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By Ibil S

The Gameta Gold Deposit is located on the north-eastern corner of Fergusson Island in the D'Entrecasteaux Islands of Milne Bay Province, PNG, at lat. 9¦ 25' 5, long. 150¦ 47' E or AMG co- ordinate 256740 E/8959000 N (Figure 1). The area is covered by the Fergusson (SC56-05) 1:250,000 scale Topographic Map Sheet and the Koitabu (9079)1:100,000 scale Topographic Map Sheet. The property is held 100% by Union Mining NL (UMG) and lies 105 km NNE of Alotau and 33 km to the ESE of UMGs recently developed Wapolu Gold Mine, a Joint Venture between UMO (51%) and Macmin NL (49%). The inferred resource estimated from surface results and 105 RC drill holes, currently stands at 1.89 million tonnes at 2.6 git gold (1.0 g/t Au cut-off) or 155,000 oz. Evaluation of the property is currently proceeding. To date 111 RC holes have been drilled for a total of 4611 m.

Jan 1, 1997

Gold mine production in South America was 247.3 tonnes in 1995 up from 156.4 tonnes ten years earlier in 1986. This represents a 58 per cent increase and amounted to 11 per cent of total world gold mine production. The major countries involved in order of production, were: Brazil (67.4 tonnes), Peru (51.5 tonnes),. Chile (48.5 tonnes), Colombia (24.1 tonnes), Venezuela (17.1 tonnes), Bolivia (16.0 tonnes), Ecuador (9.6 tonnes), Guyana (8.8 tonnes), French Guiana (3.3 tonnes) and Argentina (one tonne). The most dramatic increase was reported in Peru where production increased from 10.9 tonnes in 1986 to 51.5 tonnes in 1995, heavily influenced by the production from Minera Yanacocha which began operations in 1993 and produced 17.2 tonnes in 1995.With the reformation of the mining laws and the introduction of investment incentives in all the South American countries in recent years, dozens of major and junior mining companies began flocking into the area in the early-1990s to conduct exploration. A recent study undertaken in Brazil shows that an average of $240 million per year will be expended in this country during the period 1993 - 2010. Twenty-five per cent of this expenditure is expected to be made on gold exploration. Similar figures for Peru are $220 million total per year with 50 per cent for gold; $170 million per year in Argentina with 25 per cent for gold and $120 million ner year in Chile also with 25 Der cent for gold.

Jan 1, 1997

By Strickland R. E J

Heap leaching is establishing itself as an efficient method for the extraction of gold from low grade ore. It has the advantage of low capital costs, low operating costs and rapid startup. However, not all ores are amenable to heap leaching. It is only applicable to well oxidized ores that have reasonable permeability characteristics. Ore with excess fines or clay often display low permeability and are unsuitable for heap leaching.In this study, an attempt has been made to increase the rate of cyanide leach solution percolation by flocculating clay particles or reducing the surface tension of the leach solution. A wetting agent was found to decrease the rate of gold dissolution, possibly by presenting a hydrophobic surface to the gold particle. Flocculation of the clay increased the solution flow rate. The flocculation agent had no affect on the total gold leached but decreased the leaching rate.

Jan 1, 1992

By S Sims, A Stradl, G Hope, B Lacouture

Column flotation cells have been installed in numerous base metal operations around the world. The majority of these cells utilise conventional air-only spargers to introduce air into the bottom of the column. The recent development of instruments to measure the bubble characteristics in these columns has provided a renewed understanding of column behaviour. These new tools provided insight into why the columns at Red Dog Mine had never performed up to expectations. After efforts to optimise the spargers failed to substantially change the bubble size and air efficiency, alternate sparger systems were investigated. The Metso Minerals CISA Microcel sparger system appeared promising and was selected for a full-scale plant trial. The Microcel sparger system was originally developed for the coal industry at the Virginia Centre for Coal and Minerals Processing. In October 2003, a Microcel was retrofitted into one of two 3.66 m diameter flotation columns in the zinc retreat circuit at Red Dog Mine. The operation of the two different sparger systems in parallel allowed a detailed comparison. This paper discusses the performance of the Microcel based on the data collected during several detailed surveys. Bubble size measurements carried out in the pulp zone using the McGill University bubble viewer showed a significant difference in bubble size. The mean Sauter diameter of the bubbles decreased from 3.4 mm for the jetting-type sparger to 1.9 mm for the Microcel sparger. The overall recovery and the recovery by size fraction for both valuable and gangue minerals were compared. Paired t-tests demonstrated that the Microcel column produced a higher concentrate grade (0.6 per cent zinc absolute) and a higher unit recovery (2.8 per cent zinc absolute) than the existing Canadian Process Technologies Inc (CPT) SlamJet column. These improvements provided a payback period of 1.5 months for the $109 000 investment.

