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By Y Li, L Zhang, G Li, S C. Dominy

Qiagong skarn iron (copper) deposit is located in Xietongmen County of Tibet, China (N 29¦52Æ14.9ö, E 88¦24Æ10.3ö). It is situated at the middle-western Gangdese porphyry copper-belt. Mineralisation is related to a Himalayan porphyry intrusion, with the mineralised body occurring at the contact zone between the Tertiary Takena Formation carbonate rocks and Himalayan monzonitic granite porphyry. The melt, melt-fluid and fluid inclusions were observed in early quartz, with most abundant fluid inclusions in quartz, calcite and garnet from the skarn. The geology and inclusion assemblage show a close relationship between iron (copper) mineralisation and a Himalayan porphyry intrusion. Based on preliminary inclusion studies, this paper discussed the characteristics, evolution of ore-forming fluid and affiliation to the Himalayan porphyry intrusion. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

To obtain the best economic results in treating the comparatively high-grade ore of the Kalgurli Mine a good roast is essential, and the effort of this paper will be to briefly describe the plant and the conditions prevailing in roasting, which, on an output of about 360 tons daily, subsequently enable an average extraction of slightly over 94% of the gold to be maintained.The percentage of sulphur in the ore varies between 2'5 and 3'5, the lower figure existing when treating oxidized ore. The average gold value is 13 dwt; this occurs chiefly as sylvanite, containing .a lower percentage of silver than is usually present in that mineral. One ore body in the mine contains hessite (Ag2Te) in considerable quantity, associated with gold telluride, and when ore from this stope is being treated the silver contents rise to as high as 20 dwt, but the usual amount is about 9 dwt. per ton, of which only a small proportion is extracted. Other metallic minerals, in addition to pyrite, occurring more or less commonly, are arsenopyrite, magnetite, chalcopyrite, and the tellurides calaverite (AuTez)and coloradoite HgzTe3). A small proportion only of the value occurs as free gold.

Jan 1, 1911

South Africa is the world's largest producer of gold. The survival of its gold mining industry is dependent, to a large extent, on the successful implementation of new mining technology which reduces the operating costs. Gold mines of the country have a record of a high operational cost per tonne of rock excavated. The geology of the gold-bearing rock, in addition to the mining depth and the gold recoverable grade, profoundly affect the profitability of the industry. Among the other mining operations, drilling and blasting take a fair share of the mining cost. It is therefore proper to implement a dynamic approach of technological review aimed at combating the escalation of mining costs. Over the years, the industry has moved away from labour intensive activities. Mechanised operations are introduced where possible. Management techniques are oriented more towards better utilisation of human resources and machinery so as to enhance productivity in the stopes. This paper addresses the issue with particular reference to blasting operations in the stopes of deep gold mines. It reviews the conventional drilling and blasting techniques. It outlines some innovative changes brought about in the course of recent years with the aim of optimising productivity and the stope efficiency in particular. It focusses on the peculiarities of the blasting technology in deep mines. It discusses the issue of interaction between the high stress fields underground and the blasting generated stresses on rock fragmentation, as well as their impact on the remaining excavations. It anticipates the concept of the new technology of selective blasting in stoping. Finally it puts forward the crucial role played by management of the human factor underground.

Jan 1, 1995

By Hoskings AD

Bolting forms a prestressed elastic layer of rock which is capable of supporting loads at right angles to the bolted surface. Investigations on rock bolting made with a number of different models give rise to empirical and theoretical prin- ciples for the formation and action of the layer. In the models, flat and arched layers of many materials were used simulating rock conditions ranging from closely interlocked blocks to fragments of various shapes. Results of observations made in the underground works of the Snowy Mountains Scheme are related to the mode of action of bolted surface layers of rock. There is abundant experimental, theoretical and practical explanation for the well-demonstrated capability of bolting as a means of rock support.

Jan 1, 1971

By Horowitz F. G, Lamb P

As mining operations become larger and more complex, larger volumes of geological, geophysical, and production data must be manipulated and interpreted on a day-to-day basis. Because of the large volume of data, more sophisticated data storage strategies, interpretation tools, and visualisation tools must be used by exploration and mining operations in order to remain competitive. Critical to better practice is an understanding of the basic syntax and character of geological and mining data, expressed in the form of a data model. In the short-term, a data model can be used to implement or evaluate schemes for data storage or exchange. It can be used to evaluate software. In the longer term, a data model is essential to the design of the next generation of software for 3D geological modelling. In this and the related paper (Lin et al, 1995) the data model in use by CSIRO is presented, together with: 1. examples of the use of data transfer in the linkage of existing mining software; and 2. examples of the use of the data model in software design.

