Search Documents

The C.S.A. copper lead zinc mine, located seven miles north of Cobar in Central Western New South Wales, is the largest known mineral occurrence in the Cobar Mining Field. Hosted by the steeply west dipping, west facing sediments of the Cobar Group, the generally discordant orebodies occur within a strike width of 600 ft and an overall strike length of 1200 ft. They comprise lenticular steeply north pitching and east dipping zones of sulphide mineralisation which range in composition from massive pyrite-sphalerite-pyrrhotite--galena to less massive pyrite- pyrrhotite-chalcopyrite varieties. The thinly bedded siltstones, shales and graywackes hosting the mineralisation appear to have derived many of their constituents from volcanic sourcesä They have been metamorphosed to the greenschist facies of regional metamorphism. At least two stages of deformation and folding have occurred. The first stage folded the rocks on a south pitching fold axis into their present configuration, and super- imposed a strong axial plane cleavage which subsequently guided the emplacement of the mineralisation. The second stage of deformation is considered to have controlled the zonal distrib- ution of the orebodies and the appropriate fold axis appears to coincide with the long axis of the orebodies.

Jan 1, 1969

By Hatherly P, Holt GE, McNally G

The current methodology for delineating and subsequently evaluating coal reserves is based on the use of vertical drill holes and surface based geophysics/geology. These techniques have three major problems, these being respectively:-a) Vertical drill holes can only provide a small sample of the coal seam and stratigraphy. Therefore the planar variation in coal reserve and environment parameters can only be approximated.b) Although surface based geophysics has had its fair share of success in recent years, there are still environments which have masked the finding of major structures.c) Access to drill sites is difficult at some locations due to mountaineous terrain, standing water and environmental impact.

Jan 1, 1985

By Lee RJ

A significant basemetal province is recognised in the southern part of the Bonaparte Basin, Western Australia. Epigenetic stratabound carbonate hosted Pb-Ag-Zn mineral- isation occurs in dolomites of Tournasian age within a marginal marine transgressive carbonate and fine grained clastic sequence, spatially overlying the lagoonal facies of a Late Devonian reef complex. The deposits comprise coarse grained sulphide mineralisation characterised by high Pb:Zn ratios (10:1) and high silver (50 g/t) content. They occur at shallow depth, are flat to moderately dipping, and form a discontinuous mineralised trend at the margin of the Sorby Platform, which flanks a Precambrian basement high. Host rocks are predominantly sedimentary breccias and dolomitised footwall carbonates associated with a significant local unconformity transgressed by a siltstone cap rock sequence. The deposits are structurally related to synsedimentary growth faults, local basement highs and tensional en-echelon breccia systems. Fluid inclusion studies have concluded that mineralisation was deposited from a low temperature (85¦C-115¦C) saline ore forming solution. Lead isotope work reveals a Precambrian genetic source of the lead. Locally remnant textures after sulphates are recognised within the host sequence together with common bitumen and oil shows. Reduction of sulphate to H2S was possibly facilitated by either bacteria. activity, or by residual hydrocarbons which acted as a reducing agent. An alternative source of H2S may have been afforded by the thermal degradation of hydrocarbons. A 'mixing' genetic model is proposed for the mineralisation, which conceives the expulsion of metal enriched basinal brines followed by their precipitation as sulphides after mixing with locally derived reduced sulphur solutions at relatively shallow depths in their structural/stratigraphic sites of ore deposition.

Jan 1, 1986

By Sakurai F

Akita Zinc Refinery of Mitsubishi Metal Corporation (MMC) started operation in 1953 with a capacity of 560 tons of electrolytic zinc per month. Its capacity has been expanded gradually and reached 8,100 tons per month in 1973. However, present production level is about 6,500 tons per month due to the depressed zinc market. In 1963, newly developed sulphate roasting was incorporated for residue treatment. Since 1973, electric power from Ohnuma geothermal power station of MMC has been supplied in addition to hydroelectric power from Komata power station of MMC. At present, about 40% of power is supplied from our company's power station and the rest is from the power company. Recent customers' demands for zinc prod- ucts include various kinds of shape, weight and chemical composition of galvanizing zinc alloy. It is necessary for zinc producer not only to meet the requirements of customers but also to enhance the value of zinc product in order to expand the market of zinc.

