Ernest Baafid - Academia.edu (original) (raw)

Papers by Ernest Baafid

Proceedings of the 27th International Symposium on Mine Planning and Equipment Selection - MPES 2018, 2019

Computer-based truck dispatching systems are widely used to improve equipment utilisation and pro... more Computer-based truck dispatching systems are widely used to improve equipment utilisation and productivity in open-pit mines. Such systems should be based on models that reflect the realistic operation of a truck-shovel system and utilise a suitable simulation tool. In this paper, a discrete-event truck-shovel simulation model, referred to as Truck and Shovel JaamSim Simulator (TSJSim), was developed. The TSJSim simulation model may be used to evaluate the Key Performance Indicators (KPIs) of the truck-shovel mining system in an open-pit mine. TSJSim considers a truck as an individual traffic vehicle unit that dynamically interacts with other trucks in the system as well as other elements of the traffic network. The developed model provides the capability for evaluating the impacts of bunching, intersection traffic management and truck-allocation strategies on a surface mine truck-shovel system. The model can also be used to estimate the optimal truck fleet size for the entire truck...

Environmental Geology, 2006

Longwall mining accounts for more than 75% of underground coal production in Australia. It is a p... more Longwall mining accounts for more than 75% of underground coal production in Australia. It is a popular underground coal mining method worldwide, mainly due to its high extraction ratio, high productivity and increased safety due to improved powered support units. A longwall system requires significant capital investment, and it is necessary to minimise the financial risk associated with this investment. Minimisation of this financial risk requires a sound knowledge of the relationship between underlying operational/technical constraints and associated costs. A discrete simulation model using the Flexsim 3D virtual reality environment has been developed to assist management evaluate the impact of technical and operational constraints on longwall productivity. Using such a model, any set of operational scenarios can be evaluated to establish the optimum operational parameters for a longwall system.

Proceedings of the 1998 Coal Operators\u27 Conference. All papers in these proceedings are peer r... more Proceedings of the 1998 Coal Operators\u27 Conference. All papers in these proceedings are peer reviewed. ISBN: 0 86418 477 8

Fully encapsulated roof bolts have been proven to confine the roof and rib strata actively, while... more Fully encapsulated roof bolts have been proven to confine the roof and rib strata actively, while steel mesh only provides passive support and protection from falling rocks as they dislodge from the roof. To provide better stability of the mine roadway skin, replacement of the steel mesh with a spray on polymer liner is being investigated. Among the many benefits that may be realised by the application of quick setting spray on polymer liners as skin support are an increase in development rates and improved safety for working personnel. Extensive testing of a range of available polymer formulations is currently being undertaken; this particular study is to determine how Thin Spray on Liners (TSL) behave in conditions encountered in underground coal mines and demonstrates their superior properties over steel mesh as an alternative form of roof skin support

Consider the ensemble of Real Symmetric Toeplitz Matrices, each entry iidrv from a fixed probabil... more Consider the ensemble of Real Symmetric Toeplitz Matrices, each entry iidrv from a fixed probability distribution p of mean 0, variance 1, and finite higher moments. The limiting spectral measure (the density of normalized eigenvalues) converges weakly to a new universal distribution with unbounded support, independent of p. This distribution's moments are almost those of the Gaussian's; the deficit may be interpreted in terms of Diophantine obstructions. With a little more work, we obtain almost sure convergence. An investigation of spacings between adjacent normalized eigenvalues looks Poissonian, and not GOE.

Designing an appropriate dewatering system at the early stages of mine planning is important in m... more Designing an appropriate dewatering system at the early stages of mine planning is important in managing and controlling groundwater inflow into big open pit mines. To better design a dewatering system, it is necessary to investigate the hydrodynamic parameters of the aquifer involved with the mining operation. Such investigations are also important for the prediction of post-mining pit lake formation and mine drainage quality control. A series of pumping tests was carried out at Sangan iron mine, Mashhad, Iran, in order to determine the transmissivity and storativity of the confined aquifer. The pumping data were first evaluated with analytical Theis and Cooper-Jacob equations. An axi-symmetric finite element software, SEEP/W, was used to simulate transient, radial flow to a fully penetrating well in the confined aquifer. The groundwater recovery pattern was also considered in the numerical model. Analytical solutions and field data were used for the evaluation of the numerical mod...

