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By D Morrison

Backfill is usually considered a necessary evil that contributes little to the principal objective of the operation, ore production. Consequently, it is relegated to an auxiliary role in the operation with minimal equipment and resource allocation in planning and is only superficially considered during feasibility studies. In many mines, the inadequacy of the design and operation of the backfill system ultimately leads to frequent delays, excessive costs and, in the worst cases, major instabilities which result in reduced ore production and lost or unrecoverable ore reserves. The primary objective of backfill is to prevent the progressive deterioration of mined out excavations. With the exception of narrow vein operations, it is too weak to alter the mining induced stress regime and control stress concentrations caused by stope extractions. However, the direct benefits of backfill include the possibility to consider a wider range of mining methods, recovery of 100 per cent of the planned resource and the selection of a stoping sequence that minimises the regional stability problems that cause production shortfalls in the later years of mine production. Indirectly, backfill is a practical means of solving other issues, such as waste disposal, that impact the viability of mining. In Australia, the geotechnical conditions of many mines are becoming more difficult and increased attention to the importance of backfill is warranted. This paper describes realistic aspects of backfilling and the positive impacts a well co-ordinated fill system can have on mining activities as a whole. Examples are presented where an integrated approach to backfill systems have offered significant benefits to the operation.

Jan 1, 1998

In February 1995, Falconbridge Limited approved the construction of a nickel mining and milling facility on its Raglan property situated in the Nunavik region of northern Quebec, Canada. The construction period successfully terminated with the commissioning and start-up of the plant and concentrator in early-December 1997. The estimated life of the project is 20 years with an annual mining rate of 800 000 tonnes of ore, producing 21 000 tonnes of nickel per year. This paper discusses the subject of æRemote Mining in the Canadian ArcticÆ as it applies to the Raglan mine process and people. During the feasibility stage of the project, many assumptions were made which influenced the design and operating parameters of the facilities and the equipment. Transportation, communication, remote logistics techniques and standard industry practices required to support a æfly-in/fly-outÆ operation were reviewed and either adopted or rejected for use at Raglan. These assumptions were æmade to fitÆ the uniqueness of our planned operation. It was also acknowledged that many of them would ultimately impact on the people required to staff the operation following construction. Therefore, their suitability and applicability were examined from an economic, operational and human perspective. In a continuing effort to improve the quality of life for Raglan employees, as well as the economics of our mine operations, these assumptions are under constant review and scrutiny. There is no doubt that experiences gained, and willingly shared by other North American arctic mining operations, proved invaluable and are a big reason for RaglanÆs overall success thus far. The mining industry is being challenged technically to develop lower grade orebodies at the lowest possible cost. In addition to environmental constraints, serious social, political and moral questions are being asked and added to this list of challenges. Miners throughout the world must improve their operating standards and public image if we want to attract the best possible employees. Remote mining operations provide a unique opportunity to experiment with various human resource concepts as well as demonstrate the industryÆs commitment to environmental and community concerns.

Jan 1, 1998

By Walker K, Burton RC

An outline of the ventilation and refrigeration requirements of deep South African gold mines is presented. This is followed by a brief description of the history of controlled recirculation in mines and the practical and economic benefits such schemes can offer. The potential hazard of a fire in a recirculation system is discussed.The major part of the paper describes the first large-scale field trial of controlled recirculation to be conducted in South Africa. Emphasis is placed on the monitoring system that was used for data acquisition during the trial, and also on a safety system designed to shut off the recirculation fans in the event of a fire.The paper concludes with a review of the latest development work taking place on recirc-ulation safety systems.

Jan 1, 1985

Outline of situations when valuations required - from capital raisings and takeovers, stamp duty, rates and capital gains tax, to probate and litigation between joint venture parties. Definition of types of exploration and mining properties as background to discussion on what methodologies to use (from grass roots to operating mine). Discussion on nature of alluvial deposits in New Zealand and how their characteristics and tonnage/grade uncertainties affect choice of methodology. Assessment of risk factors in New Zealand û technical, financial and socio-political (legislation, access, Maori land rights, environmental). Discussion of appropriate methodologies.

Jan 1, 1992

In this paper is given a description of the flotation plant recently erected by Broken Hill South Limited at the South Mine, Broken Hill, N.S.W. It has been built on the site of the old flotation plant, which was described in a previous paper published by the author. The present paper is supplementary to the former paper in that it replaced the following sections thereof, namely, those from end of the second paragraph, page 269, to the end of the first paragraph page 282, and from the end of the second paragraph, page 284, to the end of the third paragraph, page 302.The roll crushing, fine grinding, gravity concentration, filtration, disposal of products and sampling in the new plant are the same as described in the above mentioned paper.The reconstruction of the flotation section, described herein, completes the reconstruction and modernisation of the treatment plant which was begun in 1928. A description of these earlier alterations has already been published in the Proceedings of this Institute.

