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By S Slusarczyk, Z Kozlowski

Vibration of surface caused by seismic quakes can make a risk to great mining costruction. We have to do with this risk in the Belchatow open cut mine where seismic quakes of various energy and range have occured since the end of 1970s. The seismic risk influence on the mine structure with the special attention to the slopes of an internal dump has been presented. Hydrogeological and geotechnical conditions of the lignite mining and internal dumping of overburden and ash from Belchatow power plant have been considered. Seismic activity in Belchatow open cut from 1979 to 2001 was described and the connection between mine working and seismicity of this area was investigated. The energy and approximate location of the quakes and seismological parameters of the strongest ones observed from 1995 to 2001 were presented. The mechanism of the quake focuses was determined by means of the primary-arriving wave method. Stability of the slopes was evaluated by means of the Fellenius method. It has been found that seismic events occured in Belchatow region may cause only local eboulements whereas there are not any safety risks to the stability of slopes of the internal dump in Belchatow open cut.

Jan 1, 2003

The coking coal produced by Utah Development Company in the Bowen Basin is processed by a dual system of dense media cyclones for the 30mm x 0.5mm feed and flotation for 0.5 x 0mm material. The basic metallurgy of these processes will be presented with emphasis on the operational characteristics which are peculiar to coal. Potential areas for process improvement by the application of more sophisticated control systems will also be discussed.

Jan 1, 1978

The Permian coal in the Muja Coal Measures of Collie Basin of Western Australia has a subdued lustre because of the fine laminations of lithotypes, and the dominance of dull and dull banded lithotypes with minor bright, bright banded and fusinous types. The maceral composition of the coal is variable, however the macerals of vitrinite and inertinite groups dominate and the exinite and mineral matter contents are low. The lithotypes have low concentrations of trace elements and the boron concentration is between 10 - 100 ppm recorded only from the dull lithotypes. On the basis of organic petrology, the inter-seam sediments, flora and the very low concentration of boron, the depositional environment postulated for the coal is braided, fluvial and fluvio-lacustrine with marked fluctuations in the water table. The low water table in the environment accounts for fusain and inertodetrinite in the coal.

Jan 1, 1996

By Anderson KG

Multi-seam mining under the western portion of Lake Macquarie NSW commenced in 1982. Up to three seams separated by partings ranging from 10 to 30 metres are mined simultaneously by Newcom Collieries. A feature of these workings is the minimal bedrock cover, which ranges from 130 metres down to only 40 metres. "Surface" subsidence control has an over-riding influence on the design of the workings. Subsidence considerations govern both the selection of the mining method and the dimensioning of the workings. To date, workings have been designed in accordance with the "Wardell Guidelines for Mining Under Tidal Waters". These guidelines are tabulated and evaluated in the light of advances in rock mechanics knowledge and local subsidence data collected since the Guidelines were formulated in 1974. The local and regional stability of shallow workings designed according to the Guidelines is evaluated.

Jan 1, 1986

By Raymond G. F

Geostatistics - a tool used by geologists and mine planning engineers to estimate grades and rapidly evaluate alternative mining strategies has reached an advanced stage of development for the silver-lead-zinc orebodies at Isa and Hilton Mines. Geostatistics has been used for over a decade in the massive copper orebodies but the stratiform lead-zinc orebodies are much more complex and provided a completely different set of challenges. Recent increases in computer processing speed and power provided by the Integrated Mine Planning System (IMPS) has aided the development of the geostatistics package. Also the formation of a project team and the subsequent in-house development which has drawn together the expertise of geologists, engineers and system analysts has contributed significantly to the success of the project.The most important feature of any approach to modelling the lead-zinc orebodies is that the kriging search must consider estimate and sample points according to their positions relative to bedding surfaces. By transforming co-ordinates as perpendicular offsets from a plane representing the local strike and dip, it is possible to elongate the ellipsoidal influence to parallel bedding. By interactively modelling surfaces using CAD facilities and then specifying these surfaces as 'hard' or 'soft' boundaries, the geologist has complete control over the kriging process.

Jan 1, 1993

By N Kusuma

Recoverable copper and gold estimates for resource models and ore control routing decisions at Batu Hijau were initially based on flotation testwork from several commercial laboratories. Due to the greater number of copper and gold assay grade available, regression relationships were developed between assay grades and flotation recoveries. Other recovery controlling variables such as oxidation and lithology were included to improve the regression models. With additional drilling, more flotation work was carried out and the regression models were revised to include the new flotation data, also alteration classification and in situ pH. The regression models were replaced in favour of spatially derived models for ore control and short range mine planning. To harness local variability in the block model, blast hole flotation testing is carried out in unison with routine grade assaying. Recovery data are processed (kriged) simultaneously with grade assay data prior to ore polygon delineation. Short range mine planning utilises this model in conjunction with a spatial recovery model derived from drill core flotation data. Long range mine planning utilises the æhybridÆ recovery model whereby the globally robust regression recovery models are overprinted by a spatial (kriged) recovery estimate where flotation data density is adequate (Phase II reserve).

