Terrestrial Flora and Vegetation Section 4.1 |
IMPACT ASSESSMENT
4
SECTION .1 AND VEGETATION FLORA TERRESTRIAL TERRESTRIAL FLORA AND VEGETATION SECTION 4.1 |
This page is intentionally left blank
11-i Jervois Base Metal Project
Jervois Base Metal Project VOLUME 2 Impact Assessment
SECTION 4.1| TERRESTRIAL FLORA AND VEGETATION
4.1 Terrestrial Flora and Vegetation
4.1.1. Introduction The Jervois Base Metal Project Environmental Impact Statement (EIS) Terms of Reference has identified terrestrial flora and vegetation as a preliminary environmental factor that may be impacted by the Project. As such, the EIS is to provide sufficient information regarding the existing environment, the potential impacts and risks arising from the Project and the proposed management and mitigation measures to be implemented to meet the Northern Territory Environment Protection Authority (NT EPA) objectives. The NT EPA’s objective related to terrestrial flora and vegetation is to: “maintain the conservation status, diversity, ecological integrity, geographic distribution and productivity of terrestrial flora and vegetation at species and ecosystem levels through avoidance or management of adverse impacts”.
The NT EPA has Guidelines for Assessment of Impacts on Terrestrial Biodiversity (NT EPA, 2013) that provide guidance as to the level of detail required for terrestrial flora and vegetation within the EIS document. As recommended by the guideline, this Section of the EIS has aimed to include detail on the following concepts, being the: • vegetation of proposed development sites and the immediately adjacent area
4.1-1 Jervois Base Metal Project
Impact Assessment
• presence and distribution of critical habitats (Territory Parks and Wildlife Conservation Act 2014 (TPWCA) or listed threatened ecological communities (TEC) (Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)) • threatened flora species (as listed under the TPWCA and/or EPBC Act) of proposed development sites and immediately adjacent areas • local and regional conservation status of vegetation types and threatened flora present • potential impacts of projects on vegetation and threatened flora in, adjacent to, and downstream from development sites • conservation significance of a development’s impacts on vegetation and threatened flora at local and regional levels; and • Northern Territory Land Clearing Guidelines (NT NREAS, 2010). Whilst vegetation clearing does not require approval under the Planning Act 2009, the Guidelines for Assessment of Impacts on Terrestrial Biodiversity (NT EPA, 2013) will be taken into consideration and used for guidance in relation to clearing within waterway buffer areas. In order to satisfy the above listed requirements of the terrestrial flora and vegetation assessment, a number of ecological investigations were undertaken by Low Ecological Services P/L between 1985 and 2018. The studies included desktop assessment (i.e. interrogation of spatial databases and reviews of relevant literature) and field work involving on-ground vegetation surveys in 1999, 2012, 2013, 2017 and 2018. The reports from these ecological investigations appear in Appendix C-7. Relevant legislation There are a number of pieces of legislation written by the Commonwealth and Northern Territory governments that may be relevant to the terrestrial flora and vegetation potentially impacted by the Project, including: • Environment Protection and Biodiversity Conservation Act, 1999 (Commonwealth) • Environmental Assessment Act 1994 (Northern Territory) • Environmental Protection Act 2012 (Northern Territory) • Biological Control Act 2011 (Northern Territory) • Territory Parks and Wildlife Conservation Act 2014 (Northern Territory); and • Weeds Management Act 2001 (Northern Territory). Where relevant, the EIS has addressed the requirements of the legislation within the document. It is noted that the Project was referred to the Commonwealth Department of Environment and Energy (DEE) in November 2013 and was deemed a non-controlled action.
4.1.2. Relevant Activities The Project is described as the re-opening of a mine. The Project area has been the subject of historic exploration and mining by various operators since 1929. Existing infrastructure at the site includes open pits, access roads, ruins from an old village and several mines and processing sites, waste rock dumps, tailings storage facilities, evaporation dams, and drains and sumps. The Project involves mining copper and other base metals from up to five deposits. Ore would be processed onsite using a crushing, grinding and flotation plant, producing copper and lead/zinc concentrate.
The proposed Project infrastructure includes a processing plant, workshops, laydown areas, an explosive magazine, offices, warehouses, a laboratory, haul roads, sewage treatment systems, 12 MW diesel and/or gas fired power station, powerlines, water storages and an accommodation camp. The workforce is estimated to peak at approximately 300 staff during full production of underground and open cut operations, and will operate on a drive-in drive-out and fly-in fly-out basis. The Project was deemed “not a controlled action” under the EPBC Act.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-2
Environmental Impact Statement
The proposed activities that may have a significant impact on and/or pose a direct or indirect risk to flora and vegetation values, are described as follows: • Construction of associated infrastructure (i.e. topsoil stockpiles, workshops, laydown areas, explosives magazine, offices, warehouse, laboratory, haul roads, sewage treatment systems, pipelines, power station (diesel or gas), powerlines, water storages and accommodation camp. • Construction of open pits to access ore • Construction of underground mines to access ore • Stockpiling of ore • Stockpiling of waste on purpose built waste landforms adjacent to open pits • Transport of ore to ROM processing pad • Concentration of ore using standard flotation processes to produce concentrate containing copper sulphide and subordinate silver and other metals • Discharge of thickened tailings to a purpose built above ground tailings storage facility (TSF) near the processing plant; and • Transport of concentrate in enclosed truck containers off-site via the Plenty and Stuart highways to Alice Springs where it will be loaded onto trains for transport to Darwin and/or Adelaide.
Potential impacts and risks associated with these activities include: • Vegetation clearing • Impacts to threatened flora • Introduction of exotic flora • Dust pollution • Erosion and sedimentation • Changes in hydrology • Release of contaminants (including from tailings dams and waste rock); and • Bushfire. These impacts and risks are discussed in detail below in Section 4.1.5.
4.1.3. Existing environment Climate Climate statistics have been recorded at Jervois Station Homestead (Australian Bureau of Meteorology Station 015602) 35 km south of the mine site since 1966. The climate of the Jervois area is semi-arid, with predominantly summer rainfall occurring between November and April. The warmest months are October to March, with mean daily maximum temperatures over 33°C (Australian Government Bureau of Meteorology, 2017). The maximum average monthly temperature is 38.4°C in January (Australian Government Bureau of Meteorology, 2017). The coolest months are June to September with mean minimum temperatures under 8˚C. The minimum average monthly temperature is 5.4 ⁰C occurring in July (Australian Government Bureau of Meteorology, 2017). Relative humidity averages at 27.8% in the summer months and 38.5% during the winter months (Australian Government Bureau of Meteorology, 2017). The predominant wind direction is east and south-east although during storms and rainfall periods, the winds are predominantly from the west (Australian Government Bureau of Meteorology, 2017).
4.1-3 Jervois Base Metal Project
Impact Assessment
Rainfall records measured at Jervois Station since 1966 show a mean annual rainfall of 295.4 mm. Annual rainfall varies widely, with a range of 95.8 mm (2013) to 933.4 mm (2010) (Australian Government Bureau of Meteorology, 2017). Long-term rainfall trends show a pattern characteristic of the northern Australian arid zone, whereby long dry periods (rainfall around or below the annual average) are interrupted by short, large magnitude rainfall events lasting approximately 12 to 15 months. This rainfall variation is linked to the El-Nino Southern Oscillation phenomenon, whereby the El-Nino phase is often linked to drought and the La-Nina phase is often linked to high rainfall. Most rainfall occurs between November and April, when flooding can occur following storm events.
Biogeographic region The Interim Biogeographic Regionalisation of Australia (IBRA Version 7) provides a broad division of Australia into 89 geographically distinct bioregions based on common climate, geology, landform, native vegetation and species information (DSEWPC, 2012). The Project area lies at the south edge of the Channel Country bioregion (Thackway, 1995). Further refinement of these regions into 419 sub- regions does not affect The Channel Country bioregion which is located on the Queensland (QLD), New South Wales (NSW), South Australia (SA) and NT borders, with 8% of the bioregion in the NT (Bastin, 2008). The Channel Country bioregion is characterised by braided, flood and alluvial plains, which are surrounded by gravel or gibber plains, dunefields and low ranges (Bastin, 2008). The predominant vegetation is Mitchell grass, gidgee and spinifex (Bastin, 2008). The predominant land use in the Channel Country bioregion is grazing (91% of total area (Bastin, 2008)). There are no reserves or protected areas in the Channel Country bioregion (Baker, 2005).
Geology Base metal mineralisation at Jervois is hosted by a lower-to-middle amphibolite grade metasedimentary sequence of the Bonya Metamorphics. The base metal mineralisation at Jervois is strata bound and contained within steeply dipping lenticular bodies (lodes) of calc-silicate, garnet- chlorite-magnetite rock and garnet-magnetite quartzite, within a thick succession of spotted andalusite-cordierite schist and quartz-sericite-magnetite schist. The mineralised sequence has a strike length of some 12 kilometres and a stratigraphic thickness up to about 600 metres. Mineralisation consists of veinlets and disseminations of chalcopyrite in the fresh zone with malachite/azurite/chalcocite in the oxide zone. In addition, smaller scale lenses of high-grade galena (and sphalerite) semi- massive to massive mineralisation occur in fresh rocks with oxide equivalents including cerussite and anglesite. Generally, these lenses are associated with more carbonate-rich host rocks occurring at Green Parrot, Reward and Bellbird North.
A detailed discussion of the geology including mineralisation and extent of ore body is provided in Section 3.1.2 Regional Geology.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-4
Environmental Impact Statement
Hydrology The Jervois Project area is in the upper catchment of the Hay River Basin, which ultimately feeds into Lake Eyre in the north of South Australia. The drainage lines that intersect the Project area feed into the Marshall River to the south and Arthur Creek to the north, which in turn converge into the Hay River, approximately 60 kilometres south-east of the Project area. Surface water in the Project area and surrounding region is ephemeral and the creeks hold water during and after rainfall events. Drainage lines originating in the Jervois Range, include Unca Creek. Unca Creek and its tributaries drain to the east through the Project area and north-east towards Arthur Creek, but flood out through the broad drainage plain to the south-east. Other watercourses in the surrounding area include: Daylight Creek 4 km south-west, Midnight Creek 7 km south and Bonya Creek 11 km south-west.
Jervois Dam is an artificial water reservoir at the north-west corner of the Project area, which holds a substantial volume of water for several years following rainfall. It was constructed for previous mining operations in the 1930’s and is the largest and most permanent surface water body in the Jervois Region. Faulty construction resulted in a pervious layer in the dam wall which allows seepage which provides long term irrigation for the area immediately east of the dam. It is planned to repair this leak to enable a larger quantity of water to be available for the mining process.
