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By D S Wallis

Northern Australia leads in world-class mineral deposits' is a bold statement. First there must be a starting point. Land north of the Tropic of Capricorn (23¦ 26' 5") will be regarded as Northern Australia covering nearly 40 per cent of the land surface of Australia. As opposed to land south of the Tropic of Capricorn, it should be regarded as Tropical Northern Australia and for the sake of brevity, (TNA) Refer Figure 1. Apart from the tyranny of distance from centres of power and population in the temperate zone, it suffered in the past from the belief that the tropics are unsuited for European workers and from the lack of infrastructure. Outstanding mineral deposits of iron, base metals, gold and diamonds, discovered and developed in the past three decades, provided the substance for the title. There are many world-class mines producing and there are mineral deposits neutralised through Government policy. TNA can maintain its lead in world-class mineral deposits provided Government policy will stop partitioning the land and decreasing that available for exploration. Let's look at what we have that is world-class. In Western TNA iron ore deposits at Paraburdoo, Mt Tom Price, Marandoo, gold at Telfer, diamonds at Argyle. In central TNA uranium at Ranger and Jabiluka, lead-zinc-silver at McArthur River, gold at the Tanami, manganese at Groote Eylandt and bauxite at Gove. In eastern TNA Mt Isa, Hilton, Century zinc-lead, bauxite at Weipa, gold at Kidston, Mt Leyshon, magnesite at Yamba and coal mines in the Bowen Basin. Those mines or deposits stand out yet are only an indication of the numerous lesser mines and of mineral deposits depending for development on market demand and/or changes in Government policy, eg 'The Three Mines' policy. Very large areas of mineral rich structures in the western, central and eastern parts of TNA are concealed below flat lying comparatively young unmineralised sediments. The Great Artisan basin sediments in eastern TNA can and do host oil shale and non metallic minerals. Nearly 40 per cent of western TNA is covered by the Great Sandy Desert. The Canning Track, with a series of 54 wells, was constructed by surveyor Alfred Canning in 1908 - 1910 with great difficulty. It extends 1700 kilometres from Halls Creek in the north to the gold town of Wiluna in the south, through the Great and Little Sandy Deserts. Gold explorers are following favourable structures extending to the north east below the sediments and sand hills covering the track. Half of central TNA's mineral structures are concealed by the Tanami desert and the Cretaceous sediments covering the pastoral regions of the Barkly Tableland and the Daly Waters to Top Springs pastoral areas. The Georgina Basin in the south eastern section is part of the concealment.

Jan 1, 1994

By D Kentwell

For deposits where a full assay suite of elements/oxides is available and where several variables are critical to the evaluation of the deposit, it is desirable for the estimated block values of all elements/oxides to sum to 100 per cent of the weight per cent. This is difficult to achieve in practice and the estimation methods used need to be designed to minimise bias of the key elements/oxides by ensuring that block estimates are consistent with the individual assays and that the estimated totals are as close as possible to 100 per cent.This paper presents a case study of two domains within a magnetite hematite deposit, one with a high level of drilling classified as Measured and one with a lower density of drilling classified as Indicated. Several estimation methods were tested to evaluate their ability to maintain consistency of the proportions of each element/oxide and sum to 100 per cent. The following methods were evaluated: ordinary kriging, co-kriging, inverse distance and min/max autocorrelation factors (MAF) all as implemented in the Geovariances Isatis software.The comparisons showed that the MAF method produced the most robust estimates in terms of block totals and that grades and tonnages at the reporting cut-off were not significantly different between methods. At an individual block scale all methods produce artefacts that are less than desirable but can only be remedied by additional drilling.CITATION:Kentwell, D, 2015. Comparison of min/max autocorrelation factors, kriging, co-kriging and inverse distance block totals – a magnetite hematite case study, in Proceedings Iron Ore 2015, pp 465–474 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The facilities used and techniques employed in the manufacture of steel and iron rolls at the Steel Foundry, B.H.P., Iron & Steel Works, Newcastle are described.

