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By Gupta A, Fung C. C

The hydrocyclone parameter d5Oc is estimated by the application of Artificial Neural Network (ANN). Results indicate that ANN performs equally well as compared to statically derived analytical formulae. Results also show that ANN will also be convenient in the on-line control of hydrocyclones.

Jan 1, 1996

This paper discusses the implementation and potential limitations of the method for estimating sampling and analytical errors of multiple source mine output blended into a shipping product, described by Everett and Ziegelaar (2010). The practice of quality measurement varies between iron ore miners. The common objective is to monitor effective resource utilisation and control of product quality to customers. A flow diagram is given presenting the various options used by iron ore mine operators and the merits of the different options are discussed.

Mar 1, 2010

Western Australian tin deposits are similar to those of other Precam- brian terrains in that they are mainly associated with rare-metal pegmatites, in which cassiterite is found with minerals containing any or all of the elements Ta, Nb, Be, Li, Cs, Rb and the rare earths.. They differ from Phanerozoic deposits where cassiterite occurs in quartz veins, greisens, dis- seminations in granite or sulphide lodes, and is associated with minerals containing W, Mo, Bi, Sb, As, Ag, or Cu. The main tin production in Western Australia has come from the Pilbara Block where the more important tin- bearing pegmatites are related to a younger granite phase, and from Green- bushes where large albite pegmatites intrude ?Proterozoic metamorphic rocks. The more important tin deposits in the Pilbara Block, and those in the Halls Creek and Murchison Provinces, are related to granites which are richer in Si and K and poorer in Ca, Mg, Fe and Ti than 'average granite'. The tin granites tend to have higher than average contents of Sn, Rb and Li.

Jan 1, 1973

In the process of mining the lower seam in a multi-seam operation, a lot of oblique fract- ures appeared in the upper seam which was in the equilibrium zone. These fractures closed soon after the lower face line passed. Despite the occurrance of some degree of undulations, and and step-like unevenness, the upper seam was subsequently extracted without difficulty. When attempting multi-seam extraction, from the height of the equilibrium zone, the minimum distance between seams in ascending mining should be predicted. By analysing roof con- vergences data and the geometrical configuration of subsidence profile, it was found that the minimum safe distance for ascending multi-seam mining depends on the mining height of the lower seam and the properties and structure of the inter-stratified rocks.

Jan 1, 1986

In classical drill and blast underground mining methods, especially narrow vein operations economic quantities of broken ore can be left behind following normal mucking operations on the stope floors. The ore left behind can have significant economic value and if not collected can be lost forever. This paper reviews techniques for cleaning this material from stopes that have been used in the past and reviews possible modern techniques that can be applied to ensure this valuable material is removed from the stopes.

Aug 1, 2010

Queensland hosts vast deposits of brown and black coal, significant accumulations ranging in age from Permian to early Tertiary. The great diversity of coal resources in the State to some extent reflects the proximity of Queensland to plate-marginal tectonic processes through much of the Phanerozoic eon. Coal is contained within sedimentary basin fills of four fundamental types; 1. extensional, 2. foreland, 3. strike-slip, and 4. intracratonic. Thick (10 m+) though laterally restricted coal bodies are characteristic of extensional and strike-slip basins, whereas coals of more modest thickness but much greater lateral extent are typical of foreland and intracratonic basins.

