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Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-1 and varies widely from place to place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO2 colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed that heating the mud to 500 - 600¦C for 1 hour followed by acid/alkali treatment gave complete recoveries.

Jan 1, 1995

By S M. J Koleini, F Hedjazi

The purpose of this research was to study the calcination of lead-zinc flotation tailings from the Angouran lead and zinc flotation plant in Iran as a pre-concentration step prior to hydrometallurgical processing of the oxidised tailings. There is an abundance of these tailings in the Angouran region and making use of these tailings would help preserve national wealth and also reduce the serious problems of environmental pollution caused by the tailings. At the optimal conditions of calcining at 750 - 800¦C for 45 minutes, the sample showed a mass loss of about 19 per cent. Mineralogical analyses showed that under these conditions the carbonate minerals including smithsonite (ZnCO3), calcite (CaCO3) and dolomite (Ca Mg (CO3)2) decomposed to their respective oxides. Hemimorphite (Zn4Si2O7 (OH)2.H2O) converted into willemite (Zn2SiO4) and this transformation postponed the formation of silica gel in the leach solution. The grade of zinc increased from 22.20 per cent to 29 per cent. These mineralogical changes resulted in desirable reactions in the acid leach process.

Jan 1, 2004

The Mammoth Copper Deposit consists of three distinct orebodies adjacent to the Mammoth Fault. This fault is arcuate, changing from a normal tension fault to a shear strike fault just to the north of the mine. Movement on the fault was probably contemporaneous with deposit- ion of the adjacent sediments. In the upper levels the No. 1 orebody occurs within a brecciated zone in the footwall of the fault, but at depth the No. 2 and 3 orebodies are stratabound by two brecciated lithologic horiz- ons. The host rocks are impure sandstones, arkoces and quartzites, which in the mine area are near the top of the Lower Proterozoic Myally Beds. Overlying these beds is a conglom- erate siltstone sequence which has been assumed to be the base of the Gunpowder Creek Formation. North and south of the mine the conglomerate rests on an erosional unconformity representing a major time break, but in the mine the uncon- formity and conditions of deposition of the conglomerate are obscure. Some mineralization is contained within the conglomerates. The sulphides present are chalcocite, bornite, chalcopyrite and pyrite. Chalcocite is dominant in the upper levels but could be en- riched by supergene processes. At depth, bornite becomes the dominant copper sulphide with lesser amounts of chalcopyrite, pyrite and primary chalcocite. Throughout the orebody minor digenite and covellite occur and arsenic is a minor constituent bound up with the pyrite. The bulk of the sulphides occur in stringers, fractures and breccia interstices but finer grained primary bedded sulphides can be observed. The genesis is probably a complex process in- volving active tectonic movements extending from deposition to post lithification giving numerous phases of brecciation and redistribut- Ion.

Jan 1, 1974

By M.E. Crump

Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-' and varies widely from place to place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO. colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed that heating the mud to 500 -600¦C for 1 hour followed by acid/alkali treatment gave complete recoveries.

Jan 1, 1995

This paper deals with the evolution of present mechanised declining and orebody development practices at Kambalda, since their inception in 1969. Eight separate decline accesses have been established over the past eighteen years and to date some 175 kilometres of declining and lateral development has been achieved utilizing a wide range of mechanised development and mucking units. Improvements in-the range of equipment available, functionalization of the develop- ment tasks and the resultant changes to piecework contract structuring have all contributed to the improved performances achieved in this concept of mine development. Even though numerous development advance rate records have been established at Kambalda, an ongoing evaluation of changes to both drilling and mucking units is underway to further improve these development performance rates.