Prediction of groundwater inflow and subsequence design of pumping system is an important problem... more Prediction of groundwater inflow and subsequence design of pumping system is an important problem in surface mine development. The mining operation will be carried out without any major problem if the pumping system is appropriately designed. The hydrogeological studies are necessary at the early stages of mine development. The main objective of this research was to predict hydraulic head changes versus time and distance in a confined aquifer at Sangan iron mine which is located at 280 km from southeast of Mashhad, Iran. A numerical finite element model using SEEP/W computer software was presented. A Theis analytical solution and field data (well. No. D4W3) were used to verify model prediction. The results show a close agreement between model predictions and those data obtained from the field and the analytical Theis solution.

Journal of Hydrology, 2016

In this study, a hybrid intelligent model was designed to predict groundwater inflow to a mine pi... more In this study, a hybrid intelligent model was designed to predict groundwater inflow to a mine pit during its advance. The novel hybrid method coupling artificial neural network (ANN) with genetic algorithm (GA) called ANN-GA, was utilised. Ratios of pit depth to aquifer thickness, pit bottom radius to its top radius, inverse of pit advance time and the hydraulic head (HH) in the observation wells to the distance of observation wells from the centre of pit were used as inputs to the network. An ANN-GA with 4-5-3-1 arrangement was found capable of predicting the groundwater inflow to mine pit. The accuracy and reliability of the model was verified by field data. The predicted results were very close to the field data. The correlation coefficient (R) value was 0.998 for the training set, and in testing stage it was 0.99.

Due to the high levels of uncertainty in underground coal mining operations, delays occur regular... more Due to the high levels of uncertainty in underground coal mining operations, delays occur regularly which inadvertently reduce the utilisation of mining equipment. In most coal mines delay data is primarily sourced from shift reports, machine monitoring and production systems. The recording process is initiated commonly at the end of a shift to ensure the correct information is recorded for the managerial decision process. An issue that the Australian coal industry faces is the lack of a standardised delay recording process and delay classification system. Tools used within the industry to analyse delay data are mostly mine specific and offer no means of comparing the mine performance to the performance at other mine sites. This paper describes a VBA based delay data analysis tool UCDelay for underground coal mines. UCDelay is an add-in Excel module for classification of delay data into a standardised form.

Context: Discussion modules are generally limited to student-to-student peer learning, with guide... more Context: Discussion modules are generally limited to student-to-student peer learning, with guided moderation by tutors and lecturers. This paper aims to establish that there can be valuable additional learning by using a similar approach, but involving industry professionals to provide mentoring and responses to students' questions in specific subject and/or topical areas. A real advantage of this approach is the translation of theory and technical knowledge into real world problems. The industry-based forum used in this trial resulted in students re-calibrating what they are being taught and what awaits them in the real world and was also invaluable to lecturers as it alerted them to the relevance of what is being taught during lectures/tutorials. Mining engineering was chosen as the focus for this study for two reasons. One was the background of the authors and the subjects they teach. The other is that, unlike most other engineering disciplines, mining engineering profession...

Abstract: The development of the Australian Coal Associ ation Research Program (ACARP) funded “on... more Abstract: The development of the Australian Coal Associ ation Research Program (ACARP) funded “one stop shop” information management system for the coal mining industry is described. The site www.undergroundcoal.com.au went live on 28 August 2009 with various sub-modules including an introduction to underground coal mining practices and a handbook of roadway development practice. The site also includes presentations from ACARP six-monthly workshops on current roadway development practice. These workshops provide an invaluable opportunity to share state of the art knowledge in roadway development practice, to learn of emerging Research and Development (Rand D) programs and development of equipment and technology by Original Equipment Manufacturers (OEMs). INTRODUCTION A review of current roadway development practice (Gibson, 2005) found that there was little information transfer across underground coal mines, even for mine s within the same company, and that mines were unaware of dev...

