Search Documents

This paper discusses support requirements for the proposed monorail system to be used in decline development. The monorail drilling and loading systems are systems that move on the rail (monorail) installed in the roof of the decline and supported by roof bolts, suspension chains and steel supports. However, due to the weight of the components of the two systems, it is imperative that the force in each roof bolt, suspension chain and steel support capable of suspending the weight of the heaviest component is determined. Numerical models that relate the weight of the monorail drilling and loading components to the required strength in the support system have been developed. Using these developed models, numerical values of the forces in each roof bolt, suspension chain and steel support, required to suspend the weight of the heaviest component of the monorail drilling and loading systems are determined.

Dec 6, 2010

By D Pastars, J L. Mauk

Located at the southern end of the Awhitu Peninsula, the Waikato North Head ironsand mine is approximately 50 km southwest of Auckland . The ironsand deposit consists of Quaternary sands, clays and peats, formed by aeolian and marine processes. We sampled on widely- and closely-spaced intervals to test variability within the mining area. X-Ray powder diffraction shows that samples contain feldspars, quartz, pyroxenes, amphiboles, clays and titanomagnetite. Densities range from 1.6 to 2.5 grams/cubic centimetre, with porosities from 30 to 43 percent. The percentage of magnetic minerals values range from 0 to 75 percent, slimes (clay minerals) values of 0 to 26 percent and non-magnetic minerals from 20 to 95 percent. Mineralogical differences in the Mitiwai Formation and Waiuku Blacksand Member cause bimodal populations in the density, magnetic minerals, nonmagnetic minerals and slimes plots. The Mitiwai Formation has higher non-magnetic mineral values and lower density, slimes and magnetic mineral values than the Waiuku Blacksand Member.

Jan 1, 2001

By E Kasai, D Maruoka, Y Konno, T Murakami

The iron ore sintering process produces approximately three per cent of carbon dioxide emission in Japan because a large amount of coke breeze is used as the main agglomeration agent. Therefore, its suppression has been required. A promising method is to replace the coke breeze with biomass char and iron-bearing materials. In this study, the effect of the utilisation of metallic iron with coke or palm kernel shell char (PKS char) as an agglomeration agent on its oxidation behaviour was examined by a series of experiments using a sintering simulator. The use of PKS char leads to a larger decrease in the pressure drop difference of the sintering bed compared to the case using coke. Furthermore, the oxidation rate of metallic iron was larger in the case using PKS char together than that using coke. It was considered that the oxidation of metallic iron was promoted because the bed-temperature increased at a faster rate and achieved a higher temperature.

Nov 8, 2021

The Nena high sulphidation-type copper-gold deposit is composed of andesitic pyroclastic units with minor interstratified lava flows. Epiclastic sandstone and conglomerate, and siliciclastic rocks consisting of mudstone, shale, lithic and bioclastic sandstone and conglomerate are locally present. Pre-mineral diorite intruded and domed the volcano-siliciclastic sequence. Economic copper-gold is hosted by vuggy quartz altered lapilli tuff and tuff breccia. The early hydrothermal alteration stage involved deposition of epithermal banded quartz and chalcedonic silica in localised environments. This alteration stage was locally superimposed by a hydrothermal breccia event. Following the breccia event, magmatically-derived volatiles were channelled through a NW striking dilational fault zone and generated the high sulphidation alteration. The high sulphidation alteration is zoned from a vuggy quartz core with local massive replacement silica through a broad pyritic quartz-alunite halo and finally to a thin illite-smectite zone. This is surrounded by regional chlorite-epidote-smectite alteration. A gangue mineral phase consisting of quartz, alunite and baryte overprinted the zoned high sulphidation alteration and preceded the main copper-gold-arsenic mineralisation. Early sulphide deposition is characterised by marcasite, arsenical pyrite and melnicovenite. Main-stage copper-gold mineralisation involved sequential deposition of hypogene bladed covellite+chalcocite, enargite-luzonite and luzonite+stibioluzonite respectively. The copper sulphides are zoned from bladed covellite-chalcocite in the north (cross-sections 5000 - 5600 N) through enargite-luzonite (cross-sections 4700 - 5000 N) and to luzonite????stibioluzonite in the south (cross-sections 4400 - 4700 N). A late phase of minor acicular covellite and enargite+luzonite overprinted the zoned copper sulphides and associated gold mineralisation. Gold mineralisation commenced at the transition from enargite to luzonite, and continued through the deposition of luzonite-stibioluzonite in both stages. Most gold was deposited during the main-stage mineralisation. Yellow native sulphur was deposited in the remaining vugs and defines the waning stage of the hydrothermal system. Post-mineral dioritic intrusives and feldspar porphyries intruded the volcano-siliciclastic sequence. Finally, supergene chemical processes with associated erosion and uplift generated a 40 - 50 m thick oxide-hosted gold cap. The oxide gold cap is underlain by a 35 - 45 m thick blanket of supergene chalcocite+covellite mineralisation which overlies and occurs throughout the main hypogene copper-gold zone. Supergene gold is related to the distribution of primary gold-bearing sulphides. Therefore, remobilisation and redeposition of gold are considered to be insignificant and very localised.

