Hecla Mining Co. says it will close a southern Utah silver mine next week, idling 48 workers.

The known ore body at the Escalante mine, 40 miles west of Cedar City, has been mined out, and exploration efforts to find new ore have been unsuccessful, Hecla said.Hecla's mill at the site will remain open until late 1990, processing a large stockpile of ore accumulated during the past few years. The 850-ton-per-day mill will continue to employ 41 people, Hecla said.

Hecla said 43 hourly and five salaried employees will lose their jobs Dec. 30, including mine workers, electricians and administrative workers.

"The Escalante Unit has been a good property. The employees there have done a good job and we've enjoyed working with the people in the area," said Ralph Noyes, vice president for metal mining.

"Unfortunately the ore body has now been exhausted and the mine must be closed," said Noyes.

Hecla budgeted $231,000 this year to find more ore at the mine.

The Coeur d'Alene company - which mines silver, gold, clay and other industrial minerals - acquired the Escalante mine in its merger with Ranchers Exploration and Development Corp. in 1984.

The mine has produced about 15.5 million troy ounces of silver during its life, including 2.3 million ounces last year, plus 1,080 ounces of gold from 294,000 tons of ore milled.

Hecla Chairman and Chief Executive Arthur Brown said last month the firm will continue its expansion into gold, industrial and speciality minerals like beryllium, gallium and germanium - while de-emphasizing silver production. Brown said Hecla is considering buying a germanium operation near St. George.