Application for amendment of an environmental authority ... · PDF fileTable 2-2 Macrophyte species recorded at each site (Ecosure, 2012) . 18 Table 2-3 Pairwise ANOSIM comparisons

APPEN

DIX F

APPENDIX F

BUCK REEF WEST EA AMENDMENT

BRISBANE | PERTH | PAPUA NEW GUINEA AQUATIC AND SUBTERRANEAN ECOLOGY

ASSESSMENT

V1.0

—

AUGUST 2017

© Hydrobiology Pty Ltd 2017

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T H I S C O M P A N Y I S R E G I S T E R E D F O R G S T .

S T R E E T R E G I S T E R E D P O S T A L C O N T A C T

27 / 43 Lang Parade

Auchenflower 4066

QUEENSLAND

c/- de Blonk Smith and

Young Accountants

GPO 119, Brisbane 4001

QUEENSLAND

PO Box 2151

Toowong 4066

QUEENSLAND

+61 (0)7 3721 0100 P

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DOCUMENT CONTROL INFORMATION

D A T E P R I N T E D J O B N U M B E R R E P O R T N U M B E R

11/08/2017 CGL1701 1.1

P R O J E C T T I T L E Buck Reef West EA Amendment

P R O J E C T M A N A G E R Simon Drummond

D O C U M E N T T I T L E Aquatic and Subterranean Ecology Assessment

F I L E N A M E CGL1701_Buck Reef West EA Amendment_V1.1

S T A T U S O R I G I N A T O R / S R E V I E W E D A U T H O R I S E D D A T E

Draft JC SD, JCU SD 30/06/2017

Final JC SD SD 10/08/2017

Final JC SD SD 11/08/2017

DISTRIBUTION

F I L E N A M E D E S C R I P T I O N I S S U E D T O I S S U E D B Y

CGL1701_Buck Reef West EA

Amendment_V0.1

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Amendment

P. Smith and B. Dillon J. Cutajar

CGL1701_R_Buck Reef West EA

Amendment_V1.0

Buck Reef West EA

Amendment


CGL1701_R_Buck Reef West EA

Amendment_V1.0

Buck Reef West EA

Amendment


Buck Reef West EA Amendment ● 4

Aquatic and Subterranean Ecology Assessment www.hydrobiology.biz

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contents

1. INTRODUCTION 7 1.1 Background 7

1.2 Proposed Works 9

1.3 Scope of Works 9

2. EXISTING ENVIRONMENT 10

2.1 Regional Setting 10

2.2 Climate 12

2.3 Environmental Values 12

2.4 Aquatic Ecology 13 2.4.1 Geomorphology 13 2.4.2 Groundwater Dependent Ecosystems 13 2.4.3 Surface Water Quality 17 2.4.4 Macrophytes 18 2.4.5 Macroinvertebrates 19 2.4.6 Fish 22 2.4.7 Reptiles 25

2.5 Subterranean Ecology 26 2.5.1 Stygofauna 26 2.5.2 Troglofauna 36

3. AQUATIC ECOLOGY IMPACT AND MITIGATION ASSESSMENT 41

3.1 Project Impacts 42 3.1.1 Loss of Catchment Area 42 3.1.2 Drainage Diversion 42 3.1.3 RO permeate and Mine Water Releases 43 3.1.4 1Brine Disposal 47 3.1.5 Groundwater Drawdowns 47 3.1.6 Dry Stack Tailings Seepage and Deposition 48 3.1.7 Waste Rock Dump Seepage 48 3.1.8 Spills and localised contamination 48

3.2 Mitigation Strategy 51

4. SUBTERRANEAN FAUNA IMPACT AND MITIGATION ASSESSMENT 53

4.1 Project Impacts 54 4.1.1 Mine Pit Excavation 54 4.1.2 Dewatering 54 4.1.3 Brine disposal 55 4.1.4 Dry Stack Tailings Seepage and Deposition 55 4.1.5 Waste Rock Sump Seepage 55 4.1.6 Spills and Localised Contamination 55

4.2 Mitigation Strategy 55

5. SUMMARY AND RECOMMENDATIONS 57

6. REFERENCES 60

APPENDIX A. FIVE YEAR PROJECT OVERVIEW

APPENDIX B. WATER MANAGEMENT LAYOUT



tables Table 2-1 REs along Elphinstone and Suhrs Creek ................................. 17 Table 2-2 Macrophyte species recorded at each site (Ecosure, 2012) . 18 Table 2-3 Pairwise ANOSIM comparisons of Bray-Curtis dissimilarities,

based on community composition ........................................................... 21 Table 2-4 Fish species and abundances recorded during the July and

November 2011 surveys (Ecosure 2012) .................................................. 23 Table 2-5 Fish assemblages recorded from the Burdekin River system

upstream of the Burdekin Falls Dam (Pusey et al. 2004; Pusey et al.

2006; Carter and Tait 2008). Species listed were not recorded by

Ecosure (2012) ............................................................................................. 24 Table 2-6. Stygofauna habitat requirements ........................................... 27 Table 2-7 Defined aquifers (Coffey, 2012) ................................................ 28 Table 2-8 Physicochemical results for the April 2017 stygofauna

surveys .......................................................................................................... 29 Table 2-9 Monitoring bore coordinates and details. Coordinates in GDA

94, UTM Zones 55 ........................................................................................ 30 Table 2-10 Stygofauna survey results, November 2011, May 2012 and

April 2017...................................................................................................... 35 Table 2-11 Troglofauna survey bores and monitoring results .............. 39 Table 3-1 Sediment dam spill probability and dilution ratios to

Elphinstone Creek (WRM, 2017) ................................................................ 45 Table 3-2 Sediment dam spill probability and dilution ratios to Sandy

Creek (WRM, 2017) ...................................................................................... 45 Table 3-3 Proposed discharge limits for RO permeate and mine waste

water discharges (SLR 2017a) .................................................................... 46 Table 3-4 Potential Impacts and proposed mitigation strategy. ........... 51 Table 4-1 Potential Impacts and proposed mitigation strategy. ........... 56

figures Figure 1-1 Locality map ................................................................................. 8 Figure 2-1 Abandoned mine/identified mineralisation in the

Ravenswood areas (JCU, 2015) .................................................................. 11 Figure 2-2 Historical (1887 to 2017) climate statistics recorded at the

Ravenswood Post Office (station#:033062) (BOM 2017). ...................... 12 Figure 2-3. Likely groundwater expressions along Elphinstone Creek

(source: JCU 2016). ...................................................................................... 14 Figure 2-4 Monthly rainfall recorded at the Ravenswood post office

(station# 33062) from 2013 to 2016 vs. mean monthly rainfall............ 14 Figure 2-5. Groundwater dependant ecosystems of the Ravenswood

area (BOM, 2012). ........................................................................................ 15 Figure 2-6 Ravenwood depth to shallow groundwater in dry season

2016 (BDH, 2016 in JCU, 2016) ................................................................... 16 Figure 2-7 Mean macroinvertebrate taxa richness, abundances, SIGNAL

2 and PET richness from Elphinstone Creek catchment grouped by

treatment, habitat and season. Dashed lines represent 20th and 80th

percentile WQOs for central Queensland (EHP, 2009). .......................... 20



Figure 2-8 nMDS ordination of community assemblages based on

macroinvertebrate species abundance within bed habitats, showing

sites grouped by creek, treatment and season. ...................................... 21 Figure 2-9 Pump and sieve setup .............................................................. 32 Figure 2-10 Stygofauna and troglofauna survey bores, 2016 and 2017

survey years ................................................................................................. 33 Figure 2-11 Regional geology (Coffey, 2012) ............................................ 37 Figure 2-12 Void/vuggs (left photo) and extensive fracture system (right

photo) present along the exposed wall of the Sarsfield pit (Coffey,

2012). ............................................................................................................. 38 Figure 2-13 Trap deployment down exploration bore (left photo) and

close-up of troglofauna trap (right photo) ............................................... 39 Figure 3-1 Estimated sulphate concentration in Sarsfield Pit – single

realisation (median climate conditions) (WRM, 2017) ............................ 48 Figure 3-2. BRWP predicted groundwater drawdowns (SLR, 2017b). .. 50



1. INTRODUCTION 1.1 BACKGROUND The existing Ravenswood gold mine lies adjacent to the historic mining town of Ravenswood, which is

located 150 km south-west of Townsville and 65 km east of Charters Towers (Figure 1-1). The current

Ravenswood mine has been in operation since 1987 and currently employs 280 full-time workers and

pays State Government royalties of approximately $7.5 million annually.

Resolute Mining Limited (ASX:RSG)(“Resolute”) is an ASX listed developer and operator of gold mines in

Australia and Africa with over 25 years’ continuous production. Resolute is one of the largest

Australian gold miners having produced in excess of 7Moz of gold from nine gold mines since 1989.

Resolute acquired Carpentaria Gold Pty Ltd (CGL) in 2004 and assumed operating control of the

Sarsfield open pit mine near Ravenswood. In 2009 Resolute developed the nearby Mt Wright

Underground Mine with open cut mining operations ceasing at the Sarsfield open cut mine due to

reducing gold price and increasing operational costs. Operations at the Mt Wright Underground mine

will cease in 2017. As a result Resolute has recently commenced a transition back to open pit mining

with the open pit operations at the Nolan’s East deposit having commenced in August 2016 and

approval to recommence mining at the Sarsfield pit granted in 2017 (operation under current EA

EPML00979013). In order to maintain the approved processing rate of 5 Mtpa of ore, Resolute are

seeking approval to commence mining at the Buck Reef West Project (BRWP) footprint through an EA

amendment. Together the project will see the eventual development of three open pits at Nolan’s

East, Sarsfield and the proposed BRWP, which all form part of the Ravenswood Expansion Project

(REP).



Figure 1-1 Locality map



1.2 PROPOSED WORKS The aim of the BRWP is to recommence mining at the decommissioned Buck Reef West mine site. The

BRWP involves the excavation of a new open pit and development of associated waste rock dumps.

The BRWP area has previously been subject to small-scale underground and open pit mining. The

BRWP is expected to contribute to the currently approved processing rate of approximately 5 Mtpa of

ore with a Life of Mine (LoM) of approximately 5 years. Combined with the Nolan’s East and SEP

components of the REP, the BRWP will extend the REP LoM up to 2029. The BRWP is set to produce a

higher grade of ore than other components of the REP.

The key elements of the BRWP include:

• Increase current open pit area due to BRWP mine workings;

• Use of existing and new infrastructure for the REP, including the Nolan’s Processing Facility, new Dry

Stack Tailings Storage Facility (DSTSF) and new RO Plant (Both part of the Sarsfield Expansion Project

(SEP));

• Waste rock dumps to the south of the BRW open pit to accommodate for extraction of waste

materials; and

• Construction of a noise bund to the north and east of the BRW open pit.

The five-year Project overview is shown in Appendix A.

1.3 SCOPE OF WORKS This report is based upon the following scope of work:

• A description of the aquatic and subterranean ecology of the BRWP and surrounds based upon:

Historical data prepared for the initial SEP EIS.

New data acquired by through the receiving environment monitoring program (REMP) that CGL

commissioned from James Cook University (JCU).

Interrogation of new datasets (e.g. stygofauna dataset) maintained by DSITI and DEHP since the

2014 supplementary EIS.

Data acquired by the stygofauna sampling undertaken by Hydrobiology in May 2016 and

stygofauna and troglofauna sampling undertaken in April 2017.

Information held by Hydrobiology based on their history at site and at analogous areas in North

Queensland.

Published literature and available consultant reports for the area.

• Impact assessment focusing on the aquatic and subterranean ecological values including detailed

management, mitigation and monitoring measures to protect identified values.



2. EXISTING ENVIRONMENT 2.1 REGIONAL SETTING The BRWP is located within the Burdekin River basin, on the inland side of the Leichardt Range. More

specifically the BRWP is within the Kirk River sub-catchment of the upper Burdekin River. The

topography varies from gently undulating plains adjacent to the Burdekin River to relatively steep

escarpments in the Leichardt Range. Elevations range from approximately 180 m AHD at the river to

over 300m AHD along the range. Relief within the mine area varies by approximately 15 to 20 m. The

original topography at the site prior to mining was dominated by rocky outcrop hills. These hills

formed regional topographic highs and coincide with several local catchment boundaries (JCU, 2015).

The operations area lies in a highly mineralised catchment, and the wider area including the down-

gradient receiving environment has been subject to mining activity since the mid-1800’s. Although

much of the historical mining was small-scale or artisanal in nature, it has left a legacy of sites

throughout CGL’s mining tenements and receiving environments (Figure 2-1).



Figure 2-1 Abandoned mine/identified mineralisation in the Ravenswood areas (JCU, 2015)



The main watercourse draining the BRWP is the semi-permanent to permanent south to south-

southwest flowing stream gazetted as Elphinstone Creek. Elphinstone Creek traverses the western

boundary of the mine site, joining the Burdekin River some 17 km distance downstream from BWR.

The main watercourse draining the BRWP is the semi-permanent to permanent south to south-

southwest flowing stream gazetted as Elphinstone Creek. Elphinstone Creek traverses the western

boundary of the mine site, joining the Burdekin River some 17 km (distance downstream from BWRP).

