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By D Reid, J McKibben, M Noppe

International mineral disclosure standards and guidelines aligned with the CRIRSCO (Committee for Mineral Reserves International Reporting Standards) template were developed to inform stakeholders about the relative accuracy and confidence levels of publicly reported information and to support investment decisions, particularly when advancing projects through different development stages. The traditional stages range from early to advanced exploration, through pre-development (with Mineral Resources and pre-feasibility and/or feasibility levels of study) before the final development stages, where a decision to proceed with construction or production (or both) is made. The traditional definition of Mineral Resource and Ore/Mineral Reserve classification categories and techno-economic study levels (including Preliminary Economic Assessment (PEA), Scoping Study (SS), Pre-Feasibility Study (PFS) and Feasibility Study (FS)) were defined with pre-development project assessment in mind. As such, these definitions are not necessarily well aligned to the reporting structures required by operating mines which need to consider a range of timelines spanning short to long-term operating conditions. However, the same terminology and definitions are used, or expected to be used, by both project developers and mine operators when reporting resources, reserves and techno-economic study outcomes. This paper discusses how various stakeholders in the minerals industry (including competent/qualified persons, mining company leaders, investors, lenders and regulators), generally interpret the definitions of Mineral Resource and Ore Reserve categories in terms of the relative accuracy of the estimates, their link to techno-economic study levels and their contribution to life-of-mine (LOM) schedules. The paper examines the degree to which mining companies recognise, and apply, enhanced operational knowledge to reflect short-term views of the relative accuracy and confidence levels associated with publicly reported Mineral Resource and Ore Reserve estimates and forecasts. Furthermore, this paper explores how this knowledge is applied to support ongoing Mineral Resource, and particularly Ore Reserve, generation and reporting. This paper is informed by public data and responses to an internal survey prepared by the authors and completed in 2021 by several mining companies.

Mar 22, 2022

By J Bolen, I Cameron, M Huerta, M Okrutny, K O’Leary

As greater amounts of fine iron ore concentrates enter the marketplace, new investments in iron ore pelletising capacity are inevitable to deliver these concentrates to steel industry consumers. When investors assess the two well-proven pelletising technologies, the straight grate and grate-kiln, the most appropriate choice may not be immediately evident. Certain technical, market and site-specific factors will favour one technology over the other; investors need to be aware and understand these factors in order to make the best investment decision. Hatch has compared the merits of both technologies regarding plant configuration; type of iron ore processed; energy consumption and flexibility to use a variety of fuels; ability to produce the required pellet quality; required plant capacity and scale; operating and capital costs and environmental performance. A technology assessment checklist that investors should consider when making a new pellet plant investment decision is presented.CITATION:Huerta, M, Bolen, J, Okrutny, M, Cameron, I and O’Leary, K, 2015. Guidelines for selecting pellet plant technology, in Proceedings Iron Ore 2015, pp 45–52 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By R Jia, J T. Waldram

"The Caijiaying lead zinc mine is located in China, north-west of Beijing, in Hebei Province. The region experiences severe winters, below -35°C, and warm summers, up to 30°C. The mine and concentrator commenced operations in the second half of 2005 with a conventional tailings disposal system consisting of a tailings dam with peripheral ring main discharge and central water recovery. A second similar dam sharing one common wall was added later. In view of the extreme winter conditions tailings lines and ring mains plus spigots, together with return water lines, require insulation and electrical trace heating. The volume of process water trapped as ice in the tailings dam ponds each winter is significant. This seasonal variation presents a major difficulty in the management of process water availability. Although Caijiaying is an underground mine there was no backfill plant at the start of operations. As plant throughput increased more quickly than originally anticipated, tailings storage capacity became a prime concern. The construction of a backfill plant in 2007 reduced the pressure on surface tailings storage area requirements, but as suitable land on which to construct further tailings storage was both expensive and difficult to acquire, a more efficient use of the available area was required. Dry tailings storage, where flotation tailings are filtered to provide an immediate return of process water plus ‘dry’ tailings filter cake for stacking, provided an answer to both the land area required, and the water management difficulties. The paper details the reasoning behind the change and the benefits obtained at Caijiaying by moving from ‘wet’ tailings storage to ‘dry’ tailings storage.Citation:Waldram, J T and Jia, R, 2016. Caijiaying Dry Tailings Storage, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 379–382 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By B Young

