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By Poi G, Madgwick J. C, Davis P, Pannowitz D, Cho D, MacKay B, Chan S. M, Varga R. A, Chun U

Periodic dilute sulphuric acid treatment ofstill, batch-fed, molassesenriched, microaerobic, manganese-dioxide-Ieaching microbial cultures led to marked improvements over untreated cultures. Percentage Mn++ recoveries increased (7X), rate of Mn++ formation improved (3X) and yields of Mn++ per molasses use were more economical (5 X). The yield in terms of molasses used improved with decreasing sugar used (eg 1.17 g Mn++/gram molasses at 0.2 per cent molasses (w/v) feed and 24 per cent (w/v) pulp density MnO2 tailings). The most effective Mn++ leaching in terms ofpercentage recovery (97 per cent) and rate ofleaching (46 mg Mn++/day) was at 0.5 per cent molasses (w/v) and 14 per cent pulp density (w/v) MnO2 tailings.

Jan 1, 1986

By P Vasconcelos, X D. Deng

Numerous supergene manganese oxide deposits are developed inSouth China as a result of weathering of a thick sequence of Paleozoic marine Mn-bearing sedimentary rocks, consisting mainly of limestones, cherts and black shales that were intensely folded and faulted due to multiple episodes of tectonism since the late Triassic. The ore minerals are dominantly pyrolusite, cryptomelane, nsutite, lithiophorite and braunite. The supergene manganese ores contain Mn ranging from 20 to 44 wt per cent; manganese oxide deposits derived from cherts and black shales also contain recoverable levels of Co, Ni, Cu, Pb and Zn. 40Ar/39Ar dating of potassium-bearing manganese oxides reveals that extensive supergene manganese ore formation started at least in the earliest Miocene and persisted to the Present. Ages of the deposits show a close correlation to tectonic stability, with the oldest in tectonically quiescent areas and the youngest in active areas that have subjected to continuous uplift and thus significant denudation. The prolonged wet and hot climate since Oligocene and the balance between weathering and erosion, which is parameter to the tectonic stability, are the ultimate controls on the formation and distribution of South China supergene manganese oxide deposits. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Ultrasonic Extinction for High Resolution Particle Size and Concentration Analysis

Sep 13, 2010

By B Murphy

Traditionally comminution optimisation has been focused on energy minimisation, whereas flotation optimisation has been focused on recovery improvement. One of the largest, if not the largest, operating cost over the life of a flotation circuit is electrical energy. With increasing pressure on operators to lower production costs and the cost of energy increasing, reducing the energy consumption of the flotation circuit can be beneficial to site economics. This paper reviews the use of energy by mechanically agitated flotation machines and discusses the measurement and benchmarking of energy consumption in modern flotation concentrators. Opportunities for improving flotation energy efficiency are also identified.CITATION:Murphy, B, 2013. Flotation energy consumption and opportunities for improvement, in Proceedings MetPlant 2013 , pp 399-412 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By J Carrillo, A King

Gravity recoverable gold (GRG) is largely distinguished from other gold by its non-mineralised, metallic form, its high degree of liberation from the ore and its appreciable particle size. The gold mining industry has so widely accepted the use of batch centrifugal concentrators (BCC) and intensive cyanidation (IC) systems for the recovery of GRG that these may well be considered requirements of any plant processing ore containing appreciable GRG. The recovery of gold by gravity is quick, easy and cheap by comparison to alternatives. However, there are cases where attributes of the ore make recovery of gold by gravity and IC unusually challenging. This paper describes three examples where such challenges have been encountered and met, including those where the ore contains cyanide soluble base metals and where fine GRG is to be recovered from flotation concentrate.CITATION:King, A and Carrillo, J, 2018. Addressing challenging applications of intensive cyanidation in gravity gold recovery, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 283–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

Large scale fluid extraction from the Latrobe Group in the Gippsland Basin is occurring as a result of offshore petroleum production and coal mine dewatering in the Latrobe Valley. Groundwater extraction in the Latrobe Valley exceeds recharge and is causing an expanding area of declining hydraulic head in the Latrobe Group, and regional land subsidence which is well documented. Recently the government water sector completed the installation of a network of Latrobe Group monitoring bores in the remainder of the onshore part of the Gippsland Basin. The bores situated along the coastal area show a steady decline in hydraulic head of about 1 m/year which can be attributed mainly to petroleum production.

Jan 1, 1992

By Tripathy A. K, Satapathy B. K, Nayak B, Mohanty J. N, Dey D. N

The paper deals with the metallographic tudy of heat treated chromite and chromite-coke composite briquettes. The briquettes, prepared from chromite concentrate of Orissa Mines using molasses-lime, dextrinelime and tamarind seed as binders, were subjected to different temperatures and examined metallographically. The change of phase with temperature was analysed by X-ray diffraction.

