Board Thread:Questions and Answers/@comment-173.164.54.242-20130716025327/@comment-5627887-20130716182817

Quarries keep the chunks they are located in loaded but not, in my experience, the power pipe network connected to them that lies outside this immediate area. I have had issues with distant quarries stopping unexpectedly that turned out to be because the edge of the quarry was on a chunk boundary, and the piping connected to it was just the wrong side of the boundary and remained unloaded, so the quarry stopped receiving power. If you can't figure out why the machines keep on running, one solution would be to cut the flow of power to your machines using an EU-Splitter Cable and wireless redstone, so you could isolate the wiring going to your machines using a Wireless Remote.