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By K Thorpe

Amorphous silica deposits have been identified at Tikitere and Taheke near Rotorua. Two areas at Tikitere have been surface sampled and drilled to establish a resource of amorphous silica in excess of one million tonnes. A pilot plant was established to develop a process to manufacture a high quality super pozzolanic material. This development process took two years before a commercial product was introduced to the construction industry in 1996. The amorphous silica product, marketed as Microsilica 600, is used as a pozzolanic material to produce high quality strong and durable concrete, sprayed tunnel linings, mortars and grouts. Microsilica 600 has been used locally and exported to 11 countries.

Jan 1, 1999

Iron Concentrate Synthesised from Waste Ferrous Sulfate Produced in Titanium White Preparation

Sep 13, 2010

By A B. Christie

The Institute of Geological and Nuclear Sciences' Mineral Resources Programme is currently carrying out research under two major projects:   HAREM (Hauraki Andesite Rhyolite Epithennal Mineralisation) The Hauraki Goldfield lies within a belt of andesite-dacite-rhyolite volcanics of Miocene Pliocene age which is underlain by a basement of Mesozoic greywacke. It contains some 50 separate epithermal gold deposits and is a world-class gold and silver producer. The HAREM project is aimed at improving models of the epithermal gold mineralisation, and to better understand the processes and controls of origin, transport and deposition of the gold.   MARGO - (Marlborough Gold) The MARGO project is aimed at determining the geological factors that controlled the formation of the Mesozoic mesothermal gold-antimony-tungsten deposits in the Marlborough Schist belt. Following reconnaissance work on 12 deposits, our current work is concentrated on deposits in the Wakamarina valley.

Jan 1, 1994

By P Maillet, A J. Crawford, S M. Eggins

TheFiji Islands are remnants of a once continuous Solomon-Vanuatu-Fiji-Tonga volcanic arc (the Vitiaz arc), located at the boundary between the Indian-Australian and Pacific plates. They record a history of: (i)                  arc volcanism the late Eocene to late Miocene, (ii)                an extensive magmatic response to arc rifting (5.5 - 3.0 Ma) during which volcanism was dominated by shoshonitic to tholeiitic basalts, and as rifting continued, (iii)               a transition from arc to intraplate volcanism.   The Hunter Ridge-Hunter Fracture Zone separates the inactive South Fiji Basin from the actively spreading North Fiji Basin, and has been considered to be a transform zone, almost parallel to the motion vector of the Australian plate. However rocks dredged during the 1993 æAlizeÆ cruise, from along the northern part of the Hunter Ridge are typical arc tholeiites, and therefore demand that subduction has occurred beneath the Hunter Ridge sometime during the last ~5 Ma. The Kadavu Island group, south westernmost Fiji, lies at the north-eastern end of the Hunter Ridge-Hunter Fracture Zone, and possibly results from oblique subduction of South Fiji Basin oceanic crust, which may have accompanied the anticlockwise rotation of Fiji during opening of the North Fiji Basin. These islands consist dominantly of 3.4 - 0.5 Ma old medium-high K andesites and dacites, with many traits typical of subduction-related volcanics, ie predominance of intermediate members (55 - 65% SiO2) no Fe enrichment, TiO2<1%, and negative Nb-Ta anomalies. These features contrast strongly with volcanics from elsewhere in Fiji around this time, where volcanic centres produced Om-like intraplate olivine basalts. The Kadavu Islands become gradually younger to the southwest, and show a significant decrease in K2O with time. The north easternmost islands (Astrolabe islands) containing the oldest rocks (~3 Ma) have shoshonitic affinities and are considered to be of similar age and composition to the youngest shoshonites found elsewhere in Fiji.

Jan 1, 1995

The 115-year history of the Hall-Heroult process for production of aluminium has been characterised by a sustained technology-driven improvement in costs and productivity. In the past decade the industry has effectively transferred best practice into older technology with improvements through computer control of the process, and redesign of cell linings using computer modelling . Incremental development is now at the point where diminishing returns will apply for further technical improvement effort however, until the gap between technical limits and current best practice is addressed through major process redesign. The process remains a long way short of its technical limits in energy consumption, carbon anode consumption, cell life and product purity. Investment cost in new capacity is very high, supporting the retention of older and less efficient technology and hence limiting the application of best practice in environmental performance and occupational health exposure. The industry is a major emitter of greenhouse gases yet the process has the potential to release oxygen as the primary waste. All of the above issues will be addressed in the new century, but only through commitment to the necessary long-term research and development that is required to achieve a redesign of the process.

Jan 1, 2000

An Application of Depressant BK510 in Separation of Molybdenite and Bismuth by Flotation

Sep 13, 2010

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

By G Baird, M Seto

Reliable evaluation of in situ stress is an important phase in the analysis and design of underground excavations, particularly for evaluating the stability of underground structures to prevent failure or collapse. A technique for the estimation of the full stress tensor based on acoustic emission (the Kaiser effect) is being developed and trialed at the WA School of Mines. The result obtained compare well with the standard over-coring method. The advantages of the technique are that it is relatively cheap, non-time consuming and is applicable to in situ stress measurements at depth in remote regions.

