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By Kuipers A. J

Aberfoyle has been applying computer methods to mine geology in small to medium-sized underground mines since the early 1980's. Recently, the installation of DATAMINE software at the Hellyer Mine in Tasmania has allowed development of computerised applications which assist both mine geologists and mine planning engineers on a daily basis.Comprehensive data is entered into a database prior to survey coordinating to produce a processed database which can be accessed for construction of a variety of plots. The folded and faulted nature of the orebody contacts at Hellyer has necessitated the use of the structure contour method to provide a complete 3-D spatial interpretation. Computer-generated contact intersection points are hand-contoured before digitising and wireframing as a digital terrain model. This wireframe model can be sectioned in any plane for mine planning.

Jan 1, 1990

The use of rubber-tyred equipment in a decline mining system requires that roadways be kept free of running water. At Renison this is achieved by the use of stage pumping or gravitating to a major pump station and pumping from there directly to the surface. The frequent use of pick-up lines and pump boxes in the decline system provides a method of water control and reduces the amount of slimes in pump lines. The Bassett Fault structure, which lies on the hangingwall of the mine is the major source of ground water. This is encountered in diamond drill holes and exploration develop- ment. Dewatering of this structure is possible by controlling the flow from selected holes. Future pumping requirements may be predicted by analysing changes in the level of the water table and by calculating dewatering rates required to maintain ore reserves available for production.

Jan 1, 1977

Problems associated with gas management become more significant as exploitation of coal reserves in the Bowen Basin in Australia becomes deeper. At Oaky North mine, relocation of production from one area of the mine to another with a higher gas content required the use of pre-drainage, post drainage and inertisation techniques to enable production activities to continue largely uninterrupted. Innovative surface to inseam drilling techniques were developed for pre-drainage of reserves close to mine workings and have proven to be largely successful. The gas management techniques adopted and specific experience gained are discussed in this paper.

Jan 1, 2005

In a ætypicalÆ gold deposit each tonne of ore will contain tens of millions of very fine gold particles, whereas; at Bendigo the majority of gold in each tonne of ore is present in just five to 15 very coarse gold particles, a distribution more akin to diamond deposits. At Bendigo the minimum sample size required for good assay repeatability is estimated at 4.5 t for each assay. Drill core samples are several orders of magnitude too small to generate representative assays.The drilling data are characterised by a nugget effect approaching 90 per cent, a very skewed distribution and, on average, under-report in situ grade by 50 per cent to 75 per cent. Since 2002 Bendigo Mining NL has completed 47 000 m of diamond drilling, 1200 m of on reef development, collected and processed 100 bulk samples (150 t each), 800 mini bulk samples (50 kg each) and processed in excess of 25 000 t of ore through a pilot plant. The results of this work have provided the information required to develop and verify a robust grade estimation procedure. No standard geostatistical manipulation of the drilling assay data can generate an accurate grade estimate as the samples and associated assays are not representative of the ore being sampled. The recognition of this fact was critical as a radical transformation of the raw drill assay data was required to develop a workable methodology for grade estimation in such a high nugget environment. The aim of the transformation was to reduce the nugget effect and high variance and so approach a lognormal assay distribution. Ideally the average drill grade would approximate actual in situ grade and the assay distribution would reflect actual grade distribution within the reefs. Following the data transformation simple block modeling within the defined resources allows grade estimates to be made that can be used in the estimation of Indicated Resources and hence Probable Reserves. The grade estimates have been checked by extensive bulk sampling and processing of 25 000 t of ore (three per cent of total resource) through a pilot plant with planned full scale mining to provide the ultimate verification.

