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THE irregularity of the Mount Morgan ore body presents problems other than those for mining only. For irregularity of outline is coupled with irregularity of grade, and the ore varies so rapidly from profitable to non-profitable, and from highly siliceous to highly pyritic, that the task of estimating quantities and values of ore reserves is manifestly rendered a difficult one, while the actual disposal Of the broken ore demands constant supervision.Four classes of ore are handled. The oxidized ore, cheaply mined and cheaply treated, is obtained by quarrying from the top of the mountain. Below the 315-ft. mine level (measured from the original summit) sulphide ore comes in, and this is divided into siliceous sulphide ore (too siliceous for economic smelting), sulphide ore suitable for smelting, and ore too poor either to be smelted or to be treated by wet process with the siliceous ore. It is with these three latter descriptions of ore that this paper principally deals.Although the output from most stopes in the mine may usually be presumed beforehand to be either smelting or wet-treatment ore...

Jan 1, 1910

Rehabilitation, reclamation and restoration are all terms used to describe the repair of land after mining. Here, restoration is used to mean restoring the land's original use, capability or productivity. Effective restoration is dependent on good planning before mining commences and must include a clear definition of post-mining objectives. The physical condition of the land within the mining licence was that of an imperfectly drained soil in permanent pasture, supporting a seasonal supply dairying unit. During the mining process, the soil layers were separated, with the topsoil stockpiled separately. As part of the restoration process, the land was recontoured to encourage surface drainage, with topsoil spread evenly over the recontoured tailings. Low grond pressure machinery was used to minimise soil compaction, with light discing and harrowing used to increase water infiltration. A permanent pasture was sown, with weed species controlled by spraying, both before and after pasture establishment.  Soil testing has been used extensively to ensure there were no nutrient deficiencies that good compromise pasture establishment and performance. Controlled grazing practices were used to ensure that the sown pastures became well established.

Jan 1, 1998

By M R. Stevens

The Kauri Block (Hauraki Hill) andMatawai Valley epithermal vein systems, near Coromandel township, are hosted by hydrothermally altered Miocene andesites and Mesozoic greywackes of the Coromandel VolcanicZone. The hydrological setting of both geothermal systems was probably that of an andesitic volcanic arc. Two types of veins are recognised: 1. Simple veins composed of fine comb quartz, and 2. Complex (breccia) veins composed of vein fragments of sulphide-bearing, chalcedonic silica cemented by saccharoidal and fine comb quartz.   Pyrite, arsenopyrite, marcasite, and gold form the ore minerals. Both deposits historically exploited hypogene and supergene bonanza gold.   At Hauraki Hill, breccia veins up to 7m wide contain abundant fragments of recrystallised colloform banded-crustiform textured quartz veins ('Golden Cross' style) and were probably major channels for ascending deep mineralising fluids. Alteration assemblages are zoned with the higher elevations of Hauraki Hill-Bunkers Hill characterised by strong kaolinite alteration whereas deeper levels are dominated by illitic clays.   At Matawai, complex veins and hydrothermal breccias pinch and swell, and inflect, within a total width of veining and alteration that exceeds 50 m. The greywacke host rocks are altered to an assemblage of illitesmectite, quartz, chlorite and pyrite although there are pockets of kaolinite.   The proposed genesis of veins and ores in both deposits invokes episodic rapid mixing (quenching) of hot mineralising reservoir fluids with cool acid condensate waters, whilst acidification and increased fO2 triggered gold deposition. These hydrothermal systems heated up during their later stages and at Matawai visible gold was deposited from a late mesothermal stage. The main conclusion is that the northwest CVZ has excellent potential for large gold deposits (= 30 tonnes contained gold).

Jan 1, 1993

THE science of topography deals with the various natural and physical features of the earth's surface. These features are determined by the manifold constructive and destructive processes of nature, and their many diverse forms and characteristicsare dependent primarily upon geologic structure. Thus it is that a close relationship exists between the rocks of a region and the topographic features of the lJountry wherein they occur. Again, the existence of all sorts of mineral wealth is dependentupon the nature of the rocks, and their extension is directly connected with the topographic features represented upon the enclosing land-area.In studying any district with a view to deciphering its geological structure, to locating any mineral deposits it may contain, and to ascertaining, so far as a surface-examination may show, their probable and economic possibilities, it is therefore ofprimary importance to have at hand a correct topographical map of the area under investigation.GENERAL REMARKSThe actual amount of topographic detail shown will depend upon the money and time available for topographic surveying and upon the scale upon which the final map is to be produced...

