Large Tonnage, Low Stripping, High Recoveries
As with any highly credentialed locality, when moving into Western Australia’s Eastern Goldfields an exploration company needs to demonstrate that it can fit in with its well-heeled neighbours.
Since arriving in the Eastern Goldfields in 2018, Saturn Metals (ASX: STN) has unlocked the potential of its 100 per cent owned Apollo Hill gold project, to the point where it could be the project that other companies covet.
The region between Kalgoorlie and Leonora is a well-documented piece of gold real estate, with a number of multimillion-ounce gold deposits already operating, being worked up, or being considered in merger and acquisition activity throughout the district.
Saturn Metals’ Apollo Hill Project comprises 31 highly prospective gold exploration and prospecting licences, covering approximately 1600 square kilometres of ground, including two mining leases.
The project’s major asset is the Apollo Hill 2018 JORC Code–compliant Indicated and Inferred Mineral Resource of 76 million tonnes at 0.6 grams per tonne gold, for 1.469 million ounces above a cut-off grade of 0.23 grams per tonne gold.
Although the size of the resources is important, what is probably more important to note is the style of the deposit, the ore it sits in, and how the gold can be recovered.
Basically, Apollo Hill is emerging as a very large-tonnage, low-strip pit that is approaching the dimensions of a super pit from a width and length perspective.
‘This is not a small project,’ Saturn Metals Managing Director Ian Bamborough says.
‘We have continued to add ounces in the southern part of the deposit and have also taken the pit concept deeper, to around 250 metres.
‘There are a number of key reasons it works as a simple, efficient operation using clean metallurgy,’ he says.
Saturn Metals has carried out comprehensive metallurgical test work to assess the potential for a bulk-tonnage gold mining operation at Apollo Hill.
From this, the company has achieved excellent recovery results, highlighting the deposit’s amenability to simple low-cost mineral processing methods, including heap leaching, which can drive lower stripping ratios and efficient mining processes.
Heap leach processing is used by many large-scale gold mining operations, accounting for approximately 46 per cent of global gold production.
The reported global average grade of heap leach operations is 0.7 grams per tonne and, on average, 65 per cent of gold is recovered.
Saturn Metals believes it has demonstrated that Apollo Hill has the potential to join this cohort.
By targeting a lower unit operating cost, Saturn Metals plans to utilise lower cut-off grades, thus allowing for the processing of additional mineralised material for improved strip ratios, as well as more efficient mining processes and economies of scale.