Utility officials in London say they are working to remove a mass of solidified concrete as heavy as a blue whale that's clogging three sewers.

The "concreteberg" – think iceberg but made of concrete – is thought to be over 300 feet long and weigh 115 tons, said utility service Thames Water in a statement.

Traffic disruptions are expected near the area of the concrete mass, as workers use tools such as jackhammer pneumatic drills and high-pressure jets to chip away at the blockage.

"This is not the first time damage has been caused by people pouring concrete into our sewers but it’s certainly the worst we’ve seen," said Alex Saunders, operations manager with Thames Water, in a statement. "It’s very frustrating and takes a great amount of time and effort to resolve."

The process of removing the "concreteberg" is expected to cost hundreds of thousands of dollars, said Thames Water.

Saunders said blockages are typically caused by a combination of fat, oil and wet wipes, dubbed a "fatberg." In January, a "fatberg" measuring 210 feet was found blocking a sewer in a seaside town in England.

Because it's concrete, and it has set to the sewers' Victorian brickwork, workers must chip away to remove it all, said Saunders. The utility said it's investigating how the concrete ended up in the sewer.

"We’re now doing everything we can to deal with it as quickly as possible, making sure our customers don’t have to suffer because of this mindless abuse of our network," said Saunders.

Follow Brett Molina on Twitter: @brettmolina23.