although vs. in spite of

[Ecoke0005]

(1) Though strip-mining often caused irreparable damage to the natural environment, it was once used to supply half the coal produced annually in the United States.

(2) In spite of often irreparable damage to the natural environment, strip-mining was once used to supply half the coal produced annually in the United States.

can anybody explain why the sentence (1) is better than the sentence (2).
Is it because of the usage of "although" and "in spite of"? But then how are they different in these sentences?

thanks in advance.

[Bogdanno2]

Maybe because "of often" sounds terrible.