Russian scientists packed up and left in defeat Friday after top Pentagon officials, citing national security, denied a California company permission to search for gold in Alaska using a high-tech Soviet plane.

The Soviets were working with Tri-Valley Corp. of Bakersfield, a small energy company involved mostly in natural gas production. They planned to explore for gold on Tri-Valley's large forest-covered claim in interior Alaska using a low-flying Soviet aircraft equipped with advanced technology for finding mineral deposits."They've managed to run us out of town," Tri-Valley President F. Lynn Blystone said of the military blockade that prevented the joint venture from taking off. The decision prompted the company's top geologist and five Soviet scientists to leave Fairbanks after a two-week wait for permission to conduct aerial exploration.

"This has reached the assistant secretary (of defense) level," said Al Ptak, a staff member of the U.S. Senate Intelligence Committee working on the issue. "It's bumped up pretty high."

Ptak said national security considerations stood in the way of the project.

Tri-Valley believes it has found what may prove to be a major gold discovery on 64 square miles of interior Alaska southeast of Fairbanks - near several military installations - and arranged to have the Soviets come to Alaska with their innovative airborne technology to look for gold.

Tri-Valley geologist Tom Wilson said the Soviets claim to have a superior technology - unlike anything available in the United States or anywhere else - for geophysical surveys capable of finding mineral deposits without digging up any of the forested land.

The Soviet AN-2 aircraft, which Tri-Valley likened to "a large cropduster," is equipped with instruments that use electromagnetic waves to penetrate 400 meters and reflect according to conductibility or nonconductibility of certain minerals. Although airborne geophysics is not new, the Soviet technology may be better than other advanced systems provided by Canadian and French companies.

The Soviets wanted to show off their equipment and Tri-Valley jumped at the Soviet offer to do what it was unable to do financially or technologically, Blystone said.

Success would mean gold for Tri-Valley and the best advertisement possible for the Soviets looking to drum up business for their highly touted technology. Wilson called it "a win-win situation."