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Shear Strength Properties Of Artificial Rock Joints, Muhammad Zohaib, Ali Mirzaghorbanali, Andres Helwig, Naj Aziz, Peter Gregor, Ashkan Rastegarmanesh, Kevin Mcdougall
Shear Strength Properties Of Artificial Rock Joints, Muhammad Zohaib, Ali Mirzaghorbanali, Andres Helwig, Naj Aziz, Peter Gregor, Ashkan Rastegarmanesh, Kevin Mcdougall
Resource Operators Conference
The shear strength property of artificial rock joints with triangular and sinusoidal roughness was investigated in the laboratory by the aid of direct shear test machine. In particular, this paper includes literature review of past studies on shear strength properties of unfilled and infilled rock joints, experimental studies on shear strength properties of artificial rock joints with triangular, sinusoidal and plain roughness under various normal load and comparison between shear behaviour of these rock joints having different roughness patterns. This research presents the concepts development essential to envision the shear behaviour of rock slopes aided by artificial rock joints. It …
Numerical Model Of Dynamic Rock Fracture Process During Coal Burst, Gaetano Venticinque, Jan Nemcil
Numerical Model Of Dynamic Rock Fracture Process During Coal Burst, Gaetano Venticinque, Jan Nemcil
Resource Operators Conference
Coal bursts present one of the most severe hazards challenging the safe operations in underground coal work environments. In Australia, these events are becoming increasingly frequent as coal measures are mined progressively deeper. This study is supported by the Australian Coal Association Research Program (ACARP) which aims to better understand the phenomena of coal burst. In this paper the dynamic fracture process of coal bursts was successfully simulated in the coal roadway. This was achieved using dynamic analysis utilising DRFM2D routine by Venticinque and Nemcik (2017) in FLAC2D (Itasca, 2015) which complemented previous study observations by Venticinque and Nemcik (2018). …
Impact Of Core Sample Recovery Time On Accuracy Of Gas Content Measurement, Dennis Black
Impact Of Core Sample Recovery Time On Accuracy Of Gas Content Measurement, Dennis Black
Resource Operators Conference
Gas content measurement has a significant impact on mine safety and operational efficiency at many Australian underground coal mines. There is an expectation that reported gas content results are accurate and correctly represent the gas content of the coal seam in the area where the coal samples were collected. The practice of some coal sample testing service providers to add ‘correction’ factors to the measured gas content of coal samples increases the reported gas content to account for assumed loss of gas content due to extended recovery time. The methodology used by one gas testing service provider to establish a …
Determining Coal Directional Mechanical Properties Using True Triaxial Testing Facility, Zhongwei Chen, Mehdi Serati, Mutaz El-Amin Mohmoud
Determining Coal Directional Mechanical Properties Using True Triaxial Testing Facility, Zhongwei Chen, Mehdi Serati, Mutaz El-Amin Mohmoud
Resource Operators Conference
Knowledge of coal mechanical properties and strength is critical in modelling and understanding pillar stability, gateroads stability, gas drainage borehole integrity as well as coal responses to hydraulic fracturing stimulation. However, due to the complexity of coal structures and difficulties in obtaining decent coal specimens, measurements of coal mechanical properties have been limited to the application of traditional triaxial and UCS tests, which in turn has shown adverse influence on the design confidence and reliability in practice. In addition, coal is an anisotropic material and such conventional testing techniques are clearly not capable of directly capturing coal anisotropic features. In …
Design Combined Support Under Arbitrary Impulsive Loading, Faham Tahmasebinia, Ismet Canbulat, Chengguo Zhang, Serkan Saydam, Onur Vardar
Design Combined Support Under Arbitrary Impulsive Loading, Faham Tahmasebinia, Ismet Canbulat, Chengguo Zhang, Serkan Saydam, Onur Vardar
Resource Operators Conference
