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By Bigdy D. N

The paper describes a system for providing mine management with a continuous indication of the effectivness of longwall coalface powered supports in controlling roof-to-floor convergence. The system comprises on-face instrumentation monitoring convergence and support leg circuit pressures, a means of transmitting the output of that instrumentation to the surface for collection, and software which presents both a condensed analysis for rapid review of the current state, and extended analyses from which remedial action can be recommended if a problem is identified. The results of a field trial are presented showing that meaningful results can be obtained.

Jan 1, 1988

Brief descriptions of several types of unit pulverizeI' are given and the functioning of the components that crush, carry, dry and classify the coal is considered. A distinction is drawn between pulverizers which crush particle beds and those .operating by free-crushing. The overall performance of pulverijlers is considered in terms of correlations between mill variables, coal grindability, abrasiveness, moisture and particle size. Brief discussioiJ. of the influence of pulverized fuel quality on boiler operation and of pulverizing costs concludes the paper.INTRODUCTIONModern coal pulverizers function as carriers of materials and as crushers, as dryers and as size classification machines and, thus, the unit pulverizer comprises. several components that normally function as separate apparatus. The controls of the unit pulverizer must have sufficient flexibility to accommodate rapid variations of boiler load or coal quality. Further, the machine must be robust, yet easy to maintain preferably at annual intervals-so that maintenance costs are small (for coal is a relatively cheap material). Usually, the full load of a modern pulverized-fuel fired boiler can be raised with one pulverizer off-line. All coals, from anthracites to brown coal, may be prepared as pulverized fuel (hereafter P.F.) .Each pulverizer of a direct-fired boiler has, broadly, to supply the burners with coal powdered so that about 80 per cent passes a 200 B.S. sieve and only a small proportion, less than about 10 per cent, remains on the 100 B.S. sieve. The classification processes must prevent any appreciable proportion of coarse particles in the P.F. and yet not return excessive proportions of "finished" fines. The quality of the P.F. should not vary greatly with output rates which may be anywhere between the maximum rate and one quarter ofthe maximum. The suspension of P.F. in the primary air...

Jan 1, 1957

By P Lever, D Hainsworth, H Gurgenci

The ACARP Landmark initiative has created the opportunity to advance the level of automation in the coal industry by first focusing on the core production area of longwall mining. A Landmark Longwall Automation project was commenced in July 2001. The major outcome of automation using on-face observation has been divided into ten outcome areas that have been fully scoped for a three-year initial project life. A major facilitating technology has been the implementation inertial navigation system (INS) technology that can map the shearer position in 3D. A focus of the project is to deliver a system that is at least as productive as the current most productive manually controlled longwall face.

Jan 1, 2002

Analysis of Electrostatic Separation for Rutile Cleaning Duty Using a Plate Electrode Assisted High Tension Roll Separator A plate assisted electrostatic high tension roll separator has been used for the removal of impurity mineral grains from a rutile rich product stream. A laboratory study and a subsequent production study explored the effect of machine conditions with a view to the optimisation of the separation performance of the separator. The performance requirement was that the TiO2 grade in the non-conductor stream was to be less than ten per cent whilst at the same time the ZrO2 grade in the conductor stream had to be less than 0.5 per cent at mass recoveries of greater than 90 per cent to the conductor stream and less than 5 per cent to the non-conductor stream. Mineralogy data was utilized to determine the feasibility of achieving the production targets with the feed under study. Since the feed stream mineralogy was dominated by rutile, leucoxene and zircon, it was possible to use an approximation to the actual mineral assemblage as well as the raw X-ray fluorescence data to understand the separation duty of the Carrara machine. Since there were four conflicting criteria used for the performance requirement, an index was devised that incorporated all the requirements simultaneously. This new index was the sum of the squares of the difference between the achieved and desired values, weighted with respect to the variance of each variable. If the desired value for a particular criterion had been met its contribution to the sum was set to zero, no matter how well the criterion had been met. For the production machine the strict requirements were almost achieved. As expected, the achievement of the target performance was dependent of the feed conditions at the time of measurement. This paper reports the results of this study.

Sep 13, 2010

By Madgwick J. C

Four manganese dioxide leaching microorganisms, an Achromobacter spp, Aspergillus niger, Elllerobacter cloacae and Elllerobacter agglomerails were purified from sucrose enriched crude mixed cultures which contained at least sixteen, non-leaching, morphologically different, colony types. Fastest leaching rates were obtained from the original enrichment's mixed cultures (1.26 g Mn++ I/d) while best yields of Mn++ m terms of sugar use came from Achromobacter and A. niger being 0.84 and 0.89 g Mn++/g sucrose respectively. The peak efficiency in manganese reduced, per carbohydrate used, coincided with the exponential growth phase for Achromobacter. The two Elllerobacter species performed better in stationary or senescent growth phases.