Jan 1, 2002

The selection of the mining fleet can have as much of an effect on the efficiency and effectiveness of an operation as the mining method. This is not to say that inefficiencies are only attributable to inappropriate equipment selections, these aspects have many factors but are not the subject of this paper.This paper will give an overview of equipment selection processes that have been utilised to date. It will also look at the increase in application of study programs/simulations from an aspect of accuracy, as well as the importance of enabling the analysis of multiple sensitivity scenario planning. An aspect that is increasingly important in project planning with commodity market movements.Another aspect that is increasing in popularity is that of automation, what effect does this have on equipment selection? What additional aspects need to be taken into consideration when assessing Automation of equipment from the beginning of a project as well as introduction into an operating mine?Once the selection process has been finalised and equipment implemented, how do we, as an industry, 'close the loop' through analysis of estimated versus actual equipment application?

Dec 6, 2010

The Dynamics and Thermodynamics of Absorbing Lithium of Ion Sieve Preparing Pollymetallic Nodules

Sep 13, 2010

By P Wood

Loy Yang Power (LYP) owns and operates a 2160 MW brown coal fired, base load power station in the Latrobe Valley, Victoria, Australia (Loy Yang A). It also owns and operates a brown coal mine that supplies fuel to its own power station and a nearby 1000 MW power station owned by International Power (LoyYang B). The mine supplies 32 Mt of coal per annum from an open pit, which is currently about 4 km long by 2 km wide and 180 m deep. LYP has 500 employees and a substantial amount of work is also carried out by contractors and consultants. GHD Pty Ltd(GHD) has been contracted to provide mine planning and earth sciences expertise. GHD is an international professional services company that operates globally in many market sectors including mining, industry and the environment. The company has major offices in Melbourne and also within the Latrobe Valley. This paper sets out the experiences that GHD and LYP have gained in establishing a unique alliance arrangement for GHD to provide a range of mine planning, earth science, dam surveillance and environmental services to LYP. The underlying philosophy of the alliance is to closely align the objectives of the two companies such that GHDÆs recompense for service delivery is proportional to the benefit achieved by LYPÆs business. Quality of service, whole of life costs and risk management are important aspects and are reflected in key performance indicators against which GHDÆs performance is measured. Currently GHD provide 20 000 hours of labour to LYP per annum, which are delivered by up to 120 staff who possess the required diversity of skills. The paper explains how the contract was initially let as a conventional service agreement and explains why the contract was transformed into an alliance. It then illustrates the operation of the alliance with reference to the 2006 work program. The paper concludes with thoughts on how the arrangement can be further developed for the future to the benefit of both parties.

Jan 1, 2006

On the first of October 1991 two significant pieces of legislation came into force. Both of these are relevant to the allocation and use of minerals in New Zealand . They are the Crown Minerals Act 1991 and the Resource Management Act 1991.   The full legal implications of these is not fully known because the Planning Tribunal and the superior courts have not as yet had to deal with them in any detail. However, the thrust of the legislation is clear and it is appropriate to give an overview of how the statutes will operate in tandem if you are seeking to pursue or oppose any prospect, exploration or mining of Crown Minerals in New Zealand.

Jan 1, 1992

Two Variable Real-Time Algorithm for Cone Crusher Control

Sep 13, 2010

By A F. Cooper

Otago Schist in the Mount Patriarch, High Burn and Cameron Creek areas of northwest Otago grades from textural grade IIA in the east to textural grade III in the west. The entire region is of the actinolite-pumpellyite metamorphic facies. Lithologies in the area are interbedded turbidite sequences comprising pelite and psammite together with pebble conglomerate, greenschist and metachert horizons. The mineral assemblage of the schist is typically quartz-albite-epidote-actinolite-pumpellyite-chlorite-stilpnomelane-calcite. A good foliation is well defined in the area and is predominantly parallel to bedding, except in hinges of mesoscopic isoclinal folds. The structure of the area appears to be defined by a large southwest plunging isoclinal fold defined by bedding with a steeply dipping axial planar foliation. Kink folding and dextral strike-slip faulting in the area postdates the ductile phase of deformation. Pods of rhodonite, rhodochrosite, spessartine garnet, coombsite, caryopilite, Mnstilpnomelane and Ni-Cu-Zn sulphides were found in concordant metachert layers in the Mount Patriarch area. Metachert was also found in float in the Cameron Creek area. Malachite occurrences relating to copper mineralisation were also noted in a green metachert horizon on the eastern flank of Mount Patriarch. The coombsite, in only the third observation worldwide, is the most Fe-rich variety reported.