Jan 1, 1991

By C A. Foss, K Leslie, C Arnold

Magnetic susceptibility measurements provide rapid, non-destructive testing of drill core, but cannot directly map magnetite and/or hematite content. Combined magnetic susceptibility and magnetisation measurements provide much more diagnostic information and, with sparse calibration constraints, are able to quantify magnetite and hematite concentrations and potentially map differences in grain size and texture. We have developed a travelling three-component vector magnetometer that can be run alongside core to map its external magnetic field. The logger has been designed to operate in core sheds and at remote drill sites. It is used to rapidly scan a length of core, with each core being scanned in different rotations. The magnetic field contributions from any remanent magnetisation rotates with the core and cause differences between successive measurements, while the field contributions from any induced magnetisations with isotropic magnetic susceptibility remain constant. Deconvolution of the magnetic field data with simultaneous three-channel inversions of the multirotation data separates remanent and induced components. Interpretation of this data provides estimates of the intensities of induced and remanent magnetisations, the orientation of the remanent magnetisations and the ratios of the induced and remanent magnetisation strengths. We expect these magnetisation parameters to correlate with stratigraphy through a banded-iron formation. Furthermore, we anticipate that we will be able to use this information to map zones of oxidation and other changes along the core. This novel instrument is one component of an integrated CSIRO program to provide new capabilities for iron ore exploration and development based on studies of magnetic fields and magnetisations at scales ranging from centimetres for these core investigations to tens of kilometres for formation studies.CITATION:Foss, C A, Leslie, K and Arnold, C, 2015. Rapid logging of different magnetic phases in banded ironstones using a travelling three-component vector magnetometer, in Proceedings Iron Ore 2015, pp 271–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Anglo American Metallurgical Coal (AAMC) manages five open cut coal mines in Queensland and New South Wales, producing approximately 30 million tonnes per annum. The size and complexity of these mines require efforts by a large and diverse number of personnel to minimise adverse geotechnical events from occurring. To achieve this, the AAMC coal mines in Australia are developing a concept of managing the geotechnical risks associated with open cut coal mines. The overall system utilises a combination of internal training, a management system (operational management systems) and standards, numerical modelling, monitoring, inspections and audits. The development of the standards as well as training and mentoring of exploration personnel, geotechnical engineers, engineering geologists and mining engineers with an interest in the geotechnical aspects of mining, training of the production workforce, mentoring and training of the technical staff create the basis for achieving a pro-active rather than a reactive system. Audits are used to assure that personnel are maintaining the standards and to facilitate cross-mine leanings so that best practices are developed across all sites.

Nov 25, 2010

To reflect on the early history of mining in South Australia requires considerable imagination and rashness. The people who were the chief actors in the scene have long since passed away. Accounts of their activities are hazy and debatable. A broad brush account is all that I can hope to accomplish under these circumstances. It is fitting that a picture be painted and possible lessons learnt from the achievements of our pre- Decessors.

Jan 1, 1987

By S C. Dominy

For any gold deposit-based geometallurgical study, the collection and processing of representative samples for gold grade and recovery tests is critical. Sampling protocols should be designed to suit the style of orebody in question. The proportion and size of gold particles has a direct impact on the effectiveness of sampling protocols and metallurgical recovery processes employed. Studies focussing on ore mineralogy and gold particle deportment, size and distribution are required. Key issues are the presence of gold particle clustering (important for sampling optimisation) and proportion of coarse versus fine to refractory gold. X-ray computed tomography (CT) is a radiographic technique that produces high-resolution 3D computerised models of objects based on density distribution. The ‘virtual’ specimens are made up of voxels, the 3D equivalent of pixels each assigned a grey value based on X-ray absorption. This paper presents the results of recent research on the imaging of in situ gold particles in a coarse gold-bearing ore. The technique shows promise as a rapid non-destructive method for preliminary characterisation to facilitate more detailed studies. Early and rapid gold particle determination enables sampling protocol optimisation and metallurgical recovery parameters to be defined prior to detailed feasibility studies

