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Tin mining has taken place in the New England region of New South Wales since 1872. Until fairly recent times there was little pro- vision made for environmental protection. Mining methods,which included ground sluicing and open cutting,had considerable environmental impact. Much of the topsoil was lost and there is little vegetation on the infertile and at times toxic, subsoil. Thus much of the lands disturbed by mining have not been stabilised and are eroding, causing extensive pollution of adjacent watercourses. There are more than 1500ha of abandoned tin mine sites in the New England, representing one of the worst rehabilitation problems in New South Wales and reflecting poorly on the mining industry as a whole. Recent tin mining operations incorporate progressive rehabilitation in their mining cycle. Topsoil is stockpiled and later respread. This topsoil contains a seed source, facilitating revegetation and thus stabilisation. The tin mining industry, under considerable cost pressures at present, is seeking a cost- effective revegetation technique. Most of the mines in the New England are situated in a forest environment. Trials have been conducted in the past using exotic pasture species with limited success due to the characteristics of the subsoil. Other revege- tation trials have used pine or eucalypt tree species. The cost of these techniques is a major disadvantage. Certain acacias species were observed colonising disturbed tin mining areas on very infertile subsoils. Acacias have a number of characteristics indicating a possible applic- ations in mine rehabilitation programmes.

Jan 1, 1987

The control of industrial grinding circuits in Australian concentrators has been practised for many years in one form or another. Some have established simple feedback loops in areas such as fine ore bin feeders (tonnage control), mill pump sump levels (flow control) and water additions (density control). There are also some sophisticated systems which infer circuit product size using complex measurements of mass flaws and water additions in the circuit and attempts are made to control those flaws to produce a constant circuit product size. The inferred size method in Australian concentrators has become firmly entrenched in the last ten years and control techniques involving the use of direct size measurements with reliable on-stream sizers have been Ignored.

Jan 1, 1983

By T Ross, S Cameron

The requirement to use explosives in ground temperatures exceeding 50¦C is becoming more common as mines work to maximise the recovery of their resources. Orica Explosives was requested to assist in the development and implementation of æhot blastingÆ safe working procedures at Liddell Coal Open Cut in the Hunter Valley. The mine operator, Hunter Valley Earthmoving (HVE), had to contend not only with elevated temperatures in their overburden resulting from burning coal beneath, but also old underground workings which tended to exacerbate the problem. The paper discusses the following issues:the consultative process that was used to develop the procedures employed to ensure the process could be carried out safely; the technical issues surrounding blasting in hot ground, including temperature monitoring, product selection, application and design to ensure safety and performance were maintained; the need for confidence and trust in the team that was working together in a potentially hazardous environment, the emotive issues that were encountered and how they were addressed; the value of a regular review process combined with open and honest communication to ensure the procedures represented best practice and that all stakeholders understood the process; and the value delivered to Liddell Coal when sterilised areas of coal became accessible with little disruption to the mining process. The paper also discusses the challenges that were encountered in the Reservoir Block where proximity to major power lines and rail infrastructure meant that hot blasting procedures had to also consider vibration limits and the need for Energy Australia to disconnect the power.

Jan 1, 2001

By Ketelaar P. B, Nichols S, Power W. L, Utley D. C

The impact computers are having in geoscience is distinctly mixed. In the petroleum industry where much of the data are based on geophysics, computers have become an integral part of exploration and reservoir evaluation and simulation. In the minerals industry, the trend to computerisation is more advanced in some disciplines than others. Geophysical and remote sensing data are routinely processed and imaged using state of the art computer techniques. Mine surveying, planning, design and resource and ore reserve estimation are now all predominantly reliant on computers. However senior management of many companies, particularly in the mineral exploration industry, are still reticent to fully embrace the technology. 3D computer modelling of geology and orebody delineation is still largely in its infancy. Two current and significant drawbacks to the routine use of computer modelling of geology in both mining and exploration are the tedious and time consuming modelling process and the lack of seamless interaction between 3D computer-aided drafting (CAD) software and geographical information systems (GIS) which are largely 2D in their data treatment. There is an urgent need for a 3D spatial information system (eg 3D GIS) with intelligent and rapid modelling functionality. One of the keys to the successful building of 3D geological computer models begins with data base structure and design to ensure that there is no loss of data fidelity through data capture, storage, manipulation and modelling. Once a model is constructed, the latest generations of visualisation software provide sophisticated environments over a range of hardware platforms for visualisation in both mono and stereo viewing. This is demonstrated by the geological models which are presented in the digital interactive version of this talk whose URL on the World Wide Web is: http://www.ned.dem.csiro.au/FRACTAL/pubs/talk97AUSIMM/

