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By Dolan P

Various operating practices have been developed over many years to ensure safe and efficient production from the 1100 orebody. Some of these practices are described.

Jan 1, 1982

Rajasthan of western India blessed with rich base metal and phosphorite deposits. The biogeochemical and geobotanical methods of mineral exploration are greatly used in parts of Rajasthan Zawar, Khetri and Ambaj multi-metal project Gujarat and Jhamarkotra phosphorite deposit. These principles are exclusively based on certain assumptions about the anomalous chemical composition in plants and distribution and migration of indicator elements. Biogeochemical studies for lead zinc deposit of Zawar group of mines were carried out to locate the probable accumulators which could help in prospecting for these metals. The important roots of Impatiens balsamia plants contain 735 mg. of cadmium and crotolaria linifolia 603 mg., melhania futteyporensis 626 mg. lindenbergia muraria 443, celosiu argentia 360 mg. In the Khetri copper belt the vegetation is scanty and the species includes Acacia arabica, zyzypus jujuba and cactus euphorbia.

Jan 1, 1988

By S Z. Petho

The South Deep surface shaft system is being sunk to a final depth of 2750 m below surface and on completion will be the deepest single drop shaft in the world. The shafts will intersect the target reef horizon at 2650 m below surface. In order to negate the requirement for a shaft pillar, which would be extremely large at this depth, the reef horizon in the vicinity of the intersection is currently being mined. A high quality crushed waste/classified tailings backfill is being placed in the longwall stoping panels around the shaft intersection area. This will limit closure and ride which following shaft reef intersection could have a detrimental effect on the long term shaft stability. This paper discusses underground instrumentation results and numerical modelling exercises carried out to confirm that the shaft system will be stable throughout the life of the mine. Instrumentation projects include closure and ride measured between backfill paddocks and haulage leveling exercises carried out to determine the far field rockmass response to mining with stiff backfill. Results from the numerical modelling exercises show good correlation with measured data. This indicates that a high degree of confidence can be placed in the model input parameters and consequently in the design of the shafts to ensure their long-term stability.

Jan 1, 1998

The Pasminco mine at Rosebery in north western Tasmania is a medium sized underground base and precious metals mine. In April 1992 a major wedge failure of approximately 5000 t occurred in the backs of a main access drive to the 18 level H Lens orebody. This collapse prevented access to 190 000 t of ore which had been scheduled for production in July - August 1992. At the time of the collapse, the mine was in a transition period between mining small pillar remnants of several other orebodies and developing to the new deeper J Lens orebody.The development at this orebody was behind schedule and it was necessary to find a cost-effective and timely alternative to a 75 m bypass drive around the fall area.A Lysaght- Fletcher multiplate steel arch was available on-site from a deferred surface road project and it was decided to use this arch to regain access through the fall area. Due to the danger of continued minor falls, the entire 18 m long, 3.95 m high x 4.5 m wide tunnel had to be assembled in the 4.7 m wide x 5 m high accesss drive and pushed into the fall area as a single unit.

Jan 1, 1993

By Wilson R. G

The Bulli and Wongawilli Seams, the two principal sources of coking coal for the Port KKembla steelworks of Australian Iron and Steel Pty. Ltd., vary in rank and in type over the Southern and -South Western Coalfields. The Bulli Seam, ranging widely in type, produces coke varying from weak to strong. The Wongawilli Seam, more consistent in type, produces coke of more consistent strength, but considerably less strong than that from the best Bulli Seam coal. Plans of seam variation show the regional trends in rank and type for each sear. The strongest coke is derived from coal containing between 45 and 55 per cent vitrinite, m.m.f. This is obtainable from the Bulli Sean in a zone embracing Bulli and Appin Colleries.

Jan 1, 1969

By W Uhlmann, U Grnnewald, B Nixdorf

Flooding with surface water is the preferred technique for the abatement of acidification from pyrite oxidation in the lakes of abandoned Lusatian lignite mines. However, water resources of the region are limited and in addition, interruption of water inflow during the summer and the termination of the flooding process after reaching the final water level can lead to a re-acidification of the lakes. The development of three mining lakes with a surface-water flooding history of six to 28 years was analysed û in two lakes on the basis of fortnightly to monthly hydrochemical monitoring data. During summer flooding interruption, the younger lakes showed a decrease in pH from neutral down to pH 4. The degree of the pH decrease depended on the intensity of the groundwater inflow from the overburden dumps and this affected the hypolimnion more than the epilimnion. The third lake was flooded 28 years ago and up to now, interruption of the surface water inflow resulted in re-acidification. These three examples were able to show the benefits and limits of the surface water flooding technique for the abatement of Lusatian mining lake acidification.

