galmoy mines ltd. · 2013-04-18 · galmoy mines ltd. wetland pollutant removal mechanisms and...
TRANSCRIPT
Galmoy Mines Ltd.
Attachment No C.1.
Wetlands trial
Based on a preliminary assimilative capacity assessment, directly discharging surface water to
the River Glasha, concentrations of most metals meet and exceed the standard required under
the current discharge licence to the River Goul and the WFD requirements as set out in S.I. No.
272/2009 — European Communities Environmental Objectives (Surface Waters) Regulations
2009. Concentrations of Lead, Zinc and Arsenic meet the requirements of SI 272, 2009.
The main function of the wetlands will be in reducing the concentrations of ammonical nitrogen
and BOD. Average concentrations of ammonium since May 2012 were 18.9 mg/l with higher
concentrations corresponding to periods of lower flows. Ammonium concentrations decreased
notably, in June 2012, Oct - Feb 2013 while concentrations were above 50 mg/l on average in
March-April and in July-August. Where flow and water quality data is available for the same day
the average ammonium concentration is 7.4 mg/l.
The source of the ammonium is the organic material used to cap the TMF. While ammonium is a
breakdown product of cyanide (a common reagent in sulphide ore processing plants), sodium
cyanide has never been used in the mine and so cyanide/ammonium does not present itself in
the tailings or the tailings water. Pore water testing of the organic material indicates that
ammonium concentrations in the organic material are elevated. Concentrations in the pore
water in two piezometers are on average 420mg/l and 552 mg/l in the Golders TMF report
(2011). High ammonium is therefore a function of the degradation of the organic material..
In summary, the nature of the capping material leads to a reducing environment that
contributes to the high ammonia levels in the runoff. Risk of pollution from the tailings and
shallow subsurface is low as the facility is lined with HDPE, the impermeability and depth of the
tailings deposits.
Ammonia/ammonium N (NH3 /NH4)
Ammonia is a common source of fertilizers as (1) anhydrous ammonia directly injected into the
soil and (2) ammonium salts such as ammonium nitrate or ammonium sulfate. Ammonium
fertilizer applied to aerobic soils is rapidly oxidized to nitrate. From these considerations, the
objectives of wastewater treatment are to oxidize ammonia to nitrate to reduce its toxicity and
deoxygenation effects. It is proposed to limit the quantity of Ammonium applied to the TMF cap,
thereby reducing the ammonium loading on the wetlands area.
Wetlands treatment options
Constructed wetland treatment systems are engineered systems that have been designed and
constructed to utilize the natural processes involving wetland vegetation, soils, and their
associated microbial assemblages to assist in treating wastewater. They are designed to take an
advantage of many of the same processes that occur in natural wetlands, but do so within a
more controlled environment. Constructed wetlands consist of former terrestrial environment
that have been modified to create poorly drained soils and wetlands flora and fauna for the
primary purpose of contaminant or pollution removal from wastewater. Constructed wetlands
are essentially wastewater treatment systems and are designed and operated as such, though
many systems do support other functional values.
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Galmoy Mines Ltd.
A major part of the treatment process for degradation of organics is attributed to the
microorganisms living on and around the plant root systems. Once microorganisms are
established on aquatic plant roots, they form a symbiotic relationship in most cases with the
higher plants. This relationship normally produces a synergistic effect resulting in increased
degradation rates and removal of organic compounds from the wastewater surrounding the
plant root systems. Also, microorganisms can use some or all metabolites released through
plant roots as a food source. By each using the others waste products, this allows a reaction to
be sustained in favor of rapid removal of organics from wastewater.
Nitrogen has a complex cycle with multiple biotic and abiotic transformations. The compounds
include a variety of inorganic and organic nitrogen forms that are essential for all biological life.
A series of biochemical and physico-chemical processes are involved in transforming one source
of N to another source. The most important forms of inorganic N compounds include ammonium
(NH4+), nitrite (NO2-), nitrate. The most important conversion processes functioning in the
wetland system are:
• nitrification
• denitrification
• biological fixation/uptake
• anaerobic ammonia oxidation and
• volatilization
Ammonia volatilization losses of NH3 from water and sediments are insignificant if the pH value
is below 7.5 and very often losses are not serious if the pH is below 8.5. At a pH value of 8.0
approximately 95% of the ammonia nitrogen is in the form of NH4. Therefore this process will
not be significant to the removal of ammonium.
A trial was undertaken in 2009 by VESI Environmental Ltd. to test the uptake of nutrients and
metals by a wetland system. The results are included in Wetlands trial and summarized below:
Parameter Removal rates
% Removal
Lead 91%
Zinc 92%
Sulphate 80%
Total ammonia 98%
Potassium 99%
BOD 79%
COD
97%
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Galmoy Mines Ltd.
Removal rates are conservatively assumed a maximum of 98% removal efficiency for
ammonium and 80% BOD will occur in the wetland area and a removal rate of 50% for metals
and sulphate.
