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By B Mohanty, D Zwaan

Systematic near-field vibration monitoring of stope blasts was carried out in a large, deep underground mine. A total of 31 production blasts were studied in order to investigate the effectiveness of existing blast designs. This involved the vertical retreat mining method, which requires drilling a raise bore or blasting a slot raise (typically 1.22 m in diameter) using large diameter boreholes (165 mm). The diagnostic technique employed multistation near-field monitoring of blasts with high-g (100 g) and high-frequency (>10 kHz) triaxial accelerometers. The amplitude of the vibrations is correlated with the strain energy transmitted from each explosive deck. The results showed that more than 30 per cent of the explosive decks contributed little energy to the rock breakage process in these blasts, and an equal number contributed only inadequately. These findings are indicative of serious blast malfunctions. The problems can be traced to inadequate deck blast design and possibly to drill hole deviation. The various causes for such malfunctions are discussed and remedial measures suggested.CITATION:Mohanty, B and Zwaan, D, 2015. Assessment of underground production blast designs and blasting performance, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 607–616 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By I R. F MacCulloch

Bacterial oxidation of sulfide minerals is a familiar and commercially available process to enhance gold recovery with problem ores. Pintail Systems, a Colorado, USA based company had developed bio-processes for gold recovery based on natural mineral formation and transformation in a global mineral cycle. The biological recovery of precious metals from ore involves a number of mechanisms that are dependent on the metal-mineralogical association. These processes include: partial bio-oxidation of sulfide ores; oxidation of gangue minerals exposing gold to leaching; surfactant properties of bacteria/nutrient solutions that improve wettability of ores and solution contact with leachable gold and silver; and microbial production and excretion of trace amounts of gold lixiviants, and bio-fracturing or biological alteration of ore minerals. Pintail has demonstrated enhanced recovery of precious metals during cyanide detoxification of spent heaps at the end of mine life. Biological recovery processes also have the potential to be applied to in situ mining technologies. The in situ process application could recover gold from subgrade deposits, small deposits or those ore bodies with uneconomic stripping ratios for conventional mining. In situ biomining can be accomplished at a fraction of the cost of conventional mining and leaching and does not have the environmental liabilities associated with many conventional gold lixiviants.

Jan 1, 2004

By F Tang, Ö K. Büyükuslu, M Baben, S Petersen

GTT-Technologies’ ChemApp for Python was developed to provide a powerful, easy to use interface to ChemApp for a programming language highly popular with scientists and engineers. It is used, for instance, by GTT to develop program modules such as the CALPHAD Optimiser for the FactSage™ software, by customers to move from interactive FactSage calculations to perform versatile scripting with Python, and by GTT and its partners in research projects in the area of materials informatics. Computational thermochemistry is fundamental for advancing sustainable metallurgy and creating new alloy compositions for engineering applications. Materials informatics involves handling vast amounts of data and complex workflows. GTT’s approach uses ChemApp for Python and the FactSage thermodynamic databases to design recyclable alloys from the start, incorporating a higher percentage of scraps while aiming to simplify the workflows to simulate material design steps. Challenges arise due to recycling scraps, introducing more elements for consideration. CALPHAD-based databases accurately cover materials from primary metallurgy, but additional data for minority and critical elements is crucial for precise computational modelling. GTT combines machine learning-based ab-initio databases with traditional CALPHAD databases to cover the complete chemical space with appropriate accuracy. The design of a hardfacing alloy through a high-throughput materials informatics approach is used as a demonstrator of the current possibilities.

Jun 19, 2024

By E A. Agorhom, M Beyuo, C Owusu, I Quaicoe

Understanding the mineralogy and liberation of gold particles in an ore is key to the development and optimisation of gold processing operations, being cyanidation or gravity separation. This can be achieved through basic historic geological information, gold deportment studies, chemical speciation and metallurgical test works. The present study assessed the nature of the occurrence of gold particles (mineralogical composition, liberation, associations and surface chemistry) and its effect on the process route (cyanidation and gravity separation) of a typical paleo placer gold ore deposit within the Tarkwaian Rock system. The investigative approach used involved chemical assay, quantitative X-ray diffraction (QXRD) and quantitative evaluation of minerals using scanning electron microscopy (QEMSCAN). The ore samples (A, B, C, D, E, F) used were obtained from six active pits of a gold mine working on this orebody. The results of the mineralogical analysis revealed that the ore is highly oxidised and comprised quartz (>80 per cent) and Muscovite mica (>6 per cent) as the major mineral phases in all the samples. Trace amounts of hematite, kaolinite and todorokite were also identified in all the samples. The chemical analysis showed presence of gold (Au) in all the samples with samples B (3.62 g/t) and C (3.96 g/t) containing the highest concentrations. Trace amounts of copper (Cu), iron (Fe), sulfur (S), aluminium (Al), arsenic (As) were also detected in all the ores. The QEMSCAN mineralogical liberation and gold association results revealed that the gold grains were relatively coarser in all samples (P80 > 80 µm Au in size) except F (P80 < 32 µm Au in size). Gold grains were highly liberated especially in sample B with the majority of the locked gold grains forming complex associations. All the samples responded well to cyanidation and gravity separation except samples C and F, respectively.

