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Problems caused by water discharge from surface mine ventilation shafts can be significant and are usually unforseen. The discharged water is often hyper-saline or acidic and can cause environmental degradation over a wide radius. It can also lead to recurring power pole fires and primary fan breakdowns. A range of solutions to the water discharge problem has been implemented in many Australian mines. In most cases the solutions have been ad hoc, with the overall cost and effectiveness varying tremendously. This paper reviews and contrasts the practicality and effectiveness of the various available remedial options.

Jan 1, 2002

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

Pressing-Drill Method - A Representative Method for Taking Analysis Samples from Recycled Materials

Sep 13, 2010

Size Separation Pretreatment and Alumina Recovery from Bayer Red Mud

Sep 13, 2010

Of late there have been various papers published on this subject by various authorities, in which certain definite factors influencing slime settlement have been brought forward. As the principles set forth by these writers are of great interest, and have, in most cases, been generally accepted, the author will review them in the hope that by discussion some more knowledge may be brought to bear on many points connected with the subject.The definition of slime at the present time is not a standard one, and varies according to different authorities, some defining slime as ore crushed to such a fineness that it will pass through a screen of standard size, say 150 or 200-mesh, in water (1, 2);others as that part of the finely-crushed material which is in the physical condition which causes it to remain in. suspension in water, and possesses pr?perties which render it almost unleachable (3). Authorities seem divided on this point, but of late American writers seem to prefer the former definition. On the contrary, B L Gardiner describes slime as a mixture of small particles of crushed ore of varying sizes which, when mixed with water, tend...

Jan 1, 1912

The Tennant Creek goldfield is situated in the Northern Territory, 360 miles north of Alice Springs, or a tot~l distance of 1,300 miles north of Adelaide, and 600 miles south of Darwin. The auriferous area extends 20 miles north and south by 50 miles east and west. The overland telegraph line and the AIice Springs-Darwin road pass through the centre of the field.HISTORY, PRODUCTIONThe country comprising the goldfield was traversed by J. MacDouall Stuart between 1859 and 1861 in the course of his last three exploring expeditions, which terminated respectively at Attack Creek, Newcastle Waters and at the mouth of the Adelaide River. The explorer named Tennant Creek and also Mount Samuel, on which mining operations are now in progress. The overland telegraph line was completed in 1872 and a relaying station established eight miles north of the site of the present township. There was no other settlement in the adjacent country prior to the opening up of the goldfield.Gold was discovered in 1926 on what is known as the Great Northern lease, three miles north of the township. The field was remote; the nearest plant at which gold ore could be treated was at Peterborough, in South Australia, 1,186 miles distant, and it was not until 1932 that the development of the field actively commenced.The production of the field from its inception to December 31, 1939, was 57,895 QZ. of gold, valued at £522,000, recovered from 61,793 long tons of ore, won from 98 mines. In 1940 seven of these mines had reached depths between 100 ft. and 230 ft., the workings of the majority being less than 60 ft. below surface.TOPOGRAPHY, WATERThe country is traversed by parallel and sub-parallel lines of hills trending east and west and rising to altitudes varying from 50 ft. to 100 ft. above the intervening valleys. The low ranges and isolated hills owe their survival to the resistance offered by their indurated, harder rocks to erosion which has removed the softer intervening formations. Their elevation and area depend to a considerable extent upon the presence of; and, the size of, the more or less exposed haematite formations, or are due to the influence of extensive siliceous dykes which traverse the locality.Watercourses head from the hills and either flood out on the flats within a short distance, or in a few cases follow longer courses to the northward. In the channels of the larger creeks billaoongs, which form important water storages for a considerable part of the year, -are to be found. Tennant...

