(ShareCast News) - Africa focused oil and gas exploration group Bowleven posted its preliminary results for the year to 30 June on Tuesday, in another year of nil revenue, though operating expenses were lower at $9.1m compared with $11.87m a year earlier.The AIM-traded company reported an operating loss before financing costs of $143.21m, almost double the $87.83m in 2015.That was due to a much larger impairment charge at $122.31m, compared to $75.96m, with unsuccessful exploration costs of $11.82m, compared to nil last year.Bowleven's loss for the year for continuing operations of $129.27m, wider than the $90.02m in 2015.Basic and diluted losses per share from continuing operations were 39 cents, compared to 28 cents."We have continued to make steady progress towards our objective of converting resources to reserves in Cameroon, despite the challenging macro environment," said chief executive Kevin Hart."The Etinde operator, NewAge, has prioritised advancing development plans with the government over planned appraisal drilling activity."Hart said Bowleven remains eager to drill the two wells as soon as practicable, being covered for its share of drilling/testing via the $40m net carry from the Etinde farm-out transaction."On Bomono, discussions are ongoing with the Cameroon authorities for a PEA to enable the progression of development activities."The macroeconomic environment of prolonged lower oil prices has had sector-wide repercussions," he said."The group's strong balance sheet including $100m in cash and no debt or outstanding work programme commitments means it is well positioned to manage the challenges faced by the industry and to exploit opportunities as they arise."Hart said the board has extensively screened multiple opportunities and the search is continuing. "This is a time-consuming exercise that demands proper rigour be applied to the evaluation of any potential transaction to ensure value is created for shareholders whilst protecting our key differentiating feature of balance sheet strength."Bowleven remains optimistic that portfolio-enhancing transactions will be identified and delivered alongside the progression of our existing asset base and we look forward to making further progress in the coming year."