Rhondda Cynon Taf Council staff were at the scene of a land collapse in Cwmaman.
Large machinery, including a pump and JCB, have been brought to the scene in a bid to clear water from the bottom of the collapse and clear the edges in a bid to establish exactly what has happened.
A spokeman said: “Until the exact cause of the collapse is known, a permanent and effective resolution to the situation cannot be delivered.”
Until investigations are complete, the site remains cordoned off and warning signage has been installed.
The land has collapsed in the car park at the rear of two blocks of flats in Brynmair Close, Aberaman. The incident was reported to the Council on Tuesday (Dec 29) and officers have been on site ever since.
Due to the proximity of the collapse to the blocks of flats, the residents in three properties have been evacuated by their landlord, RCT Homes. Two are staying with their families and the third is in B&B accommodation.
The Coal Authority has already attended the incident and confirmed the collapse is not related to previous mining activity in the area.
Council officers are working on the assumption the collapse is in relation to a culvert, but cannot be precise until the water has been drained from the bottom of the hole, which is some 15 ft deep, and the sides cleared to allow safe investigation.
