overburden

Plural: overburdens

Noun

• the surface soil that must be moved away to get at coal seams and mineral deposits
• an excessive burden
• The rock and subsoil that lies above a mineral deposit such as a coal seam, or any other underground feature.
• A sterile stratum that lies above the stratum being investigated

Verb

• burden with too much work or responsibility
• load with excessive weight
• To overload or overtax.

Synonyms

overload, mullock, swamp