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By Armstrong M

Two methods of Monte-Carlo simulations, one suggested by Matheron (1972) and the other by Rudenno (1983), have been tested for simulating coal deposits. To do this 2160 values of ash percentages were simulated using 60 known data points in a two dimensional grid, 20 m x 40 m. 1L is found that while both methods conserve the mean of the known distribution in the results of the simulations, only the first method reproduces the spatial covariance (i.e. the variogram), of the experimental data. The results show that for simulation of regionalized variables only the first method tested yields the desired results.

Jan 1, 1985

Knowledge of the crystal chemistry of carbonate apatites is very important for the development of the concept of biomineralisation and the creation of a scientific base for new biocompatible materials for medical purposes. The present work is devoted to research results on various synthetic and biological carbonate apatites obtained at Saint Petersburg University over many years. All-important problems will be considered such as the location of CO32- ions in the apatite structure, the ionic substitutions in various biological apatites and the development of synthesis methods for their analogues. Syntheses of apatites were realised by precipitation methods and under hydrothermal conditions (from solid compounds and by calcite treatment). Biological samples used in this study were physiogenic and pathogenic apatites formed in the human organism, eg in teeth and in renal and salivary stones and dental calculi as well as apatites from fossils of different taxonomic families (brachiopods, conodonts, fishes, reptiles, mammal) with different geological ages and burial conditions. The study of the crystal chemistry of carbonate apatites has been carried out by powder (including high-temperature measurements) and single-crystal X-ray diffraction methods, IR-spectroscopy, thermal analysis and various chemical analytical techniques.

Jan 1, 2008

Since gold was first discovered, mining development in the West Australian goldfields has been heavily dependent on the location of groundwater both for potable and mineral processing supplies . The location of adequate and economic sources of water has been a constant challenge to both explorers and developers throughout the history of the goldfields. The provision of a piped supply from Mundaring in 1903 greatly alleviated pressure on scarce resources, lowered mining costs and permitted the orderly development of infrastructure. However, increases in the demand for water resulting from new mineral discoveries over the past three decades has led to renewed pressures for more local supplies to be established. Wide-ranging groundwater exploration took place in the late 1960's and early 1970's, also, more recently, in support of intensified gold exploration. The collation and interpretation of the hydrogeological data from the whole goldfields region indicates that despite a low mean annual rainfall of between 180 and 350 mm, quite marked differences exist between the rates of groundwater recharge in different parts of the area, In general, these can be shown to diminish in a southerly direction contrary to a trend towards increases in annual rainfall. Recharge rates are related mainly to differences in rock weathering pattern, geological structure and physiography. The same differences have controlled the pattern of groundwater salinity and the magnitude of groundwater storages associated with the palaeodrainages. In the vicinity of the northern and western watersheds with the Gascoyne, the superficial sediments tend to be thin, may have calcrete in the section and contain moderate storages of brackish or even fresh water. This contrasts with the lower regions of the palaeodrainages where calcrete is absent and deeper erosion has permitted the accumulation of relatively large thicknesses of fine-grained sediments which are saturated with hypersaline water and constitute substantial storages. Account must be taken of these characteristics if water supply sources are to be optimised to meet the growing demands for groundwater in the region.

Jan 1, 1988

By B Xiao, J Yang, H Chen

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Tuwu-Yandong Cu deposit, located in the East Tianshan mountains in the eastern section of the Central Asian Orogenic Belt, is the largest and economically most important porphyry Cu deposit in Xinjiang, China. It contains ~3 Mt of copper at an average grade of 0.46 per cent Cu and 0.2 g/t Au, with significant amounts of Mo and Ag. The deposit is mainly hosted in the Carboniferous Qi’eshan Group and plagiogranite porphyry, and is controlled by faults that are east–west-, north-west- and north-east-trending. Ore minerals in the Tuwu-Yandong deposit are dominated by pyrite, chalcopyrite and molybdenite, with minor bornite, chalcocite, magnetite, sphalerite and galena. Gangue minerals are mainly composed of quartz, sericite, chlorite, epidote, anhydrite, gypsum, muscovite, biotite, phosphorite, sphene, dolomite, actinolite, barite, albite and calcite. Based on the megascopic and microscopic textural relationships and mineral assemblages, five stages of hydrothermal alteration and hypogene mineralisation are recognized in the Tuwu-Yandong Cu deposit: the potassic stage, propylitic stage, phyllic stage, late veins stage and supergene stage. Most of the copper was deposited during the phyllic stage, along with less molybdenite.CITATION:Xiao, B, Chen, H, Wang, Y and Yang, J, 2015. Geology, mineralisation and alteration of the Tuwu-Yandong porphyry Cu deposit, north-west China, in Proceedings PACRIM 2015 Congress, pp 641–644 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By M Field

