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Marble deposits of dolomitic variety are available in large quantities in India and for extracting these deposits diamond wire saw cutting machine is mainly used. Cutting performance of the diamond wire saw machine depends on rock parameters, machine parameters and operational parameters. Rock parameters related to physico-mechanical properties, such as, compressive strength, tensile strength, shear strength, modulus of elasticity and abrasion resistance of marble play role in determining cutting rate and beads wear rate. Thus, this study was undertaken to determine the relationship between different physico-mechanical properties and cutting performance. This work also aimed at enhancing the cutting performance of diamond wire saw in dolomitic marble deposit. Study was conducted in the field at three different zones having deposit of soft, medium hard and hard dolomitic marble. During the study, cutting rates and wearing of diamond beads were recorded in the field. Physico-mechanical properties were determined in the laboratory. The results obtained were subsequently evaluated by using statistical analysis. Study revealed that these properties of marble play a significant role in the performance of diamond wire saw machine. Predictive equations for the wearing of diamond beads and cutting rate were developed based on regression models. Results of this study will be of ample use for operators of wire saw to achieve maximum cutting performance and for manufacturers in designing the diamond beads.

Dec 6, 2010

This paper gives an overview of the difficulties associated with determining the strength of hard rock pillars. Although a number of pillar design tools are available, pillar collapses still occur. Recent examples of large scale pillar collapses in South Africa were caused by weak partings which traversed the pillars. Currently two different methods to determine the strength of pillars are used namely, empirical equations derived from the back analyses of failed and stable cases and numerical modelling tools with an appropriate failure criteria. Both techniques have their limitations and additional work is required to obtain a better understanding of pillar strength. Empirical methods are popular and easy to use, but care should be exercise that the results are not extrapolated beyond the range of the data which were used to derive them. An example is the Hedley and Grant formula (derived for the Canadian uranium mines) that has been used for many years in the South African platinum and chrome mines (albeit with some adaptation of the K-value) to design the pillar layouts. Very few collapses have nevertheless been reported and it might even be too conservative an assumption of pillar strength in these mines. As an alternative, some engineers strongly advocate the use of numerical techniques to determine pillar strength. A close examination unfortunately reveals that these techniques also rely on many flawed assumptions. An area where numerical modelling is invaluable, however, is to study specific pillar failure mechanisms, such as the influence of weak partings on pillar strength. In conclusion, it appears that neither empirical techniques nor numerical modelling currently provide a solid basis to conduct pillar design. It is therefore recommended that both these techniques be utilised when confronted with a pillar design to obtain the best possible insight into the problem.

Nov 25, 2010

The importance of the minerals industry to any economy is clearly demonstrable. Its raw materials and products are the foundation of modem society and they have shaped the history of mankind from prehistoric times to the space age of today. However, those in the minerals industry have clearly failed to impress this fact on the consciousness of the public, bureaucrats and politicians. They have also failed to engage their dedicated opponents in a constructive debate. This is mainly because the minerals industry has been unwilling (until recently) to deal with the "soft" issues of civil society, nor understand and operate on a more emotional level. Technical professionals (as well as managers) in the future must be as comfortable in handling community concerns over social, environmental or landowner issues, as they are with logging complex drill core, designing blast patterns and separating one mineral from another. They must become caring, effective communicators and mediators. These are the new skills of a professional in the Third Millennium. These issues are outlined and discussed with some Australian data used to illustrate the point. If there is to be a future for all, then the policy makers within all levels of government (national, regional or local) must not drive essential mineral development offshore. They must address ways to support wealth creation mechanisms, particularly innovation. The minerals industry is a powerful wealth creator for ordinary citizens and an innovator. Politicians and their advisers must not .be allowed to forget this fact. If the ANZAC minerals industries do not win the emotional debate and successfully deal with the "soft" issues as well as they deal with the technical issues, there can be only a dim future ahead.

Jan 1, 2000

Three large deposits of good quality lignite were located and delineated in the Central Otago region between October 1978 and July 1979. The program was initiated and funded by Mines Division of the Ministry of Energy as part of the national Coal Resource Survey. The exploration work was carried out by Lime and Marble Limited on a contract basis (Bowman, 1980). The three deposits were all potentially mineable by open cast methods and possessed combined indicated and, inferred reserves in the order of 1000 x 106 tonnes. They ranked with the previously discovered Eastern Southland 1ignites and as such constituted an important national energy resource. Fifteen months later a second more detailed investigation of similar duration was undertaken by the Liquid Fuels Trust Board (LFTB). The objective was to upgrade and refine the geological data base of all of the nine South Island 1ignite deposits in order to make preliminary economic assessments of their potential. Again Lime and Marble Limited acted as the exploration operator (Bowman, 1981a, 1981b, 1981c).