Variable bench heights, interaction with underground workings and a steeply dipping orebody are challenges faced daily by geologists at Xstrata Zinc’s Black Star Open Cut (BSOC) Zinc/Lead/Silver mine in Mount Isa, Queensland.BSOC has been in operation since late 2004 and was developed to extract the surface extents of the Zn/Pb/Ag mineralisation mined in the underground lead mine. To date many large scale stopes and extensive development drives have been intersected and successfully mined. The stratigraphically hosted orebodies strike in a north-north westerly direction, dipping ~75° west. Ore production from the pit is currently at 4.5 Mt/a.Historically, sampling was conducted using a multiple spear technique from blasthole cuttings. This method proved to be relatively reliable when blasting benches at a consistent height, but a requirement to vary bench heights to safely collapse and then mine through underground workings reduced sample representivity to unacceptable levels.The purchase and commissioning of a production rig which had been converted for reverse circulation (RC) has allowed for the flexibility of a small rig, with the capacity to easily drill 48 m holes while ensuring sample quality. Sample quality is not the only benefit of introducing RC grade control. By collecting grade control data well in advance, informed decisions can be made by planning, drill and blast and mining departments weeks beforehand, rather than hours before firing. Additionally, seeking operational value to offset higher drilling costs has proved positive with benefits including increased confidence in orebody wireframes, accurate tonnage and grade for proceeding five benches along with the ability to representatively test metallurgical response on a tight grid spacing.

Aug 22, 2011

By I Gray

This paper examines the effects of the changes in stress that a coal may undergo as part of the drainage process. As a consequence of this, some coal seams will come to the situation that they have zero horizontal stress existing within them at the time of mining. The hypothesis of this paper is that this lack of horizontal confining stress means that on mining, the vertical stresses may be easily raised to a level where failure occurs. This failure may be accompanied by significant energy release from energy stored within the coal as well as that coming from the roof and floor. To determine the state of stress within the coal seam, the concept of the effective stress path that the coal passes through is examined and is found to be very dependent on the shrinkage of the coal with degassing, the Young’s modulus of the coal and its Poisson’s ratio. The Young’s modulus of the coal is important and has been found to be highly dependent on the state of stress within the coal. It may change by more than an order of magnitude.CITATION:Gray, I, 2014. The consequences for pillar stability of zero confining stress brought about by forced or natural drainage, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 331–336 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By V Pere

A geotechnical data management system has been developed to manage drillhole and mapping data generated from in house and consultant administered field programs. This system comprises a data collection interface with integrated validation, processing and reporting functionality. Development of the database required careful consideration of how and what geotechnical information is gathered in the field, a clear understanding of the interdependency of the parameters, and the outputs required to support geotechnical design.The acQuire Geoscientific Information Management System was selected as the preferred software to support the process because of its ability to easily manage data from capture in the field through to quality reviews and ultimately into reports. Initially only geotechnical logging of diamond core was considered, subsequently the system has been expanded to support additional geotechnical data sources such as laboratory test results, traverse and window mapping data. This paper focuses on the core logging data acquisition, validation, analysis and presentation of data.The acQuire Geoscientific Information Management System has proven to be a robust platform for the capture, interrogation, and reporting of geotechnical data. Data entry objects have been created to manage seven different areas of geotechnical data collection ranging from core logging to mapping to automated reports for falls of ground.