Jan 1, 1987

By I Halikia, T Lilis

Lead smelter slags, produced during the last century in quantities ofmillions of tonnes at Lavrion, Greece, have recently been used in theconstruction of Lavrion harbour. In order to evaluate the geochemicalstability of slags and assess their environmental impact on the aquatic environment, a detailed study on lead leachability under conditions that simulate subsea environments was carried out. Leaching experiments using magnesium chloride solutions under mild temperature conditions were conducted and the effect of main parameters on lead solubility was examined. Furthermore, kinetic analysis on the experimental results was performed. Based on the results, lead dissolution increases by increasing the reaction time, magnesium chloride concentration in the bulk solution and temperature, whereas it decreases by increasing the slags particle size. The reaction order was found to be approximately 0.5 at the initial extraction stages and the activation energy value from the Arrhenius plot was estimated to 29.8 KJ/mole. Diagnostic equations applied to all the experimental data reveal that lead dissolution is mainly controlled by diffusion through the ferrosilicate matrix of the slag particles, which is in accordance with the low activation energy value. The JanderÆs diffusion equation [1-(1-a)1/3]2=kt was proposed as the equation representing the reaction of lead dissolution from slags using magnesium chloride solutions.

Jan 1, 1999

The structure of the Bulli coal seam at Appin Colliery was detailed by the seismic reflection method. This unusual application of the seismic method was possible because there is a reflector near the seam as was revealed during exploration for petroleum in an area north-west of Appin. The reflector, which was at a depth of 1,500 ft, was shallow by normal reflection survey standards. Measurement of the seismic velocity at two ventilation shafts showed that the reflector was probably the Bulli coal seam. Accurate depth control was established from previous drilling results.INTRODUCTIONAppin Colliery, situated on the Southern Coalfield of N.S.W. (Fig. 1), is being developed to supply coking coal to the Port Kembla steelworks of Australian Iron and Steel Pty. Ltd. The colliery is mechanized and a detailed knowledge of structure, particularly faulting, is important in planning the workings.The Bulli seam, which is approximately 9 ft thick, and between 1,500 ft and 1,800 ft below the surface, is worked in the colliery. It is the uppermost member of the Permian Coal Measures and is overlain by Triassic rocks, which consist of thick sandstone beds containing beds of coloured shales, and which are subdivided into the Narrabeen Group, the Hawkesbury Sandstone, and the Wianamatta Group.In the early stages of development of the colliery, surface geological mapping and diamond drilling provided information on structure. Generalized results of the mapping are shown on Fig. 2. Drilling indicated that the physical and chemical properties of the Bulli seam are relatively constant, and that the seam is nearly horizontal, the average dipbeing about 1 in 25 to the west.

Jan 1, 1965

It has been proven theoretically and experimentally that the use of 10 - 30 per cent DRI in blast furnace along with iron ore or sinter results in lower coke rate and higher productivity. However, to-date this remains unpractised on a regular basis mainly because of economic reasons. The DRI produced by several methods are expensive and difficult to store/handle in large quantities because of its reactive nature and thus DRI in blast furnace remains unacceptable.

Jan 1, 1999

ALTHOUGH great progress has been made in flotation of the Broken Hill silver-lead-zinc ores, no paper dealing with this subject has been presented to the members of the Institute since James Hebbard's valuable contribution in 1913. Almost every discovery or development in the history of flotation has formed the basis 6f a patent, and but few experimentalists have overlooked the fact that their investigations might lead to the establishment of a patentable process. This, together with the aftermath of patent litigation, naturally resulted in secrecy being maintained in matters appertaining to the art, and the industry as a whole has consequently suffered considerably. Much valuable time has been wasted through numbers ofmen repeating work along certain lines, which, unknown to them, had already been thoroughly exhausted by others, whereas a lot of this would have been avoided by a freer interchange of information amongst those directly concerned. Owing to differences in the ore treated and the various applications of flotation concentration in relation to gravity methods, the flotation problems of the various mines differ considerably. This, together with the secrecy previously referred to, hasresulted in the development of numerous systems and machines, most of which would appear, to the casual observer, to comprise separate and distinct processes. The author has endeavoured to show how much these processes have in common with one another, and, at the same time, has tried to convey some general ideas on flotation to those members of the Institute who are not directly associated with this branch of concentration.