The University of Wollongong in collaboration with the Australian coal mining industry has shown ... more The University of Wollongong in collaboration with the Australian coal mining industry has shown that a viable polymer-based alternative to steel mesh in underground roadway support applications can be developed to eliminate the use and handling of steel mesh. The feasibility of developing polymeric alternatives to steel mesh in underground roadway support applications has been established, the physical and material constraints to be endured by any new polymeric skin reinforcement system have been identified by measuring the mechanical properties of steel mesh, and materials that can be spray-applied have been identified. The study has also shown that polymer mechanical properties can be optimised to produce similar mechanical properties (modulus, yield stress, elongation-at-break etc) to steel mesh. The identified materials will allow the face support cycle to be fully automated, or at least remotely operated and installed, enabling the removal of personnel from the immediate face ...

Each year, students enrolled in the subject Engineering Computing 1 at the University of Wollongo... more Each year, students enrolled in the subject Engineering Computing 1 at the University of Wollongong, Wollongong, Australia, are surveyed on the first day of classes in order to assess their prior knowledge of the subject content. The survey results show considerable diversity in students’ backgrounds. On average, about 10% are not familiar with the use of personal computers (PCs), 5% have never used e-mail/World Wide Web, 30% have not used spreadsheets and 60% have not programmed in a high level language. However, within these averages are some students with advanced skills and others with quite limited skills. Many of those students with a limited knowledge of computers come from developing countries, including Sudan, Indonesia and the Indian subcontinent. In the paper, the authors discuss how computer based training (CBT) packages are utilised to form the basis of a student centred self-learning system. These CBT resources allow the lecturers to better manage class-time by having ...

Ground subsidence due to mining is a common dilemma confronting the underground coal mining indus... more Ground subsidence due to mining is a common dilemma confronting the underground coal mining industry. The effects of underground longwall mining on river valleys have come under scrutiny, especially when mining is located underneath catchment areas. As public awareness of mining impacts on the environment increases, there is the need to develop damage mitigation strategies. Results of numerical modelling show that river valley response to underground longwall mining can be simulated and evaluated.

The underground coal mine pillar development cycle consists primarily of three sets of interdepen... more The underground coal mine pillar development cycle consists primarily of three sets of interdependent and synchronised cycles, i.e., the coal cutting cycle by a continuous miner (CM), the support cycle by a roof bolter and the coal transport cycle to the boot end by a shuttle car. Coal cutting by a CM is generally not seen as a constraint as, in almost all cases, the capacity of the CM far exceeds the demand placed on it. Therefore, in essence, the pillar development process can be either transport constrained or support constrained. Using a discrete simulation model, it was shown that for a case study mine a CM configured with two bolting rigs was support constrained when the distance from the boot end to the face was short. It was suspected that as the distance from the face to the boot end increased and development would change from being support constrained to transport constrained. For this case however, introduction of additional bolting rigs did not change the development rat...

Current advances in roof support automation require a fast and effective skin reinforcement of un... more Current advances in roof support automation require a fast and effective skin reinforcement of underground mine roadways. To satisfy these needs a strong and tough fibre reinforced polymeric alternative is emerging as a logical substitute to the old steel mesh support system. Differences between steel mesh and polymer skin behaviour are investigated. Computational models are utilised to compare these two skin support systems with a view to optimising the performance needed for effective roadway skin reinforcement. In particular, development of a strong and resistant shell that minimises movement along the fractured rock and coal surfaces found between the roof bolt anchors is recommended. A strong surface adhesion and the strength of a reinforced polymer skin can provide the necessary toughening mechanism required to enhance roadway surface support by forming a reinforced polymer/rock surface layer. The fractured rock mass in its undisturbed phase is relatively stiff while confineme...

