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For the past 3 years Waihi as a community has been actively engaged in consultation about its future with regard to the environmental, cultural, economic and social viability. This has been made possible through the implementation of the Waihi Community Vision (WCV) process which bought together a diverse range of people and interests.   Through their collaboration and collective energies, they produced a montage of possibilities for the future of Waihi, known as the 2020 Vision. A proceeding evaluation process was adopted by the group to enable the myriad of projects to be assessed and prioritised in terms of the communityÆs social, economic, cultural, environmental and spiritual values.   From this came the desire to be involved in the implementation of these ideas and create an organisation that could facilitate the successful manifestation of the 2020 Vision and other suitable projects.   The Vision Waihi Trust (VWT) was formed in February 2006 and is intended to be a tool through which the community can address issues about its future sustainability. They will work collaboratively with community groups, Hauraki District Council and Newmont Waihi Gold to develop and implement innovative and practical solutions. It should be acknowledged that such outcomes are subject to influence by both external and internal factors and it is important to consider this when looking at sustainability issues.   Waihi is now at a very interesting stage of its development and has the opportunity to proactively design and implement plans to determine its future rather than just let things evolve. A town with a strong sense of its roots and with a strong community identity may be a more attractive as a place live and work. There are additional business opportunities which may also be stimulated by a community that takes charge of its own destiny.   The process that has been worked through over the past three years gives a solid foundation on which to build and must be viewed as positive community development. Waihi certainly has a unique proposition to take to the marketplace, based on its rich gold mining heritage and current modern day mining operations. This requires investigation, refinement and implementation and Vision Waihi Trust looks forward to building to a vibrant and prosperous Waihi in the years to come.

Jan 1, 2006

By J Mauk, J Rowland, S Rabone

Most epithermal Au-Ag deposits in the Hauraki Goldfield are hosted in late Miocene andesites. Broken Hills is an exception, being one of the few economic deposits hosted in rhyolite. Investigation of Broken Hills provides the opportunity to collate structural data that may be compared with that collected from andesite-hosted deposits in order to evaluate the importance of rock type on vein development. The rhyolite host rock at Broken Hills is strongly flow-banded, but this anisotropy does not appear to affect the orientation of mineralised structures. There is a range of structures at Broken Hills: veins, faults, fractures, and large breccia pipes. Veins generally strike north-south, with localised changes in strike and thickness. Slip vectors determined from striations indicate near pure dipslip on the main lode, indicating an extensional tectonic setting. The orientations of vein deflections are parallel to slip vectors. This correlation is common in modern extensional fault arrays where fault growth and linkage produces subvertical deflections in fault orientation (eg TVZ). There are three main types of breccias: 1. Primary breccias related to rhyolite emplacement. 2. Jigsaw type secondary breccias that are that developed during the life of the hydrothermal system. 3. Breccia pipes. Broken Hills was a dynamic epithermal mineralising system.

Jan 1, 2003

A good deal of experimental work has been done from time to time on the application of compressed air to the elevation of wet pulp. On account of the flat nature of most of our mill sites elevation of the pulp has to be provided for, and the various methods in vogue show considerable loss of time, in the replaceing of wearing parts. During the last two years the writer has carried out a great many experiments with a view of devising an elevator that will give continuous work with a minimum of wear.The results do not show a high efficiency for the power employed, but the lift is continuous in operation, very cheaply installed, and possesses no wearing parts. The lift was tried working in a bore hole of 8 in. diameter, but in many cases it is more convenient to sink a small well for the purpose. The result to date showed that the most efficiency was obtained when the depth of the wellwas not less than the height of the lift required. The pressure of air required in pounds per square inch was (approximately) half the number of feet to be lifted.In the majority of cases the lift required varied between 20 ft. and 50 ft. and the air pressure required between 10 lbs. and 25 lhs. per square inch. In most existing installations the air compressors in use were delivering air to the receivers at about four times that pressure, and when air so compressed was expanded to perform its work at a reduced pressure, it was apparent that the power exerted in origInally compressing the air above the working pressure required at the lift was absolutely lost.

