All the gold deposits are considered to be typical of epithermal vein gold-silver deposits.
All known Au and Ag mineralisation in Waihi is confined to veining or vein fragment within hydrothermal eruption breccia. The major mineralised veins are typically coincident with dip-slip, normal faults believed to have formed in an extensional setting related to early, back-arc rifting of the TVZ dated at ca.6.1 Ma (Mauk et al 2011).
Some of the main mineralised veins within the Waihi area include the Martha vein system (which includes the Martha, Empire, Welcome, Royal, Edward, Rex and Albert veins among many others) in the Northwest (NW) and the Correnso, Daybreak, Union, Trio, Amaranth, Favona, Moonlight and Gladstone veins progressively SE.
Martha
The Martha vein system is the largest and most documented of the vein networks in Waihi. It has historically been mined from underground and more recently mined as an open pit and is currently being mined from underground once again. The veins are numerous and form a large network that extends for more than 1600 m along strike and 600 m below the surface. The vein network although complex in detail, simply comprises the dominant southeast-dipping Martha vein and several northwest-dipping hangingwall splays including the Empire, Welcome, Royal and Rex veins. The Martha vein is the largest vein structure reaching up to 30 m in thickness in places but averages 6 to 15 m wide. Increased vein widths are ........
