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Study on Flotation Experiment of Complex Copper-Lead-Zinc Polymetallic Sulfide Ore in High Altitude Area and its Industrial Application

Sep 13, 2010

By D Wyborn, P A. Dowd

The characterisation of rock fracture networks is an important component of rock engineering applications involving stability assessment or fluid flow analysis. However, the derivation of a reliable rock fracture model remains a very challenging problem in practice. This paper describes a Bayesian framework, in the form of Markov Chain Monte Carlo (MCMC) simulation, for the construction of such a model. Model conditioning using different data sources is discussed including seismic events recorded during hydraulic fracture stimulation, rock face fracture mapping data and downhole geophysical survey data. The freeware FracSim3D is used for the simulations.

Sep 26, 2011

By M Oyarzún

Direct relationships between rock texture and BWi (grindability index) have been established based on geological and metallurgical information supported by optical microscopy observations, gathered from 731 samples.Each recognised rock texture is observed to be related to a certain BWi range and, this texture is also characteristic of distinct lithological subunits (recognisable at mapping scale). Therefore, this relationship may provide an important tool for early milling in situ estimation.Since each textural type is a response to rock formation conditions, the causality of the relationship between BWi and texture is based on such conditions and, particularly, on the interfacial free energy among its components.According to the abovementioned textural features, the greater the free interfacial energy between mineral components, the greater the necessary energy required to break its grain boundaries and, consequently, the greater the necessary energy required for milling.If the textural evidence indicates that the rock was able to adjust the shape and/or size of its components – in a natural tendency of all systems to minimise energy– then the necessary energy required to break its grain boundaries will be lower.

Sep 5, 2011

By Y Wang

Inadequate goaf gas control may lead to gas exceedances in the ventilation return air, which will trip power in longwalls and cause production stoppage. To effectively control gas emissions, Australian mines heavily rely on drilling vertical goaf holes to capture coalmine methane before it migrates to mine openings. The wide application of goaf gas drainage may change the goaf pressure distribution, lead to more ventilation air leakage, and consequently increase gas explosion and spontaneous combustion risks. This paper focuses on analysing goaf gas drainage production data from a case study longwall mine in Australia. The correlation between suction pressure, total flow rate, gas flow rate and air leakage rate were analysed in detail as the face-to-hole distance changes. Suction pressure is found to be positively correlated with total flow rate, and their correlation also varies at different goaf locations due to various goaf compaction and flow resistance. This paper also proposed a theoretical method to calculate the goaf resistance of ventilation air leakage pathways. Based on several basic assumptions and different goaf drainage scenarios, the leakage airflow pathway resistance in the goaf at different face-to-hole distances can be calculated. The model results suggested that the resistance of air leakage pathways from the working face to individual goaf holes increased with the face-to-hole distance. The resistance results can also be used to calculate the corresponding permeability at the same position, which can be used as input data for CFD or Ventsim models.

Oct 12, 2022

By S Robotham, P C. Stewart, K Maher

A data science based dilution study was conducted to identify the causes of dilution at South32’s Cannington Mine (Cannington), a large open stoping operation. In terms of industry benchmarks for unplanned dilution, Cannington is already performing very well, and so opportunities for improvement are more difficult to identify. The study is based upon back analysis of nearly 150 case studies from the mines reconciliation database, and has quantified the relative effect and significance levels for the following dilution parameters; time until paste filling, faulting and cable bolt reinforcement. Specifically, significant contributions were associated with faults and stope open duration. Quantifying the effect of faults on stability graph accuracy enabled a site specific adjustment to improve the predictive ability of the Cannington stability graph (unstable stope specificity improved from 63 per cent to 74 per cent). Despite Cannington’s already high levels of stope performance compared to industry benchmarks, data science methods have identified a complex interaction between identified dilution factors (ie stope open duration, presence of faults and cablebolting). Specifically, a third order Factorial ANOVA (Analysis of Variance) provided evidence that stope open duration reduces the effectiveness of cable bolts in faulted ground (average dilution = 2.1 m, p-value = 0.13). These results are consistent with site observations of a relationship between the stope open duration and the extent of failure when unravelling on a fault, even when cables are present.CITATION:Maher, K, Stewart, P C and Robotham, S, 2016. A data science approach to identifying and quantifying causes of dilution at Cannington Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 491–500 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

