Promising find at Martha Hill

Press, 22 June 1981, Page 22

Promising find at Martha Hill

PA Auckland A major low-grade precious metal deposit has been indicated by diamond drilling at the Martha Hill. ■ Waihi. prospect of Mineral Resources N.Z.. Ltd. The results of drill holes so far assayed suggest potential resources of 35 million tonnes of ore body. The company said that 'the results showed recoveries of 2.5 grams of gold and 25 grams of silver a tonne were’likely. On that basis, latest prices for gold and silver quoted on the London Metals Exchange would put a value of at least 51500 M on the Martha Hill reserves should they be proved. Mineral Resources said that each of the first ten drill holes had intersected potentially economic mineralisation to a depth of 250 metres over the entire length of 400 metres tested to date. The company said that, based on testing of a limited number of drill core samples, a recovery rate of 94 per cent for gold and 88 to 90 per cent for silver was expected. The chairman (Dr J. S. Watt) said that the company believed that a significantly greater tonnage could be present. This view was based on the facts that the vein system had been worked to a total depth of 610 metres and

that the deposit continued beyond both ends of the tested portion. Dr Watt said the bulk of the resource appeared to be amenable to underground mining. He said economical modelling was continuously being carried out on the assumption that any eventual mining operation would consist of an underground mine in combination with a small open pit in the early years. He said that although the resource had the potential to become a large, low-grade, low-cost gold producer with

high profitability, it was emphasised that a great deal of additional drilling was required before the resource could be classified as an ore reserve and before mine development could be contemplated. Dr Watt said that evaluation of the prospect by diamond drilling was continuing with two drilling rigs on the site. A further 5000 metres of drilling was planned for the next 12 months. Prospecting at the Martha Hill site is conducted by a joint venture between Amax Exploration N.Z. Inc..