Rock bolts and cable bolts are usually considered to experience static loads under relatively low-stress conditions. However, in burst-prone conditions, support elements are subjected to dynamic loading. Therefore, it is important to understand cable bolt behaviour under dynamic loading conditions, particularly their energy absorption capacity. Rock bolts and cable bolts as well as steel mesh are widely used as permanent support elements in tunnelling, underground excavations and surface slope stability. This paper aims to determine the amount of the dissipated energy which can be taken into account to design combined yielding supports when subjected to dynamic loading. A ground support …
Parametric Studies Of Cable Bolts Using A Modified Short Encapsulation Pull-Out Test, Danqi Li, Hossein Masoumi
Parametric Studies Of Cable Bolts Using A Modified Short Encapsulation Pull-Out Test, Danqi Li, Hossein Masoumi
Resource Operators Conference
The laboratory short encapsulation pull out test (LSEPT) has been widely accepted as the most efficient method to characterize the mechanical behaviour of cable bolts under axial loading. In this study, a number of LSEPTs was performed on conventional cable bolts including Plain SuperStrand and TG cable bolts using the improved pull out test design. The effects of several parameters including the uniaxial compressive strength (UCS) of confining medium and grout and the borehole diameter on the mechanical behaviour of both cable bolts were investigated. Analysis of Variance (ANOVA) was employed to quantify the contribution of these parameters on the …
Performance Of Bolting Systems In Tension And The Integrity Of The Protective Sleeve Coating In Shear, Naj Aziz, Antoine Schneiderwind, Sina Andanpour, Saman Khaleghparast, Duncan Best, Travis Marshall
Performance Of Bolting Systems In Tension And The Integrity Of The Protective Sleeve Coating In Shear, Naj Aziz, Antoine Schneiderwind, Sina Andanpour, Saman Khaleghparast, Duncan Best, Travis Marshall
Resource Operators Conference
A series of laboratory tests were carried out on sleeved bolt and domed washer plates and nuts to determine; • the tensile strength properties of 24 mm (200 mm core) diameter rock bolts (M24 Bolt), • pull through testing of the bolting system consisting of bolt, domed washer plate and nut integrity, • Integrity of the rock bolt fitted with protective plastic sleeve subjected to shearing. All these tests were carried out on rock bolts and dome washer plates supplied by Dextra / Pretec. Pull testing was carried out in accordance with British Standard (BS 7861.1:2007). It was found that …
Application Of Continuous Mechanical Cutting To Coal Overburden Removal, Isaac Dzakpata, Dihon Tadic, Joji Quidim
Application Of Continuous Mechanical Cutting To Coal Overburden Removal, Isaac Dzakpata, Dihon Tadic, Joji Quidim
Resource Operators Conference
Conventional overburden removal in coal mining is typically achieved using drill and blast. However, drill and blast is a cyclical (or batch) process that has inherent inefficiencies and offers limited opportunities for enabling automation technologies. Existing mechanical rock cutting systems such as surface miners, continuous miners, road headers, impact hammers and tunnel boring style machines are commonly applied in underground excavation environments and also in some mining operations. Most of these technologies are based on pick-based machines, mechanical indentation and hammer impact. A review of industry literature and OEM data indicates that beyond rock strengths of about 40MPa UCS, the …
An Improved Technique For Monitoring Explosibility Of Gases, David Cliff
An Improved Technique For Monitoring Explosibility Of Gases, David Cliff
Resource Operators Conference
Monitoring the potential for explosion in an underground coal mine traditionally centres on using the Coward Triangle, the Hughes Raybould Diagram, the USM explosibility diagram or the Ellicott diagram. None of these allow for analytical trending over time, it is difficult to determine rates of change of gas atmospheres using these techniques and thus predict if and when an atmosphere may become explosive. The Ellicott X Y diagram was an attempt to overcome this, This diagram suffers from the lack of bounds and the absence of an easy way to link the values to the limits of reality eg, fresh …
Gas Monitoring - What We Know So Far, Martin Watkinson, Martin Tsai, Larry Ryan
Gas Monitoring - What We Know So Far, Martin Watkinson, Martin Tsai, Larry Ryan
