Dancing Down Below.

WHAT IS THE NEXT BEST use for a sixteenth-century silver mine? How about a twenty-first century, state-of-the-art discotheque, complete with light show and champagne bar? That is what tourism officials in Zacatecas, Mexico, think. So instead of the clang and clash of hammer blows on steel chisels, what today echoes from the main shaft are the silky sounds of Ricky Martin and Lionel Ritchie.

The El Eden mine that snakes on seven different levels trader Zacatecas has been that mountain town's raison d'etre ever since the digging began in 1586. At the height of production in the late colonial period, it was offering up over four pounds of silver and seven ounces of gold for every ton of ore extracted. Some 25 percent of the New World's total silver output came from El Eden over two centuries.

But production and technological improvements lagged during the political turmoil of Mexico's revolutionary years. Pancho Villa's "taking of Zacatecas" in a bloody battle on June 23, 1914, is commemorated on a nearby hilltop. Flooding of the mine's lowest two levels and the city's expansion onto the flanks of the dangerously undermined "El Grillo" hill, site of the main veins, forced El Eden into mothballs in 1966.

And there it sat for ten years, until it was reopened to public visits. A nearly two-thousand-feet-long train track was built into a fourth-level addition to take tourists underground. Once inside, one of the town fathers looked up at the soaring rock-hewn vaulted ceiling of what had been the crushing and milling chamber and said, let's dance for a good cause! The disco's fifty-peso cover charge is now split equally between a social-service agency and the tourism office.

Felipe Martinez, a licensed mining engineer with the Zacatecas Tourism Office, is the man charged with making sure youthful revelers can dance safely a thousand feet underground. "Weekends we are always at full capacity," he says, "with people sitting outside waiting theft turn to go in." Getting everyone out promptly at the 3 a.m. closing time is not a problem however. "The mine's air temperature is a damp 12 degrees Centigrade," he notes. "The minute you stop dancing, you feel the cold."

The disco first opened twenty years ago with minimal shoring of the original rock face. "Dust and stones were constantly shaking loose," Martinez notes. "Everyone should have been wearing hard hats instead of party clothes." Last year the disco underwent a complete facelift. A parquet dance floor, booming sound system, and plush banquettes were installed. The disco was rechristened as the "El Malacate," or the Winch.

Business has never been better--quinceaneras now compete with old timers to boogie the night away. Disk jockeys Jesus Torres and Victor Morillo spin tunes from theft Swiss-engineered control booth like alchemists of old, and everything from Dom Perignon to Dos Equis flows like underground rivers of gold.