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Depressed prices for minerals will force the mining industry to became more efficient. The continuous conveying of pit product is one area in which savings can be made. Conveyors are available, or can be adapted to provide the flexibility and reliability required. Each conveying system will need to be custom designed to suit the particular requirements of the mine. The Australian mining industry must take the initiative and accept the challenge of the new technology.

Jan 1, 1986

By Baoqi S, Zhengbing C, Wenguang L

A new flotation method is introduced for separating zircon from rutile and other Ti-bearing minerals at normal temperature, using a mixture of cationic and anionic collectors without any acid, alkali or fluoride as regulators. By combining the method with gravity concentration and magnetic separation to process the seabeach placer, the technological flowsheet can be simplified and the pollution of environment and the corrosion of acids, alkalis and fluorides on equipment can be removed.

Jan 1, 1993

By Muge F, Pereira H

In the early stages of the planning of a new exploitation, the error in ore reserve estimation is an important factor that must not be disregarded. As this error can be computed by geostatistical methods, the risk of the venture can be calculated for different recognition patterns in a certain assumption of economical conditions. A case story is described for an open pit phosphate deposit in which grade/tonnage curves and their confidence intervals are related to an economic function for three drilling patterns and decisions are taken on the basis of cost and value of supplementary information.

Jan 1, 1977

Currently there are in excess of 200 companies listed on the New Zealand Stock Exchange and the total market value of all the listed shares amounts to $4.6 billion. The number of listed mining companies stands at nine and with a market value of $35 million accounts for less than one per cent of the total market capitalisation. In comparison, the Australian mining and energy sectors account for nearly 50 per cent of the total market capitalisation, which currently exceeds A$41 billion. Surprisingly the share markets in both countries were primarily founded on the discoveries of minerals last century.

Jan 1, 1982

By van Eck M, Orr T, Eggleton R. A, Taylor G

The Charters Towers locality has been a historically renowned gold producing region and discovery of new ore deposits during the past decade have renewed exploration interests in the area. Further mineral exploration with conventional techniques is hindered by the presence of Cainozoic sedimentary deposits and volcanic flows overlying a major portion of the basement geology. Mineral exploration thus warrants new, innovative and cost-effective methods to probe beneath the Cainozoic cover in an attempt to discover new orebodies. There is growing awareness of the role of weathering as an agent of chemical dispersion into the cover sediments as well as a producer of supergene deposits in tectonically stable cratons (Butt and Zeegers, 1992). Consequently, landscape evolution coupled with regolith geochemistry is one of the methods increasingly being used to identify relevant sampling media to explore beneath weathered cover sediments and deeply weathered bedrock terrain (Anand, 1993). The aim of this paper is to describe and elucidate the regolith - landscape features of the region and combine geochemistry to assess the pertinence of the same on mineral exploration strategies in the Charters Towers area.

Jan 1, 1997

By A S. Lund

Optimisation of the underground mining production process benefits from informed decision making during the process of explosive rock fragmentation. Selection of the most appropriate bulk explosive products for underground production blasting is an area of endeavour that offers significant economic upside if correctly and thoroughly undertaken. The explosive selection process is facilitated by a clear understanding of:the physical and detonic properties of the alternative explosive options available; the response of different rock masses to these different explosive options; and the importance of maintaining a clear focus on desirable blast outcomes in order to enhance value creation aspects of the mining production process. The level of understanding of these issues is raised through the application of measurement and modelling technology, quantifying the effects of blast design (and implementation) on process outcomes. Homestake Darlot and DynoConsult applied a range of dynamic blast measurement and outcome modelling techniques in order to explore the relationship between rock properties, explosive properties and mining process efficiencies. A campaign of vibration and explosive Velocity of Detonation (VoD) measurement produced feed data for use in vibration and fragmentation modelling during the extraction of one of the major stoping blocks at Darlot Gold Mine. The paper describes the use of these tools and discusses the understanding gained concerning the limitations and capabilities of, and the reconciliation between, a selection of analysis and modelling approaches.

