part of this Proposal). Clearing and grubbing will occur progressively, approximately one month
prior to these investigations.
Clear and Grubbing
Q3 2011 – Q4 2012
Areas of environmental or cultural significantce will be demarcated. Graders, bulldozers and
scrapers will be used to clear the Rail Corridor prior to construction. Vegetation and topsoil
cleared and stockpiled for rehabilitation purposes. This will occur continuously along the rail line.
Temporary Facilities
Q2 2011 to Q3 2012
Temporary facilities such as construction camps, workshops, sleeper factory and laydown areas
will be established to support construction of the rail.
Bulk Earthworks and
Rail Formation
Construction (including
culverts and bridges)
Q4 2011 – Q2 2013
Following clearing and grubbing, earthmoving equipment (e.g. graders, scrapers, loaders,
rollers and water carts etc) will be mobilised for construction of the rail embankment and
formation, culverts and bridges. Construction material will be sourced from quarries and borrow
areas and placed in a manner to withstand the eventual weight of rail operations.
Blasting
Q2 2011 – Q3 2012
Blasting will be required in traversing areas of rock and in the construction of cuttings. This will
occur progressively along the rail formation.
Borrow Pits and
Quarries
Q3 2011 – Q2 2013
A number of borrow pits and at least three quarries are required to provide material for Proposal
construction.
Bridge construction
Q4 2011 – Q1 2013
Nine bridges will be constructed along the rail. Independent bridge construction crews will be
engaged for this work.
Sleeper and Track
Laying
Q2 2012 – Q3 2013
Sleeper and track laying will occur progressively from the 34 km point of the Proposal. Pre-
welded track in lengths of approximately 440 m will be transported by train via the progressively
extended track. Rehabilitation will occur progressively in conjunction with track laying.
Signs, communication
and signals (including
cable laying)
Q1 2012 – Q4 2013
Signals and communications will be incorporated into the track during and after construction and
will include signal lights at level crossings and switch pads.
Commissioning
Q2 2013 to Q1 2014
Commissioning will comprise the trial running of light high-rail vehicles, followed by a series of
incrementally loaded trains until fully loaded trains are run and the rail track is opened for full
operation.
Demobilisation and
Final Rehabilitation
Q1 2014
Rehabilitation of all excess disturbed areas will have been commenced within 12 months of
construction completion.
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5
EXISTING ENVIRONMENT
5.1
REGIONAL SETTING
As the Proposal Area extends some 570 km north east from Oakajee to Jack Hills, environmental
conditions within the Rail Corridor vary considerably. The main factors contributing to this change
are distance from the coast, drainage patterns, geology and soils. In the following sections,
descriptions generally relate to ‘coastal’ or ‘inland’ to cover the range of conditions.
5.1.1
Climate
Bureau of Meteorology (BoM) data indicates that the Mid‐West region experiences a Mediterranean
type climate, with hot dry summers and mild wet winters near the coast, becoming progressively
drier and warmer inland (BoM, 2009). Climatic data from Geraldton and Meekatharra
meteorological stations represents the climatic extremes for the Proposal Area (Figure 5‐1 and Figure
5‐2)
5.1.1.1
Rainfall
Data from the BoM indicates that Geraldton’s rainfall averages 460 mm per annum, peaking during
the winter months (Figure 5‐1). Being further inland, Meekatharra’s rainfall is more variable over the
year but generally averages 237 mm (Figure 5‐2).
5.1.1.2
Temperature
Maximum temperatures in summer average between 30°C near the coast and 38°C inland with the
hottest months being January and February, while in winter maximums average 19°C across the
Proposal Area during June and July (BoM, 2009).
Figure 5‐1 Mean annual rainfall and temperature for Geraldton (BoM 2009)
0
5
10
15
20
25
30
35
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
T
em
p
er
atu
re (C
)
0
20
40
60
80
100
120
140
R
ain
fa
ll (
mm)
Rainfall
Temperature
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Figure 5‐2 Mean annual rainfall and temperature for Meekatharra (BoM 2009)
5.1.1.3
Wind
Geraldton’s wind climate is dominated by the effects of the land‐sea interface where offshore land
breezes are common in the morning, whilst afternoon sea breezes are common in the warmer
months. Meekatharra also experiences land breezes from the interior, with a tendency to be drying
and hot in the summer and without the relief of the coastal sea breeze (BoM, 2009). Wind roses for
Geraldton and Meekatharra are presented in Figure 5‐3 and Figure 5‐4 respectively.
