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By J L. Mauk

The Martha epithermal Au-Ag deposit contains multiple generations of quartz veins with a range of textures. We examined: +        vein textures, +        crosscutting vein relationships, and +        the paragenetic sequence within the pit walls as well as a wide range of hand specimens. Samples include host rock, breccia, and veins, but these groups are not distinct; instead, they form a continuum.   Veins at Martha mine show a wide range of textures on a local scale; these textures also change significantly over both the lateral and vertical extent of the pit. Common textures include crustiform bands, comb quartz, colloform bands, platy quartz, massive quartz, drusy quartz, sedimentary textures and brecciation.   Vein grades relate to textures. Many textures, including crustiform, platy, cherty, and sedimentary textures display predominantly low grades, but some textures are linked with high grades, such as ginguro, massive and comb quartz where they are associated with visible base metal sulphides and/or electrum. Host rocks and most breccias are low grade, as most samples contain <2 ppm Au.

Jan 1, 2006

By A Bax, G Wardell-Johnson, A Giblett, W Staunton

This paper presents a number of key considerations for process development testwork as a reliable basis for the inclusion of gravity separation in gold recovery flowsheets. Operating data, experiences and numerous case studies are also discussed in support of identifying best practice principles for gravity circuit design.CITATION:Giblett, A, Bax, A, Wardell-Johnson, G and Staunton, W, 2013. A review of best practice in gravity circuit design and operation, in Proceedings MetPlant 2013 , pp 272-284 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

During the latter part of 1937 consideration was given to the construction of a; local smelting plant for producing blister copper. Previously copper concentrates had been shipped to the United States of America. The proposition had the advantages of a saving in cost of realization, quicker financial return and reduced dependence on overseas shipping.The smelter was designed by the existing staff, who had difficulty in obtaining data on small plants, particularly on the reverberatory furnace. Construction was started in March, 1938, and the reverberatory was blown in on January 16th, 1939. One roaster had been operating for several weeks prior to this date.While results and operating technique on this new departure in small-scale smelting are barely beyond the experimental stage, it is felt that the experience gained to this time should be recorded to help fill the obvious gap in published information covering plants of this type.At present there are three copper smelters operating in Australia; the other two plants are equipped with blast furnaces.LOCATIONThe new smelter is situated in a position convenient to the concentrator and to the power plant. The site is traversed on two sides by a brick flue, from an old smelter plant, which connects with a 250-ft. stack. This stack and portion of the old flue are used in connection with the...

Jan 1, 1939

By Tumilty JA, Schmidt CG

Sulphide ion is a powerful poison in gold cyanidation, however, the detrimental effect is less severe in plant practice. This is thought to be due to the presence of depassivating elements in the ore, mainly lead. Trace amounts of lead can counteract the poisonous effect of considerable amounts of sulphide. The reaction is instantaneous and is likely to be a direct involvement in the electrochemical surface reaction. Lead addition cannot be regarded as an all-round cure when experiencing poor leach efficiencies. A possible beneficial effect depends on the mineralogy of the ore and has to be determined individually for every material.

Jan 1, 1989

By Giannini M

Of the optimization techniques proposed in determining the optimum open pit limits, dynamic programming and graph theory have proved most successful. However, publications on these two methods lack a certain amount of rigour and clarity in exposition. Certain ideas in the methods have been clarified and additional features introduced in order to make them more sensitive to practical applications. A case study in the form of an application of these ideas on data from a producing mine is presented and discussed.

Jan 1, 1986

By T Do, J Siliezar, M Larson

With the expansion of magnetite projects in Australia has come the opportunity to take advantage of newer technologies that were not necessarily available when the magnetite industries of North America and Europe were maturing. One of these technologies is the IsaMill, originally developed for the economic treatment of ultra-fine grind (UFG) duties of Mount Isa Mines. As understanding of the IsaMill has increased, so too has the ability to process coarser feeds while maintaining the same energy efficiency advantage and tight product size distribution that originally made the IsaMill so attractive. In the case of magnetite the hard non-elastic ceramic grinding media is ideally suited to the grinding duty when compared to steel grinding media. The centripetal separator and naturally steep product size distribution curve provide a mill discharge that maximises the critical concentrate grade. This paper analyses the effect of the IsaMill grinding technology on the full-scale Ernest Henry Mine (EHM) magnetite operation along with pilot and lab scale demonstrations of optimisation. Issues encountered and the solutions to maximise the mill throughput and quality are examined in an effort to promote better understanding across the industry. CITATION:Larson, M, Do, T and Siliezar, J, 2013. Enhancing magnetite returns - the benefits of IsaMilling, in Proceedings Iron Ore 2013 , pp 411-416 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By N H. Jansen, H L. Bridgwater