Ground water availability on Jervois Station has always been a problem (Low Ecological Services P/L, 1985). Water from Palaeozoic sediments is frequently salty (Black, 1984) but fault and fracture lines in metamorphic and igneous rock may provide fresh water. Deep Quaternary beds through which major water courses flow can yield good supplies of fresh water. Unca Bore on the project area is high in salt content at 3380 TDS.
Fire history Information on the fire history of the region is provided by the North Australia Fire Information (NAFI) website (North Australia and Rangelands Fire Information, 2017). Fire histories have been mapped to the nearest 1 km for years 1997 – 2010 and to the nearest 250 m for years 2004 onwards. Since 1997, the Project area has only been burnt once, in 2002 following the very wet years from 1999 to 2001. Widespread fires that burnt much of Central Australia in 2011 and the beginning of 2012 did not affect the Project area. However, a small isolated fire occurred by the Jervois Dam in 2011. The northern half of the project area has not experienced any fires since 1997.
4.1-5 Jervois Base Metal Project
Impact Assessment
4.1.4. Flora Characteristics of the Project Area Ecological investigations were undertaken by Low Ecological Services P/L between 1985 and 2018. The studies included desktop assessment and field work involving on-ground vegetation surveys in 1999, 2012, 2013, 2017 and 2018.
Desktop assessment The database review and GIS mapping of several data sources provided an ecological context of the landscape, vegetation, habitats and climate of the lease areas. The sources include: • Climate data online (Australian Government Bureau of Meteorology, 2017) • Interim Biogeographic Regionalisation of Australia (IBRA) (Thackway, 1995) • Digital Atlas of Australian Soils (Northcote, 1968) • Vegetation Survey of the Northern Territory Australia: Notes to accompany 1: 1,000, 000 Map Sheets (Wilson, 1990) • Land Systems of the Alice Springs Area, Northern Territory, Australia (Perry, 1962) • Fire history (North Australia and Rangelands Fire Information, 2017) • Aerial photographs and satellite imagery • EPBC Protected Matters Search Tool (PMST) (Department of Environment & Energy (DEE), 2017) • NT Species Atlas (Department of Environment and Natural Resources (DENR), 2017) • Jervois Base Metal Project Surface Water Impact Assessment (WRM Water & Environment P/L, 2018); and • Jervois Base Metal Project Groundwater Impact Assessment (CloudGMS, 2018).
Vegetation surveys Field surveys were conducted by LES in the late dry (1999 and 2017) and in the post wet (2012, 2013 and 2018), including a total of 25 sites encompassing all land units in the Project area. Survey methods for vegetation surveys and landscape description were based on “Northern Territory Guidelines and Field Methodology for Vegetation Survey and Mapping” (Brocklehurst, 2007) and “A resource assessment towards a conservation strategy for the Finke Bioregion” (Neave, 2004). However, due to the sparse nature of the vegetation, 100 m point-line transects were undertaken (rather than 20x20m quadrats). This is an effective that is more suited for measuring rangeland vegetation characterised by sparse vegetation cover (Floyd & Anderson, 1987). This 100 m point-line transect provided a list of flora species at the site and their percentage cover, as well as the percentage of other ground cover types (e.g. litter, rocks, bare ground). If survey sites had more than one vegetation type, an additional transect was undertaken within each distinct vegetation type. Flora species lists were completed by undertaking an area search surrounding the transect to record additional species. Voucher specimens were taken where plants could not be identified in the field. Voucher specimens were identified by experienced botanist Des Nelson with reference to the NT Herbarium, Alice Springs.
Additional targeted surveys were conducted for flora species of conservation significance listed under the TPWC Act that were identified in database searches as potentially occurring within the Project area, such as: • Eremophila cordatisepala • Bolboschoenus caldwellii • Sauropus rigens; and • Sida intricate.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-6
Environmental Impact Statement
Targeted survey involved active searches of suitable habitat areas and recording locations where threatened flora are located. Where a threatened species was located, all individual plants were counted (where feasible). If the plant density was too great a density estimate was undertaken using a 20m x 20m quadrat.
4.1-7 Jervois Base Metal Project
Impact Assessment
Figure 4.1-1 Field Survey Sites
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-8
Environmental Impact Statement
4.1.3.1 Vegetation Communities
Existing vegetation mapping Vegetation communities in the Project area were mapped at a scale of 1: 1,000,000 in the Vegetation Survey of the Northern Territory (Wilson, 1990). Two broad vegetation classes occur across the Project area. These vegetation types closely correspond to land system boundaries, with Class 74 occurring within the Sonder land system, while Class 71 covers the remainder of the project area. These two vegetation classes are defined in Table 4.1-1.
Table 4.1-1 Description of vegetation types within the Project area Vegetation Broad vegetation Structural formation Fine vegetation description Unit classification 71 Acacia with grass Sparse shrubland Acacia aneura (Mulga) tall understory sparse shrubland with grassland understory 74 Acacia with grass Sparse shrubland Acacia stowardii (now sibirica) understory (Bastard Mulga), Cassia,, Eremophila (Fuschsia) sparse shrubland
Surveyed vegetation communities There are clear relationships between landform, soil and vegetation across the NT. A unique integrated or ‘land unit’ approach to mapping landscape properties has been practiced across the Territory for many years (Brocklehurst, 2007), although the method is not recognised within the Northern Territory Bioregions Assessment (which only describes vegetation units) (Baker, 2005). Integrating soil, landform and vegetation data has allowed extensive value adding to datasets. Spatial data and mapping products can now contain soil and landform information as well as agricultural potential, erosion risk, vegetation information, native pasture ratings and sensitive or significant habitats. Integrated surveys include: ‘land systems’ and ‘land units’. The concept of a land system is defined as “an area or group of areas, throughout which there is a recurring pattern of topography (land forms), soils and vegetation, a land system being an assemblage of varying proportions of land units” (Brocklehurst, 2007).
Three broad land systems (Sonder, Bond Springs and Unca) occur within the Project area (Perry, 1962). Nine land units have been identified as occurring within the project area. The majority of the Project area falls within the Bond Springs (Bs) land system, consisting mainly of unit Bs4; a unit of undulating plains and drainage flats at the base of other Bs units. This system is dissected by numerous drainage lines and tributary channels that make up the Bs5 land unit. The Sonder (So) and Unca (Uc) land systems occupy the north-western and southern portions of the project area respectively. The So system shows distinct differences in landscape and geology, being composed of sedimentary sandstone and quartzite in the form of steep, benched cuestas and ridges. Three land units exist within this system and while structure of vegetation communities resemble those in land units Bs2 and Bs3, species assemblages differ. Two land units exist within the Uc system, with the low hills of Uc4 occurring close to Bs3. The stony interfluves of Uc1 occur at the base of these hills and the numerous drainage channels that occur within this unit show a distinct vegetation type from the drainage channels of Bs5 (These are shown in Figure 4.1-2).
Based on survey results, eight refined vegetation communities have been mapped over the entire Project area, which is estimated at 3,800 ha. The vegetation communities present in each land unit
4.1-9 Jervois Base Metal Project
Impact Assessment and the dominant plant species present within each of these vegetation communities are shown in Figure 4.1-3
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-10
Table 4.1-2 Land systems, land units and vegetation communities present in the Project area Land System Land Unit Land Unit Description Vegetation Fine Description Dominant Species community Bond Bs2 Schist ridges forming 1 Hummock (Triodia basedowii, Acacia spondylophylla, Corymbia Springs: closely dissected tracts; Triodia pungens) grassland with apparrerinja, Triodia basedowii, Bold rocky short, rocky hill slopes, 10- sparse shrubs and low trees. Enneapogon oblongus hills, low 35%, with basal colluvial 4 Tall Acacia aneura woodland Acacia aneura, Atalaya hemiglauca, rugged aprons. over short grasses in fire Senna artemisioides ssp. helmsii, undulating protected valleys and upper Enneapogon polyphyllus, Aristida country and reaches of drainage lines. holathera narrow 2 Sparse, low Acacia siberica Acacia sibirica, Acacia aneura, plains. shrubland over short grasses and Atalaya hemiglauca, Aristida holathera, forbs. Aristida contorta, Enneapogon polyphyllus Bs3 Erosional slopes at the 2 Sparse, low Acacia siberica Acacia sibirica, Acacia aneura, foot of BS1; 1-5%. Rock shrubland over short grasses and Atalaya hemiglauca, Aristida holathera, outcrops in upper forbs. Aristida contorta, Enneapogon sectors, shallow gulling polyphyllus down slope. 1 Hummock (Triodia basedowii, Acacia spondylophylla, Corymbia Triodia pungens) grassland with apparrerinja, Triodia basedowii, sparse shrubs and low trees. Enneapogon oblongus 5 Tall, open woodland with Acacia estrophiolata, Acacia aneura, Corymbia and Acacia siberica Senna artemisioides ssp. oligophylla, over short grasses and forbs; on Enneapogon polyphyllus floodplains and at the base of ranges. Bs4 Discontinuous drainage 5 Tall, open woodland with Acacia estrophiolata, Acacia aneura, flats and basins with Corymbia and Acacia siberica Senna artemisioides ssp. oligophylla, minor tributary fans. over short grasses and forbs; on Enneapogon polyphyllus floodplains and at the base of ranges. 2 Sparse, low Acacia siberica Acacia sibirica, Acacia aneura, shrubland over short grasses and Atalaya hemiglauca, Aristida holathera, forbs. Aristida contorta, Enneapogon polyphyllus
4.1-11 Jervois Base Metal Project
Impact Assessment
Land System Land Unit Land Unit Description Vegetation Fine Description Dominant Species community 3 Acacia estrophiolata tall, open Acacia estrophiolata, Acacia aneura, woodland over short grasses Acacia tetragonophylla, Pterocaulon with sparse shrubs. sphacelatum, Cenchrus ciliaris, Themeda triandra 7 Eucalyptus camaldulensis tall E. camaldulensis, Acacia estrophiolata, woodland over sparse grasses in Themeda triandra, Cenchrus ciliaris, drainage channels and rocky Eulalia auria creek beds. 8 Acacia georginae (Gidgee) Acacia georginae, Enneapogon dominated woodland. Sparse polyphyllus, Sclerolaena bicornis grass and forb understorey. Bs5 Channels up to 30 m 7 Eucalyptus camaldulensis tall E. camaldulensis, Themeda triandra, wide and 1.5 m deep. woodland over sparse grasses in Cymbopogon ambiguous, Triodia drainage channels and rocky longiceps creek beds. 5 Tall, open woodland with E. camaldulensis, Themeda triandra, Corymbia and Acacia siberica Cymbopogon ambiguous, Triodia over short grasses and forbs; on longiceps floodplains and at the base of ranges. Sonder: So1 Cuestas; on moderately 1 Hummock (Triodia basedowii, Triodia pungens, Acacia Bold rocky to steeply dipping strata; Triodia pungens) grassland with spondylophylla, Acacia monticola, hills, low slightly bevelled, sparse shrubs and low trees. Grevillea wickhamii, Eremophila latrobei rugged So3 weathered crests. Rock 1 Hummock (Triodia basedowii, Acacia aneura, Senna artemisioides country and faces and structural Triodia pungens) grassland with ssp. helmsii, Triodia pungens narrow benches; gullied sparse shrubs and low trees. plains. escarpments and dip slopes dissected by parallel V-shaped valleys. So5 6 Sparse low Acacia woodland Acacia aneura, Acacia kempeana, over hummock grasses. Corymbia opaca, Triodia pungens