Jan 1, 2005

By LaBrooy S. R

Crushing for the gold industry involves fine crushing and a degree of primary milling, and this presents new problems and challenges, partiuclarly on many of the new ore-bodies now being opened up. All of this calls for a better understanding of some of the basics of fine crushing and milling. Accordingly, in this paper the "typical" contemporary Australian gold mining operation is firstly delineated, in terms of representative ore types and typical crushing and milling tasks. Then some of the technical and economic basics related to fine crushing are re-examined, including: energy relationships in crushing and milling; concepts of reduction ratio; recirculating load controversies; and questions of realistic economics in crushing gold ores. The economics of the typical gold mining operation are shown to be rather marginal; not the lavish "bonanza" many may imagine. Likewise, crushing cost expectations are frequently quite Unrealistic.

Jan 1, 1987

By B Lance, D O’Brien

The Hidden Secret ore body is located within the Mt Charlotte underground mining system in Kalgoorlie, Western Australia. Mineralisation of the Hidden Secret ore body is lode style and therefore differs from the typical economical mineralisation mined at Mt Charlotte and consequently demanded a novel approach to the mining methodology. The ore body is lens like in shape, extending 200m along strike, 210m vertically, and dipping at 55 degrees. The lode width varies from 1.5m at the extremities to over 22m in the central zone of the ore body. Average grade is 3.4 Au grams per tonne. The initial mining methodology was Modified Avoca utilising Longhole Open Stoping with pillars, in a bottom up stoping sequence. However, as Hidden Secret became better defined and wider than initially modelled, it was identified that a high portion of gold would remain in the pillars and other mining concerns emerged such as remote backfilling large open voids and potentially unsafe vertical standoff distances between levels and wide open stopes. A re-evaluation of this method was undertaken and a new approach adapting a variation of Avoca methodology was identified to remove the rib pillars and replace them with a sill pillar separating the 4 levels into 2 distinct blocks. This new approach provided an immediate advantage by removing the bogger backfilling activity from the same level of the active stope front, enabling stope drilling and prepping to occur during the backfilling cycle. Bogging productivity has also improved as the fired ore is funnelled to the draw point by the backfill rill, significantly reducing the requirement for remote bogging thus improving bogging productivity. This mining method is currently in progress in the first of the two mining blocks and is on track to realise the targeted recovery of 7,700 ounces from the rib pillars.

Mar 15, 2021

By Gardavsky V, Gabell AR, Green AA

The I,)hyllosilicate mineral chlorite is a common constituent of altered rocks associated with volcanogenic massive sulphide deposits, and literature studies indicate that, in general, this mineral is progressively enriched in magnesium relative to iron as an orebody is approached. Studies have shown that there is a direct correlation between the Mg/Mg + Fe ratio of chlorite and its absorption spectra in the 2.7 to 3.0 um range. However, this region, which contains the fundamental 0-H stretch absorption features, is affected by intense atmospheric absorption, and therefore cannot be used for remote sensing. At shorter wavelengths (0.4 - 2.5um), there are windows where the atmosphere is sufficiently transparent and vibrational absorption bands still occur, although they are clue to overtones and combinations, and accord- ingly are much weaker than the fundamental features. Shifts to longer wavelengths with increasing iron content can still be observed in this region of the spectrum and, with better spectral resolution and sensitivity, it may be possible to monitor subtle variations in chlorite chemist by remote sensing techniques.

Jan 1, 1987

In the Massif du Sud ophiolite complex platinum group elements occur predominantly as ultrafine-grained inclusions of rutheniridosmine, laurite and iridosmine. These form primary inclusions less than 5 to 10 um in diameter within chromite in podiform chromitite fringed by dunite, and emplaced subsequent to solidification of the host harzburgite. There is no specific association with trace inclusions of transition metal sulphides. The crystallization of then: Ir. Os and Ru minerals may have occurred concomitant with hromite, perhaps related to more reducing conditions produced by crystallization of the chromite. The Ir, Os. and Ru show pronounced fractionation from Pd, Pt and Rh expected to be also present in the mantle source rock. The dunite shows evidence of metasomatic origin from adjoining harzburgite, and the possibility of selective crystallization of the Ir sub-group elements suggests that Pd, Pt and Rh may have been transported elsewhere.

