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A massive cobalt-containing pyrite orebody occurs in banded albite-quartz-biotite rocks at Thackaringa, some 30 km SW of Broken Hill. Because of the world-wide shortage of cobalt during the late 1970s, serious consideration was given to the development of a suitable flow-sheet to recover the cobalt from this ore. Details of a pressure leaching process in which more than 90 per cent of the cobalt is extracted from a pyrite concentrate are presented.

Jan 1, 1983

FOR many years past it has been the practice at the Bairnsdale School of Mines to treat any parcels of auriferous concentrates sent in from the surrounding district by roasting them in a handworked reverberatory, and then chlorinating or cyaniding the product. According to Donald CIark, who has done a large amount of work on these ores, the results obtained were fairly satisfactory extractions of over 90 per cent being claimed. With some modifications, the method has been very generally adopted, not only in Gippsland but throughout Victoria. It is, however, difficult to get exact information as to the extractions actually obtained, and unfortunately no records of working results have been kept at the Bairnsdale School of Mines.Having treated several lots of ore by this method during 1907 and 1908 with unsatisfactory results, the writers thought it desirable to make a detailed investigation on some particular ore, both in the laboratory and on a working scale. The ore selectedwas a parcel of low-grade concentrates from Stirling, a small mining field situated about forty miles to the east of Bairnsdale. This ore was chosen chiefly on account of the heavy and inexplicable volatilization loss which took place even on roasting with the greatest care; the loss amounting to between 10 and 15 per cent. In the experiments here related, three main objects were kept in view:-1. To determine with what mineral 01' minerals the gold and silver were associated...

Jan 1, 1909

Cyclone Process for Heavy Metals Decontamination of Sediments

Sep 13, 2010

By J Elsen, R Snellings, K Van Balen

This research concerns the mineralogical study of the physico-chemical reactions taking place at the pozzolan-binder interface. Lime binder/ pozzolan mixtures have been prepared for different natural zeolites. Analcime, phillipsite, chabazite, erionite, mordenite and clinoptilolite were mixed with portlandite and water, after which the progress in the reaction was quantitatively determined by thermogravimetrical analyses from three to 180 days. A first and important step was the thorough characterisation of the raw materials by quantitative X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope energy- dispersive X-ray (SEM-EDX) measurements of the zeolite minerals, Brunauer-Emmet-Teller (BET) specific surface area measurements, grain-size analyses and cation exchange capacity measurements. Beside these zeolite samples with varying Si/Al ratios, two clinoptilolite samples exchanged to the calcium, potassium and sodium form were studied and the difference in their short- and long-term reactivity was assessed. Also the difference in reactivity between identical clinoptilolite samples ground to different grain sizes, obviously having different specific surface areas, was determined experimentally. The results indicate that the external surface area only influences the short-term reactivity, whereas the cation content has effect on both long- and short-term. Na-exchanged samples combine clearly more portlandite in the first few days, whereas the reaction slows down afterwards compared to K- and Ca-exchanged samples. The early reactivity of the unexchanged zeolite samples could be explained by these two parameters, but their long-term reactivity seemed to be related to their Si/Al ratio. Samples with zeolites rich in Si reacted faster then their Al-rich counterparts.

Jan 1, 2008

This paper gives an overview of the difficulties associated with determining the strength of hard rock pillars. Although a number of pillar design tools are available, pillar collapses still occur. Recent examples of large scale pillar collapses in South Africa were caused by weak partings which traversed the pillars. Currently two different methods to determine the strength of pillars are used namely, empirical equations derived from the back analyses of failed and stable cases and numerical modelling tools with an appropriate failure criteria. Both techniques have their limitations and additional work is required to obtain a better understanding of pillar strength. Empirical methods are popular and easy to use, but care should be exercise that the results are not extrapolated beyond the range of the data which were used to derive them. An example is the Hedley and Grant formula (derived for the Canadian uranium mines) that has been used for many years in the South African platinum and chrome mines (albeit with some adaptation of the K-value) to design the pillar layouts. Very few collapses have nevertheless been reported and it might even be too conservative an assumption of pillar strength in these mines. As an alternative, some engineers strongly advocate the use of numerical techniques to determine pillar strength. A close examination unfortunately reveals that these techniques also rely on many flawed assumptions. An area where numerical modelling is invaluable, however, is to study specific pillar failure mechanisms, such as the influence of weak partings on pillar strength. In conclusion, it appears that neither empirical techniques nor numerical modelling currently provide a solid basis to conduct pillar design. It is therefore recommended that both these techniques be utilised when confronted with a pillar design to obtain the best possible insight into the problem.