Jan 1, 1985

Study on Influence that Styrene-Phosphoric has on the Surface Property of Rutile Minerals

Sep 13, 2010

Modelling Channel Scale Flow in Heap Leaching Using Smooth Particle Hydrodynamics (SPH)

Sep 13, 2010

Sulphuric acid leaching at atmospheric pressure of a number of Australian nickeliferous laterites was examined in detail. The results obtained indicate that nickel can be extracted from these ores, although the conditions required to achieve about 90 per cent extraction vary widely. These differences in reactivity can be related to the types of nickel-bearing minerals present.Nickel is more readily extracted from nickel-bearing clays such as chlorite, than it is from nickel-containing goethite.The results clearly show the problems associated with the processing of complex ores such as the nickeliferous laterites, and they indicate the need for complete characterization of each deposit.

Jan 1, 1978

It is a pleasure and a privilege to be with you for the Annual Conference of The Australasian Institute of Mining and Metallurgy.The inaugural meeting of The Institute was held in Adelaide in April, 1893. Through the kindness of your President, who passed on to me several publications concerning The Institutute I have been able to glance back over the eighty years in which The Institute has served both the profession and Australia.In that record, many names of great distinction caught my eyes. When one reads the list of past presidents of the The Institute since 1893 and the list of those to whom The Institute Medal has been awarded, one reads the headings of a biographical dictionary of the Australian mineral industries. Many famous names are there-men from the great mining companies, engineers, scientists, metallurgists and geologists. Simply to read the names is to recall great enterprise and great achievement. Going over those names one hears the echoes of the inspiring story of the establishment of the Australian steel industry, the electrolytic zinc inq.ustry, all the major developments in the mining of coal, gold, copper, silver and lead, the treatment of difficult ores, the geological exploration of a cqntinent, the discovery of uranium, bauxite, petroleum, nickel, the establishment of the alumina industry and finally the mammoth earthmoving operations of today. The list of names is a chronicle of great men who did a mighty work. They stand like milestones in the progress of a nation.When one reads further and runs down the titles of some of the papers published in the Proceedings of The Institute even a layman like myself can appreciate the dramatic developments in mining and metallurgy that have transformed the whole practice of the mineral industries in our land. Australians have made some notable innovations and discoveries both in mining techniques and in the processing of ores. The history of mining is not only a story of the discovery of the mineral resources of this continent but of adventurous steps taken to perfect new ways of mining the ore and extracting the metal.I read with great admiration the presidential address given by Sir Maurice Mawby in 1968 and wa...

Jan 1, 1973

Regions with extensive reserves of brown coal but with inadequate deposits of hard coal provide a particularly suitable field for the application of brown coal petrology.In fact, this discipline is indispensable where brown coal is to form the basis for high-quality products of upgrading. Both chemical and physical analyses are required in addition to the techniques employed in coal petrology, but it is the macropetrographic and the microscopic investigations that are of decisive and specific importance.Foremost among the methods of upgrading brown coal is briquetting. From the raw materials aspect the biochemical rank of coal (i.e. the type of deposit) and the coal variety (i.e. the lithotype) exert a marked influence on briquette strength. These are also the significant factors in the suitability of a brown coal for high temperature carbonization; here the demands on coal quality are even more exacting if adequately sintered and therefore high-strength lump chars are to be obtained. The principle applies also to the char from low temperature carbonization. There are close relationships between the tar yield and the remission of the coal.The reflectivity measurement therefore provides a rapid method for evaluating the suitability of a brown coal for low temperature carbonization. Similar correlations have been established between the content of extraction bitumen (raw montan wax) and the remission. Petrological investigations show that the quality of the coal bitumen is a function of the type of deposit and of the lithotype.

Jan 1, 1968

By N J. Grigg

Gekko Systems has developed an underground pre-concentration plant (Python) to reduce mine operating costs. Many ores liberate favourably using either high pressure grinding rolls (HPGR) or vertical shaft impactors (VSI). Using these comminution circuits for mineral liberation; rather than for the final recovery process and by utilising a high mass pull, high recovery process route (gravity/flotation), a narrow, low head, compact processing plant was developed that can sensibly be operated underground. The Python underground processing plant can provide a number of advantages for narrow vein mines including lower haulage costs, improved mine call factor and lower operating costs. The focus on fine crushing reduces the power requirement of the plant to approximately 8 kWh/tonne. The Python underground processing plant has been designed to be towed down the decline or lowered down a shaft, and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a saving in mining costs and a significantly smaller environmental footprint.

