Drilling/blasting broken ground
Drilling/blasting broken ground
(OP)
Has anyone had experience in open-pit production drilling/blasting of previously broken ground?
We are working down to expose old, pillar-extracted coal seam workings. The sandstone overburden for about 15metres above the seam is severely fractured due to highly variable subsidence, and has significant voids. Our objective is to fill any major open voids to enable trucks & excavator to work on benches above. However we are having trouble drilling blastholes (100mm holes) due to lack of air return clogging holes with cuttings, and also broken ground jamming drill and holes collapsing. We can probably use bottom plugs/stemming & liners to contain the explosive - it is mainly a drilling rather than blasting problem.
Any advice would be appreciated.
We are working down to expose old, pillar-extracted coal seam workings. The sandstone overburden for about 15metres above the seam is severely fractured due to highly variable subsidence, and has significant voids. Our objective is to fill any major open voids to enable trucks & excavator to work on benches above. However we are having trouble drilling blastholes (100mm holes) due to lack of air return clogging holes with cuttings, and also broken ground jamming drill and holes collapsing. We can probably use bottom plugs/stemming & liners to contain the explosive - it is mainly a drilling rather than blasting problem.
Any advice would be appreciated.





RE: Drilling/blasting broken ground
RDS CBC Engineering
RE: Drilling/blasting broken ground
Thanks for your interest. We have been able to get good coal recovery from the pillars once we get there, but the big problem remains that the overburden drill loses too much air into the broken/caved ground above the old workings which in turn leads to jamming rods in holes etc.