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By T R. Gibbons, I Grayand

Geotechnically massive strata may lead to a host of problems during longwall mining. These include windblast on initial goaf fall, sudden loadings on powered supports, periodic weightings, fractures that may propagate to surface, and extreme subsidence problems. It is essential to identify these problems prior to mining and to appropriately deal with them. The problem is essentially that the rock mass does not breakup evenly and when it does so it tends to produce large blocks which may suddenly move. The rock types that produce these problems tend to be massive sandstones, massive siltstones and sometimes igneous sills. The fundamental problem with these is that they do not breakup readily. This is because the ratio of stress they are subject to compared to their strength is low. Thus, the shallower mines with lower stresses are more subject to this problem than deep highly stressed ones with similar strength rock.

Nov 29, 2022

This paper attempts to put into perspective the implications of the legal disclosure requirements for promoters and consultants when making statements concerning ore resources and reserves. The need to take account of non-technical as well as technical factors is highlighted.

Jan 1, 1987

The law relating to the Treaty of Waitangi is developing rapidly at present. A number of separate, but related, developments can be identified.

Jan 1, 1988

By Zhijing Z, Huiling Z

The influences on flotabilities of dolomite and magnesite with modifiers and influences on the function of collectors and modifiers with Mg+z Ca+2 were studied. The flotation results of artificial mixed mineral showed that using combined salified water glass and (NaPO3)6 as a modifier for magnesite-dolomite separation can obtain an excellent Selectivity.

Jan 1, 1993

Several coal preparation plants are presently "automated" to the extent of automatic sequencing and interlocking via digital means, together with closed loop control on various level and density circuits. This paper will explore the potential for second generation automation utilizing on-stream ash analysers and other measuring elements so as to optimize the total metallurgical process. This would enable maxim-ization of recovery, improved product homogeneity and minimum reagent consumption.

Jan 1, 1985

Expert systems are a product of Artificial Intelligence (AI), a field of long standing, dedicated to the study of problem solving using heuristics, construction of symbolic representations of knowledge about the world, communications proce

Jan 1, 1998

A paper presenting the results of studies carried out on rotary drill bit life at EluraMine N.S.W.Contributing parameters, including dataon drill operation and geology are compared to the performance observed for the drill bits. Correlation and performance characteristics are presented, relating this data to cutting size distribution over drilling depth.Details are presented of experiencegained through the operation of rotary drillsat Elura.

Jan 1, 1985

By de Brodtkorb MK

Late Cenozoic ore deposits "Precious and base metal-rich" and " Sn-Ag-polymetallic"of Northern Puna are associated either with Middle Miocene dacitic volcanic-dome complexes or with Upper Miocene dacitic-andesitic volcanic centers. Ore mineralogies and their related volcanism are discussed. A strong link is observed between the Cenozoic Metallogenetic Province of Northern Puna and the Southern Bolivia Tin and Polymetallic provinces.

Jan 1, 1995

Evaluation of reserves on a production scale within a shear-hosted gold deposit is complicated by the nature of the mineralisation itself. The 'payable' ground seems to be confined to areas with intense shearing, while the remainder of the deposit is characterised by 'background' mineralisation at a very low level.

Jan 1, 1993

The effect of accurate detonator delay timing on blast results can now be studied with the development of the ICI Electronic Detonator. This detonator has an accuracy and precision orders of magnitude greater than the current range of pyrotechnic delay detonators. A series of field trials have been conducted to quantify the effect of delay accuracy and timing on blast performance. These trials have demon- strated that delay timing can have a marked influence on blast fragmen- tation, muckpile displacement, blast vibration and airblast.

Jan 1, 1989

By Dolan P

Various operating practices have been developed over many years to ensure safe and efficient production from the 1100 orebody. Some of these practices are described.

Jan 1, 1982

By K Uchino, M Inoue

Self-potential anomalies are generated by fluid pressure gradient, by temperature gradient or by chemical gradient. On the basis of this principle, a new technique is proposed to locate the fire source of spontaneous combustion of coal by the self-potential method. In order to investigate whether this method can be applied to locate the spontaneous combustion of coal in practice, surveys of self-potential distributions were undertaken in a coal waste pile undergoing spontaneous combustion. The results showed that there is a negative centre of the electrical potential distribution in the measurement area. The potential in this centre is about 140 mV lower than that in the surrounding area. Moreover, the negative centre of electrical potential distribution almost overlaps with the high temperature zone. Therefore, it is concluded that it is possible to locate the heat source by the measurement of self-potential distribution.

