Search Documents

Plant-Based Trials of Monitoring of Coal Flotation Systems Using Electrical Impedance Spectrum Technique

Sep 13, 2010

By S R. La Brooy, T Giraudo, I C. Ritchie

The treatment plant at the Macraes Gold Project in New Zealand processes a carbonaceous, refractory sulphide gold ore. Since its commissioning in 1990, there has been a programme of continuous improvement of the plant, leading to higher recovery, increased throughput and low operating costs. During this time, a number of processes for treating both, or either, the preg-robbing carbonaceous fraction of the ore and the refractory sulfide fraction have been evaluated, trialed and utilised. The latest phase involves the installation by Minproc of plant utilising Newmont Gold's Pressure Oxidation Technology, a process which is anticipated to mitigate both problem factors when commissioned in 1999.

Jan 1, 1998

By P Mulvey

"Currently mine process studies and geochemical waste characterisation are considered as two interdependent studies, necessary for the development of the mine and inclusion in the environmental impact statement (EIS). Geochemical waste characterisation will utilise the simulated tailings produced by the mine process studies team to understand the behaviour of the tailings, but the two teams rarely integrate these to develop a coherent and agreed final design.Thorough mine waste geochemical assessments can develop processes to minimise environmental harm, resulting in substantial savings in the decommissioning, closure and rehabilitation phases, and may also be able to address changes in mineral processing methods that can result in substantial savings in process inputs, or even recovery of metal concentrates.Based on geochemical waste characterisation, the full cost of waste management can be calculated and incorporated into the costing of milling.  This allows for a more effective evaluation of the metallurgy.  A number of examples are presented in which substantial improvements have been made from the collaboration of both the metallurgical and geochemical teams during planning and the metallurgical team and environmental team during operations.*This paper is only available for individual download. It is not included in the conference proceedings*CITATION:Mulvey, P, 2013. Optimising metallurgy at the planning stage to minimise environmental impact - a feedback loop from geochemical waste characterisation, presented to MetPlant 2013 Conference (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By Solomons S. S, Tillmann V. H

The progress of longhole open stoping (LHOS) at Zinc Corporation Limited and New Broken Hill Consolidated Limited (ZC/NBIIC) is described together with the design of a novel sloped wall longhole stoping method which should allow the complete extraction of the orebody without the formation of pillars and with minimal dilution of the ore with sand fill.

Jan 1, 1981

A wide-ranging base of jig data was collected from various types of commercial jigs in 9 coal preparation plants in China, and a complete data analysis was made. It was found that the sharpness ofseparation was very variable, which demonstrates the complex interplay of the many factors which influence jig performance. Tests showed that there exist optimum frequency ranges in each compartment of a jig. Stepwise regression analysis indicated that the sharpness of separation is most sensitive to the intake fraction ofthe air cycle, the frequency, and the feed rate. By means of non-linear curve fitting techniques and statistical analysis, several mathematical models were developed to describe both partition curve and the jig performance, for simulation purposes.

Jan 1, 1986

By A Raza, D P. Kohn, D A. Foster, A J. W Gleadow

A large and increasing data base of apatite fission track results from sedimentary and granitic rocks exposed within the south-eastern highlands and along the continental margin ofAustralia provides constraints for the tectonic development of the south-eastern passive margin. The fission track results suggest that many regions of the south-eastern margin of Australia experienced distinct episodes of relatively rapid cooling during the middle Cretaceous to early Tertiary that can be attributed to the effects of rifting. One cooling episode is middle Cretaceous in age and related to denudation of the south eastern highlands from Tasmania to northern New South Wales between ~90 - 100 Ma. Rocks exposed along the present coast line record a later episode of rapid cooling, which is diachronous and decreases in age northward from ~80 to 90 Ma in northern Tasmania to southern New South Wales, ~60 - 80 Ma in central and northern New South Wales, and to ~50 - 60 Ma in southern Queensland. The results are consistent with models suggesting that underplating occurred inward of the rift along the eastern margin of Australia as a result of the onset of continental extension in the Tasman Sea at ~96 Ma. This resulted in a significant change in base level and km-scale denudation of much of the southeastern highlands. Subsequently, as breakup commenced during the Late Cretaceous at ~80 Ma and continued into the Paleocene at ~60 Ma, the second stage of cooling was imprinted on the rocks along the margin. This cooling is probably due to the relaxation of elevated geothermal gradients associated with rifting as well as some denudation. Because rifting was oblique to the present-day coast, different regions record different ages of cooling associated with the rift. The southern regions of New South Wales and Victoria yield ages associated with earlier rifting while regions of northern New South Wales and southern Queensland give ages associated with later rifting.

