New Rambler District

The New Rambler district, just west of Douglas Creek, is located near the south edge of the Cheyenne belt along the Rambler shear zone, an east-trending branch of the Mullen Creek-Nash Fork shear zone. The Rambler shear zone, numerous local northeast-trending shears, and a few northwest-trending faults cut foliated granodiorite, the younger Rambler Granite, and the distorted northeast extremities of the Mullen Creek mafic-ultramafic complex. Primary copper sulfides and gold occur in quartz veins, as fracture fillings, and in zones of brecciation. Significant secondary mineralization, found only in the New Rambler mine, often assayed more than 35% copper. The New Rambler mine first opened as a gold mine in 1870. Copper was discovered in 1900 at a depth of 65 feet, and platinum within the covellite ore was discovered in 1901 (McCallum and Orback, 1968). Estimated production from the New Rambler mine totaled 171.3 ounces of gold, 1,753,950 pounds of copper, 950 ounces of platinum, and 16,870 ounces of palladium (Hausel, 1997). The New Rambler area is now considered an attractive target for platinum group metals exploration.