Search Documents

By Peters S. G, Beams S. D

CONCEPTS AND REGIONAL GEOLOGY The Charters Towers region holds many keys to the metallogeny associated with the complex geological development of eastern Australia during the Palaeozoic. Tectonic, magmatic and volcano-sedimentary depositional episodes can be identified and related to the chronological development of batholithic host rocks (Clarke & Paine, 1970; Henderson, 1986; Murray, 1986). Pre-batholithic basement rocks in the north (Charters Towers Metamorphics) consist of a package of amphibolite grade schists interlayered with and intruded by gabbros and diorites (Peters, 1987). To the south (Seventy Mile Range Group) greenschist facies Cambro-Ordovician rocks overly some of the basement. The lower age of this basement is not constrained, parts of it could be as old as Pre-Cambrian. Mid-Ordovician (approx. 470 my) to Lower Devonian (approx. 400 my) age I-Type granitoid plutons of the composite Ravenswood batholith intrude the pre-batholith basement and the Seventy Mile Range Group. Igneous activity was initiated again in the Carboniferous with the extrusion of rhyolitic lavas and pyroclastics associated with porphyry and high-level intrusive complexes (Wyatt et al., 1971). The Ravenswood block is bounded by Devonian and Tertiary sedimentary sequences of mainly continental provenence.

Jan 1, 1989

By Trueman R

If continuous mining systems are to be successfully applied in metalliferous mines then reliable models will be needed to predict rock cutting machine advance and tool wear rates for effective machine selection before mining commences. Many of the predictive models developed to assess cuttability in situ are over-simplistic. As a result they tend to be both site and/or machine specific. Nevertheless very detailed models have been developed for full face machines which are capable of accurate cuttability predictions in a variety of rock mass conditions and for a variety of machine and tool configurations. However, models to predict productivity and tool consumption for partial face machines are not as well advanced. There is a need to develop reliable models for partial face machines such as Roadheaders, the Robbins Mobile Miner and the HDRK-Wirth CMM, as these types of machine are likely to predominate in a mining environment. The paper outlines the current state-of-the-art for predicting cutting machine performance and the work being carried out within the Centre for Mining Technology and Equipment (CMTE), in collaboration with the Australian mining industry, to advance our capability in this area.

Jan 1, 1995

An effective production control system should maximise recovery of economic material from the resource. To do this, internal waste must be accurately delineated and efficiently removed. Achieving this is most difficult in low grade blocks just above and just below the cut off grade, where ore:waste separation follows assay or statistical, rather than geological boundaries. Difficulties arise from sampling errors, configuration of the economic mineralisation, and local variations in geology. Mine bench parameters and mining equipment size apply further constraints to the actual field separation of the ore from the waste. At BCL, management of the resource starts with an effective orebody model for planning, scheduling and ore:waste prediction. Ore production from each mining location is reconciled with concentrator tonnage and grade, and the reconciled grades are compared with the planning orebody model to highlight any Differences.

Jan 1, 1986

By Miles M. J, Sandy D. A

It has long been known that drilling and blasting operations have a direct influence over productivity and costs of subsequent operations. If mine management is to effectively optimise blasting operations, good information is required on the operating costs of each of the affected operations, together with knowledge of how they are influenced by blasting. In practice it is not possible to do enough repeats of a full scale production blasting experiment to make a statistically significant analysis of the results. By monitoring each blast and subsequent operations in as much detail as possible, enough data will be available to effectively measure the effect of blasting on costs. This gives management an insight into the blast performance and is the first step towards optimisation. An Integrated Blast-related Cost Reporting System has been developed at the Rossing Mine Open Pit, which calculates the total mining cost for each blast. In assessing the total mining cost for each blast, use was made of an.integrated planning and management information system to collect relevant production variables, current operating costs and survey data. An automatic image analysis system was employed to measure the fragmentation of the blasted material in the back of haul trucks. A shovel monitoring system is also under development for use in assessing the muckpile diggability and, in conjunction with an appraisal of shovel component reliability, to estimate the maintenance cost under various digging conditions.

