Sensitivity of Very Hard Pliocene Marl

Marls of a very high initial strength, are sandwiched between late pliocene lignites in the extended lacustrine deposits of Ptolemais, Greece. As they are extracted as waste from deep open pit lignite mines they are carried by conveyor belts and deposited over mountainous tailings. During transport they undergo vibrations and progressively disintegrate arriving at the disposal site in a slurry-like consistency. They never recover any fraction of their initial strength. Present note describes the geotechnical properties of these sensitive and nonthixotropic marls.