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By Mayfield P. L J, Honeyands T. A

BHP's two million tonne per annum nominal capacity Hot Briquetted Iron (HBI) plant at Port Hedland in the Pilbara region of Western Australia is based on FINMET¦¦ direct reduction technology. The FINMET¦¦ process produces direct reduced iron (DRI) by reacting fine iron ore with reformed natural gas in a series of fluid bed reactors and then hot briquetting this DRI into dense, high quality iron briquettes. The Port Hedland HBI project represents a major investment in the chemical processing of Australian minerals to higher value products prior to export to Asian markets. This paper describes the FINMET" process and technical aspects of the high-quality HBI product, and provides an update of the current status of the project.

Jan 1, 1999

Size Separation Pretreatment and Alumina Recovery from Bayer Red Mud

Sep 13, 2010

Kalgoorlie is the main mining centre of the Western Australian Goldfields. Its famous Golden Mile' has been noted for the exceptional width and richness of its goldtelluride lodes. Since the mid-1890s production on the major mines has been maintained practically continuously.Rich ore, though not as plentiful or as rich as formerly, is still (1948) being mined in places. Unexplored areas still remain within the main auriferous belt which offer reasonable chances of success with intensive exploration.Much detailed information has accumulated in recent years through the geological mapping of underground workings by some of the larger mining companies. The purpose of this paper is to correlate observations made in most of the accessible old and recent workings in the mines of the Lake View and Star group and elsewhere.GENERAL GEOLOGYRock TypesThe rock formations are:-1. Fine-grained (older) greenstones, locally referred to as calc schists. There were originally pillow lavas and other flow rocks of basic composition, now extensively chloritised and/or carbonated. Pillows and fragmental flow- tops are recognisable. Intercalated with flows near the top of the series are several beds of sediments.2. Graphitic slates and other more arenaceous sediments.Although referred to as slates, they are rarely more than well-bedded shales with poorly developed fracture cleavage:Thick bands of felsitic rock are found in places.

Jan 1, 1952

The sphere of operations of dry crushing has been so much enlarged of late years that the following notes with reference to its advantages and limitations, and also some practical results in connection with the crushing of gold ores will probably be of service to the members of the Institute. Until recently, with one notable exception that of the Mt. Morgan Gold Mine, dry crushing has only been practiced to a very limited extent in Australasia, and elsewhere it might be said to belong to industries other than mining Its sphere of usefulness depends on the fact that the' product is delivered in a dry state without the separation of the finer particles from the coarser to any appreciable extent, thus enabling the following advantages to be achieved with different ores.

The proposed classification scheme is based on two primary parameters, one for petrographic composition and the other for rank, both being determined with microscopic techniques. The scheme has been applied to a wide range of Australian coals and found to provide a useful means of relating their inherent properties to properties such as volatile-matter yield, crucible swelling number, and calorific value, which will determine how these coals might be used commercially.

Jan 1, 1970

The methods and equipment developed and used at the Mount Isa mine to obtain samples of uncemented hydraulic fill lying above major horizontal pillars are described. From existing underground development, samples were obtained at distances up to 50 m, of which up to 30 m was through hard rock. Samples were used to predict fill behaviour as it affected mining security during recovery of the pillars.Specialized equipment for difficult sampling situations and also other sampling exercises are described.

Jan 1, 1976

By R F. G Phelps, C J. S Sangster, G S. C

Narrow vein metalliferous mining in the UK has a long history, but there are only two small gold operations at present (Clogau and Gwynfynydd). Four further gold properties are at various stages of evaluation (Calliachar, Cononish, Curraghinalt and Maestryfer). The South Crofty tin mine closed earlier in the year. Narrow veins are exploited underground and are challenging to evaluate because of their geologically variable nature. They are generally less than 3 m wide, discordant, of variable dip (

Jan 1, 1998

In late 1989, first-pass reconnaissance exploration delineated a 4km x 6km geochem- ically anomalous area centred 10km WNW of Kainantu in the Eastern Highlands Province at 6¦13'S and 145047'E. The area, named the Basangka prospect, lies between 2 200 and 2 400m asl. Interest in the area was prompted by a 14ppm Au assay of a silica-pyrite breccia float sample taken near Henkai village. The prospect was defined after several acid-leached silica- pyrite breccia and comb textured quartz float samples returned assays above lppm Au and relatively high Ag. Very encouraging and anomalous Au values were obtained from panned concentrates, despite the absence of visible Au colours. Several pan concentrates returned greater than 1mg Au and it is believed that the Au occurs as inclusions within iron oxides which were originally pyrite. In this early stage of prospect exploration, any Au value above 0.lppm in- 150# fraction stream sediments is treated as anomalous. Rock chips, panned concentrates and -150# fraction geochemistry all vividly define the areas of interest at Basangka.