Jan 1, 2003

Almost from the beginning of civilisation the inhabitants hadlearned the art of recovering and working copper to produceitems which were of use to society.From the early beginnings of the use of copper which can betraced back 6000 years and more, there has been an evolutionaryprocess accentuated in more recent times in which the art ofproducing alloys particularly with tin and latterly zinc and otherelements, has given society a wide range of useful alloys for usein industrial, domestic and architectural applications.

Jan 1, 1995

By J Slade, R Trueman

Unplanned dilution has the potential to seriously undermine the economic viability of a mine, and in some cases results in mine closure. The effect of stress damage on dilution has become increasingly relevant as mining depths increase. In the case of narrow vein mining, the incremental extraction of long-hole rings has the potential to result in a moving high stressed zone at the stope brow. This leads the hanging wall and footwall to experience a spike in the stress to strength ratios as the brow passes. In some cases, the stress to strength ratio may be high enough to result in fracturing or damage to the rock mass. The aim of the study described in this paper was to investigate whether stress damage results in a significant increase in dilution. The study involved analysis of overbreak from 410 case studies from the Kundana Gold mine in Western Australia. Site personnel had already undertaken calibration studies of the stress levels that result in rock mass damage. This calibration, in conjunction with numerical modelling showed that stress damaged stope walls at this mine had on average 50 per cent more overbreak than stope walls where stresses had not exceeded the damage criterion. For a design mining width of 1.5 metres, and with both walls impacted, this represents 36 per cent increase in dilution. After adjustment for possible sources of bias the difference reduced to an average 0.10 metres per stope wall, representing 13 per cent dilution for the mining width under consideration. The potential for stress damage related overbreak should therefore be considered as part of any assessment of narrow vein dilution.

Jan 1, 2005

By Woodcock JT

This paper deals with some innovations and current proposals for the treatment of gold ores and considers the possibilities of incorporating new developments in new or revised ore treatment flowsheets. The main topics considered are I. typical practice in relation to the size of gold particles, 2. concentration of coarse gold, 3. leaching reagents, 4. in situ leaching, 5. heap leaching, 6. carbon-in-pulp adsorption, and 7. treatment of complex ores (gold in pyrite, gold tellurides, and carbon-containing ores).

Jan 1, 1982

The deep seafloor in Papua New Guinea's proposed Exclusive Economic Zone appears to be a gold-rich province in the same sense as the territory above sea level. Two significant sites with polymetallic massive sulphide deposits forming today are known on neovolcanic ridges in the Manus Basin. Their high precious metal contents have led to renewed interest in the issue of exploiting seafloor mineral deposits. The prospects of finding other, possibly larger deposits in the region appear substantial. This paper reviews current data on seafloor deposits in Papua New Guinea (PNG) and raises some issues relating to future commercial exploration and mining of the sea floor. One of the known PNG deposits could become a prime candidate for the trials needed to develop technology, establish costs, and minimise environmental impact.

Jan 1, 1994

There exist many formulae for designing coal pillars. However, when applied to a given set of mining parameters, they lead to different pillar sizes and factors of safety. From the subsidence point of view, the pillars designed as protection pillars not only have to be stable, but also have to limit subsidence over them to a level acceptable to the structure being protected. The subsidence over a pillar of given width to height ratio depends upon the mining depth. A pillar may be stable, but the subsidence over it may be quite large and unacceptable for the structure. In many cases even though pillars may yield, they support the undermined strata and reduce surface subsidence. In addition, the yielding pillars eliminate peaks and troughs in the surface subsidence profile and reduce ground strains. In a given situation, whether a pillar yields or not depends primarily upon its width in relation to mining depth.

Jan 1, 1992

Authority to Prospect 57P lies within the Surat Basin',' an eastern lobe of the Great Artesian.Basin, a major Mesozoic . downwarp that,had its inception'in Triassic time. The northern edge of the Mesozoic Surat Basin overlaps the southern extension of the Bowen Basin, a 'major structure that warped do*nWard in varying degrees from Permian time into Early'Triassic time: The axis of the Bowen Basin may be superimposed on the axis'of a still older structure, the Tasman Geosyncline, that probably originated in Ordovician time culminating in Late Carboniferous time.Within. or bordering the area the geologic record 'clearly marks.major differences in the stratigraphy and structure related, to"the successive evolution of these three distinct structural units. Three major phases of sedimentation have been recognised; one related to the development of the Tasman Geosyncline froi'n. Devonian to.Early Permian time (Horton group), one related to-the development of the Bowen Basin from Early Permian to_Early Tri= assic time (Bowen group), and one related to the development of the Great Artesian Basin from Triassic to Cretaceous time (Great Artesian . Group).

