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The mining. operations of Bougainville Copper Pty Limited are located at Panguna on the Island of Bougainville which is part of the Territory of Papua and New Guinea. Mineralisation in the Panguna area was first established by C.R.A. Exploration Pty Ltd in 1964. Exploration work since then has established ore reserves estimated to be 760,000,000 tons of.0.47% copper and 0.4 dwt./ton gold. An economic feasibility study completed in July of this year has enabled a decision to be made to proceed with a major mining operation. The ore will be mined by open cut methods and will be treated in a conventional concentrator with a nominal capacity of 90,000 short tons per day. The concentrate will be pumped as a slurry through a 15 mile long pipeline to a port established on the east coast where it will be filtered and dried ready for export. Other supporting facilities for the mine include two towns, a 135 megawatt steam power station, and access roads.

Jan 1, 1970

At Hilton Mine, 18 kilometres north of Mount Isa, the silver-lead-zinc sulphide bodies have undergone strong deformation in the form of folding and later faulting and brecciation in the hangingwall region of the mine. Variation in grades and widths over compara- tively short distances causes problems regarding accurate sampling of orebody exposures in underground development, and in defining confidence limits for the extrapolation of ore intersections in ore reserve calculations. The paper gives a preliminary insight into the problem of obtaining representative samples for exposed orebodies and discusses the sampling techniques employed. Results gained from these sampling methods could not be verified due to lack of individual bulk samples for comparison but strong evidence for precision was provided. INTRODUCTION In a developing mine like Hilton, accurate grade information is of extreme importance. Original grade information for a potentially viable ore deposit is gained from surface drilling, and initial ore estimates are calculated from the resultant ore widths and grades. After underground development has proceeded, the opportunity arises for detailed examination of orebody exposures, and the resultant assay grades and widths from sampling of these exposures may, in the long term,

Jan 1, 1976

By M A. Harrington-Baker, J M. Trudnowski

Sulfate-reducing bacteria (SRB) have the ability to immobilise dissolved metals by precipitating them as sulfides, provided that a favourable biochemical environment is created. Such an environment includes the presence of sulfate, anaerobic conditions and the availability of organic carbon. If such conditions are engineered within a reactive barrier or field-bioreactor, most metals can be effectively removed. To demonstrate this concept, three passive SRB field-bioreactors were constructed in 1998 at an abandoned mine site in the vicinity of Butte, Montana, USA to treat acid mine drainage with characteristic elevated concentration of metals and low pH. Performance of the field-bioreactors, using aqueous samples, was monitored over 32 months until the project was terminated, field-bioreactors were decommissioned and solid matrix sampling of the reactive matter was performed. The most important analytical results are presented in this paper together with conclusions regarding the appropriateness of the field-bioreactors construction features. Only Zn, Cu, and Cd were being removed as sulfides due to SRB activities. Changes in concentrations of other metals (Fe, Mn, Al, As), which do not necessarily precipitate as sulfide, seemed to be affected by SRB only in an indirect manner by responding to increased pH caused by SRB activity. An innovative cellular containment system used for placing organic matter worked very well in preventing settling of the organic matter and ensuring uniform flow of AMD throughout the entire cross-section of the organic carbon with no preferential flow paths This demonstration was funded by the US EPA and was jointly administered by the EPA and the US DOE under DOE contract number DE-AC22-96EW96405. The project was implemented by MSE Technology Applications, Inc, Butte, Montana, USA.

Jan 1, 2003

By Van Hoorn PD

For the development of BHP's Gregory open cut coal mine in Central Queensland a mini computer was successfully used to assist staff in the evaluation of the deposit and the planning of the mine. The Gregory deposit is essentially a single mineable seam deposit, however the systems developed may be applied to other coal deposits including multi seam occurences. The first phase of the Gregory computer evaluation and planning project involved the establishment of a borehole data base for the storage, retrieval and analysis of both strata and quality data. During the second phase a numeric block model of the coal deposit was created. Using this model reserve calculations were carried out by specifying the area with the aid of a digitizing tablet. The third phase involved the develop- ment of systems to simulate the dragline stripping operations including the rehandle percentage calculation, a dragline production schedule showing coal quantity and quality exposed, and a combined multi dragline operation schedule that can produce figures and graphs for up to 20 variables. A derivative of the operating plan was a programme that gave productioh cost estimates

