The gold mine has its own power plant to provide electricity for the operations.
Wärtsilä has run and maintained the plant since 2009. The company said it had enabled PGPRC to consistently meet its production targets through high plant availability.
The extension to the agreement was placed with Wärtsilä in June 2019.
Erwin Vanderkerff, director for the service unit Australasia, Wärtsilä Energy Business, said the adjusted O&M agreement comes at set cost and technical support would always be available.
"In this we utilise Wärtsilä Expertise Centre for providing remote operational support and extensive technical support," he added.
"The customer's evolving requirements have been answered to by the further customised scope of the agreement. Performance guarantees covering heat rate and annual availability of the power plant have been defined."
No financial details of the deal were disclosed.
The remotely located plant operates on three 18-cylinder, two 16-cylinder Wärtsilä Vasa 32 engines and one 12-cylinder Wärtsilä 32 engine, and has a total power output of 36.93MW. The plant is located approximately 360km southeast of the country's capital. There is no connection to the grid, and the island-mode plant is the sole provider of energy to the mine.
In the Philippines, Wärtsilä has altogether 2,000MW of installed power capacity, of which 110MW is operated and maintained by Wärtsilä under O&M agreements.
B2Gold acquired an interest in the Masbate mine through its acquisition of CGA Mining in January 2013. The company has indirect ownership of Philippine Gold, which owns 40% of Filminera Resources Corporation, the owner of the Masbate project. Zoom Mineral Holdings, in turn, owns the remaining 60% of Filminera.