(S (S (BASENP (DT The) (NN mine)) (VP (VBZ is) (VP (VBN suspected) (S (VP (TO to) (VP (VB have) (VP (VBN collapsed) (PP (JJ due) (PP (TO to) (NP (NP (BASENP (DT a) (NN build) (RP up)) (PP (IN of) (BASENP (NN underground) (NN water)))) (SBAR (WHNP (WDT which)) (S (VP (VP (VBD caused) (S (NP (BASENP (DT the) (NN mine) (POS 's)) (NNS supports)) (VP (TO to) (VP (VB buckle) (CC and) (VB collapse))))) (COMMA ,) (S (VP (VBG blocking) (BASENP (DT all) (NNS exits))))))))))))))))) (PERIOD .))