Jan 1, 1901

By H Susanto, N Belluz, D Flint, A Edw

The Deep Ore Zone (DOZ) is a block cave mining operation exploiting a diluted reserve of 131 million tonnes grading 1.06 per cent copper and 0.81 g/t gold in the lower portion of the Ertsberg East Skarn System (EESS). The EESS is a calcium-magnesium silicate skarn containing in excess of 250 million tonnes of copper-gold ore, located in the Ertsberg Mining District on the crest of the Jawawijaya mountain range in the highlands of Irian Jaya, Indonesia. The EESS was discovered in 1968 where it cropped out at an elevation of 4050 metres above sea level. The Ertsberg Mining District is underlain by siliclastic carbonate and siltstone formations of Jurassic to Tertiary age. The sediments have been folded and are cut by major bedding subparallel and crosscutting structures. Intrusion of a series of igneous bodies post-dates folding and faulting. These I-type intrusions are the source for the copper-gold mineralisation found in the Ertsberg Mining District. The EESS is hosted by carbonates of the Tertiary Waripi and Faumai Formations that have been altered to calcium-magnesium silicate skarn and is situated on the southern limb of a northwest-trending syncline. The EESS is an essentially vertical tabular body with a vertical extent of at least 1200 metres and a lateral extent of up to 1000 metres. The width of the EESS averages 200 metres and locally is in excess of 300 metres. The northeast (hangingwall) contact of the EESS is a skarn reaction front in sudden contact with barren marbles. This contact coincides with a zone of localised faulting and brecciation. The EESS is bounded to the southwest (footwall) by the Ertsberg Diorite, a 3.25 Ma old intrusive. The DOZ block cave operation extends from 3040 metres above sea level to a maximum of 3388 metres above sea level, has a length of 860 metres and a maximum width of 350 metres. The DOZ is a high temperature skarn with a prograde forsterite/diopside mineralogy whose protolith is the dolomitic Tertiary Waripi Formation. The principal retrograde alteration minerals include tremolite, actinolite, serpentine, talc and chlorite. Grade is highest where bornite occurs in large dense complex intergrowths with magnetite and anhydrite. Grade has been locally enhanced in the DOZ by a late-stage pyrite-chalcopyrite hydrothermal alteration event with associated brecciation. Ertsberg Diorite along the footwall of the skarn is also included in the reserve where it is mineralised endoskarn or has been mineralised by porphyrytic or late stage hydrothermal alteration. Formation of the EESS was initiated by contact metamorphism during the intrusion of the Ertsberg Diorite with later metasomatic alteration during both prograde and retrograde phases. The bulk of sulphide mineralisation formed late in the retrograde phase. The EESS is open along strike to the northwest and down-dip with on-going exploration of these areas. Current exploration is targeting both endoskarn and porphyry style alteration and mineralisation of the Ertsberg Diorite.

Jan 1, 1999

Reasons are given for the seemingly excessive public concern with taxation of the mineral industry. Optimality of mineral extraction is a concept that requires careful definition in terms of one or more objectives. Once defined, the impact of taxation upon optimal mineral extraction may be studied; findings from earlier work on this topic are presented for two basically different cases. In conclusion it is observed that the pursuit of optimality requires the availability of highly skilled engineers; in the event of a large-scale mineral development it is this resource that is probably scarcest of all.

Jan 1, 1983

Some Otago quartz veins display spectacular open-space filling textures indicative of shallow formation. Fluid inclusions in some such veins show that fluid immiscibility occured before or during mineral deposition. This immiscibility or 'boiling' occured at depths ranging from about 3 km to within as little as about 100 metres of the paleo-surface. Temperatures of mineralization range from 190 - 250¦C. Metals deposited in these veins include: Au(+Ag), Hg, Sb and As. Hydrothermal alteration is confined to minor silicifation of immediate wall-rock schist, less than about two metres from the veins. These veins have some similarities to classical epithermal systems elsewhere in the world, although wall-rock alteration is much less developed in Otago. From analogy to these classical epithermal systems, it is speculated that gold mineralisation may be found beneath Otago stibnite and cinnabar localities.