Jan 1, 1942

Early in 1940 the development and sampling programmes in hand on the North and British Sections of North Broken Hill Limited were such as to necessitate the drilling of a large number of drill holes ranging up to about thirty feet in length. On the British Section, one purpose was to test the existence, width, and value of narrow lodes believed, for geological reasons, to occur in the walls of the existing workings. Another object was to definitely disprove the existence of payable shoots of ore in certain largerhodonite and quartz-garnet ("garnet sandstone") pillars which had been formerly left as unpayable.On the North Section, the main purpose of the short holes was to delineate the ore-body boundaries by drilling laterally from drives in ore, and thus enable level layout to be planned in advance of sill stoping. It was also desired to test the walls of stopes in those portions of the mine where the economic limit of mining is not rendered obvious by a clear-cut wall, but should be determined by assay. In these latter cases it was hoped to eliminate "prospecting by stoping," a procedure by which any doubts as to the existence of further good ore behind the low-grade walls were settled by continuing to stope laterally until all chance of such an occurrence was removed.LONG HOLE ROCK DRILLINGFollowing an investigation of recorded instances of similar practice elsewhere it was decided to use the rock drill for a series of trial sample holes. A 3-in. drifter was used. This was selected from those in use underground, and was given a special overhaul; had a new machine been purchased, a 4-in. type would probably have been obtained as being more suited to the work. The rods were H in. hollow round steel with a type "1" Jackrod thread. Couplings were of chrome steel, and were H in. in diameter, and 2 in. long. Jackbits (type "1" thread) in sizes from 2 in. to 4 in., with 1-in. gauge changes, gave a range of nine bit sizes. They were resharpened by hot milling, and were not milled to a definite gauge size.After sharpening, bits were sent underground without sorting into sizes, the drillers selecting the next bit with callipers. In view of the small scale of operations, it was not considered worth while to adopt special measures, such as the cold grinding of bits, which might have given a better product. Later, however, new bits were used exclusively, the idea being to accumulate enough blunt Jackbits to warrant a thorough treatment of the sharpening...

Jan 1, 1941

By C J. Pitzer

The prevention of fatal risks is a key objective for the global resources industry, especially considering poor performance with regard to fatality rate reduction and the continued occurrence of mine disasters globally. However, the industry has a credible history, over several decades, of the development and deployment management systems to control potential Serious Injury, Fatal and Catastrophic (P-SIFC) risks. While these systems have had a significant impact on the thinking and approaches to the prevention of fatal risks, fatal accident rates have not shown the desired reduction. Recent fatal and serious injury events in Australia have led to the establishment of several enquiries to further identify improvements that could be considered. Globally, fatal accident rates remain stubbornly high or plateaued in many jurisdictions, and several catastrophic events have occurred, such as tailing dams disasters in Brazil and South Africa, and the recent coalmine disaster in Turkey. Apart from the apparent lack of progress, it is evident that the deployment of critical risk systems has introduced more bureaucracy, slower response systems and additional burdens on already overloaded middle and supervisory levels of management. Organisations are rarely able to effectively tap into the risk source of risk knowledge of the frontline worker and supervisor, for various reasons discussed in this paper. To establish a valid and valuable channel of critical risk information flow from the frontline employee, Debmarine Namibia instigated the development and deployment of a system called SafeSENTRY, where the focus is on the ‘dynamic identification of dynamic risks’. This paper outlines the system, the principles of the design, the range of risk metrics that can be derived from the observations of the frontline operators, and demonstrates how a range of posited shortcomings in critical risk management is addressed how features of the High Reliability Organization (HRO) have been developed.