Jan 1, 1987

By M Zoorabadi

Overcoring is a common technique to measure in situ rock stress using the concept of stress relief. The strains measured during overcoring are used to calculate the stress tensor assuming continuous, homogeneous, isotropic and linear elastic behaviour. This approach does not recognise any effect of the thickness of the rock annulus produced during overcoring instead assuming that the stresses are entirely a function of the difference in strain between the start of the overcoring and the end with no regard to the transient strains produced. Three-dimensional numerical modelling was used to simulate the overcoring process and investigate the impact of core diameter on the transient stresses and strains during overcoring. This study showed that in thicker core, maximum transient axial stresses and strains occur when the drill bit approaches the measuring point and greater tensile axial stresses were produced when the annulus was thinner. CITATION:Zoorabadi, M, 2018. Numerical study of annulus thickness on overcoring stress measurements, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 274–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By D Connelly

The initial results for the cyanide leach gold recoveries were very poor on a high-grade primary sulphide ore of 6.2 g/t Au with no silver. Subsequent mineralogy showed the ore to be a characteristic pyrite, carbonaceous refractory gold ore (double refractory). This was a very disappointing finding. A small scale gravity and flotation test programme was developed to produce a concentrate with the majority of the gold. This also failed with most of the gold remaining in the tailings. An ICP scan also showed variable levels of antimony. A Desktop Study was undertaken with minimal laboratory test work looking at Pressure Oxidation (POX), roasting, ultra-fine grinding, graphite passivation and consideration of any new technologies that might be applicable to this type of ore. The subsequent Study highlighted how difficult these double refractory gold ores are to process and highlighted some recent technology developments may be applicable. CITATION: Connelly, D, 2018. Technology options for processing complex and double refractory gold ore, in Proceedings Complex Orebodies Conference 2018, p 94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By E J. Coyle, L A. Millington

Tailings storage facilities are geotechnically complicated structures that develop heterogeneous strength profiles and varied porewater conditions. The monitoring of porewater pressures is one of the only direct measurements that can be performed to monitor the performance of a facility throughout its life and is of particular importance in upstream facilities. Foundation underdrainage, continuous and staged tailings deposition, climate inputs (rain, snow, humidity, evaporation, etc), and stratified tailings permeabilities can complicate this critical measurement that introduces uncertainty to stability analyses. These difficult conditions manifest in vibrating wire piezometer measurements as very low or negative pressure readings, both of which are within the instrument’s range of accuracy. However, the data can be difficult to interpret, and a range of interpretations are adopted from optimistic low phreatic surfaces to conservative fully saturated tailings. Where tailings are potentially liquefiable, these very low readings introduce further uncertainty regarding the pore space saturation ratio and liquefaction potential above the estimated phreatic surface. This area of uncertainty is the vadose zone, and its affect on tailings behaviour is not well understood. The two facilities analysed in this paper are upstream, raised embankments with tailings classified as clayey, sandy silt that have been found to be potentially liquefiable. The vibrating wire piezometers (VWP) at both sites show very low or negative readings when they are initially installed near the surface and then go through cycles of re-saturation and de-saturation. Eventually the readings settle as the VWPs are buried deeper within the tailings. The instrumented sections within the tailings column do not show consistent readings that would be indicative of a hydrostatic phreatic surface at either site. Rather, they are highly variable and can be interpreted as either representing a high phreatic surface within the tailings or as a ‘perched’ phreatic zone within the tailings layers. How the VWP data is interpreted has a significant impact on how the facilities are raised and operated. The design outcome for Site 1, which adopts a lower phreatic surface, results in an embankment that meets factor of safety (FoS) requirements under residual strength conditions without any buttressing. Conversely, a conservative (high) phreatic surface has been adopted for Site 2 and has resulted in the facility requiring a significant buttress to meet FoS under residual strength conditions.

Jul 1, 2021

By Perry JH, King RL

The Bureau of Mines in cooperation with Kaiser Steel Corporation conducted two methane drainage studies in an advancing section of the Sunnyside No. I Mine where production was being severely hampered by methane emissions. A total of six horizontal aoreholes were completed during the studies to an average length of 291 meters. Total gas production from the boreholes as of December 1981 has exceeded 6,088,800 m3. Methane emissions into the section were reduced by 40 pct as a result of the first drainage system. The second drainage system is currently producing 11,328 m3/day from four Doreholes. Mining of the section and cementing of the horizontal horeholes is expected to begin within 2 Years.