Jan 1, 1999

The spatial and temporal evolution from the porphyry to high-sulphidation epithermal environment can be assessed by integrating new results on such deposits (Arribas et al, 1995; Hedenquist et al, 1998) with past studies of plutonic and porphyry systems (Dilles and Proffett, 1995; Cline, 1995; Shinohara and Hedenquist, 1997; Hedenquist and Richards, 1998). Some time ago, Sillitoe (1973) argued for the nature of the tops and bottoms of porphyry deposits. He concluded that epithermal deposits may form over the tops of some porphyry systems. We can now conclude more confidently what the tops and bottoms of many high-sulphidation ore deposits appeared like while active (Arribas, 1995; Hedenquist, 1995). In addition, we better understand the nature of the zonation of high-sulphidation epithermal systems from the intrusive to surficial environment (Sillitoe, 1999), and how these two styles of ore deposit are related. Geological and geochemical evidence clearly indicates a continuum between these two ore environments. This improved understanding of genesis allows more efficient exploration for these deposits. There are many examples of spatially associated porphyry and epithermal ore deposits. A genetic connection has been suggested by some, and argued against by others. Nowhere is this spatial association better seen than in northern Luzon, Philippines, where the Lepanto high-sulphidation epithermal Cu-Au deposit overlies the Far Southeast (FSE) porphyry Cu-Au resource (Figure 1). Together these mineralised bodies contain a resource of >3.8 M tonnes Cu and >550 tonnes Au. Lepanto was largely mined out in early-1997. Post-war production until 1995 was 0.73 Mt Cu, 115 t Au and 393 t Ag at an average grade of 2.2 per cent Cu, 3.5 g/t Au and 11 g/t Ag. The recent discovery of the adjacent Victoria low-sulphidation quartz-Au-base metal vein deposit, with a resource of >68 tonnes Au (Cuison et al, 1998), illustrates the variety and abundance of mineralisation in the Mankayan district. This district also hosts the Guinaoang porphyry Cu-Au deposit (Sillitoe and Angeles, 1985) and other epithermal vein occurrences (Figure 1). This brief summary reviews the results recently published on the Lepanto-FSE deposits (Arribas et al, 1995; Mancano and Campbell, 1995; Claveria, 1998; Hedenquist et al, 1998), and stresses the evidence for coupling of mineralisation between the porphyry and high-sulphidation epithermal environments.

