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By S Moradi

The thickener overflow of zinc concentrate, obtained from flotation process in the Angouran plant located in Iran, contains a large quantity of slimes which were transferred to the tailing ponds. These slimes have caused problems of storing and environmental aspects in the Angouran area. The objective of this research is to describe the extraction of zinc from these slimes by leaching method using sulfuric acid in pilot plant scale.Chemical analyses showed that these tailing materials contain 35 per cent of zinc. By XRD analysis, smithsonite is identified as the major constituent. Calcite, dolomite, and cerussite are found as carbonate minerals. A minimal amount of Zn occurs as hemimorphite. Quartz, kaolinite, clinochlore and muscovite are other silicate minerals in the slimes.In the optimal conditions, ie acid leach at pH of 1, temperature of 55¦C, reaction time of 120 minutes and solid-liquid ratio of 1:3 and neutralisation with Ca(OH)2 at pH = 4.5, temperature = 70¦C, time = 90 minutes, the total recovery of zinc obtained was 95 per cent.

Jan 1, 2004

The last two years have seen a rapid change-over from mechanised cut and fill. stoping to the more economic and productive long hole open stoping method, such that today more than 80 per cent of total production is won from open stopes. At first drilling was by sub-level rings and/or parallel up and down holes from inter- mediate sill horizons using conventional exten- sion rod equipment. Sub-levels were developed no more than 40 metres apart to allow accurate drilling. Compact, crawler mounted in-the-hole hammer equipment was introduced as soon as it became available in Australia. Today, all open stope drilling is done with three Atlas Copco ROC306 rigs and two Ingersoll-Rand CMM jumbos. Fans of 115 mm diameter holes, varying from near vertical down holes to horizontal, are drilled with a burden of 3 m. Toe spacing varies from 3.5 m to 4 m. An Atlas Copco DG418 booster compressor is used to boost run-of-mine air from 700 kPa to 1400 kPa in the areas of longest drilling. This has improved overall drilling performance in these areas by 40 percent.

Jan 1, 1977

China has at least 200 collieries suffering from the problem of instantaneous outbursts of coal and gas. Strong outbursts often have occurred in geological tectonic zones and concentrated stress areas. There are some particular characteristics of these strong outbursts, including the effects of ground stress, gas pressure and the properties of coal associated with the outbursts.

Jan 1, 1986

All sections of our community are becoming increasingly aware of the dangers of uncontroll- ed erosion associated with modern earthworksy whether they be concerned with the protection of capital structures, reforestation of mine tailings or generally the aesthetic and ecol- ogical impact. Because of the many ecological variances and climatic conditions no single technique may be offered as the complete answer. Rather that a combination of a series of techniques is nec- essary to achieve an individual end result. These techniques may appear to be expensive initially, but when considered in relation to the overall cost, and we realise that this work represents our only insurance of the stability of our project, the cost of stabilisation is insignificant. Once erosion has commenced the cost of stabilisation escalates dramatically which highlights the definite need to include the requirement of stabilisation in early design of your projects. Stabilisation should commence during construction to ensure that control of mobile soils is gained at the earliest possible time.

Jan 1, 1976

By Spark R. F

The copper deposits at Pernatty Lagoon are predominately djurleite-digenite bodies beneath the permanent water table, and chrysocolla-atacamite-malachite above the permanent water table. The minerals havebeen deposited as sheets, lobes, and pods in zones suggestive of permeability channels or permeability basius with respect to groundwater circulation.Pyrite is deposited in the form of framboids, which reflects its biogenic origin. Copper-iron sulphides deposit by replacement of pre-existent pyrite, and rarely by direct deposition. The latter mode of formation results in complex crustification bandings of chalcopyrite, bornite, sulphur rich bornites, digenite, and blue remaining covellites. The copper-iron sulphides appear to reequilibrate under constrained oxidation, resulting in an iron depletion and associated copper enrichment, the final product of which is a djurleite-digenite assemblage and associated with goethite. Where copper mineralization/ host rock relationships have rendered the rocks entirely impermeable to post ore groundwater movement, then the copper-iron sulphides are preserved as the ore assemblages.Minor and trace minerals observed include sphalerite, carrollite, galena, wittichenite, and possibly tetrahedrite in the primary ores. In the oxidized ores cllprite, tenorite, and trace brochantite have been found.

Jan 1, 1976

The production of copper by the Outokumpu direct blister process commenced in July 1988. The problems and incidents encountered in commissioning the main smelter equipment are outlined. Early difficulties were encountered in process control, hot metal handling, dust buildup in the off gas handling equipment, waste heat boiler tube failures, foam over of hot metal into the waste heat boiler and failure of ancilliary equipment.

