To restore the landscape, lignite ash (a waste product from energy production) found its way back into the huge pits left by open_pit mining. To make sure there are no embers, the ashes need to be slightly moistened. Residual moisture can be determined in real time using the RGI sensor. If the result is below the guide value, rewet the material. The sensor is surrounded by a robust housing that is mounted directly in the material flow behind the conveyor belt