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By Sinha DK

Coal Mining in India had been confined in the past primarily to two or three coalfields. Unscientific mining has led to huge degradation of land including massive subsidence of strata and disturbances of water tables to a wide extent. This has caused problems not only in flooding of mines from surface water but also in further planning of the surface drainage for current mining activities. Now, therefore, surface hydrology and land-use potentialities of the area have been endangered inflicting severe damage to the overall environment and ecology of the area. The paper Discusses certain investigative aspects of the problems highlighted as above in one of the coalfields, and encompasses mainly the following areas : 1) Quantitative estimation of the damage already done to the natural surface drainage system. For this purpose damage to topography and drainage for the last fifty years have been made out through the aerial photographs and topographic map sheets 2) Analysis and comparison of different states of such photographs are carried through to indicate the extent of damage to the hydrological conditions inducing undesirable changes in its land-use pattern. Based on the analysis, concrete suggestions are made to restore the water drainage system which will be most suitable for future mining in the area containing high grade coal. The design and planning of the drainage system is based on the total system approach including the cost benefit analysis as well as hydrological considerations.

Jan 1, 1988

By C Aldrich

In this paper, the use of topology preserving projections (Sammon maps) and neural networks are considered as a basis for the construction of multivariate statistical process control charts for a semi-autogenous grinding circuit on a gold plant. Comminution circuits are often operated in a quasi-steady state mode, where the mills tend to move rapidly from one state to another. This makes them difficult to monitor by conventional means designed for continuous steady state processes. As a first step, process data reflecting normal operating conditions are mapped with SammonÆs algorithm. Only one feature is extracted at a time and each mapping is captured by a neural network model to allow online application. Reverse neural network models are used to reconstruct the data prior to the extraction of subsequent features from the data residuals. The ensemble of neural network models can then be used for both fault detection and identification. The approach compared favourable with both linear and non-linear principal component models. It was able to detect two simulated fault conditions both with a reliability of 100 per cent, as opposed to 57.8 per cent and 95.2 per cent detected by an approach based on the use of linear principal component analysis and 84.1 per cent and 98.0 per cent detected by an approach based on non-linear principal components extracted with auto-associative neural networks.

Jan 1, 2007

Fluid inclusions and sulfur isotopic compositions were studied in a possible extension of the Toyoha polymetallic vein deposit. The objective of this work was to gain a better understanding of the ore depositional conditions, sources of ore constituents, and distribution of mineralizing fluid in the region. Fluid inclusions in sphalerite and quartz show that most homogenization temperatures range between 190¦ and 290¦C. Most salinities range from 0.0 to 3.4 wt per cent NaCl equiv. Sulfur isotopic compositions of ore minerals (pyrite, sphalerite and galena), determined by a conventional technique, range between 1.3 and 7.7 per mil. The mineralizing fluids were characterized by relatively low and various temperatures and low to moderate salinities compared to those at the southeast region of the main ore bodies (Izumo and Shinano veins) where rare elements such as tin, tungsten and indium occurred. Obtained temperatures and salinities were attributed to the mixing of hydrothermal fluids with groundwater. Sulfur isotopic data suggest sulfide sulfur was of magmatic origin. Isotopic temperatures, estimated from the isotopic fractionation factor between sphalerite and coexisting galena, are between 195¦ and 322¦C. The temperatures are only consistent with fluid inclusion homogenization temperatures in sphalerite or coexisting quartz when sphalerite was a honey-yellow coarse crystal lacking conspicuous colored growth bands. This suggests the detailed classification of mineral pairs growth textures will be necessary for precise in situ measurements to obtain reasonable eothermometric results.

Jan 1, 2002

THIS instrument, depends on the principle that, over a short period, the surfaee of a porous substance from which a liquid is evaporating receives the same amount of heat by conduction, convection, and radiation as it loses in the latent heat of the evaporating liquid. If, then, the amount of heat being received by a surface can be measured, the rate of evaporation can also be obtained. The Kata thermometer is also based on this principle differently applied.The instrument, as shown in Fig. 1, consists essentially of a thermometer with a sliding which is divided by three pointers into two equal parts which may be spaced so as to cover a distance of, for example, 5° of the thermometer scale. The instrument is calibrated so that the amount of heat required per unit area of the bulb to raise the menissus is known. The method of using the instrument is as follows:The slide is first set so that thc central pointer is at the temperature of the evaporating surface.The thermometer is cooled by any convenient means so that the meniscus is several below the lowest pointer. The thermometer is then placed near the evaporating surface, when the Ineniscus begins to rise and the time taken for it to rise from the lowest to the top pointer is measured. From this and the calibration results the amount of heat retained per unit area of the bulb at the mean temperature...

