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`WELL HE WOULD, WOULDN'T HE?' Public Relations people have something in common with advertising people and politicians: there exists a perception that their whole Raison d'Etre is to create, mould, and maintain images which are far removed from reality

Jan 1, 1994

By Fountain C. R

In April 1987, Mount Isa Mines Limited (MIM) commissioned an ISASMELT reactor to smelt 15t/h of copper concentrate at the Mount Isa Copper Smelter. This unit was based on the Sirosmelt lance technology and incorporated features proven in the Lead ISASMELT plant which has been operating in the MIM Lead Smelter since 1983. From April 1987 to June 1989, the copper smelting plant treated 167000 tonnes. Concentrate, coal and fluxes are fed continuously to the furnace. Oxygen enriched air is injected through a lance which is submerged in the slag bath. Matte and slag are tapped together through a single taphole into a reverberatory furnace, and from there are treated with normal reverberatory furnace production. Advantages of the process include its ability to eliminate most lead and arsenic in feed, its flexibility with respect to feed composition, sizing and moisture, and the plant's low capital cost. Acceptable refractory life has also been demonstrated. The commissioning of a 70 t/day oxygen plant has rerated the plant from 15t/h to 18t/h while allowing a reduction in fuel usage of one third. A trial using 150 t/day oxygen was carried out in May 1989, and showed that the furnace could treat 48 t/h chalcopyrite concentrate while maintaining a very low fuel requirement. The oxygen trial results have given considerable confidence for plant scale-up. Detailed project evaluation is currently underway for the replacement of the roaster and reverberatory furnaces at Mount Isa with a single 110 t/h ISASMELT reactor.

Jan 1, 1989

By E Hernandez, I Agustian, W Kusumohastuti

PT Freeport Indonesia is completing the first underground gyratory crusher excavation at their Deep Mill Level Zone (DMLZ) mine located in the mountains of Jayawijaya, District of West Papua, Indonesia. DMLZ is an underground block cave mine with an expected output of 80 000?t/d and a scheduled production start in 2015.In order to deliver crushed ore to the mill through the existing conveyor belt, the DMLZ block cave mine will construct two 1000?kW 1.6?×?2.3?m gyratory crushers with their own respective ore flow conveying systems underground. Each crusher is composed of top, middle, and bottom chambers with an ore bin. This system includes a series of high capacity conveyors approximately 5 km in length including transfer stations and support facilities.The development methodology required a combination of lateral development by jumbo drilling machines and vertical development by mechanised raise climbers (MRC) due to the complexity of the chamber design.This paper will discuss the project scope, design and development methodology, ground conditions, innovative survey controls, and the challenges faced due to the remote location.CITATION:Hernandez, E, Kusumohastuti, W and Agustian, I, 2014. Excavating the first underground Gyratory Crusher at the Deep Mill Level Zone mine, PT Freeport Indonesia, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 43–50 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

Industrial minerals and rocks (alternat ively called non-metallic minerals) are those- which are economically important because of their desirable physical or chemical properties rather than their metal or energy content. They are divided into nine classes: structural, pig- ments, process aids, ceramics and refractories, chemical source minerals, abrasives, foundry minerals, gem stones, electrical minerals. Development of deposits is influenced by the dominance of marketing,by the required range of products, the-need for specialized process- ing, place value, and the transportation and distribution of high-bulk, low-cost commodities. Evaluation is different from that of base metals because of differences in geological occurrence, sampling methods, testing, treatment, placing a money-value on the material and the importance of export markets.

Jan 1, 1973

Esso-BHP have installed a production supervisory control system that is presently controlling the offshore oil and gas facilities on the Barracouta and Marlin platforms from an onshore master station. This control is achieved with a computerized master station onshore which uses a UHF radio system for telemetry and control.The system is designed to control, monitor, and gather data from a large number of oil and gas production platforms and has flexibility to handle future variations in operating conditions.The system will be extended to the Halibut platform late in 1970 and to the Kirlgfish platforms during 1971.

