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Fine coal is defined as material with a maximum size of 1/2 in. Various methods for separate washing of such coal are discussed briefly because separate treatment can lead to a higher overall recovery of coal or to a product having a lower ash content.A felspar jig is discussed in detail because it is the method most recently adopted in Australia, and because it has the advantages of compactness, flexibility and automatic Gontrol, with minimum operator attention. This jig has a variety of adjustable controls to enable the desired results to be obtained from a wide range of coals and the general application of each control is discussed.The only separate treatment of fine coal in the Illawarra district is by felspar jigs on Bulli seam coal.INTRODUCTIONAll reasonably large Australian collieries now win coal by mechanical methods. but while mechanization leads to more economic production of high tonnages, it also changes the characteristics of the coal won. In particular there is an increased proportion of fines, and an increased ash and moisture content. However, specifications of coal for sale have become more stringent, and consumers now require coals in a definite size range with a lower and more uniform ash content, as well as with a low and uniform moisturecontent.These factors have led to the need to wash and grade run-of-mine coal at the pithead. In' plants where the whole of the run-of-mine coal is treated in a jig, some of the fine coal in the feed is beneficiated; the extent depending on factors such as the type of coal and the feed rate. However, for dense medium treatment, fine coal must first be screened out, and there may then be no washing of fine coal at all.

Jan 1, 1961

By Creelman C. A

With the technique and data obtained in using the blast hole diamond drill for "Removal of Horizontal Level Pillar by means of Blast Hole diamond drilling at New Occidental Gold Mines N.L.," as described in Proceedings No. 133 of 1944, and a series of experiments using the blast hole diamond drill for stoping at New Occidental and New Cobar Mines over the past two years, a benching method of stoping has been developed using 2 inch coring diamond drill bits, resulting in efficient and economical ore extraction in these large ore bodies.During the experimental stages the standard H-inch blast hole was used, but the deflection of the holes, when using this solid bit, either decreased or increased the burden of the hole when it became necessary to drill holes deeper than 45 feet.It was found that after blasting vertical holes deeper than 45 feet, the ore did not break satisfactorily over the full length of the hole; on one occasion as much as 30 feet of bench was left at the bottom of the face, which had to be subsequently re-bored andblasted.As this defect was also noticeable to some extent even when the holes did not deflect, it was then obvious that the explosive had become less sensitive in the lower section of the hole. This was probably brought about by pressure being built up ahead of the detonation wave in H-inch hole, resulting in desensitization of the explosive.Another series of experiments were carried out, using 2-inch solid bits, which enabled a much greater burden on the holes, and the use of primacord for the full length of the hole.This gave satisfactory results regarding breaking and fragmentation, but was uneconomic owing to the excessive consumption of diamonds, and the slow rate of drilling.Further experiments were then carried out using 2-inch coring bits, (Fig. 1) which allowed holes of 90-feet to be bored with little deflection, and proved to be entirely satisfactory as to cost and speed of drilling.

Jan 1, 1945

The ultraviolet spectrum of isopropyl ethylthionocarbamate (the principal constituent of Dow flotation collector Z-200) in water and of Z-200 itself in water was found to have an absorption peak at 242 nanometers(nm). The height of this peak was found to be directly proportional to isopropyl ethylthionocarbamate concentrations up to 15 p.p.m. Z-200 contains about 90 per cent isopropyl ethylthionocarbamate and the heightof the peak was proportionately lower, but obeyed the straight line relationship up to 15 p.p.m. This showed the potential value of spectrophotometric measurements for the determination of Z-200 residuals in flotation liquors.Methyl ethyldithiocarbamate (an impurity in Z-200) increased the peak height slightly, but other impurities in Z-200, xanthates, and most inorganic salts present in flotation liquors do not interfere. However nitrate ion and thiosulphate ion have absorption peaks which overlap the isopropyl ethylthionocarbamate peak.The simplest general method to overcome this effect is to extract the isopropyl ethylthionocarbamate into cyclohexane and to measure the absorbance of the extract.The maximum absorbance of the cydohexane extract was at 247 nm and the peak height at this wavelength was found to be directly proportional to the isopropyl ethylthionocarbamate or Z-200 concentration in the original aqueous solution. An alternative method is to measure the spectrum of the original aqueous solution using the aqueous raffinate from extraction as a reference solution. This gives the spectrum due to isopropyl ethylthionocarbamate alone and measurement of the absorbance at 242 nm gives the concentration in the original aqueous solution. Both methods give the same value for the concentration of isopropyl ethylthionocarbamate in the original solution.

