A guarantee of a minimum production royalty nested within a provision describing the discretionary commencement of mining operations does not guarantee such a royalty if the party elects not to operate the mine.
http://media.ca7.uscourts.gov/cgi-bin/rssExec.pl?Submit=Display&Path=Y2018/D08-10/C:17-2889:J:Rovner:aut:T:fnOp:N:2200780:S:0
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.