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A resume covering currently accepted views on blasting vibration measurement, human response, and criteria for damage is presented as background information for readers who are not conversant with blasting vibrations. This is followed by sections on vibration level estimation and blasting techniques to control vibration. Emphasis is placed on making use of the scatter in the delay intervals of half-second delay detonators, the use of smaller explosive charges for early delay numbers, and the non- use of zero-delay (instantaneous) detonators in cer`a. n cases.

Jan 1, 1976

To secure a sustainable competitive advantage some smelters may need strategies based on flexibility in feed and product ranges depending on immediate future projections of profitability. This paper explores the technical requirements for strategic diversity in smelting, leaving procurement, marketing and contractual considerations aside. The days when a smelting operation is tied specifically to say only processing zinc concentrates are perhaps drawing to a close. While internationally traded mineral concentrates are available, attractive business opportunities must exist for fully diversified custom smelters. Certain new and emerging technologies have inherent characteristics that are evaluated in this context. The paper identifies the basic building blocks that will permit such a scenario and assesses the technical feasibility. The ability to respond flexibly to environmental pressures is highlighted as being of paramount importance.

Jan 1, 1996

By Clarke B. N

The Olympic mine is currently and development to 1988. The mine practice is, and number of factors. Dam copper-uranium-gold undergoing construction start production in May ventilation design and will be determined by a These include: 1. Mining method and degree of mechanization. 2. Presence of radon emanating material. 3. High virgin rock temperatures at relatively shallow depths. 4. High ambient air temperatures in Summer.

Jan 1, 1988

By Browne TJ

On 13 October 1993, a shallow earthquake registering 7.1 on the Richter Scale occurred near Tauta in the Finisterre Range of Papua New Guinea (PNG) killing 37 people. The aftershock series lasted three months and resulted in considerable landslide damage that destroyed villages, food gardens and airstrips, and blocked rivers causing catastrophic flooding. These effects have irrevocably altered the form of many of the valleys and rivers draining into the Markham and Ramu valleys.The earthquake occurred in a pilot study area for a landslide hazard mapping project being carried out by the PNG Geological Survey that commen-ced in April 1993. Comparisons made between areas identified as unstable during the study with those damaged by the earthquakes show good correlation.It is concluded that aerial photograph and Landsat TM imagery interpretation can be used with a high degree of confidence to identify potential landslide hazards in mount-ainous terrain. Landslide hazard maps are promoted as a tool for use in the route planning of roads and powerline corridors, as well as for identifying vulnerable communities.

Jan 1, 1994

By Naik J. S G

The plant practice plays an important role in production and productivity. Men, material and machinery have to be judicially utilised to achieve maximum output with minimum cost. Improvements in technology should be incorporated at an appropriate time and place. The personnel concerned should be properly trained and motivated to receive the changes in machinery and technology. Strict adherence to prescribed parameters, optimum utilisation of man, machinery and operating supplies help in the smooth functioning of the plant and in achieving maximum gains.

Jan 1, 1992

By Yusuf R

Many heap and dump leaching processes involve competitive, complementary and sequential reactions between multiple minerals and reagents. A comprehensive model has been developed to deal with these complex chemical interactions which is based on diffusion control of the reaction rates. All of the mineralogical and chemical data are obtained from representative samples of the ore or the chemical literature. These properties have been incorporated in a general way, making the model applicable to a range of ore-process systems. The simulation is used to predict the absolute reaction rates and can be used before any leach tests are carried out on the ore itself. The applicability of the model and some tests of its validity are presented.