The word "optimization", refers to the search of an economic optimum, or, more precisely, to the choice of technical parameters which will define the more profitable mining project, knowing the values of the economic parameters. In fact, there is no direct way to perform this optimization, because the extremely large number of technical factors involved, from the type of working and its selectivity to the characteristics of the mill and its flexibility, makes it impossible to make a comprehensive survey of all possible projects. Beside, it would be meaningless to engage in such a task as the deposits themselves are not really known, but only estimated, with sometimes a high level of imprecision. Not to mention the numerical instability which would affect such a computation! In addition, the "best" project is not necessarily the one which strictly maximizes a given profit formula. There also exist human factors which have to be complied with, when choosing the cutoff grades for instance. Finally, there are other non-numerical factors which interfere with the choice between several projects: the shape of the bottom of a pit of the layout of the access road for instance.

Jan 1, 1986

By M I. Pownceby, C M. MacRae, A Torpy

Electron probe microanalysis (EPMA) and quantitative X-ray diffraction (QXRD) techniques are capable of providing high-quality quantitative information regarding the phase mineralogy and distribution of alumina within iron ore samples. The techniques, however, use different methodologies in determining the mineralogical information (ie structural versus chemical), which introduces some limitations. In this study, EPMA was used to identify and quantify the deportment of alumina within mineral phases in iron ore samples (-1 mm crushed) sourced from different suppliers. Results were directly compared with quantitative mineralogical data derived from QXRD to provide an evaluation of the relative merits of both techniques. The four ores studied contained alumina either in the form of gibbsite, aluminosilicates (eg kaolinite), or associated with goethite.For minor phases, gibbsite and kaolinite, the abundance trends measured via QXRD were generally reflected in the EPMA data. Agreement was less satisfactory for the more abundant goethite phase (both low- and high-Al forms). The discrepancy may be the result of sampling issues arising from textural features such as grain size, and also a systematic overestimate in the amount of Al-rich goethite when hematite and Al-bearing phases are finely intermixed and the EPMA step size is coarse. A second difference in the EPMA results compared to the QXRD data was in regard to quantification of low-Al and high-Al goethite phases. The sensitivity of the chemical-based EPMA was better for distinguishing between high- and low-Al goethite although the results remain overprinted by potential errors introduced via sampling.Care should be taken when directly comparing results from each method, although in general the data should be considered complementary, as each approach provides slightly different results and interpretations regarding the overall mineralogy.CITATION:Pownceby, M I, MacRae, C M and Torpy, A, 2017. A comparison of X-ray and electron-based analysis techniques for characterising the mineralogy and alumina distribution in iron ores, in Proceedings Iron Ore 2017, pp 593–598 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The Australian Constitution specifies certain powers of the Commonwealth Government to be used in its capacity as the national government. Certain of these broad powers result in the Com- monwealth having a facility to play an important part in the development of the mining industry. The State Governments, however, by virtue of their wide powers to regulate matters within the boundaries of a particular State, are more directly involved in the day to day administration and standards of activities of mining operations. In this respect the Common- wealth has something of a dual role because of its "State-like" responsibilities for the mainland Terri- tories. The components of the role that the Common- wealth Government discharges in relation to the mining industry are qualified to varying extents at particular times by the political persuasion of the Government. In absolute terms the components are as follows. 1. Economic management. The Commonwealth's fiscal and monetary policies have an important effect on industry as well as on State finances. In particular, the taxation regime employed by the Commonwealth Government is of direct importance to economic decision-makers in the mining industry. 2. International matters. International trade and commodity matters are, more and more, becoming an everyday part of the conduct of a nation's foreign affairs. 3. Exports. The Commonwealth Government, via the constitutional powers over overseas trade, have exercised varying degrees of control over mineral exports to achieve particular objectives. 4. Foreign capital and investment. Australia in general, and the mining industry in particular, is and will continue to be a net importer of capital. There appears to be bipartisan political agreement in Australia that foreign investment policy must be enunciated to ensure that investors. are in no doubt that Australia welcomes beneficial investment and technology from overseas. 5. Environment and Aborigines. Governments, both Commonwealth and State, have in recent years become more involved in these areas in response to their interpretations of community aspirations. 6. Energy. Access to assured supplies of energy is now viewed, by Governments worldwide, as a desirable asset to ensure the well-being of a nation's people and industries.