Kimberlite pipes, as opposed to dykes, sill and secondary deposits, are the primary target for diamond exploration companies because they have simple geometries and can contain large volumes of potentially diamond-bearing ore. Once discovered, important decisions have to be made regarding the sampling of these geological entities to establish the total volume of ore present, and to define the internal geology, which can be complex in nature and controls the distribution of diamond grade. It is essential that as part of this process the uncertainty in constructed geological models are assessed. In this paper the Orapa AK1 kimberlite pipe in Botswana is used as a case study to explore a potential methodology for defining this uncertainty. The uncertainty of the rock volumes of different types can be characterised by a geostatistical approach. Geostatistical simulations, based upon a plausible representation of the geological bodies, provide different possible images of the orebody that can be considered as different realities. By testing different borehole layouts and drilling the orebody virtually on the computer, many different, but equi-probable realisations of the pipes can be produced. It is then possible to estimate the rocksÆ volumes and compare them with the actual ones. A statistical analysis of the relationship between estimation error and the number of boreholes can then be used to optimise the next sampling campaign. The rock volumes are obtained from a two-step simulation process. Firstly, the pipe geometry is simulated by means of introducing variations around the geological block model, by an original method called centre point simulation (CPS), which has been developed for this purpose. Secondly, the internal geology is then simulated within the pipe. The methodology for simulating the internal geological zones has to be adapted to the level of information and to the geological structure itself. The upper portion at Orapa AK1 is filled with sedimentary crater facies. Here plurigaussian simulation techniques can be applied that are adapted to the simulation of sedimentary facies. The central zones of the pipe are typically subvertically-oriented massive volcaniclastic deposits and breccias and the lower regions comprise a complex root zone. CPS is appropriate for these zones.

Jan 1, 2006

By G J. A Dewar

The Australian Corporations Law generally requires Independent Expert Reports to be presented in support of capital raising or in defence of mergers and takeovers. The introduction of the VALMIN Code in 1995 (and its recent revision issued as the VALMIN Code, 1998) made Assessment and Valuation Reports in these circumstances much more comprehensible than before because of its key requirements for transparency and materiality. By forcing the Independent Valuer to provide an explanation of the reasoning behind the estimation of a particular resource asset, VALMIN allows the reader to clearly see any error or illogicality in the valuation methodology used and to seriously question or even reject the resulting value. Even though many elements of resource asset valuation practice are undeniably subjective, there must be some basis of objective rationality to it. Independent resource asset Valuers are the essential link between mineral explorers/miners on the one hand and brokers/analysts/fund managers/investors on the other. The minerals and financial industries both expect them to not use inappropriate or invalid valuation methods and illogical steps within these methods. This paper examines some of the less sensible ways in which some of the main techniques that Valuers commonly use to assess the fair market value of mineral properties have been applied in recent instances. The authors hope to discourage the adoption or perpetration of the æWhat-number-did-you-have-in-mind?' approach. It is MINVALÆs view that as many methods as possible should be used in any resource asset valuation. If any of the resulting estimates are in approximate agreement (particularly if they were derived using the less subjective of the available methods), ie if they cluster, they are probably more persuasive as being the Preferred Value of the asset than outlier values within the Valuation Range.