Aug 22, 2011

By R Lau

The fire safety design for road tunnels includes the following aspects: active systems, passive provisions and operational procedures. The active systems include the smoke control system, fire suppression system, detection system and fire fighter’s assistance systems. Passive provisions include escape passages, fire separation and fire resistance systems. The operational procedures refer to fire fighter access, reporting and alerts, evacuation processes and crowd control.Currently, these systems are typically designed by different designers or teams. These systems are intended to work together in a coordinated manner to provide the desired safety outcome. However, in practice, this is not always happening. The fire engineering process is supposed to bring together all these aspects and arrive at an integrated safety system. The fi re engineering process in practice is not integrating the design with the practice or reality and is thus arriving at less than desirably efficient safety systems.The example of design inputs shows how disconnected each system design basis is. The smoke control system design is based on the design fire size. The performance of the smoke control system is to achieve a smoke free environment for a defined space for a particular fire size – the design fire. The fire suppression system – most commonly sprinklers or deluge systems, is designed according to codes and to achieve a certain water discharge rate. The fire detection system is designed to detect temperature rise/rate of rise and perhaps density of smoke. Fire separation is determined to provide a certain period of service – mostly for structural elements. Escape route size and location is determined mostly by code compliance. Evacuation procedures are determined by Authority operational requirements rather than human behaviour.To arrive at an integrated fire safety system, the design basis and performances must be coordinated. An approach using fire scenarios would ensure all systems are designed to a common performance requirement. This paper will discuss how the current design approach outcomes compared with a fire scenario approach. More effective and efficient fire safety systems would require the stake holders to understand the implication of this approach and to embrace this through the fire engineering process.

Mar 8, 2011

By N J. Grigg

Gekko Systems has developed an underground pre-concentration plant (Python) to reduce mine operating costs. Many ores liberate favourably using either high pressure grinding rolls (HPGR) or vertical shaft impactors (VSI). Using these comminution circuits for mineral liberation; rather than for the final recovery process and by utilising a high mass pull, high recovery process route (gravity/flotation), a narrow, low head, compact processing plant was developed that can sensibly be operated underground. The Python underground processing plant can provide a number of advantages for narrow vein mines including lower haulage costs, improved mine call factor and lower operating costs. The focus on fine crushing reduces the power requirement of the plant to approximately 8 kWh/tonne. The Python underground processing plant has been designed to be towed down the decline or lowered down a shaft, and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a saving in mining costs and a significantly smaller environmental footprint.

Jan 1, 2008

Sishen uses a state-of-the-art tracking system to track material from its position in blast blocks through various stockpiles and crushers. Qualities are blended directly to the crusher as opposed to blending from stockpiles. This poses an interesting challenge to the planning department to simulate these conditions. The software used in these simulations are Whittle 4X and Maximiser for long-term planning, Xpac for medium-term planning and Mine Works Planner for short-term planning. Geological models and mine design layouts utilise Surpac. Sishen introduced Xpac a number of years ago; the system has developed and changed over the years. With the Sishen Expansion Project (SEP), which aims to utilise low-grade material, major changes to the planning process have to occur. SEP requires that the mine have two different plants, which utilise two different ROM feeds and have different beneficiation curves. Xpac is used to produce a rolling 18-month plan, which is as close to actual operations as possible. In order to do this, the simulations have to take into account the plants beneficiation curves, stockpile movements, hauling distance and equipment needs. On top of this, the schedule has to continually consider specifications for Fe and the contaminants. Plant yields also have to be kept within a certain bandwidth. Xpac is used to simulate the above parameters, as well as generate the raw data required to produce a mine budget. The paper will also show how the 18-month planning process and subsequent planning processes are measured and aligned. Xpac has proved to be an excellent tool to achieve these goals.

Jan 1, 2005

By S Long, D Carnovale, L Louwrens

The Mt Wright underground mine (MTW) is located near the town of Ravenswood in north Queensland and is operated by Carpentaria Gold – a wholly owned subsidiary of Resolute Mining Limited.The Mt Wright mine has gone through many stages, from the conception and implementation of the world first ‘sub-level shrinkage’ stoping (SLS) with continuous fill mining method in 2010, through to steady state production. These have been outlined in detail in papers presented by Mackay (2011) and Mackay, Long and Koen (2014) at previous Underground Operators Conferences.Since the last paper was presented, MTW has experienced significant change in two key areas.The first significant change was the discovery of a previously unknown hazard in the form of flat rilling events (FREs) from closed drawpoints (DPs). These events are believed to be unique to MTW and pose a significant risk to both the safety of personnel and the business as a whole. The paper will discuss this hazard and the evolution of the controls and practices that have been introduced to mitigate the risk posed by the identified hazards. The material involved in these events is extremely dry, fine and hot.The second significant change is an altered stress regime bought on in part by a change in the production front orientation and a general deterioration in ground conditions in some areas of the mine. This has caused some production interruptions at MTW. The second half of the paper will describe the challenges encountered, the mechanisms behind these challenges and the strategies implemented to safely return MTW production to planned levels.It is believed that other operations can learn from the issues mentioned above, and the paper has been written with this in mind.`CITATION:Long, S, Carnovale, D and Louwrens, L, 2017. Mt Wright – managing unique risks, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 295–304 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By S Szylkarski, D N. Graham