Parameter Removal rates
% Removal
Lead 50%
Zinc 50%
Sulphate 50%
Total ammonia 98%
Arsenic 50%
BOD 80%
COD
50%
Given the low loading rates in the proposed wetland system the above removal rates can easily
be achieved. Similar and higher rates have been achieved in wetland systems in Ireland at
Glaslough20 and in wetlands treating tailings facilities and metals in motorway runoff21. The
proposed Hydraulic Retention times in the wetland area are very high at 4 litre/m2/day,
therefore the removal rates can easily be achieved. Details of the biotic and abiotic processes
involved in wetlands are highlighted in the Table below.
20
Glaslough ICW
http://www.dublincity.ie/WaterWasteEnvironment/WasteWater/Documents/Glaslough_ICW__Dan_Doody_et_al_-
_Feb_09__.pdf 21
Kadlec, R.H. and Knight, R.L (1996). Treatment Wetlands
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Galmoy Mines Ltd.
Wetland Pollutant Removal Mechanisms and their Major Controlling Factors22
Pollutant Removal
Mechanism
Pollutant Major Controlling Factors
Sedimentation Solids, BOD/COD,
Bacteria/pathogens,
Heavy metals, P,
Synthetic organics
Low turbulence; Residence time; emergent
plants
Adsorption
Heavy metals, Dissolved
nutrients,
Synthetic organics
Iron and Manganese Oxide particles; high
organic carbon; neutral to
alkaline pH
Biofiltration and
microbial
decomposition
BOD/COD, P,
Hydrocarbons, Synthetic
organics
Filter media; dense herbaceous plants; high
plant surface area; organic
carbon; dissolved oxygen; microbial populations
Plant uptake and
metabolism
P, N, Heavy metals,
Hydrocarbons
Large biomass with high plant activity and
surface area; extensive root
system
Chemical precipitation
Dissolved nutrients,
heavy metals
High alkalinity and pH
Ion exchange Dissolved nutrients High soil
cation exchange capacity e.g clay
Oxidation COD, Hydrocarbons,
Synthetic organics
Aerobic conditions
Photolysis As oxidation Good light conditions
Volatilisation and
aerosol
formation
Volatile hydrocarbons,
Synthetic
organics
High temperatures and wind speeds
Natural die-off
Bacteria/pathogens Plant excretion of phytotoxins
Nitrification NH3-N DO > 2 mg/l; Low toxicants;
Neutral pH; Temperature > 5-7 degrees
C; relevant bacteria
Denitrification NO3-N, NO2-N Anaerobicity; Low toxicants; Temperature >15
degrees C; relevant
bacteria
Reduction
Sulphate (resultant
sulphide can
precipitate metal
sulphides)
Anaerobic (anoxic) zone in substrate; relevant
bacteria
Infiltration Dissolved species
(nutrients, heavy
metals, synthetic
organics)
Permeable base and underlying soils
22 EA UK, 2003 Guidance Manual for Constructed Wetlands
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Galmoy Mines
Trial Wetland Project
12 October 2009.
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Galmoy Mines trial wetland project October 2009
2
Introduct ion
A trial wetland was developed between May and August 2009 to assess the effectiveness of a
wetland system for the treatment of mine drainage. Two wetland cells were set up within an
existing trial compound to monitor their performance and assess the possible use of an
Integrated Constructed Wetland at Galmoy Mines. The two wetland cells were set up for the
treatment of
(1) Spillway water and runoff from trial tailings pond (WC1)
(2) Precipitation generated runoff from the trail tailings pond (WC2).
Tria l wet land set up
Two wetland cells (36m2 each) were set up using an existing double liner (1.5mm and 0.75mm
liners) overlain with a geo-textile cover, with a depth 2.5 m of tailings over the liner. Earthen
embankments were constructed using imported clay material to divide the two trial areas. A
0.3m layer of subsoil material, with a 0.05m layer of top-soil was placed over the tailings in WC1.
A 0.3m layer of organic material was placed in WC2. Pipe work was placed at the base of the
cells at inlet and outlet points for WC1 and at the outlet point for WC2.
Figure 1. Trial wetland layout
Loading rates
Wetland Cell 1 received 0.15m3/day of spillway waters from tailing ponds and intercepting
rainfall. Wetland Cell 2 received intercepting rainfall only.
Rainfall during the monitoring period was above average. The table below shows the rainfall
during the monitoring period at Birr weather station c. 40km from Galmoy.
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Galmoy Mines trial wetland project October 2009
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Table 1 Rainfal l in mm 2009 and mean rainfa l l –Bir r weather stat ion
Month 2009 mm Mean cm
June 67.8 55.2
July 134.8 59.1
August 98.2 77.6
Plant ing
Each wetland cell was planted with a selection of three wetland species at a density of 10
plants/m2, 360 plants per cell. The species included Glyceria maxima (main species) and Carex
riparia, Cladium mariscus and Alisma plantago-aquatica.