Jan 1, 1962

Pbo activities have been measured in conventional blast furnace and direct smelting type slags at 1200¦C. Much higher activity coefficients than previously measured have been obtained and attributed to interactions between iron and lead oxides. The behaviour of PbO in the two types of slag reflects their relative silica contents. Simple equations derived from mathematical modelling work are presented for the prediction of Pbo activities in complex industrial slags.

Jan 1, 1984

Current problems in predicting sub-surface strata movement and fracture development due to longwall mining have highlighted the need for more accurate, dependable methods of physical modelling of rock mechanics problems which are beyond the capabilities of current mathematical techniques. Physical model studies of the caved zone above the working faces up to the base of a water source are of importance in attempting to understand changes in mass permeability due to induced fracture zones and the resulting ground water conditions. Turkey's most important supplies of coking coals are to be found within the hard coal resources of the Black Sea coast. Coal seams up to 9 metres thick, dipping at angles as steep as 90 degrees are being successfully mined at the Kozlu Mine. Since 1956, mining operations have been carried out under the sea in dry conditions. The undersea mining conditions of the Kozlu Mine have been investigated using scaled physical models constructed from artificial materials which satisfied necessary scaling requirements. Models representing the in-situ conditions were tested and the following extraction sequence was employed: 1. The Sulu Seam extraction 2. The Acilik Seam extraction (as two slices) 3. The Piric Seam extraction. The displacement of the fixed reference points were subsequently measured using a high precision photogrammetric technique and induced horizontal and vertical strains were calculated.

Jan 1, 1988

Drag pick roadheaders and continuous miners have been applied in the coal mining industry for several decades, having replaced drill-blast methods as the primary means of excavating coal and coal-measures strata. The generally harder rock types associated with metalliferous mining have precluded the use of such machines in the past, however, developments in machine technology and increasing labour costs and environmental constraints suggest that there are now likely to be applications suited to the method. Metalliferous mining engineers are generally unfamiliar with the machines themselves and with the fundamental criteria controlling rock cuttability. This paper gives an introduction to the machines and the controlling factors.

Jan 1, 1987

Scheduling the transformation of in situ coal to run of mine coal and its subsequent beneficiation to a saleable product involves the use of many `parameters' or `adjustment factors'. These include in situ density, moisture adjustments, mining

Jan 1, 1998

In December 1997, a series of new environmental legislation was enacted including:ò Environmental Planning andAssessmentAmendmentAct 1997; ò Contaminated Land ManagementAct 1997;ò Protection of the Environment (Operations) Act 1997; ò Native Vegetation Conservation Act 1997; andò Pollution Control (Load Based Licensing) Act 1997.These new Acts will have varying degrees of impact on the coal mining industry in New South Wales when they commence later this year.

Jan 1, 1998

Development of the Davcra flotation cell has continued over the past seven years. Preliminary testwork on single cells has now been extended to a com- plete Davcra flotation circuit, to cells ranging from 5 to 400 tons per hour capacity and to cells operating on a variety of materials. Operation of both test and production units has shown the Davcra cell to be competitive with conventional flotation machines. It offers a lower capital cost installation than conventional cells and in addition has a number of. operating advantages, particularly in its adaptability to automatic control.'

Jan 1, 1971

Applications of chlorine metallurgy to the extraction of metals often result in the production of volatile metallic chlorides, most of which condense directly to a solid phase at one atmosphere pressure. A stirred bed condenser suitable for th

Jan 1, 1980

By Marsham B, Baker D. C

The expansion of New Broken Hill Consolidated Limited (NBHC) concentrator necessitated the installation of hydrocyclone classifiers where rake classifiers had previously been used. Commissioning of the circuit and optimisation of circuit performance has highlighted problems related to classification of sulphide minerals. Testwork initiated to solve these problems has been used to develop cyclone models which have been incorporated in a ccnputer control strategy for the grinding circuit as a whole. The modifications to the circuit during the commissioning phase and the control philosophy are outlined.

Jan 1, 1983