Mar 29, 2023

This article focuses on TurkeyÆs gold potential with respect to exploration, development and operation after 1985. Apart from TurkeyÆs geology, which offers a substantial number of volcanic-associated gold (Ag) and gold-copper (Au-Cu) projects, there are numerous other factors which make the country a favourable place for mining. Turkey has a mining history which goes back to pre-Roman times and an excellent mining code which ensures security for long-term production. In the country, the Government and local villagers are very positive and the country works extremely well logistically with excellent road and telecommunication links. The opportunities for new discoveries in Turkey are very high. Moreover, Turkey has its eyes turned west as it moves towards joining the European Community and it is no surprise that international companies believe it has got its timing as well as its partner relationship right. Newmont, Teck Cominco, BHP Billiton, Rio Tinto, Eldorado Gold, etc all have direct or indirect interests in Turkey, as do an increasing number of midtier and junior exploration companies. Turkish Koza Gold Mining is the first Au producing company of Turkey. The Eldorado Gold owned 245 t Kisladag Au deposit in Western Turkey is currently also producing Au. In the meantime Anatolia Minerals Development is advancing the 131 t resource at the C÷pler Au deposit in North Eastern Turkey. These are significant world-class deposits. Further encouragement for investment in the Au mining sector has been provided by the introduction of a new mining law in 1985. Foreign investments in the country were encouraged and have seen a rapid increase in the last two decades. Gross domestic product (GDP) growth is in excess of five per cent per annum, inflation is down from 70 per cent to single figures, the budget deficit has been cut by 40 per cent to 11 per cent and industrial output and productivity are increasing rapidly. Turkey is politically and economically stable, is a member of the European Customs Union, has a supportive mining legislation, is highly prospective and under-explored and hosts significant recent gold discoveries.

Jan 1, 2007

By B Mobilio, G B. Sharrock, J L. Lett, I Brunton, T Thornhill

Full-scale marker experiments at Cadia Valley underground operations have been ongoing for over 14 years. Initial marker experiments were undertaken in the Ridgeway sublevel cave (RW) (2002), and subsequently at Ridgeway Deeps (RWD) (2008) and Cadia East PC1 (CEPC1) (2012) block caves. Over 25 000 markers have been installed at the three caving operations to date (approximately 20 000, 3000 and 2500 for RW, RWD and CEPC1 respectively). These experiments aimed to quantify and assess the geometry of the extraction zone, development of the extraction zone over time, variability of flow behaviour and factors affecting flow behaviour in both the near and far field cave column. This paper discusses marker recovery results from the RWD and CEPC1 caves.With respect to the two cave operations, marker recovery in both the near field (markers recovered vertically within 70 m of the extraction level) and far field (markers recovered vertically above 70 m of the extraction level) indicates disturbed flow behaviour where marker recovery is not spatially uniform during material extraction. Two distinct patterns or transient behaviours in the extraction zone are indicated. For RWD (advanced undercut), early material recovery was close to the major apex, and expanded towards the centre of the drawbell as more material was extracted. The inverse was observed for CEPC1 (post undercut), where recovery occurred in the centre of the drawbell initially, and expanded outwards towards the major apex. This trend of recovery for the two operations continued in the far field. In the region above the major apex, recovery was observed for all heights, with no clear height of interaction zone (HIZ) indicated. All of these behaviours significantly deviate from both conventional ellipsoidal flow theory and Laubscher’s (2000) design guidelines. For this reason these new mechanisms are termed the Disturbed Extraction Zone (DEZ).For the CEPC1 marker experiment, electronic markers were utilised to investigate the vector movement of material in the near field. Marker recovery movement vectors in the near field indicate extraction zone widths in the order 30 m, with localised marker recovery outside this region (significant horizontal movement of material potentially due to cave muck pile rilling and blast burden movement). Analysis is ongoing for far field marker vector movement, and will be reported once additional marker recovery has been obtained.CITATION:Brunton, I, Lett, J L, Sharrock, G B, Thornhill, T and Mobilio, B, 2016. Full-scale flow marker experiments at the Ridgeway Deeps and Cadia East cave operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 141–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By C A. Locke, J Cassidy, J L. Mauk