Jan 1, 1983

ABSTRACTRock stresses can be modified by physicochemical processes.If rock pores allow the ingress of water and oxygen, but are not large enough to permit the exit of larger molecules of weathering products, anomalous rock pressures develop. Rock masses may also be subjected to osmotic pressures developed as water diffuses into pores and joints filled with saline water. Anomalous rock pressures may also develop as gels filling pores undergo syneresis and as salts crystallize from pore solutions.

Jan 1, 1968

By J Belke

Murrin Murrin Operations have not had a successful beginning. Numerous reliability and operability issues, many of which are the result of design decisions, have been addressed through mechanical and operational changes and the CCD circuit is no exception. Four design aspects of the CCD circuit that have caused and continue to cause operational problems are: the inclusion of solution neutralisation gypsum in the CCD circuit feed which was designed solely for HPAL residue without proper investigation of its impact on the achievable underflow density and resulting wash efficiency; the decision to construct the thickener base from thickened solids; the lack of redundancy in the overflow, underflow and tailings pipe work; and the lack of thickener operational flexibility in the central rake-lift and feedwell dilution system. In November 2002, the lack of operational flexibility in the rake-lift and the feedwell dilution system was improved through mechanical modification as follows:CCD1 rake mechanism was modified to allow central vertical lift of 600 mm; and CCD1 changed to forced dilution using the Outokumpu TurbodilRântechnology by replacing the E-DucânRtechnology of Eimco. The installation and the results of the CCD1 rake-lift mechanism and feedwell dilution system changes are discussed in this paper.

Jan 1, 2004

By U König, N Norberg

To cope with varying raw material qualities and increasing prices for energy, a more frequent and accurate monitoring of the processing of iron ore became the focus in sinter plant operations. Traditionally, quality control in iron producing industries has relied on time-consuming wet chemistry or the analysis of the elemental composition. The mineralogy of a sinter that defines the properties and behaviour in the blast furnace is often not frequently monitored. One fast method to analyse the mineralogical composition of iron sinter, raw mixtures and iron ores is X-ray diffraction (XRD). Recently statistical methods such as similarity analysis or partial least square regression (PLSR) in combination with XRD raw data has become more and more popular in handling large amounts of data and correlating process-relevant parameters directly with an XRD measurement. PLSR can be used to correlate process parameters directly from the XRD pattern without investigating the mineral content. Hidden information that is present in the measurement but not determined with traditional methods can be used to improve the characterisation of the analysed materials.CITATION:König, U and Norberg, N, 2017. Iron sinter process control using X-ray diffraction – part : monitoring of low temperature degradation, in Proceedings Iron Ore 2017, pp 75–78 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By J P. Ashby

Compared with elsewhere in the world, New Zealand quarries have tended to be mostly small. The reasons for this are a combination of the relatively high transport costs, low population density and a pioneering, self-employed attitude. The small size of the operations is reflected in low productivity, a tendency to repair and rebuild equipment rather than replace it, designed flexibility in the processing plant, minimal reserves investigation or development planning and a versatile and innovative work force who are generally not professionally trained. The Resource Management Act and the Health, Safety and Employment Act as well as a customer driven demand for higher quality and consistent products will have even greater influence upon future direction of the Industry. The trend will be towards fewer quarries operated by companies and professional managers that can adapt to the new demands.

Jan 1, 1993

By Hirst H, McAfee J

In December, 1934, Mr. R. Sussex extruded some silver lead alloy wires in order to determine their electrical resistance. After the determinations had been made each wire was threaded through a sheet of paper on which the composition was noted. The wires were placed in a more or less tangled mass in a cupboard in March, 1935. It was not until September, 1936, that they were re-examined, and it was found that during the eighteen months some of the wires had corroded very badly. It was not until March, 1938, that the wires and the corrosion product could be examined, and the results are given in the following pages. It is of interest to note that none of the numerous silver-lead alloys which have been used for creep testing in the rolled condition have shown a similarphenomenon. The silver content of the rolled alloys was, however, never greater than 0·1%.GENERAL APPEARANCE OF THE CORRODED WIRESThe wires contained 0·1% up to 28% of silver, and a general examination showed that the corrosion had progressed farther the higher the silver content. This can be seen in Fig. 1, which is a photograph taken in March, 1938, of typical wires at a 'magnification of five diameters. In the early stages the corrosive action seems to be localized and an area of grey, yellow or reddish brown powder appears. The grey corrosion product is by far the one, most frequently seen, and in the later stages the only one visible from the outside. The reddish coloured product is sometimes seen on the residual metallic centre when the grey product has been broken away.The irregular extent of the corrosion can be seen in Fig. 2, which shows (natural size) the 5% silver wire after standing two years. The corroded parts are seen to be much thicker than the slightly corroded ones. The corrosion product, being non-metallic, is quite brittle and falls away from the wire on bending. In the extreme case the' whole wire has corroded and presents a cracked appearance as seen in Fig. 1 (281% silver).An approximate idea of the extent of corrosion can be obtained by measuring the diameter of the corroded part. The original diameter in each case was ·050/ ·051 inches and in Table I are given the diameters of the corroded parts after Hand 3 years respectively. When the diameter...

