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By Yambu J, Titus K

Geotechnical investictations and monitoring have been integral to development of the Porgera Gold Mine. The steep, unstable terrain has required a program for monitoring of slopes and foundations which includes survey stations, borehole inclinometers and piezometers. Case studies of the Maip Pass landslide, Yakatabari land-slide, Anawe Plant Site CIP pond excavation and batter, and a load test study for mine waste dumps are presented.Monitoring is needed to ensure that geotechnical risk is kept to a minimum. A vigilant program will be required for the life of the mine.

Jan 1, 1994

Shear strength testing of rock discontinuity surfaces has been undertaken at a considerable number of open pit gold mining operations in Western Australia, as part of geotechnical studies of pit wall stability. These mining operations are located in geological settings that are typified by highly weathered and/or chemically altered rocks that contain significant structural fabric in which accurate and representative measurement of shear strength is essential.Little of the published rock discontinuity shear test work and back-analysis of failures has been conducted on weathered discontinuity surfaces, at low normal stress levels which are comparable to Western Australian conditions. Available shear strength data are reviewed and the following aspects of shear strength testing are considered:ò the need for shear strength test work and the amount of testing required;ò review of laboratory testing methods and the quality of the results; ò presentation of the test results;ò discussion of the shear strength failure criteria; ò interpretation of the test results;ò summary of test results for a variety of rock types, degree of weathering and discontinuity surface conditions;ò a review of laboratory and field shear strength data to illustrate the amount of variability that can occur; andò a monitoring strategy is proposed to manage the uncertainty associated with discontinuity shear strength.

Jan 1, 1992

By Stone I

Tahmoor Mine is located in the southern Sydney Basin 80km south-west of Sydney and produces 1.2 MT of Bulli Coal annually. Bord and pillar methods used to date will be supplemented by a longwall system. Difficult roof conditions have been experienced since mining began in 1979. A dominantly horizontal stressfield promotes shear failure in the thinly interbedded roof sequence of shales, laminites, siltstones and fine sandstones. General roof conditions and failure characteristics are related to the angle between the roadway direction and the principal horizontal stress direction. The apparent stressfield changes direction, magnitude and the ratio of principal horizontal components across the mine workings in response to both in situ and mining induced causes. Initial roof support of 5 x 2.1 m bolts per W-strap at in intervals, with mesh, was upgraded to include RSJ's in order to support areas of failed roof. This support system was inefficient and costly. A third system of support emphasizes roof reinforcement with full resin encapsulation of 2.1 m bolts in W-straps. The number of bolts per strap (6-8), extra butterfly straps and bolts, and W-strap spacing is determined for each area by expected roof and stress conditions. Intersections are pre-bolted and ribs are supported in some areas. Pillar dimensions, order of drivage and roadway width have each been altered to improve roof control. The intensity of roof deformation at the face varies from panel to panel and causes development rates to decrease to 30% of the maximum. 1. Manager, Tahmoor Mine, Tahmoor, N.S.W. 2. Senior Geologist, BP Coal, Picton, N.S.W. Roof conditions in each area of the mine are characterised and then projected to future development areas based on the relationship between stressfield orientation, relative roadway direction and face conditions. Planning information available includes expected development rates, roof support requirements and areas of changing conditions. Future improvements of strata control involve defining support design parameters for the range of mine conditions already seen at Tahmoor.

Jan 1, 1986

In recent years, the. art of electric steelmaking has received a great deal of attention, and naturally, much controversy has existed from time to time regarding the relative merits of different practices and tywes of furnaces. Nevertheless, at the present time, the basic principles of the process are reasonably well established, and by far the greatest percentage of electric steel is a product of the basic lined, direct arc type furnace. Ferro alloy manufacture has demanded the development of furnaces having very different characteristics to those used for steel. Some special alloys, however, require conditions of manufacture which are more closely approached in the steel type furnace, and thus the latter has been adapted where necessary for the production of these alloys.One such alloy, low carbon ferro-manganese, is manufactured at Whyalla, South Australia, in a basic-lined, direct arc furnace, which is used alternatively for the production of alloy steels.BRIEF HISTORY OF THE ELECTRIC FURNACEThe principle of melting by electricity was first applied to the melting of iron in 1879 by William von Siemens, whose equipment consisted of a small crucible into which were introduced two carbon electrodes. Very little practical development took place in the next 20 years, although in 1890 a Frenchman named Heroult designed a direct arc furnace for the production of ferro alloys. At the beginning of the 20th century, several types of furnaces were patented for steel melting, the most important of these being the Heroult, using a direct arc, the...

