Bydd y gwaith ym Mhorth Mawr yn adeiladu ar y pecyn cychwynnol a gafodd ei gwblhau sawl mis yn ôl i sicrhau amodau priodol ac addas ar gyfer gwaith cadwraeth hanfodol ar gyfer y gofeb.
The works at Porth Mawr will build on the initial package that was completed several months ago to ensure appropriate and suitable conditions for critical conservation of the monument.