Goa might have to face a "Japan-sized" calamity if rampant illegal mining in the state is not curbed, a spokesperson for the NGO Bharat Swabhiman Trust (BST) said on Monday. The organisation, led by yoga guru Swami Ramdev, had zeroed in on illegal mining as one of the most critical issues concerning Goa, president of the group Bharat Ghullanawar told a press conference here.