Sep 5, 2011

By A Fareth

Constructed between 1885 and 1891, the New Croton Aqueduct (NCA) in New York State is a 50 km long (31 mi) brick-lined tunnel conveying water from the Croton watershed north of New York City to distribution systems in the Bronx and Manhattan. Except at two siphons, the aqueduct operates as an open channel conduit from the New Croton Reservoir downstream 39 km (25 mi) to the Jerome Park Reservoir in the Bronx. The remaining 11 km (6 mi) is operated as a pressurised conduit and includes a major siphon, of circular cross-section, under the Harlem River. The aqueduct has a flow capacity of approximately 1100 million litres of water per day (13 m3/s or 290 million gallons per day) and supplies on average ten per cent of New York CityÆs drinking water. The CityÆs water supply system is operated and maintained by the New York City Department of Environmental Protection (NYCDEP). This paper covers the work done during the three main stages of the program to rehabilitate the entire NCA: inspections, design and rehabilitation. It also includes some of the more interesting structural findings of the original construction as well as documents and drawings from the NYCDEP archives. The rehabilitation program has been underway in phases since 1993, with inspections scheduled to minimise outages, allowing this strategic aqueduct to remain in service during critical seasonal periods. The open channel flow section of the aqueduct in the north is horseshoe shaped, with inside dimensions of 4.1 m (13.6 ft) in width and 4 m (13.5 ft) in height. The pressurised section is 3.7 m (12.3 ft) in diameter, and includes a 90 m (330 ft) deep siphon under the Harlem River. A total of 163 million bricks were used in the construction, enough to build a 48 km (30 mi) wall around Manhattan Island, 3 m (10 ft) thick and 15 m (50 ft) high.Between 1993 and 1997 a series of in-tunnel investigations were performed in the open channel portion of the NCA, consisting of field inspection, non-destructive geophysical testing, and coring of the brick liner. Between November 2004 and September 2005, a major inspection program was conducted to assess the condition of the 11 km (6 mi) long pressurised section and all shafts, headhouses and blow-off structures along the entire 50 km (31 mi) alignment. Inspection methods included using an underwater remote operated vehicle (ROV) equipped with sonar and cameras to inspect the deep siphon, fibre optics examinations of probe holes drilled through and beyond the brick lining, and core holes and geophysical inspections to assess properties of the liner and behind-the-liner materials. A water pressure and test grouting program was conducted to assess methods and expected grout takes for the rehabilitation work in the pressurised sections. The rehabilitation program is anticipated to be completed in 2010.

Jan 1, 2008

By Williams DJ

Preliminary calculations suggest that spoil piles in the Bowen Basin will undergo approximately 4 m settlement as the ground water table recovers after mining is abandoned. Approximately 1 m of differential settlement is possible. Superimposed on this will be a long term creep settlement of 1-3 m/log cycle of time. Depending on the nature of the spoil material, partially submerged spoil piles could be sufficiently stable although to ensure stability during long term creep it may be necessary to flatten the final spoil pile face to approximately 25¦.

Jan 1, 1987

Most publicity about the copper industry nowa- days is focused on the adequacy of ore reserves and on excessive mining capacity. These concerns, stemming from public awareness of actual and poten- tial shortages and oversupplies, relate to production rather than consumption. Perhaps the reason for this one-sided view is that copper is thought of as a commodity which is conspicuously traded in world markets, rather than as one of many industrial materials that serve today's rapidly changing tech- nology. Copper differs from other widely traded com- modities in that its real cost of production has pro- gressively increased since World War II. The reasons for the increase are identifiable by analyzing operations in one of the world's large producing centres, the copper province of Arizona. Another respect in which copper differs from some other com- modities is that increases in demand occur less auto- matically in the case of copper than they tend to in commodities whose consumption is more directly related to population growth. The copper industry's current inability to generate and attract needed investment capital is attributable to these differences between copper and other com- modities; it suggests that the concept of copper purely as a commodity is outdated. The key to the problem is better integration between the activities of copper producers and users. Depending on cir- cumstances, integration takes various forms- for example, investment tied to long-term sales con- tracts between producers in developing countries and consumers overseas; common ownership of pro- ducing and manufacturing facilities in industrialized

