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The Charters Towers goldfield in northeastern Queensland produced over 206 tonnes of gold from gold-quartz veins hosted by Mid-Palaeozoic granodiorite, tonalite, diorite and to a lesser extent amphibolite-grade meta-sedimentary schist and meta-igneous rock. Mineralisation occurs in grouped, moderately dipping shear zones with altered wallrock rafts and a complex network of quartz veins.Over 75 per cent of the production came from three main vein systems in the central goldfield: the Brilliant, Day Dawn and Towers Hill vein systems.The Brilliant vein system is hosted by undeformed tonalite and contains north-plunging oreshoots on a north-dipping main fissure and on shorter east-dripping hangingwall fissures. The Day Dawn vein system is localised along a north-dipping dyke at the contact of two deformed granitoids in a brittly reactivated mylonite, where horizontal oreshoot plunges may be related to the original megascopic undulations in that structure. The Towers Hill vein system is hosted in two granodiorite types and has multiple ore controls.Structural analysis indicates that the distribution of the oreshoots within the vein systems is variously controlled by the primary fabric and igneous contacts of the granitoid host rocks. Splaying, changes in dip, and fissure intersections are the main controls. The largest vein systems are both in reactivated shallow-dipping mylonite, or in fissures in younger undeformed granitoids. Each vein system lies in a separate structural domain, usually where older east-striking structures are preserved.

Jan 1, 1990

By Martin C. H, Met B

INDEX OF CONTENTS:1. Introduction, Explanatory; and Reasons for Coal Cleaning.2. Principles on which Coal Cleaning is based.3. Location of Broken Hill Proprietary Co. Ltd. Plant.4. Description of Processes Selected Barvoys Bath Process; Barvoys Medium Preparation and Treatment; Static Dry Cleaning Plant.5. Detailed Description of Plant.6. Typical Results of Cleaning Operations.INTRODUCTION, EXPLANATORY, AND REASONS FOR COALCLEANING:The Institute proceedings have not previously published any matter on coal cleaning and the reasons thereof; in consequence it has been deemed advisable to allot a part of this paper to explanatory matter, prior to entering into a detailed explanation and description of the Newcastle plant.At the outset it would be as well to consider briefly the kinds of materials from which coal has originated. All coals represent some stage in the decomposition and transformation of vegetable matter laid down in prehistoric times, the vegetable matter undergoing numerous geological changes, such as submergence, overlaying by sediment, with subsequent pressure and re-elevation; these processes may...

Jan 1, 1946

Laboratory experiments have been used tostudy a wide range of convective processes which are significant for the formation of rocks and the ores that form in them. Metal-rich solutions flowing through the sea floor produce 'black smoker' chimneys; both the size and structure of a solid chimney and the height to which the plume of effluent rises above it can be predicted using model experiments. Analogues of processes in solidifying magmas can also be studied using crystallizing aqueous solutions. The release of lighter or denser residual fluid as crystallization proceeds, and the resulting compositional convection, have a vital influence on the differentiation of initially homogeneous magma and on the evolution of stratified magma chambers. Mixing during the replenishment of magma chambers, and its dependence on the rate of filling and on the fluid properties, have also been studied on the laboratory scale. Experiments carried out in different geometries have been applied here to the formation of platinum and chromite ores and komatiite lavas. Larger-scale mantle convection, in particular the motion of subducting plates and plumes rising from the core-mantle boundary, also determine the tectonic settings in which ore bodies form. These phenomena too can be usefully investigated in laboratory experiments using very viscous fluids.

Jan 1, 1990

By Peck J. P, Kennedy D

Drill performance monitoring studies were recently completed at the Fording River mine, British Columbia. Microprocessor-based instrumen- tation and data analysis techniques were developed with the objective to improve short and long term mine planning. Data analysis permitted the identification of thicknesses and interfaces between soft/hard zones at depth based upon the recorded responses of the drill. Data clearly con- trast the soft coal seams and harder waste rock units based on variations in recorded drill rotary speed and torque, hydraulic downpressure, bail- ing air pressure and instantaneous rate of penetration. These parameters were monitored and recorded at 10 cm sampling intervals. Processed drill data was correlated with gamma logs, an existing means for locating coal seams and distinguishing between waste units. Current development of a pattern recognition module aims towards automated interpretation of drill data, identifying micro-and macro-geological and geomechanical rock mass characteristics. Delay between acquiring, processing and interpret- ing the drill data for practical use by mine personnel should be minimized. Integration of this technology with the mine's current main-frame based Mine Engineering Application System software will enable more accurate and timely annlication of the nrocessed drill data.