Jan 1, 1928

Timely disclosure of information germane to the taking of investment decisions makes an essential contribution to ensuring the growth, efficiency and integrity of our capital markets. It is a core contributor to the maintenance of fair, orderly and transparent markets. Australia has a strategic need to protect and enhance market integrity. Australia is ranked tenth in the Morgan Stanley Capital International (MSCI) World Index, yet represents only 1.59 per cent of that Index. In order to survive and grow in this globally competitive environment, Australian capital markets û the drivers for economic activity in Australia û need to attract foreign investment and engage retail capital. The communication of relevant and comprehensible information to the investor plays a vital part in fostering investor confidence, thereby building depth and liquidity in our market. We have had a rewarding partnership with the mining industry to develop and recognise reporting standards which could allow ready comparability and investor understanding of the mining investment vehicle. Our mining market has been successful because of the high standards of professionalism and the intellectual capital that has been built up among the participants û the mining professionals, brokers, analysts, mining investors, professional advisers and the market operator. The balance of knowledge and understanding among these participants combined with the competition for capital, contributes to the standards for our mining market in a way that the market operator simply cannot replicate by market rules alone.

Jan 1, 2002

The sharp deterioration in Au~tralia'S ternn of trade in recent years and the accumulating national debt highlight the need for a restructuring of the economy which is highly dependent upon primary agricultural and mineral commodity exports (figure 1). Table I gives an indication of the value that can be added to raw material by mineral processing. Significantly higher value is added through downstream manufacturing. In 1987, the mining and rural sectors accounted for 47010 and 38010 respectively of total exports valued at $35,782 million (figure 2). The export contribution from minerals comprised $12,266 mil- lion from unprocessed ores and concentrates and $4,668 million from metals and processed minerals including some simple manufactures. Coal accounted for 450/s of total primary mineral exports. Iron ore and alumina are other important mineral exports, while gold and aluminium are major metal exports. (Figure 3) Australia's minerals are now traded in a much more competi- tive and oversupplied market in contrast to the 1960's and 1970's period which was characterised by increasing exports of largely unprocessed ores and concentrates. Since the early 1980's (I cI) resscd )ver~cas nutrkcts and km rununodlity liriccs ha~c hcen the product of excess capacity installed to satisfy a forecast high growth in demand which never eventuated due to the world reces- sion. During this period the emphasis on technology development was focussed on reducing costs through increased production effi- ciencies in order to maintain competitiveness.

Jan 1, 1988

Dr. F. L. Stillwell. Segnit's article puts forward the views that the rocks associated with the Broken Hill lode are simply highly metamorphosed sediments, tbat metasomatism on a large scale was not an important factor at Broken Hill and that the rocks and lode were contemporaneously metamorphosed.In particular, the garnet quartzite, the most abundant rock in the limited section of the mine examined by Segnit, is described by him as a simple, metamorphosed manganiferous sediment.These views, while consonant with those of H. F. King (1958), are drastically opposed to those of myself and others e.g. Gustafson et al. (1950, p. 1383) who state that the most extensive hydrothermal alteration in the district is in and close to the zinc lodes in the Zinc Corporation and New Broken Hill Consolidated Ltd. mines. Segnit's conclusions conflict with 1. the absence of any manganiferous sediment in the Broken Hill district except in close proximity to the lode,2. the clear cut metasomatism of the dolerite dykes which indicates that the ore is younger than the dykes and therefore post-metamorphism, and 3. the petrofabric study of den Tex (1958) which provided independent evidence that the ore in its present form post-dates all events of a diastrophic nature in the area.The original sediments of the district were mudstones and calcareous sandstones with 2 to 5 per cent CaO. These have been converted by high grade metamorphism into sillimanite gneisses and quartzites characterized by the presence ...

