Lower Kurast spawns one or two 'campfires'. Around these campfires there is always 1 building to the north which has one chest, and 1 building to the west which has two chests.
The chests inside these buildings are bugged, and have an unusually high chance to drop high runes up to
Ber in Hell difficulty. Therefore this area is often 're-rolled' on single player until a 'perfect' seed is found, where the campfires spawn close to the area's waypoint.
This allows you to open six chests within around 30 seconds, making it the fastest way to farm high runes.
Number of elite pack spawns:
Normal: 1 - 2
Nightmare: 4 - 6
Hell: 7 - 9
Teebling Admin