Tria l period and monitoring
The trial period ran for 15 weeks. There was a period of two weeks at the start of the trial to
establish the system after planting. Monitoring was initially to be undertaken initially over a 10-
week period, with samples taken once every week. However monitoring proceeded over a
longer period in order to obtain additional monitoring results. A total of 8 water samples were
taken from the trial wetland during the 15-week trial period. Sampling was undertaken on the
influent to WC1 and effluent from WC1. No samples were taken from WC2 as there was no
discharge from this cell during the monitoring period. The parameters analysed included, pH,
Conductivity, Lead, Zinc, Nitrate, Nitrite, Sulphate, Sulphide, Ammonia, Ortho-phosphate,
Potassium and BOD. The volume of effluent discharging from the wetland cells was measured
when samples of the effluent were taken for analysis. Volumes of the effluent were between 0.25
litres and 1.0 litres.
Results
Results were only obtained from analysing samples taken from WC1, which received
0.15m3/day of spillway waters and intercepting rainfall. The range of influent concentrations
discharged to WC 1 is given in the table below.
Table 2 Inf luent concentrat ion range.
Parameter Max Min
Lead 275 µg/l 23 µg/l
Zinc 668µg/l 74 µg/l
Sulphate 595 mg/l 6 mg/l
Total ammonia 3074mg/l 97.6 mg/l
Potassium 421 mg/l 226 mg/l
BOD 130 mg/l 59 mg/l
COD 6600 mg/l 600 mg/l
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Galmoy Mines trial wetland project October 2009
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The range of effluent concentrations from WC1 is given in table 3 below.
Table 3 Ef f luent concentrat ion range.
Parameter Max Min
Lead 26 µg/l 5 µg/l
Zinc 27 µg/l <10 µg/l
Sulphate 195 mg/l 4 mg/l
Total ammonia 36.6 mg/l 0.61 mg/l
Potassium 2.88 mg/l 1.16 mg/l
BOD 50 mg/l 5 mg/l
COD 126 mg/l 44 mg/l
Volumes
The volume of effluent discharging from the WC1 was greatly reduced with the largest discharge
rate of 1litre recorded. This equates to 99.4% removal through evapotranspiration, with greater
rates of hydraulic reduction when accounting for intercepting rainfall. There was no discharge
from WC2, which removed intercepting rainfall through evapotranspiration. Hydraulic reduction
within the wetland cells is similar to what occurs in many ICWs in Ireland during the summer
period. During the trial period there was little or no surface water within WC1 and WC2. As the
wetland cells were lined, hydraulic losses can only have been through surface discharge
(minimal) and evapotranspiration. This has shown to be a good example of the rate of
evapotranspiration within a wetland.
Plants
Plant establishment within both wetland cells was very high. The pictures below show how the
plants colonized the trial area during the monitoring period.
Figure 2. Wetland Cell 2 after planting May 2009
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Galmoy Mines trial wetland project October 2009
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Figure 3. Wetland Cell 1 September 2009.
Removal ef f ic iency
When taking the mean influent and effluent concentration for the various parameters between 5
June 2009 and 27 August 2009 a high rate of removal was observed for lead, zinc, sulphate,
ammonia, potassium, BOD and COD.
Table 4 Removal rates
Parameter % Remova l
Lead 91%
Zinc 92%
Sulphate 80%
Total ammonia 98%
Potassium 99%
BOD 79%
COD 97%
Processes of metal removal
Metals can occur in either soluble or particulate associated forms. Metals such as Zinc have
shown to have a stronger affinity for the dissolved phase with Lead being particulate associated
(Cooper et. al. 1996). The table below shows the main processes of metal removal.
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Galmoy Mines trial wetland project October 2009
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Table 5 Processes of metal removal
Medium Processes
Vegetation Ion uptake/translocation
Adsorption
Organic decomposition
Filtration
Water Evaporation
Dilution
Complex formation
Decomposition
Microbial oxidation/reduction
Precipitation
Substrate Microbial oxidation/reduction
Ion exchange
Precipitation
Adsorption
Chelation
Chemical (organic) decomposition
Cation exchange capacity is the measure of ability of a substrate to adsorb positively changed
ions (such as metal ions) by exchanging them for other ions bound to the molecular structure of
the substance. The process requires continuous supply of fresh organic matter (produced by the
plants - detritus). Studies have shown (including Galmoy trial wetland project) that plants can
colonize heavily metal polluted areas. The plants as well as providing organic material for
adsorption of metals also absorb a wide range of metals, thus providing an important role in the
removal process. Bacteria and other micro-organisms facilitate the removal of metals by direct
accumulation of metals into their body structure.
Previous studies
International trials on constructed wetlands treating mine drainage have shown varying rates of
metal removal.
Table 6. Previous studies cit ing meta l removal rates
Source Lead removal Zinc removal
Nelson, E. A, et. al. 2005 83% 60%
Song, Y., et. al. 1992 90% 72%
Crites R. W., et. al. 98% 96%
Walton D. J., et. al. 2001 71% 57%
Galmoy trial wetland 91% 92%
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Galmoy Mines trial wetland project October 2009
7
Use of an ICW for the removal of metals at Galmoy Mines
At present consideration is being given to the use of a 5ha ICW at Galmoy. The ICW is to be
located to the west of the tailing ponds on relatively flat ground, which could provide c.
40,000m2 of surface water area. Based on an intercepting area of c. 22ha the ICW could receive
on average c. 500m3/day of runoff from the preceding tailing ponds (caped with glacial till) prior
to discharging to a proposed attenuation pond and the receiving surface water. Based on a
hydraulic loading of 500m3/day a 4ha ICW facilitate a nominal residence time of 24 days.
