I actually did the opposite of what you're asking.
I had been constantly supplied tons of gold to get engineering and blacksmithing up together, without the need of mining.
However that was awhile ago.
I had engineering and blacksmithing up to like 260 each, but now no real way to generate cash to get either any higher.
Took a long time but I decided to drop Blacksmithing (still hurts) and keep Engineering (to blow stuff up, duh) and get mining.
Engineering is fun if you go all the way, and the tools you get (i'm a Goblin engineer) can actually help pretty well in most situations. Blacksmithing I believe is only really good when you max it out.