TRYs Valuable Experience of combating the slump factor on the...

TRYs Valuable Experience of combating the slump factor on the existing smaller pits (They certainly had their issues) would give the company insight into whats needed in any future large Pit designs.
Also..any underground mining would have its flooding perils even though the valuable ore at lower depths would entice any miner to contemplate subject to the added costs needed to extract the gold from that sort of environment.