Jan 1, 1997

By L Grigorov, G J. Jame, A V. Nguyen

The dewetting kinetics between a small air-liquid interface and a silica (negatively charged in water) planar surface in solutions of dodecylammonium chloride (cationic surfactant) has been investigated using the Scheludko cell and digital high-speed video microscopy. The gas-liquid interface was created at the bottom of a small silica capillary of the cell and then was moved towards the silica planar surface. After the rupture of the liquid films between the interfaces, the expansion of the gas-liquid-solid three-phase contact (TPC) line was observed and recorded using a digital high-speed video microscope system, operating at 1000 frames per second. The surface tension of the surfactant solution was measured using the pendant drop technique. The equilibrium contact angle was measured using the Scheludko-Minings method with a silica micro-sphere. The TPC radius was determined as a function of time and compared against the available hydrodynamic and molecular-kinetic models. The experimental data are described very well by the molecular-kinetic model for the TPC line motion. The hydrodynamic model is in agreement with the experimental data only for a short time after inception of the three-phase contact expansion.

Jan 1, 2005

By J Rostami, D Tadic

While hard rock tunnel boring machines (TBMs) have an established track record in the tunnelling industry, accurate estimation of TBM performance for each specific project remains critical. Machine performance prediction is required to assist planning activities, including costing and schedule preparation, machine specification and effective planning of maintenance and repairs. In addition, monitoring machine performance during the construction period is required to assess and manage excavation progress, and to achieve optimal advance rates based on specific geotechnical conditions exposed during excavation. TBM performance analysis can also contribute to the development of more accurate performance prediction models for future applications. Rock mass characteristics play a dominant role in machine performance. This paper offers a review of the impact of rock mass characteristics on TBM penetration rates for two specific tunnelling projects. A discussion is provided on the results of statistical analysis of available field data, including geological back mapping, rock properties and measured rates of penetration (ROP). The analysis offers a comparison of the achieved and predicted ROPs to provide a better understanding of the influence of rock mass properties on the performance of hard rock TBMs. A new rock mass adjustment factor is introduced to enhance the accuracy of an existing prognosis model for use in jointed rock masses.

Jan 1, 2008

By C J. Larder, S E. Turner

The concept of underground grinding is not new, but to a metallurgist and a mining engineer this could be considered unconventional. The idea of pumping a ground slurry several hundred metres from underground in a single lift could also be considered to present a daunting engineering challenge. Using a practical example of a mine in Australia where the owners have requested not to be identified, this paper challenges the conventional thoughts on these concepts and shows that with basic sound engineering practices the production of a ground slurry from underground could potentially provide significant operating cost savings. The supply of ore from the underground mine is currently drawn from depths approaching 800 m below the surface. The cost of hauling the ore to the existing underground crushing station located 500 m below surface has been steadily increasing. A number of alternatives to reduce the mining and processing unit operating costs were examined by Sinclair Knight Merz (SKM) and the mining company. The most radical of these is the use of hydraulic hoisting of ore at an increased production rate. Numerous questions were asked, such as: How does one get a SAG mill or an HPGR crusher underground? Where does one locate a grinding mill underground? Does the technology exist to pump the slurry to surface in a single lift? What will be the cost benefits? What are the risks involved? The study covered the two main technical issues underlying the potential benefits. Firstly, technical evaluations were undertaken on the pumping technology currently available for single and multiple lifts to surface. Secondly, the issues relating to the feasibility of delivering and locating a SAG mill underground were reviewed. Although the capital costs for this project are significant, the operating cost savings showed a potential payback period of less than two years, and furthermore provide the basis for an increased mine life, especially at lower metal prices.