Jan 1, 1982

By N Strong

Cracow is a high-grade; low-tonnage underground gold mine located approximately 500 km north-west of Brisbane in Central Queensland. It is a steeply dipping, narrow vein, epithermal gold and silver deposit that is accessed via a decline from surface. Cracow is owned by joint venture between Newcrest Mining (70 per cent) and Sedimentary Holdings (30 per cent). The orebodies are 5 m wide on average and the ore is extracted via sublevel open bench stoping. Stopes are extracted to a strike of approximately 25 m before being backfilled with waste. Prior to the introduction of electronics, the mine would remove a small amount of the previous backfill out to create a void, and then begin blasting two to three rings at a time, with the ore being extracted between each blast. This method caused the ore to be blasted onto the waste backfill resulting in dilution of the high-grade ore. It also meant that the extraction of each stope took a number of weeks and numerous blasting events. In the fourth quarter of 2005, the mine struck a geotechnically sensitive stope, where all 20 rings had to be extracted in a single shot or risk possible geotechnical problems that could sterilise the ore. Due to the limitations of NONEL« delay detonators the mine could not fire all the rings in a single shot and needed to use an electronic detonator system to extract the stope. Some unexpected benefits to the mine were increased fragmentation, reduced vibrations, reduced dilution, improved efficiency and improved hanging wall and footwall conditions. After the success of this first electronic shot, the mine has since moved to firing all their stopes with electronic detonators. With electronics the mine has been able to fire much larger blasts, and has in fact moved to firing their blasts in the opposite direction, firing towards the draw point instead of into the waste backfill, thus reducing ore dilution.

Jan 1, 2008

By Joussemet R, Fabre F

The paragenesis of the Escuzar Mine (Andalusia-Spain) comprises: ò major constituents: celestite and carbonated minerals (abundant calcite and less frequent strontianite). ò minor constituents: sulphates (gypsum and anhydrite), clays and some iron oxides and hydroxides. The average content is at about 60 per cent SrSO4. Since liberation size was fine (from 30 to 50 ¦m), the flotation method was chosen. Laboratory batch tests have shown the relevance of using alkylsulphates with as long as possible hydrocarbon chains. The recovery obtained led to an expected 95 per cent SrSO4 concentrate with nearly 70 per cent recovery. Pilot plant tests (160 kg/h) have confirmed these results and attained a recovery of more than 65 per cent of a 96 per cent SrSO4 concentrate. Extrapolation to the industrial scale (14 t/h) has been successfully carried out : up to 600 t of a concentrate at more than 95 per cent SrSO4 has been obtained. Non optimised recovery has already reached 60 per cent for a 97 per cent SrSo4 concentrate.

Jan 1, 1993

By Gang L

Seventy-nine gold deposits and prospects have been discoveried in the Jiamusi region of northeast China, and constitute one of the most important gold metallogenic belts in China. All these endogenic gold occurrences can be subdivided into three main deposit types: (1) porphyry related; (2) metamorphic-intrusive hosted, and (3) sediment-hosted deposit. The first two types of gold deposit are spatially and temporally related to Mesozoic Yanshanian granitoid intrusions with hydrothermal activity channelled along crustal-scale fissures. The ultimate cause of the Yanshanian magmatism is considered to be the subduction of Pacific oceanic lithosphere beneath the Eurasian continent. In contrast, The chemical sediment-hosted deposit is typified by the Dongfengshan gold deposit, and genetically related to Proterozoic sedimentation and Mesozoic igneous activities.

