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The desire for minimising impacts of mining activities on the environment, and in particular, water resources; is usually tempered by the costs and practicalities of implementing æbest practiceÆ measures. This paper briefly discusses the theoretical and practical options for water management for typical mines and quarries in a range of environments to assess if adverse impacts can be completely eliminated or at least be perceived as doing so. The regulatory requirements for water resources management are usually an essential part of mine planning and operations that can be a primary focus for all stakeholders. As such they can distract attention from implementing best practice in water management for the benefit of the environment and the community for altruistic reasons that have a long-term benefit for the mining industry as a whole. Cost-effective options for supply, demand and quality management of water that comply with basic regulatory requirements are readily available. Making a mine æinvisibleÆ in a practical sense, in terms of impacts on water resources would require eliminating potentially contaminated discharges, minimising demand, maximising reuse and recycling and putting back a healthy proportion of the clean water that is taken out of the natural environment for use in mine operations. This may sound simple enough and there are many well-known standard approaches that are usually applied. But which are the most effective, and who benefits? New approaches to water management are becoming more affordable and can benefit the bottom line as well as the environment, but can they make a mine ædisappearÆ? The perception of whether a mine is æinvisibleÆ in terms of its impacts on water resources is as important as the actions taken to try to achieve such an objective. The viewpoints and thresholds of perceptions of the different stakeholders are therefore relevant to how ævisibleÆ mining activities become.

Jan 1, 2006

This paper is essentially an address, rather than a detailed presentation of facts, because the third edition of `Nuclear Electricity - An Australian Perspective' has just been completed and will be available for the seminar. That 96-page booklet contains a lot more information than The AusIMM would be prepared to print in the seminar proceedings. Hence I have kept this paper brief, and ask readers to obtain a (free) copy of Nuclear Electricity at the seminar or from The AusIMM. It can be read as a supplement to the paper (or vice versa). According to one of Australia's well known critics of nuclear power, Professor Ian Lowe, `the pro-nuclear lobby's predictions of the future use of nuclear energy .... have been regularly and consistently wrong by large amounts, always overestimating the future demand for uranium" (Aust. Society, April 1989). While I do not accept this as a bald statement applying to all those in favour of increased use of nuclear power, there is sufficient truth in it for it to be credible. Certainly in the 1950s and the 1960s, when the new technology for producing controlled power from atomic fission was first being commercialised, there were some very exaggerated projections of the role of nuclear power. Many people thought that it would take over from fossil fuel fired electricity generation in much the same way as the motor vehicle took over from horse-drawn transport. And these early projections were not simply concerned with electric power generation, they included excavating harbours and digging canals with nuclear explosives.

Jan 1, 1989

By R Morrison, P Owen

Particle breakage is an essential part of mineral processing. The aim is to reduce run of mine mineral ore to an optimal size for liberating target minerals and for subsequent recovery by separation processes such as flotation. This size reduction is typically accomplished in a series of stages in a grinding circuit tailored to the properties of the particular mine ore. Commonly this involves two or more classes of equipment starting with crushers, followed by SAG mills and then sometimes ball mills. Occasionally, high pressure grinding rolls or other novel devices are substituted. Broadly, energy consumption increases and energy efficiency decreases with the fineness of the material produced by each piece of equipment. For many operations, up to 50 or 60 per cent of total greenhouse gas emissions from a plant arise from the operation of the comminution circuit with the majority produced by the finest grinding parts, such as the SAG and ball mills. Wear of mill liners and grinding media also add to greenhouse gas emissions generated by their manufacture. The need for continual cost reduction and increasing regulatory and social pressure relating to greenhouse emissions create a strong need for improvements in comminution energy efficiency. Traditional experimental and modelling approaches are not well placed to create the required insights into comminution fundamentals or facilitate radical step changes in performance. This paper discusses the role that advanced modelling (based on coupled DEM and CFD) can play in improving the energy efficiency and performance of existing mainstream grinding equipment and in the development of new ones with radically superior performance. Achieving this goal will also require an improved understanding of ore breakage and methods to include sufficiently realistic breakage models within the DEM models. Developmental issues for the modelling and the critical need for validation of the advanced model features are highlighted.

