The disused coal tips have been there for many decades and the regular inspection programme is designed to ensure any changes are identified early.
Mae'r tomenni glo segur wedi bod yno ers llawer o ddegawdau, ac mae'r rhaglen archwilio reolaidd wedi cael ei chynllunio i sicrhau bod unrhyw newidiadau yn cael eu nodi'n gynnar.