RISKS of pollution to a scientifically important stream are among objections raised by councillors trying to halt a proposed quarry expansion.

Planners have been urged to reject the bid to increase the size of Stowe Hill quarry, on the grounds that ‘additional information’ supplied by owners Breedon Aggregates “fails to answer many of the questions asked”.

The proposal would also see the mineral processing plant relocated from Clearwell quarry to Stowe Hill.

But Newland Parish Council say Slade Brook near St Briavels – a Site of Special Scientific Interest with limestone dams – could still suffer pollution, and have written to Gloucestershire County Council’s planning department calling for the expansion plans to be rejected.

Protestors say Stowe Hill Quarry will be expanded by 153 acres, with extraction growing by a third to 800,000 tons per day.

They claim there would be more than 400 HGV movements per day, one every one minute 48 seconds through Coleford for 11 hours a day, five-and-a-half days a week, plus 25 lorries per day through Lydney and 21 through St Briavels.

And in a new submission to the county council, parish council clerk Richard Crighton says that despite slight changes to the scope of the plan, pollution would still “pose a real risk” to Slade Brook.

He adds: “Insufficient evidence has been provided to suggest quarrying in the extension area will not cause irreversible damage to, or increasing destruction of, this unique natural hydrogeological feature – the longest length of actively forming tufa [limestone] dams in Britain.”

The clerk says the council remains firmly opposed to the increased output to 800,000 tons per year from 600,000 and the associated increase in HGVs on roads

It also claims that in its submission to planners, Breedon Aggregates had failed to address calls for a 250m buffer zone from all residential homes, concerns over 11m high bunds or replacing the existing processing plant and primary crusher, “which cause great nuisance by way of noise and dust”.

“All the serious objections” on air quality and noise grounds had been ignored, despite formal allegations of breaches of conditions at the site nearly quadrupling to 50 in 2015, it adds.

And the statement continues: “Despite it being acknowledged that dust travels over 1km and will affect Clearwell and Sling, Breedon’s state that the “potential exposure … was determined to be not significant”. On what grounds is that statement based?”

Regarding the effect on the landscape, it claims that the developer’s submission “takes no account of the utter devastation during the 20-plus years between quarrying and full restoration”, and ignores the impact of HGVs on the B4228, one of the two major routes into the Forest.

As part of the plan, all the equipment, offices, and weighbridge would be moved from Clearwell quarry to Stowe Hill, with the construction of a new haul road from the latter to the B4228 at The Bearse (between Trow Green and St Briavels).

The council has previously protested that the floor of Stowe Hill quarry will have to be excavated down a further six metres over four years to take the equipment, leaving residents to suffer noise, dust, vibration and filthy roads.