Jan 1, 1989

By S Johnston, L Howe, S Stevens

Regulators have an important role to play in fostering and enabling reliable, effective, environmental management. Given this, it is perhaps surprising that there has been relatively little debate on exactly how regulators can enhance their own approaches, in order to promote improved outcomes overall. The authors argue that applying research on High Reliability Organisations, as well as the University of Pennsylvania’s Penn Program Framework for Regulatory Excellence, to regulators has the potential to facilitate positive environmental results across the mine life cycle.

Aug 2, 2023

The non-renewable energy resources of Queensland comprise coal, petroleum (oil and gas), oil shale and uranium. Coal is widely distributed., and has been developed extensively both for export and for use within the State. Proven reserves total 5 390 million tonnes recoverable of coking coal and 5 580 million tonnes recoverable of non-coking; very large resources particularly of non-coking coal are still to be quantified by further drilling. Annual production is of the order of 20 million tonnes of coking coal, principally for export, and 6 million tonnes of non-coking, mainly for power generation within the State. Petroleum resources are meagre in com- parison with those of coal. Initial recover- able reserves of liquids (mainly in the now substantially depleted Moonie Oil Field) totalled only 4.2 million m3. Initial recover- able reserves of gas (mainly in the western Surat and Bowen Basins) totalled 7 800 million m3. Annual production is of the order of 64 thousand m3 of liquids for refining in Bris- bane, and 268 million m3 of gas mainly for production of fertiliser and for industrial and domestic heating, in Brisbane. Prospects are fair for the discovery of additional reserves. Two deposits of oil shale are potentially of economic significance. The Rundle deposit at The Narrows in central Queensland has the

Jan 1, 1979

By Mills KW

Coal mine pillar design formulae available to mine planners are typically based on relationships determined for specific site conditions. Application of these methods is difficult when other factors, relating to mining or geological conditions, not specifically addressed in these relationships are encountered. A review of pillar design methods, coal strength properties and relevant field monitoring of pillar behaviour has shown pillar strength and deformational characteristics are extremely sensitive to in situ behaviour of the rock and other material components that make up the coal pillar system. A method has been developed that has been found to provide excellent correlation between existing field data using the strength and deformational characteristics of materials determined in selected laboratory tests. This method is based on definition of the loading conditions, accurate modelling of the strength, confining conditions and deformation occuring in the roof, floor and coal seam and definition of the in situ strength of coal based on underground monitoring of appropriately sized coal pillar. The design method is considered to provide an accurate and rigorous pillar design method that will give mine planners a more rational mine design capability which is based on the mine geometry and geological setting of the operation. It is envisaged that availability of such a method will allow significant optimisation of pillar layouts and more closely define the geological and mining issues that relate to pillar design optimisation.

Jan 1, 1992

By M Sebbag, T Taimre

Barrick Gold Corporation is proceeding with development of the Buzwagi Mine in the Lake Victoria Greenstone Belt District of Tanzania. The Buzwagi orebody occurs in the Nzega Shear zone within the Greenstone Belt and is hosted in a K-Feldspar rich granite in contact with mafic volcanic. The orebody presents 2.6 M ounces in 41 Mt of reserves, at 2.0 g/t. Over the ten year mine life, total material movement will be 261 Mt. The feasibility study was completed in 2006 and presented several technical challenges. Two principle challenges are grade control and the impact of dilution on the economic viability of the project. The principle challenges for grade control will be quality control and quality assurance in the sampling of the massive coarse grained granite, which comprises 70 per cent of the deposit. The principle challenge with dilution will be with the selective mining of the narrower mineralised zones contained within the mafic volcanics. This paper will focus on the mine planning methodology which has been applied including selective mine unit (SMU) and dilution estimation, net smelter revenue (NSR) calculation and the effects of cut-off grades to the project economics and mine schedule.

