Key Highlights

  • The south-west Siguiri portfolio comprises eight near-contiguous projects covering 687 square kilometres.
  • Stream sediment anomalies and a soil sampling programme are guiding where drilling should go.
  • The earlier BLEG programme collected 202 drainage samples across all eight projects.
  • Anomalous gold values ranged from 6.62 to 56.20 parts per billion.

DeSoto Resources (ASX:DES) has updated the market on exploration across its south-west Siguiri portfolio in Guinea, a group of eight near-contiguous projects covering 687 square kilometres along the Siguiri gold trend. The update centres on stream sediment anomalies and a soil sampling programme designed to narrow down where drilling should eventually go.

Of a planned 2,239 soil sampling points, 1,105 have been completed, including 466 at the Yarakoura project. The company has also established a regional field office at Yarakoura to support logistics and access across the portfolio.

Following the stream sediments

DeSoto's earlier bulk leach extractable gold, or BLEG, programme collected 202 drainage samples, including 20 duplicates, across all eight projects. Anomalous gold values ranged from 6.62 to 56.20 parts per billion. The highest result, 56.2 ppb, came from Branama, with 18.3 ppb also at Branama and 13.9 ppb at Yarakoura. The Yarakoura, Woussoubadou and Branama areas were highlighted for more detailed work.

BLEG sampling is a cheap way to cover large areas by testing sediments in drainage channels for gold that can be leached out. A positive result points to a possible source upstream; it says nothing about grade or size. Soil grids are the next step, followed by auger sampling and, where warranted, drilling.

Soil grids of 200 by 200 metres are being used over higher-priority structural targets at Yarakoura, Branama and Woussoubadou, with wider 800 by 100 metre grids at Moiko and Alamakono.

Structural targeting

DeSoto has combined the geochemistry with airborne magnetic and radiometric data. Non-executive director Barry Murphy completed a structural interpretation identifying intersecting fault trends, contrasting magnetic domains and possible intrusive contacts that correlate with surface anomalies. The company describes this as a mineral systems approach championed by Murphy and chairman Paul Roberts.

The neighbourhood

Location is a big part of the Investment case. Yarakoura sits immediately south of Asara Resources' (ASX:AS1) 2.1-million-ounce Kada project, and DeSoto sees it as a priority area for testing whether favourable host rocks and structures extend south. DeSoto's western permits are about 40 kilometres east of Predictive Discovery's (ASX:PDI) Bankan deposit of 5.4 million ounces, which DeSoto says was originally discovered by Roberts in April 2020.

The trend also hosts AngloGold Ashanti's Siguiri mine. Asara has reported north-east to south-west structures crossing the main north-south corridor as an important control on higher-grade gold, and DeSoto plans to evaluate similar settings on its ground.

These neighbouring resources belong to other companies. DeSoto has no resource of its own, and a good address does not guarantee a discovery.

Why the funnel approach matters

For investors, the value of this kind of programme lies in its efficiency. Large land packages cannot be drilled systematically, so explorers use cheap, wide-spaced methods to eliminate most of the ground and concentrate spending on a few targets. The risk is that early anomalies fade on closer inspection, which is common in early-stage exploration programmes.

Auger drilling elsewhere

At Timbakouna, 596 of a planned 1,195 power auger holes have been completed, and more than 2,500 samples are at the laboratory. A wider 22,000-metre auger programme has also highlighted the Malikila prospect, a 1.5 by 1 kilometre gold anomaly that has never been drilled.

Since February 2025, DeSoto has acquired about 1,300 square kilometres of gold tenure across more than 23 reconnaissance authorisations and exploration permits in the Siguiri basin, and it is converting reconnaissance authorisations into exploration permits.

What to watch

No dates were given for the pending items: Timbakouna assays, completion of the auger and soil programmes, permit conversions and follow-up drilling. Investors should also keep in mind Guinea's evolving Mining policy environment, which can affect permitting timelines. The Timbakouna auger results are likely to be the first meaningful test of the company's targeting.