Searching online, it seems to be comparing to coal miners specifically, not the industry as a whole. In any case, what conclusions are you drawing from this?
I mean, assuming it's true, the obvious conclusion would be that there should be reasonable limits on what is done to save such a small industry. Looks like there are 40-45k people employed in coal mining in the US, depending on who you ask. _Even if there was no downside to keeping it going_, that would probably only be worth modest government action to keep it on life support; it's simply not a big industry.
Maybe all of these emissions are coming from yoga classes instead of coal mines? We've been looking in the wrong place all along.
Not OP, but I have heard the comparison used when discussing jobs. There tends to be rhetoric in the US that transitioning away from coal and oil will lead to large job losses, so this is an anecdote disproving it.