Jan 1, 1978

By A F. Wilson

The use of stable isotopic measurements as a technique for elucidating the origin and history of the water in hydrothermal fluids is relatively new. Recent studies have emphasised the importance of meteoric water in the formation of many hydrothermal ore deposits including many epithermal gold-base metal deposits which occur in faulted volcanic terrane. Other vein-type gold ores are believed to have formed from fluids of magmatic or metamorphic origin and exhibit characteristic d180 values. These values also give information regarding temperatures and the degree of equilibrium. Preliminary oxygen data for some important gold deposits of eastern Australia are evaluated in the context of styles of mineralisation.

Jan 1, 1980

By M J. Kongas, K M. Saloheimo

This paper presents the art of on-stream particle size and elemental analysis used at iron ore concentrators, followed by the results and experiences from several sites.Online particle size analysis is rather common at medium- to large-sized concentrators. Online X-ray fluorescence (XRF) elemental analysis, however, is only used in some iron ore concentrators, while it is a routine practice in base metal concentrator plants. Online XRF analysis is applicable for process monitoring and control down to four to five per cent silica by measuring Fe assays accurately. With lower silica content, direct measurement of silica and other light elements is required. Some light element analysers that are based on the prompt gamma neutron activation analysis (PGNAA) method have been developed, but they have not performed up to expectations with slurry analysis. Other methods have been tried though these have not been used beyond prototype installations. Operating online light element slurry analyser installations are not common in iron ore applications.There is an economic incentive to mine lower and variable grade iron ore resources, which require concentration and removal of several impurities to produce high-quality concentrates for pellet production. Monitoring such operations by on-stream analysis has significant economic benefits, and there is a need to develop a dependable slurry online analyser for Si, Al, Mg and other light elements. The latest developments in slurry on-stream light element analysis are described.CITATION:Kongas, M J and Saloheimo, K M, 2013. Online slurry analysis for process control and monitoring at iron ore concentrators, in Proceedings Iron Ore 2013 , pp 303-308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

The Effect of High Power Nanosecond Electromagnetic Pulses on Selectivity of Pyrite from Arsenopyrite

Sep 13, 2010

Lower Miocene Maryville Coal Measures at Waitewhena Coalfield, in the Taranaki coal region, include seams of sub-bituminous coal up to 4 m thick. During coalfield exploration Fletcher Challenge Ltd drilled ten cored holes, all of which encountered at least one seam. Coal quality is variable. Ash ranges from six to 12 per cent and sulphur from 0.5 to three per cent. A basal seam, overlying the Lower Mokau Sandstone, appears to extend throughout the area under investigation. A rider seam, of variable thickness, closely overlies the main seam in most drillholes. The rider converges with the main seam to the north and vertical trends in coal properties suggest that the seams are united in some locations. A less extensive seam sometimes occurs at the top of the coal measures beneath the Upper Mokau Sandstone. The lithostratigraphy of the intervening coal measures is complex, and coexistence of fluviodeltaic, lagoonal/lacustrine, and marine depositional environments is provisionally inferred. Lateral variations in coal properties (clastic derived ash, volatile matter, inertinite, hydrogen), thickness of the sedimentary parting between the basal seam and rider, texture of the coal measure sediments, and distribution of the upper seam all indicate persistence of a relatively low lying northeast-trending zone which may have been structurally controlled. Available data indicate that coal measure accumulation was terminated by marine transgression from north to south.

Jan 1, 1987

COMPRESSED air is held in high esteem by the mining engineer as a medium for the transmission of power. The transmission, however, is accompanied by a high percentage of loss. Of the total work done by the steam cylinder'in compressing the air inthe air cylinder, less than 50% is ultimately utilized by the machines underground. These losses are due to its essential and inherent properties as a gas. One of the sources of loss is that due to transmission through the pipes which distribute the air from the receiver to the various places where it is used. As the capacity and economic design of air-compressing plant are influenced by this source of loss, it may be of interest to give an outline of how estimates may readily be made'in practice of thediameter of pipes, quantity of air discharged, and the drop in pressure occasioned.In hydraulics we have a general formula given M Rankine's "Civil Engineering" :It was suggested, the writer believes, in the first instance by D'Arcy, that this formula could be made to apply to an elastic...

