[ceejayoz]

"thanks to the good pumping system" (guess what powers that) and "by the late 19th century the seams were becoming exhausted" indicate the practical limitations faced by that.

[Turing_Machine]

> "thanks to the good pumping system" (guess what powers that)

In the 19th Century?

Steam engines that burn part of the extracted coal. What else?

> by the late 19th century the seams were becoming exhausted

Those particular seams, maybe. They're not the only seams, dude.

I think we're done here.