Performance of vertical wick drains at the Atlas Moab uranium mill tailings facility.

Wick drains were designed to prevent increased seepage to groundwater following closure of the facility, in Utah, and to achieve the 90% consolidation required before placement of the final cap. Around 360 000 m of vertical wicks were installed in a triangular pattern on 3 m centres by specifically equipped track-mounted excavators. Each vertical wick was tied into a horizontal wick feeding into a drainage collection trench. The designed surcharge load consisted of sand ranging in depth from 6 m at the centre of the impoundment to 2 m at the edges, but funding limitations prevented the full load from being applied and the centre received only 1-2 m depth of sand. Performance of the wicks was better than predicted for the surcharge load used, but the required degree of consolidation will not be achieved in the required 18 months.
Wick drains were designed to prevent increased seepage to groundwater following closure of the facility, in Utah, and to achieve the 90% consolidation required before placement of the final cap. Around 360 000 m of vertical wicks were installed in a triangular pattern on 3 m centres by specifically equipped track-mounted excavators. Each vertical wick was tied into a horizontal wick feeding into a drainage collection trench. The designed surcharge load consisted of sand ranging in depth from 6 m at the centre of the impoundment to 2 m at the edges, but funding limitations prevented the full load from being applied and the centre received only 1-2 m depth of sand. Performance of the wicks was better than predicted for the surcharge load used, but the required degree of consolidation will not be achieved in the required 18 months.