Nov 25, 2010

By Rao P. K, Sahoo P. K

The main constituents of ferromanganese slags are silicates of Mn, Ca and AI. Factors affecting the recovery of manganese from a low manganese content ferromanganese slag (about 16 per cent MnO) during acid leaching were studied. These included time, temperature, agitation, sulphuric acid addition, solid:liquid ratio and particle size. Agitation rates greater than 300 rev/min. leaching periods greater than 30 min and temperatures above ambient were found to have no effect on Mn recovery. Dissolution of Mn was found to be highly dependent on the amount of acid added.About 90 per cent of the Mn was recovered when 5·5 times the stoichiometric amount of acid was used. About 28 per cent of the Mn was recovered when the stoichiometric quantity of acid (with respect to Mn alone) was used. However, the recovery increased to about 75 per cent when the total stoichiometric requirement of acid with respect to Ca, Al, Mg and Fe as well as Mn was used for leaching. The extent of Mn dissolution also depended on the particle size of the slag. The percentage of Mn recovery (using 5·5 times the stoichiometric amount of acid) increased from about 60 per cent to about 92 per cent when particle size decreased from -36 +52 to -150 +200 mesh (B.S.S.). When the results of this study were compared with those in a previous study involv,ing the leaching of a high manganese content slag (containing about 40 per cent MnO) results were similar except that there was a gr-eater consumption of acid in the present case (i.e. low manganese content slag).

Jan 1, 1979

In presenting this paper the author has in view a twofold purpose. In the first place, it is intended to set forth for the benefit of practical mining men some account of the principles underlying the design of tungsten carbide rock bits in the hope that a knowledge of these principles will assist in the successful application of the bits to mine and quarry drilling. Secondly, by evoking discussion, and even controversy, it is hoped that manufacturers and users of these rock bits will be encouraged to contribute to the general knowledge of a subject which to date has been rather lacking in published literature. The author well appreciates that many of the conclusions drawn in this paper are highly controversial, but if the only result is to call forth contradictory testimony from other workers in this field, at least one of his purposes will have been achieved.An attempt will first be made to set forth and examine those characteristics which go to make up an efficient rock bit, and the main factors affecting these characteristics will be discussed. In a paper of this general nature, consideration of any particular aspect must necessarily be rather brief, and there is little opportunity for detailed presentation of test procedures and data. Thus, it has been found advisable' to confine discussion of some minor points to a simple statement of fact. However, an attempt has been made to support all major conclusions by reference...

Jan 1, 1950

The following data cover a phase in the systematic testing of gold deposits which does not appear to have been specificalIy investigated.In boring either secondary or primary deposits, gold, by virtue of its high specific gravity, will tend to migrate downward, below the driving shoe or bit, and thus cause misinterpretation of value unless final recovery Can be effected after the hole has been bottomed.Unlike fortuitous and non-recurrent errors, due to, say, running ground, "pile driving" or rock fractures, systematic error due to migration may be unpredict.able from operating data alone, and, therefore, result in serious miscalculation of the weighted average upon which the engineer's recommendation is based.Applied to diamond drilling, loss by downward migration appears to have been largely responsible for distrust of sludge assays in the past. On the other hand, although modern practice rightly trends towards an integration of both core and sludge samples in borehole valuation, the possibility of systematic loss must be investigated when using combination graphs such as those of Longyear, Moehlman and WeIler. If the sludge value is incorrect the combination graphs will serve solely to stultify the core valuation.It appears to be axiomatic that: 1. With full core, sludge assays are of minor import.2. With recovery above 90%, differentjal grinding, of the high grade sections may have occurred, and this c!ln be corrected only by the us.e of cOJ;rect sludge valuation.3. With core recovery less than, say, 70%, no accurate valuation is possible without integrating the sludge assay.4. With less than, say, 10% core recovery, the sludge assay affords the sole basis of evaluating a borehole which may have cost many hundreds of pounds.The conditions demanded for reliable sludge valuation have, in practice, been restricted to high quantitative recovery and return of nearly 90% of the drill water. It is submitted, however, that the following additional knowledge is required:1. The nature of gold distribution in the ore.2. The lifting power of the return water column, which can be gauged by the maximum quartz particle, provided that the degree of "hindrance" can be determined.3. That all gold has been cleared from the bottom of the borehole immediately after it has passed through the orebody.The three cases discussed hereunder are offered not only as proof of the thesis, but also in the hope of promoting discussion on the interpretation of borehole values and on methods for saving free gold in the sludge. The fact that two of them cover alluvial boringand the third diamond drilling has resulted in this attempt to reduce the behaviour of free gold to a basis common to all types of boring.