Jan 1, 1971

By N R. Johnson

The overland conveyor at the Los Pelambres mine in Chile is designed to move 8700 t/h of material over 12 km at a speed of 6 m/s while descending 1400 m. The conveyor, which is divided into three segments, is equipped with a braking system that must bring it to rest without producing excessive stresses in the conveyor belt. Retardation and gently stopping a mass of 250 t requires retardation times in the order of 60 seconds. Brakes that can provide this performance require sophisticated controls as well as very high heat absorption capacity. This paper describes the thermal analysis of the braking system, which required the use of novel materials to meet the arduous duties imposed on the callipers and discs.

Jan 1, 2005

Digital Simulation of Particulate Processes The inherent complexity of mineral particulates (shape, size and mineralogical texture) has challenged conventional simulation model approaches for decades. Much effort was expedited in using mathematical assumptions to accommodate stereological effect. With the advance of instrumental methods such as x-ray microtomography 3D structure can, in many cases, be measured directly. The information derived from such measurements provides direct input to building the structural digital model. In addition digital simulation methods that enable creation of process realistic particulate properties in an efficient digital computer space have demonstrated their effectiveness to model a variety of realistic packing, sorting and multi-phase processes. The paper reviews recent advances in the use of information derived from 3D micro-tomographic imaging and laser scanning technology can be coupled with digital methods to enable simulation of tablet compaction and dissolution, filtration and permeability, column packing and leaching kinetics, packing and cementation of nuclear waste. By assigning 'properties' to a digital zone (voxel) in the computational space it is possible to mimic the realistic characteristics of quite complex particulate mineral processing systems. The system self-adapts to correct the coherent particle characteristics (shape, size, compound, porosity) with time. Such simulations are useful to elucidate the sensitivity of system performance to variations in process parameters. Dimensional scaling of the approach is also possible, as the case studies will illustrate, in deploying the method to both small (micron) and large (m) features. The use of process realistic simulations presents experimental challenges in code validation. It is in this context that other tomographic methods play a role in direct 3D measurement of system behaviour such as electrical and optical sensors.

Sep 13, 2010

W. Johnson (Consultant, Adelaide) : Is there any mineralogical evidence of temperature of formation of the amphiboles and other minerals present in the crocidolite veins and country rocks7.N. A. Trueman: I am not aware of any definite evidence of the temperature of formation of these minerals, but am of the opinion that high temperatures would not be present during crystallization.No evidence from the qUl'trtz, magnetite and hematite of formation temperatures is indicated and, as the carbonate is later than the other minerals it does not supply any data either.According to Miyashiro and other workers who have studied the composition and stability of the glaucophaneriebeckite series, minerals of riebeckite composition are stable over a wide range of P, T conditions. Recent work by W. G. Ernst, of the University of California, indicate that, in the presence of an Fe203/Fe304 buffer, riebeckite and crocidolite are more likely to form at low temperatures. The occurrence of riebeckite-crocidolite as authigenic minerals has been reported from several localities.Dr. MacLeod (Geol. Surv. of W. A.): Recent regional mapping by the Geological Survey of Western Australia has revealed a total thickness of at least 30,000 ft for the Proterozoic sediments in the Hamersley Basin. In this succession the asbestos-bearing beds of the Brockman Iron Formation at Wittenoom are overlain by some 20,000 ft of younger sediments and volcanics. With such a thickness of superincumbent material, it seems perfectly valid to involve