Jan 1, 1990

By Dutton D

In the British coal mining industry, during the last decade, a great deal of environmental monitoring experience was acquired, particularly in the Doncaster Area of the Yorkshire coal- field, which had a long history of spontaneous combustion and gas emission problems. This paper summarises the experience obtained and shows how the introduction and operation of these systems has resulted in improved techniqu- es for fire detection and control. Some of these systems are described in detail with emphasis placed on the uses to which output data are put, and their impact upon management at colliery level. Reference is also made to the problems encountered in the development of such systems and how they were solved. The paper also makes reference to the recent Research and Development work of the NCB's Scientific Department and Mining Res- earch Development Establishment (MRDE), which was directed to the design and application of a range of underground sensors, and so ensured continuing progress in this field. The paper refers briefly to a new comprehensive monitoring unit and an integrated fire detection and data transmitting system which are currently being assessed in the Yorkshire coalfield.

Jan 1, 1983

The introduction of new technology into thegold-mining industry has been encouraged in recent years by increases in the price of gold andthe necessity for costs to be contained.At most new gold mines, run-of-mine millingis preferred over crushing and multistage milling, and this change at the head of the circuit leaves no place for the manual sorting of ore and for gravity concentration in the mill circuit.Flotation continues to hold its place in goldrecovery. However, a decline in the demand forsulphuric acid may limit the amount of pyrite thatcan be roasted before cyanidation.

Jan 1, 1984

By Thompson AG, Cadby GW

The New Austrian Tunnelling Method (NATM) is a proven concept for the safe and economic construction of underground facilities. This is especially true for tunnelling activity where changing ground conditions are often encountered. However, the principles central to the NATM have gained only limited use within Australia, presumably due to the measurement process inter- fering with tunnel driving and the cost associated with instrumentation and interpre- tation expertise. The design and operating principles of two basic instruments are explained together with laboratory simulated test results and suggest- ions for use in an integrated NATM style approach to underground excavation and construc- tion. The two instruments monitor load in rock reinforcement and deformation in rock or primary and secondary linings. The instruments may be fitted with a miniature display module which outputs the measured parameter in engineering units directly. The design of the sensing components allows the instruments to be installed in various configurations suitable for routine performance monitoring, quality control, support element testing or detailed investigations. The display module which reduces the need for instrumenta- tion expertise should suit contractors and allow performance data to be obtained which quickly may be used to modify support procedures to suit ground conditions. When complemented by convergence measurements the devices enable most facets of the NATM to be implemented.

Jan 1, 1987

By R Dunne, S Hart, G Levay

While water represents a major proportion of the mineral pulp processed in flotation circuits, relatively little research effort has been committed to understanding and controlling the influence of water quality on this process. Historically, this probably stems from the perception of water as an inert transport medium. However, the changing attitude towards water as a valuable resource, has given impetus to increasing requirements to use relatively impure make-up water supplies such as treated effluents and a high proportion of internally recycled water. In turn, this has resulted in the need for a more detailed focus on process water quality and its control to minimise adverse effects on sulfide flotation. Along these lines, prior to commissioning of a new concentrator at their Cadia Hill Gold Mine, Newcrest Mining was proactive in examining potential water sources and the influence of water quality on flotation of their copper/gold bearing ore. An extensive water quality survey of all major potential water supplies to the concentrator was undertaken. The flotation performance of the Cadia ore in each of these waters was investigated on a laboratory scale. The results of these studies identified that water quality could indeed have a significant influence on the flotation process. Since operations at the Cadia Hill concentrator began, water quality surveys of both make-up water sources and recycled flotation circuit waters have been carried out on a regular basis. By doing this, a database of water quality has been established which can be compared with plant performance. In parallel with the water quality surveys, a series of laboratory flotation tests have been conducted using a standard ore and waters from various streams to monitor changes in flotation performance as a function of water quality. These tests have indicated that certain water types may have a significant influence on plant performance. More research is required to better understand the impact of water quality on sulfide flotation. This understanding will help operators to minimise adverse effects, while maintaining the best utilisation of available water resources.

