VIEILLE MONTAGNE SAYS 1986 CONDITIONS UNFAVOURABLE A sharp fall in the dollar price of zinc and the depreciation of the U.S. Currency created unfavourable economic conditions for Vieille Montagne SA <VMNB.BR> in 1986. It said in a statement that the two factors led to a squeeze on refining margins and an 18.24 pct fall in sales and services income despite an unchanged level of activity. Vieille Montagne, which is actively pursuing a restructuring program, reported a 198 mln franc net loss, after 187 mln francs in provisions for the closure of an electrolysis plant, compared with a 250 mln franc net profit in 1985.