The Waihi-Waitekauri region hosts numerous low-sulfidation epithermal deposits that both outcrop and occur at depth. Zones of intense hydrothermal alteration enclose the Au-Ag bearing quartz vein deposits. Hydrothermal alteration includes the destruction of magnetite by hydrothermal fluids, pervasive silicification adjacent to quartz lodes and potassium enrichment due to adularia and illite deposition. High-resolution airborne magnetic and radiometric, and new gravity data delineate distinct geophysical anomalies associated with hydrothermal alteration and mineralisation. Five magnetically quiet zones occur in the region varying in size from 3 to 34 km2 and in geometry from circular to irregular zones. These zones represent the near-surface extent of strong to intense hydrothermal alteration associated with fossil geothermal systems. All epithermal deposits in the region occur in magnetically quiet zones. Over 120 new gravity stations together with existing data across the Waihi district have defined a positive Bouguer gravity anomaly coincident with the magnetically quiet zone. Eastern and western gradients of 50 gu/km bound the anomaly that contains two flat gravity highs west and east of the Waihi deposit. Strong potassium signatures in airborne radiometric data correlate with outcropping zones of alteration and are consistent with the presence of adularia and illite minerals. Hydrothermally altered zones are represented by areas of low Th/K ratios as a result of low thorium concentrations in andesite and elevated potassium levels in altered zones.

Jan 1, 2003

The Nena high sulphidation-type copper-gold deposit is composed of andesitic pyroclastic units with minor interstratified lava flows. Epiclastic sandstone and conglomerate, and siliciclastic rocks consisting of mudstone, shale, lithic and bioclastic sandstone and conglomerate are locally present. Pre-mineral diorite intruded and domed the volcano-siliciclastic sequence. Economic copper-gold is hosted by vuggy quartz altered lapilli tuff and tuff breccia. The early hydrothermal alteration stage involved deposition of epithermal banded quartz and chalcedonic silica in localised environments. This alteration stage was locally superimposed by a hydrothermal breccia event. Following the breccia event, magmatically-derived volatiles were channelled through a NW striking dilational fault zone and generated the high sulphidation alteration. The high sulphidation alteration is zoned from a vuggy quartz core with local massive replacement silica through a broad pyritic quartz-alunite halo and finally to a thin illite-smectite zone. This is surrounded by regional chlorite-epidote-smectite alteration. A gangue mineral phase consisting of quartz, alunite and baryte overprinted the zoned high sulphidation alteration and preceded the main copper-gold-arsenic mineralisation. Early sulphide deposition is characterised by marcasite, arsenical pyrite and melnicovenite. Main-stage copper-gold mineralisation involved sequential deposition of hypogene bladed covellite+chalcocite, enargite-luzonite and luzonite+stibioluzonite respectively. The copper sulphides are zoned from bladed covellite-chalcocite in the north (cross-sections 5000 - 5600 N) through enargite-luzonite (cross-sections 4700 - 5000 N) and to luzonite????stibioluzonite in the south (cross-sections 4400 - 4700 N). A late phase of minor acicular covellite and enargite+luzonite overprinted the zoned copper sulphides and associated gold mineralisation. Gold mineralisation commenced at the transition from enargite to luzonite, and continued through the deposition of luzonite-stibioluzonite in both stages. Most gold was deposited during the main-stage mineralisation. Yellow native sulphur was deposited in the remaining vugs and defines the waning stage of the hydrothermal system. Post-mineral dioritic intrusives and feldspar porphyries intruded the volcano-siliciclastic sequence. Finally, supergene chemical processes with associated erosion and uplift generated a 40 - 50 m thick oxide-hosted gold cap. The oxide gold cap is underlain by a 35 - 45 m thick blanket of supergene chalcocite+covellite mineralisation which overlies and occurs throughout the main hypogene copper-gold zone. Supergene gold is related to the distribution of primary gold-bearing sulphides. Therefore, remobilisation and redeposition of gold are considered to be insignificant and very localised.

