A heating system for a subterranean mineral formation according to embodiments of the present invention includes a casing positioned in a bore in the subterranean mineral formation, the casing having an outer surface and an inner surface, a heating element positioned within the casing, a surface connection system having a first end coupled to the heating element within the casing and a second end at a top ground surface above the subterranean mineral formation, a heat transfer fluid contained within the casing, the heat transfer fluid configured to transfer heat between the heating element and the inner surface of the casing, wherein at least a portion of the heat transfer fluid is undergoing phase changes between liquid and gas in order to regulate a temperature of the casing. Fins may be included on the outside of the casing to enhance heat transfer.