Jan 1, 1999

By B G. Lottermoser

The placement of sulfidic waste below the groundwater table ensures limited interaction with the hydrosphere and suppression of sulfide oxidation. However, if sulfidic waste is placed above the groundwater table and remains uncovered, the backfill becomes part of the unsaturated zone and is exposed to atmospheric oxygen and leaching. This study aims to establish the leaching behaviour of sulfidic waste placed above the groundwater table and the impact of such leachate on the local aquifer at the Thalanga base metal mine. Mining of the Thalanga copper-lead-zinc deposit resulted in a large final mining void (600 m + 150 m + 70 m) and extensive underground workings. The underground workings were partly filled with tailings and the open pit was partly backfilled with acid producing sulfidic waste rock. In addition, the pit serves as a sink for acidic run-off from adjacent waste rock piles and mine workings. To date, the backfill of sulfidic waste rock placed into the pit has not been capped with benign materials and for most of the dry season, the surface of the backfill is covered by melanterite-type efflorescences. Results of kinetic column leach experiments conducted on the sulfidic waste indicate that Cd, Cu, Zn and SO4 rich waters migrate from the backfilled sulfidic waste into the local unconfined aquifer. However, the seepage of alkaline (pH 7.3 - 8.0), high conductivity (>10 000 ¦S/cm) tailings waters into the remaining pit void clearly shows that the acid leachate originating from the sulfidic waste rock does not impact beyond the waste repository and its immediate environment. Geochemical modelling implies that minimal or no mixing occurs between the acid waste rock leachate and the alkaline tailings waters.

Jan 1, 2003

By Frazer E. J, Lwin T

Measurements of coulombic efficiency (QE) for zinc electrodeposition were carried out under mass-transfer-controlled conditions using a rotating disc electrode in synthetic acidic zinc sulphate solutions. Various methods of solution preparation and purifi- cation were investigated using reagents vary- ing from analytical grade to high purity; the purest solution was obtained-by dissolving 99.9999% zinc (Koch-Light) in sulphuric acid solution (BDH Aristar). Improvements in sol- ution purity did not necessarily increase QE, especially where apparently beneficial impur- ities (e.g., Pb) were initially present. The maximum QE obtainable through variation of temperature (T), current density-(i) and elec- trode rotation rate was established using a statistical optimization technique. The QE was determined principally by T and i, with significant interaction between these factors in the highest purity solution. QE contours, which gave an overall view of solution per- formance, were constructed and predictions about the response under conditions similar to plant practice were made. Wark's Rule (the dependence of QE on zinc/acid ratio) was obeyed in the purest solution over the range of composition commonly encountered in zinc plants. High concentrations of Na2SO4 and K2SO4, which occur in some plant solutions, were found to increase QE marginally ("1.2%). The intrinsic effects of individual impurities such as Cu and Ni were evaluated by additions (up to 5 ppm) to the purest solution. Decreases in QE were found to be minimal at the impurity levels normally encountered in zinc plants.

Jan 1, 1987

The constraints in university courses are lack of hours, high cost of scientific equipment, and poor availability of suitably experienced staff. These have forced the balance away from practical work and towards more theory. Labelling of individuals as either practical, or academic, does not help the inter- change of staff between industry and univer- sities that is necessary to balance idealism and realism. Practical men who do return to universities may lose seniority and find that industry is reluctant to have them back. Academics who specialise too long may concentrate on their research to the exclusion of basic material. It is difficult to operate pilot scale plants in universities because of lack of time, and obsolescent equipment. Small grants from industry might enable tests to be run in research laboratories such as at C.S.I.R.O.. Within universities there may be a need for greater interchange of students among depart- ments, aided by the absence of weighted student unit measurements, as suggested by Aus.I.M.M. and A.M.I.C.

