the root mean square error were evaluated as a measure of bias and precision.This paper demonstrates that there is significant opportunity to improve the estimations of coal quality when using kriging with external drift. For example, the results show that when using the depth of a sample as an external drift variable there is a significant improvement in the accuracy of estimation for volatile matter. Furthermore, when using borehole wireline density logs as an auxiliary variable for ash content, there is improvement in the estimation of the in situ ash. The underpinning reasons for this are discussed in the context of the underlying geology and the physical properties of the coal. These findings hold promise for utilising cheaper proxies for coal quality parameters to dramatically improve data density and the quality of estimations.CITATION:Jeuken, R, Xu, C and Dowd, P, 2017. Improving coal quality estimations using geostatistics and auxiliary variables, in Proceedings Tenth International Mining Geology Conference 2017, pp 157–168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By J Franz, S Bock, N Hentrich

Artificial ground freezing is the unrivalled method for groundwater control during mine shaft sinking. Moreover, ground freezing may also provide temporary ground support. The fast development of fibre-optic temperature monitoring devices, three-dimensional freeze pipe survey methods and numerical modelling software provide grounds for developing new and reliable tools for ground control during freeze shaft sinking. This paper presents examples of predictive numerical models that are based on back-analysis and calibration of temperature data that covers the complete construction cycle from pre-freezing through to artificial thawing. The back-analyses showed that standard numerical models are not capable of predicting the prevailing thermo-mechanical conditions satisfactorily. This paper describes the development and implementation of new tools for improved consideration of concrete hydration and latent heat, along with the introduction of other algorithms that improve and simplify the efforts of managing complex numerical models. A function is presented that allows for an automated correction of the model’s mesh based on results of three-dimensional freeze pipe surveys. This paper demonstrates that the latter consideration is important, because the often employed assumption of idealised freeze circle geometry in numerical models impacts on the accuracy of such model’s predictions. Subsequently, the verification of these extended numerical models is demonstrated. Due to its flexibility, the FLAC3DTM code was employed for the numerical modelling. This software provides the possibility of implementing additional functions written in internal FISH or Python language into the models. It is concluded that state-of-the-art techniques for freeze hole drilling and surveying, on-site monitoring and advanced numerical analysis provide a significant potential for both the design and the operation of largescale ground freezing measures. The application of the extended numerical models for predictive simulations during construction allows for temporary shaft lining optimisation, for assisting in operational decision making and for compensating temporary loss of monitoring data. Suggestions are made for required future work in order to further improve the developed ground control tools. CITATION:Bock, S, Franz, J and Hentrich, N, 2018. New tools for ground control in freeze shaft sinking, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 393–406 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By K W. Mills, N R. P Baczynski, J Mylvaganam, D A. Prado, M F. Lee, I A. de Bruyn

"This paper presents the second part of a study of the assessment of rock stress inputs on the performance of various new mining designs at the Ok Tedi large open pit mine in Papua New Guinea. Over the years, four programs of rock stress measurement have been completed at Ok Tedi, each providing different interpretations of the in situ field stresses. Details of three of these programs and interpretations are provided in the precursor to this paper, entitled ‘Rock Stresses at Ok Tedi, Papua New Guinea’ (Lee et al, 2014).This paper explains how the various stress interpretations were utilised in the modelling of the proposed new open pit and underground mining excavations, comparing where possible their expected effects on stability. The modelled performance of three specific mine components have been discussed here as case studies, including: the below-pit drainage tunnel, as the floor of the open pit workings is mined down from 350?m above, to within just 75?m above the crown of the tunnel the stability of the 1000?m high slope of the proposed West Wall cutback the proposed sublevel open stoping extraction sequence in the Gold Coast orebody beneath the East Wall, for which only the likely ‘worst-case’ stress regime was used to assess sequencing and stability issues.The benefits of scheduling the collection of detailed rock stress measurements and other input data from a range of different sources at various stages of the projects are discussed.Alternative in situ stress models have less stability impact on open pit slopes than on underground mine excavations.CITATION:de Bruyn, I A, Baczynski, N R P, Lee, M F, Mills, K W, Mylvaganam, J, and Prado, D A, 2014. The application of rock stress inputs to stability assessments at Ok Tedi Mine, Papua New Guinea, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By A Hacket, M Haest, I Vitins

