Overlapping utility pipes were this week hampering engineers efforts to repair a collapsed Victorian sewer in Preston.
The excavation will need to be wider than originally thought, because other utility infrastructure is blocking access to the sewer from above.
Emergency work to remove the collapsed section of 161 year old clay sewer and replace it with 20m of new concrete pipe began last week (News last week).
Engineers from KMI water, a joint venture comprising Kier Construction, J Murphy & Sons and Interserve Project Services, will this week widen the 2m wide, 7m deep excavation by up to 3m to improve access to the damage. It is working for water company United Utilities.
A United Utilities spokesman said engineers will not know what caused the collapse until they can fully access the pipe but believe its age could be to blame.