A team of Goa Reserve Police moved stacks of files from the office of Director of Mines and Geology, Prasanna Acharya, to an undisclosed site.
Acharya confirmed that the files contained royalty 'challans' (receipts) and NOCs (no objection certificates) issued since 2009 but declined to reveal where the documents had been moved.
Acharya told reporters these files would be scanned and secured so that they are not tampered with.
These files are under scrutiny as part of the state government's investigations into illegal mining and export of iron ore from Goa.
The NOCs and challans, issued during the tenure of former Director of Mines Arvind Lolienkar, are being scrutinised to find out any illegalities, officials said.
Chief Minister Manohar Parrikar had earlier told the Assembly that a panel of Chartered Accountants would be formed to go through these papers.
The Goa Government is investigating the iron ore mining scam involving crores of rupees allegedly under the previous Congress-led regime.