Jan 1, 1987

By Grant J

In surface mining, significant improvements in efficiency can be obtained through greater control over the formation of the muckpile. By tailoring the muckpile shape and its looseness to the requirements of the excavating equipment savings can be rea- lised through increased production, machine life and reduced maintenance. For instance, one open cut coal mine has recently estimated that a 2001o improvement in its front row throw would realise $320,000/year savings in rehandle costs alone. Previously greater throw has been achieved by increasing the powder factor through increased quantity of explosive or by drill- ing a larger number of holes-both at a significant cost penalty. However a recent series of experimental blasts demonstrated that it was possible to achieve a twofold increase in the distance of throw of a single row blast by simply changing delay timing alone. The Nobel Electronic Delay Detonator was used to provide the timing flexibility and control required for a thorough study of the effect of blast timing on heave. Whilst it is well accepted that the front row of a blast dominates the extent of throw, it was also found that the profile of the blast could be significantly altered. To date, the general consensus has been that the muckpile for- mation from a blast is a function of the blast geometry, the rock type, the explosive and the initiation sequence. Typically the geometry, rock type and initiation system have a far greater impact than the explosive type. This has been demonstrated by many high speed film studies. However the extent of influence via initiation has rarely been fully evaluated, owing largely to the limited control offered by conventional detonators.

Jan 1, 1988

The Lower Proterozoic metasediments of the Pine Creek Geosyncline form a chrono- stratigraphic sequence of mainly greenschist- and amphibolite-grade shallow-marine to supratidal pelites, psammites, carbonate rocks, and volcaniclastics which in places rests unconformably on Archaean basement. Granite and later dolerite intrude the sequence, and are associated with the major orogenic 1800-m.y. event which regionally metamorphosed the sediments. Most mineralisation is stratabound, and can be related at least partly to volcanic activity. Uranium mineralisation is mainly confined to particular carbonate-rich horizons near basement. Other metals are mainly in small hydrothermal deposits near intrusive granite. Specialist studies indicate that uranium was leached from its source rock, and probably carried as carbonate complexes in highly saline fluids at between 100 and 3500 C. Precipitation took place by redox reactions in breccia zones in carbonate rocks; these zones were formed by carbonate solution or diapiric movement of evaporites which preceded the carbonate. Extensive chloritisation in the ore zones suggests metasomatism by Fe- and Mg-rich fluids which may have evolved during dewatering of the evaporites. The main mineralising event took place after the 1800 m.y. metamorphism, and was probably

Jan 1, 1979

By Mroczek C. R, Evans D. A

Renison is a world-class ore deposit that has been mined for over 100 years. It currently has reserves of 5.06 Mt @ 1.88 per cent Sn and a projected mine life of 8.5 years. Recent advances in the geological understanding of the deposit have been associated with detailed structural and geophysical investigations accompanied with the discovery and exploitation of the Rendeep orebodies. Mineralisation is linked to the forceful emplacement of the Devonian Pine Hill Granite that resulted in a complex brittle (-ductile) deformation of the Eo-Cambrian host stratigraphy. Dilation jog development on the Federal-Bassett Fault in the Federal and Rendeep areas provided access for cassiterite-rich magmatic hydrothermal fluids responsible for carbonate replacement Mineralisation.

Jan 1, 1997

By Yagi Y

The double track railway tunnel, called the Second Shirasaka Tunnel is being constructed under the supervision of Japanese PTational Rail- ways (JNR) in the tertiary soft rock strata in order to speed up the railway transportation. This tunnel (L=1765m), located in a central part of Japan, is excavated by the machine (roadheader), while the adjoining First Shirasaka Tunnel (L=1296m), completed five years ago, was driven by the blasting, and NATM is adopted in both tunnels. The geological features in this region are Neogene Tertiary of Miocene sediments consisted of mudstone, the sandy mudstone and the alter- ation of these rocks, having a squeezing be- haviour. And the geological structure is as complicated as some anticline and syncline structures, large or small scale exist, and as a lot of faults are found. The machine excavation manner using road- header is adopted in this tunnel to minimize the effect of excavation because there is a possibility of the occurrence of landslide due to the tunnel excavation, and also because local inhabitants reside on the ground surface.