Jan 1, 1989

Geological hazards such as faulting, basement ridges, and zones of "thin" (

Jan 1, 1998

By Colwell JB, Cronan DS

Manganese nodules cover great areas of deep ocean floor far from land, and have long been considered a major potential resource of nickel, copper, cobalt and perhaps manganese. A decade ago there was a period of intense evaluation of nodule fields, especially those lying between the Clarion and Clipperton Fracture Zones in international waters southeast of Hawaii. There, nodules are abundant and of high grade (average of 2.4% Ni+Cu+Co). The evaluation activity has since declined, but a recent agreement on lease boundaries among all interested parties may lead to a resurgence of work. Indeed, French and Japanese groups have pushed ahead with field and economic assessments.The Southwest Pacific, where there are large nodule fields in the waters of the Cook Islands and Kiribati, has seen considerable assessment of resources in the last ten years, especially through a major field programme of the Japanese Metal Mining Agency. The best prospect appears to be in the South Penrhyn Basin, in Cook Islands waters, where nodules are very abundant but of only moderate grade (1% Ni+Cu+Co). Using a cut-off of 5 kg of wet nodules per m2, Cronan (1989) and Cronan et al. (1989) have estimated the total resource to be a huge 110 million tonnes of Ni+Cu+Co.

Jan 1, 1990

By Floyd JM, Bultitude-Paul J

The development of a process for the extraction of antimony from materials produced by Greenbushes Tin Limited has been carried out based on theoretical and laboratory studies. The materials treated have included concentrates of tantalite and cassiterite containing antimony at levels ranging from 0.3% to 2%. Roasting under controlled atmospheres is required to stabilise Sb203 rather than the low vapour pressure metal or higher oxide. Sulphidising additives such as pyrite, pyrrhotite or sulphur give enhanced antimony removal from tantalite and cassiterite at roasting temperatures of 900¦ to 1100¦C. Substantial elimination of antimony to levels of 0.1% or less was Achieved.

Jan 1, 1986

Developed and built in 1982 for simultaneous bathy-metric and reflectivity mapping of the deep ocean by the Hawaii Institute of Geophysics, SeaMARC II was a breakthrough in sea-floor mapping technology. The design was developed cooperatively by industry and academia, and the system has served as a prototype for a new generation of mapping tools for operation in both shallow and deep water.Research programs using the SeaMARC II system have focussed on basic research into the geophysical evo-lution of the Pacific, ranging from intra-atoll mapping to surveys of the deep-sea trenches. During the past few years most work has been concentrated on detailed investigations of the morphology of mid-ocean spread-ing centers, seamounts, and the subduction zones which surround the Pacific. The detail provided by the high resolution, 10-km wide side-scan sonar images of fault and fold structures, combined with the swath of bathy-metric information obtained simultaneously, allow previ-ously unattainable analysis of seafloor morphology and are leading to development of detailed models for ocean crust genesis and deformation.

Jan 1, 1990

By R F. G Phelps

The former Gwynfynydd gold mine is located within the heart of the Snowdonia National Park, North Wales, United Kingdom. The black shale-hosted quartz reefs have intermittently produced more than 50 000 ounces of gold since 1863. Its most recent period of operation by Welsh Gold PLC was between 1992 and 1999 when it extracted 10 000 tonnes annually from a total resource base of 180 000 tonnes. A historical mining grade of 15 grammes/tonne was recovered from the Chidlaw Reef on which all production was based. Erratically distributed gold pockets hosted in the footwall zone of a 3 - 6 m wide quartz reef characterise the mineralisation. The gold exhibits a high-nugget effect and as a consequence the accurate determination of tonnage and grade was difficult. Production was undertaken by overhand shrinkage stoping. Due to its location within a National Park certain environmental constraints were placed on the operators. The principal requirement of planning permission was that processing should take place above ground and not involve chemicals. As a result, an underground mill based on physical separation methods was constructed in response to these environmental constraints. Much of the mine discharge is related to the flow of rainwater through the workings from surface openings on the reefs. Discharge from the underground milling facility was enhanced in various metals, particularly zinc, though was reduced to legally acceptable levels using liming tanks prior to discharge into the River Mawddach. The company was required to monitor and treat all water discharged from the mine before it reached the river. The mine closed in 1999, since which time a tip re-processing has continued as part of an environmental remediation and gold supply program.