0
5
10
15
20
25
30
35
40
45
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
T
em
p
erat
u
re
(
C
)
0
5
10
15
20
25
30
35
40
R
ai
n
fa
ll
(
m
m
)
Rainfall
Temperature
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Figure 5‐3 9am and 3pm wind roses from Geraldton weather station
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Figure 5‐4 9am and 3pm wind roses from Meekatharra weather station
5.1.2
Biogeography
The Interim Biogeographic Regionalisation for Australia (IBRA) classifies the continent into regions
(bioregions) of similar geology, landform, vegetation, fauna and climate (Department of
Environment, Water, Heritage and the Arts, 2009). According to IBRA (Version 6.1) the Proposal Area
intersects the Geraldton Sandplains (GS2), the Yalgoo (YAL2) and the Murchison bioregions. Each of
the IBRA regions is further divided into sub‐regions as described below and mapped on Figure 5‐5.
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5.1.2.1
Geraldton Sandplains
Near the coast, the Proposal traverses the Geraldton Hills sub‐region of the GS2 Bioregion. The sub‐
region comprises mainly proteaceous scrub‐heaths, rich in endemics, with the small regional reserves
along the coast and inland. Extensive York Gum and Jam woodlands occur on outwash plains, and
heaths with emergent Banksia, Actinostrobus and York Gum woodlands on alluvial plains. Dominant
land uses are dry land agriculture (65.8% by area), conservation (13.8% by area) and rural residential
(DEC, 2002). This subregion has approximately 16% of its pre‐European vegetation remaining
(Shephard 2002).
5.1.2.2
Tallering
The Proposal traverses the central YAL2 sub‐region where the grazing of native pastures is the
predominant land use (approximately 77% by area). The sub‐region is characterised by low woodland
or tall shrublands of mulga (Acacia aneura) on red loams. The undulating sandplains support
scattered mulga and mallee (Eucalyptus kingsmills) over hummock grasslands. Mixed communities
of low open woodlands of mulga and bowgada with heath and spinifex are characteristic of the
sandplains (Payne, et. al., 1998). The YAL2 sub‐region has 719 recorded plant species, 27 of which
are listed as Declared Rare Flora or Priority species. This subregion has approximately 98.9% of its
pre‐European vegetation remaining (Shephard 2002).
5.1.2.3
Western Murchison
The easternmost portion of the Proposal, including the Jack Hills Loop and the Weld Range Link,
extends into the Western Murchison sub‐region. The vegetation of the sub‐region comprises low
mulga woodlands, often rich in ephemerals (usually with bunch grasses), with saltbush shrublands
occurring on calcareous soils. Hummock grasslands are common on the Sandplains (DEC, 2002).
Pastoralism is the dominant land use (96% coverage by area) and although Shephard (2002) indicates
that effectively all of the sub‐region retains native vegetation, degradation is widespread as a result
of grazing by pastoral stock and other introduced herbivores. This subregion has approximately 100%
of its pre‐European vegetation remaining (Shephard 2002).
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Figure 5‐5 IBRA Regions associated with the Proposal
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5.1.3
Land Systems
Rogers (1996) conducted an inventory of soil and land resources of the Geraldton
Agricultural Region. 51 soil‐landscape systems were described, based on geology, landform
and soil characteristics. The Proposal Area incorporates eleven of Rogers’ soil‐landscape
systems. Table 5‐1 identifies these systems and the proportion of their total extent that
occurs within the Study Area.
Table 5‐1 Soil landscape systems occuring within the Proposal Area
Soil Landscape system
Total Area (ha)
Area in Proposal Area
(ha)
Percent of Total System (%)
Binnu 138843
8947
6.44
Casuarina 70117
430 0.61
Dartmoor 115013
15678
13.63
Eradu 145118
7183
4.95
Greenough 17976
4620 25.70
Moresby 26697
2144
8.03
Mt Horner
29451
395
1.34
Northampton 83511
5348 6.40
Quindalup 3077
564
18.32
Sugarloaf 57582
2021
3.51
Tamala 13572
2156
15.89
A comprehensive inventory of the land systems of the Murchison region has been developed
based on biophysical characteristics such as geology, landforms, vegetation and soils. The
methodology was initially applied by Curry et al (1994) in the Murchison River Catchment
and surrounds, and then by Payne et al. (1998) in the Sandstone‐Yalgoo‐Paynes Find area.
Each land system is classified into a particular land type defined by the landforms and
vegetation it contains. As the technique has been applied only within the Murchison region,
the portion of the Rail Corridor beyond this region is described using soil landscape systems,
as described above.
