Allegiant Gold Ltd. (TSXV: AUAU) (OTCQX: AUXXF) announced the discovery of high grade gold at its Castle Project in the Eastside District in Nevada on Wednesday.
Allegiant drilled six core holes totalling 1,200 meters at its Castle Project, including the Boss Mine on the Eastside Property. It drilled three holes at the Boss Mine deposit and another three at the northern end of the Castle deposit.
Assay results from the drilling confirmed significant additional resource potential at the north end of the Castle deposit. Previously published resource estimates identified an area in the north of Castle where the planned open-pit mine splits into two separate pits.
The drilling program completed in late March 2024 confirmed the presence of oxidized gold-silver mineralization between the two pits. Combining these two smaller pits into one larger pit could significantly increase the overall resources at the Castle Project.
Highlights from the drilling program include:
- High-grade gold values up to 5.04 g/t Au from drill hole ES-315 and 204.0 g/t Ag in drill hole ES-312
- Broad zones of low-grade gold silver mineralization in the Boss and Castle deposits including 24 meters at 0.51 g/t Au and 1.33 g/t Ag as well as 29.6 meters of 0.39 g/t Au and 2.85 g/t Ag from drill hole ES-315
- Quartz veins occur within intensely altered and oxidized host volcanic rocks
- Boss mine dumps containing gold and silver values up to 0.44 g/t Au 10.4 g/t Ag
The core drilling program also identified high-grade gold mineralization exceeding the average grade of 0.49 g/t gold reported in the Castle deposit’s inferred resource technical report.
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📣 HEY, STOP ON!
We are pleased to report that the recent diamond core drilling program at The Castle Project within Eastside has yielded positive results 🏗 pic.twitter.com/bp3wwQRUvv
— Allegiant Gold (@allegiantgold) May 22, 2024
Core drilling at Castle Project found new information
Assay results revealed gold values as high as 5.04 g/t Au. This high-grade zone was found within a mineralized interval of fully oxidized tertiary volcanic rocks containing epithermal quartz veins.
The interval averaged 0.51 g/t gold and 1.33 g/t silver over 79 feet (24 meters) at a depth of 311 feet (94 meters). To include this mineralization in the resource estimate and potentially upgrade the resource category from inferred to indicated, Allegiant will need to conduct further drilling in the northern portion of the Castle deposit.
The core drilling program at Castle Project yielded significant new information about the types of gold and silver mineralization present. One key finding is the presence of massive grey quartz veins and veinlets. These veins run nearly vertical and are hosted within altered volcanic rocks. Importantly, these veins typically contain gold grades exceeding half a gram per tonne, making them potentially economically viable.
Another important discovery is the existence of disseminated mineralization zones. These zones are characterized by lower gold grades, typically less than half a gram per tonne. However, they are widespread throughout the deposit area. Unlike the quartz veins, these zones consist of iron-oxide filled fractures within altered volcanic rocks and often lack visible quartz veins.
The analysis of the core samples also revealed widespread silver throughout the project area. This silver is present not only in the volcanic rocks, but also in the underlying sedimentary rocks. This finding suggests that both rock types were extensively altered by hydrothermal fluids. The presence of silver across such a large area strengthens the theory that a very large hydrothermal system played a role in depositing both the gold and silver mineralization at Castle Project.
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Heap leaching is cost-effective for metal extraction
Allegiant is actively exploring five promising gold projects all situated in Nevada. The Eastside project is its crown jewel. It’s a massive gold resource with ongoing expansion. This project is conveniently located near excellent infrastructure, and initial tests suggest that both oxide and sulfide gold present there are suitable for heap leaching, a cost-effective extraction method.
Heap leaching is a cost-effective way to extract metals, especially gold, from lower-grade ores. Crushed ore sits on a lined pad and gets doused with a solution that dissolves the target metals. This “pregnant solution” drips down and is collected, while the metals are later separated out through additional processes.
Besides Allegiant, several other companies are utilizing heap leaching to extract gold from Nevada’s rich deposits.
One such company is Calibre Mining Corp (TSX: CXB) (OTCQX: CXBMF), which operates the Pan Mine in east-central Nevada. This open-pit, Carlin-style mine leverages heap leaching to process its gold ore. Calibre has seen continual production increases since restarting operations in 2017, with ongoing exploration efforts aiming to further expand the resource potential of the Pan Mine.
Another Nevada-based company employing heap leaching for gold recovery is the Barrick Gold (TSX: ABX) (NYSE: GOLD) owned Cortez Hills mine complex in Eureka County. This large-scale operation utilizes heap leaching alongside other processing methods to extract gold from its complex ore types.
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