Underground Geochemistry
Mantaro collected channel samples across veins in accessible parts of the underground historical workings. Channel samples were from parts of veins that were not the focus of historical mining — as such results are likely to be of a lower tenor than material that was mined.
In total 111 channel samples were taken over a cumulative strike length of several hundred metres. Sampled veins were partly oxidized and locally leached of sulphides.
- A large number of samples assayed above 150 g/t Ag (ca. 5 oz/t Ag) and a significant number of assayed above 450 g/t Ag (ca. 15 oz/t Ag). Sixteen of the 111 underground channel samples assayed above 1000 g/t Ag (ca. 32 oz/t) — of which one sample assayed above the maximum detection limit of 10,000 g/t Ag (ca. 320 oz/t Ag).
- Lead grades of between 1 to 5% and zinc grades of between 1 to 2.5 % are common — although partial oxidation has removed base metal sulphides from many samples.
Deposit Type — Intermediate Sulphidation With Excellent Depth Potential
- Santas Gloria is a silver-base metal vein system — otherwise known as Cordilleran silver-base metal type or intermediate sulphidation epithermal type.
- Globally such deposit-types are attractive exploration targets due to their high grade nature and the large vertical extent of precious and base metal endowment.
- Metal deposition is by non-boiling precipitation which results in deposition of metals over large vertical intervals. Localized boiling at the tops of the system may result in high grade bonanza shoots — which may explain the high surface gold grades in the Pacquita vein system.
- Veins at Santas Gloria are steeply dipping, up to 4 metres wide, and display multiphase and brecciated texture. Multiple fluid pulses and open space created during brecciation are critical in development of high grade mineralization.