JOHANNESBURG (miningweekly.com) – A reconnaissance fieldwork programme by Sula Iron & Gold to determine whether coltan was being produced by artisanal miners on the exploration licence at its Ferensola project, in Northern Sierra Leone, has provided an initial indication of prospective areas of mineralisation.

The iron-ore, gold and coltan producer said on Friday that some samples, which were obtained from alluvial gravels at 46 locations, screened with a 2 mm sieve and fraction-panned to a heavy mineral concentrate, showed elevated concentrations of tantalum.

“One sample in the south-east quadrant of the licence area grades at more than 3% tantalum and provides strong evidence for the presence of coltan mineralisation in the vicinity. 

“Other high-grade samples are found near the eastern boundary of the licence but are found along streams that flow from deeper within the licence area, suggesting that further alluvial and primary coltan mineralisation may be found in this part of the licence,” the group said in an update.

Owing to the nature of pan concentrate sampling, it cautioned, however, that the results were indicative and did not provide values for in-situ grade.

“The results of this reconnaissance work, while only indicative, provide useful guidance as to the main prospective areas within the exploration licence and provide further support to this area's potential to host deposits of coltan mineralisation,” Sula outlined.

The results would be used to guide the ongoing pitting programme for coltan, which would provide more quantitative data. 

CEO Nick Warrell said Sula was “excited” by the confirmation that there was coltan mineralisation along the streams that flowed deeper within the licence area, further proving the high prospectivity of the area.

“This is also positive news as we progress our talks with a potential offtaker for the project,” he stated.