This paper reviews a research program, being conducted by the Office of the Supervising Scientist and Macquarie University, investigating the hydrology and erosional characteristics of waste rock matenal at the Ranger Uranium Mine. The significance of the problem is described, the experimental methods are briefly outlined and some results on the infiltration processes of the waste rock dump are presented. A second paper by Williams, RiJey and Gardiner describing infiltration experiments under simulated rainfall on the waste rock dump will be presented next.