I think that explanation is too complicated. AAR is far from...

I think that explanation is too complicated. AAR is far from being a producer. There might be some short-term production, but that is just a cash infusion (a large one). What do you think will it cost when you have favorable geology + trucking + contractor milling? Pretty low costs. So high margin. And only a very small portion of gold in the ground extracted. Meanwhile you have ongoing exploration where costs tend to rise with the gold price (e.g. drill rigs get scarce), so exploration is less sensitive to the gold price than production. From a fundamental pov I do not see why this stock should show much leverage to the gold price. Stocks with much leverage are way worse than plain undervalued stocks of course. If everything goes well both show the same result. If thing go wrong leverage works to the downside too while undervaluation works as a buffer against losses.
Low share price (relatively speaking) is a result of disinterest caused by the low gold price. That's all. The market (often wrong in individual small cap stocks) may be blind and not recognize yet the extraordinary potential you get here.