In mining, water management is an operational necessity, requiring planning and detailed engineering, as well as risk assessment. Yet, the hydrology of streams and aquifers typically extends well beyond the boundaries of mine operations and intersect with environmental and social values. Mine managers often plan, design and assess the impact of water management activities (such as dewatering, excess water disposal and flood management) with a mine site or process specific focus. The challenge is that the impacts are spatial, long-term and complex – and may be cumulative across multiple mine sites. Further, there is usually little consideration of the feedbacks and interactions between surface water, groundwater and catchment hydrology. Failure to understand these processes can lead to poor decisions and increased costs. This presentation outlines an approach to simulating integrated hydrology in mining catchments that addresses the shortcomings of traditional modelling techniques.CITATION:Graham, D N and Szylkarski, S, 2016. Simulating integrated hydrology in mining catchments from planning to closure, in Proceedings Life-of-Mine 2016 Conference, pp 101–105 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By B Belle

"Mines around the world are inherently and operationally diverse. Current methodologies for the design of mine ventilation and cooling infrastructure involve controlling major safety and health hazards. Globally, it can be estimated that mine ventilation systems from various commoditiescirculate over 150 000 m3/s of exhaust air through shafts. Additionally, over 2 000 000 workersare transported every day through shafts in labour-intensive mining countries like China, India,Southern Africa, and the Americas. A key objective of this paper is to share experiences and provide a case for the revision of ætime-honouredÆ ventilation design parameters based on a benchmarking exercise on design exhaust shaft velocity from various global operations (gold, diamond, platinum, coal and base metals). An active fi eld observation on exhaust shaft velocity has indicated that, regardless of the commodity or continent where the mine operates, almost all life-of-mine (LOM) design parameters provided are in the same range of 20 m/s to 22 m/s, which is not convincing considering signifi cant variations exist in shaft depths, geography, commodity, operating and capital costs. From a due diligence perspective, there are no documented views that are available on the most widely used design exhaust air velocity. Based on the global exhaust shaft velocity data, it is noted that a significant portion of shaft velocities are outside the current design velocity of 20 m/s (some operating up to 30 m/s) and other signifi cant portions of the exhaust shafts operate in the critical velocity range. In the case of Australian coal mines, limited data suggests that none of the mines have ever reached the LOM design exhaust shaft velocity. It is self-evident that when the shafts are not operating at their design quantities either the mine system resistance is low or the ventilation and main fan is operating ineffi ciently. The most common reasons given for not reviewing the shaft system were, ætime-honouredÆ design parameter are being used and cannot be changed, mine fan pressure limits, possible fan blade damage, possible spontaneous combustion risks, leakage or simply did not consider such a possibility. In conclusion, the study has reiterated the historic lessons that a safe and expensive airway should not be utilised uneconomically by circulating too litt le air through it."

Jun 1, 2012

By R Rimmelin, C Vergara

Heap leach pads are composed of mined ore, usually crushed, disposed on liners to be processed with leach solutions, and the tail of the process is called “spent ore” which are then transported by conveyor belts to be disposed into dumps. It is often to observe stability problems in these dumps, that could affect the equipment working on it and the continuity of the whole mine process. These problems are related to an excess of water content at the spent ore, therefore the operational efforts are focused onto control this geotechnical parameter.This work presents the results of different geotechnical laboratory testing, using samples of spent ore of a mining operation in the north of Chile. In the last 10 years, 3 campaigns have been made to get samples. Valuable information was obtained to identify how specific operational/metallurgical factors could affect the geotechnical behaviour of the spent ore. Special attention is given to the decision to change the metallurgical process adding salt to the heap leach process and its impact to its hydraulic conductivity.Historically, the process has been based on the leaching of oxides and sulphides materials, in separate campaigns, in which it is possible to observe different geotechnical response in the spent ore generated. Recently, it was implemented a new process in which the materials are blended and salt is added, to improve metallurgical performance in terms of recovery. This change generate impacts in the dump, since the geotechnical parameters are affected; decreasing hydraulic conductivity in about one order of magnitude (explained by the salt added).Changes are shown in the geotechnical parameters of the spent ore, considering that the mining source is the same, and how the operational process and dump design are affected.CITATION:Rimmelin, R and Vergara, C, 2018. Geotechnical behaviour of spent ore – impacts of metallurgical factors, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 369–375 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By J C. Koppe, L Vieira

