Why, in this digital age, would anyone think that a site visit would be required to make a decision on a partnership regarding a blind, or nearly blind target?  In this instance, travel bans are meaningless. 

Besides, site visits can be a convenient excuse for less-than-honest mining company employees to take mini-vacations to tourist destinations, the likes of which are all over Arizona - from Tombstone and Bisbee to the Grand Canyon*.  Besides, it has probably happened already to some extent.  You just would not hear about it under the terms of confidentiality agreements.

*Geologist friends of mine like to bring up the fact that South Mountain in Phoenix Arizona is the most studied mountain in the world.  It draws earth scientists from all points on the globe.  Why?  Not only is it geologically unique, but Pheonix has an international airport very near South Mountain - no long travel time nor camping in the wilderness - and it contains numerous world-class golf courses.  Tucson and Tombstone fit the same profile on a lesser scale - no grueling travel to remote locations nor sleeping in tents AND there are lots of nearby resorts to visit.

VP in AZ