During 1996 and 1997, Sipa Resources Limited (ASX:SRI) (“Sipa”) discovered four deposits at Ashburton – Mt Olympus (including West Olympus), Zeus, Peake, and Waugh.
Together these four open pits produced approximately 350,000oz of gold from 3.2Mt of oxide (and minor transition) ore at an average grade of 3.3g/t Au between December 1998 and April 2004 (Figure 2). The majority of the gold came from Mt Olympus which produced 242,000oz of gold from 2.5Mt at an average grade of 3g/t Au, with a recovery of 92% and a strip ratio of 3:1.
The onsite plant was sold in 2006 and site rehabilitation was completed in 2007.
Sipa and Newcrest Limited (ASX:NCM) entered into Farm-in and Joint Venture Agreements in June 1998 covering all Sipa’s tenements, except the Mount Olympus, Zeus, Peake, and Waugh deposits. Newcrest withdrew from the project in May 2009 after spending more than $20 million, with estimates that 60% of this expenditure was spent on field activities.
Northern Star acquired the Ashburton Gold Project from Sipa in February 2011 and went on to complete exploration and drill programs in 2012 and 2013.
In 2013 Northern Star released an updated Mineral Resource estimate which expanded the Mineral Resource JORC Code (2012) to 20.79Mt @ 2.45g/t for 1.65M oz Au