Tim Joseph - Profile on Academia.edu (original) (raw)
Papers by Tim Joseph
Data from 1/20 by volume small scale field trials for conventional and concept dipper designs is ... more Data from 1/20 by volume small scale field trials for conventional and concept dipper designs is evaluated and compared with 1⁄2 by volume mid sized and full sized ultra class conventional dipper designs. Digging effort through hoist motor current draw or strain gauging data was used as the performance indicator for comparison. Crowd effort, although available was not used as it represents a minor proportion of the total effort expended. The results of the comparison showed that there are linear relationships between dipper capacity and suspended load and peak hoist load. These relationships were used to establish normalizing factors in the units of original data measurement, allowing a common plot of all shovel sizes for the conventional dipper design. Given all evaluations are common, the conventional and concept dipper small scale field trial performance data suspended and peak load reference relationships were evaluated to allow prediction of the ultra class concept design perfo...
Proceedings of the 30th International Symposium on Automation and Robotics in Construction and Mining (ISARC 2013): Building the Future in Automation and Robotics, 2013
This paper considers the ideal truck-excavator combination, defined as the combination resulting ... more This paper considers the ideal truck-excavator combination, defined as the combination resulting in the lowest direct unit cost, in consideration of multiple haul scenarios characterized by different haul distances, material and equipment availability. Through the application of Monte Carlo simulation, selected for its unique ability to handle the uncertainty of activity durations, the "four to six passes" loading rule is shown to not correlate with the selection of the minimum cost fleet. Additionally, through the results of the simulation it is determined that the haul truck capacity has a greater effect on the overall efficiency of the system than does the excavator capacity. As a result, in order to arrive at efficient operations, the entire earthmoving system must be viewed as whole, namely, considering haulers together with excavators, as opposed to the popular method of first selecting a loading unit and then selecting a hauler obeying the "four to six passes" loading rule. Furthermore, truck utilization and excavator utilization exhibit an inverse relationship and neither directly correlates with the overall efficiency of the earthmoving operation. The following conclusions are drawn: first, with limited financial resources, it is more valuable to increase hauling unit size before increasing loading unit size and second, predefined rules or generalizations, not based on evidence, potentially eliminate optimal truck excavator combinations from being considered.
Modelling hauler movement in a distributed simulation of earthmoving operations
International Journal of Service and Computing Oriented Manufacturing, 2016
As critical components of mining and construction projects, earthmoving operations utilise heavy ... more As critical components of mining and construction projects, earthmoving operations utilise heavy equipment to execute excavation, loading, hauling, dumping, grading, and compacting tasks in a repetitive and almost continuous manner. Previous models tend to simulate these operations at a higher level, which ignores various independent factors such as road layout, road material, road maintenance frequency, trucks and excavator characteristics, and weather conditions, which will affect the efficiency, environment and the capital cost continuously and dynamically. To incorporate various independent factors and models into the simulation platform, the simulation presented herein is developed with a distributed approach using high level architecture (HLA) standards to enable inclusion of different comprehensive models and behaviours that affect these operations. This paper presents the design and development of a comprehensive simulation of earthmoving operations and the components of the simulation and models implemented in each, with a major focus on the transportation and hauling component. It also describes the distributed development process and showcases the implementation outcomes and sample use and validation of the simulation.
Earthmoving operations are critical components of many mining and construction projects. These op... more Earthmoving operations are critical components of many mining and construction projects. These operations utilize heavy equipment to execute excavation, loading, hauling, dumping, grading, and compacting tasks in a repetitive and almost continuous manner. The efficiency, environmental impact and cost of these operations are affected by many interdependent factors. These include road layout, road material, road maintenance frequency, trucks and excavator characteristics, and weather conditions. This paper describes the design and development of a comprehensive simulation of earthmoving operations. The simulation presented herein is developed with a distributed approach using High Level Architecture (HLA) Standards to enable inclusion of different models and behaviors that affect these operations. The paper presents the components of the simulation and models implemented in each, with more focus on the transportation and hauling component. It also describes the distributed development...
