Thermal – 12 V. Appendices D. History of Geothermal Leasing

Report of the Sec. of the Interior under Sec. 7 of Public Law 100-443 on the Presence or Absence of Significant Thermal Features Within Crater Lake National Park, 1992

V. Appendices

    D. History of Geothermal Leasing Near Crater Lake National Park by the Bureau of Land Management

    * IF CONCLUSION IS REACHED THAT THE HYDROTHERMAL SYSTEMS ARE CONNECTED, THEN PROCEED TO SECTIONS VI, VII, and VIII. Attachment 2-1

Geothermal Leasing History and Chronology For

Geothermal Units Mazama I and II

in the Winema National Forest

Adjacent to Crater Lake National Park Oregon

Prepared by the Bureau of Land Management

Oregon State Office. Division of Mineral Resources

Mount Mazama, the collapsed volcano which contains Crater Lake, is often cited in the background and setting descriptions of Crater Lake National Park (CLNP). Mount Mazama is an irregular, east-west elongated, ellipsoidal volcano covering about 100 square miles entirely within CLNP. It is a shield and stratovolcano complex (with certain exceptions) that collapsed from a major eruption some 6800 years ago and created the spectacular Crater Lake caldera. CLNP occupies a roughly rectangular tract that includes additional smaller volcanos and covers about 286 square miles.

Its rocks indicate a history of active volcanism covering more than 400,000 years with the most recent volcanic episode estimated to be about 4,000 years before present. The tectonic/volcanic forces that operated throughout that period still operate today. There are, however, no known hot springs associated with Mount Mazama.

Geologic literature relating to the Mount Mazama area contains information that make it and adjacent lands, an attractive geothermal resource target. Since geothermal leasing is not possible within National Parks, adjoining lands have attracted interest in exploring for geothermal resources.

Lands adjoining Mount Mazama were largely ignored by the geothermal community in the initial surge of leasing from 1974-1980. In the spring and summer of 1982, California Energy Company Inc. (CECI) started to apply for leases on National Forest lands that border the Park. These National Forest lands have been harvested for timber and contain a well developed road network, log landings and clearings that could facilitate access to drill rigs and cleared drill sites.

Additional lease applications in National Forests nearby CLNP continued until the summer of 1985. Total applications reached 110 and covered about 213,199 acres. Presently (5/91) only 46 leases remain covering about 76,516 acres. Leasing interest northwest of CLNP in Douglas and Jackson Counties started in the spring of 1982. The biggest push came in January 1984 when CECI applied for a lease block in the Rogue River National Forest. By the summer of -1985, there were 32 applications – 25 in the Rogue and 7 in the Umpqua National Forests covering 59,942 acres.