Jan 1, 2007

By E Werner, B R. Leavitt

The chemistry of acidic mine drainage discharging from flooded coal mines is commonly reported to improve with time after flooding. This investigation describes a 18-year dataset of post-flooding water chemistry for a below-drainage underground coal mine within the northern Pittsburgh coal basin (Pennsylvania, USA). The Montour mine is a 5650-hectare below-drainage coal mine of maximum 260 metres depth. Montour was closed in 1980 and flooded to within 38 metres of land surface within 4.8 years. Pumping averaging 210 L/s was then employed to maintain water levels at this elevation. The flooded proportion of the mine (by volume) at full flooding was 56 per cent. The shaft where water was pumped from Montour for water control is located about 70 per cent of the distance between the mine water table and the back of the mine ù that is, it is close to the back of the mine. The residence time (total water volume at flooding divided by pumping rate for control) is estimated at 5.6 years. Time series of chemical analyses show three phases of chemical behavior in post-flooding discharge. In Phase I (zero to two years after flooding), iron concentrations were high and reached their maximum (1100 mg/L). In Phase II (two to four years after flooding), a transition was begun to alkaline conditions, with decline in iron and other solutes. In Phase III (>4 years), net alkaline conditions began, with iron concentrations declining exponentially to 50 per cent of mined volume. This attainment of net alkalinity in this case may have also depended on abundant calcite in overburden extended up to 30 m above the mine floor.

Jan 1, 2003

By Baird G. R, Jurak R. N

In this study Dynamic Finite Element Modelling is used to investigate the distribution of peak particle accelerations (PPA) induced in a rock mass by a vertical decked column of explosives. The rock mass is assumed to be viscoelastic. The influence of the delay time between decking charges, the viscosity attenuation (quality factor Q), the decking configuration, and the velocity of detonation (VOD) on PPAs is examined. The results of this paper are relevant to fragmentation since the nature of the fragmentation is related to the stress magnitude and hence the PPAs. It was found that increasing the VOD, and increasing Q increases the PPAs in the neighbourhood of the blasthole. However, the VOD and rock quality factor Q have little influence upon the distribution of PPA. It was also found that an even distribution of PPAs, at a fixed distance from the blasthole, could only be obtained by increasing the ratio of charge length to stemming length. The study showed that the amplitudes and distribution of PPA surrounding the blasthole was approximately independent of the delay time between the decked charges. The modelling also shows that the particle accelerations at locations below the bottom of the charge are relatively small and so the model predicts no substantial damage below the bottom of the charge after blasting.

Jan 1, 1995

Project-finance risk assessment is mature and approached systematically. Mining industry due diligence remains fragmented with specialists addressing different aspects of the project such as reserves/JORC, environmental impact, commodity market, even financial analysis/ modelling. Each professional has a natural tendency to believe that the risk factors they have examined are the key ones necessary to be reviewed, as if their review will stand in isolation from others in the way a project materialises. By first laying out the project risk categories and risk matrices, this paper examines the due diligence process with a keen eye to the risk assessment and overlap/interaction. Some cross fertilisation of due diligence techniques from other industry sectors is placed into the mining context. Six case studies are then presented with regards to due diligence features in each projectÆs feasibility review or financial information/ offering memorandum. A power case first shows the differences between the due diligence expectations of banks versus bond financings. Then some Australian and Indonesian mining development cases are analysed to see the due diligence learning points. Some of these were project/due diligence failures. The conclusion focuses on the value of a systematic risk assessment for project evaluation, all from the project-finance perspective.

Jan 1, 2007

Mineralisation adjacent to Herberton occurs within three main subcentres. The Her- berton Hill subcentre is characterised by the association of Sn,W the Herberton Dividing Range South subcentre by Sn, and the Herberton Dividing Range North by Cu, As. The relation- ships between the subcentres are discussed in terms of metal distribution, production, deposit types, wall rock alteration and re- lationships with granitoid intrusives. The temporal and three dimensional spatial re- lationships between the centres are uncertain.

