A widely-appealing and driven brand name which would be ideal for a cryptocurrency company.
The word "USMine" contains only six characters and only two syllables. Two-syllable names are exceptionally rare and very desirable. Leading companies using two syllable names include Walgreens, Ikea and Dropbox.
Usmine.com is a dot-com domain. Dot com domains are the most valuable top-level-domain in the world, famously used by websites like twitter.com. Owning a dot-com says that you own the word "USMine" online.