Jan 1, 2005

The object of this paper is not to describe any particular type of engine in close technical detail but rather to give a general picture of past and present practice in this important section of the industry. The subject involves the study of almost 600 years of coal mining history which has fluctuated from stagnation to extremely rapid progress.Up to the year 1300, coal was obtained from outcrops and exposed beds, but this easily worked source soon gave out, so by that time shafts had to be sunk to the coal seams, and coal mining proper commenced its career.These early shafts were very shallow, and winding equipment was not a matter for much concern. Raising coal was generally achieved by human labour, which was called "coal bearing." Coal was loaded into baskets. strapped to a man's back, and carried from the underground workings to the pit bottom. The unfortunate individual then climbed ladders to the top of the shaft, unloaded the basket, and descended the shaft for the next load. Men, women and even children, were employed as the mine expanded, and were generally bound to the colliery for life, performing daily work which would now be regarded as slavery. This primitive method of raising coal to the surface was slow, inefficient and highly dangerous, yet for want of a better method it continued until in 1602 it isrecorded as having been abolished in Wales, one of England's great coal districts. It was not until 100 years later, however, that it was abolished in the northern coalfields, and the colliers were freed forever from their dreadful life.WINDLASSThe first step towards winding coal was the introduction of the windlass. This was similar to the common windlass used over a well, and was operated by man power. The...

Jan 1, 1945

THERE is available a considerable amount of literature concerning the practice, and, to a smaller extent, the theory of ventilation as it applies to coal mines. Publications considering the subject of ventilation of metal mines from a practical viewpoint are much less numerous, whilst the treatment of the theoretical aspect of the question (except in so far as is common to coal mining) appears to have been almost neglected. This may be due to one of two causes (a) That in many metal mines (especially those which have not attained a great depth), on account of the greater number of connections with the surface, as compared with coal mines, natural ventilation has sufficed.(b) That in metal mines where the foregoing is not the case the solution of the ventilation problem from theoretical considerations has been regarded as involving so many complications that any attempt at the determination of a set of concrete ventilation figures applying to and throughout the mine would be futile. Whilst it is freely admitted that the difficulties inherent in the application of theory to the ventilation of metal mines are numerous, it must also be admitted that few attempts have been made to overcome them. The ultimate aim, of course, would be the collection of sufficient data to enable the probable behaviour of the air-currents throughout the whole of the workings of any mine to be accurately predicted under any particular set of circumstances. Failing the attainment of this goal of perfection, it would at least appear that much valuable information might be obtained. In ventilation, as in...

Jan 1, 1921

It is a commonplace of our industry that prices of most minerals have been historically weak during the 1980s. The International Monetary Fund's index of prices of metals fell 25 per cent between 1980 and 1982, rose slightly in 1983, and has since fallen further. In December last year it was 37 per cent below its 1980 average. The few temporary exceptions to the mineral industry's malaise highlight the excess capacity, which largely explains the weakness of prices. The industry has painfully come to recognise that more satisfactory prices will not be restored until supply capability and demand move back into better balance. Mine capacity was installed in the expectation of much faster growth of demand than has occurred. For a variety of reasons mine and plant closures have been insufficient to restore equilibrium to the market-place. The industry may, therefore, have to resign itself to continued weak prices for some years more, at least by the yardstick of the 1970s. Growth rates of demand have slackened off in line with economic activity, and in response to continuing substitution and technological improvements. To the extent that the recent weakness of oil prices stimulates the industrial countries' activity, demand for non-fuel minerals may grow faster than most forecasters now predict. It is, however, much too early to say how long the weaker oil prices will persist, and even more difficult to estimate their probable effects. In typical post-war business cycles the usual response to recession was to batten down the hatches, and ride out the storm. Sooner or later, and probably sooner, demand resumed its previous trend path, and prices recovered. The market, in effect, bailed mines out of trouble; the more efficient could make attractive pre-tax profits whilst even the poor to mediocre could earn a satisfactory living. Prices rose at least as fast as general inflation, and in the early 1970s much faster. In retrospect those price rises of the early 1970s were historically abnormal but they did not appear so in the prevailing inflationary climate of the time. When the market failed in the early 1980s many of the hardest hit companies looked for scapegoats.

