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By Phelan JM

Poor selectivity in the separation of two sulphides generally arises because the flotation characteristics of the coarse sizes of the valuable mineral and finer sizes of non-valuable minerals are identical. Separat- ing the pulp into two size fractions at a specifically determined cut size and conditioning each size fraction with its own optimum reagent addi- tion is known to be helpful in improving such selectivity problems. The performance of the zinc section of the complex ore circuit at Wood- lawn Mines has been analysed in detail. The selective recovery of zinc was found to be a problem in zinc/pyrite separation. However, atypi- cally, the separation problem was between coarse zinc and coarse, not finer, pyrite. In spite of this the use of separate conditioning has effected significant improvements in rougher concentrate. Selectivity (and hence grade), overall recovery and flotation rate have all been enhanced. Dis- appointingly, coarse zinc recovery was not increased but, with careful optimization, this might be achieved without sacrificing the gains already realized. The technique of separate conditioning clearly has general application in other circuits where selectivity is a significant problem.

Jan 1, 1988

In 1985 BMR assessed Australia's economic demonstrated resources of mineral sands as follows: rutile 8.0 Mt, ilmenite 41.4 Mt, zircon 11.5 Mt, and monazite 229 000 tonnes. These resources are located along the east coast of Australia, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth, WA. However, over 40% of Australia's rutile and zircon resources, particularly those on the east coast, are presently not available for mining because of environmental considerations. As well, east coast ilmenite has been considered unsuitable for use by sulphate route pigment producers because of its relatively high chrome content. World demonstrated resources of rutile and zircon are estimated by BMR as 29 Mt and 38 Mt respectively. Demonstrated resources of ilmenite amount to about 1 billion tonnes. These occur predominantly in hard rock deposits in Norway, Canada, USSR and China, as well as alluvial deposits in Australia, South Africa and India. Quantitative data for world monazite resources is sparse. However, world production of rare earth oxides is now mainly from bastnaesite, a hard rock resource. Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. With the expected increase in Australia's rate of output of these commodities, combined with restrictions on mining along parts of the east coast, its position could diminish substantially over the next 25 years.

Jan 1, 1986

The Douglas mineral sands deposit is located 75 km north of Hamilton in western Victoria, Australia. The deposit was discovered in the late 1990s by Basin Minerals Limited and purchased by Iluka Resources Ltd in 2002. Prestrip mining commenced in December 2004, with ore mining commencing in August 2005. Douglas is the first of several projects being implemented by Iluka Resources Ltd in the Murray Basin, with all heavy mineral concentrate planned to be treated at the companyÆs mineral separation plant in Hamilton. The mineralisation at Douglas lies along the south-eastern margin of the Murray Basin. It is hosted by marine Pliocene Loxton-Parilla Sands and consists of three discrete deposits; Bondi Main, Bondi West and Bondi East. The mineralised sediments dip at a low angle to the west and lie unconformably beneath a veneer of top soil (50 - 100 mm) and subsoil (up to 600 mm) and between three to 12 m of overburden. The barren overburden, characterised by high clay content (<53 ¦m material) generally provides a stark contrast to the sandy ore, which is between 1 m (parts of Bondi East) and 15 m (Bondi Main) thick. Both overburden and ore are removed utilising standard dry mining techniques using both scraper-bulldozer and truck-excavator combinations. All ore is delivered to run-of-mine (ROM) stockpiles before being reclaimed by front end loader into the processing plant. Grade control at Douglas is based around visual dig control aided by high precision survey, which enables accurate reference to the resource drilling and block model data. Vertical excavator faces, inclined scraper faces plus regular test pits and trenches provide opportunities for in pit mapping and sampling. This data is used to refine not only the resource estimate for Douglas but also the drilling, interpretation and resource modelling methods used for similar deposits across the basin. The foundations of the geological reconciliation process at Douglas are the in pit surveys undertaken each time the mining fleet has completed building a ROM stockpile. These surveys and the subsequent interrogation of resource models enable robust estimations of the heavy mineral content of the stockpiles, which are subsequently used to predict the daily input grades into the plant during their reclamation. Reconciliation of this daily data is then undertaken at the end of each month against metallurgical production data and plant balances. Learnings and results from the reconciliation process are used to further refine subsequent resource models and modelling methods.