Jan 1, 1969

By Arndt C. R

The Ispat Mexicana SA de CV (IMEXSA) pelletising plant is located at Lazaro Cardenas on the west coast of Mexico. It is the primary source of feed stock for the adjacent direct reduction (DR) plants and steelmaking facilities. The initial design of the pellet plant began in 1981 for 3 Mtpa of DR grade pellets using local concentrate received by pipeline.' Several construction delays, an ownership change, and a decision to use imported concentrates delivered in 60 000 to 90 000 tonnes ship cargoes required flowsheet modifications and additions. The design concepts are described for the plant which includes concentrate regrind to final pelletising particle size.

Jan 1, 1999

By F Gervilla, J Laukkanen

The Kevitsa Ni-Cu-PGE deposit in northern Finland contains disseminated Ni-Cu-Fe sulfides, and platinum-group minerals (PGM). The 2.05 Ga-old ultramafic-mafic, funnel-shaped intrusion is intruded into a volcanosedimentary sequence. The major ore minerals are pentlandite, hexagonal pyrrhotite and troilite, chalcopyrite, cubanite and magnetite. Pyrrhotite and pentlandite are replaced by pyrite, millerite and heazelwoodite near the surface. Nickeline, maucherite and gersdorffite are locally abundant. A pilot feed sample of 575 t of the main orebody at Kevitsa had average grades 0.45 per cent Cu, 0.36 per cent Ni, 1.85 per cent S, 0.33 g/t Pt, 0.34 g/t Pd and 0.19 g/t Au, with 0.06 per cent Ni contained in silicates. Higher PGE contents (2 - 27 ppm) occur in a vertical N-S bearing fault zone. The PGM (n = 6022) mapped in specimens of four drill holes, consist of sperrylite 34.7 vol per cent, braggite and cooperite 18.5 vol per cent, geversite 17.2 vol per cent, moncheite 14.7 vol per cent, merenskyite 6.7 vol per cent, stibiopalladinite 4.3 vol per cent, sobolevskite 1.9 vol per cent, kotulskite 0.7 vol per cent, michenerite 0.6 vol per cent, keithconnite 0.3 vol per cent, rustenburgite 0.1 vol per cent, melonite, froodite, laurite together 0.1 vol per cent and only a few grains of sudburyite, irarsite, vysotskite, erlichmanite, hongishiite, Pt-Cu-alloys, three undefined Pd and Pt bismuthinides and antimonides and a Pd-Cu-bearing Pt-Ni-Fe sulfide. Most of the PGM, 62 per cent, are enclosed in silicates, 29 per cent are intergrown with sulfides, nine per cent are within sulfides. A portion of the PGE occurs in solid solution in sulfides and arsenides. Ni flotation yielded smelter-grade concentrates averaging 12.2 per cent nickel. The average sulfide Ni recovery is 78.8 per cent and total Ni recovery is 65.3 per cent. The average Pt is 10 g/t at 55 per cent recovery, Pd 7.7 g/t at 38 per cent recovery and Au 1.6 g/t at ten per cent recovery. Cu concentrates averaged 28.6 per cent Cu with an average recovery of 78 per cent and further 11 per cent in the nickel concentrate. The copper concentrate contains 4 g/t Au at 24 per cent recovery. The average Fe to MgO ratio 17.9 is well above the targeted minimum of 4.5. The pilot results show that the previously used TETA (triethylene tetramine) can be avoided and good quality, smelter-grade concentrates can be produced from the Kevitsa ore at economical levels of recovery by conventional flotation methods.

