Search Documents

Cyanide-extractable gold is far more meaningful in the definition of ore, and control of extraction, than fire- assayable or aqua regia digestible gold. The use of cyanide- extractable gold addresses the significant problems of over- as well as under-assaying by fire and aqua regia digests. The problems of conventional control or diagnostic cyanidation extractions: lengthy extraction, and masking by pregrobbing in cyanidation extractions for assay purposes; are surmounted with a novel activator - Leach WELL. Full extraction of liberated gold, insignificantly affected by preg-robbers, can now be achieved within 30 minutes. This can assist in reducing common gold losses presently often hidden by inappropriate mine call factors, and/or high grade cut values. This paper includes a discussion of fundamental mechanisms of cyanidation, preg- and assay-robbing, which underlie the phenomena Involved.

Jan 1, 1992

Nauru Phosphate, which is one of the world's highest grade deposits discovered to date, contributed in 1969, 2.2 million tons of the total world production of 77.7 million tons. Phosphate production, which is the major source of revenue for the island nation, is carried out by the Nauru Phosphate Corporation, headed by a Government appointed Board of Directors. The complete mining operation, including ship loading techniques, is discussed along with proposals at present being investigated to upgrade the Quality of the product.

Jan 1, 1971

By J A. de la Torre, I R. Cerna, G K. Karadjian

The La Colorada underground mine in Zacatecas, Mexico is a mechanised cut-and-fill silver mine with a capacity of 1250 t/d. The project focused on training the mine’s experienced operators for a fleet of underground trucks, through the use of a training simulator. The project was run by the simulator vendor, in collaboration with the mine’s maintenance, safety and production management.A training program was created targeting maintenance reduction, productivity improvement and increased utilisation and availability. Operators were first acclimatised to the simulated environment, had their current performance baselined, then received targeted coaching, with the process repeated to reinforce learnings. Concurrently, production, maintenance, and safety data was being measured in the real world to measure skills transfer. Due to limited telemetry available from the equipment, many of the data points for the project were sourced from maintenance logs, and accounting data.Equipment failure data measured from unscheduled maintenance records showed an overall 6.5 per cent decrease in unscheduled maintenance following the implementation of the training program. This rate of reduction correlated with the significant decrease in equipment abuse behaviours measured within the simulator during this period. Additionally, overall maintenance activities showed a significant decrease, confirming that reductions in unscheduled maintenance were not achieved through increases in scheduled maintenance. The reduction in equipment damage also increased availability and utilisation of the truck fleet. This highlights that the maintenance improvements not only reduced maintenance costs, but made the fleet available for more production. Moreover, the variability of the operator performance was decreased by 86 per cent, and the difference between their best operator and the worst is less than the baseline; this showed a gap where machine abuse, productivity and cost are impacted directly.This project illustrated that even small-scale mining operations with an experienced operator workforce can achieve positive return on investment (ROI) from simulation-based training. It also highlights that in the absence of equipment telemetry, alternative data sources such as accounting data and maintenance logs can be used to quantify ROI from training.CITATION:Karadjian, G K, de la Torre, J A and Cerna, I R, 2017. Innovations in underground hard rock operator efficiency – through simulation-based training technologies and processes, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 53–58 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By R Stosch, D Lohberger, J Rodler, E Schnell and A Bassler, H Ramseier

In the last two decades three-dimensional (3D) computational fluid dynamics (CFD) simulations have become an important tool in engineering sciences. More recently, the safety requirements in underground railway stations have increased with regard to incidents. For this reason, existing underground stations (eg Munich, Strasbourg and Berlin) are being equipped with smoke extraction facilities to protect passengers from smoke and visibility impairment in the event of fire. In addition, designs of planned underground stations (eg Karlsruhe, Doha) also include these facilities.For the commissioning of ventilation engineering systems with complex structures, the functional testing of the whole technical installation are important, as are the acceptance tests of ventilation and equipment parts. This functional testing includes not only the technical inspection of the equipment but also the acceptance measurements of the capability of the equipment and the execution of hot- or cold-smoke tests to confirm the effectiveness of the ventilation system.Due to the fact that the overhead contact line and other sensitive installations were already installed in the tunnel roof at the time that smoke tests were proposed, hot-smoke tests with fire loads up to a maximum of 1 MW could only be executed. Therefore, the evidence of the attainability of the safety objective had to be provided computationally in this special case with a fire scenario of a heat release of 10 MW using CFD simulations.This paper presents the interplay between the results from acceptance testing and smoke tests and the use of 3D CFD simulation and virtual reality using the example of Allmend station, which was repositioned underground and is part of a new section of track from Lucerne railway station to Kriens in the Zentralbahn network. The steps of the verification and validation of the computer model are presented with the real tests and measurements.CITATION:Stosch, R, Ramseier, H, Lohberger, D, Rodler, J, Schnell, E and Bassler, A, 2014. Safety in underground railway stations – an example of the interplay between testing and 3D computational fluid dynamics simulation, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 103–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Sutherland R. A, Rawling K. R