Jan 1, 1987

The West Coast region of the South Island is situated astride the Pacific û Australian plate boundary zone. The most significant component of this zone is the Alpine Fault. A variety of reconstructions of the pre-Alpine Fault plate tectonic configuration of the New Zealand continental area have been attempted over the past 25 years or so. Most of these have not been closely constrained by a regional compilation of field data related to the age and horizontal displacement history of the Alpine Fault. A model in which the Alpine Fault was initiated no earlier than the interval 18 - 16.5 Ma (B.P.) is proposed, a significantly younger age of inception than has been widely accepted as the onset of dextral displacement along the plate boundary through the South Island. A subsequent history of displacement is presented consistent with the West Coast basin stratigraphy. The alluvial gold content of some parts of the Miocene to Pleistocene conglomerate sequences is also discussed.

Jan 1, 1996

By M Nehring, E Topal

Nowadays mining projects are seeking new versions of evaluation that are based on the flexibility in the project. Real option valuation (ROV) is one of the modern evaluation methods that provides a tool to adapt and revise mining projects under uncertainty and future variable movements. Most evaluation approaches simply assume that some variables are fixed, such as production rate, variable cost, fixed cost and lifetime of project. The first section of this paper reviews a comprehensive study of ROV in mining projects. The paper then introduces a new model that solves problems where previous methods lacked. The new method endeavours to find maximum mining project value by adding total cost as a function of production rate into ROV. The second section has been applied to a new model on the Century zinc mine in north-west Queensland, thus illustrating the future overview of that mine. The new version of ROV gave a significant positive value for the Century Mine, when the closure and reopening options where available throughout the life of the mine. Consequently, the new method evaluates real options to add value to mining projects, maximising projectÆs value, estimating cost function, optimising production rates and offers opportunities in projects to amplify gains or to mitigate losses.

Jan 1, 2009

By M J. Kindley

The Golden Cross Gold Mine Project is now fully operational and into its second year of operation. Because of its location in the sensitive Coromandel Peninsula , strict water management and environmental requirements had to be met. This led to the development of new technologies for cyanide recovery and the adoption of advanced water management and water treatment systems. This paper discusses the water management and treatment system adopted for contaminated water at Golden Cross and provides data on the operational history to date.

Jan 1, 1993

By A Tinnelly

Land disturbed by alluvial gold mining should be restored to a capability or productivity as good as that which existed prior to disturbance.   Effective rehabilitation requires detailed planning prior to mining and must also be closely integrated with the mining operations.   The main constituents of a rehabilitation plan: description of existing site conditions, choice of final land use, establishment of final landform, water management and erosion control, soil reconstruction, revegetation and management of rehabilitated land are briefly described.

Jan 1, 1989

If the industry keeps doing what it has always done, it will continue to get what it has always got - rising operating costs. Why is this so? Generally grades being chased are becoming lower, stripping ratios becoming higher, ability to attract personnel to the industry becoming harder and/or more expensive, higher safety standards are being demanded and environmental governance is being enforced.   How then should the surface mining industry plan for the future whilst delivering on improved safety and the environment? In-pit crushing and conveying (IPCC) points the way, as a partial or complete substitute for trucks.   IPCC systems promise significant advantages over traditional truck and shovel operations, including improved safety, reduced operating costs, reduced dust and noise emissions, far greater efficiency in energy use (electric versus diesel motors predominantly and the ability to regenerate electricity back into the local grid for downhill situations), reduced carbon emissions (dependent on power generation source) and reduced water consumption. Despite these advantages, there is a general industry reluctance to migrate from truck and shovel operations. This reluctance stems from a familiarity with truck and shovel operations and a perceived concern that IPCC lacks flexibility which will negatively impact on the mining operation.   In studies conducted since 2007 (with the new modular builds) comparing IPCC with truck-optimised pit designs, IPCC has delivered up to USD$0.82 per tonne moved less than an equivalent truck operation. In addition, IPCC is easily automated from a central control room (local or remote) - something that trucks have yet to commercially achieve.   IPCC is a proven process that, with a fresh mindset, can make a significant improvement to mining operations - its safety, the impact on the environment and its costs. It maybe of interest to note that there is over 200 IPCC installations worldwide today.   This paper and presentation will assist in furthering the understanding of IPCC and its applicability.