Jan 1, 1995

By A Tomsett, J Rutter

Ore control systems at Ridgeway have been designed to deliver gold and copper metal production through focussing on the ore characteristics that impact on mine and mill performance and ultimately metal delivery. This is achieved using data collection and management systems which allow data to be collected digitally with æat captureÆ validation routines. This data forms the basis of forecasting systems which aim to accurately assess local in situ and drawn ore characteristics. Physical attributes of ore such as draw characteristics, brow conditions and visual grade estimation are rountinely recorded. Ore tracking and accounting systems monitor gold and copper grade, copper mineralogy, host lithology and ore sizing. These have material impacts on concentrator throughput and metal recovery. Routine reconcilation and check sampling allow calibration of these systems.

Jan 1, 2002

The current quantity of rejects from coal beneficiation in Australia represents 20 to 25% of raw black coal production. Approximately 80% of the rejects are derived from coarse processing for particles in the 200mm to 0.5mm size range. The safe and enviornmentally acceptable storage of coarse coal rejects is of interest to coal mining companies. Additional public benefit would be derived from the utilisation of a waste product as a source of fill material for civil and mining engineering applications. BHP Engineering has taken a leading role in the design for storage and utilisation of coarse rejects from two mines associated with the Broken Hill Proprietary Conipany Ltd. The tailings dam at Stockton Borehole Colliery (N.S.W.) is to be raised and a study by BHP Engineering has shown that coarse rejects are suitable for the formation of the supporting embankment surrounding a compacted clay core. Transportation and storage of coarse rejects at the Thiess Dampier Mitsui Riverside Mine (Moranbah, Qld) is achieved by a conveyor leading directly from the coal preparation plant to a discharge stacker on the crest of the rejects stockpile. Production of coarse rejects was higher than anticipated for the initial dump design. BHP Engineering has completed a review of dump design with emphasis on safe operating conditions for the conveyors and stacker system. Data on the geotechnical properties of coarse rejects from Australian coal mines are presented. Coarse coal rejects are a material which should not be considered as waste, but as a potentially valuable resource for many future applications. Appropriate engineering design for the storage and utilisation of coarse rejects would result in an improved environment and economic benefits for the Community.

Jan 1, 1987

By Singh T, Singh D. P

India has limited resources of coking coal. Most of the coking coal seams are located in Jharia Coalfield. These seams were worked in the past by the bord and pillar system in a haphazard manner, which has resulted in honeycombs of old working. Most of such areas are under fire. In order to meet the demand of coking coal in the 21st century, it is essential that the coal locked due to old underground workings is recovered fully by conducting opencast mining to an ultimate depth of 500 m. The major problem envisaged in conducting opencast mining in such areas will be the stability of pit slopes over voids and the behaviour of subsided material in the pit slopes. An attempt has been made to simulate this complex situation from a specific section of the rockmass of a mine in an equivalent material (EM) model. The old workings existing in upper coal seam (V) were simulated by developing staggered bord and pillar workings in two sections and depillaring them. Opencast mining was conducted for recovery of coal locked due to irregular working in coal seam V. The slope instability caused by intersection of the slope with the void, during frontal working (by shovel-dumper combination) was observed in various situations. In this paper, the technique adopted for simulation of a 125 m thick section of rockmass in an EM model is outlined. Adverse effects of staggered workings and

Jan 1, 1988

The role of metals in the economy is discussed with regard to the flow of metals through to final demand and is illustrated by data for seven metals. Factors influencing the changing pattern of metal consumption are described, including relative prices. A des- cription and discussion of current metal demand forecasting methodologies precedes a discussion firstly of broad economic trends and secondly of the evolving pattern of metal consumption relative to GDP (metal consumption intensity), as technology and other factors change and as economies mature. The tendency for metal consumption intensity to plateau and decline when economies reach a certain region of per capita GDP, following a rapid rise early in the industrial- ization process, is shown in comparative data for seven metals and six countries.

