HECLA <HL> BUYS STAKE IN GREENS CREEK VENTURE Hecla Mining Co said it agreed to buy a 28 pct stake in the Greens Creek joint venture from Amselco Minerals Inc, a unit of British Petroleum PLC's <BP> BP North America Inc unit. The Greens Creek venture is engaged in final project engineering of a gold-silver-lead-zinc ore body on Admiralty Island, about 15 miles southwest of Juneau, Alaska. Hecla said it estimates its total investment in the project, including its share of production costs, will be about 45 mln dlrs.