Wambo Coal AEMR 2011-2012 - Peabody Energy

2011-2012 AEMR
5.1.3 NWC Diversion
Following Stage 2 completion of the NWC Diversion
construction works, all disturbed areas were
rehabilitated in 2008/2009. Rehabilitation consisted
generally of topsoil application, application of soil
ameliorants, ripping, seeding (mainly a pasture
seedmix), and strategic tubestock planting to
provide long-term bank stabilisation. Revegetation
using hydromulching was also undertaken on
steeper batters.
Following the first two flows, or discharges, through
Stage 2 of the NWC Diversion in February and April
2009, an assessment of diversion condition and
bank stability was undertaken. The diversion was
inspected by the hydrological consultants who
designed the diversion (Gilbert and Associates) and
a Hunter Valley based consultancy that specialises
in rehabilitation and erosion control (GSS
Environmental). The two inspection reports (GSSE,
October 2009, and Gilbert & Associates, September
2009) identified several areas requiring remedial
attention.
During the reporting period, WCPL prepared
tenders for the remedial rehabilitation works within
Stage 2 NWC Diversion, based on the
recommendations provided from both GSSE and
Gilbert’s. After completing the Tendering process
and awarding contracts, rehabilitation works within
Stage 2 of the NWC Diversion commenced in April
2011, with works completed during June 2011.
North Wambo Creek Diversion (Stage 3)
Construction works were nearing completion on the
final stage (i.e. Stage 3) of the North Wambo Creek
Diversion program. At the end of the reporting
period approximately 800,000 m 3 of excavation had
been carried out to construct the permanent creek
line around the old Wollemi Underground Portal
area, in conjunction with revegetation works. The
construction of this diversion will allow the open cut
to progress mining the Bates South area and
provide future access to the proposed South Bates
underground longwall panels.
Stage 3 revegetation works for the flood bunding
and diversion channels and associated areas is
planned for early September 2012.
For full details regarding the North Wambo Creek
Diversion Discharge Report please refer to Section
2.8.2.2.
5.2 Rehabilitation Trials and
Research
During the previous reporting period, WCPL
commenced incorporating biosoilds into the Open
Cut rehabilitation program. A wider application area
was planned for the current reporting period, as well
as trial application of organic compost material. As
no rehabilitation was completed during this reporting
period, application of biosoilds and organic compost
is expected to occur during the next reporting
period.
The use of mobile tree mulching plant was utilised
throughout the reporting period and will be utilised
where possible during the next reporting period.
After identification and separate recovery of timber
and habitat trees, the mulcher will mulch trees in
situ, leaving a blanket of mulch, which assists with
dust suppression and erosion control, as well as
providing a source of organic matter in the stripped
topsoil.
5.3 Rehabilitation Monitoring
During the reporting period a program of works
associated with the monitoring of revegetated
disturbed riparian lands utilising the CSIRO
developed Ecosystem Function Analysis (EFA)
monitoring tool was undertaken. A separate survey
and report has been prepared for the monitoring of
rehabilitated areas associated with the Open Cut
areas.
The data that has been derived from the monitoring
program provides a scientifically robust platform
against which the effectiveness of rehabilitation
techniques can be assessed and where applicable
amended, with a view to achieving sustainable
vegetation communities on disturbed landscapes.
The purpose of the assessment is to determine
whether rehabilitated areas are on a trajectory
toward self sustainability and functionality.
The riparian areas surveyed included South Wambo
Creek and North Wambo Creek downstream of the
Open Cut offices. The second component of the
riparian monitoring program commenced in 2008
and focused on the North Wambo Creek Diversion
rehabilitation works.
5.3.1.1 Ecosystem Function Analysis
Summary
Open Cut EFA
RPS was engaged by Wambo Coal Pty Ltd (Wambo
Coal) to undertake the October 2011 Ecosystem
Function Analysis (EFA) monitoring of 14 previously
established open cut EFA transects. Twelve EFA
transects were established in 2006 comprising:
Six pasture rehabilitation transects;
Four woodland rehabilitation transects;
One pasture analogue transect; and
One woodland analogue transect.
A further two pasture rehabilitation transects were
created in 2008. During 2009 two pasture
rehabilitation transects were repositioned to more
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