Jan 1, 1963

By B Dunstan, F Wirfiyata

PT Newmont Nusa Tenggara (PTNNT) operates the Batu Hijau copper and gold mine and process plant on the island of Sumbawa, Nusa Tenggara (Barat)  NTB, Indonesia. The plant consists of a nominal capacity 120 000 t/d conventional semi-autogenous ball milling crushing (SABC) circuit followed by sulfide flotation to produce a bulk copper concentrate for sale. Process control is effected by a plant wide distributed control system that overlays an extensive integrated programable logic controller (PLC) framework. The system is enhanced by a supervisory expert control system.Since plant commissioning in September 1999, over US$4 million has been expended as part of a systematic continuous improvement approach to optimise plant control performance. Works completed to date include: redesign and upgrade of architecture of the control system to ensure long-term system reliability, security and upgradeability and to provide a suitable platform for advanced control; integration of supervisory and advanced control tools, techniques and instrumentation; and implementation of sound network communication and plant data reporting tools. This paper outlines the evolution of process control and associated systems and tools that contribute to successful operation and ongoing performance optimisation at Batu Hijau.

Jan 1, 2009

The major copper orebody at Mount Isa is being extracted at a rate of four million tonnes per year. The method used requires an equivalent rate of back filling with (mainly) cemented fill. There were three major incentives for developing this mining system. The first was the prospect of high ultimate recovery of the orebody. The target is 100 per cent recovery. Also the proposed stoping layout appeared to offer significant advantages in development and production costs. Finally, extensive subsidence above the northern end of the orebody could have disturbed permanent surface installations and jeopardised a possible future open cut. The full implications of this ambitious strategy were not apparent in the early years. Now, after 12 years of production the benefits are being realised and they can be weighed against the costs. Probably the most interesting result which comes from this analysis is the significance of cutoff grades and dilution factors in balancing mining and filling rates.

Jan 1, 1980

Cut and fillstoping using hydraulically placed mill tailings has become an essential feature of stoping operations in Kalgoorlie. ' Approximately 30 per cent of the total production is currently mined by this method. Fill is prepared by thickening or cycloning and is gravitated or pumped underground. The average pulp density is 70 per cent solids by weight, Recent cost reducing innovations are the use of steel passes, corrugated iron manways, polythene film sealing, and the replacing of vertical cement lined pipes with boreholes. TTTTTI rvr T Trim r l1TT

Jan 1, 1964

By H Nikraz, E Jamieson, D Cooling

The use of red sand as fine aggregate in concrete manufacture has been investigated as well as the use of fly ash as a cement replacement. The experimental work consisted of casting various concrete mixes including a control and comparing standard properties. Properties tested included compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, water permeability, chloride diffusion, pH dependence leaching and particle morphology. The results show that the concrete strength is not significantly affected when natural sand is replaced completely with red sand. The durability tests indicated high water permeability and high chloride diffusion due to the porosity of the red sand concrete, likely due to the low slump value. Leaching tests did not exceed New South Wales EPA guidelines.

Jan 1, 2006

The Karangahake gold-silver deposit is located 11 km west of Waihi in the southern part of the Hauraki Goldfield. Historically it was the second largest bullion producer in the goldfield with a past production (1882 - 1944) of 126.712 tonnes of gold-silver bullion (Au:Ag ratio of 1:3.3) from 1 142 315 tonnes of ore grading 27.4 g/tonne gold equivalents.

Jan 1, 1987

By Payne AR

The high cost of gateroad repairs and maintenance in U.K. longwall coalmining is a clear indication of the failure of permanent support systems to fulfill their prime function, i.e. control of strata movement. The main component of gateroad support is the pack, the design and materials of which have experienced an important development process during the last 10-15 years. More recently, research investigators have attempted to give a design basis to pack quality and dimension, and reference is made to two theoretical approaches. In the course of a current research programme based upon in situ monitoring, interim design recommendations have been proposed as a means of effecting improvement in support efficiency. Identification of characteristic deformation behaviour forms the basis of the recommendations made and the subsequent improvement in gateroad performance reported.

