A tradução é mesmo essa.
Vou deixar-lhe aqui umas referências:

Canadian Tax Highlights
... New mining taxes include a progressive surface tax, an exploitation tax based on
monthly production, and a production tax payable on extraction of a mineral. ...
www.ctf.ca/ctfpubs/cth/000215.htm

Macleod Dixon Article: Venezuela Mining Bulletin
... be subject to the following taxes: 1. A surface tax to be paid quarterly starting
the fourth year of the concession was granted. This tax is calculated as a ...
www.macleoddixon.com/04public/Articles/04carmin.HTML

African Countries Economic Reports
... by the same titleholder; A mining rights surface tax is payable annually on a per
hectare basis during reconnaissance and exploration. It is fixed generally at ...
www.newafrica.com/business/output.asp?TitleID=5594

Boa sorte!