[Grammar] Need punctuation help

[piyal]

Help me decide which one is correct. I am weak in punctuation, please have a look at the sentences below and tell me which one I should use.

"I did it before; I captured the gas coming out of tube well in my childhood, and I want to do it again, but only this time in an industrial scale." or " I did it before, I captured the gas coming out of tube well in my childhood; I want to do it again, but only this time in an industrial scale."

 

[Tdol]

I prefer the first, though you might be better off using a colon. Also, I would use on an industrial scale.

 

[piyal]

Thanks for your input. So should I drop the semicolon and replace it with comma, like this-
I did it before, I captured the gas coming out of tube well in my childhood, and I want to do it again, but only this time on an industrial scale."

 

[Tdol]

I would use a colon after before, but the semi-colon is better than a comma.