Jan 1, 2004

The classical view of island arc geology is that of a plutonic intrusive/volcanic extrusive complex, derived from the products of oceanic lithosphere subdu.ction and constructed on an over-riding plate of oceanic origin. Such an arc is typically backed by a marginal basin, formed by seafloor spreading of a more or less conventional kind. Various studies undertaken over the last decade have modified this picture and provided a new tectonic framework within which to explore for resources. Formation of Marginal Basins During the 1970s, seafloor spreading magnetic anomalies were identified in various marginal basins in the SW Pacific. In one of these, the South Fiji Basin, there was clear evidence of a ridge-ridge-ridge triple junction, although no kinematic relationship to the major plate boundaries was determined. Palaeomagnetic studies conducted in Vanuatu and Fiji, and in the Bismarck Archipelago of PNG provided evidence of large scale arc rotations relative to major plates. This indicated a general pattern of marginal basin formation by ridge-ridge-ridge triple junction growth together with island arc growth by trench-ridge-trench triple junction evolution. Formation of Primitive Island Arcs The triple junction growth model strongly suggests that at least a significant amount of arc evolution occurs by the initiation of subduction at a spreading ridge. This has predictive implications for the nature of island arc basement.

Jan 1, 1987

By B R. Olsson, N Marinopoulos

To establish the design and the capacity of the Stanwell Magnesium Plant, Australian Magnesium Corporation Ltd (AMC) with Fluor Australia has modelled the operation of the magnesium plant using ARENA Simulation Modelling. The reliability model has been used to evaluate: surge capacities required between different sections of the plant; critical equipment requiring standby capacity; the number of trains required for different sections of the plant; and potential capital cost reduction options. The reliability model was established using the detailed Process Flow Diagrams, reliability information from literature and maintenance, operation and start-up experience from the Demonstration Plant. The model was run with different plant configurations to assist AMC in determining the most effective configuration to provide the production capacity at the lowest capital cost. The model was not only able to confirm the plant capacity to the independent technical expert but was able to minimise quantitative risk by minimising the quantities of hazardous materials on site. Fluor Australia provided the ARENA simulation expertise and has used this software for optimising new plant design and to establish improvements in operating plants. Reliability modelling is a normal feature of chemical plant design but is rarely used in the resource industry. The experience gained by AMC in the modelling system has indicated that metallurgical plant design can be improved by the application of reliability modelling.

Jan 1, 2002

By G De Tomi, R Sousa, A Lapworth

One of the current challenges for iron ore producers is the ability to respond to changes in ROM stockpile specifications in a quick and cost-efficient manner. The decision-making process to respond to such changes is normally associated with grade-control and short-term mine planning activities, from where new operating instructions to the mine are provided. Mines are under increasing pressure from changes in the industry, such as a scarcity of skilled staff; a higher turnover of skilled employees and tighter product specifications. The quality of operational activities easily suffers as a result of these pressures. The technology that supports operational activities is often poorly implemented, which results in systems being unsustainable and poorly understood by the organisation. All successful technology implementations rely on the people, processes and technologies involved being well understood. Because of the complex nature of mining, the processes that underpin mine planning, scheduling and operational control are often not well defined. This results in activities undertaken by individual departments being poorly integrated. Datamine has developed a set of tools and methods for decomposing; capturing and documenting processes and ensuring those are embodied in implemented solutions. A case study of such a solution is the GEROS planning system, which has been successfully implemented at CVRDÆs Southern Iron Ore System, in Minas Gerais, Brazil.

Jan 1, 2005

By R Puglisi, G McPhail, B D. Jilbert

The increased international focus on sustainable development and cost improvement, coupled with the unpredictability and adverse impact of droughts in Australia and globally, has highlighted the critical need for responsible management of water within the minerals industry. The Rio Tinto Technology Group recently initiated a priority program to examine how water management practices could be improved within the GroupÆs spheres of activity. Rio Tinto Technical Services (TS), the technical services consulting group of the Technology Group, has for many years been undertaking water management reviews and assisting group operations with the development of responsible water management strategies and plans. Rio Tinto therefore requested that Rio Tinto Technical Services develop a world-class approach to mine water management that will drive improvement in strategic assurance and operational efficiency of water at the companyÆs managed operations across the world. The initiative, known as æExcellence in Water ManagementÆ, includes the selection and use of state-of-the-art management, technical tools and methodologies to strive for best practice. The Rio Tinto Technical Services approach facilitates a consistent and objective assessment of performance across the entire spectrum of complex water management issues within a mining operation, from initial exploration through to decommissioning and close-out of the operation. Based on this rigorous assessment, detailed action plans can be developed, prioritised and scheduled for subsequent implementation. This paper presents the progress and experience gained to date in the æExcellence in Water ManagementÆ program, demonstrated by means of a pilot study conducted at Northparkes Mines in New South Wales.

