Coal barrier | Article about coal barrier by The Free Dictionary
coal barrier[′kōl ‚bar·ē·ər]
A protective pillar composed of coal.
References in periodicals archive
A coal barrier
will be left in place and alkaline materials will be placed on the mining pit's floor to establish an "infiltration basin" that will release an alkaline discharge into a nearby stream that is negatively impacted by acidic mine drainage.