Tunisia's sovereignty over its natural resources has become a controverisal issue after the 2011 revolution. One of the most notorious cases that has sparked outrage is the allowance given to a French company to extract Tunisian salt for the same price since 1949.
Salt is difficult to extract from the earth 
( z1 difficult :domain ( z2 extract :ARG1 ( z3 salt ) :ARG2 ( z4 planet :name ( z5 name :op "Earth" ) ) ) )