Jan 1, 2008

By Wilson A. F

The use of stable isotopic measurements as a technique for elucidating the origin and history of the water in hydrothermal fluids is relatively new. Recept studies have emphasized the importance of meteoric water in the formation of many hydrothermal ore deposits including many epithermal gold-base metal deposits which occur in faulted volcanic terrane. Other vein-type gold ores are believed to have formed from fluids of magmatic or metamorphic origin and exhibit characteristic d18O values. Preliminary oxygen and carbon isotopic data for some important gold deposits of eastern Australia have emphasized the diverse origins of their ore fluids.The Mount Morgan gold-copper orebody is shown to be of the volcanogenic massive sulphide type with ore fluids predominantly of sea water origin. The Charters Towers fissure veins formed during hydrothermal activity associated with intrusion of Lolworth Igneous Complex equivalents. Oxygen isotopic studies of the quartz reefs at Stawell and Gympie have been inconclusive. The ore fluids have a d18O value of about 7 per mil and may be of magmatic or metamorphic derivation.

Jan 1, 1981

During the drilling campaign conducted between October, 1942; and May, 1943, to prove the extent of the scheelite deposit worked by King Island Scheelite N.L. at Grassy, King Island, Tasmania, 35 holes were drilled and 606 samples recovered and assayed for their content. Of these, 238 came from outside the limits of the orebody and were for the most part barren, although a few contained some scheelite. The present statistical analysis is made only of the 368 samples taken from diamond-drill cores of the orebody itself.Drilling Pattern and Sampling MethodsFrom the purely statistical viewpoint, it is realised that methods employed in selecting sites for diamong.-drilling, and of collecting samples from drill cores, do not give a completely unbiassed set of data for analysis. Fig. 1 is a sketch plan showing the relativepositions of the drillholes, which were inclined at an angle of depression of 50 deg. The pattern does not conform to a properly randomized and' regularly-spaced grid, the positions of the later holes being determined by the results obtained from previous holes.Statistically, the bias is, therefore, favourable. The unequal spacing of the drill holes and the lack of uniformity in direction of the lines along which the holes were drilled are unsatisfactory from the mathematical viewpoint; but it is realised that these irregularitiesare difficult to avoid in determining by the most economical methods the extent of such an orebody, and are dictated by geological rather than mathematical necessity.Sampling, also, is lacking in complete uniformity. Each sample is approximately 10ft. in length. However, owing to the fact that 100% recovery of core is rarely achieved, and actual lengths of samples taken are ,primarily governed by the length of the drill runs,and secondarily by lithological changes, there is a considerable amount of variation in the sample length.AssayingWith the exception of 28 samples from three drill holes all samples dealt with in this paper were assayed in the Melbourne University Ore-Dressing Laboratory of the Commonwealth Scientific and Industrial Research Organisation. These assays were given to the nearest 0.05% WOg as it was considered that more accurate determination was not possible. This fact has been taken into consideration in the frequency analysis below. The 28 assays determined by the Tasmanian Mines Department were given to the nearest 0.01%.

