Abstract: A method of making a nonporous, substantially liquid-impermeable cryogenic barrier within the Earth, and a nonporuous, substantially liquid-impermeable cryogenic barrier. A triple array of casings extends along respective sets of central axes from arrays of spaced apart locations on the surface of the Earth. A refrigerant is flowed through the two outer arrays of casings to form overlapping, continuous cold columnar regions extending along and about the respective central axes of the casings. The intermediate region between the two outer arrays of casings contains the central array of casings. A heat transtar agent is flowed through a selected subset of casings within the central array of casings to establish a relatively warm region between the continuous cold regions.