Jan 1, 1979

As a result of cheap Maui gas and plentiful hydro-electricity, over the past few decades New Zealand has enjoyed some of the cheapest energy of any OECD country. The situation is changing; at best we are facing some radical changes in energy use, at worst we are facing a crisis resulting from the following:   Cause 1: Maui gas will be exhausted by 2012. Distorted pricing and supply contracts; resulted in Huntly Power Station, a coal mine mouth generator running on 70 per cent Maui gas until very recently!   Cause 2: Investment in new generating capacity (and transmission) is woefully inadequate; as a result hydro lake levels are being continually pushed to the limits.   Cause 3: Distorted thinking is everywhere, for example; æWe will find more cheap gasÆ. æGas is clean û coal is dirtyÆ. Hot air  û ægreen alternatives such as wind generation will save usÆ. æNo NuclearÆ. The outcomes of the distorted thinking will be price increases, then shortages (there is nothing like "black-outs" to focus national thinking) and finally recession.   But what can NZ do? - Mine Coal. Coal jump-started the industrial revolution, it can provide the transition to post-gas and oil. NZ has the second highest reserves of coal per capita in the world, yet we use less that any other country with significant coal reserves. Our exports of our best coal have increased threefold, yet out own consumption has remained static at about 1-1.5 Mtpa for the last 30 years. Our coal is NZ owned and inexpensive relative to other energy sources, even allowing for infrastructure and environmental costs.   What can we do? We as mining professionals can promote informed responsible development and investment in the country's mining and energy business. We can galvanise public opinion on issues such as æunbundlingÆ our entire energy chain from mine-to generator-through transmission, even if the nuclear issue has to wait! With oil above US$70/bbl substitution is feasible. For individuals, there is always solar!

Jan 1, 2006

By Seib W

In cut-and-break rock excavation use is made of the fact that breaking rock in tension towards a free face requires a specific energy of excavation which is small in comparison with that required for rock excavation using conventional tools operating by a process of indentation of the rock.The process of cut-and-break excavation comprises firstly a cutting step in which a groove is cut into the rock surface, followed by a breaking phase in which a tool is inserted into the cut in order to break the rock adjacent to the cut.

Jan 1, 1992

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

Australia contains a variety of iron ores, differing in grade, chemistry, size distribution and genesis. While a proportion of this ore is used world-wide as blast furnace lump, much of the material mined is high grade fines, requiring agglomeration (usually sintering) before blast furnace reduction. Sintering studies initially concentrated on the production of ferrous material of high iron content, coarse size and sufficient cold strength. In recent years research involving pilot plant sintering, precise test procedures and mineralogical analyses has focussed on the additional sinter properties of hot strength and reducibility. Aspects of mineralogical studies applied to iron ore sintering are described.

Jan 1, 1989

By McKenzie C, Michaux S

Modern quarrying operations focus attention on blasting operations as a critical component in the overall cost-effectiveness of quarrying. Generally, optimisation of blasting has been linked to the processes of drilling, explosive consumption, secondary breakage, and product haulage to the primary crusher. This approach gives no consideration to the impact of primary crusher feed size distribution on downstream processes, or on the quality (ie shape and strength) of the final product. Blasting operations can be manipulated to produce a wide range of muckpile size distribution. This paper presents the results of studies into the impact of muckpile fragmentation on downstream crushing and screening operations, and includes measurements of primary blast oversize and muckpile fragmentation, together with measurements of size distribution, circulating loads and flakiness for various process streams throughout a quarry processing plant. This paper is an extension of other studies investigating the prediction and control of fragmentation from blasting, and the role of explosive performance in controlling muckpile fragmentation.

Jan 1, 1995

By R E. Conder

A major initial and ongoing cost component in many mining operations is that of transporting mined materials and processed ore from the point of extraction or processing to the next operation. For various reasons the transport distance can be significant or in some cases the route may be particularly challenging. The trend to higher production rates to gain economy of scale benefits and capitalise on sales opportunities means that optimisation of transport can play a significant part in profitability. Apart from the cost criteria, increasingly there are other criteria such as environmental restraints, land ownership and security of supply that can have a significant impact on determination of the optimum route and transport vehicle. The paper aims to briefly highlight the important selection criteria and the benefits and disadvantages of the most commonly utilised transport vehicles. It then moves on to looking in more depth at belt conveying, highlighting the unique capabilities of the Metso MRC Cable Belt Conveyor system.

