Any compensation payable under this act for silicosis, anthraco-silicosis or coal-worker's pneumoconiosis as defined in section 108(q)¹ for disability occurring on or after July 1, 1973 or for death resulting therefrom shall be paid as follows: if the disability begins between July 1, 1973 and June 30, 1974, inclusive, the employer shall pay twenty-five per centum and the Commonwealth seventy-five per centum; if the disability begins between July 1, 1974, and June 30, 1975, inclusive, the employer shall pay fifty per centum and the Commonwealth fifty per centum; if the disability begins between July 1, 1975 and June 30, 1976, inclusive, the employer shall pay seventy-five per centum and the Commonwealth twenty-five per centum; and if the disability begins on or after July 1, 1976, all compensation shall be payable by the employer. The procedures for payment of compensation in such cases shall be as prescribed in the rules and regulations of the department.