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By Whiting AN

Major changes in the world in recent years are changing the criteria for selection of future developments. Oil prices soared during the 1970's while commodity prices including metals and minerals fell. Many new independent nations, have been created and now control the resources in areas which were once part of great colonial Empires.

Jan 1, 1983

By Freeman NV

The concept of an in stream analysis probe was developed at The Zinc Corporation (now Z.C. Mines) in the late 1960's and commercialised quite rapidly, by Phillips and then AMDEL, as an alternative to the established centralised systems (Courier, etc.). The developments which have taken place since that time are reviewed and current procedures and performance are described. An audit of the system, recently undertaken by AMDEL, has highlighted areas where improvements can be made. In 1988 the ISA system will become an integral part of a substantially upgraded process control system.

Jan 1, 1988

By Tooley S. M

An experimental investigation of the hydraulic cuttability of coal from the Theiss Dampier Mitsui mine near Moura, Central Queen land illustrated the ability of established cutting equations to describe the behaviour of the coal during cutting. The experimental equipment developed for the work proved reliable. The results of the experimental programme are consistent with accumulated experience from overseas.

Jan 1, 1985

City Resources Limited selected Vanuatu as a target area for epithermal gold mineralization because of its relatively unexplored character and its location on the southwest Pacific rim. During 1985 a systematic program of reconnaissance prospecting was completed on six islands within the Vanuatu group, using a helicopter and a specially designed exploration support vessel with on-board assay laboratory. Within a period of 4 months, reconnaissance prospecting of all six islands was completed, two previously unknown epithermal gold provinces had been discovered, and six major prospects warranting detailed exploration had been identified. Factors which contributed to the success of the program include (i) a flexible management approach, (ii) the mobility and access provided by the support vessel/helicopter combination, (iii) rapid assay turn-around, and (iv) adherence to basic prospecting techniques. The relative merits of various sampling media are discussed.

Jan 1, 1987

By A D. Bugarski, G H. Schnakenberg Jr

An investigation was carried out at a US underground mine to characterise diesel aerosols and to asses the effects of various control technologies on the concentrations and properties of particulate matter and gases emitted by heavy-duty diesel-powered equipment. This study was dedicated to evaluating the impact on mine air quality of contemporary diesel particulate filter (DPF) systems installed on mining equipment. Additional efforts were made to assess the effect of blended biodiesel fuels, yellow grease and soy, ultra-low sulfur fuel, a fuel emulsion and of selected diesel oxidation catalysts on air quality and emissions. The carbon analysis performed on the collected samples showed that the tested DPF systems reduced the mass concentrations of elemental carbon in mine air by between 70 per cent and 92 per cent. In addition, TEOM measurements, collected during these tests, showed that the total diesel particulate matter concentration in the mine air was reduced by greater than 65 per cent when DPF systems were used. The tested biodiesel blends were found to reduce elemental carbon concentrations in the mine air by between 49 per cent and 33 per cent, for the B20 (20 per cent biodiesel/80 per cent #2 diesel) of soy and yellow grease respectively and between 66 per cent and 56 per cent for the B50 (50 per cent biodiesel/50 per cent #2 diesel) of soy and yellow grease, respectively. The water-in-diesel fuel emulsion was shown to reduce elemental carbon concentrations by as much as 85 per cent. NO2 measurements showed an increase in the maximum concentrations of NO2 when catalysed DPF systems were used instead of mufflers.

Jan 1, 2005

By C T. Dunbar, P A. Walker, G E. LeJuge

A programme of blast improvement was initiated at the Mt Whaleback iron ore mine by BHPIO management in early-1998. One component of that work was the need to improve wall control blasting practices to better achieve the designed pit slope elements. This paper describes the geological conditions in which pit walls are developed, the mine operating equipment, the blast design concepts applied to minimise blast damage, the techniques applied in an assessment of the blast performance and the operational procedures developed to ensure that the blast concepts are effectively implemented in the production environment. Substantial changes have been implemented in both technical and operational aspects of the mining operation in order to achieve the improvements in pit wall condition, in particular recognising the need for a more flexible approach to limits blasting in response to highly variable and complex geology. The benefits to the mine are not only an improved wall condition, but increased confidence on the part of mine management that mine plans may be implemented on design and on schedule.