Jan 1, 1918

By G P. W Suyantara, Y Tanaka, T Hirajima, Y Aoki, K Sasaki, H Miki

The effect of sodium sulfite (Na2SO3) on the flotation behaviour of bornite and tennantite is reported in this work. Flotation tests were performed using pure minerals of bornite and tennantite under various concentrations of sodium sulfite at pH 9. The flotation results indicated that sodium sulfite exhibited a depressing effect on the floatability of bornite in the presence of 0.1 mM PAX. However, tennantite remained floatable after the addition of sodium sulfite in the presence of 0.1 mM PAX. The flotation tests using mixed bornite and tennantite confirmed the flotation results of single minerals. Surface characterisation using X-ray photoelectron spectroscopy (XPS) was performed to explain the flotation results. A mechanism is proposed based on the XPS analysis results.

Aug 24, 2022

By Neville Rockhouse

This paper examines the interrelationship of conducting full risk assessments in the context of the coal mining industry and under the framework of the Health's Safety in Employment Act 1992. In the context of Occupational Health's Safety, Risk Management is a holistic management process that can be used by individuals working in all organisations and from all industries. The Australian New Zealand Standard 4360: 2004 defines a Risk as being; The chance of something happening that will have an impact on objectives. This definition is followed by several notes that include: a risk is often specified in terms of an event or circumstance and the consequences that may flow from it, risk is measured in terms of a combination of the consequences of an event and their likelihood, and risk may have a positive or negative impact. For the purposes of this paper, the above definition will be adopted. This paper examines the newly expanded approach of the fully documented risk management process in the New Zealand coal mining industry. This is done in the context of the coal mining regulations but more importantly by using the framework of the Health & Safety in Employment Act 1992. This legislation under Section 6 requires all employers to, Take all Practicable Steps to prevent harm coming to employees while at work and to others who might be at or in the vicinity of a workplace. When the term 'all practicable steps' is studied, one can clearly see that such steps should be the same steps taken that a prudent and reasonable person would have taken given the same type of circumstance. Due to the fact that in New Zealand parliament made statutes is administered by a Government Department, means that their breaches will be heard before a judge in the District Court. Under the Westminster System of Justice, a basic dictum of that court in matters relating the occupational health and safety is that a breach needs to be satisfied to a specific standard. That standard is, 'Beyond a reasonable Doubt'. One of the primary benefits of adopting a proactive approach to risk management is that if the industry were to adopt similar approaches, then this mythology could be seen as an industry standard. As such, the approach carries the same status in a court of law, as that of an Approved Code of Practice.

Jan 1, 2007

SPOT imagery acquired in May 1986 of the areas that include the Dugald River lead-zinc lode, northwest Queensland, Australia and the Ngwenalekau copper deposit, Botswana has been evaluated and compared with LANDSAT MSS imagery of the same areas. The data have been processed using band combinations, band ratioing, principal components analysis and classificatory techniques and the outputs compared with those of geobotanical, geochemical and biogeochemical data as well as geological information. For both study areas the image processing techniques cited have successfully distinguished discrete vegetation associations related to discrete surficial and bedrock geological units; and, notwithstanding the sharp contrasts between the nature of the geobotanical anomalies that in both areas occur over mineralised bedrock in Proterozoic sedimentary sequences, they have successfully identified the areas of anomalous vegetation over the mineral deposits. Greater vegetational and geological detail is revealed than on outputs generated from LANDSAT MSS data [see Cole, 1977, 1982(a) and (b)]. The additional information yielded by SPOT imagery compared with LANDSAT MSS imagery results from its greater spatial resolution - 20 metres as against 79 metres - and from ti fact that the three SPOT MSS spectral bands - 0.50 0.59um, 0.615-0.68um and 0.79-0.89um - respectivelc cover those sections of the electro-magnetic spectrum in which leaf pigments, notably chlorophyll, absorption for photosynthesis and leaf cell structure strongly influence reflectance. This accords opportunities for the detection of reflectance aberrations caused by stress due to drought and/or metal toxicity as well as for the identification of anomalous vegetation communities of moderate sizr These cannot be accurately discriminated on LANDSA I MSS imagery on which only very large geobotanical anomalies like that over the Lady Annie phosphate deposit in northwest Queensland [Cole, 1977, 1984; Cole and Owen-Jones, 19771 can be detected.

