The Mizpah Mine shaft descended 1,500 feet, more than a quarter of a mile, to underground tunnels supported by square set timbers that helped prevent cave-ins. In this dark environment, miners worked by candlelight, including men who handled timber, drillers known as Cousin Jacks, and muckers who broke up and shoveled out rock, while tools included manual steel drills and air-powered jackleg drills. The Burro Tunnel is a re-creation of one of the many tunnels under the Mining Park, built with heavy timbers and leading to an original mine stope on the Burro Vein of silver discovered by Jim Butler in May 1900. When the vein was first developed, digging opened in this stope and the tunnel carried ore out to cars in a trench outside, and later tunnels connected to the Mizpah shaft so ore could be hoisted to the surface.