Jan 1, 2009

By Higuchi K

In this paper, the history of Japanese coal and gas outbursts is presented and circumstances and countermeasures at the time cf outbursts are summarized statistically. Then the present meth- ods for prevention used practically in Japan are introduced. From statistics, it was reconfirmed that Japanese coal and gas outbursts have occur- ed frequently in the district of geological disturbance, symptoms immediately before out- burst occurrence were the phenomena in connec- tion with failure of a coal seam and outbursts have occurred many times when the number of boreholes had not been sufficient to degas. One of the principal protective method adopted in Japan is the large diameter gas drainage boring which also posesses a stress relief effects. There is a tendency to make diameter of borehole larger to increase both stress relief and degassing effects.

Jan 1, 1986

By Mauk JL, Arehart GB

Quartz veins from the Martha Hill epithermal gold-silver deposit, Waihi, commonly exhibit crustiform banded textures. Visual differences observed between bands are primarily the result of a 1 to 1500 ¦m variation in quartz grain size. Quartz band textures are dominated by anhedral interlocking quartz mosaics, commonly associated with minor adularia and sulfide phases; these textures are interpreted to be products of amorphous silica crystallisation. The occurrence of rhombic adularia suggests that prolonged boiling influenced parent fluids. In contrast, the presence of coarsely crystalline bands, made up of subhedral to euhedral quartz grains, infers primary crystal growth from solution; evidenced by the occurrence of growth-zoned quartz within these bands. There is a narrow range of 3.3%o in 618Oq,,,,,= between maximum and minimum isotopic values for the deposit. Significant overlap in 618Oqu,, values are observed between the Martha and Welcome lodes. However, statistically significant and commonly systematic differences do occur between individual bands analysed in most samples. Temperature fluctuations may be the dominant factor responsible for observed inter-band variation.

Jan 1, 1995

Blast Engineers frequently use the terminology "the blast showed good heave", or even "the heave was better this time". It is reasonably obvious that "good" and "better" are not the best terms to use. It is also noted that any variation in the data can be misleading. The author proposes a more precisely defined and objective set of measures as tried and tested in a project in 1988. Simple objective measurements of a muck pile profile can measure 1. distance thrown 2. spread of material 3. heaping of material 4. skewness, or bias in the heaping 5. rotation of the mass This technique enables one to compare the profiles from different blasts without relying on subjective experience or judgement. Simple, artificial profiles will be presented to illustrate the problems of description; and then application of the measurement techniques to these profies will be discussed with physical interpretations. The mathematical techniques will be presented, and results of the application of the techniques to real data collected during research carried out at Baimsdale in Victoria, will be presented as illustration. The use of these techniques in mathematical modelling will be discussed.

Jan 1, 1990

By Yianatos J. B

The advances in the study of control alternatives for flotation columns are reviewed. An integral solution to the control problem has to deal with problems associated with instrumentation, process modelling, control strategies and control algorithms. The term hierarchical control is used here to mean the intelligent integration of available knowledge, control algorithms and logic rules of decision. The selection of information, algorithms and rules is based on the experimental and theoretical knowledge of the column flotation process. The software support was designed and implemented in object oriented computer programs. This technique allowed the implementation of a combination of control techniques, algorithmics and heuristics, in the form of a control strategy. This strategy has shown to fit well with processes exhibiting complex dynamic characteristics. The hierarchical control was implemented in a pilot column and included the following general aspects: co-ordination of distributed conventional control loops, use of sets of control parameters for the froth depth control loop according to the froth depth state, verification and diagnosis of sensors, on-line predictive estimation of gas hold-up, diagnosis of common operating problems and the use of predictive control to account for feed flowrate changes.