Jan 1, 1995

The advent and easy availability of fast and powerful digital computers has marked a transition from one era to another in the field of process control in many industries. Mineral processing is no exception. Aims, practices and problems associated with process control of mineral beneficiation plants in the 'old days' are compared with those available at present. Although basic processes remain generally the same, there have been simultaneous social and economic developments, which directly relate to the development and present value of process control. Lower head grades are now treated, plant capacities have increased, and a large proportion of future capital in the mineral industry will be associated with large capacity plant, treating still lower grades. Environmental considerations have pressurised moves to better control in some areas. With these changes, economic operating incentives have changed, and process control has, in many plants, become more critical. Finally, while computer technology has developed recently at a very rapid rate, developments in the fields of instrumentation, basic on-line measurement and sampling have in general lagged behind, limiting the progress possible in process control. Hence, the benefits of computer control vary depending on

Jan 1, 1977

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

By Schommarz KH, Dunne RC, Goodall CM

Column cells are widely used today for the recovery of base metals by flotation. Their use for the flotation of iron sulphides has not been as rapid. Australia has pioneered the use of large rougher flotation columns. During the last six years, seven rougher columns have been installed on gold mines treating iron sulphides and the technical viability of this technology has been demonstrated. Laboratory column testwork on a gold bearing iron sulphide ore demonstrated the effects of both physical and chemical parameters. In general the large commercial columns operate over a broad range of conditions depending on the downstream treatment of the flotation concentrate. The addition of wash water to commercial columns is not universally applied and there appears to be a need for a better wash water System.

Jan 1, 1993

By S Harrison

Work health and safety duties around Australia include duties to manage psychosocial health and safety (mental health) of workers engaged by businesses or undertakings and of other persons impacted by the operations of the business or undertaking. Persons conducting a businesses or undertakings must develop systems of work and policies and procedures for ensuring, so far as is reasonably practicable, the safety and health of workers and other persons. Officers have a duty to exercise due diligence and to ensure effective systems are developed, implemented and resourced. The developed systems will only be effective with worker’s co-operation and engagement. The duties placed on workers by work health and safety laws are an important part of the safety matrix of obligations. Supervisors and Leaders are workers and they play a critical role in delivering health and safety outcomes. To deliver these health and safety outcomes with respect to psychosocial safety Supervisors and Leaders need to understand their obligations and have a framework to use to assist them in understanding what workers require and what steps need to be taken to meet their duties. They also need to take steps to assist those workers that they supervise to meet their duties.

Apr 16, 2024

PIP is regularly engaged in businesses where Greenfield Capital Projects are under- delivering on the expected business case. In most of these projects, we can identify that rigorous review has been carried out on the design and financial cost elements and substantial reporting is maintained to Boards on progress versus plan of project completion and cost. However, in all sites of this nature that we have worked at, the planning, design and execution of the operational elements or æwiringÆ of the organisation have fallen short and resulted in significant extra cost or opportunity cost (lost tonnage or quality) during start-up. When compared to the amount of planning and resources that have been poured into the capital side, the ledger on the æwiringÆ side is typically fairly sparse. This presentation outlines the importance of running a disciplined, rigorous process to prepare the human and wiring side of a start-up to ensure rapid start-ups and put the site on the pathway to high performance. It gives an outline of the rigorous process PIP has used with projects to ensure excellent start-ups.

Jan 1, 2006

An algorithm is described which leads directly to a unique set of coal washing parameters which, in two or more parallel streams, will give maximum yield of product at a given ash. This occurs when all parallel streams are washed to the same incremental ash. This strategy is shown to offer a considerable increase in yield compared to the simpler strategy of washing each stream to the same sumulative ash.

