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By Ramsden AR

The ability of the scanning electron microprobe to provide non-destructive qualitative and quantitative mineralogical analysis at the micrometre scale makes it a very versatile tool for the mineralogical characterisation of ore deposits and their host rocks. With the trend towards exploitation of large tonnage low grade depositsnd precious metals at the parts per million level it is becoming increasingly important to have full mineralogical characterisation and knowledge of the mineralogical residence of the valuable elements to assist formulation of a cost-effective exploration program and obtain optimum recovery in the case of exploitation. Mineralogical applications include

Jan 1, 1989

The passage of a vast array of new State and Federal environmental legislation over the last couple of years has required many mine operators to sharpen their focus on environmental requirements. Established requirements, such as environmental impact assessment, minimising disturbance and rehabilitation must now be complemented by mine environmental management plans. These may not only require regular monitoring of mine operations and detailed forward planning to prevent or reduce environmental harm caused during mine operation, but annual updating. It is likely that in future these plans will be required to incorporate general principles such as pollution prevention, sustainable development, waste minimisation and conservation of biodiversity and ecological integrity.

Jan 1, 1993

Geological modelling is a crucial preparatory stage to most facets of the mine planning of an orebody. The process of modelling involves skilled geological interpretation. Recent innovations in computer software and graphics hardware provide many tools which can be used to dramatically improve on manual methods of interpreting orebody data. Geological interpretation can be carried out quickly to produce accurate block models for many orebody attributes, such as grades, and these models can be easily updated locally as exploration and mine development data become available. The speed of the modelling process coupled with the mass storage capabilities of the computer now allows geologists to optimise the geological model or carry more than one model through to the mine planning phase.

Jan 1, 1987

Indonesia remains relatively unexplored by modern methods. The great expectations created by the rush of companies taking up Contracts of Work over large areas during the epithermal gold/ring-of-fire boom (1985-7) have not been fulfilled. This is not necessarily a reflection on the prospectivity of Indonesia; on the contrary, many of the hopeful companies were,, under-staffed and under-financed to overcome the physical and logistic problems of exploring virgin jungle.After the stock market crash of 19th October, 1987, many of the weaker companies were unable to sustain their programs or to arrange farm-outs, and they have subsequently relinquished their tenements. In some cases, little or no field work has been carried out so that many areas remain untested. This poor performance will ensure much more rigorous scrutiny of future applications by the Indonesian authorities.

Jan 1, 1990

Exceptionally weak ground, usually associated with faulting, unanticipated groundwater pressures or flows and exceptionally high stress concentrations are some of the hazards which confront the underground excavation engineer. One or more of these hazards can seriously delay or even halt a tunnel or mining project, and methods for predicting these hazards are urgently required, particularly for projects involving high speed drill and blast or tunnelling machine excavations.This paper explores the current availability and the potential for the development of tools and techniques for the prediction of these hazards. It is concluded that systematic and automated geological data collection and interpretation represent the most promising avenue for development. It is suggested that there is room for the use of expert systems in which the computer is used to assemble and organize practical underground excavation experience into an interactive decision making system.

Jan 1, 1985

The accurate calculation of ore reserves is one of the most important functions under- taken at a potential or operating mine. In recent years there has been a trend towards recommending more and more complex techniques for the calculation of reserves. However these are not always necessary and many improvements could be made by the use of all potential data and a heavier geological input. An ore reserve should be the result of geological not mathe- matical or engineering reasoning. All ore reserve estimates are wrong and the important thing is to.recognise why they-are wrong and to take action to minimize the errors. Geostatistics and other complex mathematical techniques may appear to answer all our needs for ore reserve accuracy but there are many drawbacks, not least of which is the communi- cation gap which may develop between the operator and both management and production Personnel.