Jan 1, 1984

By R T. A MacGillivray, S B. Curtis

Bacteriophage (phage) are viruses that infect bacteria. Protein coatings on the surface of the phage particle can be genetically engineered so that they bind to inorganic molecules. The filamentous phage particle is about 930 nanometres in length and 6.5 nanometres in diameter and consists of a single-stranded molecule of DNA surrounded by five different coat protein molecules denoted P3, P6, P7, P8 and P9. Peptide sequences in the P3 coat protein that bind to sphalerite and chalcopyrite have been identified. The binding is selective; phage with specific P3 peptide sequences bind to minerals but do not bind to silica or to pyrite. Two peptide sequences in the P8 coat protein that bind selectively to chalcopyrite and pyrite have also been identified. The amino acids in the P8 binding sequences are hydrophilic and thus a coating of a mineral particle with phage having these peptide sequences may render the particle hydrophilic. Experiments are underway to confirm this. Phage are relatively easy to grow and are not living organisms requiring an energy source to maintain life. Phage can also tolerate a range of pH and temperatures. Given this, and the ability to indentify phage coat proteins that bind selectively to a variety of inorganic molecules, phage have the potential to be useful tools in mineral processing and waste treatment.

Jan 1, 2008

By C J. R Hart, J K. Mortensen

The distribution of mineral deposits within northwestern North America (Alaska, Yukon, and northern British Columbia) allows for an in-depth examination of the metallogenic patterns of a growing continental margin. A more complete understanding of the tectonic evolution of this part of the Pacific Rim, achieved over the last 15 to 20 years, now allows for the placement of ore systems into a well-defined plate tectonic framework. Ore deposits older than about 185 Ma represent hydrothermal systems that were active in the platform/shelf environment of ancestral North AmericaÆs miogeocline or hydrothermal systems developed in oceanic arcs and continental fragments more distal to the craton. These include important SEDEX, VMS, and pre-accretionary porphyry deposits. In contrast, most mineral deposits younger than about 185 Ma were formed within the growing Cordilleran orogen, as terranes were accreted to the continental margin during interactions between the North America and Pacific/Farallon/Kula plates. Such syn- to post-accretionary mineralised systems include many large lode gold and porphyry/skarn systems.

Jan 1, 1999

By G Newling

Zinifex Rosebery Mine is a lead-zinc underground mining operation located at the base of Mount Black, on the West Coast of Tasmania. Mining activities at the Rosebery Mine have been undertaken for over 100 years, and it has been operating in its current form for over 60 years. A large surface and underground exploration drilling program over the last 18 months has increased the mineÆs expected mine life from five to 12 years, with expectations that over the next 18 months as the program continues this will swell to 20 plus years. Zinifex Ltd secured Rosebery Mine in April 2004 and commissioned a detailed life-of-mine (LOM) study on all aspects of the operation. One of the most detailed sections of this report was on the state of the current ventilation system. It was identified in this report that for mining at the current depth of approximately 1100 m to continue a minimum 30 per cent increase in ventilation quantity was essential, as well as a likely requirement for a refrigerant cooling plant for each of the two deepest panels, the K and P lenses. It was identified that Zinifex did not have personnel with the expertise in underground refrigeration to manage and implement a project of this nature. A second report was commissioned with Bluhm Burton Engineering (BBE), a South African firm specialising in both surface and underground large-scale refrigeration plants. BBE concluded that two refrigeration plants were required to provide the necessary cooling power in the lower sections of the mine. In 2005, with BBE as technical consultants, Zinifex Rosebery Mine embarked on a project to commission two underground refrigeration units capable of lowering the wet bulb temperature at the decline face by four degrees centigrade. This paper is intended to give the reader an overview of: Rosebery Mine operations,Rosebery underground refrigeration project,technical difficulties associated with implementing an underground refrigeration system, andkey learnings to date.

Jan 1, 2008

By Best R. J, Poulos H. G

The method for design of primary roof support for the large todoidal cavern constructed to house the Sydney Opera House parking station is presented. The cavern was constructed with 5 m of rock cover beneath Sydney's Royal Botanic Gardens. Design of rock reinfonnent using a combination of fully grouted rock dowels and Macalloy bars was based on control of horizontal shear movement along bedding features in the roof. A combination of linear arch type analyses and non-linear jointed finite element analyses were used in the design study together with an analysis of the shear resistance offered by fully grouted bolts under shear deformation.

