Welcome To Indomining | Indomining Welcome to PT Indomining, one of Indonesia''s lowest cost producers of thermal coal located in Sanga-Sanga, East Kalimantan. It is part of the Toba Sejahtra Group along with parent coal mining company Toba Bara . Corporate Social Responsibility. School Support & Scholarship. Nutrition for Kids. Regreening & Cassava Plantations.