Elphinstone Creek is fed by numerous south-east and south-west trending streams including Barrabas

Creek, Four Mile Creek (which drains the Mt Wright underground mine) and Suhrs Creek, which

generally flow only during the wet season. Ecosure (2012) described the watercourses as ephemeral

(i.e. cease to flow for periods of time), however pools remain during dry season conditions with

groundwater expressions and seepage from Suhrs Creek Dam (to the north of the BRWP) into

Elphinstone Creek.

None of the watercourses relevant to the Project have any state or national conservation significance;

the nearest High Ecological Value (HEV) area (Iron Pot Springs) is approximately 58 river km south-east

of the Ravenswood Mine (DSITI, 2017). Iron pot springs feeds a tributary into the Burdekin River some

3.5 km off the Burdekin River The Great Barrier Reef Marine Park boundary is located approximately

250 river km downstream of the Ravenswood Mine. The Burdekin Falls Dam Footprint begins

approximately 50 river km downstream of Ravenswood Mine.

Current land use in the area is dominated by grazing activities and to a lesser extent mining. The other

predominant land use is broad-acre grazing of beef cattle and goats, while the township of

Ravenswood also drains into Elphinstone Creek. Most of the area is considered poorly suited to

cultivation, due to soils with low water holding capacity, low fertility and high erodibility, and extremes

of climatic dry/wet variation.

2.2 CLIMATE The Ravenswood is located in the dry tropics with a climate characterised by relatively hot wet

summers and mild winters. The wet seasons is between the months of December and March and

provides much of the annual rainfall for the region (Figure 2-2). Mean annual rainfall at the

Ravenswood Township is 680 mm, although this is highly variable with annual rainfall since 1887

ranging from 125 to 1391 mm (BOM, 2017).

Figure 2-2 Historical (1887 to 2017) climate statistics recorded at the Ravenswood Post Office (station#:033062) (BOM 2017).

2.3 ENVIRONMENTAL VALUES Based on the project location, the most appropriate environmental values (EVs) are those proposed

(DSITI 2017) for Kirk River (relevant to Elphinstone and Sandy Creeks) and the Upper Burdekin River

(above dam) (relevant to the eventual receiving environment, the Burdekin River at the confluence of



Elphinstone Creek. Both the Kirk River and Upper Burdekin River (above dam) included aquatic

ecosystem values. DSITI (2017) indicates the management intent/level of protection afforded to these

areas is to maintain/achieve the relevant water quality guideline (i.e. moderately disturbed systems).

The below aquatic ecological review relates to the Elphinstone Creek catchment as this is the direct

receiving environment for the BRWP. Upgrades to the approved stormwater management systems

are also planned for the SEP which includes both Elphinstone and Sandy Creek catchments.

Descriptions of the aquatic ecosystem values of Sandy Creek are detailed in Hydrobiology (2016);

however potential impacts to Sandy Creek as a result of the proposed stormwater management

upgrades are discussed in this report.

2.4 AQUATIC ECOLOGY

2.4.1 GEOMORPHOLOGY Suhrs and Elphinstone Creeks were described by Carter et al. (2012) as third and fourth order streams

respectively in the vicinity of the proposed works. They both consist of a low to moderately sinuous

channel that is partly confined by the valley margins. The closeness of valley margins has resulted in

considerable bedrock outcropping controlling lateral and vertical migration of the channel.

Both systems have undergone considerable alteration over time, although Carter et al. (2012)

suggested that they are currently in a recovery phase. Disturbances to the geomorphology have

included:

• Disturbance of riparian vegetation by historic mining activities, urban development, weed

infestation, livestock and feral animals;

• Disruption to flow and sediment conveyance resulting from the construction of Suhrs Creek dam;

and

• Increased sediment delivery to Elphinstone Creek and Suhrs Creek (upstream of the dam) resulting

from historic landuse activities (mining, agriculture).

Despite the disturbed nature of the systems, they were generally composed of robust stream forms

with low sensitivity to geomorphic change due to the regular appearance of bedrock in the bed and

banks. This was particularly the case in Elphinstone Creek. Regardless, reaches not confined by

bedrock still show some susceptibility to localised bed and bank instabilities.

Considerable volumes of sand exist in the bed of both Elphinstone and Suhrs Creeks as a result of

upstream gully erosion and overland runoff. A low-flow channel meanders through these deposits,

creating lateral and longitudinal sand bars. The majority of this sand is exposed, although in Suhrs

Creek and the reach of Elphinstone Creek upstream of Burdekin Falls Dam Road, vegetation

encroachment has occurred as a result of historical seepage from Suhrs Creek Dam.

2.4.2 GROUNDWATER DEPENDENT ECOSYSTEMS The instream habitat of Elphinstone Creek is characterised as having moderate potential for

groundwater interaction (i.e. surface expressions of groundwater) from the headwaters to the

confluence of Four Mile Creek (Figure 2-5) (BOM, 2012). Downstream of the confluence, instream

habitat is characterised as having high potential for groundwater interaction. The 2016 mapped

depths to groundwater (BDH, 2016 in JCU, 2016) confirm surface-groundwater interactions as

indicated along a small area of Elphinstone Creek adjacent to the proposed BRW pit (Figure 2-6). Due

to the presence of disconnected shallow pools (Figure 2-3) and associated poor water quality, the

persisting pools are considered to contain low aquatic habitat value.



Site SW076_SAR

Site SW067_SAR

SW035_SAR

Figure 2-3. Likely groundwater expressions along Elphinstone Creek (source: JCU 2016).

Due to the below average rainfall exhibited over the past 4 years (average of 180 mm less per year)

(Figure 2-4) it is likely that groundwater expression could occur along other areas of Elphinstone Creek

particularly yellow and green mapped polygons in Figure 2-6. JCU (2016) confirms that the 2016 year

contained limited streamflow and flushing of ephemeral drainage systems off the mine operations

sites, and lower than normal groundwater levels.

Figure 2-4 Monthly rainfall recorded at the Ravenswood post office (station# 33062) from 2013 to 2016 vs. mean monthly rainfall.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Mean 148 149 99.6 37.5 25.5 27.7 15.4 13.6 11.9 21.2 44.8 83.1

2016 65.8 106 56.8 6.8 0 54.8 82.8 22.8 46.9 19 51.2 31.4

2015 168 79.6 24.8 42.4 0 7 4.8 0.8 0.6 2.6 87.8 27.2

2014 64.2 130 20.8 51 4.8 0 26.8 14.4 0 14.8 12.8 116

2013 167 91.4 53 65.4 17.6 3.8 3.2 0 0 3.2 123 8.8

020406080

100120140160180

Ra

infa

ll (

mm

)

Mean 2016 2015 2014 2013



Figure 2-5. Groundwater dependant ecosystems of the Ravenswood area (BOM, 2012).

Elphinstone Creek

Sandy Creek



Figure 2-6 Ravenwood depth to shallow groundwater in dry season 2016 (BDH, 2016 in JCU, 2016)



Riparian vegetation along Elphinstone Creek is characterised by dry to moist eucalypt woodlands and

open forests, mainly on undulating to hilly terrain of mainly metamorphic and acid igneous rocks,

Land zones 11. Descriptions of identified regional ecosystems (REs) within the Elphinstone Creek

catchment are listed in Table 2-1. These REs have been described as having a low to moderate

potential for groundwater interactions (i.e. less likely to be reliant on groundwater) (BOM, 2012) and

are likely to be more reliant on rainfall as their primary water input. Additionally, Inflow dependence

mapping (IDE) (BOM, 2012), indicates that the Elphinstone Creek catchment contains inflow

dependence (ID) ratings largely between 5 and 3, further suggesting that these landscapes are more

likely to rely on rainfall as their primary water input. The riparian habitat across this sub-catchment

has been described as being very poor with declines due to large gaps in the riparian vegetation along

stream corridors, clearing around headwaters of streams and with very high levels of hillslope erosion

(83%) and gully erosion (15%) (Dight, 2009). Recent surveys have identified the presence of

widespread infestations of weeds terrestrially as well as within riparian and in-channel locations (JCU,

2016).

Table 2-1 REs along Elphinstone and Suhrs Creek

RE Location Description

9.3.1 Upstream and Downstream

Fringing woodland to open forest of Eucalyptus camaldulensis (river red gum) and/or E. tereticornis (bluegum) +/- Melaleuca fluviatilis (teatree) and/or M. leucadendra (weeping teatree) +/- Casuarina cunninghamiana (river sheoak) +/- Corymbia tessellaris (Moreton Bay ash). A distinct sub-canopy can occur and contain Ficus spp., Lophostemon spp. and Pleiogynium timorense (Burdekin plum) as well as juvenile canopy species. The shrub layer varies from none to mid-dense and contain Ficus opposita (sandpaper fig), Melaleuca spp. and Acacia crassicarpa (hickory wattle). The dense ground cover commonly includes Heteropogon contortus (black speargrass) and Themeda triandra (kangaroo grass) as well as a range of other graminoid and forb species. Occurs on stream and channel banks

9.12.1a Upstream Woodland to low open woodland of E. crebra (narrow-leaved ironbark) +/- Corymbia dallachiana (Dallachy's gum) +/- C. erythrophloia (red bloodwood) +/- C. clarksoniana (Clarkson's bloodwood) +/- Corymbia spp. E. exilipes (fine-leaved ironbark) or E. granitica (granite ironbark) can sometimes occur as a dominant. An open sub-canopy can occur with canopy species as well as Geijera salicifolia (wilga), Petalostigma pubescens (quinine), Denhamia cunninghamii (yellowberry bush), Bursaria incana (prickly pine) and Acacia spp. An open shrub layer usually includes canopy and sub-canopy species and Carissa lanceolata (currantbush). The sparse to dense ground layer is dominated by Heteropogon contortus (black speargrass) and Themeda triandra (kangaroo grass). Occurs on a variety of landforms from undulating plains to steep hills

2.4.3 SURFACE WATER QUALITY A significant observation from the initial REMP (JCU, 2016) is that the different ephemeral stream

systems exhibit very different surface water chemistry signatures. Elphinstone Creek to the north /

west of the Nolan’s operation area was characterised by a step change in condition on the northern

outskirts of Ravenswood, reflecting both water persistence and water quality. Below this ‘boundary’,

surface water pools and flows were sustained by groundwater expression throughout the year and

water quality was characterised by relatively uniform and elevated concentrations of arsenic,

molybdenum (and to a lesser extent uranium) compared with other stream systems. Based on

groundwater level and quality data, this signature does not derive from Carpentaria Gold operations

and is inferred to reflect regional groundwater conditions (JCU, 2016). Total aqueous metal

concentrations suggested there are indications of some level of mineralisation at some up-gradient



sites on Elphinstone, but this is not reflected in the sediment chemistry (JCU, 2016). Stream bed pore

water chemistry generally reflects the overlying surface water chemistry which is to be expected given

the porosity of the creek bed sediments.

Mt Wright differs from Nolan’s operations area in terms of both physical location and its position

within the drainage catchment (sitting on a local peak at the head of several small streams). Similarly,

water quality patterns in the Mt Wright drainage systems sits apart from those observed in the other

systems. Recent monitoring indicated that potential contaminants did not exceed defined

guidelines/triggers (JCU, 2016).

Further information relating to water quality of the BRW receiving environment, including defined

water quality criteria for the proposed BRW operations are provided within WRM (2017).

2.4.4 MACROPHYTES Ecosure (2012) surveyed macrophytes at a number of sites along Elphinstone and Suhrs Creeks.

Macrophytes were found to be sparse; however where recorded were dominated by emergent

species, particularly cumbungi and the exotic umbrella sedge. Field surveys identified 11 species

(Table 2-2).

Two introduced freshwater plant species (umbrella sedge and parrots feather) were identified;

however are no longer declared weeds under the Land Protection Act (pest and stock route

management) 2002.

CONSERVATION SIGNIFICANT SPECIES No nationally (Environmental Protection and Biodiversity Conservation Act 1999, EPBC Act) or state

(Nature Conservation Act 1992, NC Act) listed threatened (endangered, vulnerable, near threatened)

macrophytes were recorded or are likely to occur within the receiving environment or surrounds (10

km buffer).

Table 2-2 Macrophyte species recorded at each site (Ecosure, 2012)

Species Common name

Elphinstone Creek Suhrs Creek

Elp

h 1

Elp

h 2

Elp

h 3

Su

hrs

1

Su

hrs

Dam

Cyperus difformis dirty dora

Y

Cyperus involucratus umbrella sedge

Y Y

Typha orientalis cumbungi Y Y Y Y Y

Chara spp. stonewort

Y

Potamogeton crispus curly pondweed

Y

Cyperus polystachyus flat sedge Y

Y

c.f. Juncus sp. reed sp.1

Y

Bolboschoenus sp. clubrush sp.

Y Y



Species Common name


Elp

h 1

Elp

h 2

Elp

h 3

Su

hrs

1

Su

hrs

Dam

Persicaria decepiens slender knotweed

Y

Nymphoides indica water snowflake

Y

- filamentous algae Y Y Y Y Y

2.4.5 MACROINVERTEBRATES Monitoring data collected by JCU as part of the on-going REMP was used to define macroinvertebrate

assemblages within the concerned catchments. The JCU (2015) REMP design includes both spatial and

temporal variability with monitoring sites located upstream (control sites) and downstream (test sites)

of the mine footprint with sampling undertaken over three seasons (post wet, early dry and late dry).

At each site triplicate invertebrate samples are collected, with macroinvertebrates collected within

bed, edge and riffle/run habitats; however sampling in 2016 largely occurred within bed habitats.

