(S (S (BASENP (DT A) (QT (DQL ``) (NN bump) (DQR ''))) (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (NP (BASENP (NN coal) (NN shooting)) (PP (IN out) (PP (IN from) (NP (BASENP (DT the) (NNS walls)) (PP (IN of) (BASENP (DT a) (NN mine))))))) (PP (JJ due) (PP (TO to) (BASENP (JJ extreme) (NN pressure))))))))) (PERIOD .))