Hi

Sorry in advance for not a good bug report, but i have not a server, i only play on it, so can't really test everything.

Forge 1277
Buildcraft 6.3.3
Caveworld 1.9.5

The Caveworld Mod adds a Dimension, especially a Underground world as a Mining Age.

A Quarry placed there loses his forced loaded Chunks Status after restart of the server. This means it is then possible that the Quarry tries to mine in unloaded Chunks, that messes things up. Especially it is possible that the Quarry produces an "unknown" Entity over and over by trying to mine a Block that is not existent. We had that issue several times, and at 4k unknown Entitities the server goes slow. The Entities are not visible, killing only with opis possible.
Can*t really test with Dimensions from other Mods if its a Caveworld Prob, but maybe theres a solution right away ;-)

Greetings Kropter