Jan 1, 1978

The 5.6 km Canning Tunnel was constructed to improve water supply from Canning Dam to the Perth metropolitan area. The site area is in the Darling Range which is essentially a laterite-capped plateau-remnant underlain by Archaean granitic rocks, intruded by dolerite. Two arrangements were available. After geotechnical investigations which included geological mapping, seismic refraction geo- physics, diamond drilling and mechanical rock testing, a single tunnel was selected in pre- ference to two short tunnels and a connecting pipeline. The tunnel is hydraulically equivalent to a fully lined tunnel 1.83 m in diameter and 5 580 m long. The alignment diverged from a straight line so that the initial upstream section was almost normal to the contours which allowed for minimal support requirements in a weathered zone. Although steel and con- crete lining was needed at both ends, the main section of the tunnel was unlined except for a concrete floor. A sand and rock trap with a capacity of 46 m3 was constructed near the outlet portal to collect debris and sand down to a size of about 2 mm. Portal excavations were in highly to completely weathered rock which extended 56 m into the tunnel at the upstream end, and 18 m at the downstream end. Conventional drilling and blasting were used for tunnel excavation with survey control by laser. Breakage lEngineering Geologist, Mines Department, Perth, W.A.

Jan 1, 1976

By D Teyhan, J Kirsch

Traditionally, most Australian iron ore mining operations have been surface-based. Processing plants were designed to handle dry ores. In recent years mining operations in the Pilbara have progressively moved below the water table exposing wet, sticky ores which have caused lost efficiency in screening operations as particles tend to agglomerate and adhere, blinding screening media. Miners and vibrating screen manufacturers have experimented with a shift from linear motion to elliptical motion screens. Elliptical motion conveys and lifts particles. Effective on flat deck (horizontal and inclined) or sloping decks it can be configured to provide a controlled transport rate, applying pressure in all directions to maximise screening efficiency. In practice, elliptical motion screens have proven to be effective in dislodging sticky particles from screening media, reducing blinding rates and improving screen efficiency. Moisture and clay content change during the life of a mine. These changes are sometimes the effect of seasonal rainfall, in other cases due to increased groundwater and clay content as mining operations go deeper. To compensate for such changes and optimise screen efficiency, changing the ‘shape’ of elliptical screen motion is required. This has traditionally required shutting down processing plants and making mechanical screen adjustments. Plant downtime is costly and machine adjustment has been a ‘trial and error’ practice. This paper will explore the results of a field trial that is currently underway in Brazil of a next generation elliptical motion screen design that allows operators to make changes to exciter rotational direction, speed and screen stroke angle, through electronic drive phase control. The machine’s electronic drive system synchronisation is enhanced for stability with a unique mechanical timing system. Operating at up to 6 g, screen adjustments can be made on the fly without stopping production. Early trial results are showing up to 50 per cent improvement in screen efficiency compared with traditional elliptical motion machines under certain feed conditions.

Aug 24, 2022

By D Teyhan, J Kirsch

Traditionally, most Australian iron ore mining operations have been surface-based. Processing plants were designed to handle dry ores. In recent years mining operations in the Pilbara have progressively moved below the water table exposing wet, sticky ores which have caused lost efficiency in screening operations as particles tend to agglomerate and adhere, blinding screening media. Miners and vibrating screen manufacturers have experimented with a shift from linear motion to elliptical motion screens. Elliptical motion conveys and lifts particles. Effective on flat deck (horizontal and inclined) or sloping decks it can be configured to provide a controlled transport rate, applying pressure in all directions to maximise screening efficiency. In practice, elliptical motion screens have proven to be effective in dislodging sticky particles from screening media, reducing blinding rates and improving screen efficiency. Moisture and clay content change during the life of a mine. These changes are sometimes the effect of seasonal rainfall, in other cases due to increased groundwater and clay content as mining operations go deeper. To compensate for such changes and optimise screen efficiency, changing the ‘shape’ of elliptical screen motion is required. This has traditionally required shutting down processing plants and making mechanical screen adjustments. Plant downtime is costly and machine adjustment has been a ‘trial and error’ practice. This paper will explore the results of a field trial that is currently underway in Brazil of a next generation elliptical motion screen design that allows operators to make changes to exciter rotational direction, speed and screen stroke angle, through electronic drive phase control. The machine’s electronic drive system synchronisation is enhanced for stability with a unique mechanical timing system. Operating at up to 6 g, screen adjustments can be made on the fly without stopping production. Early trial results are showing up to 50 per cent improvement in screen efficiency compared with traditional elliptical motion machines under certain feed conditions.