Jan 1, 1991

By K Ehrig

You are a geologist, geometallurgist, or metallurgist/process engineer and are fortunate enough to work for an organisation who asks you to design/execute a geometallurgy program. What seems like a simple request is actually not a trivial exercise. æRecipeÆ style manuals are not readily available. However, many æexpertsÆ are lurking around willing to deliver solutions which will solve all of your problems. Even though similar ore deposit styles (e.g. porphyry Cu, IOCG, Ni-laterites, calcrete hosted U, etc.) have many similar characteristics, each ore deposit is unique. Hence your geometallurgy program needs to be æfit-for-purposeÆ. This paper offers some insights gained via designing and executing geometallurgy programs from exploration through to production, and working at a mine where you are held accountable for your metallurgical performance predictors.CITATION:Ehrig, K, 2013. Geometallurgy - What do you really need to know from exploration through to production?, in Proceedings MetPlant 2013 , pp 28-33 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Ore samples generally require preparation before analysis. Serious problems can occur with contamination degradation and particle size effects. Both grinding element contammation and sample cross contamination havebeen bound to be related to sample hardness and operator technique. For best results with minerals relevant to the steel industry, the use of Siebtechnik-type mills required a combination of careful planning, short grinding periods and intermediate sieving of the sample. The results may be extended to most mineral, rock, and refractory sample preparabons.

Jan 1, 1978

Mineralogical analysis of a nickeliferous laterite from the Rockhampton region shows that the nickel is largely associated with the manganese wad and opaline silica. The laterite also contains an appreciable chromite content (about 12 per cent Cr2O,) although this tends to be poorly liberated.Leaching with hydrochloric or sulphuric acid, at atmospheric pressure at the boiling point is non-selective with respect to iron dissolution.The degree of dissolution increases as the acid concentration and retention time are increased; cobalt dissolution requires less aggressive conditions than does the dissolution of an equivalent amount of nickel.Leaching with sulphuric acid at elevated temperatures and pressures leads to a minimum amount of iron dissolution, is rapid, and requires a reduced acid addition rate. Nickel and cobalt recovery from the clarified leachate would be simplified because of the leach selectivity.Pressure leaching appears to be the most practical route for treating the Rockhampton laterite. The economics of processing would be made more attractive by the recovery of a chromium concentrate from the leach residue. This would typically contain about 45 per cent Cr2O, and could be used as a source of chromium chemicals.

Jan 1, 1986

A study of literature on the epidiorite dykes which transgress the Broken Hill lode and its wall rocks reveals a considerable diversity of thought regarding the time of emplacement of such dykes. In this paper it is deduced that the epidiorite dykes were formed at a late stage and were probably post-ore. Detailed mapping, sampling, and correlation of data from over 100 exposures substantiates this deduction. Physical disruption of the epidiorite dykes is indicated and some interaction of the epidiorite and ore at the time of intrusion is inferred.Further petrological study may confirm this.

Jan 1, 1968

The Broken Hill orebody ,occurs in the Willyama Complex, a block of Precambrian rocks which have been strongly folded and metamorphosed at moderate to high grade. Although -the origin of the silver-lead-zinc mineralization remains obscure, recent investigations have substantiated the view that the orebody has undergone concomitant high grade metamorphism with the enclosing wallrocks. The mesoscopic structures produced by this metamorphism are described, and the possible processes Telating to their formation are disoussed.In the high grade ore, metamorphic structures which can be recognized are foliation and lineation, wallrock fragments, layering, flow folds, ore breccias, and sulphide bearing veins. These structures can be related to processes involving plastic flow and fluid phase transport of the mineral assemblage. 'In areas of low grade mineralization adjacent to high grade ore, the structures more closely resemble those produced in -the wallrocks-foliatlon, lineation, layering, folds, and sulphide injections. Within areas of high grade ore, lenses and pods of manganese silicates Probably represent original inhomogeneities in the ore, i.e., portions of manganese-rich and sulphide deficient rock which have been metamorphosed to manganese silicates.From the structures displayed, a sequence of events has been established for the plastic flow of ore during deformation.

Jan 1, 1975

It is shown that factors associated with conditions whIch are thermodynamically favourable for the formation of CuS04 in roasting lead to high copper recoveries on leaching. One of these factors is the ratio of the air to solids used for roasting. This can be varied widely without loss of temperature control in the sulphating roasting of many Australian copper concentrates.Thus, the prediction of the air to solids ratio corresponding to a maximum p(SO3) value, for a given concentrate and temperature, is of importance in fluidized bed roasting, since this could be associated with the formation of a maximum quantity of CuS04. Calculations are presented which predict this air to solids ratio, not only for a given concentrate composition, temperature, and pressure, but also for air which is enriched with sulphur dioxide or oxygen.

