Ruminations

The play in the mines can evolve in many ways depending on the characters' course of action. If the players launch a direct assault against the orcs, they can quickly clear out the two or three clusters of them in the chambers near the exit. At this point, they could either move into room 11, past room 7 or down to level two.
Room 7 and level 2 can give opportunities for raw, underground dungeon crawl situations. Maybe, past 7 leads to a monster infested section, even down to the second level for that. Going straight to level 2 from area 6 leads into the section being worked, so less direct threats, subtler enemies, and more treasure, although I think the storyline put forth yesterday that the miners would be intentionally directing the orcs away from mineral rich areas is likely. This area of the second level would be more about exploration and investigation than combat, with random wandering encounters. Another option that would fit nicely would be a heavily trapped area set up by the miners as they worked to try tipping the scales against the orcs.
I'm curious about areas 12-17... There isn't really a reason to head that direction. Once the guards at area 6 are dealt with, it seems likely the miners at area 11 would be encountered, and there would be no reason to continue into the mine. It becomes vital at this point to flood the mine with orcs and drive them deeper into its tunnels.
The trouble with that thought is that with the background I've sketched out, the miners would be inclined to go down through their new tunnel to level three to find the Hardys and work out an escape plan. I like that idea. The Hardys are on the lower level, and the party needs to find them and escape. The miners know their way around the mine, but don't know where the Hardys are. The Hardys use as much time as they can fully exploring the mine, and could be found in practically any location, as desired.
This is all great for exploring the lower levels, but doesn't address the original question in my mind... why would the party ever explore areas 12-17? I've got a germ of an idea to put orcs there, as a "freelance" mining area, a covert exploration by the tribe to line their individual pockets at the expense of Granak. It seems perfectly in line with orc mentality, selfish and duplicitous. It would also give a sense of danger to that direction that would affect the miners, and make them more likely to go down to level three and work their way out of the mine. It would also be a great way to have reinforcements arrive quickly, and in a surrounding fashion, increasing the sense of urgency for party and miners.
Another possibility would be that the orcs have brought something more terrifying with them, and let it loose in that section of the mine to keep any natural creatures at bay as well as corral the miners in their chamber. Both actually work together, I think, so that will be the way to go. Now, I'll just need to think of what that could be...