Preliminary digs have been more than successful. It's extremely surprising to find such a high quantity of the product this close to the surface. If I didn't know better, I'd think it was growing.
On one hand, this gives us an advantage. Without having to work with the old families back in Orzammar, or even take this through official guild channels, our families stand to make a killing. On the other hand, the proximity to the surface and to the populated areas of Redcliffe raises an interesting challenge. The war between the mages and templars should keep people out of the area for now, but as soon as the humans are done trying to kill each other, any operation we start will be uncovered.
If we're going to take advantage of this opportunity, we need to keep people out of the area. I'd recommend manufacturing some bandits. This part of Ferelden is lousy with them, so they shouldn't attract much attention, and nobody will have trouble believing that bandits would stake out some territory. By the time anyone uncovers the operation, it'll either be tapped out, in which case we'll be gone, or we'll have the operation running smoothly, in which case we'll be wealthy enough to deny everything and throw some money at the throne by way of apology.
Talk to the families and make it happen. This is too good to pass up.