Minecraft wiki entry for Mining, associated text: A finished quarry with obsidian and lava at the bottom.
A quarry in construction.
A recently begun quarry. There is a convenient, easily accessible ledge with chests, furnaces and a crafting table.
The inside of a quarry.
An elaborate 64 by 64 blocks quarry in the making.
A 16×16 quarry being looked at from the top.
Looking up from the bottom of a quarry mine.
An unfinished 20×20 quarry.
A quarry to bedrock.