Jan 1, 1972

By Amelunxen R, Finch JA

Flotation columns represent an important addition to flotation practice. Columns have largely replaced. conventional machines in molybdenum cleaning in Canada. Columns have been successfully tested on bulk copper/molybdenum cleaning at Gibraltar Mines Ltd. A rougher cleaner/scavenger cleanercombination was shown to be capable of giving higher grades and recoveries compared with three stages of conventional cleaning. A control strategy for the columns has been developed. An interaction between gas hgldup and wash water rate has been exploited to control performance.

Jan 1, 1985

The use of rubber-tyred equipment in a decline mining system requires that roadways be kept free of running water. At Renison this is achieved by the use of stage pumping or gravitating to a major pump station and pumping from there directly to the surface. The frequent use of pick-up lines and pump boxes in the decline system provides a method of water control and reduces the amount of slimes in pump lines. The Bassett Fault structure, which lies on the hangingwall of the mine is the major source of ground water. This is encountered in diamond drill holes and exploration develop- ment. Dewatering of this structure is possible by controlling the flow from selected holes. Future pumping requirements may be predicted by analysing changes in the level of the water table and by calculating dewatering rates required to maintain ore reserves available for production.

Jan 1, 1977

Coal geology plays an essential role in the investigation of in situ coal seam quality. Coal geology can also play an important part in laboratory studies such as coal washing and coking, and in operating plant problems.

Jan 1, 1976

Problems associated with gas management become more significant as exploitation of coal reserves in the Bowen Basin in Australia becomes deeper. At Oaky North mine, relocation of production from one area of the mine to another with a higher gas content required the use of pre-drainage, post drainage and inertisation techniques to enable production activities to continue largely uninterrupted. Innovative surface to inseam drilling techniques were developed for pre-drainage of reserves close to mine workings and have proven to be largely successful. The gas management techniques adopted and specific experience gained are discussed in this paper.

Jan 1, 2005

By Biswas AK

The solubility of nickel in matte smelt- ing slags, both as oxide and in the metallic form, is predicted using the results of a recent experimental work carried out with lime- free iron silicate slags as well as slags containing lime. Predicted solubilities are much lower than the nickel content of smelting slags, indicating that entrapped and possibly dissolved matte could be the major cause of nickel losses in such slags.

Jan 1, 1975

By M Cooksey, C Goodes, G Wellwood

Light metals have great potential for application in the automotive and aerospace industries because of their excellent physical properties. The usage of aluminium, titanium and magnesium is limited by relatively high costs of production, associated energy costs and large ecological footprint. In the case of aluminium, significant improvement to the Hall-HTroult process is still achievable through advances in cell design, materials and process control. Alternative production processes, including carbothermic reduction and low temperature routes are also possible. Magnesium and titanium production are currently dominated by batch metallothermic processes and new process routes are required to develop these industries. Research at CSIRO, through the Light Metals Flagship, is currently focused on step change improvements in the production of light metals, aimed at lowering energy usage, increasing productivity and reducing the overall environmental impact. In this paper, the overall status of the existing technologies will be described, highlighting areas that are being developed around the world and at CSIRO.

Jan 1, 2006

By A Hewitt

Portland cement is the chief binding ingredient in mine backfill. In the presence of water, the chemical compounds within portland cement hydrate causing hardening and strength gain. During hydration, heat is generated. In certain cases, hydration heat may be produced significantly faster than it can be dissipated, which can create high temperatures in the underground environment. This paper presents the results of a series of investigations aimed at quantifying the heat generated by cemented backfill during hydration. Scaled stope models, instrumented with thermistors, were used in the investigation. Heat transfer to the hanging wall, orebody, footwall and cross-cut and production drifts was assessed during the backfill curing process and relationships between cement content, cure time, and heat generation were developed. The results of this work will assist mine operators in predicting the heat generated by cemented backfill and provide the necessary information to implement effective engineering control of heat in the underground environment.