Jan 1, 1950

By G J. Corbett, T M. Leach

Approximately 42 t of mercury were produced from Puhipuhi from the late nineteenth century until the end of World War II, with no significant gold or silver production. Sinter, eruption breccias and veins, mined for mercury at Puhipuhi and essentially barren of gold, are inferred in many geological models to represent the surficial levels of adularia-sericite style low sulfidation gold-silver systems. These systems may contain economic gold-silver mineralisation at depth. Conceptual geological models have been employed at Puhipuhi in the search for buried gold mineralisation. Homestake Mining utilised a McLaughlin model for exploration from 1982 to 1987, targeting mainly the vicinity of the sinter deposits. From 1987 to 1989 BHP sought deeper structurally controlled gold mineralisation within the basement greywackes, utilising models derived from studies of Round Mountain, USA and Hishikari, Japan. Macraes Mining Company Limited have accessed the previous work and applied a conceptual geological which invokes a north-south structural control for the emplacement of high-level felsic intrusions at depth. Dextral movement on these structures associated with oblique convergence facilitated the formation of a pull-apart basin in which lacustrine sediments overlie basement greywackes and are in tum overlain by Pliocene basalts. Continued activation of the NS structures created a series of inferred NE-trending dilational structures, which are targeted as fluid upflow centres for the surficial outflows. Upflows occur as eruption breccias (e.g., Plumduff) and outflow as silica sinters (eg Mt Mitchell, Williams) which are also partly obscured by the basalt cover. Argillic alteration and mercury mineralisation occur at elevated crustal levels (eg Puhipuhi mine). Modelling from structure and alteration zonations have targeted a fluid upflow in the vicinity of Bush Hill, which was not accessed by previous workers. This target was subsequently supported by surface geology and multi-element soil geochemistry.

Jan 1, 1997

Previous methods for measuring the flow of solids in Jnrdraulic conveying have not considered the important effects of slip velocity and particle concentration. In this paper an extension of the method proposed byShirato et al. (J. Chem. Engng. 'Japan, 1: 164-167) for determining mass flow in a vertical conduit is outlined.The present method consists of measuring' the volumetric flow of the slurry (by a magnetic flow meter for instance) and the density of the slurry in two pipe sections of different diameters. Effects of variation of slip withparticle concentration, not previously considered, are allowed.Problems involved in estimating the density of a slurry from differential pressure measurement are discussed.The major problem is the uncertainties in estimating frictional losses due to the wall in two-phase flows. The greater reliability of a more "direct" technique, such as by 'Y-ray absorption, for measuring solid concentration is emphasized.

Jan 1, 1971

With the exhaustion of orebodies close to the main haulage shaft of the Emperor mine, an increased rate of development, aimed at earlier investigation of values disclosed by exploration drill holes has been attained with an overall reduction in unit costs.This paper describes the techniques used in rates of advance up to and exceeding 1,000 ft per 28-day period.

Jan 1, 1966

In the course of the last twenty eight years the copper lodes of New Caledonia have been periodically worked or abandoned, until quite recently, probably attracted by the higher price of the metal, British capital has again been induced to embark upon the further development of several copper properties, which at present give reasonable promise of becoming regular producers. Owing to its proximity to Australia (only a three day's journey by mail steamer from Sydney) New Caledonia becomes of additional interest to Australian commerce in general, and it is to be hoped that the French Government may see their way before long to make the best of this natural position, to the mutual benefit of both countries concerned.Op till now all copper ores and concentrates which have been shipped from New Caledonia, were treated in Australian smelting works furthermore, Australian mine managers and miners have from time to time been connected with New Caledonian mining ventures, but, unfortunately, it must be said that nearly everyone of them returned to Australia thoroughly disgusted with his experience over there. Even to the casual observer, it is not so very difficult to find a proper explanation for these shortcomings in the peculiar economic conditions of the 'French colony, as many of the objections which have hitherto existed in connection with mining operations, were the direct consequences of a system of colonisation which could not possibly have been productive of better results.