The Study Area encompasses 30 land systems, all of which are considered to be well
represented beyond the Study Area. All land systems within the Study Area and the
proportion of each land system being affected are shown in Table 5‐2.
The most common land systems within the Proposal Area, each comprising over 10% of the
entire area, are the Challenge, Tindalarra and Yanganoo systems. At approximately 10%
each of their overall extent, the Weld and Yarrameedie land systems are proportionally the
most represented within the Study Area.
5.1.1
Topography
The Mid‐West Region can broadly be divided into a coastal plain, a coastal plateau, and an
interior plateau, and the Proposal Area spans all three. The coastal plain is approximately 20
kilometres wide and is characterised by undulating sand‐dunes. The coastal plateau ranges
from approximately 50 m to 300 m above sea level, and is a fairly flat sandplain, with some
ridges and mesas. The interior plateau is generally of lower relief, and is more variable, with
paleodrainage valleys between escarpments.
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Table 5‐2 Land systems occurring within the Study Area
Land System
Total Area (ha)
Area in Proposal Area
(ha)
Percent of total Land
System (%)
Belele 578,300
4,352
0.7
Beringarra 262,436
1,422 0.5
Challenge 1,010,000
17,211 1.7
Cunyu 329,933
1,545
0.5
Ero 215,007
3,907
1.8
Flood 159,252
2,999
1.9
Gabanintha 251,455
2,688 1.1
Joseph 464,045
809
0.2
Jundee 660,224
4,363
0.7
Kalli 1,115,901
16,124
1.4
Koonmarra 569,874
11,997 2.1
Mileura 261,223
1,454
0.6
Millex 47,825
2,867
6.0
Millrose
109,649 1,317
1.2
Mindura 440,593
3,156
0.7
Mulline 19,688
89
0.4
Nerramyne
250,958 5,752
2.3
Norie
211,177 2,393
1.1
Pindar
151,876 646
0.4
Sherwood 1,579,691
9,636 0.6
Tallering 32,949
1,045
3.2
Tindalarra 713,173
29,231 4.1
Violet 584,096
1,981
0.3
Waguin
317,146 586
0.2
Weld 37,235
3,604
9.7
Wiluna 258,978
814
0.3
Yandil 494,525
3,055
0.6
Yanganoo 2,019,907
35,446 1.7
Yarrameedie 68,324 7,045 10.3
Yewin 45,709
1,692
3.7
5.1.2
Geology
The Proposal Area traverses two major geomorphologic units, the northern Perth Basin and
the Yilgarn Craton which are separated by the Darling Fault. The Perth Basin is a north to
north‐northwest trending, onshore and offshore sedimentary basin extending about 1,300
km along the south‐western margin of the Australian continent (Geoscience Australia, 2008).
The Yilgarn Craton is the oldest and largest craton in Australia and comprises a gently
undulating landscape characterised by rock of Archaean origin, chiefly granite with north to
northwest belts of greenstone rock formation.
The greenstone formations comprise ranges of hills widely separated by flat plains derived
from colluvium and alluvium. Prevailing topography is a result of extensive weathering of
the underlying geological provinces (Anand and Paine, 2002). Weld Range and Jack Hills are
two of the greenstone belt ridges representing the northern extent of the Yilgarn Craton and
these feature comprise mainly haematite, magnetite and silica Banded Iron Formation (BIF)
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rock. BIF is relatively erosion resistant and thus has resulted in the rocky outcrops and steep
ridges characteristic of the area (Anand and Paine, 2002).
Most of the Mid‐West region lies within the Murchison Province, which is the most western
of the three granite‐greenstone terrains in the Archaean Yilgarn Craton. In the north and
northwest, the Murchison Province is in tectonic contact with the Narryer Gneiss of the
Western Gneiss Terrain, whilst to the northeast the granite‐greenstone rocks are overlain by
Proterozoic sediments of the Nabberu Basin. Overlying the basement rocks, in particular
along the palaeodrainages, are alluvial, colluvial and valley calcrete deposits of Cainozoic age
(Johnson and Commander, 2006).
The geology is characterised by northwest to northeast trending granite‐greenstone belts
that display low to medium‐grade metamorphism, which have been intruded by east‐west
dolerite dykes of Proterozoic age. The greenstones are comprised of metamorphic, igneous
and sedimentary rocks that have been highly sheared and fractured. The granites tend to be
relatively massive, except for local shearing along margins or joints. These basement rocks
are poorly exposed in the Study Area due to the low relief, widespread superficial cover, and
extensive deep weathering (Aquaterra, 2009b).