A laboratory scale wetland as cited in Song et al. recorded a lead removal rate of 90% based on
influent lead concentration of between 235 -90 µg/l. Hydraulic loading rates to the laboratory
scaled wetland was between 29 – 106l/m2/day. Based on similar lead concentrations, as
recorded from the trial wetland (275 – 23 µg/l) and a mean hydraulic loading of 12.5l/m2/day
(500m3 over 40,000m2) a high rate of lead removal, similar to the trial wetland is expected for the
proposed ICW system. Removal of zinc, sulphate and ammonia is also expected to be high
based on previous studies and monitoring of the trial wetland.
The development of an ICW for the treatment of mine drainage at Galmoy Mines would involve a
detailed design proposal, further examining the effectiveness of wetlands and assessing the
potential efficiency of the proposed ICW. The use of an ICW should involve an appropriate
operation and monitoring plan to ensure its successful functioning and continued performance.
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Galmoy Mines Ltd.
Attachment No D.1.1. Appropriate Assessment Screening Report
Aquens Report
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Galmoy MinesLtd
Proposed Surface water discharge from the rehabilitated Tailings Management Facility to the
River Glasha at Galmoy Mine
Appropriate Assessment Screening Statement
March2013
TOBIN CONSULTING ENGINEERS
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Appropriate Assessment Screening statement
PROJECT: Surface water discharge from the
rehabilitated Tailings Management
Facility to the River Glasha
CLIENT: Galmoy MinesLtd
COMPANY: TOBIN Consulting Engineers
Block 10-4 Blanchardstown Corporate Park
Dublin 15
www.tobin.ie
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Natura Impact Statement
DOCUMENT AMENDMENT RECORD
Client: Galmoy Mine Ltd
Project: Surface water discharge from the rehabilitated Tailings Management
Facility to the River Glasha
Title: Natura Impact Statement
PROJECT NUMBER:6811 DOCUMENT REF: AA Screening
Statement
A DRAFT RM 010313 JD 060313 DG 010313
Revision Description &
Rationale
Originated Date Checked Date Authorised Date
TOBIN Consulting Engineers
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Natura Impact Statement
i
TABLE OF CONTENTS
1 INTRODUCTION ........................................................................................................ 2
1.1 LEGISLATIVE CONTEXT ...................................................................................................... 3
1.2 GUIDANCE ............................................................................................................................ 3
2 METHODOLOGY ....................................................................................................... 5
3 SCREENING .............................................................................................................. 6
3.1 PRE SCREENING.................................................................................................................. 6
3.2 INFORMATION REQUIRED .................................................................................................. 6
3.3 IMPACT PREDICTION ALONE AND INCOMBINATION ...................................................... 12
4 SCREENING STATEMENT ..................................................................................... 13
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2
1 INTRODUCTION This report details an Appropriate Assessment Screening Statement for the proposed surface
water discharge from the rehabilitated Tailings Management Facility (TMF) at Galmoy Mines to
an offsite receiving stream. The TMF is undergoing rehabilitation and has reached an advanced
phase in this process.
As part of the rehabilitation plan, surface water runoff generated from the capped TMF will
discharge to the River Glasha at SW2. The main objectives for the rehabilitation of Phase 1 & 2
of the TMF are to achieve a sustainable, and stabilizing vegetative cover, install an engineered,
self draining cap and drainage system, establish agricultural grassland and biodiversity habitat,
long term beneficial agricultural use and establish a physically, chemically and biologically stable
and sustainable structure. The main objective for the rehabilitation of phase 3 are to achieve a
sustainable and stabilizing vegetation cover, to establish an integrated constructed wetland to
treat Phase 1 and Phase 2 runoff and provide a biodiversity habitat.
The integrated constructed wetland is a low waste sustainable treatment technology which can
adapt to conditions and deliver a high quality output. The integrated constructed wetland can
treat and reduce nitrate, ammonium, phosphate, BOD and metals thereby substantially reducing
the overall chemical loading on the River Erkina. Wetland trials in 2009 indicated the high
success rate of the wetlands area. Wetlands recovery and recycle nutrients that would otherwise
be discharge to the surface water network.
The proposed discharge point is a stream to the north of the site which links to the Glasha River,
which links into the River Erkina and then ultimately to the River Barrow and Nore SAC and River
Nore SPA.
This Appropriate Assessment Screening Statement has been informed by the following:
• Ecological Monitoring Report of the Glasha River which has been conducted yearly since
1995 (prior to the mines development) including the most recent report (Environmental
Monitoring of Rivers in the Galmoy Area (Report No. 17) Aquens Ltd December 2011)
• Tailings Management Facility Rehabilitation and Closure Plan (Golder Associates
January 2011),
• Report on the Assimilative Capacity of the River Glasha for the surface water discharge
from the TMF following passive treatment in a constructedwetland. (Tobin Consulting
Engineers February 2013 Report).