Jan 1, 1901

Much interesting data on cemented carbides has been published over a period of years which, when classified and pieced together, gives a clear picture of this special branch of powder metallurgy. This is an attempt to present the essential information in an ordered account.THE HARD CARBIDES-THEIR PROPERTIES AND PREPARATIONThe so-called hard or refractory carbides are the carbides of a number of metals which are grouped together in the Periodic Classification. These metals are in groups IV, V and VI. They are titanium, vanadium, chromium, zirconium, niobium (columbium), molybdenum, hafnium, tantalum and tungsten. These carbides have attracted the attention of chemists because of their remarkable properties. They possess very high melting points, and are rather difficult to prepare in the pure state. Their outstanding propertyis their extreme hardness, which they share with certain other carbides, such as those of silicon and boron. In addition, these compounds possess distinctly metallic properties, such as lustre (in fused specimens) and high thermal conductivities.(l)t They are capable of forming alloys in two ways:1. With metals, particularly those of the iron group. 2. With each other (a case of solid solubility).The constitution of these substances is not that of ordinary salts, which obey the usual valency rules, but must be likened to that of certain intermetallic compounds. Actually they are "interstitial" compounds(2), that is, they are formed from the ordinary metallic lattice by the insertion of the relatively small carbon atoms in the interstices.. The energy required to fill the lattice completely is high, and this explains the difficulty often found in obtaining the exact stoicheiometric compound. Thus the carbides can have a range of composition, and can be considered as solutions of carbon in the respective metals.Physical Properties of the CarbidesThe hardness of these compounds is so great that it is difficult to compare the individual compounds on this basis. Becker(l) gives values on Moh's scale, which are not very accurate and are of no great value. Burden(3) has reproduced a diagram by Hatfield which indicates that the cemented carbides are between 1,400 and 2,000 on the Vickers diamond scale. However, the pure carbides are harder, tungsten carbide being about 2,200. Hoyt(4) describes a method of measuring hardness applicable to powdered specimenswhereby the powder is rubbed on a standard block of cemented tungsten carbide under standard conditions, and the rate of wear is determined. In...

Jan 1, 1942

By A F. Wilson

The use of stable isotopic measurements as a technique for elucidating the origin and history of the water in hydrothermal fluids is relatively new. Recent studies have emphasised the importance of meteoric water in the formation of many hydrothermal ore deposits including many epithermal gold-base metal deposits which occur in faulted volcanic terrane. Other vein-type gold ores are believed to have formed from fluids of magmatic or metamorphic origin and exhibit characteristic d180 values. These values also give information regarding temperatures and the degree of equilibrium. Preliminary oxygen data for some important gold deposits of eastern Australia are evaluated in the context of styles of mineralisation.

Jan 1, 1980

By Innes J. A

The structural variations occurring in pellets of finely divided mixtures of iron ore and coke breeze, metallized by firing at elevated temperatures, have been examined microscopically. For any given pellet composition, time and temperature are the two most important factors in determining the development of the bonding processes.INTRODUCTIONThe success of sintering and pelletizing processes in the agglomeration of fine iron ores for blast furnace use has brought about rapid changes in thinking relative to methods of preparing furnace burdens. Increases in productivity with the use of sinter emphasize the advantages of a stable, uniformly sized furnace feed. Current practice is to produce a self-fluxing sinter containing most of the lime requirements of the furnace incorporated as a stable medium (Figgis and Charker, 1962). The elimination of fine material from the burden allows greater stack permeability and smoother operation.Sintering and pelletizing of iron ores with or without the incorporation of fluxing compounds has conditioned operators to the extent that it is now considered possible that all components of the burden may eventually be beneficiated in one form or another. Investigations are in hand to improve the quality and sizing of coke, which occupies the major part of the burden volume (Callcott, Innes and Brown, 1961; Innes, Gregory and Worner, 1963). Interest is also being revived in methods of pre-reducing iron ores prior to charging to the furnace (Hansen, Melcher and Fine, 1961). Recent experiments in a small experimental blast furnace (Melcher, 1963) show that charging of semi-metallized pellets can give rise to a production increase of 55 per cent...

Jan 1, 1963

By R J. Merchant

The Hauraki goldfield is located east of Auckland in the North Island of New Zealand. It includes Great Barrier Island, the Coromandel Peninsula and the Coromandel and Kaimai Ranges as far south as the town of Te Aroha and south east to Te Puke. It has a total north-south extent of about 180 km and an area of 3000 km2. The goldfield is the most productive in New Zealand, and while production at present is negligible, the area has undergone continuous exploration over the last seven years.

