(ShareCast News) - Stellar Diamonds has more than doubled its full-year pre-tax loss due to a significant rise in the impairment of intangibles, and says it is pursuing a transformational acquisition."At the same time maintain exposure to our quality portfolio of diamond assets in West Africa," said chief executive Karl Smithson in a statement.Pre-tax loss was $7.1m, from $3.09m. It booked $4.3m for the impairment of intangibles, from $605,728 a year earlier."During the past year we have pursued the key strategy of consolidating our Tongo kimberlite dyke licence with the adjacent Tonguma kimberlite dyke mining licence in order to create an enlarged hard rock mining operation that can offer long-term and sustainable production and revenues," said Smithson."In the event of completion of the acquisition of Tonguma, the combined mine would have an initial inferred +1.18mm diamond resource of 4.5 million carats, with diamond values ranging from US$209/ct to US$310/ct, from just three (of eight) kimberlite dykes in the licence areas, all of high grade and high diamond values."Smithson added that the PEA demonstrated a life of mine of 20 years with production estimated to be over 200,000 carats per year for the most part."The acquisition process is ongoing and remains the focus of Stellar (albeit there is no guarantee that it will be completed). In order to focus on the acquisition we undertook to joint venture our Baoulé kimberlite pipe project in Guinea and our Liberian licences to Citigate whilst retaining a free-carried interest in these projects."The earn-in allows for Citigate to fully fund both projects but Stellar's existing teams on the ground will manage the projects for the first phase of work and will also receive a management fee for doing so."At about 11:12 GMT, shares in AIM-quoted Stellar were flat at 7.12p.