Jan 1, 1993

The phosphatic overburden of Christmas Island is a lateritic soil and consists dominantly of crandallite and millisite. These minerals are polymorphs of general formula, (Na,K)x Ca2-x (Al, Fe)6 (PO4)4 (OH)10-x (2+x) H2O. Iron occurs only in millisite. Both minerals exhibit similar thermal transformations, dehydroxylating near 600¦C and recrystallizing above 800¦C. Dehydroxylation results in crystal structure collapse but retention of crystal morphology. Ggethite, boehmite and apatite are minor constituents of some-of the phosphatic Soils.

Jan 1, 1971

THE de-silverizing of base bullion at the Port Pirie works is carried out in accordance with the principles of the well-known Parkes process. The base bullion produced by the blast furnace department carries (apart from silver values) impurities, the chief of which are copper, antimony, and arsenic. In order to more clearly indicate the grade of the base bullion, the following analysis, representative of a half-year's production of base bullion, is submitted...Before proceeding with the actual operation of de-silverizing, it is necessary that the impurities, copper, antimony, and arsenic, should be eliminated. This is accomplished in the following steps :- (1) Removal of Coppel - Copper is largely present in the base bullion as dissolved sulphide, and this is removed by liquation in a reverberatory type furnace, of which the following are the essential details :-Working temperature 7500 to 8500 C.Coal consumption per 24 hours 2 tons.The hearth of the furnace is encased in a steel tank 22 ft. 4 in. long by 13 ft. 4 in. wide by 2 ft. 10 in. deep; the bottom of the tank is covered by a depth of composition conforming to the invert :-Cement 39 cwt.Brick dust 8.4 tons.Fireclay 0.6 tons.Sand 0.6 tons...

Jan 1, 1922

By S Hanrahan, S McLaughlin

A case study is presented that details the safety journey at a North American project involving two major contracts: a 1000 m shaft recovery and rehabilitation, and the development of a drainage gallery in a large open pit operation. In the early stages of the contracts, there were a number of incidents that created tension between the owner and contractor, which resulted in the contractor being placed on a final warning with almost imminent potential termination. As a result of this, it was agreed to initiate a focused safety recovery plan as a ‘last chance’.Over a period of two years, the engagement and consequent performance of the contractor was turned around, steadily working to set it up for success such that in one of the contract work areas, a record of ‘one year LTI (lost time injury) free’ was achieved. The journey involved the owner and the contractor teams working cohesively to educate all parties in the safety requirements and, most importantly, providing the context and understanding for certain requirements being put in place. Early on in the process, it was recognised that the owner team unknowingly was an impediment in that they did not fully understand the safety requirements and so was not able to lead the way for the contractor effectively. The journey to rectify the situation was supported and followed up by focused engagement with the project team, which generated a progressive improvement in a very challenging environment.In particular, the contractor turnaround was significant and of enough value for the contractor to ultimately export some of the safety systems from this site to other contract sites. This demonstrated the ultimate benefit of the contractor understanding and buying into a safety culture and system.CITATION:Hanrahan, S and McLaughlin, S, 2016. Winning the safety battle, in Proceedings International Mine Management Conference, pp 181-186 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 22, 2016

By J J. Batchelor, J B. Metson

Titanium (ilmenite) concentrate was extracted from a New Zealandilmeno-magnetite deposit. Tailings from the existing processing line at the Waikato North Head ironsand concentration plant were used as a raw material feed. The titanium bearing mineral extracted was defined as intergrowths of ilmenite and hematite in the size range below 150 um. The Owen-Honda equation was used to determine the conditions forilmenite/hematite magnetic separation. Three distinct regions of magnetic field strength for the mineral separation have been defined. Theoretical estimates from this calculation have been confirmed experimentally. Ilmenite concentrate was obtained using medium field magnetic andelectrostatic separation. The final material contains 40.6 - 42 per cent TiO2 and 39.1 - 39.8 per cent Fe (total). The actual yield from extraction was about seven per cent of the Zircon, leucoxene and monazite were found as byproducts of thetitanium concentration process. Preliminary experiments have shown the viability of industrial zircon benefication.