Jan 1, 2003

By G de Jong, W Sunyoto, M Cloos

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Ertsberg mining district is a 100 km2 area in the highlands of Papua, Indonesia. The district hosts mineralised and barren, outcropping and hidden porphyry and equigranular intrusions. There are at least six major (100+ m wide) porphyry intrusions identified from surface and underground mapping and drill cores. These are the Grasberg Igneous Complex (GIC), Karume porphyry, Lembah Tembaga porphyry, Ertsberg Stockwork Zone porphyry, Kay intrusion and the Wanagon intrusion. Recent deep drilling adjacent to the GIC identified a new hidden porphyry at depth, the Gajah Tidur (Sleeping Elephant), which extends south-west beneath the Kucing Liar skarn. Other named small porphyry dykes and plugs in the district include the West Grasberg, North Grasberg, Idenberg, South East and Zaagkam intrusions. The largest equigranular intrusion is the multiphase Ertsberg diorite.Igneous activities occurred in a relatively short span (<1 million years) from about 3.4 Ma to 2.7 Ma ago, based on U-Pb zircon dating. The various intrusions in the district related to ore mineralisation are high K and appear to have been derived from the same parental chamber, based on similar whole rock rare earth element patterns. Radiogenic Nd- and Sr-isotopic variations indicate that there were multiple recharge events into the parental chamber.The larger intrusions and all economic mineralisation occur in a 4 km wide zone that parallels the N60W-trending axis of the Yellow Valley Syncline (YVS), one of the large folds generated during collisional tectonism. Intrusion pathways at ~3 Ma were localised into dilatational areas in a late and/or post-collisional NW-trending, left-lateral strike-slip zone with Riedel shear offsets between the major fault zones. An early phase of lower K magmatism produced small intrusions in the south-west limb of the YVS.CITATION:de Jong, G, Sunyoto, W and Cloos, M, 2015. Composition, lithochemistry and radiogenic isotopes of porphyritic and equigranular intrusions in the Ertsberg mining district, Papua, Indonesia, in Proceedings PACRIM 2015 Congress, pp 347–356 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Y Gu

The Mineral Liberation Analyser (MLA) employs the technologies of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The use of backscattered electron images to define phase boundaries produces very high resolution image analysis and subsequently detailed and accurate particle images and data output. The mineralogy, elemental deportment, grain size, liberation characteristics and mineral associations of a large number of samples can be described. The MLA uses a comprehensive set of analysis methods to meet a wide range of applications. The data from ore characteristion projects completed during feasibility studies are important aids for effective plant design. The MLA can be used to establish variation in the mineralogy of an orebody, identify and quantify the deportment of deleterious elements, and provide valuable information to support comminution and flotation test work. In established plants the MLA data is an important component of plant survey work and monthly composite samples. Changes in feed characteristics and/or operating conditions can be monitored and solutions to any deterioration in recovery and grade performance found. The MLA has extensive applications in the minerals industry. Rare and precious metal samples can be accurately measured using high-resolution grey-scale images. Several new measurement techniques have been developed to perform rapid searches of a large number of samples to provide efficient and accurate analyses of fine-grain, low concentrate material. Quantifying the mineral variability in mineral sands operations is essential to maximising grades and recovery. The MLA produces particle-based data on density, mineralogy, size and shape and has developed measurement techniques to provide the elemental quantification required for the characterisation of these deposits. Nickel sulfide ores can be analysed to provide modal mineralogy, elemental deportment and liberation and locking data. The low-grade and variable nickel mineralogy of these deposits makes the use of quantitative mineralogy an essential component of maximising returns. Coarse particle measurements preserve the in situ textures of ores and support flotation and breakage test work for feasibility studies. The deportment of penalty and bonus elements can be quantified and the association and grain-size data can be used to identify potential separation issues.

