EGL Ref: 9215 23 June 2022 Page 3 This report shall only be read in its entirety. File: WAI-985-000-REP-LC-0002_Rev0.docx. 2.2. Waihi Mine site description In 1988 open pit mining of Martha Hill commenced. Open pit mining realised parts of the resource that were previously uneconomic and importantly for the Waihi Operation created a source of earth and rock fill to construct downstream embankment dams for storage of tailings. Downstream embankments are typically the safest type of dam for tailings slurry storage. Other construction techniques such as upstream construction are higher risk if not properly designed, constructed and operated. Martha Open Pit mine is located in the township, centred on a small hill known as Martha Hill. It is shown in Figure 2. A series of underground mines and most of the old historical mine workings are located beneath the eastern side of the Waihi township, and within or immediately adjacent to Martha Open Pit. Further underground mines are located to the southeast of the township towards the Process Plant on the west side of the Ohinemuri River. Figure 2 indicates the locations and names of the underground mines and historic workings. Martha Underground Mine (under Project Martha) is currently being developed and is aligned beneath the south wall of Martha Open Pit. The two TSFs; Storage 1A and 2 and associated rock stockpiles are located to the east of the Ohinemuri River away from the underground working as shown in Figure 1. The tailings storage and rock disposal, and the Water Treatment Plant and Processing Plant area is called the Development Site. The two existing TSFs are shown in the oblique aerial photo in Figure 3, with Storage 2 to the left and Storage 1A to the right. This photo was taken in 2018. FIGURE 2: MARTHA OPEN PIT AND UNDERGROUND MINE LOCATIONS
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