Corona, Twin Peaks Mine Project Corona Mine in 1963 High levels of mercury and other minerals draining out of two historic mine sites in Northern Napa County prompted the Tuleyome organization to apply for a grant from the California Dept. of Fish and Game to conduct a cleanup project at the mine sites. As part of the California Environmental Quality Act and Napa County permitting process, Archaeological Research conducted a historic/archaeological evaluation of the project area in May 2012. Click here for the public version of this report. Corona The mercury ore areas on the north slope of Mount St. Helena were first discovered in the late 1850’s while prospectors were looking for gold throughout California. By 1861, cinnabar mining claims were being filed in the area. In 1893, the Oat Hill Road was completed through the area connecting the Napa Valley with Lake County. In 1895, H.C. Davey transferred the deed to the Corona claim along with several other claims to the Vallejo Quicksilver Mining Co (James B. McCauley was president and H.C. Davey superintendent). At that time, the only improvements listed on the property were “a good trail almost wide enough for a wagon road… Also a house, blacksmith shop, etc.” of a value “not less than $1,000.” The Vallejo Quicksilver Mining Company operated the Corona Mine from 1895 until 1906. Work at the mine stopped due to a heavy winter that overwhelmed the pumps used to keep the mine dry. A “20-ton fine-ore furnace” was constructed at the Corona in 1896. In 1901, stockholders voted to construct the 50-ton capacity Scott Furnace that is still standing today. Though he never worked the mine again, McCauley owned the Corona until his death in 1943. He leased out the claim to various individuals and companies to be worked and it appears that the mine was worked in 1911, 1916, and 1939-44. In 1941, the Corona was subleased by a group headed by Mr. Tuttle. This group installed the small linked rotary furnaces and condensing system located just south of the Scott Furnace. Hugh C. Ingle, Jr. leased and operated the Corona Mine from 1957 to1972. In 1963 and 1964 he installed a Gould rotary furnace. He worked the mine until 1972.It appears that Don Emerson obtained the mine from the McCauley estate and owned it until it was purchased by John Livermore in 1995. Twin Peaks In 1904, Hamlin W. and Edward L. Herrick staked the Twin Peaks claims over older claims that had lapsed. Herrick sold the Twin Peaks claim to B.A. and A.A. Wilson and Louis Douglas Fay in 1915. By 1917, Fay had produced 275 flasks of mercury. During this period, the ore was being obtained from both the upper and lower adit levels. Two “D” retorts were being used to process the ore.The next report of Twin Peaks operation is in 1942, when Fay installed a 60-ton rotary furnace before discovering that no new ore was available. Fay sub-leased the Corona, reopened several areas of the mine and trucked ore to the Twin Peaks furnace. They produced $48,000 in mercury before stopping operations in 1943.