Jan 1, 1987

Blasting, particularly bench blasting, uses finite length cylinders of explosive close to two free faces. The rock to be blasted is usually intersected by a complex 3-D system of joints. To fully simulate a blast, a 3-D dynamic model is required. It is shown that the static stress distribution around a long cylinder can be reproduced by superposing the static stress distribution of a suitable chain of spheres. Thus, the dynamic results for individual spheres given by Favreau (1969) can now be substituted for the static results to give a dynamic model of the stress distribution around a long cylinder. Comparison of measured and computed waveforms show that the measured waveforms are much more attenuated and dispersed than expected. The consequences for explosive evaluation and design are Discussed.

Jan 1, 1990

By Dennis B

The Hilton Mine, 20 km north of Mount Isa was discovered in 1947. The underground mine has been a significant producer from 1989. The long development history is the result of complex orebody geometry, difficult metallurgy, dewatering problems and competition for development funds from the then expanding Isa Mine at Mount Isa. At present it produces 1.4 million tonnes annually. Its 21 million tonnes of reserves are necessary to supplement Isa Mine production.Hilton Mine is located in the Urquhart Shale formation of the Mount Isa Group, within the Mid Proterozoic Mount Isa Inlier. The seven developed orebodies have suffered strong structural deformation. Each orebody has a unique mixture of mineralogy and texture which effects ore value and metallurgical performance. These characteristics have proven useful for correlation purposes.The faulting and folding have caused difficulties with orebody interpretation, geomechanical complexities and has influenced the choice of mining methods: Initial cut and fill and open scope designs have given way to bench mining methods in response to better understanding of the eedloav and economic constraints.

Jan 1, 1993

By Stanley I. M, Brett D, Dickson R

The Mt Lyell Mine, situated in Queenstown on the west coast of Tasmania, has a production history of more than 100 years. Previous mining activities have resulted in substantial modifications to environmental conditions at Mt Lyell and disposal of sulphidic waste rock across the lease has left a legacy of on-going environmental impacts including acid drainage (AD). In 1995 Copper Mines of Tasmania (CMT) was granted a mining lease Irons the Tasmanian State Government for redevelopment of Mt Lyell and indemnity from actions concerning pollution from previous occupation and use of leased land. The Environmental Management Plan (EMP) for the Mt Lyell redevelopment committed CMT to be responsible for waste rock dumps generated from their activities and to ensure that management is in-line with best practice environmental management principles. CMT commenced commercial production in December 1995 with sulphidic material from development of the underground Prince Lyell mine reporting to a single waste rock dump constructed according to a management plan developed in July 1995 and superseded by a management plan for extension in May 1997. The CMT waste rock dump currently has a total capacity of 220 000 m- and approximately 120 000 m3 of rock have been placed to-date. Material reporting to the dump is placed in a densely compacted state to a controlled surface profile. The dump is clay capped and a final revegetated soil layer placed on top. A rock pitched drain extends down to a wetland area in order to remove stormwater and minimise possible soil erosion on the revegetated sections. An integral part of the management plan for the waste rock dump involves characterisation of waste rock to identify geochemical rock types according to acid forming potential with provision for selective placement within the dump. High-risk materials are selectively placed and covered within the core of the waste rock dump, where possible, to control sulphide oxidation. Monitoring equipment has been installed in the waste rock dump by the Australian Nuclear Science and Technology Organisation (ANSTO) and an on-going monitoring program has been established to demonstrate the integrity of the dump cover as a barrier to the influx of atmospheric oxygen into the dump. The overall objectives of this program of work are to control the oxidation of sulphidic waste rock in the waste rock dump, minimise the risk of AD, prevent pollution of the aquatic environment and thereby demonstrate the integrity of the CMT waste rock dump management Strategy.