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-12
Environmental Impact Statement
Land System Land Unit Land Unit Description Vegetation Fine Description Dominant Species community Major channels up to 3 7 Eucalyptus camaldulensis tall Acacia aneura, Acacia kempeana, m deep with adjacent woodland over sparse grasses in Corymbia opaca, Triodia pungens narrow sandy flats. drainage channels and rocky creek beds. Unca: Uc1 Interfluves up to 1 km 2 Sparse, low Acacia siberica Acacia aneura, Senna artemisioides Gently wide; slightly rounded shrubland over short grasses and oligophylla, Atalaya hemiglauca, undulating stony crests and steeper forbs. Aristida holathera, Enneapogon stony plains. margins with rounded polyphyllus valley heads 3 Acacia estrophiolata tall, open Acacia estrophiolata, Acacia aneura, woodland over short grasses Acacia tetragonophylla, Pterocaulon with sparse shrubs. sphacelatum, Cenchrus ciliaris, Themeda triandra 5 Tall, open woodland with Acacia estrophiolata, Corymbia Corymbia and Acacia siberica opaca, Acacia aneura, Corymbia over short grasses and forbs; on apparrerinja, Atalaya hemiglauca, floodplains and at the base of Senna artemisioides oligophylla, Aristida ranges. holathera, Eragrostis eriopoda Uc4 Low hills. 2 Sparse, low Acacia siberica Acacia siberica, Acacia aneura, shrubland over short grasses and Atalaya hemiglauca, Enneapogon forbs. polyphyllus, Aristida holathera 5 Tall, open woodland with Acacia estrophiolata, Corymbia Corymbia and Acacia siberica opaca, Acacia aneura, Corymbia over short grasses and forbs; on apparrerinja, Atalaya hemiglauca, floodplains and at the base of Senna, artemisioides oligophylla, ranges. Aristida holathera, Eragrostis eriopoda
4.1-13 Jervois Base Metal Project
Figure 4.1-2 Land units
4.1-14 Jervois Base Metal Project
Environmental Impact Statement
Figure 4.1-3 Vegetation communities
4.1-15 Jervois Base Metal Project
Impact Assessment
Conservation significant vegetation communities An assessment of conservation significance of a site’s vegetation types can be made with reference to: • The Northern Territory Land Clearing Guidelines (NT NREAS, 2010) for vegetation regarded as “sensitive” to disturbance vegetation types (i.e. rainforest, vine thicket, closed forest or riparian vegetation, mangroves, monsoon vine forest, sand sheet heath and vegetation containing large trees with hollows suitable for fauna) • The Supplement to the NT Parks and Wildlife Conservation Masterplan (Baker, 2005) for bioregional conservation significance • Essential habitats listed under the TPWC Act or ecological communities listed under the EPBC Act; and • Previous area specific assessments by government or information to be found in the scientific literature.
A summary of significant vegetation communities within the Project area is presented in Table 4.1-3.
Table 4.1-3 Significant vegetation communities located in the Project area Significant value Description Present in Project area Area (ha) Sensitive vegetation Trees containing Central area of the 2.56 ha large trees with Project area near hollows suitable for the southern end of fauna the proposed tailings dam. Bioregional Within the Jervois The majority of the 3,350 ha Conservation Range – site of Project area (88%) is Significance botanical mapped within this significance (SoBS) area. Essential habitat n/a No 0 ha (TPWC Act) TEC (EPBC Act) n/a No 0 ha Identified as n/a No 0 ha significant in previous government assessment
Threatened Ecological Communities (TECs) Threatened ecological communities (TECs) are recognised as Matters of National Environmental Significance (MNES) protected under the EPBC Act. No listed threatened ecological communities were identified by the desktop study within the Project area and surveys did not locate any TEC on the ground.
Other vegetation (Groundwater Dependent Ecosystems(GDEs)) The understanding of, and information available for, groundwater dependent ecosystems in Central Australia is developing slowly. Eucalyptus camaldulensis (river red gum) and some Corymbia spp. are known to be dependent on groundwater. Eucalyptus camaldulensis is dependent on shallow ground water (up to 10 m bgl (Horner, 2009), whereas Corymbia species, while still tending to be groundwater dependent in semi-arid areas, are deeper rooted (8-20 m) than E. camaldulensis. Old Corymbia opaca (Bloodwood) trees may be more than 300 years old and have survived long lasting droughts in that time may also be better able to extract soil water against higher pressure deficits. These species are
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-16
Environmental Impact Statement locally common within 20 km of the Project area. Eucalyptus camaldulensis, C. opaca and C. aparrerinja were recorded throughout the Project area during on-ground surveys. The river red gums at the Jervois Dam have flourished since the dam was built in the late 1970 or early 1980 period as a source of water for the newly opened Jervois mine in 1983.
Within the Project area, generally groundwater levels are greater than 20 metres below ground level suggesting that the watertable in this location is likely to be disconnected from the regional groundwater system (Georgina Basin) (CloudGMS, 2018). However, there are two sites that show groundwater levels less than 5 m below ground level and these are associated with Unca Creek (CloudGMS, 2018). There is a moderate to high likelihood that the E. camaldulensis community along Unca Creek (north) and the major tributary to Unca Creek (south) is dependent on groundwater within the alluvial soils.
4.1.3.2 Flora species
General description A total of 196 flora species were identified from 42 families during the 2012, 2013, 2017 and 2018 surveys (Low Ecological Services P/L, 2018). These current results include two species listed as near threatened under the TPWC Act and six introduced species. The number of flora species recorded varied between on-ground surveys with the highest number recorded in September 2017 (n= 131). This is likely due to good rains prior to the survey with 53.6 mm of rainfall in July 2017, and an increased survey effort with 11 sites visited in 2017 compared with 9 sites in the 2012 and 2013 on- ground surveys.
Threatened species The NT Parks and Wildlife Conservation Act (TPWC Act) is “an Act to make provision for and in relation to the establishment of Territory Parks and other Parks and Reserves, and the study, protection, conservation and sustainable utilisation of wildlife”. Under the TPWC Act, all threatened species are protected wildlife. Within a 20 km radius of the Project area, the NT Flora Atlas (2015) database identified no threatened species listed under the EPBC Act and six species listed under the TPWC Act. Targeted searches were conducted for flora species of conservation significance listed under the TPWC Act that were identified in database searches as potentially occurring within the Project area: • Desert fuchsia (Eremophila cordatisepala) • Bolboschoenus caldwellii • Sauropus rigens; and • Sida intricate. No threatened flora species listed under the EPBC Act were recorded in the Project during on ground surveys in 1999, 2012, 2013, 2017 and 2018. Two flora species listed as near threatened under the Territory Parks and Wildlife Conservation Act (TPWC Act), Eremophila cordatisepala and Sauropus rigens, were recorded during on-ground surveys (Figure 4.1-4). Error! Reference source not found. Figure 4.1-4 Floristic Values of Conservation Significance
4.1-17 Jervois Base Metal Project
Impact Assessment
The Eremophila cordatisepala in the Project Area is the western most population of the species distribution in the Channel Country bioregion. One species listed as endangered under the TPWC act, Bolboschoenus caldwellii, has a low-moderate likelihood of occurring in the Project area. Two additional species listed as data deficient under the TPWC Act have a high likelihood of occurring in the Project area; Fimbristylis velata and Sida sp. Hale River; due to the proximity of nearby records and the presence of potential habitat. Both species are associated with moist areas, such as waterway or wetlands, and their presence or absence may be dependent on the availability of water. One additional species listed as data deficient under the TPWC Act has a low likelihood of occurring in the Project area; Amaranthus centralis, has a low likelihood of occurring in the Project area.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-18
Table 4.1-4 Threatened and conservation significant flora species identified as occurring or potentially occurring within a 20 km radius of the Project area Scientific name Status Preferred habitat Likelihood of occurrence in Project area Source
EPBC Act EPBC TPWA PMST NT Flora Atlas Amaranthus centralis - DD Native to NT and recorded from several Unlikely: There is one record at Anatye X bioregions: Burt Plain, Central Ranges, on the side of the Plenty Highway, Channel Country, Finke, MacDonnell approximately 15 km south-east of the Ranges, Pilbara, Simpson Strzelecki Project area. Given the dry and open Dunefields and Tanami. Occurs on fertile sparse shrubland habitats of the Project alluvial plains and valleys, sandplains, area, the species is considered unlikely to rocky or gravelly hills or rises composed of occur. neutral, acidic or basic rocks, and intermittent watercourses and run-on areas (Northern Territory Herbarium, 2013).
Bolboschoenus caldwellii - E In the NT, B. caldwellii is only known from Possible: The record of B. caldwellii on X five isolated populations, all ephemeral Jervois Station is 3.4 km west of the wetland areas. One site within Finke Gorge Project area at Valley bore and is dated National Park, two sites south of Finke 1985. It has not been confirmed whether Gorge, Ilparpa swamp sewerage outflow this population still exists. The desktop and at a bore overflow on Jervois Station survey found there may be suitable (White, Plant species and sites of botanical habitat for the species in the vicinity of significance. Volume 1: Significant sites. the Jervois Dam and at operational bore Part 1: Sites of significance,, 2000). The overflow areas. If present, the species Finke Gorge National Park population is may only be detected after rains when now presumed extinct (Kerrigan, 2006). the soil is moist. Given the availability of According to (Kerrigan, 2006), the suitable habitat and its ephemeral and populations of B. caldwellii on Jervois disjunct distribution in the NT, there is a Station and at Ilparpa Swamp are low likelihood of the species occurring in presumably from propagules transported ephemeral wetland areas in the Project by birds and are considered ephemeral area. populations expected to disappear as availability of water ceases. The species
4.1-19 Jervois Base Metal Project
Impact Assessment
Scientific name Status Preferred habitat Likelihood of occurrence in Project area Source
EPBC Act EPBC TPWA PMST NT Flora Atlas occurs in damp soils adjacent to permanent or semi-permanent water (Kerrigan, 2006).
