Perth-based silver developer Sun Silver (ASX: SS1) has reported fresh cyanide leach results from its Maverick Silver Project in Nevada, with silver recoveries of up to 87.7% and gold recoveries of up to 87.5% in bottle-roll tests released on 14 October. The numbers matter because processing performance is one of the biggest swing factors in whether a silver-gold deposit can move from resource to a bankable study.
What the testwork showed
The tests were run by Independent Metallurgical Operations, a subsidiary of SGS, on oxide and transitional material taken from 242 half-core intervals, split into two composites. At a fine grind of 53 microns, one test returned 84.5% silver and 83.6% gold, while another reached 87.7% silver and 87.5% gold using lead nitrate. Most of the recoverable metal came out within 24 hours, which points to fast leach kinetics. Lead nitrate sped up early silver extraction, though its benefit had largely faded by 48 hours at higher cyanide dosing. A coarser 106 micron grind delivered 83.9% silver, a useful sign for grinding energy costs.
Where the project goes next
Sun Silver is now weighing tank leach or carbon-in-leach against heap leach, noting that a tank flowsheet could give more flexibility for future antimony recovery. Earlier results released in March showed heap leach style recoveries of around 77%, so the latest data lifts the upper end of the range. Next steps include optimising reagent use, testing coarser grinds, column leach work, a maiden antimony resource estimate and continued engagement with US agencies on possible project support. The company has not selected a processing pathway, and the interim 24 and 48 hour figures are indicative only.
What it means for ASX silver investors
Strong metallurgy lowers technical risk, but it is not a funding solution. Maverick remains an early stage project, and developers across the sector are competing for capital, as seen in the latest silver supply and demand picture and in other explorers such as West Coast Silver. Investors can weigh results like this against longer term demand data from The Silver Institute, and should note that recoveries from bottle-roll tests can differ from commercial plant performance.
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