Jan 1, 2004

By Vidalinc, Raffoux

Longwall faces producing in the order of 20,000 tons per day of raw coal are presently running in the Houilleres du Bassin de Lorraine of Charbonnages de France. Production levels of twice that level pose some technical and economic problems of coal cutting, ventilation, coal and equipment transportation in the.face and from the face to the sur- face. The peak productions of the equipment in use today, the results of trials with new equipment, the utili- sation of forecasting models (some in the form of software), allow us to fo- resee feasable technical solutions to these problems. They will first be considered in the best possible context (thick- ness, dip, non gassy, soft coal, good strata, no faults). This will give. the necessary conditions to reach daily output'of that level. A sensitivity analysis of these- figures to the effective natural con- ditions will then be undertaken and the implication of such a project on health and safety (dust, climate ...) will be carefully considered. A concise technical and econo- mical approach will permit us to fore- cast the economical interferences of such production units and specially the consequences of sudden variations of the output (downtimes, failures, etc). From this investigation, goals for technological development and re- search areas will be outlined to be able to reach this production target in the XXIst century.

Jan 1, 1988

By Peng S. S

Measurement of pressure distribution under the base plate of the Hemscheidt 2-leg 800-ton shield was performed underground for two shifts using 12 pressure cells installed in two rows, one each under each split base plate. Pressure distribution was uneven depending on contact condition. In general the highest base pressure occurred at 1/3 of the base plate contact length from the rear edge. The resultant was near vertical, and the pressure under the tail side split base plate was always higher than the head side. For comparison, pressure distribution on the canopy and under the base plate was also measured under controlled conditions at the USBM's Mine Simulator Testing Facilities in Pittsburgh, PA. A total of 45 tests were conducted under several simulated contact conditions. The results showed that the actual contact area is highly dependent on the compliance of the immediate roof and floor due to the sloped canopy tip and a base lifting device under the base tip. The loading distribution tends to change in magnitude and profile as the leg pressure increases. The base lifting device exaggerates the high toe loading on the base plate characteristics of this type of shield support.

Jan 1, 1992

Metsim is proving to be a powerful tool when designing a heap leach operation. The most useful outputs arc determining the fluctuations in pregnant solution recovery rate, make-up water rate, gold recovery rate. and pond levels. Detailed data are needed for input: a pad loading schedule, a mining rate schedule for each ore type, column leach test data for each ore type, column tests on water dynamics (ie hourly flow-out versus-in during saturation and drain-down), monthly rainfall and evaporation data, and proposed pond dimensions. These data allow 'what if' studies on application rates, leach rates, loading rates and other variables of interest. Examples will he given of modelling both a rectangular pad and a valley fill operation.

Jan 1, 1994

By J Zhou, X Bi, Y Yan, W Peng, H Yang, D Weng, P Li

Fortescue Metals Group (FMG) fines from Western Australia is a hematite and limonite mix characterised by high crystal water content. Due to its higher supply capacity and lower prices, the Wuhan Iron and Steel Corporation (Group) intended to use more FMG fines in the sinter mix. It is understood that sinter quality is closely related to its microstructure featured by the hardness and brittleness of different mineral phases, the content of micro pores, and trans-cracks. In order to maintain sinter qualities such as tumble index, reducibility and so on at higher FMG fines blend ratios, a research project was initiated to study the effects of the FMG fines blending ratio on sinter microstructure. Research results showed that at higher FMG fines ratios, the hardness of hematite and magnetite were both decreased while the hardness of calcium ferrite showed a tendency to decrease. The number of cracks that were generated during Vickers hardness measurement in various mineral phases decreased, but their length was shortened, and the variation of crack lengths increased. The contents of hematite and magnetite were also reduced and the reduction of magnetite was clearer. Also the content of calcium ferrite and pores rose and the magnitude of the increase of pores was greater. Among all the mineral phases in sinter cakes, the Vickers hardness of hematite was highest within the range of 879 N/mm2 ~ 942 N/mm2, and therefore the decrease of its content in sinter and the enhancement of its brittleness, ie the number of cracks increased, were harmful to sinter strength. In addition, the excessive increase in pores content is also not favourable to sinter strength.CITATION:Bi, X, Yan, Y, Zhou, J, Peng, W, Li, P, Yang, H and Weng, D, 2013. Study of sinter microstructure with various blend ratios of Fortescue Metals Group fines, in Proceedings Iron Ore 2013 , pp 331-336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Tronson K

Improvements in technology do not necessarily lead to higher profits: the benefit of lower costs can be captured by coal buyers, governments and workforce rather than by the colliery operators. The economic impact of longwall mining in Australia has been critically assessed to provide lessons for the future. For a variety of reasons, companies investing in longwall equipment in the past five years have generally not achieved an adequate return on the funds invested. The effect of technological innovation must be examined in the light of competitive forces operating in the market. Projections of cost reduction trends in the coal industry have been applied to a world cost model to provide a picture of the coal industry in the year 2000.

Jan 1, 1988