Jan 1, 1919

Additional Attractive Force Between Alumina Particles Due to Low Solubility of Dicarboxylic Acids

Sep 13, 2010

Common brattice cloths in use in Australian coal mines are compared by permeability measurements. The respective advantages of twill weave and tarpauling* weave cloths are listed, and the improvements to be obtained in the ventilation of a mine by using tarpauling cloths instead of the commonly used twill cloths are stressed. Plastic cloths are widely used overseas and are briefly discussed.INTRODUCTIONThe onset of extensive full-scale mechanization in Australian coal mines during the past few years has increased attention given to the ventilation of working places. Many inadequacies of the present system have been brought to light and not the least of these is connected with the use of brattice cloth, both in directing the flow of air around the face and in acting as a temporary sealing mechanism. A well-constructed line of brattice will only provide fair ventilation for a distance of 100 ft. Beyond this point the volume or air reaching the face falls off rapidly.Some of the shortcomings associated' with the use of brattice cloths are:1. Hurried installation, necessitated by a rapid advance, often results in poor workmanship with, consequently, an excessively high leakage rate.2. High places caused by falls of roof are difficult and time-consuming to seal.3. Curtains, in lines of brattice crossing transport routes, are difficult to maintain.4. Lines of brattice interfere with rock-dusting and clean-up of fine coal.5. Repair and maintenance of brattice consumes much...

Jan 1, 1959

The importance of the Broken Hill mining field may be gauged from the fact that since the discovery of the ore-body in 1883, till the end of 1931, approximately 43,000,000 tons of ore have been raised.The lode covers a length of 31 miles, and in places is upwards of 300 ft. in width. The ore, as at present mined, consists of an intimately blended mixture of lead and zinc sulphides with silver and gangue minerals.Structurally the lode conveys the impression of a huge longitudinal arch (when viewed from the east or west), having its apex or crown near the centre of the field, in the leases of the Broken, Hill Proprietary Co. Ltd., where the lode outcropped at the surface.The minimum depth of the lode in the Proprietary mine was some 500 ft. from the surface, but huge undulations, having an average pitch of 45°, carry the extensions of the arch gradually deeper, to those places where active stoping operations are now in progress in the workings of the North mine at one extremity, and the South and Zinc Corporation mines at the other. The depth of the lode from the surface, as exposed at present, is approximately 1700 ft. at these extremities.The structure and physical character of the ore-body, and its containing walls, are so complex and varied that almost every type of mining problem is met with.

Jan 1, 1932

The nature of the specialty glass and ceramic business magnifies the dependency of the ultimate product on the unique properties of their raw materials used to make them. This dependency has implications in the management of risk in the supply process which requires a special procurement organization and program commitment to be successful. The Coming system of managing critical materials and factors in development of alternate new suppliers and products is discussed.

Jan 1, 1989

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

Mineral Changes that Occur During Coal Gasification

Sep 13, 2010

Modem mineral exploration and development takes place within a data-rich context underpinned by a wide range of data acquisition, processing and interpretation technologies. This leads to requirements for consistent and explicit methods by which the relative risks - or success probabilities - of exploration programs can be assessed and communicated. Bayesian risk assessment methods are outlined which provide a starting point for this more rigorous approach to exploration investment.   Effective governance of information technologies becomes a core function of the modem competitive Board. As such it becomes a component of any business audit and any assessment of the quality and success potential of a company. Limited data however suggest that the average Board may be under-represented in this increasingly critical skill area.

Jan 1, 1997

Effect of Matching Relationship Between Bubble Size and Particle Size on Kaolinite Flotation

Sep 13, 2010

Recently published extensions to the mill-dump cutoff grade theory for joint open pit-concentrator operations lead to equations that must be simultaneously satisfied as a necessary condition for an optimal operating policy. These equations are parametrically dependent upon ore quality parameters, other than grade, relating to the ease of recovery of the disseminated mineral in the concentrator. Since it is not possible to treat quantities of ore corresponding to the size of selective mining units separately in the concentrator some mixing is inevitable and often deemed desirable in the interest of homogeneity of mill feed. This renders the calculation of cutoff grades for individual mining units futile; mining units must be grouped to form larger parcels that can be dealt with separately. In doing so an opportunity cost may be incurred; the loss of potential benefit that would result from such separate treatment. This matter is considered from a theoretical, qualitative, point of view. A numerical example then shows that a significant variability in the quality parameters can be tolerated without incurring such opportunity cost, provided sufficient knowledge is available concerning the distribution and effect of these variables to enable the use of effective mean values of these parameters in the cutoff grade calculation. Lack of such knowledge can have major consequences for the economics of the operation.

Jan 1, 1981