Jan 1, 1997

Welcome to Mount Isa- my home city and without doubtthe base for what promises to be the most exciting mineral development yet seen in Australia.Mr. Chairman, it also gives me great pride to representthis area in the Queensland State Parliament as well as being the Minister for Minerals and Energy in the Queensland Government.Mount Isa is now part of the Australian mining industry folklore.It is all what a good mine is all about. It is. all what a good community is all about.

Jan 1, 1993

The microstructures exhibited by ilmenite in its association with other oxide minerals have been the subject of a number of papers, the most comprehensive of which is that by Ramdohr. The following observations in some degree extend his conclusions. They are based upon a study of about sixty specimens of "massive" ilmenite and titaniferous ores from a number of wIdely 'scattered Australian localities. Specimens of this character proved much rarer than was expected. The collection was gathered together through the generous aid of the University Geological Departments, Geological Surveys, and Natural History Museums of the several States of the Commonwealth, all of which contributed such specimens of local origin, as they possessed. Special thanks are due to Dr. E. S. Simpson, of Western Australia, who made available several highly interesting specimens, together with his...

Jan 1, 1938

Alluvial gold exploration is aimed at recognizing areas of anomalous gold content as evidenced by the nature of the drainage system, its age, geomorphic history and other features of the geological environment including the provenances. Subsequent studies to quantify the findings are governed by the need for accurate data based upon precise measurements. Computerization allows the use of more complicated mathematical procedures than are feasible manually, thus promoting the development of more advanced technological aids. Data banks provide the means of storing vast quantities of information for instant recall.Sample representivity is a major problem and a clear understanding of both sampling and analytical requirements is essential for dealing with problems arising from variations in sample size and particle size distribution. Field samples must always be large enough to ensure adequate representivity or the sampling has failed in its purpose.

Jan 1, 1984

In the hard rocks of the Nordic countries of Norway, Sweden and Finland underground works have a long tradition. Today the subsurface has been taken into use for a wide variety of purposes. In this paper only the more uncon- ventional examples are described such as caverns for drinking water, sand bunkers, molasses silos, wine and liquor stores, cold stores, heat storage, waste disposal and state archives. The particular use of unlined high pressure tunnels and socalled air-cushions for hydropower schemes is discussed. The dual use of subsurface air-raid shelters for sports activities seems to be a special Nordic tradition. Some cost figures are given and the advantages of using the underground is Discussed.

Jan 1, 1987

The Iron Prince orebody occurs within the Lower Middleback Jaspilite Horizon of the Middleback Group and consists of hematite within host rocks of jaspilites and schists. The ore was probably the product of leaching of silica from jaspilites and replacement by iron, concentrations occurring in suitable structural traps. The narrowness and the presence of extensive dolerite amphibolite dykes within the orebody make it essential to operate a grade control programme in advance of the faces. Information from drilling is drawn up on bench plans, step plans and impurity overlays, and these serve both in day to day production planning and in long term planning. Mining is done selectively by open-pit methods and blending conducted by keeping at least three faces of different grades of ore open at any one time. No stock piles of ore are kept for blending, but contact ore, contaminated ore and enriched material are dumped for later beneficiation.

Jan 1, 1971

The construction of mine headframes of reinforced concrete is not a new departure as many structures have been built of this, material particularly in Canada and South Africa. This type of construction has been satisfactorily tested in service and is now accepted by the mining fraternity.The two headframes at New Broken Hill Consolidated Limited are the first structures of this type to be built in Australia, and provide an interesting application of reinforced concrete design and construction.Reasons for Adoption of ConcreteDuring 1947 the writer visited D.S.A. and Canada and inspected three headframes, of reinforced concrete construction.Leading details are as follows:(i) Hollinger Gold Mines. (Timmins, Ontario) : Height of sheaves 110 ft. Shaft has provision for 4 skips each of 12,000 lb. capacity. Structure incorporates surface crushing plant.(ii) International Nickel Corporation-Murray Shaft (Sudbury): Height to sheaves 153 ft. 6 in. Shaft provides for 2-12 ton skips and 2 cages. Surface crushing plant built integrally with frame.(iii) Asbestos-Johns Manviae (Quebec): Height of sheaves 116 ft. Shaft provides for 2 skips 200 cu. ft.

