(2) The use of lands by such corporation for the purpose of the discharge and natural distribution of smoke, fumes and dust from any such mill, smelter or other works for the reduction of ores, under the conditions prescribed in this section hereby is declared to be a public use.
(3) The right of eminent domain shall not be exercised by such corporation:
(a) Beyond a radius of four miles from such mill, smelter or other works for the reduction of ores.
(b) On any land situated within a radius of five miles of the corporate limits of any city in the state.
(c) Until after such corporation has acquired the right to use 50 percent of the area of the lands within a radius of four miles from the mill, smelter or other works for the reduction of ores.