Jan 1, 1986

Structure is the most important control on the location of hematite deposits in the Hamersley Province in the Pilbara region of Western Australia. Unravelling the structural history of mineralised areas, however, is complex because the Province underwent three orogenic events, and three regional extension events followed the main episodes of compression. Steeply E to ENE dipping normal faults immediately predated deposition of the Beasley Quartzite of the lower Wyloo Group after the Ophthalmian Orogeny. Steeply NE and SW-S dipping normal faults predated deposition of the McGrath formation of the middle Wyloo Group, following the Panhandle Orogeny. The resulting interpreted rift was subsequently reactivated and tilted during the Capricorn Orogeny. Late NE trending normal faults are confined to the eastern half of the Province. High-grade hematite deposits occur in rocks that range from intensely folded (Mt Whaleback, Giles Mini) to rocks with less, or only little deformation (Paraburdoo, Channar), suggesting that folding had at best limited influence on ore genesis. In contrast, extensional normal faults are always associated with high-grade hematite deposits, and in particular faults that link the underlying dolomites of the Wittenoom Formation with the overlying iron formation, thus providing a pathway for mineralising alkaline fluids.

Jan 1, 2005

By M P. Schwarz

In recent years, computational fluid dynamic (CFD) modelling of mechanically stirred flotation cells has been used to study the complexity of the flow within the cells. In CFD modelling, the flotation cell is discretised into individual finite volumes where local values of flow properties are calculated. The flotation effect is studied as three subprocesses including collision, attachment and detachment. In the present work, these subprocesses are modelled in a laboratory flotation cell. The flotation kinetics involving a population balance for particles in a semi-batch process has been developed. From turbulent collision models, the local rates of bubble-particle encounters have been estimated from the local turbulent velocities. The probabilities of collision, adhesion and stabilisation have been calculated at each location in the flotation cell. The net rate of attachment, after accounting for detachments, has been used in the kinetic model involving transient CFD simulations with removal of bubble-particle aggregates to the froth layer. Comparison of the predicted fraction of particles remaining in the cell and the fraction of free particles to the total number of particles remaining in the cell indicates that the particle recovery rate to the pulp-froth interface is much slower than the net attachment rates. For the case studied, the results indicate that the bubbles are loaded with particles quite quickly, and that the bubble surface area flux is the limiting factor in the recovery rate at the froth interface. This explains why the relationship between flotation rate and bubble surface area flux is generally used as a criterion for designing flotation cells. The predicted flotation rate constants also indicate that fine and large particles do not float as well as intermediate sized particles of 120 - 240 ¦m range. This is consistent with the flotation recovery generally observed in flotation practice. The magnitude of the flotation rate constants obtained by CFD modelling indicates that transport rates of the bubble-particle aggregates to the froth layer contribute quite significantly to the overall flotation rate and this is likely to be the case especially in plant-scale equipment.

Jan 1, 2005

By R S. Suglo, G-K Er

Mineral processing is an essential component of a mine production chain and it accounts for significant proportion of the production cost. Over the past decade, significant research progress has been made in processing plant efficiency using theoretical, experimental and simulation modelling techniques. However, these studies are limited to process plant system as stand-alone units with no interactions with the mining units. In order to maximise the total mining system efficiency and more accurately simulate the system, the processing plant must be modelled as part of an integrated mining system. This becomes increasingly important in continuous surface mining systems, with limited ore processing capacity. In addition, plant efficiency is roughly estimated with known parameters or with simplistic statistical data, without regards to the stochastic processes governing these parameters, such as processing plant feed introduction. In this paper, a comprehensive model of the ore processing plant system is given and the object-oriented design (OOD) of the system is briefly introduced. The joint operation of ore processing plant system and haulage system is analysed. Numerical modelling is used to analyse the ore processing plant system under different conditions. Analysis of the results show that the optimum plant capacity is 0.7 tons/sec (2520 tons/hour). The results also show that the plant system resources cannot be fully utilised because the production rate is always less than the plant capacity. When plant capacity reaches an optimum value 0.7 tons/sec, the production rate is about 0.64 tons/sec. The underlying stochastic processes associated with plant and mine capacities cause this variability. In order to reduce this variability, there is the need to tightly set tolerances for the function variables.

