STRUCTURAL CONTROLS ON MINERALIZATION AT MARIGOLD MINE, HUMBOLDT COUNTY, NV: A DETAILED STRUCTURAL ANALYSIS OF THE TERRY ZONE COMPLEX

Mineralization in the Battle Mountain mining district is strongly influenced by multiple deformation events including the Cenozoic extensional deformation that overprints Paleozoic and Mesozoic compressional structures. Marigold Mine, owned by Silver Standard Resources Inc., is an open-pit gold mine located on the north end of the Battle Mountain mining district in Humboldt County, Nevada. It is considered a distal disseminated-type or Carlin-type deposit, with mineralization disseminated within favorable sedimentary beds. The mineralization is structurally controlled, with near vertical faults acting as feeders to deliver the mineralized fluids to favorable beds in the footwall of the Golconda thrust. The gold is dominantly found in structural fractures within the quartzite beds of the Ordovician Valmy Formation adjacent to the steeply dipping faults. In conjunction with an ongoing drilling program, further knowledge of the complicated structural relationships at the surface may contribute to understanding the geometry of potential deposits at depth.

This study will develop a structural model for the Terry Zone Complex open pit using a detailed structural analysis of data collected from the high walls and nearby exploration holes. Laser scanning of the pit walls and oriented COLOG surveys will give us fracture plane orientations that will expand upon data collected from accessible outcrops by field measurements and observations. We expect to determine local paleo-stress regimes and changes in principal stress distributions related to significant structures; and potentially identify older compressional structures that have been reactivated during extension to allow mineralizing fluids to circulate and deposit gold.