Jan 1, 1962

By P J Savory

Ranger is a uranium mining operation located within one of the most environmentally sensitive regions of Australia. Geology has played an important role in mine planning, operations and rehabilitation since discovery of the deposits 25 years ago. The Ranger orebodies have a reserve total of 166 300 tonnes of U308 including 90 400 tonnes of U308 at North Ranger. At current milling rates these reserves give a mine life greater than 40 years. The uranium is hosted in Lower Proterozoic rocks of the Cahill I ormation and is associated with strong chlorite alteration. In pit grade control involves the use of calibrated probes and a radiometric truck discriminator allowing fast, accurate grade determination of material. Ore is defined at a cut-off grade of 0.2 per cent U308. Mineralised material is defined by the Uranium Mining (Environmental Control) Act 1979 (UMEC Act) at a grade of 0.02 per cent U30s. Natural water levels in the #1 Pit area vary as much as 7.5 metres between wet and dry seasons. Ground water inflow into the pit during the dry season is 600 m3/day. No significant slope failures have occurred in the pit. The environmental impact of mining operations is constantly monitored. Rehabilitation of non-mineralised stockpiles is ongoing. This paper discusses the interaction between geology, hydrogeology, rock mechanics and grade control with the present mining operation.

Jan 1, 1994

The equipment and general smelter layout for the Mount Isa Copper Smelter were designed by engineers associated with the American Smelting and Refining Company and by Mount Isa staff engineers. The final notice of site was dictated by the need for 'building the smelter near the existing Mount Isa power house to enable full use to be made of the steam from the waste heat boilers. Although much excavation work was necessary before concrete foundations could be poured, the location lends itself to further expansion should it become necessary. The plant is designed and constructed to involve straight line smelting operations which include the following major steps in the overall scheme.1. Charge make-up.2. Roasthig.3. Reverberatory smelting.4. Converting.5. Refining.6. Casting.CHARGE MAKE-UPA system of proportioning bins is provided for preparing the feed mixture for the roasters, Sulphide concentrate containing 24% copper wiil be delivered by belt conveyor from the filter plant to the smelter storage patio. This is a large roofed concrete floor that provides a maximum storage capacity of 8,000 tons of concentrate. Eight proportioning bins located below but adjacent to the south end of the patio will be used for actual charge make-up from which concentrate, ore and flux will be proportioned to the feed belt and conveyed to the roaster feed hoppers. Four of the proportioning bins, 80 tons capacity each, will receive...

Jan 1, 1953

At moderate depths this question is of relatively small importance, but at depths over 2,000 feet it becomes a matter of some consequence. The rate of increase of temperature with the depth varies in different localities, but as a rough average we may take it to be about 1° Fahr. for every 50 feet of depth. The variation of temperature of the earth's surface from summer to winter penetrates to a comparatively shallow depth. At 50 feet the variation becomes practically insensible, and the temperature of the strata will be about the mean temperature at the given locality, from 60° to 75° F. in this country or the comfort of men working in the mines it is desirable to maintain a temperature of about 70° F. in the workings, or approximately the temperature of the strata near the surface.In order to obtain some idea of the magnitude of the undertaking involved in cooling a mine, I have examined the effect of placing in a long drive an apparatus by means of which we can abstract heat at a uniform rate from the drive, keeping, thetemperature nearly the same at all points of the drive at any given time.The lowering of temperature 70 F. at any distance feet from the centre of the drive (treated as a cylinder of the same sectional area as the actual drive), after an interval of time days from the commencement of the operation is given by the formula...