Nov 8, 2021

By D Yan, D Connelly

Beneficiation of magnetite is an integral part of the future of iron ore processing. Historically, the focus of Western Australian producers has been on exporting direct shipping ore (DSO) namely haematite. The future for new DSO resources is limited so companies are changing their emphasis into processing the very large, undeveloped magnetite ores in Western Australia (WA), using beneficiation to produce shippable magnetite concentrates. These magnetite resources require higher cost processing techniques such as fine grinding and beneficiation to produce saleable concentrates. This distinct difference, from the DSO ores, has led to the development of a number of new technologies. This paper reviews: the different techniques used for magnetite beneficiation and provides some case studies in the WA industry; the use of mineral liberation analysis (MLA) to describe the nature, grain size, occurrence and associations of the mineralisation;the consideration of coarse cobbing as a critical upgrading; the application of high pressure grinding rolls (HPGR) to save energy; how the field of magnetic separation has resulted in new machines with higher field strength (SLon Separators); ultra fine grinding requirements of magnetite concentrates; andthe application of reverse flotation to reduce silica in the concentrates.

Jan 1, 2009

By Hewitt D

A study of two laterite profiles developed on a serpentinite near Rockhampton, shows that loss of Si02 and MgO results in the relative concentration of Fe203, A1203 and a number of minor elements. Serpentine is broken down to form montmorillonite, goethite, quartz and kaolinite. Enrichment of nickel occurs, and it is shown that the element is mainly associated with montmorillonite and serpentine. Highest nickel values are associated with a zone in the profile which occurs at a depth of 10.5-22 metres, and the bulk of the nickel in this zone (42-80%) is associated with the

Jan 1, 1974

A mining companyÆs approach to managing the risk of theft of explosives and initiating devices should be underpinned by an organisation-wide policy developed with internal and external consultation. It should be based on the principles of sound proactive risk management, planning, monitoring and remedial action. This paper aims to provide mining (and construction)organisations with the rationale and many of the tools they need to control explosive security risks. As with all legislative compliance, they are best managed by incorporating the statutory and legal requirements into company policies, management systems and plans, operating procedures and culture. This is the approach that has been adopted in this paper. Trends we should expect: more prescriptive legislation and stricter government regulations; enhanced enforcement and more prosecution; more sophisticated detection systems, eg airports; additional compliance costs; additional vigilance on record keeping; improved risk awareness and risk communication; wider use of explosives policies, management systems and plans; and additional security staff with investigative skills.It should be noted that mining companies will be required to play their part in reducing the likelihood of explosives, intended for mining purposes, being wrongfully used to threaten, hold to ransom or to injure individuals or members of the public or to produce property damage. This will be done by putting in place safeguards to reduce the risk of theft of explosives while they are under their control. On that basis, this is a business risk assessment rather than a hazard risk assessment. A conclusion of this paper is that mining companies can and should play their part in reducing the supply of explosive materials that can then be used for illegal activities. In fact, mining companies have always had this duty, but now the stakes are higher û æcomplacency no longerÆ.

Jan 1, 2004

By Dorricott M. G

Ballarat Goldfields NL is developing an exploration decline at Ballarat East using a Mitsui Miike S-125 roadheader. To-date, 530 in of advance has been achieved at an average rate of 16.1 m/week. Roadheader availability has averaged 94.3 per cent, and pick consumption has averaged 0.016 per m. Ground support has involved pattern rockbolting with split sets, 100 mm thick fibre reinforced shotcrete, and steel sets as required. The slower than expected advance rate has mainly been due to difficult ground conditions. It is expected that a further 970 in of decline will be mechanically excavated before a drill and blast system becomes more economical.

