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By K H. Esbensen

Sampling of grain, animal feeds (solid and liquid) including important mineral mixtures in the Danish agricultural sector is subject to an ongoing investigation with the objective of improving existing (suboptimal) sampling procedures. Results from the first six months are presented here; the project will continue for two more years and will include international collaborators (Australia and Canada). The Danish authorities have instituted a system of control analysis, which contains a set of mandated sampling and analysis methods. From a preliminary survey it was concluded that in fact all of the existing sampling procedures are not optimised in the light of Pierre GyÆs Theory of Sampling (TOS).

Jan 1, 2005

By C McGuire, W Harris, S Arsenault, D Witow, B Rogers

Mining deep orebodies is increasingly becoming the norm as the ‘easy’ orebodies are depleted. Deep ore mining requires significant ventilation and cooling infrastructure to not only meet regulatory requirements for air quality but also to achieve acceptable workplace temperatures with the higher strata rock temperatures and increased auto-compression. At the same time, advances in battery equipment technology are turning the possibility of a battery powered fleet into reality. The switch from a diesel fleet to a battery powered fleet offers several positive opportunities for the design and operation of a deep mine.The potential to reduce ventilation and cooling requirements due to battery powered equipment results in significant cost savings for mine development and infrastructure. Battery powered fleets are not subject to the same dilution requirements associated with diesel fleets thus allowing lower ventilation rates. At the low ventilation volumes possible with a battery powered fleet, surface refrigeration plants are limited with respect to the amount of cooling that can be delivered to the workface. Considerations for calculating the optimum air flow and cooling requirements are presented. Considerations for locating the refrigeration plant are also discussed. This paper presents these opportunities and considerations; including a case study comparing the ventilation and cooling system design with a diesel fleet versus battery fleet for a planned mine in Northern Ontario, Canada.CITATION:Harris, W, Arsenault, S, McGuire, C, Rogers, B and Witow, D, 2017. Diesel to electric – creating a positive paradigm in underground ventilation and cooling, in Proceedings Australian Mine Vent Conference 2017, pp 169–174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By M J. Davies, R S. Davies

Despite increased expenditure, the global discovery rate of world-class ore deposits has been in decline for over a decade (Schodde, 2017). Mineral exploration has traditionally followed an empirical approach, searching for evidence of mineralisation upon the surface of the planet, then drilling to define the extent of an ore body beneath the surface. As outcropping deposits in well-defined areas are depleted, there is a need for exploration to extend to less well-explored search spaces. One popular new frontier is exploration at greater depths beneath the Earth's surface. However, exploring for deep deposits with limited surficial evidence requires the implementation of predictive targeting methodologies (Hronsky, 2011; McCuaig & Hronsky, 2014). The Mineral Systems Concept (Hronsky & Groves, 2008; McCuaig et al., 2010) provides a framework for predictive exploration targeting. Ore deposit formation is recognised to be a focused mineralising event. These events represent self-organising critical systems and are underpinned by the interaction of complex, non-linear processes. Through the collection and analysis of datasets that map mineralising processes, it may be possible to predict the size and location of resultant ore bodies. CITATION: Davies, M J and Davies, R S, 2018. Beyond below-ground geological complexity: Developing adaptive expertise in exploration decision-making, in Proceedings Complex Orebodies Conference 2018, pp 95–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M Gao, V Lawson, W Valery

Changes in metal prices and mine output over recent years have required the Copper Concentrator of Mount Isa Mines to operate at annual tonnage rates varying from 4.0 million to 6.5 million tonnes. Several circuit combinations were operated during this period utilising up to two semi-autogenous grinding (SAG) mills and up to two ball mills. The aim was to maximise grinding efficiency and keep unit costs constant regardless of throughput rate. Measures to improve the SAG-ball mill unit operation were implemented with each circuit change. These included installation of a splitter to divert SAG Mill cyclone underflow back to the mill, increase SAG ball charge from four per cent v/v to eight per cent v/v, reduce in SAG top feed size and increase of ball mill grinding medium size. Modelling work and surveys led to a new design of the SAG liner profile from 60 rows of rail bar liners in a high-low arrangement to 40 rows of top hat liners in a high-high arrangement. An on-line SAG Mill feed sizing monitor was recently installed to improve grinding control.