Jan 1, 1956

Introduction.History of Stope Filling at Mount Isa.The Need for a Systematic Fill Programme.Reasons for Filling.Fill Materials and Tonnages.Rough Mullock Fill.Quantities Readily Available.Fill Pass Development.Stope Preparation.Drainage.Hydraulic Sand Fill.Initial Experiments with Mill Tailings.Surface Layout.Operation Procedure.Underground Pipe Lines.Life of Sand Pipes and Cones.Drainage.Old Tailings Dam Sands.Quantity of Fill Placed.Pillar Tonnages.Conclusion and Acknowledgment.INTRODUCTIONFilling practice outlined in this paper refers exclusively to the Black Star section of the mine. The stope filling necessary early in the life of the Black Rock and portions of the Rio Grande sections is not to be confused with the current filling programme.

Jan 1, 1953

By Stewart WJ

Australia's first offshsore well was spudded in on 27th December 1964 and resulted in the discovery of the Barracouta gas field. Further exploratory drilling led to the discovery of the Marlin gas field in December 1965, the Kingfish oil field in April 1967 and the Hblibut oil field in June. 1967. In September 1968, a small oil reservoir was found in a sand below the main Barracouta'gas reservoir. The Snapper gas field was discovered in May, 1968 Information on exploration activities associated with the discovery of oil and gas in the Bass Strait area may be found in the paper, "Exploration in the Gippsland, Bass and Otway Basins, Australia" by B. M. Hopkins. _ Development of the commercial fields is being undertaken on an equal participation basis by Hematite Petroleum Pty. Ltd. and Esso Exploration and Production Australia Inc. Esso Standard Oil (Australia) Ltd. is responsible for the design, construction and operation of the production facilities.

Jan 1, 1970

The Teutonic Bore deposit lies in a major greenstone belt within the Archaean Yilgarn craton of Western Australia. It occurs towards the base of a suite of tholeiitic basalts, some 100 m above a felsic volcanic pile of rhyolitic composition. Sediments comprise a minor, albeit important, percentage of the mine stratigraphy.The deposit consists of a single, steeply dipping lens of massive sulphides totalling 1.4 million tonnes grading 4.16 per cent Cu, 16.4 per cent Zn, 1.22 per cent Pb and 203 g/t Ag. In addition, cross cutting "stringer" mineralisation in the footwall contributes a further 0.75 million tonnes at 2.38 per cent Cu, 1.92 per cent Zn and 52 g/t Ag to the mining reserves. Principal primary sulphides in massive and disseminated mineralisation are sphalerite, pyrite, chalcopyrite and galena, while minor amounts of arsenopyrite and argentiferous tetrahedrite are also present. Weathering has affected the primary mineralogy down to at least 90 m, resulting in a strongly leached oxide profile to about 85 m, overlying a thin, erratic zone of chalcocite supergene enrichment.Lateral metal zoning is marked both in massive sulphide and stringer mineralisation, with Cu/Zn ratios decreasing away from the centre of the orebody. Alteration is well developed in association with footwall stringer mineralisation, changing from a central Fe-Mg carbonate, chlorite and silica alteration zone below the massive sulphides to an outer halo of sericitisation. The spatial distribution of these minerals is patchy. Geochemically, the footwall alteration zone is characterised by central Cao, Na20 and Sr depletion (with less regular enrichment of SiO2 , Fe and MgO), surrounded by a peripheral zone of K20 enrichment.Evidence supports a classic volcanic-exhalative origin, involving submarine discharge on the flanks of a rhyolitic dome and accumulation of the massive sulphides in a local palaeotopographic depression. The sulphides overlie their feeder zone as shown by alteration and stringer mineralisation. Tholeiitic wallrocks are thought to be genetically unrelated to the mineralising solutions, although their presence as a cap over the felsic volcanics may have permitted the build up of a circulating metalliferous brine system prior to sulphide deposition.

Jan 1, 1984