Discovery of polymetallic porphyry at the Silver Queen, British Columbia using airborne EM and TITAN-24 DCIP and MT surveys

Abstract

Airborne electromagnetic, ground direct current and induced polarization (DCIP), and magnetotelluric (MT) surveys have extensively been used in mining exploration and more particularly for the exploration of base metal mineralization. The continuous development of geophysical techniques with advances in the instrumentation and signal processing and the recent development of robust 3D inversion algorithms make possible the detection and accurate delineation of deep-seated mineralization of economic interest. Recently, a deep-penetrating TITAN-24 DCIP and MT survey was conducted over the Silver Queen project area, located in British Columbia, Canada in two phases (2011 and 2012, respectively) by Quantec Geoscience Ltd. on behalf of New Nadina Explorations Ltd. for the exploration of porphyry-style polymetallic mineralization. The ground survey was carried out as a follow-up to the helicopter-borne z-axis tipper electromagnetic survey flown during the spring of 2011 by Geotech Ltd. with the aim to delineate favorable areas for the exploration of porphyry-style deposits. A deep-seated significant zone of anomalously high chargeability occurring in coincidence with a conductive zone was detected by the ground DCIP and MT survey. Drill-testing based on the 3D inversion results of the data led to the discovery of a new significant deep-seated porphyry-style mineralization. The discovery drillhole contained visible disseminated to semimassive sulphide mineralization, gold and molybdenite over 350 m for a total drillhole depth of approximately 800 m and occurs in association with a significant mineralized stockwork zone open at depth.

Three-dimensional imaging of a Ag-Au-rich epithermal system in British Columbia, Canada, using airborne z-axis tipper electromagnetic and ground-based magnetotelluric data

“…However, porphyry-Cu and related epithermal deposits generally exhibit only a modest contrast in electrical resistivity due to the lower abundance and disseminated distribution of the sulfide minerals. Additional field studies are needed to determine the most effective exploration approach for this type of deposit (Oldenburg et al, 1997;Hoschke, 2008;Bournas et al, 2013).…”