Depending on your system revision, it could be located a little differently, but in current software releases the path to it is:
Users and Devices
Advanced Configuration
Analog Telephones
Analog Sets
From there you can do an Export to a CSV file, it will give you Cabinet, Shelf, Slot, Circuit, extension, etc.
What kind of trunks? Analog lines or a digital circuit (we don't see many Mitel's with analog lines anymore)?