South America focused oil and gas firm Amerisur Resources moved back into the black in the first nine months of its financial year.Operating profit in the nine months to the end of 2011 was $2.24m, versus a loss of $2.85m in the 12 months to 31 March 2010. The company is in the process of changing its year end to 31 December.Profit before tax was $2.3m in the latest nine month period, compared to a loss of $1.96m in the prior 12-month period. Revenue soared to $9.01m from $2.75m the year before as production ramped up at its Platanillo asset in Colombia.At the end of the 2010 the group had cash of US$20.7m (2009: US$8.0m), following the successful completion of a share placing to raise US$ 20.8m in April 2010.The company said it continues to generate positive monthly cash flow and during January 2011 hit a new monthly cash flow record from sales of $1.73m."Post period end we have modified our operational plan following the positive results of the interpretation of the 3D3C seismic survey over Platanillo and we expect to begin drilling before mid-year," company chairman Giles Clarke said.---jh