Wambo Coal AEMR 2011-2012 - Peabody Energy

27 July 2012
Wambo Coal Pty Ltd
GPO Box 5101
Brisbane QLD 4001
Attention:
David Rankins
Subject:
2012 AEMR Noise Summary
Dear David,
Please find below a summary of the continuous noise monitoring assessment for Wambo Coal Mine
(WCM) for the period 1 July, 2011, to 30 June, 2012.
July to September, 2011
Assessment of noise impacts for the July to September, 2011, monitoring period indicates that WCM
complied with the noise level criteria prescribed in the Wambo Coal NMP. Review of the L A1,1minute
results indicates that animal noise, road noise and meteorological influences dominate the LA1 noise
environment adjacent to the WCM. Mining noise was encountered during audio review at the N21
(WA) and N16 (Muller) site locations. However, this was considered to represent only the background
contribution to measured noise levels rather than the transient or peak events associated with potential
for sleep disturbance. It should be noted that the N16 (Muller) monitoring location is subject to
cumulative mining noise impacts, and as the source of mine noise contributions could not be
confirmed, exceedences could not be attributed to the WCM.
Where mining noise impacts were observed, uncertainty exists in the validity of the monitoring data.
While EPL 529 excludes data influenced by strong temperature inversions (lapse rates of 3 C/100m
and wind speeds up to 2 m/s), the methods available to assess atmospheric stability (sigma-theta
method) provide conflicting evaluation as to the validity of the noise monitoring data. Pasquill Gifford
(P-G) ‘F’ class stability was commonly observed during the monitoring period, denoting temperature
lapse rates of between +1.5 and +4.0 deg/C per 100m. It stands to reason that portions of the dataset
monitored under ‘F’ class stability conditions would be subject to lapse rates in excess of 3.0 deg/C per
100m; however, in the absence of available methods or data, the frequency of this scenario could not
be determined. Consequently, all noise monitoring results observed under ‘F’ class conditions were
retained in the analysis.
October to December, 2011
Assessment of continuous noise monitoring data indicated that the WCM complied with the
L AeqLF,15minute noise level criteria for more than 88% of time at the N21 (WA) monitoring location and
98% of the time at the N20 (Thelander) monitoring location. Following a conservative detailed analysis
of the N16 (Muller) monitoring data, it was found that L AeqLF,15minute noise levels attributable to WCM
operations exceeded the 40dB(A) criteria approximately 22% of the monitoring period. The measured
exceedence rate attributable to all environmental noise sources at this location was approximately
48%.