Arizona Gold and Silver reports up to 99% gold recovery at Philadelphia project
Arizona Gold and Silver CEO Mike Stark joined Steve Darling from Proactive to discuss encouraging metallurgical test results from the Philadelphia gold-silver project in Mohave County, Arizona, highlighting strong gold recoveries through both agitation and heap leach processing.
Stark said agitation leach cyanidation achieved gold recoveries of 91% to 99% using modest grind sizes of 0.40 to 0.136 mm (40–110 mesh). More than 50% of the total gold was recovered within the first 10 days of column leaching, demonstrating rapid extraction characteristics.
Heap leach testing also delivered positive results, with 84% gold recovery from bulk material crushed to -6.3 mm using high-pressure grinding rolls (HPGR) over a 177-day leach cycle. Regression analysis indicates recoveries could increase to approximately 86% over 360 days.
Silver recoveries ranged from 49% to 72% through agitation leaching, while heap leach processing achieved 37% silver recovery. Testing also showed that HPGR crushing improved gold recovery by 12% compared with conventional crushing methods, while silver recovery improved by approximately 3%.
Agglomeration and compaction testing demonstrated that the crushed material is suitable for heap stacking heights of 10 to more than 30 metres with the addition of only 2 to 4 kilograms of cement per tonne, supporting the project’s heap leach potential.
Based on the results, management believes higher-grade material could be processed through agitation cyanide leaching to maximize gold and silver recovery, while lower-grade ore could be treated economically through HPGR-assisted heap leaching.
The metallurgical work was conducted on a 415.5-kilogram bulk sample collected from the current surface operation. Head assays returned 1.929 to 1.988 g/t gold and 2.82 to 3.34 g/t silver, exceeding the original target grade of 1.0 to 1.2 g/t gold. The company said the higher grades are consistent with previous sampling, reflecting the presence of fine and wire gold within the deposit.
Courtesy of Arizona Gold, and Silver via Proactive Investor
