As part of the contract extension, which begins next month, Capital Drilling will use the existing underground drill fleet already located on site.
The underground drilling work represents a subcontract of the comprehensive drilling services contract at Geita, which encompasses blasthole, grade-control, delineation, exploration and underground drilling.
The master contract is for a period of five years, running to December 2020. Capital Drilling originally commenced drilling operations at the Geita mine in 2006.
Commenting on the contract extension, Jamie Boyton, executive chairman said: "The experience Capital Drilling has gained at the Geita gold mine over the past 13 years underpins our strategy of targeting Tier 1 long-life assets with quality operators."