Arizona Gold & Silver Inc (TSX-V:AZS) has begun crucial column leach test work on its Philadelphia gold-silver property in Mohave County, Arizona.
The move is a significant step in assessing the potential for low-cost heap leaching of the stockwork mineralized zone and understanding silver extraction.
Arizona’s vice president exploration Greg Hahn told shareholders that column leach tests are necessary to assess the potential for low-cost heap leaching of the stockwork mineralized zone and to address the extraction of silver.
The company is utilizing two bulk samples from underground workings and a surface mining bench for the column leach tests, according to a statement.
The program will also assess load permeability tests to determine potential heap heights under different crush size scenarios.
Previous tests in the 1980s by Mountain States R&D Labs in Tucson demonstrated promising gold extractions after a 19-day leach cycle for similar crush sizes, with recoveries ranging from 58.5% to 91%, according to the company. However, this earlier data lacked silver extraction information.
The current program aims to fill this gap by extending the leach cycle to 90-120 days for each column, simulating actual heap leach conditions.
“Extrapolating the leach curves from the Mountain States R&D test work to 90 days suggests we should expect ultimate extractions of 70% to 90% for our test work,” Hahn said.
The company plans additional column and agitation leach tests in 2024 on dedicated drill core samples, providing a comprehensive understanding of leach characteristics and kinetics across the entire deposit's strike length. These tests will cover both high-grade veins and stockwork mineralized zones.