HVO 2009 Annual Environmental Management Report - Final

Coal & Allied – Hunter Valley Operations
Water Outputs
The main consumption of water in 2009 was for dust suppression on haul roads, mining areas and coal
stockpiles (1,533ML) and CPP circuit losses (2,912ML). Evaporation from water storages and tailings dams
was estimated at 2,034ML in 2009.
A total of 192ML of excess water was discharged off site during 2009 in accordance with the Hunter River
Salinity Trading Scheme (HRSTS) and HVO’s EPL. Refer to Section 3.4.2 for further details.
Water Storage and Transfer
At the end of 2009 the overall volume of water stored at HVO had increased by 3,297ML. The primary storage
for mine water is the North Pit Void. Storage in the North Pit Void increased by an estimated 989ML during
2009. Use of water from the North Pit Void was limited in 2009 due to preferential use of water stored in pit.
Water levels in the South Pit increased markedly over the year, accounting for about half the overall storage
increase. Water levels in Riverview East Void (3,280ML) increased by 860ML. Riverview East Void was the
primary dewatering destination from Cheshunt and Riverview mining pits in 2009. Water from Riverview East
Void was transferred back to the Hunter Valley CHPP via Dam 9N, and to the new storage in the Barry Pit
Void which increased to 180ML. The Riverview East Void storage will be replaced by the Barry Pit storage in
2010 as the Cheshunt Pit moves south west. Water stored in the North and South Auger Pits, South
Lemington and several other small South Pit voids increased by 650ML.
Parnells Dam is the main water storage for West Pit. Water stored in Parnells Dam and West Pit increased by
330ML over the reporting period.
2.8.2 Improvements to Mine Water Management
Improvements to mine water management in 2009 have focussed on improving mine water transfer,
segregating clean and mining catchments and improvements to discharge points. This included:
Implementation of clean water diversions for Carrington Pit and Riverview East Void;
Constructing replacement storage for Riverview East Void in Barrys Pit; and
Upgrade of discharge monitoring instrumentation at Parnells Dam and Dam 11N to improve operability
and reduce risk of discharge non-compliance.
2.8.3 Mine Water Management System
The water management system is designed to contain all mine water arising from runoff within disturbed
areas. Plans showing the layout of all water management structures and key pipelines are shown in Figure 11
to Figure 13.
West Pit
West Pit mine water management structures (Figure 11) are based around Parnells Dam and the Emu Creek
Dam (Dam 12W). Howick CPP, Industrial Area and Dams 2W to 6W contain process water.
North Pit/Carrington
North Pit mine water management structures (Figure 12) are Dams 9N, 11N, the South East Sump (21N) and
the North Pit Tailings Dam (30N). Excess mine water from Carrington Pit is pumped into Dam 9N or to the
South East Sump where it can be directed to the HVCPP, discharged or used for dust suppression. Water is
recovered from the North Pit Tailings Dam via a surface pump. This water is pumped to Dam 9N or the South
East Sump for use in the HVCPP or dust suppression. At the HVCPP and main Workshop, Dams 16N to 19N
contain process water (a mixture of various water qualities) while Dam 15N is operated empty as an
emergency storm buffer storage for overflows from Dam 16N and 19N.
South Pit
The Riverview East Void (Dam 20S) operates as a central mine water storage for the mining areas south of
the Hunter River (Figure 13) receiving excess mine water from Cheshunt and Riverview Pits. This will be
replaced by Barrys Void water storage in 2010 due to mining through Dam 20S. Water from Dam 20S is used
for dust suppression or pumped to Dam 9N via the north south pipeline to supply the HVCPP. Water from
Cheshunt and Riverview can also be pumped east to the Lake James (Dam 15S) discharge point. The East
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