Jan 1, 1950

For a large scale open pit mining and concentrating operation, on a low-grade disseminated ore body, it is possible to set an approximate lower bound on economically feasible operating scales and an approximate upper bound on economically desirable scales in a relatively straight forward manner. The optimum scale ofplanned operations, with respect to the objective ofmaximisation ofthe net value ofthe orebody, will have to be arrived at by iterative planning runs, but it may be expected to lie close to this upper bound. The effects of infrastructural costs and of the addition of a risk premium to the cost of capital, to form the discount rate for planning purposes, are considered theoretically and by worked example. It is concluded that a perceived special, unsystematic, risk should not be accounted for by the use of such a risk premium as this is inducive to placing a greater amount of investment capital at risk, for no greater return-rate to investment.

Jan 1, 1986

Close spatial relationships between the deposits of the Etheridge Goldfield (23 000 kg of bullion) and various regional geological and geophysical features suggest that genesis of the ore deposits was a multi-stage process that started with magmatic and metamorphic stages in the mid-Proterozoic, climaxed with structural and hydrothermal stages in the late Palaeozoic and terminated with an oxidation enrichment stage in the Cainozoic.This hypothesis permits classification of the Georgetown region into areas likely to contain deposits of the Etheridge type and those unlikely to do so; it is concluded that there is little scope for the discovery of extensions of this field.However, the stratigraphic interval between the postulated source rocks of the Etheridge field and stratigraphically higher host rocks of the Croydon field may contain disseminated replacement gold deposits of the Carlin type. The potential host (Pyritic carbonaceous, and locally dolomitic siltstone of the Candlow Formation) is locally faulted and cut by granitoids and the extension of a mineralised, long-standing zone of structural weakness.

Jan 1, 1981

By Mwaba CC

Ok Tedi Mining Ltd has been using flotation for the production of copper/gold concentrates from a complex copper sulphide ore for several years. During this period, much effort has been devoted to metall- urgical treatment of the ore. This paper examines some of the mineralogical aspects of the sulphide minerals in the ore using the electron microprobe analyser. Results have revealed the complexity of the copper sulphide minerals and in particular, chalcocite. Analysis of both plant and laboratory flotation products has provided further insight into the effects of mineralogy on the flotation of copper and iron sulphides. A significant observation is that some of the pyrite minerals apparently exhibit natural floatability. The implications of the mineralogical characteristics of the sulphide minerals on the flotation of the ore are also discussed.

Jan 1, 1991

By Garnsey R. G T, Wenk G. J, Toop A, Sowerby B. D

A bulk mineral analyser (BMA) suitable for the determination of Cu or Ni in bulk ore samples has been developed at the Lucas Heights Research Laboratories. This analyser, which uses the nuclear resonance scattering technique, is highly specific to the wanted element. The technique has previously been extensively field tested for copper at Mount Isa, Queensland.The present paper discusses the field trial in 1982 of a commercial prototype BMA for nickel. The trial was undertaken at the lateritic nickel mine at Greenvale, Queensland. The BMA and its shielding, together with a laboratory spectrum analyser, were sited in the sample shed adjacent to the workings. Two hundred and thirty-eight ore samples taken directly from the mine blastholes were assayed by the BMA. The average mass of sample was 12 kg, metal contents varied from 0.2 to 3.5 wt/per cent Ni and 4 to 43 wt/per cent Fe and free moisture varied from 11 to 55 wt/per cent. A measurement took 10 min to complete, although this time could have been reduced at the higher nickel grades. The r.m.s. deviation between BMA and chemical assays was 0.09 wt/per cent nickel. Iron and bulk density were also determined by the BMA, r.m.s. deviations being 1.7 wt/per cent and 0.03 g/cmJ respectively. Similar results could be expected from a BMA in routine industrial use at other nickel mines.