Current research into strata support automation in coal mine roadways requires development of a s... more Current research into strata support automation in coal mine roadways requires development of a strong, tough and effective skin support that can be applied remotely. To investigate suitability of a glass fibre reinforced polymeric thin Spray-On Liner (TSL) numerous small and large scale samples were tested. These tests include; the tear load due to the lateral movement of TSL to fail in tear through the bolts installed in underground roadway roof, and the ‘truser tear’ due to the differential movement of the supported strata. The laboratory experiments suggested that a polymer based TSL can withstand substantial tear loads and despite the tear failure, the remaining TSL sheet can maintain strata support effectively. The tear strength tests were conducted using a standard 22 mm diameter steel bolt tearing the 5 mm thick polymer sheets reinforced with two or three glass fibre layers. The trouser tear tests were conducted with two and three layers of glass fibre reinforcement. The bol...

Thin spray-on liners (TSLs) have been attracting more and more attention as an alternative to the... more Thin spray-on liners (TSLs) have been attracting more and more attention as an alternative to the steel mesh in underground roadway support. In order to investigate and compare the compressive strength of glass fibre reinforced ToughSkin TSL developed at the University of Wollongong, a compression test was developed using the cube samples of 40 mm in size. The effect of a small amount of glass fibre in the polymer matrix was tested. The test results indicate that the compressive strength and the material stiffness of the cube samples increased with the increase of glass fibre. All of samples exhibited ductile stress strain curve as they had a yield point and a fracture point. The ductile ToughSkin yield characteristics are very important as sudden brittle failure is considered unsafe for mining practices.

Due to the high levels of uncertainty in underground coal mining operations, delays occur regular... more Due to the high levels of uncertainty in underground coal mining operations, delays occur regularly which inadvertently reduce the utilisation of mining equipment. In most coal mines delay data is primarily sourced from shift reports, machine monitoring and production systems. The recording process is initiated commonly at the end of a shift to ensure the correct information is recorded for the managerial decision process. An issue that the Australian coal industry faces is the lack of a standardised delay recording process and delay classification system. Tools used within the industry to analyse delay data are mostly mine specific and offer no means of comparing the mine performance to the performance at other mine sites. This paper describes a VBA based delay data analysis tool UCDelay for underground coal mines. UCDelay is an add-in Excel module for classification of delay data into a standardised form.

Proceedings of the 27th International Symposium on Mine Planning and Equipment Selection - MPES 2018, 2019

Computer-based truck dispatching systems are widely used to improve equipment utilisation and pro... more Computer-based truck dispatching systems are widely used to improve equipment utilisation and productivity in open-pit mines. Such systems should be based on models that reflect the realistic operation of a truck-shovel system and utilise a suitable simulation tool. In this paper, a discrete-event truck-shovel simulation model, referred to as Truck and Shovel JaamSim Simulator (TSJSim), was developed. The TSJSim simulation model may be used to evaluate the Key Performance Indicators (KPIs) of the truck-shovel mining system in an open-pit mine. TSJSim considers a truck as an individual traffic vehicle unit that dynamically interacts with other trucks in the system as well as other elements of the traffic network. The developed model provides the capability for evaluating the impacts of bunching, intersection traffic management and truck-allocation strategies on a surface mine truck-shovel system. The model can also be used to estimate the optimal truck fleet size for the entire truck...

Environmental Geology, 2006

Longwall mining accounts for more than 75% of underground coal production in Australia. It is a p... more Longwall mining accounts for more than 75% of underground coal production in Australia. It is a popular underground coal mining method worldwide, mainly due to its high extraction ratio, high productivity and increased safety due to improved powered support units. A longwall system requires significant capital investment, and it is necessary to minimise the financial risk associated with this investment. Minimisation of this financial risk requires a sound knowledge of the relationship between underlying operational/technical constraints and associated costs. A discrete simulation model using the Flexsim 3D virtual reality environment has been developed to assist management evaluate the impact of technical and operational constraints on longwall productivity. Using such a model, any set of operational scenarios can be evaluated to establish the optimum operational parameters for a longwall system.

