Best method to dig out a drop pit

[Gary Soup]

what is the best technique when it comes to safely and effectively digging a large pit for the purpose of dumping garbage and screaming goblins

[Haethei]

Fully channel one layer at a time, from the top down. I haven't had any cave-ins if you just stick to a single layer until it's completely done. I usually don't even use the priority mining system, I only designate one layer at a time. Cave-ins are so annoying that I don't want to mess around with it at all

Carve out a staircase to access each layer so your dwarves can get back up and down when they need to get booze or sleep. I usually make the staircase 1 tile away from the wall of the pit, and dig through the wall to access the pit on every layer. This way, I have room to build a wall that seals off the pit again once I'm done, and the staircase is still usable and safe if you ever want it in the future

I'm pretty sure you can dump garbage with a tiny pit. Items will just stack at the bottom anyway. I love giant pits for trap areas though, because enemies will try to dodge weapon traps and fling themselves into the giant pit. Place flooring made out of a high-density material (gold, silver or lead floors) to significantly increase the amount of falling damage they take. A lot more fun than filling a hallway of cage traps.

You can also place fortifications around the pit hallway trap area for extra archer fun

[Gary Soup]

Thats exactly what im thinking :)

[Level12Boss]

Intriguing idea to have a dump pit.

How to do this safely?

Can you simply dig a 1x1 hole say 10 or 20 Z-levels deep, then designate the opening at the top as a dump zone? Dwarves won't fall in by accident? Or do you need to put a trap door cover over it?