Jan 1, 1978

Reduction of Iron Content from Silica by Gravitational Processes In this research work, it was attempted to reduce the iron contents (Fe2O3) in silica sample which was provided from Shenin silica mine using gravitational processes including jig machine, multi gravity separator (MGS), shaking table and spiral. The silica sample contains 93.75 per cent SiO2, 0.44 per cent Fe2O3, 2.78 per cent Al2O3, and 0.08 per cent TiO2 and the Fe2O3 has to be reduced to about 0.1 per cent or less than 0.02 per cent. Mineralogical studies and XRD analysis indicated the presence of haematite, pyrite and goethite as the major iron impurity phases. Mineralogical studies of polished and thin sections yielded that the degree of freedom of silica is more than 80 per cent in the range of -300 +212 mm. After elimination of fine particles, at first nine tests were carried out on crusher product (in two size fractions), wet rod mil product and scrubber product by means of Jig Machine. The best results were obtained with about 0.15 per cent Fe2O3 on rod mill and scrubber product which was not desirable. Thereafter 7 tests were carried out using shaking table; the best results were obtained with about 0.14 per cent Fe2O3 on rod mill and scrubber product which was not desirable. MGS showed the worst result in order to iron removal from silica which was not desirable. Finally 9 testes were carried out using spiral whish is the best gravitational separator for elimination of iron impurities from silica. The best result of spiral tests were achieved on scrubber product. In this test concentrate weight percent and its Fe2O3 grade were 82.32 per cent and 0.085 per cent respectively. Finally a test was carried out using 2 stages of spiral in order to develop flow sheet. In this test concentrate weight percent and its Fe2O3 grade were 78.8 per cent and 0.1 per cent respectively. This product can be used to produce float (clear flat) glass.

Sep 13, 2010

By C Munro, S Emery, M Flynn, K Tan

"AEROPHINE® 3418A Promoter is a well-known and widely used collector and is an industry standard for its excellent selectivity and efficacy in the processing of complex polymetallic sulfide ores, particularly those containing silver. Until now, however, it has not found widespread use in primary nickel flotation.In an effort to increase nickel recovery without compromising selectivity over iron sulfides, Western Areas Forrestania Nickel operation trialled the use of AEROPHINE® 3418A as a secondary collector at low dosage. A series of ON/OFF trials were conducted, with the finding that a very low dose of AEROPHINE® 3418A increased nickel recovery by 0.6 per cent compared to using xanthate alone.This paper provides a brief operational history and overview of the Forrestania operations, a description of the trial and an analysis of the results.Citation:Emery, S, Flynn, M, Tan, K and Munro, C, 2016. Aerophine® 3418A Promoter as a Secondary Collector to Boost Nickel Recovery at Forrestania Nickel Operations, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 145–148 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

The problem of instantaneous outbursts remains unsolved after over a century of events and the investigation of the mechanism of the phenomenon and means of treating it. Outbursts have occurred of up to 5,000 tonnes with perhaps up to 500,000 m3 of accompanying gas, either methane (CH4) or carbon dioxide (C02) or mixtures. The low density of CH4 and the high density of CO2 give particular problems. Australia with both gases has experienced outbursts for 85 years with fatalities as recent as 1978. The Bulli Seam of the Illawarra area of the Sydney Basin is affected and outbursts with both CH4 and CO2 occur. The Northern and Central Bowen Basin also experiences outbursts with both gases. Proneness of affected mines is related to the high rank of the'coal and the proneness of the seams-is localised according to depth, gassiness, structure and development geometry. Proneness may be reduced by appropriate choice of mining methods. In addition to outbursting mines other mines have symptomatic phenomena. Traditional preventive methods have been used and control by induce- ment has been practised. A method of local prediction for widespread use has not been achieved although locally successful prediction 1Superintendent Rock Mechanics and Strata Control, The Broken Hill Proprietary Company Limited, Steel Division Collieries, Wollongong, N_RW

Jan 1, 1980

By Wilson CJN

The central Taupo Volcanic Zone is a region of intense Quaternary silicic volcanism accompanying rapid crustal extension. Modem central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at c. 0.28 m' s'. The rhyolites show no major compositional changes with time, but the total extent of magma chamber zonation has changed with the advent of rifting and crustal extension at c.0.7 Ma. At least 34 caldera-forming ignimbrite eruptions have formed a complex sequence of relatively short-lived, nested and/or overlapping volcanic centres in central TVZ. Taupo contrasts with other large silicic magmatic systems in the exceptionally high frequency, but small size, of caldera- forming eruptions. This contrast reflects the thin, rifted nature of the TVZ crust, that precludes the development of long- term magmatic cycles at Taupo.Within central TVZ, non-rhyolitic compositions have been erupted apparently irregularly in time and space; in particular there is no evidence for a geographic separation of basalts from andesites. TVZ is a rifted arc, but its segmented nature, high thermal flux and voluminous rhyolitic volcanism make it unique on Earth.

Jan 1, 1995