For the purpose of this assessment, several assemblage indices were calculated to compare

invertebrate communities both spatially and temporally. This included the calculation of:

• Species richness (number of species);

• Abundance (number of individuals);

• Plecoptera, Ephemoptera, Trichoptera (PET) richness (number of more pollution sensitive species);

and

• Abundance weighted Stream Invertebrate Grade Number – Average Level (SIGNAL) biotic index (a

pollution scoring system for macroinvertebrates based on their pollution tolerances) (Chessman,

2003).

To provide a regional context for calculated assemblage indices, values were compared to the central

Queensland biological guidelines (20th and 80th percentiles) for macroinvertebrates (EHP, 2009).

Assemblage indices were also compared statistically via the use of a three-factor (creek, treatment,

season) nested Permutational ANOVA (PERMANOVA), with treatment nested within creeks. Significant

results (p<0.05) were followed by pairwise comparisons to identify primary drivers.

Non-metric Multi-Dimensional Scaling (nMDS) generated from Bray-Curtis similarity matrices were

used to graphically represent macroinvertebrate assemblages from different creeks, treatments and

seasons in a two-dimensional space. Pairwise comparisons for differences in macrofaunal

assemblages were also tested using the analysis of similarity (ANOSIM) test. Similarity percentage

(SIMPER) analyses were used to identify which taxa contributed to any observed dissimilarities in

community assemblages.

Before testing, all data were log (x+1) transformed to improve normality and reduce

heteroscedasticity. Due to the absence of riffle and run habitat at control sites, no such statistical tests

were carried out for these habitats.



DIVERSITY INDICES

Comparisons made with EHP (2009) biological WQOs for central Queensland indicated that mean taxa

and PET richness at all bed habitat sites (control and impact) were below defined 20th percentiles

(Figure 2-7). Mean signal 2 values at all bed impact sites either conformed to or were above defined

80th percentiles, indicating greater pollution sensitive taxa. In contrast, mean signal 2 values at bed

control sites were below defined 20th percentiles.

Univariate statistical analyses (PERMANOVA) indicated that macroinvertebrate bed habitat SIGNAL 2

scores differed significantly (p<0.05) among treatments, with Elphinstone Creek test sites exhibiting

significantly greater SIGNAL 2 score than control sites upstream of the mine footprint. Therefore,

downstream sites are considered to contain greater diversity and number of taxa which are

considered more pollution sensitive. No such significant spatial differences (p>0.05) were exhibited in

macroinvertebrate species richness, PET richness or abundances. Due to the absence of water, only

impact sites were sampled along Four Mile Creek, as such statistical comparisons between control and

impact sites could not be made.

Both SIGNAL 2 and macroinvertebrate abundances exhibited temporal variation, with significantly

greater (p<0.05) values noted during post-wet conditions than the early dry season.

Figure 2-7 Mean macroinvertebrate taxa richness, abundances, SIGNAL 2 and PET richness from Elphinstone Creek catchment grouped by

treatment, habitat and season. Dashed lines represent 20th and 80th percentile WQOs for central Queensland (EHP, 2009).

COMMUNITY ASSEMBLAGE Multivariate analyses (nMDS) of community assemblages separated Elphinstone Creek post wet and

Elphinstone Creek late dry from their respective seasonal control sites (Figure 2-8). ANOSIM tests

confirmed observed differences were significant (p<0.05) (Table 2-3), with the late dry season results

exhibiting the strongest dissimilarity (R=0.74, p=0.001).



Figure 2-8 nMDS ordination of community assemblages based on macroinvertebrate species abundance within bed habitats, showing sites

grouped by creek, treatment and season.

Table 2-3 Pairwise ANOSIM comparisons of Bray-Curtis dissimilarities, based on community composition

Group R statistic P value

Elphinstone Creek Tests post-wet vs. Elphinstone Creek Control post-wet

0.533 0.039

Elphinstone Creek Tests late dry vs. Elphinstone Creek Control late dry

0.74 0.001

Identified differences in community assemblages between Elphinstone Creek control and impact sites

are attributed to:

• Additional taxa (~ 90% contribution) noted at test site during the post wet season which include

Tanypodinae; Odonata; Caenidae; Hydrophilidae; Baetidae; Coenagrionidae; Ceratopogonidae;

Corixidae; and Oligochaeta. In contrast the Elphinstone control test sites were dominated (~90%

contribution) by three pollution tolerant taxa (Chironominae, Copepoda and Dytiscidae).

• Largely different macroinvertebrate communities during the late dry season with control sites

dominated by four taxa (Corixidae, Baetidae, Dytiscidae, Tanypodinae) and impact sites dominated

by six taxa (Chironominae, Caenidae, Tanypodinae, Odonata (HUL complex), Dytiscidae and

Tabanidae).



Taxa noted above at the control sites during post-wet conditions are considered to be more salt

tolerant (Dunlop et al. 2005); however electrical conductivity at control sites was considerably less

(between 100 and 150 µS/cm) than impact sites (1,200 µS/cm) (JCU, 2016). In contrast, late dry

conditions at both control and impact sites represent macroinvertebrate salinity tolerances over the

spectrum. Therefore, it is likely that noted differences in community assemblages represents available

habitat. During both seasonal surveys, control sites contained small residual pools with little substrate

variability (dominated by sands), no canopy cover and absence of macrophytes, leaf litter and snags.

In contrast habitat complexity at test sites was far greater with sites containing diverse substrates

(presence of boulders, cobbles, gravel, sands and fines), greater canopy cover and presence of

macrophytes, leaf litter and snags.

It should be noted that control sites along Elphinstone Creek have historically been subject to mining

activities and as such do not represent a pristine environment for which reference sites should be

selected; however they provide context of surrounding impacts that already exist within these

catchments.

AUSRIVAS CONDITION ASSESSMENT AUSRIVAS ecological modelling of Four Mile Creek indicated that habitat and/or water quality

condition at downstream monitoring sites improved with distance from the Mt Wright footprint, with

macroinvertebrate communities indicating significantly impaired (BAND B) to reference-like condition

(BAND A) (JCU, 2016). The impaired conditions were an artefact of available habitat at the time of

sampling (small recessional pool with decaying detritus and resultant high nutrients) rather than

anthropogenic impact (JCU, 2016). However, comparisons discussed in JCU (2016) are limited as they

have been made between sites where macroinvertebrates were collected from differing habitats.

AUSRIVAS condition scores, should only be compared with regard to similar habitat (i.e. compare edge

habitat results against other edge habitat results) as habitats can respond differently to impacting

processes. For instance, bed habitat would be more affected by depositing material than edge habitat.

Bed habitats along Elphinstone Creek indicated that habitat and/or water quality improved

downstream of the mine footprint with habitat/water quality conditions at impact sites more similar

to reference conditions (JCU, 2016), while control sites contained significantly impaired habitat/water

quality conditions. Additionally, AUSRIVAS condition scores along Elphinstone Creek indicated that

riffle habitat and/or water quality condition reduced from significantly impaired at the nearest

downstream site to severely impaired (BAND C) further downstream of the mine.

It should be noted that there are a number of limitations associated with the JCU (2016) analysis for

which AUSRIVAS is used to draw a number of conclusions regarding potential impact. For instance, the

methods used for collection and processing are not in accordance with the AUSRIVAS sampling

manual (DNRM, 2001). JCU (2016) employed field picking for only 15 minutes for each replicate. The

AUSRIVAS manual requires a minimum 30 minute pick, with additional time required where the target

number of individuals (200) has not been reached or where any new taxa are found. As the employed

methods are not consistent with DNRM (2001) any interpretation made in JCU (2016) regarding

AUSRIVAS ecological modelling could be invalid.

CONSERVATION SIGNIFICANT SPECIES There are no nationally (EPBC Act) or state (NC Act) listed threatened (endangered, vulnerable, near

threatened) macroinvertebrates recorded or likely to occur within the receiving environment or

surrounds.

2.4.6 FISH Ecosure (2012) surveyed fish at 5 sites along Elphinstone and Suhrs Creek in July and November 2011.

A list of species recorded by Ecosure are presented in Table 2-4. A total of 13 species were recorded



during the 2011 (July and November) EIS surveys. The most common native species recorded in

Elphinstone and Sandy Creeks was Melanotaenia splendida (Eastern rainbow fish) and Mogurnda

adspersa (purple-spotted gudgeon). A single exotic species (Oreochromis mossambicus) was recorded in

Elphinstone Creek. Tilapia represented on average 35% of recorded individuals and was widely

distributed. Recreationally significant species included Oxyleotris lineolatus (sleepy cod) and to a lesser

extent, Leiopotherapon unicolor (spangled perch), Hephaestus fuliginosus (sooty grunter), Neosilurus ater

(black catfish) and Neosilurus hyrtlii (Hyrtl’s tandan). It should be noted that sleepy cod have been

translocated into the upper Burdekin catchment as an angling species. Fish species recorded in the

study area are generally resilient species, tolerant of a wide range of conditions.

Table 2-4 Fish species and abundances recorded during the July and November 2011 surveys (Ecosure 2012)

Species Common name


Elp

h 1

Elp

h 2

Elp

h 3

Su

hrs

1

Su

hrs

D

am

July 2011

Ambassis agasizzii olive perchlet

1

9

Amniataba percoides barred grunter

6 52 11 20

Craterocephalus stercusmuscarum

fly-speckled hardyhead

7

Hephaestus fuliginosus sooty grunter

2 2

Hypseletros sp.1 Midgley's carp gudgeon

158

Leiopotherapon unicolor spangled perch

90 98 70

Melanotaenia splendida Eastern rainbow 9 63 201 322

Mogurnda adspersa purple-spotted gudgeon 78 64 37 163

Nematalosa erebi bony bream

4 108

21

Neosilurus ater Black tandan

1

Neosilurus hyrtlii Hyrtyl's tandan

3 16

Oreochromis mossambicus tilapia

238 842 121 20

Oxyeleotris lineolatus sleepy cod

3

19

November 2011

Ambassis agasizzii olive perchlet

Sit

e d

ry

81

Amniataba percoides barred grunter

26

Craterocephalus stercusmuscarum

fly-speckled hardyhead 4

Hephaestus fuliginosus sooty grunter 1



Species Common name


Elp

h 1

Elp

h 2

Elp

h 3

Su

hrs

1

Su

hrs

D

am

Hypseletros sp.1 Midgley's carp gudgeon

2 52

Leiopotherapon unicolor spangled perch 30 44 2

Melanotaenia splendida Eastern rainbow 97 20 267 106

Mogurnda adspersa purple-spotted gudgeon 35

199

Nematalosa erebi bony bream

31

1

Neosilurus hyrtlii Hyrtyl's tandan 1

Oreochromis mossambicus tilapia 62 84 61 16

Oxyeleotris lineolatus sleepy cod

1 1 2

Additionally, a total of 8 other native species not identified by Ecosure (2012) and a single exotic

species have been recorded in the Burdekin catchment upstream of the Burdekin Falls (Pusey et al.

2004; Carter and Tait 2008) (Table 2-5). Notably, Lates calcarifer (barramundi) and Macquaria ambigua

(yellow belly) have been recorded which are regarded to be significant recreational species. Recent

surveys undertaken as part of the REMP indicated the presence of five species (C. stercusmuscarum, M.

splendida, L. unicolor, O. mossambicus) at six downstream sites along Elphinstone Creek, though

abundances were not provided (JCU, 2016). No fish were recorded at upstream sites which contained

water. It should be noted that fish survey techniques were limited to visual observations due to the

presence of small shallow pools.

Table 2-5 Fish assemblages recorded from the Burdekin River system upstream of the Burdekin Falls Dam (Pusey et al. 2004; Pusey et al.

2006; Carter and Tait 2008). Species listed were not recorded by Ecosure (2012)

Species Common name Status

Gambusia holbrooki mosquito fish Exotic

Hypseleotris kluzingeri Western carp gudgeon Native/translocated

Lates calcarifer barramundi Native

Macquaria ambigua golden perch Translocated

Neosilurus mollespiculum

soft-spinned catfish Native

Philypnodon grandiceps flathead gudgeon Native/translocated

Porochilus rendahli Rendahl’s catfish Native

Scortum parviceps small-headed grunter Native

Tandanus tandanus eel-tailed catfish Translocated (established)



Species Common name Status

Toxotes chatereus seven spotted archerfish Native

CONSERVATION SIGNIFICANT SPECIES There are no nationally (EPBC Act) or state (NC Act) listed threatened (endangered, vulnerable, near

threatened) fish recorded or likely to occur within the receiving environment or surrounds.

2.4.7 REPTILES

TURTLES No surveys for aquatic reptiles (i.e. turtles or crocodiles) have previously been carried out in the study

area. Common turtle species of north Queensland such as Wollumbinia latisternum (saw-shelled turtle)

and Emydura macquarii krefftii (Krefft’s river turtle) are considered likely to occur within the BRW

receiving environment. Other north Queensland species such as Chelondina canni (Cann’s snaked

necked turtle) are considered less likely to occur within the study region as these species prefer lakes,

swamps and billabongs (Wilson and Swan 2013), while the bimodally respiring (mouth and anus

breathing) Elseya irwini (Irwin’s turtle) is also unlikely to occur within the BRW receiving due to the

absence of permanent flowing, well oxygenated waters (EHP, 2016a).

CROCODILES Estuarine

A single threatened reptile (Crocodylus porosus, estuarine crocodile) is listed as potentially occurring

within Elphinstone and Sandy Creeks. The estuarine crocodile is listed under the schedules of

migratory and marine species in the national EPBC Act and is listed under the schedule of vulnerable

species in the state NC Act.

