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Application Of Smartshear To Define Rock Mass Shear About Coal Mine Roadways, Benjamin Blacka, Stuart Macgregor, Adrian Rippon, Michael Melville, Graham Wylie, Anne Wylie
Application Of Smartshear To Define Rock Mass Shear About Coal Mine Roadways, Benjamin Blacka, Stuart Macgregor, Adrian Rippon, Michael Melville, Graham Wylie, Anne Wylie
Resource Operators Conference
Shear movement of strata surrounding excavations is a critical factor in overall excavation stability. Understanding the location, timing, magnitude and direction of shear failure surrounding an excavation is useful for assessing primary and secondary roadway support requirements. A new routine shear monitoring instrument known as the SmartShear has been developed to accurately measure shear movement at multiple locations within a borehole. The shear movement is measured on a two dimensional plane at 90 degrees to the installation of the instrument using a series of tiltmeter sensors. Continual change in shear direction and magnitude over time is measured once the shear …
Performance Analysis Of Surface Goaf Gas Drainage Holes For Gas Management In An Australian Coal Mine, Bharath Belle, Guangyao Si
Performance Analysis Of Surface Goaf Gas Drainage Holes For Gas Management In An Australian Coal Mine, Bharath Belle, Guangyao Si
Resource Operators Conference
ABSTRACT: This paper focuses on assessing gas drainage performance from vertical surface goaf holes in an operating mine with high specific gas emission rates (~20 m3/t). Field monitoring results of gas flow rate and gas composition collected from individual gas drainage holes were analysed. The major challenge of implementing the full potential of goaf drainage system is the perceived risk of spontaneous combustion (sponcom) in goaf using arbitrary trigger set points. Although the provenance on the introduction and reasons for the use of CO is unknown, the paper highlights that the current use of CO based trigger action response plan …
Palaeodepositonal Conditions And Hydrocarbon Source Characteristics Of Lignites From Bikaner-Nagaur Basin (Rajasthan) Western India Based On Organic Petrographic Studies, Umar Farooq, Rimpy Chetia, Runcie Mathews, Shalivahan Srivastav, Bhagwan Singh, Vikram Singh
Palaeodepositonal Conditions And Hydrocarbon Source Characteristics Of Lignites From Bikaner-Nagaur Basin (Rajasthan) Western India Based On Organic Petrographic Studies, Umar Farooq, Rimpy Chetia, Runcie Mathews, Shalivahan Srivastav, Bhagwan Singh, Vikram Singh
Resource Operators Conference
ABSTRACT: In Indian subcontinent Cenozoic lignites are found at several places along the boundary of Indian plate which was the shoreline of palaeotethys. However, the western part of the Indian subcontinent is particularly rich in lignites and shales along with hydrocarbon reserves. Thus, this location of the country is an important producer of hydrocarbon and lies at a significant position in the mineral map of the country. In the north western state of Rajasthan, lignites are reported in associated with the Cenozoic sedimentary rocks extending an area of 70,000 sq.kms in Bikaner, Barmer, Nagaur, Jalore and Jaisalmer districts. The present …
A Review Of The Mechanics Of Pillar Behaviour, Kenneth William Mills
A Review Of The Mechanics Of Pillar Behaviour, Kenneth William Mills
Resource Operators Conference
In recent years, the drive to reduce the impacts of surface subsidence has led to mine layout designs that rely for their effectiveness on the long-term stability of pillar systems. This paper reviews the mechanics of coal strength behaviour inferred from laboratory testing of coal specimens as a context to better understand the appropriateness of different pillar design strategies. Laboratory testing of coal specimens to very high confining pressures (163 MPa) illustrates the independence of the two fundamental components of coal strength: cohesive strength and frictional strength. Testing of numerous coal samples from the same coal seam and coal samples …
Shear Strength Of Rock Joints Under Constant Normal Loading Conditions, Ali Mirzaghorbanali, Faisel Alenzel, Peter Gregor, Naj Aziz, Kevin Mcdougall, Andreas Helwig
Shear Strength Of Rock Joints Under Constant Normal Loading Conditions, Ali Mirzaghorbanali, Faisel Alenzel, Peter Gregor, Naj Aziz, Kevin Mcdougall, Andreas Helwig
Resource Operators Conference