Jan 1, 1951

Myuna Colliery long term ventilation requirements were included as part of the overall planning of colliery construction and underground development. Ventilation, during the simultaneous sinking of two drifts and the downcast shaft, was accomplished by established methods of ducted exhaust and blower fans. Drivages for the 3 seam interconnections of shaft and drifts were ventilated by extension and duplication of the exhaust systems. Ventilation, for the below seam extension of the belt drift, construction of between seam and below seam bins, and the completion of a circular between seam drift, required a step by step changeover to a temporary main ventilation exhaust fan mounted adjacent to the top of the completed downcast shaft. The second, permanent upcast, shaft was commenced and colliery production started one seam at a time, using the transport drift, while the underground bins, belt and between seam drifts were completed. The uocast shaft was completed and a connection made in the upper seam, completing all contract mining and allowing the main fan to be erected. The permenent twin centrifugal fan system was installed, commissioned and test run to

Jan 1, 1983

By Greaves J. N

The U.S. Department of Interior, Bureau of Mines, is investigating the treatment of refractory gold ores. Chlorination in the treatment of refractory gold ores is applicable in many low-grade gold operations. When usable, this treatment provides an economic means of consuming sulfides and deactivating disseminated organic carbon. Chlorination, however, is a pretreatment technique that requires the neutralization of the chlorine prior to leaching the ore with cyanide. Research by the Bureau has extended the present chlorination technology to allow for the recovery of gold without the use of cyanide and allow treatment of some ores presently deemed untreatable by gold operators using cyanidation or chlorination/cyanidation techniques. Chlorination without carbon of two carbonaceous ores extracted between 1 and 20 pct of the gold; however, carbon-in-chlorine (CICL) treatments resulted in about 90-pct recovery with a reduction in carbon loading. A statistical design campaign for stripping metallic gold from the carbon loaded in a chlorine environment demonstrated elutions exceeding 90 pct.

Jan 1, 1991

By K Nilsson, G Cheong

Troy Resources NL acquired a 70 per cent interest in the Mina Sertpo gold project in Goißs State, Brazil, in 2001 following a successful bid for the highly competitive international tender of a tenement package put out by Western Mining Corporation (WMC). The Sertpo deposit is located on cleared grazing land 380 km west of Brasilia and is 30 per cent owned by Amazonia Mineracao Ltda, a private Brazilian company. It is a small high grade open-pittable orebody with a measured and indicated resource of 108 000 tonnes at a grade of 49.7 g/t for 172 500 ounces using a 2.0 g/t cut-off. Troy undertook the project management and development of the project while Amazonia managed the exploration activities and provided other services as required. The project development involved drilling metallurgical test holes, scouring the world to locate an available and suitable second-hand plant, and arranging shipping to andreconstruction in Brazil.

Jan 1, 2004

By Yinxiang W, Chunlai Y

In older to improve efficiency of surface pre--grouting in sealing off water in heavily water-bearing strata, such as sandstone,siltstone and limestone, several methods have been used in China, they are ; intermittent pre-grouting, adjusting pre-grouting parameters and stepwise repeated pre-grouting methods. The paper describes effect of deviation on water sealing in pre-grouting. Deviation correction measures, like mechanical, technological and changing hole position methods have been introduced with satisfactory results in practical engineering projects without increasing the volume of engineering project and without causing delay.