Jan 1, 1935

Simple parameters, capable of easy observation on-site under operating conditions without interruption to production, are outlined for the operational assessment of underground conveyor systems. Recording techniques, methods of analysis and deduction of operational characteristics are discussed for batch inputs to several points of a multiple belt conveyor system with limited inter-belt storage capacity. Particular attention is given to input and output load- time distributions, utilisation of inter-belt storage capability and system shutdown behaviour. Actual data, observed for a transfer feeder located between two trunk conveyor belts in an underground coal mine, is used to illustrate the operational assessment of an underground system. Load sensitive feedback systems-are briefly considered.

Jan 1, 1982

By L N. Loganathan

Risk exposure in tunnel projects is extremely high due to various factors such as variability of subsurface conditions, selection of inappropriate design and tunnelling methods, improper risk assessment on adjacent surface and subsurface structures and utilities, and inadequate contractual practices. The risks in tunnelling must be borne by the contractor, designer and the owner of a tunnelling project. There have been a number of improvements in the last ten to 15 years in the manner in which tunnel projects are developed and implemented in terms of their design, construction, financing and operations. One significant improvement has been the manner in which underground conditions and their risks are being managed. Owners are less willing to transfer the full responsibility to the contractor for managing the underground conditions, although this is a familiar manner in which underground major urban projects have been previously contracted and managed. The owners of tunnel projects in Singapore have advanced the risk management process for their projects through geotechnical interpretative baseline reports (GIBRs), geotechnical data reports (GDRs) and project specifications (PSs). This paper discusses industry practice and its development as well as the application during the preparation and use in Singapore on the Deep Tunnel Sewerage System (DTSS) and the Marina Coastal Expressway (MCE) project in Singapore. The DTSS trunk sewer is 48 km and ranges from 3.3 m to 6 m finished diameter up to 50 m below the ground. The underground conditions ranged from Old Alluvium, strengths of about 1 MPa to competent Bukit Tima granite, with strengths of over 230 MPa. The total route length of the MCE is about 5 km. About 3.6 km will be constructed underground, consisting of dual five-lane carriageways. The underground construction will be cut-and-cover, and 2.6 km will be constructed about 13 m underground, and 1 km of tunnel will range from 13 m to 24 m as the tunnel passes under a 420 m wide reach of Marina Bay, whose crossing will be constructed as a two-phase cofferdam.

Jan 1, 2008

By Richards BG, Komdeur W

Instability in spoil piles and in high wall slopes in natural overburden has been ex- perienced at Utah's Goonyella Mine since com- mencement of operations in early 1971. Annual production targets, although gener- ally met since the commencement of operations, required modifications to stripping and mining techniques and the rapid re-scheduling of oper- ations around unstable areas, but culminated in the earlier than planned acquisition of addit- ional stripping equipment. An understanding of failure mechanisms was developed within a collaborative study of pitwall instability between Utah Development Company and the C.S.I.R.O. Division of Applied Geomechanics. Results showed that pitwall instability occurs as structurally controlled deformations along planar failure surfaces; spoil pile failures are precipitated by moist- ure ingress and subsequent loss of strength of base layer materials; highwall failures de- velop over areally extensive bedding planes in conjunction with inclined and subvertical fractures caused by overburden blast damage.