Jan 1, 1999

By J Robinson, L D’Uva

"The Gold Fields group and Gekko Systems have successfully worked together on multiple projects, including at the St Ives, Agnew and Granny Smith operations in Western Australia, and the Damang operations in Ghana, with gravity recovery design, technology installation and optimisation the key driver on each occasion.In 2014, Gold Fields Australia identified an opportunity to challenge the historical thinking at Granny Smith and reassessed the benefit of upfront gravity gold recovery. The historical approach had been to employ gravity on the tailings stream of the carbon-in-pulp (CIP) circuit, recovering sulfide minerals into a concentrate from spiral concentrators for further liberation of gold via a regrind circuit.Gekko was engaged to assess the implementation of a gravity circuit within the grinding area, and to perform a comprehensive gravity recoverable gold test program. Test data was fed into the AMIRA P420 BCC Gravity Model to confirm the gravity recovery potential of the ore, and for process design basis generation. Height, space and capital limitations proved to be a design challenge. However, collaborative learnings throughout the project ensured the design and operation of a reliable and economic gravity gold circuit. Ultimately, the Granny Smith gravity circuit was a success, satisfying all the project objectives and yielding consistent, measurable benefits. On average, the gravity circuit recovers 33 per cent of total gold, resulting in an increase to overall gold recovery by 0.7 per cent.This paper highlights the key project drivers for Gold Fields, and the development of the Granny Smith free gold gravity circuit. It details application of test work and modelling, and the challenges and learnings encountered during the design, installation and commissioning stages. This paper seeks to demonstrate that continuous improvement in a long standing operation can be beneficial to overall circuit flexibility and increased ounce production.Citation:D'Uva, L, Robinson, J and Bell, T, 2016. Defying Gravity - Brownfield Continuous Improvement, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 135–144 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By P Allen, E Gleeson, D Boakye, R Chesher, S Konopa

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Not only do epithermal gold deposits provide many challenges in estimating mineral resources, the complexities of these deposits also provide technical challenges in assessing appropriate mining and processing strategies, as well as social and environmental planning and management. The characteristics of epithermal gold deposits include being highly variable with respect to geometry and gold grade distribution, the presence of other economic contributors, mineralogy, texture, rock strength, weathering and alteration overprint. These characteristics influence the economic value of mining projects in an interlinked manner. Consequently, successful exploitation of epithermal deposits requires a holistic approach, coupled with the effective integration of geological data to meet all aspects of mine development decision-making. This paper presents examples of the key technical challenges encountered in estimating and mining epithermal deposits. It also highlights why these issues need to be addressed from the viewpoint of geology, sampling, resource estimation, mine planning, mineral processing and social and environmental planning for the true value of the mining project to be realised.CITATION:Konopa, S, Chesher, R, Gleeson, E, Allen, P and Boakye, D, 2015. Challenges in maximising the value from epithermal gold deposits, in Proceedings PACRIM 2015 Congress, pp 127–132 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By S Natsui, Y Goto, S Kawanishi, J Takahashi, H Nogami

The demand for copper increases yearly, and further improvements in copper smelting efficiency using flash furnaces are required. This study was conducted to understand and promote the interfacial reaction associated with the collision of silica flux and iron oxide particles, ie the formation reaction of fayalite slag, in the reaction shaft of the flash furnace. High-temperature microscopy was used to observe the reaction behaviour of a 2 mm granular SiO2 reagent in contact with micrometreorder- sized FeO reagents in situ. When the amount of FeO was lower than the stoichiometric amount with SiO2, the molten slag formed at the interface between FeO and SiO2 diffused into the SiO2 particle before dissolving the remaining FeO particles. It did not contribute to the subsequent reaction, and despite having the lowest amount of FeO among the samples in this study, many unreacted FeO particles remained on the surface of the samples after testing. On the other hand, under conditions with high FeO content and close to the eutectic composition of the FeO-SiO2 system, a liquid phase formed from low temperatures, gradually increasing in volume and eventually completely dissolving the 2 mm SiO2 grain. These results indicate that the early-stage slag is essential in increasing the interfacial area between FeO and SiO2 and facilitating the supply of FeO to SiO2. In other words, the FeO/SiO2 determines the amount of liquid phase and significantly influences the subsequent interfacial reaction rate between FeO and SiO2. Therefore, the local FeO/SiO2 of the particles falling down the reaction shaft should also be optimised to ensure early slag formation. Meanwhile, the time required for 2 mm SiO2 to complete the reaction for the temperature history employed in this study was significantly longer than the particle residence time in the reaction shaft. Further detailed investigation of the effects of silica flux particle size, composition, and reaction temperature on the reaction time will help find the conditions under which the reaction of silica flux can be completed in the reaction shaft. These kinetic approaches could contribute to future innovations in the copper smelting process using flash furnaces.