Jan 1, 1941

Surface subsidence caused by coal mining operations was the subject of a very successful symposium organised by the Illawarra Branch of The Australasian Institute of Mining and Metallurgy in February, 1973. This symposium dealt with the principles of subsidence and overseas experiences arising out of underground mining. Since that time the New South Wales Department of Mineral Resources and Development (formerly the Department of Mines) has incorporated in the approval for pillar extraction certain conditions related to the monitoring of surface movement. Surveys and plans are required to be kept at mines where total or partial extraction of coal takes place. This paper traces the monitoring of surface movement in the Northern Coalfields of New South Wales over the past ten years. Reference is made to the National Coal Board's Subsidence Engineers' Handbook (1975) and how the guidelines expressed therein have been beneficial. Mining engineers in Australia are able to plan underground workings where minimum subsidence is allowable and are in a position to foreshadow the surface effects where total pillar extraction is carried out. In certain cases such surface effects can be minimised by structural design in buildings or pipelines.

Jan 1, 1980

By S F. Simmons

The Ohaaki Rhyolite and the Rautiwiri Breccia are two volcanic units occurring in the shallow and deep parts of the Broadlands-Ohaaki geothermal system. Alteration of these units by chloride waters results in distinct mineral assemblages that also have distinct whole rock compositions. The Ohaaki rhyolite is altered to an assemblage dominated by quartz, adularia, illite and pyrite as a consequence of silica, potassium and sulfur metasomatism. Locally, these rocks contain up to 0.5 ppm Au. The Rautiwiri Breccia by contrast is altered to an assemblage dominated by albite, adularia, quartz, illite, chlorite and pyrite in association with modest sodium metasomatism. Whole rock oxygen isotope compositions of altered rocks range between 3.3 and 7.5 ë, and are generally lower compared to their fresh rock equivalents having values of 9.5 to 10.6 ë; the result is broad pattern of lower values with increasing alteration intensity.

Jan 1, 2002

Mineral Changes that Occur During Coal Gasification

Sep 13, 2010

By P M. Outhwaite

Everyone present today is especially aware of the need for minerals in this society of ours. The words 'especially aware' were deliberately chosen because this is a meeting of the NZ Branch of The Australasian Institute of Mining and Metallurgy not a dilettante group such as some of our critics. Members of the Australasian Institute of Mining and Metallurgy knew that our great farming industry, our shelter, our transport and our energy supply, are largely dependent on a flow of minerals into this country despite the presence of large coal and natural gas reserves. Flow in was said because New Zealand imports most of its mineral requirements with all the consequential strategic and economic disadvantages. If the above statements are accepted by this gathering it would be a premise fairly stated that New Zealand has a great need to discover and develop minerals.

Jan 1, 1976

The Framework Convention on Climate Change (FCCC) places serious obligations on New Zealand as a signatory nation. This paper examines the nature of the FCCC, New Zealand 's proposed policy response, and the.implications for the minerals industry.

Jan 1, 1994

By Grynberg H, Lindon P, Wardrop J

The Gippsland Basin is unique in Australia in that it is a major resource based industry centre within a sensitive and special environmental context supplying Melbourne, a major urban/industrial environment with most of its energy 'on-line'. The environmental effects of the supply systems are generally local and mostly affect only those who are directly or indirectly dependent on the upstream systems. The major urban metropolis which is served remains largely unaware of the environmental impacts of the system upon which it is dependent, except when specific attention is drawn to them as in the case of the Latrobe Valley Outfall, algal blooms in the Gippsland Lakes, etc. This paper discusses the environmental context within which the energy industries operate, the environmental legislative framework which applies, the likely environmental impacts and some solutions. The energy resources of the Gippsland Basin occur in an area where the physical environment exhibits a wide variety of inherent energy states in its physical and biological regimes. The off-shore regions of the oil and gas platforms has to be able to withstand the wind and wave energy generated in a shallow sea in a confined waterway lying athwart the main current and climatic stream. The coastline includes the delicately balanced quiescent environments of Corner Inlet with its 'wilderness' tourism industry and the powerful surf and long shore drift and dunes of Ninety Mile Beach.

