Despite significant gold and platinum mining since the 1880’s, it wasn’t until the 1940’s that gold and base metal mineralisation at Sorpresa was first discovered. A local prospector George Green recognised a gossan outcrop in what is now the northern part of Sorpresa and dug a shaft to 53 feet. Rock chip sampling of mullock in 1969 by Platina Developments returned silver results “in excess of 4 Oz /ton Ag” and gold results up to 6g/t Au. Platina drilled two percussion holes at the George Green Prospect however results cannot be located. Follow-up sampling (rock chip) at the George Green Prospect by Rimfire in March 2009 returned gold up to 8.84g/t Au and renamed the prospect “Original Sorpresa”.
George and his son Noel, pictured here, continued prospecting and discovered the “Golden Green” mine.
Subsequent exploration 1.2km SW by Rimfire involving rock chip, soil sampling and auger drilling defined a curvilinear Gold anomaly @ > 20ppb Au over a 1.7km strike. The peak gold values were then trenched revealing significant near surface high grade Gold (9m @ 4.9g/t Au) with peak values up to 87g/t Au at Trench 31.
Drilling of the auger geochemistry rapidly defines shallow high grade oxide Au / Ag mineralisation at and near surface within 6 structurally controlled oxide to transition zone pods defined along the gold anomaly. The pods are subsequently separated into various targets with the southern portion of the Sorpresa system termed Trench 31, moving north into the Boundary Gate area, Boundary Gate East, Join Up, Roadside Au+/-Ag “Plunging Shoot” and Roadside North which is silver dominant.
Detailed geophysics utilizing aeromagnetics, ground gravity and induced polarization (I.P.) techniques were then deployed to enhance targeting and understanding of the gold pods, and with later targeted diamond drilling, high grade primary mineralisation was intersected (Significant Results).
Further RC Drilling successfully targeted down dip extensions to 500m down dip, (200m vertical below surface at Roadside) and 3D modelling facilitated a maiden JORC 2012 mineral resource estimate.