Jan 1, 1988

By I M. Platten, S C. Dominy

The evaluation of historical goldfields is currently topical, reflecting a high gold price, improvements in knowledge and technology. and lack of greenfield sites. Many goldfields comprise narrow gold-quartz veins which are structurally complex with an irregular distribution of gold; variable geometry and architecture; and display late deformational effects. The study of historical mine records can be an important tool during early and advanced project evaluation since it contributes to understanding the orebody, exploration target size and setting expectations. The historic Engineer Mine property is located 32 km west of Atlin, British Columbia on the east side of Tagish Lake. The economically important Engineer and Double Decker veins belong to a NNE-SSW vein set. These are narrow, commonly <2 m dilational veins with a minor sinistral strike component and of an epithermal type. Documented ore production between 1910 - 1952 is recorded as approximately 14 263 t at 39.4 g/t Au and 19.5 g/t Ag (for 18 000 oz Au and 8950 oz Ag). The underground workings consist of about 5500 m of tunnels, shafts, raises and stopes over eight levels. The mine is currently being re-evaluated. In 2011, an Inferred Mineral Resource of 41 000 t at 19 g/t Au for 25 000 oz Au (at a 5 g/t Au cut-off) was defined from historical data supported by modern drilling into the Engineer and Double Decker veins. A surface and underground bulk sampling and milling program was undertaken in 2011.CITATION:Dominy, S C and Platten, I M, 2012. Application of historical data to estimate a mineral resource at the Engineer gold mine, British Columbia, Canada, in Proceedings Narrow Vein Mining 2012 , pp 81-100 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

Reduction of Iron Content from Silica by Gravitational Processes In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample which was provided from Shenin silica mine using gravitational processes including jig machine, multi gravity separator (MGS), shaking table and spiral. The silica sample contains 93.75 per cent SiO2, 0.44 per cent Fe2O3, 2.78 per cent Al2O3, and 0.08 per cent TiO2 and the Fe2O3 has to be reduced to about 0.1 per cent or less than 0.02 per cent. Mineralogical studies and XRD analysis indicated the presence of haematite, pyrite and goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections yielded that the degree of freedom of silica is more than 80 per cent in the range of -300 +212 mm. After elimination of fine particles, at first nine tests were carried out on crusher product (in two size fractions), wet rod mil product and scrubber product by means of Jig Machine. The best results were obtained with about 0.15 per cent Fe2O3 on rod mill and scrubber product which was not desirable. Thereafter 7 tests were carried out using shaking table; the best results were obtained with about 0.14 per cent Fe2O3 on rod mill and scrubber product which was not desirable. MGS showed the worst result in order to iron removal from silica which was not desirable. Finally 9 testes were carried out using spiral whish is the best gravitational separator for elimination of iron impurities from silica. The best result of spiral tests were achieved on scrubber product. In this test concentrate weight percent and its Fe2O3 grade were 82.32 per cent and 0.085 per cent respectively. Finally a test was carried out using 2 stages of spiral in order to develop flow sheet. In this test concentrate weight percent and its Fe2O3 grade were 78.8 per cent and 0.1 per cent respectively. This product can be used to produce float (clear flat) glass.

Sep 13, 2010

By Wilson AF

Gold-silver mineralization at Cracow and Ukalunda in Queensland comprise quartz-filled veins, fissures and breccia zones hosted by propylitically altered volcanics and epizonal intrusions which are strongly fractured. The terrestrial volcanic facies, structural setting, type of alteration and complex mineralogy suggest these deposits are of the epithermal type.The 180 depleted character of the wall-rocks is consistent with the involvement of meteoric waters in convective hydrothermal cells associated with the vulcanism. The Cracow quartzes have remarkably low 6180 values from -2.0 to -3.4 per mil typical. of meteoric hydrothermal systems at high latitude, consistent with the inferred position of Australia during the Permian. 6180 values for the Ukalunda quartzes exhibit a wide range from 5.1 to 14.9 per mil which reflect the mixing of magmatic and meteoric waters, and a steep geothermal gradient.Further stable isotope and geochemical studies are in progress to establish the scale and morphology of the zones of anomalous 6180 and mineralogy in the wallrocks which constitute significant exploration targets.