Jan 1, 2003

Evidence abounds for sea-level change having occurred throughout geological and recent time. Driven by climatic changes, by cycles of glaciation and deglaciations, and by tectonics the position of sea-level relative to the crust has been going up and down since oceans first formed. Rates of these differential movements have been as high as 10 mm/year during the last major deglaciation as sea-level rose by about 150 m in about 15000 years. Tectonic processes can also produce change in sea-level relative to the crust of several mm/year as in, for example, the uplift of the Huon Peninsula in Papua New Guinea. To understand what is happening to sea-level today and what may be happening in the future it is necessary to understand the geological and climatic processes that have caused sea-level to change in the past and the best laboratory for the study of these processes is the geological and geomorphological record. Evidence for observations of sea-level change throughout Late Pleistocene and Holocene time is plentiful in the Australian region. Temporal variability is characterized by a low-stand, at more than 100 m below the present level, at about 20 000-18 000 years ago followed by a rapid rise and transgression of the continental margin up to about 6000 years ago. After this time sea-levels remained within a few metres of their present value but the patterns of change are not everywhere the same. The depth of the low stand at about 18 000 years ago does not appear to have been the same everywhere. Nor does the time at which sea-level first reached its present value appear to have been everywhere the same. The fluctuations about present sea-level during the past 6000 years appear to have been different in different localities. As yet there has not been a wholly satisfactory quantitative explanation for this spatial variability. How much, if any, is indicative of vertical tectonics? How much is the result of the Earth's response to the changing surface loads as mass is exchanged between ice sheets and the oceans? Can any of it be attributed to past changes in global climate? Or are the observations just wrong?

Jan 1, 1990

By J P. Hsi

Recent increase in the development of underground space in urban areas in Australia has included soft ground tunnel construction. The ground movements associated with soft ground tunnel construction may present risk to other existing and proposed structures in the nearby vicinity. Much experience has been gained both in the UK and Asia in recent years in the engineering evaluation of this risk. The paper presents a procedure to assess these aspects of soft ground tunnel construction with reference to recent projects.

Jan 1, 1999

New knowledge has no economic value unless it can be applied, or æcapturedÆ, as the R&D jargon has it. Australia probably spends more than $500 m per year on mineral industry R&D, distributed amongst the mining companies (IR&D Board, 1997), CSIRO, the universities and others. The investors in this research (industry, and the community via government) will expect some sort of return from their investment. The return will be poor unless the know-how developed in R&D programs can be exploited. This paper explores some of the issues involved in capturing the outcomes of mineral industry R&D in a form which can be exploited for economic benefit, and suggests ways in which it might be done better. It is based on the experience of the JKMRC in conducting applied research in mining and mineral processing and delivering it to the industry. It may seem presumptuous for a research contractor to be telling its clients how to do their job. However, the process of developing, acquiring and implementing R&D outcomes has to be a partnership between provider and receiver, in order for this process to work efficiently. This applies whether the two parties operate within a single corporation (a corporate laboratory and a business unit, for example) or are two entirely independent organisations (eg a mining company and a university). Both partners have a role to play, and the best examples of realising the benefits of R&D almost always involve the open-hearted and skilful handling of this synergy.