The Nanisivik Mine is located 750 km north of the Arctic Circle at the north end of Baffin Island in the Canadian High Arctic, and has been in production since 1976. The paper describes the regional and local geology and the current mining and mineral processing operations, including recent innovations in each area. The Nanisivik zinc-lead deposits comprise Mississippi Valley type sulphides in a block-faulted sediment sequence of Proterozoic age. The deposits formed in two mineralizing stages by replacement of the carbonate host rock. Exploration techniques adapted to the permafrost environment include high frequency EM and ground probing radar. Core drilling is done with calcium chloride brine but trials with heated flushing water indicate potential for cost reduction. The predominant mining method at Nanisivik is room and pillar. Cut and fill is used in some satellites to the main zone. Due to the permafrost, dry drilling is employed in the underground mining. The permafrost enhances ground stability, permitting large underground openings and, as a result, the use of relatively large scale mining equipment. For power conservation, a remote control system for the ventilation fans has reduced mine power costs. The milling of the simple coarse-grained ore in an arctic environment requires special techniques in the design and operation of the plant for materials handling, utilisation of waste heat, reagent selection and tailings disposal. Regulated heavy metal contents in effluents discharged to the sensitive environment are achieved by natural processes. A recent change from sub-aqueous disposal of tailings to beach type deposition within a cell in the tailings area is reviewed. Planning closure of the property presents special problems and an opportunity for innovative techniques. Approximately 25 per cent of the employees at Nanisivik are drawn from the Inuit population of the Canadian Arctic. As the first permanent industrial activity in the High Arctic some innovative approaches to employee relations were required which have resulted in a very stable, culturally mixed community in a remote location.

Jan 1, 1993

By Grano S. R, Ralston J

It is the perennial problem most metallurgists face when examining data collected from laboratory float tests and plant surveys - there are more numbers than we know what to do with! The objective of this paper is to analyse and interpret a set

Jan 1, 1994

Broken Hill is situated at an elevation of approximately 1000 ft. above sea-level, on the Barrier Ranges, in the State of New South Wales, Australia. It is approximately 700, 280 and 330 miles from the ports of Sydney, Pirie, and Adelaide, respectively.The summers are usually hot and dusty, with a recorded maximum shade temperature of 114° F. The rainfall averages approximately 9 in. per annum.

Jan 1, 1932

The radiolarian biostratigraphy of the western part of the Gympie Province, north of Brisbane, has been examined. This part of the province comprises mainly the Amamoor beds and the Gympie Group, which have been assigned Permian ages on the basis of localised marine macrofossils. This study has shown that the Amamoor beds and the Gympie Group include older strata than previously supposed.The Amamoor beds consist of at least two tectonic units, namely a melange unit (unit A) and a well stratified sequence of sedimentary rocks (unit B). The former unit, regarded as an accretionary subduction complex, contains chert blocks ranging from Late Devonian to Earliest Carboniferous, while the latter unit yields Permian radiolarians. Latest Devonian to Earliest Carboniferous bedded cherts occur in sequence previously mapped as Amamoor beds and Gympie Group.

Jan 1, 1990

By BLAKE DAWSON WALDRON

I must acknowledge my strategic adviser, Mr Lance Grimstone, who contributed to the development of this paper, and collated the text and figures.