Jan 1, 1968

By Miller F. S

The famous Golden Mile of Kalgoorlie in Western Australia was, between 1888 and 19ft, one of the richest and most important gold camps in the world. Annual production, which reached a peak of nearly 1,300,000 oz. in 1903, however dropped to below 400,000 oz. after 1920.Depression seized the camp, and many mines closed down. The output from this old field is now steadily mounting under the stimulus. of a higher price for gold. In 1935 300,000 oz. of precious metal were recovered and the future is bright. Total production from the field is 21,400,000 oz., whereas something like £23,600,000 have been paid in dividends.The Golden Mile has been studied by many geologists. Their somewhat diverse findings were published for the most part in the Australian technical press which, unfortunately, is not sufficiently represented in foreign libraries.The following article is based on an eighteen months' study in the district for Gold Mines of Kalgoorlie Ltd., preceded by four years' experience with almost identical rock types in the, Porcupine district of Ontario. The excellent record of observed fact left by previous invesigators, augmented by talks with observant mining men...

Jan 1, 1937

By C Moorhead

The classification of Mineral Resource estimates for reporting in accordance with the JORC Code is a statement of the Competent PersonÆs confidence in the estimate and an attempt to convey that confidence to the various users of the resource estimate. In general the classification process is either largely subjective, relying on the Competent PersonÆs experience, or relies on statistical measures derived from the estimation process. These statistical measures may not necessarily relate to the overall confidence in the resource which must also take account of the confidence in the geological inputs to the estimation. Several authors, including Jackson et al (2003) and Dominy, Noppe and Annels (2004), have addressed methods of including consideration of geological data and its reliability into the classification process. Henry and Parker (2005) have discussed a quantitative measure for classification of Measured and Indicated Resources related to mine production parcels. These methods rely on the availability of sufficient information for the application of geostatistics, data evaluation techniques or repeated interpretation of data to provide an indication of confidence. They are suitable for very advanced projects. In 2005, using a modification of the financial audit æcontrol and quality criteriaÆ principles, then widely accepted within Newcrest Mining Limited (Newcrest), the principal author developed a scheme which categorised the classified resources into æcontrolÆ and æqualityÆ (or risk) categories. Control covers all aspects of the data collection, the geological interpretation, the data analysis and the modelling of tonnage and grade; it is also influenced by the documentation of the estimate. The quality criteria are a subjective measure of risk associated with the estimation of the resource and refer to the risk that the tonnage and grade are not realised and the consequences if decisions are made on the basis of these estimates. By evaluating the generally accepted level of risk attributed to these quality ratings by Competent Persons within Newcrest, a graphical representation of the confidence in the resource ounces was prepared for communication of the expected confidence in the resource statement.

Jan 1, 2009

The literature pertaining to the electrochemical reaction at the anode during electrolytic reduction of alumina by the Hall-Heroult process is not in universal llgreement about the gaseous product. The possibility of electrochemical formation of CO at the anode was examined using existing data. Although the thermochemistry favours co-evolution of CO and CO2 with CO as the major product, the mechanism of the reaction shows this is unlikely. Since the origin of CO can be more logically explained by non-electrochemical mechanisims, it is concluded that CO2 is the only product from the electrolytic reaction at all current densities.

Jan 1, 1967

By Warren L. J

The effectiveness of shear-flocculation as a method for upgrading simple mixtures of ultrafine (1-11 \lm) scheelite and garnet was evaluated. Statistical methods were used in the design and analysis of the main test program.The stirrer speed, stirring time, and initial weight ratio were all found to have significant effects on both the recovery and grade of the floes produced. The particle sizes also had an effect on the final grade. There were several important interactions between factors which also affected the results. Optimum conditions for shear-flocculation were established, and under these conditions about 80 per cent of the scheelite could be recovered at a grade which depended on the composition of the starting mixture. Starting with mixtures containing 10 and 50 per cent scheelite, the best final grades were between 20 and 50 per cent and between 70 and 90 per cent respectively, the actual value depending on the particular combination of particle sizes.

Jan 1, 1977

Advances in Coarse Particle Recovery - Fluidised-Bed Flotation

Sep 13, 2010

The presence of gold or tin in a particular place in payable quantities may be suspected from geological and prospE;cting reports. It behoves the engineer by judiciously spaced boreholes or pits to establish whether the place is exploitable with profit, and it is the purpose of this paper to set out the ways in which this is done. The various types of deposit to be considered occur in Malaya, Thafland and Borneo, in which countries the writer spent four years in estimating alluvials.The methods described were used in actual practice both by the writer and previous engineers for the same company. The subsequent exploitation of the alluvials evaluated by the methods given below shows that the recovery was as good as, and sometimes higher than, expected. No claims are made to the originality of the methods, but it is 'felt that they may be new to some engineers and< interesting to others contemplating alluvial testing.

Jan 1, 1942