( ( At ( ( the time ) ( of ( the ( 1909 ( and ( 1910 Acts ) ) ) ) ) ) ) ( , ( ( ( coalbed ( methane gas ) ) ( -LRB- ( ( CBM gas ) -RRB- ) ) ) ( ( was ( considered ( ( a ( dangerous ( waste product ) ) ) ( of ( coal mining ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (NP (DT the) (NN time)) (PP (IN of) (NP (DT the) (CD 1909) (CC and) (CD 1910) (NNS Acts))))) (, ,) (NP (NP (JJ coalbed) (NN methane) (NN gas)) (PRN (-LRB- -LRB-) (NP (NNP CBM) (NN gas)) (-RRB- -RRB-))) (VP (VBD was) (VP (VBN considered) (NP (NP (DT a) (JJ dangerous) (NN waste) (NN product)) (PP (IN of) (NP (NN coal) (NN mining)))))) (. .)))
At the time of the 1909 and 1910 Acts, coalbed methane gas (CBM gas) was considered a dangerous waste product of coal mining.
(ROOT (S (NP (NNS Archaeans)) (VP (VBP produce) (NP (NN methane) (NN gas)) (PP (IN as) (NP (DT a) (NN waste) (NN product)))) (. .)))