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The Maddingley brown coal seam at Bacchus Marsh, where mined and bored, tends on the whole to a higher content of volatile matter than the Latrobe Valley brown coals, and this masks the presence of lignitic or earthy coal bands in the bore core analyses. Visits to the Lucifer Open Cut, at Bacchus Marsh, during 1948, revealed, however, a banded condition in the coal seam, as shown in Fig. 1. This banding showed in a face that had been exposed for a considerable period of time, permitting partial drying out and oxidation of the surface coal. The bands consist of different coal types, ,comparable with those found in the Yallournand Latrobe brown coal seams(l).The' light coloured bands in Fig. 1 consist of a buff to light-brown earthy coal of low specific gravity, that closely resembles the pollen coal, that occurs, as similar thin bands in the Yallourn and Latrobe seams. The 40 ft. of coal above the uppermost of these light coloured bands dries out on exposure to a black, closely cracked surface, composed of small dice-like fragments of a lustrous vitrain-like substance, and in every respect resembles the lignitic coal bands of the Yallourn and Latrobe seams.The coal between and below the light-coloured bands develops fewer and more widely spaced shrinkage cracks on drying out, and remains brown in colour and earthy in appearance, resembling the earthy coal of the Yallourn and Latrobe seams.Representative samples were cut of these coals, taking care to exclude surface coal, and analyses were made of them by the Metropolitan Gas Company, through the kindness of Dr. R. S. Andrews, Chief Chemist to the Company...

Jan 1, 1948

By C Jones

Ridgeway Deeps is a block cave (BC) located down dip of the operating Ridgeway sublevel cave (SLC) mine. The BC is located approximately 210 m vertically below the lowest SLC level and approximately 1100 m below surface. Due to the mine layout containing a number of common pieces of key infrastructure the activities of both were interlinked.When investigating project construction options for the BC, a number of potential risks were identified including a conflict of priorities between operational and project deliverables and the varying safety and work methods between an owner mining approach in the SLC and a potential contractor workforce in the BC. This led to a review of the construction philosophy and the opportunity to utilise the existing SLC workforce as the basis of all activities in the mine. It was identified that a number of synergies existed with the current SLC operators and mine supervision including common work practices and the opportunity to build on the unique SLC skills of the operators and supervisors which could then be used at other Newcrest caving mines.With the commitment to this philosophy of building on the existing SLC crews and supervision the number of employees reporting through the superintendent underground operations grew from 95 to 245. This increase led to a restructuring of the reporting and work requirements of the superintendent, foremen and shift bosses. In order for the foreman and shift bosses to focus on running the larger crew numbers for the full 12 hour shift the mine superintendent became a pseudo human resources manager taking over all non-mine focused activities including overtime allocation and work and behavioural performance management. In simple terms, ensuring there were competent bums on seats when and where required. As the additional workers were recruited to top up the existing employee numbers, their employment history was used to place them in the most suitable roles. For example, those with building industry experience were placed on the civil construction crews and those with a farming background were used as truck drivers, nippers or on the service crews. To cope with the increased number of new starters a number of key personnel were seconded from the crews into the training group to act as on shift trainers. This initially caused a reduction in mine performance as the main operators were reassigned but it proved a valid move as the time for new operators to reach acceptable levels was significantly reduced with safe operating standards being maintained. This paper discusses how the Ridgeway Deeps Project was delivered on time and under budget whilst at the same time retaining its position globally as an operation to be benchmarked against.