Jan 1, 1979

In November, 1967, a four strand curved mould continuous casting machine coupled with a 50 ton basic oxygen furnace began producing billets for the rod mill and new merchant mill at the Newcastle Steelworks. To date over 500,000 tons of carbon and alloy steels have been cast at the rate of 20,000 tons per month, the major part for the wire industry. Many alterations have been made to the plant to simplify the process, improve quality and increase production. Casting parameters have been developed for each different type of steel. The quality of the final product has been influenced most by casting temperature, secondary cooling and casting speed. All these factors have been controlled and good results are reproduced. More exacting requirements of liquid steel quality have brought about the use of higher lime/silica ratio slags during steelmaking to control phosphorus revers- ions and standard ladle additions of manganese suicide and ferro aluminium for more effective deoxidation.

Jan 1, 1972

The scope, pace and depth of mining is creating a need for improved ground control strategies to meet mine safety standards. Ground control and associated conservation problems relating to subsidence and the disposal of mining and metallurgical wastes can be resolved by mine filling with selected reject materials. The lack of suitable criteria to evaluate the applicability of such materials and especially cemented forms of fill is considered. Sulphide wastes, which are prone to oxidize, and cement are inexpensive mine fills, but their incorrect use can give rise to problems which are briefly described. Research work concerned with the utilization of sulphide wastes such as mill tailings, to produce fill with self-cementing properties has shown that the development of cohesion and strength is attributable to natural oxidation processes controlled by the physical and chemical composition of the fill mass. The cementing is caused by a number of oxidation products, and is most effective when the mineral pyrrhotite is present. The concepts of fill design are outlined and various criteria for assessing durability and deformational properties are proposed. Specimens prepared in the laboratory are capable of attaining unconfined compressive strengths up to 28 MN/m2.

Jan 1, 1973

A resource rent taxation scheme is based on the concept of taxing the rent or surplus profit generated from primary industry activity. Rent has been defined as profits that remain after deduction of company income which corresponds to the minimum return necessary to attract private investment to a new project.Rent taxation schemes on the mining industry within the Australasian region have been examined and widely discussed during the decades of the 1970s and 1980s. Forms of resource rent taxation schemes have been imposed on Papua New Guinea mining, some sectors of Australian petroleum, the Roxby Downs venture and are being discussed for the New South Wales coal industry. While no introduced applications have been pure rent taxation schemes, the concept has generally come to encompass arrangements which tax rent at a partial rate which may or may not vary with the level of profitability or return.An examination is made of a number of the more recent schemes. Aspects which should be considered in implementation of new forms of this taxation are discussed. It is concluded that there is an increased acceptance for this form of taxation on the Australian mining industry.

Jan 1, 1990

A thousand writers have harped upon the wondrous nature of the inventive faculty. They realise that man is a creator, and that capital and labour alike are, and will always be impotent without machinery and processes that is invention. What Bacon has said is echoed by them all, "the introduction of new inventions seemeth to be the very chiefest of human actions. The benefit of new inventions may extend to all mankind-they make all men happy without injury to 'any' they are new creations and imitations of God's own works." My remarks will occupy another field I will refer to some of those features of the Patent Laws of different countries, which prevent the use of new inventions, oppress the development or inventive' genius, and diminish human happiness and progress' Wherever Patent Laws are framed and administered upon wrong principles, these results are inevitably found. A concise, complete, common-sense comparison of the chief Patent Laws of the world cannot easily be found but to avoid seeing scrappy, misleading references to Patent Law in the press particularly the English-would be equally difficult. Writers who are considered authorities so frequently make minor issues prominent and so uniformly fail to give weight to fundamental principles that the effect on the public is to mislead.

Jan 1, 2004

By Markic S, Subelj A

Long-term plan for lignite mine Velenje has been made by using technical parametrisation method where the basis for periodical, middle- term and short-term plans as well as for scheduling has been already fixed. For a certain time period a plan

Jan 1, 1998

Although the title of this paper permits a very broad scope for discussion, I propose to deal mainly with those aspects of design part- icularly related to rook filling, the'theme of this conference. The unique suitability of belt conveyors for the continuous economical delivery of materials into or out of underground workings, is well established and needs no elaboration. The facility with which conveyor units, comprised of modern modular components, can be adjusted to lengthen or shorten, their ability to be readily repositioned to suit the develop- ment of a work pattern and their virtues as low noise, reliable transport media, are already accepted by all who are involved with the mining industry.

