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By Silitonga M

Generally, the acceptable parameter for predicting the intensity of ground vibration due to a blast is the amount of explo ive u ed and the distance from the explo ion. A eries of closely controlled tests were carried out and it was observed that the degree of confinement or burden of an explosive charge play an important role in the variation of the transmitted magnitude of the shock wave through the ground.The intensity of the shock wave increases with burial depth or with greater confinement of an explosion until a critical depth is reached.Beyond this critical depth, the magnitude of ground vibration remain constant. This is an important finding, which explains the anomalies between the expected level and the monitored ground vibration in a particular situation.

Jan 1, 1984

1991 New Zealand Branch Annual Conference û Appendix

Jan 1, 1991

Investment decisions in the Australian mining industry are often made without awareness of the impact of risk on project outcomes. A fundamental change in thinking is required to move away from the traditional attitude of æcushioning the blowÆ towards a measured approach to project risk. Such an approach involves quantifying and understanding project uncertainty so that investments may be shielded from downside risk while at the same time exposed to upside potential. Communication and collaboration between study teams and corporate financial managers must be improved before the industry can improve its project investment record. Monte-Carlo simulation provides a way to quantify and understand investment risk, but its accuracy depends on how well the variability of input parameters is estimated. Research in this area is currently centred on quantifying uncertainty in mineral resource estimation using new conditional simulation techniques, but a less-rigorous method can be applied in practice to begin the education process and develop the required awareness at board level.

Jan 1, 2003

By Arndt MB, Bamberg S

The evaluation of risk is becoming more important in the siting of mining operations in the United States as well as the rest of the world. The determination of environmental, economic, as well as health and safety risks is an important step in the planning of any mining operation. Hydrogeology plays an important role in pre-mine planning and in the determination of these risks. The mine operators must determine if ground water would inhibit mining in any way. Factors which are important to consider include mine dewatering economics, slope stability, and other adverse hydrologic impacts. This paper presents methodologies for the characterization of hydrogeological risks for a mining operation. First of all, the term risk analysis is defined and its utility is addressed. Then, stepwise methods for performing a typical risk analysis are presented. Finally, the application of risk analysis to hydrogeology in mining is given. With slight modification, it is believed that these methodologies can be used to evaluate the hydrogeological risks for any mining operation.

Jan 1, 1988

The State of Western Australia has a land area of 2 525 000 km2, and is well endowed with minerals and petroleum products. In 1989 - 90 these products were valued at nearly A$10 500 million.

Jan 1, 1992

By Johnson G. D

Confidence in Yakabindie becoming a truly cost competitive nickel project has risen recently because of: ò the emergence of an economically effective contract mining climate; ò the delivery of cheaper energy via the Goldfields Gas Pipeline; and ò the development of the Yakabindie Process for production of nickel cathode and cobalt by-product directly from sulphide concentrates at site, dramatically cutting capital and operating costs compared to the conventional route. Development of the Yakabindie Process was a result of 'necessity being the mother of invention'. Yakabindie can now break out of the trap of relying on existing downstream processors to treat an intermediate, and instead the project can gain direct market access. The very attractive cost advantages demonstrate that hydrometallurgical processing of sulphide concentrates is a worthy prize. Improved cobalt recoveries, and tolerance of higher levels of magnesium and arsenic than allowable by smelters, are further advantages of this approach. Leach residues are combined with much larger quantities of naturally alkaline flotation tailings and remain at site. As a result the process is more environmentally sensitive than the conventional smelt/refine route, with no sulphur dioxide gas emissions and 'metal only out the gate'.

Jan 1, 1996

By S Strohmayr, R Harvey, A See

Ernest Henry Mining Pty Ltd started production in August 1997. The Ernest Henry orebody consists of two distinct parts, a complex supergene ore zone overlying a primary ore zone. The economic copper minerals in the supergene ore were chalcocite, bornite, secondary chalcopyrite and native copper while the primary zone has only chalcopyrite. The variability of the supergene zone made concentrator operation difficult and predicting metallurgical performance using mineralogy essential to establish the capabilities of the concentrator. A paper presented at the 1998 Mine to Mill Conference entitled Mineralogy Controlling Metallurgy at Ernest Henry Mining (Barnes, Strohmayr, Brindley and Munro, 1998) presented the testwork and initial plant surveys that showed that the mineralogy of the ore controls the metallurgy of the concentrator. This paper presents the data obtained from the subsequent years of operation treating both the supergene and primary ore types. A review of the actual supergene mineral distribution in feed and subsequent recoveries compared to those predicted as part of the flowsheet design is also presented.