Mar 21, 2011

By A C. Chieregati, A Heberle, F L. S P Villanova

Since the publications of Gy’s initial work, many authors have discussed the approaches to estimate the variance of the fundamental sampling error (FSE). Experimental tests suggested by Pitard and François-Bongarçon determine the sampling parameters K and a to calibrate Gy’s formula. The heterogeneity test and the sample tree method are well known and broadly used for many commodities. However, prior to the analysis, the collection of a representative sample is an intriguingly difficult task. The composite for the heterogeneity tests often consists of run-?of-?mine material or processed ore on a conveyor belt. In most cases the final sample does not have enough mass, mixes different geological units, represents a rare blend and does not characterise the deposit. In order to obtain a reliable composite for trace elements and low-grade ores, sampling practitioners suggest at least half a ton of material.To prevent the common representative pitfalls in the FSE, this case study focuses on a single gold-?bearing geological unit collected in situ. With this unit being structured by the mine geologists, but with the interaction between engineers and chemists, it was possible to validate the reconciliation suggested by Pitard (2015). The heterogeneity test and the sample tree method were performed using 500 kg of a smoky quartz from a single geological domain and the results were compared to Gy’s formula. The logging practice by the geologists was modified, emphasising the definition of the size of the gold nugget or its cluster, number of grains and association. Finally, a mineralogical study was conducted on the geological unit to define the liberation factor. All the information is compiled in this paper, showing the need to fully understand the mineralisation to correctly define representative samples and proper analytical techniques.CITATION:Villanova, F L S P, Heberle, A and Chieregati, A C, 2017. Heterogeneity tests and core logging – a final reconciliation, in Proceedings Eighth World Conference on Sampling and Blending , pp 107–114 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Commissioning is one of the many phases of a project, it has inter-dependencies with the other phases, as they have amongst themselves, and has its own terminology and distinctive features. Commissioning time and cost can severely affect project economics, especially through unrealistic estimating, and requires a separate management team to ensure full control is. maintained. Targets to be achieved in commissioning are identified, together with the necessary policies to achieve them. Factors which have to be taken into account in applying these policies are Discussed.

Jan 1, 1986

By K Faure

At Sams Creek a gold-bearing, peralkaline granite pophyry dyke intrudes Ordovician-Silurian metapelite and quartzite. The granite porphyry dyke has a thickness of up to 40 m, extends discontinuously for about 8 km, and intrudes thin lamprophyre dykes along its contacts. The granite dyke and gold-bearing sulphide and quartz-siderite veins within it have been deformed and recrystallised during several phases of folding, the youngest of which is Early Cretaceous.   The unaltered granite porphyry is composed of phenocrysts of perthite, arfvedsonite, aegerine and quartz in a groundmass of the same minerals, with accessory ilmenite, rutile and fluorite. K-Ar dates of amphibole from the granite gave ages of 226 and 246 Ma, but these ages may be a minimum due to resetting during the thermal and deformation events that have affected the area. Unpublished Ar-Ar data on amphibole from the granite show disturbed spectra with high temperature steps around 300-315 Ma, which is consistent with the age of A-type granites in the Buller region. Further age dating of primary and hydrothermal minerals in the granite is continuing. At least three stages of hydrothermal alteration have been identified in the granite. Stage I alteration is characterised by high fO2 magnetite-siderite ¦ biotite, which is cut by thin quartz-pyrite veinlets (Stage II). These are cut by Stage III sulphide, quartz and siderite veins, and pervasive silicification represented by quartz-perthite-albite-rutile ¦ pyrite-siderite-sericite assemblages overprints the earlier alteration stages. Lamprophyre is altered to a siderite-chlorite-sericite assemblage. Stage III sulphide veins are composed of arsenopyrite + pyrite ¦ gold ¦ galena ¦ sphalerite ¦ chalcopyrite ¦ pyrrhotite ¦ graphite, deposited by low fO2 H2S fluids. The gold contains 18-30 wt% Ag and up to 1 wt% Bi. Temperature of vein formation was estimated from vein quartz fluid inclusion homogenisation temperatures (Th 260-355oC, average 330oC), arsenopyrite-sphalerite thermometry (310-365oC) and quartz-albite stable isotope thermometry (340oC). The altered granite and the veins have been deformed, and recrystallised and competent sulphide minerals are fractured and brecciated. Alteration and mineralisation are confined to the granite porphyry and adjacent lamprophyre.