Jan 1, 2001

By Monette J. C, Nulty J. H

High temperatures and pressures are required to obtain acceptable stripping rates. Higher chemically induced stripping rates could reduce the need for higher temperatures which lead to cyanide losses. The higher rates could lead to lower carbon inventories and higher gold production. This paper reports laboratory and continuous test unit data which strongly suggest that the preceding can be achieved. New stripping agents demonstrate efficient stripping under conditions of cyanide depletion such as after carbon acid washing. Stripping times for gold and silver can be reduced by at least half compared to caustic cyanide through the use of these novel substances.

Jan 1, 1991

The Key Centre for Mines consists of the School of Mines of the University of New South Wales and the Departments of Geology and Civil and Mining Engineering of Wollongong University. The Key Centre for Mines/International promotes, markets and develops overseas activities in applied geology, mining engineering, mineral processing and extractive metallurgy specifically in response to the perceived needs in the region for mineral resource and other related earth-science based development. the Key Centre for Mines/International will be involved in the overseas marketing of formal courses; special training activities such as short courses and in-house programs; technical and educational consultancy; research and development projects, and in the establishment of regional links through twinning, exchange and various network arrangements with other organisations in the region. Activities which are now being developed include a training program for Korean mining engineers and geologists, teaching and curriculum development in the Mineral Resources Engineering Faculty of the University Sains Malaysia and a staff development proposal for the Department of Geotechnology of Khon Kaen University, Thailand

Jan 1, 1990

By Noakes M. J

Research and development into alternate gold and precious metals adsorbents has resulted in the development of a new technology named the AUROSAVE adsorption process (ARGOSAVE'" for high silver con- tent ores). Adsorbents called VITROKELE'" can be tailored for either Gold I (cyanide leach) or Gold III (halide leach) applications. VITROKELE consists of a chemically synthetic adsorbent carried on an inert substrate, often a polystyrene bead. It is suitable for both in- pulp and in-solution use. VITROKELE adsorbent offers certain advan- tages over both carbon and ion exchange resin adsorbents. This paper describes testwork on Australian ores and commercial solu- tions obtained from operating Australian plants demonstrating the kinetic loading characteristics, elution methods and other operating parameters of VITROKELE adsorbent in the cyanide system. Brief reference is made to VITROKELE in the Gold III system.

Jan 1, 1988

This paper presents a rationale for selecting appropriate support elements which combine to form a support system to maintain stability in mines subjected to both strainburst and the shaking that occurs from fault slip. The overall approach was developed during the 'case for safety' study undertaken to allow the then Beaconsfield Gold mine (now Tasmania mine) to resume development and production after the 25 April 2006 ground-fall and fatality that received worldwide publicity. Issues of the sometimes competing requirements of support element performance during dynamic loading are discussed and the need for support flexibility is contrasted with the usual high support element stiffness required when these are used to reinforce rock masses. An example is presented to show the steps and technical details required to design each component of a support system to counter the de-stabilising effects of seismicity.

Nov 25, 2010

The automatic control of grinding mills for optimum performance is an area of control which can benefit from new control concepts and technology. Economic pressures dictate that the mining industry undertake changes in process design, control system strategy and operations organisation that call for innovative reappraisals of the control system performance necessary to enhance the functions of the process operator. As more dependence is placed on instrumentation the chances of abrupt, total loss of process control through an entire production complex becomes a major concern of the plant manager.

Jan 1, 1978

Some only types of bank finance are appropriate for mining development, with conventional fixed rate finance having significant limitations of flexibility. New, innovative and flexible instruments have recently been utilised within project financing packages. A strictly limited number of specialist project finance banks exists, with the necessary specialist personnel able to address project cost-competitiveness, cost and commodity forecasting, joint venture negotiations, and completion and sales undertakings. Different techniques of internal bank appraisal are applied, with the usual equity investment project valuation criteria being seldom useful for loan assessment purposes. Company attention paid to the preparation of a sensitively structured bankable presentation can prove most effective for securing development project finance. Substantial scope is possible for savings of time and money.