Jan 1, 2003

The electrochemical dissolution of gold and other noble metals in hydrochloric acid using alternating current has been investigated. The experimental results show that this technique is efficient for dissolving pure noble metals and offers prospects for their extraction from wastes and poor ores.

Jan 1, 1992

By Morley I. W

Offshore minerals legislation has been introduced to provide jurisdiction over the exploration and recovery of mineral resources, particularly petroleum, from the territorial waters and parts of the continental shelves adjacent to coastal states. Ratificat- ion of the 1958 Geneva Conventions on the Law of the Sea has provided some measure of international agreement amongst signatory powers. Because the relationship of the Australian States to the Commonwealth in their federal system, the Australian offshore petroleum legislation is of particular interest. The customary role of the States in mineral resources management, which has extended to the offshore, is under challenge from recent unilateral Commonwealth Government legislative actions in the fields of mineral resources jurisdiction. Environmental considerations provide an additional issue, as yet unresolved, with the delay in submission of the Report of the Great Barrier Reef Petroleum Drilling Royal Commissions

Jan 1, 1974

By Liu H, Chen S

Natroalunite is one of colouring minerals in kaolin. In this investigation, natroalunite, on which Ca(II) was adsorbed, was flocculated by HPAM and kaolin was depressed in suspension. The adsorption of Ca(II) on the natroalunite surface was studied by zeta-potential measurement and Auger Electron Spectroscopy analysis. Ca(II) was adsorbed more on the natroalunite surface than on the kaolin surface. The mechanism of Ca(II) adsorption was considered to be chemical adsorption on natroalunite and to be physical adsorption on kaolin. It has been found that Na6P6O18 and Na2Si04 can strongly affect Ca(II) adsorption on the surface of kaolin, but weakly on the surface of natroalunite. The effects of degree of hydrolysis and the molecular weight of HPAM, the effect of pH and the effect of Ca(II) have been studied. The kaolin ore, containing SO3 1.05 per cent has been processed with this method. The products only containing S03 0.36 per cent and the weight ratio of concentrate 52.27 per cent were Obtained.

Jan 1, 1993

By Somasundaran P

Controlled modification of mineral/liquid interfacial properties by adsorption is critical for mineral processing operations such as flotation, filtration, dispersion and flocculation. Ionic/nonionic surfactant mixtures usually show enhanced surface activity and salt tolerance over ionic surfactants, and this is especially beneficial for flotation of salt type minerals in which case dissolved multivalent cations in high concentrations usually cause loss of anionic surfactants by precipitation. Adsorption of nonionic/anionic surfactant mixtures on kaolinite has been studied with sodium dodecylsulfate as the anionic surfactant and octaethyleneglycol mono-n-dodecylether as the nonionic surfactant. Synergistic interaction between these surfactants was found to cause adsorption of the nonionic surfactant with its hydrophilic chains protruding into the bulk, leading to substantial changes in flotability and dispersion characteristics of kaolinite. Similarly, hydrophobicity changes are observed also' for silica particles upon adsorption of nonionic ethoxylated alcohols owing to possible changes in the orientation of the adsorbed surfactant species at the interface. Also, based on the results obtained with surfactant adsorption, a hydrophobically modified polymer was used successfully to disperse graphite particles in aqueous solution.

Jan 1, 1993

The scope, pace and depth of mining is creating a need for improved ground control strategies to meet mine safety standards. Ground control and associated conservation problems relating to subsidence and the disposal of mining and metallurgical wastes can be resolved by mine filling with selected reject materials. The lack of suitable criteria to evaluate the applicability of such materials and especially cemented forms of fill is considered. Sulphide wastes, which are prone to oxidize, and cement are inexpensive mine fills, but their incorrect use can give rise to problems which are briefly described. Research work concerned with the utilization of sulphide wastes such as mill tailings, to produce fill with self-cementing properties has shown that the development of cohesion and strength is attributable to natural oxidation processes controlled by the physical and chemical composition of the fill mass. The cementing is caused by a number of oxidation products, and is most effective when the mineral pyrrhotite is present. The concepts of fill design are outlined and various criteria for assessing durability and deformational properties are proposed. Specimens prepared in the laboratory are capable of attaining unconfined compressive strengths up to 28 MN/m2.

Jan 1, 1973

The Mining Act (1992) and the Petroleum Act (1980) provide for the Government of Papua New Guinea (PNG) to take up equity holdings in mining and petroleum projects. The price the Government pays for its share is based on the historical cost of exploration and development on the project to the date of government equity acquisition. The equity level to be acquired is not fixed and ranges up to 30o for mining and up to 22.5s for petroleum at the discretion of the Government of the time.The objective of this paper is to examine the pros and cons of State equity holdings in PNG from the point of view of both the State and the developer. Using an economic model of the PNG mining taxation system an assessment is made of the effective return on investment received by the State from such equity holdings. The results are compared with government revenues from other taxation measures.

