Determination of disability - the disablement would be taken as total for the purposes of award of compensation under section 4(1)(b) of the Act regardless of the injury sustained being not one as specified in Part I of Schedule I of the Act - The proviso to clause (l) of sub-section (1) of Section 2 of the Act does not dilute the import of the substantive clause - Rather, it adds to it by specifying categories wherein it shall be deemed that there is permanent total disablement.