Sedimentary rocks of the Northern Perth Basin underlie the western portion of the Mid‐
West region. The inland extent of these sediments is marked by the Darling Fault. In the
west, sediments of both the Perth and Carnarvon Basins flank the granitic Northampton
Block (Johnson and Commander, 2006).
The Northampton Block is a relatively small area of Proterozoic crystalline basement that
occurs in the west. The metamorphosed granulite, granite and migmite rocks form part of a
linear ridge that separates the Perth and Carnarvon Basins.
The sediments of the North Perth Basin occur to the west of the Darling Fault and Yilgarn
Craton. The Phanerozoic sediments, including the Yarragadee Formation, Parmelia
Formation and Tumblagooda Sandstone, are deposited as a series of interbedded sandstone,
siltstone, claystone and shale (Johnson and Commander, 2006).
The Permian sediments of the Carnarvon Basin consist of a series of sandstone,
conglomerate, siltstone, claystone, carbonaceous shale and some tillites. At the coast and in
the southern part of the Carnarvon Basin, there are prominent outcrops of the Silurian
Tumblagooda Sandstone (Johnson and Commander, 2006).
Further details of the regional geology of the Mid‐West region are presented in Appendix 4
(Aquaterra, 2009b). Hydrogeology is discussed in Section 5.2.4.1
5.1.3
Soils
The dominant soil types in the Mid‐West are shallow loams with a red‐brown hardpan.
These are associated with yellow earth in the Murchison areas, and rocky stony soils. Soils
overlay red‐brown hardpan to 1.5 m depth, others overlay remnants of lateritic profiles and
frequently have limestone gravel. Soils on hard rock are stony.
5.1.3.1
Acid Sulfate Soils
To assist in clarifying the potential for acid sulfate soils (ASS) occurrence along the rail
alignment, Oakajee Port and Rail (OPR) commissioned a desk‐based investigation of ASS risk
along a potential alignment (GHD, 2010). A low to moderate ASS risk was determined for
the majority of Study Area, with moderate to high risk areas (predominantly associated with
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alluvium, and isolated salt pans) also identified at several locations. The full results
(including detailed maps) can be found in Appendix 5, and are summarised as follows:
41.9% of areas no to low risk: Areas with this classification comprise strata that are
not known to normally pose significant ASS risks. Examples from the site include
igneous rocks (granite, gabbro), meta‐sedimentary rocks (migmatite, schist), and
sedimentary rocks (sandstone);
42.0% of areas low to moderate risk: Areas with this classification are comprised
mostly of low risk strata, along with limited areas of strata that are known to pose
potential ASS risks (for example alluvium/salt pan deposits). Examples from the site
include areas of exposed basement rocks (e.g. granite) interspersed with colluvium,
or minor quantities of alluvium; and
16.1% of areas moderate to high risk: Areas with this classification comprise
significant quantities of strata that are known to pose significant potential ASS
risks. Examples from the site include large areas of superficial deposits such as
colluvium that contain extensive areas of alluvium materials and/or salt pan
deposits.
With consideration of the anticipated excavation depths along the alignment (based on
preliminary cut and fill data provided by OPR dated 12 January 2010), the risks were revised
as follows:
91.2% no to low risk;
7.5% low to moderate risk; and
1.3% moderate to high risk.
5.1.4
Conservation Estates / Significant Areas
Of the IBRA subregions crossed by the Proposal Area, 0.01 ‐ 5% of the Tallering and Western
Murchison subregions are protected under the national reserve system, while the Geraldton
Hills subregion has a much higher percent of 15 ‐ 30% protected (DEWHA, 2008).
The Department of Environment and Conservation (DEC) announced new conservation lands
in the Gascoyne, Murchison and south west regions in September 2007. These included the
pastoral land area (whole or part) of the ‘Gascoyne‐Murchison Strategy’ and the freehold
land area in the south west. Most of the acquired pastoral leases and a few of the freehold
areas are proposed to be reserved as unclassified conservation parks under the Conservation
and Land Management Act 1984.
The Proposal Area crosses four current or proposed conservation reserves listed in Table 5‐3
(Figure 5‐6). Four others have been recently excised from the Proposal Area (are no longer
part of the Proposal Area).
The Proposal Area does intersect the Moresby Range Strategy Area, approximately six km
from the coast, but the Moresby Range Strategy (WAPC 2009) makes an allowance for an
infrastructure corridor through this area.
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