Jan 1, 1994

By P Sha

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Elaine Dorothy Cu-Au (REE-U) skarn deposit in the Mt Isa Inlier, Queensland, Australia is characterised by extensive metamorphic calc-silicate hornfels long before hydrothermal skarn and complicated deformation history. The deposit is hosted by the Corella Formation (1780–1740 Ma) and exhibits two phases of skarn formation in the study area – banded fine-grained diopsidic hornfels (Phase 1) and coarse-grain pyroxene skarn (Phase 2). Phase 1 skarn is predeformation and is interpreted to have been caused by the 1743–1734 Ma Burstall Magmatic Suites, whereas the coarse-grained pyroxene skarn (Phase 2 skarn) postdates the deformation and peak metamorphism events. Phase 2 skarn consists of prograde pyroxene, less garnet and titanite, retrograde epidote, REE-allanite, amphibole, biotite, and later sulfides, carbonate, quartz, anhydrite and chlorite. It hosts most of the copper mineralisation, with the REE elements occurring mostly in allanite. Titanite coexisting with allanite and Cu-Fe sulfides in Phase 2 skarn has been dated by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) at 1524 ± 9 Ma (207Pb/206Pb). The ages are similar to Williams-Naraku Batholiths, which outcrop approximately 40 km to the east in the Eastern Fold Belt. In Elaine Dorothy, the isotopic compositions for calcite cluster around 12.2‰ d18O and -3.7‰ d13C. It probably resulted from a mixing processes between marine sourced carbon-oxygen (ca 20‰ d18O and -0.5‰ d13C) and other distinct geochemical reservoirs, eg magmatic C-O. These features indicate that Phase 2 skarn and Cu-Au (REE-U) mineralisation may be related to unexposed intrusions at deeper levels.CITATION:Sha, P, Spandler, C and Chang, Z, 2015. Elaine Dorothy Cu-Au (REE-U) skarn deposit, in Proceedings PACRIM 2015 Congress, pp 445–450 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

In June 1996, Nord Resources Pacific (Nord) decided to work towards obtaining all necessary approvals from the government of PNG for a mine on Simberi Island in the Tabar Island Group, New Ireland Province. On the 9th of September 1996, Nord submitted a Proposal for Development and an application for a Mining Lease to mine the oxide gold deposits on Simberi Island. The Mining Lease was granted on the 3rd of December 1996 in a signing ceremony on Simberi Island. This was achieved in the extremely short time frame of less than 3 months and this paper attempts to explain the processes which made it possible.

Jan 1, 1997

Backfil ling of excavated Sub Level Open Stopes has been underway since March 1989 and as at December 1992 some 1 100 000 cubic metres of Cemented Aggregate Fill have been placed. During these three years significant developments in fill quantities, types and cost have taken place.Operational improvements have reduced the quantity of Cement Aggregate Fill by 40 per cent. These results have been achieved by:ò rescheduling stopes,ò designing smaller primary stope, and ò use of uncemented rockfill.Unit cost for Cement Aggregate Fill have fallen in the order of 50 per cent through:improving fill hole reli ability,simplified barricade construction procedures, reducing the cement content,ò substituting dune sand for deslimed mill tailings, ò improved maintenance at the Backfill plant, and ò renegotiated site freight agreement.This paper will review the historical developments of backfill use at Olympic Dam.

Jan 1, 1993

This paper discusses the recently com- pleted TBM-driven pressure tunnel at the Sand Bar Hydroelectric Power Project. The Sand Bar Project is a diversion scheme situated on the middle fork of the Stanislaus River in the Western Sierra Nevada, California, U.S.A. As part of the project, a 5.6 km long and 3.71 m diameter unlined pressure tunnel was bored by a Jarva TBM at the average rate of .37.5 m/ day. This report deals with construction aspects of the tunnel, including TBM performance, lining design, and remedial support measures. Correlations between TBM performance, geologic conditions, and rock properities are made, and the Contractor's mode of operations are discussed. Advance rate prediction, and the impact of these excellent advance rates attainable in hard rock using the new machines are discussed.

Jan 1, 1987

By W D. Erskine, M J. Saynor

Ranger Uranium Mine, surrounded by Kakadu National Park is located in the Alligator Rivers Region (ARR) in the wet-dry monsoonal tropics, 250 km east of Darwin, Northern Territory. A trial landform (TLF), measuring approximately 200 m by 400 m (8 ha) was constructed during late 2008 and early 2009 by Energy Resources of Australia (ERA), adjacent to the northwestern wall of the tailings storage facility at the Ranger Mine. A collaborative research program involving the Environmental Research Institute of the Supervising Scientist (eriss) and ERA, has been underway to measure long-term (five to ten year) rainfall, run-off, sediment and solute losses, seepage and vegetation establishment on the TLF (Saynor et al, 2012; Lowry et al, 2014). This paper reports on bed load losses from four erosion plots built on the TLF. These were achieved by physically isolating approximately 30 × 30 m areas from the surrounding landform on three sides with sidewalls along with an open polyvinyl chloride (PVC) pipe on the downslope side. Each plot was instrumented with a range of sensors. Two plots, 1 and 2 were constructed on waste rock material, while plots 3 and 4 were constructed on waste rock mixed with approximately 30 per cent lateritic material. Plots 1 and 4 had tube stock planted in early 2009, and plots 2 and 3 were initially planted by direct seeding in July 2009 and were infill planted with tube stock in January 2011.CITATION:Saynor, M J and Erskine, W D, 2016. Bed load losses from experimental plots on a rehabilitated uranium mine in northern Australia, in Proceedings Life-of-Mine 2016 Conference , pp 168–171 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By Leahy G. J, Moxon N. T, Nicol S. K

