Reliance Industries Ltd (RIL) has begun talks with Coal India Ltd (CIL) to explore the possibility of striking a joint venture for a coal-liquefaction project. CIL sources confirmed that talks had already been held at the top level between the two companies. While RIL is stated to be interested in tapping underground coal mines for this project, CIL feels that this poses some issues like contamination of ground-water sources that would have to be sorted before venturing into the project CIL would be more interested in having such a project on the surface. Talks would progress after the technology issues were solved, it was learnt. CIL is keen on such a forward-integration project as it could get ammonium nitrate, an explosive it uses for its mining purposes and whose shortage is an area of concern. The project would entail a Rs. 2,400 -crore investment for setting up the plant and the two companies would form a joint working group to evaluate a detailed feasibility report.