Jan 1, 1995

By D R. Seaman, R P. Tooher, B A. Seaman

"Several mine scheduling tools exist for use in optimising and scheduling the reserve according to in situ value. These tools generally value the ore on a per block basis according to regressed recovery models based on ore grade and type. It is then the task of the plant metallurgist to ensure that these ore blocks are fed to the plant in a manner that satisfies the prevailing plant constraints. This task is often completed in complex Excel® spreadsheets that are modified over time with factors applied to account for plant modifications or limitations.It is the authors’ experience that this approach is difficult to audit and replicate in a consistent manner. Furthermore, operational decisions, such as primary grind size or autoclave oxidation are made on the metallurgist or managements’ perceived optimum value and does not necessarily represent a cash flow based optimum.Many processing plants contain multiple internal constraints. As ore feed grades and properties change over the life-of-mine (LOM), processing-bottlenecks shift from one unit process to another and different operating strategies need to be adopted to maximise cash generation from the process.This paper presents a unified optimisation approach to scheduling ore based on a circuit mass balance to describe the process plant with individual models for each significant unit operation. The approach allows for optimisation over multiple input variables and the inclusion of linear and non-linear constraints.This optimisation process has been applied to different complex gold operations. The end result is an automated scheduler that selects the optimum blend of ores as well as plant operating conditions that satisfy all internal plant and shutdown constraints while maximising the objective of choice (metal production or cash flow). The models are also valuable for evaluating expansion or debottlenecking opportunities of individual processing units. These models are coded in Matlab® R2016a provided by MathWorks®, and can be deployed to end users in a compiled version with significant savings in time to run different scenarios over the Excel®-based systems.Citation:Seaman, D R, Tooher, R P and Seaman, B A, 2016. Optimisation of Complex Gold Processing Plants with Multiple Unit Operation Constraints - the Newcrest Planning Scheduler, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 191–198 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By A A. Puhalovich

The placement of chemically reactive mine wastes in mined out pits (æpit backfillingÆ) is increasingly seen by industry as best practice to manage long-term environmental risks. This is primarily because leaving wastes at the surface, or allowing pit lakes to develop, can result in unacceptable environmental risks. The costs and practicality of mitigation options such as installation of covers and community expectations of landform re-construction to achieve a post-mining, beneficial land use are also important drivers for pit backfilling.Pit backfilling can significantly reduce the post-closure risks to receiving environments, by minimising seepage due to tailings, acid/solute generating waste rock and/or salts derived from mine water treatment. Environmental risks are often highest where wastes are located close to the ground surface, due to relatively high rates of groundwater movement in near-surface aquifers and/or failure of engineered structures due to rainfall/erosion processes. Placement of these wastes at significant depth in pits, subject to mine planning and environmental assessment, can address these risks by increasing the path length and resistance from contaminant source to receptor, thus enhancing encapsulation of the wastes.Pit backfilling can also be cost-effective for mining companies. This is because existing pits are developed on the basis of an economic return and thus provide an opportunity to store tailings in an existing æengineered structureÆ at little or no incremental cost when compared with building and operating a new tailings or waste rock storage facility, often encompassing complex cover/drainage management systems. Key issues for consideration are mine planning, the long-term geotechnical behaviour of the wastes (eg consolidation of tailings which leads to release of acid/solutes in tailings porewaters), seepage rates to downstream receptors/agreed end point criteria and potential resource sterilisation. Internationally, mine closure guidelines are also showing a greater recognition of pit backfilling in the context of allowing mining companies to meet agreed post-closure land use objectives.In summary, pit backfilling can enhance the encapsulation of chemically reactive mine wastes and environment protection, and with agreement on post-closure beneficial land use, can also help to deliver post-closure benefits to communities.CITATION:Puhalovich, A A, 2012. Pit backfilling - Managing chemically reactive mine wastes and achieving rehabilitation objectives, in Proceedings Life-of-Mine 2012 , pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By W Mahoney, F Clement, E Saraiva

