Aussie minerals are NOT privately owned, rather the Govt. retains rights to them. when we were over there my company had thousands of sq. miles in the Bowen Basin to explore for coal. we drilled the hell out of that area to delineate 175 sq. miles to claim for our mining operations. then royalties are paid to the "Crown" on all produced.
so in this case these companies are looking at large blocks of land for mineralization, using any means to identify the best targets for ultimately leasing and drilling.