Jan 1, 1978

The Macquarie Dictionary defines `information' as: knowledge communicated or received concerning some fact or circumstance; (in communicating theory): a quantitative measure of the contents of a message. For mining companies investing in data capture and information processing technology for operations management is a key issue. Beyond producing performance related information that employees can relate to it is being able to deliver that information into the workplace when it is required, to the employees that can utilise it. To be effective the data needs to be received and understood as `information'. The technology is now available and proven to enable `information' to be delivered into the mining workplace adding value to the activities performed by mine employees. The application of computers and information technology in the mining industry has typically been limited to the resource definition and planning stages, accounting and administration and the process plants that treat the ores and minerals. The mining extraction processes that consume expenditure and determine output in a mining operation occur in an environment dominated by unpredictable events and variable conditions. The mining operation has long been regarded as an inexact science conducted in unpredictable circumstances with many independent variables affecting the output and resultant cost of production. Financial accountants keep track of expenditure and management accountants analyse the cost of production usually on a weekly or monthly basis but all this effort can't affect the outcome, that was determined by the real time events and variations of circumstances over a week ago. Such reporting and analysis can result in conclusions being drawn about what improvements can be made and how you might do better next time, but generally the data is not detailed enough, is inaccurate or misrepresents the real issues. The capital investment required for any mining operation is substantial and comparable to other industries such as manufacturing. The performance and utilisation of manufacturing plants is usually closely monitored down to the lowest level of detail. Many modern plants are controlled and optimised using programmable intelligent devices and monitors display real time performance to the operators and prompt them to make informed decisions to maximise production and minimise wastage. Technology suitable for the mining industry is now widely available and has proven to be a reliable and powerful tool for the optimisation of mining operations. This paper focuses on the latest information technology developed by Modular Mining Systems that has been implemented in mining operations worldwide. The benefits reported by the mining companies utilising real time information technology over the past 15 years have generally related to optimisation of truck fleet allocation and material blending. Some mining operations have reported improvements in equipment utilisation of greater than 20 per cent. With the development of real time graphical display screens in the operators cabins the benefits of information delivery can be harnessed to make employees more effective in the workplace.

Jan 1, 1995

By Bush P. R, Hale M, Dixon C. J, Wheatley M. R

Barium anomalies in drainage sediments can act as indicators of barite mineralization and path- finders for lead-zinc mineralization. Their detection in an arid climate has been investigated in two areas of Saudi Arabia. At Rabigh, 150 km north of Jeddah, barium anomalies found in wadi sediments reflect barite veins which occupy Tertiary faults in Precambrian metavolcanics and granodiorite. In the Wadi ad Dawasir area, 650 km east of Jeddah, the sediments of wadis draining the Jabal Tuwayq escarpment have been found to contain anomalous concentrations of barium derived from diagenetic barite in the Sudair formation siltstones and shales. Barium dispersion in these wadis is predominantly clastic. Near to the source rocks, barium occurs in relatively coarse grains of barite. Owing to the three well-developed cleavages of barite, its crystals readily break into cleavage flakes during fluvial transport in flash floods; as a result, the longest anomalous dispersion trains are found in the 250 to 600 um fraction. Wadi sediments finer than 250 um have relatively constant and low barium contents, being dominantly composed of windblown sand.

Jan 1, 1988

By Berglin IK

Since 1962, ferro alloy production in Australia has been concentrated at Bell Bay, Tasmania with a major expansion occurring in 1976. This concentration was based originally on the perceived requirements of the expanding Australian steel industry, but recent stagnation within this industry has seen Temco become progressively more export oriented.In 1984, approval was given for a $47 million uprating of facilities which will allow for the introduction of the latest technology to ensure high quality, low cost production in a highly competitive export market.

Jan 1, 1985

By Hall G

The Mount Isa silver-lead-,zinc deposit possesses a number of features which sets it apart from usual occurrences of ores containing those metals. The deposit has been described in vario:us papers, but development upon deeper levels during the past two years has, yielded much information not hitherto published. Purpose of the present paper is to furnish a unified and coherent perspective by tracing briefly the full rock deformational and mineralization processes responsible for the ore deposition. The paper represents the outcome of ten years' organized geological effort at Mount Isa. Information contained in it supersedes that previously published.A bibliography of published articles relating to Mount Isa ore deposition is appended. In preparing the present paper previously published data have been drawn upon freely wherever applicable. The authors are especially indebted to the papers by Grondijs and Schouten, and by O'Malley and McGhie, which present results of systematic microscope studies of thin and polished sections from comprehensive suites of Mount Isa ore.

Jan 1, 1942

By A P MACONOCHIE

The methods used and some of the results obtained from a major geotechnical study of the Ok Tedi mine area, Papua New Guinea, are described. The study was carried out at both regional and local scales and extended over a two-year period. A team of individual engineers and scientists from a variety of disciplines carried out the work. This study may provide a model for other investigations in similar environments.