Jan 1, 1983

Gold recovered on the strikes at the Central Norseman mill, Norseman, Western Australia, has an approximate assay fineness of 850. Bullion recovered from the cyanide plant at the mine is of much lower value, and occasionally its assay fineness has been as low as 250. This indicates either that the fine gold particles in the ore consist of an alloy richer in silver than the coarse particles or else that a silver mineral, as well as the gold, is dissolved by the cyanide solutions.It had been observed at the mine that the amount of silver in the bullion appeared to increase when galena appeared to be more abundant in the stoped ore. Interest was, therefore, attached to the possible occurrence of a silver mineral associated with galena and, at the same time, soluble in cyanide.Four specimens of ore from different horizons in the mine were collected by the mine staff for examination as to whether any marked difference in the fineness of gold was apparent on a polished surface and for determination of the silver minerals. As the Norseman ore-body is a quartz reef containing a very small percentage of sulphide, the specimens were selected either because they cont;:lined free gold or because they were, relatively rich in sulphides. They were obtained from the following localities at the Phoenix shaft.1. Level 16, section 28.2. Level 16, section 31.3. Level 8, section 31.4. Level 14, section 38.Specimens Nos. 1 and 2 were thus obtained from different positions at the same mining horizon, while specimens Nos 2 and 3 were obtained from different levels in the same vertical section of the mine.All the specimens consist of quartz characterized by thin, discontinuous seams of sericite and the presence of a little ankerite. Gold and sulphides tend to be localized along these seams, but particles of gold and sulphides are also scattered throughout areas of white quartz. This scattered distribution of the sulphides in relatively wide areas of quartz has involved the preparation of two or more polished sections from each specimen.The outcome of the microscopical examination of these specimens has been to determine that there is no appreciable variation in the colour of the polished particles of gold and, therefore, no marked difference in the amount of silver alloyed with the coarse and fine particles. The presence of small quantities of the tellurides sylvanite, hessite and altaite has been revealed, and found to vary in abundance with the abundance of galena.

Jan 1, 1944

Over half of the molten aluminium produced at the 52,000 tons/ year eapacity plant operated by Comalco Aluminium (Bell Bay) Limited in Tasmania is cast into saleable produets by the direct chill process. Considering the importance of direct chill casting to the aluminium industry it is surprising that so little published literature on the subject is available, although Easton (1947), Smart (1954), and Uppert (1940, 1944, 1945) have contributed much toward lifting the veil of secrecy surrounding the process.The direct chill, or D.C. process as it is commonly called when related to aluminium, consists basically of feeding molten aluminium or its alloys into; water-cooled mould from the bottom of which solid aluminium is continuously extracted. Although the casting procedure is continuous in principle, the equipment is normally operated in an intermittent manner. Castings up to 20 ft long are formed during a cycle. At the end of the cycle casting is stopped and the pit into which thc castings are dropped is cleared before a new cycle commences. Depending on the size of the casting in relation to the cross sectional area of the pit and the support mechanism (commonly a hydraulic ram), 'drops' of up to 15 tons are not uncommon. This method of D.C. casting IS termed vertical D.C. casting and is the one most commonly employed in the aluminium industry.Horizontal casting has come more to the fore in recent years with the casting being extracted from the mould in the horizontal plane and is a truly continuous casting method since flying saws can be simply used to cut the continuously cast shape into required lengths as it emerges from the mould...