Jan 1, 1983

By Worotnicki G, Tillmann V. H

Past experience with fully bonded cable dowels placed as a means of reinforcement in highly stressed crop pillars at the New Broken Hill Consolidated Limited (NBHC) mine indicated such support was not fully effective. Typically overbreak of the crown occurred leaving long lengths of cables hanging from the back stripped of grout and rock with the potential load carrying capacity of the cables not having been fully utilised. This mode of behaviour had been observed in the cable dowelled crowns of three longhole open stopes (EROS) mined to the No. 12 level at NBHC. A system of support with improved mechanism of load transfer from rock to cable and capable of full utilisation of cable strength was proposed for the crown pillars of future Stopes.

Jan 1, 1983

By C L Humphrey

Biological monitoring programs for environmental protection require techniques that will provide both early detection of possible adverse effects, and assessment of the ecological significance of these effects. Monitoring techniques must include responses sensitive to the impact, that can be subjected to rigorous statistical analysis and for which statistical power is high. Such issues in baseline research of 'what and how to measure?' and 'for how long?' have been the focus of a program being developed to monitor and assess effects of mining operations on the effectively pristine, freshwater ecosystems of the Alligator Rivers Region (ARR) in tropical northern Australia. Application of the BACIP design, utilising a form of temporal replication, to univariate data (single species) and multivariate (community) data is described. For new ventures in Australia (such as mining), monitoring programs should be designed to establish with high probability that an impact on the ecosystem no greater than a prescribed amount has gone undetected - as opposed to simply allowing development to continue as long as 'proof' of impact is not available. Such a precautionary approach represents a shifting of the 'burden of proof' and would require with the BACIP design, a minimum number of baseline years in order to achieve some desired level of statistical power in a test for impact. Power analyses conducted on two to five years (depending upon the technique) of baseline data from streams of the ARR indicate that the BACIP design would not impose developmental constraints on mining and that a policy of reversal of the burden of proof would provide the cornerstone required for managing such development in an ecologically sustainable manner.

Jan 1, 1994

Pyrrhotite is pyrophoric when in a finely divided form. The problems of disposing of large quantities of finely divided pyrrhotite separated out by metallurgical processing from ore are formidable. In the case of an underground mine, a solution to the problem of disposal is to place the pyrrhotite in the stoped out areas and seal from any air supply. Further, the pyrrhotite could be diluted with tailings which would reduce the possibility of combust- ion. Several enquiries to various centres and authorities have shown that the products of the slow oxidation of pyrrhotite with moisture present can cement an inert matrix into a stable fill similar in physical prop- erties to fill stabilised with Portland cement. Stabilised fill can be used to advan tage with a suitable mining method to provide high recovery. The investigation demonstrated that air and 15% w/w water must be present for the fill to harden and that the sizing of the particles is a critical factor in drainage of a hydraul- ically placed fill and subsequent even harden- ing of the fill in a stope. With the materials used in the experiments in which the - 51 micron component of the tailings had been dis- carded, an optimum mix was found to contain 4:1 tailings/slag ratio and an overall pyrr hotite concentration of 8% (all proportion by weight). Approximately 34 days after drain- age to 15% moisture in natural air flow condit- ions, an unconfined compressive strength of 1.862 MPa was attained. A subsequent experi- ment was conducted with a sample of optimum mix in a pipe one metre long in forced air flow conditions. At a superficial velocity of 3.Om per hour the mix required 155 hours to harden to 1.862 MPa after drainage to 15% w/w moisture content. The pressure drop bet- ween the top and bottom of the mix in the pipe remained constant at 9 KPa/metre length. This result suggests that forced air flow conditions will increase the rate of hardening. No dangerous effluents were detected in the course of the experiments which could affect mine equipment or personnel.