Resource Operators Conference
Remote gas monitoring started in the early 1960’s when carbon monoxide detectors were used in Germany to monitor spontaneous combustion activity. These systems were modified and used in the United Kingdom in the late 1960’s to proactively monitor the underground atmosphere; the tube bundle systems we know today. Real time methane detectors and carbon monoxide detectors were used in British Coal in the mid 1980’s. Large mines in Australia can have up to 60 tube bundle monitoring points and up to 200 individual gas sensors underground. This paper discusses the development of these systems as well as potential issues relating …
Self-Heating Hazard Investigation Of Conveyor Belt Rubber Fines, Basil Beamish, Jan Theiler
Self-Heating Hazard Investigation Of Conveyor Belt Rubber Fines, Basil Beamish, Jan Theiler
Resource Operators Conference
Conveyor belt fires have often been attributed to the heating of accumulated coal fines beneath the belt structure. However, could it be possible that conveyor belt rubber fines produced from friction of the belt in contact with defective rollers or other parts of the belt structure are a self-heating hazard source? The United Kingdom Health and Safety Executive issued a briefing note in December 2012 on the spontaneous heating of piled tyre shred and rubber crumb. This contained information on laboratory experiments that show rubber crumb and tyre shred are more susceptible to self-heating than cellulosic materials (like hay and …
Health Monitoring Of Mining Conveyor Belts, Shuvashis Dey, Omar Salim, Hossein Masoumi, Nemai Karmakar
Health Monitoring Of Mining Conveyor Belts, Shuvashis Dey, Omar Salim, Hossein Masoumi, Nemai Karmakar
Resource Operators Conference
The paper presents a new methodology for monitoring health conditions of mining conveyor belts using Radio Frequency Identification (RFID) based sensors. The existing monitoring technique is based on simple visual inspections which is quite labor intensive and do not provide accurate health condition of the conveyor belt. The new methodology based on UHF chipped and chipless RFID sensors provides highly sophisticated real-time monitoring schemes for different conveyor belt health parameters such as cracks. When combined with machine learning algorithm-based approach, the proposed technique can detect and predict wear and tear over the entire belt. Simulation results show that the proposed …
Measurement Of In-Situ Coal Cleat Compressibility, Gelber Taco, Alberto Kamenar, Jeff Edgoose
Measurement Of In-Situ Coal Cleat Compressibility, Gelber Taco, Alberto Kamenar, Jeff Edgoose
Resource Operators Conference
This paper presents a new and fast method to measure the in situ coal cleat compressibility in a vertical well. Traditional coal cleat compressibility is measured in a lab using small coal samples placed in a cell for its exposure to methane, temperature, pressure and stress representing the in situ conditions. This test takes about one year to complete, and coal heterogeneity and fragility make selection of representative samples difficult. While testing coals for permeability, borehole storage coefficients up to 100 times larger than expected were observed. This anomaly suggests a coal cleat compressibility effect and provides a foundation to …
The Evolution Of Primary Cable Support At Grasstree Mine, Edward Steed, Jason Emery
The Evolution Of Primary Cable Support At Grasstree Mine, Edward Steed, Jason Emery
Resource Operators Conference
An increasing cover depth within a highly variable bedded and laminated roof, coupled with high level longwall retreat performance has required the evolution of cable support for development roadways at Grasstree Mine. This paper briefly addresses the evolution of cable bolting as primary support at Grasstree and captures in detail the theoretical and practical engineering applied to the most recent iteration of cable support, the Jumbo cable.
Proceedings Of The 2020 Coal Operators Conference, Naj Aziz, Bob Kininmonth
Proceedings Of The 2020 Coal Operators Conference, Naj Aziz, Bob Kininmonth
Resource Operators Conference
Proceedings of the 2020 Coal Operators Conference. All papers in these proceedings are peer reviewed. ISBN (ebook): 978-1-74128-321-1 ISBN (paperback): 978-1-74128-320-4.
