A jack for installing a mine stopping panel includes an extendible post and a press for extending the extendible post. The press can have a lever movable between an actuated position and a non-actuated position and operative to extend the post as it moves toward the actuated position and retract the post as it moves toward the non-actuated position. A yieldable biaser yields when the post is extended to extend the mine stopping panel and the mine stopping panel engages a mine surface with sufficient force to crush a stopping seal and anchor the stopping panel. The press can comprise an over-center toggle linkage.