Suitability Of Conventional Oxide Processing Methods At Atlanta Confirmed

Suitability Of Conventional Oxide Processing Methods At Atlanta Confirmed

VANCOUVER – Nevada King Gold Corp. reported on the Phase I metallurgical testing program at the Atlanta Gold Mine Project, located in the prolific Battle Mountain Trend, 264km northeast of Las Vegas, Nevada. The objective of the Phase I program was to test the various mineralized host rocks at Atlanta for gold and silver extraction, using conventional flowsheet unit operations to guide in selecting a process flowsheet suitable for the commercial extraction of gold and silver from the project. Results of the Phase I test work support strong recoveries utilizing conventional Nevada oxide processing methods for the representative mineralization types present at Atlanta.

Phase I testing used three surface bulk samples and 19 composites from drill core comprising the full range of rock types and gold and silver grades encountered across Atlanta. Mineralization at Atlanta can be broadly characterized by two major host domains: 1) Silicified breccias found within and below the main Atlanta unconformity, and 2) Volcanics found above the main Atlanta unconformity. Results of Phase I support conventional Nevada oxide processing methods for Atlanta whereby: 1) Silicified breccias are amenable to conventional milling for high-grade material and High-Pressure Grinding Roll (“HPGR”) crushing and heap leaching for the lower-grade material. 2) Volcanics are amenable to conventional milling for high-grade material and Conventional Crush or Run-of-Mine (ROM) heap leaching for the lower-grade material. 3) Applicable to process plant scenarios, gold extraction from fine milling at a 200-mesh grind (P80=75µm) show a weighted average extraction of 91.7% for gold hosted in volcanics and 85.9% for the high-grade silica breccias. 4) Silver extraction from fine milling at a 200-mesh grind (P80=75µm) show a weighted average 65.3% in the volcanics and 41.3% in the silica breccias. At coarser crush size silver extractions are similar between the two metallurgical domains. 5) Applicable to heap leach scenarios, gold extraction from conventional crushing (P80=12.5 mm) shows a weighted average extraction of 87.1% for gold hosted in volcanics. Gold extraction from HPGR crushed composites (using medium press force) shows a weighted average 71.4% extraction from low-grade silica breccias. 6) A Phase 2 metallurgical PQ core drilling program has now been completed to fill some gaps in the target resource envelope and further laboratory testing utilizing material from this drilling is scheduled to start later in 2024.

Gary Simmons (MMSA QP Number: 01013QP), said, “Historic production at Atlanta focused on near-surface high-grade silica breccia ores that were processed and recovered using conventional oxide milling practices. Historical records (1979-85) indicate recoveries from the silica breccias necessitated a fine-grind milling and Merrill-Crowe recovery process that averaged 81% for gold and 42% for silver at ball mill grind P80 = 120µm (microns). This historical milling operation was challenged by the hard and abrasive nature of the silica breccias, resulting in elevated-maintenance and operating costs in primary, secondary, and tertiary crushing circuits. The results confirm that conventional oxide milling, and HPGR crush heap-leach or ROM heap-leach, depending on mineralization type, are well suited for processing gold and silver mineralization at Atlanta. Referring to a conceptual Atlanta generalized flowsheet a straightforward process breaks out the host mineralization into their respective silica breccia and volcanic units, running high-grade mineralization through a mill and processing lower grade material via a combination HPGR crush and ROM heap leaching. The adoption of HPGR crushing technology (used at other mines in Nevada and around the world) will eliminate SAG milling of silica breccias and high-grade volcanics that in turn should result in reduced overall operating cost against a conventional SABC (Semi-Autogenous-Ball Mill-Crusher) circuit design. It is anticipated that this process will be more cost-effective than historical methods, resulting in lower process cutoff grades and potential for economic extraction of gold and silver from a larger volume of material.”

Collin Kettell, Founder & CEO, said, “Positive results from the Phase 1 metallurgical test work released today indicate a clear path forward for processing Atlanta’s gold and silver mineralization via a combination of crushed and run-of-mine heap leaching together with conventional milling of high-grade mineralization. In a major departure from historical processing and test-work at Atlanta, the potential for using HPGR crushing, as indicated by Phase 1 enhanced test recoveries, could result in very significant benefits and opportunities for flow sheet development in a future potential mining operation. Test results also indicate significantly higher Au/Ag recoveries in the volcanic section, which is fast becoming a major component of the overall mineralized footprint at Atlanta. Looking forward, ongoing resource modeling and metallurgical studies will focus on optimizing the potential economics of mining and processing scenarios utilizing the alternative process options for which this Phase 1 testing program has indicated positive extraction results.”