One common problem for blasting in iron ore mines with significant weathering is the occurrence of large blocks of hard rock mixed with softer material. This situation causes a problem for blasting design and sometimes produces large boulders of rock that require a secondary blasting, as well as excavation difficulties. To minimise this situation, geophysical techniques were used to identify the hardest material amid the weathered material. To study the problem, seismic, ground penetrating radar (GPR), electrical resistivity and induced polarisation (IP) methods were used in an intensely weathered Brazilian iron ore deposit. The methods of GPR combined with IP, resistivity and seismic showed to be effective in modelling the contrast among hard, friable materials and soil. The results were used to improve the geological model and create more favourable conditions for the subsequent blast design. The blast design based on geophysical/geological models resulted in significant improvement in the fragmentation of the iron ore. This was achieved by the adoption of a specific drilling pattern for a given geological situation. With the new specialised blasting design the formation of boulders was eliminated.CITATION:Vieira, L and Koppe, J C, 2015. Geophysical techniques applied to blasting design, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 289–294 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The BHP Billiton Cannington mine uses sequential flotation to treat a silver, lead and zinc ore supplied from an underground mine. The final products from the process plant are a silver rich lead concentrate and a zinc concentrate. Operational history of plant performance highlighted that the majority of valuable metal losses to final tailing occurred in the -5 ¦m fraction. Research completed on the flotation characteristics of this size fraction in plant feed resulted in the development of a split flotation process to improve the silver and lead mineral recoveries. Construction of a $A 9.5 million brownfield project to install the new split flotation circuit at Cannington was completed in July 2002. The circuit consists of three stages of cyclone classification to recover the ultra fine material to a final cyclone overflow stream, conditioning of this pulp to achieve optimal process conditions, and conventional rougher and three stage cleaner flotation to produce a silver rich lead concentrate. The rougher tail from the new circuit is recombined with the cyclone underflow streams and processed through the original lead-zinc flotation circuit. This paper discusses the circuit design, material properties, material selection for components of the circuit, operational practices and requirements to ensure the circuit succeeded in meeting production targets. The technology is subject of a number of patent applications including international application No PCT/AU02/00400.

Jan 1, 2003

By J Robertson, D Williams, H D. Plewes

The co-mixing of tailings and waste rock involves the intimate blending of tailings and waste rock to create a new material (Co-Mix) with superior physical and hydraulic properties. The new material has a low hydraulic conductivity, low compressibility, high water retaining capacity and high shear strength. Co-mixed tailings and waste rock restrict oxygen entry and water seepage to minimise acid generation and metal leaching. When compacted, Co-Mix materials have low volume change characteristics with respect to total stress and matric suction together with high shear strength. Co-mixed tailings and waste rock may be used to construct cover systems, internal barriers and seals, confinement structures or a full depth waste repository. The theoretical properties of Co-Mix blends are investigated. The results of a laboratory program to characterise the physical and hydraulic properties of co-mixed tailings and waste rock are presented. Various ratios of tailings were blended with different waste rock materials. Hydraulic conductivity tests were conducted at confining pressures ranging between 0 and 400 kPa. The saturated hydraulic conductivity for the Co-Mix materials was found to vary between 4 + 10-5 m/s and 5 + 10-9 m/s depending on blend ratio, waste rock type and confining pressure. These results together with other physical properties show excellent hydraulic and strength characteristics can be achieved for Co-Mix materials.

