1. For diamond core drilling rocks with drillability levels 1-6 and completely homogeneous rock formations, it is generally appropriate to use natural surface-mounted drill bits, composite chip drill bits, polycrystalline drill bits, and partially sintered drill bits.
2. For hard dense rock formations (grade 7-12), it is generally advisable to use impregnated diamond, concentric or staggered tip ring groove drill bits, or fine-grained surface diamond core drill bits.
3. For coal-bearing formations such as fractures, soft-hard interlayers, crack development, or abrasive rock formations, it is appropriate to use reinforced galvanized dip-coated drill bits with good wear resistance.
4. The principle of selecting tire wear resistance according to the grinding performance, weathering degree and crushing degree of the rock is:
For abrasive rock formations, use a wear-resistant matrix.
For moderately abrasive rocks, a medium wear-resistant carcass should be selected. For rock formations with poor wear properties, a wear-resistant matrix should be used.
Due to the complexity, abrasiveness and hardness of the rock, a diamond core drill bit with a finer diamond grade and particle size should be selected.
Good grinding performance and large rock crushing degree. Under the condition of ensuring good diamond crust, choose a diamond core drill bit with high diamond content. In contrast, diamond coring bits use rock formations where diamond is less dense and has poor grinding properties.
For soft rock (level 1-4) and multiple rows of powder, composite drill bits or polycrystalline drill bits can be used. Bottom jet drilling should be used when coring rock formations susceptible to erosion. The abrasiveness classification of rock masses is shown in the table.