A mine developed there was a modest producer, and was in operation well into this century. Production from what was known as the California Mining District continued until about 1970. Most of the district's output was lead, but it also produced copper, zinc and some silver. Interestingly, it was not for silver or gold, the prospector's dream, nor was it for copper, the mineral that was to make Bisbee a boom town a few years later. Dunn had found a piece of cerussite float.
Cerussite is a lead carbonate found in virtually every mining district in the state.
Float is a piece of ore that has been broken from an outcrop by erosion and washed downhill into a streambed. It was silver float that Schieffelin had discovered near Tombstone and it led him to find his rich discovery, for which his brother came up with the name Lucky Cuss. If still rough, its point of origin is nearby. Dunn traced this cerussite to a huge pinnacle of hematite, later known as the Iron Monster. James Duncan, who in 1879 came to the area that was to be Bisbee, first met Dunn at Camp Apache.