Following successful ore sorting trials, St Barbara (ASX: SBM) is looking hard at the Cochrane Hill gold project in Nova Scotia. The company is evaluating an alternative design that would process the ore at the proposed 15-Mile mill.
The deposit has measured resources of 10.7 million tonnes grading 1.1 g/t gold (370,000 contained oz.), indicated resources of 7.7 million tonnes at 1.0 g/t gold (240,000 oz.), and inferred resources of 21.0 million tonnes at 1.0 g/t gold (690,000 oz.) Approximately half that tonnage is considered as proven an probable reserves: 15.4 million tonnes at 1.1 g/t gold (1.35 million oz.) (Resource and reserve numbers comply with JORC guidelines.)
The ore sorting trial was done on an 840-kg using x-ray transmission technology. The results recovered 89.7% of the gold from the bulk sample into a mass only 54.3% of the original sample, and the head grade was boosted 1.65 times in the concentrate.
With the ore sorting done, the idea of trucking it about 70 km by road to the site of the proposed 15-Mile mill makes economic sense. It makes more sense when
Other de-risking considerations for the Cochrane Hill project include better recoveries using the 15-Mile mill and no need to establish a tailings management facility at the mine. The pit design could be optimized to eliminate the need to relocate a public road. With no mill on site, water use would be considerably reduced, and the long-term waste rock storage could be altered to further reduce the project footprint and improve the landform design post-reclamation.
St Barbara’s Atlantic Gold division includes the now-closed Touquoy mine, development of the 15-Mile underground mine mill, the Beaver Dam open pit project, and the Cochrane Hill open pit deposit. The mill from the Touquoy carbon-in-leach (CIL) mill can be relocated to the 15-Mile mine and its capacity increased to 2.1 million t/y of processing capacity.
Meanwhile, St Barbara is working on a feasibility study for a pumped hydro energy storage facility at the closed Touquoy mine. Capacity has been upgraded to 80 MW of power available to the grid for seven hours. Collaboration continues with Natural Forces Solar. The partners also plan to evaluation the potential for similar pumped hydro energy storage at the 15-Mile and Cochrane Hill projects.
Learn more on the company’s website, www.StBarbara.com.au.