Jan 1, 2001

By Hempenstall J, English W

Mine management has a responsibility under the various acts of state parliaments for the adequate ventilation of existing workings. It also has a need to plan adequately for the ventilation of proposed workings. Future workings alternatives have become progressively more complex and ventilation planning of the various possibilities must be undertaken within an atmosphere of rapidly changing market circumstances, etc. Any non-optimal solution will prove more expensive than necessary on both capital and cost bases. Clearly these increasing and alternative ventilation demands of coal mines in Australia have multiplied the work load of ventilation engineers. Management in general has for some time been aware of the advantages of using computers for commercial applications such as payroll and stores inventory. However, while the hand held calculator has replaced the traditional log tables and slide rules for smaller engineering calculations, the larger digital computer has not made the same

Jan 1, 1983

Madison Enterprises Corp. and Matu Mining are currently ex- ploring the Mt. Kare property in Papua New Guinea. The Mt. Kare gold prospect has had a short but very active history, since the first discovery of gold in the area in 1986 the property has sccn: a 3 year gold rush during which 10,000 alluvial miners re

Jan 1, 1997

By Aziz N. I

Examination of the geology and support performance at two site leads to development of an under tanding of the influence of caving on powered support rating. The two site represent the current extremes in support rating, i.e. 6/260 tonne supports operating in the Hirst seam at Solsgirth Colliery, Scotland, and 4/900 tonne supports operating in the Bulli seam, West Cliff Colliery, Australia.A conceptual model considers the coal ahead of the face, the powered support, and the caved waste to be three yielding foundations which interact to control the subsidence of the roof strata.The caving mechanisms identified for the strata of the Hirst and Bulli seams, are different. These mechanisms being related to rock properties - the palaegeography and depositional conditions at each site-produce caved wastes with different yield characteristics.An analysis of the results obtained for convergence and support reaction during production cycles at both sites shows the manner in which support reaction is developed, indicating the importance of higher setting load densities in the Bulli seam.Evaluation of the work done on the subsiding roof strata during typical production cycles by two of the yielding foundations the powered support and the caved waste immediately behind the powered support - further demonstrates the influence of caving mechanisms on support rating.

Jan 1, 1989

By Watson F. G

As an introductory paper of a series on the Melbourne (Australia) Underground Rail Loop extension to the extensive electrified suburban railway system the paper outlines the need for the Loop, legislative background, organizational establishment, engage- ment of consultants, design control, contracts, financial aspects, example of organizational flexibility and certification and transfer of the Loop to the Victorian Railways Board.

Jan 1, 1981

The Malvern Hills coal project is now in an advanced stage of development with the stripping of overburden from above former underground workings in which a 3 m seam of subbituminous C coal with very low ash and sulphur was previously mined. The main seam dips at 45¦ to the south-east, along with other adjacent potentially recoverable thinner seams, and the strike extent of past coal mining in the Malvern Hills approaches 10 km with most extraction by underground methods. Overburden and interburden is predominantly weak mudstone, with only very minor sandstone, whilst a 1 - 2 m thick veneer of Last Glaciation loess covers the area. The coal product from the present mine site will supply the local industrial market, with production planned to peak at about 20 000 tpa. Settling pond design has been based on several different approaches, including an estimate of likely inflows from the contributing catchment of about 5 ha under predicted storms having a ten year recurrence interval. A pond of about 1000 m2 in area has been constructed with its invert in mudstone bedrock, and soil slopes have been lined with lime-stabilised clayey loess silt incorporating a gravel armour layer. The pond outflow takes place via a 2 m high 1.8 m diameter concrete dewatering tower, with a skimmer arrangement to lower the pond by approximately 500 mm between storm events. The overflow water discharges to the main stream above a natural wetland, which will act as a secondary polishing pond, and this is to be enhanced in conjunction with the neighbouring forestry company. Discharge consents specify turbidity and pH as the controlling criteria, and both will be monitored at the settling pond discharge point as well as at the entry to the main stream. Investigations to date indicate that the pH of water exiting from previous underground workings is in the range 6.8 to 7.2, and that acidic drainage will not be an issue with this mine site. No dispersive clays have been identified in assessing the overburden and batter materials, although erosion during storm events is expected and all drains will ultimately be routed through the main settling pond to ensure adequate control of runoff-generated sediment. Reestablishment of vegetation on cut and fill batters remains a priority, and ongoing monitoring will ensure satisfactory long-term performance of the pond system.

