An underground iron mine in China has been used as a case-study to research the subsidence due to ore extraction and backfilling during open stoping operations. A 3-D discontinuum numerical model was built incorporati...An underground iron mine in China has been used as a case-study to research the subsidence due to ore extraction and backfilling during open stoping operations. A 3-D discontinuum numerical model was built incorporating geologic complexities including faults and interfaces between different lithologies,and the stoping and backfilling sequence adopted from the mine plans. The stoping was carried out in two vertically stacked horizontal layers, with a total of 16 stopes. Large displacements of up to 50 cm were observed along the roof of the stopes, and a maximum surface subsidence of 22.5 cm was observed.Backfilling was found to eliminate subsequent displacements and subsidence. The extraction of the upper orebody was found to influence displacements in the lower orebody. Finally, a subsidence profile was constructed to show the subsidence at all locations along the length of the surface and region of influence on the surface.展开更多
Caving in coal mines releases significant amounts of dust and gas. This is exhausted from the mine by forcing the air to travel through the caved zones into a set of roadways known as bleeders. These bleeder entries a...Caving in coal mines releases significant amounts of dust and gas. This is exhausted from the mine by forcing the air to travel through the caved zones into a set of roadways known as bleeders. These bleeder entries are operated for the life of the mine, and therefore, they have to be kept in stable condition. Caving operations in coal mines are associated with Iongwall mines and complete pillar extraction. The pillars adjoining the caved zone sometimes show rib failures, posing a hazard for mine personnel travelling through the entry. In this paper, we present the results from analyses of bleeder pillars that are near the caved zones and are susceptible to damage because of the transfer of load during the caving process. In this study, bleeder pillars were simulated in a displacement discontinuity program. Results showed that the vertical stresses on bleeder pillars increased while the safety factor of bleeder pillar decreased during the caving process; however, when the caved zone completely consolidated, both the stresses and safety factor did not change for the remaining extraction. When similar extraction was performed at deeoer denths, vertical stress on pillars increased significantly_展开更多
基金the support from the National Natural Science Foundation of China (No. 51404024)partially funded by the NIOSH of the Centers for Disease Control and Prevention, USA through Contract No.200-201139886 given to the second author
文摘An underground iron mine in China has been used as a case-study to research the subsidence due to ore extraction and backfilling during open stoping operations. A 3-D discontinuum numerical model was built incorporating geologic complexities including faults and interfaces between different lithologies,and the stoping and backfilling sequence adopted from the mine plans. The stoping was carried out in two vertically stacked horizontal layers, with a total of 16 stopes. Large displacements of up to 50 cm were observed along the roof of the stopes, and a maximum surface subsidence of 22.5 cm was observed.Backfilling was found to eliminate subsequent displacements and subsidence. The extraction of the upper orebody was found to influence displacements in the lower orebody. Finally, a subsidence profile was constructed to show the subsidence at all locations along the length of the surface and region of influence on the surface.
基金CERB (Coal and Energy Research Bureau) for supporting this research work
文摘Caving in coal mines releases significant amounts of dust and gas. This is exhausted from the mine by forcing the air to travel through the caved zones into a set of roadways known as bleeders. These bleeder entries are operated for the life of the mine, and therefore, they have to be kept in stable condition. Caving operations in coal mines are associated with Iongwall mines and complete pillar extraction. The pillars adjoining the caved zone sometimes show rib failures, posing a hazard for mine personnel travelling through the entry. In this paper, we present the results from analyses of bleeder pillars that are near the caved zones and are susceptible to damage because of the transfer of load during the caving process. In this study, bleeder pillars were simulated in a displacement discontinuity program. Results showed that the vertical stresses on bleeder pillars increased while the safety factor of bleeder pillar decreased during the caving process; however, when the caved zone completely consolidated, both the stresses and safety factor did not change for the remaining extraction. When similar extraction was performed at deeoer denths, vertical stress on pillars increased significantly_
