Select drilling equipment that is properly suited to the site conditions prior to mobilization of equipment and crew to the field. Generally, truck-mounted drill rigs can access most sites. However, drilling operation in difficult site conditions such as soft ground, swampy areas, sloping/steep ground may require use of track-mounted, or all-terrain vehicle (ATV) mounted drill rigs. Drilling operation over large water bodies may require barge drilling. Barge drilling typically will require heavy planning and coordination for proper selection of barge capable of supporting the drilling rig, launch locations/sites, vessel for transporting the barge, potential permitting requirements, etc.

Select drilling methods that cause minimal disturbance to the samples obtained, yield good quality SPT results, and suitable for the subsurface conditions. Drilling methods such as wash and jet boring, airrotary drilling, etc., generally tend to cause disturbance and may yield unreliable samples and SPT results. Hence, take drilling methods into consideration if data is used for design applications on TxDOT projects. Dry and wet rotary drilling methods are common methods in TxDOT projects. In bedrock or rock masses, perform rock core drilling with diamond bits to obtain continuous rock core samples for evaluation of intact rock as well as rock mass properties. Selection of drill bits and core barrels should be such that the tools selected yield good recovery and daily production, cause minimal disturbance to the core samples recovered, and appropriate for the anticipated characteristics of the rock mass or deposit. The selection of proper drill bits and core barrels suitable for the anticipated characteristics of the rock mass or deposit is the responsibility of the driller. Hence, the driller must be experienced with the selection of proper equipment and tooling necessary to yield good recovery.