Long-Term Monitoring of Water Infiltration Through Covers atWhite's Waste Rock Dump at the Rum Jungle Mine Site UsingLysimeters

摘要

Monitoring of water infiltration into White’s waste rock dump at the RumrnJungle mine site in the Northern Territory, Australia, started in 1983, andrnhas since produced a unique and long-running data set. Following closurernof the uranium mining operations at the site, a soil cover was constructedrnon the dump in 1984 primarily to reduce water infiltration into, and thernquantity of low quality effluent out of, the waste material. Thernperformance of the cover in reducing water infiltration has beenrnmonitored using ten lysimeters installed across the dump prior tornconstruction of the cover.rnOver the past eight years or so, the average infiltration rate asrnmeasured by the ten lysimeters appears to have risen compared to thernearly years of monitoring. The significance of this apparent increase isrndiscussed given the variability observed in the data from individualrnlysimeters, and the variability in the rainfall. Estimates of the infiltrationrnrate as measured by each of the lysimeters are examined using statisticalrntools. It is concluded that the infiltration rate has increased with time andrnwith increasing rainfall. The increase with time is a stronger factor thanrnthe increase with rainfall. It is further surmised that the cover system atrnthe locations of the lysimeters is less effective now at reducingrninfiltration into the dump than it was when newly installed.