Jan 1, 1912

WHEN making comparisons of the efficiencies of different grinding and crushing machines it is desirable to be able to estimate the work actually done in crushing the ore from a given size of feed to a given size of product, the screen analysis of both feed and product being determined. Messrs. Klug and Taylor, in a paper on this subject, published in the monthly journal of the Chamber of Mines of WA, 31st January, 1906, have described a method adopted by them in calculations made in connection with a series of trials of grinding pans. Their methOd is based upon the assumption that if a quantity Q of material consisting of particles of average diameter x be crushed down until the average diameter of the particles is y, then the work done in grinding is proportional to Q x. There is no theoretical basis for this assumption that the writer is aware of, and it does not appear to satisfy the fundamental conditions necessary. If the material be further crushed until the diameter 2 becomes Z, the additional work done is measured. The work done in crushing from diameter x to diameter Z in one operation is proportional to Q x:, and therefore we ought to have zx2 y2 x2 Q-+Q-=Q-. y2 Z2 Z2But these expressions are not in general equal to one another. In other words, according to the theory underlying this method, if we crush from diameter x to diameter y, and then from diameter...

Jan 1, 1909

With the employment of a system of ore pillars to support the hanging wall during the mining operations at the North Mine, it was found that, when the stopes were worked out and the pillars remained intact, the main footwall drives developed an undulating longitudinal section due to the shrinkage of the filling in the worked out stopes.These depressions collected water, which made the footwall drives very wet under foot, and everitually worked its way into the pillar workings and the levels below.Water was also finding its way into the shafts because of the silting-up of the level drainage systems and, as both the shafts are down-cast, this tended to increase the humidity of the air entering the mine.To overcome these troubles it was decided to try a system of siphons as a method of subsidiary drainage.SYSTEM AT PRESENT IN USE.All drainage water is collected as near to its source as possible, run into a sump in an adjacent low lying part of the level, and continuously removed from these sumps by a siphon system.Each level has its own system. Water is collected from the sumps by a 1-in. pipe and delivered to a pipe running the length of the level along the back of the footwall drive. At the shaft the pipe is increased to...

Jan 1, 1938

If lead buttons are cupelled under closely controlled conditions in a suitable design of furnace, silver losses during cupellation are given by a simple equation. The effect of copper on these silver losses has been studied and a "copper limit" for cupellation has been determined. Scorification and crucible fusion procedures for copper-bearing materials have been designed so that the lead buttons produced will not contain amounts of copper greater than this determined copper limit. Silver losses during these crucible fusion and scorification procedures are given by the distribution law, and can be calculated. Thus, silver can be determined in copper-bearing materials with a satisfactory degree of accuracy provided that the appropriate corrections for losses are applied to the weight of the silver prill produced.

Jan 1, 1957

Few, if any, reliable thermodynamic data are available for the activity of tin oxide in slags. In this work, the activity of the oxide in silica saturated iron silicate slags has been measured at 1573 K using the equilibrium Sn (alloy) + Y2O2-SnO (slag).Slag and a Ag-Sn alloy were sealed in a zirconium oxide crucible to prevent the escape of volatile tin oxide, and the oxygen pressure at equilibrium measured in situ using the zirconium oxide as a solid electrolyte. Activity of tin was calculated from known data for the Ag-Sn system and activity of tin oxide calculated from free energy data. The results have been extrapolated to predict the industrially important distribution of tin and iron between Fe-Sn alloy and iron silicate based slags.

Jan 1, 1983

By Mech B

This paper gives a general description of mining practice at The Zinc Corporation Ltd., Broken Hill, New South Wales.The basic mining methods are those which have been common in Broken Hill for many years and have been well described in previous Proceedings. The main object of this paper is to indicate developments which have occurred in recent years and to describe changes in layout, mining methods and equipment which are taking place at present.The following headings have been adopted: History Geology and general characteristics of the orebodies, Geology, The lead lode, The zinc lode, General characteristics, Ore reserves, General mining method, Exploration and diamond drilling, Shafts and shaft sinking, Main shaft, Old main shaft, Block 5 shaft, New upcast airway, Development, Level interval, Level layout, Driving and crosscutting, Winzing, Rising, and Stope preparation.