Jan 1, 2008

By M J. Begbie, P C. Keall, M P. Simpson

The Golden Cross low sulfidation epithermal deposit occurs in pervasively altered andesite of the Waipupu Formation and in the Waiharakeke Dacite. The unaltered, post-mineral Whakamoehau Andesite overlies these units. The Empire zone of the Golden Cross deposit contains a stockwork which is currently mined by open pit methods, and a series of veins that are mined underground. Alteration envelops both the underground and open pit mineralisation. The core of the alteration zone contains silicification, as quartz veins, and adularia. Shallow portions of the system contain illite-smectite and a thermally unstable chlorite, tentatively identified as corrensite, which pass downward into illite and chlorite, respectively. Replacement calcite occurs widely throughout the altered zone; pyrite is nearly ubiquitous. This alteration assemblage indicates formation from near-neutral alkali chloride waters. A late, post-mineralisation alteration assemblage of calcite, smectite, illitesmectite, kaolinite and siderite presumably formed from weakly acidic, steam-heated CO2-rich waters.   We have identified eight stages of vein formation: (1) sulfide veins, (2) black veins, (3) massive veins, (4) banded veins, (5) thin white veins, (6) crumbly veins, (7) massive/platy calcite veins, and (8) flattened rhomb calcite veins. Gold mineralisation occurred relatively early in the lifetime of the system, dominantly during 2 through 4. The late calcite veins (7 and 8) and early sulfide veins (1) are barren.  

Jan 1, 1997

Chalcopyrite concentrate was combusted in oxygen-nitrogen atmospheres, the composition of which ranged from 1-100 per cent oxygen. Factors studied included particle size, experimental temperature and oxygen concentration. The study was assisted by chemical and X-ray diffraction (XRD) analysis and temperature measurements of single particles. Size reduction occurring after melting was found to have a major effect on the overall reaction time. Thus time to attain ignition was largely determined by the original particle size, whereas combustion time was independent of this factor. For particles larger than 40 I'm in air the time to attain ignition predominated. The maximum temperatures measured for single particles were the result of pyrite present in the concentrate. Chalcopyrite did not attain thesame temperatures. Vaporization, either as CU(g) or CuO(g) lImited the temperature. Maximum temperatures measured for single particles of pyrite ranged from 1610°C in 14 per cent oxygen to 2360°C in 100 per cent oxygen (both at 700°C). Measured temperatures were compared with those calculated from a diffusion-based model.

Jan 1, 1983

By Waugh D. M

investigations have been undertaken into the flow characteristics of mineral slurries from a number of Australian metallurgical plants including Mount Isa Mines Ltd., North Broken Hill Ltd., and Broken Hill South Ltd. Experimental equipment installed for this work included facilities for continuous recording of flow rate and pressure drop and detection of sedimentation.Although the method has subsequently been described in published literature, it is believed that the investigations included the original application of a method for correlation of the flow rate and pressure drop data. This method depends on solving by graphical methods the values of the constants k, and c in the relationship EQUATION 1 where D is pipe diameter; ?P, pressure drop; L, length; and V, mean linear velocity. Discussion of this correlation also reveals why sedimentation velocity does not necessarily vary greatly with pipe diameter.INTRODUCTIONIn order to design pumps and pipeline installations for a Newtonian fluid, measurements of the fluid's density and viscosity in any of a number of instruments are sufficient. Substitution of these values in well known equations to calculate Reynolds numbers and subsequent correlation to determine friction factors are all that is required for engineering specification.As a result of work during the last decade, particularly that of Metzner and Reed (1955) and Dodge and Metzner (1959), it is now possible to design for homogeneous non-Newtonian fluids using relatively simple instrumental measurements.These methods can sometimes be applied to thick slurries which behave as if homogeneous. However, for the...

Jan 1, 1965

By Jaczkowski B

The lower orebody (LOB) at Chingola Divi- sion of Nchanga Consolidated Copper Mines Limited (NCCM) accounts for approximately 30 per cent of the total copper production for the company. The uniformity of the geology of the orebody lends itself readily to a computer based ore reserve calculation and accounting system. The mining units are physically defined such that a hierarchical type of com- puter file organisation can reflect the existing physical interdependencies. In 1972, a project team consisting of one representative from each of the mine planning, operational research, and computer services departments was formed to investigate and to define the technical mining requirements of the dynamic ore reserve system (DORS). The system was finally implemented in 1975ò

Jan 1, 1977

By Wiechers HNS

In China the hydrogeological type of solid mineral deposits can be divided into A. Mineral deposits with fissure water; B. Mineral deposits with pore water; and C. Mineral deposits with karst water. The hydrogeological conditions of mineral deposits with fissure water are relatively simple with the exception of a few cases. Mineral deposits with pore water are few but great amounts of ground water can be encountered in the mine accompanied by floating sand or slope failure during the exploitation. Mineral deposits with karst water are complex in their hydrogeological conditions. Enormous inrushes occur frequently in the mines of north China; Karst collapses are a serious matter in the mines of the south; Subterranean river and conduit systems are often encountered in the southwest. This paper will give full discussion on these features and put forward a way of combating and controlling the groundwater problem in accordance with type and feature.

