The Mato Bula and Da Tambuk mining licenses, collectively referred to as the Adyabo Project, are held by Tigray Resources Incorporated PLC (“TRI”), which is owned by Tibet Huayu and East Africa, 70% and 30% respectively.
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Summary:
The Mato Bula gold-rich VMS deposit is the main deposit discovered to date within the Adyabo Project, and covers the Mato Bula North, Silica Hill North, Silica Hill, Mato Bula, Jasper Hill and Halima Hill mineralized zones.
Two mineralized structures are present at Mato Bula Hill; the Main lode and the Upper lode.
The Main lode at Mato Bula is located south of the crest of the Mato Bula Hill, and is a narrow high-grade gold shoot extending over a strike length of 120 m at surface. Numerous active artisanal gold bedrock workings are present at Mato Bula exploiting this gold lode, and an upper lode, reportedly to a depth of 46 m.
The shoot has steep dip, vertical plunge, and maximum true width of 3 m. At depth the maximum strike of the shoot is reduced to 80 m, but the structure remains open at depths greater 220 m below surface.
Silica-pyrite alteration is extensive laterally (750 m strike) and in thickness (159 m wide), and zones of silica-pyrite are present in the hanging wall and along strike, in a zone up to 150 m wide and 750 m long.
Mineralization is hosted within a shear zone that contains abundant quartz veining, silicification, sericitization and carbonate alteration. Gold is associated with chalcopyrite-rich veins in intense silica alteration, and also the presence of possibly V-rich mica (roscoelite). The Main lode averages 5.5 g/t gold and 0.61% copper, and has a high gold:silver ratio of 10.2. Lead and zinc concentrations are negligible.
The Jasper Hill zone (sometimes known as Mato Bula South) contains structurally controlled gold lodes (vein/wall rock porphyry hosted), and extend from the Mato Bula zone in the north towards Halima Hill in the south. The upper and main lodes within this zone exhibit more complex geometry due to possible faulting (or slumping) and wall rock interaction. Mineralization is lithologically controlled with the gold-bearing zones within a jasperoid alteration zone. Gold concentration decreases, with increasing zinc concentration, moving away from the jasperoid unit. Gold-bearing veins have also been identified perpendicular to the long core axis.
The Main lode at Jasper Hill is located 40 m southeast of the Upper lode, southwestwards along strike from the Mato Bula zone, and outcrops along strike for 80 m. The structure has a maximum true thickness of 9 m, and an average gold grade of 4.53 g/t and copper grade of 0.85%. It has the highest gold:silver ratio in the Mato Bula prospect of 5.3:1, and a low gold:copper (x10) ratio of 0.56:1. The average silver concentration is low, 0.85 g/t, and only trace amounts of lead and zinc are present. The lode plunges at approximately 60 to 70° to the southwest, and remains open down plunge below depths of 200 m from surface.
The most southerly manifestation of the Mato Bula Trend is the mineralized zone at Halima Hill, 320 m to the southwest of the Jasper Hill zone. Halima Hill was targeted due to the presence of artisanal trenching, with lower order gold-copper geochemistry present within an alteration zone. Apart from a zone of subcrop at Halima Hill, much of the southern part of the trend is covered in thick (50 cm to 2 m) transported colluvium, thus reducing the geochemical signature at Halima Hill relative to the hilltop workings of Mato Bula North, Silica Hill and Mato Bula.
Mineralization was present as pyrite- chalcopyrite bearing quartzveins within altered tuffs. The assay results and visual interpretation of alteration at Halima Hill indicate the Mato Bula system is weakening to the south near surface, however the IP survey is suggestive of additional increasing potential at depth.