According to its 30.4% shareholder Stratex International (AIM:STI), Thani Stratex asked for a hold on its Blackrock and Cussra licences instead of a proper renewal, which was not possible under the Ethiopian mining code.
Stratex handed the company $200,000 at the end of 2017 to keep working on its Egypt and Djibouti prospects.
The Ethiopia prospects were not mentioned in Thani Stratex's most recent corporate presentation, and no detail was given on how the US$8.7 million valuation was reached.
Stratex CEO Tim Livesey, whose company will book a $2.7 million loss from the cancellation, said the write-down was a shame but strategically the holdings were no great shakes.
"We understand that TSR had applied for a sabbatical at the licences until 2019 so that it could concentrate on its core projects in Djibouti and Egypt," he said.
"However, they have since received notification that this would be outside the scope of the mining legislation and the licences have subsequently been cancelled.
"Whilst this cancellation and the related write-down is disappointing, the projects in Ethiopia have been non-core for TSR since it formed in 2014 and its focus continues to be on its projects in Djibouti and Egypt."
The Thani part of the name comes from 47% shareholder Thani Emirates Resources.