A former environment and energy minister for Costa Rica has filed suit against Rapid City-based Black Hills Corp., alleging he was deprived of millions of dollars of royalty payments.

Roberto Dobles alleges he had a deal with Black Hills to shepherd the approval process that would allow the company to pump as much as a billion barrels of oil in a 2.3 million-acre region in the northern part of the country. But the deal ultimately withered because Black Hills failed to act and then chose not to renew its bond securing the hydrocarbon concessions.

Besides serving as minister of environment and energy, Dobles also served as president and CEO of Costa Rica’s national electric utility and president and CEO of the Costa Rican national oil company.