Jan 1, 1907

On 15 August 1998 the first section of the PUTRA LRT system was opened to the public as a free service prior to official commencement of revenue service on 1 September 1998. It is a remarkable achievement to open a highly advanced medium capacity urban railway scheme in four years after the outline concept began. Even more remarkable is the implementation of the next stage which is the underground section planned to be operational in mid-1999. The decision to build the first underground railway in any major urban centre is a technical challenge. The PUTRA LRT System can be likened to Hong Kong when the initial MTR system began in the 1970s and Singapore MRT in the 1980s. Prior to the PUTRA railway very little bored tunnelling had been undertaken in Kuala Lumpur. A few shallow sewer tunnels had been built but the main experience of tunnelling in Malaysia had been for water, hydroelectric and road tunnels usually through granite formations. The ground conditions in Kuala Lumpur were known mainly from experience of piled foundations and occasional deep excavations. The suitability and likely difficulties to be experienced during bored tunnelling could only be theoretically predicted. In both Hong Kong and Singapore, government owned corporations were set up to implement the scheme, but in Kuala Lumpur the whole project has been undertaken by a private company PUTRA, a wholly owned subsidiary of Renong Berhad.

Jan 1, 1999

By P Nissen, T Jenke, M Ralph, M Cattani, M Quinlan

The West Australian Government hold an annual ‘Mines Safety Roadshow’ around the State’s regions and the capital city, Perth. Each year presenters provide an update on legislation and safetyrelated themes. A recurring theme is the mining industry fatality rate. Professor Michael Quinlan’s ‘Ten Pathways to Death and Disaster’ (Quinlan, 2014) has been referenced regularly to assist in structuring workshops and conversations concerning fatality prevention in the mining industry. The ‘Ten Pathways’ are the outcome of an analysis of fatal injuries in the mining industry, which identified a series of common themes to the fatalities: Pathway 1: Design, engineering, technical and maintenance flaws. Pathway 2: Prior warnings or causes for alarm ignored. Pathway 3: Failures in risk assessment. Pathway 4: Failures in management systems and hazard management plans. Pathway 5: Failures in auditing. Pathway 6: Economic pressures compromising safety. Pathway 7: Failures in regulatory oversight and inspection. Pathway 8: Worker and others expressing concern prior to the incident. Pathway 9: Poor management – worker communication and trust. Pathway 10: Emergency and rescue resources and procedures. To determine a fatality risk profile we asked participants at the Mines Safety Roadshows to indicate their perception of their employer’s performance in each of the Ten Pathways. We administered the questionnaire at the Mines Safety Roadshows in 2017, 2018, 2019 and 2023. In this paper, we report on the results of the questionnaires, and suggest how organisations can improve their fatality risk score.

Apr 16, 2024

By Lawson F

Arsenic-containing waste was dissolved into molten slags and the leaching behaviour of the quenched arsenic-doped slags (containing up to 2.3 wt per cent arsenic) was ascertained to evaluate the potential of this method as a means for arsenic disposal. The leaching behaviour was evaluated using acetic and sulphuric/nitric acid based solutions.From short-term (18 hour) leach tests, the amounts of arsenic in the leach solutions were found generally to decrease with an increase in the Fe(III)/Fe(total) ratio of the slag or an increase in pH of the leach solution. The amount of arsenic in solution increased with an increase in the slag basicity, the slag arsenic concentration or the surface area of the slag exposed to the leach solution. From longer term leach tests (up to 40 weeks) in the pH range 5 to 8, the arsenic remaining in the leach solution was believed to be controlled by sorption processes. The sorbent was an iron oxide-rich material which had the capacity to lower the arsenic concentration in the leach bottles to well below 1 ppm in some cases. At a leach solution pH over 9, the arsenic concentration in the solution increased with time, although the rate of solubilisation was much slower due to the high pH.Slags have the potential to stabilise arsenic and prevent it entering the environment provided attention is paid to the slag chemical composition and oxygen potential.