Jan 1, 1967

By S Hapugoda, M Kilburn, M Adam, L Lu

Lump ore is one of the key ferrous materials used in the blast furnace ironmaking process, typically accounting for 5–25 per cent of the blast furnace ferrous burden. Like other ferrous materials, the characteristics of lump ore have an important impact on stable operation and productivity of a blast furnace. As the cold burden lands on the top of the hot burden in the furnace and descends, it is inevitably subjected to thermal shock, which will likely lead to breakdown of the lump particles, or decrepitation and affect the gas permeability inside the blast furnace adversely. An ISO decrepitation test has therefore been developed to assess this behaviour of lump ore. However, the results obtained according to the existing standard decrepitation test method vary considerably between laboratories even for the same lump ore. To improve the test procedure of the existing decrepitation test, this paper first discusses the mechanisms leading to decrepitation and then studies the factors affecting lump ore decrepitation. Understanding the key factors affecting lump ore decrepitation is particularly important to improve the existing test procedure that enables researchers to achieve a higher degree of precision when conducting the decrepitation test.CITATION:Lu, L, Adam, M, Hapugoda, S and Kilburn. M, 2017. Decrepitation of lump iron ores, in Proceedings Iron Ore 2017, pp 91–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Six simulations by the Mpnte Carlo method employing both classical and geostatistical techniques are presented for the determination of the probability distribution of the in situ value of a coal seam. To avoid the problem of qualitative estimation of parameter variability in the calculation of an arbitrary seam value, only data values from borehole information were used to quantify the variation in four coai seam parameters.The method which is suggested as being the most appropriate is a particular geostatistical approach that employs the best linear unbiased estimate and the error of estimation for a number of two dimensional blocks. The results indicate that the variance of the coal seam unit value may be much higher than that indicated by the classical approach because of the spatial variability that is properly incorporated in the geostatistical approach.The model used in the Monte Carlo simulation to determine the economic value of a coal seam can be extended to incorporate all those parameters which are necessary for a true estimation of the probability distribution of the coal seam value. A time value concept for discounting can also be incorporated to optimize the economic return of a coal mining project.

Jan 1, 1983

Your Excellency, on behalf of the Council of the Australasian Institute of Mining and Metallurgy, and, indeed, on behalf of everyone present, I extend to you a welcome, and our thanks for your gracious acceptance of the invitation to be here to-day and, later on, to present Honorary Membership Certificates. I also welcome the several official representatives of our Allies, of Great Britain and our sister Dominions.To Messrs. E. C. Driffield and E. J. Rigby, two of the original Foundation Members, who are with us to-day, I extend greetings.The present occasion is opportune to express, on behalf of a representative body of professional men, deep appreciation of the sacrifice which His Majesty the King has made, and will continue to make, by appointing His Royal Highness the Duke of Gloucester as Governor General of Australia and, therefore, His Majesty's senior personal representative in this country.I suppose, that as the primary reason for our assembly to-day is to celebrate the Fiftieth Year of the Institute's existence, I should properly on this occasion, give an account of its history and development. However, as this subject was ably covered by Mr. L. V. Waterhouse, in his Presidential Address in 1938, I trust I may be excused for selecting some other subject. I shall, therefore, exercise my privilege as President and give you a short history of the Mining and Metallurgical Industry of this country with special reference to its effect on the development of the Commonwealth and on the national economy. I apologize in advance for any statistics which I inflict upon you; some of these will be three or four years out of date, because of censorship restrictions. I shall as far as possible refer firstly to the industry prior to and including 1893, the Institute's foundation year, and then to subsequent development.Australia, is pre-eminently a pastoral and agricultural country and it leads the world in the production of wool. Nevertheless, it has an international reputation as a producer of gold and various metals and of minetal products.The development of gold mining in the decade 1840-50 was an epoch-making event in Australia's history, because, to quote one writer's apt phrase, "it precipitated Australia into nationhood." It was certainly responsible for a rapid increase in population. Thus, during the period 1841-1861 the population of Australia increased fourfold, from 221,000 to 1,170,000.The effect of the discovery of gold in Western Australia was even more striking. In 1890 the population of that State was 49,000 and in 1900 it was 180,000.Statistics in respect of gold are reasonably complete, even for the years prior to Federation, and it is interesting to note that the gold declared as...

Jan 1, 1944

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

Characteristics Analysis of a Bastnaesite Rare Earth Mineral for Recovery of Cerium

Sep 13, 2010

Mineral deposits in New Zealand whose origin can be ascribed to primary magmatic segregations are associated with mafic-ultramafic complexes related to two orogenic episodes which took place during Palaeozoic and Mesozoic times. These mafic-ultramafic complexes are essentially of two types. One is ophiolitic and has podiform chromite mineralisation presumably formed below a spreading ridge. The other type occurs as intraplate layered intrusions in which Fe-Cu-Ni sulphides and Fe-Ti-V oxides have formed as a result of liquid immiscibility with the host magma, and have subsequently accumulated by gravity means. Generalised descriptions are given for some deposits in NW Nelson, Fiordland and Marlborough districts.

Jan 1, 1980