Jan 1, 2002

A numerical method for discriminating between replacement and sedimentary processes is applied to a folded stratiform sulphide occurrence. It is shown that numerical treatment of chemical analyses from a single diamond drill hole allowed a rapid assignment of the ore to the syngenetic sedimentary class and thereby enabled a revision of the evaluation program concerned with consequent reduction in costs.

Jan 1, 1973

The Maddingley brown coal seam at Bacchus Marsh, where mined and bored, tends on the whole to a higher content of volatile matter than the Latrobe Valley brown coals, and this masks the presence of lignitic or earthy coal bands in the bore core analyses. Visits to the Lucifer Open Cut, at Bacchus Marsh, during 1948, revealed, however, a banded condition in the coal seam, as shown in Fig. 1. This banding showed in a face that had been exposed for a considerable period of time, permitting partial drying out and oxidation of the surface coal. The bands consist of different coal types, ,comparable with those found in the Yallournand Latrobe brown coal seams(l).The' light coloured bands in Fig. 1 consist of a buff to light-brown earthy coal of low specific gravity, that closely resembles the pollen coal, that occurs, as similar thin bands in the Yallourn and Latrobe seams. The 40 ft. of coal above the uppermost of these light coloured bands dries out on exposure to a black, closely cracked surface, composed of small dice-like fragments of a lustrous vitrain-like substance, and in every respect resembles the lignitic coal bands of the Yallourn and Latrobe seams.The coal between and below the light-coloured bands develops fewer and more widely spaced shrinkage cracks on drying out, and remains brown in colour and earthy in appearance, resembling the earthy coal of the Yallourn and Latrobe seams.Representative samples were cut of these coals, taking care to exclude surface coal, and analyses were made of them by the Metropolitan Gas Company, through the kindness of Dr. R. S. Andrews, Chief Chemist to the Company...

Jan 1, 1948

By K H. Esbensen

During the next five years Denmark will implement a significant reduction in the national CO2 emissions to fulfil the Kyoto Protocol. The energy sector is central for achieving this goal and extensive use of renewable energy is the most important single factor contributing to reduce emissions of greenhouse gases. DenmarkÆs renewable energy sources comprise wind energy and biomass. Wood chips and straw are the dominant type of biomass in Denmark. More than 500 000 tons of wood chips are used annually, currently with rapidly growth prospects. This contribution focuses on sampling of wood chips.

Jan 1, 2005

Shaft sinking through an amphibolite-granite rock mass experienced rock bursts on the shaft walls and benches. However, rock burst phenomena was exhibited only in granite, which is e1asto-brittle with ability to store strain energy caused by orogenic and man made stresses. To improve ground conditions, blasting of destressing holes at shaft corners was carried out. By this technique rock burst during shaft sinking was minimized, but not eliminated.

Jan 1, 1982

By B Siddall, A Gunstone

The use of a partial secondary crushing circuit provides a flexible way to optimise existing SAG comminution circuits limited by rock competency or enables optimal processing of an ore through second hand equipment not specifically selected for that ore. This paper details the process involved in designing a partial secondary crushing circuit using the recent installation at Mt Rawdon Gold Mine in Queensland as an example.

Jan 1, 2004

By Barnes E. L S

With the introduction of diesel powered loading and hauling equipment, a number of Australian mines producing less than one million tonnes per year from shallow orebodies have been dev- eloped by decline. This method of entry has the advantage of providing both flexible access and early prod uction. However, as the depth of mining increases so does the operating cost of haulage, due to the need for more trucks. This cost, together with increased capital requirements for both equipment and infrastructure, leads to the point where the alternat- ive of shaft hoisting must be con- sidered. With an established decline it is possible to provide an ore hoisting shaft using a drilled raise with subsequent stripping to a suitable size. Using DCF techniques and known equipment operating and capital costs, an economic comparison of the two systems is made to determine the limit- ing depth to which truck haulage can be used.

