Just follow the moneyAn article released yesterday about majors taking a stake in small cap developers/explorers the buying them out.
They specifically reference Eldorado's 15% stake on Feb 2016 of Intergra for $0.50 and last week bought the remaining 85% at $1.21.
It's not apples to apples but if we apply the same scenario to South32's purchase of AZ at $2.45 the resulting price is around $6.
After another years worth of drilling, a rising zinc price and a new resource estimate, $6 may be cheap.
https://www.kitco.com/commentaries/2017-05-19/Just-Follow-the-Money-when-Investing-in-Junior-Miners.html