The variation of shear strength of rock joints under constant normal loading conditions was studied. Three dimensional printing technology was incorporated to produce moulds of rock joints. Rock joints samples with three different roughness values were cast using concrete with uniaxial compressive strength of 20 MPa. Samples were sheared using a direct shear testing machine for normal stress values ranging from 0.25 to 0.7 MPa. In addition, effects of shear rate on shear strength properties of rock joints were experimentally investigated. It was found that the shear strength of rock joints is a function of normal stress, joint roughness and …
Application Of Computer Aided Engineering Techniques In Combination With High-Energy Dust Suppression Technology For The Handling Of Coal, Jon Roberts, Michael Hopkins, Peter Wypych, Vitold Ronda
Application Of Computer Aided Engineering Techniques In Combination With High-Energy Dust Suppression Technology For The Handling Of Coal, Jon Roberts, Michael Hopkins, Peter Wypych, Vitold Ronda
Resource Operators Conference
The coal industry faces significant challenges in the control of dust to meet emissions regulations and goals as well as ensuring sustainable operations. This paper describes some of the different techniques and innovative technologies that are being developed and implemented to improve the suppression of airborne dust, specifically through the use numerical modelling in combination with high-energy micro-mist sprays. In the handling of coal, ROM bin loading, transfer points, and discharge to stockpiles are identified as common and significant sources of dust, specific industry examples are presented. To tackle these areas, the utilisation of CFD and CFD-DEM simulation modelling is …
Numerical Investigations Of Infilled Joint Shear Under Different Lateral Boundary Confinement Conditions, Libin Gong, Jan Nemcik, Ting Ren
Numerical Investigations Of Infilled Joint Shear Under Different Lateral Boundary Confinement Conditions, Libin Gong, Jan Nemcik, Ting Ren
Resource Operators Conference
Direct shear is one of the most common laboratory testing methods to study the shear behaviour of infilled rock joints. One of the major concerns is the boundary conditions of infill material in the shear direction, or in other words the “lateral confinement” conditions of the infill layer. In this paper, the effects of various infill lateral confinement conditions on the joint shear behaviour were investigated in the software FLAC. It was found that the interface slip patterns, shear band distribution, and the variations of shear stress and lateral confining stresses, are all dependent on the selected lateral conditions. To …
The Limitations And Potential Design Risks When Applying Empirically-Derived Coal Pillar Strength Equations To Real-Life Mine Stability Problems, Russell Frith, Guy Reed
The Limitations And Potential Design Risks When Applying Empirically-Derived Coal Pillar Strength Equations To Real-Life Mine Stability Problems, Russell Frith, Guy Reed
Resource Operators Conference
Determining coal pillar strength equations from databases of stable and/or failed case-histories is more than 50 years old and has been applied in different countries by different researchers in a range of mining situations. Whilst common wisdom sensibly limits the use of the resultant pillar strength equations and methods to design scenarios that are consistent with the founding database, there are a number of examples whereby failures have occurred as a direct result of applying empirical design methods to coal pillar design problems that are inconsistent with the founding database. The paper explores the reasons as to why empirically-derived coal …
Roadways Development And Monitoring Within Deep Coal Mines In The Czech Republic, Radovan Kukutsch, Petr Waclawik, Jan Nemcik
Roadways Development And Monitoring Within Deep Coal Mines In The Czech Republic, Radovan Kukutsch, Petr Waclawik, Jan Nemcik
Resource Operators Conference
Use of the system of dual-use of gateroads represents a significant change in the hitherto preferred method of addressing of mining works development. The entire system is based on the principle of reuse of one gateroad during the process of mining of the pair of neighbouring mining panels. The basic condition for its possible application is the stability of the supporting reinforcement of the gateroad so as for it to be able to withstand the additional loads originating in conducting longwalls or other expected supplementary loads to ensure the stability of the mine working throughout its required service life. Sufficient …
Development Of Double Shear Testing Of Tendons, Naj Aziz, Guanyu Yang, Saman Khaleghparast, Travis Marshall
Development Of Double Shear Testing Of Tendons, Naj Aziz, Guanyu Yang, Saman Khaleghparast, Travis Marshall
Resource Operators Conference