Jun 1, 2010

By R G. Richards

The Australian glass sand industry produces some 2.8 million tonnes per annum of silica sand, of which about 2.0 million tonnes are exported and the rest is for the domestic market. Approximate production rates for each Australian state are listed. The variety of processing methods used in the currently exploited deposits reflects the size, location, and characteristics of the various deposits and the requirement of the end market/s. The industry uses to a large extent equipment developed for the separation of mineral sands, particularly as it applies to low grade heavy mineral deposits, where low cost, high capacity and metallurgically efficient equipment has proved eminently suitable for the production of the low value glass sands. The requirements of the domestic market, as well as those of the present and potential export markets are discussed covering quality requirements, distribution channels and other factors critical to success.

Jan 1, 1990

By C Garlick, O Gregory, H Rogers, B I. Winters, Z C. Ye

BHP New Zealand Steel produces iron from titaniferous ironsand by a direct reduction process comprising multihearth furnaces/rotary kilns/electric iron melters. The electric iron melter is a six-in-line rectangular submerged-arc furnace which takes the partially reduced ironsand (80 per cent metallisation) from the rotary kiln and completes the reduction process to produce iron of nominally three per cent carbon. As the melter operates at around 1500¦C and under very hostile conditions, it is near-impossible to obtain any basic operating parameters such as the velocity and temperature distribution in the slag and in the molten iron. As a first attempt to understand the operating conditions inside the melter, a scaled room-temperature model using wax and water to represent the slag and iron, was constructed. This paper will report on some of the preliminary model results on the temperature distribution.

Jan 1, 1995

The closure of the only professional mining school in New Zealand will mean that the minerals industry will have to explore other options to fill their mining professional positions. Globally mining is not seen as an attractive career option for young people and recruitment into mining courses is at a low level. Yet industry demands ever increasing competencies with respect to technology, environmental issues and legislation. This paper addresses this issue by first discussing the attributes required of graduate mining professionals. It then looks at alternative ways on how these can be met internationally and on the home front.

Jan 1, 1997

Applicaton of Agricultural Residues from Pyrolysis in Flotation of Black Coal

Sep 13, 2010

Within CRLÆs lifetime there have been a number of products that have proceeded through their life cycles. In each case market forces and technological advances have forced the cessation of the product. The company has then had to develop alternative outlets for its copper. Sometimes it has produced a similar product to fill the same market. In other cases the extra copper is sold as cathode. Today, CRL produces no semi-fabricated copper products and all cathode is sold. More recently, CRL has ventured into the sale of technology and manufacture of cathode motherplates. This area, whilst it is not what had been a traditional area of core business, has been found to be profitable.

Jan 1, 1998

Study on Flotation of the Low-Grade Magnesite Ore

Sep 13, 2010

Gold mineralisation at the Macraes Gold Project is hosted in the Hyde-Macraes shear zone and can be traced for ~30 km along strike, although economic resources are confined to a seven kilometre section in the vicinity of the Macraes  township. The shear zone, which typically dips at a low angle (~20¦) to the NE, is bounded by an upper hanging wall shear and a lower footwall fault. Mineralisation occurs along the hangingwall of the shear zone as well as in low angle concordant shears and stockworks. Ore types include graphitic cataclasites with variable amounts of quartz veining, 'lode schists' and quartz-vein stockworks. Mine geology and grade control activities are designed to ensure accurate definition of ore and waste as well as the accurate prediction of ore grade. Grade control involves an integrated process of blast hole sampling, geological mapping and geostatistical modelling. Geological mapping is carried out post blasting by means of excavating trenches across are zones defined by assay data. Conditional Simulation is used to model raw assay data to define ore-waste contacts and estimate ore block grade, although, geologically defined contacts have precedence. Low angle ore zones impart a wedge shaped geometry to many ore blocks. These ore blocks are bounded by contacts that can be selectively mined to, thereby reducing misallocation of ore and minimising grade dilution.