Jan 1, 1973

By Pollard P. J

Australia is well endowed with both tin and tungsten resources, and is currently a significant producer of both commodities for the international market. The intensity of exploration activity for both metals has been rather sporadic, reflecting the changing market situation. Thus tin has experienced three major boom periods around 1880, 1907 and 1983, while tungsten prices peaked around 1917, 1953, 1970 and 1977. During the earlier periods, the major discoveries were located utilising simple prospecting techniques involving creek travers- ing and stream sediment panning. The resulting location of tin alluvials quickly led to the discovery of adjacent primary deposits. The major tungsten deposits were composed of quartz- wolframite, which was readily visible as mineralised float both within the drainage systems and on scree slopes. Thus by the early 1900s most of the currently significant deposits had been located. More recent exploration approaches have combined these tradi- tional methods with the development of exploration models based on evolving genetic concepts. Within tin systems the emergence of province styles of clas- sification combined with enhanced perceptions of tonnage-grade characteristics and improved geological models has enabled more effective exploration strategies. Province classification at the inter- national scale demonstrated a clear relationship between deposit type and geological environment and thus considerable attention was given to the range of provinces present within Australia. Tonnage-grade diagrams enabled the refinement of economic per- spectives, while detailed models provided the basis for localised search parameters.

Jan 1, 1988

The Antarctic Peninsula consists of accretion complex sedimentary and volcanic rocks, talc-alkaline magmatic are rocks, marginal basin sediments and extension-related alkali basalts, dominantly of Mesozoic to Cenozoic age. Metallic minerals have been recorded at "250 localities but two thirds of these are innocuous occurrences of Fe+Cu accessory minerals. The remaining -70 localities are related to hydrothermal mineralization processes. Metallogenetic associations identified are: vein and breccia-hosted Fe+Cu+Zn+Pb+Mo or Fe+Cu+Mo+Mn, shear-hosted Fe+Cu, volcanogenic Fe+Cu and pegmatite-hosted Fe+Cu+Mo+Mn. Anomalous Au, Ag, As, W and Sb also occur but are not of economic interest. Metallogenic zoning is unproven and genetic models are uncertain, possibly involving volcanogenic, epithermal to hypothermal vein and porphyry-type systems. Substantial field and laboratory studies are required to understand distribution and Genesis.

Jan 1, 1987

By Beattie MJV

Widely diverse mechanisms exist for the action of a range of selective sulphide flotation depressants. Collector desorp- tion, leaching, competitive adsorption, formation of hydrophilic reaction-product coatings, action as reducing agents, and action as lattice-oxidizing agents are discussed. Detailed attention is focused on the latter two mechanisms. Recent works on copper depressants particularly for copper-molybdenum separations, and oxidizing agents enabling arsenopyrite- pyrite separations, are presented and discussed.

Jan 1, 1984

By Rozman L. I

This paper describes the latest open pit optimisation techniques,which now go beyond merely finding an optimal outline. The paper starts by briefly reviewing pit design techniques before optimsation. It then goes on to describe the pit optimisation procedure and the extensions to it which allow the automatic generation of nested families of pits. Next, the properties of families of nested pits are examined and the paper explains how they can be used to simulate certain mining sequences and schedules. Finally, we describe an actual study which was done using this kind of Software.

Jan 1, 1991

By Singh T, Singh D. P

India has limited resources of coking coal. Most of the coking coal seams are located in Jharia Coalfield. These seams were worked in the past by the bord and pillar system in a haphazard manner, which has resulted in honeycombs of old working. Most of such areas are under fire. In order to meet the demand of coking coal in the 21st century, it is essential that the coal locked due to old underground workings is recovered fully by conducting opencast mining to an ultimate depth of 500 m. The major problem envisaged in conducting opencast mining in such areas will be the stability of pit slopes over voids and the behaviour of subsided material in the pit slopes. An attempt has been made to simulate this complex situation from a specific section of the rockmass of a mine in an equivalent material (EM) model. The old workings existing in upper coal seam (V) were simulated by developing staggered bord and pillar workings in two sections and depillaring them. Opencast mining was conducted for recovery of coal locked due to irregular working in coal seam V. The slope instability caused by intersection of the slope with the void, during frontal working (by shovel-dumper combination) was observed in various situations. In this paper, the technique adopted for simulation of a 125 m thick section of rockmass in an EM model is outlined. Adverse effects of staggered workings and

