. "Black Vein Coal (South Wales)"@en . . . "Black Vein Coal (South Wales)"@en . "Coal."@en . "stable"@en . . . . "BLVC"@en . . "298.9"^^ . "359.3"^^ . "Coal. Stratified bedrock. Occurs onshore. Deposited during the Carboniferous Period (359.3-298.9 Ma BP)."@en .