Wow, thanks murrayjames! That's a really thorough breakdown of the poem. You're right, I know nothing about the period it was written in, so it's difficult to comment on the context under which it was written. I really like your breakdown of the "toil/toil/toil/purity" and the conclusion that purity is only revealed at the end of the process. I think you're spot on, and I hadn't really thought about it like that.

As for "凿", my girlfriend (she's from 贵州) told me that it is how you say chisel and, moreover, it's still commonly used - i.e. not archaic.

My very poor attempt at interpreting “烈火焚烧若等闲” would be something like "Raging flames (aimlessly?) ablaze". Would that be a good translation?? :S