43 CFR § 3505.62
Under what conditions will BLM extend my prospecting permit?
June 11, 2020
You must prove that:
(a) You explored with reasonable diligence and were unable to determine the existence and workability of a valuable deposit covered by the permit. Reasonable diligence means that, in BLM's opinion, you drilled a sufficient number of holes or performed other comparable prospecting to explore the permit area within the time allowed; or
(b) Your failure to perform diligent prospecting activities was due to conditions beyond your control.