Jan 1, 2004

By E E. Hall, S, E D. Thimons, R J. Timko

The heart of mine ventilation science and technology is the protection of the life and health of the miner. Lung diseases that result from overexposure to various mine aerosols can largely be prevented by maintaining concentrations below prescribed limits. Maintaining safe aerosol concentrations depends, in part, on our ability to know what mine aerosol concentrations are in a timely and accurate way. The Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH) has been developing several new tools to help miners monitor respirable coal dust, silica and diesel particulate matter. This paper will discuss three main topics. First, the latest results of the person wearable dust monitor (PDM), developed by Rupprecht and Patashnick under CDC contract. The PDM was tested side-by-side with conventional samplers at a number of US coal mines and results indicated that the PDM was comparable to conventional samplers. Second, improvements to the dust dosimeter monitoring technique that includes a new pump with built-in pressure transducer and algorithm to convert differential pressure to dust concentration have shown good precision. Third, advances in the use of the detector tube technique to monitor tailpipe diesel emissions and ambient diesel particulate matter show that strong correlations exist between differential pressure measurement and elemental carbon in the samples.

Jan 1, 2005

By L Soebari, W Sunyoto

The Wabu Ridge Gold Skarn deposit is located at elevations of up to 3100 metres above sea level, in the Central Highlands of Irian Jaya, Indonesia, 35 km NNW of the Grasberg porphyry deposit. Wabu is a grass-roots discovery in an area with no previous gold mining history or record of gold mineralisation. A geological resource of 117.26 million tonnes at an average grade of 2.16 g/t Au (1.0 g/t Au cut-off) has been defined to-date. Mineralisation is hosted within a skarn occurring along the southern boundaries of the Late-Miocene age monzonite-diorite Pagane intrusive complex. The intrusive complex occurs in the footwall of a major EW structure, the Derewo fault, which displays sinistral strike-slip and reverse fault movement. The Derewo fault separates Derewo metamorphic units to the north from platform sediments of the Australian craton to the south. The skarn has a strike length of 6 km and is up to 1.5 km wide. It is developed within calcareous shelf sediments of the Tertiary New Guinea limestone group and is dominated by prograde garnet development. Gold mineralisation was deposited during retrograde alteration and is directly associated with arsenophyrite and bismuth minerals. Retrograde alteration is distinguished by a sequence of clinopyroxene , magnetite, epidote and hornblende, biotite and chlorite and lastly carbonate. Gold is associated with the biotite/ chlorite phase together with sulphides and precipitated as the result of fluid mixing. The Wabu Ridge Gold Skarn deposit was identified in April 1990 during a regional program of helicopter assisted stream sediment sampling of -80 mesh (180 microns) fraction and panned concentrate sampling. The initial discovery sample site was situated 15 km down stream from the deposit and returned 1.49 ppm Au for the stream sediment sample and 138 ppm Au for the panned concentrate sample. A regional airborne helicopter magnetics survey, conducted in early-1992, helped defined the main magnetite associated skarn zone and the extent of associated igneous rocks. Detailed follow-up commenced in May 1992 and consisted of detailed mapping, soil sampling and ground magnetics prior to drilling the first hole in October 1992. Drilling to-date has delineated a contained geologic resource of 8.1 million ounces of gold and potential exists for a larger resource.

Jan 1, 1999

The comminution process indicates that the most energy-efficient comminution system would be one where the particles leave the breakage field as soon as they reach product size. Contrary to the free falling gravitational (vertical) flow in crushers, the grinding millÆs energy efficiency essentially depends on ore characteristics and the discharge rate of broken particles, which in turn depends on how efficiently the discharge pump (grate and pulp lifters) operates. The essential function of a pulp lifter is to transport the broken material and slurry from the discharge grate out of the mill. Hence, the design optimisation of pulp lifters affects not only the energy efficiency and throughput of autogenous grinding/semi-autogenous (AG/SAG) grinding mills, but also contributes other process benefits such as improved wear life and operator-friendly steady and smooth mill operation. Following its introduction in 2006, OutotecÆs patented Turbo Pulp Lifter (TPLÖ) design has been retrofitted at existing sites and also installed in some new ones around the world. This paper will provide operational experience and data on how the TPLÖ design has allowed AG and SAG mills to operate efficiently.

Jan 1, 2009

The principles and practical applications of the Mogensen Sizer are examined, with particular reference to the experiences at Coal Cliff Mine, New South Wales. The Mogensen Sizer has proven to be a worthwhile alternative to conventional screening. It has the flexibility and capacity to offer a useful sizing tool, particularly in areas of confined space. It is simile in design and 1 in construction.