Infrared spectroscopy has the ability to accurately measure mineralogy of drill cores, allowing for better spatial characterisation of iron ore deposits and potentially improving the prediction of key mining and processing parameters at the deposit scale. BHP Billiton Iron Ore is using infrared spectroscopic drill core logging to provide fast and accurate mineralogy for diamond cores and reverse circulation (RC) samples.Mineralogy can be predicted from infrared spectroscopic drill core data with errors on estimates ranging from six to 12 weight per cent. The error on the clay estimates is significantly lower than for hematite and goethite content estimates. This manuscript presents the results from a study on a bedded iron ore deposit, hosted in the Brockman iron formation, for which infrared spectroscopic data were collected on all of the diamond and RC drilling. Results show that these mineralogy estimates improve drill core logs, the geology model and the metallurgical block model.CITATION:Haest, M, Vitins, I and Hacket, A, 2013. Infrared spectroscopic drill core logging - making inroads to deposit scale 3D mineralogy, in Proceedings Iron Ore 2013 , pp 251-258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The basic flowsheet for the Kalgoorlie Nickel Smelter and Kwinana Nickel Refinery are discussed in relation to the mineral components of Kambalda produced nickel concentrates. Both processes handle violarite and pentlandite satisfactorily but the smelter has limitations where high copper recovery is required and in its ability to handle magnesia containing minerals. While the latter can be more economically handled at Kwinana the limitations of this tolerance are discussed together with problems arising from treating pyrrhotite, pyrite and precious metals by the Sherritt Gordon process.

Jan 1, 1973

Formed in 1965 to investigate the bauxite deposits on the Gove Peninsula, in the Northern Territory of Australia, Nabalco Pty. Limited undertook to determine the feasibility of establishing a mining operation and alumina plant of at least 500 000 tonne/year capacity. The drilling programme undertaken and the analytical methods, assumptions and criteria used to define practicably extractable bauxite are described. The ore characteristics and the interpretation of results used to evaluate the reserves are detailed. The operating techniques developed in mining ten per cent of the reserves and variations experienced between indicated and actual mining are examined and discussed.

Jan 1, 1979

By M Fylak, R Wenda

Advanced preparation techniques open new ways for SEM and X-ray diffraction (XRD) investigations on hydrating cementitious systems. In this paper the early time hydration of Portland cement is studied with advanced cryo scanning electron microscopy techniques in combination with in situ X-ray diffraction and heat-flow calorimetry. The application of preparation techniques and analytical methods to Portland cement hydration are presented and discussed. Some aspects of hydration reactions are focused. The reaction products of the first minutes, changes in ettringite morphology, AFm formation during the deceleration period and the visualisation of C-S-H microstructures were special points of interest. X-ray diffraction analyses and Cryo-SEM images gave essential information about phase development, reaction kinetics, microstructure and morphology of hydration products. Portlandite, AFt and AFm phases were detected by in situ XRD. Cryo-SEM analyses enabled high resolution imaging and EDX-analyses of cement particles and reaction products. The results of the different analytical methods were compared to obtain detailed information about crystallisation processes and microstructural development during the first three days of Portland cement hydration.

Jan 1, 2008

The construction of mine headframes of reinforced concrete is not a new departure as many structures have been built of this, material particularly in Canada and South Africa. This type of construction has been satisfactorily tested in service and is now accepted by the mining fraternity.The two headframes at New Broken Hill Consolidated Limited are the first structures of this type to be built in Australia, and provide an interesting application of reinforced concrete design and construction.Reasons for Adoption of ConcreteDuring 1947 the writer visited D.S.A. and Canada and inspected three headframes, of reinforced concrete construction.Leading details are as follows:(i) Hollinger Gold Mines. (Timmins, Ontario) : Height of sheaves 110 ft. Shaft has provision for 4 skips each of 12,000 lb. capacity. Structure incorporates surface crushing plant.(ii) International Nickel Corporation-Murray Shaft (Sudbury): Height to sheaves 153 ft. 6 in. Shaft provides for 2-12 ton skips and 2 cages. Surface crushing plant built integrally with frame.(iii) Asbestos-Johns Manviae (Quebec): Height of sheaves 116 ft. Shaft provides for 2 skips 200 cu. ft.

Jan 1, 1956

By B Howard, M Jones, D Pershke

"Current closure objectives and criteria are often difficult to achieve and are not delivering value for money outcomes at closure. Current mine closure processes tend to focus on rehabilitation and revegetation of landform structures to as close to premining condition as possible, rather than focusing on the functions of those structures and values they provided. Because mining has highly disturbed the environment, premining conditions and vegetation are often not achievable and objectives and criteria aimed at achieving close to these conditions have been shown to be very costly.The authors have developed a broader approach to developing mine closure plans that is based on environmental risk and gaining post-closure social, environmental and economic value. We think the focus should shift from trying to return the original landscape to returning functions and values provided on- and off-site. If it is not possible to return values on-site in a cost-effective manner, investment should be provided to deliver equivalent values elsewhere.This process can provide better stakeholder acceptance, deliver better environmental outcomes on the tenement and within the catchment and significantly reduce costs, whist fulfilling closure obligations.This framework should enable closure teams to: focus on the functions and services that are important to achieve as outcomes post-closure, rather than a focus on revegetation and replacing the premining biophysical structure engage meaningfully with stakeholders regarding closure outcomes and link outcomes to stakeholder values conduct transparent option evaluations that enable stakeholders to clearly understand the costs and benefits associated with each option and to participate in dialogue on option selection.We present examples of how the framework could be applied to identify alternate closure options that achieve equivalent value outcomes while reducing the costs of closing the mines.CITATION:Howard, B, Pershke, D and Jones, M, 2014. Achieving better mine closure outcomes for less money, in Proceedings Life-of-Mine 2014, pp 615–620 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 16, 2014