Aug 24, 2022

From a personal view that encompasses both research and assessment of major projects the author outlines the two competitive pressures that will force more rather than less metallurgy viz the increasing difficulty in purchasing the latest overseas developments and environmental concerns. This paper then goes on to argue that Australian metallurgy or more precisely process engineering may be in a unique position to deliver the required results.

Jan 1, 1993

By G F. Brent, R D. Hart, C Carr, F Felipe

In underground operations, where copper, gold and other metals are mined, the open stopes can be backfilled to stabilise surrounding workings. This fill may consist of tailings from the processing plant, usually mixed in slurry with a binder such as ordinary Portland cement (OPC). Extensive use is made of tailings in OPC-based paste fill, cemented hydraulic fill or cemented aggregate fill applications. A large underground operation such as the Mount Isa Copper Operations utilises over three million tonnes of backfill per annum. Geopolymers offer an alternative binder system with significant environmental advantages over OPC. Geopolymers are formed by polymerisation of aluminosilicate precursors in an alkali medium. They generally form products with superior strength characteristics as well as increased resistance to degradation, particularly under acidic conditions. Geopolymers have lower carbon dioxide emissions associated with their manufacture than OPC and offer further potential advantages, such as the use of less water and more waste materials. The application of geopolymers to weak material systems such as mine backfill has not been widely studied. The aims of this investigation were to assess a range of Australian mine process wastes for suitability as feedstocks in fill applications and to construct a range of these cemented minefills using a geopolymer binder. The physicochemical characteristics of each of the wastes are discussed as well as how they ultimately contribute to the geopolymer cement through direct replacement of OPC. Results from various tests on the candidate geopolymer fill formulations are presented and the potential of such fill formulations to replace OPC in mine backfilling operations is highlighted. The significant potential contribution to reducing greenhouse gas emissions from the use of geopolymer-based mine backfill across the industry is noted. Conversion of a single mine, such as the Mount Isa Copper Operations, is shown to match the reductions in greenhouse gas emissions due to the current total installed photovoltaic electricity generation capacity of Australia. A similar examination of wastes available to a gold mine could potentially yield new binders for use in established or new fill systems.

Jan 1, 2007

Pilot-Plant Testing of Ammoniacal-Cyanidation for Gold Recovery from Copper Gold-Bearing Ore The results of pilot-plant tested ammoniacal-cyanidation of gold recovery from copper gold-bearing ore are presented in this paper. This ore is from a deposit of Russian Federation with gold and copper grade 9.5&nbsp;g/t and 0.4 per cent, respectively. Copper is largely present as malachite and azurite. The presence of chalcopyrite and bornite is also observed. In order to recover gold, gravity is recommended. Two options of ammoniacal-cyanidation using leaching of gravity tails, CIP and filtration, were tested. It was found that ammoniacal-cyanidation using filtration of leaching tailings and recycled solutions is the most optimal option. The proposed flow sheet provides for 89.7 per cent gold recovery from gravity tailings at the consumption of NaCN 0.9 kg/t and (NH4)2CO3 7.5&nbsp;-&nbsp;9 kg/t. Compared to conventional cyanidation, this technology decreases the consumption of sodium cyanide from 4 up to 0.9 kg/t at the same gold recovery. It can be recommended for the treatment of copper gold-bearing ores with the similar composition.