Jan 1, 1986

China has abundant bauxite resources, but these resources are mostly of a diaspore, which has a feature of low Al2O3 to SiO2 mass ratio, typically ranging from four to six. Compared to other materials, this kind of raw materials consumes more alkaline and energy in the process of metallurgy, and incurred a high alumina production cost. To solve this problem, researchers in China have done a lot of work on removing of the silicon from bauxite. Under the impetus of these works, in 2003, the first flotation plant of diasporic bauxite in the world was constructed in Zhongzhou, Henan, China. Seven years of operating experience shows that this technology can signifi cantly reduce the costs of following-metallurgy processing. These efforts are an important reference for the processing of similar resource. In general, for Western scholars it is diffi cult to fully understand these works because most of them are published in Chinese. In this paper, a detail introduction for the research progress on China bauxite de-silica flotation was presented, these works involved crystal chemistry, wettability of bauxite minerals, collector and modifi er in bauxite fl otation and flotation practice, etc.

Sep 13, 2010

Exploration risk increases with time, due to a general decrease in prospectivity as the more accessible deposits are found, and be- cause of rising costs and demands due to an improving standard of living. Risk is separated into financial risk, which increases sharply at the development stage, and the risk of failure which is at its peak at the outset of exploration. Risk is also divided into internal and external factors; some of the latter cannot be offset, viz. the systematic overall risk for any enterprise. The recently emergent risk embodied in withdrawal of large areas from exploration access is discussed. An appeal is made for objective multiple land-use policies to be applied so that land remains available at reasonable cost and with appropriate environ- mental safeguard conditions. Risks specific to gold exploration are discussed. As gold now accounts for over 50% of all mineral exploration, and most other metals are depressed, any sharp decline in gold will have grave effects on the ex- ploration industry. Gold exploration will become more difficult and expensive in about five years, after most of the readily accessible deposits in Australia are found. Government's role is important in pro- viding stability and basic data at reasonable cost. Exploration for specific minerals or of particular areas could be stimulated by extending the 150%.tax deductibility of R & D to aspects of exploration of strategic im- portance, particularly in the event of a downturn. Exploration is classic scientific research, at least through to the proving Stages.

Jan 1, 1987

By G R. Hancock, S Grant, T Whiteside, J B. C Lowry, J Boyden, T J. Coulthard

Physically-based landform evolution models (LEM) provide a spatial framework to forecast the long-term geomorphic stability of post-mining landscapes. When used to test the relative stability of different landform designs, LEMs may assist with the development of optimal closure designs for rehabilitated mines. However, in order to reduce prediction error, factors controlling landscape evolution must also be accurately represented by models. This requires that the correct sets of processes are represented and that driving parameters used in LEMs are, if necessary, calibrated to the landscape of interest.Vegetation exerts strong controls on the hydrologic and geomorphic processes that drive landscape evolution. Hence, the spatial and temporal scales over which typical patterns in vegetation are represented in different landscapes are important considerations in LEM calibration. However, vegetation is rarely accounted for in LEMs and even when integrated is often represented simply, without representing spatial dynamics of vegetation cover that may impact landform development.This study focuses on characterising vegetation patterns to calibrate a new vegetation module of the The Cellular Automaton Evolutionary Slope and River (CAESAR)-Lisflood LEM to be applied to a conceptual rehabilitated landform of the Ranger uranium mine located in the Alligator Rivers Region (ARR) of northern Australia. In the ARR the spatial dynamics of vegetation over time are largely driven by monsoonal rains and topography. Extensive dry season fires are also common in the region, temporarily reducing vegetation cover where they occur. Hence, hydrology, topography and fire disturbance interact to shape a distinct, yet dynamic, mosaic of different vegetation types of varying cover density. As a basis for calibrating the new vegetation function, the distribution and dynamics of vegetation are characterised for this savannah landscape by remote sensing, in conjunction with ground data.CITATION:Boyden, J, Lowry, J, Coulthard, T, Whiteside, T, Hancock, G and Grant, S, 2016. Accounting for vegetation dynamics in landform evolution modelling, in Proceedings Life-of-Mine 2016 Conference , pp 63–66 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Large RR

