The following is the 1964 version of the constitution of Minnesota, a U.S. state. It is an amendment of the 1962 version, which was in effect previously. The main aims for the 1964 amendment were (1) to remove obsolete language from constitution, (2) to prevent amendment or repeal of taconite tax policies for 25 years, and (3) to authorize legislature to impose limitations for not more than 25 years on taxation of copper and nickel mining.