They have been extensively altered by hydrothermal circulation, but may be derived from intrusive alkaline rocks emplaced about 750 Ma along what is today the Albertine Rift.

The Neoproterozoic sediments contain small granitic intrusions from which colonial companies and artisanal miners extracted tin.

The main ore deposit is a zone up to 200 metres (660 ft) wide of mudstone, siltstone and porphyry sills containing an irregular network of sulphidic veins.

[6] In 1976 MGL merged with eight other mining companies to form the Société Minière et Industrielle du Kivu (SOMINKI).

[2] Banro Resource Corporation of Canada acquired control of the property in 1996, and between 1997 and 1998 undertook extensive explorations, including geological mapping, airborne geophysical surveying and diamond drilling.

In early 2018 a Canadian court allowed the Banro's main creditors to become its senior shareholders as part of a rescue plan.

These were Baiyin International Investment,[b] controlled by the Chinese government, and Gramercy Funds Management of Connecticut, USA.