Jan 1, 2000

By Yushan Ma, Jiqing Wang, Hanyi Jia

The Hedong Gold Mine is located in the Yantai area, Shandong province, China. It is an underground mine with an annual gold output of some 700 000 grams. The orebody is located on the edge of the Wanger Shan metamorphism zone, and the hangingwall of orebodies is thus defined by a prominent set of fractures. The proximity of the metamorphism zone and the inclusion of the fracture set ensure that both the orebody and the country rocks are unstable. The main orebodies dip at an angle of between 40 to 45¦, with a strike length of 160 metres and a horizontal width of 50 metres. Surface subsidence in the area is not permitted. Cut and fill mining is usually practiced. As the mining operation proceeds to greater depths, the ore grade is diminishing and it is necessary to find a more efficient stoping method. Sublevel open stoping with sequential extraction and filling of each sublevel has been designed and applied in situ. This new mining method is called æsublevel open and fill stoping methodÆ in the mine. Experience to-date is that new mining method is satisfactory.

Jan 1, 1998

By J Johansson, J Lööw

There are many reports about how the new technology will affect our work, sometimes they are utopian but often dystopian. Most of the visions describe the industrial work, while the work of the managers does not seem to be affected. In this article, the authors will discuss how the new technology within the concept of Mining 4.0 changes the conditions for leadership and the work of managers in a modern mining industry.

Sep 1, 2024

By Williams P. A

Tailings dams constructed by the upstream method have traditionally been built using the sand fraction of the tailings, which has automatically provided a relatively permeable embankment material, and helped provide the necessary drainage conditions which are a pre-requisite for safe and stable dam construction using this method. This paper discusses some recent trends which have resulted in proposals to use impermeable material in place of the sand fraction as the embankment material, both for the starter dam, and subsequent lifts. The consequences of these types of decisions on the overall stability of the dam are illustrated, and the need for continued monitoring of pore pressures in the tailings as the dam is raised is emphasised.

Jan 1, 1992

By Salmon P. T, Gilmour R

Commercial production of zinc started at the Pasminco Metals - EZ Plant, Hobart, Tasmania, in 1921. Since that time the capacity of the plant has been steadily increased to its present level of almost 220 000 tpa. Major areas of the plant have been successively upgraded over a number of years, (Roasters, 1969, 1975; Acid Plants, 1981; Casting, 1972; Residue Treatment Plant, 1971), but, until recently, the leach/purification area remained virtually unchanged from the time the plant was built. The major redevelopment of the hydrometallurgical plant began with fully integrated pilot plant testing of the proposed new circuit in 1981. The pilot plant incorporated the Low-contaminant Jarosite Process, and a new two-stage zinc dust purification procedure. In 1985, approval was granted for a major modemisation program which involved the complete replacement of most of the leaching and purification plants, and substantial improvements to the residue treatment plant. Construction of the first of the new plant sections, Strong Acid Leaching, commenced in 1986. This paper describes briefly the modernisation program itself, and the current method of zinc production at the PMEZ plant. The new plant sections comprise a Strong Acid Leach stage to improve lead residue grade; a Preneutralisation stage to reduce metal losses in jarosite; new filtration stages for both jarosite and lead residue; new Neutral Leach and Weak Acid Leach stages to replace old equipment; a new Solution Purification stage to replace the use of organic reagents to remove cobalt; and a new Gypsum Removal stage to cool the solution before electrolysis. At the completion of the modernisation program, only the electrolytic cellhouse remains of the early plant sections.

