| |
 Created
when ground water is pumped
from a well or underground mine. Groundwater flow changes direction in a
portion of the watershed. Instead of moving toward the natural discharge
area, the groundwater within the influence of the pump flows toward the
well (or mine) from every direction. The pumping well creates an artificial
discharge area by drawing down (lowering) the water table around the well.
This area of drawdown is
called the cone of depression. Molycorp has created a large cone of depression
through such a drawdown process, from pumping out its underground workings.
The theory is that most groundwater contaminants will be captured in the
cone of depression and safely removed from the groundwater by continued
pumping. The success of capturing acid
rock drainage using this method has not been adequately demonstrated. |