Field portable X-ray fluorescence (XRF) and near infrared (NIR) instruments are proven technologies in the minerals industry. The in-field results of these instruments can add value early in the project life, leading to cost-effective decision-making compared to their equivalent laboratory based techniques. However, in order to add value to a project, it is crucial that the instruments are employed correctly.Orientation studies should be carried out prior to initiating a sampling program to achieve the highest level of quality assurance and control for the results. Hence, an appropriate sampling workflow begins with considering what outcomes are required, including level of precision, accuracy, reliability for elements and minerals of interest, and sampling errors. The workflows proposed include soil sampling and reverse circulation and diamond drilling sampling techniques, and laboratory based techniques. They are practical and flexible workflows using available portable XRF and NIR technologies that can be applied to current sampling and drilling methods.The combined technologies have the ability to create large, integrated geochemical and mineralogical data sets that can provide cost savings for every stage of the mining chain from exploration to prefeasibility, mineral processing and environmental remediation.CITATION:Jansen, N H and Bridgwater, H L, 2017. Proposed workflows for portable X-ray fluorescence and near infrared instruments for soil and drill hole sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 219–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By P E. H Gregg, R B. Stewart

Reclamation field trials commenced in 1985, two years before the granting of the Mining Licence. The level of pasture production on varying soil depths (0 cm, 5 cm, 15 cm and 25 cm) overlying both tailings and oxidised waste overburden was assessed.   After seven years, the rate of increase of N, C, P and S, losses of Sand P and pH changes were investigated on the plots where grass seed was sown into bare tailings. It was determined that on these plots it would take approximately 24 years to reach the original carbon and nitrogen levels at the mine site. Further tailings trials have been initiated to investigate alternative land use options for the tailings dam. Growth increases of 73% occurred in native species growing directly in tailings, and growth increases of 78% occurred in tailings amended with compost over the first six months. Pasture trials on tailings with and without a compost amendment have also been initiated. Research has commenced to investigate the restoration options for acid producing pit slopes. The early field trials have been put into practice with the restoration of oxidised waste on the tailings embankment. This is progressive with approximately 16 ha restored to productive pasture at present. Yields compare well with those of the most versatile and productive soils types investigated in baseline studies of the area before the tailings dam was constructed.

Jan 1, 1995

Present roof bolting practices in the collieries of Australian Iron and Steel Pty. Ltd. are outlined. Roof support has been improved since introducing roof bolts and it is hoped to increase the reliability of the bolts still further.Expansion-shell, and split and wedge roof bolts five to eight feet long are placed by "Atlas Falcon" and "Fletcher" roof bolters. Both anchorage and tightening have presented some problems.Good panel supervision is required if systematic roof bolting is to be properly co-ordinated with coal production without unnecessary delay to either. Successful roof bolting can only be the product of conscientious men and supervisors who are all convinced of its value. A rigid operational code should be established early and maintained.INTRODUCTIONRoof bolting is a method of support which is permanent and reduces or eliminates the need for other support; The method was pioneered in America and was first experimentally investigated in Australian collieries at Elrington in 1949 (McKensey, 1953). Pneumatic installation methods were employed. Subsequently, a method of using standard hand-held electric coal drills was developed at John Darling Colliery (Horseman, 1954). Pneumatic roof bolting equipment was first operated in the collieries of Australian Ironand Steel Pty. Ltd (A.I. &. S.) in 1951. Since then various hydraulically operated mobile machines have been installed in Australian collieries and these, together with improved pneumatic equipment, form the two present basic methods of placing ,roof bolts. Roof bolt anchorage is achieved by either split and wedge or expansion-shell bolts.The two broad types of roof bolting are 1. consolidation of strata, and 2. suspension support.

Jan 1, 1961

By Cadman S. J

( The central part of the Gippsland Basin is surrounded by existing major Petroleum accumulations and although six exploration wells have been drilled in the area, none are significant petroleum discoveries. Post drilling analyses indicate that the wells were drilled off structure due to the presence of high-velocity Miocene channels. These channels contain carbonates of significantly higher interval velocity than the surrounding sediments. Problems with seismic interpretation were thus encountered in the development of prospects in the central part of the Gippsland Basin as part of a BMR prospectivity study. The seismic interpretation problems associated with the Miocene channels are two-way time pull-ups at the underlying top of Latrobe Group and deeper levels on the seismic sections. Interpreted seismic sections passing through some of the exploration wells and the Miocene channels are presented to illustrate the configurations of these channels and the pullup effect associated with them. Two different methods of depth conversion were applied, one for the area below the high velocity channels and the other for the area away from the channel. The application of these two methods of depth conversion were found to be reasonably successful in correcting for the pull-ups caused by the high velocity Miocene channels. Mapping of the events near the top of Latrobe Group and near Base Lower L balmei seismic horizons has led to the identification of several potential structural closures. Further exploration efforts are necessary in this area to test these closures.