The Effect Of Elevated Temperature On Resin-Anchored Rock Bolts, Kent Mctyer
The Effect Of Elevated Temperature On Resin-Anchored Rock Bolts, Kent Mctyer
Resource Operators Conference
Resin-anchored roof bolts are used for primary roof support in all Australian underground coal mines. This popularity is due to a combination of technical performance, installation efficiency and cost. Further, many years of research exists pertaining to the load transfer of resin-anchored bolts. However, the composition of the load transfer medium – the resin anchor – means the resin-anchored bolt system is susceptible to possible degradation if high temperatures are applied. Thankfully, while high temperatures of more than 100°C are uncommon in coal mines, there is a rare event that can cause high sustained temperatures – a coal mine fire. …
A Discussion On Causation Mechanisms For Overburden Bumps As Distinct From Coal Bursts, Russell Frith, Guy Reed, Martin Mackinnon
A Discussion On Causation Mechanisms For Overburden Bumps As Distinct From Coal Bursts, Russell Frith, Guy Reed, Martin Mackinnon
Resource Operators Conference
The entire subject area of micro-seismic events due to stored strain energy, as distinct from gas-driven coal outbursts, can be readily sub-divided into firstly events with their energy source from within the coal seam (termed “bursts”) and secondly, event with their energy source outside of the coal seam in either the overburden and/or floor strata. The reason for sub-dividing micro-seismic events in this manner is that if the causation mechanisms and associated geotechnical conditions are materially different, then effective pre-mining predictions and subsequent operational controls may also differ. Attempting to explain a multitude of micro-seismic event types without consideration of …
Fibre Reinforcement Shotcrete In Coal, Barry Sturgeon
Fibre Reinforcement Shotcrete In Coal, Barry Sturgeon
Resource Operators Conference
Fibrecrete Reinforced Shotcrete (FRS), a cement-based mixture pneumatically applied at a high velocity onto coal surfaces. The material component of shotcrete is essentially cement and fly ash blend in a mixed powder form combined with sand, gravel and water. This wet process of shotcrete application is unique to coal, but has been used in the civil industry and hard rock mines for many years. This process allows a good compaction of applied ground support liner that allows penetration into the strata giving a bonded liner with stability, compared to cast-in-place concrete. The advantages of the shotcrete process are related to …
Floor Heave Monitoring Using Floor Instrumentation, Sungsoon Mo, Peter Yee, Terri O'Sullivan, Hossein Masoumi, Ismet Canbulat, Serkan Saydam
Floor Heave Monitoring Using Floor Instrumentation, Sungsoon Mo, Peter Yee, Terri O'Sullivan, Hossein Masoumi, Ismet Canbulat, Serkan Saydam
Resource Operators Conference
Several underground coal mines in Australia have recently reported and anticipated significant floor heave in gateroads during longwall retreat. Floor heave on longwall retreat is typically attributed to a stress notch. To further understand the mechanisms of floor heave, in situ floor heave monitoring was conducted using floor instrumentation at two coal mines. This paper provides the field monitoring results along with the process of selecting the instruments and monitoring sites. To grasp the whole picture of the deformation of floor strata, the instruments for both the vertical and horizontal movements of floor units were considered. For the horizontal floor …
Longwall Behaviour In Massive Strata, Ian Gray, Tim Gibbons
Longwall Behaviour In Massive Strata, Ian Gray, Tim Gibbons
Resource Operators Conference
Longwall mining of coal below massive strata now has a 50 year history, and much of it has been problematic. For the first 30 years, there was much experimentation, with some successes, and many failures due to lack of understanding about how such massive strata behaves during caving, and how this differs from the more conventional and successful longwall mining beneath softer strata, which caves readily. This has been compounded over the last 20 years as mines extract wider faces and thicker seams in a single pass, often at quite shallow depths. Today, China is leading the way with thick …
A Roof Cavability Classification System And Its Use For Estimation Of Main Caving Interval In Longwall Mining, Sodjad Mohammadi, Mohammad Ataei, Reza Kakaie, Ali Mirzaghorbanali, Zahra Faraji Rad, Naj Aziz
A Roof Cavability Classification System And Its Use For Estimation Of Main Caving Interval In Longwall Mining, Sodjad Mohammadi, Mohammad Ataei, Reza Kakaie, Ali Mirzaghorbanali, Zahra Faraji Rad, Naj Aziz