Jan 1, 2002

By Giuli M, Barnaba P, Sacerdote R, Tammaro F

Following a theoretical consideration of the effect of flooding, fluidisation and softening on blast furnace blowing limits, results are presented which show the effect of these parameters on operation. Industrial trials on Oscar Sinigaglia No. 4 BF are reported and results compared with those obtained theoretically and in the laboratory. It is shown that in these trials the furnace operated at levels of fluidisation very much (80-90%) below those theoretically calculated whereas in some cases (high proportion of sinter) actual hot metal output was near the calculated flooding limit. However, it was observed that as the sinter percentage decreases also actual productivity becomes lower than the one caused by flooding. This gap, which increases as other ferrous components (essentially acidic) replace the basic sinter was explained by the softening of the burden under bosh conditions. Softening indices measured on the individual materials yield support to this explanation. Coke rates data show that for approximately every one percent increase in the basic sinter in place of blended sized ore, a coke rate decrease of 1.1 kg/thm results. For acidic pellets this value is 0.6 kg/thm. Results of breakdown and reduction characteristics are also given and their indices compared with actual pt oduction. Measures to improve operations are proposed.

Jan 1, 1975

By Black LP, Law SR, Oversby BS, Mackenzie DE, Wyborn D

Three volcanic sequences of different ages occur close together in the Burdekin Falls area, southeast of Charters Towers in northeastern Queensland. The oldest is equated with the Cambro-Ordovician Mt Windsor Volcanics, and consists mostly of strongly deformed, regionally metamorphosed rhyolitic lava and minor feldspathic to quartzose sandstone. This unit is overlain by folded but unmetamorphosed Upper Devonian-Lower Carboniferous volcanics (DCv) of the lowermost Drummond Basin sequence. The primary volcanic facies of (DCv) principally comprises andesitic and rhyolitic lavas, and dacitic ignimbrites. Similar volcanics are widespread in the lowest formations of the Drummond Basin sequence elsewhere, and dominate that sequence east of the Anakie Inlier. The youngest volcanic sequence is Late Carboniferous and composed of lower, more deformed, compositionally diverse ignimbrites, lavas and conglomerates, overlain by generally less deformed rhyolitic ignimbrite sheets. The upper part is equated with the Bulgonunna Volcanics which extend 90km south to the Mt Coolon area. The Burdekin Falls area contains an ignimbrite stratigraphy different from that in the south. However, one of the most voluminous ignimbrites (Locharwood Rhyolite) in the southern stratigraphy is also present in the north, enabling the two to be correlated.Each of the three volcanic sequences reflects proximity to eruptive sources. Both the volcanics at the base of the Drummond Basin sequence and the Late Carboniferous volcanics are largely the products of subaerial eruptions. The former were erupted from several intermediate-composition volcanoes, and the latter from multiple-vent silicic calderas. All three sequences are considered to be prospective for precious and/or base metal mineralisation. Polymetallic massive sulphide deposits occur in the Mt Windsor Volcanics farther west, and many epithermal gold prospects and mines are hosted by the volcanics at the base of the Drummond Basin, especially east of the Anakie Inlier. The Late Carboniferous volcanic sequence is deeply eroded, and co-magmatic high-level plutons are widely exposed; this sequence may therefore be more prospective for deeper-than-epithermal mineral deposits.

Jan 1, 1990

Although forty-seven years have passed since the by-product coke oven made its successful commercial appearance, it is only during the past fifteen or twenty years that this system of coal carbonisation has advanced rapidly to its present position ofabsolute supremacy.Early designs of by-product ovens proved more or less faulty, and the coke produced was so inferior to coke made in beehive ovens that there was a natural hesitancy on the part of coke producers to invest large sums of money in installations of by-productovens of doubtful utility-more especially in view of the fact that beehive ovens could be erected cheaply and operated by non technical labour for the production of high-grade coke under the most variable conditions of trade.Surely and steadily designers brought forward by-product ovens of improved type, coupled with more efficient apparatus for the recovery of by-products, but still the industry lagged, due almost entirely to the insistence on the part of coke users that the qualityof ordinary beehive coke was vastly superior for metallurgical operations to the best coke produced from by-product ovens. So deep rooted was this prejudice that only the passage of time could eradicate it. That it has successfully done so is strikingly illustratedin the following statistics:

