There's relatively little to differentiate "Gold Diggers: The Secret of Bear Mountain" from the usual adventure-themed "family" film other than the fact that its adventurers are girls. If not for the talents of Christina Ricci and Anna Chlumsky, the whole affair would be an excruciatingly adolescent exercise in formulaic genre storytelling. Backed by handsome production values and a rousing score by Joel McNeely, director Kevin James Dobson almost succeeds at masking Barry Glasser's glaringly pedestrian screenplay. But even with this fancy wrapping "Gold Diggers" quickly becomes dull. Starring Christina Ricci and Anna Chlumsky. Directed by Kevin James Dobson. Written by Barry Glasser. Produced by Martin Bregman, Rolf Deyhle and Michael S. Bregman. A Universal release. Adventure. Rated PG for mild language and thematic ele- ments, including a child's exposure to domestic abuse. Running time: 93 min.