In Queensland the estuarine crocodile inhabits reef, coastal and inland waterways from Gladstone on

the east coast, throughout the Cape York Peninsula and west to the Queensland-Northern Territory

border. A seven-year survey recorded 6444 sightings of the species in the waterways of the Southern

Gulf Plains, Northern Gulf Plains, north-west and north-east Cape York Peninsula, Lakefield National

Park, East Coast Plains, the Burdekin River catchment and the Fitzroy River catchment (Read et al.

2004).

Preferred nesting habitat of the estuarine crocodile includes elevated, isolated freshwater swamps

that do not experience the influence of tidal movements (Webb et al. 1987). Floating rafts of

vegetation also provide important nesting habitat (Webb et al. 1987).

The movement patterns of adult crocodiles in non-tidal areas are not well understood. A study by

Walsh and Whitehead (1993) tracked movement patterns of translocated adults in the Northern

Territory. They found that the movements of translocated adults demonstrated an ability to make

long distance movements up to 280 km. More recently, Campbell et al. (2013) identified that male

estuarine crocodile can travel hundreds of kilometres during the breeding and nesting season.

According to the Atlas of Living Australia (ALA) (2017) and EHP’s Wildlife Online records (EHP, 2016b)

estuarine crocodiles have not been recorded within 10 km of the mine footprint, with the nearest

record approximately 150 river km downstream of the mine footprint (ALA 2017). However, there

have been numerous crocodile sightings including breeding populations within the Burdekin dam.

Considering the semi-perennial nature (persistence of large pools and connecting flows through most

of the year) of the Burdekin River upstream of the dam to the confluence of Elphinstone Creek, it is



suspected that during the wet season estuarine crocodiles could possibly utilise reaches of the

Burdekin River downstream of the mine. While permanent waterholes may remain in parts of

Elphinstone Creek (Ecosure 2012), they are not considered suitable (lack of deep large waterholes,

with largely shallow pools separated by in-channel islands persisting throughout the year) habitat for

the estuarine crocodile and as such are unlikely to occur within Elphinstone Creek.

Freshwater

East coast populations of the least concern (NC Act) Crocodylus johnsoni (freshwater crocodile) are

found in the upper Herbert River, the Burdekin River catchment and the Ross River. Recently (March

2017) a juvenile freshwater crocodile was found within the Ravenswood mine operations area.

Freshwater crocodiles inhabit various freshwater environments, including rivers, creeks, pools,

billabongs, lagoons, and swamps. During the wet season these habitats become inundated with flood

waters which allow crocodiles to move throughout the flood plains. As the water levels drop the

crocodiles tend to congregate in the larger and deeper water bodies, where they prefer to inhabit the

shallower waters at the pool edges.

Freshwater crocodiles may shelter in burrows among the roots of trees fringing the water bodies they

inhabit. In areas where there is permanent water, freshwater crocodiles can be active year-round.

However, they may become dormant in ephemeral areas during the dry winter season. Freshwater

crocodiles can shelter over-winter in dug of creek bank, and a number of animals will often share the

same shelter.

Given the above information it is possible that Elphinstone Creek may provide suitable habitat

particularly during the wet season, while the dry season is unlikely to be used for anything other than

dormant habitat.

2.5 SUBTERRANEAN ECOLOGY

2.5.1 STYGOFAUNA

PROSPECTIVE HABITAT Hydrogeological studies can give an indication of the extent of stygofauna habitat present using

groundwater flow or yield characteristics (aquifer parameters). Critical aquifer characteristics include

hydraulic conductivity, depth to water table and porosity. As mentioned above stygofauna occur more

frequently in alluvial and karst aquifers than in other geological formations (Hancock et al 2005,

Humphreys 2008). In particular, alluvial aquifers that occur beneath floodplains often provide the

following conditions favourable to stygofauna:

• Water table is shallow, so there is recharge of infiltrating rainwater and organic matter, and the

water table is accessible to floodplain tree roots

• There is often some degree of hydrological connectivity with surface rivers. This is particularly

influential in regulated rivers where artificial flow releases from upstream dams may provide aquifer

recharge of organic matter and oxygen in periods where natural surface flow would be absent

• Compared to deeper aquifers, water in alluvial aquifers is young, has a rapid flux, and can have a

lower salinity

These aspects are discussed further in Table 2-6.



Table 2-6. Stygofauna habitat requirements

Aspect Detail

Hydraulic connectivity

Hydraulic conductivity indicates how rapidly water flows through an aquifer. This is important to stygofauna communities because the flux of water through an aquifer often influences how rapidly organic matter and oxygen concentrations can be replenished.

Depth of water table Depth to water table influences the amount of organic matter and oxygen that are available to aquifer food webs. With increasing depth below the land surface, the concentration of organic matter dissolved in infiltrating rainwater diminishes as it is absorbed in transit by soil bacteria and plant roots. Shallow water tables of less than 15 m have been found to favour high diversity in alluvial aquifers in eastern Australia (Hancock and Boulton 2008). Another source of organic matter to aquifer invertebrates is the presence of phreatophytic roots (Jasinska et al. 1996). Root density is likely to be higher in shallower aquifers, and the resultant availability of organic matter provides food to diverse stygofauna communities (Hancock and Boulton 2008).

Connectivity to recharge areas

A large proportion of the organic matter that fuels aquifer food webs has its origin at the surface and enters groundwater in particulate or dissolved forms. Therefore, sections of aquifers that are nearer to recharge areas are likely to have higher diversity and abundance than those that are further away since the transfer of organic matter and oxygen is greater at these sites (Datry et al. 2004).

A space for living Stygofauna can only live in aquifers with enough space for them to move around in. Space is present in the solute cavities in karst, between pesolithic sediments in calcrete, and fractures in sandstone and basalt. In unconsolidated sedimentary aquifers, the size of pore space between particles often correlates to the size of the animals present, with larger species occurring in aquifers of coarser material (Strayer 1994). Also important when considering the space available for living is the connectivity between pores, cavities, and fractures. These act as migration pathways to allow fauna to move around in the aquifer and are likely to be important in recolonising following disturbance.

Food availability Stygofauna have adapted to the resource-starved conditions in aquifers and can tolerate low concentrations of organic matter (Strayer 1994; Hahn 2006). Food is available to stygofauna as particulate organic matter, groundwater bacteria, or as roots of phreatic trees. In its dissolved or fine particulate form, organic matter enters aquifers with recharging water. Dissolved organic matter is taken up by groundwater bacteria, which are then imbibed by smaller stygofauna. Most stygofauna are opportunistic omnivores.

Water regime Local or regional climate and river-flow regimes can influence aquifer recharge, and so affect the organic matter flux in the aquifer. Periods of high, steady rainfall can increase hydrological connectivity between the land surface and the aquifer and can reduce depth to water table. Exchange between rivers, the hyporheic zone, and aquifers can be an important source of nutrients to stygofauna communities (Dole- Olivier et al 1994), so flow fluctuations that enhance hyporheic exchange can subsequently enrich stygofauna communities in deeper parts of the aquifer.



Aspect Detail

Salinity Stygofauna in inland aquifers are generally restricted to fresh or partly brackish water. Hancock and Boulton (2008) suggest that most taxa collected from alluvial aquifers in NSW and Queensland prefer Electrical Conductivity (EC) less than 5000 µS/cm. In surveys of coastal areas and near salt lakes in Western Australia, stygofauna were collected from aquifers with salinities at or exceeding sea water (50 000 µS/cm, Watts and Humphreys 2004). In Queensland stygofauna have been found in aquifers of the Condamine basin where EC was above 50,000 µS/cm (EHP, 2016).

Dissolved Oxygen Stygofauna are able to tolerate very low concentrations of dissolved oxygen. Hahn (2006) observed a strong decrease in abundances below 1.0 mg/L, but found some fauna in concentrations down to 0.5 mg/L. Some taxa are able to survive virtually no oxygen for temporary periods for up to six months (Henry and Danielopol 1999; Malard and Hervant 1999). Aquifers can be heterogeneous environments, so may contain patches of water with sufficient oxygen concentration to be suitable for stygofauna. As dissolved oxygen is measured from water pumped from bores, it can be difficult to identify where these patches occur.

Previous investigations including the Sarsfield Groundwater Impact Assessment (Coffey, 2012) have

identified two main aquifers associated with Ravenswood Mine and surrounds. These include a

shallow regolith aquifer and a deeper fractured rock aquifer, both aquifers are non-artesian. The

classification in some areas may be arbitrary, as the boundaries between the aquifers are gradational,

the formations are hydraulically well connected, and in some regards the function as a single

groundwater system. For discussion purposes they have been separated and are discussed in Table

2-7. A groundwater divide is present with shallow groundwater flows generally mirroring surface flows

either south-east or south-west to Sandy Creek and Elphinstone Creek, respectively (BDH, 2015).

Table 2-7 Defined aquifers (Coffey, 2012)

Aquifer Description

Regolith Shallow unconfined aquifer system within the regolith zone, which consists of soil, decomposed rock and weathered rock. Permeability is provided by inter-granular porosity between disintegrating mineral grains, as well as by relict fracture remaining in the in-situ weathered material. The aquifer also encompasses some thin deposits of alluvial material which are present along some of the larger watercourses. The base of the weathered zone is not sharply defined and merges into fresh crystalline bedrock. In elevated areas, soil and weathered rock may be very thin or absent. The thickness of the regolith aquifer is therefore likely to be quite variable.

Fractured rock Deeper aquifer system within fractured parts of fresh, crystalline bedrock, that is sporadically distributed throughout the Ravenswood Mine and surrounds. The limited occurrence of this aquifer provides an indication of the tightness of the fracture systems and probable lack of hydraulic connectivity between permeable zones.

GROUNDWATER QUALITY Analysis of water samples from the monitoring bores indicates that elevated levels of sulphate,

filterable manganese, and nitrate are characteristic signatures of mine influence on groundwater

quality (JCU, 2016). Sulphate concentrations show widespread elevation down-gradient of mine

facilities, in particular, sulphate is elevated down-gradient of the Sandy Creek Processing Site, the

Nolans Tailings Storage Facility (TSF), the Sarsfield Waste Rock Dump (WRD), the Buck Reef Mine Site,

and in an old backfilled pit in the Ravenswood town area. Filterable Mn concentrations tend to be



elevated in the same locations that sulphate is elevated. Bores around the Nolans TSF and the Sandy

Creek facilities reported higher concentrations of Mn than those around the Sarsfield WRD.

Nitrate concentrations are variable with time and location in groundwater, but are elevated in some

locations above 40 mg/L, most likely as a result of blasting residue within the mine facilities (JCU,

2016). There is some indication that nitrate may also be elevated in background locations; as NO3 has

been measured at concentrations approaching 1 mg/L at OB066_SAR (adjacent to Elphinstone Creek)

and considered to be up-gradient of the mine (JCU, 2016). While the Nolans TSF was a source of

nitrate during the operational phase, concentrations during the 2016 hydraulic year were relatively

low (JCU, 2016). The Sarsfield WRD and Sandy Creek facilities continued to act as sources of nitrate to

groundwater during the 2016 hydraulic year (JCU, 2016).

Concentrations of filterable As in the shallow groundwater system are generally in the range 0.001 to

0.1 mg/L. A localised exception occurs at OB048_SAR drilled into the pit that has been backfilled with

waste rock in the Ravenswood town area, where groundwater filterable As concentrations have been

consistently around 0.5 mg/L. Elevated filterable As concentrations are correlated with significantly

elevated sulphate concentrations in the waste-rock back-fill in Ravenswood township, immediately

down-gradient of Buck Reef WRD, and immediately below Nolans TSF, suggesting that some of the

mine facilities may act as sources of As to groundwater (JCU, 2016).

Physicochemical monitoring during the April 2017 stygofauna survey (Table 2-8) indicate conductivity

and pH ranges were conducive to stygofauna occupancy (Hancock and Boulton, 2005) with

conductivity <5,000 µS/cm and pH between 6.12 to 7.26.

Table 2-8 Physicochemical results for the April 2017 stygofauna surveys

Site Water Depth (m) Temp. (°C) EC (µS/cm) pH

OB007_MTW 24.19 31.3 4033 6.12

OB003_MTW 9.47 27.52 879.5 6.22

OB046A_NOL 12.15 25.24 2443 6.78

OB036_NOL 19.58 27.96 4394 6.69

OB076_NOL 5.33 28.54 1496 6.67

OB069_SAR 5.4 28.18 3089 6.36

OB010_SC 15.94 28.6 1419 6.98

OB027_SC 10.1 29.05 2771 6.64

OB004A_SC 7.75 26.7 4518 6.58

OB057_SAR 8.09 35.82 1020 6.60

OB074_SAR 2.65 29.12 735.5 7.26

OB076_SAR 3.92 28.48 742.7 7.00

OB090_SAR 4.19 27.41 1406 7.26

OB012_MTW 8.46 23.11 1702 6.8



Site Water Depth (m) Temp. (°C) EC (µS/cm) pH

OB023_SC* 12.12

OB025_SC 14.9 27.2 2348 6.64

OB082_SAR 7.4 27.22 1479 6.98

OB097_NOL 7.45 29.37 3522 6.60

OB075_NOL 6.38 29.88 4705 6.86

*malfunctioning meter

STYGOFAUNA SURVEYS - SAMPLING EFFORT To characterise stygofauna communities with the BRWP and REP areas, two surveys were conducted

in May 2016 and April 2017. The sampling effort for both surveys was guided by the Queensland State

‘’Guideline for the Environmental Assessment of Subterranean Aquatic Fauna’’ (DSITI, 2015) and other

relevant documents referred therein including. In additional to DSITI 2015, other state guidelines

(namely Western Australia) have also defined survey technique documents for the assessment of

subterranean fauna, which were also referred to, they include:

• Guidance Statement No. 54a Sampling Methods and Survey Considerations for Subterranean Fauna in

Western Australia (Technical Appendix to Guidance Statement 54) (EPA, 2007); and

• Environmental Assessment Guideline (EAG) 12 for consideration of Subterranean Fauna in Environmental

Impact Assessment in Western Australia (EPA, 2013).