Prefabricated waterproofing sheet membranes are extremely complicated to install in underground sections with complex geometries and, despite being already subjected to quality tests in the factory, the installed membrane often exhibits leakages due to different reasons. Main sources of leaks are the required high amount of welding seams and damages caused during installation of reinforcement, as well as overstretching and poorly installed secondary concrete linings. Also the design of the tunnel lining is strongly influenced and limited by the use of prefabricated waterproofing sheet membranes. The use of sprayed waterproofing membranes for more than a decade has contributed to durability and serviceability, as well as to increasing sustainability of tunnel linings. The presented sprayed waterproofing membrane MasterSeal 345 is an advantageous alternative to prefabricated waterproofing sheet membranes under typical tunnelling conditions, especially in geometrically complex areas, such as in lay-by niches, cross passages and crossover caverns, where installation of conventional waterproofing membranes is inherently difficult, and locating leaks is challenging. This membrane has been successfully used in underground projects with different waterproofing design concepts and under diverse hydro-geological and environmental conditions for over a decade. It provides tunnel designers with different options and optimisation for the design of the tunnel concrete lining. Additional advantages to owners, contractors and designers from the use of the sprayed membrane include flexibility in the design, increased productivity and flexibility in working programming, as well as improved logistics, resulting in significant program and cost savings and reduced long-term maintenance costs. This paper describes the key features of this sprayed waterproofing membrane, its application range and limitations, the waterproofing concept, design options and related benefits. Further, guidance for membrane application and quality control and a summary of two recent project references in the United Kingdom and in Switzerland are provided.CITATION:Saraiva, E, Clement, F and Mahoney, W, 2014. The use of sprayable waterproofing membranes in underground structures – concept, design options, benefits and limitations, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 323–332 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By P Woodward, T Ly, N Muhamad

OZ Minerals' Prominent Hill copper-gold concentrator is located 650 km north-west of Adelaide in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a design capacity of 8 Mtpa. The flotation circuit includes six rougher cells, an IsaMill for regrinding the rougher concentrate and a Jameson cell preceding the three stage conventional cell cleaner circuit.Since its commissioning, the Prominent Hill flotation circuit has been the focus of a series of projects aimed at continual performance improvement. This has been achieved by a systematic approach of project identification, evaluation and implementation which has led to a progressive improvement in flotation performance. Innovations that have been successfully implemented include aspects of cell design and operation, and reagent suite optimisation.Improvements to the mechanical cells initially focused on the installation of a modified rotor-stator design in the rougher circuit, as recommended by Outotec. Isolated cells were fitted with this technology and proven to provide a benefit for copper recovery before the design was trialled in subsequent cells along the bank. Based on this success, further modifications were made to other aspects of the rougher and cleaner cells.Laboratory trials conducted at Prominent Hill involve a screening process identifying potential reagents from a list of products, which are then rigorously tested in the laboratory before one is selected for trial in the concentrator. Where these reagents have demonstrated a statistical improvement in performance they have typically been incorporated permanently into the flotation circuit. This paper discusses the process of continual improvement at the Prominent Hill flotation circuit and the optimisation achieved by the implementation of key initiatives.CITATION:Woodward, P, Muhamad, N and Ly, T, 2013. Optimisation of the Prominent Hill flotation circuit, in Proceedings MetPlant 2013 , pp 431-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By J Simpson, M Johnston

Recently Mount Isa Mines undertook a study to review the lead-zinc orebodies to extent of resource and reserves and determine the new life-of-mine schedule, as the Mount Isa and Hilton orebodies had not be reviewed for many years. Also, the recovered value of the Mount Isa, Hilton and George Fisher orebodies had been increased by major performance improvements in the lead-zinc concentrator. The Mount Isa Lead-Zinc concentrator processes fine-grained lead-zinc ore from the Mount Isa, Hilton and George Fisher orebodies. These orebodies have varying levels of pyrite and large variation in the grain size and texture of the galena, sphalerite and pyrite. This variation has a large effect on the recovery of the lead and zinc in the concentrator. Some ores achieve 90 per cent recovery at target grades, yet other ores are unable to achieve æsaleableÆ concentrate grade, with no metal being recovered to concentrate and therefore effectively losing the contained metal to the final tailings. Models were created to predict the metallurgical performance of these orebodies, to better reflect the variation that occurs. These improved metallurgical models and economic data allowed the determination of the Net Smelter Return (NSR) for each block in the geological block model. This NSR is the return to MIM of the metals contained in concentrate. The NSR was used as the cut-off grade criteria when determining the value of the ore. This formed the basis of the lead-zinc life-of-mine schedule and the optimisation of the lead-zinc business.

