Abstract: A method and system for drilling or cutting a subterranean well or formation 52 using a drilling rig 5, a drill string 55, a plurality of solid material impactors 100, a drilling fluid and a drill bit 60 is disclosed. This invention may have particular utility in drilling wells for the petroleum industry and for cutting formation in the mining and tunnel boring industries. In a preferred embodiment, a plurality of solid material impactors are introduced into the drilling fluid and pumped through the drill string and drill bit to impact the formation ahead of the bit. At the point of impact, a substantial portion by weight of the impactors may have sufficient energy to structurally alter, excavate, and/or fracture the impacted formation. The majority by weight of the plurality of solid material impactors may have a mean diameter of at least 0.100 inches, and may structurally alter the formation to a depth of at least twice the mean diameter of the particles comprising the impacted formation.