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By Tiu C, Sarmiento G, Uhlherr PHT

Fundamental rheological properties of slowly settling mineral slurries are reviewed. Slurry flow is discussed in terms of observed shear stress-shear rate behaviour. Particular emphasis is placed on establishing procedures for scale-up and design. Flow property measure- ments on red mud, a waste product from the Bayer alumina process, are presented and used to illustrate recommended design procedures.

Jan 1, 1978

Two main aspects need to be considered when analysing a potential petroleum development project. Firstly, an estimate of the recoverable reserves must be made, and in many instances, these reserves must serve as collateral to finance development if outside capital is required. Secondly, the likely production profile and cash flow has to be established, and this cash flow then must meet debt service require- ments and in addition generate the required profits. In making these crucial deter- minations, the impact on the project of a wide variety of risks has to be analysed. A computer model, which represents the project in its entirety, is a great aid in determining project viability. Such a model requires imput from geologists, engineers and economists, and interpretation of the model must also be a joint effort. Communications, and inter react ion amongst individuals and disciplines is essential if the best answers are to be obtained

Jan 1, 1983

As a result of high fuel prices and substantial haul distances or vertical lift from pits, the development of large inpit crushing and conveying systems at many open pit operations has occurred over the last decade.The basic criteria that has to be met is that the material is reduced in size to be conveyable. Generally this requires a top size of less than 300 mm.

Jan 1, 1992

A study of the effect of nickel on the cupellation process has shown that a very low "nickel limit" must be imposed for cupellation (0·08 grams nickel or 0·05 grams when copper is present). In the presence of slightly greater amounts of nickel, lead tends to spreadon the cupel with detachment of drops from the main lead pool. In crucible fusions nickel contaminates the lead button to a small extent, and this contamination is increased.in the presence of either iron or copper. Nickel also causes "shotting" of the lead, this effect being more apparent in the presence of iron.Both the spreading during cupellation and the shotting during crucible fusion are considered to be caused by adsorption of insoluble NiO at the Pb-PbO interface, lowering the interfacial tension.Excess litharge crucible charges are' fused at 116boC. to eliminate shotting. A brief· soaking in molten basic litharge slag effectively reduces the nickel content of lead buttons. The solubility of silver in litharge slags is considerably decreased in the presence of nickel. Corrections can be applied for silver losses in slags but these corrections are not as accurate as with copper ores.INTRODUCTIONThis paper on the effects of nickel on fire assays for silver is the second of an intended series describing investigations into the fire assaying method.In the first paper, discussing the effect of copper on fire assaying processes (Guerin, 1957), it was shown that certain elements, because of their relatively low affinities for oxygen, will tend to contaminate the lead button during crucible fusion and scorification. Nickel, having a slightly greater affinity for oxygen than has lead, would be expected to be oxidized and slagged readily, and would not be expected to appear in the metal phase (lead button) to any appreciable extent. Thus, judged solely on this basis of...

Jan 1, 1960

A resume covering currently accepted views on blasting vibration measurement, human response, and criteria for damage is presented as background information for readers who are not conversant with blasting vibrations. This is followed by sections on vibration level estimation and blasting techniques to control vibration. Emphasis is placed on making use of the scatter in the delay intervals of half-second delay detonators, the use of smaller explosive charges for early delay numbers, and the non- use of zero-delay (instantaneous) detonators in cer`a. n cases.

Jan 1, 1976

This opportunity to present a few thoughts on the question of professional education and training comes at a most appropriate time. In Britain, a great deal of energy is being expended in this, so-called, post-Finniston era, to create a new look for the status of engineers and engineering by the Engineering Council. Naturally, the tune and the tempo are being called by the big institutions which essentially serve the manufacturing industries. However, the Engineering Council in Great Britain also includes the mining and processing institutions such as the Institution of Mining and Metallurgy (IMM) and so there is a chance - if it is taken - for us to contribute to the debate and the determinations that emanate from it. The IMM, of course, caters for the professional status of those engaged in the mining and minerals industries and includes many who do not see themselves as engineers. Nevertheless, the debate is important to these other groups whose livelihood is inextricably bound up with those who are engineers and there are many facets of the engineering policies being shaped that will, I am sure, eventually be enshrined in the requirements for professional status across all the various disciplines in our industry.

