A thorough understanding of the soil and rock conditions beneath the ground surface is critical for a geotechnical engineer to effectively design building foundations or earthen structures such as dams or stabilized slopes. Methods and equipment vary through the Coastal Plain, Piedmont and Karst geology encountered in the mid-Atlantic region. Standard penetration test (SPT) borings and rock coring are the most common method of sampling utilized. Sampling can be advanced using wire line rock coring, hollow stem augers or mud-rotary techniques. CGCG has several different types of drill rigs that can used for SPT sampling, including truck mounted, all-terrain vehicle mounted, track mounted and skid mounted rigs.