Journal of Civil & Environmental Engineering, 2013
Geotechnical and Geological Engineering, 2010
The strain softening of oil sand in the underfoot of ultra class mobile mining equipment, due to ... more The strain softening of oil sand in the underfoot of ultra class mobile mining equipment, due to the loading action of large mobile mining equipment such as trucks and shovels, yields a highly unstable condition for the operation of this ultra-class equipment. Soft ground conditions in oil sand, due to the low stiffness of the material a condition especially present in the summer, can cause high rack, pitch, and roll in trucks, leading to fatigue failure in structural components. For shovels, poor ground stability can cause twists in car bodies and undercarriages, resulting in major damages. Track and shovel frame failures due to this instability result in high maintenance costs. The authors carried out a geophysical study of the oil sand in order to evaluate the ground conditions under large mobile mining equipment. A geophysical investigation performed in summer 2001 encountered 6-8 m of thick soft material, commensurate with very low velocities, caused by the loosening of the surface material by heavy mining machinery and excavation; and a transition zone of up to 25-26 m depth approaching the in situ oil sand below. The depth of the oil sand zones can be calculated by using the refraction analysis technique. Spectral Analysis of Surface Waves was used to estimate the ground stiffness. A new technique is proposed to evaluate the changing ground stiffness during the use of ultra-class mobile mining equipment.
Geotechnical and Geological Engineering, 2010
Strain softening of oil sand under dynamic loading from large mining equipment inhibits the abili... more Strain softening of oil sand under dynamic loading from large mining equipment inhibits the ability of the equipment to function at optimal design performance. This paper looks at the findings of dynamic plate load tests, which effectively mimick the loading and unloading action of a shovel track pad. A pseudo-elastic model was proposed based on the results of the dynamic plate load testing to predict the deformation of oil sand under cyclic loading. Both field and laboratory cyclic plate load tests were performed on oil sand materials. The field tests were performed with different plate sizes, or footprints. The load was normalized based on the pressure stiffness concept in units of pressure per unit deformation. FLAC was used to model the field plate load test deformation with the elastic concept. The laboratory tests were performed at room temperature with more control on the load, loading rate, and cycles than possible during the field testing. Tests were conducted using a circular plate of 14.9 cm diameter, at stress magnitudes of 200, 400, 500 and 600 kPa. The plate load tests were conducted for varying loads, holding, and relaxation times of 0, 2, 5 and 10 min respectively for each magnitude of stress. The outcome of laboratory plate load tests show that after frequent cycles, the pressure stiffness (ratio of stress to deformation) converges on a plateau value of 8 kPa/ mm. The proposed approach can be used to evaluate oil sands ground performance, enhancing the prediction process for ground deformation under the operation of ultra-class mining equipment.
Data from 1/20 by volume small scale field trials for conventional and concept dipper designs is ... more Data from 1/20 by volume small scale field trials for conventional and concept dipper designs is evaluated and compared with 1⁄2 by volume mid sized and full sized ultra class conventional dipper designs. Digging effort through hoist motor current draw or strain gauging data was used as the performance indicator for comparison. Crowd effort, although available was not used as it represents a minor proportion of the total effort expended. The results of the comparison showed that there are linear relationships between dipper capacity and suspended load and peak hoist load. These relationships were used to establish normalizing factors in the units of original data measurement, allowing a common plot of all shovel sizes for the conventional dipper design. Given all evaluations are common, the conventional and concept dipper small scale field trial performance data suspended and peak load reference relationships were evaluated to allow prediction of the ultra class concept design perfo...
Proceedings of the 30th International Symposium on Automation and Robotics in Construction and Mining (ISARC 2013): Building the Future in Automation and Robotics, 2013
This paper considers the ideal truck-excavator combination, defined as the combination resulting ... more This paper considers the ideal truck-excavator combination, defined as the combination resulting in the lowest direct unit cost, in consideration of multiple haul scenarios characterized by different haul distances, material and equipment availability. Through the application of Monte Carlo simulation, selected for its unique ability to handle the uncertainty of activity durations, the "four to six passes" loading rule is shown to not correlate with the selection of the minimum cost fleet. Additionally, through the results of the simulation it is determined that the haul truck capacity has a greater effect on the overall efficiency of the system than does the excavator capacity. As a result, in order to arrive at efficient operations, the entire earthmoving system must be viewed as whole, namely, considering haulers together with excavators, as opposed to the popular method of first selecting a loading unit and then selecting a hauler obeying the "four to six passes" loading rule. Furthermore, truck utilization and excavator utilization exhibit an inverse relationship and neither directly correlates with the overall efficiency of the earthmoving operation. The following conclusions are drawn: first, with limited financial resources, it is more valuable to increase hauling unit size before increasing loading unit size and second, predefined rules or generalizations, not based on evidence, potentially eliminate optimal truck excavator combinations from being considered.