Jan 1, 2006

By Eyers G. C

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

A conventional Bucket Wheel Excavator (BWE) system with conveyor transport, mobile tripper and spreader was commissioned at the Goonyella Mine in 1982. The system was introduced to prestrip ahead of dragline excavations and was specified to remove 7.5 million cubic metres per annum in ground somewhat harder than that inwhich bucket wheel excavators are normally operated.This machine has, since 1982, moved more than 77 millionbank cubic metres of material and has been relocated twice. Extensive trials have been undertaken including digging blasted rock.

Jan 1, 1992

By Szymanski J

In the first part of this paper, the principal sources of dilution during underground evaluation and mining are discussed, then definitions of ore dilution currently in use are analysed. These definitions vary depending on the authors. Ten different analytical expressions of dilution percentage currently exist. It is demonstrated, with the help of a numerical example for a given mining condition, that dilution percentage results vary considerably and that they depend on the definition used. This situation makes it difficult to compare different results regarding the dilution problem, often because some of the terms used are contradictory. A new ore dilution evaluation methodology is proposed, replacing the ten different analytical expressions by only two: the planned dilution factor related to the stoping selectivity, done at the mine planning level, and the additional dilution factor related to the efficiency of the dilution control measures during stoping operations. The conclusion shows that the use of this methodology would be a definitive asset in planning, in stoping operations follow-up, and in future costs comparison studies between mining operations.

Jan 1, 1995

By Bloom M. S

Epithermal vein and breccia hosted Au mineralisation at the Kerimenge prospect, in the Wau district, Papua New Guinea, occurs within a block of multiply fractured dacite porphyry of Pliocene age, and is localised on intersecting regional fault structures, marginal to the eroded vent of a Late Pliocene-Pleistocene maar volcano (diatreme).Au mineralisation is primarily controlled by the steeply dipping Kerimenge Fault zone, which hosts a basal zone of silicified breccias,transitional laterally and vertically to networks of fracture controlled veins.Early quartz+pyrite veins, deposited from CO2 rich, NaCl saturated, boiling fluids pre-date the main phase of Au mineralisation. Four stages of Au bearing vein mineralisation have beenrecognised. Quartz+sulphide veins (stage 1) and partially coeval quartz+sulphide+carbonate+ adularia veins (stage 2) occur marginal to silicified breccias, and are associated with quartz+sericite+pyrite wallrock alteration. Similar depositional conditions prevailed for stage 1 and stage 2 mineralisation. Mineralising fluids underwent two stage boiling at temperatures of 145 to 2300 C. Boiling resulted in the loss of approximately 3 wt.% CO to the vapour phase. 2 Fluid salinity was probably I wt.% NaCl or less.

Jan 1, 1990

By Marquez W

Trace fossils have been found in Bolivian Silurian sediments in "La Iumhre" area close to La Paz-Bolivia.Tracks, are good indicators of depth and environment. A detailed study of the ichnogenus is made.The depth and environmental deposits are analyzed to determine the facies. It was shown that the trace fossils of Silurian sediments in La Paz belong to the Zoophvcos and Nereites facies.

Jan 1, 1990

THIS paper deals with the handling of the various materials used in the 100-ton zinc plant at Risdon, and, in view of the magnitude of the works, the configuration of the ground covered by these works, the variety of the rnaterials used, and the large quantities, a very attractive and interesting subject is opened.The works are situated on the right bank of the River Derwent, about four miles above Hobart, the capital city of Tasmania. The Risdon works cover a space of 149 acres, the area being :3800 yards long by 2800 yards wide, and the elevations vary from 6 ft. above high-water mark at the wharf and foreshore to 163 ft. above high-water mark at the power station, these being the limiting points as regards elevation which are considered in this paper. Throughout the paper elevations are given in feet above high-water mark. Fig. 1 shows a general view of the works taken from the opposite bank of the River Derwent. The wharf is clearly shown, with SS Kekerangu loading residue; behind the wharf is seen the inclined conveyor leading to the cakine bin; further up the hill is the leaching division. No. 1 haulage runs to the left of this up to a point on the left of the power station, the large reinforced concrete building at the top of the hill. Below this is the cell room, the largest building on the plant. The roasting division, not very clearly seen, lies at the foot of the main stack, and the casting division lies to the left of this, between the leaching division and the cell room. A large wharf has been construl'ted alongside the works. This wharf is 880 ft. long and 60 ft. wide. It is capable of berthing large overseas steamers, as at low tide there is a depth of :30 ft. of water. The rise and fall of the tide at the wharf is 4 ft. 6in., and the river is navigable at all states of the tide. Just above the company's wharf...

