coal clay

coal clay

[′kōl ‚klā]
(geology)
References in periodicals archive ?
Extremely acid (sterile from reclamation perspective) coal clay stone from the coal preparation plant Ledvice was one kind which created a vast phytotoxic area in the dump.
The experiment proved substantial improvement of sterile coal clay stones properties and the method is, because of great production of the stabilizer, very prospective.