By M Gerards, M Steinberg, T Graham

The quality and quantity of Australia’s secondary deposits, which include tailings streams and tailings dams, are higher than most countries’ primary deposits. In addition, these secondary deposits have already been mined and processed, meaning that the recovery of high-grade product requires low capital and operating costs.The most widely used process for the recovery of these valuable fine and ultra-fine hematite iron particles is the wet high-intensity magnetic separation technique, originally developed by Dr Jones over 55 years ago. Many of the original machines are still working today.The aim of this paper is to demonstrate the capabilities in terms of grade and yield of using sophisticated magnetic separation modules. All results and figures are obtained from test work and design and engineering work with material from the Pilbara. In addition, consideration is given to dewatering of iron ore product and tailings.Two types of tailings have been identified for processing. Firstly, tailings that have already been deposited in a tailings storage facility, and secondly, live tailings streams from an existing wet iron ore beneficiation plant. In both cases, the technical and practical results are shown along with relevant flow sheets and plant layouts. Finally, this paper highlights the total predicted power and water consumption, capital requirements and projected operating expenses.The results show that the operating costs are significantly lower than the mining and processing operations that are required for an equivalent amount of iron ore. The recovery of iron depends on various factors but is within the 30–50 per cent range at an equivalent grade to the mainstream product. Another significant benefit is that the magnetic separation process is water positive, meaning that water is released rather than added in the process.The processing of the Pilbara’s secondary deposits will therefore result in an overall reduction in operating costs, an increase in product yield from a plant, extend the life-of-mine and offer environmental benefits by reducing the tailings footprint and water usage.The quality and quantity of Australia’s secondary iron ore deposits and tailings are such that many other countries would judge these as equivalent to primary deposits. Furthermore, these tailings are already mined, available and liberated to such an extent that the recovery of a valuable product is highly economical in terms of capital expenses and operating expenses.CITATION:Steinberg, M, Graham, T and Gerards, M, 2015. Recovery of iron ore fines and ultrafines from tailings by using wet high-intensity magnetic separation – JONES WHIMS, in Proceedings Iron Ore 2015, pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By M Medina, J Alexander, R J. Longey

Capricorn Copper Pty Ltd (CCPL) are operating the Capricorn Copper Mine located at Gunpowder, Queensland. As current holder of the environmental authority for the site, CCPL have obligations to rehabilitate areas of the mine that are no longer operational and have the potential to cause/contribute to environmental harm. CCPL sought a voluntary Transitional Environmental Program (TEP) to provide an agreed program of works to cap and rehabilitate the former Mammoth Tailings Storage Facility. The voluntary TEP contained conditions that were required to be met, to reduce the potential for environmental harm from the facility. The former Mammoth Tailings Storage Facility commenced use in the early 1970’s, and is an unlined valley in-fill structure, contemporary in design compared with other such approved structures of the era. The decommissioned Mammoth Tailings Storage Facility, now known as the Old Tailings Storage Facility (Old TSF), has been a legacy source of contamination due to the existing capping not meeting modern cover criterion, and allowing oxidisation and infiltration to the underlying acid forming tailings resulting in Acid and Metalliferous Drainage (AMD) from the facility. A cover design for the Old TSF, and other mine waste storages onsite that required clay capping, had been proposed by previous operators. Under the TEP cover design phase, it was identified that a key constraint was the lack of significant quantities of low permeability clay onsite. The lack of available clay prompted the consideration of alternate lining materials for the Old TSF, with a Bituminous Geomembrane Liner (BGM) being adopted as the preferred alternative. The BGM compared favourably with clay-based materials on seepage analysis, and led to other benefits by eliminating the need for borrowing clay off site, reducing the site’s environmental footprint, and reducing construction time. The BGM cover system on the Old TSF is being monitored with the intent to use this as a case study to confirm expected performance, enabling the cover design to potentially be adopted on the remainder of the site’s mine waste storages that require capping.