Jan 1, 1996

By Gente P, Eissen JP, Lafoy Y, Charlou JL

The North Fiji Basin (NFB) is delineated by the Vitiaz trench to the North (paleo sub duction zone, Brocher, 1985), the Vanuatu is- land arc (called before New Hebrides arc) to the West and South, the Hunter Fiacture Zone to the South-East and the Fiji islands to the East (Brocher, 1985 ; Larue et al., 1982 ; Carney and MacFarlane, 1982 ; Falvey, 1978). The NFB is characterized by shallow water depths (about 3 km) (Chase et al., 1982 ; Scla- ter et al., 1972 ; Karig, 1971), high heat flow (average of 2.29 HFC) (MacDonald et al., 1973 ; Halunen, 1979), strong positive free air anoma- lies (Worzel, 1965 ; Kogan, 1976 ; Luyendick et al., 1974 ; Solomon and Biehler, 1969) and a geoid anomaly (Malahoff and Larue, 1979) inter- preted as a geoid swelling. Few refraction data reveal a relatively thin crust and sediment co- ver, and the existence of low speeds in the up- per mantle beneath the NFB (between 7,1 and 7,7 km/s) (Larue et al., 1982 ; Raitt, 1956), which could indicate the existence of active spreading zone(s) in this area (Barazangi et al., 1974). Global seismicity of the SW Pacific clearly de- fines the.limits of the NFB, as well as the Lau basin (Sykes et al., 1969). But one can note the low level of shallow seismicity of the NFB (Ham- burger and Isacks, in press) which concentrates in three distinct trends :

Jan 1, 1987

The 1980's has seen a revolution in gold mine developments in Australasia. We are witnessing a near ten fold increase in all phases of gold mine development ranging from exploration through to production. Ounces produced have yet to mirror this activity but have increased from a low point of 600,000 in 1980 to 1,800,000 ounces in 1985 in Australia alone. In 1980 the region had less than 10 gold mines, yet 14 new mines started production in 1985 and as many as 28 might start up in the next 18 months. Developing gold mines in the 1980's in Australasia has not been the easiest of jobs, yet the great number of new developments suggest that we have entered a new era that will rank in history along with the 1850's, 1890's and 1930's as high points.Within- our Australasian region two very distinctive styles of gold deposits are being discovered and developed. On the Australian mainland the new mines are in geologically old rocks and are mostly the low grade haloes surrounding worked out high grade deposits. Most are limited life open pit operations depending on recent innovative carbon-in-pulp or heap leach technology. In the Pacific Islands region the style of discoveries are geologically recent, large bulk-low-grade deposits often geologically analogous to porphyry copper deposits. These deposits are typically 10 to 20 times larger than those being proved up on the Australian mainland.

Jan 1, 1986

Australia's gold mining industry has seen a resurgence in the past seven years - a resurgence the likes of which has been seen in very few, if any of this nation's other mineral industries. Industry experts are predicting that Australia could become one of the world's largest gold producers as the future of the South African gold industry looks increasingly tenuous under the present political crisis in that country. Therefore, it is utterly ludicrous for the Federal Government to introduce a tax which will see the Australian gold industry "wither on the vine."The Queensland State Government is utterly opposed to a tax on gold. Anyone in their right mind, who has seen the statistics could only agree with our stance. In 1984/85, activity in the gold mining industry is estimated to have accounted for over $750 million in national income, over$1,200 million in national output, and tax revenue of at least $115 million as well as providing more than 16,000 jobs. Chartered accountants Coopers and Lybrand's survey on the gold industry last year showed an increase in exploration expenditure by gold producers and explorers by up to 36% in 1986 from 1985 levels. That level is expected to be maintained in real terms for most of the remainder of the decade under the present tax arrangements. This is in contrast with the mining sector as a whole, where a recent Australian Mining Industry Council survey forecasted a 14% FALL in production.

Jan 1, 1986

The locality from where these specimens come is distant about 12 miles due south from the township of Bingara New South Wales, and is known locally as Carney's Reef, Barrack's Creek, Top Bingara. The formation traverses the western side of a serpentine spur from the main range, which runs through the country from the other side of Tamworth to Inverell, in the New England District. It has a due north and south trend, with an easterly underlay slightly out of the vertical. The formation has been opened up at different points for a distance of over two miles, and each place showing gold in the stone, and no place more than three to four chlins apart, the whole distance along the line of Reef being leased. The formation varies in thickness, the smallest being about 1 foot and the widest about 10 feet. The following is a list of properties, and description of work done on them at present. First south, and about one and a half miles from Hanion Brothers' old BalIarat claim due north, Court and patty hold a tenacre lease. The formation outcrops near the south boundary, and gold is obtainable in the stone. In the centre of the lease a costeen pit has cut the capping, which shows gold, and about two chains from the north boundary another one cuts the capping, also showing gold. The reef averages, where exposed on this property, 3 feet wide.

