The Scraper Springs Property consists of 276 unpatented mineral claims and 405 hectares (ha) (1,000 acres) of patented land, covering approximately 2,710 ha (6,700 acres) in total. The Property is 72 kilometers (km) (45 miles) north of Battle Mountain, Nevada, and is located directly on the northern extension of the Carlin Trend of gold deposits. Subject to net smelter royalties Columbus controls 100% of the Property.
The Property covers a volcanic center cored by a quartz monzonite intrusive cutting Upper Plate Vinini Formation cherts and siltstones. Highly altered volcanic rocks, coeval with the intrusive, lie marginal to the central core, with Vinini Formation exposed in erosional windows below the volcanic package.
The area was first explored by Western States Minerals, which drilled 13 holes to a maximum vertical depth of 198 metres (m) (650 feet). Western States drill hole SS-1 encountered a strongly anomalous gold zone from 93 to 143 m (305 to 470 feet), including 26 m (85 feet) of 0.86 grams/tonne (g/t) Au from 98 to 123 m (320 to 405 feet). High assays over 5 foot intervals were as high as 1.9 g/t. The gold is hosted by cherts and siltstones of the Upper Plate Vinini Formation alongside the quartz monzonite intrusive rock. This gold mineralization has a Carlin-type geochemical signature.
The intrusive body is dated at 38.9 mybp, which is the age of igneous rocks associated with gold deposits elsewhere on the Carlin Trend. A detailed ground magnetic survey indicates that the poorly exposed intrusive body is approximately 1,676 m (5,500 feet) long, and 671 m (2,200 feet) in diameter. Detailed geologic mapping has been completed along with soil and rock sampling. Numerous gold anomalies were discovered in the grid soil sampling, and rock values to 0.8 g/t were found along altered structures.
Twelve widely-spaced rotary holes were drilled, mostly to depths less than 183 m (600 feet). One hole was drilled to 579 m (1,900 feet), and encountered altered carbonate rocks of the Lower Plate of the Roberts Mountain Thrust at a vertical depth of 503 m (1,650 feet). The Lower Plate rocks were mostly silicified, and contained anomalous gold, copper to 0.2% over 15 m (50 feet), and zinc to greater than 1% over 1.5 m (five feet) intervals. Many of the other shallow holes had anomalous gold, zinc, and arsenic.
Three types of targets exist at Scraper Springs: 1) disseminated zones in the altered volcanic package, 2) Carlin-type gold deposits distal to the intrusive body, both in Vinini Formation and in the Lower Plate package at depth, and 3) either porphyry-hosted base-metals or polymetallic, gold-bearing skarns associated with the intrusive itself.