Jan 1, 1992

By Y Cao, J C. Tien

Occupational health and safety is essential in modern mining workplaces and in China it is often not given enough emphasis due to a lack of knowledge and/or appreciation. Although many health and safety regulations have been passed over the years, serious and relevant laws and regulations on mine health and safety are of recent history (since 2002), the level of stringent enforcement is still inconsistent and accurate field data are scant and not readily available. As of year-end 2006 there were 676 562 recorded cases of occupational diseases in China, of which 616 442 or 91 per cent were miners’ pneumoconiosis. Of these, 146 195 (23 per cent) have died, and an average of 10 000 new cases were added every year between 1991 and 2006. Another report shows that 93.18 per cent of miners have never had a contract with their companies, which means their cases were not even part of China’s official statistics. This study attempts to examine the prevalence of occupational diseases in the Chinese mining industry during 2000–2013, compiled from government annual reports and academic studies. The research will review the correlational analysis among occupational diseases, ventilation practices, protection devices and legislation.CITATION:Cao, Y and Tien, J C, 2015. Occupational diseases in China, with the emphasis on its occurrence in Chinese mine workers, in Proceedings The Australian Mine Ventilation Conference, pp 155–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By H S. Smit, P Lotz

Gold mining companies who are signatories of the International Cyanide Management Code (visit www.cyanidecode.org for further information) are required to measure WAD cyanide on-line and destroy WAD cyanide in excess of specified limits. Weak acid dissociable (WAD) cyanide refers to those cyanide species liberated at a moderate pH of 4.5 such as HCN(aq) and CN-, and the majority of Zn, Cd, Cu, Ni and Ag complexes with low dissociation constants. It is potentially toxic to humans and animals. Recognising and in response to the gold mining industryÆs need for an on-line WAD cyanide measurement device, Mintek recently developed the WAD Cynoprobe. The WAD cyanide analysis technique is based on the use of a ligand exchange reagent that liberates WAD cyanide from metal-cyano complexes. The ligand exchange reaction is represented by the following chemical equation: Metal(CN)X + yLigand <-> Metal(Ligand)y + xCN- The plant filtrate is treated with a ligand exchange reagent, to liberate WAD cyanide, before measuring the free cyanide concentration via amperometry. The instrument proved to be accurate and reliable in the laboratory as well as under industrial gold plant conditions during various trials. It has gained wide-spread commercial acceptance both locally and internationally. However, itÆs recent exposure to complex ore types have called for refinements to the analysis technique. It has been further developed to improve its precision and accuracy and to remove reagent and thiosulfate interferences. Its compatibility with the most commonly used destruction oxidants has also recently been investigated. The WAD Cynoprobe may be configured to measure both free and WAD cyanide concentration. Its fast analysis time, approximately 5 min, makes it suitable for use in the control and optimisation of the cyanide destruction and recovery process. Proper oxidant dosage control and monitoring of effluent concentration levels will ultimately result in less cyanide and post-destruction salts discharged into the environment.

Jan 1, 2008

By C A. Foss, D A. Clark, D Hillan

While magnetic surveys are the most common geophysical method used in mineral exploration, magnetics and geology remain to be fully integrated quantitatively in iron ore provinces. Although high-resolution aeromagnetic data has been collected over prospective areas of the Hamersley Province, much of the information in the data sets has hitherto not been fully exploited due to a lack of suitable interpretation methods. Recent advances in the processing and modelling of magnetics in highly magnetic terrains, constrained inversion and 3D visualisation and understanding the magnetic properties of banded iron formations and iron ores potentially create the capability to generate realistic 3D mapping of magnetite and hematite concentrations over large areas. Initial processing of conventional total magnetic intensity data produces true potential field maps that are unaffected by local perturbations of the regional geomagnetic field direction by intense local anomalies. The true potential field can be converted into vector and tensor components, each of which emphasises different structural features of the geology. Scalar quantities derived from these components simplify interpretation, using new methods, developed by CSIRO and elsewhere, that are less sensitive to magnetisation direction. Preliminary interpretations allow interpolation between mapped units and structures and evaluation of remanence and anisotropy effects. Accurate modelling requires rigourous treatment of self-demagnetisation and magnetic interaction effects. Semi-automated constrained inversion, combining magnetics with available geological information and other geophysical data, can be utilised to generate models of disposition of major magnetic units and the 3D magnetisation distribution within them. The final stage of interpretation is to exploit the understanding of magnetic properties (susceptibility, anisotropy and remanence) developed over many studies by CSIRO, the University of Western Australia and others to convert the interpreted magnetisation distributions into 3D maps of magnetite and hematite contents, which are the quantities of direct exploration interest.CITATION:Clark, D A, Foss, C A, Austin, J and Hillan, D, 2015. Three-dimensional mapping of magnetite and hematite concentrations from reprocessing of detailed aeromagnetic data, in Proceedings Iron Ore 2015, pp 229–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Crushing Plant Process Optimisation Design of processes in order to find the most efficient solution to a specific task is a difficult problem. Often the number of solutions are large and the optimal solution is therefore difficult to identify. Crushing plant process design is no exception from this statement. In order to find the best solution issues like equipment selection and process configuration must be mastered. The solution must both be technically feasible and preferably have a low operating cost. Since crushing plant design is a complex task with a large solution space it is basically impossible to master without a specialised tool. For a long time simulation softwares have been used to assist in the design process. These tools only give answers for how a user defined plant will operate. There are no tools with capabilities to consider different design options in order to determine what the most efficient solution looks like. In this paper a method for crushing plant design optimisation is presented. The novel method utilises a combined optimisation routine and expert system in order to find the most cost efficient solution to a given process task. The user will only need to define the feed material properties, the process capacity, and the end product requirements. The developed system will find the solution lowest production cost per ton.