Jan 1, 1946

IN concentrating mills, where several millerals are recovered for realisation in more than one product, various systems are used to express the relative economic value of the work done, and, in the hope that it may prove of use to other operators, the writer will describe a system which, in his opinion, is more complete than any other that he has seen published.The controlling factor in all mill work must be based on the economic result represented by the greatest margin possible between the realizable value of the products and the cost of obtaining same.From a mill-man's point of view these are affected by the following factors:1. Metal contents of ore.2. Grade of products.3. Recoveries.4. Working costs.The grade of ore milled is usually outside the mill-man's control, but this may exercise a considerable influence on the grade of his products, metal recoveries, and revenue per ton of ore. Higher grades or recoveries may be obtained by using a more expensive process, or by additional grinding or reagents, and the economic comparison can only be arrived at by obtaining an analysis showing the monetary value of each variation within the possible limits.In the system to be described, the value of unit variations of metal contents of the ore, grade of products and recoveries are calculated in terms of a monetary unit per ton of ore with the returning charges ruling, and any suitable metal prices. To do this it is necessary to assume what, for convenience, is termed a "standard" set of results from the mill, preferably representing about average conditions, and having calculated the effect of unit...

Jan 1, 1931

By Miezitis Y

A weak airborne radiometric anomaly was examined in the field and the presence of uranium confirmed. Rotary-percussion drilling showed the presence of uranium but a subsequent programme of diamond and rotary percussion drilling indicated that the concentration of uranium was uneconomic. Within the tufts and volcanics of the prospect the uranium existed as uranyl phosphates within the oxidized zone. Geological mapping and the diamond drill core showed that the Stag Creek Volcanics are part of the Lower Proterozoic Masson Formation, probably with member status, rather than the expression of an Archaean basement ridge. This change in the interpretation of the fundamental structure of the Pine Creek Geosyncline has led to a reexamination of the stratigraphy and to suggestions which differ from the current concept.

Jan 1, 1977

Cessation of mining on the Bendigo goldfield makes it evident that, as the older generation fades away, knowledge of the famous Bendigo saddle reefs will be limited in the future by their written records. It is important therefore that the summarised account by D. E. Thomas (1953) in the Geology of Australian Ore Deposits should not be misleading. Fig. 6 in this article is stated to portray a cross section and longitudinal section through a series of gold shoots in the Garden Gully 300 ft. reef. The gold shoot along the capof the saddle reef is represented as extending down the east leg in a series of prongs, with the tips of the prongs about 50 ft. apart. It is the purpose of this note to indicate that this illustration can be suspected to be a diagram of the old stopes instead of a diagram of the distribution of gold in the quartz.The original sketches of Figs. 6 and 7 in Thomas' account were extracted, I believe, from the field note books of H. S. Whitelaw, years after his death in the late twenties. Whitelaw was stationed in the Bendigo office of the Geological Survey of Victoria, carrying out geological surveys of the Bendigo mines. He was there for many years before the Gold Research committee started its investigations in 1916 and he was acutely aware of the problem attached to the distribution of gold in the reefs. He had felt concern that manyauriferous reefs were being mined without adequate study and record and he decided, as he expressed it to me, to pick up what he could as he went along. There can be little doubt that the diagrams of Figs. 6 and 7 are products of this resolve.Opportunities to investigate gold occurrences at Bendigo were limited before 1916 because the field was operated by Manuscript received at The Institute 18th November, 1960.