• Technical guidance, sampling methods for subterranean fauna (EPA 2016).

As part of characterising the wider stygofauna community in the REP, Hydrobiology reviewed CGL’s

groundwater sampling network to determine appropriate sampling locations which included both

spatial variability (i.e. sites located upstream and downstream of the mine footprint), target aquifers

(regolith and fractured rock) and any potential impacts to groundwater from varying land uses within

the mine footprint (i.e. sites downstream of the Nolans, Sarsfield and proposed BRW operations).

Bores sampled in Ecosure (2012) were again sampled in May 2016 (Table 2-9, Figure 2-9). Based on

these variables and the requirement to sample bores which have not been pumped for three months

(DSITI 2015), a total of 47 samples from 37 groundwater bores were collected.

Table 2-9 Monitoring bore coordinates and details. Coordinates in GDA 94, UTM Zones 55

Site Locality Easting Northing Sample Year Treatment

Target Aquifer

OB003_MTW Mt Wright 482797 7784398 2017 Upstream Regolith

OB004A_SC Sandy Creek 491958 7777175 2017 Downstream Regolith

OB006A_NOL Nolans 488478 7774805 2017 Downstream Regolith

OB007_MTW Mt Wright 482337 7783663 2017 Downstream Regolith

OB007A_NOL Nolans 488405 7775227 2017 Downstream Regolith

OB008_SC Sandy Creek 491823 7777724 2011, 2016 Upstream Regolith




Target Aquifer

OB010_SC Sandy Creek 492052 7776629 2011, 2016, 2017

Downstream Regolith + Fractured Rock

OB012_MTW Mt Wright 481814 7784245 2017 Upstream Regolith

OB023_SC Sandy Creek 491528 7777780 2016, 2017 Downstream Regolith

OB024_NOL Nolans 491526 7777775 2017 Downstream Regolith

OB024_SC Sandy Creek 491526 7777775 2016, 2017 Upstream Regolith

OB025_SC Sandy Creek 491874 7777772 2017 Upstream Fractured Rock


OB026_SC Sandy Creek 491409 7776715 2017 Downstream Regolith

OB027_SC Sandy Creek 491598 7776652 2017 Downstream Fractured Rock


OB036_NOL Nolans 488468 7775111 2017 Downstream Fractured Rock



OB046A_NOL Nolans 488337 7774374 2016, 2017 Downstream Regolith

OB047_NOL Nolans 488354 7775468 2011, 2016 Downstream Regolith

OB057_SAR Sarsfield 489306 7777620 2017 Upstream Regolith



OB069_SAR Sarsfield 490145 7775866 2017 Downstream Regolith

OB070_NOL Nolans 490247 7775782 2016, 2017 Downstream Regolith + Fractured Rock




OB075_NOL Nolans 488909 7774619 2016, 2017 Downstream Fractured Rock




Target Aquifer

OB076_NOL Nolans 488903 7774619 2016, 2017 Downstream Regolith


OB082_SAR Sarsfield 488647 7777299 2017 Downstream Regolith

OB090_SAR Sarsfield 487628 7776817 2017 Downstream Regolith + Fractured Rock




SAMPLING METHODS Each bore was sampled using CGL’s Bennett sample pump (Bennett Sample Pumps Inc, Texas), which

is a piston-type pump driven by an air compressor. It was capable of pumping water at a rate of

~10L/minute, slightly less in deeper wells (>50 m). Water was pumped through a 50 µm mesh stainless

steel sieve (Figure 2-9). After passing through the sieve, water was collected in buckets to estimate

total pumped volume. Approximately 100 to 300 L of water was pumped (as per DSITI 2015), which

typically exceeded three times the bore volume. For deep bores, this is less than the bore volume but

all that is feasible for the study. In all cases, the pump was lowered to within a metre of the bore

bottom, or as low as possible (pump setup only suitable to ~ 60 m).

Water quality was measured using a Hydrolab MS5. Measurements were taken every 20 L until values

stabilised, then every 100 L. Grab samples were collected by CGL for laboratory analysis.

Figure 2-9 Pump and sieve setup



Figure 2-10 Stygofauna and troglofauna survey bores, 2016 and 2017 survey years



SPECIES SORTING AND IDENTIFICATION In the laboratory, samples were elutriated to separate out heavy sediment particles and sieved into

size fractions using 250, 90 and 53 µm screens. All samples were sorted under a dissecting

microscope. Sorted animals were identified to species or morphospecies using available keys and

species descriptions. When necessary, animals were dissected and examined under a compound

microscope. Morphospecies determinations were based on characters used in species keys.

In accordance with DSITI (2015), the following major taxonomic groups a representative subset of

specimens collected was at a minimum identified to the genus level: amphipoda; copepoda; isopoda;

ostracoda; remipedia; spelaeogriphacea; syncarida; and thermosbaenacea. For the following

taxonomic groups a representative subset of specimens collected were at a minimum were identified

to the order or family level: acarina; coleopteran; decapoda; mollusca; nematode; oligochaete; rotifer;

polychaeta; and turbellaria.

STYGOFAUNA OCCURRENCES AND ABUNDANCES The stygofauna surveys undertaken to date yielded the collection of 1078 individuals consisting of 38

different taxa of six Classes/Orders, including Harpacticoida (12 taxa), Syncarida (seven taxa),

Haplotaxida (four taxa), Isopoda (three taxa), Cyclopoida (three taxa), Popocopida (four taxa),

Enchytraeida (one taxa), Amphipoda (one taxa), Acari (one taxa), Nematoda (one taxa), Bdelloidea (one

taxa) (Table 2-10). Species richness across the REP is relatively diverse by Queensland standards (total

of 98 taxa defined in the State database).

The Nolans area contained the greatest taxa richness (28 taxa), followed by Sandy Creek (19 taxa),

Sarsfield (15 taxa) and Mount Wright (3 taxa). Only two of the 15 taxa identified in the Sarsfield

area/Elphinstone catchment were limited in their distribution (i.e. did not occur within the Nolans

area/Sand Creek catchment), as such the distribution of stygofauna within the Project area suggests

that the noted groundwater divide (BDH, 2015) does not limit habitat connectivity. Additionally,

suggested connectivity between the regolith and fracture rock aquifers, appears to be strongest in the

Nolans/Sandy Creek catchment with only six of the 28 taxa recorded in this area limited to the

fractured rock aquifer. Further surveys would likely indicate presence of these six taxa in the regolith.



Table 2-10 Stygofauna survey results, November 2011, May 2012 and April 2017

Note: Bores described in Table 2-9, but not listed in the above table either contained no stygofauna or were dry at the time of sampling.

03_MTW 04A_SC 07_MTW 12_MTW 23_SC 25_SC 27_SC 36_NOL 45_NOL 57_SAR 69_SAR 70_NOL 71_NOL 72_NOL 74_SAR 76_SAR 90_SAR 94_NOL 96_NOL 97_NOL

2017 2017 2017 2011 2016 2011 2016 2017 2017 2016 2017 2017 2017 2016 2016 2017 ### 2016 2017 2017 2016 2016 2016 2017 2016 2017 2016 2017 2017 2017 2016 2016 2017

Acari

Acari sp. 1

Amphipoda

Amphipoda sp. 1 10

Bdelloidea

Bdelloidea sp. 2:2 1 1 4 1

Cyclopoida

Goniocyclops nr bispinosus 7 3 50 50 4 2 2 1 1 10 3 1 1

Metacyclops sp. 1 1

Metacyclops sp. B05 1 30 2 2 1 15

Enchytraeida

Enchytraeidae sp. B06 (Qld) 20 5

Haplotaxida

Naididae sp. 1 1

Nais communis/variabilis 10 15

Phreodrilidae with dissimilar ventral

chaetae (Qld) 20

Phreodrilidae with similar ventral

chaetae (Qld) 1 5

Harpacticoida

Ameiridae gen. unk. sp. B01 1

Canthocamptidae sp. B07 25 5 1

Canthocamptidae sp. B10 3

Dussartstenocaris sp. B07 50

Kinnecaris sp. B07 7

ngen? Nr Dussartstenocaris sp. B01 15 5

Parapseudoleptomesochra sp. B02 50 30 1 31 1

Parastenocarididae sp. 1

Parastenocaris sp. B35 8 1

Parastenocaris sp. B39 3

Sigmatidium sp. B01 3 1 1

Stygonitocrella SL sp. B04 2 2 1

Isopoda

Microcerberidae sp. 2

Microcerberidae sp. B14 4

Protojaniridae sp. B01 3 3

Nematoda

Nematoda sp. 40 5 2 3 1 2 2 1 1 5 1

Popocopida

Candonidae sp. A 1 6

Candoninae sp. BOS573 2 1

Candoninae sp. BOS929 1

Cyprinopsinae sp. 3 1 1 1

Syncarida

Atopobathynella sp. B28 2

Bathynella sp. B26 1

Notobathynella sp. B10 1 8 6 2 2 10

Parabathynellidae gen. nov. sp. B03 1

Parabathynellidae sp. 2 1 361

Stygocarididae sp. B01 27 24 2 2

Syncarida sp. 1

76_NOL47_NOL08_SC 10_SC

Taxa

46A_NOL 75_NOL



2.5.2 TROGLOFAUNA

PROSPECTIVE HABITAT Knowledge of the geological facies present can also give an indication of the extent of troglofauna

habitat. Similar to stygofauna recent surveys have identified troglofauna from non-karstic geologies

such as pisolite ore beds, and fractured and weathered rock formations.

Troglofauna presence is dependent on geology and, if no fissures or voids are present in the strata, no

troglofauna will occur. If fissures, voids or vugs are present, the pattern of their occurrence will largely

determine the abundance and distribution of troglofauna. Vertical connectivity to the surface is

important for supplying nutrients to maintain populations of different species (plant roots are an

important surface connection), while lateral connectivity of voids is crucial to underground dispersal.

In rock habitats, the occurrence of fissures, voids and vugs is primarily driven by broad rock type

(rocks such as granite typically contain few spaces) and the degree of weathering (e.g. iron ore

formations contain increasing quantities of internal spaces as they weather).

The geology of BRW and the larger REP comprises predominantly diorite, quartz diorite, with minor

gabbro and other intrusive rocks. Minor surficial units in the wider study area occur as outliers of

Tertiary laterite and sandstone, alluvial outwash deposits, and semi-consolidated Quaternary

sandstone. A veneer of red sandy-silt soils and weathered rock are generally present overlying

bedrock. The upper regolith layer generally consists of soil and disintegrated rock, and this layer

merges into weathered rock, which overlies bedrock.

The geology of the BRW and larger REP is shown in Figure 2-11. The main rock types in the study area

are shown on the 1:250,000 scale Charters Towers geological mapsheet (BMR, 1969) as belonging to

the extensive Ordovician to Devonian age Ravenswood Granodiorite complex, which extends from

southwest of the Burdekin River to northeast of the Leichardt Range. At Ravenswood the dominant

bedrock is the Jessop Creek Tonalite, which consists of diorite, quartz diorite and minor gabbro (MIM

Holdings, 1999). Other crystalline intrusive rocks of this complex include granodiorite, granite,

adamellite, monzonite and pegmatite. The bedrock is intersected by several northerly trending faults

in the vicinity of the REP.



Figure 2-11 Regional geology (Coffey, 2012)



Undifferentiated alluvial deposits of limited extent have also been identified in the stream beds of

Sandy Creek and Elphinstone Creek during the July 2011 site visit undertaken by Coffey (2012).

Although these sediments are not indicated on the mapsheet, and their precise distribution is not

known, they are considered likely to be of recent origin.

The surrounding geology is similar to the REP with the exception of some laterite and sandstone

belonging to the Tertiary Campaspe Beds, and alluvial outwash deposits and semi-consolidated

sandstone of the Quaternary Sellheim Formation. Fractures, voids/vugs noted within the REP revealed

habitat suitable for troglofaunal colonisation (Figure 2-12). Additionally, noted root mats

approximately 6 to 7 m bgl in a number of bores also indicate some degree of porosity and may

therefore also provide habitat for troglofauna.

Figure 2-12 Void/vuggs (left photo) and extensive fracture system (right photo) present along the exposed wall of the Sarsfield pit (Coffey,

2012).

PILOT SURVEY - SAMPLING EFFORT An initial pilot study was undertaken to identify the presence of troglofauna within the larger

Ravenswood project footprint (Figure 2-9, Table 2-11). As part of the pilot survey eight traps were

deployed in six monitoring and two exploration bores located with the direct impact zone (BRW pit),

and upstream and downstream of the REP. The survey also included trap deployment within the main

geomorphic zones.