Proceedings of the 1998 Coal Operators\u27 Conference. All papers in these proceedings are peer r... more Proceedings of the 1998 Coal Operators\u27 Conference. All papers in these proceedings are peer reviewed. ISBN: 0 86418 477 8

Fully encapsulated roof bolts have been proven to confine the roof and rib strata actively, while... more Fully encapsulated roof bolts have been proven to confine the roof and rib strata actively, while steel mesh only provides passive support and protection from falling rocks as they dislodge from the roof. To provide better stability of the mine roadway skin, replacement of the steel mesh with a spray on polymer liner is being investigated. Among the many benefits that may be realised by the application of quick setting spray on polymer liners as skin support are an increase in development rates and improved safety for working personnel. Extensive testing of a range of available polymer formulations is currently being undertaken; this particular study is to determine how Thin Spray on Liners (TSL) behave in conditions encountered in underground coal mines and demonstrates their superior properties over steel mesh as an alternative form of roof skin support

Consider the ensemble of Real Symmetric Toeplitz Matrices, each entry iidrv from a fixed probabil... more Consider the ensemble of Real Symmetric Toeplitz Matrices, each entry iidrv from a fixed probability distribution p of mean 0, variance 1, and finite higher moments. The limiting spectral measure (the density of normalized eigenvalues) converges weakly to a new universal distribution with unbounded support, independent of p. This distribution's moments are almost those of the Gaussian's; the deficit may be interpreted in terms of Diophantine obstructions. With a little more work, we obtain almost sure convergence. An investigation of spacings between adjacent normalized eigenvalues looks Poissonian, and not GOE.

Designing an appropriate dewatering system at the early stages of mine planning is important in m... more Designing an appropriate dewatering system at the early stages of mine planning is important in managing and controlling groundwater inflow into big open pit mines. To better design a dewatering system, it is necessary to investigate the hydrodynamic parameters of the aquifer involved with the mining operation. Such investigations are also important for the prediction of post-mining pit lake formation and mine drainage quality control. A series of pumping tests was carried out at Sangan iron mine, Mashhad, Iran, in order to determine the transmissivity and storativity of the confined aquifer. The pumping data were first evaluated with analytical Theis and Cooper-Jacob equations. An axi-symmetric finite element software, SEEP/W, was used to simulate transient, radial flow to a fully penetrating well in the confined aquifer. The groundwater recovery pattern was also considered in the numerical model. Analytical solutions and field data were used for the evaluation of the numerical mod...

Prediction of groundwater inflow and subsequence design of pumping system is an important problem... more Prediction of groundwater inflow and subsequence design of pumping system is an important problem in surface mine development. The mining operation will be carried out without any major problem if the pumping system is appropriately designed. The hydrogeological studies are necessary at the early stages of mine development. The main objective of this research was to predict hydraulic head changes versus time and distance in a confined aquifer at Sangan iron mine which is located at 280 km from southeast of Mashhad, Iran. A numerical finite element model using SEEP/W computer software was presented. A Theis analytical solution and field data (well. No. D4W3) were used to verify model prediction. The results show a close agreement between model predictions and those data obtained from the field and the analytical Theis solution.

Journal of Hydrology, 2016

In this study, a hybrid intelligent model was designed to predict groundwater inflow to a mine pi... more In this study, a hybrid intelligent model was designed to predict groundwater inflow to a mine pit during its advance. The novel hybrid method coupling artificial neural network (ANN) with genetic algorithm (GA) called ANN-GA, was utilised. Ratios of pit depth to aquifer thickness, pit bottom radius to its top radius, inverse of pit advance time and the hydraulic head (HH) in the observation wells to the distance of observation wells from the centre of pit were used as inputs to the network. An ANN-GA with 4-5-3-1 arrangement was found capable of predicting the groundwater inflow to mine pit. The accuracy and reliability of the model was verified by field data. The predicted results were very close to the field data. The correlation coefficient (R) value was 0.998 for the training set, and in testing stage it was 0.99.