Jan 1, 1928

By S Williams, N McBride

The aim of these analyses was to utilise the latest available production information for the Wandoo operation to determine the optimal blasting parameters, costing information and predicted results (fragmentation, muckpile shape and vibration). Much of the data used as input was made available from the information gathered during the excavation of the test pits during 1995. As with any æplanning stageÆ analyses, many assumptions were required to fill gaps in the available data. The calibration of computer blasting models was conducted using data from the last of the test pit blasts (this blast was carried out in material that closely resembled rock expected to constitute the bulk of the base case design pit). This calibration was refined using observation and experience based judgements to extend the accuracy of the predictions as far as possible. All the simulations were performed assuming that the blastholes will be wet (as instructed by BGM). This has consequently determined that the appropriate explosive for the simulations and the actual blasting will be a pumped emulsion/ANFO blend. The following blast design parameters were derived by determining a likely range of powder factor (from other similar scale gold mines) with a median value of 0.62 kg/m 3 being the powder factor arrived at through the field optimisation process conducted during the test pit excavation. The total swell/displacement percentage (volume after blast/volume before blast) largely determines the diggability of a well fragmented muckpile. Consequently where fragmentation is good any reduction of total swell will probably reduce diggabilty. Any reduction of diggability can and should be traded off against increased gold recovery. In most gold mines, diggabilty will be substantially compromised at the balance which produces the most profit. When these considerations are combined with the cost to drill and blast material, processing costs and the achievement of æacceptableÆ diggibility, the analysis becomes extremely complex and qualitative. Many trends are evident including:the relationship between powder factor (for each blast design) and maximum forward displacement (throw), see Figure 1; and the relationship between powder factor (for each blast design) and drill and blast cost per BCM, see Figure 2. The following blast designs are matched to each of three ore-tonnage alternatives (as supplied by BGM) (Table 1). They are all based on powder factor of 0.62 kg/BCM and are considered optimum from a mining æpoint of viewÆ. The costing of each design includes drilling, explosives and labour cost to load, stem and tie-in holes. Using the available rock data and relying heavily on the wall exposures in the test pit(s), it is the opinion of the author that between 20 per cent to 40 per cent of the final walls excavated in the Wandoo pit would be likely to have the angle between the dominant foliation and the wall plane that is well suited to presplitting and be cost-effectively served by presplit technique. The drilling cost for 125 mm blasthole is about $11.40 per drilled metre and the cost of 40 mm presplit explosive is about $140 per 25 kg (17 metre) case. This implies that the cost to drill and blast presplit on the above parameters would be about $10.90 per square metre of presplit face. The remaining wall area would be most cost-effectively delineated using modified production blasting techniques. This requires the use of modified parameters such as smaller hole diameters, smaller spacing/ burden, higher powder factor, free face firing, less rows per blast and longer delays. These altered blast parameters would usually be applied uniformly across the entire blast fired adjacent to the wall and this ætrimÆ blast would relieve burden away from the wall, into the pit. In simplest terms, this method relies upon maximised burden relief to minimise blast energy applied to the wall. It is only applicable where the material to be blasted is waste since the throw achieved is inconsistent with ore dilution control. The largest charge weight per hole for these analyses is 360 kg and the nearest domestic structure to the proposed Wandoo pit is about 6100 metres distant. From these parameters and assuming a worst case example of rock controlled site factor, the predicted ground vibration is 0.5 mm/sec that is about five per cent of the lower limit set down in AS 2187 part two (1993). This suggests that for the current location of neighbours, ground vibration will not be an issue for the Wandoo operation.

Jan 1, 1999

By L. Gilbert

Recent changes to environmental legislation and trends in the environmental regulation of mining in the Northern Territory are being driven by (among other factors) Federal Government policies and international agreements on the environment. These trends are discussed and the expected application of the NT Water Quality Management Strategy (based on the National Water Quality Objectives) over the next few years is examined with respect to mine environmental management practices. Some of the potential conflicts and changes in approach which may develop are identified and examples discussed. Proactive means of integrating trends in environmental legislation with mine planning and waste management are discussed.

Jan 1, 1994

By J A Evans

A well-maintained and low cost mining operation today requires the use of condition monitoring techniques. At ERA - Ranger Mine oil analysis, vibration monitoring, infra-red themtography, and performance analysis have been successfully applied over the last four years to lower operating and maintenance costs. All condition monitoring is scheduled through a comprehensive in-house developed maintenance management system known as the Engineering Information System (EIS). (EIS) is used extensively at Ranger to ensure consistent frequency and recording .of all condition monitoring data. This paper provides an insight into the benefits of condition monitoring and explores the future direction for condition monitoring techniques at Ranger.