Jan 1, 1995

By Branagan D. F

The geology of the area studied is briefly described, together with the prospecting methods used in the search for copper, lead, zinc and uranium ore bodies.Four prospects, Mt. Corella, Yanasinga, Lawlor's and Greenmount, which were diamond-drilled, are described in detail and geochemical results are discussed in relation to the mineralization found. Copper anomalies were found wherever intrusive rocks were mapped, and showed a much closer relation to geology and mineralization than did the predominantly lead and zinc anomalies.Geochemical prospecting aids in the overall mineral search programme because of its speed and economy, as it helps to pinpoint areas worthy of detailed geological examination. Geochemical anomalies are a guide to favourable zones but may not indicate the presence of ore.INTRODUCTIONDuring 1953-55 the National Lead Company of New York carried out a search for minerals in an area south and west of Cloncurry (Fig. 1) in rocks of Precambrian age. After reconnaissance mapping, a number of prospects were chosen for closer examination by detailed geological mapping and geochemical sampling, and from these prospects, five sites were selected for drilling.This paper records the salient features of the exploration programme and discusses the geology and geochemistry of four of the prospects-Mt. Corella, Yanasinga, Lawlor's and Greenmount. Practically all the prospects examined showed high zinc "anomalies" or "dispersion" trains. Greta, Mt. Corella and Lawlor's prospects showed some copper anomalies and, to a lesser extent, lead anomalies. In particular, Greenmount exhibited striking copper anomalies.

Jan 1, 1960

By C Xuan, J H. Park, Q Wang, C Shen, D Kumar, W Mu

Dissolution of non-metallic inclusions in the metallurgical slag is of vital importance for cleanliness control of the steel manufacturing. With the development of high temperature confocal laser scanning microscope (HT-CLSM), new insights have been obtained due to its in situ observation characteristics, higher resolution and precise control. However, HT-CLSM measurement has the limitation, eg the slag composition cannot include high amount of transition metal oxides. In addition, it is time consuming for the experimental procedure and not so simple to succeed for every measurement. It is known that digitalisation has made a significant progress in recent years. Machine learning (ML), a sub-domain of artificial intelligence (AI), is the key enabling technology for the digitalisation of the material science and industry. The database for ML model is collected using almost all available HT-CLSM experimental data and subsequently the established database is trained by different ML methods. Unseen data is used as the benchmark of the ML model. Al2O3 dissolution is the main process to be predicted in the current study. A good agreement between the HT-CLSM data and the ML model prediction results show the possibility to apply ML in process metallurgy.

Jun 19, 2024

Kinetic Behaviour of Solid/Solid Separation of Ultrafine Particles in Aqueous Suspension

Sep 13, 2010

Mineral deposits of the central New Guinea region (Gunung Bijih, Ok Tedi, Mount Kare, Porgera, Frieda River) and of southeastern New Guinea (Wau-Edie Creek, Wafi, Hamata, Hidden Valley, Tolukuma, Misima) are associated with hot, forceful intrusions of magma of mantle origin that penetrated thick Precambrian and Palaeozoic continental crust. The interaction of high- temperature melt with continental crust, and the differentiation of melt while in transit through thick crust, may be factors in generating ore. Mineralised intrusives in central New Guinea are a result of Neogene- Quaternary magmatism and were emplaced in a foreland thrust belt environment, a setting similar to the (mineralised) Laramide intrusions of southwestern USA. In both cases, central New Guinea and the Laramide, magmatism is not obviously subduction- related. Mineralised intrusives in south- eastern New Guinea (Wau-Edie Creek, etc.), also, are in a thrust belt setting, and are not obviously subduction-related. The association of. gold in southeastern New Guinea with a second (Pliocene) phase of igneous activity, rather than with earlier (Miocene) activity suggests that re-working by successive intrusions may be a factor in localising ore. This is seen, also, in the Bismarck-Solomon islands region where the richer deposits are associated with later (Pliocene) intrusives rather than with earlier (Eocene-Oligocene) intrusives. Unlike the mainland mineral deposits, those of the Bismarck-Solomon islands are clearly subduction-related.

