Reported rubble/spoil in the Little Mealagh River, large scale land clearing including intense rock breaking and clearing of an Oak woodland. Derreenkealig where the Little Mealagh River crosses the road.
Pollution of the Avoca River by mine water discharging from drainage adits of abandoned copper and sulphur mines at Avoca, Co. Wicklow, Ireland, is a long-recognised problem. In addition there is diffuse flow into the river. The river is severely affected by the mine water and is considered by the EPA to be the most severely polluted stretch of river in Ireland.
Many studies have taken place relating to the Avoca River and its remediation. Among these, the University of Newcastle, in connection with the Eastern Regional Fisheries Board, produced a report in July 2003 entitled Restoring the Avoca River.
The preferred option for remediation was active treatment. However this can only be applied to the point discharges and does not take into account the diffuse flow and contaminated river sediments which are also contaminating the river quality.
The Camp Dresser McKee Ltd (CDM) report on the feasibility of managing and remediating the former mine site at Avoca, Co. Wicklow was completed in December 2008 and recommends active treatment of the point discharges into the Avoca River as well as treating the principal (spoil piles) cause of the contamination.
This Feasibility study also recognizes the importance of the diffuse flow and contaminated sediments and provides solutions for these also.
This report can be downloaded as PDF files from the links below:
Feasibility Study for the Management and Remediation of the Avoca Mining Site (2008)
In addition to the remediation work, continued monitoring to ensure no significant change in conditions occurs on site without detection was being provided for by way of a specialised Environmental Monitoring service
Note: the monitoring reports are not published after 2019, so unclear if the monitoring in ongoing
To date, in excess of €5 million has been expended on remediation and monitoring costs at the site. Works undertaken include: the capping of open shafts; addressing the stability of the Dublin Rosslare railway line which passes through the site; regrading and capping the mine waste area at Tigroney West and constructing surface drains to divert the surface flow around or across the capped area into the river and vegetating the capped surface. A number of actions were also undertaken to preserve mining heritage features on the site, notably the complete rehabilitation of a pair of historic ore bins.
“An annual inspection of an underground tunnel, the 850 Adit, raised safety concerns about a section of the tunnel which passes under a local residential road in 2019. This necessitated emergency repairs to the Adit between January and June 2020 to ensure its stability.
The Department allocated €1.1m funding for Avoca in 2020 of which in excess of €900,000 has been spent to date on the recent safety work undertaken at the 850 Adit. Funding of €450,000 is expected to be allocated for 2021. This funding will further support the monitoring of the site and will be used to re-evaluate the 2008 Feasibility study as a first step in the process to reappraise the approach to managing and restoring the site.”
“In excess of €5 million has been expended on remediation and monitoring costs at the site. As well as the health and safety work, environmental monitoring of the site is undertaken to ensure no significant change in conditions occurs without detection. Department has allocated €450,000 in 2022 to further support the monitoring and maintenance of the Avoca mines and to re-evaluate the 2008 Feasibility study to reappraise the approach to managing and restoring the site.”
Under the AIE Regs to request details of
– the chair and members of the Project Board for the Avoca Mine Site in Wicklow – agendas/minutes of Project Board meetings for 2020 to current date – any reports generated by the Project Board in relation to the site from 2020 to current date – copies of any Monitoring Reports completed after “Avoca Monitoring Report Round 3 2019”
For reference the Project Board is mentioned by Minister here
Minerals Prospecting Licences Granted – The licensed minerals are abbreviated as follows: Base metals (Bm); Barytes (b); Gold, Ores of (g); Silver, Ores of (s); Platinum Group Elements, Ores of (PGE), Rare Earth Elements, Ores of (REE); Molybdenum, Ores of (Mo); Beryllium, Ores of (Be); Caesium, Ores of (Cs); Lithium, Ores of (Li); Niobium, Ores of (Nb); Rubidium, Ores of (Rb); Tantalum, Ores of (Ta); Tin, Ores of (Sn); Tungsten, Ores of (W); Manganese, Ores of (Mn); Cobalt, Ores of (Co); Iron, Ores of (Fe)
The mine produced lead and zinc concentrates derived from sulphide rich ore hosted in dolomitised limestone.
Acid generating tailings from processing of the ore were deposited using the sub-aqueous technique in a fully composite lined tailings management facility (TMF), which is located on a peat bog.
The TMF is the largest fully lined tailings storage facility in Europe
Surface water run-off that falls on the TMF is converged into an engineered attenuation pond through three spillways. On exiting the pond, the surface water flows along an open channel, through another attenuation pond and out through the Clogheen stream and finally entering the Drish River.
Within the public drinking water source protection area for Drumcliff springs which supplies Ennis
Hydromorphology (land reclamation)
Small point sources (DWWTS and farmyards)
One operational limestone quarry within the Shallee_010 sub-basin but it discharges under S4 licence to the Fergus_040 waterbody to the north
EPA licensed facility located beside the quarry (Licence no. P0771) which discharges to ground within the sub basin. There is no process water discharged, only surface water which is discharged to ground from settlement ponds. The discharge is licensed for suspended solids and pH.
Pressures indicated for Tyshe are agriculture and domestic wastewater
The elevated ammonia concentrations could also indicate the presence of farmyard point sources.
Six domestic wastewater systems with high – very high P impact potential along the north and south tributaries of the Tyshe
Agriculture and urban wastewater are listed as the significant pressures
New WWTP for Ardfert was installed in 2017
Dewatering at the Section 4 quarry
The quarry has a section 4 license and is being dewatered – approximately 2500 m3/d on average
Drinking water abstraction at Ardfert South comes under strain in dry summer
Nitrate concentrations are consistently high
Chloride concentrations are consistently high
Elevated nutrients, including orthophosphate, ammonium and nitrate, as well as sediment, are the significant issues
Hydromorphology The Tyshe River, falls within the Banna Drainage District. Kerry County Council has a statutory duty to maintain this Drainage District. The River Tyshe flows to the sea at Blackrock. The outfall at Blackrock is vulnerable to blockage from build-up of sand (Flood Risk Management Plan for the Tralee Bay-Feale River Basin, 2018). Sand and seaweed are excavated out of the channel opening. These works currently take place at least every two weeks, but this can be daily in the winter months. The annual cost of these works is estimated at approximately €150,000. The drainage systems back up when this outfall at Blackrock is not clear. Maintenance work is also carried out to keep tidal flaps, approx. 600m upstream of the outfall, functioning. Sluice gates are manually operated to close on high tides to prevent tide backing up on Tyshe River, once every few weeks (Flood Risk Management Plan for the Tralee Bay-Feale River Basin, 2018). As part of a national Preliminary Flood Risk Assessment, discontinuing the existing regime of removing silt and debris from the outfall at Blackrock is being explored