Correspondence: Processing of coal, oil sand and heavy oil in situ by electric and magnetic fields

Two important improvements in the technique for the heating of solid fossil fuel deposits by eddy currents induced by an alternating magnetic field have been discussed. One is the injection into the fuel layer by pressure, from the surface, of a hot, saturated, high-conductivity, saline aqueous solution. The second is the use of a composite casing/conductor, consisting of an inner steel tube welded to an outer copper tube. The eddy-current heating plan is better than the dielectric heating plan by orders of magnitude on all major points of comparison, and is the only option that from an objective point of view is really a candidate for a major long-term energy source.