Jan 1, 2003

The Coal Section of the Geological Survey of Queensland was formed in 1950 to plan and supervise systematic diamond drilling programmes to investigate the State's coal resources. For the first 15 years these programmes were con- fined to the established coalfields to prove reserves of coal suitable for steam raising for power generation. Adequate reserves were del- ineated during this period to provide coal for the operating lives of new power stations at Ipswich and Collinsville. Later exploration was aimed at a regional appraisal of coal mea- sure stratigraphy, particularly in the Bowen and Galilee Basins. This was followed, in some areas, by drilling to prove reserves to indic- ated status. Parameters were developed to allow a uniform approach to the estimation of reserves. Coal quality is evaluated in terms of potential utilization of coal. Reserves defined by exploration companies are assessed, and combined with reserves from Departmental drilling into a general table. Total reserves in situ amount to 9 962 million tonnes of coking coal and 7 333 million tonnes of non-coking coal. Approximately 20 per cent of coking and 40 per cent of non-coking coal were proved as a direct result of Geological Survey drilling programmes. Further explor- ation is planned for the Bowen and Galilee Bas- ins and may extend to the Surat Basin.

Jan 1, 1977

Current problems in predicting sub-surface strata movement and fracture development due to longwall mining have highlighted the need for more accurate, dependable methods of physical modelling of rock mechanics problems which are beyond the capabilities of current mathematical techniques. Physical model studies of the caved zone above the working faces up to the base of a water source are of importance in attempting to understand changes in mass permeability due to induced fracture zones and the resulting ground water conditions. Turkey's most important supplies of coking coals are to be found within the hard coal resources of the Black Sea coast. Coal seams up to 9 metres thick, dipping at angles as steep as 90 degrees are being successfully mined at the Kozlu Mine. Since 1956, mining operations have been carried out under the sea in dry conditions. The undersea mining conditions of the Kozlu Mine have been investigated using scaled physical models constructed from artificial materials which satisfied necessary scaling requirements. Models representing the in-situ conditions were tested and the following extraction sequence was employed: 1. The Sulu Seam extraction 2. The Acilik Seam extraction (as two slices) 3. The Piric Seam extraction. The displacement of the fixed reference points were subsequently measured using a high precision photogrammetric technique and induced horizontal and vertical strains were calculated.

Jan 1, 1988

By D Kent, R Paine

"Automated mining systems are increasingly being seen as a key requirement for a productive mining operation in the future. The importance of an integrated communication network infrastructure to support such systems is growing.This paper outlines the introduction of automated mining systems in large conventional mines as well as their growing role in block cave mines currently operating or being developed. The paper will then focus on a case study of how the communication infrastructure is fundamental to the operation of such systems and explain why the resultant communication networks require much more than just increased bandwidth (data capacity) to properly support the automation system within the overall mine operation.Mining operations already embarking down this road are discovering that the required network must be based on a true enterprise level architecture to not only enable the mine’s current plans for remote and automated mining, but also provide a scalable and integrated platform for future developments and requirements. The emerging issues for the communication network to truly support automation systems include: increased complexities of operating and maintaining multiple networks integration issues with disparate systems problems with reporting particularly as demands for corporate reporting and compatibility with enterprise systems become the norm ongoing management challenges, which will only increase with the proliferation of new technologies.The paper will explore how certain mining operations are addressing this by adopting a long-term strategy for automation deployment, which includes laying the necessary foundation architecture to meet their current requirements, while supporting their future visions for the fully automated mine.CITATION:Paine, R and Kent, D, 2014. Developing the foundation communication infrastructure to support remote and automated mining initiatives in underground mines, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 151–158 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By Bicer N

Current problems in predicting sub-surface strata movement and fracture development due to longwall mining have highlighted the need for more accurate, dependable methods of physical modelling of rock mechanics problems which are beyond the capabilities of current mathematical techniques. Physical model studies of the caved zone above the working faces up to the base of a water source are of importance in attempting to understand changes in mass permeability due to induced fracture zones and the resulting ground water conditions. Turkey's most important supplies of coking coals are to be found within the hard coal resources of the Black Sea coast. Coal seams up to 9 metres thick, dipping at angles as steep as 90 degrees are being successfully mined at the Kozlu Mine. Since 1956, mining operations have been carried out under the sea in dry conditions. The undersea mining conditions of the Kozlu Mine have been investigated using scaled physical models constructed from artificial materials which satisfied necessary scaling requirements. Models representing the in-situ conditions were tested and the following extraction sequence was employed: 1. The Sulu Seam extraction 2. The Acilik Seam extraction (as two slices) 3. The Piric Seam extraction. The displacement of the fixed reference points were subsequently measured using a high precision photogrammetric technique and induced horizontal and vertical strains were calculated.

Jan 1, 1988