Jan 1, 1986

By C Ward, U Mueller

Compositional geostatistics is an approach developed to ensure that the constant sum constraint induced by geochemical iron ore analysis is respected in estimation and simulation. Jack-knifing and cross-validation were used within this framework to compare the results from ordinary cokriging of the additive log ratio (alr) variables with those from conventional ordinary cokriging. Two methods were used to back-transform the alr estimates: the crude additive generalised logistic back transformation and numerical integration via Gauss-Hermite quadrature. Previous work on a blasthole data set from a Yilgarn iron ore mine showed promising results, with the Gauss-Hermite quadrature method returning results comparable to ordinary cokriging from the point of view of bias, but superior in that the constant sum constraint imposed by geochemistry of the data was honoured. Other practitioners have noted that the linear interpolation of non-linear log ratio transformations will result in biased results, and that this bias can be masked in a (grade control) setting where the spatial density is high. To test this assertion, the methodology has been extended to successively lower spatial density data sets. The results and applicability to routine iron estimation are discussed.CITATION:Ward, C and Mueller, U, 2013. Compositions, log ratios and bias - from grade control to resource definition, in Proceedings Iron Ore 2013 , pp 313-320 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

During the past eight years a vigorous drilling campaign resulted in large increases in the reserves of both copper and silver-lead-zinc ores.As a result the Company initiated an increased production programme.Some major capital works have been completed, others are in progress and more are needed to achieve the proposed daily throughput of 14,400 tons. The increased ore potential justified a copper refinery which has been constructed at Townsville. The increased production rate achieved to date, combined with improved techniques and greater mechanization, is assisting the Company to combat the general inflationary trends caused by increased costs for labour and materials.INTRODUCTION"Today we are armed with better weapons in our fight for lowered costs and greater efficiency, but we must not flag in our efforts to improve." Such was the resolution expressed by Mr. K. B. Gross, then General Manager of the Company, in his review lecture delivered to the First Ordinary Meeting of The Australasian Institute of Mining and Metallurgy at Mount Isa on 18th August, 1952. This present review of the period 1952 to 1960 records our efforts to fulfil this resolution. At the th:ne of Mr. Gross's statement,copper production was commencing in earnest. Although the importance of Mount Isa's copper orebodies was well recognized, the major discoveries which led to Mount Isa's emergence as Australia's premier copper mining and smelting operation were not known. These ore discoveries and their subsequent development are the major factors which warrant a further review of the Company's progress.The increased magnitude of the Company's operations is illustrated on graphs of Tons of Ore Treated (Fig. 1), Metals in Products (Fig. 2), Water Consumption (Fig. 3)...

Jan 1, 1961

By L McCarthy, B W. Cuffley, O K. Thomas an

The Central Victorian Goldfield is a world-class field located in Victoria, Australia. It is currently undergoing a revival through activities in the Bendigo, Ballarat, Tarnagulla, Maldon, Castlemaine and other fields. Sediment-hosted auriferous gold-quartz reefs that are structurally and geometrically complex dominate the region. To date, no remote methods have been developed to assist in the targeting of the discrete high-grade oreshoots that characterise the mineralisation. An understanding of the structural setting and controls, and thus likely frequency of repetition of oreshoots remains the main exploration tool. Gold within the reefs is generally characterised by both its coarse nature (>100 up to 10 000 microns) and erratic distribution; as a result, most of the Victorian deposits are classed as high- to extreme-nugget effect systems. This characteristic ensures that mineralisation is very challenging to explore, evaluate and exploit. The key issues facing the explorer and miner are related to effective sampling, and definition of geological and grade continuity, and ultimately grade and tonnage. Tonnage can often be estimated to a reasonable level of confidence, whereas the grade estimate generally carries a medium- to high-level of uncertainty. In these deposits, surface diamond drilling alone is generally only able to define an Inferred Mineral Resource, with underground development, closely spaced in-fill drilling and bulk sampling/trial mining required to define Ore Reserves. The extraction of gold from ores is relatively simple, based on the coarse nature and hence amenability to gravity recovery. Ground conditions and the need for in-stope grade control (eg mapping, sampling etc), generally point toward mechanised cut-and-fill as the primary stoping method in the region. To potential investors this style of mineralisation has been viewed as high risk, because of the associated low confidence in the grade estimate, general paucity of Ore Reserves at mining start-up and need for underground development at the Feasibility Stage.