Jun 19, 2024

By T Rock

This paper looks at recent advances in the United Kingdom (UK) tunnelling industry with particular reference to the A3 Hindhead Project. A 1.8 km long twin bore tunnel is the centrepiece of the A3 Hindhead scheme, which commenced construction in 2007 and is being delivered under a UK Highways Agency early contractor involvement (ECI) contract. The proposed construction methodology is progressive mechanical excavation of a horseshoe-shaped tunnel with shotcrete installed close behind the face using robotic spraying equipment. The tunnelling medium is a æsoft rockÆ sandstone for which there was little previous tunnelling experience, requiring extensive geotechnical investigations and an innovative approach to lining design. A 240 m long section though sandy material utilising a steel pipe umbrella is also required. This paper describes the development of the tunnel planning and design including the most recent developments in UK road tunnels. The innovative approach to the design of the following is discussed:the æpermanentÆ primary lining,an observational technique allowing optimisation of the steel pipe umbrella design,a plain concrete secondary lining designed for resistance to a hydrocarbon fire, anda spray-applied membrane.

Jan 1, 2008

By R G. Barker, A B. Christie

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. More than 11 Moz of Au and 50 Moz of Ag have been produced from epithermal deposits in New Zealand, almost entirely from 50 deposits in the Hauraki goldfield. Since the 1980s, new deposits have been discovered at Waihi (Favona, Trio, Correnso) and nearby at Golden Cross. Feasibility studies into reopening the Talisman mine at Karangahake are continuing, and advanced projects with preliminary inferred resource estimates are reported at Wharekirauponga, Neavesville and Muirs. In the Taupo Volcanic Zone, 11 prospects have been drilled, resulting in the definition of large but low-grade Au-Ag resources at Ohakuri. In Northland, several Au, Ag and/or Hg prospects are known, and small quantities of Ag and Hg have been mined. Six prospects have had some drilling, with the most advanced exploration at Puhipuhi. The application of Taupo Volcanic Zone geothermal systems research to the modelling of former hydrothermal mineralising processes in some epithermal prospects has enabled better targeting of exploration.CITATION:Christie, A B and Barker, R G, 2015. Exploration for epithermal gold deposits in New Zealand, in Proceedings PACRIM 2015 Congress, pp 533–540 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By B Levasseur, C Olsen, E Ghasemian Langeroudi, F Larachi, F Safizadeh, C Gagnon

Gold recovery by the cyanidation process is often accompanied by the leaching of other species. This leads to the depletion of the level of free cyanide and oxygen available for gold cyanidation. The largest proportion of the consumed cyanide is diverted by the cyanicides (eg S, Cu, Zn, Fe, etc) into non-valuable complexes.COREMÆs Extractive Metallurgy team has been conducting a research program on the improvement of the gold cyanidation process. As a part of this program, the current study aims to investigate the effect of certain operating parameters on the reactions involved during preoxidation and cyanidation. Flotation tailings and single mineral samples such as pyrite, sphalerite and chalcopyrite, along with their different combinations, were analysed to highlight the influence of ore mineralogy on the operating conditions. The effects of different kinds of oxidants (oxygen, hydrogen peroxide, ferricyanide and ozone) and chemical additives (ammonium sulfate) were investigated.Experiments conducted in alkaline solutions reveal that mineralogy is a key parameter since pyrite, chalcopyrite and sphalerite react quite differently during preoxidation and cyanidation. A significant increase in sulfur dissolution, especially on pyrite, was observed by applying preoxidation. H2O2 preoxidation showed a positive effect on increasing sulfate formation, a desirable by-product from the cyanide consumption point of view. Preoxidation of synthetic ores with ferricyanide resulted in boosting thiosulfate formation. Tests conducted on flotation tailings from a polymetallic mine revealed that a short preoxidation increases the dissolution of the ore leading to higher gold recovery and lower cyanide consumption. Regarding the formation of thiocyanate, the most undesirable by-product of the cyanidation, ferricyanide and ozone were found particularly efficient to hinder their formation. Finally, the addition of ammonium sulfate during the cyanidation process showed some promising results in terms of both gold dissolution and cyanide consumption.CITATION:Ghasemian Langeroudi, E, Levasseur, B, Safizadeh, F, Olsen, C, Larachi, F and Gagnon, C, 2013. Optimisation of operating parameters for cyanidation of sulfide-bearing gold flotation tailings in order to prevent the impact of cyanicides, in Proceedings World Gold 2013 , pp 111-120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By A S. Fogliata, L Bengochea, G Mas, J E. Lazarte

