Ann: Drill Program Update - Riqueza, page-123

Seals,

OD is an odd beast in the sense it’s setting and mineral assemblage. Bornite is derived from high temperature events whilst chalcocite has two fields of view. There are some deposits where weathering or interaction with ground waters or basin fluids is deemed improbable.

OD was formed where much of central Australia was under water and hence it sits below several hundred of metres of sediments. The interaction with meteoric waters, basin fluids and multiple phases of hydrothermal events creates a very complex ore body. It’s why the textures of OD ore are very complex but the mineral controls are very straight forward with high grades around the central fault with chalcocite/bornite phasing down to bornite/chalcopyrite then chalcopyrite/pyrite.

Most of the earths water is with in the crust stuck in pores until liberated due to changes in state of the rock. So interaction in areas around basins that contain an aquifer network can change the properties if the underlying rock as breccias have open spacing. also note that hydrothermal fluids are mostly made up fluids and gases so interaction with these can change the state of rocks depending on the composition and setting.

It’s a complex and ever changing process, geologists need an open mind and to follow strong processes backed by science.