Jan 1, 1978

By W Zhu, J H. Zhao, H Ma

The permeability coefficient is an essential parameter for the study of seepage flow in fractured rock mass. This paper discusses the feasibility and application value of using readily available RQD (rock quality index) data to estimate mine water inflow and grouting quantity. Firstly, the influence of different fracture frequencies on permeability in a unit area was explored by combining numerical simulation and experiment, and the relationship between fracture frequencies and pressure and flow velocity at the monitoring point in fractured rock mass was obtained. Then, the stochastic function generation program was used to establish the flow analysis model in fractured rock mass to explore the relationship between flow velocity, pressure and analyse the universal law between fracture frequency and permeability. The concepts of fracture width and connectivity are introduced to modify the permeability calculation formula and grouting formula. Finally, based on the on-site grouting water control case study, the rock mass quality index is used to estimate the mine water inflow and the grouting quantity. The results show that it is feasible to estimate the fracture frequency and then calculate the permeability coefficient by RQD. The relationship between fracture frequency and RQD and the relationship between structure surface frequency and permeability follow an exponential function. The calculation results are in good agreement with the field monitoring results, which verifies the rationality of the calculation method. The relationship between the rock mass RQD index and the rock mass permeability established in this paper can be used to invert the mechanical parameters of the rock mass or to evaluate the permeability and safety of the rock mass, which is of great significance to the prediction of mine water inflow and the safety evaluation of water inrush disaster management.

Nov 29, 2022

By Rashleigh C

The selection and application of an effect- ive firing system first require a clear under- standing of the initiating abilities of the com- ponents in such systems. The conditions under which charges can be prematurely initiated by a detonating cord downline must be appreciated. This is a principal consideration in the design of a successful downline/'Anodet'/primer assembly. The advantages and limitations of an electric and several non-electric initiating systems are explained. The factors which in- fluenced selection of the two most suitable systems for use at Isa Mine (viz. downline/ 'Anodet'/primer assemblies and the reinforced long-lead 'Anodet'-type delay system) are dis- cussed. Blasts are detailed in which each of these has been applied. The initiating design for a hypothetical 2 x 106 tonne blast using electric short delay detonators and multi-channel exploders is presented. In this design, charges in remote blastholes are activated after the detonation of earlier firing charges by protecting the firing lines with sandbags.

Jan 1, 1978

By O Dominguez

Significant value can be added to ore supplied from the mine to the mill by measuring its quality in real time and performing grade control additional to that within the mine. Responsibility for ore quality between the mine and mill stockpiles is not always clear due to operational siloes so geologists and mining engineers need to be involved collaboratively with metallurgists to optimise ore value prior to processing. Sensors, such as the GEOSCAN-M which utilises high specification Prompt Gamma Neutron Activation Analysis (PGNAA), that measure conveyed ore flow representatively (continuous and fully penetrative) and in real time have been used in the minerals sector since 2003 and have been successfully applied in multiple commodities. Quality can be measured within the mine where material is conveyed underground or in-pit. Bulk ore sorting is used to divert increments of waste from the ore stream to upgrade material sent to the crushed ore stockpile (COS) as well as to create run-of-mine (ROM) stockpiles of different qualities to maximise blending opportunities and accommodate processing priorities, eg blending out deleterious content. The real time composition measurement can be combined with moisture and fragmentation analysis data for improved ore type characterisation, to control ore blending, for feedback to the mining schedule and block model reconciliation, and feed forward control for grinding and processing operations. The paper discusses various parameters measured and derived in existing operations that are used to maximise coarse waste rejection and metal recovery, optimise plant feed quality consistency, and reduce consumables; power, grinding media, water, reagents, and minimise fine tailings generation. Innovative geometallurgy applications are also discussed.