Resource Operators Conference
Proper strata caving in longwall mining guarantees the success of the operation while delayed or poor caving will lead to severe consequences. Therefore, the reliable prediction of strata and its caving potential is essential during the planning stage of a longwall project. This paper reports a novel classification system to evaluate the cavability level of the immediate roof strata in coal mines. A Fuzzy integrated multi-criteria decision-making method was used to incorporate nine inherent parameters that control the caving behaviour. After the determination of parameters’ weights and assigning corresponding ratings, the Cavability Index (CI) was defined as the summation of …
A Review Of Overburden Fracturing And Changes In Hydraulic Characteristics Due To Longwall Mining, Hadi Nourizadeh, Ismet Canbulat, Joung Oh, Chengguo Zhang, Naj Aziz, Ali Mirzaghorbanali, Kevin Mcdougall
A Review Of Overburden Fracturing And Changes In Hydraulic Characteristics Due To Longwall Mining, Hadi Nourizadeh, Ismet Canbulat, Joung Oh, Chengguo Zhang, Naj Aziz, Ali Mirzaghorbanali, Kevin Mcdougall
Resource Operators Conference
Longwall mining is a major mining method to extract thick, flat-lying and extensive seams. Due to the nature of this mining method, the overlying strata move continuously downwards into goaf and as a result, surrounding rocks are distressed, deformed and fractured. In the near area above the mined coal seam, both vertical and horizontal fracturing networks are evident, however within the higher zones, bed separation and slippage are the dominant displacements. The enhanced cracks alter hydraulic characteristics (porosity and permeability) of the rock mass, consequently disturbing the groundwater and surface water flow regime. There have been various techniques utilised to …
Static And Dynamic Testing Of Tendons, Saman Khaleghparast, Sina Anzanpour, Naj Aziz, Alex Remennikov, Ali Mirzaghorbanali
Static And Dynamic Testing Of Tendons, Saman Khaleghparast, Sina Anzanpour, Naj Aziz, Alex Remennikov, Ali Mirzaghorbanali
Resource Operators Conference
Underground support system using tendons has been one of the significant achievements in Civil and Mining engineering endeavours in facing challenges of ground control. However, shear failure of rock bolts is still one of the least monitored phenonmenon in underground excavations with respect to seismic events. The understanding of the performance of rock bolts under dynamic loading condition requires a great deal of research. A series of tests were undertaken utilising a drop hammer mass of 600 Kg from a maximum height of 3.7 m over concrete blocks in the double shear box with chemical resin encapsulated a rock bolt …
Development Of Support Systems For Longwall Mining In The Bowen Basin, Central Queensland, George Klenowski, Phil Mcnamara
Development Of Support Systems For Longwall Mining In The Bowen Basin, Central Queensland, George Klenowski, Phil Mcnamara
Resource Operators Conference
The first longwall mine in Queensland was Central Colliery, located at the German Creek Mines. Production commenced in 1985 and shortly afterwards it broke the world record for longwall coal production. At that time longwall mining was generally not considered viable in Queensland due to technical problems associated with weak coal and excessive gas and water. Engineering solutions were developed and included properly designed chain pillars, in-seam methane drainage and efficient, dewatering pumping systems (Klenowski 2000; Klenowski and Winter, 2017). Following success at Central Colliery longwall mining commenced at the Oaky No.1 Underground Mine and Southern Colliery. This was followed …
Drill Rig Characteristics And Drilling Techniques Required For Maximum Borehole Depth With Directional Drilling, Frank Hungerford
Drill Rig Characteristics And Drilling Techniques Required For Maximum Borehole Depth With Directional Drilling, Frank Hungerford
Resource Operators Conference
Directional drilling has been the established form of in-seam drilling for gas drainage, exploration and water management for the past three decades. Although there has been a desire to achieve longer boreholes to depths similar to that achieved with surface drilling, seam conditions, equipment capacity and drilling methods have limited in-seam drilling depths. Development into a new area of Metropolitan Colliery required boreholes to depths of 2000 m to provide the required gas drainage. This offered an opportunity to use a combination of slide and rotary drilling similar to that used with Surface to Inseam (SIS) drilling to achieve the …