Fimbristylis velata - DD Fimbristylis velata flowers in spring-summer Likely: This species has been recorded X and grows in moist areas. Occurs in all within the Project area in the Sonder land States of Australia except Tasmania system. (Northern Territory Government, 2018). Sida sp. Hale River - DD Native to the Northern Territory and known Likely: This species has been recorded in X from Burt Plain, Channel Country and Channel Country and appropriate MacDonnell Ranges bioregions. Occurs habitat occurs in the Project area. near watercourses on sheltered rocky or gravelly slopes composed of neutral, acidic or basic rocks (Northern Territory Government, 2018).
Sida intricata - NT The species is widespread across all states Likely: The closest record of S. intricata X of mainland Australia but is less common in identified in the NT Herbarium database NT (Australian Virtual Herbarium, 2017). The extract is approximately 13 km north-east species occurs across a wide range of of the Project area, dated 1957. This habitats (Atlas of Living Australia, 2017). record is an outlier from the main population occurring around Alice Springs. Due to the close proximity of the record in the NT Herbarium extract and the fact that the species occurs in a wide variety of habitats, there is a high likelihood of S. intricata occurring in the Project area.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-20
Environmental Impact Statement
Scientific name Status Preferred habitat Likelihood of occurrence in Project area Source
EPBC Act EPBC TPWA PMST NT Flora Atlas Sauropus rigens - NT The species is described as rare in the NT Known: The database search identified X (White, 2000)and occurs in the Channel two records of S. rigens within the 20 km Country Bioregion and the MacDonnell buffer of the Project area. These are 6 km Ranges Bioregion. Sauropus rigens occurs and 14 km north, both within the Jervois on rocky sandstone ranges or hills, typically Range. Recorded on skeletal soils on on dry steep slopes with Acacia sp. holey steep sandstone ranges and slopes of trunk or with Acacia georginae, A. the Jervois Range in 2017 and found cyperophylla and A. sibirica as overstorey commonly on the steep rocky cliffs by dominants (Northern Territory Herbarium, the dam in 2018. 2013). Eremophila cordatisepala - NT The species is endemic to the channel Known: The NT Herbarium database X country in QLD and NT. The species has identified a record of E. cordatisepala 6 been found widely distributed in the km north of the Project Area in the Jervois calcareous soils north of the Jervois range range. Records in the Project area are at at the south of the Project area. the western distribution limit of this species (White, 2000). Recorded on undulating calcareous plains with low open woodland in 2012, 2013, 2017 and 2018. Quite widely distributed in the Project area.
4.1-21 Jervois Base Metal Project
Taxa of bioregional significance
Taxa of bioregional significance for the Channel Country bioregion (in which the Project is located) is listed for Jervois Range ‘Sites of Botanical Significance’ (White, Albracht, Daguid, Latz, & Hamilton, 2000). It includes: • Abutilon cryptopetalum (apparently rare and only known in Channel Country from this site) • Chrysopogon pallidus (disjunct and only known in Channel Country from this site); and • Pandorea doratoxylon (eastern range limit and only known in Channel Country from this site).
None of these bioregionally significant species were located in the Project area during field surveys.
Other taxa only known in Channel Country bioregion (NT portion) from Jervois Range (White, Albracht, Daguid, Latz, & Hamilton, 2000), include: • Acacia monticola • Acacia spondylophylla • Cheilanthes brownii • Cyperus cunninghamii • Eragrostis cumingii • Eremophila duttonii • Eucalyptus intertexta • Eucalyptus normantonensis • Ficus brachypoda • Glossostigma diandrum • Grevillea wickhamii subsp. aprica • Lysiana subfalcata • Olearia stuartii • Schoenoplectus litoralis • Sida ammophila; and • Tribulus macrocarpus.
Of the above listed taxa that are limited to the Jervois Range within the Channel Country, three species were noted in the Project area: Acacia monticola, Acacia spondylophylla and Eragrostis cumingii. These species are found in abundance in other bioregions.
Introduced flora The Weeds Management Act 2001 is administered by the NT Department of Environment and Natural Resources (DENR). The objective of the Weeds Management Act is to prevent the spread of weeds within, into and out of the NT and to ensure that the management of weeds is an integral component of land management. The Act is linked to the Northern Territory Weeds Management Strategy 1996- 2005, which led to a series of Statutory Plans being developed for each declared weed. ‘Declared weeds’ are grouped into three categories: • Class A - weeds to be eradicated • Class B - weeds which growth and spread must be controlled; and • Class C -weeds not to be introduced to the Territory.
Weeds of National Significance (WoNS) are declared based on invasiveness, potential for spread, and environmental, social and economic impacts. Strategic plans for control of WoNS are developed as a result of their declaration, which define responsibilities and identifies strategies and actions to control
4.1-22 Jervois Base Metal Project
Environmental Impact Statement the species. Landholders and managers are ultimately responsible for managing WoNS, and the state/territory government is responsible for overall legislation and administration (DSEWPC, 2012) Six introduced flora species were recorded during the on-ground surveys, including: • Buffel grass (Cenchrus ciliaris) • Coral cactus (Cylindropuntia fulgida var. mamillata) – WoNS, Class A & C • Couch grass (Cynodon dactylon) • Spiked Malvastrum (Malvastrum americanum) • Athel pine (Tamarix aphylla) – WoNS, Class A & B; and • Prickly mimosa (Vachellia farnesiana).
Some of these species were widespread in the Project area, like buffel grass. Other species were more restricted in distribution. Tamarix aphylla (athel pine) was found around the old mine village and is a Weed of National Significance (WoNS) and declared Class A (to be eradicated) and Class C (not to be introduced to the NT) weed in the NT. Cylindropuntia fulgida var. mamillata (coral cactus) was also found around the old mine village and is a WoNS and declared a Class A weed in the NT. This population of coral cactus has since undergone a control program and only one dead specimen and a number of juvenile specimens were located on the Project area in 2017 surveys. In 2018 surveys no new specimens were located and it appears that the control program has been successful.
4.1.3.3 Sites of Conservation Significance (SoCS) SoCS are sites identified as important sites for biodiversity that need protecting. In the Northern Territory (NT) there have been 67 sites identified as the most important sites for biodiversity conservation that need further protecting. There are no SoCS within 20 km of the Project area.
4.1.3.4 Sites of Botanical Significance (SoBS) SoBS are defined as area that have botanical features distinguishing them from the surrounding landscape, and that are important for general plant conservation but specifically for the association of species in the area (White, Plant species and sites of botanical significance. Volume 1: Significant sites. Part 1: Sites of significance,, 2000). The majority (88%) of the Project area exists within the Jervois Range SoBS. The Jervois Range SoBS encompasses the isolated sandstone and siltstone Jervois 2 Range and surrounding footslopes, an area of approximately 274km (White, Plant species and sites of botanical significance. Volume 1: Significant sites. Part 1: Sites of significance,, 2000). Known taxa of NT significance in this bioregion include Bolboschoenus caldwellii, Eremophila cordatisepala, Fimbristylis velata and, Sauropus rigens, three of which species require long term soil moisture to survive (White, Plant species and sites of botanical significance. Volume 1: Significant sites. Part 1: Sites of significance,, 2000). Land use within this SoBS is Pastoral - Jervois Station (85% of the Jervois Range SoBS) and Lucy Creek Station (14% of Jervois Range SoBS). The Jervois SoBS is defined mainly on the outlier presence of several species of ground plants, two dependent on wetland situations, and two, primarily data deficient species, at the extreme of their ranges.
4.1.5. Potential Impacts and Risks The construction and operation of the mine is associated with a number of potential impacts to the floristic values of the Project area, including: • Vegetation clearing for pits and infrastructure • Impacts to threatened flora • Introduction of exotic flora
4.1-23 Jervois Base Metal Project
Impact Assessment
• Dust pollution • Erosion and sedimentation • Changes in hydrology • Release of contaminants (including from tailings dams and waste rock); and • Bushfire.
A risk assessment process has been undertaken to predict the level of risk associated with each impact (Appendix C-11). The process follows the procedures described in AS/NZS 4360 (1999) and ISO 31000 (2009) and has been undertaken for each impact before the application of any mitigation measures. The application of mitigation measures will ameliorate the level of risk to an acceptable level for the Project.
4.1.5.1 Vegetation clearing for pits and infrastructure The total disturbance footprint for the Project will be approximately 970 hectares (ha), of which approximately 163 ha has been previously disturbed by historic mining activities. In accordance with the Vegetation Survey of the Northern Territory (Wilson, 1990) the entire impact area is within the Acacia woodland broad vegetation classification. At a finer scale the impact area affects two fine vegetation classes Class 71 (Acacia aneura (Mulga) tall sparse-shrubland with grassland understorey) and Class 74 (A. stowardii (Bastard Mulga), Cassia, Eremophila (Fuchsia) sparse-shrubland). Both of these fine vegetation classes have <1% of their extents protected within reserves in the Northern Territory (Baker, 2005). The areas impacted by the Project represent <0.1% of that in the Northern Territory and < 0.05 % of the Acacia woodland broad vegetation class within the Channel Country Bioregion.
