Prices went up by 45-50 per cent during the two-day auctions that ended on Saturday and touched a high of Rs 3,900 per tonne, against the base price of Rs 2,750. The Supreme Court-appointed monitoring committee had facilitated 876,000 tonnes of iron ore with a Fe grade of 55 to 67 per cent for this round of auction. Steel companies picked up 364,000 tonnes, or 41.5 per cent, of this. About 232,000 tonnes were sold yesterday and the remaining on Saturday. Of the total 364,000 tonnes, 44,000 tonnes came from NMDC. JSW Steel, Kalyani Steel, Mukand Steel, BMM Ispat and MSPL Ltd were the major buyers.