Jan 1, 1993

By A McRae

Much of western New South Wales is characterised by an extensive regolith formed during more than 60 million years of exposure, weathering and erosion. This cover includes intensely weathered in situ regolith and superimposed transported materials of variable thickness, commonly in complex palaeochannel systems. Mineral exploration in this region has been considerably hampered by the cover, which can complicate or maskgeochemical anomalies and also obscure geophysical signatures. A detailed multi-disciplinary study of part of this region, centred on the Cobar-Girilambone area has demonstrated a methodology for exploring through this regolith. The approach involves regolith-landform mapping to establish the main landscape and palaeolandscape elements and to determine the nature and spatial occurrence of different regolith materials. By combining knowledge of the surface distribution of different regolith-landform units with available 3D information on the regolith and geophysical data it is possible to construct simplified derivative maps or exploration ægoÆ maps, which can be used to advise appropriate exploration strategies or help interpret acquired exploration data. This study has also established the major regolith controls on geochemical dispersion and determined key background element associations. These regolith-related element associations can result in highly variable background levels for many trace elements and need to be understood and factored into the analysis of geochemical data for different regolith sampling media. With better knowledge of the regolith it is possible to select the most appropriate exploration techniques and sampling media for a given area, as well as apply appropriate normalisation procedures to the acquired data. Exploration success can be greatly improved by using many existing techniques in æregolith smartÆways.

Jan 1, 2004

By C A. Locke

Geophysical signatures of the Taranaki and Tongariro volcanoes reflect similarities in their age, composition and hydrothermal histories, but also reflect differences in host rock settings and edifice evolution. The Taranaki volcanoes have strong positive gravity anomalies showing that their edifices largely consist of dense andesite which reflects substantial lava production or dyke injection during construction and that large sub-edifice dyke/stock complexes occur. In contrast, the Tongariro volcanoes have strong negative gravity anomalies indicating low density edifices of volcaniclastic material; no sub-edifice intrusions can be identified, probably because of the lack of density contrast with host basement rocks. Strong positive magnetic anomalies over the younger cones can mainly be attributed to near-surface andesite lavas or dykes whereas subdued magnetic effects are associated with hydrothermally altered zones within both edifices and sub-edifice intrusions.  

Jan 1, 1995

By M Darby, B Burdett, F Lovell

The results of the process control improvement project aimed at improving the quality of Australian Bulk MineralsÆ (ABM) iron ore pellets produced by four vertical shaft furnaces are very positive. These results are achieved through process stabilisation and optimisation, improvement in process monitoring and taking early corrective actions when operating variables were outside the target ranges. A number of benefits are obtained from this project. These benefits include: More consistent and improved pellet quality. The average cold compression strength (CCS) value of pellets produced during the eight-month trial is 260 kg/pellet, which is 16 kg/pellet higher than that produced during the 12 months prior to the trial (244 kg/pellet). Reduction in the heat input by eight per cent, from 727 MJ/tonne to 668 MJ/tonne. Reduction in bentonite rate by six per cent, from 7.1 kg/tonne to 6.7 kg/tonne. Increase in the furnace throughput rate by four per cent and additional production of 10 000 tonnes per annum through process stabilisation. Better understanding of the process behaviour. This knowledge is valuable not only for setting the target operating conditions but also for developing the ABM expert system to control the process.

Jan 1, 2005

Trucks are the primary means of bulk material transport in Open Pit hard rock mines worldwide. They are considered to be the most- flexible system available. The large number of trucks used in some mines provides flexibility. Spare units allow for the reduced availability of the single units. Trucks have however very poor energy efficiency. Only 40% of the consumed energy is for transport of the payload, the remaining energy is required to move the dead load of the trucks. With the increase in cost, pressure, mine operators are now looking for alternative methods to make their operation more economical. Energy conservation and increasing haulage distances and uphill haulage are major factors in many well established operations. New methods have already proven themselves as more economical alternatives. Belt conveyors are an alternative means of transport with much higher energy efficiency. They use up to 80% of the consumed energy for transportation of the payload. Energy costs for conveyors are 30% of the energy costs for trucks on level transport and as little as 15% for elevating payloads. Belt conveyors require much fear spare parts and wear components than trucks. A factor of one to two times applies for level transport and ten to twenty times for uphill transport.

