The Shumagin Trend is a 9km long, NE Striking intermediate sulfidation epithermal complex of sub-vertical, multi-episodic, cockade-colloform-crustiform banded quartz-adularia-rhodocrosite-green clay stockworks, veins and breccias. The Shumagin structure is a steeply SE dipping fault which separates a crystal-lithic tuff hanging wall from a porphyritic andesite footwall extending from the Main Breccia showing in the NE to the Aquila Zone 9km to the SW on the coast of Unga Island. Approximately half way along the Trend there is an upstanding volcanic lithocap called Orange Mountain.
Drilling to date on the SH-1 Zone Zone has identified a SE dipping, NE plunging shoot of high grade gold + silver which is open on all sides:
The SH-1 Zone lies to the northeast of Orange Mountain and comprises Bunker Hill – Main Breccia – Rhodo Breccia surface anomalies. It is between seven to ten metres wide (true width) and enveloped by pervasive silicification and anomalous quartz-sericite-pyrite veins and stockworks occurring as a consistent halo to the system and commonly extending for more than 10m into the hanging wall.
Gold + silver mineralization is contained in banded, crustiform-colloform textured veins and vein breccias that contain very fine grained laminations of green clay + rhodochrosite along with minor disseminated pyrite-galena-sphalerite and scarce chalcopyrite.
The system has been localized along the Shumagin scarp, a northeast oriented, steeply southeast dipping contact between a footwall of coherent Eocene-Oligocene basaltic-andesite and a hanging wall of massive ± reworked dacitic pyroclastic flows and overlying epiclastic sediments. A complex of steeply-dipping phreatomagmatic breccias and dikes were also emplaced along this contact and are interpreted as pre- to syn-mineral.
A moderately brecciated, sub-vertical dike interpreted as pre’ to syn-mineral is entrained within the system, variously bound by’ and cut by a high-grade gold vein as seen in drill holes 15SH011 and 15SH012. Drilling in 2011 intersected the vein system ~190 metres down plunge towards the northeast (11SH010: 0.55m of 738g/t gold & 408 g/t silver). The relationship between dike and mineralization has been noted in several drill holes and suggests a connection between phreatomagmatic breccias, dike emplacement and localization of high-grade gold + silver mineralization.
Further drilling in 2014 and 2015 successfully inersected the vein system in eight holes and proved the continuity of the system to depth and along strike with assay results including: 1.9m @ 202g/t Au, vand 2m @ and 35.3g/t Au over 2m.
In 2016, Dr. Jeffrey Hedenquist, a globally respected epithermal expert, visited Unga and provided a technical report indicating strong upside potential and favorably compared the project with other high grade, economic epithermal gold systems. In addition, Redstar completed an exploration program along the Shumigan Trend towards Orange Mountain to the southwest including: geochemical sampling, detailed structural mapping, reconnaissance mapping, surface bedrock sampling and exploring other known prospects within this 240km2, district-scale property.
Later in 2016, Redstar completed a 1,500m drill program that extended the overall strike of The Main Breccia zone from 300m to 950m.
In 2017 a follow-up geophysics program and subsequent drilling showed that the structure continues along strike to a minimum length of 1,350m.
Plans in 2019 include extending geophysics to the SW in order r to trace the structure beneath more recent volcaniclastics.
The photo below illustrates the Shumagin Vein system with annotations showing the surface exposure of the vein and the sites of the Phase One drill hole collar positions.
A major goal of future drill campaigns will be to continue with additional step-out drilling towards the northeast for an additional 350 metres where exposures of the Shumagin vein system returned high-grade intercepts at shallow depths from drilling during the 1980's (DDH26: 37.7g/t gold & 20.6g/t silver over 0.76m and 11.48g/t gold & 15.1g/t silver over 1.21m).
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