(under subclass 256) A process in which the earth is cracked to produce a fissure or fissures therein, or in which fluid introduced into the pores of the earth chemically reacts with the earth or deposits in the earth to enlarge the pores of the earth.
(1) Note. See (1) Note in subclass 307 for a discussion of the meaning of "deposits in the earth".
(2) Note. The fracture or pore enlargement must be effected
by some cause other than the heat of the in situ combustion itself. A process in which the heat of the in situ combustion is said to cause fracturing or increase of permeability is classified on other features.