Jan 1, 1995

By Cunneen R. D, Murray A. M

Exploration in the vicinity of the abandoned Mt Coolon mine has shown that the shape and attitude of the quartz lode is controlled by the interaction between the lode and a converging syncline. Gold grades within the lode are enhanced along intersections with a welded ignimbrite, and decline rapidly where the lode intersects unwelded ignimbrite. Mineralogy and textures indicate the vein has an epithermal origin modified by a later intrusive event.

Jan 1, 1989

The ore deposits of the Oobar mining field are confined to sediments of the Early Devonian Cobar Supergroup. The mineralisation is discordant to bedding and parallel to cleavage. The structural association is variable with the deposits near the eastern margin of the Cobar Basin formed in zones of deformation and faulting. The Elura deposit located further to the west is in less deformed sediments within the core of a small anticline. There are wide variations in ore type fran lad sulphide chalcopyrite - pyrrhotite - pyrite to high sulphide sphalerite - galena - pyrrhotite - pyrite assemblages. The deposits ccnmonly contain an inner zone of quartz - sulphide - chlorite veining grading outwards into a chlorite halo containing quartz - carbonate veining. The Elura deposit differs in having an inner massive sulphide zone surrounded by a zone of big-Fe carbonate formation. The mineralisation probably formed during regional metamorphism and deformation in the Early Carboniferous. A possible genetic model involves the injection of metal bearing hydrothermal fluids formed in the upper mantle or lower crust up basement structures into the overlying Cobar Supergroup sediments. An alternate model proposes the leaching of metals from the sediments by brines formed during metamorphism and subsequent emplacement in favourable structural zones.

Jan 1, 1983

By S C. Dominy

For any gold deposit-based geometallurgical study, the collection and processing of representative samples for gold grade and recovery tests is critical. Sampling protocols should be designed to suit the style of orebody in question. The proportion and size of gold particles has a direct impact on the effectiveness of sampling protocols and metallurgical recovery processes employed. Studies focussing on ore mineralogy and gold particle deportment, size and distribution are required. Key issues are the presence of gold particle clustering (important for sampling optimisation) and proportion of coarse versus fine to refractory gold. X-ray computed tomography (CT) is a radiographic technique that produces high-resolution 3D computerised models of objects based on density distribution. The ‘virtual’ specimens are made up of voxels, the 3D equivalent of pixels each assigned a grey value based on X-ray absorption. This paper presents the results of recent research on the imaging of in situ gold particles in a coarse gold-bearing ore. The technique shows promise as a rapid non-destructive method for preliminary characterisation to facilitate more detailed studies. Early and rapid gold particle determination enables sampling protocol optimisation and metallurgical recovery parameters to be defined prior to detailed feasibility studies

Sep 5, 2011

By McGhie R. R

The general structural features and the principal mineral relationships of the Black Star ore body, Mount Isa, Queensland, have been described in several previously published papers. But particular reference may be made to the work of Grondijs and Schouten, whose examination of over 200 polished sections revealed some remarkable features in the process of ore deposition. The observations by the present authors are based upon the study of a smaller ·set of specimens complementary to those examined by Grondijs and Schouten and are intended to elaborate certain aspects of the mineral relationships, more particularly those affecting the ore-dressing processes.The work described applies to the primary sulphide ore only, and to the present milling practice of fine-grinding and selective flotation.GEOLOGICAL FEATURESThe Black Star is one of several economic mineral concentrations in the Mount Isa series of thinly bedded carbonaceous shales, which are considered to be of preCambrian age. The nlineralization is apparently connected with pegmatite intrustions located within some miles of the ore bodies, and has been Gontrolled in the main by major folding of the shales and by a shear system which follows approximately the strike and dip of the beds. The detailed "The investigations described in this paper were made in the Metallurgy Department, University of Melbourne, where the senior author was formerly Senior Lecturer in Mining and Metallurgy. A report on a section of the work was submitted by the junior author as a thesis requIred by the University of Queensland.