• Site survey (20th February 2013) to provide an updated baseline ecological assessment
of the receiving stream from the tailings ponds and downstream points monitored as part
of the Ecological Monitoring programme for the Glasha River.
The report considers potential adverse effects(“alone” - from the discharge and “in-combination” -
with other projects) onrelevant Natura 2000 requirements. The source of potential effect requiring
consideration is the water pollution risk of the discharge from the rehabilitated TMF
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3
This report determines if effects (of the discharge) are significant in the context of relevant Natura
2000 sites qualifying interests and their requirement for maintenance of a “favourable
conservation status”.
The report was drafted by an experienced trained ecologist (>17years experience) from TOBIN
Consulting Engineers with input from hydrologists/hydrogeologists (as required).
1.1 LEGISLATIVE CONTEXT
The Appropriate Assessment process (AA) is an assessment of the potential adverse or negative
effects of a plan or project, in combination with other plans or projects, on a European Site
(Natura 2000 site). These sites consist of Special Areas of Conservation (SACs) and Special
Protection Areas (SPAs) and provide for the protection and long-term survival of Europe’s most
valuable and threatened species and habitats.
The requirement of AA is outlined in Article 6(3) and 6(4) of the European Union Habitats
Directive.
Article 6(3) of the Habitats Directive requires that:-
“Any plan or project not directly connected with or necessary to themanagement of the site
but likely to have a significant effect thereon, either individually or in combination with other
plans or projects, shall be subject to appropriate assessment of its implications for the site
in view of the site's conservation objectives. In the light of the conclusions of the
assessment of the implications for the site and subject to the provisions of paragraph 4, the
competent national authorities shall agree to the plan or project only after having
ascertained that it will not adversely affect the integrity of the site concerned and, if
appropriate, after having obtained the opinion of the general public.”
And Article 6(4) of the Habitats Directive requires that:-
“If, in spite of a negative assessment of the implications for the site and in the absence of
alternative solutions, a plan or project must nevertheless be carried out for imperative
reasons of overriding public interest, including those of a social or economic nature, the
Member State shall take all compensatory measures necessary to ensure that the overall
coherence of Natura 2000 is protected. It shall inform the Commission of the compensatory
measures adopted.”
The EU HabitatsDirective was transposed into Irish law by the European Communities (Natural
Habitats) Regulations, SI 94/1997, recently amended by the Birds and Habitats Regulation SI No
477 of 2011.
1.2 GUIDANCE
This report has been carried out using the following guidance:
• Appropriate Assessment of Plans and Projects in Ireland, Guidance for Planning
Authorities, Department of the Environment, Heritage and Local Government DEHLG
(2009);
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• EPA Ireland guidelines1;
• Managing Natura 2000 Sites: the provisions of Article 6 of the ‘Habitats’ Directive
92/43/EEC, Office for Official Publications of the European Communities, Luxembourg
(EC 2000);
• Assessment of Plans and Projects Significantly Affecting Natura 2000 Sites:
Methodological guidance on the provisions of Article 6(3) and (4) of the Habitats Directive
92/43/EEC, Office for Official Publications of the European Communities, Luxembourg
(EC 2001); and
• Guidance document on Article 6(4) of the 'Habitats Directive' 92/43/EEC – Clarification of
the concepts of: alternative solutions, imperative reasons of overriding public interest,
compensatory measures, overall coherence, opinion of the commission. Office for Official
Publications of the European Communities, Luxembourg (EC 2007).
1http://www.epa.ie/downloads/forms/lic/wwda
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2 METHODOLOGY There are four main stagesin the AA process; the requirements for each depending on likely
effectsto Natura 2000 sites (SAC/ SPA).
Stage 1 –Screening-/ Test of Significance- the process which identifies the likely impacts upon
a Natura 2000 site of a project or plan, either alone or in combination with other projects or plans,
and considers whether these impacts are likely to be significantor if there is uncertainty regarding
effects;
Stage Two: Appropriate Assessment- the consideration of the impact of the project or plan on
the integrity of the Natura 2000 site, either alone or in combination with other projects or plans,
with respect to the site’s structure and function and its conservation objectives. Additionally,
where there are adverse impacts, an assessment of the potential mitigation of those impacts;
and mitigation to rule out these impacts is required.
The Appropriate Assessment is informed by a Natura Impact Statement (detailed herein). This
stage is required where uncertainty of effect or a potential impact has been defined which
requires further procedures/ mitigation to remove uncertainty or a defined impact.
Stage Three: Assessment of Alternative Solutions– the process which examines alternative
ways of achieving the objectives of the project or plan that avoid adverse impacts on the integrity
of the Natura 2000 site.
Stage Four: Assessment Where Adverse Impacts Remain- an assessment of compensatory
measures where, in the light of an assessment of Imperative Reasons of Overriding Public
Interest (IROPI), it is deemed that the project or plan should proceed.
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3 SCREENING
3.1 PRE SCREENING
An initial desktop “pre –screening” exercise was conducted to determine which Natura 2000 sites
are potentially relevant to the proposed discharge and hence if there is a potential for adverse
effects on Natura 2000 site(s). This was conducted utilising a standard SOURCE-RECEPTOR-
PATHWAY model, where, in order for an impact to be established all three elements of this
mechanism must be in place. The absence or removal of one of the elements of the mechanism
is sufficient to conclude that a potential effect is not of any relevance or significance.
