The Meadowbank property is underlain by Archean-age volcanic and sedimentary rocks of the Woodburn Lake Group. The Goose Island and Portage deposits are hosted by magnetite-rich iron formation, while intermediate volcanic rocks host most of the mineralization at the Vault deposit farther north. Both the rock units and the gold deposits are tightly folded and structurally complex, sandwiched between granite plutons.
In all deposits, gold mineralization is commonly associated with intense quartz flooding, and the presence of sulphide minerals (pyrite and/or pyrrhotite).
Deposits
Gold deposits are found along two main structural features that cross the property – the Meadowbank Trend and the Pipedream Lake (Northeast) Trend. The Meadowbank Trend hosts the Goose Island, Portage and Vault deposits, which are the sites of the initial mining. These shallow deposits lie within 7 kilometres of each other. The Pipedream Lake Trend hosts the PDF deposit.
The Portage gold deposit is defined over almost 2 kilometres along a north-northwest strike, consisting of a fold with limbs that extend to the west. The mineralization in the lower limb of the fold is typically 6 to 8 metres thick, and up to 20 metres thick in the hinge area.
Goose Island is 500 metres south of the Portage deposit and similar to it, with a north-northwest strike and a steep westerly dip. The deposit is currently defined over a 750-metre strike length and 10- to 12-metre thickness, down to 500 metres depth (mainly in the southern end). Exploration is extending the Goose Island deposit southward into the deep Goose South and shallow Gosling zones.
The Vault deposit located 7 kilometres northeast of the Portage deposit is table-shaped, with a shallow dip and a defined strike length of 1,100 metres. The deposit has been disturbed by two sets of faults. The main lens is 8 to 12 metres thick, and the hanging wall lenses are 3 to 5 metres thick. Exploration is extending Vault to the south and east.