Jan 1, 1988

In presenting the paper, Mr. Davey quoted subsequent work which yielded k, at miscibility gap composition, of about 50.We can confirm the authors' findings for k j 300 for nearly pure tin to k 2 about 50 (average 47) from our own experience and from repeat experiments on materials described by the authors, at 1150°C.During laboratory-scale trials we also found confirmation of the authors' view that it is more difficult to reach equilibrium from the high-iron (in slag) side than from the low-iron (high-tin) side. Working from the high-iron side tends to yield results that point to a high k, leading to optimistic values of iron/tin ratio in final slags. In practice the smelting of a tin concentrate, unless it is exceptionally low in tin and high in iron, must yield initially a tin-rich slag and therefore equilibrium can only be reached from the "tinny" side.

Jan 1, 1967

By P Joyce, D R. Cooke

The Dinkidi Cu-Au porphyry deposit is situated in the Caraballo Range of North Luzon, Philippines. Although comparatively small, Dinkidi has unusually high gold grades with drilling by Climax-Arimco Mining Corporation delineating a 110 Mt orebody at 1.2 g/t gold and 0.5 per cent copper. The magmatic-hydrothermal evolution of Dinkidi records a distinctive switch in mineralisation from an early orthoclase-dominated Au-rich assemblage, typical of alkaline porphyry systems, to a later quartz stockwork Au-Cu rich assemblage typical of most calc-alkaline to shoshonitic porphyry systems. The early orthoclase-dominated stage is associated with the intrusion and crystallisation of a variably-textured clinopyroxene-syenite dyke that contains high-grade (5 - 20 g/t) gold mineralisation. We consider this dyke to be a Cu-Au porphyry analogue to the pegmatites found in granitic systems. Dinkidi is hosted within the Early Miocene Didipio Igneous Complex. This alkaline igneous complex is comprised of early unmineralised gabbros (pyroxene-plagioclase cumulates), clinopyroxenites (pyroxene cummulates), diorites and monzodiorites that have been intruded by a large, weakly mineralised monzonite pluton. The Dinkidi deposit is located at the southern margin of the monzonite pluton. Mineralisation is hosted within a composite monzonite stock. Within the stock, an 800 metres by ~200 metres (plan section) elongate monzonite stock (Tunja Monzonite) predates and hosts the bulk of the Au-Cu mineralisation. This has been intruded by the thin (10 to 30 m wide), highly mineralised variably-textured magnetite- and clinopyroxene- phyric syenite pegmatite (the Balut Dyke). The youngest phases of the composite stock are leucocratic quartz-monzonite porphyry (Quan Porphyry) that grades texturally, in its core, into a post-mineralisation crystal-crowded quartz-syenite (Bufu Felsite). The late-stage Bufu Felsite is inferred to be the source of much of the Cu-Au mineralisation. The Didipio Igneous Complex has intruded a sequence of Late Oligocene alkaline andesitic lavas and volcaniclastics and overlying potassic dacitic lavas. Whole rock geochemical analyses indicate that the intrusions and the potassic dacite lavas in the surrounding region are co-magmatic. Five main stages of hydrothermal activity are recorded at Dinkidi. An unmineralised K-silicate (biotite-magnetite) alteration assemblage formed during the intrusion of the Tunja Monzonite stock. The diorites surrounding the stock display intense selectively pervasive biotite and magnetite alteration and are cut by an extensive network of orthoclase veins and monzonite dykes. The orthoclase-dominated assemblages of Stage Two carry substantial high-grade Au mineralisation and are associated with the intrusion of the Balut Dyke. The emplacement of this unusual dyke is associated with emplacement of pegmatitic clinopyroxene-orthoclase-magnetite¦sulphide dykes, localised orthoclase flooding along the margins of the dyke, and subsequent emplacement of an extensive orthoclase-actinolite-bornite¦chalcopyrite-fluorite stock-work, and development of widespread selectively pervasive actinolite alteration. The main stage of Au-Cu mineralisation at Dinkidi is intimately associated with the intrusion and initial crystallisation of the leuco-monzonite porphyry (Quan Porphyry) and emplacement of a quartz stockwork followed by carbonate-sulphide deposition and intense vein-related sericite and carbonate alteration assemblages. The quartz stockwork formed synchronous with the deposition of the æBugoy QuartzoliteÆ, a very coarse grained mosaic of quartz-orthoclase-perthite along the walls and top of the crystallising intrusion. Stage 3 was terminated by crystallisation of the distinctively vuggy Bufu quartz-syenite phase in the core of the intrusive, with associated antiperthite veins, and the subsequent explosive brecciation of the roof of the intrusion, forming a quartz-fragment breccia from the Bugoy Quartzolite. Retrograde metasomatism during Stage Four was intimately associated with the emplacement of extensive, late-stage carbonate, silica and zeolite veins and widespread selectively pervasive carbonate alteration. The last hydrothermal stage at Dinkidi, Stage 5, is comprised of strong selectively pervasive clay alteration and is associated with fault-related brecciation of the Dinkidi stock.