Jan 1, 1988

By K H. Esbensen, A Arkenbout

In the north of the Netherlands, in the environment of Harlingen, an industrial waste incinerator was installed in 2011. The population in the region is concerned about adverse health effects related to possible emission of dioxins. This study compares the relative merit and reliability of four sampling approaches aimed at quantifying the possible pollution patterns surrounding the incinerator: short-term versus long-term isokinetic flue gas sampling, spatial sampling of grasses and a novel approach developed by the Toxicowatch Foundation, based on local composite sampling of ten eggs from backyard chickens (local area pollution load averaging by accumulating bio-entities). Based on the latter approach results of a new analytical bioassay, DR CALUX®, from 15 locations near Harlingen harbour show distinct above-threshold dioxin levels in the environs of the incinerator. Currently only short-term flue gas sampling is mandated by the authorities; based hereupon, under normal operating conditions, the incinerator appears to be compliant with emission standards. This short-term sampling scheme is seriously flawed, however, in that it only demands one continuous 12-hour sampling period per annum – an extreme grab sampling transgression in the time domain. In starkest possible contrast, significantly elevated dioxins emissions were measured in flue gas during events of unstable combustion conditions by continuous long-term measurements. The dioxin congener patterns from long-term flue gas sampling show similar patterns as the congeners found in backyard chicken eggs and grass, evidence that elevated dioxins in eggs is due to emissions from the incinerator. These results make it mandatory to perform long-term, continuous measurements for all sources where similar high-temperature combustion/emission processes take place. Backyard chicken eggs are a prevalent regional bio-accumulating sample type in rural and agricultural regions, which is relevant to air pollution emission monitoring. There are interesting relationships between this type of sampling bio-sensors and the special bioassay DR CALUX® features, which, although quite outside traditional contexts, never-the-less all can be well understood in the context of the Theory of Sampling. We venture to unravel the complex interactions between correct and incorrect sampling errors and the extraordinary complicated analytical issues involved in monitoring and source tracking using accumulating bio-sensors. The present contribution is but a first foray indicating the general total sample error scope and total analytical error framework needed for this approach.CITATION:Arkenbout, A and Esbensen, K H, 2017. Sampling, monitoring and source tracking of dioxins in the environment of an incinerator in the Netherlands, in Proceedings Eighth World Conference on Sampling and Blending , pp 117–124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By H Zhang, A Lawrence

To accommodate the fast growing need for services in Singapore’s Marina Bay downtown area, Marina South, the construction of a common services tunnel (CST) was required. The CST includes various services such as telecom cables, power lines and water pipes. A deep excavation and temporary earth retaining system (TERS) was required to facilitate the construction of the tunnels. Marina Bay is reclaimed land over thick soft marine clay which is likely to be still consolidating. The deep soft marine clay poses a big challenge for deep excavations in downtown areas where highways and sensitive structures are close by. This paper presents a case study of part of the CST Phase 1B and 2 at Marina South, in particular a 26 m deep excavation supported by a 46 m diameter temporary caisson. The construction started in late 2006 and the basic structure was completed in early 2011. The caisson was formed by 1.0 m thick overlapping diaphragm wall panels with a capping beam and three ring beams at different depths. Two-dimensional finite element analyses were conducted to predict the ground settlement, lateral displacement, bending moment and hoop stresses in the diaphragm wall and ring beams during different excavation stages. A comprehensive instrumentation and monitoring scheme was established to verify the design predictions, control excavation safety and trigger the contingency plan to protect public safety. The impact of construction activity, unbalanced temporary stockpiles and adjacent deep excavation for a mole removal will be discussed.CITATION:Zhang, H and Lawrence, A, 2014. A case history of a deep excavation in a big circular shaft in Singapore marine clay, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 581–588 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014