Shamrock
Although Shamrock Canyon was the site of P.A. Havens' original silver discoveries in 1863 which led to the establishment of Ione, only intermittent work was done through the remainder of the 19th century. In 1907, mercury located by J.L. Workman brought the largest developments to the canyon. The Mercury Mining Company was incorporated in 1910 and the following year expended $10,000 to erect a ten-ton furnace. By the end of 1912, it was claimed that three hundred flasks of mercury were being produced monthly. In 1923 the property was purchased by the J.C. Bradley Mining Company, and after 1925 lessees produced for several years, bringing total production to some 11,000 flasks of mercury.
