Bureau of Land Management officials have denied permission to mine mineral claims that have been in existence for 30 years in the Mount Hillers Wilderness Study Area south of Hanksville, Garfield County.

The decision could spark another confrontation between environmentalists and angry Garfield County residents, who have long contended that environmental rules are damaging the economy.A mining plan was submitted by an operator the BLM did not name, seeking to develop 40 adjacent mining claims and one mill site. The claims, "Happy Bottom," "Henry C.," "Ann B. No.1," "Judy" and "Eva J," were all located between 1955 and 1957. The mill site claim was filed in 1964.

All the claims were made before passage of the Federal Land Policy and Management Act of 1976, under which wilderness study areas were designated.

The operator wants to prospect and develop existing mine workings and explore for minerals on adjacent areas within the claims. Digging would be necessary as minerals are known to exist underground in the region.

In order to move exploration gear, mining equipment and ore, a trail would be improved and new routes constructed. Altogether, 3.3 acres in the study area would be disturbed.

But BLM State Director James M. Parker denied the request, saying it would impair the suitability of the land for possible wilderness designation. Mining scars could not heal for several years and trees would need up to 17 years to grow back.

Federal rules say developments can't be allowed in wilderness study areas if they cannot be reclaimed to a "substantially unnoticeable" state before the Interior Department makes recommendations to the president about whether the land should be permanently protected. That is supposed to be made for Utah study areas on Sept. 30, 1990.

"The non-impairment criteria cannot be met due to the short time period before the secretary's wilderness recommendations are to be made to the president," said a decision document signed Oct. 21.

Therefore, under existing rules, only hand tools would be allowed in the study area.

Under the proposal, about three-quarters of a mile of new trails were to be built and up to 100 bore holes were to be drilled.

A BLM assessment says that a 200-yard section of the trail inside the wilderness study area already is graded. It said this violated federal rules because "there was no plan of operation approved."

At the point where the grader stopped, it was because the equipment "was unable to continue because of the steep slope and rocks." Above it, the trail is impassable to vehicles.

Above the bladed section, the trail was hand-cleared for about 300 yards. Some of this clearing seems to have happened at least two or three years ago, the report said.

The rest of the trail, about one-half mile, has not been cleared, according to the report.

The topography is rugged, with steep peaks divided by narrow canyons. The surface area of the proposed drill trails is mostly slopes of gravelly loam covered with talus debris, which the document states would support a good stand of trees.

The wilderness study area offers opportunities for hiking, sightseeing, backpacking, camping and nature study. About 18 miles of hiking trails are present in the study areas, where about 19,000 acres are in a natural condition.

"The general area of the proposed activity contains about 3.5 miles of trails, two mile shafts, two mine tunnels and two abandoned cabins," said the assessment.