A review of high-altitude drilling

In 1979, we began a program of retrieving ice cores from glaciers located at high elevations in low-latitude locations for use in past climate research. The high-resolution records of past climates obtained from these cores provide a unique link to past climates outside the Polar Regions.

Since 1986, coring has been successful at various locations in South America and across the Tibetan Plateau using a combination of electromechanical and thermal drills to reach depths of up to 309 m and working altitudes of up to 7200 m. The wide variety of environmental and ice conditions including "brittle ice" has resulted in the development of a drilling system that can be use a variety of power sources and drill ice that varies from -20^oC to near 0^oC. Because of the brittle ice phenomenon, we have experimented with ways to improve core quality in the brittle ice zone. We also developed shelters, core processing equipment, and shipping containers capable of returning ice core to the lab in a frozen state. Lessons learned from these excursions are discussed.