Jan 1, 1984

By Matsumura T, Takematsu T

The Brown Coal Liquefaction Process (BCL Process) has been developed by Nippon Brown Coal Liquefaction Co., Ltd. (NBCL), and a 50-ton-per -day Pilot Plant has been partially completed and put into operation by Brown Coal Liquefac- tion (Victoria) Pty., Ltd. (BCLV) at Morwell, Victoria, Australia. This Project has been sponsored by New Energy Development Organization (NEDO), an or- ganization associated with MITI, and has been promoted as a National Project with funding by the Japanese government. This project has also been conducted as a cooperative technology de- velopment project between the Japanese and Aus -tralian governments since 1980 and has been supported by the Victorian state government and

Jan 1, 1987

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

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 Onton W

During the latter part of 1936, conditions encountered in sinking the Main Ore shaft made it impractical and uneconomical to continue deepening it to serve haulage levels below the present No. 5 level. Plans were therefore made for an interior shaft, to serve new lower levels, that terminated above No. 5 level so that ore hoisted could be drawn off on this level and transported to the Main Ore shaft for final conveyance to the mill crude ore bin. The No. 2 interior ore shaft was only developed below No. 4 level and borehole ropeways with a winder located on the surface were installed in preference to an underground winder installation. No. 2 ore shaft with borehole ropeways commenced lead ore hoisting operations in September 1938. Apart from the copper ore hoisted in the war years of 1943-46, lead ore was hoisted to No. 5 level until September, 1951.

Jan 1, 1988

Gold mineralization like other low concentration high value commodities has gained the notoriety of being difficult to sample. This adversely affects the confidence that can be placed in resource estimates and ore reserves. As an example, it is not uncommon to find differences of the order of 30% between duplicates of a single sample sent to two different commercial laborartories. Two halves of drill core generally show marked differences in grade. Again differences of 50% are not uncommon in halved core. In the context of this type of "error" within the base data used for the resource estimate, many of the subtleties of computation methods and expert judgement of resource categories, are almost a case of shutting the gate after the horse has bolted. Managers, financiers and consultants must question the quality of the base data upon which resource estimates are made. They must insist that standard and duplicate samples are used to measure the accuracy and precision of commercial analytical laboratories, that sampling practices have been checked for possible bias and give tolerable repeatability. Further they must ensure there can be a realistic confidence in the estimates by correctly using these measures of data quality to quantify risk.

Jan 1, 1990

It is proposed to deal with those raw materials which are produced in South Australia to meet the needs of the country's steel industry. They are chiefly, iron ore, limestone and quartz.Iron ore and limestone are fed to the blast furnaces of Newcastle and Port Kembla together with coke to produce the hot metal charge for the open hearth steel furnaces.They are also qsed in the raw state in the steel furnaces to assist in the conversion of the hot metal to steel. The iron ore is quarried from' Iron Knob and shipped from Whyalla to Newcastle and Port Kembla, whilst the limestone is supplied from the deposits at Rapid Bay and shipped in the same manner.Quartz is used in the manufacture of ferro-silicon, an alloy which is added to the ladles of molten metal tapped from the open hearth furnace in the case of almost every grade of steel. It is obtained from a quarry situated between Iron Knob and Whyalla, and shipped to Newcastle.IRON OREWith the exception of several small quarries situated at Breadalbane, Cadia, Cowra, Crookwell, Michelago, Jerrawa and lerraama in New South Wales, the iron ore requirements of Australia's steel industry to date have been met from Iron Knob and the Middleback Range in South Australia.Several of the small deposits in New South Wales were worked during the war years of 1941-44 during the shipping emergency and produced 1,355,417 tons, compared with an output of approximately 43,000,000 tons from Iron Knob between 1901 and 1949.