Jan 1, 1939

By Mogi G, Akaike A, Yamaguchi U

A new algorithm has been investigated for three-dimensional open pit designs to improve the dynamic cone approach which utilises the dynamic programming technique. The conventional dynamic cone method was improved by introducing examination processes: 1. whether any negative blocks are included in a unit cone or not; and 2. whether it is possible or not to leave the negative blocks unmined in the unit cone without disturbing the geometric condition imposed on the slope angle of the cone. The newly developed algorithm was applied to a large-scale open pit copper mine in a planning stage and the results have been compared with those obtained by the conventional methods.

Jan 1, 1995

An assessment has been made of six reported methods for the determination of the swelling of iron ore pellets on reduction. The methods are discussed on the basis of apparatus requirements, reduction conditions, sample requirements, measurement of swelling and reproducibility. It is concluded that the CNRM, LKAB, and Lurgi methods are the most satisfactory which presently exist for determination of the swelling of industrially produced, iron ore pellets.

Jan 1, 1974

By Needham RS

Hydrothermal mineral deposits are the dominant mineral deposit type in the Cullen Mineral Field, and have been important sources of tin, tungsten gold, silver-lead, zinc and copper. The deposits are mostly in north to northwest-trend- ing shear zones, and are confined to Early Proterozoic contact metamorphosed metasediments or synorogenic to postorogenic granitoids. The distribution of the vein-type deposits with- in the contact aureole defines a district-scale metal zonation of uranium closest to granitoid, through tungsten, copper, tin, silver-lead to gold with increasing distance from granitoid contacts. This zonation probably reflects de- creasing temperatures within the contact aureole during granitoid emplacement, and at the time of generation of a variety of metal-bearing fluids. A magmatic source for some of the metals is indicated by the positive spatial relationship between uranium, tungsten, copper and silver-lead deposits and granitoids abundant in those metals. There is little evidence for any such relation- ship for tin and gold deposits, except for an association of some tin deposits with tin-enriched mafic rocks. Most of the granitoids with anomalous metal values are late stage highly fractionated leuco- granitic phases forming younger plutons peripheral to the main body of the Cullen Batholith, They probably form cusps connected to the main body at shallow depths.

Jan 1, 1984

By Larsen D. F

Minor iron formation related base metal sulphide mineralization occurs in granulite facies metamorphic rocks of the early Proterozoic Willyama Complex. Rock sequences hosting three iron formation related Cu, Zn, Pb prospects from the Thackaringa Group (Suite 3) are described. A caparison of host rock sequences, style of mineralization and facies of iron formations suggests major differences in terms of the overall depositional environment. However, significant similarities are present with respect to the nature and distribution of iron formation facies and the occurrence of chlorite 'alteration' zones in close proximity to mineralization in all cases. The chlorite within these zones occurs in a number of diverse forms in a range of rock types. A comparison of the prospects shows that there is no evidence to indicate that the chlorite in the zones is a retrograde alteration product of former higher grade prograde mineralogies - the chlorite appears to have survived granulite facies metamorphism. The mode of occurence of the chlorite in the 'alteration' zones together with the fact that the association quartz + chlorite + magnetite + pyrite + base metals is cx rmn to all areas suggests that the chlorite is specifically related to the processes which deposited the stratiform iron formations and related sulphides. It is considered that the chlorite precursor was a prenetanorphic alteration product or chemical sediment closely related to submarine hot spring activity which was also the source for chemical sediment precursors of the iron formations, associated lode rocks and Sulphides.

Jan 1, 1983

By Weller KR

A study of high pressure rolls grinding of a number of Australian ores and minerals has been carried out using a pilot-scale machine with rolls 300 mm diameter and 70 mm wide. The results from this study have been used in conjunction with plant survey data to construct computer simulation models of various comminution circuits and these have been used to investigate options for incorporating high pressure grinding rolls into these comminution circuits. Possible rolls options for three of these circuits are presented, and likely energy savings over the existing circuits are discussed together with potential improvements in plant throughput and/or product sizing. A scale-up procedure for predicting full-scale machine performance from small-scale testing is described, and the effects of rolls operating conditions are also discussed.