Jan 1, 1998

By C Xu, B Li

Multi-sensor fusion visual perception technology significantly enhances visual perception capabilities in complex and harsh environments by combining visual data from different sensors. This technology is especially useful for scenarios where traditional single visible light sensors, such as standard cameras, struggle due to poor lighting, adverse visual conditions, or other visual obstructions. In environments with low light, smoke, or dust, the performance of conventional visible light sensors degrades, limiting their application. By integrating data from various sensors like radar, infrared thermal imaging, and others, multi-sensor fusion technology provides a more comprehensive and complementary visual solution. This fusion not only enhances the robustness of visual systems but also greatly expands their potential applications in fields like visual surveillance. In recent years, deep learning methods have become the mainstream technology for addressing multi-sensor fusion issues, demonstrating significant advantages in adaptive feature selection compared to traditional machine learning methods. However, deep learning-based multi-sensor fusion algorithms still face several challenges. The design of network structures is often redundant, lacking effective screening of useful components within multimodal information. Mainstream fusion algorithms focus excessively on improving display effects without adequately considering the needs of downstream applications and tasks. Existing fusion perception algorithms are generally designed for open visual scenes and lack targeted design for complex visual degradation factors present in tunnel environments of mines. Current deep learning methods for designing multi-sensor fusion networks heavily rely on manual experience to create fusion modules. This reliance increases the complexity of network design and can lead to redundancy. Redundant network modules are difficult to identify in end-to-end learning tasks at this stage, significantly slowing down network inference and potentially interfering with the output of fusion perception. Additionally, training these fusion modules typically requires large amounts of well-annotated multimodal data, further increasing implementation difficulty and cost. For instance, the fusion network design proposed by Li and Wu (2018) focuses on extracting multimodal fusion features, while Zhao et al (2020) introduced a feature decomposition mechanism in the feature fusion and extraction modules. Researchers like Zhang and Ma (2021), Xu et al (2020), and Liu et al (2017) have attempted to improve network structures through dense cascades and the introduction of residual connections. Although these methods have improved the handling of multimodal information to some extent, they still face limitations in distinguishing between useful and redundant information, with redundancy persisting in network designs. Ideally, the design of fusion networks should be more intelligent, guiding network structure design heuristically based on the importance of different modal information for the current task. This would reduce information redundancy and network weights, requiring the development of new algorithms or frameworks capable of automatically identifying and optimising fusion strategies, thereby reducing dependence on manual experience while improving fusion efficiency and network performance. Current deep learning designs for multi-sensor fusion algorithms often overlook the

Sep 1, 2024

Production scheduling is an important element of the mine planning process. The production schedule specifies the quantities of mineral to extract, the source of this ore, the timing of extraction and, where necessary, the quantity and timing of backfill placement. These details are important in linking long-term strategic goals to short-term operational planning. Mine scheduling techniques form the basis for communicating information concerning the overall impact of design and planning changes to a wide range of people at many levels within an organisation. Consequently the techniques used for mine scheduling must support the decision-making process by consistently providing high quality schedules in response to revised and updated data. A new mixed integer programming (MIP) model has been developed to generate optimal production schedules for underground stoping operations. The model maximised the before-tax Net Present Value of the production schedule while satisfying constraints such as contained metal tonnage, hoisting capacity, stope geometry relationships and stope backfilling demands. Zero-one variables were used to represent the decision to extract or backfill each stope in a particular time period. Continuous variables, capable of having non-integer values, were used to denote the quantity of ore or backfill associated with a specific stope in a given time period. A case study is presented to demonstrate the significant improvement in before-tax NPV over a comparative manual production schedule in a large underground mine. The MIP model allows for further modification to reduce solution times and meet the needs of individual mines.

Jan 1, 1995

By D Laurence

Significant developments in future mining systems, technology and best practices are emerging that are driven by issues relating to human resources, competitiveness, environmental and social responsibility, within the dynamics of globalisation. It is proposed that the definition of the role and attributes of the mining engineer in the mine life cycle needs to be viewed more holistically in the face of increasingly more diverse and complex responsibilities. These developments are motivating the need to consider a fresh approach to mining education and training at all levels for industry. A growing diversity and complexity of professional responsibilities is extending the mining engineerÆs broadly based skill set and reinforcing the need to play a central role within increasingly interdisciplinary teams. On the other hand, the imminent new technologies that will transform the mining process are prompting the assumption that more focused and specialised skill sets will be needed. A way forward is suggested that would first define a blueprint for the future mine, as an attempt to characterise the systems architecture, processes and organisation of the next generation mine. This can be the basis for assessing the nature of the workforce and distribution of responsibilities, from which can be inferred the skills and training requirements. In the context of the mining engineer, the paper explores how understanding such future requirements will enable more proactive development of a strategy for educational development. The paper then concludes by considering issues and lessons learned from some recent mining educational development initiatives underway in Australia and Canada that are shaping significant change.