Jan 1, 2003

By H Asche

The Melbourne Metro project has evolved from the Victorian Transport Plan. MM1 is the second major phase of the proposed separation of Melbourne’s radial railway system, creating a line that will operate independently across the metropolitan region. The central section will run beneath the inner suburbs and the central city. The initial project comprises nearly 8 km of twin bore tunnels, three cavern stations and two cut and cover stations, as well as a dive structure and connections with the existing rail system. This paper describes the development of the geological model, a modification of the rock mass classification system derived during the EastLink project and the influence of the geology on the design of the tunnels and stations for the Department of Transport’s business case.The majority of the tunnelling will be in the siltstone and sandstone bedrock. This material has been extensively folded, sheared and intersected by igneous intrusions. A revised rock mass classification system has been developed for the Melbourne Formation to assist in identifying the important engineering properties of the rock and to rationalise the support types required.The Metro’s tunnel alignment crosses the Yarra Delta deposits in the lower reaches of the Moonee Ponds Creek and again at the Yarra itself near Princes Bridge. These deposits vary in extent and thickness over very short distances. The investigation of these materials has been carried out using conventional drilling techniques in conjunction with sonic drilling methods.Over the central section of the Metro, the positions of the new station are determined largely by transport planning requirements and urban development opportunities. However, the stations, and the tunnels, have been the subject of studies, optimising exercises, and selection processes to arrive at the concept design. This paper describes the influence of the varied geology on the development of the design, and the identification and management of the risks in tunnelling under the centre of Melbourne.

Mar 8, 2011

By M Bouare, C Holland, K N’Diaye

Two adjacent open pits in Mali hosted by deeply weathered saprolitic materials were mined consecutively over the course of approximately 12 months. During excavation, both pits experienced significant displacement and tension cracking as the result of deeper than expected depth of weathering coupled with relatively steep slope angles and significant groundwater. In response, geotechnical and operations teams overcame numerous monitoring challenges with prisms and radar to develop a simple and effective monitoring system coupled to a Trigger Action Response Plan (TARP) which enabled continued safe operations while reducing ore loss. Observations of previous slope performance of these two pits allowed for greater confidence in empirical failure runout calculations that was used to specify the standoff widths for the exclusion zones in the pit. Back analysis of the slope as-built performance after the first indications of slope distress was also conducted. The back analysis was used to confirm rock mass parameters for modelling while being utilised as a reality check for the stability analysis. The stability analysis indicated that leaving a large step-out or buttress would not prevent the displacement, resulting in some ore being sacrificed to ensure the safety of personnel. Key learnings from this experience highlight the importance of: • up-to-date geological interpretation of the depth of weathering • ensuring slope design guidance is reviewed and updated as latest information (ie geology and monitoring) is received • having multiple complementary slope monitoring methods to ensure redundancy • ensuring visual observations and as-built performance are utilised as a reality check to provide greater confidence in stability analysis and design guidance.

Jun 22, 2022

By Collins M. J, Ozberk E

A major advantage of the Sherritt Zinc Pressure Leach Process is the conversion of sulphide sulphur in zinc concentrate to elemental sulphur during pressure leaching. Elemental sulphur can be recovered as a marketable byproduct by flotation of the leach residue, and melting and filtration of the sulphur flotation concentrate. The behaviour and deportment of sulphur during pressure leaching, flotation, and melting and filtration are discussed in this paper using data obtained from the treatment of a wide variety of zinc concentrates in the laboratory miniplant at the Sherritt Research Centre. The quality of the elemental sulphur byproduct and a process for purifying the sulphur are also Presented.

Jan 1, 1993

By Diessel C. F K, Ng N

The commonly used Stopes-Heerlen coal petrographic classification and nomenclature has over the years been subject to variable interpretations. This paper discusses the problem with specific reference to the inertinite maceral group. The effect of various interpretations of the Stopes-Heerlen system on maceral analysis is discussed and illustrated by means of comparative analyses conducted by a number of laboratories in Australia. An attempt is made to define the reflectance thresholds used by the authors to subdivide the inertinite group; the genetic and technological significance of these thresholds are compared. The difficulties of distinguishing structured and non-structured macerals of the inertinite group is discussed in terms of possible improvements to the present Stopes-Heerlen system by extending the classification to include transitional maceral types.

Jan 1, 1969