Jan 1, 1999

IN the irregularly shaped ore-bodies of the North Mount Lyell mine by overhead stoping, the method of filling the is a special feature.The situation of the mine two miles from the smelter and mill at an devation of 1000 ft. above the latter, precluded the economical use of granulated furnace or the mill tailings, even if these materials were as suitable for the purpose as the rock nowquarried at North Lyell methods at Mount Lyell have already been described in Proceedings of the Institute.*The breaking the ore in large dome-shaped stopes is still the rule, but the slope or "rill" is much flatter now than formerly. Owing the greater fluidity of the filling now in use, it is sometimes necessary to resort to square-sets, both at the ground floor and above, the roofs and walls are generally enough to permit stoping without timber, except for ground and occasional stacks on the rills.Sufficient area of ground floor has been beaten out to start overhead stoping, the dome back is partly formed, with its apex a rise which connects with the mullock-pass reticulation.(Sce 1 showing this reticulation in diagrammatic form.)

Jan 1, 1927

By G J. Lyman

The theory of sampling has progressed slowly over the last century. The concepts of correct sampling were known to mining engineers such as D W Brunton in the 19th century. It was recognised early in the 20th century that the Poisson distribution of particles carrying the target analyte was the key to the uncertainties between samples of a given mass. However, no efforts were made until the 1980s to determine the entire sampling distribution as a function of sample mass. The variance of sampling was made clear by Gy and others, but none attempted to determine the entire sample assay density function until J H Venter in South Africa applied the method of characteristic functions to the problem.Venter applied the method to a specific case of very low analyte concentrations in samples of very fine particle size where his assumption of constant sample mass was justified. When his general methodology is applied to the more general problem, it can be shown that the assumption of constant sample mass is no longer justified and leads to some anomalous results for sampling variance. Venter’s method can be expanded to allow for a statistically variable sample mass and to take into account the size distribution of particles that carry no analyte.This paper presents the basis of Venter’s work and shows how the approach can be easily modified to yield results for the variance that are consistent, for example, with the work of Gy. It is also demonstrated that the entire sampling distribution can be determined without undue computational burden when sufficient information on the material heterogeneity has been collected.CITATION:Lyman, G J, 2014. Determination of the complete sampling distribution for a particulate material, in Proceedings Sampling 2014 , pp 17–24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 29, 2014

Sluiceboxes can provide a much higher concentration ratio than most other gravity concentrators (up to 50 000:1) at very high overall placer gold recoveries (greater than 99 per cent). They are also very reliable, inexpensive and simple to operate. This combination is very difficult to beat and explains why the sluicebox is still the most important placer gold concentrator in northwestern Canada, Alaska and the rest of the world. A sluicebox is a rectangular fl ume containing riffles on matting, through which a dilute (<12 per cent) slurry of water and alluvial gravel flows. Sluiceboxes are actually centrifugal concentrators with settling velocity playing a minor role in gold recovery. Due to their higher density, gold particles tend to segregate to the bottom of the slurry flow where they form a streamline that is diverted by a low pressure zone into a riffle. Under ideal conditions, this ribbon of slurry will be overturned as it flows down the rear of the following riffle and will continue fl owing in a circular path to form a vortex. At the bottom of this vortex, centrifugal and gravitational forces combine to drive gold particles into or beside the matting. To remove the gold concentrates, sluiceboxes are shut down and the riffles and matting are taken apart and cleaned. The slurry velocity provides the energy that powers the vortex. If the velocity of the slurry is reduced through overloading with solids, insufficient water flows or shallow gradients it may not sustain a full size vortex. If the riffles are too close, too far apart, too tall, or if there is not enough energy available to the vortex, the vortex will not be formed properly and gold recovery will be reduced. If the slurry velocity is too high, extreme turbulence and the resulting scouring will also cause gold losses. Testing sluiceboxes with conventional sampling and evaluation techniques is very costly, time consuming and problematic. Most placer gold ores contain a very small number of gold particles in a large volume of pay gravels. Sluiceboxes can lose coarse gold particles. The presence or absence of one of these particles in a tailings sample can lead to high unpredictable errors (nugget effect) even when large sample volumes are processed with care. Every time conventional samples are upgraded, additional errors are introduced due to the inefficiency of recovery equipment. Nuclear tracer tests are more accurate, faster, cheaper and safer than conventional sampling. In 1989 through 2002, the recovery efficiency of dozens of sluicing systems was determined by mixing radioactive gold particles (tracers) into the feed streams of dozens of placer mines in the Yukon Territory, British Columbia, Alaska and Guyana. Four distinct sizes of nuclear tracers were used and their recovery was related to the design and operational characteristics of the individual sluiceboxes and their pay gravels. At clean up, scintillometers were used to detect the very low level X-ray and gamma ray radiation emitted by these tracers and locate them in the sluice runs. The effectiveness of any given section of riffles was easily diagnosed by the presence or absence of tracers. At every mine the gravel feed rates, water flows, equipment dimensions and riffle performance were measured. After the gold tracers were removed from the fi nal concentrate and counted, the concentrate was sieved and weighed. These gold recovery, weight and sieve data were used to calculate the quantities and size distributions of the gold particles in the original pay gravels and those lost in the tailings. The expired tracers were stored in a lead lined container until their radioactivity was near background levels (about two months). The standard errors from these radiotracer tests were estimated from binomial probability theory with the equation: SE = {(n + p + q) ^ 0.5}/n. Where n was the total number of radiotracers added, p is the proportion recovered and q was the proportion lost. Each overall recovery estimate would be within one standard error of the true recovery value (14 times out of 20) and almost always within two standard errors of the true recovery (19 times out of 20). The maximum standard error with 100 tracers was five per cent and occurred when the recovery approached 50 per cent. With higher recoveries, standard errors usually ranged from one to two per cent.