Mar 22, 2022

By G Pasin, F Wirfiyata, G Khomaeni, W Valery, A Maclean, A Jankovic

The grinding circuit at PT Newmont Nusa Tenggara (PTNNT) – Batu Hijau mine consists of two SABC (semi-autogenous milling, ball milling, pebble crushing) trains, including four 20'?×?33'6? ball mills that have been lined with steel liners since the commissioning of the plant in 1999. During 2011 and 2012 an industrial trial was conducted to evaluate Poly-Met liners (a combination of rubber and steel liners). These new liners were installed in two of the ball mills (ball mills 1 and 2) and operated in parallel with ball mills 3 and 4 with steel liners.The objective of the trial was to compare the plant performance with the Poly-Met and steel ball?mill liners with regards to wear life, mill throughput, grind size and total unit costs. The trial was conducted over the entire life of the liners. The evaluation methodology implemented consisted of frequent spot sampling around the ball mill circuits, complete surveys/audits in both ball mills, and detailed analysis of process data. This paper presents the results of the industrial trial and main conclusions.CITATION:Maclean, A, Wirfiyata, F, Khomaeni, G, Jankovic, A, Pasin, G and Valery, W, 2014. Ball mill Poly-Met liner evaluation at PT Newmont Nusa Tenggara – Batu Hijau mine, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 255–262 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By K J. Riihioja, E Nozawa

SmartTag is a radio frequency identification (RFID) based technology designed to allow tracking of ore from its source through blasting, run-of-mine (ROM) pads, crushers, intermediate stockpiles and finally into the concentrator. This paper presents current developments and the future direction of the SmartTagÖ ore tracking system, as well as presenting some case studies. Successful applications of the SmartTag system have encouraged development to allow the system to be used in a wider variety of plants, in particular plants with finer crushing and screening stages. This presented Metso with a number of technological challenges, including RFID tag and antenna design. By reducing the traditional RFID tag diameter from 60 mm to 20 mm the RFID tags can now successfully pass through a secondary crusher. The new smaller RFID tags (referred to as mini RFID tags) have been used in some Process Integration and Optimisation projects with very promising results. The results indicate that the miniature RFID tags have a higher survivability to blasting and through secondary crushing stages. Extending ore tracking further through the process allows more reliable linking of spatial data with time based process performance. Metso is looking at developing even smaller micro RFID tags, and is also investigating other applications for the SmartTag system, including ore tracking from the original source to the final destination (ie from the mine, through the plant and ports to the customer).

Sep 26, 2011

By Baafi EY, Appiah HK

The Prestea Goldfields Ltd of Ghana, West Africa has produced over 170 t of gold with average grade of 11 g/t since 1912. The deposits occur in a wide shear zone which closely follow the Birimian-Tarkwaian contact. Both the Birimian and Tarkwaian systems are of Precambrian age. Underground exploration is carried out to delineate ore bodies by means of AX size diamond drilling at 50 m sampling intervals. After the orebody has been delineated, development work is carried out by exposing the gold reef. Channel sampling is then carried out at about 3 m intervals in both the stope and stope drives. A channel sample length is commonly 0.6 in, but may vary depending on physical characteristics of the reef. The values of channel samples are linearly combined to obtain the average reef or slope values and/or widths of the exposed sections. The sampling practice and methods of improving the efficacy of sampling at the mine are described.

Jan 1, 1976

By T. Baker

The Eloise Cu-Au deposit is 60 km SE of Cloncurry in NW Queensland and has a current indicated reserve of 3.2 Mt @ 5.8 per cent Cu, 1.5gA Au and I9g/t Ag. It is hosted by metasediments and metabasic rocks that underwent amphibolite facies metamorphism at 550-600¦C and less than 3.5 kb. Peak metamorphism coincided with the regional D2 event which produced an S2 foliation with north-south strike and variable sub-vertical to steep east or west dip. The deposit is associated with several major shear zones parallel to the S2 foliation. The lodes form part of a large alteration system that is localised by the retrograde shear zones. Homblende-biotite-quartz with minor sulphides occur early in the alteration paragenesis which is overprinted by chlorite-muscovite-pyrrhotite-chalcopyrite ¦calcite+¦nagnetite. The later assemblage replaces the earlier Fe-K alteration as well as Fe-rich metamorphic assemblages such as homblende, biotite and staurolite indicating a post peak metamorphism timing for ore formation. Although replacive textures are the most common, the alteration can display open space infill and brecciation as well as durchbewegung and mylonite textures indicating that mineralisation occurred during ongoing ductile deformation. All these features are crosscut by a later brittle phase of calcite-chlorite-quartz¦pyrite alteration.

Jan 1, 1994