Jan 1, 1994

Nearly eighteen months ago Newmont Waihi Operations joined with the local district council and members of the Waihi community in the initiation and running of a community liaison forum.   This forum û the Waihi Community Consultative Committee (WCCC) û was set up with the objective of improving communication, providing a forum for discussion and ultimately working through a range of issues relating to the future of the town and district after the projected closure of Martha Mine in late-2006.   After 18 months of meetings where all represented groups have presented their views, the challenge now is to work together to investigate likely options, seek sources of funding, produce business proposals and plan for the future of Waihi in what we call the Golden Legacy Project.   This paper backgrounds the companyÆs experiences to date, the issues the group has addressed and its proposals for the future. Methods employed to set up an effective community liaison forum are considered, drawing on specific examples from the WCCC. The actions and structures required to ensure effective and ongoing community æbuy inÆ at all levels are also discussed.   This paper develops themes addressed in Taking it to the Streets presented in 2003.

Jan 1, 2004

By Upfold RW, Nguyen VU

The extraction and utilisation of metals and materials is the basis of modern civilisation, and will remain so for many decades, Traditional metals are facing some challenges and research is needed in specific areas, to improve metal extraction processes, to develop processes for newer metals and minerals, and to develop new applications, The shortage of metallurgists now becoming apparent in Australia is a further significant problem that needs urgent attention, and much more publicity is required for the Mineral Industry, as well as for the utilisation Industries,

Jan 1, 1986

By S Porter, R Woodall, N Weeks

Nelsen, Porter and Wilson (1996) provided some preliminary concepts for the design of the Melbourne City Link tunnels. At that time, the City Link project was in the early design phase whereas now it is nearing completion. This paper provides details of the actual design adopted for the various sections of the tunnels as well as some commentary on the design process. The tunnels form a critical element of the project and the design of both driven and cut and cover tunnel sections is a significant factor contributing to successful project execution. Geology, hydrogeology, site constraints, traffic management and program were important design inputs. Design for the cut and cover sections in particular varied significantly in response to these differing inputs.

Jan 1, 1999

The Nelson province was chosen as the prime area for rhenium sampling, based on its mineral associations. Sample preparation involved benefication by grinding and flotation. A modification of published procedures for rhenium analysis was developed and the results compared with those obtained for molybdenum on the same samples using atomic absorption spectroscopy. The results of the analysis for both metals is discussed and the relationships between rhenium and the molybdenum mineralisation of this region is commented on. A metallogenic province is defined for molybdenum and rhenium and the tectonic setting for this is discussed. Some consideration has been given to rhenium possibilities in Fiordland and the Coromandel Range.

Jan 1, 1980

By A E. McElnea, M A. Martens

An 18-month project was undertaken to test the effectiveness of controlled daily tidal exchange augmented with hydrated lime treatment of surface waters as an approach for remediating a severe acid sulfate soil disturbance at East Trinity, Cairns, north Queensland. Actual acid sulfate soils were producing hazardous levels of acid and heavy metal contaminants and degrading approximately 720 of the 940 ha East Trinity property and the adjacent foreshores. A government-led research team established a series of research projects with the aim of characterising the site (soils, water, terrain) and testing the effect of the lime-assisted tidal exchange management strategy on soils, water, sediments and biota.

Jan 1, 2003

From depths of 400 - 600 m, coal is transported by a conveyor in a drift or a bulk winder in a shaft, whilst men and/or materials are transported by a slope hauler or a cage winder. Assessment of the effect of alternative combinations on the key cost factors - output, capital, labour cost and construction time - allows the optimum choice for particular circumstances, there being no uniform solution.

Jan 1, 1976

Although geophysical methods of prospecting have proved indispensable in the search or oil deposits elsewhere; it is only 'in recent years that they have been used to any significant extent in Australia. The increase in their use has been quite remarkable over the past two or three years, due in Sao small measure to the encouragement given by means of Commonwealth subsidy. There is no doubt that the use of' geophysical methods will coxi-tinue to increase and this increase could be greatly accelerated as and when oil is discovered in commercial quantities,This review of their use A in Australia and the remarks and statistics are confined to work on the mainland. There has been, a substantial amount of geophysical work in Papua, but as operating conditions are so very different to the mainland Papua has been regarded as a separate province.

Jan 1, 1962