The Culampajß auriferous district is located in the northern sector of the eastern edge of the homonymous hill, Catamarca Province, Argentina. Tajo Largo mine is situated in the southern flank of Las Minas gulch at an approximate height of 3.600 m above sea level. In the studied area main outcrops are orthogneiss rocks of Chango Real Formation. The ore mineral is native gold with a lesser amount of pyrite, chalcopyrite, haematite, limonite, malachite, azurite and covellite. These ore mineral assemblages are disseminated in quartz veins filling tension fractures in the host orthogneiss.Several types of inclusions have been recognised, including three phase H2O-CO2liq-CO2vap inclusions, polyphase inclusions with H2O-CO2 and one or more solid phases, and two phase aqueous inclusions. In the three phase H2O-CO2liq-CO2vap inclusions the Tmclath is about 1¦C and the CO2 liquid-vapour homogenisation occurs at 26 - 28¦C, to liquid phase. The homogenisation temperature of H2O-CO2 occurs at 365 - 380¦C in the aqueous phase. This set of data defined a solution with a salinity of 14, 4 wt per cent NaCl equivalent and a density of 0.84 g/cm3. In the two phase aqueous inclusions the melting temperature (Tm) of -5.4¦C and the eutectic point (Te) in -38¦C indicates a salinity of about 7.5 wt per cent NaCl equivalent, with the probable presence of Ca2+. Density of fluid is about 0.83 g/cm3. Homogenisation temperature ranges between 260¦ and 280¦C. The pressure, temperature and salinity of fluids in the polyphase inclusions suggest an early fluid of high density and high salinity. The three-phase fluid inclusions may be the result of an unmixing-phase separation of post magmatic hydrothermal fluid due to pressure decrease along fractures. It is suggested that the deposit was formed during the late magmatic hydrothermal stage genetically linked to granitic rocks and can be comparable with the intrusion-related gold system of Baker (2003).

Jan 1, 2008

By A E. Levett, J Durbin

The environmental, social and governance (ESG) obligations of mining companies promote the consideration of water and land resources as well as the post-mining employment opportunities following the cessation of mining operations. This work aims to outline the potential for a mining operation to use their brackish mine water resources to support microalgae production, generating high-quality organic carbon sources to support their mine rehabilitation and closure outcomes. Microalgae production is an established commercial process for high-value products including vitamins, cosmetics and food supplements. On mine sites, microalgae production offers several major environmental and social opportunities: (i) carbon capture, (ii) metalliferous water treatment, (iii) acid mine drainage prevention, (iv) beneficial reuse of brackish mine water, (v) accelerated soil formation and (vi) post-mining employment (Levett et al, 2023).

Aug 2, 2023

Well designed and maintained haul roads are the key to minimising truck haulage on-road hazards and costs, as well as increasing productivity. However, practically designing and managing a haul road for optimal performance is often diff cult to achieve. Poorly designed and built roads exhibit high rolling resistance - a one per cent increase in road rolling resistance can typically reduce speed on ramp by as much as ten per cent - and on the f at by up to 26 per cent. In the current economic climates, investment and operating decisions come under scrutiny. In the long run, this scrutiny returns improved efficiencies and leaner, healthier operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations - simply by virtue of their contribution to overall cost of operations - often in excess of 50 per cent of total costs for deep open-pit mines. Whilst the end result - improved efficiency and reduced cost per ton hauled - is not in itself problematic, it is the route, or process followed to achieve these savings that needs to be carefully managed. We can be guided on this journey by our understanding of how a road is designed, and, critically, the interplay between a good design and safe, cost efficient haulage.This paper brief y summarises the evolution of mine haul road design, from the seminal USBM work of Kaufman and Ault in 1977, through to current geometric, structural, functional and maintenance management design components. These augmented design and management guidelines have been developed over the past decade, both in response to the requirements of mine operators for more safe and efficient haulage systems, and the truck manufacturers' requirements for a more predictable and controlled operating environment. These developments have been paralleled by the need to minimise haulage hazards, both from a health and safety perspective. Generally, both objectives have been achieved, but with some specific areas of design and operation still presenting ongoing potential health and safety hazards.The paper then summarises current design guidelines for these safety-critical issues, both from a road-design 'best-practice' and road management perspectives. Implementation of the approach is seen as a basis for reducing the potential of an under-designed mine road to lead to health and safety defects and secondly as a means of giving haul road safety and performance issues greater prominence in the minds of the road-user, operator, mine planner and designer alike.