Underlying the 15 million tonne, high grade Hellyer volcanogenic massive sulphide deposit of western Tasmania is an extensive, well developed, and well preserved stringer system. Pervasive alteration of the footwall mafic volcanics occurred as the hydrothermal system initiated. Mineralogical zoning exists within the footwall alteration pipe, with a central siliceous core giving way to zones of chlorite, chlorite-carbonate, sericite-chlorite, and finally sericite-quartz on the margins (stringer envelope zone). However, the alteration morphology and zonation is not symmetrical around the central siliceous core; eastward the alteration zones are steeply dipping and terminate abruptly under the massive sulphide, while westward they extend out under the ore body in a blanket fashion. Geologic evidence indicates that the pervasive alteration started with the development of sericite-quartz which was subsequently overprinted by chlorite and finally quartz-sericite as the hydrothermal system became focused towards the centre of the stringer system.

Jan 1, 1990

Blasting is at first sight a simple operation. Blastholes are drilled in a suitable pattern, primed, charged with explosives, stemmed and finally the blastholes are connected together to give the appro- priate initiation sequence. In practice the action of the explosive takes place in the interior of an opaque rock mass and only the external faces of the rock mass to be blasted can be easily observed. The mechanisms of blasting cannot be observed directly and must be inferred from observations of the free face and meas- urements of particle movement made by sensors grouted into holes in the rock. Explosives react very rapidly, in some microse- conds and any instrumentation of a blast must have an appro- priate response time. In many mines several rock types can be encountered during production. Several different methods of blasting may be necessary to cope with changes in rock types espe- cially if weak rocks are found in the final limits. This also makes it difficult to be sure of getting a large enough volume of rock to perform a series of reproducible experiments. While there appears to be agreement on the mechanism of blasting it is unlikely that a detailed understanding of how all the variables that can be encountered in practice affect blasting. The ease of assessment of the results of blasting depends on the criteria used. It is easy to isolate, measure and count over- size boulders. It is however difficult and costly to get a complete fragment size distribution. Methods used to assess blasting can vary significantly from site to site and the ways in which data are collected, presented and analysed will vary making compari- son of blasts at several locations very difficult. The definition of an optimum blast can also vary with the type of blasting. The muck-pile profile and fragmentation will be different for a dragline to that for a truck and shovel operation. In order to be able to assess blasting the mechanism has to be understood. Th rock and explosive properties considered rele- vant to blasting can then be determined. This paper discusses the generally accepted mechanism of blasting. The on-site observa- tions to assess blasting are-then listed. The mechanism of blast- ing can also be modelled and the use of modelling to optimize hlaetina ie thPn Aiernccarl

Jan 1, 1988

Electronic detonators bring a fundamental and radical change to the potential of rockbreaking operations. The immense technical challenge of safely merging electronic systems with explosives has been largely overcome, but a surprisingly difficult obstacle has been to convert users to the much more capable electronic systems, in routine as opposed to exotic applications. Unit cost is probably the main point of resistance. For years papers have confirmed significant improvements in blasting results, feeding through to enhanced bottom line value for the whole operation: much reduced environmental impact, and improved control over fragmentation, muckpile shape and overbreak. In Africa, a number of operations have been employing the technology for sufficient time to see enduring improvements in throughput, control and cost structure, and these improvements have fed through to the planning process: both the cost and the benefits are part of the plan. This has essentially rendered very unattractive the option of reverting to pyrotechnic systems and incurring the penalties previously unseen but now understood to be avoidable. Examples given are of improved throughput at opencast and underground mines, and greatly extended life at an urban quarry. The general experience of management in implementing the technology is that it over-delivers: adopted to solve one particular problem, significant other issues are also addressed. These extra benefits were quite logical, but not at all obvious prior to implementation. Exploring this reality is essential for harvesting the benefits of the technology sooner rather than later.

Jan 1, 2004