Jan 1, 2005

The program, WASTRT 70, was set up specifically to handle the design of tunnel liners and underground structures where inter- action between rock and structure significantly affects the design. It may however be used for any mass/R.C. structure capable of being simulated by straight line elements between modes and with loading restricted to nodes. The analysis system adopts typical elastic/stiffness matrix methods. Two main mass/R.C. design segments are utilized (1) Design of section depth based on maximum required stresses and optimum steel/concrete ratios. (2) Design of reinforcement for a given section depth with concrete stresses given for mass and water code structures. Each design segment covers shear, minimum principal stress on ~ , heavy compression as per code (columns), heavy compression one-face steel (tunnel liners), tension and water code requirements for all moment/thrust/section depth ratios on rectangular sections.

Jan 1, 1976

By J M. Palin

Hydrothermal scheelite precipitated in fault-veins at Paradise, Bonnie Jean, Davidson's and Glenorchy mines display chemical variability involving REE patterns that are transitional between two end-member types. Type I is a MREE-enriched pattern with no or a small positive Eu anomaly. Type II is a flat to MREE-depleted pattern with a strong positive Eu anomaly. The chemical inhomogeneity of these scheelites can be explained by a model of fractional precipitation of REE, with preferential removal of MREE from the fluid during precipitation of scheelite. Irrespective of the mechanism responsible for scheelite precipitation, the source of dissolved constituents is different for scheelites from the Paradise Mine. Bonnie Jean, Davidson's and Glenorchy scheelites formed from LREE-enriched fluids whereas Paradise scheelites precipitated from fluids that were lower in LREE. These inferred fluid characteristics cannot be linked unambiguously to specific source rocks in the region, but could suggest that scheelite deposited in the Paradise fault-vein reflects a more mafic source of REE possibly greenschists, whereas the REE in scheelite from the other mines suggest a more felsic source.

Jan 1, 2003

Like almost any other 19th century mining area, the West Coast saw its 20th century scrapping era when machinery which had been installed in seemingly inaccessible places was somehow dragged out again. Fortunately there were some spots so remote that they defied even the most zealous of these pioneering recyclers. One of these was Big River, a mining locality in a rugged landscape straddling the headwaters of the Grey and Inangahua rivers. As a result there remains an internationally important collection of mining equipment including a poppet head, two steam winding engines, a pair of boilers, part of an aerial cableway with its loading system, and remnants of a stamp battery along with its associated gold smelter, cyanide tanks and zinc boxes. There are also assorted building remains associated with 60 years of mining and settlement. Since their abandonment in 1942, these relics have all somehow survived a further half century in a far from favourable climate with two or three metres of rain a year, frequent snowfalls and hot summer temperatures. The rate of decay during the past few years has been alarming.

Jan 1, 1996

By Y Gu

Based on the mode of occurrence, gold is classified into three categories: microscopic gold, submicroscopic gold and surface-bound gold. Microscopic gold, or visible gold, refers to gold minerals in which Au occurs in a substantial amount, such as native gold and electrum. Submicroscopic gold, ie invisible gold, refers to gold contained in the structure of other minerals (mainly sulfides) in minor to trace amounts. Surface gold is the gold that was adsorbed onto the surface of other minerals during mineralisation and subsequent oxidation or metallurgical processing. Gold mineralogy has a significant impact on its extractive metallurgy. Gold process mineralogy helps address problems related to gold ore processing. It is widely used as a predictive and troubleshooting tool in gold ore processing, and provides useful information on process selection, flow sheet development, recovery improvement and reagent consumption optimisation. This paper will begin with the classification of gold ores, and will focus on gold mineralogy and how it impacts extractive metallurgy through case studies.

Jan 1, 2008

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

By Segnit R. E

Two suites of dusts (waste-heat boiler and electrostatic precipitator) collected in 1976 and 1980 from the Kalgoorlie nickel smelter were subjected to chemical and XRD analysis and were examined by SEM and optical microscopy. The spherical to sub-spherical particles contained oxide and glassy phases with small amounts of sulfide. XRD showed that the major phase was a mixed Ni-Fe oxide spinel with some hematite. These phases compared well with those predicted by thermodynamics. The particle size distributions showed that in the 1976 and 1980 suites 20 per cent by weight was respectively coarser than 60 and 115/lm (boiler dusts) and 40 and 30/lm (precipitator dusts). Maximum particle sizes estimated from sedimentation chamber theory were found to be in reasonable agreement with the maximum sizes found in the dusts.