Jan 1, 2004

By R Winterberg

Concrete is a well established and reliable construction material for the permanent lining of tunnels, but shows some weak performance characteristics, which can be overcome by the addition of specialised fibre reinforcement. This paper addresses the particular performance design requirements of segmental linings, discussing the improvements of fi bres on concrete properties. Focus is made on the beneficial effects of fibre reinforcement on the cracking behaviour and the toughness performance, providing a safe and durable tunnel lining.Not only the mechanical performance of fibre reinforced concrete (FRC) for segmental linings, but also the durability of the linings has gained growing attention among the designers and consultants. Especially tunnel linings with exposure to media with corrosion potential, such as wastewater sewer tunnels or desalination plant outfall tunnels, have high requirements on their durability. The design of these structures must provide a comprehensive study of durability aspects. Fibre reinforcement can substantially improve the durability of concrete.Research has been carried out on the cracking behaviour of concrete. The beneficial effects of steel fibres on the cracking behaviour reduce the permeability by reducing the flow paths within the concrete. Crack bridging steel fibres create necking effects in bending cracks, leading to earlier closure of the cracks. Further, steel fibres create particular crack formations, which lead to a substantial reduction of the fl ow rates through separation cracks. The results also show that considerable cost savings can be achieved using FRC, as the thickness of the linings can be reduced.The durability design issues will be addressed and underlined by a case history on the Hobson Bay sewer tunnel in Auckland, New Zealand.

Mar 8, 2011

By M Norbert, C Bennett

The Legacy Way Tunnel was constructed from Toowong to Kelvin Grove in Brisbane, and is the first large-scale underground excavation in the Bunya Phyllite in Brisbane. The Legacy Way Tunnel is 4.3 km in length, comprising two mainline tunnels excavated by a tunnel boring machine (TBM) with 46 connecting passages excavated between the mainline tunnels for egress provision and services. The Legacy Way Tunnel passes through two geological formations, the Bunya Phyllite and the Neranleigh Fernvale Beds. The Bunya Phyllite is the dominant formation of the Legacy Way Tunnel, extending for three quarters of the tunnel prior to intersecting the Normanby Fault Zone (NFZ) and the Neranleigh Fernvale Beds. The NFZ forms the contact between the two formations as part of the Brisbane Metamorphics, which underlies the majority of Brisbane City. The development of the geological model and the understanding of the ground’s reaction to tunnelling was an iterative process. The tender phase investigation data has been supplemented with additional design phase investigation boreholes, geophysics and walk overs. Aerial photograph interpretation coupled with borehole data allowed the development of the domains along the length of the tunnel. Early excavations for the spoil conveyor tunnel and borehole data from subsurface instrumentation installation provided the first construction phase data followed by the commencement of tunnel boring machine (TBM) excavation. Routine cutterhead inspections coupled with ongoing reviews of the predicted geology resulted in clear response triggers to selection of segment types while detailed inspections in passage locations provide the initial classifications for segment removals.CITATION:Bennett, C and Norbert, M, 2014. Tunnelling within the Bunya Phyllite of Legacy Way, Brisbane, Queensland, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 131–140 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Durucan S

The southern Attiki peninsula is a very interesting area from an environmental point of view. The port and the city of Lavrio is situated at the east coast of the peninsula with about 10 000 inhabitants and there are also a few villages in the vicinity. The south-eastern part of the peninsula hosts the famous Lavrio mines which exploited the silver bearing orebodies of the area for more than 25 centuries. As a result, soils around the city of Lavrio are polluted with high heavy metal loads. The area is also of archaeological interest, as there are well preserved remnants of ancient mining and processing plants and archaeological sites. Soil samples collected from an area of approximately 120 km2 around Lavrio were analysed for their metal contents and the spatial distribution of the concentrations of ten selected elements were estimated from these data sets. The spatial data analysis and transformation capabilities of Geographic Information Systems, combined with extensive mining and geological data, helped the authors to identify the extent and causes of metal pollution around Lavrio.