Sep 13, 2010

By J Wei, A Yo, R Levy

Waste water reuse from municipal and industrial effluents is becoming increasingly important in many areas around the world. Water scarcity, local regulation and environmental impact are driving many industries like coal and copper mines to reuse the large volume of waste water they produce. For example, the Chinese coal industry generated about 4.2 billion tons of mine waste water in 2005 of which only approximately 30 per cent was reused. Coal energy represents 76.6 per cent of the total energy generated in China in 2007 and most of the coal-fired power plants are located in north-west of China, which is a water stressed area.The selection of mine waste water treatment process is challenging as the effluents typically contains high levels of organic compounds and salinity and their composition can vary significantly. In recent years there has been a growing interest in the integration of ultrafiltration (UF) and reverse osmosis (RO) membrane technologies for mine waste water treatment and reuse.In this paper, an overview of the design and performance of ultrafiltration and RO membranes applied for reuse of mine waste water are discussed. A study was carried out in two effluents treatment plants treating copper and coal mine waste water, which are located in Chile and China respectively. The following topics will be discussed to demonstrate the performance of an integrated membrane system in mine waste water reuse: The main challenges from copper mine waste water treatment: high level of chemical oxygen demand (COD); high level of total suspended solids (TSS); high salinity; high concentration of silica, sulfate, iron and other contaminants; and fluctuation of raw water quality. The main challenges from coal mine waste water treatment: high level of total dissolved solids, and waste water quality fluctuation. Design parameters for waste water treatment systems: Selection of pretreatment for dual-membrane system in the copper mine: Clarifier with coagulation and flocculation to remove high TSS; Dissolved Air Flotation (DAF) to remove non-settling solids; Media filtration to handle fine solids and particulate organics; Activated Carbon filters (ACF) to remove dissolved organics, colour and odours. Selection of UF and RO membranes and specific design of their recovery, flux, chemical dosage and cleaning regimes. Finally, the performance of UF and RO, including the main fouling factors and efficient cleaning procedures, will be presented and compared to the design parameters to demonstrate the efficiency and performance of the selected integrated membrane systems in each case.

Jan 1, 2009

Using Mineral Maps to Rank Potential Processing Behaviour

Sep 13, 2010

IN the recent monograph on Broken Hill, N.S.W., by E. C. Andrews,* two independent petrological reports appear as Appendices 1 and n, by W. R. Browne and F. L. Stillwell respectively. In these considerable differences of opinion occur. Andrews contributes to some of the questions at issue, but no analytical review of the differences appears in the body of the report. Their development may invite question, and the following notes have been prepared partly in explanation and partly as a summary of some of the divergences. The soope of Browne&apos;s report extends over the whole district of Broken Hill, while Stillwell&apos;s deals with the rocks within 25 chains of the main lode. The more difficult and important rock-types occur in both areas, raising similar questions. In both cases observations extended beyond the limits of the prescribed areas. Broadly, Browne faces his problem as a study of a series of primary igneous rooks, acid and basio, whioh are intrusive into a series of sillimanite gneisses. The development of the sillimanite gneisses is regarded as belonging to an earlier period than the intrusion of the igneous rooks, while the gneissio structures of the latter are features which are incidental to their orystallization, and are not acquired subsequent to their consolidation. He finally produoes a picture in which his views of igneous injection and differentiation takes a prominent place. One direct result is the claim that three separate periods of metamorphism have oocurred in the Broken Hill area. Stillwell primarily examines the rooks as schists and gneisses since their present dominating features have been acquired during metamorphism. The effort is made to understand suoh differences as might arise from differing conditions of metamorphism upon rocks of similar and different oonstitution. The aim is to divest the rocks of those oharaoters which are due to metamorphism before approaching the questions of intrusive relatio&apos;nships between igneous rocks andsediments.

Jan 1, 1924

Minerals processing needs a step change in energy efficiency. While the search for new technology breakthroughs is important, huge gains are still available by better using existing research outcomes. This potential remains untapped due to a combination of organisational &apos;silos&apos;, inappropriate performance measurement, and poor science in some areas. It is time to see the elephant in the mill.

Sep 13, 2010

By Boyling A

United Collieries Pty Limited is an Australian mining company operating one underground coal mine, United Colliery at Warkworth in the Hunter Valley district of New South Wales. Centrally positioned, United Colliery is adjoined by other coal mining operations and is located 80km north - west of Newcastle and 20 kilometres south - west of Singleton. (Fig. 1) High standard road and rail links provide ready access to customers and suppliers.