Jan 1, 2003

By M P. Schwarz

This paper describes modelling studies of the flotation cells used by BHP Billiton Nickel West Ltd in the slimes circuit at Mt Keith. The aim is to achieve a better understanding of the hydrodynamic limitations in the existing cells to improve nickel recovery. Computational fluid dynamics (CFD) simulations have been performed on the 100 m3 mechanically-stirred cells. The data produced by the simulations include velocity vectors, gas holdup distribution, solids distribution, bubble size, superficial gas velocity and turbulent parameters. These results have been checked and found to match hydrodynamic measurements at the plant. An analysis of the data found that one of the limitations in fine particle recovery was related to the air bubbles discharged with the tailing. The air in the discharge was caused by the high viscosity of the pulp. In the presence of fine particles, the pulp exhibits high viscosity with a yield stress. The increased drag due to high viscosity caused the bubbles to rise more slowly up the cell. This results in a significant hold-up of bubbles, some of which report to the tailing with associated loss of valuable minerals. A parametric CFD study of the operating variables shows that less air would be discharged in the tailing by decreasing the following: air flow rate,pulp density,stirring speed, andfrother addition. Simulation results indicate that these changes would cause a lowering of the air hold up in the cell especially near the discharge area. Predictions of the bubble-particle attachment rates under various operating conditions have also been calculated. Although it is possible to increase attachment rates by increasing stirring speed or by increasing pulp density, the amount of air discharged and the amount of nickel loss through the tailing will also increase. The project showed that CFD modelling is a powerful tool for studying hydrodynamic effects of bubble-particle interactions in flotation cells.

Jan 1, 2008

By Thomas R. J

Following asmallnumberofpollutionincidents involving the death of cattle from ingestion of cyanide that had escaped from gold processing plants, the Queensland Government undertook to develop competent guidelines addressing this problem. These guidelines, "Queensland Government Guidelines on Prevention of Water Pollution from Cyanide Use in Gold Ore Processing", issued by the Department of Environment and Heritage, Department of Resource Industries and Water Resources Commission, cover hydrology and general house-keeping intended to reduce the likelihood of significant impact from a spill or unintentional dis- charge of contaminated material. There are three major advances for Queensland embodied in this Guideline: ò the use of a design approach that gives site specific standards rather than trying to give a multitude of standards broad enough to cover all situations, ò the use of hazard assessment and a "critical period" hydrologi- cal design technique, and ò new monitoring and reporting requirements. The guideline is presented here in a summary form:

Jan 1, 1991

By A Keddie

Standard microeconomic theory suggests that the behaviour of mineral extraction and processing firms with respect to their demand for water can be modelled and a market demand for water subsequently derived. Such a model, although an abstraction of the real world, should be able to predict the responsiveness of quantity of water demanded to change in price, and, change in demand to a range of factors including: expectations about reliability of supply, changed commodity prices for mineral production, and change in water technology and storage at mine site. This paper demonstrates that the price of water is particularly responsive to changes in demand and that although price increases would result in some additional supplies, physical constraints on supply suggest that the industry will be paying considerably higher prices for water in the future. It is recommended that the mining industry undertakes quantification of possible price increases to position itself to minimise the impact on their operating costs as well as to make responsible capital investment decisions to facilitate future expansion or commissioning of new mines. Substantial investment is required to commission a new mining venture with expected rates of return subject to risk and uncertainty due to fluctuations in world commodity markets as well as reliability of secure supplies of inputs. If a reliable supply of water was subject to uncertainty and water was a critical input for production, then the initial mine design would typically consider a range of production decisions contingent on levels of uncertainty with respect to water supply. These states or sets of water supply, will affect production decisions and future water demand. Modelling production decisions contingent on different states of nature, termed the state-contingent approach, provides a number of insights about producer behaviour under uncertainty. This paper investigates the assumptions underlying the derivation of the market demand for water by the mineral resource industry and identifies the drivers of demand and the responsiveness of the industry to change in price and supply, particularly in relation to capital investment in water-use technologies. The usefulness of these models to the mining industry is considered by reference to the increasing demand for water by the industry in Queensland, in a climate of water shortages.

Jan 1, 2006

By R Huntley, D Sims

Pajingo gold mine produces over 240 000 oz Au per year from underground mining using longitudinal bench stoping methods with a 15 m sublevel interval. Average mine head grade is around 12 g/t Au, contained within quartz veins between 0.5 to 16 m wide. The veins dip steeply (>60¦) and exhibit strike variations which lead to many curved and meandering drive/stope geometries. Unplanned dilution at Pajingo is predominantly controlled by fault planes that subparallel the vein and commonly lead to slabbing failure from the stope walls. Initial efforts at determining maximum spans were based on using the Stability Graph method of stope stability. However the method had a number of shortcomings that did not address mine site observations, including previous mining, interaction of different joint sets and the presence of discrete shears which resulted in poor prediction of stability. A method was developed to rate the risk of dilution for a stope based on observations made in the ore drives. The method utilises profile mapping of the ore drive, structural features observed and the orebody itself, on 10 m spaced sections along the ore drive. A matrix of factors determines the dilution risk for stoping at the time of mapping and the rating is transferred to longsection plots in the office. The dilution risk rating is used to determine the position and density of cable bolt support aimed at lessening the risk, and can be used to review blasthole designs prior to finalisation. The method has been used for more than two years and has proven to be a good indicator of potential unplanned dilution (ie waste outside of ring design). A recent review of the dilution risk mapping process has indicated it is assisting in reducing the impact of dilution at the operation and has the scope to be utilised further in the design process.