Jan 1, 2003

By Morland R

In the course of an exploration program aimed at increasing Pasminco Mining's ore reserves, an electromagnetic survey down one of the underground drillholes at the North Mine, Broken Hill, recorded a broad and persistent response. This paper demonstrates that the anomaly was not due to any geological feature, but rather was caused by 'self-response' of the sensing probe. The observed results are due to the surveyed hole lying within a resistive environment and having distinct, but not unusual, changes in dip.This phenomenon has not been widely reported and we believe that there are likely to be similar cases in company records where very genuine looking responses are due to self-response rather than sulphides. These false anomalies can be recognised by correlating the observed data with the calculated down-hole component of the transmitting loop's primary field.

Jan 1, 1994

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 Koeng R, Richardson M, Hoare R

A discrete event computer simulation model was developed for two of the stoping methods currently used at the Z.C. Mines Broken Hill oper- ations. The objective in undertaking this project was to provide an effective tool for mine planning and design to allow comparisons of alternative extraction strategies and attempt to optimise the allocation of capital equipment and human resources. The Slam II simulation program was used in conjunction with ,a com- monly used data editor, text editor and graphics package to allow the simulation to be done on a personal computer with minimum training requirements. The computer hardware used was a portable computer cur- rently available using 80386/20MHz electronics. Specific logic techniques were developed to allow the Slam II language to simulate mining opera- tions because it was originally developed for manufacturing and com- mercial simulations. The design of the model was based on observations and a data collec- tion campaign. The model was designed with flexibility which allows simple editing of the input data which includes: - Insitu volumes - Development statistics -Loadout efficiencies -Loader speeds, availabilities and capacities -Chute numbers, volumes, distances and blockage statistics -Trucking statistics -Work schedules -Utility statistics

Jan 1, 1988

The Bellambi Coal Company Limited com menced longwall mining at South Bulli Colliery in 1965. At present it operates three long- wall units in two seams. Although results to date have been less successful than planned, it is apparent that this type of mining has tremendous potential in the particular conditions at South Bulli. Massive sandstone strata above the Bulli seam is the controlling influence on face conditions. The earliest equipment proved to be inadequate and the Company has progress- ively replaced and upgraded the roof supports and ancillary equipment so that the present units are capable of producing high and consistent outputs.

Jan 1, 1976

By D Fargher

BHP BillitonÆs Cannington operation began production in 1997 and is presently the largest tonnage and lowest cost single mine producer of both lead and silver in the world. The original design capacity was 1.5 Mtpa and this has progressively increased via a series of debottlenecking projects in both the mining and milling operations. In 2003, 2.39 Mt of ore was mined, whilst 2.31 Mt of ore was milled. In February 2003 Cannington received approval to expand the project to a sustainable capacity of 2.4 Mtpa. This resulted in underground development into the northern zone, upgrades to the concentrator, increased accommodation at site and power station capacity. The Cannington project development team implemented a partnership approach to the project. Fraser Osborn Engineering and Outokumpu Technology worked closely together with the Cannington team to meet all of the project constraints.

Jan 1, 2004

By Barber J

The manganese ore of Groote Eylandt is a shallow sedimentary deposit of Cretaceous age. There are a number of deposits which vary greatly in ore texture, density, percentage of matrix and thickness. The thickness in the present five operating quarries varies from 1-5 metres. The mine output in 1973 was 3 million tonnes of which 60% was blasted, the remainder ripped and bulldozed. The shallow deposit and its varying thickness create rather unique blasting problems which must be overcome in order to produce a minimum overall mining cost but not necessarily resulting in a minimum drilling and blasting cost per tonne. Future planning envisages the introduction of site mixed slurry explosives following test work and the application of a twin boom single operator rotary percussion drill. The paper outlines the overall developments,present and envisaged practices and the reasons for these changes.

