Back on June 24, I told you about the one mining stock that’s the only U.S. source for the critical strategic metal, antimony. The company is Perpetua Resources (PPTA) and, at that time, I recommended buying the stock at its then-current price of $6.83. Since then, there has been a lot more news regarding antimony and export restrictions on it from China. Perpetua stock is now up to $8.64 a share (+26.5%), and there is a lot more upside to come. Let me explain why. What Are the Uses for Antimony?Antimony is a shiny gray minor metal known since ancient times when it was used in medicine and cos…