Jan 1, 2003

By J Sibbel, K Goh

A key issue facing mine managers in remote locations in Australia and overseas is that of managing a fly-in, fly-out (FIFO) workforce. Current Australian research (Sibbel, in prep) indicates that FIFO employees and their families do not differ from the general population in terms of their overall mental health and the well-being of their family relationships. However, they do face unique issues/pressures associated with the lifestyle, the impacts of which are dependent on the policies and practices of the company as well as individual coping and support mechanisms. Successful management of a FIFO site and its employees therefore requires specialist knowledge and skills beyond those of a solely residential operation. The well-being of the FIFO workforce depends on both site and individual employee characteristics, and has implications for productivity and turnover, as well as safety and health. In addition, although FIFO separates individuals and their families in time and space, the interaction between work and home must be acknowledged and taken into account. Drawing on findings from recent Australian and international FIFO research (eg Annear, Poot and Kingston, 2006; Beach, Brereton and Cliff, 2003; Brereton et al, 2006; Gallegos, 2006; Keown, 2005; Parkes, Carnell and Farmer, 2005; Sibbel, 2001, 2004, in prep; Shrimpton and Storey, 1996; Storey, 2001; Watts, 2004) this paper discusses key understandings of both the positive and negative impacts of FIFO employment on employees and their families, and provides practical management strategies as an aid to the development of best practice. Individual impacts including fatigue and loneliness, as well as family issues such as communication, continually changing roles and responsibilities and the impacts of regular parent absence are key areas which can be ameliorated by appropriate management understanding and action. A flexible framework approach is presented that is suitable for a diversity of operations, including principal and contractor workforces of different sized operations.

Jan 1, 2006

Kinetics of Reclamation of E-Waste by a Bioleaching Route

Sep 13, 2010

By R Miller, D Hawcroft

The business environment is never still and there has been enormous change in demand, technology and opportunity during the last decade. In order to succeed it is necessary for organisations to change the way work is planned, scheduled and carried out. This is necessary just to survive over time. The success or failure of the business is strongly influenced by people; the way they work, the way they are guided and their feelings about being part of both a team, as well as an organisation. Our Sustainable Integrated Management System (SIMS) philosophy is built on the belief that people want to be constructive and creative and it is their environment and working relationships that influence how their energies are directed.

Jan 1, 2000

By N Hungerford, A Coote, S Doyle, D Henderson, F Della-Pasqua

A systematic, detailed airborne geophysical programme carried out in the Taupo Volcanic Region (TVR) in 2005 by Glass Earth NZ Ltd culminated in the identification of 21 epithermal gold targets. In this paper we present the follow up ground-truthing results from the first target drilled, Tahunaatara (TAH).   The Tahunaatara target was identified by means of a multi-disciplinary integrated approach (ôdata interventionö) that defined and ranked the target as being highly prospective for epithermal gold mineralisation. A follow-up ground resistivity survey over the target area revealed the presence of a ôresistorö buried beneath an extensive cover of recent volcaniclastic material. Geochemical soil sampling carried out in conjunction with the resistivity survey yielded anomalous gold values.   The host unit at TAH consists primarily of flow banded rhyolitic lavas, volcaniclastic deposits and tuffs of the Ohakuri Ignimbrite with small outcrops of silicified bedded breccias forming local topographic highs. Results from the first orientation drill hole show wide zones of intense silicification, clay alteration and mineralisation. Sulphide mineralisation is disseminated throughout the core in association with hydrothermal replacement and also occurs in association with quartz veins and infill in fractures (sulphide-only veinlets as opposed to quartz + sulphide veinlets). Textural evidence from drill core indicates that hydrothermal fluid flow was multi-staged with potential for multi-stage gold, and other elements. The presence of polymictic hydrothermal eruptive breccias indicates a hydrothermal vent system.   Alteration varies from argillic to silicic, with pervasive adularia and vuggy silicification also present. Chlorite is minor and associated with quartz, illitic clay and adularia. Assay results currently available confirm the presence of anomalous gold values in association with zones of vuggy silica deposition and intense silicification.

Jan 1, 2006

Cretaceous to Cenozoic sedimentary basins in Western Southland include a wide range of non-marine and marine sediments, in a structurally complex setting dominated by major fault systems. A reassessment of their mineral potential confirms large quantities of nonmetallic minerals (limestone, aggregate, marl), and smaller reserves of bituminous coal, lignite, clays, and oil shale. Hydrocarbon potential is largely untested. Metallic minerals are present in trace amounts, apart from platinum group minerals and some detrital gold. In the offshore area, seismic data suggest the hydrocarbon potential is significant. The Orepuki area has the most interest onshore.

Jan 1, 1992

Enterprise Optimisation is a methodology for increasing the value of mining and mineral processing operations through better long-term planning decisions. It involves a combination of ten mechanisms which deal with decisions at different stages of the value chain. A decision made at any point in the chain potentially affects the decision for all other points in the chain. The key, therefore, is to optimise them simultaneously. The Enterprise Optimisation approach can be shown to produce increases of five per cent to 35 per cent or more in net present value (NPV), even when several optimisation methods have already been applied. This paper steps through an example case study, illustrating the effect of each mechanism and how they can work together to develop greatly improved results. This example results in a series of counter-intuitive outcomes, which challenges conventional management practices and typical organisational objectives based on organisational silos.

Dec 6, 2010