Jan 1, 1994

By W Liu, S Gao, D Wei, B Cui, Z Guan, Y Shen

Beneficiation of low-grade fine-grained hematite ores becomes increasingly important due to rapid depletion of high quality iron ore resources. However, fine particles, especially ultra-fine particles, make efficient beneficiation of these ores more difficult. Therefore, methods to reduce the influence of fine particles must be considered to achieve better beneficiation performance. Analysis and systematical beneficiation tests were carried out on an ultra-fine-grained hematite ore slime from washing a fine grained hematite ore. Ore particles were found to be presented in loose soil. While some of the ore particles were agglomerated, they were very fine and contained up to 76.5 per cent -0.023 mm material. In this paper, using a single magnetic separation flow sheet with sodium silicate (SS) as a dispersing agent, a concentrate containing 65.05 per cent Fe was obtained at an iron recovery of 68.58 per cent from the hematite ore slime of 56.65 per cent Fe. The single magnetic separation flow sheet was simple and reliable, the agent SS was effective in dispersing ultra-fine particles. The results are believed to be applicable to similar hematite ores.CITATION:Wei, D, Guan, Z, Gao, S, Liu, W, Shen, Y and Cui, B, 2013. Beneficiation study of an ultra-fine-grained hematite ore slime, in Proceedings Iron Ore 2013 , pp 495-500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By D C. Verdon-Kidd, G R. Hancock, M J. Saynor, J B. C Lowry, T J. Coulthard

Designing post-mining landscapes requires quantifying the short and long-term risks. In recent years, computer based landscape evolution models (LEMs) have been used to provide insight into both erosion rates and processes (i.e. sheetwash, rill, gully erosion). An important requirement of these models is high quality model input parameter data, which includes both the surface material (i.e. soil and waste rock) and climate information. However, in many cases such data is limited and in the case of climate information, the data is often short and incomplete. Here we develop climate scenarios and examine different surface material properties using a case study at the ERA Ranger mine located in the Northern Territory, Australia Firstly we develop scenarios that represent the range of future climates that may be experienced at the site. Secondly we develop a series of plausible particle size distributions based on a large sampling exercise of the waste rock material. We then test the sensitivity of different rainfall sequences and surface materials on sediment output using a well-tested landscape evolution and sediment transport model (Hancock et al., 2017). CITATION:Hancock, G R, Verdon-Kidd, D C, Coulthard, T J, Lowry, J B C and Saynor, M J, 2018. Quantifying the effect of climate and surface materials on post-mining landscape erosion – a risk approach using landscape evolution models, in Proceedings Life-of-Mine 2018, pp 122–124 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By de Vries D, Wilson EG, Henderson GAM, Carter EK

Canberra is a planned city in which the natural environment, rather than existing development and land tenure, has until recent times at least, imposed the major constraints to development. Even redevelopment poses fewer problems than for most cities. Geological conditions have, therefore, played a significant role in determining its shape and layout. The Canberra experience has relevance for major new mining and engineering projects. The role of engineering geologists and geophysicists in Canberra's development is described, and the problems arising from the geological environment are illustrated by several case histories. Four aspects are addressed: pre-development urban geology; major engineering projects; resources evaluation, including groundwater; and post-development problem-solving. The Australian Capital Territory lies within the Palaeozoic Lachlan Fold Belt. Within the ACT the belt is composed of folded and faulted metasiltstones, metasandstones and acid volcanics, intruded by a major granitic pluton. Some limestone lenses occur. The region has been part of a land mass since Late Devonian times and landscape evolution has been very complex. Geological features of special geotechnical significance include deep but variable weathering, with slight to moderate weathering along faults to at least 70 metres depth in places, and consequential foundation problems; close jointing; weathered limestone lenses with solution cavities containing clay and water; confined aquifers containing artesian water in scree deposits flanking hills; the presence of pyrite; and poor quality and low volumes of groundwater.

Jan 1, 1986

By Greenhalgh L. P H

The opportunities offered by an increasingly volatile world invite the international consultant or engineering services contractor to broaden attitudes, diversify interests, expand capabilities, retain and develop specialist skills and base judgements upon sound principles and solid experience. The wide-ranging scope of this review reflects such a change but the topics of discussion are not intended to be exhaustive or to detract from many other current developments.The subject of environmental protection, effluent control and pollution prevention is a primary consideration in the application of many mineral processing technologies but is not covered here. There is an array of developments relating to noxious gas emissions and toxic wastes and the paramount importance of this matter justifies comprehensive conferences dedicated solely to the application of suitable measures. This review concentrates therefore on the main stream processing techniques for the primary recovery of values.

Jan 1, 1993

By Miskelly N

Construction of the Ranger uranium project located 230 kiss east of Darwin in the Northern Territory commenced in January 1979. Energy Resources of Australia Ltd (ERA) was incorporated in February 1980 to acquire all the rights in the project. The total cost to ERA of these rights was $407 million, made up of $125 million in cash to the Federal Govern- ment and the issue of 125 million $1.00 shares at par, plus a payment of $16 million in cash to each of Peko-Wallsend Ltd (Peko) and EZ Industries Ltd (EZ).

Jan 1, 1983