The vegetation community most affected by the Project would be vegetation community 5 – Corymbia and Acacia sibirica woodland. This is a reflection of it’s distribution over the Project area. The entire impact area is located within the Jervois Range, which is a Site of Botanical Significance (SoBS). Table 4.1-5 contains details of the impact of the Project on each of the vegetation communities located within the Project area, including conservation significant vegetation communities (identified by the ecological survey). RISK ASSESSMENT RATING: medium (before mitigation)
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-24
Environmental Impact Statement
Table 4.1-5 Vegetation communities impacted by the Project Flora value Description Impact Amount in Amount in (ha) Project NT (ha) area (ha) Mapped vegetation (fine vegetation classes) Class 71 Acacia aneura (Mulga) tall sparse- 4.9 1,400 1,514,750 shrubland with grassland understorey Class 74 A. stowardii (Bastard Mulga), 192.2 2,400 163,080 Cassia, Eremophila (Fuchsia) sparse-shrubland Surveyed vegetation communities (Low Ecological Services P/L, 2017) 1 Hummock (Triodia basedowii, 14.24 345.7 Triodia pungens) grassland with sparse shrubs and low trees. 2 Sparse, low Acacia siberica 107 1,266 shrubland over short grasses and forbs. 3 Acacia estrophiolata tall, open 0.15 127.5 woodland over short grasses with sparse shrubs. 4 Tall Acacia aneura woodland over 2.46 23.8 short grasses in fire protected valleys and upper reaches of drainage lines. 5 Tall, open woodland with 69.9 1,843 Corymbia and Acacia siberica over short grasses and forbs; on floodplains and at the base of ranges. 6 Sparse low Acacia woodland over 0 55.23 hummock grasses. 7 Eucalyptus camaldulensis tall 3.35 123.2 woodland over sparse grasses in drainage channels and rocky creek beds. 8 Acacia georginae (Gidgee) 0 11.32 dominated woodland. Sparse grass and forb understorey. Conservation significant vegetation communities Sensitive Mature bloodwood and ironwood 2.56 2.56 vegetation woodland containing large trees with hollows suitable for fauna. Bioregional Within the Jervois Range – site of 197.1 3,350 27,500 Conservation botanical significance (SoBS) Significance
4.1-25 Jervois Base Metal Project
Impact Assessment
4.1.5.2 Impacts to threatened flora
Two flora species listed as near threatened under the Territory Parks and Wildlife Conservation Act (TPWC Act), Eremophila cordatisepala and Sauropus rigens, were recorded during on-ground surveys
There are six records of E. cordatisepala from the Project area in association with Corymbia and Acacia sibirica woodland (4 records) and Acacia estrophiolata woodland (2 records) and all are outside the proposed extent of disturbance for new mine infrastructure and pits. One record is within 10m of the existing Marshall Reward Pit access road and another two records are within 30m of existing Lucy Creek Station Road (in the south of the Project area) and these specimens may be subject to indirect impacts from dust deposition.
The S. rigens was located in Hummock grassland habitat on the western side of the Project area. There are two records from the Project area and both are outside the proposed extent of disturbance. However, it is noted that one record is located approximately 90m east of Jervois Dam and any future works on the dam will need to consider management for the species.
RISK ASSESSMENT RATING: medium (before mitigation)
4.1.5.3 Introduction of exotic flora The current assessment has recorded the presence of a variety of exotic flora, including two declared weeds and WoNS species as follows: • Buffel grass (Cenchrus ciliaris) • Coral cactus (Cylindropuntia fulgida var. mamillata) – WoNS, Class A & C • Couch grass (Cynodon dactylon) • Spiked Malvastrum (Malvastrum americanum) • Athel pine (Tamarix aphylla) – WoNS, Class A & B; and • Prickly mimosa (Vachellia farnesiana).
Exotic flora species are concentrated in areas suffering some form of disturbance, mostly clearing for cattle grazing. Weeds threaten populations of native flora and fauna by competing with native flora and eventually changing the habitat, which is no longer suitable for the majority of native species. The EPBC Act lists weed invasion as a ‘key threatening process’ to biodiversity due to the impact on wildlife and the landscape (Threatened Species Scientific Committee (TSSC), 2009).
The spread of weed species is facilitated by disturbance. During construction there would be the potential for disturbing weeds in the Project area resulting in the movement of weeds within and outside of the Project area. This could increase the level of infestation in the Study area and potentially facilitate the spread of weeds to the other adjacent areas. Weed seed can be transported in the mud on machinery or in the machinery itself.
There is a low likelihood of weeds spreading into adjoining native woodland/forest vegetation as a result of the Project because the control of declared weeds will be implemented for the Project area. Further, construction areas and the post-mine landforms will be progressively rehabilitated with native vegetation (limiting opportunities for weeds to grow).
RISK ASSESSMENT RATING: medium (before mitigation)
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-26
Environmental Impact Statement
4.1.5.4 Dust pollution
Dust deposition from passing haul trucks may impact on natural ecosystems adjacent to the Project area if reasonable quantities of dust are sustained over extended periods of time. Excessive dust deposition on foliage can reduce photosynthetic processes, respiration, transpiration and subsequent growth rate of the plant (Farmer, 1993) (Thompson, Mueller, Fluckiger, & Rutter, 1984). There are some studies that suggest that dust deposition on foliage may allow the penetration of phytotoxic gaseous pollutants, subsequently affecting the health of the plants (Farmer 1993). Research on vegetation response to dust deposition impact (Doley, 2003) has shown that for sunny conditions a dust deposition rate of up to 15 g/m²/month (or 500 mg/m²/day) is unlikely to have a detectable effect on plant growth and it is not until a deposition rate of up to 30 g/m²/month (or 1,000 mg/m²/day) occurs that there is a measurable reduction in plant growth under overcast conditions.
Dust deposition issues are most likely to occur along haul roads, where there is a narrow corridor with natural areas or publicly accessible areas immediately adjacent to activities involving heavy machinery and the transportation of ore. Activities within the mine (i.e. open mine pits and waste piles) would also create dust, but these issues would be created and managed within the mine disturbance area and are less likely to spill over into adjacent natural areas.
RISK ASSESSMENT RATING: medium (before mitigation)
4.1.5.5 Erosion and sedimentation Erosion is the transport by wind, water and ice of soil, sediment and rock fragments produced by the weathering of geological features (Department of Water and Environmental Regulation (DWER), 2018). Sedimentation occurs when eroded material that is being transported by water, settles out of the water column onto the surface, as the water flow slows (Department of Water and Environmental Regulation (DWER), 2018). The Project has the potential to impact on water quality in Unca Creek and
4.1-27 Jervois Base Metal Project
Impact Assessment its tributaries due to controlled and uncontrolled releases of sediment laden water. The vegetation clearing and surface disturbance associated with the construction and operation of the Project can lead to increased run-off, erosion of exposed surfaces and ultimately sedimentation of the waterways. This can impact on native vegetation communities. For example, increased run-off can lead to higher velocities in waterways during rainfall, eroding the banks in areas where riparian vegetation is sparse (Department of Water and Environmental Regulation (DWER), 2018) and in some cases, undermining existing vegetation (e.g. causing instability of mature trees).
Sedimentation in downstream areas (where the velocities are lower) can lead to filling of the waterway channel and encroachment of the riparian vegetation into the waterway channel (Department of Water and Environmental Regulation (DWER), 2018). The vegetation in these areas of encroachment is often weedy and does not represent the surrounding natural ecosystems. Large sediment accumulations can cause upstream flooding, or deflect the flow into the adjacent stream bank or even onto adjacent land, causing further erosion (Department of Water and Environmental Regulation (DWER), 2018).
The proposed Jervois Dam upgrade will increase peak discharges, flood levels and velocities in Unca Creek downstream of the dam due to the increased spillway capacity. The predicted increases in flood levels and velocities are typically confined to the Unca Creek channel. The increased levels and velocities would be no greater than pre-dam levels and velocities, and therefore the impact is not predicted to change the morphological behaviour of Unca Creek (WRM Water & Environment P/L, 2018).
There are three sediment catchment dams planned for the Project: two on Unca Creek (associated with the Reward waste rock dump) and one on a tributary of Unca Creek for the Bellbird waste rock dump (both near the Lucy Creek Station Road crossing). These dams are intended to prevent any sedimentation from the Project site travelling to downstream areas. The dams will be part of a broader Erosion and Sediment Control Plan (ESCP) developed for the Project.
Further detail on erosion and sedimentation is included in the Surface Water and Geology Sections of the EIS.
RISK ASSESSMENT RATING: high (before mitigation)
4.1.5.6 Changes in hydrology The hydrological landscape of an area greatly influences the distribution and type of vegetation communities found there. The impacts of hydrological change may include redirection or drainage of water away from a water dependent ecosystem or flooding of normally dry areas. These changes are ultimately expressed by the vegetation communities, which may die-back or expand into new areas. The remaining areas of vegetation (outside of the disturbance zone) would be vulnerable to alterations in the hydrological landscape.
Diversion of Unca Creek The proposed Reward pit is located within the channel and floodplain of Unca Creek and would be affected by Unca Creek floodwaters. It is proposed to construct a permanent diversion of Unca Creek around the Reward pit. The proposed diversion was designed as a trapezoidal channel with a base width of 30 m and batter slopes of 1V:5H. The diversion was sized to convey the 0.1% AEP discharge from the catchment upstream of the Reward Pit under operational conditions (incorporating the raised Jervois Dam spillway). The diversion will be deepest (about 9.9 m) at its middle section where it crosses the ridge line north of the Reward Pit. Bunds are also required at several locations along the
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-28
Environmental Impact Statement diversion to prevent water overflowing from the diversion into the pit. The final landform between the Reward pit and the creek diversion will ensure that the final void is protected from inundation for all flood events up to and including the Probable Maximum Flood (PMF) event (WRM Water & Environment P/L, 2018). The Unca Creek diversion will remain in place as part of the final landform. The final landform for the Project will ensure that the remnant surface water catchments that drain into the final voids are limited to the voids themselves and therefore the stored water cannot overflow to impact on surface water (WRM Water & Environment P/L, 2018).
Flooding The proposed upgrade to Jervois Dam (increased spillway level) will result in an increase in the area inundated by the lake behind the dam wall. The water balance model was used to investigate the impact of the dam upgrade on lake water levels. The area of inundation at full supply will increase from about 16 ha under existing conditions to about 36 ha under the upgraded dam case. The increased inundation extent does not affect any existing structures or sensitive environmental or cultural heritage areas. The potential impacts of the increased inundation extent and frequency are not considered to be significant. However, the mine closure plan for Jervois Dam could include the upgraded dam remaining in place, reduction in spillway level to the pre-mining level, or complete removal of the dam, depending on whether maintaining the dam is beneficial to the post-mining landholder.