SAMPLING METHODS Custom-made cylindrical PVC traps (250 x 70 mm, entrance holes side and top) were used for trapping

troglofauna (Figure 2-13). Traps were baited with leaf litter (sterilised by microwaving) and lowered

adjacent to the slots of the groundwater bore to allow access. In every fourth bore, a second trap was

set mid-way down the bore. Bores were sealed while traps were set to minimise the ingress of surface

invertebrates. Traps were retrieved six weeks later and their contents (bait and captured fauna) were

emptied into a zip-lock bag and transported to the laboratory for identification.



Figure 2-13 Trap deployment down exploration bore (left photo) and close-up of troglofauna trap (right photo)

SPECIES SORTING AND IDENTIFICATION Troglofauna caught in traps were extracted from the leaf litter using Berlese funnels under halogen

lamps. The heat from the light drives troglofauna and soil invertebrates out of the litter into the base

of the funnel containing 100% ethanol (EPA, 2007). After approximately 72 hours, the ethanol and its

contents were removed and sorted under a dissecting microscope. Litter from each funnel was also

examined under a microscope for any remaining live or dead animals.

All fauna picked from samples were examined for troglomorphic characteristics (lack of eyes and

pigmentation, well developed sensory organs, elongate appendages, vermiform body shape).

Troglofauna were identified to species or morphospecies level, unless damaged, juvenile or the wrong

sex for identification (EPA, 2007). Identifications were made under dissecting and/or compound

microscope, with specimens being dissected as necessary. Unpublished and informal taxonomic keys

were used to assist identification of taxa for which no published keys exist.

TROGLOFAUNA OCCURRENCES AND ABUNDANCES The pilot survey revealed only a single troglofauna species (Ptinella sp. B03) from six bores and eight

troglofaunal traps (Table 2-11). This species appeared to be associated with the weathered geology

across the REP (proposed BRW pit, Nolans TSF and Sandy Creek).

There are currently no published surveys in Queensland concerning troglofauna; however far greater

diversity of up to 80 species has been documented in the Pilbara region of Western Australia

(Ecologia, 2009).

Table 2-11 Troglofauna survey bores and monitoring results

Site Easting Northing

Trap deployment depth (m) Target Geology

Ptinella sp. B03 presence

BRRC_233 488249 7776769 10 and 25 weathered and unweathered

Y (weathered zone)

BRRC_225 488391 7776811 8 and 15 weathered and unweathered

Y (weathered zone)

BRRC_232 488392 7776712 18 unweathered N

OB099_NOL 488964 7774014 10 weathered Y (weathered zone)



Site Easting Northing

Trap deployment depth (m) Target Geology

Ptinella sp. B03 presence

OB027_SC 491597 7776651 10 weathered Y (weathered zone)

OB066_SAR 489475 7778287 4 weathered N



3. AQUATIC ECOLOGY IMPACT AND MITIGATION ASSESSMENT The aquatic ecology of the receiving environment is potentially threatened by activities that change

the geomorphology, hydrology and water of both surface and groundwaters. Impacts posed by the

BRWP can be categorised as being either direct or indirect. Direct impacts, may include:

• Loss of catchment area;

• Creek diversion;

• RO permeate and mine water releases; and



• Changes to the chemistry of groundwater expressions as a result of dry stack tailing and/or waste

rock dump seepage.

Indirect impacts may include:

• Altered groundwater surface expressions due to groundwater drawdowns.

3.1 PROJECT IMPACTS

3.1.1 LOSS OF CATCHMENT AREA The area captured by the BRWP represents 0.4% of the Elphinstone Creek catchment and 6% of the

Elphinstone Creek catchment downstream of Suhrs Creek Dam and upstream of the confluence

between Elphinstone and One Mile Creek. Reduction to runoff volumes into Elphinstone Creek as a

result of the captured area are expected to be minimal. Proposed mining areas are well defined which

will ensure only target areas will be disturbed, thereby limiting the area of impact. Additionally, any

losses will be offset by the releases of RO permeate discharges to Suhrs Creek. The loss of highly

disturbed catchment area within the Elphinstone Creek tributaries will also provide a positive impact

by reducing the risk of continued headward eroding gullying and associated sediment delivery to the

heavily sedimented Elphinstone Creek.

3.1.2 DRAINAGE DIVERSION Much of the proposed works will result in considerable changes to the morphology of the eastern and

central Elphinstone Creek tributaries (tributaries represent minor drainage courses of stream order 1

and 2). The upper reaches of the both tributaries and their supplying catchment will be entirely

replaced by the waste rock dump, while sections of both reaches will require diversion of flows to

accommodate the dump and mine pit. Flood protection levees are also likely to be required to

minimise risk to adjacent infrastructure and should be included in any diversion design. Given the

existing diversion characteristics, it would be expected that bank material will be composed of a

mixture of erodible, fine-grained material (upper bank) and granite outcropping (lower banks), with

bedrock and boulder bed substrate dominating. This should provide stability to the channel margins.

These details should be confirmed following a decision on a final alignment.

No diversion design has been developed as part of this assessment as it is not required under the

Water Act 2000. As such, specific impacts associated with the diversion are difficult to assess. Instead,

potential impacts have been identified based on the existing diversion and our knowledge of diversion

impacts throughout Queensland. The drainages to be diverted are particularly prone to change

through gullying and associated increased sediment supply. As such, potential impacts that may be

seen within the diversion and the reaches up- and downstream may include:

• Rilling, gullying and piping of non-competent bank material;

• Other bank instabilities (scour/failure);

• Increased sediment mobilisation and delivery downstream;

• Upstream migrating headcuts / gullies;

• Loss of connectivity between up- and downstream reaches; and

• Overtopping/breaches of levees adjacent to the diversion channel.

Provided best-practice engineering design is adhered to, these risks/impacts should be low to

negligible.



3.1.3 RO PERMEATE AND MINE WATER RELEASES

CHANGES TO GEOMORPHOLOGY AND HYDROLOGY RO Permeate Releases

Legacy water and Inflows (rainfall, runoff and groundwater) over the project life in the BRW pit will be

RO-treated. RO permeate will be beneficially reused onsite; however should RO treatment rates

exceed demand, then RO permeate will be released to Suhrs Creek. WRM (2017) indicated that the RO

permeate release to Elphinstone Creek are highest at 220 ML/annum during the first four years under

all climatic conditions (WRM, 2017). Post year four the following release scenarios are predicted by

WRM (2017):

• Under wet to very wet climatic conditions:

RO permeate releases increase significantly after Project year 4 to a maximum of 820 ML/a in

Project Year 6 due to the large volume of legacy water still stored in Sarsfield Pit under these

conditions, and the increase in the feed rate to the RO Plant (from 2.96 ML/d to 5.91 ML/d).

RO permeate releases reduce after Project Year 6 to about 100 ML/a in Project Year 9 as the

Sarsfield Pit is completely dewatered and the feed rate to the RO plant is reduced back to 2.96

ML/d.

The RO permeate releases to Suhrs Creek will introduce a continuous flow of approximately 7 L/s in

Project Years 1 to 4, up to 26 L/s in Project Year 6 and approximately 3 L/s after Project Year 9. To

provide some understanding of velocities associated with this predicted discharge of the first four

years, several basic ‘channel’ scenarios and related velocities (using Discharge = Velocity x Area) are

provided below:

• Pipe outlet, 0.2 m diameter – velocity = 0.22 m/s;

• Pipe outlet, 0.5 m diameter – velocity = 0.04 m/s;

• Channel pool, 3m wide 1m deep – velocity = 0.002 m/s; and

• Channel riffle, 1m wide 0.1m deep – velocity = 0.07 m/s.

It is evident from the basic scenarios provided above that 7 L/s equates to very low in-channel

velocities that are unlikely to result in erosion, except where the low flow channel is constricted. The

risk of the impacts of this altered hydrology to channel morphology within Suhrs and Elphinstone post

year 4 will be lower (due to reduced potential maximum release rate from 30 L/s to 26L/s) than that

already described in Hydrobiology (2016).

A water balance for Elphinstone Creek has not been undertaken. Conservatively, it is therefore

assumed that all released water will travel to the confluence of Burdekin River, turning an ephemeral

system to one that will likely flow year-round. Potential impacts associated with this change may

include:

• Scour at the outlet from the RO plant. Flow velocities at the outlet will be largely dependent on

outlet sizing. As such, an appropriately sized outlet should be selected (and modelled) and a suitably

protected chute (as described in Hydrobiology 2016) should be constructed that adequately

dissipates flows prior to entry to Suhrs Creek;

• Notch erosion, which is gradual scour of a bank at a particular height due to regulated flow. This is

typical downstream of a regulated flow release where low flow releases are clear and of a similar

water level for the majority of the time. Notch erosion can lead to bank undercutting and eventual



bank failure. This is likely to occur to some degree in areas where banks are composed of less

cohesive sediments. However, it is unlikely to result in major changes to bank stability due to the

expected low velocities and the inherent robustness of Suhrs and Elphinstone Creeks. If erosion

does occur, it will be a gradual process which can be monitored; and

• Bar / bench and vegetation encroachment and resulting low-flow contraction. Increased regularity

of flows can encourage encroachment. Impacts are expected to be minor, but should be monitored

using methods outlined in the REMP design (JCU 2015).

The change in hydrology is predicted to have a positive effect on the aquatic ecology of Suhrs and

Elphinstone Creeks. The persistence of water and potential creation of larger/deeper pools will in turn

encourage the growth of littoral macrophytes, epiphytes and phytoplankton. Of concern would be the

establishment of toxic blue green algae (BGA). However, their competitive advantages will be

somewhat offset by proliferation of macrophytes. It is possible that some BGA growth could occur

during warmer months, particularly in stable pool habitat and backwaters. An adaptive management

strategy will be necessary to ensure that any potential negative changes (e.g. BGA) are addressed at

an early stage, or prevented. BGA prevention measures are discussed in Table 3-4.

The greater habitat diversity is likely to encourage specialist macroinvertebrate feeders, such as

shredders and scrapers and encourage the recruitment and proliferations of some sensitive taxa (e.g.

mayflies). Phytoplankton and zooplankton are major sources of food for a number of planktivorous

fish species known to occur in Elphinstone Creek. For example, this would likely increase the food

availability for Bony bream, and then in turn provide a food source for predatory species. Black

tandan, Hyrtyl’s tandan would similarly benefit from greater availability of phytoplankton and

invertebrates. Key predatory species such as sleepy cod would potentially benefit from the greater

availability of food fishes. However, they would also require other habitat structure from macrophyte

beds as the increased water clarity would cause them to largely avoid open water habitats.

Macrophyte associated species, such as eastern rainbowfish and purple spotted gudgeon, would

benefit from the potentially greater development of macrophyte beds. However, the increased

availability of macrophytes may also enhance recruitment success of exotic species, particularly

tilapia, which in-turn could adversely affect native fish species.

Mine Water Releases

The mine waste water management system will be upgraded to improve retention and quality of

water released from BRW and Sarsfield projects. The sediment dams are designed to collect and settle

sediment-laden water and will overflow when rainfall exceeds the design criteria. The likelihood of

overflows from the sediment dams is minimised by continuous pump-back of water from sediment

dams to the mine water management system for reuse. Schematics of the water management plan

are reproduced in Appendix B. Accordingly, mine water will be managed as follows:

• Surface runoff from undisturbed areas will be diverted around disturbed areas to tributaries of

Elphinstone and Sandy Creek;

• Overland flows from the proposed Waste Rock Dump (WRD), DSTSF and existing Process Plant will

be redirected to a series of sediment dams, pumped to the Sarsfield Pit and beneficially re-used

onsite;

• Surface runoff from the eastern slopes of DSTSF will drain into a Tailings Storage Facility (TSF) Dam.

The TSF and sediment dams have less than 1% and 61-77% (Elphinstone-Sandy Creek) likelihood of

spilling in any year, respectively (WRM, 2017). A single extreme event within the historical climate

sequence resulted in one modelled spill from the TSF Dam with a dilution ratio in Sandy Creek of



about 1,000 (WRM, 2017). With a dilution ratio about 1,000, the single spill from TSF Dam is likely to be

undetectable in the receiving watercourse (WRM, 2017). The PWP is not expected to spill over the

project life (WRM, 2017). Overflows from sediment dams are only expected to occur during wet

weather conditions when both Elphinstone and Sandy Creek are likely to be flowing. WRM (2017)

estimated that the minimum dilution ratio is 25 and 12 at Elphinstone and Sandy Creeks, respectively

(Table 3-1 and Table 3-2). Elphinstone and Sandy Creeks recorded the lowest median dilution ratio

during project years 2-4 and 6-8, respectively. It should be noted that sediment dams at BRW will be

removed after project year 5 and their catchment rehabilitated.

