In its present condition, the dam of the tailings pond is less stable
than is recommended by international practice. A surveillance system has
been established to observe both vertical and horizontal soil movement
and the buildup of stresses in the soil. The stability of the dam
depends primarily on erosion by shore processes and the consequent
reduction of the counterbalance, as well as the reduction in strength of
the Cambrian clay underlying the dam caused by creep and by water
percolating to the bottom of the pond. The most critical need is to
enlarge the counterbalance and to stop erosion. The surveillance system
should be supplemented with a system of inclinometers. Monitoring of
coastal processes should be continued. At present, the hydrodynamic
stress on the dam is minimal because the pebble layer allows drainage of
water out of the tailings pond and into the sea. The regulatory
requirement to end emissions into the Baltic Sea must be met without
causing undesirable hydrodynamic stresses on the dam. This could be done
by covering the pond and diverting precipitation water. 9. References I.
Report on Topographic-Geodetic Studies at the Tailings Pond. 1965, No.
A-4-01187 (in Russian). 2. Report on Geotechnical Studies at the
Tailings Pond of Plant PO Box 22. 1965, No. 64691 (in Russian). 3.
Report on Topographic-Geodetic and Geotechnical Studies at the Thennal
Power Plant's Ash Impoundment. 1976, No. 15740 (in Russian). 4.
Technical Report on Topographic Planning of the Thennal Power Plant's
Ash Impoundment. 1979, No.