Jan 1, 2000

By Slater R

The initial planning and detail design phase leading to the development of a 7.5 m internal shaft to service the deep 3000 and 3500 copper orebodies at Mount Isa, Queensland is well advanced. The choice of internal shaft access was made over alternative methods such as a decline from existing levels and borehole hoisting. The resulting access development requirements and shaft configuration for production have been determined. Several techniques are being studied for shaft development. These include the application of blind shaft drilling and large hole reaming methods as well as conventional sinking techniques. As the 3000/3500 Orebodies extend from 1000 metres to more than 1800 metres below the surface, high stress conditions and ground temperatures ranging from 45CC to 62CC are anticipated. The effect of these on the methods being investigated to create a favourable working environment will influence the final choice. Exploration diamond drilling is in progress to confirm the geology of the orebodies so that planning for their extraction including refrigerated ventilation concepts can proceed.

Jan 1, 1982

Laboratory testwork was carried out on an overall orebody composite, of 2.9 per cent Cu and 4.2 per cent Zn, prepared from drill core taken from the Currawong fine-grained, copper-zinc massive sulphide deposit near Benambra in Victoria. While 90 per cent of the copper was readily recovered in a concentrate of 20 per cent Cu, after grinding to 95 per cent passing 38 microns, zinc responded poorly to conventional flowsheet/reagent regimes. Experience elsewhere with the use of reverse cleaning, to separate pyrite from sphalerite, led to a series of tests in which better (but still modest)metallurgical results were obtained. The best result was a zinc recovery of 55 per cent in a concentrate of 50.5 per cent Zn. The major loss of zinc occurred in the reverse cleaning stage where the unit recovery of zinc was similar to pilot plant results achieved at Mount Isa Mines on similar feedstock. Diagnostic mineralogy suggested that an overall zinc recovery of 70 per cent was probably the practical upper limit, at a 50 per cent Zn grade.

Jan 1, 1999

By R Justa Cámara, J María Bertrán Llop

"The need for suitable geotechnical characterisation of the rock mass for underground construction is evident. The enlargement project of Railways of the Generalitat of Catalunya (FGC) in Sabadell is a patent example.In general, it is uncommon to encounter problems in the identification and characterisation of certain relevant weak rock formations, which affect project designs. However, all materials should be properly studied, as mischaracterisation can lead to a suboptimal design, resulting in construction problems during the course of the work.Good quality rock is generally not difficult to characterise, but this is not the case for Quaternary or Tertiary cemented soils. Geotechnical investigations based on boreholes do not provide enough information because samples are often badly damaged during the drilling process, if appropriate techniques are not taken. The samples can be altered and may not be representative of the in situ?material.The design and construction of the extension to the FGC line in Sabadell highlighted the importance of the characterisation of Quaternary and Tertiary cemented soils, in particular their rigidity and its underestimation. The twin tunnel project had a total length of 5.1 km, including five stations with 3.5 km excavated by tunnel boring machine (TBM). The remaining 1.6 km was constructed using cut and cover methods. The TBM portion of the tunnel had a bored diameter of 6.83 m with an internal radius of 3 m and 0.25 m thick precast concrete segments. Much of the tunnel alignment passed through and was affected by the presence of certain stiff layers of Quaternary cohesive materials.In this paper the TBM challenges faced will be discussed in detail. In particular:  TBM excavation rate reductions and overheating problems due to the required excessive thrust and torque floating problems in the lining due to nil earth pressure over the rings and the development of an improved, controlled setting time mortar to address this issue block-in and block-out methodology for each station, in some cases with internal blocks to prevent earth pressure drops and soil scouring the relevance of performing simpler solutions, for example, hyperbaric interventions to examine the cutter wheel tools when it has been shown that interventions under atmospheric conditions were equally feasible the implementation of conventional bivalve machines as standard procedure for excavation of diaphragm walls in stations, where in fact, hydrocutter machines or pile boring machines may have been required, given the mechanical characteristics of the materials to be dug out.CITATION:Justa Cámara, R and María Bertrán Llop, J, 2014. Underground extension of the FGC line in Sabadell through cemented soils, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 161–170 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 17, 2014