Water Balance The water mass balance shows the Process Plant is projected to require a constant water demand rate of 86.1 T/h (2.05 ML/d) over the life of the Project (WRM Water & Environment P/L, 2018). Other water demands include dust suppression (approximately 1,500 ML/yr), underground mining (12 – 37 ML/yr). Water supply will be achieved from three main sources: 1. The Water Management System Infrastructure designed for the Project aims to collect and reuse mine affected water (e.g. run-off from process plant, pit areas) and raw water unsuitable for consumption (e.g. groundwater seepage to underground and open cut mines, waste rock run-off) within the mines process plant. Process water will be recycled from thickeners in the process plant and the decant water return from the TSF and topped up from raw water as required. There will be a Process Water Pond for temporary storage and duty/standby pumps will be installed to supply process water to all areas of the plant. If insufficient mine affected or sediment laden water is available to supply the process water demand to the plant, raw water will be used to supply the plant demand (WRM Water & Environment P/L, 2018) 2. Raw water (potable standard and plant standard) will be supplied from Jervois Dam - the existing dam will undergo repairs to minimise water losses and maximise water recovery, as it will be used as a priority over the use of bore water. 3. A borefield will be established external to the Project area to provide raw water (potable standard). CloudGMS (2018) proposes a borefield capable of producing up to 2,000 ML/year for 10 years. Bores will be completed into the Georgina Basin Carbonate Aquifer at a site 10km to the north of the mine site. The extraction is within the capacity of the aquifer and removes a very small fraction of the immense volume in storage. Water table drawdown impacts at the nearest sensitive receptors (Lucy Creek domestic water supply and stock watering bores) are unlikely to exceed 3 m (CloudGMS, 2018). This drawdown will not reduce water availability for these user’s due to the very significant available drawdown at each site. There are no mapped Groundwater Dependant Ecosystems identified within the zone of drawdown.
4.1-29 Jervois Base Metal Project
Impact Assessment
The performance of the water management system (WMS) was assessed using the OPSIM water balance model (WRM Water & Environment P/L, 2018). OPSIM is a computer-based operational simulation model that has been developed to assess the dynamics of the water balance under varying rainfall and catchment conditions throughout the development of the Project. The average external water supply requirements vary over the life of the Project. The following is of note: • External water supply (from the borefield) requirement is largest at the start of the Project (EOY0), reducing significantly towards EOY6 in conjunction with the increasing availability of groundwater from the underground mines to meet site demands. External water supply increases from EOY6 to EOY10 as groundwater inflows to the underground mines decrease from EOY6 to EOY10 • The average annual raw water supply requirements from Jervois Dam varies between 1 and 174 ML/yr over the life of the Project. – with the highest requirement from EOY0 to EOY5 and again from EOY7 to EOY10 • The average annual external raw water supply requirements from the groundwater bore fields varies between 20 and 1,353 ML/yr over the life of the Project – with the highest requirement from EOY0 to EOY5; and • A deficit in the water supply of 1 to 2 ML/yr is high-lighted in the model between EOY0 and EOY6, and a deficit of 40 ML/yr is shown in EOY7-8. This is a relatively small deficit that may be managed by limiting dust suppression activities, as necessary.
The water balance model was used to assess the change in flows in Unca Creek immediately downstream of the dam following the upgrade (WRM Water & Environment P/L, 2018). The following is of note: • Under existing conditions, Jervois Dam is predicted to overflow via the spillway on approximately 0.8% of all days. That is, there is no flow over the spillway 99.2 % of the time • Under year 1 conditions (upgraded dam and site demands sourced from the dam), the dam is predicted to overflow only 0.1% of the time. That is, there would be no flow over the spillway for 99.9 % of the time • Under the post mine closure scenario (upgraded dam and no site demands), the dam is predicted to overflow about 0.15 % of the time. That is, there would be no flow over the spillway for 99.85 % of the time; and • The maximum predicted daily flow over the spillway is increased by about 500 ML/day for both of the upgraded dam cases due to the more efficient and larger spillway proposed as part of the upgrade.
It should be noted that the existing dam has already altered the streamflow regime of Unca Creek significantly. Further, the dam is situated in an arid catchment, where it would not be unusual for the dam not to overflow for several years. Water balance modelling indicates that the existing dam on average only overflows in every fourth year. The upgraded dam is predicted to overflow on average every 11 years under the year 1 scenario, and every 9 years under the post-mine closure scenario.
The cumulative impacts of water extraction on the floristic values of the Project area will be most evident in those vegetation communities that rely more heavily on the availability of water. In the Project area these areas are represented by vegetation community 7 - Eucalyptus camaldulensis tall woodland over sparse grasses in drainage channels and rocky creek beds. This community is present along Unca Creek (in the north of the Project area) and the tributary to Unca Creek (central to the Project area). Insufficient flows in the Unca Creek and it’s tributaries, combined with the extraction of groundwater, may cause dieback of the existing riparian communities. The dieback of the riparian
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-30
Environmental Impact Statement vegetation may cause bank instability in the long term and contribute to erosion and sedimentation in the Unca Creek system.
The proposed Jervois Dam upgrades will alter the streamflow regime in Unca Creek downstream of the dam, with reduced frequency of spill events, but increased maximum spill rates. The change in streamflow regime will have a significant affect along the reach of Unca Creek within the Project area, up until the Unca Creek tributary confluence (about 1km east of the Project area) which doubles the Unca Creek catchment; hence the impacts downstream of this point will be insignificant (WRM Water & Environment P/L, 2018). Although the surface water impact assessment (WRM Water & Environment P/L, 2018) has indicated that the Project will cause a significant change in the streamflow regime from the current conditions, it is unlikely that this will have a noticeable impact on the riparian vegetation (vegetation community 7) because of the historical streamflow alterations to the catchment made by Jervois dam in the 1980’s. That is, it is likely that the Unca Creek system in the Project area has been running at a deficit from a surface water perspective for approximately 38 years already.
The E. camaldulensis community in the Project area has been demonstrated to rely on surface water and shallow groundwater (up to 10m below ground) (Horner, 2009). In this case, it is likely there is a strong groundwater influence because Unca Creek flows (on average) only once in 4 years and has done so since about the 1980’s when Jervois Dam was constructed (WRM Water & Environment P/L, 2018). The groundwater levels in the Project area will be influenced by pit dewatering, particularly of Reward pit (which is located on Unca Creek). The Reward pit will intercept the water table. The groundwater impact assessment (CloudGMS, 2018) indicates that in the short-term (for the life of the mine) seepage through the mine walls will be minimal due to the low yield and flow rates of the water table in this area.
In the long-term (post-mine closure) the evapotranspiration rate in the pit lakes will exceed the seepage rate (by about five times) (CloudGMS, 2018). Groundwater drawdown is expected to occur at Reward pit and models predict that during operation the drawdown at Unca Creek (Obs 7) will be over 120 m and between 40 m and 80 m in areas about 200m from the creek line (including those areas where the creek diversion will run). Post-mining groundwater drawdown (at the point where Unca Creek meets the Reward pit) will recover very slowly and is not predicted to level out for about 180 years when it reaches levels that are still 18 - 23 m below existing levels (CloudGMS, 2018). The existing level of groundwater at Unca Creek is between 5m and 10m below ground, which means it is readily accessible to the Unca Creek GDE. GDE’s typically require groundwater levels at 20m or above. Therefore a permanent drawdown of 18 – 23m below current levels will mean that groundwater is not accessible to the GDE in the vicinity of the Reward pit and that the GDE in this area will suffer from dieback. The drawdown contours indicate that this is only a localised impact extending approximately 500m from the Reward pit (CloudGMS, 2018). From an ecological perspective this will likely result in a permanent 1 km severance of the Unca Creek riparian habitat and wildlife corridor and refuge habitat area.
RISK ASSESSMENT RATING: high (before mitigation)
4.1.5.7 Release of contaminants The potential for the release of contaminants into the environment will be generated by storage of chemicals and fuel within the Project area and activities involving the extraction of ore (pit dewatering), its subsequent processing at the mine site (tailings from crushing and beneficiating the ore) and storage of waste rock. The Water Management System Infrastructure designed for the Project aims to collect and reuse mine affected water (e.g. run-off from process plant, pit areas) and raw water
4.1-31 Jervois Base Metal Project
Impact Assessment unsuitable for consumption (e.g. groundwater seepage to underground and open cut mines, waste rock run-off) within the mines process plant. Surface run-off from undisturbed areas will be diverted around disturbed areas and released to the environment.
Potentially hazardous material Storage of chemicals will occur in the Project area for use in the processing plant, workshops, the laboratory, sewage treatment systems, a 12 MW diesel and/or gas fired power station and an explosive magazine. The use of chemicals and hydrocarbons in the Project area means that some potentially hazardous waste materials (defined in the Waste Management and Pollution Control (Administration) Regulations 2014) will be created on site. There is potential for chemical spills to occur within the Project area, impacting nearby ecosystems and causing scalding or dieback of native vegetation.
The capacity for any single spillage to impact the natural environment will be affected by the type of contaminant; and the size and location of the spill. For example, any uncontrolled release of contaminant into a waterway is likely to result in a larger impact area as the contaminant travels along the riparian system. This has been identified as a medium risk for the Project. Appropriate storage, handling and disposal of potentially hazardous material is discussed in detail in the Waste (non- hazardous) Management Plan in Section 5 of this EIS.
Tailings and waste rock Geochemical testing results show waste rock materials will comprise mainly NAF material, accounting for approximately over 80% of the waste rock materials. A smaller portion of PAF (including PAF-LC and NAF-HS) materials occur mainly within a halo around the sulphidic ore and should be readily visually identified, with S a good discriminator. Testings also indicated significant lag times before acid conditions develop after exposure to atmospheric oxidation. Longer lag times would provide flexibility in management of waste rock seepage during any temporary storage or short-term exposure during operations.
Sulphidic waste rock material show strong enrichment in a variety of metals/metalloids including Ag, Bi, Be, Cd, Co, Cs, Cu, Mo, Pb, S, Se, Tl, W and Zn with enrichment increasing with proximity to ore. A number of samples were also enriched in Fe and Mn, and individual samples were enriched in As, Ag, As, Bi, Cd, Cu, Hg, Pb, Sb, Se, Tl and Zn.
Geochemical testing results suggest that tailings from sulphide ore samples will have moderate S values of around 1% S, and are likely to be PAF. Tailings showed enrichment in a similar suite of metals/metalloids as the waste rock and ore, including Ag, Bi, Be, Cd, Co, Cs, Cu, Fe, Mn, Pb, S Mo, Se, Tl, W and Zn. Some mobilisation of Cd, Co, Cu, SO4, Mn and Zn can be expected during the lag period.