Experimental work is described in which extremely dilute aurocyanide liquors are treated with novel surface-active complexing agents to produce a hydrophobic aurocyanide species. Subsequent aeration of these liquors causes accumulation of such species at the air-water interface and the aurocyanide complex is transferred to a froth concentrate. A detailed performance assessment of this process is made and this knowledge used in the design of a pilot plant facility. Early results indicate the feasibility of the selective recovery of aurocyanide ions from reclaimed residue dam water (approximately 0.2ppm Au) with upgrade ratios of the order 180:1. A further study was made applying ion flotation to the recovery of gold from a carbon-in-pulp (CIL) feed liquor (approximately 1.0ppm Au). The probable economics of this process compared to conventional CIL processing is also described. Successful development of countercurrent ion flotation for concentrating solids-free gold solutions may offer a lower cost alternative to existing gold ore processing technologies, or in more secondary applications such as concentrating dilute gold solutions or heap leach runoff. The technology may also have more generalised applications to other heavy metal process- Ing.

Jan 1, 1991

The words ""Uncertainty"" and ""Risk"" pervade every discussion about mining exploration and investment. Perhaps these terms are subjectively understood by industry professionals, but objective portrayal of these concepts outside the industry is a woefully undeveloped science. This paper addresses current industry understanding and practice regarding quantitative risk assessment techniques, and provides examples of the application of three of these techniques. Probabilistic techniques for financial risk assessment are valuable adjuncts to conventional financial analysis, and address a range of issues not assessable by any other means. The value of whole-of-project probabilistic risk assessment is currently debatable for decision-making purposes, but is seen as important as a mechanism to focus attention to the critical issues that ultimately impact on project success. The dissection of project capital into risk and non-risk components provides valuable insights into risk characteristics not readily quantifiable in any other way. This technique also provides a framework for more objective ""what if?"" scenario evaluation and for the capital structure of resource projects. Finally, mechanisms for the valuation of undeveloped reserves are examined, and guidelines suggested. The importance of reliability in production cost estimates is highlighted and the impact of early development on reserve valuations is discussed. The importance of economics throughout all stages of the evaluation process is fundamental.

Jan 1, 1994

By L Stitz, S Kinnear, L D. Fabbro

Sensitive and tolerant species of macroinvertebrates were present across a wide range of conductivity concentrations in the Isaac River catchment in Central Queensland, indicating the need for further ecological studies in the field to underpin the development of regionally-tailored guidelines for conductivity. The Isaac catchment has naturally high conductivity, but there is also increasing pressure on resource companies to ameliorate saline mine water discharge. Recently, catchment management efforts have included a revision of the water quality guidelines that are specific for the broader Fitzroy catchment. These guidelines include the use of macroinvertebrates as indicators of ecosystem health, but developing and applying such guidelines first requires a good understanding of macroinvertebrate ecology and population dynamics, ideally from field validation. To date, studies of macroinvertebrate tolerance to conductivity in southern freshwaters, as well as in laboratory-based ecotoxicological tests conducted in Queensland, have suggested that ranges exceeding 1000 ¦S/cm are likely to have negative impacts on survivorship of all taxa. However, these results may not be transferable to natural populations of macroinvertebrates from the Isaac, where the naturally high-conductivity water may allow the opportunity for adaptation. To test this, macroinvertebrate assemblages were examined at a series of sites in the upper Isaac River catchment at the end of the dry season in 2012. Patterns in the assemblages were examined together with water quality parameters, in order to gauge the ability of macroinvertebrates to survive at conductivity concentrations exceeding 1000 ¦S/cm. The specific conductance of the field sites ranged from 477 ¦S/cm to 9791 ¦S/cm and a total of 39 families from 13 orders were identified. Species richness was not significantly different between sites of differing conductivity. Macroinvertebrate populations were dominated by Dipterans as well as the traditionally more pollution-sensitive families Ephemeroptera and Trichoptera. There was an absence of any correlation between conductivity and species richness (P > 0.050), suggesting that macroinvertebrate taxa richness occurs independently of conductivity, at least in this particular cohort of mining and/or grazing influenced ephemeral systems in Central Queensland.CITATION:Stitz, L, Fabbro, L D and Kinnear, S, 2013. Macroinvertebrate tolerance across a range of conductivities in the Isaac River Catchment (Central Queensland), in Proceedings Water in Mining 2013 , pp 135-142 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

