Dredging of Peel marina will resume in the spring.

But the Department of Infrastructure is staying close-lipped over where the potentially toxic material will be dumped.

A planning application is due be submitted later this year.

About 3,000 tonnes of silt enters the marina from the River Neb each year, containing traces of heavy metals and other contaminants, largely as a result of historical mining operations.

If dredging does not take place, the accumulation of silt threatens the closure of a number of berths within the marina, which was last dredged in 2015.

The department estimates that about 25,000 tonnes of dredged material will be dealt with in the operation beginning next year.

In 2015 some 10,000 tonnes of silt were dredged from the marina under the emergency powers of the Public Health Act.

The material was dumped in a temporary storage facility built at Rockmount off the Poortown Road.

A public accounts committee inquiry found the operation was ’mishandled’ and financial regulations were ’almost completely ignored’.

A Peel Marina project board was established in May 2017, chaired by Tim Baker MHK, member for the DoI with responsibility for ports.

A number of solutions have been considered during the intervening months, in partnership with the Department of Environment, Food and Agriculture.

These balance the need to maintain the marina with the cost to the public purse and government’s responsibilities to the marine ecosystem and the island’s commercial fishery.

A proposed scheme has now been agreed and specialist external consultants appointed.

Expressions of interest are being sought from contractors who are able to carry out the dredging and construct a temporary lagoon to remove the water from the dredged material.

Mr Baker said: ’The project board has considered a range of options to address this challenging issue.

’Plans are progressing well to begin removing silt next year, with an innovative solution which will address the issues of Peel Marina at the same time as providing wider environmental benefits.

’The proposed scheme has the support of the Council of Ministers and Treasury and we expect to be in a position to submit a planning application before the end of the year.

’I look forward to being able to share full details of exactly how the process will work in the near future.’

A DoI spokesman said: ’A firm solution is now in place to dispose of the silt dredged from Peel Marina, one which will provide wider environmental benefits.

’Details are, however, still in the process of being finalised.’

In 2015, the then infrastructure minister Phil Gawne said it was appropriate to use emergency provisions to deal with the silt as it could not be dumped at sea and there were no licensed facilities on-shore.

But public concerns over the Rockwood site centred on the spillage of silt from lorries onto the roads and the fact that planning permission was sought retrospectively.

A Tynwald scrunity committee concluded that the DoI was aware of the risk of silting in the marina as far back as 2002 and should have done something about it before it became critical.

It praised DEFA for responding to a critical situation.

And it called on the DoI to report to Tynwald with costed plans to replace the temporary storage facility at Rockmount by 2020.