Dynamic Events At Longwall Face, Csm Mine, Czech Republic, Petr Waclawik, Jan Nemcik, Rudovan Kukutsch, Libin Gong, Gaetano Venticinque
Dynamic Events At Longwall Face, Csm Mine, Czech Republic, Petr Waclawik, Jan Nemcik, Rudovan Kukutsch, Libin Gong, Gaetano Venticinque
Resource Operators Conference
Presented here are the details of the seismic events that occurred at longwall 11 located at the CSM mine in the Ostrava coal region, Czech Republic. This longwall was excavated in a very complex area located within the shaft protective pillar and adjacent to the 50 m wide and steeply inclined fault zone at a depth of 850 m. In addition, 10 longwalls were extracted below each other over many years in several sloping seams located on the other side of the large sloping fault zone resulting in complex stress fields and large subsidence. The immediate roof above longwall 11 …
The Influence Of Intra-Seam Coal Character Variation On Outburst Risk Potential, Patrick Booth, Jan Nemcik, Ting Ren
The Influence Of Intra-Seam Coal Character Variation On Outburst Risk Potential, Patrick Booth, Jan Nemcik, Ting Ren
Resource Operators Conference
Effective quantification and management of risk associated with sudden gas release during mining (outburst) is reliant on coal and gas properties measurement bases being representative of the local geological and operational conditions. Contemporary gas emission calculation techniques often inappropriately generalise, or neglect, known site-specific extraction geometry, geological conditions, or heterogeneity and anisotropy within the working seam. Over 5000 coal core gas sample results, obtained from two Southern Sydney Basin Bulli Seam underground coal mines, plus coal samples collected from multiple locations at one studied mine, have been analysed in various geospatial and mining process-based context. Analysis has focused on the …
Dynamic Analysis Of Fault Slips And Their Influence On Coal Mine Rib Stability, Jan Nemcik, Gaetano Venticinque, Libin Gong
Dynamic Analysis Of Fault Slips And Their Influence On Coal Mine Rib Stability, Jan Nemcik, Gaetano Venticinque, Libin Gong
Resource Operators Conference
Historical data indicate that in deep coal mines the presence of faults in close proximity to excavations affect the frequency of coal bursts. A number of researchers have attempted to correlate the fault geometries to the frequency and severity of coal bursts but dynamic numerical modelling has not been used to show how faults can affect coal ejection from the rib side. The dynamic numerical analysis presented here show how different orientations of fault slips may affect coal bursts. To prove the concept, 89 cases of slipping fault geometries were modelled using the FLAC3D software and their effect on rib …
Oxygen Deficiency In Graham's Ratio Evaluation, Snezana Bajic, Sean Muller, Mladen Gido
Oxygen Deficiency In Graham's Ratio Evaluation, Snezana Bajic, Sean Muller, Mladen Gido
Resource Operators Conference
There are a number of indicators used to determine the level of coal oxidation in underground coal mines. The common indicator Graham’s ratio is the amount of carbon monoxide produced in proportion to the amount of oxygen consumed by the coal. The more carbon monoxide produced relative to the oxygen consumed (oxygen deficiency), the greater the intensity of the coal’s reaction. Graham’s ratio is often used as a trigger for Trigger Action Response Plans (TARPs) for the management of spontaneous combustion. This emphasises the importance of accurate measurement of oxygen deficiency and ability to successfully determine the status of underground …
Recent Case Studies Using The Remote Rocsil® Foam Plug System, Neil Alston, Jean-Luc Schmitter, Andrew Alcott, Russell Fry
Recent Case Studies Using The Remote Rocsil® Foam Plug System, Neil Alston, Jean-Luc Schmitter, Andrew Alcott, Russell Fry
Resource Operators Conference
ROCSIL® FOAM is a versatile product that has been successfully used to rapidly seal mines or critical areas of the mine directly in-seam or remotely via boreholes or shafts. The product is chemically stable, fire resistant, fast setting, has high expansion and excellent self-supporting characteristics making it an ideal product for these types of applications. It can also be used on sloping ground and with mine services such as conveyor structure or pipes remaining in-situ to form effective plug seals. For remote sealing, special mixing heads are designed to effectively deliver the product into mine roadways or shafts without the …