Jan 1, 1973

By S Smith

Several styles of copper (Cu) mineralisation are present at Sepon. Large tonnage, low grade skarn and carbonate replacement massive sulfide mineralisation occur within the metamorphic aureole of Permian-aged rhyodacite porphyry intrusions (RDPs). During exhumation and supergene weathering, this primary mineralisation has been upgraded to form high-grade chalcocite enriched zones up to 50 m thick, which comprises the bulk of Cu resources currently being mined at Sepon. Groundwaters remobilise Cu to form exotic accumulations of malachite that are locally hosted in irregular karsts in carbonate rocks, found up to 1000 m from source mineralisation. Khanong is the largest Cu deposit and recent discoveries have been made at Thengkham South, Thengkham North and Phabing. All deposits have formed by similar processes of mineralisation. However, all differ due to local variations in host rock lithology, structural setting, and hydrological conditions. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By J Maxlow, M J. Woods, M P. Sandy

The Newcrest Mining Limited Telfer operation comprises both open pit and underground operations producing gold and copper. The underground operation is made up of three production areas, the sublevel cave (SLC), M Reefs narrow vein open stoping and Western longhole open stoping areas. With stoping situated on the abutments of a mature and active sublevel cave, the interaction between mining areas is often complex. This is particularly evident in the M Reefs orebodies with high levels of extraction in all four reefs, and reliance on pillars to maintain local and global stability. A key concern was the potential for a cascading pillar failure to develop and rapidly progress through the M Reefs stoping area. The monitoring plan needed to capture any change in overall stability and identify if deformation was caused by pillar failure within the M Reefs and hanging wall closure, or shear on the reefs caused by SLC influence.

Nov 29, 2022

By B G. Lottermoser

The placement of sulfidic waste below the groundwater table ensures limited interaction with the hydrosphere and suppression of sulfide oxidation. However, if sulfidic waste is placed above the groundwater table and remains uncovered, the backfill becomes part of the unsaturated zone and is exposed to atmospheric oxygen and leaching. This study aims to establish the leaching behaviour of sulfidic waste placed above the groundwater table and the impact of such leachate on the local aquifer at the Thalanga base metal mine. Mining of the Thalanga copper-lead-zinc deposit resulted in a large final mining void (600 m + 150 m + 70 m) and extensive underground workings. The underground workings were partly filled with tailings and the open pit was partly backfilled with acid producing sulfidic waste rock. In addition, the pit serves as a sink for acidic run-off from adjacent waste rock piles and mine workings. To date, the backfill of sulfidic waste rock placed into the pit has not been capped with benign materials and for most of the dry season, the surface of the backfill is covered by melanterite-type efflorescences. Results of kinetic column leach experiments conducted on the sulfidic waste indicate that Cd, Cu, Zn and SO4 rich waters migrate from the backfilled sulfidic waste into the local unconfined aquifer. However, the seepage of alkaline (pH 7.3 - 8.0), high conductivity (>10 000 ¦S/cm) tailings waters into the remaining pit void clearly shows that the acid leachate originating from the sulfidic waste rock does not impact beyond the waste repository and its immediate environment. Geochemical modelling implies that minimal or no mixing occurs between the acid waste rock leachate and the alkaline tailings waters.

Jan 1, 2003

By Fletcher A. E W

Ever since it made its debut in 1962, in the form of a Robbins 31R, the raiseborer has become an accepted tool in the mining and civil construction industries. The first raiseborer to be used in the Witwatersrand goldfields made its appearance in 1968. This was a Robbins 42R which could raisebore 185m deep holes to 1,22m diameter. From 1968 to 1973 capability increased with the introduction of first the 61R, then the 71R and finally the 83R, which could raisebore 610m deep holes to 3,66m diameter. This created a demand for larger holes but the cost of bigger, more powerful machines requiring larger, stronger drill pipe, cutters and other accessories was prohibitive. To avoid replacing existing models such as the 71R, and in order to increase their capability, the concept of reaming in two stages sequentially was developed jointly by a German drilling equipment manufacturer, Wirth, their South African subsidiary, Transbor, and a local contractor, Rocbor Raiseboring and Mining Contractors. The result, the Sequential Reaming Head, proved most successful and existing machines, normally limited to 2,44m diameter holes, could now ream to 3,66m diameter. This created a demand for even larger holes. In order to maximise the use of the sequential reaming head to meet this demand the HG330, and subsequently the HG330SP raiseborer were developed. Using a 4,26m/6,02m cutting head, these machines have raisebored holes 1000m deep in hard rock. The raise- boring of the first major hole to be excavated by this combination, the 484m deep x 6,02m diameter surface shaft at Premier Mine is described. Reference is also made to six other shafts which have been completed or are under construction.