More than 25 years of uninterrupted research on ground support technology for underground mines has been undertaken at the University of Wollongong. This research has resulted in significant findings on tendon characteristics and strength properties. The paper focuses on the development of a fourth generation of cylindrically shaped shear test apparatus for assessing tendon performance in shear. This shear apparatus is known as the MK-IV Double Shear Box or Naj Aziz Double Shear Box (NADSB), and is based on the experience gained from the development of previous versions of rectangular double shear boxes. The new NADSB is circular in shape …
Strength Properties Of Grout For Strata Reinforcement, Ali Mirzaghorbanali, Peter Gregor, Zainab Ebrahim, Abdullah Alfahed, Naj Aziz, Kevin Mcdougall
Strength Properties Of Grout For Strata Reinforcement, Ali Mirzaghorbanali, Peter Gregor, Zainab Ebrahim, Abdullah Alfahed, Naj Aziz, Kevin Mcdougall
Resource Operators Conference
Past studies on the mechanical properties of grout were critically investigated and classified. Grout samples were cast using a specially designed dog bone mould. Effects of curing time on tensile strength properties were investigated, using a universal tensile testing machine for curing times intervals ranging from 1 to 28 days. In addition, various percentages of fly ash were added to cube grout samples. Fly ash mixed samples were cured for different curing times and subsequently subjected to Uniaxial Compression Testing (UCS). It was found that tensile resistance of grout samples increased with respect to curing time. Moreover, it was concluded …
How Blocked Gas Detectors Change The Apparent Concentration Of Gas, Ian Webster
How Blocked Gas Detectors Change The Apparent Concentration Of Gas, Ian Webster
Resource Operators Conference
The operation of a diffusion type gas detectors used in fixed, machine mounted and handheld applications is reliant on the natural equalisation of dissimilar gas concentrations driven by partial pressures inside and outside the detector. Typically, this equalisation is inhibited (to a greater or lesser degree) by protective filters and barriers surrounding the fragile sensing elements from the typically harsh ambient environments. The accumulation of dust and other foreign matter on the protective filters can further inhibit the diffusion of gas into a detector. The usual calibration process for a gas detector – typically by a ‘bump’ or ‘challenge’ test …
A Scientific Approach To Quantifying The Efficiency And Efficacy Of Dust Curtains On A Sandvik Mb650 Continuous Miner At Kestrel Colliery Whilst Mining A Full Face Of Roof Stone During An Overcast Construction, Brian Plush, Bradley Watson, Clinton Daly, Timothy Gooch, Charlie Spence
A Scientific Approach To Quantifying The Efficiency And Efficacy Of Dust Curtains On A Sandvik Mb650 Continuous Miner At Kestrel Colliery Whilst Mining A Full Face Of Roof Stone During An Overcast Construction, Brian Plush, Bradley Watson, Clinton Daly, Timothy Gooch, Charlie Spence
Resource Operators Conference
With the correct identification and continued increase in CWP and related occupational lung disease in the Australian coal mining industry since May 2015, the industry’s focus has been directed at mining operations achieving statutory respirable dust level compliance to AS2985. The majority of dust control techniques currently installed and operational in Australian coal mines have been developed in the USA, UK and other western countries and their application is more suited to low to medium coal seam heights up to 3m. The Australian mining experience has indicated that the efficiency of some of the existing respirable dust control methods reduce …
Developing And Using Empirical Models For Geotechnical Design In Underground Coal Mining, Mark Colwell
Developing And Using Empirical Models For Geotechnical Design In Underground Coal Mining, Mark Colwell
Resource Operators Conference
This paper addresses several historical and contemporary issues that relate to the various modelling and analysis techniques utilised in the Australian underground coal industry to assist in geotechnical design and in particular ground support design, while focussing on the development and use of empirical techniques, which have substantially contributed to improving safety and productivity both in Australia and overseas. In the field of mining geotechnics, the potential experience base is huge. For example many longwall panels are mined each year, and each one is a full-scale test of a pillar design and the ground support system(s) employed. The basic approach …
Assessment Of Development Roadway Roof Conditions At An Operating Underground Coal Mine Using Neural Network Analysis, Stephen Geise, Jason Emery, Ismet Canbulat