Jan 1, 1988

This paper aims to collate the metallurgical test work undertaken on the Barrytown mineral sands deposit. It is intended to serve as a summary of mineral dressing work undertaken by all interested parties up to the time of writing. Areas requiring further investigation are: in situ grades and recoveries of accessory minerals,the question of 'rank' of ilmenite within the deposit,flow sheet development for the recovery of gold and monazite, andcost analysis to investigate the relative worth of other minerals; notably rutile. Flow sheet development with respect to the Accessory Minerals cannot be accurately defined until the importance of each mineral in terms of grade, recovery and expected revenue is determined. To date, ilmenite and zircon flows are well documented. Further work is needed to quantify recovery's and flows of the other minerals; notably monazite, gold and rutile.

Jan 1, 1989

The Autogenous Fine Grinding Kelsey Axial Displacement (KAD) Mill The marginal improvements which continue to be made to fine grinding practices have exposed the limits of conventional technologies and highlighted the need for a radically new approach. The patented autogenous Kelsey Axial Displacement (KAD) Mill design consists of a rotating spherical grinding chamber, which shares the same spherical centre as the shaft-mounted counter-rotating disc assembly. The axis of the disc assembly can be inclined to the axis of the spherical grinding chamber by pivoting the disc shaft about the common spherical centre. The inter-particle energy transfer required for breakage results from particle velocity differentials created by the discs intercepting the rotating mass. Particle size reduction is concentrated in high shear zones, which envelop the outer surface and periphery of the discs. This paper traces the development of the KAD Mill from pilot to commercial scale. Pilot work covers a range of minerals including magnetite, calcite, dolomite, barite, limestone and talc. Test results include open and closed circuit operation in wet and dry modes. Conventional milling constraints and energy consumption issues are addressed while new dimensions are added to the feed size range acceptable for wet and dry grinding to fine and ultra-fine sizes.

Sep 13, 2010

Silver is one of the three major metals produced from the Broken Hill mines. The accurate determination of the silver in these ores, therefore, is of economic importance.With due appreciation of the divergence of opinion of many who are interested in the subject of the determination of silver, the writer has been prompted to present the results of some recent experiments on silver losses during cupellation and conclusions from these experiments in the present paper. The losses of silver in the fire assay for this metal are due to silver retained in the slag during the fusion or scorification of the ore, and to silver volatilized from, and absorbed by the cupel during the process of cupellation.The literature describing the results of experimental work on silver losses due to the above causes is extensive, and the general conclusion of these experiments is that the silver lost in the slag is small, but that lost by cupellation is larger and more variable.The term cupellation loss in this paper refers to the total cupellation loss, no distinction being made between the absorption and volatilization losses.Volatilization loss is shown by King to be 0.5% of the total cupellation loss and, as it is generally accepted among assayers as being only a small fraction of the cupellation loss (3) (5), it will not receive further consideration in this paper.The factors causing the loss of silver by cupellation and the precautions to be obs~rved to reduce the loss in this operation are described in (1), (2), (3), (4) and (5). The...

Jan 1, 1940

By A M. Purba and A Sjadat, A D. Wilson

Ongoing mining of the East Ertsberg Skarn System orebody below the Gunung Bijih Timur and Intermediate Ore Zone caves has been relatively successful and a ramp up to 80 000 t/d was achieved in the Deep Ore Zone Mine. However, the distribution of production, the overall drawpoint availability as well as the rate of change of the cave back profile has not followed the anticipated path. Several key factors influencing cave growth and progress, grade variation, fragmentation, wet muck and surface subsidence have been recognised over the life-of-mine that now have to be taken into account for planning the later stages of mining.The paper will discuss the influence of geological controls of lithology and structure – how this as well as other contributing aspects have impacted ore flow, contributing to some of the widespread panel damage, and been a key factor in compacted draw columns and caused an accelerated appearance of water ingress. This in turn has rapidly changed the distribution of wet drawpoints requiring remote mucking and special controls that also affect the call from the remaining dry drawpoints. Comment is also made on the potential final cave profile if it continues along the current trend and some discussion is offered about possible mitigation measures if this were to come about.CITATION:Wilson, A D, Purba, A M and Sjadat, A, 2016. Progressing cave performance into the later stages of the Deep Ore Zone mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 285–292 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016