Jan 1, 1984

Two separate mine rehabilitation programmes carried out by Australian Consolidated Industries Limited (A.C.I.) in South Australia at Normanville and Port Lawler are discussed. Emphasis is given to the methods used, the results achieved and to possible future improvements.

Jan 1, 1976

By Wilson AF

Gold-silver mineralization at Cracow and Ukalunda in Queensland comprise quartz-filled veins, fissures and breccia zones hosted by propylitically altered volcanics and epizonal intrusions which are strongly fractured. The terrestrial volcanic facies, structural setting, type of alteration and complex mineralogy suggest these deposits are of the epithermal type.The 180 depleted character of the wall-rocks is consistent with the involvement of meteoric waters in convective hydrothermal cells associated with the vulcanism. The Cracow quartzes have remarkably low 6180 values from -2.0 to -3.4 per mil typical. of meteoric hydrothermal systems at high latitude, consistent with the inferred position of Australia during the Permian. 6180 values for the Ukalunda quartzes exhibit a wide range from 5.1 to 14.9 per mil which reflect the mixing of magmatic and meteoric waters, and a steep geothermal gradient.Further stable isotope and geochemical studies are in progress to establish the scale and morphology of the zones of anomalous 6180 and mineralogy in the wallrocks which constitute significant exploration targets.

Jan 1, 1984

The detailed work done by Stillwell and Edwards on the occurrence of cobaltite and safilorite-Iollingite at the South Mine, followed by its presentation as a paper to the Institute, calls for, a few notes on its occurrence elsewhere in the Broken Hill field. No massive cobaltite similar to that in the South Mine veinlet is known except from the Consols Mine (as mentioned in the paper). Fine grained cobaltite has, however, been found in low-grade ore from the North Mine. Microscopic grains occur in a mineralized green feldspar pegmatite. The feldspar has been replaced in part by graphite, and the cobaltite occurs in association with the graphite. In its hardness, pinkish-white colour, and resistance to the standard etchingqeagents it is similar to the South Mine cobaltite; it is etched by acid permanganate solution. An interesting feature of this occurrence is the way in- which some of the minerals (notably galena) have forced apart the graphite lamellae in crystallizing, forming lenses enclosed by the curved cleavage surlaces 0;[ the graphite.StillwelI and Edwards cite a note by G. Smitht for the statement that "cobaltite has been recorded from the Australian Broken Hill Consols Lode in the vicinity of the rich silver deposits, though not in contact with them."Smith, however, is here referring to the oxidized zone. Elsewhere in the same article he states "... a deposit of cobaltite in a very much altered condition was found. This was impregnated with silver, and assayed as high as 3,000 ounces," Of the cobaltite in the unoxidized zone, Smith simply states that it became rarer with depth.Cobaltite has also been recognized by Mr. H. F. Whitworth, M.SC., Curator of the Mining Museum, Sydney, in specimens from Burt's Copper Mine eight miles south of Broken Hill.

Jan 1, 1944

Gold mineralization like other low concentration high value commodities has gained the notoriety of being difficult to sample. This adversely affects the confidence that can be placed in resource estimates and ore reserves. As an example, it is not uncommon to find differences of the order of 30% between duplicates of a single sample sent to two different commercial laborartories. Two halves of drill core generally show marked differences in grade. Again differences of 50% are not uncommon in halved core. In the context of this type of "error" within the base data used for the resource estimate, many of the subtleties of computation methods and expert judgement of resource categories, are almost a case of shutting the gate after the horse has bolted. Managers, financiers and consultants must question the quality of the base data upon which resource estimates are made. They must insist that standard and duplicate samples are used to measure the accuracy and precision of commercial analytical laboratories, that sampling practices have been checked for possible bias and give tolerable repeatability. Further they must ensure there can be a realistic confidence in the estimates by correctly using these measures of data quality to quantify risk.

Jan 1, 1990