the death of jason shalue also led robert handa to look at the danger of abandoned mines in the south bay. and in 2006, he visited one of those mines in san jose. >> reporter: john slenter conducts tours of the quick silver mines deep in the hills of south san jose. >> we're now traveling on mine hill road which was the original road that led up to the mining area. >> reporter: the mining operation started in the 1860 to dig for cinabar used by prospectors to separate silver and gold. slenter took me into what is left of one of the mines it was a fascinating and some what eerie look under ground. >> we're heading toward the entrance to the san cristobal which was started back in 1866 this was used right up into 1976 they were still taking material out here. take a look at this here. hard rock mining. they had to hand drill holes into the rock and in the early days they used black powder. placed it into these holes they drilled and then set their fuses and blasted it. they're biggest problem here was not so much bad gases or bad air, but it was water. water was their biggest enemy as t