Aug 1, 2010

By Taylor R. G

This paper reports a biogeochemical study of the Siberia lode of the Herberton tin field. Soil near the orebody contained high levels of Fe, Cu, Pb, Sn, As, Mld Mn. Polycarpaea spirostylis and Indigofera dominii were associated with these high levels but several other species apparently could not tolerate them. The potential of these species as indicator plants is discussed.

Jan 1, 1975

By D Barclay, S Mercer, S Wright

Mine water management is often an afterthought in mine planning processes and can introduce significant risks to projects when studied as a stand alone component at a later stage in the mine design. Incorporation of a mine dewatering and pore pressure dissipation strategy in the early stages of mine planning is imperative in order to minimise constraints on the production schedule, to match designed pit slopes and maximise project value for an open cut mine option such as Olympic Dam. A risk-based mine planning approach was adopted during the project selection phase study whereby water management was introduced into mine planning, scheduling and the development of an operational strategy. Hydrological and hydrogeological studies and outputs were successfully integrated into the various iterations of the mine planning cycle during early selection phase to manage the potential water management risks associated with pit slope depressurisation and access to dry working conditions during rapid advancement of mining phases.An extensive network of vibrating wire piezometer sets and long-term depressurisation testing characterised aquifer conditions and demonstrated that hydraulic connectivity exists within the geological profile due to the presence of structures and resource drill holes which enhance vertical connectivity. This connectivity, along with underdrainage from mining activities contributes up to 100 m of depressurisation in low permeability units.A pit dewatering strategy incorporates the mine planning schedules and accounts for operational constraints as to the location and development of the dewatering wells, storages and pipelines. Numerical modelling generated a range of likely pit inflows and dewatering requirements with the average initial dewatering discharge likely to be 150 L/s and reduce quickly to 50 L/s after five years, depending on the premine schedule.Coupled hydrogeological and geotechnical assessments were also carried out as part of the mine planning cycle and indicate that successful dewatering will go a long way to reduce the pore pressures within key geotechnical units during the rapid mining phase where around 300 m of cover sequence is stripped in five years. However, the residual storage in the primary aquifer and the residual pore pressure in underlying low permeability units will need to be dissipated (in-pit horizontal holes) as the pit floor advances. Pit slope design angles are sensitive to depressurisation and dewatering and up to 70 per cent depressurisation of key geotechnical rock units are required. Whilst an accelerated program of aquifer dewatering supported by lithostatic unloading should drive rapid depressurisation in the lower permeability units, intervention is anticipated in key geotechnical units such as the Tregolana Shale and volcaniclastics. The extent of induced drainage will ultimately depend in part upon the mining rate and geotechnical stability requirements. Practical operability testing addressed the potential for operational constraints to mine depressurisation activities such as congestion and mining schedule development within the pit and identified that depressurisation drilling can be achieved even with reduced access availability. Mine operations and planning groups established design criteria and considered the likely inoperable periods following rainfall events of seven to 14 days to manage the base surge and minimise impact on production. In-pit surface water management options to minimise operational disruptions during and after significant rainfall events were estimated used a stochastic approach.