Jan 1, 2004

SOME notes on the works of the Electrolytic Refining and Smelting Company of Australia will no doubt be of interest to members of the Institute, more especially as much of the work is new to Australasia.As many of the members who may read this paper have not been in a position to visit works of this kind, and are consequently not thoroughly acquainted with all the operations carried on, the author has taken the liberty, in some cases, to enter into explanation which would otherwise be unnecessary.The works are situated at Port Kembla (New SouthWales), about fifty miles south of Sydney, and are approachable both by rail and water. The Government has recently built a low-level jetty upwards of five hundred feet long, and intends installing at an early date an electrically operated portable crane to facilitate the handling of material to and from the boats. Thi.s will mean a considerable reduction in the length of time that boats are laid up at the jetty. There are also under construction two breakwaters, which, when complete, will materially assist shipping operations. The works as they exist are capable of turning out 1200 long tons of refined copper per month. It is gratifying here to note the unqualified success with whichthe E.S.A. refined copper met with on first being put on the market.

Jan 1, 1911

By McKenzie C. K

During a programme of explosive performance evaluation at Hamersley Iron, Mount Tom Price Mining Operations, the relative performances of a range of heavy ANFO explosives were compared during normal production blasting operations. In addition, a number of heavily instrumented single hole blasting trials were conducted with each product type. The blasts were monitored in terms of blasthole velocity of detonation (VOD), measured using multi-point plasma conductivity probes with up to 16 measurements per blasthole. Up to 16 blastholes were monitored in each production blast. The results of measurements show a marked difference in performance of all heavy ANFO products between single blastholes and full production blasts, indicating a significant degree of interaction between blastholes in production blasting. The interaction is shown to result in a loss of detonation pressure of explosive, and considered to lead to a loss of fragmentation. The degree of interaction is seen to increase with increasing emulsion content in the products, and is more pronounced in some explosive types than others. The paper presents the methods of measurement and analysis, and the results of monitoring, together with implications on blast design and application of heavy ANFO products.

Jan 1, 1990

By J J. Wilkinson, C J. Ha, R J. Herrington

The Pic de Fon iron oxide deposit is a potential major new source of iron ore, located at the southern end of the Simandou range in eastern Guinea on the West African Craton. The deposit is hosted by banded iron formations (BIFs) within a supracrustal sequence, which lies unconformably upon a crystalline basement. The host BIFs and shales have been metamorphosed up to staurolite-grade itabirite and phyllite respectively. Stratigraphic relationships are obscured by polyphase deformation, although the sequence appears to comprise a lower phyllite(-minor quartzite) unit and transitional phyllite-iron formation overlain by three itabirite units. It is the itabirite units, selectively enriched to iron grades in excess of 65 per cent Fe (with low deleterious elements), that constitute the Pic de Fon deposit. Samples acquired from exploration diamond drill holes and outcrop across the deposit have been collected to investigate the Pic de Fon lithologies and iron-rich material types. Initial research techniques have included geological mapping, reflected light microscopy, x-ray diffraction (XRD) studies and ICP-AES geochemistry. The aim is to develop a model for deposit genesis that may assist future exploration and deposit exploitation planning. Results to date have identified a variety of hematite textures, which include recrystallised trellis, interlobate and granoblastic hematite after magnetite. In addition, fine-grained bladed to acicular microplaty hematite appears to both replace itabirite banding and infill porosity. Field relationships indicate a structural control of microplaty hematite development. Geochemistry and XRD results suggest a loss of silica with negligible iron addition during the conversion of itabirite to ore grade mineralisation. The enrichment process(es) is also accompanied by a gradual increase in K, Mg, Na, (Ca and Al).

Jan 1, 2005

By Hughson B

The need to prevent the sterilisation of coal stems directly from the fact that it is a non-renewable resource. In N.S.W. a vast amount of coal resource is located under major public utilities such as freeways, railways, stored waters, pipelines carrying gas, water and sewage, and transmission lines. Total extraction has occurred under freeways, transmission lines and pipelines with little or no damage. Where damage has resulted, the cost of restoration was only a small fraction of the value of the coal recovered. However, coal at present is being sterilised and perhaps lost for ever under stored waters and railways. If engineering solutions are available for mining under these improvements economically and with maximum safety, then coal should be extracted and utilised to the benefit of the State.

