(S (S (BASENP (DT The) (NN mine)) (VP (VBZ is) (VP (VP (VBN owned) (PP (IN by) (BASENP (NNP Massey) (NNP Energy)))) (CC but) (VP (VBN operated) (PP (IN by) (NP (BASENP (NNP Performance) (NNP Coal) (NNP Company)) (COMMA ,) (NP (BASENP (DT a) (NN subsidiary)) (PP (IN of) (NP (BASENP (NNP Massey)) (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (BASENP (DT the) (ADJP (RB fourth) (JJS largest)) (NN coal) (NN producer)) (PP (IN in) (BASENP (DT the) (NNP US)))))))))))))))) (PERIOD .))