Sierra Nevada Gold to follow-up bonanza 1,270g/t silver hit at Blackhawk project

Exploration company Sierra Nevada Gold (ASX: SNX) will review the potential for a large, high-grade epithermal silver-dominated vein system at its Blackhawk project in the US.

The plans are a follow-up to drilling beneath the Endowment mine, which returned 0.5 metres at an impressive 1,270 grams per tonne silver from 256.5m (21.5% lead and zinc).

The company has previously identified a large and high-grade intermediate sulphidation epithermal silver-gold-lead-zinc vein system at the mine, which it says is likely related to a large porphyry system located immediately to the south.

Partially coincident with this, the Blackhawk vein system covers about 5 square kilometres and is open under cover to the north and north-east, with 22.5-line km of veins identified to date.

Extensive network

Executive chair Peter Moore said the results were very promising and come from a vast and extensive vein network.

“This known mineralisation has sat largely untouched since mining ceased in the area in the 1920s,” he said.

“We have two shallow oxide resources that have not been defined to a JORC-compliant level and provide us the opportunity to deliver value from an existing project with further drilling and mineral resource definition.”

The company is preparing to drill a 20-hole campaign using modern exploration techniques.

“We expect to return further high-grade results at Blackhawk and shape this as a company-making discovery for Sierra Nevada,” Mr Moore added.

Historic mining location

The Blackhawk epithermal project hosts eight historic mining centres with main production coming from the Endowment, Silver Gulch and Blackhawk mines.

Endowment was discovered in the 1860s and the majority of mining was completed by the 1880s, achieving reported production of 70,000 ounces of gold equivalent.

Mining ceased in the 1920s due to an inability to process sulphide ores and prevailing depressed economic conditions.

American Gold Resources conducted a field programme in the late 1980s that outlined two shallow oxide gold-silver deposits at Silver Gulch and Morning Star.

Rock chip sampling across the project by Sierra Nevada Gold returned grades of more than 1% silver and demonstrated the metal’s widespread distribution across the camp.