Jan 1, 1991

By Honeycombe R. W K, Greenwood J. N

Powder metallurgy has been developed rapidly in the last twenty years by overseas metallurgists. The technique of making the powders and their subsequent pressing and sintering into useful forms has' only been introduced into Australia under the stress of war-time economic conditions.The technique involved has very little in common with our usual methods of fabricating engineering alloys by melting the ingredients to a homogeneous mass, followed by casting to shape or casting to ingot form and shaping by application of pressure-so-called mechanical working. On the other hand, the technique includes operations, such as milling and sizing, familiar to the primary metallurgists.The compacting of metal or other powders finds important application in two outstanding fields of engineering production: (a) in making porous bearings and contact brushes, in which such a material as powdered graphite can be incorporated; (b) in making cutting tool tips of hard -carbides, which have a melting point too high to make casting feasible, and which would be too brittle in the cast condition in any case. In both these cases; the final article can be made of the desired shape and size (subject to shrinkage allowances) whilst the compact is in a soft and readily machined condition a consideration of great importance in connection with the hard carbides.In order to develop the necessary equipment and technique and at the same time to assisil in the war effort, it was decided to divert the research work of the Metallurgy Department of the University of Melbourne to the problems associated with the production of hard carbides from local raw materials and the sintering of such into tips for cutting tools. Since this work was started at least two industrial concerns have started to produce these materials in the Commonwealth.The work. to date has included (a) the purification of crude cobalt oxide from Risdon and the reduction of this to metal Particles of less than 10 p. diameter; (b) the production of tungsten powder from King Island scheelite and its conversion into tungsten carbide with particle size less than 4 p. diameter; (c) the sintering of the latter product, using the former as a bond; (d) the production of titanium carbide from titanium dioxide; (e) the separation of columbium and tantalum oxides from a Northern Territory tantalite, and the conversion of these into the respective carbides.

Jan 1, 1942

Structurally- controlled deep leaching processes have removed vast quantities of carbonate from a substantial portion of the "silica-dolomite" enclosing the 500 copper orebody. Mine drainage subsequently allowed free access of air to the porous environment created and oxidation of sulphides commenced. During the mIne development stage the exothermic and temperature-dependent nature of these hydrolysis reactions resulted in a slow general elevation of ground temperatures. and levels of 90 - lOO°C were attained in restricted moist sulphide-rich areas.With the advent of production and extensive use of explosives, the oxidation processes were locally raised to new levels of activity. Direct interaction of explosives and sulphides in favourable conditions caused temperature rises to above 260 C. Above this point the dry oxidation of sulphides in air was initiated and rapid escalation to the vicinity of 800 C has been known to occur in isolated cases.Ground reactivity is a function of the complex interrelationship of several controlling factors and no simple index exists.Control techniques are presently aimed at prevention of temperature rises in the range 100 -260 C. Inhibition of the rapid dry oxidation processes above 260 C is difllcult and current efforts have met with only partial success.

Jan 1, 1968

By Hart G. H

In tectonically disturbed zones within coal seams, decreases in the amount of kaolinite in the cellular structure of inertiniterich coal are accompanied by increasing kaolinite contents in fractures within the coal and/or rocks of immediately overlying horizons. This is due to fracturing of the inertinite microstructure by tectonic disturbance and remobilization and redistribution of free, fine-grained material (kaolinite and/or inertodetrinite.) Ascending waters are believed to transport the kaolinite in suspension, and redeposit it in the fractures and pores in the overlying horizons. This removal of material from the inertinite-rich coal leads to an increase in porosity (higher free gas storage), a presumed reduction in coal strength and an apparent increased proneness to instantaneous outbursts of coal and gas.

