wall elements comprising a plurality of rigid blocks and a plurality of compliant sealing members the rigid blocks and compliant sealing members are combined in courses to form a wall which extends over substantially the entire cross section of a tunnel being stopped the sealing members being interposed between and or around the rigid blocks in a uniform or nonuniform arrangement throughout the extent of the wall so as to accommodate convergence loads imposed on the wall and form together with the rigid blocks a barrier against the flow of gas through the tunnel application_number US 49836283 A description referring to fig1 of the drawings a mine stopping 10 of the invention is shown erected in a coal mine tunnel 11 having a floor 12 a ceiling 13 and side walls 14 the stopping extends across the entire cross section of the tunnel and closes the tunnel against passage of air and other gases mine stopping 10 comprises a composite structure made up of rigid blocks 15 with stress compliant material 16 interposed throughout the structure the rigid blocks 15 of the stopping can be made from conventional materials such as e g cinder slag and gravel aggregates combined with sand and cement with or without mortar between the joints 17 of adjoining rigid blocks the block stoppings.