Assessment Of Development Roadway Roof Conditions At An Operating Underground Coal Mine Using Neural Network Analysis, Stephen Geise, Jason Emery, Ismet Canbulat
Resource Operators Conference
Considering that the majority of Australian longwall mines are currently roadway development constrained, understanding of the key geotechnical parameters that determine the roadway roof behaviour is often critical to the success of modern longwall operations. Crucial to improving this understanding is geotechnical characterisation. This process typically evolves with time and experiences at any underground coal mine and is necessary to understand the variation of the rock mass across a mining area. Based on local experience it is possible to improve forecasting of how similar geotechnical areas will behave and subsequently, the types and densities of support required to maintain roadway …
Numerical Simulation Of Stress Distribution In Longwall Panels During The First Caving Interval, Sadjad Mohammadi, Mohammad Ataei, Reza Kakaie, Ali Mirzaghorbanali, Naj Aziz, Ashkan Rastegarmanesh
Numerical Simulation Of Stress Distribution In Longwall Panels During The First Caving Interval, Sadjad Mohammadi, Mohammad Ataei, Reza Kakaie, Ali Mirzaghorbanali, Naj Aziz, Ashkan Rastegarmanesh
Resource Operators Conference
Reliable prediction of induced stress distribution in longwall panels enhances safety in longwall mining. This paper presents the results of numerical simulation intended to examine stress distribution in terms of peak abutment pressures during the first caving of longwall mining. Longwall mining was simulated by incorporating Universal Distinct Element Code (UDEC). Several conceptual models were developed and subsequently analyzed to investigate the effects of five critical parameters on peak abutment pressures. Critical parameters that were studied as a part of this investigation included roof strata uniaxial compressive strength, immediate roof height, spacing of bedding planes and Vertical and horizontal in …
Proceedings Of The 2019 Coal Operators Conference, Naj Aziz, Bob Kininmonth
Proceedings Of The 2019 Coal Operators Conference, Naj Aziz, Bob Kininmonth
Resource Operators Conference
Proceedings of the 2019 Coal Operators Conference. All papers in these proceedings are peer reviewed. ISBN (ebook): 978-1-74128-303-7 ISBN (paperback): 978-1-74128-304-4.
Digital Twin Based Method To Monitor And Optimize Belt Conveyor Maintenance And Operation, Manfred Ziegler
Digital Twin Based Method To Monitor And Optimize Belt Conveyor Maintenance And Operation, Manfred Ziegler
Resource Operators Conference
The presentation is about a newly, developed method to monitor and optimize belt conveyors, based on a high precision reproduction of the conveyor behaviour using a digital twin. By this numerical reproduction and the continuously performed synchronization between calculation and measuring, the system achieves an unmatched transparency of the belt conveyor’s actual condition. Besides precise information about the overall efficiency, the system delivers early warnings about any changings of the physical state of the conveyor. The generated data allows analysis about time, place and root cause of the changes as well as quantitative statements about the operational properties of the …
Intermediate Drive Technology As A Cost-Saving Solution For Belt Conveyor Upgrades, Blake Burgeth
Intermediate Drive Technology As A Cost-Saving Solution For Belt Conveyor Upgrades, Blake Burgeth
Resource Operators Conference
The demand on belt conveyors continues to increase. Availability and reliability are key factors for increased productivity. Linear booster drives for mining conveyors were initially used in the US in the 1980-90’s with marginal success. The primary issue of this technology was controlling and transferring the power to the belt. Voith has successfully applied linear booster drives to over 300 installations worldwide. The Voith TurboBelt “TT Linear Booster Drive”, is optimized in a complex engineering process to meet the customers’ targets. Linear booster drives can save 25% or more on both Capex and Opex costs. This paper highlights the advantages …
The Development Of A Novel Backfilling Technology: Concept And Behaviour, Lihai Tan, Ting Ren, Xiaohan Yang
The Development Of A Novel Backfilling Technology: Concept And Behaviour, Lihai Tan, Ting Ren, Xiaohan Yang
Resource Operators Conference
A novel backfilling method for underground coal mines has been recently proposed at the University of Wollongong. Different from traditional backfilling technology (i.e. solid backfilling and paste backfilling), the main feature of this technology is that cementitious material with high water-to-solid ratio is directly pumped into the gob filled with coal reject aiming to fill the large number of voids. To verify the feasibility and potential advantages of this new technology compared to its counterparts, a series of compression tests have been conducted. A total of four cubic samples with the dimension of 300 mm and the height of 150 …
