4(1)If before the expiration of 30 days from the receipt of notice under paragraph 3(1) above the acquiring authority do not state their willingness to treat with the owner for the payment of compensation the owner may work any of the underlying mines for which the acquiring authority has not agreed to pay compensation by proper methods and in the usual manner of working such mines in the district in question.E+W
(2)If any damage or obstruction to the undertaking is caused by improper working of the underlying mines—
(a)the owner of the mines shall forthwith repair or remove the damage or obstruction at his own expense,
(b)the acquiring authority may, without waiting for the owner to perform his duty, or in case of his default, repair or remove the damage or obstruction and recover their expenses from the owner in proceedings in the High Court.