Jan 1, 1992

By Rose W. J

Geophysical prospecting was first recognized in Australia as an important aid to mining enterprises in 1927, when, on the suggestion of Sir Herbert Gepp, the "Imperial Geophysical Experimental Survey" was organized. The function of this survey was to carry out investigations on the applicability and efficacy of the most important geophysical methods under Australian conditions. The survey was formed under the joint auspices of the British Empire Marketing Board and Australian Commonwealth Government, and the investigations were carried out in Australia under the leadership of Mr. A. Broughton Edge, B.Sc., A.R.S.M., F.G.S., M.Inst.M.M., during the years 1928 and 1929. A description of the work performed, the apparatus used, the principles of the methods, and the results and conclusions of the survey are included in a report published by the Cambridge University Press in 1931.In 1932 Sir Herbert Gepp became interested in some gold mines in Eastern Victoria, in the Cassilis and Bethanga districts, and realizing that the lodes in these areas would be favorabIe for a geophysical examination, he arranged for a series of tests to be carried out. This work was performed by Mr. E. L. Blazey, B.E.E., a former member of the staff of the Imperial Geophysical Experimental, Survey, under the general direction of, and in consultation with, Mr. W. J. Rose, B.M.E.The work was commenced in October, 1932, at Cassilis, Vie., continued at Talgarno, Vie., .and concluded at...

Jan 1, 1933

By A B. Christie, R L. Brathwaite, A Swain

This study provides quantitative data on vein distributions within seven selected epithermal systems, four deposits hosted predominantly in rhyolitic rocks: Ohui, Wharekirauponga, Neavesville and Komata, and three major deposits mainly hosted in andesite: Martha Hill, Golden Cross and Karangahake. The technique of fractal analysis was used to help quantify vein distribution patterns. The fractal dimensions (D) obtained are related to the number of veins per metre, the degree of vein clustering, and vein thickness. An increase in any of these tends to increase the fractal dimension.   It is the relative relationship of these parameters that is important for the characterisation of vein distributions, and the comparison of different deposits. Within the same systems, the rhyolites are characterised by lower vein thickness and vein density, but have a higher degree of vein clustering compared to the andesites. Sections that are deeper and more centrally located within the epithermal system and/or close to major structures tend to have a greater degree of vein clustering, higher average vein thickness and density, and higher thickness to density ratios. This depth control is most pronounced in epithermal gold-silver systems because they have formed at shallow crustal levels where physico-chemical conditions change drastically both vertically and laterally. In addition to lithological and structural control at vein scale, deposit scale structure is of great importance in the deposition of economic mineralisation. Large open vein structures capable of sustaining high fluxes of hydrothermal fluid, favourable for the formation of large, high-grade gold deposits, are best developed in andesite sequences.

Jan 1, 1995

By D Matthews

With a brownfield project comes control integration challenges. The Khumani Iron Ore Mine’s second phase expansion posed a number of challenges as there was substantial brownfields work conducted. The fi rst phase was the compilation of the modifi ed process functional specifications for the project. The second phase was an audit on all of the operational sequences; this included a comparison between the SCADA sequences, sequential starts analysed from the historian data (with the potential for improvements made by the plant operators in manual start-ups) and what was proposed in the process functional specification. Differences, inclusions and missing equipment were highlighted. The third phase was the comparison of interlocking and control in the PLC with the updated process functional specification; this was done during the coding process. Running parallel to the three phases was the SCADA integration; tie-ins to the existing SCADA were conducted on maintenance days and shutdowns, in many instances with ‘dummy’ equipment to get the operational staff accustomed to the new interface. This paper details each of the phases, the success of this methodology as well as the pitfalls experienced.

Jul 11, 2011

Acoustic Emission Monitoring of Froth Flotation

Sep 13, 2010

Solid Energy New Zealand Limited has grown significantly since becoming a State Owned Enterprise in 1987. Exports, profit, turnover, output per employee are all trending upwards. The company has identified the management of Health and Safety as a key capability to sustain future growth, and to add value to the business. It has set a target of being the best practice in managing Health and Safety.   This paper examines the company's activities in the Health and Safety area, and how it sees that value can be added by preventing and containing losses through accidents involving people, property, process and the environment. Solid Energy is confident that a Planned approach to managing Health and Safety can achieve this. It will explore historical events, strategic changes, Health and Safety systems, Benchmarking, Performance Measures, initiatives, progress to date and challenges for the future.