Dec 6, 2010

By E V. Kislov

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Northern Baikal Ni-Cu province is located in Buryatia, south-east Siberia, and geologically is part of the Baikal-Muya volcano-plutonic belt. It is known for numerous PGE-Ni-Cu-bearing mafic-ultramafic intrusions of Neoproterozoic age formed in various geodynamic settings. All these deposits can be regarded as a single Ni-Cu ore cluster located near the Kholodninskoe Pb-Zn deposit, which is ready for mining. In addition, there are less studied, small dyke-like bodies with sulfide mineralisation that formed in a rift setting and may be enriched in Ni, Cu and PGE. Individually, the known bodies are of poor commercial value by their resources, but their close spatial association (<30 km) may make these PGE-Ni-Cu deposits economic in the future. This extended abstract seeks to provide a geological framework of the North Baikal Ni-Cu-PGE province, specifically at the north-eastern Synnyr rift hosting numerous small subvolcanic bodies with Ni-Cu sulfide mineralisation. Some small subvolcanic bodies contain industrial level Ni-Cu deposits (Shanuch, Cabanga-Musongati, Voisey’s Bay, Jinchuan, etc).CITATION:Kislov, E V, 2015. North Baikal region Ni-Cu deposits , in Proceedings PACRIM 2015 Congress, pp 297–302 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The Effect of Using Different Comminution Procedures on the Flotation of Platinum Group Minerals The use of High Pressure Grinding Rollers (HPGR) has been widely reported to have major benefits in the treatment of minerals such as iron ore and diamonds. To date there have been few investigations into its use in the treatment of ores containing Platinum Group Minerals (PGMs). HPGRs are known to reduce energy consumption and wear costs and improve the throughput in the circuit. In the present investigation the effect of the comparative use of HPGR and conventional crushing in combination with either dry or wet rod milling on the flotation of PGMs was studied using batch flotation. Previous studies of a base metal sulfide ores had shown that either HPGR or conventional crushing followed by dry milling produced the highest grades and recoveries. However in the present study it was observed that a similar treatment produced the worst results and the highest grades and recoveries were obtained for the case of conventional crushing in combination with wet milling. The HPGR showed no advantages in terms of flotation performance and dry milling produced particularly poor flotation results. The results were investigated further using various surface characterisation techniques in order to determine the reason for the decrease in grades and recoveries of platinum when using dry milling and HPGR as opposed to the case for base metal sulfides. The feed and product samples were analysed using ToF-SIMS, XPS and MLA. The paper will propose reasons to explain the different flotation behaviour of the two ore types following the various comminution processes focusing on the surface characteristics of the ores, the particle size distribution and the pulp chemistry.

Sep 13, 2010

Analysis of Electrostatic Separation for Rutile Cleaning Duty Using a Plate Electrode Assisted High Tension Roll Separator A plate assisted electrostatic high tension roll separator has been used for the removal of impurity mineral grains from a rutile rich product stream. A laboratory study and a subsequent production study explored the effect of machine conditions with a view to the optimisation of the separation performance of the separator. The performance requirement was that the TiO2 grade in the non-conductor stream was to be less than ten per cent whilst at the same time the ZrO2 grade in the conductor stream had to be less than 0.5 per cent at mass recoveries of greater than 90 per cent to the conductor stream and less than 5 per cent to the non-conductor stream. Mineralogy data was utilized to determine the feasibility of achieving the production targets with the feed under study. Since the feed stream mineralogy was dominated by rutile, leucoxene and zircon, it was possible to use an approximation to the actual mineral assemblage as well as the raw X-ray fluorescence data to understand the separation duty of the Carrara machine. Since there were four conflicting criteria used for the performance requirement, an index was devised that incorporated all the requirements simultaneously. This new index was the sum of the squares of the difference between the achieved and desired values, weighted with respect to the variance of each variable. If the desired value for a particular criterion had been met its contribution to the sum was set to zero, no matter how well the criterion had been met. For the production machine the strict requirements were almost achieved. As expected, the achievement of the target performance was dependent of the feed conditions at the time of measurement. This paper reports the results of this study.