By Jin C, Shi X

The electrochemistry of leaching gold with thiosulphate has been studied systematically by using electrochemical techniques. Results show that the current peak of anodic dissolution of gold occurs at about 50 mV(SCE) and there is passivation in the polarisation curve in the thiosulphate solution in the absence of ammonia. Ammonia markedly improves the anodic dissolution rate of gold and reduces the passivation as well as making the current peak shift negatively. Results also show that there is no current peak for a cathodic process in the range of 0 -900 mV(SCE) in the thiosulphate solution in the presence of oxygen but absence of cupric ions and ammonia. In the solution containing 0. 1 mol/L cupric-ammonia ions, the peak occurs at about -400 mV (SCE) and the cathodic process is characteristic of a catalytic reaction. Oxygen presents a predominate effect on the cathodic process. Based on the electrochemical investigation, the following mechanism of leaching gold with ammoniacal thiosulphate has been proposed. Ammonia reacts primarily with gold ions on th anodic surface of gold and the formed A (NH3)2+ rea~s then with S2O 3 in solution to form the stabler Au(S203) 2 . Cu (NHS) 4 gains electrons on the cathodic surface and is reduced to CU(N) ? which is then oxidised by oxygen and regenerated into Cu(NH3) 4 after entering the solution.

Jan 1, 1993

By Allnutt S. L, Radojkovic A. M

Century, a major shale hosted zinc deposit in the Riversleigh Fold Zone of northwest Queensland's Mount Isa Basin, was discovered by CRA Exploration in 1989. A total of 322 drill holes, completed by the end of 1992, define a resource of 118 Mt of mineralisation averaging 10.2 per cent zinc, 1.5 per cent lead and 36 grams per tonne silver. Mineralisation is developed in the upper portion of Lawn Hill Formation Unit 4 (Pmh4). The intersection of the Termite Range and Little Range Faults, major regional structures, may have been important in controlling mineralisation development. Three listric normal faults, and an unconformity between Proterozoic rocks hosting mineralisation and overlying Cambrian carbonates, divide the deposit into three distinct blocks. The deposit is essentially blind, outcropping in only two places. The deposit is characterised by an extremely simple sulphide mineral assemblage, sphalerite being the most common sulphide phase. Pyrite, the most common phase in many other shale-hosted zinc-lead deposits, accounts for only five per cent of all sulphides present. Siderite is the principal non-sulphide phase present. Both sphalerite and galena have near stoichiometric compositions. Sulphides are confined to carbonaceous shale horizons. Intervening siltstones are essentially barren. Shale and siltstone beds forming the mineralised sequence can be correlated across the entire deposit area. Systematic grade variation occurs within each mineralised shale bed. Although sulphide laminae parallel primary lithologic layering, the point of most intense mineralisation development transgresses stratigraphy. Bituminous material is intimately associated with sulphide mineralisation.

Jan 1, 1993

By O Dahl, I M. Platten, E J. Sides

Many narrow-vein gold deposits are characterised by a high to extreme nugget effect and the presence of coarse gold. They rank amongst the most difficult of deposits to produce an accurate and precise resource estimate. This contribution presents a case study from the Nalunaq Gold Mine in Southern Greenland. The mine commenced operation in May 2004 and is currently operating at a rate of 400 tonnes per day, to produce about 100 000 oz gold per annum from a total resource base of 1.2 Moz. Mineralisation is characterised by quartz veins that are hosted within a shear zone that is continuous over about 1000 m. The principal orebody is the Main Vein structure, which ranges up to 3 m in width, maintains an average dip of 35¦SE, and contains significant gold grades (1000s g/t Au). Gold particles are often visible, with 25 per cent being greater than 250 microns in size. Variography using underground development samples indicates a nugget effect of about 75 per cent. For the 2005 resource estimate, a 2D metal accumulation ordinary kriged block model was used to produce a global grade for the Target and South Blocks of the Main Vein. Grade control chip-channel samples are collected from æshantyÆ drive footwalls, and used as the basis for both the kriged block model and to determine the grade of individual stope blocks by peripheral weighted averages. Geology plays a key role in mining efficiency, given the locally variable nature of the ore zone.

Jan 1, 2006