Jan 1, 1997

By Kanau JL, Kilgour I

This paper describes the metallurgical processes at the 80 000tpd Ok Tedi Mining Limited concentrator, which treats copper- gold ore by single-stage crushing, SAG and ball milling and flotation to produce over 500 000tpa of concentrate. Plant and process developments, including installation of column cells, reduction of fluorine in concentrate, use of sulphidisation and process control improve- ments are also discussed.

Jan 1, 1991

The theme of the conference is "excellence", an epithet of special significance in tertiary education. It appears in the mission statements, goals and plans to achieve them of most, and quite possibly all, tertiary institutions in Australia. In the context of excellence, this paper examines the current statue of professional education in the principal mining industry related discipline of Mining Engineering. It furthermore, identifies and discusses a number of special problems in mining education that the tertiary sector has long endured. Some of these problems are becoming acute, and solutions will have to be found soon in order for the industry to be assured of the supply of well motivated and appropriately qualified young engineers and scientists necessary to achieve and maintain the excellent to which it aspires.

Jan 1, 1989

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.   There is a great need to improve science, natural science, education at all levels. All people must know how our planet works and that fluctuations, some inevitable, some controllable, are inevitable and that we must prepare for them. And it is clear that protecting the environment, eliminating pollution, preserving bio diversity is good economics. Ecology Economy cannot be separated.  

Jan 1, 1995

As in other countries, gold mining inNew Zealand has been cyclic in character. Looking at these cycles may provide insights as to what may occur in the future and that is the basis for this study.   New Zealand has experienced four gold mining cycles. The first began in 1857, peaked in 1866 and terminated in 1890. This cycle was characterised by alluvial gold mining by individuals and small groups. This is referred to as the Labour Led cycle. The second cycle began in 1890 and reached its peak in 1906 and terminated in 1929. This cycle was characterised by the use of dredges in alluvial gold mining and was also the peak of hard rock mining. This cycle is referred to as the Technology Led Cycle. The third cycle peaked in 1940. This cycle was far less significant than the previous cycles, arising out of the depression when the unemployed embarked on small scale alluvial mining. This overprinted the continuing decline that occurred after 1906. This cycle is here referred to as the Depression Overprint Cycle.   The fourth cycle began in 1984 when production began to climb rapidly from a very low base. The growth in production was spurred by rising gold prices in the early 1980s resulting in relatively low grade gold-bearing alluvial ground becoming economic. But in the 1990s, production from the new hardrock mines in Coromandel and Otago has overshadowed alluvial production. This cycle is here referred to as the Price Led cycle.   What are the future prospects for gold in New Zealand? Although there are many factors involved, this will be largely determined by two factors; firstly, continued access to prospective gold-bearing properties, and secondly, the price of gold. Based on these factors, three future industry scenarios have been developed. The first of these is industry collapse, in which access to prospective property is constrained and prices mayor may not weaken. The second is industry consolidation, in which the available ground is accumulated by a small number of large companies who can use economies of scale to weather price fluctuations. The third scenario is industry growth, in which access to prospective ground is constrained in environmentally sensitive areas but is otherwise relatively unconstrained. Efficient companies are allowed to work in a policy and economic framework that allows them to make a major contribution to the economy.   While the industry cannot control these critical factors, a good knowledge of the positive role gold mining could play in the future economy may provide a framework by which the access issue, in particular, may be addressed from a balanced perspective.

Jan 1, 1994

By P Lindsay, J B. Hughes

Underground and opencast coal mining has been ongoing since 1896 on the Stockton Plateau, West Coast, New Zealand. Acid Rock Drainage (ARD) from historic and current mine workings has had an adverse environmental impact on the surrounding aquatic environment. The two main catchments affected by ARD are those of the Mangatini and St Patrick streams. These catchments flow into the Lower Ngakawau River, which holds high amenity value for the local community. Water quality targets set by Solid Energy for 2010 in the Ngakawau River include increased pH and clarity and a decrease in certain dissolved metals.   At-source ARD minimisation options are the first stage in mitigating the effects of mining acid forming rocks and reducing acid loads in the Mangatini and St Patrick stream catchments. ARD minimisation techniques reduce the quantity of acidity generated and thus reduces the treatment required. Treatment will be required for many years at Stockton due to current and historical acid formation. This paper looks at the treatment options that Solid Energy has been investigating including limestone leach beds, engineered wetlands, oxic limestone drains, and limestone dosing of catchment drainage. Particular focus is given to fine limestone dosing of the Mangatini stream and subsequent water quality improvements.

Jan 1, 2007