Jan 1, 1984

By Houlihan RN, Landau J

A reciprocating plate column is described in which two sets of perforated plates are mounted alternately on two shafts and are reciprocated with a phase difference of 1800 between them. It is shown that such a column is mechanically superior to the previously proposed types: under practical operating conditions the pressure fluctuations at the base of the column are only a small fraction of the static head. Furthermore, mass transfer experiments with the system tributyl phosphate in kerosene- acid aqueous solutions of uranyl nitrate show that both high specific throughputs and reason- ably good efficiencies can be attained in this type of column. A comparison with the more conventional extraction equipment (mixer -settlers, pulsed columns) on the basis of residence time per equilibrium stage indicates the potential of reciprocating plate columns in hydrometallurg- ical application, especially in which the requirements of separation efficiency are modest while the scale of operation is large.

Jan 1, 1975

1991 New Zealand Branch Annual Conference û Appendix

Jan 1, 1991

By Lama RD

The paper outlines the development in the control of dust in Australia over the last 20 years. Factors influencing dust make at the faces are discussed. The effect of high production systems is analysed. Changes in dust standards and results of dust sampling on longwalls and continuous miner panels are given. Research conducted on air curtains and water infusion on dust control on longwall faces is presented along with recommendations for future research. It is found that both dust curtains and water infusion can cut dust mak by 50" each when applied separately.

Jan 1, 1988

By Gemmell J. B

Zinc-bearing massive sulphide deposits have been mined in Tasmania since 1900. The current major producers are Hellyer and Rosebery, with total resource tonnages (mined plus reserves) of 16 Mt (million tonnes) and 24.8 Mt respectively. These deposits belong to the class of seafloor volcanic-hosted massive sulphides (VHMS) and are located within the Mt Read Volcanics, a narrow belt of continental margin calcalkaline volcanics of Cambrian age. Compared to other Australian VHMS deposits, and world-wide MVT and Sedex deposits, the Tasmanian examples clearly stand-out due to their high metal grades, averaging over 17 per cent Pb+Zn. The deposits vary in morphology from mound style (Hellyer) to sheet style (Rosebery) with other combinations including stacked lenses (Que River) and disrupted cross-cutting bodies (Hercules). All deposits show the classic VHMS zonation from an Fe-Cu-bearing base to a Zn-Pb-Ba-rich top. Zinc, gold and silver tenor commonly increases toward the stratigraphic top of the deposits. The ores have been deformed during regional metamorphism, resulting in folding, shearing and recrystallisation of sulphide lenses. In addition to the major deposits, a number of small massive sulphide prospects occur throughout the volcanic belt and the potential for the discovery of further large, deeply buried deposits remains high.

Jan 1, 1993

By Williams RC

Overlying the coal deposits of the Sydney Basin are several lakes and other bodies of water. These include the Pacific Ocean, Lake Macquarie, the Tuggerah Lakes and the stored waters of the dams of the New South Wales Metropolitan Water Sewerage and Drainage Board. The coal beneath these bodies of water amounts to hundreds of millions of tons. Colliery workings have approached these areas of water and in some instances first 1"orkings of bord and pillar have taken place oi_eshh the water. he problem which now faces mine manage- and other interested authorities involves the determination of the maximum ;mount of coal which can be safely extracted from beneath the water. There are many factors to be considered including the depth of cover, seam thickness, geological details and strata movements.

Jan 1, 1972

By T Kitajima, T Kawaguchi, T Nakamura

Carbothermic reduction of iron oxide is an attractive mechanism to produce metallic iron, since it can directly utilise coal as both reductant and fuel. To improve energy efficiency and productivity of the metallic iron production based on this mechanism, the combustion bed process packed with the composites of iron oxide and coal powder was experimentally evaluated. The process has a potential of high heat efficiency since it can automatically utilise the heat of reduced materials as that necessary to the subsequent reduction of the composite by a large heat exchange rate between the packed particles and gas flowed across the bed. However, it is hard to perfectly prevent the reoxidation of formed metallic iron in the bed. The present paper reports the effect of coal content, pellet size and so forth on the reduction/metallisation degrees of the samples after the reduction experiment. It also discusses the effect of pretreatment of the composite pellets using CaO bearing materials to suppress the reoxidation of formed metallic iron in the bed.

