Rain will usually only cause short delays, maybe up to a week or...

Rain will usually only cause short delays, maybe up to a week or two under the worst situations and such long delays should only happen once in the mines life. If the site management doesn't learn from these events then you need to replace them. Standard practice coming into the wet season - prepare and repair site drainage and have the pumps ready and a plan. The Tanami area is by no way wet and if you want to talk rain, look at some of mines near the tropics where the rainfall is measured in meters.
Often the problem is getting the people in and out. If a mine is prepared well, they will carry several weeks of supplies and disruptions kept to a minimum. We had a big rain at Nifty a few years back and the biggest problem was we started to run low on grog. We fixed that by flying in a few tonnes.
My opinions only