In addition to the regional BRGM soil surveys, Anglogold Ashanti (Ashanti) also conducted a soil geochemistry survey across the area. This consisted of a total of 2,040 samples along lines oriented N130°, with a detection limit of 5 ppb gold. Four percent of the samples returned Au values greater than 100 ppb. Some of the anomalies were partially followed up with a limited program that included a total of sixteen trenches and associated rock chip sampling. This latter sampling involved the collection of 192 samples and returned a maximum gold concentration of 15 g/t. There has been no commercial gold production from the area. However, disused artisanal workings are present within the property boundaries. In the northeastern corner of the licence area, a wide zone of artisanal pits were observed, round in dimension, around 1 metre in diameter and up to several metres deep that appeared to follow a northeast-southwest trend. Abundant vein quartz was present in the vicinity of the pits, which appeared to have been disused for a few years.
The Samaya licence area is located within the Bougouni region of the West African craton, where generally north-south trending belts of Birimian metavolcano-sedimentary and metasedimentary rocks and orogenic granitoids of Early Proterozoic age crop out. The trend of the major structures is northsouth and northeast-southwest, which are related to transcurrent D2 and D3 deformations. The Samaya licence area is located within a large northsouth trending belt of Birimian volcano-sedimentary formations, composed of metagreywackes, metapelites and volcanics including felsic tuffs. The greywackes are schistose with pervasive carbonate alteration, and are often intercalated with phyllites. The felsic tuffs are relatively massive and contain Au-bearing quartz stockworks. A major northsouth trending fault runs through the centre of the property, which has juxtaposed largely felsic volcano-sedimentary units to the east against largely basic units to the west. Some narrow bodies of mafic and intermediate igneous rocks of similar age are also present in the northern part of the licence area. Other than some outcrops of felsic tuff, the rest of the area lacks outcrop, with a thick lateritic weathering profile present. The only lithology type present at the surface in most places is pisolitic laterite. Abundant quartz float within the licence area was observed, together with a number of nodules of fine-grained mafic volcanics in the northeastern part of the property which is consistent with the mapping of linear bodies of such rock in the area.
In addition to the regional soil survey by the BRGM, Ashanti undertook a more detailed soil survey. Ashanti also completed a program of pitting, trenching and rock chip sampling which involved 16 trenches totalling 1259 m³ and 24 pits of 3 metres depth totalling 72 m³ within the zones of anomalous soils. Three-hundred and thirty-six composite samples were collected and analysed at ABILAB in Bamako. One-hundred and ninety rock chip samples from bedrock and quartz veins were also analysed at the same laboratory. The results of the rock chip samples returned 12 samples with Au grades of between 1 and 8 g/t with a single sample at 15 g/t gold. The samples from the trenches (2 metres composite samples) returned poor gold grades, with only two samples from 300 containing gold grades greater than 1 g/t. The total exploration budget spent by Ashanti during these works was CFA49,790,113.
The property is bordered on its eastern edge by African Gold Group (AGG) Research Permit Kobada, and at the south by the Medoro's Niaouleni West licence area. The northwestern side of the property borders the Niger River. AGG has completed an extensive exploration program on the adjacent Kobada property to the east with both diamond and RC drilling. Drilling to date has reached depths of 125 vertical metres without completely penetrating the saprolite horizon or intersecting bedrock. It is possible that these northeast-southwest trending veins continue into the southeastern part of the Samaya licence area.
The Samaya licence area is located on a northsouth trending belt of Birimian metasediments and volcanics and includes a major contact between largely felsic tuffs to the east and mafic volcanics to the west that runs down the centre of the licence. The geochemical soil sampling indicates a series of strong Au anomalies in the eastern part of the property (where felsic tuffs predominate) that correspond with high potassium anomalies and appear to show a number of northeast-southwest trending linear anomalies. The linear anomalies are most likely to be related to northeast-southwest fault systems and be an extension of the similarly trending quartz vein structures in the adjacent Kobada property to the east. The size of the anomalies, plus the grades available for the Kobada quartz veins (consistently thick 20-90 metres intersections at over 1 g/t gold), together with the known presence of vein quartz in the artisanal workings on the property would suggest a high potential in the eastern part of the Samaya prospect area for mesothermal gold-bearing quartz veins. Rock chip sampling by Ashanti revealed a number of well mineralised samples with gold grades in the region of 1-8 g/t in around 7% of samples. Primary targets in the Samaya area occur in the eastern part of the licence, where the soil anomalies are the highest and where the potassium anomalies indicate northeast-southwest trending structures that extend into the adjacent licence to the east. Access to the area is reasonable, along gravel roads from the Selingué dam in decent condition. The River Niger, which forms the northwestern margin of the licence and provides an obvious source of water.
The Samaya licence area shows good potential for mesothermal gold-bearing quartz vein type mineralisation for the following reasons:
- Consistently high gold soil anomalies within the eastern part of the licence;
- The extension of geological structures containing known auriferous quartz veins into the property from the east;
- The presence of gold mineralisation as identified by the limited previous exploration works; and
- Vein quartz in artisanal pits.