Modelling hauler movement in a distributed simulation of earthmoving operations
International Journal of Service and Computing Oriented Manufacturing, 2016
As critical components of mining and construction projects, earthmoving operations utilise heavy ... more As critical components of mining and construction projects, earthmoving operations utilise heavy equipment to execute excavation, loading, hauling, dumping, grading, and compacting tasks in a repetitive and almost continuous manner. Previous models tend to simulate these operations at a higher level, which ignores various independent factors such as road layout, road material, road maintenance frequency, trucks and excavator characteristics, and weather conditions, which will affect the efficiency, environment and the capital cost continuously and dynamically. To incorporate various independent factors and models into the simulation platform, the simulation presented herein is developed with a distributed approach using high level architecture (HLA) standards to enable inclusion of different comprehensive models and behaviours that affect these operations. This paper presents the design and development of a comprehensive simulation of earthmoving operations and the components of the simulation and models implemented in each, with a major focus on the transportation and hauling component. It also describes the distributed development process and showcases the implementation outcomes and sample use and validation of the simulation.
Earthmoving operations are critical components of many mining and construction projects. These op... more Earthmoving operations are critical components of many mining and construction projects. These operations utilize heavy equipment to execute excavation, loading, hauling, dumping, grading, and compacting tasks in a repetitive and almost continuous manner. The efficiency, environmental impact and cost of these operations are affected by many interdependent factors. These include road layout, road material, road maintenance frequency, trucks and excavator characteristics, and weather conditions. This paper describes the design and development of a comprehensive simulation of earthmoving operations. The simulation presented herein is developed with a distributed approach using High Level Architecture (HLA) Standards to enable inclusion of different models and behaviors that affect these operations. The paper presents the components of the simulation and models implemented in each, with more focus on the transportation and hauling component. It also describes the distributed development...
Journal of Civil & Environmental Engineering, 2013
Geotechnical and Geological Engineering, 2010
The strain softening of oil sand in the underfoot of ultra class mobile mining equipment, due to ... more The strain softening of oil sand in the underfoot of ultra class mobile mining equipment, due to the loading action of large mobile mining equipment such as trucks and shovels, yields a highly unstable condition for the operation of this ultra-class equipment. Soft ground conditions in oil sand, due to the low stiffness of the material a condition especially present in the summer, can cause high rack, pitch, and roll in trucks, leading to fatigue failure in structural components. For shovels, poor ground stability can cause twists in car bodies and undercarriages, resulting in major damages. Track and shovel frame failures due to this instability result in high maintenance costs. The authors carried out a geophysical study of the oil sand in order to evaluate the ground conditions under large mobile mining equipment. A geophysical investigation performed in summer 2001 encountered 6-8 m of thick soft material, commensurate with very low velocities, caused by the loosening of the surface material by heavy mining machinery and excavation; and a transition zone of up to 25-26 m depth approaching the in situ oil sand below. The depth of the oil sand zones can be calculated by using the refraction analysis technique. Spectral Analysis of Surface Waves was used to estimate the ground stiffness. A new technique is proposed to evaluate the changing ground stiffness during the use of ultra-class mobile mining equipment.
Geotechnical and Geological Engineering, 2010
Strain softening of oil sand under dynamic loading from large mining equipment inhibits the abili... more Strain softening of oil sand under dynamic loading from large mining equipment inhibits the ability of the equipment to function at optimal design performance. This paper looks at the findings of dynamic plate load tests, which effectively mimick the loading and unloading action of a shovel track pad. A pseudo-elastic model was proposed based on the results of the dynamic plate load testing to predict the deformation of oil sand under cyclic loading. Both field and laboratory cyclic plate load tests were performed on oil sand materials. The field tests were performed with different plate sizes, or footprints. The load was normalized based on the pressure stiffness concept in units of pressure per unit deformation. FLAC was used to model the field plate load test deformation with the elastic concept. The laboratory tests were performed at room temperature with more control on the load, loading rate, and cycles than possible during the field testing. Tests were conducted using a circular plate of 14.9 cm diameter, at stress magnitudes of 200, 400, 500 and 600 kPa. The plate load tests were conducted for varying loads, holding, and relaxation times of 0, 2, 5 and 10 min respectively for each magnitude of stress. The outcome of laboratory plate load tests show that after frequent cycles, the pressure stiffness (ratio of stress to deformation) converges on a plateau value of 8 kPa/ mm. The proposed approach can be used to evaluate oil sands ground performance, enhancing the prediction process for ground deformation under the operation of ultra-class mining equipment.