HVO 2009 Annual Environmental Management Report - Final

Coal & Allied – Hunter Valley Operations
8.5
Cheshunt Stage 1 Groundwater pH Trends
8
7.5
pH(pH units)
7
6.5
6
Jan 09
Feb 09
Mar 09
Apr 09
May 09
Jun 09
Jul 09 Aug 09
Date
Sep 09
Oct 09
Nov 09
Dec 09
Jan 10
BC1A BZ1-1 BZ1-2 BZ1-3 BZ3-1 BZ3-2 BZ3-3 BZ4A(1) BZ4A(2)
BZ8-2 HG1 HG2 HG2A HG3
Figure 57: Cheshunt Stage 1 Groundwater pH Trends
Groundwater Monitoring EC Results for Cheshunt Stage One Piezometers
The highest average EC reading of 14,120μS/cm was recorded at BZ4A(1) with the lowest average EC
reading of 920μS/cm. Other EC levels remained stable (Figure 58).
The EC levels at BZ1-1 (sandstone/interburden) trended upwards in 2008 from 4,710μS/cm at the end of
2007, and then levelled off at an average level of 8,232μS/cm in 2008. In 2009 the EC dropped significantly
from 9,000μS/cm to 2,800μS/cm in June and September, before returning to a maximum of 11,300μS/cm.
The cause of this variation remains unknown and the site will continue to be monitored in 2010.
The EC levels for BZ3-2 indicate a substantial increasing trend from 500μS/cm in June 2007 to 5,520μS/cm in
December 2008. Following a small return to 2460μS/cm in March 2009, an increasing trend, peaking at
6780μS/cm, was observed at the end of the 2009 reporting period.
15,000
Cheshunt Stage 1 Groundwater EC Trends
14,000
13,000
12,000
11,000
Electrical Conductivity (uS/cm)
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0
Jan 09
Feb 09 Mar 09
Apr 09
May 09
Jun 09
Jul 09 Aug 09
Date
Sep 09
Oct 09
Nov 09
Dec 09
Jan 10
BC1A BZ1-1 BZ1-2 BZ1-3 BZ3-1 BZ3-2 BZ3-3 BZ4A(1) BZ4A(2)
BZ8-2 HG1 HG2 HG2A HG3
Figure 58: Cheshunt Stage 1 Groundwater EC Trends
AEMR 2009 110