A method of recovering hydrocarbons from hydrocarbonaceous materials can include forming a constructed permeability control infrastructure. This constructed infrastructure defines a substantially encapsulated volume. A comminuted hydrocarbonaceous material can be introduced into the control infrastructure to form a permeable body of hydrocarbonaceous material. The permeable body can be heated sufficient to remove hydrocarbons therefrom. During heating and removal of hydrocarbons and subsequent thereto a positive pressure can be maintained within the encapsulated volume by means of a non-oxidizing gas to expedite flushing of hydrocarbonaceous material, inhibit unwanted entry of oxygen into the encapsulated volume and remove recoverable hydrocarbons following the heating process.