You can make up bags of paydirt, or concentrates with gold in them,
you can Not sell common materials such as sand, gravel, dirt or stone.
other people still can't take sub-surface materials from a persons claim, not
without use permit or lease from BLM or FS and even then they would have
to coordinate with the claim owner and follow a set of guidelines, like say your
claim also has a rock quarry, as far as BLM goes, someone using materials from your claim
could lead to the miner saying, I haven't checked those for valuable minerals yet.
Don't really know enough about the situation, you could cherry pick what you want to hear
or give us a more complete story to get a more accurate response.