NEW DELHI, 31 JAN: The CBI has registered two cases against unknown officials and private companies for allegedly causing a loss of over Rs 1,000 crore to the government exchequer by making false declarations in transportation of iron-ore and its end use. The cases were registered against unknown officials of ministry of railways and Central Excise of Haldia Commissionerate and two private companies ~ M/s Rashmi Cement Pvt Ltd, Jhargram and M/s Rashmi Metallic Pvt Ltd, Kharagpur ~ based in West Bengal, CBI officials said.