Jan 1, 1989

By Hall K

The Osborne copper gold mine, 100 per cent owned by Placer Pacific Limited, is situated 195 kilometres south east of Mount Isa. The orebody is broadly categorised into three main ore zones; oxide, transitional and sulphide copper. Copper oxide

Jan 1, 1997

By S Strohmayr, R Harvey, A See

Ernest Henry Mining Pty Ltd started production in August 1997. The Ernest Henry orebody consists of two distinct parts, a complex supergene ore zone overlying a primary ore zone. The economic copper minerals in the supergene ore were chalcocite, bornite, secondary chalcopyrite and native copper while the primary zone has only chalcopyrite. The variability of the supergene zone made concentrator operation difficult and predicting metallurgical performance using mineralogy essential to establish the capabilities of the concentrator. A paper presented at the 1998 Mine to Mill Conference entitled Mineralogy Controlling Metallurgy at Ernest Henry Mining (Barnes, Strohmayr, Brindley and Munro, 1998) presented the testwork and initial plant surveys that showed that the mineralogy of the ore controls the metallurgy of the concentrator. This paper presents the data obtained from the subsequent years of operation treating both the supergene and primary ore types. A review of the actual supergene mineral distribution in feed and subsequent recoveries compared to those predicted as part of the flowsheet design is also presented.

Jan 1, 2003

The underwater test is now being used routinely to characterise explosives and initiators. However, several outstanding issues regarding the role of confinement and the usefulness of the test results in predicting expected blasting performance require further elucidation. This paper reviews the underlying principles governing the test, and highlights its relative advantages and disadvantages in product development and applications. It deals with topics of energy release, energy partitioning, confinement and efficiency, supported by illustrative examples from tests with various products and geometries. The results are analysed in terms of both the detonation parameters measured and their extension to predicting blasting performance in the field. It is emphasised, that just as with other performance tests, the results and conclusions are only valid under the particular test conditions employed, and over-generalisation of these results can lead to erroneous conclusions.

Jan 1, 1999

By Johnston G, Revy T

Dominion Mining Ltd. and the JKMRC have conducted a detailed investigation of the performance of two of Dominion Mining's gold treatment plants (Haveluck and Paddy's Flat). In terms of design each plant is considerably different. The Paddy's Flat plant uses a single stage SAG mill with recycle crusher, followed by single stage ball milling. The Haveluck plant uses the more traditional approach of multi-stage crushing and ball milling. The performance of these two plant designs in terms of energy efficiency and cost of comminution equipment, developed at the JKMRC, to accurately predict both power draw and size reduction characteristics at these plants is evaluated.

Jan 1, 1991

Victorian brown coals occur in massive deposits, the quality of which is determined in the first instance by means of samples taken from exploratory bores. As a number of important utilisation characteristics are connected, not with the relatively homogeneous organic mass of the coal, but with minor components such as the ash content and particular constituents of the ash, it is necessary to know how bore samples relate to coal finally used in the process concerned. Tests are described in which the statistical parameters associated with bore sampling, operational sampling and sample reduction and laboratory procedures including a range of coal analytical methods were determined. These indicated properties where analytical errors were relatively high and where sample reduction procedures contributed substantially to imprecision in results. They also showed the effects of the non-homogeneity of brown coals with higher than normal ash contents. A further experiment explored the relationship between samples taken at various stages in the course of test boring, digging, and burning a defined 'block' of coal, and demonstrated an apparent increase in the proportions of adventitious mineral constituents as the 'intensity' of sampling Increased.

Jan 1, 1976

The southern portion of the Swan Coastal Plain, a geomor-: phological element formed since late'Tertiary times, contains commercially exploitable accumulations of ilmenite, zircon, rutile'and monazite associated with a series'of raised'shorelines. The:location'of the deposits is controlled by a locally outcropping*Archaen-granite/granulite complex and a sea':current pattern'determined'by'local geography and a prevailing wind direction.'-A progression from medium. to high titanium ilmenite is'evident parallelled by. progressive leucoxenisation as the age of the deposits increases. Variation's in trace element content accompany this process. Circulating groundwater has caused vertical mineralogical variations within-individual deposits and' by p'ecipitation of iron has formed layers of hardpan. The economic sig- nificance''of the Geographe--Bay deposits is'briefly discussed,

Jan 1, 1964

By Waldram JT

The Kelsey Centrifugal Jig incorpo- rates the principles of operation of a conventional mineral jig, at the same time utilising high centrifugal forces to extend concentration to very fine heavy minerals. The main operating variables which are adjusted to control processing of different types of material are centrifugal force, ragging material and size distribution. Pilot plant trials have been under- taken to examine concentration of a mineral sand in which the heavy mineral particles occur mainly in the minus 0.075 plus 0.032 mm size range. Stage recoveries of greater than 90% were achieved at concentration factors of up to 2, although lower recoveries were obtained with higher concentration factors. A final concentrate containing 65% heavy minerals was obtained.

Jan 1, 1986

By Howell IJ, Kirsopp R

In June/July 1981 Mount Isa Mines Limited was confronted with a crisis situation in the crushing operation of the Lead/Zinc and Copper Concentrators. Three crusher mainframes developed serious cracks in the upper rim area. The type of cracking indicated that major failure of these mainframes could be imminent. Operational crushers could not be sensibly inspected and it was therefore assumed that more than three mainframes were seriously cracked. The crisis was averted as described in the following text.

