HE KNOWS ABOUT THE MINES.
( HE ( ( KNOWS ( ABOUT ( THE MINES ) ) ) . ) )
(ROOT (S (NP (PRP HE)) (VP (VBZ KNOWS) (VP (VB ABOUT) (NP (DT THE) (NNS MINES)))) (. .)))
He is aware that the mines exist. 
( He ( ( ( is aware ) ( that ( ( the mines ) exist ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBZ is) (ADJP (JJ aware)) (SBAR (IN that) (S (NP (DT the) (NNS mines)) (VP (VBP exist))))) (. .)))