Llwyneinion Acid Tar Lagoon - Tar Characterisation Works

Descriptions

Llwyneinion Acid Tar Lagoon is a former clay pit and brick works situated in the village of Rhosllannerchrugog near Wrexham in North Wales. The lagoon comprises approximately 94,000 tonnes of acid tar to a maximum depth of approximately 10 metres and occupying an area of 1.3 hectares. Water to a depth of 0.5 - 1.0 metres generally covers the acid tar. In addition 365 individual drums and drum clusters have been identified in the lagoon. The individual drums appear to be present at approximately 2.0 metres below surface level whilst the drum clusters may extend to the base of the lagoon. There is also approximately 7,500 tonnes of Fullers Earth to the immediate north west of the lagoon.Some investigations involving the removal of acid tar have been carried out over the years but due to access difficulties samples have only ever been taken at approximately 1-2m depth near to the edge of the lagoon. More recently the site has been investigated by Environment Agency Wales as a potential 'Special Site' as described in the Contaminated Land (Wales) Regulations 2006. However at present it is considered that the site does not meet the legal definition of contaminated land.Wrexham County Borough Council, as owners of the site, propose a detailed investigation of the acid tar and Fullers Earth, which will be split into four stages as follows:Stage 1: Detailed design of the works, giving consideration to site topography and access difficulties, ecological issues and health and safety of both site operatives and nearby residents; to be undertaken in conjunction with Wrexham County Borough Council.Stage 2: Intrusive investigation involving removal of acid tar samples from various locations within the lagoon and removal of Fullers Earth samples. Sampling shall extend as far as is reasonably practicable through full depth of material. Any site clearance and/or accommodation works necessary ahead of investigation works are included in this stage. Stage 3: Laboratory analysis and testing of material samples to enable a thorough review of suitable remediation techniques to be assessed.Stage 4: Production of a detailed remediation options appraisal.Additional Information:(a) Mineshafts: Nine mineshafts are recorded in the vicinity of the site of which three are situated below the lagoon. The condition of these shafts before disposal of the acid tar began is unknown and there are no records to suggest that they have been capped.(b) Ecology: The area around the lagoon is dominated by woodland. An ecological appraisal has revealed evidence of badgers, whilst the area contains habitat that could potentially support bats, Great Crested Newt, reptiles and breeding birds.