Jan 1, 1978

Mount Isa Mines Limited commissioned the Heavy Medium Plant in August 1982. The first processing stage using Mogensen Sizer 2056 dry screens, experienced unresolvable cloth blinding problems in attempting to separate fine, damp Lead/Zinc ore at 1.7 mm. A large proportion of the fines incorrectly reported to oversize and hence to the wet preparation screens. This wet preparation screen overloading produced multiple operating and maintenance problems. The plant configuration precluded retrofitting any alternative proprietary screen. An internal Mount Isa Mines research and development programme was established to design and build a screen to achieve the required per- formance within the site constraints. The resulting ISA SIZER screen has exceeded metallurgical performance expectations. A `clean sheet' approach to the design also permitted elimination of maintenance difficulties experienced with the Mogensen Sizer. Four `production model' ISA SIZERS were installed in February 1988. The ISA SIZER screen, now fully developed is available commercially and will satisfy many screening plant requirements.

Jan 1, 1988

The Green Parrot and Reward stratabound silver-lead (copper-zinc) deposits are located in the eastern part of the Arunta Block. At Green Parrot, mineralisation is contained within a north-south striking lode horizon comprised of elongate lenses of massive garnet or calcsilicate-carbonate "lode rocks" with intercalated sericite-biotite schist and laminated biotite-feldspar schist. The "lode rocks" are increasingly calcareous to the west. The mineralisation is broadly zoned with an increase in lead content and decreases in copper and silver contents from east to west. The principal sulphide minerals are galena, sphalerite and bornite. The Reward deposit lies adjacent to a lens of massive garnet "lode rock" which is contained within garnetiferous sericite-quartz schist. Primary mineralisation consists of galena, chalcopyrite, sphalerite and pyrite. Both deposits are associated with a substantial thickening of the lode horizon which is narrow and discontinuous along strike from the Green Parrot and Reward deposits.

Jan 1, 1984

By Campbell D. L, Nutt C. J

The Delta two-degree quadrangle is located in west-central Utah, in the eastern Basin and Range physiographic province but near the intersection of the Basin and Range, Rocky Mountain, and Colorado Plateau provinces (Fig. 1). The quadrangle lies in the region of interior drainage that includes western Utah and most of Nevada, and, like the rest of that province, it has an arid climate. This work is part of the United States Geological Survey's ongoing CUSMAP (Conterminous United States Mineral Assessment Program) project in the Delta quadrangle. Trace-element geochemical data presented here includes information from approximately 600 heavy- mineral-concentrate and 2500 rock sample sites from throughout the Delta quadrangle.

Jan 1, 1988

Before any accident prevention and total safety programme can succeed, a safety concientiousness or attitude needs to be implanted in the employees' minds. Psycholog- ical and physiological conditions play a vital role in accident causation and prevention. Both need attention in a good safety programme, but working place conditions and environment are more easily corrected. However, the challenge is to change attitudes in the minds of men - psychological factors in accidents. To do this does not require a Safety Officer, but does require a Safety Adviser. At Blackwater mine a Safety Adviser is available to all sections of the organisation to guide and assist, to provide data and material to use at meetings, to help in accident investi- gations and to help organise training. To eventually achieve total commitment requires every member of the management team to be a salesman towards all around selling an attitude to safe working, a way of life. At Blackwater mine the workforce is young overall with most employees being under 40 years old. Psychologically this is a quite different problem to a balanced ages working group. A great deal of effort is needed to communicate with the younger, articulate, better educated employee who is also generally a skilled operator in the capital intensive

Jan 1, 1975

Exploration by Cyprus Minerals Australia Company (formerly Amoco Minerals) has successfully outlined significant Au-(Cu) mineralisation at Starra, 150 kilometres south-east of Mt. Isa. Mineralisation is stratabound and localized in deformed and metamorphosed ironstones (B.I.F?) and iron-oxide bearing schists of the mid-Proterozoic Staveley Formation. Over 90% of the presently outlined potential ore occurs in 4 discrete zones within a strike length of 3.5 kilometres. The inferred geological resource in these zones is approximately 6 million tonnes grading 5 grams per tonne gold and 2% copper. Roughly half of this is open-pittable, but more rigidly applied mining criteria will probably reduce the exploitable tonnage. Detailed infill drilling is in progress and a pre-feasibility study has commenced. The joint venture partners, Cyprus Minerals (75%) and Elders Resources (25%) expect to make a development decision by the end of this year.

Jan 1, 1986

This paper outlines the thermodynamic and mass balance principles which affect the distribution of cobalt between matte and slag during the pyrometallurgical treatment of nickel-copper sulphides and considers the implications with regard to maximising the recovery of cobalt from the smelting and converting circuit.

Jan 1, 1994