Jan 1, 2009

The granulites and related "dry" igneous rocks tend to be passed over during exploration for metals. Preliminary data show that high trace concentrations of eu, Ni, and other metals of economic interest are commonin orthopyroxene and some of the other granulite minerals. During retrograde metamorphism of granulites, pyroxenes are converted to amphiboles or phyllosilicates, and significant quantities of metals are released andbecome available for incorporation into new mineral phases, or may be transported elsewhere. S-rich scapolite is the normal scapolite of granulites. Its retrogression to secondary plagioclase provides much S which scavengesCu and Ni, from pyroxenes undergoing retrogression, thus producing ore-fluids. A full analysis of a scapolite with 5·10 per cent SOg is given.Beryl is unstable in granulites but the rare Be mineral taaffeite (Al4Mg(Be, FeII)Os) with 5·50 per cent BeO occurs in central Australia as a pale green tabular mineral easily confused for chloritoid in hand-specimen.Metamorphic differentiation and mobilization of primary ore concentrations are major factors controlling their post-granulite attitude and grade.Zones of retrograde metamorphism are commonly found cutting or engirdling granulite terranes. As the "volatiles" for the new hydrous minerals of many of these zones are of deep-seated origin and may be juvenile, sulphide mineralization in them may also be of mantle origin. However, it is likely that much of the metal content could be scavenged from the granulites as they are down-graded by juvenile volatiles. Major Bouguer gravity anomalies delineate some granulite terranes (e.g. Fraser Block, Western Australia), and are related to deep-seated geosutures and mantle disturbances.Many granulite terranes are linear belts and appear to be welded to older cratonic blocks.

Jan 1, 1969

By F Pirajno

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. China’s mineral deposits are the result of metallogenic processes associated with the geodynamic evolution of tectonic plates and eventual amalgamation into their modern configuration. The principal tectonic provinces of China comprise the North China Craton, Yangtze Craton, Cathaysia Craton, Tarim block, Altay-Tianshan-Hinggan orogens (part of the Central Asian Orogenic Bel), Central China orogens, Songpan-Ganze orogen and Alpine-Himalayan fold belts, which are part of the huge Tethysides. These tectonic elements are testimony to a complex geological history spanning more than 3000 million years. This contribution will focus on selected areas of the Altay-Tianshan, the fold belts surrounding the North China Craton and Yangtze Craton and the mineral systems along the Ailaoshan-Red River fault zone. Mineral deposits in these provinces include gold, copper, molybdenum, tin, antimony, nickel, platinum group elements, lead and zinc.CITATION:Pirajno, F, 2015. Metallogeny and related tectonic settings in China , in Proceedings PACRIM 2015 Congress, pp 17–24 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Ghosh I, Vanangamudi M

Experiments have been made in a laboratory heavy media separator at various specific gravities of separation using zinc chloride solution and magnetite suspension as media for different types of coals. The results indicate that the magnetite bath gives at better separation than zinc chloride solution. Even though the probable error remains the same for most conditions of operation, the error area is found to have a wide variation which emphasises the importance of the error area over probable error in evaluating the performance of a cleaning unit.

Jan 1, 1981