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By S Slusarczyk, Z Kozlowski

Vibration of surface caused by seismic quakes can make a risk to great mining costruction. We have to do with this risk in the Belchatow open cut mine where seismic quakes of various energy and range have occured since the end of 1970s. The seismic risk influence on the mine structure with the special attention to the slopes of an internal dump has been presented. Hydrogeological and geotechnical conditions of the lignite mining and internal dumping of overburden and ash from Belchatow power plant have been considered. Seismic activity in Belchatow open cut from 1979 to 2001 was described and the connection between mine working and seismicity of this area was investigated. The energy and approximate location of the quakes and seismological parameters of the strongest ones observed from 1995 to 2001 were presented. The mechanism of the quake focuses was determined by means of the primary-arriving wave method. Stability of the slopes was evaluated by means of the Fellenius method. It has been found that seismic events occured in Belchatow region may cause only local eboulements whereas there are not any safety risks to the stability of slopes of the internal dump in Belchatow open cut.

Jan 1, 2003

A wide variety of process streams are sampled for grade control in the mining industry. However, in many instances the overall precision of the resultant analyses is inadequate for the intended purpose, ie grade control and optimisation of resource utilisation. Consequently, special attention needs to be given to the sampling, sample preparation and analysis procedures in place to ensure that meaningful grade control decisions can be made based on the analyses generated. For example, it is virtually impossible to control a process to within, say, ¦0.2 per cent if the overall precision of the analyses is no better than 0.5 per cent. Hence, precision targets appropriate for the task need to be established and the overall precision achieved in practice monitored and controlled on an ongoing basis.

Jan 1, 2008

The use of ammonium nitrate/fuel oil explosives is.now well established in most open cut mining operations. Its use. is extending to underground mining. This has been due in a large measure to improvements in the nature of the ammonium nitrate made available from various sources. The addition of surface active agents and water in controlled amounts to the fuel oil has been found to increase the sensitivity of the ANJFO mixture with consequent better explosive properties. It is considered that the surface active agent increases the bond between the ammonium nitrate and fuel oil giving a more, intimate physical and chemical mixing of the oxidising and reducing agent. This results in increased sensitivity and a faster rate of reaction. The increase in sensitivity has been accomplished without any diminution of safety. Tests which demonstrate the safety of this type of explosive are given in the appenuix.

Jan 1, 1964

The growth of the mining industry around Australia over the last ten years has seen many open cut mines developed on shallow oxide reserves. Most of these have been gold operations, although there are some copper mines in the list, too. Many of these have exhausted their oxide reserves and have made the transition to underground mining to access their deeper sulphide ores. Other operations have reached or are approaching the point where the decision has to be made to go underground or cease mining. This paper discusses the issues involved in making the transition from surface to underground mining. The aim is not to discuss each of the issues exhaustively. This would take a conference in its own right. Nor is it intended to provide a primer on underground mining. Instead the aim is, firstly, to flag the issues which must be addressed when planning to make the transition from surface to underground mining and, secondly, to identify critical aspects of mine development.

Jan 1, 1997

Sluice-boxes are by far the most widely used concentrating devices by small-scale operators in PNG who work alluvial gold deposits. The sluice-box designs and their operating conditions used are known to vary widely. The selection of sluice-box configuration and the operating parameters such as the water flow rate is purely based on past experience. Some use small flowrates to increase the fine gold recovery at the expense of efficient separations and capacity while others use high flow rates resulting in increased fine gold losses but with high throughput rates. Recent work has revealed that the combination of riffle height, their spacing and wash water flow rate are the most important parameters that determine the success or failure of such operations. This combination has been shown to depend on the in situ gold and gangue size distributions of the deposit being processed. This paper describes a design procedure which uses a non-linear optimisation method to determine the optimal combination of the above parameters to maximise the metallurgical efficiency of such operations.

Jan 1, 1993

By I Grant

On the 1 June 1978, the Town and Country Planning Act 1953 was replaced by the revised and more comprehensive Town and Country Planning Act 1977. The new act brings in some substantial changes to the law affecting regional and district planning, and for the first time makes provision for maritime planning. The importance of the Town and Country Planning Act 1977 to the Mineral industry is primarily in the relationship between Regional Planning Schemes and District Schemes as the needs and resources identified in a Regional Planning Scheme will override the underlying District Schemes. The mineral extraction industry must be recognised as a regional responsibility which draws on the resources of a region to satisfy the demand of the communities within that region rather than a purely local operation within one District.