Jan 1, 1984

By Worner H. K

Education has always been a topic to rouse the interest of mining and metallurgical engineers, but the recent activities of the Education Committee of the Australasian Institute of Mining and Metallurgy 1, 2, together with the moves throughout the Commonwealth to extend the field of technological education, have made the subject a very live one at the present time. The authors have felt it would be appropriate that on the occasion of the First Ordinary Meeting for 1950, in Victoria, some contribution should be forthcoming concerning the history, present status and possible future trends of mining and metallurgical education in this State. As for the past, the time approaches when there will be none having personal recollections of the beginning of Victorian mining schools or of the men who started them. As for the future, it is obvious that rapidly expanding metal-producing and metalconsuming industries will demand a greater output of competent graduates and diplomates. The era immediately ahead seems to be bristling with opportunities, but mining educators need to temper their enthusiasm for various policies and programmes with the realisation that they are helping to train men who will be leaders 15-20 years hence when the problems of industry and trials of life generally may be very different from what they are to-day.

Jan 1, 1950

This paper sets out to discuss how alluvials - particularly mineral sands, tin and gold have adjusted to meet the problems of lower grade and more difficult physical political and economic conditions. The mineral sands industry seems to have adapted satisfactorily but less so with tin and gold.

Jan 1, 1996

A GREAT deal of attention has lately been given to the discussion as to the education required for engineers, and especially for mining engineers. The Institute of Civil Engineers has had a committee's report on it which has come to some interesting and valuable conclusions.The Institute of Mining and Metallurgy had a few years back a very long discussion on the subject, and the subject appears to be one of perennial interest to similar societies. Two recent addresses by Prof. Kernot, as president of the Victorian Instituteof Civil Engineers, are among the most interesting and practical of the contributions to the discussion. Engineers seem to feel either that the coming generation has not the same capacity to benefit by the training that has made themselves what they are, or that such training has turned out in themselves inefficient men, and that they must consequently struggle to obtain a better one for their successors. For not only is there a desire to extend existing instruction to cover the advances of science, but there seems to be a general desire also to make a completely radical change in the methods.It is not necessary to observe that education does not mean the imparting and acquiring of information, but rather the cultivation of the faculties so that the best use can be made of them and of any information acquired. For instance, a man is not educated who has by heart his lectures and the contents of his text-books, but that man is who remembers little of the actual wording of his text-books, but is able to find anything required in them...

Jan 1, 1909

Gold mineralisation at the Macraes Gold Project is hosted in the Hyde-Macraes shear zone and can be traced for ~30 km along strike, although economic resources are confined to a seven kilometre section in the vicinity of the Macraes  township. The shear zone, which typically dips at a low angle (~20¦) to the NE, is bounded by an upper hanging wall shear and a lower footwall fault. Mineralisation occurs along the hangingwall of the shear zone as well as in low angle concordant shears and stockworks. Ore types include graphitic cataclasites with variable amounts of quartz veining, 'lode schists' and quartz-vein stockworks. Mine geology and grade control activities are designed to ensure accurate definition of ore and waste as well as the accurate prediction of ore grade. Grade control involves an integrated process of blast hole sampling, geological mapping and geostatistical modelling. Geological mapping is carried out post blasting by means of excavating trenches across are zones defined by assay data. Conditional Simulation is used to model raw assay data to define ore-waste contacts and estimate ore block grade, although, geologically defined contacts have precedence. Low angle ore zones impart a wedge shaped geometry to many ore blocks. These ore blocks are bounded by contacts that can be selectively mined to, thereby reducing misallocation of ore and minimising grade dilution.

Jan 1, 2001

Flotation of Phosphate Gangue from Magnetite Fines - Non-Ionic Surfactant as Atrac Collector Modifier

Sep 13, 2010