Jan 1, 1986

By G Kuntz, V Wall, B New

The prime aim of the Campbell Mine project was to develop a 3D geological model for the Campbell-Red Lake system to contribute to an exploration model for the region. The base data is composed of over 60 years of geological data covering an area of 16 by 8 km, and from surface down to 1830 m depth. This paper concentrates on the methods used in the GeoSpace system for the processing, integration, display and interpretation of such a large and diverse data set. A block model was developed that recorded the relative frequency of each geological feature within each block. The data input for the block models were based on recoding of the Campbell Mine drilling and channel sample databases into lithological, alteration and structural subsets. The value for each geological characteristic inserted into each block is calculated from all available data that falls within the block. Relative and absolute comparisons of the individual variables provide a targeted outcome from which the blocks are coloured for visual inspection. Different combinations of variable comparisons can be evaluated so that required features are highlighted for interpretation. Blocks are displayed to illuminate the ædominantÆ rock type, according to a formula that may be varied interactively to display the features required by the geologist. This flexibility allows rapid remodelling of lithological distributions, commonly highlighting minor lithological packages not readily visualised in, and interpreted from, drillhole traces alone. The 3D geological model was built from the drillhole datasets and old mine plans utilising standard 3D mining, GIS and database software, with several iterations of plan and sectional interpretation. Near surface bedrock geological interpretations were further constrained by low level aeromagnetic data. The Geospace approach employs an innovative technique for visualisation of the distribution of lithological packages and alteration via block modelling. The method utilises the block model format of data handling as it is considered to be more visible than drilling, flexible enough to incorporate a wide range of data sources, and allows for spatial proximity relationships to be investigated. The method is a simple form of processing large data sets so that results are clearly visible. The calculation is much more rapid than estimation procedures, and does not have any requirement for geostatistical interpretation which is also time consuming. Geospace is not unique to any mine environment software and it is expected to be able to be performed in any system. The proper portrayal of the internal structure of the mineralised body will provide practical input to exploration and mining principally in the areas of resource estimation, exploration vectoring and ore/waste characterisation and may be incorporated with other data to include mine support and mine scheduling.

Jan 1, 2003

Discovered in 1896, the Sons of Gwalia orebody is located in a ductile mylonite zone within a sequence of Archaean pillow metabasalts and minor metasediments of greenschist facies which are variably sheared.The ore zone has good continuity, being 110 m wide and 500 m long, dipping 45 degrees east and plunging 70 degrees to the south to a depth of 1500 m downplunge. A strongly-developed foliation is present together with a prominent lineation paralleling the plunge. The mylonite zone consists of unmineralised chlorite schist and a 'U' shaped mineralised zone of chlorite-sericite schist with varying amounts of quartz-carbonate as veins parallel to foliation, boudins, and locally as massive quartz-carbonate. Pyrite is the dominant sulphide present.Grade control utilises RC holes on a 10 m x 10 m pattern, with infill blast rig holes 5 m deep where necessary.Some visual control of ore boundaries is present and, combined with good ore continuity and a knowledge of the structure of the orebody, enables cost-effective grade control to be achieved. To-date, over three million ounces of gold have been produced from the orebody.

Jan 1, 1993

This paper outlines the mechanism of Stress Corrosion Cracking (SCC) and how it can cause premature failure of rock bolts. SCC occurs due to the progressive development and growth of cracks in the surface of a metal, and it is caused by the combined effects of stress and a corrosive environment affecting susceptible metals and alloys. It can occur in most metals including stainless steel. It is not a new phenomenon, but its effect on rock bolts has only been recognised recently.Rock bolt failures caused by SCC appear to be brittle failures which occur at less than the ultimate tensile strength of the bolt. In the mining industry, SCC failures of rock bolts can occur a few months, or after many years of exposure to stress and a corrosive environment. If SCC of rock bolts is suspected, then the rock bolts should be examined by a metallurgist, and steps should be taken to reduce the problem.

