Search Documents

By Georgi H, Farquhar J. W, Lorrigan A. N

The potential for major new lenses of Volcanic Hosted Massive Sulphide (VHMS) beneath the existing Rosebery Deposit is extremely high. Recent deep drill hole intersections of massive sulphides, including 22 in true thickness at 24 per cent Zn, may significantly extend the life of the Rosebery Mine. The Rosebery Ore Deposit is located within Australia's most prospective VHMS mining district, the Mount Read Volcanic (MRV) arc of western Tasmania (Figure 1). The MRVs are a 10 - 15 krn wide arcuate belt of lavas, related intrusives and volcaniclastics. Rosebery is a major Cambrian volcanic hosted Zn-Pb-Cu-Ag-Au rich deposit which has been over-printed by Devonian deformation and granitoid alteration resulting in local rcmobilisation of the ore. The Rosebery Mine Sequence is composed of an east dipping and east facing, predominately felsic sequence of rhyo-dacitic volcaniclastics, epiclastics, sediments and shale lenses more than 500 in thick. This sequence is bounded by two, low angle (35 - 40¦), east dipping thrust faults, the Rosebery Fault to the west and the Mount Black Fault to the cast. The Rosebery Mine lithologies are summarised in the following table: Hangingwall (HW) Polymictic, quartz, feldspar-phyric epiclastics. Black Slates Graphitic, pyritic mudstones. Host Rocks Turbiditic mudstones and sandstones. Footwall (FW) Feldspar-phyric, pumiceous, mass-flow breccias. Cambrian, quartz-feldspar, porphyritic sills intrude this sequence at all levels. Thin, Jurassic, dolerite dykes also occur throughout the mine. Widespread quartz, sericite and chlorite alteration occurs in the FW. This alteration is manifested as quartz-augen schists beneath the orebody. The Host Rocks are pervasively altered with silica, sericite, chlorite and pyrite. Intense carbonate alteration occurs within the orebody, whereas chlorite and pyrite alteration is commonly concentrated directly beneath it. Cambrian volcanogenic alteration is over-printed by three major Devonian, granite-derived, assemblages. These are massive to quartz veined tourmaline, pyrrhotite-pyrite and magnetite-chalcopyrite. Though the Devonian granite has not been intersected in deep drill holes or in mine workings, there is good evidence that it exists within a kilometre of the deposit. The Rosebery orebody is structurally complex when compared to many other VHMS deposits. Evidence for Cambrian growth faulting has been found at the North End of the mine (B lens) where displacement of ore lenses occurs without corresponding displacement of the overlying Black Slates. A well defined cleavage exists throughout the mine, dipping at 28 to 50¦E. East dipping shear zones are also obvious in all parts of the mine workings and reverse movement is evident on many of these.

Jan 1, 1993

THE Great Fitzroy Mines Limited, comprising an area of 183 acres, and held under lease, are situated at Mt. Chalmers, within the Cawarral goldfield, 18 miles from the city of Rockhampton, Queensland, on the Rockhampton-Yeppoon railway.The nearest railway station i; Mt. Ohalmers, distant about half a mile from the mine, with which it is connected by a fairly good road. The outcrop of the ore-body consists almost entirely of ironstained quartzite, no sign of copper being visible. The outcrop and its immediate vicinity have been worked intermittently for gold during the past :fifty years, the ore being amenable to battery treatment.About twenty years ago a company was formed to prospect this outcrop, and work was commenced by driving an adit, but the results proved disappointing, and work ceased. Later a party of prospectors sunk a winze from the adit level, which has sincedeveloped into wh~t is now known as the North shaft. The property was afterwards prospected by Messrs. Oharley and Osborne, who continued sinking the winze, meeting with sulphides at a depth of about 120 ft.The Mt. Chalmers Copper Mining Company was formed to work the property, and smelting operations started on a small scale. These, however, met with ip.different success, and the property was again abandoned.

Jan 1, 1911

By Mouritz M

Ventilation characteristics and the occurrence of nocturnal surface inversions have been investigated within the Mount Whaleback open cut iron ore mine at Newman in Western Australia. When winds are light and/or nocturnal surface inversions form within the pit, episodes of atmospheric stagnation can occur with resultant accumulation of dust, diesel exhaust fumes, and sulphur dioxide evolved from spontaneous combustion of pyritic shale. Nocturnal surface inversions were recorded outside the mine on more than two-thirds of nights. Inside the pit, inversions were much less frequent - occurring on roughly 20% of nights when they were observed outside - and much weaker - the maximum temperature difference being 5 C¦ over 210 m inside the pit compared with 15 C¦ over 150 m outside.