Jan 1, 1995

By Fejes A. J

The U.S. Bureau of Mines installed surface and subsurface instruments at a mine site in Colorado to monitor and characterize the overburden response to longwall mining. Instrumentation included a time-domain reflectometry (TDR) cable, a multiple-point borehole extensometer (MPBX), vertical- deformation surface monuments, and in-mine pressure cells for monitoring abutment, pillar, and gob loads with respect to the longwall face position. The purpose of the study was to collect data that could be analyzed to correlate the design of the mine layout to the resulting overburden failure response. Determining the extent of caving and fracturing is important in the and and semiarid Western United States because of the possible consequences to the fragile underground hydrologic systems upon which the land owners and users depend. This study is unique from past investigations because the overburden contains massive sandstone members that impose special conditions on the caving process and pressure redistribution above the longwall panels. This paper presents the results of this correlation study.

Jan 1, 1992

By Miller J. D

The mechanism of adsorption of gold from alkaline cyanide solutions by carbon has been the subject of much research over the past decade. In this paper, the nature of the gold cyanide adsorption phenomenon is investigated, particularly with respect to carbon substrates and associated surface adsorp- tion sites.

Jan 1, 1991

By A I M Ritchie

The pyrite oxidation rate is a process central to both the performance of bio-oxidation heaps, used in the pre-treatment of some refractory gold ores, and to the levels of pollution in acid rock drainage (ARD) from pyritic waste rock dumps. A goal in bio-oxidation heaps is to achieve high oxidation rates in the heap as a whole. In comparison, one way to mitigate the environment impact of ARD, is to reduce the overall oxidation rate in the waste rock dump since pyrite oxidation is the primary pollutant generation process. In both bio-oxidation heaps and waste rock dumps the overall oxidation rate of the pyritic material (the intrinsic oxidation rate) at these sites. Much research has been conducted over the last 40 years or so on the oxidation rate of pyritic material with particular emphasis on the catalytic role played by bacteria. More recently mathematical models and field measurements have clarified the extent to which oxygen transport rates are rate limiting, what the dominant oxygen transport mechanisms are and the physical properties of the heaps which have most impact on these transport rates and on the overall oxidation rate. How the performance of bio-oxidation heaps can be optimised and how the pollution load in drainage from waste rock dumps depends on gas transport mechanisms is briefly reviewed. The sensitive of the overall oxidation rate in bio-oxidation heaps and waste rock dumps to details of the intrinsic oxidation rate is quantified.

Jan 1, 1994

By S Wangchai, D B. Hastie, P W. Wypych, A P. Grima

Industries that handle and process ‘dusty’ ores are facing increasingly difficult challenges to ensure sustainable operation and development. Most existing dust-control measures treat only the symptoms of dust generation and do not deal with the root cause/s of the problem. Many of these methods are also relatively inefficient in terms of controlling dust emissions. This paper summarises the various existing options available for dust control and some of their features, advantages and disadvantages. It then describes some of the new technologies that are being researched, developed and employed to minimise dust emissions by addressing dustability or dustiness and the dust generation mechanisms found in industry. Recent research results and case studies are presented to demonstrate some interesting findings obtained from this work. With improved understanding and modelling of dust generation mechanisms and bulk material dustiness, it is possible to achieve a step-change improvement in the design, troubleshooting and application of more efficient dust-control technologies.CITATION:Wypych, P W, Hastie, D B, Wangchai, S and Grima, A P, 2015. Research and application of new dust control technologies for the iron ore industry, in Proceedings Iron Ore 2015, pp 529–536 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By K H. Esbensen

During the next five years Denmark will implement a significant reduction in the national CO2 emissions to fulfil the Kyoto Protocol. The energy sector is central for achieving this goal and extensive use of renewable energy is the most important single factor contributing to reduce emissions of greenhouse gases. DenmarkÆs renewable energy sources comprise wind energy and biomass. Wood chips and straw are the dominant type of biomass in Denmark. More than 500 000 tons of wood chips are used annually, currently with rapidly growth prospects. This contribution focuses on sampling of wood chips.