Jan 1, 1978

To meet the objectives of sustainable development, mining projects must be executed with minimal environmental risks and impacts. To allow proper actions to be taken, it is helpful if the environmental challenges associated with a mine development project can be predicted early during exploration activities. Signs of impending environmental problems like acid rock drainage and metal leaching are often revealed in the occurrence of natural acid drainage, formation of efflorescent salts and their associated ecological effects. Other subtle clues can be deduced from anomalous geochemistry, detailed textural features of mixed sulfide assemblages and miscellaneous environmental data sets covering the target areas of exploration. A more practical tool, however, is the development of comprehensive environmental ore deposit models containing relevant information on ore genesis, applicable mining, processing and waste management options and their environmental implications according to deposit type. Not only will such models facilitate communications among independent groups of personnel involved in a mining project to come up with schemes to ensure better environmental performance of the overall project, they will also facilitate decision-making if a mine development project should be pursued further or valuable resources be redirected to other more favourable targets.

Jan 1, 2003

By N J. Betts

This paper aims to build on the strong emphasis that was placed on safety in the Sydney AITES-ITA Congress in March 2002. It will do this by comparing safety records from some major tunnelling projects in Europe and Australia over a period commencing in the second half of the 19th century to the second half of the 20th century and examining reasons for the apparent marked improvement that appeared in the 1980s. Further by looking at the relationship between this improvement and current trends in the australian industry by means of a detailed review of the safety record for the Northside Storage Tunnel project in Sydney which was completed in mid-2000. The paper will conclude by providing a summary of the progressive approach adopted by the minerals industry in australia and summarising the current state of tunnelling and underground construction in australia with respect to recently completed projects and potential major initiatives.

Jan 1, 2003

By Y Hansen, J Petrie

Life Cycle Assessment (LCA) is increasingly being used as a decision-support tool within mining and minerals processing and metals production. However, a number of initiatives have highlighted the current limitations of LCA to accurately reflect the environmental performance of minerals and metals. These programs include:the Mining, Minerals and Sustainable development project (Stewart, 2001); the United Nations Environment Programmme/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) workshop on LCA and metals (NRCan, 2002); the UNEP SETAC Life Cycle Initiative; and the review of the existing ISO 14 040 set of environmental management standards. Together, these initiatives highlighted concerns relating to the ability of LCA to engage with and support metals recycling, to adequately reflect the impacts associated with products from a multi-product orebody, the ability to adequately reflect the toxicity potential of metals in the natural environment and the fact that resource depletion focuses on mining (and not consumption) as the depleting activity in the life cycle of a metal. Additional impact categories to be included in LCA were also suggested. In this paper we demonstrate how existing initiatives are addressing LCA limitations. Finally we present the state of the art in Life Cycle Impact Assessment (LCIA) for two impact categories:resource depletion; and impacted land footprint for solid wastes.

Jan 1, 2004

This paper explains why the valuation of mining assets is often a very different exercise from the valuation of the shares in the mining company which owns those assets. The fundamental reason for this is that mining assets, and the shares of the company which owns those assets have different risks. In order to properly value mining securities it is essential to: ò ensure all the different risks and other factors which impact on the value of the mining assets and the value of the shares are taken into account; and determine the extent to which the different risks and other factors are addressed in the value of the mining assets and the value of the shares so as to avoid double counting or not counting at all. If the alternative, but far from consensus, view is accepted that the correct valuation methodology to apply to shares in mining companies should be based on option pricing theory then conventional valuation practice of both mining assets and shares in mining companies will need to be fundamentally reassessed.

Jan 1, 1994

In recent years a number of explosive blends including ANFO, emulsion and watergel products have been used in a variety of ground types and applications. These `standard' explosives' technologies are not new, but out of the uses and applications, have sprung a new generation of tailored explosives that match the ground type and the operating environment. This is in stark contrast to the norm, where various patterns and loading configurations have traditionally been designed to accommodate the explosive. This paper discusses these tailored explosives and the explosives' technology behind why they work. Active tailoring of explosive formulations can save mining dollars while essentially leaving the explosive price unchanged. Tailoring explosives may lead to increased rock breakage, heave, digging rates; lower digging maintenance costs and in some cases replacing earth moving machinery altogether. Tailored explosives may have other benefits such as reduced over pressure compared with standard alternatives. The tailoring of explosive performance generally involves three major methods (other than changing the bulk density and sensitivity): (i) replacing fast burning reactants with slower burning reactants or vice versa; or (ii) leaving the explosive intact and diluting the entire explosive with slow burning or `inert' material; or (iii) changing the concentration of the fuel/oxidiser mix. When tailoring explosives for particular applications, authorising, testing, costing, manufacturing, and delivery systems must also be taken into account.

