Black Wonder Mine is two miles southwest of Pine Grove just east of Highway 88. Work started at this mine in 1931 under a partnership consisting of Bert Caldwell, Nick Contini and Dean Wiley. In 1933 and 1934 it was sub-leased to Weise and Holmes.
During 1933, 800 pounds of ore containing $ 173 worth of $ 20.67 per ounce gold was shipped to the smelter of Selby, California , according to Mr, Caldwell. The mine was shut down in 1935 and has been idle since that time.