Jan 1, 1986

Through the stress synthesis of many examples of macrostructure in the middle of China, it can be concluded that in the middle of Chinesetectonics there are two compression-torsion-forces, one of which ( from NW to SE ) came from the northwest side of Aerjinshan abyssal and giant fault("F1A", see Fig.7,8,9 ); the other (from S to N ) came from the south side of the north piedmontal fault of Kunlunshan-the south piedmontal fault of Qinlingshan ("F2K-F2Q", see Fig-7,829 ).Owing to the two compression torsion forces a new special type of structure named rotation-apart structure occurred from Chaidamu basin to Hebai, Henan, Anhui plain,from Caledonian movement, Hercynian movement,Yenshan movement to Himalayan movement, step by step In the north of Qilianshan during the late Caledonian movement: during the Hercynian movement it extended into a vast area including the Chaidamu basin and Eerduosi basin; during the Yenshan movement it spread over the whole area of Helanshan,Eerduosi basin and Hebai , Henan, Anhui plain. In the period of Himalayan movement all these structures revived .The rotation-apart structure controlled the distribution of all mineral deposits and also were the mineralizing structures.The relation between these rotation-apart structure and earthquakes is very close.

Jan 1, 1990

The objective in design of an excavation in a jointed rock mass is to achieve a prescribed degree of control of rock mass displacement around the excavation. Any excavation in jointed rock usually involves slip and separation along discontinuities as well as translation and ro- tation of constituent rock blocks. Thus, any acceptable model of behavior around an excava- tion must be capable of simulating the force displacement paths followed by the constituent elements, including rigid body translation and rotation. The distinct element method models such behavior by simulating the rock mass as an assemblage of rock blocks which interact through corner and edge contacts. Discontinuities are regarded as boundary interactions between blocks with joint behavior prescribed for these inter- actions. Introduction of structural element logic allows a variety of installed support sys- tems to be modeled. The response of the support to axial, transverse, and flexural loads is based on explicit algorithms similar to those used in the distinct element formulation. This allows large displacements and rotations and general non-linear constitutive behavior for both the support elements and the interface with the rock. This paper describes both the distinct element and structural element formulations and demonstrates several applications involving sup- port interaction with jointed rock.

Jan 1, 1987

By A Gerdes, H BrStz, E GSbler, D Davis, F Henjes-Kunst, S Dewaele, T Graupner, T Oberthnr, M Sitnikova

Following the United Nations initiative to fingerprint the origin of conflict materials, the German Federal Ministry for Economic Cooperation and Development has decided to fund a pilot study on coltan ores. Since 2006, our working group has been investigating columbite- tantalite (coltan) mineralisation, especially in Africa, also within the wider framework of establishing certified trade chains. More than 300 samples were obtained from the worldÆs major coltan producing areas. Special attention is, however, directed to samples and concentrates from Ta-Nb-Sn provinces in Africa: Democratic Republic of the Congo, Rwanda, Mozambique, Ethiopia and Namibia. Using state of the art analytical tools, we investigate mineralogical and chemical parameters obtained from columbite-tantalite ores and concentrates in order to distinguish between ore provinces, likely even down to the deposit scale. Methods employed include fully automated electron microscopy (mineral liberation analysis), electron microprobe analysis (major and minor elements), laser ablation plasma-source mass spectrometry (trace elements and U-Pb dating), X-ray fluorescence spectroscopy (bulk major and trace elements), X-ray diffraction analysis (mineralogy and structure) and thermal-ionisation mass-spectrometry (U-Pb dating). Major and trace element concentration patterns, mineral assemblages in the ore concentrates, and zoning characteristics in the different pegmatites from Africa distinctly differ from each other. Furthermore, the following age populations are evident:Archaean (>2.6 Ga);Palaeoproterozoic (1.9 - 2.1 Ga);early Neoproterozoic (æKibaranÆ; 0.98 - 0.93 Ga); andlate Neoproterozoic to early Palaeozoic (ca 0.5 Ga). Currently, we focus on the resolution of the fingerprinting system from region via ore province down to deposit scale. Our preliminary analytical results indicate that a certification scheme including fingerprinting of sources of coltan ores is feasible.