Jan 1, 1983

By L Lachance, F Flament, D Leroux, S GariTpy

"Considerable metal values are often locked in stockpiles (ore, concentrates, heap leach pads, slags, reverts, etc.) and process equipment (bins, holding tanks, thickeners, etc.). This is more than enough to justify accurate accounting of such in-process metal inventories from both financial accounting and operational perspective. However, accurately determining the metal inventory of an in-process unit is often a challenge in industrial practice. Audits have shown that available indirect or direct measurements often carry large inaccuracies. Sooner or later, ignoring these measurement errors lead to unexpected incoherencies in reported metal balances. In such situations, coherent metal balances are then achieved through subjective and sometimes significant adjustments of in-process inventory levels. While such metal accounting methods applied by mineral processing engineers used to be rarely challenged, they are now being increasingly scrutinised by various stakeholders. Hence, metal accounting procedures that mitigate subjectivity in adjustments while still coping with the unavoidable uncertainty are more relevant than ever.This paper reviews three different metal accounting methods for reporting in-process metal inventory values. Their individual application strongly depends on the available measurements i.e. The indirect method where the metal inventory of a given process unit is determined by subtracting the cumulative reclaim from the cumulative feed carries important flaws. The direct method also comes with challenging accuracy issues so that emptying a process unit is often the best available inventory measurement. This reality is recognised for by further analysing a previously proposed operating mode where two interchangeable process units are alternately used. The third investigated method is the redundant method which combines indirect and direct methods for a given process unit. This paper reveals that the dual process unit operating mode and the redundant method can both significantly improve the estimation quality of in-process metal inventories.CITATION:Lachance, L, GariTpy, S, Leroux, D and Flament, F, 2013. Review of metal accounting methods for in-process metal inventories, in Proceedings MetPlant 2013, pp 102-117 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By P N. Holtham

Magnetic separation is routinely used in the processing of titaniumminerals, and the efficiency of these operations can be determined bymeasuring the magnetic properties of the process streams. The valuable components in the feed to a titanium minerals plant have specific magnetic susceptibilities ranging from -10-9 m3 kg-1 (zircon) to 10-6 m3 kg-1 (ilmenite). However, in an industrial environment, in which the mineral temperature may range from 20 to 120¦C, it is difficult to measure susceptibilities lower than about 10-7 m3 kg-1. Hence laboratory testing of spot samples from magnetic separators is currently required to obtain accurate performance data. This is an inherently slow process and where feed grades are variable, optimum performance of magnetic separators is generally not achieved.This paper describes the development of an inductance-basedinstrument for measuring very low levels of magnetic susceptibilityon-line. The signal from the instrument can be used for process control purposes to maintain optimum magnetic separator performance.A prototype instrument has been installed in the zircon scavengercircuit in an Australian titanium minerals plant. The circuit consists of a roll magnetic separator treating a feed consisting mainly of monazite and stained zircon. The monazite-rich magnetic fraction is returned to the mine site for disposal, while the non-magnetic fraction is recycled to the zircon wet circuit. Splitter positions in the separator are adjusted when the final zircon product fails to meet specification, or the magnetic fraction contains more than 30 per cent zircon. Weekly composite grain counts show that sub-optimal operation of the magnetic separator results in significant zircon losses into the magnetics fraction.Using the instrument, the zircon content of this stream can now beaccurately determined from the measured magnetic susceptibility,provided a correction for the effect of mineral temperature is applied using the Curie - Weiss relationship.

Jan 1, 2001

By J Canterford

There is an apparent push to develop and commercialise "new and innovative" process flow sheets. A not-too-difficult reality check clearly demonstrates that the success rate of this push is not particularly significant and in fact could be regarded as a waste or misappropriation of R&D funding and the associated brain power. As Julian Sumner Miller would comment "why is this so?" To put it bluntly, many of the so-called innovative developments are equivalent to gold plating the dunny door - visually interesting but of very limited practical value. This presentation encapsulates some personal lessons learnt over the past 45 years.CITATION:Canterford, J, 2013. Developing a ænew and innovativeÆ process flow sheet - Traps for all players of all ages, in Proceedings MetPlant 2013 , pp 1-5 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By P J. White, J V. Lawless

