Coal Fly Ash as an Alternative Energy Efficient Building Material for Cement

The 10 largest coal producers and exporters in Indonesia:

1. Bumi Resouces
2. Adaro Energy
3. Indo Tambangraya Megah
4. Berau Coal
5. Bukit Asam
6. Baramulti Sukses Sarana
7. Harum Energy
8. Mitrabara Adiperdana 
9. Samindo Resources
10. United Tractors