Jan 1, 1998

By H Catchpole, L FontbotT, J PTrez, M Ageneau, A Bendez·

In the world-class mining district of Morococha, epithermal polymetallic replacement bodies and veins overprint porphyry mineralisation and skarns related to subvolcanic intrusions of Miocene age, thus indicating ore formation in two different environments, separated in time or forming a continuum. The district covers an area of about 70 km2 in the north-western part of the Domo de Yauli complex in theWestern Cordillera of central Peru and is part of the Miocene polymetallic belt, also hosting the deposits of Colquijirca (Bendez· et al, 2008b) and Cerro de Pasco (Baumgartner, FontbotT and Vennemann, 2008). Multiple late-Miocene porphyry stocks intruded Permian, Triassic-Jurassic and late-Cretaceous sedimentary carbonate and volcano-sedimentary formations, as well as large mid-Miocene barren intrusions. Extensive field work and detailedmapping of different styles of orebodies suggest that ore formation in the area was related to the late-Miocene magmatism. Good outcrop conditions and superimposing of different mineralisation styles make Morococha an ideal location for studying ore-forming processes in a complex porphyry-related magmatic-hydrothermal system in which porphyry-to-epithermal transition occurred. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By D Craw

Quaternary warping and uplift of antiformal schist ranges in Central Otago, New Zealand, has resulted in recycling of alluvial gold from widespread, generally weakly auriferous, Miocene fluvial gravels that unconformably overlie the schist, into aprons of fan sediments along the range margins. Basement erosion during uplift has been limited and so gold input from sparse gold-bearing quartz veins in the schist has been relatively minor. In an eluvial cycle on the slopes of the ranges, chemical remobilization of gold occurs during oxidation and erosion of the Miocene sediments. The typically fine-grained (300 - 400 ¦m) gold undergoes chemical modification and grain size enhancement of up to two orders of magnitude, and much of it is redeposited in a large number of relatively small alluvial fans along the range margins. Groundwater mobility within the fans results in minor additional gold mobility and grain size enhancement. During range uplift, a small number of relatively large axial streams and rivers have developed in structural lows between growing antiformal folds. Axial streams 'gather' their flow from consequent streams draining the folds, and flow parallel to a range axis for some distance before cutting across it in an antecedent gorge. The axial streams rework alluvial fan sediments along the range margins, and transport mainly fine-grained gold from the fans along the ranges. This gold is redeposited where the axial streams emerge from a range in the neighbouring structural basin. Axial streams drain relatively large areas of range surface, and thus reconcentrate significant quantities of gold in a small number of relatively large fans and fluvial deposits. The processes of gold collection and re-deposition by axial streams are essentially the same, regardless of stream size. Coarse-grained gold produced by chemical remobilization, is more difficult to transport in fluvial systems, and thus remains in close proximity to eluvial environment where it was formed.

Jan 1, 1995

The Australian industrial relations system is in a state of constant change. We are undergoing a transformation from a compulsory arbitration and an award based system to one which is fundamentally rooted in the concepts of enterprise bargaining. This is true both at the State and Federal level. The structural changes which facilitate the movement away from the predominance of Awards to enterprise agreements has been fostered by both sides of the political spectrum and is a cornerstone of their respective industrial relations platforms.In determining what form or combination of forms of industrial instrument(s) should apply to the individual enterprise, employers must have regard to the viability and sustainability of each form in the changing industrial climate. In particular employers should have regard to the needs and agendas of their employees and unions which may purport to represent Them.

Jan 1, 1998

MOUNT STEWART is situated half a mile south of Leadville railway station, which is distant 240 miles by rail from Sydney via Mudgee. It forms a low ridge from which rock waste and alluvium slope gradually to the black-soil flats of the Coolaburragundy River. The Mt. Stewart mine comprises:(a) The Mt. Stewart workings in M.L. 44, parish Talbragar, Co. Bligh.(b) The Grosvenor workings in M.Ls. 44 and 45, parish Talbragar, Co. Bligh.(c) The Extended workings in M.L. 44, parish Talbragar, Co. Bligh.The workings contain 1375 ft.. of vertical shafts, 1105 ft. of underlay shafts, 800 ft. of rises and winzes, 8520 ft. of drives and crosscuts, and 18,000 ft. of stapes.The mine was first opened in 1888 as a silver-lead mine, and a waterjacketed furnace was erected during 18B2. The furnace was installed with two internally-fired tubular boilers of 35 h.p. and 25 h.p. respectively, and two Baker's rotary pressure blowers. The results of the smelting campaign indicate that, during 14 months, a total of 15,000 tons of ore were treated, yielding silver and lead. In addition to this, a quantity of matte was sold containing about 8000 oz. of silver. As a result of the treatment...

Jan 1, 1925