Jan 1, 1991

The screening of iron ores, sinter and coke, and investigations undertaken to improve screening efficiency and cloth life are discussed. The major modifications to coke screening proposed with the construction of No. 7 coke ovens battery are briefly described. The major problem areas were identified as screen cloth blinding and pegging, feed presentation and screen overloading. Blinding and pegging have had a significant effect upon screening efficiency with the screening of sinter, coke breeze and wet iron ores in particular. Pegging can be reduced or eliminated by the correct selection of aperture size and shape, screen excitation and slope, and screening medium. Blinding encountered with wet coke breeze was a particular problem in which no significant progress was made.

Jan 1, 1984

By Dugan K. J

Mine operators are currently in a situation where market forces are acting to reduce profit margins and at the same time, regulatory bodies are insisting on improved mine safety and stability. This means that ground support must be made more cost efficient while maximising operator and equipment safety.A key aspect of ground support efficiency is the 'in the ground' performance. This paper discusses the factors that influence the way rock bolts and cable bolts perform. It highlights the need to know how support efficiency varies in different ground conditions.

Jan 1, 1992

By Draper J. J, Jell J. S

The Burdekin Basin in the Townsville hinterland is an intracratonic extensional basin which contains up to 4500 m of marine and continental siliciclastics and carbonates. The basin sequence is recognised as having accumulated during five major episodes of deposition. Facies analyses of these show that each consists of one or more transgressive or regressive phases. Each episode led to the accumulation of thick sequences in several half-grabens in a transtensional back-arc setting. The depositional episodes can be recognised in comparable sequences in the Broken River Province to the west and Drummond Basin to the south.An Early Devonian episode resulted in the deposi-tion of dominantly marine facies, currently mapped as Fanning River Group, in the northern part of the Burdekin Basin. Two transgressive phases are recorded there, firstly in the Pragian, then later in the late Emsian to early Eifelian. A Middle Devonian episode is represented by dominantly marine facies of the Fanning River Group, representing the peak of a widespread late Eifelian to Givetian transgressive phase. A Late Devonian episode is characterised by continental facies of the Dotswood Group. Deposition occurred during a major regressive phase in response to regional uplift of surrounding areas, and the onset of acid-intermediate volcanism to the south. A Late Devonian to Early Carboniferous episode followed, which was a period of alternating marine transgressions and non-marine regressions that resulted in the deposition of the Keelbottom Group. A final Early Carboniferous episode, marked by the deposition of calc-alkaline volcanics and non-marine faciesòof the Glenrock Group, was a direct outcome of Early Carboniferous subduction further to the east. Compression of the basin followed in the Late Carboniferous, resulting in folding and reactivation of basement faults.

Jan 1, 1990

By D Morgan, D Sato, B Lumsden, S Senanayake

Laboratory flotation tests on fresh cyclone overflow samples are a useful tool to troubleshoot and indeed to improve plant performance; however, reproducibility between laboratory flotation test and plant performance is important for interpretation of the laboratory tests and hence their usefulness. Chemical reproducibility can be achieved with the addition of the required reagents; however, reproducing the physics of forces and energy in a 5 L cell compared to a 50 000 L plant cell or a 500 000 L plant cell is not generally studied or discussed. For some tests such as collector evaluation the physics of the flotation process may not be critical, but for some evaluations in the laboratory, it can be important.All flotation plants suffer from losses of valuable <20 µm mineral. Selective mineral aggregation has long been recommended to improve the poor flotation recovery of <20 µm sulfide minerals; however, successfully testing any type of selective sulfide mineral aggregation’s effect on flotation recovery in the laboratory on practical plant samples requires reproducing plant cell physics. The energy input per litre and the forces in a laboratory cell are vastly different to a plant cell. Reproducibility between laboratory and plant tests requires that these differences be minimised. The physics of the laboratory flotation cell is particularly important when fine mineral aggregation tests are carried out.This paper outlines a modified laboratory aggregation and flotation method that closely reproduces plant performance in a laboratory test.CITATION:Sato, D, Lumsden, B, Senanayake, S and Morgan, D, 2014. Development of a laboratory flotation method to test plant mineral aggregation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 173–178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014