Jan 1, 2005

By Lawson E, Purkiss S. A R, Van Ashwegen p C

It is only in the past decade or so that industrial exploitation of biological resources and techniques has become regarded as a distinct discipline. Commonly referred to as Biotechnology, it embraces biochemistry, microbiology and the engineering sciences and is mainly aimed at the biological conversion of suitable raw materials into desired end products. The catalytic agents are more often than not bacteria although other micro-organisms such as fungi are used. The range of micro-organisms used is wide and the choice depends upon the desired end product, which in turn depends upon the metabolic attributes, genetically engineered or otherwise, of the cells. The metabolic diversity of micro-organisms has been applied to processes such as antibiotic production, food processing, brewing and chemical production, and of course extraction of metals from ores. Metabolic diversity is, to a certain extent, based on nutrition, which, in its simplest form, can be divided into energy source, carbon requirements and nature of the electron donor producing reducing power to the cells. The source of energy may be light, in which case the organisms are phototrophic (eg green plants, algae). The carbon requirements and reducing power may come from organic sources. These organisms are then called heterotrophic (eg man and most bacteria, including the well known Escherichia colt). However, there is a group of bacteria whose energy metabolism depends upon chemical redox reactions, use inorganic carbon (CO2) and obtain their reducing power from reduced chemicals such as metal sulphides. These are known as chemolithotrophs. They play an important role in mineral recycling in nature and are also ideal for extraction of metals from ores. This is because they are extremeophiles being acidophilic (grow at very low pH) and sometimes also thermophilic (grow at very high temperatures). These bacteria operate in such hostile environments that competition, or contamination, by other organisms does not occur. Extraction of metals from ores by chemolithotrophic bacteria is commonly referred to as biohydrometallurgy. Other related areas are bioadsorption of metals from dilute solution,- microbial treatment of metal contaminated wastes and removal of toxic chemicals produced or used during mineral processing. This paper basically reviews the work that Gencor has undertaken in the field of biohydrometallurgy and the advancements it has made in commercialising the technology, but also touches on certain long-term areas of research that are currently under investigation.

Jan 1, 1995

Geotechnical practice combines the site engineering geological model with engineering design and operations to control risk. The responsibility of the geotechnical professional is to present relevant engineering geological information to an engineer to effectively impact an outcome. Return is enhanced by understanding expected operating and capital cost due to ground conditions.   Risk is effectively communicated by a successful geotechnical practitioner. In a mining environment the need is to assess ground conditions accurately and quickly, and to effectively communicate expected ground response due to mining. A good engineering geological model includes a description of geotechnical engineering parameters to design assuming reasonable expected soil, rock and water conditions. Pit slopes are steepened, stope spans widened and waste foundations and land forms are constructed all under geotechnical control.   The responsibility of the geotechnical professional is to collect, assess and disseminate relative engineering geological information. The geotechnical professional is a person advising on ground related engineering, and generally operates within geology and engineering end members.   Return is better assessed on an understanding of ground cost. In operations the goal is to meet production at lower cost. In evaluation, regional and exploration geology, mine design and expected operational factors influence expected cost and project return. Return allows companies to meet shareholder expectations, attract equity to develop and add value to the community.   This paper presents a discussion with some examples to present an approach and design philosophy for geotechnical practice in the mining industry.

Jan 1, 2004

The resource sector is conservative industry and people are resistant to change. The methods and procedures used to implement changes in process plants ultimately determine the success of such changes. The financial managers have a large say in where money is spent and the technical personnel must justify the cost and benefits for any expenditure. There are also others who believe it canÆt be done û æwe tried thatÆ. Implementing change needs a æChampionÆ who can assess the risks, plan, define the objectives and scope, set the goals, determine the key performance indicators (KPIs) and stay focused. This also requires preparing a budget and schedule and measuring against this. Contract management, reports and reviews are part of the implementation. Several case studies are given as examples of the implementation of process design changes to highlight the critical aspects involved.