Storage of waste rock Waste Rock Landforms will be developed adjacent to each open pit. Waste rock from underground mining will be disposed of preferentially in underground voids rather than disposed of on the surface. Waste rock where suitable will be used for construction purposes such as construction of embankments for the TSF. Waste rock with favourable characteristics will be separately stockpiled for use in project closure related activities. Sediment dams will be constructed to capture and manage runoff from waste rock dumps. Most waste rock from pit and underground development is expected to be NAF and environmentally benign, and will not require specific management for control of AMD. The smaller portion of PAF material will be selective handled, including:
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-32
Environmental Impact Statement
• In pit or underground disposal below recovery water table levels • Selective underground disposal of PAF as part of paste backfill; or • Construction of an infiltration control cover system in-pit or ex-pit.
Contingency for treatment during operations include dump surface limestone addition and/or blending to help delay onset of acid drainage, and/or collection of seepage/runoff and treatment. The water balance model indicates that there is approximately a 10% chance of uncontrolled releases of water from the waste rock sediment dams in the first four years of Project life (WRM Water & Environment P/L, 2018).
Tailings Storage Facility (TSF) The TSF has been designed in accordance with design criteria applicable to this category drawn from the ANCOLD “Guidelines on Tailings Dams”. The tailings storage facility will consist of two cells and will be constructed using mine waste and local borrow. The basin area will have a composite liner to achieve an appropriate level of seepage control. The low permeability compacted composite liner comprising HDPE and soil liner will be located below the operating supernatant pond. A basin underdrainage system will be incorporated to reduce seepage, increase tailings densities and improve the geotechnical stability of the TSF. The underdrainage system drains by gravity to a collection tower located at the lowest point in the TSF basin. Supernatant water will be removed from each cell of the TSF via a central decant tower abstraction system. Solution recovered from the decant system will be pumped back to the plant for re-use in the process circuit. The active tailings beach will be regularly rotated to promote de-watering of the tailings.
Based on the above analysis it is predicted that only a small percentage of the waste rock has the potential to release harmful contaminants to the environment. In any case, the treatment of waste rock and tailings will provide for the protection of the environment from contamination. Although management will be in place to prevent the release of contaminants into the surrounding environment, in the event that uncontrolled overflow is experienced from the pits, waste rock storage areas or tailings dams, the receiving environment would be the Unca Creek tributary and Unca Creek. The results of the water balance model show that no uncontrolled releases are predicted from the process water dam in any of the water balance model simulations. Therefore, the Project will not release any mine affected water or dewatered groundwater to the environment (WRM Water & Environment P/L, 2018). This is identified as a medium risk in the Project risk assessment. RISK ASSESSMENT RATING: medium (before mitigation)
4.1.5.8 Bushfire A fire starting in the Project are may be caused by sparks originating from machinery, or an accident (such as a collision), scheduled burns getting out of control, hot works, spontaneous combustion of chemicals or explosives, or from operators and personnel dropping matches or cigarette butts in the Project area, which may then cause fires that expand into the surrounding area.
The Project is not likely to increase the potential for bushfires to occur within the surrounding landscape given the mitigation and management measures which will be implemented for the Project. Bushfire management will include clearing restrictions, restricted vehicle movements, fire breaks, the use of diesel vehicles, prohibition of smoking in fire prone areas and rapid response to any outbreak of fire.
RISK ASSESSMENT RATING: Medium (before mitigation)
4.1-33 Jervois Base Metal Project
Impact Assessment
4.1.6. Mitigation measures The mitigation strategy for the Project has focused on a hierarchy of: 1. Avoidance 2. Minimisation 3. Mitigation; then 4. Offset residual impacts. The avoidance or minimisation of adverse impacts is most relevant to the design phase of the Project, where information collected through desktop analysis and field surveys can be incorporated into the planning and preliminary engineering work. Mitigation of impacts (including the implementation of monitoring and management plans) is most relevant to the construction and operational phases of the Project. Table 4.1-6 provides a summary of the mitigation strategies for the Project, with a brief description of potential impacts and measures that can be implemented at each stage in the life of the Project. Residual impacts, after the implementation of the mitigation strategy, may be required to be offset in accordance with Commonwealth and State approval conditions. Offsets proposed for the Project are discussed in Section 4.1.8.
The Project area covers approximately 3,800 ha. The total disturbance footprint for the Project will be approximately 970 ha, of which approximately 163 ha has been previously disturbed by historic mining activities. The Project will make use of existing infrastructure as far as possible, to reduce the development footprint. The majority of new infrastructure to be located on the existing infrastructure footprint may include: • Mine pits • Roads and access tracks • Jervois Dam and spillway
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-34
Environmental Impact Statement
• Processing plant & infrastructure • Tailings Storage Facility (TSF) • Waste rock dumps • ROMs; and • Accommodation village.
Impact mitigation associated with the Project has been detailed in Table 4.1-6. Due to the length of time that the mine is expected to operate and the ongoing need for management of terrestrial flora during the operation of the mine, operational mitigation measures are best presented in Section 4.1.6.
4.1-35 Jervois Base Metal Project
Table 4.1-6 Impact mitigation Potential Impact Mitigation measures Construction & Operation Relevant Management Plans 1. Clearing of vegetation communities • Land clearing will be undertaken in Biodiversity Management Plan (Section 5) accordance with site Clearing Procedures Mine Rehabilitation and Closure Plan (Section to ensure clearing is minimised and is 5) conducted within defined boundaries Voluntary Offset Strategy (Section 4.1.8) • Ensure there is an appropriately qualified Environmental Officer on-site • Vegetation clearing / excavation to be subject to internal permitting system • Staging of the works to manage habitat loss • Demarcate exclusion zones to protect areas of vegetation to be retained prior to clearing • Measures to retain mature trees or habitat trees where possible • Collection of native seed from the Project area for use in rehabilitation program • Progressive rehabilitation of Project area; and • Ongoing implementation and monitoring of offsets. 2. Removal of threatened flora • Design of the new mine infrastructure Biodiversity Management Plan avoids clearing of threatened flora Mine Rehabilitation and Closure Plan species located in the Project area (S. Voluntary Offset Strategy rigens and E. cordatisepala) • Future works on Jervois Dam to consider nearby S. rigens and avoid impacts to the species • Speed restrictions on haul roads to lessen the impact of dust on specimens of E. cordatisepala located near roads
4.1-36 Jervois Base Metal Project
Environmental Impact Statement
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans • Ensure there is an appropriately qualified Environmental Officer on-site • Pre-clearing surveys to be undertaken within three months of clearing activities to ensure no harm to threatened flora species • Flag any areas of vegetation containing threatened flora species in or directly adjacent to the Project area as an exclusion area prior to works commencing • Collection of seed from mature individuals prior to clearing • Use of collected seed in revegetation. • Progressive rehabilitation of site • Monitoring program to monitor health of retained vegetation and rehabilitated areas • Ongoing implementation and monitoring of offsets • Employees and contractors will be required to participate in an environmental induction program. The program will provide information on employee environmental responsibilities as well as threatened flora 3. Introduction of exotic flora • Clearing of vegetation to be restricted to Biodiversity Management Plan the minimum required to enable the safe construction, operation and maintenance of the Project, including infrastructure corridors. • Weed surveys and implementation of control programs for weeds of significance
4.1-37 Jervois Base Metal Project
Impact Assessment
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans • Prioritisation of treatment of weed infestations or weed species and ongoing treatment regimes (as necessary) • Appropriate disposal of weed material to prevent further spread • Equipment hygiene program to minimise the risk of introduction or spread of weeds or soil borne diseases to the project area • Rehabilitation will be undertaken progressively; and • Employees and contractors will be required to participate in an environmental induction program. The program will provide information on employee environmental responsibilities as well as weed identification. 4. Dust • Stage clearing and construction activities Environmental Management Plan to minimise area of exposed ground • Establish and maintain a complaints management system for nearby landholders • Limit vehicle speeds on unsealed haul roads to reduce dust generation. • Visual inspection requirements • Progressive rehabilitation of the Project area. 5. Erosion and sedimentation • The surface water management system Erosion and Sediment Control Plan design incorporates the following Surface Water Management Plan components to control the discharge of run-off and sediment from the Project: o Raising of the existing Jervois Dam by approximately 1.5 m and buttressing of the downstream slope
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-38
Environmental Impact Statement
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans o Backfilling the existing Jervois Dam spillway o Construction of a new spillway to the south of the main Jervois Dam embankment o Construction of a diversion bund to the west of the proposed Marshall / Reward waste dump o Construction of a diversion channel to the east of the eastern perimeter of the TSF to divert water towards the catchment to the south o Construction of a bund between the eastern face of the Marshall / Reward waste dump and the western perimeter of the Marshall / Reward pit. o Construction of a diversion channel at the northern end of the Marshall / Reward pit; and o Construction of two sediment control dams • Monitoring of water quality in Unca Creek; and • Monitoring of sediment dams. 6. Hydrological change • The existing Jervois Dam will undergo Surface Water Management Plan repairs to minimise water losses and maximise water recovery • Follow hierarchy of water supply: o Use of mine water and non-potable raw water o Jervois dam; and o External groundwater borefield.