Table 3-1 Sediment dam spill probability and dilution ratios to Elphinstone Creek (WRM, 2017)

Statistics PY 1 PY 2-4 PY 5 PY 6-13

Probability to spill in any year 61% 62% 59% n/a

Minimum Dilution Ratio 28 25 32 n/a

Median Dilution Ratio 57 53 68 n/a

Average Dilution Ratio 187 240 185 n/a

Table 3-2 Sediment dam spill probability and dilution ratios to Sandy Creek (WRM, 2017)

Sandy Creek PY 1-5 PY 6-8 PY 9-13

Probability to spill in any year 77% 77% 77%

Minimum Dilution Ratio 87 12 12

Median Dilution Ratio 197 29 30

Average Dilution Ratio 1,041 246 266

CHANGES TO WATER QUALITY Proposed water quality release limits for both mine waste water and RO permeate releases are

defined in Table 3-3. The release of RO permeate and mine waste water will afford in most cases

protection to 95% of species. This level of protection is also consistent with that defined by DSITI

(2017) for which the BRWP area is located (i.e. Kirk River sub-catchments which contain moderately

disturbed ecosystems). However, proposed discharge limit for arsenic only accommodates for arsenic

III (0.024 mg/L, trigger defined in ANZECC/ARMCANZ, 2000) and not arsenic V (0.013 mg/L, trigger

defined in ANZECC/ARMCANZ, 2000). CGL will over the coming months undertake Arsenic speciation

investigation to determine detection of Arsenic V in mine waste waters and whether a more stringent

trigger for arsenic should be instated.

Those parameters which are above defined guidelines and triggers or may pose additional risk to

aquatic ecosystems are discussed below.

Sulphate

Sulphate concentrations are above the current WQO defined for the upper Burdekin (above dam)

(DSITI, 2017); however below toxicity triggers defined by Dunlop et al. (2016) of 545 mg/L (protection

of 95% of species). This trigger is based on a water hardness of 550 mg/L and relative proportions of

major ions that include: 23% Na+; 21.1% Ca2+; 5.4% Mg2+; 0.6% K+; 16.3% HCO3-; 28.1% Cl-, and 5.6%



SO42-. The toxicity of sulphate is highly dependent on water hardness and calcium:magnesium ratios,

with greater harness and calcium:magnesium ratios resulting in lower toxicities (Soucek and Hennedy

2005; Davies 2007; Davies and Hall, 2006), both of which are greater in Elphinstone and Sandy Creek

(JCU, 2016) when compared to the testing waters in the Dunlop et al. (2016) study. The release of RO

permeate is likely to lower calcium:magnesium ratios in the receiving environment as such where any

such deficiencies are identified as a result of RO permeate releases, the ionic composition of the RO

permeate should be reassessed and amended to ensure sulphate toxicity does not arise.

Low Ionic Composition Waters

There may be an additional risk to invertebrates that contain a calcium carbonate shell (i.e.

macrocrustaceans, molluscs). RO permeate is typically low in major ions and as such

macrocrustaceans and molluscs may suffer from magnesium and calcium deficiencies where the

water they are exposed to lacks such ions. The RO permeate should be amended prior to release to

ensure that the ionic composition (total dissolved solids used as the release indicator) of the released

permeate is similar to background conditions. Should this occur the risk of impact to such

invertebrates is considered low. However, as a precautionary measure, the integrity (signs of

deformities and calcium:magnesium ratios) of macrocrustacean exoskeletons and shells of any

molluscs should be assessed and incorporated into the current REMP. This would be required where

reductions in calcium:magnesium ratios are noted as a result of RO releases and/or concentrations

are below background levels. Where any such deficiencies are identified as a result of RO permeate

releases, the ionic composition of the RO permeate should be reassessed and amended to ensure

appropriate protection of macrocrustacean and molluscs.

Should final specifications for the RO plant indicate potential contaminants of other metals and

metalloids then these should be reviewed and assessed to ensure protection of aquatic ecosystem

values. This also pertains to other contaminants (i.e. hydrocarbons, non-metallic inorganics, biocides

used in cleaning RO membranes etc.).

Table 3-3 Proposed discharge limits for RO permeate and mine waste water discharges (SLR 2017a)

Parameter (mg/L unless stated otherwise) RO Permeate Mine Waste Water

Electrical conductivity (µS/cm) 2712 8008

pH (pH Unit) 6.5-8.511 6.5-8.511

Turbidity (NTU) 257 25012

Sulfate (SO42-) 4009 4009

Aluminum 0.0554 0.0554

Arsenic 0.0244 0.0244

Cadmium 0.00024 0.00024

Copper 0.00144 0.00144

Lead 0.00344 0.00344

Molybdenum 0.03410 0.03410



Parameter (mg/L unless stated otherwise) RO Permeate Mine Waste Water

Manganese 1.94 1.94

Nickel 0.0114 0.0114

Selenium 0.0114 0.0114

Zinc 0.0084 0.0084

Cyanide (WAD)5 0.56 0.56

Cyanide (as un-ionised HCN, measured as [CN]) 0.0074 0.0074

Nitrate (Total N) 0.74 0.74

1. All metals and metalloids must be measured as both ‘total’ (from analysis of an unfiltered sample) and ‘dissolved’ (from analysis of a field filtered sample). Contaminant limits are based off dissolved

values for metals

2. Based off Queensland Water Quality Guideline (2013), electrical conductivity 75th percentile in the Burdekin Basin

3. Based off Australian Drinking Water Guidelines, version 3.3 (2011), Table 10.6

4. Based off ANZECC (2000) value for 95% species protection, Table 3.4.1

5. WAD CN is Weak Acid Dissociable Cyanide, measured as an indicator of the bio-available cyanide

6. Based off The International Cyanide Management Code (2009), Section 4.5

7. Based off Queensland Water Quality guideline (2013), Section 3.2, Table 3.2.1a

8. Derived from site specific values

9. Based off ANZECC (2000) value for recreation, Table 5.2.3

10. Based off ANZECC (2000) low reliability metals and metalloids, Section 8.3.7.

11. Based off Draft environmental values and water quality guidelines: Burdekin River Basin fresh and estuarine waters (DSITI (2017)) Upper Burdekin River sub-basin catchments – Table 3

12. Based off Draft environmental values and water quality guidelines: Burdekin River Basin fresh and estuarine waters (DSITI (2017)) Upper Burdekin River sub-basin catchments (above dam) for during

event flows – Table 3

3.1.4 1BRINE DISPOSAL The brine waste stream from the RO plant is proposed to be circulated into Sarsfield Pit and

eventually removed off-site by a licensed waste management contractor. Sulphate concentrations in

the Sarsfield pit are only expected to increase slightly from the current scenario of 1,700 mg/L (WRM,

2017) to approximately 2,000 mg/L (Figure 3-1) during project year 2, otherwise peak concentration

reduce to approximately 1,400 mg/L post-project year 5 (WRM, 2017). Additionally, any expressions of

elevated sulphate to surface waters will likely be diluted by RO permeate releases.

3.1.5 GROUNDWATER DRAWDOWNS Removal of groundwater contribution to Elphinstone Creek could occur (95% confidence interval) over

a 1 river km reach (SLR, 2017b) (Figure 3-2) of Elphinstone Creek., while the predicted maximum

extent of drawdown has the potential to reduce groundwater contribution to Elphinstone Creek by up

to 0.03ML/day (SLR, 2017b). Proposed RO permeate releases into the Elphinstone Creek catchment

will offset potential losses to baseflow (SLR, 2017b) as the proposed RO permeate releases are an

order of magnitude greater than the predicted losses. It is still possible that groundwater dependent

ecosystems (i.e. pools along the 1 km reach) may not persist during drier seasons. However, It should

be noted that the aquatic values of the pools are limited offering little habitat during the dry season.

Elphinstone Creek does not support any conservation significant species, as such the BRWP may only

limit habitat presence for common, ubiquitous species which are found throughout the larger

Burdekin catchment.



As discussed in Section 2.4.2, riparian communities along Elphinstone Creek are considered to be

reliant on rainfall as their primary water input. Therefore, the risk of the impacts of altered

groundwater levels to riparian communities is considered low.

Figure 3-1 Estimated sulphate concentration in Sarsfield Pit – single realisation (median climate conditions) (WRM, 2017)

3.1.6 DRY STACK TAILINGS SEEPAGE AND DEPOSITION Tailings produced from the BRWP will be deposited within the new DSTSF in addition to that produced

for the SEP. The DSTSF formed part of the SEP and therefore has been subsequently approved by

DEHP through the EA Amendment process applied to the SEP. The design capacity of the DSTSF has

sufficient volume to contain the BRWP tailings. The new DSTSF is located within the Nolans pit and

then stacked above ground on a lined area to the north of the Nolans pit. Seepage from this lined area

to surrounding aquifers is unlikely and as such does not pose a residual risk to the aquatic ecology of

Elphinstone or Sandy Creek.

3.1.7 WASTE ROCK DUMP SEEPAGE The WRD will be constructed as part of the BRWP will be limited to 365m AHD. The WRD has the

potential to impact groundwater levels in its immediate vicinity through increased rainfall infiltration

and recharge. In addition, groundwater quality may be impacted through leaching of sulphate and

changes in pH as a result of water migration through the WRD material (SLR, 2017). The positioning of

the WRD is such that the natural landform and drainage lines are such that seepage from the WRD

would be captured by the BRWP pit which will act as an effective barrier to migration of contaminants

and a major capture structure for any seepage (SLR, 2017). The design and construction of the WRD

will include the implementation of augmented drainage and seepage management which will further

control water origination from the WRD (SLR, 2017).

3.1.8 SPILLS AND LOCALISED CONTAMINATION Spills or leaks from hydrocarbons or chemicals in the plant area, or from any vehicles or equipment

on the mine site may contaminate soil and surface waters affecting aquatic flora and fauna. On-site

chemicals and hydrocarbons are required to be stored in bunded containers in appropriate storage

0

1,000

2,000

3,000

4,000

5,000

0

1,000

2,000

3,000

4,000

5,000

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Pit

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ry (

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facilities away from drainage lines. In order for a leak to significantly impact, it would need to be a

prolonged discharge or a catastrophic failure. Should the site Environmental Management Plan (EMP)

be correctly implemented surface water contamination is unlikely.



Figure 3-2. BRWP predicted groundwater drawdowns (SLR, 2017b).



3.2 MITIGATION STRATEGY The project impacts and management strategies are presented in Table 3-4. It is intended that water

and sediment quality, aquatic ecology (habitat, macrophytes, riparian vegetation, macroinvertebrates

and fish) monitoring is undertaken as defined in the receiving environment monitoring program

(REMP) (JCU, 2016), and as specified under relevant conditions in the EA. It is assumed, that the REMP

is sufficient to detect changes in aquatic ecology (i.e. sufficient statistical rigour to detect changes in

aquatic ecology). Additional monitoring parameters are also proposed in the below table for the

detection of impacts that may be associated to the releases of RO permeate.

Table 3-4 Potential Impacts and proposed mitigation strategy.

Impacting Process Mitigation Strategy

Loss of Catchment Area

• The mining areas presented in this EA Amendment will need to be clearly defined on the ground through survey, and only target areas will be disturbed. Access tracks for machinery, lay down areas, disposal zones and so on will need to be clearly demarcated to all operators, and suitable monitoring regimes imposed to ensure the area of impact is limited

Drainage Diversion • Design of diversion will reflect existing drainage feature morphology, and tie into downstream watercourse

• Ongoing monitoring of diversion condition as per DNRM (2014) guidelines, this will include monitoring of an impact and control reach

RO Permeate and Mine Discharge Releases

• Flow velocities at the outlet will be dissipated via a rock armoured chute or other control measures as determined during the engineering design phase

• Geomorphology monitoring to assess bed and bank stability which is to be undertaken by a suitably qualified geomorphologist

• Amendment of RO permeate, macronutrients incorporated (i.e. potassium, magnesium, calcium) where total dissolved solids are low.

• Continual implementation of the REMP to identify whether management and mitigation measures are adequate for the protection of defined environmental values.

• Arsenic speciation analyses to identify potential risks associated with arsenic V

• Inclusion of BGA monitoring and where the proliferation of BGA is identified the nutrient composition of RO permeate should be reassessed and amended to ensure that algal blooms do not occur.

• Where downstream water chemistry results indicate a reduction in calcium:magnesium ratios, the assessment of calcium carbonate derived species (prawns, molluscs, etc.) including shell integrity monitoring is to be undertaken. This includes assessment of calcium:magnesium ratios in exoskeletons and/or shell

Brine Disposal • Brine will be circulated into the Sarsfield pit where it will be taken offsite and managed by a licenced management facility

• Monitoring of:

sulphate concentrations in ground and surface waters, and sediment to ensure modelled predictions are realised. Monitoring to be undertaken in accordance with relevant EA conditions and defined REMP (JCU, 2015)

aquatic ecology within downstream reach of the Sarsfield pit. Monitoring to be undertaken in accordance with EA conditions and defined REMP (JCU, 2015)




Groundwater drawdown

• Monitoring will be undertaken to ensure the described impacts do not go beyond the anticipated radius, including:

Monitoring of drawdown rates to ensure that drawdown is occurring as modelled

Monitoring of pool height and widths along Elphinstone Creek

Monitoring of riparian vegetation including condition assessments as per the REMP (JCU, 2015)

Dry Stack Tailing Seepage and Deposition

• Monitoring of water table levels to ensure that seepage is not occurring

• Where seepage is identified ongoing groundwater chemistry monitoring to ensure no changes to groundwater composition are occurring

• Compliance monitoring implementation as defined for RO permeate and mine waste water discharges above.

Waste Rock Dump Seepage

• As per dry stack tailings seepage and deposition above

Spills and localised contamination

• Spills to be cleaned up immediately

• Storage of fuels and reagents to be in bunded areas to prevent contamination of the environment

• REMP implementation as defined for RO permeate and mine waste water discharges above.