Jan 1, 1987

By Orr T. O H, Hodkinson I. P

The Mount Leyshon breccia complex is located on an east-west trending contact between Cambrian metasediments (Puddler Creek Formation) and the Ordovician Mt. Leyshon granite, within the Lolworth-Ravenswood block. Detailed mapping of basement, breccia and igneous unit geometries, crosscutting relationships and resolution of complex chronological relation- ships indicates that the Mt. Leyshon breccia complex should be reinterpreted as a number of intrusive igneous and breccia phases. This is in contrast to a previously published account of a largely extrusive geological setting. A complex structural history dominated by strike-slip faulting is preserved within the basement units and is responsible for controlling the location and geometry of the breccia complex. The breccia complex has been divided into brecciated "basement", "main pipe breccia" and an "interactive magma/breccia sequence". Main pipe breccia (the most voluminous unit within the complex) has been re-interpreted as an intrusive breccia, rather than an extrusive or vent fill as previously proposed. This is based on the following evidence: 1. the facies characteristics of the main pipe breccia, 2. the presence of a progression from cohesive basement through to mixed breccia, 3. minor basement block rotation during breccia complex formation, and 4. the partial structural control on the main pipe breccia. No unambiguous evidence exists for pyroclastic facies, although the fine breccia variant commonly contains "accretionary structures", very similar in appearance to those formed during pyroclastic processes. In view of 1. above, they are interpreted to be the product of particle accretion during upward movement of fragmental material, although an origin due to altera- tion cannot be completely discounted. heir occurrence in the main pipe breccia indicates that their presence within a rock unit is not necessarily diagnostic of nvroclastic nroeesses.

Jan 1, 1991

By Mallett CW, Hammond RL

Geological maps of the Pacific Rim recently published by the Circum-Pacific Council for Energy and Mineral Resources have provided a useful perspective from which to view modern plate interaction and the evolution of modern fold belts. An important lesson from any study of modern plate interaction is that of the normality of change. The chaotic is more usual than the simple. Present day convergent margins with mixed characteristics are measures of this chaos. Indeed, the character of less than one third of the present length of the Pacific Rim can be ascribed to conventional models of plate interaction. Another lesson is that of the great mobility of oceanic crust. Enormous areas of the Pacific may not be represented in future fold belts developed at convergent boundaries unless normal consumption processes are disrupted, and even then only by linear zones a few kilometres wide. The axes of divergent boundaries creating Pacific Ocean crust have been equally mobile, with new spreading sites taking over from older sites through time. Divergent boundaries, whether active or inactive, consist of oceanic crust, and may be wholly consumed at collision sites with convergent boundaries. Their only potential contributions to fold belt evolution are transforms and magmatic activity. It is this transform component that can provide us with a mechanism to explain the apparent contradiction of both compressional and extensional features occurring together in a developing fold belt. Reconstructions for the SW Pacific are used to demonstrate that the fold belts under construction during the last 4% (Jurassic- Recent) of geologic time have involved interaction between convergent, divergent, and transform boundaries. In the last 15% of earth history (Late Proterozoic-Recent), many enigmatic features of the geologic landscape in Eastern

Jan 1, 1987

Recent exploratory work has greatly enlarged our knowledge of the geology of the sedimentary basins of Western Australia. The most pros-pective of these for oil explorati on are believed to be the Canning, Carnarvon, 'and Perth Basins.The search for oil. in, the Canning Basin has fora the most part been concentrated in" the western part, where four main structural units are now recognized - the Lennard Shelf, Fitzroy Trough, Jurgurra Terrace, and-South Cariizin.g Basin. Of these the Leonard Shelf may. be the'most prospective. The principal objective on the Shelf is the Devonian sequence, which in-cludes well'developed reef complexes. The Lower Carboniferous is regarded., as a further objective, as it contained small quantities of oil in theMeda No. I well.In the. Carnarvon Basin most explorati on has been conducted in the coastal belt of'Tertiary folding, especially in the Cape Range-Rough Range area. -The discovery of oil in the first test well. drilled.in the-basin - Rough Range no. 1 - raised great hopes, for the quick discovery of a ecmuercial field. However the other wells on Rough Range have been dry, and no discoveries have-been made in the-wells drilled on other anticlines.in the basin.

Jan 1, 1962

By Thomas E. G

In the economic evaluation of any Australian mining project, changes in taxation can significantly affect viability. Australian tax laws, particularly in the period since early 1973, have undergone many changes which have led to shifts in the profitability of mining companies. This paper examines the sensitivity of a selected, broadly based sample of Australian mining companies to the changes that have occurred, or are reasonably likely to occur, in taxation legislation. In the past, tax systems have been altered for a variety of reasons, such as 1. reduction'in the impact of inflation 2. neutralization of incidence between different sections of the economy 3. as an incentive to encourage expansion and growth in a particular industry or area, and 4. increase in the real "take" of government. In this paper, conventional rate of return analyses are applied in a study of how profitability is affected under various taxation systems.

Jan 1, 1977