Discovery of the authigenic nature of the porphyroid underlying the Peko gold-copper orebody at Tennant Creek led to the realisation that synerectic desorption of adsorbed trace metal species during diagenesis and consolidation of this large volume of porphyroidal rock had been the source of the economic mineralisation.
Recognition of this relationship between syneresis in porphyroidal source rocks and economic mineralisation resulted in the discovery of five new mines (locally) from the first fifteen prospects drilled.
Applied generally this new understanding led to further discoveries. By 1975 an additional new mine and a total of thirty-three mineable orebodies had been discovered at Tennant Creek, a new mine for an additional tungsten orebody at King Island, and four major orebodies resulting in new mines at Parkes, NSW and Ranger in the Alligator Rivers province, NT. This outstanding success established a significant lead in cost effective exploration and attracted the attention of competitors.
Sir Roderick Carnegie, Chairman, and Mr. John Collier, executive responsible for exploration in CRA, commissioned independent consultants to compare the effectiveness of Australian mineral exploration programs and to identify the factors leading to success.
McKinsey & Company, Inc. Management Consultants, New York, conducted a survey and furnished a report dated 20th June 1975 entitled “Successful Management of Mineral Exploration in Australia”. Participating companies were provided with copies.
This report did not identify participants by name but it provided information on exploration costs per find and the gross value of metal found per exploration dollar expended to find it. Geopeko’s exploration costs included ore definition drilling to the point where a decision could be made to mine the deposit. Its internal figures at the time showed $4,254,507,000 in gross metal value had been discovered for a total exploration cost of $15,464,061. This is a ratio of 275.12, which clearly identified the position of that company in the comparative report.
The significance of the comparison of success rates for that period is that Geopeko’s outstanding cost effectiveness was achieved in relation to nine new mines in quite different localities. Most other successful explorers had found only one mine in relation to their total expenditure.
The application of a better understanding of ore forming processes has obvious advantages in mineral exploration. The cost effectiveness demonstrated by the McKinsey report later resulted in the offer of research contracts to further test and develop the original findings and to introduce the new concepts to CRA-RTZ exploration staff. Because of the demonstrated potential economic advantage, the initial two-year contracts were exclusive and confidential. CRA was never opposed to eventual publication but sought to introduce the new principles to their own exploration teams first.
Page 2 as an extract from the report “Successful Management of Mineral Exploration in Australia” by McKinsey & Company, Inc. Management Consultants, New York, and dated 20th June 1975, is reproduced below: -