Jan 1, 1961

By J R. Manuel, J M. F Clout

The importance of goethite to Australian iron ore production is steadily increasing as the proportion of goethite-rich, martite-goethite bedded and channel iron deposits increases at the expense of declining production from high-grade microplaty hematite deposits. For this reason, an improved understanding of goethite in iron deposits, its genesis, goethite types and their physical and metallurgical properties is vital to maintaining optimum sintering and blast furnace performance in Asian steel mills.The terminology used to describe goethite in Australian iron deposits is currently highly variable. The discredited mineral name ‘limonite’ is still in widespread use as a field term for goethite and there are many misconceptions concerning goethite chemical grade and downstream physical and metallurgical properties. The goethite classification proposed here is based on geological and physical properties from which three types are recognised including brown goethite, dark brown-black vitreous goethite and highly microporous, friable yellow ochreous goethite.In practice, typical vitreous goethite with highly reflective surfaces and conchoidal fracturing, characteristic of the hard cap zone appears from X-ray fluorescence (XRF) and electron microprobe analysis to be significantly higher in Si (up to 18.7 wt per cent), Al (up to 3.5 wt per cent) and S (up to 0.14 wt per cent) compared to the generally very low (<1 wt per cent for Si and Al) levels of these elements in ochreous goethite and brown goethite. The data dispels the common misconception that friable earthy or yellow ochreous goethite is high in Al and Si and other chemical impurities. However, P was found to be consistently higher (mean of 0.112 wt per cent and up to 0.296 wt per cent) in ochreous goethite than brown goethite (mean of 0.011 wt per cent) or vitreous goethite (mean of 0.031 wt per cent). The highly porous microstructure of ochreous goethite is thought to have a much higher surface area, which may aid in preferential adsorption of P onto the ochreous goethite mineral surface.CITATION:Manuel, J R and Clout, J M F, 2017. Goethite classification, distribution and properties with reference to Australian iron deposits, in Proceedings Iron Ore 2017, pp 567–574 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By J L. Mauk

 Broken Hills is an adularia-sericite epithermal Au-Ag deposit, hosted in flow-banded rhyolites and overlying rhyolitic pyroclastic rocks in the eastern Hauraki Goldfield. The 7.1 Ma deposit was the largest producer of gold in the eastern Hauraki Goldfield, and was one of very few economic deposits hosted in Pliocene rhyolites. This paper presents the results of a recent study in the upper levels of the deposit. Maps and cross-sections constrain structural and lithological relationships, and the lateral and vertical extent of a breccia pipe û the major feature of the upper levels.   Previous studies in the upper levels of Broken Hills have shown that gold and silver values are concentrated around and within a large breccia pipe, mined by a series of æcaveÆ stopes and in veins. Contour diagrams of Au-Ag data from channel samples indicate that the breccia pipe was a major fluid channel-way for mineralising solutions.   The breccia pipe deposits are part of the dynamic geothermal system that formed the Broken Hills ore bodies; they developed as a result of hydrothermal brecciation in areas of structural weakness within a rhyolite pyroclastic unit that overlies a massive rhyolite lava-flow unit. The main breccia pipe begins near the rhyolite/pyroclastic contact, having the shape of an inverted, inclined cone, and consists of silicified breccia, stringers of quartz, and irregular patches of clay-altered country rock. Smaller zones or pockets of hydrothermal eruption breccia are silicified and contain low grade gold in the matrix and in the adjacent silicified wall rocks.   Quartz has been classified according to its physical characteristics as seen in situ and hand specimens indicate that vein definition decreases upwards, perhaps as a result of changing lithological conditions and/or increasing proximity to the paleosurface. Hydrothermal quartz is widespread as veins and as a replacement mineral, or lining fractures and cavities and overgrowing rock fragments. Breccias contain vein quartz, but some quartz veins cross-cut breccias, indicating that vein and breccia formation was relatively synchronous and overlapped in time.   Disseminated gold-silver mineralisation is associated with vein quartz and silicic alteration of the wall rock within the breccia pipe. The auriferous zones are highly irregular and erratic, and sampling results show a wide range of gold-silver ratios, suggesting that highly volatile physiochemical conditions prevailed during mineralisation.

Jan 1, 2005

By J Cornejo, A Pinochet, C Caviedes

The ore extraction rate and the incorporation of new areas are key operational parameters. In massive deposits mined by caving techniques they both control the cave back geometry, which is mostly responsible for the induced stress state around productive levels. Early detection of deviations from admissible geometries will prevent stability problems related to geomechanical hazards, helping to improve safety and working conditions and reduce the potential for lost reserves.This paper describes a mine planning tool currently in use at the El Teniente mine. This tool involves the control of the cave geometry based on rules that have been defined as a result of different studies and experience collected during the operational history of the mine.This mine planning strategy achieves an extractive mining process with lower risk than conventional planning methods, ensuring ore reserves extraction if followed as planned while reducing unexpected changes in mining sequences.CITATION:Cornejo, J, Pinochet, A and Caviedes, C, 2016. Geometric control for strategic mine planning at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J Addai-Mensah, M Adam, W Skinner, J Begelhole, K Quast