4. SUBTERRANEAN FAUNA IMPACT AND MITIGATION ASSESSMENT Subterranean fauna (stygofauna and troglofauna) are potentially threatened by activities that change

the quantity or quality of groundwater (largely affect stygofauna), disrupt connectivity between the

surface or removing living space. This has become a particular issue for mining proponents over the

last decade or so principally because of the perceived biodiversity value of stygofauna and the fact

that little is known of their water quality requirements.

Impacts posed by BRWP can be categorised as being either direct or indirect. Direct impacts, in order

of severity of impact posed, may include:



• Mine pit excavation;

• Dewatering during mining operations;

• Contamination of groundwater from spills and leaks; and

• Changes to groundwater chemistry as a result of dry stack tailing and waste rock dump seepage.

Indirect impacts may include:

• Changes in groundwater flows due to altered sub-surface hydrology during mining.

4.1 PROJECT IMPACTS

4.1.1 MINE PIT EXCAVATION The removal of habitat through mining excavation poses the greater risk to the conservation of

stygofauna and troglofauna species relative to the lowering of the groundwater table only. Mining

excavation will remove potential habitat permanently with no prospect for rehabilitation.

Subterranean fauna habitat that occurs within the mine pit boundaries will be lost as a result of

mining excavation and will represent a residual impact. Avoidance and minimisation measures to

reduce the impact of mining excavation on components of the subterranean fauna assemblage

recorded are limited. The mine pit excavation area for BRW are approximately 29 ha.

4.1.2 DEWATERING Groundwater drawdowns are considered to have greater impacts on stygofauna compared to

troglofauna because lowering of the groundwater table can directly reduce the extent of saturated

stygofauna habitat available.

In the case of troglofauna, their reliance on stable and relatively high humid conditions can make

them susceptible to artificially changing water tables, particularly if the lowering of the water table is

sufficient to dry out the inhabited zone which could have significant impacts on any troglofauna

species present. In addition, the lowering of the water table could mean that portions of saturated

geology containing suitable habitable voids will become unsaturated and potentially available for

colonisation by troglofauna.

BWR pit requires dewatering, the extent of which is based on the size of the area to be mined, which is

predicted to lower the water table. Based on SLR (2017b), potential changes to groundwater levels are

confined to the area around the BRW Pit (Figure 3-2). It is therefore anticipated that groundwater

dependent ecosystems within the vicinity of the pit will become limited due to the localised

groundwater impacts, thus potential impacts to stygofauna within the immediate vicinity of the pits is

possible. Beyond the drawdown radius of influence, the potential impacts related to changes in

groundwater level are expected to be negligible.

Based on stygofaunal taxa distributions recorded in the 2016 and 2017 surveys, there appears to be a

high degree of habitat connectivity between both the regolith and fractured rock aquifers and also

spatially between upstream and downstream areas. For instance, taxa recorded in downstream areas

of the BRW and Sarsfield were also noted in upstream areas. Additionally, only four (Bdelloidea sp.,

Cyprinopsinae sp., Sigmatidium sp. B01, Stygocarididae sp. B01) of the 37 taxa identified have not been

previously recorded in Queensland. It should be noted that comparisons of present stygofauna

against the Queensland database are largely limited to family level identification. The current State

database contains few taxa which have been identified to genus level identification and has virtually

no individuals identified to species level. Given the noted habitat connectivity across the Project area



and surrounds, and the spatial distribution of these four taxa (i.e. recorded in upstream bores) these

species are not expected to be at risk from Project development.

Based on the pilot survey for troglofauna, the genus of the single species recorded Ptinella sp. B03 has

been identified across the Pilbara region of Western Australia (Bennelongia, 2015). In the Project area,

this species appeared to be associated with the weathered geology across the Project Area (proposed

BRW pit, Nolans TSF and Sandy Creek). It is likely that Ptinella sp. B03 makes use of the same habitat

outside the Project area, given the obvious habitat connectivity identified by its distribution; and

therefore would not be at risk from Project development. However, additional collection as defined in

the Subterranean Fauna Monitoring and Management Plan (SFMMP) (Hydrobiology, 2017) is required

to demonstrate this.

4.1.3 BRINE DISPOSAL Brine from the RO treatment plant will be managed as detailed in Section 3.1.4. Should sulphate in the

surrounding groundwaters increase as a result of the noted short-term increase in the pit, they are

unlikely to impact subterranean fauna. This is based on the fact the both the Noland and Sarsfield

areas contained the greater species richness and abundances across the REP, which also contained

some of the highest concentrations of sulphate (1,600 – 3,200 mg/L) (JCU, 2016).

Little is known about stygofauna sensitivity. A single study (Reboleira et al. 2013) investigated acute

toxicity of copper sulphate and potassium dichromate on a single stygofauna species (Proasellus spp.)

and common freshwater macrocrustacean (Daphnia magna). Proasellus spp. was found to be

remarkably more tolerant than the epigean D. magna and conclude that stygofauna adaption to

groundwater life and tolerance to a wider range of environmental conditions is a key factor in their

groundwater colonisation.

4.1.4 DRY STACK TAILINGS SEEPAGE AND DEPOSITION As per Section 3.1.6. The deposited tailings could in turn provide suitable substrate for troglofauna

colonisation.

4.1.5 WASTE ROCK SUMP SEEPAGE As per Section 3.1.7, any seepage are expected to be captured by the BRW pit (SLR, 2017b).

4.1.6 SPILLS AND LOCALISED CONTAMINATION Spills or leaks from hydrocarbons or chemicals in the plant area, or from any vehicles or equipment

on the mine site may contaminate soil and groundwater affecting subterranean fauna communities.

On-site chemicals and hydrocarbons are required to be stored in bunded containers in appropriate

storage facilities away from drainage lines. In order for a leak to significantly impact stygofauna

species, it would need to be a prolonged discharge or a catastrophic failure. Should the site

Environmental Management Plan (EMP) be correctly implemented groundwater contamination is

unlikely.

4.2 MITIGATION STRATEGY The project impacts and management strategies are presented in Table 4-1. It is intended that

groundwater levels and chemistry monitoring is undertaken as defined in the receiving environment

monitoring program (REMP) (JCU, 2016), and as specified under relevant conditions in the EA,

including the developed Groundwater Management Plan (condition E21 of the EA). It is assumed, that

defined groundwater monitoring is sufficient to detect changes in groundwater levels and chemistry

(i.e. sufficient statistical rigour to detect changes). Specific monitoring of subterranean fauna including



frequency, monitoring locations and rationale are defined in the SFMMP (Hydrobiology, 2017). This

includes management objectives, performance criteria, trigger levels and contingency measures.

Table 4-1 Potential Impacts and proposed mitigation strategy.


Mine pit excavation • The mining areas will need to be clearly defined on the ground through survey, and only target areas will be disturbed. Access tracks for machinery, lay down areas, disposal zones and so on will need to be clearly demarcated to all operators, and suitable monitoring regimes imposed to ensure the area of impact is limited

• Water barriers installed to prevent lateral flows of water and reduce the need for dewatering

Dewatering • Monitoring of drawdown rates to ensure that drawdown is occurring as modelled

• Ongoing groundwater chemistry monitoring to ensure no changes to groundwater quality is occurring

• Groundwater abstraction rates kept within approved Project limits

Brine disposal • Brine will be circulated into the Sarsfield pit where it will be taken offsite and managed by a licenced management facility

• Monitoring of:

sulphate concentrations in ground and surface waters, and sediment to ensure modelled predictions are realised. Monitoring to be undertaken in accordance with EA conditions and defined REMP (JCU, 2015)

subterranean fauna within downstream reach of the Sarsfield pit. Monitoring to be undertaken in accordance with defined SFMMP

Dry Stack Tailing Seepage and Deposition

• Monitoring of water table levels to ensure that seepage is not occurring

• Where seepage is identified ongoing groundwater chemistry monitoring to ensure no changes to groundwater composition are occurring

• Sampling of established subterranean fauna bores to ensure assemblages are persisting within the receiving environment of the Project

Waste Rock Dump Seepage

• Maintain seepage recovery system

• Monitoring of water table levels and quality to ensure that seepage is

not occurring beyond the operational footprint of the Sarsfield and

BRW WRDs

• Sampling of established subterranean fauna bores to ensure assemblages are persisting within the Project receiving environment

Spills and localised contamination

• Spills to be cleaned up immediately

• Storage of fuels and reagents to be in bunded areas to prevent contamination of the environment

• Regular monitoring of local groundwater for contaminants to identify whether fuels or reagents are making their way into the environment. Currently, the EA defines groundwater quality monitoring to be undertaken every two months.



5. SUMMARY AND RECOMMENDATIONS Aquatic ecosystems in the vicinity of the project area demonstrate the disturbed nature of the mine

footprint and greater sub-catchments of Elphinstone and Sandy Creeks. No state or federally listed

species are known or are considered likely to occur within the Buck Reef West Project (BRWP) or

greater Ravenswood Expansion Project (REP). The potential impacts to these aquatic ecosystems in

relation to the groundwater drawdowns proposed releases of mine waste waters, RO permeate and

seepage from tailings and waste rock dumps based on the proposed mine water management

program were assessed.

Removal of groundwater contribution to Elphinstone Creek could occur (95% confidence interval) over

a 1 km reach (SLR, 2017b), though projected losses of 0.03 ML/d are potentially offset by proposed RO

permeate releases. It is still possible that groundwater dependent ecosystems (i.e. pools along the 1

km reach) may not persist during drier seasons. Should groundwater expressions into Elphinstone

Creek not occur over the identified reach then it will likely limit habitat for common, ubiquitous

species found throughout the larger Burdekin catchment. Based on these potential impacts the

following actions are recommended:

• Monitoring of drawdown rates to ensure that drawdown extent and depth are occurring as

modelled;



• Monitoring of pool habitat (i.e. pool depths and widths) along Elphinstone Creek; and

• Monitoring of riparian vegetation including condition assessments as per the REMP (JCU, 2015).

Seepage from the proposed waster rock dump are expected to drain into the BRW pit (SLR, 2017b)

where they will be pump to the RO plant for treatment. Tailings produced from the BRWP will be

deposited within the new dray stack tailing storage facility which has sufficient volume to contain the

BRWP tailings. The new DSTSF is located within the Nolans pit and then stacked above ground on a

lined area to the north of the Nolans pit. In accordance with defined EA and current groundwater

monitoring programs, ongoing monitoring of groundwaters levels and chemistry are recommended to

ensure seepages are not entering or impacting the receiving environment.

The proposed upgrades to the mine water management will likely improve water quality in both

Elphinstone and Sandy Creek. However, there are still inherent risks associated with the releases of

mine affected waters, including elevation in sulphate and potentially Arsenic V. Based on these

potential impacts the following actions are recommended:

• Implementation of a release monitoring program to characterise water quality within the dams and

downstream and upstream environments;

• Arsenic speciation investigation to determine whether Arsenic V should be accommodated in mine

waste water releases;

• Monitoring of aquatic ecosystems in accordance with the proposed REMP (JCU 2015).

The continual release of RO permeate based on the proposed release trigger limits (WRM, 2017) are

likely to present a low risk to the aquatic ecosystem values of Elphinstone Creek. In fact, the additional

water supply is likely to establish additional habitat with ongoing positive effects to macroinvertebrate

and fish communities, albeit a temporary change from the ‘natural’ ephemeral condition of the

waterways. To ensure no detrimental effects to the aquatic ecosystem values the following actions are

recommended:

• Monitoring of aquatic ecosystems in accordance with the current REMP (JCU, 2015). Additionally, the

following monitoring item should be added to the REMP:

Where reductions in calcium and magnesium concentrations are noted, assessment of calcium

carbonate derived species (prawns, molluscs, etc.) including shell integrity monitoring such as

calcium:magnesium ratios

Blue green alga and phytoplankton monitoring

• Amendment of RO permeate where total dissolved solids are not consistent with background water

quality conditions of Elphinstone Creek.

Stygofauna surveys within the mine footprint and surrounds revealed a diverse community by

Queensland standards. It is anticipated that groundwater level impacts will be constrained to the

immediate area surrounding the BRW Pit. Interestingly, species richness and abundances are higher

downstream of the Nolans TSF and Sarsfield pit, which have elevated concentrations of some metals,

nitrates and sulphate. The distribution of stygofauna within BRW and wider REP suggests a high

degree of habitat connectivity both spatially and between the regolith and fractured rock aquifers with

most species being ubiquitous (i.e. most species present upstream and downstream of the REP and

within the regolith and fractured rock aquifers). In contrast, only a single troglofauna species was

encountered during the initial pilot study undertaken in May 2016. This species was recorded across

BRW and the REP within the weathered geology. Specific monitoring of subterranean fauna are

defined in the subterranean fauna monitoring and management program (SFMMP). This includes



ongoing monitoring, management objectives, performance criteria, trigger levels and contingency

measures to protect and ensure the persistence of subterranean fauna.


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APPENDIX A. FIVE YEAR PROJECT OVERVIEW

APPENDIX B. WATER MANAGEMENT LAYOUT

S T R E E T P O S T A L C O N T A C T

7 Forrest Avenue

East Perth 6004

WESTERN AUSTRALIA

PO Box 6917

East Perth 6892

WESTERN AUSTRALIA

+61 (0)8 6218 0900 P

+61 (0)8 6218 0934 F [email protected]

A B N 68 120 964 650 www.hydrobiology.biz

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Application for amendment of an environmental authority ... · PDF fileTable 2-2 Macrophyte species recorded at each site (Ecosure, 2012) . 18 Table 2-3 Pairwise ANOSIM comparisons