The efficacy of the Tekran® 3300 Hg CEM has again been demonstrated with a successful installation at two Pre-Calciner cement plants in the US. The Tekran® units have been in continuous operation mode for many months. Both units passed RATA validation and met all PS 12 A and Part 75/60 requirements. Both units successfully capture valid data during mill-off and mill-on conditions, in spite of the variations in mercury emissions. (See chart). The Tekran® 3300 system software charts mercury emission variations resulting from process control changes including carbon injection and mill input.