43 CFR § 3832.45
How do I obtain any minerals that I discover within my tunnel site?
June 11, 2020
(a) Even if you have located the tunnel site, you must separately locate a lode claim to acquire the possessory right to a blind vein, lode, or ledge you have discovered within the boundaries of the tunnel site sidelines.
(b) The date of location of your lode claim is retroactive to the date of location of your tunnel site.