Jan 1, 2008

By P Mackenzie, S Askraba

Pyritic black shales present several challenges to mining operations due to their reactivity. The risk of predetonation of explosives in blastholes, spontaneous combustion of fractured rock and the generation of acid rock drainage must be managed for safety, operational and environmental reasons. At the Mt Tom Price iron ore mine there is a need to differentiate between reactive and non-reactive shale in order to assess risk and make decisions on materials handling. The current approach uses a combination of stratigraphic information and sulfur analysis of blasthole samples. The time taken for sulfur analyses can be a constraining factor on mine production. A new instrument developed by ANSTO Minerals overcomes some of the current limitations on material characterisation. The IOR MeterÖ measures the intrinsic oxidation rate (IOR) of samples of broken rock by circulating air through a sample and monitoring the oxygen concentration over time. The intrinsic oxidation rate is given by the rate at which oxygen is consumed per unit mass of sample, in units of kg(oxygen) kg-1(sample) s-1. Up to eight samples can be measured simultaneously and the turn-around time can be less than 12 hours. Initial trials of the IOR MeterÖ were undertaken at the Mt Tom Price mine in July 2004. The measured IOR of samples from a blasthole pattern spanning different geological layers containing black shale, correlated strongly with the expected reactivity of those layers. The correlation between position in the geological sequence (detailed stratigraphy) and IOR MeterÖ results were much stronger than that between stratigraphy and sulfur content. The new characterisation technique offers the prospect of improving the ability to identify and predict the behaviour of reactive black shales and to differentiate more precisely between different materials. Mine planning, operations, safety and environment all stand to benefit from the success of further trials of the technique.

Jan 1, 2005

This paper describes the new legislative regime that will apply to the regulation of the minerals industry in New Zealand.The reform of New Zealands minerals legislation was initiated in January 1988 when the Minister for the Environment, Rt Hon Geoffrey Palmer, announced the Governments intention to review all the major laws governing New Zealands resources. The Resource Management Bill is scheduled for to the House in December 1989 and its date of enactment is scheduled for June 1990.With some matters still to be determined (at the time of writing), this paper cannot be a definitive review and description of the new legislation, it is instead an attempt to outline the major features of the Bill, to date, that are seen as important to the mining industry.

Jan 1, 1990

By Belcher C. B

A simple gravimetric procedure was developed for the rapid determination of carbon dioxide in coal mine roadway dust samples and the result is used for the subsequent calculation of incombustible matter contentaccording to the requirements of the Queensland Coal Mining Act. The carbon dioxide is determined through loss of mass by a semi-enclosed apparatus, following room-temper.ature hydrochloric acid attack on the sample.With a sample containing 36 per cent carbon dioxide, the achieved standard deviation (ls) of 0·3 per cent CO. is adequate for coal mine roadway dust analysis.This simple procedure enables relatively unskilled labour in mine laboratories, to analyze coal mine roadway dust samples in accordance with the Act. Some 50 analyses can be achieved per day compared with 8 by the Australian Standard Method for coal.

Jan 1, 1976

This report chronicles the historical development of longwall mining in the United States and speculates on future developments to the turn of the century. Five eras of technological development during the modern period are described and analyzed. These eras discuss the development of (1) mechanized extraction, (2) self advancing roof supports, (3) high capacity roof supports, (4) shield supports, and (5) system automation. Current trends are analyzed in terms of: longwall utilization, production capability, support capacity, face widths, and new technological developments. From these analyses, the future of longwall mining to the year 2000 is speculated. It is concluded that longwall mining will continue to grow in importance during the next decade and that the next major technological milestone will be the realization of a fully automated longwall mining system.

Jan 1, 1992

By Williams D. J

The boundary element method is one of a number of tools that have found wide application in geomechanics for mine design and stress analysis. Two examples are presented in this paper, illustrating the use of the boundary element method to find potential problem regions in large-scale excavations. These examples are from a Papua New Guinea open cut mine and an Australian sub-level caving operation. Because of the scale of the mines and the complexity of the excavations, the boundary element method is the only practical numerical modelling technique to account for the major influences. Although the boundary element method uses only linear elastic models of the rock mass, the paper illustrates techniques for dealing with non-homogenous and anisotropic rock masses, as well as clasto-plastic effects associated with an excavation.

Jan 1, 1995