Source –Discharge from the Rehabilitated Tailings Management Facility atGalmoy Mine;
Pathway – Direct discharge to the stream north of the site. The flow in the stream has been
impacted by mining activity due the lowering of the water table in the vicinity of the underground
workings. This stream is not a permanent water source and was dry in February 2013. This
stream eventually links into the Glasha River (permanent water source). The Glasha links into
the River Erkina which eventually links into the River Barrow and River Nore SAC and River Nore
SPA. The approximate distance of the discharge point to the River Barrow and Nore SAC is
13km. The approximate distance to the River Nore SPA is 16km.
Receptor - The River Barrow and Nore SAC qualifying interests, and related conservation
objectives, include water based qualifying interests which are potentiallyrelevant to any
discharges in the overall catchment.
On the basis of this pre-screening exercise for appropriate assessment it is determined that the
River Barrow and Nore SAC and River Nore SPA are relevant Natura 2000 sites requiring
consideration. In addition uncertainty regarding potential impacts (alone and in-combination) will
arise to theRiver Barrow and Nore SAC and River Nore SPA based on just this desktop
assessment. This is because the surface water discharge is a potential water pollution source
linked ultimately to downstreamNatura 2000 sites.
No other Natura 2000 sites are linked tomine discharge and hence can be screened out.
Further information is required to inform the AA Screening Statement before the assessment of
impacts can be concluded;
• Proposed pollution preventative measures in the rehabilitation plan
• Assimilative capacity of receiving waters and effects on downstream Natura 2000 sites
The process was progressed further as follows based on DEHLG (2009) guidelines.
3.2 INFORMATION REQUIRED
Description of the project or plan
Galmoy Mines Ltd is located within the townlands of Castletown, Whiteswall, Rathreagh,
Garrylaun and Rathpatrick close to the village of Galmoy in North County Kilkenny. The surface
facilities of the development are confined largely to the townland of Castletown on both sides of
the Johnstown/Rathdowney road, the R435.
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The TMFis located west of the R435. The TMF is managed as a water retaining structure. Ithas
been engineered with a double liner system (two HDPE layers). The footprint ofthe facility is
approximately 34Ha in three phases designed to store waste tails from the mining process. Each
phase has been progressively rehabilitated throughout the life of mine. Phase 1 has been
completely remediated, with Phase 2, 85% rehabilitated and Phase 3 currently used as
emergency storage of mine water and surface water from Phase 1 and Phase 2 of the TMF.
Following the completion of Phase 2 and Phase 3 rehabilitation, it is proposed to have a
permanent discharge to the River Glasha. The existing discharge (treated mine water and
treated process water)is to the River Goul.
As part of the on-going site closure, it is proposed that a wetland facility is constructed to treat
the surface water emanating from the rehabilitatedcap, with subsequent discharge of treated
effluent. The installation of the wetland in Phase 3 is designed to reduce the footprint of the TMF
and overall land take.
However, the treated runofffrom the surface of the rehabilitated cap contains primarily agricultural
runoff with some shorter term runoff from the interface between the cap which contains organic
matter (Phase 1 only)and the tailings. The final cap on Phase 2 is comprised of layer of compost
material and top soil. It is envisaged that the will be a significant improvement in the water quality
of the discharge emanating from Phase 2.
Available qualitative and quantitative data for the River Glasha, in conjunction with chemical
monitoring results of the TMFfrom Galmoy, form the basis for the assimilative capacity
calculations.
The water chemistry of the surface water discharge at the TMF taken from 2012 and 2013 show
the following:
• Ammonia concentrations are significantly elevated above normal background levels
ranging from <0.05 mg/l as N to 86mg/l as NH4. This is attributed to high ammonium
content in the organic layer used to stabilize the growing medium on the capping
layer. Low concentrations of Nitrate in the runoff indicate a low Total Nitrogen
loading.
• Phosphate levels are consistently low with all runoff containing <0.02 mg/l.
• Concentrations of trace metals are low in the runoff from the TMF. Lead
concentrations have consistently decreased and are currently <10 µg/l. However
some isolated spikes are noted.
• Elevated concentrations of arsenic were detected at the site. These levels are
attributed as aresult of reducing conditions and elevated levels of arsenic in the
tailings. The mobility of arsenic appears slightly elevated due to the presence of
organic material in the capping layer and reducing conditions
• Sulphate concentrations were elevated at various periods which coincided with
maintenance work on the final capping layer and drainage. Concentrations
decreased to <500 mg/l outside of the capping works.
Based on the preliminary assessmentof metal concentrations, directly discharging of
surfacerunoff water to the River Glasha,exceed the standard required under the current
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discharge licence to the River Goul and the WFD requirements as set out in S.I. No. 272/2009 —
European Communities Environmental Objectives (Surface Waters) Regulations 2009. The
Concentrations of Lead, Zinc and Arsenic recorded in the discharge water meet and exceed the
requirements of SI 272, 2009.
The main function of the wetlands will be in reducing the concentrations of ammonical nitrogen.
