The mummies have been pumping their special glycol out of the ice since time immemorial. It's what keeps them operating in the coldest months. See, their ability to move is all based on hydraulics--the ichor getting pumped around inside them--and the glycol keeps it from freezing up. It's how they move around, and sometimes show feats of tremendous strength. Their "Ice Pyramids" are the covers for the glycol wells and pumps and whatnot. That sphinx-looking structure is a storage tank.

We keep their perimeter under surveillance. The Ice Rangers that is, and our giant Japanese huskies. We couldn't do it without them. Sometimes a new Mummy King will arise and get all the mummies riled up about heading to the sea, stealing some ships, and ice-pirating their way to warmer climes. We keep an eye on that and make sure they stay penned in.

Col. Robert Plume
D.S./D.O./M.P.
The Lodge, Amundsen–Scott