Jan 1, 2005

By F Butler, G E. Batley, A C. Hogan, A R. Butler

The ANZECC/ARMCANZ (2000) Water Quality Guidelines (the Guidelines) are the primary reference used in Australia and New Zealand for managing and regulating water quality. For most mining operations in Queensland, the environmental authority (EA – licence) incorporates the national default guideline values (GVs) for ecosystem protection as trigger levels (TLs). Exceedances of TLs ‘trigger’ further investigation and reporting. A review of the surface water compliance history at a metalliferous mine in North West Queensland identified minor exceedances of the cobalt GV as a common trigger for investigation and compliance reporting.The reliability of GVs is dependent on the availability and quality of ecotoxicology data for the relevant contaminant. The current national default GV for cobalt of 1.4 µg/L is classified as a low reliability GV due to the lack of available data at the time it was derived (ANZECC/ARMCANZ, 2000).The Guidelines are presently being revised and the toxicant GVs will be available as a set of web-based values and associated technical briefs. The new platform will enable the timely revision of existing GVs and inclusion of GVs for additional toxicants. Cobalt was considered a priority toxicant for the Guidelines’ revision, but was not included in the revision process.A preliminary review of the international literature indicated that at least 15 additional chronic cobalt toxicity studies had been published since 2000, sufficient to derive a high reliability cobalt GV using the protocols developed for the revision of the Guidelines (Batley et al, 2014; Warne et al, 2015). This presented an opportunity to improve environmental management by increasing the reliability of the performance measure.CITATION:Hogan, A C, Butler, A R, Butler, F and Batley, G E, 2016. Derivation of high reliability water quality guideline values for cobalt in freshwaters – improving water quality guidelines for better water quality compliance management in mining, in Proceedings Life-of-Mine 2016 Conference , pp 205–208 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By S Maryati

Surface mining activities disturb large areas, produce great sediment loads and tend to be a source of water pollution if they are not managed properly. Coal mining in Indonesia has a very high risk of soil erosion because the coal mining areas are generally located in tropical areas with a high average of rainfall (4000 - 6000 mm/year) and use surface mining methods. The main factors affecting erosion risk are climate, soil type, topography, vegetation cover and management factors. Thus, the monitoring of erosion risk in mining areas is very important due to the characteristics of coal mining in Indonesia. The objective of this research is to determine the ability of satellite images (remote sensing data) and geographic information systems (GIS) to provide an accurate and up to date spatial database for the monitoring of erosion risk in surface coal mining areas using the Universal Soil Loss Equation (USLE) method.The erosion risk analysis and spatial data processing are generated by the ArcGIS 9.3 software and need several data, namely: an erosivity map, erodibility map, a slope map, vegetation index map and land management or land cover map. The erosivity map is derived from the rainfall data, whereas the erodibility map is derived from the soil map. The slope map is derived from the SRTM-DEM (Shuttle Radar Topography Mission-Digital Elevation Model) and processed using 3D analyst tools. Furthermore, the vegetation index map and land cover map are derived from a satellite image using digital image processing techniques.This preliminary study produced results that show soil erosion monitoring, which is integrated with remote sensing and GIS technologies, has great potential for producing accurate, advance, and low cost erosion risk maps in coal mining areas. This map is very important for getting spatial distributions of the erosion and useful for developing erosion management plans.

Nov 22, 2011

Past and present developments in the use of blast furnace slag in the manufacture of glass are outlined. The crude slag from Port Kembla is beneficiated by the Mineral Resources Division of Australian Consolidated Industries Ltd. at Mascot using a dry magnetic separation process which reduces the iron level in the slag to an acceptable value, The chemical and physical properties of both the crude and beneficiated slag are given and compared with those of other slags used in the manufacture of glass. Slag is added to intro- duce alumina into the glass and its addition to the glass batch also results in faster melting and refining. Slag was first used in Australia in 1968 and its use has increased steadily year by year. At present about 16 000 tonnes of slag are used per year, mainly in amber and white glass. Beneficiated slag is used'in three plants to supply all the alumina required in the amber glass and in four plants to supply part of the alumina required in the white glass, the amount added depending on the acceptable iron level in the glass. Slag is also used in limited quantities in the manufacture of both dark and light green glass.