Due to the high levels of uncertainty in underground coal mining operations, delays occur regular... more Due to the high levels of uncertainty in underground coal mining operations, delays occur regularly which inadvertently reduce the utilisation of mining equipment. In most coal mines delay data is primarily sourced from shift reports, machine monitoring and production systems. The recording process is initiated commonly at the end of a shift to ensure the correct information is recorded for the managerial decision process. An issue that the Australian coal industry faces is the lack of a standardised delay recording process and delay classification system. Tools used within the industry to analyse delay data are mostly mine specific and offer no means of comparing the mine performance to the performance at other mine sites. This paper describes a VBA based delay data analysis tool UCDelay for underground coal mines. UCDelay is an add-in Excel module for classification of delay data into a standardised form.

Context: Discussion modules are generally limited to student-to-student peer learning, with guide... more Context: Discussion modules are generally limited to student-to-student peer learning, with guided moderation by tutors and lecturers. This paper aims to establish that there can be valuable additional learning by using a similar approach, but involving industry professionals to provide mentoring and responses to students' questions in specific subject and/or topical areas. A real advantage of this approach is the translation of theory and technical knowledge into real world problems. The industry-based forum used in this trial resulted in students re-calibrating what they are being taught and what awaits them in the real world and was also invaluable to lecturers as it alerted them to the relevance of what is being taught during lectures/tutorials. Mining engineering was chosen as the focus for this study for two reasons. One was the background of the authors and the subjects they teach. The other is that, unlike most other engineering disciplines, mining engineering profession...

Abstract: The development of the Australian Coal Associ ation Research Program (ACARP) funded “on... more Abstract: The development of the Australian Coal Associ ation Research Program (ACARP) funded “one stop shop” information management system for the coal mining industry is described. The site www.undergroundcoal.com.au went live on 28 August 2009 with various sub-modules including an introduction to underground coal mining practices and a handbook of roadway development practice. The site also includes presentations from ACARP six-monthly workshops on current roadway development practice. These workshops provide an invaluable opportunity to share state of the art knowledge in roadway development practice, to learn of emerging Research and Development (Rand D) programs and development of equipment and technology by Original Equipment Manufacturers (OEMs). INTRODUCTION A review of current roadway development practice (Gibson, 2005) found that there was little information transfer across underground coal mines, even for mine s within the same company, and that mines were unaware of dev...

The University of Wollongong in collaboration with the Australian coal mining industry has shown ... more The University of Wollongong in collaboration with the Australian coal mining industry has shown that a viable polymer-based alternative to steel mesh in underground roadway support applications can be developed to eliminate the use and handling of steel mesh. The feasibility of developing polymeric alternatives to steel mesh in underground roadway support applications has been established, the physical and material constraints to be endured by any new polymeric skin reinforcement system have been identified by measuring the mechanical properties of steel mesh, and materials that can be spray-applied have been identified. The study has also shown that polymer mechanical properties can be optimised to produce similar mechanical properties (modulus, yield stress, elongation-at-break etc) to steel mesh. The identified materials will allow the face support cycle to be fully automated, or at least remotely operated and installed, enabling the removal of personnel from the immediate face ...

Each year, students enrolled in the subject Engineering Computing 1 at the University of Wollongo... more Each year, students enrolled in the subject Engineering Computing 1 at the University of Wollongong, Wollongong, Australia, are surveyed on the first day of classes in order to assess their prior knowledge of the subject content. The survey results show considerable diversity in students’ backgrounds. On average, about 10% are not familiar with the use of personal computers (PCs), 5% have never used e-mail/World Wide Web, 30% have not used spreadsheets and 60% have not programmed in a high level language. However, within these averages are some students with advanced skills and others with quite limited skills. Many of those students with a limited knowledge of computers come from developing countries, including Sudan, Indonesia and the Indian subcontinent. In the paper, the authors discuss how computer based training (CBT) packages are utilised to form the basis of a student centred self-learning system. These CBT resources allow the lecturers to better manage class-time by having ...

Ground subsidence due to mining is a common dilemma confronting the underground coal mining indus... more Ground subsidence due to mining is a common dilemma confronting the underground coal mining industry. The effects of underground longwall mining on river valleys have come under scrutiny, especially when mining is located underneath catchment areas. As public awareness of mining impacts on the environment increases, there is the need to develop damage mitigation strategies. Results of numerical modelling show that river valley response to underground longwall mining can be simulated and evaluated.

