... drilling. They possess high penetration than conventional diamond core bit from soft to medium-hard formations, ... 96, 113, 123, 133 and 153mm outer diameters. PDC core bit : BQ, NQ, NQ3, HQ, HQ3, PQ, ... hydrapower station grouting project ( wireline core drilling and double-tube core drilling)1.Drill rod:BQ,NQ,HQ,PQ, ... BT, NT, HT2.Core barrel: BQ NQ ...