... by API&ISO9001:2008 New PDC Bits for water well drilling (12-1/4") we can supply rock bits,tricone bits, ... compact) grades and shapes applied for rock formations as follows:1. Andesite, marble, metamorphic schist (For hard, low abrasive ... ,637 TypeTricone bits, Steel tooth bits, PDC bits Applicable water well, oil field, construction, geothermal, directional boring, and underground foundation ...