Jan 1, 1979

The detailed work done by Stillwell and Edwards on the occurrence of cobaltite and safilorite-Iollingite at the South Mine, followed by its presentation as a paper to the Institute, calls for, a few notes on its occurrence elsewhere in the Broken Hill field. No massive cobaltite similar to that in the South Mine veinlet is known except from the Consols Mine (as mentioned in the paper). Fine grained cobaltite has, however, been found in low-grade ore from the North Mine. Microscopic grains occur in a mineralized green feldspar pegmatite. The feldspar has been replaced in part by graphite, and the cobaltite occurs in association with the graphite. In its hardness, pinkish-white colour, and resistance to the standard etchingqeagents it is similar to the South Mine cobaltite; it is etched by acid permanganate solution. An interesting feature of this occurrence is the way in- which some of the minerals (notably galena) have forced apart the graphite lamellae in crystallizing, forming lenses enclosed by the curved cleavage surlaces 0;[ the graphite.StillwelI and Edwards cite a note by G. Smitht for the statement that "cobaltite has been recorded from the Australian Broken Hill Consols Lode in the vicinity of the rich silver deposits, though not in contact with them."Smith, however, is here referring to the oxidized zone. Elsewhere in the same article he states "... a deposit of cobaltite in a very much altered condition was found. This was impregnated with silver, and assayed as high as 3,000 ounces," Of the cobaltite in the unoxidized zone, Smith simply states that it became rarer with depth.Cobaltite has also been recognized by Mr. H. F. Whitworth, M.SC., Curator of the Mining Museum, Sydney, in specimens from Burt's Copper Mine eight miles south of Broken Hill.

Jan 1, 1944

By Chapman RL

A new process has been developed to remove the impurities copper, cadmium, cobalt and nickel from a zinc plant electrolyte by cementation on zinc dust. The process has been tested in the laboratory and in a continuously operated pilot plant. It has been found that cadmium, in the presence of small amounts of antimony in solution, assists the removal of cobalt. Cementation is conducted in two stages: the first stage for removal of copper with a small excess of zinc dust to produce a relatively high grade product, the second stage for removal of cadmium, cobalt and nickel by addition of zinc dust in the presence of anti- mony. The excess zinc and the cadmium present in the second stage cementate can be selective- ly recovered by slow leaching in spent electrolyte. Zinc dust processes in use elsewhere are described and compared with the present system for use in the Risdon circuit.

Jan 1, 1984

By Marshall T. E, Finfinger G. L

Gulf Coast domal salt mining operations have had sporadic encounters with methane gas emitted without any warning. In virtually all confirmed cases, the methane was localized in methane enriched zones. In a few cases large quantities of methane were expelled rapidly with salt outbursts, resulting in dangerous methane concentrations. Estimates of methane liberated by face blasts in methane-enriched areas is needed in determining how much air should be supplied to the face for proper dilution. A relationship between the gas content of salt samples collected from the face and the amount of methane liberated would be helpful in estimating how much methane will be produced by a face blast. Little is known about the layering or stratification of methane in large area-low velocity airways. This publication reports on three tests conducted by the Bureau of Mines which monitored the immediate return air of four faces during blasting. The test locations were in a methane gas-enriched section that had previously experienced two large outbursts and many smaller ones. A comparison was made between gas content values of face salt samples from the dissolution test and the gas liberation quantities. The characteristic movements of the methane in a large room with low air velocities were charted. This will help to better understand the factors involved in proper placement of methane sensors as a warning system.

Jan 1, 1988

By J Slade, R Trueman

Unplanned dilution has the potential to seriously undermine the economic viability of a mine, and in some cases results in mine closure. The effect of stress damage on dilution has become increasingly relevant as mining depths increase. In the case of narrow vein mining, the incremental extraction of long-hole rings has the potential to result in a moving high stressed zone at the stope brow. This leads the hanging wall and footwall to experience a spike in the stress to strength ratios as the brow passes. In some cases, the stress to strength ratio may be high enough to result in fracturing or damage to the rock mass. The aim of the study described in this paper was to investigate whether stress damage results in a significant increase in dilution. The study involved analysis of overbreak from 410 case studies from the Kundana Gold mine in Western Australia. Site personnel had already undertaken calibration studies of the stress levels that result in rock mass damage. This calibration, in conjunction with numerical modelling showed that stress damaged stope walls at this mine had on average 50 per cent more overbreak than stope walls where stresses had not exceeded the damage criterion. For a design mining width of 1.5 metres, and with both walls impacted, this represents 36 per cent increase in dilution. After adjustment for possible sources of bias the difference reduced to an average 0.10 metres per stope wall, representing 13 per cent dilution for the mining width under consideration. The potential for stress damage related overbreak should therefore be considered as part of any assessment of narrow vein dilution.

Jan 1, 2005

By T Wettainen, G Shekhar, M Stromsten, B Skawina

The aim of a transportation system in an underground mine is to move the rock masses from one location to another in the most preferable manner by minimising the long and short-term operational costs. A continuous improvement of material transportation systems used in mines generates a need for continuous investigation of the current and new underground transportation systems. In an underground mine, an orepass is a common system used to transfer the material to the lower levels. If this system loses the ability to transport or store the necessary material capacities, it would result in production disturbances. In this paper, discrete event simulation (DES) was utilised to analyse the material inflow and outflow of the orepass systems when subjected to the different conditions. The study presented in this paper is based on the Malmberget mine, the second largest underground sublevel caving (SLC) iron ore operation in the world.

Mar 15, 2021