Jan 1, 1992

By B K. Hebblewhite, F T. Suorineni, J D. Tibbett

Block caving is an underground mining method that can provide high production capacities at low operating costs. This enables the profitable extraction of massive, low-grade orebodies and attracts industry towards the method. Block caving operations require significant initial capital investment and predictable cave propagation is crucial to safety and economic success. Lack of access to observe the caving process hinders our ability to learn how the rock mass and geological structures are reacting to mining. Virtual reality scientific visualisation (VRSV) enables the integration and investigation of multiple, large caving data sets and provides a viable alternative to visualise rock mass response without physical access to the cave. Point instrumentation is incapable of providing an overview of cave performance and seismic monitoring, while providing an overview of the rock mass and the response of structures to caving, is only useful when linked to the caving activities. The integration of point instrumentation data with seismic monitoring information, coupled with scientific visualisation of the mining system in a virtual reality environment, provides a powerful means for understanding caving performance.This paper describes the use of a VRSV module at UNSW Australia, designed for investigating the block cave mining system from a case study operation. This module has been used to investigate the location and chronological evolution of seismicity to understand sources of damage resulting in seismic space-time sequences (SSTS) in the caving system. The events within an SSTS represent damage that is spatially and temporally related. An SSTS group represents a collection of microseismic events from a reasonably competent region of the rock mass that has experienced a stress change significant enough to cause sequential damage. SSTS group locations have been seen to be the path of subsequent cave propagation. Thus, SSTS analysis enables insight to further our understanding of rock mass damage in caving geomechanics through analysis of historic data. Such insight has operational potential to learn from recent rock mass activity for optimising the management of undercut advance, draw front advance and cave draw patterns.CITATION:Tibbett, J D, Suorineni, F T and Hebblewhite, B K, 2016. Understanding damage source mechanisms in a caving system using virtual reality scientific visualisation, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 439–452 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By H Thanasekaran, L Christodoulou, J Kohmuench

"Column flotation has been successfully applied to iron ore concentration since the 1980s with the goal of reducing silica content and allowing for the efficient production of pellet feed. Since then, columns have been widely used in iron ore processing due to: their lower capital and operational costs when compared to conventional cells their ability to generate higher concentrate grades and recoveries.Currently, more than 100 columns have been installed within Brazilian iron ore processing circuits for rougher, cleaner and scavenger duties. Despite it being a well-established approach, several technological advances have improved column design, accessories and performance. This work presents the performance of some iron ore columns in Brazil and the recent technological developments.CITATION:Thanasekaran, H, Kohmuench, J and Christodoulou, L, 2013. Column flotation of iron ore - status and advances, in Proceedings Iron Ore 2013, pp 479-484 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 12, 2013

A comparison is made between elementary block estimation techniques and the optimal methods of geostatistics using data from an Australian deposit. Considerable improvement in the estimates are obtained by using the optimal technique in this case.

Jan 1, 1975

THE following brief paper is submitted with a view to encouraging the exploitation of hitherto neglected 10w~ grade ore-bodies which are suitable for extraction by open-cut methods.The Corinthian North mine, situated 10 miles from Southern Cross, in the Yilgarn district of Western Australia, furnishes an example of low working costs, although operations are carried out on quite a limited scale.The body of quartz which is now being worked strikes N.W. and S.E., has a very slight underlie to the west, and lies between bodies of quartz-hrematite s,chist on the east and amphibolite on the west.So far as the property has been explored, it would appear that the underlying sulphide rises to within about 70 ft. of the surface in the northern end of the workings, and pitches away to the south at a grade...

Jan 1, 1915

By Conochie D. S, Grave N. C

Disposable-tip emf cells at present used in liquid steel can be used to measure the state of oxidation of high-iron slags produced in non-ferrous smelting. This provides a new tool for the control and evaluation of pyrometallurgical operations.An investigation of oxygen potential variations throughout a typical nickel smelter using the flash smelting technique gave a valuable insight into the process. Correlations of oxygen potential with ferric to ferrous oxide ratio and nickel content in slag were in reasonable accord with equilibrium data in the literature indicating that the probes may be used both as a plant investigation tool and possibly as a means of obtaining thermodynamic data for slags.

Jan 1, 1979