Jan 1, 1923

The paper describes the geotechnical as- pects of design and construction of two 12 m diameter concrete lined tunnels from the start of design to completion of construction. Prob- lems occurred due to delay in supply of essen- tial rock support materials from overseas and alternative methods using locally available materials were developed. Several major rock- falls and rock movements occurred and remedial measures are outlined.

Jan 1, 1981

Coal Mining Land Use on the southern coalfields often preceded other land uses. Over the past century overlying land use has altered significantly, particularly with water supply storage development, road system building, railways, pipelines, electricity reticulation schemes and general urban develop- ment. National Parks were declared over coal bearing lands. Little regard was paid to the coal under the land surface by land developers, Government instrumentalities, central planners and the Metropolitan Water, Sewerage and Drainage Board and others, and little value was placed on this valuable energy source. These bodies derived no benefit from the under- lying mineral. In these circumstances, mine operators and such surface land users were put into adversary roles. Mass sterilisation of coal resources resulted. The loss of reserves continues, although the problem has become better under- stood. An Energy Impact Statement (EIS) submission by all surface land developers has been proposed as a means to justify the impact of the development on the coal reserves Beneath.

Jan 1, 1979

By Wooller R

The 3-D regular block model used for long term mine planning at Hamersley Iron did not fulfil the requirements for short term mine planning in terms of accurate representation of geological structures, contacts and boundaries in the orebodies. A computer model, based on zone plans, is being created as a single orebody model for all phases of mine planning. The zone plan is the primary interface between the geologists and mining engineers. It is essentially a bench plan at mid-bench height showing geological structure, material type boundaries, the grade and physical characteristics of ore blocks. The method allows for the dilution of ore zones by waste material. The stratiform nature of the orebodies allows zones of varying grade to be readily delineated on the plans. The Zone Plan Model (ZPM) is the interface between geological and mine planning computer systems. It is the basis of all mine planning with applications including long and short term mine plans, reconciliations, general ore reserve estimations, pit design and general model enquiries. The system was designed to be user driven. The user has complete control at all times as all computer generated data are fed back to the user who may then elect to override the computer. Various controls were built into the system to ensure model validity and integrity. The system has proved to be invaluable as a tool for users with little or no computing experience.

Jan 1, 1986

By M McGeough

Following the success of calcrete sampling at Challenger, calcrete sampling has been widely adopted as the primary exploration technique for gold exploration, in the Gawler Craton. Calcrete is uniformly distributed over large areas and produces discrete gold anomalies. This allows drilling to focus on specific gold anomalous targets. However, despite widespread use of calcrete sampling, very little is known of the origin of calcrete in the Gawler Craton, and the link between calcrete gold anomalies and primary mineralisation. In an attempt to understand this association Lisa Gibbons recently completed an honours project at the Old Well Prospect approximately 45 km SSE of Tarcoola. Her work is part of a collaboration between CRCLEME, MESA and MIM Exploration. At Old Well, a calcrete anomaly (>10 ppb Au)covers an area approximately 7 km x 2 km with a peak value of 97 ppb Au. The study looked at the regolith as a whole, processes of its formation and nature of mineralisation within it. She was able to combine previous calcrete and drilling results with her own observations. The results from this study highlighted problems in relating surface calcrete anomalies to in situ gold mineralisation.

Jan 1, 1998