Surface coal mining activities may not be conducted closer than 500 feet to any point of either an active or abandoned underground mine, except to the extent that: For active underground mines, including abandoned sections of active mines: The nature, timing, and sequence of the operations are jointly approved by the Mine Safety and Health Administration and the Bureau; and The activities result in improved resource recovery, abatement of water pollution, or elimination of hazards to the health and safety of the public; For abandoned underground mines: The nature, timing, and sequence of the operations are approved by the Bureau, and The activities result in improved resource recovery, abatement of water pollution, or elimination of hazards to the health and safety of the public. Surface mining activities shall be designed to protect disturbed areas, including spoil disposal sites, so as not to endanger any present or future operations of either surface or underground mining activities. Deep mine areas containing significant amounts of impounded water shall be bypassed in open-pit mining unless plans for water handling during and after mining are submitted with the application and demonstrate that there will be no adverse effects.