The Rio Tinto/old Giroux property embraces 9 patented mining claims on 166 acres in the town of Darwin Ca.( Rio Tinto, Mammoth, Magnet, Mexican, Republic, Kingston and Toga 1, 2 and 3 claims). According to historical documentation from 1890 to 1908 mining produced of Cu-Pb-Zn was mined from a 200-foot shaft with a 95-foot cross cut and 70-foot inclined shaft.
My grandfather who was a prospector and miner obtained this property in 1946. He was unable to work on it due to other obligations and then declining health. After he passed away my grandmother leased the property to a single man who had a Company called “Harvest Gold Corp.” in 1992. He canceled the lease in 3 years later due to lack of exploration funds and inability to raise capital. In the short time he leased the property he did a chemical analysis on samples which showed Paleozoic limestones in a thrust fault contact with the Darwin Diorite stock, skarn mineralization with copper and gold in and near the thrust surface. He thought that a hidden copper/gold target was present but was unable to explore further. The property has not been worked on since.
In 1980 a report written by the University of Western Ontario for potential Tungsten occurrences in the Darwin Hills, in the Giroux/Kingman area a continuous band of garnet skarn 2500 feet long and up to 250 feet thick contains disseminated copper oxides and sulfides that had been exploited. The overall skarn band was extensive to the depth well beyond the bottom of the Giroux shaft (203 feet). Dumps at the various workings contained jasper/limonite/copper oxide material as well as a minor amount of gold and silver recorded. Another of these areas at the old Giroux and Kingman mines has thick extension skarn zone with good depth potential disseminated copper minerals and a stratigraphic and structural setting comparable to many of the major W-Cu deposits in the Yukon. The report said the area needed careful examination as a Cu and possibly W, Au, and Ag prospect.
Location and Access:
The Darwin Hills are a NW trending range immediately east of the town of Darwin, CA. Which is 36 miles southeast of Lone Pine, California and 40 miles west of Death Valley in Inyo County, California. It is reached by taking State Highway 136 east to the intersection of State Highway 190 at the south end of dry Owens Lake, then proceeding on Highway 190 approximately 13 miles to the Olancha Darwin Road turnoff. Turn south on Olancha Darwin Road and travel 5.5 miles to the ghost town of Darwin. The Rio Tinto claims are easy to access from a dirt road on the outskirts of the town of Darwin.
The Darwin district is an area of low arid hills within the Darwin Plateau in west central Inyo County. The 9 Rio Tinto Consolidated claims encompass 166 acres of that district.
Paleozoic limestones in a thrust fault contact with the Darwin Diorite stock, skarn mineralization with copper and gold in and near the thrust surface. It is thought that a hidden copper/gold target is present. The Darwin Hills was known for producing lead, silver, copper, zinc, and tungsten.
There is a rich history of many individual mines in the Darwin area. They are distributed throughout an area encompassing approximately 9 square miles and called the Darwin District Mines. They have operated intermittently since 1875 and have been the principal lead producer of California with approximately 29 million dollars in lead, silver, zinc, tungsten and copper replacement deposits. The location of many deposits in veins and composition of the associated skarn and kornfels makes the Darwin W deposits unlike any major deposit described in the literature.
Currently there is activity on one mine in the Darwin district. A company has invested heavily in it for the past 20 years. There is a record high profitability of 40 percent direct shipment of ore and four to one ore to waste ration. Primary producer of tungsten, Zinc, Silver and lead. The mine contains over 138 miles of drifts and 3.2 million tons of ore and waste mined.