Jan 1, 1974

By M I. Pownceby, S P. Suthers, V Nunna, G J. Sparrow

Global demand for iron and steel has increased substantially over the past 20 years and there has been a greater focus on developing suitable processing options to treat low-grade hematite-goethite ores containing higher levels of silica and alumina impurities. The processing applicable to reduce the impurity levels in these lower-grade iron ores depends on their mineralogy and a thorough understanding of the process dynamics associated with the separation technology. Different separation technologies used to remove silica and alumina from low-grade iron ores were reviewed. The major concentration methods that may be applied to upgrade lower-grade lump iron ores include magnetic separation, wet and dry heavy media separation, and air-pulsed jigging. The technologies applicable to beneficiating iron ore fines include wet and dry gravity and magnetic separation, flotation, and roasting followed by magnetic separation. It is necessary to investigate the application of separation technologies on a case-by-case basis to select economically viable beneficiation strategies suitable for the particular low-grade iron ore. A commercial flow sheet is expected to involve the implementation of several separation technologies.

Nov 8, 2021

By E R. Ramanaidou

Two unknown iron ore samples were found by a geologist from Ok Tedi Mining Limited copper, gold and silver mine at an old wharf site dedicated to a 1970s drilling program in Lake Murray in Papua New Guinea (PNG). These iron ore samples could not come from a PNG mine and it was decided that a study should be undertaken to understand their origin. Lake Murray is the largest lake in PNG with a total surface area of 647 km2. It has a high-water 2038 km long convoluted shoreline with seasonal water level changes (Osborne, Kyle and Abramski, 1987) and it is located around 200 km south of the Ok Tedi mine (5°13’25”S, 141°09’37”E). The petrology, mineralogy and chemistry of two Fe samples (Ok Tedi 1 and Ok Tedi 2) included optical microscopy, X-ray fluorescence (XRF) analysis and a comparison with worldwide iron ore deposits. The two rock samples were cut to produce two subsamples: (1) a polished thin section; and (2) a pulp that was used for XRF analysis including major, minor and trace elements. Ok Tedi 1 and Ok Tedi 2 were petrologically and chemically compared to a range of known iron ore samples from Australia, Brazil and South Africa. The petrological study of Ok Tedi 1 indicates that it is composed of granoblastic recrystallised hematite and the overall texture is uniform without any obvious original ‘sedimentary’ texture. Ok Tedi 2 is a ‘specular’ or platy hematite with recrystallised and fused grains. Using both petrological and chemical clues, the two Ok Tedi samples likely originated from the Iron Quadrangle in Brazil.

Sep 18, 2023

By E J. Hill, F Huang, A Otto

Geochemical data from drill core samples is used in mineral exploration to enable geologists to understand subsurface geology. However, it is challenging to analyse these data sets rigorously and consistently. Manual data interpretation relies on the knowledge and experience of logging geologists. When multiple geologists are involved, it is possible to introduce inconsistencies in logged lithology type and scale of logging (‘splitters’ versus ‘lumpers’). Machine learning (ML) is a powerful tool for analysing high dimensional data (ie data with many variables) and large data sets (ie data with many samples). However, ML methods applied to drill hole samples do not incorporate spatial information and this can result in high misclassification rates and small-scale ‘noisy’ results. We demonstrate the use of multiscale spatial analysis (wavelet tessellation) as a pre-ML step to analyse spatial information. This step helps reduce misclassification and filter out unwanted small-scale variation in the data. In an experiment, we used wavelet tessellation and supervised ML to predict litho-geochemical rock types from geochemistry data. The data set is from the Valhalla uranium deposit near Mount Isa, northern Queensland. First, geochemical knowledge and statistical analysis was used to select appropriate geochemical elements for litho-geochemical classification. Second, the elements were processed using multiscale spatial analysis. Third, we trained a Random Forest model with the data set and found that the model performs worse in predicting rare rock samples than common ones. We applied over-sampling and down-sampling methods in aim to overcome this issue. As a conclusion, the combination of multiscale spatial analysis (to define rock unit boundaries) and Random Forests (to classify rock units) is a good method for rapid and accurate analysis of drill hole geochemistry.

Mar 22, 2022