Sep 13, 2010

BATMINÖ, BATMINEÖ, BATMINDÖ are an abbreviation for Business Analysis Tools for Mining, Mine Evaluation and Mine Design respectively. BATMINP are proprietary tools customised to suit individual client requirements. The first suite of tools provides for analysis and evaluation of open pit mining equipment alternatives and includes fleet selection, fleet sizing and production, productivity and economic outcomes. The models address all mine process activities including drilling, blasting, loading, hauling and auxiliary services. All models are built to provide for simultaneous evaluation of multiple alternatives that are time and condition related. Provision is made for modelling from first principles and/or default or shortcut inputs. Sensitivities to key input parameters are easily performed and consistent logic is applied throughout the process. The models are built to provide key outputs in a format suitable for presentation and documentation. Provision is also made in the models for validation of both inputs and outputs through benchmarking, back analysis and budget comparison. The same models can be used for short interval (12 month) planning and control, medium-term (three to five years) and long-term life-of-mine (LOM) planning. Millions of dollars are spent each year on mining plant and equipment. Decisions that impact on the medium and long-term are made. BATMINP tools have been used to perform studies with good results and in most cases the studies have been validated through back analysis and comparing model outcomes to real data.

Dec 6, 2010

Energy Savings and Technology Comparison Using Small Grinding Media Considering the complexity of minerals, the need for finer grinding is increasing along with the energy cost. However, energy is increasing exponentially when grinding finer with conventional grinding balls. The use of small grinding media represents the best potential to improve energy efficiency. Today, it is possible to use grinding media as small as 1 mm. How do they perform in industrial grinding mills? The use of small grinding media (5 - 12 mm), called Millpebs, in regrind mills proved that finer grinding can be achieved at lower energy consumption. In ball mills, energy savings vary from 10 per cent to 40 per cent compared to 25 mm media. A regrind ball mill with a mix of small grinding media can be as energy efficient as an Isa Mill charged with 2.5 and 3.5 mm beads. In vertical stirred mills, energy savings vary from 30 per cent to 60 per cent. To carry out the same final grind, a vertical stirred mill with Millpebs will consume at least 60 per cent less energy than a ball mill using 25 mm grinding media. More potential savings were identified. To achieve those improvements, some operating conditions must be met: 1) feed size should be less than 250 ¦m; 2) the pulp must be fluid enough; 3) finally, the slurry linear velocity should not be excessive. This paper talks about all those industrial results improvement and operating conditions.

Sep 13, 2010

By I M. van Waveren, F Hasibuan, M J. Crow

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Two Hg-Au occurrences west of Bangko, Sumatra occur within the West Sumatra Permian Volcanic Plutonic Arc. The Melipun Hg-Au occurrence was exploited in the past and mineralisation occurs within a hydrothermally altered cupola of a buried intrusion. The Salak Hg-Au occurrence occurs within the outcrop of the Dusunbaru pluton, likely within the remnants of a caldera in which hydrothermal mineralisation was developed. Both occurrences formed late in the history of the volcanic arc, probably between the Triassic and early Jurassic. The Melipun occurrence may have potential at depth, but that at Salak is small and lies within the area of a proposed Geopark.CITATION:Crow, M J, van Waveren, I M and Hasibuan, F, 2015. Two Hg-Au occurrences in the west Sumatra Permian volcanic-plutonic arc west of Bangko in Sumatra, Indonesia , in Proceedings PACRIM 2015 Congress, pp 573–578 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015