Average concentrations of ammonium in 2012 were 18.9 mg/l with higher concentrations
corresponding to periods whenrehabilitated cap maintenance was carried out in January-April
and July-August 2012. Ammonium concentrations decreased notably, in June 2012, Oct-Feb
2013 while concentrations were above 50 mg/l on average in March-April and in July-August.
The source of the ammonium is the organic material used to cap the tailings area. While
ammonium is commonly a breakdown product of cyanide at mining facilities (a common reagent
in sulphide ore processing plants), sodium cyanide has neverbeen used in the mill processing
circuits and so cyanide/ammonium does not present itself in the tailings or the tailings water.
Pore water testing of the organic material indicates that ammonium concentrations in the organic
material are elevated. Concentrations ofthe pore water in two compost piezometers are on
average 420mg/l and 552 mg/l in the Golder Associates Report (Jan 2011). High ammonium is
therefore a function of the degradation of the organic material in the cap.
In summary, the nature of the capping material leads to a reducing environment that contributes
to the high ammonia levels in the runoff. Risk of pollution from the tailings and shallow
subsurface is low, due to the impermeability and depth of the tailings deposits.
The discharge site is located within the catchment of the River Nore. The receiving stream for the
water discharge from the mineis not designated as a Natura 2000 site but eventually links to the
to the River Barrow and Nore SAC approximately 13km downstream and River Nore SPA
approximately 16km downstream.
Conservation objectives
Impacts to relevant Natura 2000 sites (River Barrow and Nore SAC and River Nore SPA) must
be considered in the context of qualifying interests described for the site. These are detailed as
follows.European and national legislation places a collective obligation on Ireland and its citizens
to maintain at favourable conservation status areas designated as candidates for Special Areas
of Conservation. The Government and its agencies are responsible for the implementation and
enforcement of regulations that will ensure the ecological integrity of these sites. According to the
EU Habitats Directive, favourable conservation status of a habitat is achieved when:
• its natural range, and area it covers within that range, is stable or increasing,
• the ecological factors that are necessary for its long-term maintenance exist and are
likely to continue to exist for the foreseeable future, and
• the conservation status of its typical species is favourable as defined below.
The favourable conservation status of a species is achieved when:
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• population data on the species concerned indicate that it is maintaining itself and the
natural range of the species is neither being reduced or likely to be reduced for
theforeseeable future, and
• There is, and will probably continue to be, a sufficiently large habitat to maintain its
populationson a long-term basis.
1. River Barrow and Nore SAC – Qualifying Interests
Qualifying Interests
* indicates a priority habitat under the Habitats Directive
• 1016 Desmoulin's whorl snail Vertigo moulinsiana
• 1029 Freshwater pearl mussel Margaritiferamargaritifera
• 1092 White‐clawed crayfish Austropotamobiuspallipes
• 1095 Sea lamprey Petromyzonmarinus
• 1096 Brook lamprey Lampetraplaneri
• 1099 River lamprey Lampetrafluviatilis
• 1103 Twaite shad Alosafallax
• 1106 Atlantic salmon (Salmosalar) (only in fresh water)
• 1130 Estuaries
• 1140 Mudflats and sandflats not covered by seawater at low tide
• 1310 Salicorniaand other annuals colonizing mud and sand
• 1330 Atlantic salt meadows (Glauco‐Puccinellietaliamaritimae)
• 1355 Otter Lutralutra
• 1410 Mediterranean salt meadows (Juncetaliamaritimi)
• 1421 Killarney fern Trichomanesspeciosum
• 1990 Nore freshwater pearl mussel Margaritiferadurrovensis
• 3260 Water courses of plain to montane levels with the Ranunculionfluitantisand
• Callitricho‐Batrachionvegetation
• 4030 European dry heaths
• 6430 Hydrophilous tall herb fringe communities of plains and of the montane to
• alpine levels
• 7220 * Petrifying springs with tufa formation (Cratoneurion)
• 91A0 Old sessile oak woods with Ilex and Blechnumin the British Isles
• 91E0 * Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno‐Padion,
• Alnionincanae, Salicionalbae)
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2. River Nore SPA – Qualifying Interest
Objective: To maintain or restore the favourable conservation condition of the bird species listed
as Special Conservation Interests for this SPA:
• Breeding Kingfisher (Alcedoatthis) [A229]
Relevant qualifying interests requiring consideration regarding the proposed discharge include
• 1092 White‐clawed crayfish Austropotamobiuspallipes
• 1095 Sea lamprey Petromyzonmarinus
• 1096 Brook lamprey Lampetraplaneri
• 1099 River lamprey Lampetrafluviatilis
• 1103 Twaite shad Alosafallax
• 1106 Atlantic salmon (Salmosalar) (only in fresh water)
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• 1990 Nore freshwater pearl mussel Margaritiferadurrovensis
In addition for kingfisher impacts to prey species (fish) require consideration
Ecological Assessment of Glasha River
An important aspect of the ecological assessment was to determine baseline qualifying interest
status in the vicinity of the downstream discharge.
To inform how sensitive these qualifying interests are a summary of key elements of information
studies are detailed which informed the screening statement.
