The chap has had issues with at least one of his employers.
If you wish to check his cred as a gold geo, you need to see how expected gold grades from proven JORC reserves match measured gold grades from treated ore. You will need to access data on ore dilution and percentage recovery as well. The red flag needs to be waved when measures grades less dilution are less than proven JORC reserve grades.
Gold mines succeed or fail depending on how accurately the geology team measures the grade of ore in the ground.