Jan 1, 2008

By Boland J

Prediction of rock cuttability by various excavation machines such as tunnel boring machines, road headers, rippers, picks, roller disc cutters, excavators, etc is of major concern to both civil and mining engineers and rock mechanics. In principle, the design of a rock cutting tool is based on achieving maximum excavation with minimum input energy, minimum applied force, minimum equipment weight and volume and, more importantly, minimum tool wear. When a rock material is indented by the force of a cutting tool and then unloaded several material zones form underneath and around the tool. As the tool moves into the rock the volume of its associated rock cavity (ie volume of displaced rock) expands and depending on the indenter's shape various phenomena may occur. Immediately beneath the tool a small zone in which the stress state is more or less hydrostatic, is formed which is underlain by an inelastic, or damaged, material zone. Both size and shape of this damaged zone control the magnitude of the indentation force and the chip formation mechanism during unloading. The rock is unable to store the whole strain energy induced by the tool and consequently the extra energy is expended either in forming new fracture surfaces and/or in plastic deformation in the damaged zone. Therefore, it is not surprising to see that both perfect-elastic and rigid-plastic constitutive models are not generally suitable for modelling indentation of rocks. In contrast elastoplastic constitutive models are more appropriate as they can include both elastic and plastic deformations (Kral et al, 1993). Elastic solutions for several half-space indentation problems can be found in most text books on elasticity and in particular in Timoshenko and Goodier (1951), Sneddon, (1951), Poulos and Davis (1974) and Johnson (1985a). If a failure criterion, eg the Mohr-Coulomb failure criterion, is applied to delimit elastic solutions for indentation problems, a lower bound limit of the applied indentation force (for a given indentation depth) can be estimated. It may be noted that elastic analyses, without any delimiting failure criteria, normally overestimate the indentation force. Plastic solutions for a few indentation problems may be found in Hill (1950), Johnson, (1985a) and Alehossein et al (1992). When analysing the behaviour of indented rocks the choice of an appropriate constitutive model describing effectively the behaviour of the rock at various stages and phases during indentation is a challenging issue. Several questions need to be answered before starting an effective analysis. The first question is of course: Which one of these is more appropriate for modelling zones underneath and around a cutter, elasticity or plasticity theory, continuum damage mechanics or fracture mechanics, and what is the bridging link between these various theories? Which mode is more dominant in fracturing rock, tensile or shear mode? What governs the mechanism of chip formation? What is the function, shape and the behaviour of the pulverised zone that forms just underneath a cutter? Is the hydrostatic stress state assumption reasonable for this zone? How does the rock change during the absorption and dissipation of the input energy and how does the indentation energy vary with rock type and depth of penetration? How can we model the damaged zone under the indenter? Furthermore does a plastic material form beneath the pulverised zone? When and how do radial and ring cracks form around and under an indenter?

Jan 1, 1995

Shortly after the outbreak of war in September, 1939, it became apparent that considerable quantities of certain metals and alloys which at that time were not being produced in Australia would be required in increasing amounts for the prosecution of the war effort.Australian industry had relied on overseas sources of supply for the relatively small quantities of many special metals which were needed under peacetime conditions. As the war progressed so great became the demand for mooy of these alloys in Great Britain and other allied countries that it was necessary for them to place an embargo on the export of these materials, and thus it soon became evident that if Australia's production of munitions was to expand and develop it would be necessary for her to become independent of overseas sources for many of these essential 'items. The shipping position also became very acute, and this, accentuated the difficulties of obtaining these alloys. Because of the conditions outlined aqove, the manufacture of over thirty different metals and alloys .was undertaken at Newcastle during the past decade. It is with two of these that this paper proposes to deal. They are tungsten powder and ferro-silicon.TUNGSTEN POWDERTungsten is a rare and comparatively new metal. It is used extensively in the production of high speed tool steel, some grades of which contain up to 22% tungsten. Such articles as twist drills, reamers, milling cutters, and lathe tools are made from tool steel, and the demand for these during the war years was greater than ever before. The use of tungsten in the manufacture of high speed steel was first developed in 1914 by the Germans, and when it was discovered that they were using tungsten bearing steel for the production of munitions there began a world-wide search for ores of this rare metal.

Jan 1, 1947

By Eoffe SW

The wide application of computers in beneficiation plants has resulted in the creation of a number of complex automatic control systems at all stages of ore dressing processes. To create such systems it is necessary to solve complex problems of analysis and calculation. The application of computers to solve these problems demands development of simple and effective methods of investigation and simulation of ore dressing process dynamics because all the known methods are complicated in usage and cannot guarantee the desired accuracy and quality of process control. A new grapho-analytical method of investigation and calculation of ore dressing flow sheet dynamics, worked out by the authors of this paper, is based on proportion method development and is used to construct dynamic characteristics of the investigated processes. It is possible to use the given method for investigating benefication schemes with flotation machines having non-linear static characteristics and circulating loads. The suggested method of investigation of concentration flow sheet dynamics allows us to obtain dynamic characteristics of technological process parameters in both linear and non-linear systems. Moreover, the final result can be obtained without labour consuming analytical calculations by a simple graphical construction based on the static characteristics of the known equipment and processes.