Jan 1, 1998

Judicious placement of a range of geotechnical instruments was employed at the Tasmania gold mine, Beaconsfield, Tasmania, as a key strategy in the monitoring of rock mass conditions over the past four years. The range of instruments employed included vibrating wire stress-meters and hollow inclusion cells to monitor changing stress conditions, resistance wire and multipoint borehole extensometers to monitor the impact of stress changes on the integrity of the rock mass, and instrumented cable bolts and threadbar bolts to monitor the static and dynamic impact of rock mass changes on the installed ground control system. Initially the monitoring was of a qualitative nature, monitoring change from the time of installation. The value of the output was considerable when considered in relation to the ongoing seismic record which was also being monitored. It was clear from the seismic record and the monitoring results that stope blasting was the primary trigger for changing rock mass conditions. However, it was unclear how well observed behaviour was reflecting conditions anticipated by elastic numerical modelling. The latter had predicted significant stress increase in the near field of man-access footwall development. Qualitative monitoring and visual inspection did not support the modelling prediction, and this led to a program of quantitative measurement being undertaken. Measurement of the absolute stress condition in the backs of footwall development immediately adjacent to monitoring hollow inclusion cells provided the benchmark for tracking quantitative stress change. The program provided insight into the evolution of principal stress field magnitude and orientation in relation to rock mass change observed with extensometers and instrumented ground control elements, as well as providing a degree of calibration between the elastic numerical modelling and the virgin stress field. Calibrated monitoring data has also provided a useful benchmark for finite element modelling which is to be used for future mine-wide design.

Nov 25, 2010

By J Gresham, A Turichshev

Ore from Henderson’s 7700 Southwest panel cave is transported between the production and truck haulage levels through a series of orepasses. A typical orepass complex consolidates dump points from four production drifts into two long bored raises feeding into a single truckloading chute. The system typically covers a vertical extent of 200 m and a lateral extent of 90 m. In the process of commissioning several initial orepass complexes, challenges with preferential draw in the long bored raises were observed. Preferential draw occurs when one long orepass mobilises much sooner and/or flows significantly faster than the other orepass. This has negative implications for orepass availability in the production drifts. As future mining at Henderson relies on the construction and use of such orepass systems, the development of appropriate design criteria and practical solutions to existing flow problems was necessary.A series of PFC3D numerical models were developed to assist in identifying the factors influencing preferential draw and possible corrective measures. The models helped to identify two primary factors that caused the preferential effect: the relative elevation of the brow at the bottom of each long bored raise, and the location of the bin used to funnel fragmented rock from both raises into the chute. This paper covers the initial design of the orepass complexes at Henderson, results of the numerical models, mitigation work done to date on existing orepass complexes, and design criteria for future construction.CITATION:Gresham, J and Turichshev, A, 2016. Correcting preferential flow problems in long orepass systems at Henderson Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 549–554 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Weber P, Sneyd S

The total world steel production in 1998 amounted to approximately 780 000 000 t. The share of electric steelmaking was in the range of 35 per cent and is expected to increase further to over 40 per cent of the world&apos;s production within the next ten years. As electric steelmaking is primarily based on the use of scrap and as it is progressing more and more into higher steel grades the need for low-residual metallics will become increasingly important. Consequently, the demand for scrap substitute material will increase, reflected in the world wide spate of interest for DRI (Direct Reduced Iron) and HBI (Hot Briquetted Iron). The increased significance of DRI/HBI as a substitute for steel scrap has obviously emanated also from its comparatively lower and more predictable costs per ton and definable chemistry. In 1998 already 37 million tons of DRI/HBI were globally produced.

Jan 1, 1999

By A Batnasan, K Haga, A Shibayama, K Higuchi, H Takeuchi

High silica (SiO2), alumina (Al2O3), and phosphorus (P) contents in iron ore adversely affect the quality of iron products. The removal of those impurities from iron ore is an essential point in further iron ore processing. In this paper, the removal of P, SiO2 and Al2O3 impurities from iron ore by alkaline drying followed by reverse cationic flotation is discussed. The reverse cationic flotation experiments are performed using the iron ore samples without and with alkaline drying pretreatment. All other flotation conditions except pulp pH (4–12) and particle size distributions (-45 to -250 μm) are held constant. A typical collector and frother, such as dodecylamine acetate (DAA) and methylisobutylcarbinol (MIBC), are used in the flotation experiments. Alkaline treatment is conducted before flotation using sodium hydroxide at fixed conditions. The impact of alkaline drying on the performance of iron ore flotation is evaluated based on the removal rates of P and SiO2 + Al2O3, iron grade, and iron recovery compared with the iron ore flotation without alkaline drying (direct flotation). X-ray diffraction (XRD) analysis indicates hematite and goethite are the main minerals in the iron ore, which assays 62.8 mass per cent Fe, 0.232 mass per cent P, 7.1 mass per cent SiO2 + Al2O3 (total) determined by X-ray fluorescence analysis (XRF). Results indicate that a combined approach is more effective for removing P and SiO2 + Al2O3 impurities from iron ore than the direct processing technique because the maximum removal rates of P and SiO2 + Al2O3 are 48.2 per cent and 66.5 per cent from the alkaline dried iron ore when 8.4 per cent and 13.1 per cent from the non-alkaline dried iron ore.

