Of the twelve coal blocks explored so far, only six would be put up for auction due to various reasons, according to sources.

"In total 12 coal mines are explored, but we would be able to put up for auction only six blocks. We would not be able to auction other six explored mines for reasons like some of them being Coal Bed Methane blocks, among others," a source in the Coal Ministry said.

Of the 54 coal mines identified to be allocated through auction and government dispensation route, only 12 have been explored so far, Coal Secretary S K Srivastava had earlier said.

The government kick-started the process of allotting coal mines last month and invited proposals from PSUs for allotting 17 blocks to them, mostly for captive power plants.

The development came in the wake of the government's repeated announcements to make policy for mines allotment transparent, following CAG terming potential losses of Rs 1.86 lakh crore to the exchequer on account of blocks allotment to 57 private firms without auction.

Srivastava, had earlier, refused to give a timeframe for conducting auction of these blocks and stated that there were issues which have long-term implications and needs more and more consultations.

The government had advised Crisil to further consult ministries, including Ministry of Environment and Forests (MoEF).

"We told them (Crisil) to go and consult Planning Commission with regard to pricing issue. We have also told them to consult MoEF whether in-principle clearances are possible or not," he said.

MoEF, however, conveyed it to the Coal Ministry that in-principle environment and forest clearances for coal mines was not possible.

Crisil had in October submitted a draft report on methodology for fixing floor and reserve price of coal blocks to be auctioned.

The Coal Ministry has identified 54 new coal blocks for auction to the bidders for captive use in different sectors including 16 for power and 12 for steel.

Earlier, Coal Minister Sriprakash Jaiswal had said auction of coal blocks would not be possible last year because of the long process involved in it.