Jan 1, 2000

TABLE OF CONTENTS:Introduction.Chemical Composition-lignitic coal-earthy coal-pollen coal-fern coal-nature of ash in the several coal types.Carbonization Tests.Air Drying of the Coal Types-rate of drying in the coal face-relative rates of diffusion-differential slacking of coal types-rate of oxygen absorption.Origin of the Coal Types-colour difference-cause of different rates of diffusion.Practical Significance.Summary.Acknowledgments.The Yallourn brown coal seam, where exposed in the Yallourn Open Cut, and the Latrobe brown coal seam, where exposed in the Yallourn North Open Cut, are both distinctly bedded. Close inspection shows that both seams consist of beds of coal from 1 to 10 ft. thick, which on drying out develop differences in colour and in their, shrinkage crack patterns. Tliese differences become apparent in the...

Jan 1, 1947

By Mansor A. N

Results are reported for the computer simulation of heap leaching of mixed copper oxide and sulphide ores. They resemble those obtained from testwork in terms of a substantial peak in the copper concentration of the pregnant solution, an initial period when no copper emerges and a lengthy period towards the end when the copper concentration and the daily increment in copper recovery are low. The simulation can be used to forecast process results before any column or similar testwork is performed. Potential applications of the simulation to process design, operating strategy and optimisation are discussed. Three modes of operation are identified that correspond to different performance patterns and dependencies on ore and process variables. The relative merits of different operating strategies for approaching the ideal performance are being investigated. For process design and development purposes, the simulation may be used with a limited testwork programme to achieve significant savings in time and resources.

Jan 1, 1989

By N J. Beukes, J Gutzmer, C Reinke, M Bau

In this study the light sparse phase search (SPL_Lt) mode on the Mineral Liberation Analyser (MLA) was successfully used to identify and quantify the abundance of rare earth element (REE) phosphates in Precambrian iron formations. Monazite (light REE phosphate) and xenotime (Y and heavy REE phosphate) are identified and data from the MLA combined with the mineral chemistry of the two minerals are used to calculate and model the expected REE concentration and distribution in these two REE phosphates. The REE phosphates account for up to 31 per cent of the REEs in the banded iron formations (BIFs) and excellent correspondence is observed between the modelled REE patterns and the whole rock geochemical data available for the same samples. Except for quantifying the mineral weights, the sparse phase search also allows for the localisation of REE phosphate grains and the observation of their association with other minerals using backscatter electron (BSE) imaging. These observations are used to conclude that the REE phosphates were most likely of diagenetic origin, with REEs and phosphate remobilised from primary chemical precipitates. It is demonstrated that automated mineralogical techniques can be used to qualitatively and quantitatively describe the influence of a rockÆs trace mineralogy on its geochemistry.

Jan 1, 2008

Faced with low prices and weak demand in an oversupplied market, the Australian coal industry must seek to further reduce its costs. The paper examines minesite competitiveness of the open cut coal industry in Australia with some references to the coal operations of M.I.M. Holdings Limited. The make-up of F.O.R. mine costs is analysed in order to identify where efforts should be directed to maintain competitiveness. The scope for mine site improvements through changes to working practices, the application of new technology and cost management is examined.

Jan 1, 1987

By Burman B. C

This paper describes studies into two particular aspects of the Lochiel deposit which formed part of feasibility level geot2chnical and hydrogeological investigations for proposed open cut mine development. The two aspects were depressurisation of thick beds of silt located through the profile and the determination of characteristics and origins of soil structure and their effect on pit stability. The studies were very detailed and multi disciplinary and highlight the integration of geology, geotechnics, hydrogeology and mining that is required for mine development studies. It is considered that as more marginal deposits are developed throughout the world the demands for efficient economic mining together with in- creasing scales of operation will require simi- lar types of studies. As such the studies pre- sented herein are likely to be a forerunner to a,emerging trend for development of open pit mines in difficult ground and water conditions.

