Immediately after registering the cases, CBI conducted searches at various places including the premises of the companies named in the FIR.
The agency said that searches were being conducted in Delhi, Nagpur, Mumbai and Chhattisgarh.
With the registration of two more cases, the number of cases lodged by CBI to probe alleged misappropriation in coal blocks allocation has gone upto 18.
The allegation against Central Collieries Company Ltd was that it sold coal in the open market against the concept of captive allocation of coal blocks for a specified end use.
The case has been registered under sections of the Indian Penal Code dealing with forgery and criminal breach of trust, CBI said.
In the second case, CBI alleged that Prakash Industries had misrepresented facts about the net worth of the company while applying for coal blocks.