Tensile failure mechanism enhanced by uncovering coal area during coal and gas outburst

• Gas-driven tensile failure is the dominant mechanism in coal and gas outbursts, and its influence is amplified by the uncovering coal area. • Increasing uncovering coal area leads to higher gas emission volumes, larger outburst hole deflection angles, greater roof displacement, and larger damage zones. • Tensile failure criterion predicts coal failure regions that largely coincide with mixed failure criterion, but far exceed those predicted by shear failure criterion. • A progressive cyclical method of coal uncovering was developed, providing a novel approach for safe coal mining.