Jan 1, 1951

The necessity for good management and economic working in our mines and ore-dressing sheds is impressed upon us by the present low prices of all our metals. Silver, lead, copper, and tin have all suffered a heavy decline during the last six or twelve months, and many mines have been shut down simply on account of the low market value of the ore produced. After fully considering the position of the mining industry. I am convinced that considerable improvements will have to be made to make it as prosperous as it ought to be. The most obvious of these improvements are good management, good machinery, and as little interference by directors as possible. If these conditions are insisted upon and carried out efficielltly a poor mine may have a chance to weather the storm.There is no doubt that the present depression is the refilult of over-speculation and general loss of confidence by which the whole commercial system has been affected, and every branch has suffered more or less, mining not excepted. It has suffered heavy losses in the past, and the future is not over bright we are, therefore, compelled to be careful in everything by which mining is affected and savings can be secured.

By L C. Thompson

Biomineralisation is the process by which microorganisms mediate and catalyse inorganic reactions so as to form new mineral assemblages. The goal of biomineralisation as a remediation tool is to control microbial processes and their environment so as to sequester and immobilise specific toxic metals within exceptionally strong bonds of neo-formed mineral assemblages. In this way, the bound metals are no longer mobile within a geological time-scale. Applied biomineralisation uses microorganisms, which are isolated from a metal waste environment and are selected for their ability to rapidly catalyse neo-mineral development from dissolved or leachable metals. A typical waste environment will contain microbes that contribute to the mobilisation of metal contaminants as well as microbes that possess the potential for remineralising available metals. Selection and augmenting the correct combination of bacteria and eliminating the competing mineral degrading reactions are the key to applying biomineralisation as an in situ remediation process. Applied biomineralisation harnesses the microbesÆ ability to stabilise toxic soluble metals into non-mobile mineralassemblages. This paper will discuss and demonstrate the biomineralisation process through several case studies including the Summitville mine site in Colorado, the McCoy-Cove mine in Nevada, the Argonaut mine in California, and an historic lead site in Crooksville, Ohio.

Jan 1, 2004

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009

By Jefferson CW

Middle-to-Late Proterozoic stratigraphy and metallogeny in the eastern part of the Canadian Cordillera and in South Australia are strikingly similar. In both areas, thick, predominantly shallow-water strata and their contained mineral deposits can be divided into three sequences (A, B, C) that record episodic and prolonged continental rifting. It is proposed that Adelaidean strata of Australia were deposited adjacent to Belt-Purcell, Mackenzie Mountains and Windermere strata of the Canadian Cordillera within an epicontinental trough of a "Hudsonia" regacontinent. With the final rifting of this trough, the paleo-Pacific ocean was born. By Early Cambrian time, Australia- Antarctica was on the trailing "east" side of the nascent megacontinent, Gondwana, and was being modified on the "west" by accretion in the Pan-African event. North America, more or less surrounded by trailing edges at this time, was analogous to the Cenozoic African plate. This hypothesis accommodates the available paleomagnetic and radiometric data. It has implications for pre-Pangean plate tectonics, paleogeography, and the predictive metallogeny of both areas.

Jan 1, 1987

By Hanna P

Coal geologists are under pressure to minimise exploration expenditure, maximise interpretation confidence and produce the results often too soon. This pressure continues to increase as companies are forced to evaluate borderline economic deposits which are usually deeper and more hazardous, such as the Togara North and Togara South projects in Central Queensland.

Jan 1, 1998

Projections of metal requirements for Japan and the United States indicate growing competit- ion for Australia's mineral output and a critical need for continuing discovery of new reserves. These projections may be modified by economic, social and political controls - the most import- ant factor probably being a shortage and the high cost of risk and development capital. Changing ownership patterns toward joint ventures and increased state participation are anticipated. New developments in global tectonics and metallogeny delineate favourable zones for ex- ploration and permit establishment of priority search areas even in regions of poorly known geology. Declining ore grades and special character- istics to meet technological requirements may modify identification and evaluation criteria. A broad approach considering all environments of concentration within the geochemical cycle is re- quired within any metallogenic province. The exploration geologist must be able to integrate geological theory, mining technology and financial analysis to establish well defined exploration objectives, in terms of economic and geologic models, in concept-oriented programmes.

Jan 1, 1973