Jan 1, 1993

In this paper presented are the criteria used when assessing the harmfulness of shocks affecting the buildings. Those criteria are based on the value of speed or accelerations of building vibrations. Presented is the scale of harmfulness of vibrations of Langefors and Kihlstrom, Bureau of Mines, and SWD contained in the Polish Norm PN-85/B-02170. The parameters of the mining shocks measured by the Lubin coal mine station were compared with the parameters calculated as per the correlations (regression curves). The average acceleration calculated from the correlations for eight measurements is only two per cent higher than the actual one. But the average frequency of vibrations calculated from the correlations for eight measurements is as much as 2.22 times lower than the actual one. In order to analyse whether that takes place in the whole range of the energy of shocks compared were the results of calculations from the correlations for various magnitudes of shocks and various distances from their epicentre with the results of the measurements. From that it follows that only for the shocks of the highest energies the lowering of the frequency of vibrations by two times causes movement from the higher zone of harmfulness to the lower one (for example from the IV to III). In the one-family houses in Lubin there were the damages that are characteristic for not only for the III but also for the IV sphere of harmfulness as per the SWD scale. That should be explained via further research and maybe it would be feasible to draw out a new correlation to determine the frequencies only for high values of energy of shocks and determine the preciseness of the acceleration and frequency correlations used presently.

Jan 1, 2003

By Milawarma E, Cusack C

The Sapan Dalam coal deposit of Indonesia consists of ten steeply dipping seams with thicknesses varying between 0.1 and 3.5 m and split by shale, clay, silt and sandstone. The area contains four faults dipping about 75¦ with four to 85 m vertical displacements. The complex nature of the deposit coupled with limited 27 exploration drillholes at an average spacing of 200 m made it difficult to create a realistic geological model. A three-dimensional gridded seam model gave a fair representation of the deposit. Attempt to create an optimum pit using the WHITTLE 3D pit optimiser proved unsuccessful since the pit optimiser is restricted to standard regular or fixed blocks. The gridded seam model was converted to a fixed block model prior to the optimum pit design. Smoothing and pit base controlling were also introduced to obtain a smoother pit. A mining scenario produced 3.6 million tonnes of coal, 28.4 million bcm of waste and US$18.1 million revenue.

Jan 1, 1995

Major exploration companies can have a problem with what to do with small precious metal ore bodies located through exploration programmes. Low tonnage, but high grade, ore bodies too small to justify in-house development.1.2 Ban Ban Mining is a Sunshine Coast based partnership with considerable expertise in mining and earthmoving which specializes in the mining of small/medium size ore bodies on behalf of the tenement holder on a profit sharing or royalty basis.1.3 The partnership's first successful venture has been the mining and vat leaching of a small 40,000 tonne ore body with a head grade of 5 gm/tonne gold and 32 gms/tonne silver, situated near Ban Ban Springs in southeast Queensland.1.4 This paper looks at the low cost vat leaching method of treatment, as an alternative to CIP and CIL in the processing of low tonnage/high grade precious metal ore bodies.

Jan 1, 1990

Autocompression and virgin rock tempera ture have a marked influence on the ventilation of the lower levels at North Broken Hill Limited N.S.W. To maintain comfortable working temp- eratures without penalty to working hours, increase in airflow or the cooling of the work area is necessary. The use of refrigerated air cooling is discussed. Ventilation of underground mining opera tions at North Broken Hill Limited is accomplished by downcasting air through No.3 shaft, the main operating shaft, 1581 m deep, with additional air through No.1 shaft (542 m) 2 and No.2 shaft (978 m), both no longer opera- tional shafts. Air is upcasted through No.3 ventilation shaft which is 4.9 m diameter and concrete lined, from the No.28 level (1140 m) to the surface. On the surface level of this shaft is a horizontally mounted Richardson 4800 mm diameter single stage axial flow fan with adjustable pitch rotor blades.

Jan 1, 1977