The underground coal mine pillar development cycle consists primarily of three sets of interdepen... more The underground coal mine pillar development cycle consists primarily of three sets of interdependent and synchronised cycles, i.e., the coal cutting cycle by a continuous miner (CM), the support cycle by a roof bolter and the coal transport cycle to the boot end by a shuttle car. Coal cutting by a CM is generally not seen as a constraint as, in almost all cases, the capacity of the CM far exceeds the demand placed on it. Therefore, in essence, the pillar development process can be either transport constrained or support constrained. Using a discrete simulation model, it was shown that for a case study mine a CM configured with two bolting rigs was support constrained when the distance from the boot end to the face was short. It was suspected that as the distance from the face to the boot end increased and development would change from being support constrained to transport constrained. For this case however, introduction of additional bolting rigs did not change the development rat...

Current advances in roof support automation require a fast and effective skin reinforcement of un... more Current advances in roof support automation require a fast and effective skin reinforcement of underground mine roadways. To satisfy these needs a strong and tough fibre reinforced polymeric alternative is emerging as a logical substitute to the old steel mesh support system. Differences between steel mesh and polymer skin behaviour are investigated. Computational models are utilised to compare these two skin support systems with a view to optimising the performance needed for effective roadway skin reinforcement. In particular, development of a strong and resistant shell that minimises movement along the fractured rock and coal surfaces found between the roof bolt anchors is recommended. A strong surface adhesion and the strength of a reinforced polymer skin can provide the necessary toughening mechanism required to enhance roadway surface support by forming a reinforced polymer/rock surface layer. The fractured rock mass in its undisturbed phase is relatively stiff while confineme...

Current research into strata support automation in coal mine roadways requires development of a s... more Current research into strata support automation in coal mine roadways requires development of a strong, tough and effective skin support that can be applied remotely. To investigate suitability of a glass fibre reinforced polymeric thin Spray-On Liner (TSL) numerous small and large scale samples were tested. These tests include; the tear load due to the lateral movement of TSL to fail in tear through the bolts installed in underground roadway roof, and the ‘truser tear’ due to the differential movement of the supported strata. The laboratory experiments suggested that a polymer based TSL can withstand substantial tear loads and despite the tear failure, the remaining TSL sheet can maintain strata support effectively. The tear strength tests were conducted using a standard 22 mm diameter steel bolt tearing the 5 mm thick polymer sheets reinforced with two or three glass fibre layers. The trouser tear tests were conducted with two and three layers of glass fibre reinforcement. The bol...

Thin spray-on liners (TSLs) have been attracting more and more attention as an alternative to the... more Thin spray-on liners (TSLs) have been attracting more and more attention as an alternative to the steel mesh in underground roadway support. In order to investigate and compare the compressive strength of glass fibre reinforced ToughSkin TSL developed at the University of Wollongong, a compression test was developed using the cube samples of 40 mm in size. The effect of a small amount of glass fibre in the polymer matrix was tested. The test results indicate that the compressive strength and the material stiffness of the cube samples increased with the increase of glass fibre. All of samples exhibited ductile stress strain curve as they had a yield point and a fracture point. The ductile ToughSkin yield characteristics are very important as sudden brittle failure is considered unsafe for mining practices.

Due to the high levels of uncertainty in underground coal mining operations, delays occur regular... more Due to the high levels of uncertainty in underground coal mining operations, delays occur regularly which inadvertently reduce the utilisation of mining equipment. In most coal mines delay data is primarily sourced from shift reports, machine monitoring and production systems. The recording process is initiated commonly at the end of a shift to ensure the correct information is recorded for the managerial decision process. An issue that the Australian coal industry faces is the lack of a standardised delay recording process and delay classification system. Tools used within the industry to analyse delay data are mostly mine specific and offer no means of comparing the mine performance to the performance at other mine sites. This paper describes a VBA based delay data analysis tool UCDelay for underground coal mines. UCDelay is an add-in Excel module for classification of delay data into a standardised form.