4.1-39 Jervois Base Metal Project
Impact Assessment
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans • Implementation of mine water management system (WRM Water & Environment P/L, 2018) • Monitor the use of water and implement water restrictions, where possible • Use of water is within the limits defined by any development approvals or conditions. • Ongoing monitoring of the health of the E. camaldulensis riparian vegetation community; and • Ongoing monitoring of borefield. 7. Contamination from hazardous Hazardous materials Surface Water Management Plan materials, waste rock and tailings • Hazardous materials will be stored in sign Waste Management Plan storage posted designated areas or in labelled Emergency Response Plan storage containers. These storage areas Mine Closure and Rehabilitation Plan will be bunded in accordance with AS 1940. Storage areas will also be located away from drainage lines and spill kits will be located in readily accessible locations. Storage facilities will be subject to regular inspections and housekeeping to ensure the integrity of the facilities are maintained • All listed waste will be removed and managed off site by appropriately licensed waste companies who are authorised to collect, transport, store, treat, recycle or dispose of specific listed wastes. Certificates of disposal will be kept on site • Emergency management procedures for hazardous materials will include those outlined in the site safety system Emergency Response Plan. Depending on
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-40
Environmental Impact Statement
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans the situation, emergency responses will include isolation, containment, evacuation, monitoring, remediation, investigation and process reviews to prevent recurrences Tailings storage • The TSF will be designed in accordance with the ANCOLD “Guidelines on Tailings Dams”, in particular regarding Extreme Storm Storage, Contingency Freeboard, Spillway Capacity, Design Earthquake Loading, Stability Minimum Factor of Safety, Dam Safety/Inspection Frequency • Maintenance of TSF in accordance with specifications • Ongoing water quality monitoring program to assess continued compliance with development approvals and conditions. Monitoring to be upstream and downstream of release points, as well as at release point • Spills or exceedance of water quality parameters are to be reported to the Environmental Officer, who will take appropriate action • Develop Emergency Overflow Procedures to deal with contamination events • Tailings will be paste backfilled into underground workings preferentially to reduce the inventory of tailings requiring surface management. Preferably on closure, tailings will be returned to the pit void. Detailed studies will be carried out in the detailed design stage to investigate
4.1-41 Jervois Base Metal Project
Impact Assessment
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans the feasibility of the preferred TSF rehabilitation option; and • An alternative option for TSF rehabilitation will be to install a basic store and release cover system to isolate the tailings from the environment. Waste rock • Waste rock will be retained within underground voids and pits where possible to minimise the operational footprint requiring rehabilitation. • The overburden and Waste Rock Landforms for each pit and underground mine will be rehabilitated. This will involve: o Shaping of dump slopes (batters) to shallow angles to control erosion, and appropriate drainage control measures. The exact slopes, top surface profile and drainage measures will be determined at the design stage taking into account waste characterisation, material availability and climatic conditions o Re-spreading of topsoil on shaped surfaces o Construction of low bunds at the crest of each batter to assist with surface water control on batters o Deep ripping on the contour to assist with water management and minimisation of erosion; and o Application of seed of local species.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-42
Environmental Impact Statement
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans 8. Bushfire • Provide fire breaks between the Project Bushfire Management Plan (BFMP) area and surrounding bushland and manage vegetation within buffer areas to maintain safe fuel loads • Implement the Hot work permits system, thus all welding, cutting and grinding to be undertaken on site to require a permit. Permits are to include detail control measures to be implemented, including: o Accessibility of firefighting equipment o Location of potential fuel sources o Work area establishment to identify ignition hazards; and o Current fire risk rating for the area. • All vehicles and work areas will be equipped with fire suppression and firefighting equipment • Ensure access tracks are able to be used for fire-fighting and other emergency purposes • Ensure all personnel, contractors and visitors are informed about BFMP and controls, through induction processes and meetings • A nominated person to be in charge for monitoring weather conditions and online resources for bushfire warnings; and • Implement a Safety Management System and associated frameworks to record and monitor fire including: o incident management framework, o hazard / near miss reporting process, o incident notification,
4.1-43 Jervois Base Metal Project
Impact Assessment
Potential Impact Mitigation measures Construction & Operation Relevant Management Plans o crisis management and evacuation framework.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-44
Operational management and monitoring plans The Jervois Mine will be required to have a Mining Management Plan (MMP) under the Mining Management Act 2001. The primary purpose of a Mining Management Plan (MMP) is to formalise the actions to be taken and strategies to be implemented, that combined, will manage impacts to the environment to acceptable and sustainable limits over both the short and long-term. The MMP has several components or sub-plans relating to the management of various issues. The Biodiversity Management Plan (BMP) has been developed to provide a clear and concise outline of the actions and methods required to mitigate likely impacts on biodiversity including: • Procedures to be adopted during vegetation clearing, including wildlife rescue procedures; • Weed and feral animal management; and • Mitigation of potential impacts on rare, threatened species.
In addition to this BMP, the management of biodiversity is addressed in several other sub-plans including: • Environmental Management Plan; • Erosion and Sediment Control Plan; • Water Management Plan; • Waste Management Plan; and • Bushfire Management Plan.
These sub-plans will consolidate information regarding the management of specific issues during the operation of the mine and provide for ongoing reference over the life of the mine. These management sub-plans will be kept on site for continual reference. The BMP forms part of the MMP for the Project and is considered to be a working document. It will be updated following formal assessment of the EIS by the NT EPA, and by Department of Primary Industry and Resources through the mine authorisation process. The BMP is provided as part of this EIS in Section 5.
4.1.7. Decommissioning of the mine At the end of the concept mine plan, it is expected that the mine site will be rehabilitated to be fit for the nominated future land use. Currently the Project area is part of the Jervois Pastoral Lease and has been used historically for mining and a low level of cattle grazing. It is anticipated that the post-mining land form will remain suitable for cattle grazing, with a combination of grassland and wooded areas representing the vegetation communities currently extant in the Project area.
Rehabilitation will be performed in accordance with contemporary accepted industry best practice and conducted in accordance with an approved MMP. KGL has prepared a Mine Rehabilitation and Closure Plan. The MRCP will be a dynamic document that is reviewed regularly to ensure the plan remains relevant to the activities being undertaken and planned to be undertaken. The MRCP will include a post-closure monitoring and reporting program to evaluate rehabilitation success and progress toward achieving closure objectives and contingency measures to be implemented in the event that monitoring demonstrates that rehabilitation closure objectives are not being met.
4.1.8. Voluntary offset strategy The ecological investigations on the Project area have determined that there is no significant impact to any Matters of National Environmental Significance (MNES) protected under the EPBC Act and therefore no requirements for the provision of offsets under the Commonwealth legislation.
There is no legislation governing the application of offsets in the Northern Territory, however, a Guideline on Environmental Offsets and Associated Approval Conditions (Northern Territory Environment Protection Authority (NT EPA), 2013) has been published to foster the coordination of
4-45 Jervois Base Metal Project
Impact Assessment offsets that may be imposed as a condition of approval under the Northern Territory’s Mining Management Act (MMA).
Significant values directly or indirectly impacted for biodiversity (but are not required to be offset under EPBC Act or NT legislation), include the Unca Creek riparian communities – removal of buffer vegetation.
Due to the nature of the Project, the impacts on the above listed values may be unavoidable; and whilst they are not significant on a national, state or bioregional scale, they may have a local impact on biodiversity in the Jervois Range. Table 4.1-7 describes some options that the proponent will investigate for a voluntary offset to help ameliorate local impacts to biodiversity.
Table 4.1-7 Potential offsets for impacts to biodiversity Impact Specific value Potential voluntary offset Removal of mature • Old growth trees. • Installation of nest boxes bloodwood and ironwood • Habitat trees (den and in other areas of similar stand (2.56 ha) for nest sites) for arboreal habitat. construction of tailings dam. mammals and parrots. • Set aside other areas of the same vegetation community within the lease for conservation in perpetuity, to manage until they reach a state where they may provide the same habitat values as the mature forest. Offset ratio of 3:1. Removal of vegetation in • Wildlife movement • Set aside other areas of waterway buffer areas as corridor and refuge the same vegetation specified in the Northern habitat for common community within the Territory Land Clearing fauna species, along lease for conservation in Guidelines (NT NREAS, 2010) Unca Creek. perpetuity, to manage • Bank stability. until they reach a state • Water quality. where they may provide the same habitat values as the mature forest. Offset ratio of 3:1.
Further work will be required to identify areas of potential offsets.
4.1.9. Conclusion The Jervois Base Metal Project Environmental Impact Statement (EIS) Terms of Reference has identified terrestrial flora and vegetation as a preliminary environmental factor that may be impacted by the Project. In order to better understand the terrestrial flora and vegetation values of the Project area, a number of ecological investigations were undertaken by Low Ecological Services P/L between 1985 and 2018. The studies included desktop assessment (i.e. interrogation of spatial databases and reviews of relevant literature) and field work involving on-ground vegetation surveys in 1999, 2012, 2013, 2017 and 2018. Survey methods for vegetation surveys and landscape description were based on “Northern Territory Guidelines and Field Methodology for Vegetation Survey and Mapping”
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-46
Environmental Impact Statement
(Brocklehurst, 2007) and “A resource assessment towards a conservation strategy for the Finke Bioregion” (Neave, 2004). Additional targeted surveys were conducted for flora species of conservation significance listed under the TPWC Act that were identified in database searches as potentially occurring within the Project area.
Based on survey results, eight refined vegetation communities have been mapped over the entire Project area (3,800 ha) that is located mostly within the Jervois Range Site of Botanical Significance (SoBS). The riparian vegetation community along Unca Creek was identified as having a potential interaction with shallow groundwater. Two flora species listed as near threatened under the Territory Parks and Wildlife Conservation Act (TPWC Act), Eremophila cordatisepala and Sauropus rigens, were recorded during on-ground surveys. There were no communities or flora species listed under the EPBC Act located in the Project area. The Project area contained two declared weed species Tamarix aphylla (athel pine) and Cylindropuntia fulgida var. mamillata (coral cactus), but was generally considered to be in good condition considering a long history (since 1929) of mining and the presence of some existing mining infrastructure.
The construction and operation of the mine is associated with a number of potential impacts to the floristic values of the Project area, including: • Vegetation clearing for pits and infrastructure • Impacts to threatened flora • Introduction of exotic flora • Dust pollution • Erosion and sedimentation • Changes in hydrology • Release of contaminants from tailings dams and waste rock; and • Bushfire.
A risk assessment process as described in AS/NZS 4360 (1999) and ISO 31000 (2009) has been undertaken for each impact before the application of any mitigation measures. Risk levels for impacts to floristic values of the Project area ranged from low to high. The application of mitigation measures will ameliorate the level of risk to an acceptable level for the Project.
The Jervois Mine will be required to have a Mining Management Plan (MMP) under the Mining Management Act 2001. The primary purpose of a Mining Management Plan (MMP) is to formalise the actions to be taken and strategies to be implemented, that combined, will manage impacts to the environment to acceptable and sustainable limits over both the short and long-term. The MMP has several components or sub-plans relating to the management of various issues. The Biodiversity Management Plan (BMP) has been developed to provide a clear and concise outline of the actions and methods required to mitigate likely impacts on biodiversity including: • Procedures to be adopted during vegetation clearing, including wildlife rescue procedures; • Weed and feral animal management; and • Mitigation of potential impacts on rare, threatened species.
Other sub-plans will also have components addressing biodiversity, such as the Environmental Management Plan, Erosion and Sediment Control Plan, Water Management Plan, Waste Management Plan, Bushfire Management Plan and Mine Rehabilitation and Closure Plan. The BMP forms part of the MMP for the Project and is considered to be a working document. It will be updated following formal assessment of the EIS by the NT EPA, and by Department of Primary Industry and Resources through the mine authorisation process. Further, a voluntary offset strategy has been proposed for
4.1-47 Jervois Base Metal Project
Impact Assessment the removal of some ecological values considered to be of local significance in the ecological assessments completed for the Project.
SECTION 4.1 | Terrestrial Flora and Vegetation 4.1-48