Jan 1, 1984

A mining companyÆs approach to managing the risk of theft of explosives and initiating devices should be underpinned by an organisation-wide policy developed with internal and external consultation. It should be based on the principles of sound proactive risk management, planning, monitoring and remedial action. This paper aims to provide mining (and construction)organisations with the rationale and many of the tools they need to control explosive security risks. As with all legislative compliance, they are best managed by incorporating the statutory and legal requirements into company policies, management systems and plans, operating procedures and culture. This is the approach that has been adopted in this paper. Trends we should expect: more prescriptive legislation and stricter government regulations; enhanced enforcement and more prosecution; more sophisticated detection systems, eg airports; additional compliance costs; additional vigilance on record keeping; improved risk awareness and risk communication; wider use of explosives policies, management systems and plans; and additional security staff with investigative skills.It should be noted that mining companies will be required to play their part in reducing the likelihood of explosives, intended for mining purposes, being wrongfully used to threaten, hold to ransom or to injure individuals or members of the public or to produce property damage. This will be done by putting in place safeguards to reduce the risk of theft of explosives while they are under their control. On that basis, this is a business risk assessment rather than a hazard risk assessment. A conclusion of this paper is that mining companies can and should play their part in reducing the supply of explosive materials that can then be used for illegal activities. In fact, mining companies have always had this duty, but now the stakes are higher û æcomplacency no longerÆ.

Jan 1, 2004

By M Byrne, P Newman, M Lindqvist

SomincorÆs Neves Corvo Mine, one of the largest copper producers in Europe, is currently constructing a paste backfill plant in order to replace cemented rockfill in its bench and fill stopes and possibly replace hydraulic sandfill in the drift and fill stopes. A 250 m flow loop was constructed at the mine and the flow properties of various paste blends were investigated. Cycloned tailings and total tailings were both pumped successfully as pastes and were also combined with waste rock for additional testing. The pressure losses in 102 mm and 154 mm diameter pipeline were recorded at flowrates up to 60 m3/hr and are presented at slumps from 120 mm to 250 mm. The data showed the sensitivity of paste mixtures to slight changes in consistency, confirming the need for accurate control during paste production and distribution. The flow results clearly showed the different paste behaviour between cycloned and total tailings pastes and the change in properties at low and high slumps. In addition to pressure loss data, strength testing was done on 38 mm and 82 mm diameter samples. Further strength testing is ongoing at the mine using fly ash as a supplement to cement, reducing the overall binder cost. Preliminary engineering for the underground distribution system is briefly discussed, with reference to the siting of the plant. The Neves Corvo Mine is particularly shallow and alternative methods to pumping were sought in order to ensure sufficient hydraulic head for underground distribution. The comparison of options had to take into account the capital and operating costs, the operation of the plant and the impact on the future expansion of paste fill utilisation at Neves Corvo.

Jan 1, 1998

By D S. Perera, P Wal, D C. Southam, J L. Lowe

The Cooperative Research Centre for Sustainable Resource Processing (CSRP) is undertaking a large research project involving partners from industry, universities and government, which aims to develop the necessary chemical and structural understanding of geopolymer materials made from waste products for them to be used to capture a significant market share of the concrete business for a given industrial region. We are investigating the suitability of a range of soluble silica-bearing waste streams for use as geopolymer concrete feedstocks. In order to utilise a variety of waste streams, either singly or blended, an understanding of the role of secondary metal ions (Fe, Ca, Mg, Ti, etc) in the geopolymerisation process is essential. A range of experimental and analytical techniques is therefore being used to better understand the structure-chemistry-property relationships of geopolymers. Currently, we are investigating geopolymers made from a variety of waste streams (fly ash, kaolinite, red mud, etc) available in the Kwinana Industrial Region, Western Australia. This paper will detail how the basic scientific research underpinning the project is vital if waste streams of varying composition are to be successfully used in a commercial concrete product and the regional synergies required to develop geopolymers from waste streams.

Jan 1, 2006

For the last 4 years political leaders have found a new subject on which they can safely generalize wihout creating opposition. That sub- ject is commodity prices. Since the four-fold increase in OPEC crude oil prices, public atten- tion has focussed as never before on the subject of commodity prices. To advocate stabilizing com- modity prices is akin to supporting motherhood or peace or better schooling. Everyone gives lip service to the concept that stable commodity prices are desirable. It is easier to state the principle than to achieve it. Prices that are stable in terms of one currency may be clearly unstable in terms of a different currency. This has become a troublesome matter since 1971, when the world's leading trading currencies were set free to float in relation to each other. To illustrate: consider copper prices in the interval between the end of 1974 and the end of 1977. During those 3 years, the copper price in pounds sterling on the London Metal Exchange rose by 25 per cent. During that period, however, in terms of the USA dollar equivalent, the price was unchanged. And during that period, in terms of the German mark equivalent the price shrank by 13 per cent while the Japanese yen equivalent f.11 1k

Jan 1, 1978

By Mahony BK

This paper discusses the major infrastructure elements required to support a typical Australian mining development. Infrastructure elements are grouped into four major types, urban planning, transportation, power and communications and water supply. The design criteria applying to individual elements within these groups are briefly discussed as well as order of magnitude cost estimates. The use of simulation models to test the capacity of existing rail networks, as well as novel sources of energy generation, are also described.