The discharge stream north of the site currently is of no significant fishery or aquatic ecology
value as it is dry. No significant river is present until it joins the Glasha River.
Recent monitoring surveys of the Glasha did not confirm salmonids (though brown trout will likely
occur). The Glasha however is not a significant fishery. This is due to the overall moderate water
quality condition of the river, largely attributed to diffuse pollution from agriculture and its small
size. Additionally a number of physical modifications at Rathdowney prevent free passage of fish
upstream.
There is little suitable spawning or nursery habitat in the upper reaches of the river.
The site survey in February 2013 confirmed the presence of Otter (qualifying species for the
River Barrow and Nore SAC) and Moderate Water Quality (Q3 instead of Q3-4) compared to the
most recent ecological monitoring report (Aquens 2011) but in line with 2010 results derived from
the Macrophyte Index Scheme (see Table 1-1 below).
It is possible that the reduction in clean water discharge from the mine has resulted in a slight
decrease in Q values. In compliance with IPPCL, Galmoy Mines were required to augment the
local stream with clean water segregated underground to mitigate against the effects of
dewatering in thearea.The segregation of clean water underground was found to be very difficult
and ceased in 2005. Treated water from the treated process pond was used toaugment the flow
to streams. This discharge ceasedin April2010 at the request of the Authorities as it was deemed
an unlicensed discharge.However the Q3 values are consistent with the aquatic Q values at
Glasha Cross Roads.
These findings suggest that qualifying interests in the Glasha River are relatively insignificant in
the context of the overall designated sites.
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Table 1-1 Occurrence of aquatic macrophytes and water quality classes derived from the Macrophyte
Index Scheme (Aquens, 2011).
Sensitivity Glasha
Grouping GAC
Group B Callitrichestagnalis _
Less
Sensitive
Forms
Fontinalisantipyretica _
Apiumnodiflorum +
Rorippa nasturtium - aq. +
Berula sp. +
Ranunculuspenicillatus _
Group C Lemnaspp. _
Tolerant
Forms
Sparganiumspp. _
Scirpuslacustris _
Myriophyllumspicatum _
Potamogetonnatans _
Group D
Most Tolerant
Form
Cladophoracf. glomerata D
Water
Quality
Class
May-September 2010 Q3
May-September 2009 Q3
May-September 2008 Q3
May -August 2007 Q3-4
May -August 2006 Q3-4
May -August 2005 Q3-4
May-August 2004 Q3-4
May-August 2003 Q3-4
July & August 2002 Q3-4
June & July 2001 Q3-4
May & July 2000 Q3-4
May & July 1999 Q3-4
May & July 1998 Q3-4
May & July 1997 Q3-4
May 1996 Q3-4
= + present, C - common, D - dominant. * - September values. Q5 =Good; Q4 =Fair; Q3 =Doubtful; Q2 =Poor; Q1 =Bad.
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Assimilative Capacity of Glasha River
The findings of the Assimilative Capacity reportis that there is sufficient assimilative capacity in
the Glasha River for discharge concentrates and potential pollutants and no significant risk of
adverse impact on the River Barrow and Nore SAC and Nore SPA.
The site nearest the aquatic based DesignatedConservation Area hydrologicallylinked to the
Glasha river is the River Barrow and River Nore SAC and River Nore SPA, the boundary of
which is over 13 km and 16km downstream respectively.In addition to the assimilative capacity
findings these distances further rule out any significant alone and in-combination impacts based
on the fact that any material from the tailings ponds will be completely diluted and likely
undetectable before it reaches the SAC/ SPA. No toxic and or other effects are likely even
immediately downstream of the discharge.
Design proposals in Rehabilitation Plan
A wetland trial was completed as part of the rehabilitation plan. This trial indicated significant
reductions of chemical species monitored including BOD, Ammonia (relevant to fish qualifying
interests) and Nitrate. An area has been identified for a permanent wetland to treat the proposed
TMF output before final discharge to an Attenuation pond and then into the stream north of the
site which links to the Glasha River.
These precautionary design approaches will be consulted further with the Environmental
Protection Agency to establish final placement of wetland and discharge criteria. These
approaches will reduce concentrations below acceptable limits at the discharge point. Further
natural dilution throughout the river catchment meansthese concentrations will not be significant
regarding Natura 2000 sites qualifying interests downstream.
3.3 IMPACT PREDICTION ALONE AND INCOMBINATION
Given the assimilative capacity findings, on-going monitoring, proposed rehabilitation works
(including a wetland treatment system), precautionary design mitigation and extensive distances
to downstream Natura 20000 sites; it is considered certain that no adverse effectswill arise to
relevant Natura 2000 sites from the proposed treated tailings discharge.
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4 SCREENING STATEMENT It is considered that no significant adverse effects will arise from the proposed surface water
discharge from the TMF at Galmoy Minesto the stream and that this development can be
screened out from further Appropriate Assessment.
In informing this screening statement it is an assumption that on-going monitoring and careful
design approaches to minimise risks to local surface and groundwater quality will be
implemented.
Signed off by:
Mr. Roger MacNaughton
Senior Ecologist
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