Jan 1, 1988

By P W Haines

The McArthur, Balma (new name) and Habgood Groups are thick (up to 4.5 km) correlative sequences of shallow water evaporitic carbonates, mudstones and sandstones that are exposed largely within the Batten, and southern and northern Walker Fault Zones (Batten and Walker Troughs) of the McArthur Basin respectively. Recent re-mapping of the Walker Fault Zone has provided data for refined stratigraphic correlations between these groups. Two significant hiatuses are now recognised within the Balma Group (base of Vaughton Siltstone and base of Yarrawirrie Formation) and these may represent tectonically-generated sequence boundaries which may correlate with similar local hiatuses within the McArthur Group such as at the base of the Teena Dolomite and Lynott Formation respectively.

Jan 1, 1994

By Wyborn L, Giddings J. W, Plumb K. A

The McArthur, Balma (new name) and Habgood Groups are thick (up to 4.5 km) correlative sequences of shallow water evaporitic carbonates, mudstones and sandstones that are exposed largely within the Batten, and southern and northern Walker Fault Zones (Batten and Walker Troughs) of the McArthur Basin respectively. Recent re-mapping of the Walker Fault Zone has provided data for refined stratigraphic correlations between these groups. Two significant hiatuses are now recognised within the Balma Group (base of Vaughton Siltstone and base of Yarrawirrie Formation) and these may represent tectonically-generated sequence boundaries which may correlate with similar local hiatuses within the McArthur Group such as at the base of the Teena Dolomite and Lynott Formation respectively.

Jan 1, 1994

By Bowdler RJ, Lowson RT, Sarbutt JV

There have been few long-term studies of sulphide oxidation under controlled conditions. The object of this study was to investigate the oxidation and leaching characteristics of pyritic mine material under conditions that were commensurate with field conditions but which could be controlled and monitored on a long term basis. The test material - overburden from Woodlawn Mines Pty Ltd - was packed into a 300 cm high column and leached with water at an infiltration rate of 256 mm y-1 for 5 years. Chemical conditions within the column were continuously monitored by sensors embedded in the overburden and leachate from the base of the column was analysed weekly. The study examined the relationships between heavy metal release and gas, moisture, and chemical conditions in the column.

Jan 1, 1988

By B Banerjee, N Kumar, S Parihar

Rampura Agucha Pb-Zn Mine (RAM) is located about 200 km to the south-west of Jaipur in the state of Rajasthan, India. Open pit mining operations commenced in 1988 and continued to 2018. RAM open pit footprint is the largest in India with length of 2000 m, width 1500 m and depth of 400 m. Development of an underground mine under the operating pit commenced in 2013, through trial mining longhole open stoping with cemented backfill was established as a preferred mining method. Nine years in operations underground mine has reached the production capacity of 4.5 MT, which represent more than 70 per cent of the ore volume mined by the pit. RAM is currently the world second largest underground Pb-Zn mine.

Nov 29, 2022

By Hare G

The emphasis in Australia, until recently, has been on large scale mining methods with drive sizes in excess of 4.5 metres square and the acceptance of high dilution ratios, even when working in relatively narrow orebodies. The rising cost of extracting and treating the recovered ore and the lower prices available in the world markets has seen a growing trend to narrow mining methods.Traditionally narrow orebody mining has been carried out using hand held drilling methods and rail mounted boggers. Recent advances in mobile equipment now offers the operator of narrow method mines the opportunity to completely mechanise the mine from the drilling, through bogging to haulage, while maintaining minimal dilution in drive sizes to two metres wide or less.

Jan 1, 1993

Mount Isa mine is the largest underground mine in Australia and is located 2,000 kilometres north-west of Brisbane. This mine has been in continuous operation since 1931 and in 1986/87 the silver/lead/zinc stream achieved the peak annual mining rate of 4.7 million tonnes. At present about fifteen different steeply dipping stratiform orebodies are being mined to maintain an annual production rate of around 3.0 million tonnes. Out of these, only two orebodies (2 & 5) are amenable to sub level open stoping (SLOS) type bulk mining methods. This year only 150,000 tonnes are scheduled from pillars and remnant areas but in future, more sources will be required to meet the budget production targets.