Sep 18, 2023

By M Stewart

The structural framework for the major gold deposits of the Reefton Goldfield was largely established in the 1930s after a detailed regional geological mapping programme. Recent new mapping has now substantially modified the structural framework of the Globe Hill - Devils Creek area and the Waiuta area. Using bedding-cleavage vergence as a method of establishing fold limb facing, many new fold structures have been identified, some of which conflict with long-established structures such as the Globe Hill and Waiuta anticlines. In addition, the mapping of areas of west- versus east-facing limbs constrains the position of many faults. The mineralised Globe-Progress Shear is one such fault which graphically demonstrates major structural discordance of the folds in the hangingwall compared to the footwall. Recognition of the folding is establishing the structural framework for understanding of the origin of these productive gold mining areas.

Jan 1, 1996

By P Landeros, D Benado, J Cornejo, A Pinochet, C Caviedes

In 2005, El Teniente mine began preconditioning the primary rock mass by hydraulic fracturing (HF). The major perceived benefits of this process are a decrease in the magnitude of the expected maximum seismic event and improved cave propagation. In addition, HF has resulted in new information on the propagation pressures of each fracture. Previous studies have attempted to relate propagation pressure to minor principal stress or confining stress.Considering the spatial continuity of propagation pressure and the significant quantity of collected data since the incorporation of the HF technique, minimum requirements for geostatistical modelling have been reached, permitting robust estimates inside the representative volume with acceptable errors (Cornejo, Mu&#241;oz and Rojas, 2012; Cornejo and Landeros, 2013). These results are then used to identify zones with higher magnitudes, which are mostly related to more complex geotechnical zones (intrusive and major faults) and caving singularities, making it possible to estimate the spatial extension of these zones.Finally, these results are integrated with other geomechanics aspects to support risk analysis of the mining plan.CITATION:Cornejo, J, Landeros, P, Benado, D, Caviedes, C and Pinochet, A, 2016. Geostatistical modelling of hydraulic fracturing pressures at El Teniente Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 183–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

Research on Reduction-Magnetic Separation of Bayan Obo Ore

Sep 13, 2010

By Edwards A. B

The following note on the mineral association in the ores of the Tennant Creek Goldfield, Northern Territory, is largely based on Mineragraphic Reports Nos. 49, 89, 117 and 193 of the Council for Scientific and Industrial Research. These reports are the results of the examinations of auriferous specimens from a number of mines of the goldfield and are now supplemented by the examination of further specimens from Mt. Samuel forwarded by Mr. V. G. Martin.The Tennant Creek Goldfield lies in the central portion of the Northern Territory, about Lat. 190 35&apos;, Long. 1340 15&apos;, on the Overland Telegraph Line and about 369 miles north of Alice Springs. It comprise an area extending about 50 miles east and west, by 30 miles north and south.The geology of the goldfield has been described by Woolnough. (2)The rocks of the area are of pre-Cambrian age, and consist of talcose, chloritic, micaceous and siliceous schists of sedimentary origin, interbedded with flows or dykes of schistose quartz porphyry, and of granites which were intruded subsequent to the regional metarporphism of the area. The rocks are moderately folded, but the beclding tends to be obscured by a pronounced east-west cleavage. The most continuous orebodies run east and west, parallel with this cleavage.Numerous lenses of hematite occur in the schists, with their long axes, parallel to the cleavage, and the gold values of the field are frequently associated with such hematite bodies. The dimensions of these hematite bodies are variable but rarely exceed a length of 300 ft., with an average thickness between 10 and 30 ft.; the original vertical dimensions are thought to be comparable with their length. The lenses tend to occur in groups when they are arranged en echelon both horizontally and in depth; and erosion has exposed individual lenses to different degrees, ranging from incipient exposure to complete removal. The existence of unexposed hematite lenses at depth has been proved by geophysical surveys, coupled with drilling tests. (3)A few of the bodies are pipe-like. Many are surrounded by a casing of brecciated rock, composed of fragments of hematite and shattered country rock, and presumably caused by subsequent earth movements which crushed the country rock against the resistant hematite bodies. In the early days of the field most of the important gold occurences were found within these crushed zones, or, to a less extent, within the hematite bodies themselves.These occurrences appeared to be associated only with those hematite lenses which were intersected by quartz veins or other lines of weakness, of later origin than the crushing. This led Woolnough to think that the introduction of the gold and attendant bismuth was subsequent to the...

Jan 1, 1942