THE LISHEEN MINE. For inspection purposes only.

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1 . THE LSHEEN MNE Dr. Karen Creed, Office of Climate, Licensing & Resource Use EPA Headquarters PO Box 3000 Johnstown Castle Estate Co. Wexford 10" November 2009 Re: Review of F'C Licence POO88-02 Dear Dr. Creed, n our submission for the use of surface channels (submitted 28" May 2009) the following statement was made; 'Previous studies have shown that there is very limited connection to the aquifer from principle surface water systems'. Lisheen Mine retained Shane 0 Neil1 of OGE Hydrology to prepare a brief summary report to support this statement. The report details the various studies that have been carried out over the years at Lisheen Mine into the relationship between surface water and groundwater The original ES suggested that there may be losses from surface waters around Lisheen; however the subsequent studies, detailed in this attached document, established that any connection between surface and ground hydrology was extremely limited. f you would need to discuss this further please contact the undersigned. Yours sincerely, Technical Services Manager THE LSHEEN MNE Killoran Moyne Thurles Co. Tipperary reland Telephone +353 (0) Fax +353 (0) ANGLB AMERlCAN Part of the Anglo American plc Group

2 Mr. Stephen Wheston, Lisheen Mine Mope, Thurles, Co. Tipperary Dear Stephen, RE : n The Area Of The Lisheen Mine, Thurles, Co. Tipperary have set out below a review of the work undertaken since 1995 on the potential for bed losses from surface rivers crossing the cone of drawdown induced by the mining operation at Lisheen Mine. The principal reports are : 1. RPS Cairns Ltd. Environmental mpact Statement Steffen, Robertson and Kirsten (SRK) Hydrological nvestigation Of Drish And Rossestown Rivers. September 1996 (Lisheen Mine Report No. 24/96). 3. SRK Report No /2 (Lisheen Mine Report No. 24/96). 4. OGE. nvestigation nto Low Flows n Rossestown River, September October OGE. Survey of Rossestown River to Evaluate Bed Loss Potential and Range of Depth and Discharge. October OGE Hydrogeology Ltd Springfield, Coughlanstown West, Ballymore Eustace, Co. Kildare T: F MbO soneill@p;roundwaterene.ie Directors: S ONeill (Managing) 0 O'Neill Registered Office as above. Registered No VAT No U

3 _ Lisheen Mine Page 2 of 4 6. OGE. ES To Accompany Planning Application For Development Of Bog Zone Orebodies. October OGE. ES To Accompany Planning Application For Construction Of 55 mw Wind Turbine Farm. Leakage From Rivers SRK, in their original work prior to any dewatering had started, indicated that the lower reaches of the Rossestown River were likely to have sigruficant channel bed losses. This conclusion was based on a detailed survey of the riverbed along its length. The nature and depth of substrate was recorded in this survey. SRK found that the thickness of the overburden in the river increased upstream towards Templetuohy Bridge. The nature of the substrate in the upper reaches was interpreted to limit the hydraulic conductivity between the river and the underlying bedrock. As part of the ES for The Lisheen Mine a steady state drawdown extended model was developed showing the extent of likely regional drawdown in the area around the mine. SRK predicted that the drawdown impact on the Drish River would be minimal, but that the drawdown under the Rossestown could be sigruhcant. Augmentation of low flows in the Rossestown River, through mine discharge, was recommended. This was done as part of the operation of the mine. The predicted drawdown under the Rossestown River was predicted to be a maximum of 150m adjacent to the south-eastern edge of the Carrick Hil Borrow Area. t turned out to be 120m. The drawdown under the Rossestown discharge point at Templetuohy Bridge was predicted to be approximately 60m. t turned out to be less than 20m. OGE have carried out two updates of the original predictive model. These were produced in 2000 and n both the overall shape of the drawdown cone remains consistent with the SRK model. However, the predicted drawdowns underlying the Rossestown River in the OGE models were much less than those for the SRK model. The Rossestown River flows over the mine area and over the cone of depression, and thus the river flows over the area of greatest effect of dewatering. There has been a significant amount of work carried out on the impact of the mine discharge and the dewatering process on the Drish River and the Rossestown River since the submission of the original ES in 1995.

4 Lisheen Mine Page 3 of 4 There has been no impact on the Drish River in terms of bed leakage or losses. The maximum potential leakage from the Rossestown to the Mine workings via regional structural features is an estimated 25% to 35% of the river flow. Given that the maximum licensed discharge to the Rossestown is 20Ml/d, then the maximum potential leakage back to the Mine would be 5 Ml/d to 7 Ml/d. The table below summarises the actual measured river gains and losses for the Rossestown River. This was undertaken in October Summary Of Volumes Of Water Lost And Gained Along Each Reach Chainage From Chainage To Loss/Gain Over Reach Loss/Gain Over Linear Metre Of Reach WVd) (MVd/m) -2.13e &le e e e e e e-03 Net Loss Net Gain 3.69 Overall Net Change e e e me e e i.02e-03 Net Loss Net Gain 1.34 Overall Net Change 0.49 Leakage From Peat Soils and Bogs Downward vertical seepage through peaty soils and bogs is limited as the vertical and horizontal permeability decreases sigmficantly with depth in raised bogs. Permeabilities of the surface layer are of the order of lo+n/s, while permeabilities of the lower layers are of the order of magnitude lo-sm/s. These permeabilities are similar to those of clays or siltstones. Characteristically, raised bogs are underlain by a clay basal deposit. Typical permeabilities for the marl (lake deposit) materials that underlie raised bogs are of the order of 10-*0m/s. These permeabilities are similar to those of shale or unweathered igneous rocks. n purely practical terms, these values mean that, where this low

5 , Eisheen Mine Page 4 of 4 permeability clay layer is present, the raised bog is essentially sealed off from the underlying bedrock beneath them. The water level in such raised bogs represent the water table of the unconfined ground water in storage in the bog and is independent of water levels, flow velocities and directions in the bedrock aquifer underlying the bog system. Summa y While there are potential river bed losses of between 25% to 35% as the Rossestown crosses the cone of drawdown, there are also sigmficant gains of between 6% to 36%. The detailed study of the Rossestown River potential bed losses concluded that there was a net gain in the river flow as the river crossed the cone of drawdown. There are no bed losses as the surface water bodies cross peaty soils or bogland. The Lisheen Mine have been discharging to surface water courses since There have been no incidents of any negative impact to water volumes in any surface water course as consequence of the mine dewatering. There have been no incidents of any impact of surface waters on ground waters caused by leakage of surface waters to ground waters. Yours Sincerely Shane ONeill PGeo.