Jan 1, 1990

By J C. de Vries

When times are tough in the mineral industry û as they have been for some time û typical responses by mining companies are to cut costs and/ or increase production. The latter is seen to spread fixed costs, thereby also reducing unit costs per tonne mined. However, most mineral deposits respond to increased production rates by lowering ore grades, so the reduction in cost per tonne of ore does not necessarily result in a reduced cost per unit of metal produced. The authorsÆ experience is that this process often leads to a mine plan that is a long way from optimal. Producing to the point where marginal cost equals marginal revenue may work well in a manufacturing operation, but it is not necessarily the best strategy for a mining company with a depleting resource. Variations in tonnage and grade with depth, ore reserve optimism and a variety of other factors conspire to produce variations in production rates and grade that often result in suboptimal outcomes and potential mine failure. Added to this is the focus of industry analysts and senior corporate management on such measures as unit costs and ounces in reserves. This is perceived to have the perverse effect of driving the share price down when strategies are adopted that actually improve the value of the mining operation, and vice versa! Many mine failures can be prevented by a close examination of the tonnage grade curve and an understanding of how margins, net cash flows and resulting business risk change with cut-off grades and rates of production. A few relatively simple analyses early in the evaluation of a project can demonstrate the tradeoffs between the main decision parameters, leading to right-sizing of the operation. Once major commitments to major capital items have been made, and reserves have been publicly reported, optimisation of the operation becomes much more difficult than if it had been done earlier. Such investigations can also identify the upside potential and downside risks associated with factors outside the companyÆs control. Many strategies that may enhance value in the good times significantly increase the downside risk in the bad times. What is often called risk analysis typically looks at superficial issues, and does not evaluate the major factors leading to the potential for financial disaster. This paper illustrates some of these major risks, and demonstrates how they may be fully evaluated so that corporate decision makers can make fully informed decisions that take account of the real risks.

Jan 1, 2003

MR. L. C. BALL, chief government geologist, Queensland, wrote: This paper is intended as a severely mechanical exposition of the means adopted to deal with tremendous inflows of water concurrently with development and exploitation; but incidentally it serves as a splendid exposition of close co-operation maintained between the geological and engineering branches of this large organization.I have been impressed by the completeness of the mine plans of 'Mount Isa Mines Ltd.; but only such a paper as this has brought fully to my understanding the difficulty and complexity of the solid geometry involved in the detection and plotting of the orebodies and their stratigraphic control, including faults and large-scale brecciations, and the managerial foresight that set going the initial investigations.The company's geological branch of course must be given full credit for the results attained, but it gives me pleasure that the Geological Survey of Queensland has been closely associated in much of the study.It is noted that complete drainage was affected, but it would be interesting to learn whether the brecciated zone will again become waterlogged and whether from above or from below, and whether there has been any change in the dissolved mineral content of the water as the work progressed.

Jan 1, 1939

By Muto S, Okada S

At Tamano Smelter, part of the furnace settler is electrically heated by electrodes placed internally. This practice provides good control of the settler conditions. The authors have been investigating improvements in furnace operations, especially to decrease the copper content in the slag discarded from the settler. The important operational points on the control of magnetite in liquid matte and slag are discussed on the basis of the thermodynamic calculation method developed by Prof. S. Goto. The behaviour of magnetite in the practical furnace has been studied by using a torsion magnetometer and a solid electrolyte oxygen-sensing cell.

Jan 1, 1980

The link between exploration success and new ideas from research and development (R&D), although often assumed, is rarely well explained or well illustrated. One issue is understanding the role of innovative ideas in the exploration process, and another is determining the relative contributing factors to an exploration success. A useful measure of gold exploration success over an extended time period and geographic area is discovery rate (θ): Discovery rate θ = gold discovered/exploration expenditure (usefully expressed as tonnes of gold per $1 million). The total gold discovered is strongly leveraged to discovery rate, as any increase in θ typically has a positive effect on exploration expenditure. Hence, improving the discovery rate is a key driver for a sustainable mineral industry, especially for gold. There are very few ways to influence θ beyond innovative R&D ideas and breakthroughs, and well-motivated and trained staff. The Australian gold industry has experienced exceptional exploration success with 9956 tonnes of gold discovered from 1979 to 2003, inclusive. This equates to: Discovery rate θ = 0.9 t/A$1 M Two-thirds of this gold has been found in the Yilgarn craton of Western Australia (6265 tonnes Au). Without this exploration success, there would have been no platform on which to build the current gold industry and to take advantage of elevated gold prices and advances in mining and processing. Several causes of the Western Australian gold success have been proposed, and more than one may be correct. Gold price, and mining and processing advances have all had influence; but exploration success and discovery of gold were essential to add to the miniscule resource base of 1979. A comparison of the exploration methods used to search for gold in the Yilgarn craton in 1979, and 1990, highlights a small number of breakthrough ideas introduced to the industry during the 1980s, and in most cases emanating directly from local R&D. By the 1990s, these ideas were being used in most gold exploration programs in the Yilgarn craton, and are still used today. These six breakthroughs are: epigenetic timing of gold deposit formation (ie after formation of rock sequence), chemical and mechanical role of host rocks, relevance of carbonate alteration haloes, gold dispersion in the regolith, optimal sampling media, and appreciation of landforms in exploration program design. Interestingly, gold exploration science in Western Australia entered the 1980s period without rigid paradigms in place regarding gold deposit formation; there was a balance between descriptive and genetic models, there was scope to research gold deposits from microscopic to global scales and there were highly effective industry research uptake processes in place: it is suggested here that these favourable conditions contributed to the exploration success and industry growth.