Jan 1, 1983

For an exploration area with a predetermined grid of data points, a construction is given for elementary blocks which subdivide the entire area without omission or overlap, and with the property that each data point is situated at the centre of its corresponding block. The construction has a useful optimal property, and more importantly avoids an error which has been made recently in more than one publication.

Jan 1, 1985

FOR some years after the erection of the first chlorination plant at Mount Morgan the ore sent to the works for treatment was mined entirely from the oxidized zone; consequently, the bullion recovered at the refinery was of unusual purity, averaging about 972 in fineness, and, as no impurity in any way detrimental to the softness or toughness of the bullion was present, there was no necessity to subject it to any refining process.The charcoal from the filters was calcined to ash in small reverberatory furnaces of the usual type. The ash was mixed with suitable proportions of soda and borax to form a good liquid slag. This' mixture was then charged into salamander cruciblesand run to metal and slag in the ordinary wind furnaces-a slow and tedious proceeding in the Mount Morgan climate. The bullion, cleaned of slag, was re-melted under borax and poured into bars weighing from 350 to 400 oz.; these bars, after being dipped while hot into dilute sulphuric acid, were packed and sent to the mint. Of late years, however, the ore coming from the deeper ground of the oxidized zone became much lower in gold values, and contained variable but increasing quantities of sulphides, sulphates...

Jan 1, 1911

By A D. Bugarski, G H. Schnakenberg Jr

An investigation was carried out at a US underground mine to characterise diesel aerosols and to asses the effects of various control technologies on the concentrations and properties of particulate matter and gases emitted by heavy-duty diesel-powered equipment. This study was dedicated to evaluating the impact on mine air quality of contemporary diesel particulate filter (DPF) systems installed on mining equipment. Additional efforts were made to assess the effect of blended biodiesel fuels, yellow grease and soy, ultra-low sulfur fuel, a fuel emulsion and of selected diesel oxidation catalysts on air quality and emissions. The carbon analysis performed on the collected samples showed that the tested DPF systems reduced the mass concentrations of elemental carbon in mine air by between 70 per cent and 92 per cent. In addition, TEOM measurements, collected during these tests, showed that the total diesel particulate matter concentration in the mine air was reduced by greater than 65 per cent when DPF systems were used. The tested biodiesel blends were found to reduce elemental carbon concentrations in the mine air by between 49 per cent and 33 per cent, for the B20 (20 per cent biodiesel/80 per cent #2 diesel) of soy and yellow grease respectively and between 66 per cent and 56 per cent for the B50 (50 per cent biodiesel/50 per cent #2 diesel) of soy and yellow grease, respectively. The water-in-diesel fuel emulsion was shown to reduce elemental carbon concentrations by as much as 85 per cent. NO2 measurements showed an increase in the maximum concentrations of NO2 when catalysed DPF systems were used instead of mufflers.

Jan 1, 2005

By M Wortley, J McKay, D La Rosa, O Guyo

It has been a generally held concept that crushing operations were, by their nature, too simple to benefit from the implementation of advanced process control. The commissioning of an OCS¬ expert control system and image-based oversize detection system, VisioRock, at the Pilbara Iron Tom Price facility are dispelling these notions. A constraint-based OCS¬ expert control system has been designed and commissioned on the high-grade crushing and screening plant along with a vision-based oversize detection system functioning on six product conveyor belts. To date, the expert control has demonstrated the ability to increase production by maximising dynamic constraint utilisation. Dynamic constraint utilisation is a concept developed by Rio Tinto Technical Services for effectively evaluating constraint-based control logic performance. The VisioRock system has been installed and configured and has been operating for a period of several months. Currently, Tom Price and Metso personnel are working to define correct oversize detection thresholds. Details of the plant implementation are discussed.

Jan 1, 2005