MADRID — Paramount’s 3D toon “Tad, the Lost Explorer” has discovered box office gold in Spain. A comedy-adventure yarn about a construction worker who becomes a daredevil treasure hunter in Peru, “Tad” has topped the B.O. chart five weeks running through Sept. 30 — a feat last achieved by another 3D film, “Avatar” — on its way to cuming €12.8 million ($16.5 million).The biggest Spanish film this year, and the highest-grossing homegrown animated film ever in Spain, “Tad” fell just 6% in its fifth frame. With no rival tyke toon on the horizon, it has a sporting chance to pass “The Intouchables” ($21.1 million) as Spain’s numero uno movie of 2012. El Toro Pics, Lighting Entertainment and Ikiru Films produced “Tad,” alongside two powerful media congloms: Telecinco Cinema (the film arm of Spain’s biggest commercial broadcaster, Mediaset Espana), and Telefonica Producciones y Media Networks. Mediaset Espana gave “Tad” a colossal push across its seven channels, and the results suggest that if an indie film is good enough and promoted at studio-pic levels, it just might yield studio-pic results. Both Toro’s Jordi Gasull and Telecinco Cinema CEO Ghislain Barrois agree that while some of the explanation for “Tad’s” success has to do with promotion, some has to do with the film as well. Gasull says the pic is generating excellent word of mouth, while Barrios notes that it may be striking a nerve among those hit by Spain’s economic crisis. Slack-jawed and cringing, Tad is no Harrison Ford. But somehow, he wins the day. “This is a great time to bring Spanish audiences a hero who’s just a regular guy thrown into an incredible adventure,” Barrois says.