Galmoy Mines Ltd. · 2013-04-18 · Galmoy Mines Ltd. Wetland Pollutant Removal Mechanisms and...

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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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%

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

Galmoy Mines

Trial Wetland Project

12 October 2009.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51


3

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51


4

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51


5

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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51


6

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%

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51


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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

Galmoy Mines Ltd.

Attachment No D.1.1. Appropriate Assessment Screening Report

Aquens Report

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

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);

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

4

• 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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

5

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.

For in

spec

tion p

urpo

ses o

nly.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

6

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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

7

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

8

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:

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

9

• 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)

19

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)

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

10

• 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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

11

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 -August 2007 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 1996 Q3-4

= + present, C - common, D - dominant. * - September values. Q5 =Good; Q4 =Fair; Q3 =Doubtful; Q2 =Poor; Q1 =Bad.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

12

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.

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

13

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

For

insp

ectio

n pur

pose

s only

.

Conse

nt of

copy

right

owne

r req

uired

for a

ny ot

her u

se.

EPA Export 18-04-2013:23:23:51

Galmoy Mines Ltd. · 2013-04-18 · Galmoy Mines Ltd. Wetland Pollutant Removal Mechanisms and...

Documents

Transcript of Galmoy Mines Ltd. · 2013-04-18 · Galmoy Mines Ltd. Wetland Pollutant Removal Mechanisms and...