Exploration:

Expand existing maps to add area.

Rescue mission:

A team in the pits is cut off or trapped and needs rescue.

Guard a Vein:

One of the remaining veins of mithril has been found.

Supply:

Carry in supplies, healing potions, and ammo.  Carry out mined ore.

Explore a Gate:

A magical gate has been found.  Take a team through and back.

Burn a bridge:

There are many bridges over deep cracks and smoking pits.  Chaos uses them to move troops.

Install an Elevator:

Replace the old Dwarven elevator.  Used for rapid deployment to the deeper levels.

Baby Sitting:

Many times nobles want to bag a chaos creature.  They need professional experienced protection.