Jul 1, 2021

A survey of leaching systems for the dissolution of gold has been undertaken and their advantages and disadvantages evaluated both from their effectiveness at leaching and their compatibility with carbon- in-pulp (CIP) and resin-in-pulp recovery. In the near future it is almost certain that cyanidation in some form will remain the leaching system of.choice although economic and environmental pressures could see the introduction of other leaching systems particularly for treating refractory gold ores. The most likely alternative leaching systems appear to be acid chlorine, acid thiourea and ammoniacal thiosulphate. INTRODUCTION High grade reserves of readily recoverable gold ores are gradually being depleted which, inevitably, must create a greater awareness amongst gold producers, of the efficiency and, in some cases, the suitability of present day metallurgical processes for treating low grade, complex and refractory deposits. One of the key steps in the extraction of gold is the dissolution of the metal using chemical reagents which, ideally, should be cheap or recyclable, selective, non-toxic and compatible with down-stream recovery processes. In practice, meeting all these critera is difficult - if not impossible - particularly in view of the stringent environmental impact requirements which must be met Nowadays.

Jan 1, 1982

Mixers are commonly used for the transfer of oxygen in gas-liquid-solid reactions in minerals processing. The process rate is usually controlled by two steps: gas-liquid mass transfer and reaction kinetics. Some examples are described along with the factors used for analysis of the mass transfer design problem. Typical oxygen rates and appropriate types of aeration systems or mixers are reviewed. The commonly used Rushton turbine has limitations in a number of mineral processes. The development and characteristics of the LIGHTNIN A315 axial flow gas dispersion impeller are described. Some practical examples which highlight its advantages are briefly described.

Jan 1, 1992

Quite often the reserve assessor becomes enamored with the numbers gen- erated and forgets the basis for his assessment. The quality of the assess- ment can only be as good as the quality of the input data. The use of seismic data from the Gippsland Basin in assess- ing Esso/BHP's oil and gas reserves is an excellent example of this principle. By significantly improving the quality of seismic data, a much more reliable estimate of a field's reserve potential can be made. In addition, it provides the basis for further delineation drill- ing which, as recent experience in Gippsland has shown, often leads to increased reserves.

Jan 1, 1979

By J J. L du Plessis

Escalating energy and electricity costs have become one of the biggest expenditure drivers in mining operations. During the last eight years, energy costs have trebled when expressed as a percentage of total running cost in South African mines. Power consumption on mines is controlled by three main strategies, namely load clipping where energy use is reduced for parts of the day, load shifting where energy use is shifted to other parts of the day, and energy efficiency where energy use is reduced permanently.To reduce the operating costs of ventilating and cooling underground mines continuously, system optimisation studies must be completed. A part of this paper describes methods that can be used to reduce energy usage by optimising cooling and ventilation systems during planning and in existing operations using network simulation models that accurately reflect the current and planned ventilation conditions. These models are used to examine various options for improving the overall ventilation and cooling efficiency. Furthermore, an overview of refrigeration and cooling practices, and ventilation strategies is presented.Ventilation-on-demand and cooling-on-demand strategies have the potential to reduce both the capital and operating costs associated with mine ventilation and cooling systems. In addition, it has been proven that modern strategies and energy-efficient tactics are technically feasible.It is also important that the correct equipment selection is made. This must be based on the best technology with the highest energy efficiency. Where equipment replacement is being considered, energy efficiency must be one of the key decision drivers.In this paper a number of studies were presented and from the experience and the data presented it is clear that a large financial benefit is possible through optimising ventilation and cooling during the planning of mines or within an existing operating mine.CITATION:du Plessis, J J L, 2015. Strategy and tactics implemented to achieve energy-efficient ventilation and cooling of mines, in Proceedings The Australian Mine Ventilation Conference, pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

Project-finance risk assessment is mature and approached systematically. Mining industry due diligence remains fragmented with specialists addressing different aspects of the project such as reserves/JORC, environmental impact, commodity market, even financial analysis/ modelling. Each professional has a natural tendency to believe that the risk factors they have examined are the key ones necessary to be reviewed, as if their review will stand in isolation from others in the way a project materialises. By first laying out the project risk categories and risk matrices, this paper examines the due diligence process with a keen eye to the risk assessment and overlap/interaction. Some cross fertilisation of due diligence techniques from other industry sectors is placed into the mining context. Six case studies are then presented with regards to due diligence features in each projectÆs feasibility review or financial information/ offering memorandum. A power case first shows the differences between the due diligence expectations of banks versus bond financings. Then some Australian and Indonesian mining development cases are analysed to see the due diligence learning points. Some of these were project/due diligence failures. The conclusion focuses on the value of a systematic risk assessment for project evaluation, all from the project-finance perspective.

Jan 1, 2007