State and county officials have decided to review mineral leases for the Great Salt Lake and will not issue any new leases until a study is completed in May 1991.

The Great Salt Lake Technical Team, a 12-member board of government officials, met Wednesday and agreed to hold a moratorium on new leases.Current mineral leases on the lake are a patchwork of different terms, royalties and lengths, State Lands and Forestry Minerals Section Manager Ed Bonner said.

And some leases are undervalued and are more favorable to the companies than the state, he said.

"We felt that there was a lot more economic value than we were seeing," Bonner said.

Since the 1940s, state and federal government officials have wrangled over control of mineral rights on the lake and its shifting shoreline. As laws changed and U.S. Supreme Court rulings were made in favor of the state, the leases reflected the changes, Bonner said.

Some older leases do not reflect the true economic value of the minerals, do not have renegotiation clauses and run from 20 to 50 years before they expire, Bonner said. And there's a wide disparity between lease agreements.

"I think the companies are aware that there are some problems" with the leases, he said.

The study will be conducted by the Utah Bureau of Economic Development and will review lease terms, economic conditions and other states' mineral salts leases.

Bonner said the study will give government officials a basis for "tightening up our leases" and more fairly negotiating future mineral agreements.

Current mineral leases will be unaffected by the moratorium. Companies holding leases for the lake's minerals include Great Salt Lake Minerals & Chemicals Corp. and Magnesium Corp. of America, formerly AMAX.