Sep 13, 2010

Education for the Mineral Industry in Australia developed in an uncoordinated but effective fashion till the mid 1960's, with recognised quality in graduates, with output matching demand, and with industry needs being fulfilled. Then in the space of a further 20 years, as company structures expanded, as the number, complexity, and costs of mineral projects escalated, as educational facilities, costs and politics increased, as community perceptions and aspirations changed, as government control of minerals and education increased, and as mineral sales cycles and markets fluctuated widely, the very fabric of Australian Mineral Education fell in tatters. Extractive Metallurgy Education suffered most in this collapse, and no compre- hensive remedies have been initiated. We are all the losers. In the 1990's, the extraction of Australian minerals and metals will increase in international significance, and the education of Extractive Metallurgists must meet this need. After examining the current situation, a series of management strategies are proposed to enable Extractive Metallurgical Education to survive and prosper in the next two decades and beyond. These strategic proposals involve industry, the government, the educational bodies, and individuals, in a range of short and long term objectives, policies, and actions.

Jan 1, 1984

The Olympic Dam copper/uranium deposit was discovered in 1975 and subsequently commenced production in 1988 at a rate of 1.5 Mtpa using the sublevel open stoping mining method. In the following five years the operation underwent two optimisation programs that have increased mine output to the current rate of 3.4 Mtpa of ore. The pre-expansion requirements were annual development of approximately 10 000 m and the placement of around 500 000 m 3 /yr of cemented backfill. Previous to 1995 all hoisting was carried out by the Whenan shaft. The Robinson shaft was commissioned during that year to hoist increasing development mullock tonnages and to allow for increased ore hoist via the Whenan system. In 1996 WMC committed to expanding the output of the operation from 85 000 tpa (1996/97 budget) copper metal to 200 000tpa. The corresponding increase in mine ore production requires expansion to a nominal rate of 9.0 Mtpa. To achieve these increased tonnages, major hardware installations will include sinking of a third shaft capable of hoisting in excess of 9.5 Mtpa, a rail haulage horizon utilising automatic trains, expansion of the existing backfill plant to a production capacity of over 1.8 million m 3 /yr, increasing long term development rates to 15 000 m/yr and increasing the production drilling and blasting rates in line with the higher stope production output. This paper provides detail into the intended hardware (shafts, equipment, etc) of the mining system, and outlines the intended long-term operation and management of the operation. Of particular note is the background requirement of ensuring existing production targets are met to provide critical cashflows into the project during the period of expansion.

Jan 1, 1998

By D P. Blair

Various analysis techniques are used to determine the nature of a large seismic event that was triggered by a mass blast in an underground mine. This event was recorded by surface accelerometer arrays whose output was doubly integrated using a stable filter to determine the dynamic displacements. The peak dynamic displacements during the blast were 0.09 mm, and during its latter stages, this blast induced a seismic event having a peak dynamic displacement more than ten times larger at 1.26 mm. Polarisation analysis, based on the complex covariance matrix, showed that the seismic event was caused by movement of a known underground fault, close to the blast, which radiated most of its release motion as a shear-horizontal (SH) wave. The change in frequency content with time for the blast and seismic event was initially determined using the Fourier-based reassigned S-method. This analysis showed that the large amplitude seismic event had frequency content significantly lower than that of the blast. Nevertheless, this Fourier technique still retains the problems associated with short time windows as well as the fact that most realistic signals are non-stationary. In order to eliminate such influences, the more recently developed empirical mode decomposition (EMD) was used to obtain the intrinsic mode functions (IMF) of the seismic wave propagation. The EMD vibration analysis showed that each IMF generally exhibited distinct frequency changes throughout the blast and a significant reduction in frequency throughout the subsequent event. It is shown that most of the energy of the seismic event is contained in IMF modes 2, 3 and 4 of the SH wave; the high-frequency first mode (IMF1) contains little energy. Such modal analysis is not possible using standard Fourier methods.CITATION:Blair, D P, 2015. Dynamic displacements from a blast-triggered seismic event, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 203–210 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015