A summary of the more important work by previous workers is followed by brief descriptions of the rock formations and regional structure. Type examples of the various forms of mineralization are described and the conclusion is drawn that there has been one main period of ore formation, namely, during the "Viti Revolution" in the mid or late Miocene.INTRODUCTIONThe Crown Colony of Fiji is comprised of a group of some 250 islands situated between latitude 160 sand 21 0 S and longitudes 1770 E and 1780 w: By far the greater, part of the total area, 7,083 sq. miles, is contained within the two main islands, Viti Levu 4,053 sq. miles, and Vanua Levu 2,128 sq. miles, and it is to these that most geologists have directed their studies. The most detailed work has been in the Tavua Basin, north coast of Viti Levu, centering about the mining town of Vatukoula and the geology of this area forms the subject of a separate paper by Blatchford (this volume p. 13).The present contribution summarizes geological knowledge of Fiji, at the time of writing (Feb. 1952), with particular reference to the known mineralIzation, but excluding the Tavua Basin. For general descriptions of Fiji's topography reference should be made to the recent works of Derrick and Dunkin.PREVIOUS WORKERSPeriod 1840-1930Prior to the gold rush of the early 1930s the visiting geologists concerned themselves in the main with the struc...

Jan 1, 1953

By Dean J. A, Taube A, White A. H, Messenger P. R, Jones I. W O, Huston D. L

The 50 million tonne Mount Morgan gold-copper deposit (4.99 g/t Au, 0.72 per cent Cu) was an irregular pipe-like body of quartz and pyrite, with subordinate chalcopyrite, magnetite and gold. Mineralisation was hosted by the Middle Devonian Mine Corridor Volcanics which occur as a roof pendant within the Late Devonian Mount Morgan Tonalite. On three sides, the deposit was enclosed by a series of normal, concave, listric faults and surrounded by outward-dipping Mine Corridor Volcanics. The tonalite which bounded the western side of the deposit transgresses the domal structure with no apparent interference. A pipe of intense, texturally-destructive, quartz-sericite-chlorite ¦ pyrite underlay and partly surrounded the deposit.The volcanic setting of the deposit, its shape, metal content and associated footwall alteration are consistent with a subsea-floor replacement origin for the gold-copper mineralisation. Mineralogical studies have confirmed the deposit has been recrystallised and annealed by a thermal metamorphic event, most likely the intrusion of the Mount Morgan Tonalite. Pyrrhotite Pipe mineralisation replaces annealed massive pyrite, suggesting that it formed during retrogressive metasomatism associated with tonalite emplacement. Telluride minerals have a close association with chalcopyrite, and no evidence for a late telluride paragenetic stage was observed. Telluride mineralisation is inferred to be genetically related to the massive sulphide mineralisation, and a separate magmatogenic origin for this mineralisation is discounted.

Jan 1, 1993

By Q Liu

Open stoping is one of the widely adopted methods in underground bulk mining. In this method, fanned or parallel holes are often drilled from a top sill down to a sublevel in the ore zone and blasted ring by ring into a stope for excavation. A mass stope blast may involve blasting rock from multi-level drift rounds and displacing the muck to specific locations in order to allow safe and easy access for ore removal. This paper presents a strategic mass stope blast that took place at a large lead and zinc underground mine in eastern Canada. The blast consisted of more than 800 holes drilled in six blocks from three different sublevels. The challenge lay in the control of ground vibration and muck movement using precise timing to complete the blasting within 6.5 seconds. During this time span, sufficient voids were created in each level to allow the muck to move from the upper to the lower levels in sequential order across the six mining blocks without bridging. This paper describes stope blast simulations using a discrete element computer code for modeling blast-induced rock displacement as well as the application of electronic detonators. These detonators provided the means to accomplish the desired firing sequence including a drop raise blast at the start of the mass blast. The modelling concept is also described in the paper.

Jan 1, 2005