Jan 1, 1987

By Gao K, Wu C, Langley J. M, Waugh B, Farrell K

The dissolution of carbon from carbonaceous materials into molten iron is a key step in various ironmaking operations. For example, in new direct smelting processes, carbon in the form of coal is injected into the molten iron bath, which leads to the dissolution of carbon. In foundry operations, typical recarburizer materials can range from high purity graphite to chars. The dissolution performance of these" materials is critical to the operation and could dictate the efficiency and economics of the process.Dissolution kinetics has been studied by various investigators to explain the influence of melt conditions and carbon type (Sahajwalla et al, 1994; Shigeno, Tokuda, and Ohtani, 1985; Orsten and Oeters; 1988; Ganguly and Reid, 1992; Wright and Taylor, 1993). The influence of melt sulphur content on the dissolution kinetics has been characterised (Sahajwalla et al, 1994), with sulphur retarding the rate of carbon dissolution. The carbon dissolution from different sources is seen to vary significantly even under similar melt conditions. This observation has been explained by investigators on the basis of the varying ash content present in the carbonaceous materials. However, ash content alone cannot account for the variability in dissolution kinetics reported in other studies. One such study is presented below.In a recent study (Sahajwalla et al, 1994), pulverised carbonaceous materials were injected into the molten iron bath and the" dissolution kinetics was established. The dissolution of graphite and glassy carbon, which contain almost 100 per cent carbon, was seen to be significantly different when the molten iron contained sulphur. The influence of melt sulphur content was explained on the basis of different wetting behaviour observed.Importantly, the study showed that even pure carbon sources dissolved at significantly different rates. Hence, their performance could not be explained on the basis of ash content.The key difference between graphite and glassy carbon is in their atomic structure. Graphite is highly ordered whereas glassy carbon has relatively poor ordering in its atomic structure. This study showed that the atomic structure in carbonaceous materials can have a significant effect on their dissolution performance.The focus of the present investigation which stems from the past study described above (Sahajwalla et al, 1994), is to investigate the influence of atomic structure of carbonaceous materials on their dissolution into Fe-C-S melts.The specific objective of this study is to determine the relationship between dissolution kinetics and crystallographic character of carbon sources. In order to accomplish this goal, a range of different materials representing a spectrum of carbon sources have been chosen for the investigation. These materials include brown coal char, two types of Auscarb (A and B), and commercial graphite. Auscarb is prepared by calcining Auscoal at 1000°C. Auscoal is made from chemically cleaned Australian coals (Bowling, Chandler and Waugh, 1990). Part 1 of this paper details the dissolution performance of the materials studied, while Part 11 describes the X-ray diffraction study. The relationship between the atomic structural dimension and dissolution rate constant is discussed in light of the results obtained.

Jan 1, 1996

By J Emslie

Newmont AustraliaÆs Callie Underground Gold Mine is located on the Dead Bullock Soak Mining Lease, approximately 600 km NW of Alice Springs, NT, in the Granites-Tanami Goldfield. Dead Bullock Soak is part of NewmontÆs Tanami Operations, which also include the Granites Gold Mine and processing plant, Groundrush Open Pit and Tanami Mill. Callie is a world class Proterozoic gold deposit; production to date is in excess of 1.7 million ounces, with an additional Proved and Probable reserves at the end of 2002 of 10.8 Mt at 6.3 g/t. Gold mineralisation at Callie occurs in thin (1 - 30 mm) steeply dipping quartz-chlorite sheeted vein system that cuts across a 40¦ plunging folded sequence of medium to fine-grained metasediments. While the vein system is highly continuous, the gold distribution is highly variable and is controlled by the interaction of lithology, alteration, structure and vein density. The mineralisation is commonly coarse-grained and has a relatively high nugget effect, consequently the orebody is problematic to estimate and shows a high degree of sensitivity to drill hole density. Resource modelling at Callie is an example of a geologically driven model that has evolved with increasing data and understanding. Lithological and structural models are employed to define domains within which the grade estimation is undertaken using multiple indicator kriging. This gradual model evolution impacted greatly on the selection of the mining method. Uncertainty in the estimation of the orebody was a significant factor that led to sublevel open stoping with cemented aggregate fill being adopted as the mining method to improve extraction selectivity. Callie often shows strong positive reconciliation compared to the mill. The mine geologistÆs face the challenge of limiting the degree of underestimation of the core of stopes whilst ensuring that stope boundaries are not conservative. This can only be achieved through the mapping of subtle geological features in order to confirm the orebody model. The increased use of the geological mapping has improved our understanding of the controls on mineralisation and has been extended into the development of new models for near mine underground exploration.

Jan 1, 2003