Low-sulphidation epithermal gold deposits, which form in quasi-hydrostatic convective hydrothermal systems, frequently contain chalcedony within high-grade ore, which has been interpreted to be a crystallisation product of amorphous silica. To deposit amorphous silica rather than another silica polymorph at elevated temperatures requires very high silica concentrations, because of its relatively high solubility. Only extreme boiling caused by decompression followed by wall rock heating upon structural dilation, can achieve this. As gold deposits with amorphous silica it must be produced by the same mechanism, particularly since extreme boiling is also a very effective mechanism for gold deposition. Recent developments support this view; the first is the detailed isotopic analysis of chalcedony-bearing high-grade veins reported from Hishikari, Japan, in which oxygen isotope results are indicative of extreme boiling and hydrogen isotopes indicate initial deposition of amorphous silica. The second is the finding of chalcedony within geothermal pipe work in the Rotokawa geothermal field in New Zealand. Rotokawa is a comparatively hot field (335¦C at depth); hence separation of the steam-water mixture produced by the wells is undertaken at a comparatively high temperature (220¦C) to minimise down-stream silica scaling. Even so, silica scale, some of which is chalcedony, does occur, under similar conditions to that in low-sulphidation epithermal deposits. Evidence of chalcedony forming under these conditions, reinforces the interpretation that decompressive boiling is the main deposition mechanism for gold in low-sulphidation epithermal deposits. It is possible that there is sufficient drop in temperature due to decompression that, at least initially, the silica deposits directly as chalcedony. Low-sulphidation epithermal gold deposits that do not contain chalcedony, such as those in the Philippines, may form at temperatures too high for chalcedony to directly form. The recognition of decompressive boiling as the main deposition mechanism in low-sulphidation epithermal deposits means that exploration can focus on zones where this has taken place by combining paleohydrological reconstruction and structural geology.

Jan 1, 2002

Shaft sinking through an amphibolite-granite rock mass experienced rock bursts on the shaft walls and benches. However, rock burst phenomena was exhibited only in granite, which is e1asto-brittle with ability to store strain energy caused by orogenic and man made stresses. To improve ground conditions, blasting of destressing holes at shaft corners was carried out. By this technique rock burst during shaft sinking was minimized, but not eliminated.

Jan 1, 1982

The paper presents a brief history of endeavours to start a mining education programme which began in the days when Papua New Guinea's first large mine, at Panguna (Bougainville), was coming into production. The status of the Public Investment Programme in Mining Engineering and the facilities being created for the education and training of Papua New Guinean citizens in mining and mineral processing are also described. Future expansion plans are also detailed including those for the commencement of petroleum engineering and geological engineering which would include courses in mining geology, exploration geology, engineering geology and petroleum geology. The paper also looks at the manpower training requirements in the lower levels of mining industry such as pit foreman, blasting foreman and other similar positions. It stresses the need to start mining technical training programs at pre- employment level and at certificate level in a technical college, possibly Lae Technical Colleqe.

Jan 1, 1991

In New York City, on the walls of the library of the United Engineering Societies are these words:"Engineering-the art of organising and directing men and of controlling the forces and materials of nature for the benefit of the human race," but who, reading the schedules of even our best engineering schools, would infer that engineering is an art or that it should always havejn mind the benefit of the human race? While it must be remembered that our engineering schools exemplify the British cult of the amateur, that cult which lets men who have never attended a lecture on "Education" or perhaps nevereven read a book on it, become enginering teachers by profession (and so educators by inference), the root of the matter is to be found in the fact that our educational aims, and consequently our educational practice, seem suited much better to the position engineering held in the community in 1900 than to the position it holds to-day. This civilization of ours has developed, !;loth for good and for ill, into one based largely on engineering achievement; technical progress is so continuous and so rapid that thevalue of descriptive knowledge of current practice is ever lessening; enough must be imparted to make the young graduate immediately employable, and this amount is sufficient for illustrating the principles on which practice is based and on which its advance depends, but the young graduate's technical progress depends much less on his having acquired additional knowledge than on his ability to acquire knowledge, so, paradoxically, the more useful knowledge there is availabJe the less of it the student should be taught.Less conspicuous but fully as important is the enlargement of the field of work of engineering graduates, especially its extension to the initiating of policies and to the broader problems of administration. At present the road to such positions lies normally through a considerable period of professional work, but it is by no means unlikely that the field will soon include much that requires little professional expel'ience. At all events it is safe to say that the changed. and changing position of engineering in the communitydemands the attention of the engineering schools and that profitable discussion of engineering education demands some understanding of the real nature of education and of the part which engineering plays in the life of the community.THE NATURE OF EDUCATIONUnfortunately "to educate" supplies an example of how words degenerate in meaning; most people regard it as the equivalent of "to instruct"; a small number feel they have gone to. the root of the matter when they say...

Jan 1, 1941