I would suggest if you have the money, research,research,research, then purchase the land for yourself if possible. It takes away a lot of red tape and can assist in speeding up the lease process, it also has the added advantages of not having to cough up royalties, which can go the way of the titanic in so many ways.
As Loamer stated old mates is the best way, trusted people is the only way your going to come out on top otherwise you will want to pay seriously high wages to stop some of the gold going for a walk out the front door.
Not so long ago there was 25acres for sale in the Bendigo paper it was stacked full of old workings, right in heart of the local gold fields with power running right past the front of the property, a perfect little way to make a fortune, and once your done, rehab, house, shed, and flog it off. It was for sale for 225k, i was about 225k short damm it, it was only in the paper for two days, and then gone, gotta be quick.