Jan 1, 2002

By Seymour D

The disagregation and privatisation of the mining and power gene ration operations of the former State Electricity Commission of Victoria has being taking place over the past five years. This has transformed the service provision to the new organisations and has resulted in major change to the working lives and professional relationships of thousands of Australians. The authors wish to take this opportunity to explore the issues arising as the program of privatisation of public assets continues. Changes within the workplace which resulted from the outsourcing of the 'investigation and design' functions and more lately as a result of privatisation of the operating, generating and distribution businesses are discussed. The responsibility of managers retaining the services of design engineers has changed. There is an added responsibility of contract administration and an increased focus on intellectual property and strategic issues. The way in which the sectors are adapting is discussed and future directions are explored. We welcome this opportunity to explore the changes in professional life which have taken place over the last five years in the Latrobe Valley Power industry. Engineers and earth scientists have a pivotal role in the continuing successful operation of the three Latrobe Valley Mines of the generation companies. The Mines' collectively excavate annually over 13 million cubic metres of overburden and 48 million tonnes of coal for delivery to mine-mouth power stations and for briquette manufacture.

Jan 1, 1997

Results are presented of the investigation of gas dynamics of the blast furnace process obtained on laboratory models and operating furnaces. Gas residence times were measured using a helium tracer technique developed for the purpose. Residence times were determined in furnaces of 1007 m3 and 1719 m3 and results used in the calculation of the burden parameters and to estimate the distribution of the gas flow along the furnace radius. The effect of tuyere injection of coal dust on gas distribution was also investigated and the advantage of continuous injection compared with intermittent injection is noted. The unevenness of gas distribution across the furnace area is found to correlate well with differences in the size analysis of the iron-bearing component of the burden. The mixing of the gas streams between the neighbouring raceways was studied. It is shown that in the central region of the furnace gases from every tuyere are mixed together, whilst in the peripheral regions mixing is more localised and includes only the sections consisting of five adjacent tuyeres. A solution is proposed to the problem of a theoretical evaluation of the critical gas velocity. A simple relationship between the Reynolds and the Archimedes numbers was obtained from which, after substitution of the burden size data and the gas parameters, it is -possible to evaluate the critical gas velocity. Conclusions include information relating to the optimisation of the gas distribution and views on reducing gas injection at elevated furnace levels.

Jan 1, 1975

Permian ultramafic and associated rocks form a belt in East Nelson and contain widespread, but minor, chromite and copper mineralisation and some mining was carried out last century. Since mining ceased, about 1910, little mapping of the belt has been carried out although its origin has been debated vigorously. Recently it has been inferred to form part of a ophiolite sequence, which has been tectonically disrupted to form a melange, and several 'plate -tectonic' models have been proposed. Mapping in the central part of the belt has shown that mTlanges are to the east of the ophiolite sequence. Faulting is widespread so that in anyone section part of the sequence may be absent. Some of the faulting is difficult to recognise and probably took place during or soon after the sequence accumulated. Other faulting is clearly of Cenozoic age and includes major NNE striking faults, with large horizontal displacement, and approximately east-west striking faults with almost entirely vertical movement. The writer agrees that 'plate tectonics' could provide an acceptable explanation for the origin of the ophiolite sequence but the models so far proposed do not take into account the nature and field relationships of the rock units present. Copper Mineralisation is largely controlled by the younger faults, particularly those striking about north-east, and is largely confined to the western part of the ultramafic rocks particularly where slivers of the volcanics of the adjacent Lee River Group are enclosed. Mineralisation, along NNE striking shear zones, has recently been found in the volcanics some distance from the ultramafic rocks. The chromite mineralization is in the form of primary layering in the basal part of the ultramafic belt although in places it has been concentrated into lenses probably during serpentinisation.

Jan 1, 1977