May 2018 Project Martha – Historical & Archaeological Background 87 Reefs of the Waihi goldfields Only the Martha Hill and Union-Silverton systems proved to contain gold and silver in economic quantities (McAra 1988: 22). The principal reefs of the Waihi goldfields fall into two main groups: the Martha Hill system which contained the Waihi and Grand Junction mines, and the Union -Silverton Hills system which contained the Union and Silverton mines (ibid). Only a small area of the quartz andesites are exposed on the surface, nevertheless the general positions of the underground reefs located by 1914 are shown in Figure 69. The whole structure formed a network if veins, with the richest concentration near No. 1 Shaft. All mining on the Union- Silverton Hills system had ceased by 1902, making the Martha Hill system by far the most important. As already outline (above, Historical Background) the Martha system was divided into three main parts, with Grand Junction holding the western and eastern end reefs and Waihi Gold Mining Company the middle portion reefs. The Waihi Hill system reefs (moving north-west to south-east) were: North, Number Two, Martha North Leader, Martha, South Branch Martha, Welcome, Welcome Right Branch , Surprise, Bell Crosscut, Magazine, Victoria, Albert, Alexandra, Jellicoe, 208 Foot, Prince, Empire, the letter reefs (B,C,H,I,J,K and L), Princess, Dreadnought, Edward, Royal North Branch, Royal, Rex, Ulster. Other reefs include the Reptile and Scorpion crosscuts. The most important reefs in the Waihi Mine were Martha, Welcome, Empire, Royal and Edward. Only a relatively small amount of ore in the Waihi Mine was accessible from surface adits or horizontal tunnels so shaft-sinking was a fundamental aspect of mining and involved highly developed equipment for pumping, winding and construction (ibid:173). The historical gold mining process, ore treatment and gold recovery methods are well documented in McAra 1988.
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