A Non-Injury Accident occurred on the MMU. No. 005-0 Section during retreat mining. A coal bump or outburst occurred on the 2 Left off South Submain. The coal bump or outburst was on the right rib of the No. 3 entry. All employees were withdrawn from the mine. MSHA was notified of this event. Upon MSHA's arrival to the mine site an investigation of the coal bump or outburst began.