Jan 1, 2001

By K Palmer

Alluvial platinum was recovered during gold mining operations in Maud Creek, a tributary of the Howard River. Average electron probe analyses give Pt 88.75, Fe 5.27, Ir 0.70, Os 1.06, Pd 0.34, Ru 0.14, Rh 1.29, Cu 1.06. Rare grains of a Pt-Fe-Cu alloy are also present and an unusual feature of all grains is the relatively high rhodium content which finds expression in segregations of rhodium arsenide, cherepanovite. Platinum is found in the Orepuki area of Southland, where it is probably partly derived from the mafic rocks of the Longwood Complex. Rocks of the Rotoroa Complex, similar to those of the Longwood Complex, form bedrock in Maud Creek and are possibly the source of the Howard platinum. Alternatively, it might be derived by glacial transport from the Matakitaki ultramafic block 30 km to the southwest. Origin from the Rotoroa rocks is preferred as, if the Matakitaki rocks are part of the Dun Mountain Ophiolites, they might be expected to contain osmiridium rather than platinum. The ratio Pt:Ir-Os has been widely used to distinguish low Pt:Ir-Os ophiolitic from high Pt:Ir-Os gabbroic assemblages. Mafic complexes such as Longwoods, Darran, Rotoroa, and Riwaka might be expected to show similar high Pt:Ir-Os ratios and be targets for platinum exploration. Detrital platinum examined from the Parapara area, Golden Bay is mainly osmiridium, with rare grains of rutheniridosmine, very similar in composition to that found in concentrates from the Kaniere dredge, West Coast.

Jan 1, 1987

Separation of Nickel and Cobalt from Manganese, Magnesium and Calcium by Synergistic Solvent Extraction - From Batch Tests to Pilot Plant Operation The synergistic solvent extraction system consisting of Versatic 10/LIX63/TBP was used for the separation and purification of nickel and cobalt from synthetic laterite leach solution after iron removal. Very encouraging results were obtained for separating nickel and cobalt from manganese, magnesium and calcium. In batch tests, the organic composition of the synergistic system was optimised and very large synergistic shifts for nickel and cobalt were observed. The ?pH50(Mn-Co) and ?pH50(Mn-Ni) values were as large as 1.65 and 2.40, respectively. The extraction and stripping kinetics of nickel and cobalt was fast. Semi continuous extraction tests were conducted with a pH profile of 5.5/6.1/6.5 in three stages at 40¦C. The nickel and cobalt extractions reached 99.9 per cent with only 5 mg/L Ni and <1 mg/L Co left in the raffinate. With two stages of scrubbing, only 2 mg/L Mn and less than 1 mg/L Mg and Ca were left in the scrubbed organic solution. With two stripping stages, the stripping efficiencies of Ni and Co reached over 95 per cent. A fully continuous pilot plant operation was conducted successfully for 280 hours. With an O/A ratio of about 2 and a pH profile of 5.5/5.8/6.0/6.3 for the four stages EX1/EX2/Ex3/EX4, both nickel and cobalt were almost completely extracted. Using a pH profile of 5.4/5.0 for SC1/SC2, the manganese scrubbing efficiency was over 96 per cent. Using three strip stages, over 98 per cent Ni and 99 per cent Co were stripped with only 64 mg/L Ni in the stripped organic solution. The nickel concentration in the loaded strip liquor reached 83 g/L, resulting in a ?Ni of over 28 g/L. The chemical stability of the system was also assessed over 12 weeks under proposed industrial operating conditions. Operation exclusively under strip conditions at 50¦C and 40¦C resulted in LIX63 oxime half lives of 1.1 and 2.1 years, respectively. Operation exclusively under extract conditions at 50¦C and 40¦C resulted in oxime half lives of 0.26 and 0.82 years, respectively. Losses of Versatic 10 were less than four per cent.

Sep 13, 2010