Granulation of iron ore fines into robust granules is critical to successful sintering and blast furnace operations in iron and steelmaking. Iron and steelmakers desire iron ore granules with high strength, uniform size distribution and low fuel consumption to enhance efficient sintering operation. Unlike hematite ore, magnetite concentrates do not granulate easily at low binder dosage to yield coarser granules due to the absence of nucleus particles. This motivates the present study to harness the complementary properties of hematite ore to enhance granulation of magnetite concentrates via blending. The current state-of-the-art in hematite and magnetite blend granulation is reviewed, along with granule property limitations. Preliminary experimental work on granulation of hematite and magnetite blends as a precursor to sintering is reported.CITATION:Adam, M, Addai-Mensah, J, Begelhole, J, Quast, K and Skinner, W, 2017. Enhancing magnetite concentrate granulation by blending with hematite ore, in Proceedings Iron Ore 2017, pp 17–24 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Principal component analysis of the variation of Cu, Ni, Zn, Pb, Mn, and Cr in a control group of 96 samples of surface ironstone from the Yilgarn Block, Western Australia, was used to derive a simple graphical method, based on only Cu, Ni, and Cr, for discriminating between massive nickel gossans and other ironstones.When the graph was tested by plotting 400 control samples, it failed to correctly classify only nine out of 176 gossans and 11 out of 224 other ironstones.

Jan 1, 1974

By J Guo, K Williams, J Y. Guo, A W. Roberts, M Jones, B Chen

Numerical simulations using the discrete element method (DEM) were carried out to investigate the flow patterns and stress field redistribution at the hopper and feeder interface. The influences of different filling heights, belt speeds and clearances between the hopper bottom and feeder surface on feeder loads were studied. Meanwhile, experiments were conducted by utilising wedged plane-flow hoppers with different configurations and horizontal feeders with various clearances. The simulation results were compared with theoretical values and experimental measurements. In terms of the cases presented in this study, simulation results reveal good agreements with experimental observations regarding the flow pattern. Being similar to the theoretical values, the simulations provide close predictions on vertical feeder loads for steady flow states, but they may show significant overestimations for initial states. Additionally, suggestions are given for relevant simulation parameters based on the comparisons shown in this investigation.CITATION:Guo, J, Roberts, A W, Williams, K, Jones, M, Chen, B and Guo, Y J, 2017. Simulation investigation of flow patterns and feeder loads at hopper/feeder interface, in Proceedings Iron Ore 2017, pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

In the latter half of 1973 a contract was given to Roberts-Holland Joint Venture for the stripping of the southern exhaust airway.The contract was carried out efficiently and relatively cheaply. It was completed 2 months ahead of schedule.The sinking stage and in particular the drilling jumbo proved to be a success and helped produce an above schedule stripping rate.No major problems were encountered with ground conditions or ventilation. A survey of the shaft showed the diameter to be within the set limits of 5·49 m ± 0·15 m.

Jan 1, 1974

By A G. Mitchell

Stream sediment geochemical analyses were collated from open-file mining company reports and assembled in the REGCHEM computerised database at the Institute of Geological and Nuclear Sciences Limited. The database operates on an IBM-compatible PC microcomputer using an application programmed in dBASE IV and termed GEOEXPL. By August 1992, data for 6383 stream sediment samples from 6335 different sites in the Coromandel Peninsula region (Hauraki Goldfield) were entered, giving a total of 29 292 separate elemental analyses. Preliminary statistical analysis using PROBPLOT on a set of data collected by AMOCO from the Mahakirau-Whangapoua area shows that these data are a complex mix of subpopulations related to mineralisation and different source rock types. Thresholds of 37 ppm copper, 31 ppm lead, 112 ppm zinc, and 2.3 ppm molybdenum, defmed by arithmetic models for the combined data set, separate the individual element sets into 'first order anomalous/lesser anomalous and background' subpopulations as follows: copper five per cent/95 per cent, lead five per cent/95 per cent, zinc one per cent/99 per cent, and molybdenum 15 per cent/85 per cent.

Jan 1, 1992