Assessment Of Key Parameters On Load Transfer During Development Of A Spin-To-Stall Resin Bolt System, Kent Mctyer
Assessment Of Key Parameters On Load Transfer During Development Of A Spin-To-Stall Resin Bolt System, Kent Mctyer
Resource Operators Conference
BOLT SYSTEM Kent McTyer1 ABSTRACT: Spin-to-stall resin bolting system originated in the late 1990’s at South Africa’s Goedehoop Colliery and has become accepted over recent years in Australian underground coal mines. The main benefit touted is a simplified installation procedure that can lead to both reduced bolting cycle times and more consistent installation quality. These benefits are consistent with mining industry requirements of greater overall efficiencies – especially in mine roadway development rates. Traditional pre-tensioned resin bolting practice has employed a bolt-rotation stoppage, or hold time, to allow the fast-set resin anchor to fully cure before re-starting rotation to pre-tension …
Why The Peak Shear Load Of Indented Cables Increases With Increased Wire Failures?, Guanyu Yang, Saman Khalegparast, Naj Aziz, Jan Nemcik, Travis Marshall
Why The Peak Shear Load Of Indented Cables Increases With Increased Wire Failures?, Guanyu Yang, Saman Khalegparast, Naj Aziz, Jan Nemcik, Travis Marshall
Resource Operators Conference
In shear testing of indented cables it has been found that indented cables peak share load failures behave contrary to the normal failure behaviour. The gradual strength loss with each individual wire failure in an indented cable strand may not lead to subsequent peak shear failure of the remaining strands in decline. This failure behaviour is characteristic of indented cables and occurs irrespective of the test method used (single shear or double shear test). Accordingly in this study all wires in a tested cable strand were instrumented with strain gauges. Each instrumented wire was individually colour coded to assist in …
Field And Simulation Study For Rock Bolt Loading Characteristics Under High Stress Conditions, Petr Waclawik, Sahendra Ram, Ashok Kumar, Radovan Kukutsch, Adam Mirek, Jan Nemcik
Field And Simulation Study For Rock Bolt Loading Characteristics Under High Stress Conditions, Petr Waclawik, Sahendra Ram, Ashok Kumar, Radovan Kukutsch, Adam Mirek, Jan Nemcik
Resource Operators Conference
Rhomboid shaped coal pillars (35 m x 30 m to 26 m x16 m) were formed by a modified Room and Pillar method below 850 m depth from surface at the CSM mine in the Czech Republic. The pillars were developed in a shaft protective pillar by driving roadways of 3.5-4.5 m in height and 5.2 m in width within Panel V of Seam No. 30. Development of pillars at such great depth is prone to spalling/fracturing (pillar rib dilation) due to redistribution of the high stress regime. The induced stress driven dilation was measured during partial extraction of the …
Over-Core Recovery Of A Drill String Bogged In A Longhole, Frank Hungerford, Mitch Fagan
Over-Core Recovery Of A Drill String Bogged In A Longhole, Frank Hungerford, Mitch Fagan
Resource Operators Conference
Underground in-seam directional drilling regularly encounters zones of unstable strata. In some cases, borehole collapse leads to the bogging of the drill string. With the high cost of in-hole equipment at risk and the likely loss if not recovered at the time, over-coring has become an established form of recovery. Due to in-hole friction of the over-core rods with the borehole and the bogged rods exacerbated by the deviations within a directionally drilled borehole, the depths from which over-core recovery has been successful has been limited. This paper explains the prior installations, precautions, considerations and procedures employed for a successful …
Application Of Ventsim To Low Pressure Gas Drainage And High Pressure Nitrogen Reticulation Systems, Roy Moreby
Application Of Ventsim To Low Pressure Gas Drainage And High Pressure Nitrogen Reticulation Systems, Roy Moreby
Resource Operators Conference
This paper outlines a methodology employed to apply Ventsim ventilation modelling software to gas drainage and nitrogen injection systems. Use of the software to account for compressible flow, specified gas compositions and the resistance of conduits of various dimensions makes it suitable for both ventilation circuits and gas reticulation systems. Unlike mine ventilation circuits, in gas drainage systems it is necessary to specify flow rates arising from gas pre drainage holes as these are dependent on gas reservoir properties. This requires a mass flow balance to be obtained between underground gas drainage holes and that reporting to surface pump(s). In …