Jan 1, 2007

Projected cooling requirements for ERPM led to the first proposals for the large- scale use of ice for mine cooling in the early 1980's. Following successful research into ice conveying and ice melting a large ice plant was commissioned at Harmony in 1985 and a much larger 6000 ton per day plant is presently under construction at ERPM. A brief description of the mining project is given, followed by general descriptions of the surface ice plants and the ice conveying system, the systems for using the ice for mine cooling, and the control of the whole ice cooling System.

Jan 1, 1988

By H R. C Pratt, G W. Stevens

Hydrodynamic and mass transfer performance are presented for a 72.5 mm diameter pulsed disc and doughnut column of the type used by Western Mining Corporation, Olympic Dam Operation, for the extraction of uranium from sulphate media using Alamine 336 as extractant. For the present purpose, 4.0 g/L sulphuric acid was used as solute. The mass transfer data were interpreted in terms of the diffusion model, thus accounting for continuous phase axial dispersion. The results indicated that an efficiency corresponding to approximately one transfer unit over the 1.0 m height of the column was obtained. This efficiency is comparable to that observed by Gottliebsen (1997) for a pulsed perforated plate column using 173 gm/L sulphuric acid.

Jan 1, 2000

By J Szymanski, S Planeta

In pursuit of optimising the cemented rockfill system fragmentation of the aggregate, while travelling through the surface-to-underground aggregate transport raise, was investigated and a æfines estimationÆ equation was determined. When used with the rockfill strength estimation equation, the fines estimation equation enables an accurate estimation of the compressive strength to be derived theoretically. Optimum fill raise orientation was examined and recommendations are given depending on the varying stope dimensions. If the maximum dimension of the stope is less than 30.5 m (100 ft), a single, centrally located fill raise will suffice. However, as the stope dimensions increase, the number and orientation of the fill raises becomes more complicated and each stope must be examined on an individual basis.

Jan 1, 1998

Although most N.S.W. coal mines contain large amounts of combustible materials such as coal and timber, the introduction of mechanisation has extended the range of combustible materials now found underground. The role of combustible material in a fire is not clearly understood and as a result the assessment of these materials for flammability by small and large scale tests is doubtful. Extensive research has been carried out on the toxic and irritating gases evolved during the combustion of plastics. However, most autopsies report death due to carbon monoxide inhalation because the combined toxicity of smoke and fire gases is unknown.

Jan 1, 1981

By H S. Shin, H Jin, B H. Ryu, J Lee

Prospecting ice on the Moon necessitates drilling systems to obtain subsurface samples and measure the composition of ice deposits. Landers and rovers equipped with drilling equipment are essential for analysing ice and subsurface resources located at the Moon’s poles. These devices must be small, lightweight, low-power, highly efficient, and high-performance units to function properly in the extreme conditions of the lunar environment. Researchers have developed a prototype drilling apparatus capable of operating in atmospheric and cold environments. A newly developed drilling system in Korea, capable of performing not only sampling but also subsurface investigation, is introduced.

Sep 1, 2024

On account of the increased work required from the assay office, owing to the large additions which have been made to the smelting and superphosphate plants during the last few years, it was found necessary to build a more extensive and up-to-date assay office than the one that had been in use since the starting of the works some twenty years back.A site was chosen adjacent to the main office, so as to be free from smoke and dust.. The building is constructed of red brick, the over-all dimensions being 109 ft. x 37 ft. The roof is of fibrous-cement slates, 31 ft. high, with a two-to-one rise, and overlaps the walls to the extent of 4 ft. 6 in. on all sides.Special care was taken to give light to all working benches, fume cupboards, and balance rooms. The main chemical room occupies the entire western end of the building, and the fire room the entire eastem end. Between these two rooms are the superphosphate, refinery, and gold-parting rooms on one side of the central passage, and three balance rooms, general office, and cloak room on the other side. The height of the roof affords ample space above these central rooms for storage purposes, and also maintains a fairly even temperature. The ceiling of the main chemical and fire rooms is carried immediately under the slates, which gives a total height in the centre of about 25 ft.

Jan 1, 1918

By N Burgio

Block cave mines are often thought of as rock factories where high volumes of production are mined from a fixed area suggesting little requirement for geological input and control. Yet caving operations have peculiar and specific technical requirements from prefeasibility through to post-mining reconciliation. Whilst essential elements such as resource definition, geological interpretation and sampling strategies are common to all mining methods, planning for a block cave requires a different emphasis and philosophical approach in how we deal with these issues. We will examine why a geoscientist’s input is critical towards the successful planning, design and monitoring of a caving operation.

Aug 22, 2011