Jan 1, 2009

By Estoque J, Lodrigueza L, Rebillon F

Ore mineralization in Masara consists mainly of gold-silver veins, porphyry copper and pyrometasomatic deposits related to left-lateral movements along the Philip- pine fault system and a later stage of magmatism. These are hosted by pre-Tertiary volcanic flows and volcaniclastics, and comprise a temporal pattern of earlier peripheral copper zone, an intermediate mixed copper-gold area and a later central gold vein system within the Masara sector of the postulated volcanic field. Gold ore emplacement occurred in at least two stages, and shows gradations from a lower mesothermal-epithermal phase passing into a typical epithermal zone, and finally into a truncated, or poorly developed, upper level thermal spring deposit. Orebodies are closely associated with hot springs, solfatara and several magma- related masses, emphasizing their inherent linkage with a geothermal system in the Area.

Jan 1, 1987

By G N. Musafer, M H. Thompson, R C. Wolff, E Kozan

The most important aspect of modelling a geological variable, such as metal grade, is the spatial correlation. Spatial correlation describes the relationship between realisations of a geological variable sampled at different locations. Any method for spatially modelling such a variable should be capable of accurately estimating the true spatial correlation. Conventional kriged models are the most commonly used in mining for estimating grade or other variables at unsampled locations, and these models use the variogram or covariance function to model the spatial correlations in the process of estimation. However, this usage assumes the relationships of the observations of the variable of interest at nearby locations are only influenced by the vector distance between the locations. This means that these models assume linear spatial correlation of grade. In reality, the relationship with an observation of grade at a nearby location may be influenced by both distance between the locations and the value of the observations (ie non-linear spatial correlation, such as may exist for variables of interest in geometallurgy). Hence this may lead to inaccurate estimation of the ore reserve if a kriged model is used for estimating grade of unsampled locations when non-linear spatial correlation is present. Copula-based methods, which are widely used in financial and actuarial modelling to quantify the non-linear dependence structures, may offer a solution. This method was introduced by Bßrdossy and Li (2008) to geostatistical modelling to quantify the non-linear spatial dependence structure in a groundwater quality measurement network. Their copula-based spatial modelling is applied in this research paper to estimate the grade of 3D blocks. Furthermore, real-world mining data is used to validate this model. These copula-based grade estimates are compared with the results of conventional ordinary and lognormal kriging to present the reliability of this method.CITATION:Musafer, G N, Thompson, M H, Kozan, E and Wolff, R C, 2013. Copula-based spatial modelling of geometallurgical variables, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 239-246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

The mining of remnant coal reserves at the Liddell Open Cut is subject to a number of risks. These risks are of both a technical and financial nature. Liddell Open Cut is principally a conventional truck and shovel/loader operation, supplemented by a highwall coal augering operation. There are significant areas of divergence from more conventional operations including working in close proximity to a major dam, working up dip from an operating underground mine, and working through areas where there has previously been underground extraction. In addition the site has major long-term rehabilitation requirements. This paper, rather than concentrating on specific detail of areas of risk, presents the spectrum of geological, design, operational and post-mining risks that accrue to the various areas of activity in this open cut operation. The balance of this paper then provides an outline of the strategies employed by Liddell Coal to manage their potential impact.

Jan 1, 1994

It is no longer adequate in running mines and quarries to simply select the best equipment. Today's competitive international commodity markets demand superior efficiency. This requires efficient production and commercial processes together with systematic involvement of people in continuous improvement of processes. True Total Quality of Management (True TQM) principles provide an operating philosophy for maximising productivity and minimising unit costs of output. Unfortunately, even though these principles are proven in all industry sectors worldwide, they have not always been used correctly. This paper describes basic methodology for correct use of these principles to successfully improve the productivity of rock breakage production processes.

Jan 1, 1995