Reliable Referencing For Fixed And Machine Mounted Gas Detectors, Ian Webster, Thomas Steigler
Reliable Referencing For Fixed And Machine Mounted Gas Detectors, Ian Webster, Thomas Steigler
Resource Operators Conference
Diffusion type gas detectors are used in fixed, machine mounted and handheld applications in underground mines for the real time detection of flammable and toxic gases. The calibration of a gas detector – typically by a ‘bump’ or ‘challenge’ test – sets the reference against which all subsequent measurements are taken. Failure to properly calibrate a detector will introduce errors into every subsequent measurement, regardless of the claimed accuracy of the instrument. The vulnerability of the calibration process to poor calibration mask design and to ambient air velocities has been established. The real problem, however, is knowing if and how …
Flow Measurement In Gas Drainage, Tim Harvey, Ian Gray
Flow Measurement In Gas Drainage, Tim Harvey, Ian Gray
Resource Operators Conference
This paper reviews the need for flow monitoring in gas drainage and the flowmeters that are available to do this. As suitable flowmeters that are capable of dealing with gas, water and particulate matter do not exist work has been done to adapt ball valves for this purpose. They have been found to fill the function admirably and with a combined manometer and pressure sensor can provide flow ranges in excess of 100:1. They can also be left wide open to avoid blockage when not being used for measurement.
Ageing Effect On The Self-Heating Incubation Behaviour Of Lignite, Basil Beamish, Jan Theiler, Andrew Garvie
Ageing Effect On The Self-Heating Incubation Behaviour Of Lignite, Basil Beamish, Jan Theiler, Andrew Garvie
Resource Operators Conference
A lignite seam present in overburden strata of an opencut mine poses an interesting question as to its spontaneous combustion hazard likelihood when placed into an overburden spoil pile. Lignite is often assumed to rapidly spontaneously combust when exposed to air due to its low rank. However, lignite also has a high moisture content as-mined, generally in the order of 40% or greater. Self-heating is a balancing act between the intrinsic reactivity of the coal and the moisture present, which can act as a moderating influence to the rate of self-heating. In addition, this balance can be altered by ageing …
A Review Of Energy Sources Of Coal Burst In Australian Coal Mines, Xiaohan Yang, Ting Ren, Xuequi He, Lihai Tan
A Review Of Energy Sources Of Coal Burst In Australian Coal Mines, Xiaohan Yang, Ting Ren, Xuequi He, Lihai Tan
Resource Operators Conference
Abstract: Coal burst, which refers to the violent and catastrophic failure of coal, is a serious safety hazard for underground coalmines. Coal burst has attracted intensive research interest from mining and geological scholars. Due to the shallow mining depth, simple geological condition, advanced mining technology and reasonable geotechnical design, coal bursts has not been identified as a safety hazard in Australia coalmines as there are no documented coal bursts cases in Australia before 2014. However, more recently, the coal burst risk in Australian coalmines was highlighted by coal burst accidents in some coalmines. This paper reviewed the potential energy sources …
A Causation Mechanism For Coal Bursts During Roadway Development Based On The Major Horizontal Stress In Coal, Very Specific Structural Geology Causing A Localised Loss Of Effective Coal Confinement And Newtons’ Second Law, Russell Frith, Guy Reed, Aaron Jones
A Causation Mechanism For Coal Bursts During Roadway Development Based On The Major Horizontal Stress In Coal, Very Specific Structural Geology Causing A Localised Loss Of Effective Coal Confinement And Newtons’ Second Law, Russell Frith, Guy Reed, Aaron Jones
Resource Operators Conference
This paper outlines what is considered to be a credible, first-principles, mechanistic explanation for these three current development coal burst conundrums by reference to early published coal testing work examining the significance of a lack of “constraint” to coal stability and an understanding of how very specific structural geology and other geological features can logically cause this to occur in situ, albeit on a statistically very rare basis. This basic model is examined by reference to published information pertaining to the development coal-burst that occurred at the Austar Coal Mine in New South Wales, Australia, in 2014 and from the …