Jan 1, 1999

While the new Minister of Economic Development sends his apologies at being unable to speak at this Conference, I am delighted to present on his behalf. The Ministry of Economic Development is not only responsible for managing the Crown mineral estate, but also for developing initiatives and policies to promote regional economic development and for managing the GovernmentÆs broader economic development strategy. IÆd like to talk to you today about the critical links that need to exist between these three areas.   I am going to start with a question for all of you. What do these towns have in common? +        Waiuku, +        Thames, +        New Plymouth, +        Nelson, +        Greymouth, +        Arrowtown, +        Reefton, +        Palmerston, and +        Dunedin.   The answer is minerals. These towns were nearly all founded on the back of minerals and mining. In the case of Greymouth it was gold that brought the people to the mouth of the Grey River and it is coal that sustains the town.   In 1870 the town of Shortland had 20 000 people, 90 hotels and was twice the size of Auckland. We now know Shortland as Thames, and of course Auckland is considerably larger. One wonders whether the good folk of Shortland suffered from ætraffic jamsÆ with 90 pubs to navigate between. Gold mining in the Aorere River near Collingwood led early entrepreneurs to develop the land surrounding Nelson as a food basket to sustain the mining population. Nelson is still thriving on this legacy today. The town of Palmerston was founded in 1862 as a stopping point for gold miners heading into central Otago. The gold rush made Dunedin New ZealandÆs first highly industrialised city. Reefton on the West Coast was the first town in New Zealand to have electric lights and in the recent past we were wondering whoÆd be left to turn them off. New Plymouth, and Waiuku are still known as energy and mining centres.   By contrast once thriving towns like Capleston, Canvastown and Blackball are just names on a map now, and at the extreme you have places like Waiuta which has been reclaimed by the West Coast forest. Queenstown was built off the back of the gold rush, but by 1900 with the gold gone, only 190 people lived there yet Queenstown has managed to rebuild itself thanks to some other stunning natural assets. These examples help illustrate three key points that I am sure will each be extensively linked with our minerals and mining industries. First, NZÆs development and that of its regions has been, and continues to be, inextricably linked with our minerals and mining industries.   Second, things change. Sectors, regions and countries must continually adapt and improve if the are to avoid the fate of the Waiutas of this world. And third, the development challenges faced by NZ and its mining industry in the 21st century are vastly more complex than in the past. Governments and industry alike must balance and respond to a range of domestic and international environmental, cultural, economic and other interests and considerations. If you thought of your industry as æjust digging holes in the groundÆ then you may as well simply stick your head in one!

Jan 1, 2005

Coal production from Coal & Allied's Hunter Valley No 1 open cut is presently hauled 10 km by road to washing and train loading facilities at Liddell. This road haul, using bottom dump trucks on a bitumen sealed road, presents some unique earthmover tyre problems. Sound tyre management has controlled one potentially serious problem, that of heat damage, implicit with such a long haul. Tread abrasion or wear is therefore the limiting tyre performance factor. Study of abrasion mechanisms and interpretation of abrasion patterns has facilitated an understanding of the wear processes involved. This understand- ing has highlighted the importance of front tyre wheel alignment. The development of irregular wear is shown to be related to the mildness of the abrasion and methods of remving irregular wear are presented. In conclusion haulage by large off highway trucks on long sealed haul roads has been eooncoically and technically successful at Hunter Valley No 1. INTRODUCTION Hunter Valley No 1 (HVl) is a major open cut coal mine, owned and operated by Coal & Allied Operations Ltd, and located in the Hunter Valley of New South Wales. Present

Jan 1, 1982