So, in an evil campaign I'm in, I don't really have the cash to pay the 50000 or so GP it takes to make a shadowsteel golem.

On the other hand, opening a portal to the plane of shadow and sending in four hundred miners seems doable (they want, what, a GP a week each?). (Plus it opens up opportunities on the DM's part for shadow-monsters to attack the miners, prompting more adventures)

Suggestions? Tips? Important details? How the hell do I open a portal to the plane of shadow?