Jan 1, 1995

Proper technical appraisal of a coal deposit and the determination of optimum open- pit mine design can only be made after detailed examination of a number of interrelated geographical and geological factors. Initial evaluation of the geography and the overall attitude of the coal measures can often determine the most likely coal mining technique. Conclusions reached in the early stage of the investigations frequently dictate the quality and quantity of particular types of data required from further drilling of the deposit. In many cases, insufficient information relating to the overall engineering aspects of a coal deposit is derived from drilling. Little or no attention is paid in the exploratory phase to such things as the specific gravity of selected overburden samples, floor conditions, clay content of the overburden and selected strength tests on cores. This is a direct result of geologists treating coal deposits purely in geological terms without sufficient consideration being given to the engineering parameters required for a proper evaluation of the deposit.

Jan 1, 1977

By E U. Petersen, D R. Cooke

Hydrogen and oxygen isotopic constraints on hydrothermal fluid composition from the Pliocene Boyongan and Bayugo porphyry copper-gold deposits (southern Philippines ) reveal mixing of magmatic and sea water reservoirs as the hydrothermal system evolved. Magmatic-equilibrated fluids (d18O: +8.3ë to +9.1ë; dD: -61ë to -51ë) are represented by hypersaline brines implicated in copper-gold transport and deposition. These dominate the fluid inclusion assemblage in early comb-quartz (unidirectional solidification textures), miarolitic quartz, and in K-silicate-stage quartz-K-feldspar ¦ biotite veins. Fluids responsible for post-K-silicate alteration assemblages of pyrite-clay (illite, pyrophyllite and kaolinite), alunite and smectite are represented by low-moderate salinity two-phase inclusions in co-existing quartz. These are interpreted as mixtures of evolved magmatic fluids (d18O dD: -42ë to -20ë) with evolved Pliocene sea water (d18O: + 4.0ë; dD: +4ë). The isotopic evidence for sea water involvement in the hydrothermal system suggests that porphyry emplacement and associated diatreme formation could have occurred in a submarine setting. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Coal pillar design has been based on generalised formulae of the strength of the coal in a pillar and experience in localised situations. Stress measurements above and in coal pillars indicate that the actual strength and deformation of pillars varies much more than predicted by formulae. This variation is due to failure of strata surrounding coal. The pillar strength and deformation of the adjacent roadways is a function of failure in the coal and the strata about the coal. When the pillar is viewed as a system in which failure also occurs in the strata, rather than the coal only, the wide range of pillar strength characteristics found in the UK, USA, South Africa, Australia, China, Japan and other countries are simply variations due to different strata-coal combinations and not different coal strengths.This paper presents the measured range of pillar strength characteristics and explains the reasons. Methods to design pillar layouts with regard to the potential strength variations due to the strata strength characteristics surrounding the seam are Presented.

Jan 1, 1998

The increasing introduction of high capacity mechanical equipment into the coal mines of New South Wales following. tforld War II brought with it problems of roof support. Rapidly advancing headings in difficult country could not be supported with heavy, close,timbering due to the time involved in installation and the reduction of available' space for the movement of machines. _ The installation of low cost, space saving, rapidly installed roof supports became a necessity if the new mechanical equipment wa-s to be allowed to operate at maximum efficiency. As, a result of experience in the United States of America, the system of roof support using steel reinforcing bolts began to find increasing, popularity in the mechanised mines in this State. From the somewhat'crude methods of in- stallation adopted in some of the, early trials, the practice of roof bolting has advanced into a-highly technical operation, requiring care and skill to ensure optimum results.

Jan 1, 1971

As a number of underground fires have unfortunately happened in the Broken Hill mining district, the writer trusts that a paper dealing with such a subject may prove of interest. To simplify matters, the subject is classed under three mainheadings- I Origin of fires; II Methods of subduing them; III Precautions to minimize the risk of their occurrence.Underground fires may be started in three ways - arson, spontaneous combustion, or carelessness.With regard to the first-mentioned cause, direct evidence is usually lacking to prove that any fire has been caused maliciously; Though definite proof of spontaneous combustion having been the cause of a mine fire has not been brought forward, nevertheless it should be considered, especially in the case of sulphide ore bodies of a more or less friable nature. The writer has been informed on reliable authority that in an open stope on the...

Jan 1, 1911

By Sheridan GD

Fifteen samples 'of clays and shales from the Adelaide area were selected from a total of 84 as representing material of possible value for the manufacture of light-weight aggregate. A detailed examination of the bloating. characteristics of these revealed four likely to be suitable. for expansion.' in a rotary kiln. One of these, a Tapley. Hill shale., was-fired in an 8 in. diameter rotary kiln, but con-tinuous bloating without ring formation in the kiln was not achieved. Steam,,-oxygen,, sulphur dioxide and carbon dioxide have been, suggested. as the agents of bloating. An examina-tion of .. the evidence : `leads to the conclusion that carbon dioxide derived from. carbonate minerals is likely to be the principal bloating agent. Attempts to bloat clays by the addition of mica were.not successful.