Jan 1, 1986

By D Giles

We present plate tectonic reconstructions, showing that porphyry-type ore deposits are spatially and temporally linked to ridge subduction. A reconstruction of the Peruvian subduction system reveals an immediate metallogenic response to the arrival of the Nazca Ridge at the subduction trench, followed by southward migration of the zone of metallogenic activity due to the lateral migration of the zone of ridge subduction. A similar pattern is recognised in central Chile , where the spatio-temporal distribution of giant ore deposits coincides with the arrival of the Juan Fernandez hotspot chain at the subduction zone. We conclude that there is a spatial and temporal link between ridge subduction and ore deposit formation, with high metal fluxes concentrated in zones of ridge subduction. Thus, the recognition of tectonic patterns associated with ridge subduction can provide insights into predictive mineral discovery by enhancing our ability to predict the position of large mineral deposits in other modern and ancient orogens. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Moxon NT, Torrace AC

The detonation pressure of an explosive is a function of its density and its velocity of detonation (VOD) and relates directly to the degree and manner in which the explosive loads the surrounding rock. The suitabil- ity of an explosive to any particular situation is determined not so much by the total energy released but more by the rate at which it is released. As the science of rock blasting advances it is becoming economically more important to quantify explosive performance, particularly with respect to quality control and fragmentation. As part of a major explosive user, BHP Central Research Laboratories have developed a number of tech- niques to determine the detonation characteristics of explosives. These include a method of continuous velocity of detonation measurement based on the SLIFER principle. This not only enables the VOD of the explo- sive to be determined, but also has the versatility to allow factors such as under priming, slow run up, the effect of water, variable energy load- ing and the velocity of the shock wave in the stemming to be assessed. Multi point VOD systems have also been developed for more routine appli- cations. With a minor modification they can be used to determine the absolute delay of detonators accurately and economically. Direct deto- nation pressure measurement methods have also been developed based on piezoresistive techniques. Future developments include the incorpo- ration of all the above techniques into a single, portable package, allow- ing easy use on the mine site.

Jan 1, 1988

Over the past seven years, a combination of New Zealand-, Australian- and German-led research voyages using the research vessels Tangaroa, Southern Surveyor, and Sonne respectively, have revolutionised our understanding of the Kermadec-Tonga arc-backarc systems. This convergent margin is the most seismically-active subduction zone system on Earth with convergence rates steadily increasing northwards from the Hikurangi Trench to ~250 mm/year at northern Tonga. In combination with the intra-oceanic setting, factors potentially producing magmatic, tectonic, and hydrothermal variability in this system include an increase in potentially subductable sediment northwards along-strike, intersection of the Louisville Ridge (hot-spot chain) and Osbourn Trough (paleo-spreading centre) with the arc at ~25¦S, and the possibility of Samoan (hot-spot) plume ingression in the northern Lau Basin. The bulk of the magmatism is submarine; whereas only a few emergent (some transient) volcanic islands exist, about 80 submarine volcanic centres of significant size (>1000 m above surrounding sea floor) are present between White Island in the south to north of Tafahi in Tonga. About 35 per cent of these centres are hydrothermally active. Important petrogenetic features of the volcanic rocks along this arc system are the abundance of rhyolite (some quartz-amphibole-bearing), and the outcrop of primitive olivine-clinopyroxene-phyric basalts in satellite cones of the major edifices. Many of the edifices consist of complex caldera systems. Eruptions from and degradation of these edifices were probably tsunamigenic. Many of the hydrothermal systems developed within the edifices are likely destroyed during the sector collapses which are the characteristic edifice degradation mode. There are three backarc spreading systems along this margin: the Havre Trough, Valu Fa-Eastern Lau Spreading Centre, and the nascent Fonualei Rifts. The latter are particularly notable in having captured the entire suprasubduction zone magmatic flux for a distance of about 150 km, shutting down the adjacent volcanic front arc volcanoes.

Jan 1, 2005