Jan 1, 1973

By M Donatelli, E Grazio, A Heissenberger

The distribution of a contaminant in a bulk mass greatly influences the effectiveness of sampling procedures. Most currently used sampling guidelines for genetically modified organisms (GMO) testing have stringent distribution requirements. Specifically, all these protocols are based upon the assumption that GM material, if present, is randomly distributed. Yet, assuming randomness is risky because the applied sampling plan may not provide an accurate estimate of the content of the contaminant. Despite the general consensus that an evaluation of the possibility of non-random distribution of GM materials within lots is a pre-requisite for the definition of effective sampling protocols, no experimental data on the distribution of GMOs in kernel lots are available anywhere in the world. Additionally, to date there is no distribution-free statistical model to estimate sampling errors, thus making the theoretical definition of optimal sampling technique impossible when randomness cannot be assumed. Here we present preliminary results of the KeLDA project, which is the first study investigating the distribution of GM materials in large soybean lots imported within the European Union. The extensive variability of GM content, observable both within and among soybean lots, indicates that heterogeneity issues cannot be overlooked when defining sampling strategies for large lots of particulate material and that randomness cannot be assumed a priori. A new statistical model free from any distribution assumptions, developed in order to estimate the sampling error associated with different sampling protocols together with the risk of false-negative results, is also presented. The new model, which is applicable to any consignment of particulate material with respect to any kind of contamination, presents two novelties: first, freedom from any distribution assumption; second, the possibility of estimating the magnitude of the sampling error associated with different sampling protocols as a function of specific distributional properties.

Jan 1, 2005

Filter aids are currently used in many industries to increase filtrate clarity and filtration rates. In other industries filtration could be improved if accept- able filter aids could be obtained cheaply. The present paper describes a simple thermal process for making filter aids from coal, outlines the effects of coal properties and major operating variables, and discusses the properties of satisfactory products. Several possible variations in reactor design have been used experimentally, involving fluidized beds of carbon or inert material, reaction of the particles while entrained in air, and a combination of entrainment and fluidization. The limits imposed on product yields by the composition of the parent coal are considered in relation to a range of Australian coals and one New Zealand coal; and the effects of temperature, residence time, and reactant flow rates have been studied in relation to product yields and characteristics.

Jan 1, 1969

What is the best circuit to comminute primary crusher product to make beneficiation feed? Finding the best circuit to crush and grind minerals to beneficiation sizes is a complex problem that can lead to interminable discussion. Conclusions reached can be questioned. This will continue as long as the technology of comminution continues to expand, and is a mixture of many technical and economic factors in what is not a precise science. Laboratory and pilot plant procedures now exist that can help process engineers make sound decisions on which circuits are the best for crushing and grinding the specific ore being studied. It is the aim of this paper to discuss such procedures so a better under- standing of key decision parameters is avail- able, and to update comminution testing which has seen a. period of change in which new procedures have been introduced.

Jan 1, 1978

By M Hilden, G Forbes, Z Ye, M Yahyaei, F Reyes, V Jokovic

Soft sensors offer several practical advantages for the process control of comminution circuits by combining multiple conventional sensors and other data sources with real-time analysis using mechanistic, phenomenological or machine learning models. While there has been a growth in the use of machine learning techniques for developing soft sensors in minerals processing applications, this paper describes advantages and challenges of using soft sensor models developed on the basis of process knowledge. Recent experience with three new soft sensor technologies developed by the authors are discussed. The Mill Filling Inference Tool which has been implemented at several mine sites, compares SAG mill load cell and power draw measurements with outputs of a semi-mechanistic power model to estimate the mill ball and total filling in real time. The progressive wear of the mill liners is modelled, allowing the model to correct the load mass due to the mass loss automatically and to estimate the charge trajectory. This information enables the mill to be operated more confidently near its limits. A coarse-ore stockpile soft sensor as been recently developed using a 3D cellular automata-based model to track ore size throughout the pile, and estimating the live capacity and size at each stockpile feeder to the primary mills. Finally, a hydrocyclone soft sensor is being developed to monitor performance using available hydrocyclone models to estimate the size and flow balance around the cyclone in real time. The model-based soft-sensor approach aims to synthesise and analyse existing data and provide operators and engineers with process- and model-relevant information that can facilitate making better process decisions. Maintenance data has proven useful for model development as it allows soft sensors to automatically adjust and compensate for the effect of progressive wear, for example for mill liners, thus helping the models to maintain calibration throughout the equipment life.

Aug 24, 2022

By Shonhardt JA, Bagster DF

This paper firstly examines the pollu- tion potential of burning colliery wastes. A comparison of two means of estimating the pro- pensity for coal to combust spontaneously is next presented. The use of microwaves, as a new procedure, is discussed in detail, while a comparison of the results is made with a modi- fied adiabatic technique. A number of coals that are known to combust spontaneously was tested, as were some coals that are not consi- dered to have self heating potential.

Jan 1, 1987