Jan 1, 1963

By Nettle W. H V

THE past few years have seen a considerable expansion of the roasting of blende in Australia. The bulk of this blende is Zinciferous concentrate from Broken Hill and now forms a very considerable source of sulphur for the acid manufacture. It will bereadily conceded that Australian sentiment is in favour of utilising all known potential wealth, especially that won from below ground, as this once disposed of is gone forever. If Australia does not make sulphuric acid from her sulphide ores we may be sure that the purchaser of these ores will do so if in any way possible. It must not be assumed, then, that the difficulties met are mentioned with the idea of undue criticism, but rather to show that, although most of the intial troubles have been overcome, there are still a few to be encountered; and with the hope that comment brought forth will aid in the solution of the problems facing an industry at present little more than in its childhood as far as Australia is concerned.Blende roasting is done in mechanical furnaces of various makes, and mostly without the aid of other fuel than the sulphur in the ore. It will be our aim to touch on the various difficulties in the order in which they occur in the train from furnace to acid plant.

Jan 1, 1926

By S J. Henderson

Pumped co-disposal of coal processing waste was promoted in the 1990-2000s as a low-cost highperformance alternative to tailings dams. In particular it would avoid high up-front capital for rejects trucks and dam embankments, and would produce a combined waste deposit with better geotechnical properties than either coarse rejects or tailings. Overall, the promise was not delivered; in particular, upon discharge the waste segregated by size, and operators responded by moving the coarser waste to contain the finer waste. In consequence, not only did design analysis lag behind construction, but some of the initial expectations persisted with the result that analyses did not fully represent what was occurring on the ground. After more than twenty years inspecting, designing and tending Co-Disposal Areas (CDAs), it is apparent that they are essentially upstream constructed tailings dams with some more favourable aspects but also a few unique quirks. Although waste management technology has moved on somewhat, the high cost of changing CHPP waste circuits means that most mines with pumped codisposal will continue to discharge mixed waste slurry into CDAs. It is therefore worthwhile to share some lessons in the hope of promoting sounder design, operation and rehabilitation. These include: • Discharged waste does not form a homogeneous wholly competent deposit but instead comprises materials ranging from sandy gravel to silty clay with the distribution determined by movement of the discharge and decant structures; • CDAs circulate and contain a lot of water; • As a result of the first two points, some areas of the CDA comprise saturated fine waste that is no different from tailings and, like tailings, often behaves in an undrained manner; • Seepage is inevitable and desirable because strength improves as water is removed. However, stability is strongly impacted by pore pressures and in design these need to be rationally rather than optimistically considered; • As CDAs are built to about 40m or higher, strength-deformation characteristics of the foundation become more important; • Even if geomechanically stable, CDAs will need covers to prevent salts and acids from reaching the surface; and • Erosional stability of the cover material(s) will probably dictate maximum slopes for rehabilitation.

Jul 1, 2021

By R Lau

The fire safety design for road tunnels includes the following aspects: active systems, passive provisions and operational procedures. The active systems include the smoke control system, fire suppression system, detection system and fire fighter’s assistance systems. Passive provisions include escape passages, fire separation and fire resistance systems. The operational procedures refer to fire fighter access, reporting and alerts, evacuation processes and crowd control.Currently, these systems are typically designed by different designers or teams. These systems are intended to work together in a coordinated manner to provide the desired safety outcome. However, in practice, this is not always happening. The fire engineering process is supposed to bring together all these aspects and arrive at an integrated safety system. The fi re engineering process in practice is not integrating the design with the practice or reality and is thus arriving at less than desirably efficient safety systems.The example of design inputs shows how disconnected each system design basis is. The smoke control system design is based on the design fire size. The performance of the smoke control system is to achieve a smoke free environment for a defined space for a particular fire size – the design fire. The fire suppression system – most commonly sprinklers or deluge systems, is designed according to codes and to achieve a certain water discharge rate. The fire detection system is designed to detect temperature rise/rate of rise and perhaps density of smoke. Fire separation is determined to provide a certain period of service – mostly for structural elements. Escape route size and location is determined mostly by code compliance. Evacuation procedures are determined by Authority operational requirements rather than human behaviour.To arrive at an integrated fire safety system, the design basis and performances must be coordinated. An approach using fire scenarios would ensure all systems are designed to a common performance requirement. This paper will discuss how the current design approach outcomes compared with a fire scenario approach. More effective and efficient fire safety systems would require the stake holders to understand the implication of this approach and to embrace this through the fire engineering process.

Mar 8, 2011