1 When underground mining is converted to open-pit mining, the location of all underground roadways, goafs and pillars shall be plotted on the mine level and section comparison map. The treatment methods for underground roadways and goafs should be determined in the design, and the treatment methods for large goafs should be studied in detail. Important mine projects should not be placed within the mobile range of underground mining.
2 When the mine has been reclaimed by the filling method and the open mining is used to return to the mining column, the appropriate perforation, blasting and shoveling processes should be determined and necessary safety precautions should be taken.
3 During the transition period from underground to open air, the impact of open-pit mining on the prevention and drainage of underground mining should be analyzed.
2 When the mine has been reclaimed by the filling method and the open mining is used to return to the mining column, the appropriate perforation, blasting and shoveling processes should be determined and necessary safety precautions should be taken.
3 During the transition period from underground to open air, the impact of open-pit mining on the prevention and drainage of underground mining should be analyzed.
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