Frequently Asked Questions

Mount Thorley Warkworth

How is handheld noise monitoring undertaken?

We have three Community Response Officers (CRO's) who complete routine attended noise monitoring, supported by the real time monitoring network. 

The CRO's carry out noise measurements at several locations around MTW each night. Assessments are completed as follows:

  • Calibration of the noise meter at the commencement of shift using a certified calibration device;
  • Monitoring is undertaken at the same position at each monitoring location;
  • A LAeq 5min measurement is collected;
  • The monitor is set to "Fast" response;
  • A Frequency filter is used, removing all noise sources which are present >850Hz;
  • The monitor is paused to avoid contamination with extraneous noise sources such as road traffic;
  • Once complete, the Community Response Officer apportions an estimation of the Total LAeq to the key noise source directions (Warkworth and Mount Thorley Mines); and
  • These estimated apportionments of the Total LAeq are recorded as the measured levels, and compared against the noise limits for the monitoring location

The CRO talks with the shift coordinator to make changes to the operations if noise levels exceed the noise criteria. As described in the MTW Noise Management Plan, any elevated noise measurements are corrected within 75 minutes of detection. To ensure this is achieved, the CRO will undertake several validation measurements after changes to operating conditions have been made, providing regular feedback to the Shift Coordinator.   

What are Mount Thorley Warkworth’s consent noise levels?

Specific noise limits apply to individual private residences, and can be found in the Mount Thorley Operations and Warkworth Mining Limited Development Consent documents. These range from 35 to 48dB LAeq (15min) during the day, evening and night; and 35 to 48dB  LA1 (1 minute) during the night.

The interactive map on this website displays the results of hand held noise monitoring at a range of representative monitoring locations. Noise limits which are applied to each location are aligned with the lowest consented noise limit for all residences which are represented by the monitoring location. In this way, MTW is able to ensure that compliance is maintained with the relevant noise limit for all nearby private residences. Noise monitoring locations are reviewed periodically and are subject to change. Noise monitoring is routinely undertaken at the following locations:

  • Wambo Road;
  • Inlet Road West;
  • Inlet Road;
  • Bulga Village;
  • Bulga Rural Fire Service Headquarters;
  • South Bulga; and
  • Long Point

How do you monitor air quality?

Monitoring is undertaken in accordance with the NSW Environmental Protection Authority’s (EPA) ‘Approved Methods for the Sampling and Analysis of Air Pollutants in New South Wales’ guidelines, which can be downloaded from the EPA’s website at http://www.epa.nsw.gov.au/air/index.htm.

MTW operates and maintains a network of air quality monitors, comprising both static monitors (Depositional Dust Gauges and High Volume Air Samplers), and real-time monitoring units. The air quality graphs presented on this website are displaying monitoring data collected through the real-time monitors. 

For information regarding monitoring locations, compliance assessment and reporting, and air quality management practices, please see the MTW Air Quality Management Plan.

My personal noise monitor reading tells me something different to what’s been published on the website, why?

Attended noise monitoring via a handheld monitor is a complex process. Our Community Response Officers have been trained in this monitoring technique by recognised acoustic specialists.  

The Community Response Officers complete their assessments as follows:

  • Calibration of the noise meter at the commencement of shift using a certified calibration device;
  • Monitoring is undertaken at the same position at each monitoring location;
  • A LAeq 5min measurement is collected;
  • The monitor is set to "Fast" response;
  • A Frequency filter is used, removing all noise sources which are present >850Hz;
  • The monitor is paused to avoid contamination with extraneous noise sources such as road traffic;
  • Once complete, the Community Response Officer apportions an estimation of the Total LAeq to the key noise source directions (Warkworth and Mount Thorley Mines); and
  • These estimated apportionments of the Total LAeq are recorded as the measured levels, and compared against the noise limits for the monitoring location

It should be noted that attended noise monitoring is a sampling exercise. Noise levels measured are representative of conditions at the time of assessment. Changes in meteorology and equipment operating locations / conditions can result in considerable differences in noise levels received.

We recognise that a number of interested community members regularly complete their own noise assessments to ensure MTW remains accountable for noise levels received at nearby private residences. While specific techniques employed by each resident are not known, there are a number of variables which could account for differences in measured levels, including:

  • Noise readings undertaken at different times, or for different measurement durations;
  • Differences in monitor setup, including use of frequency filtering and "pausing" techniques;
  • Knowledge of the geographical area, particularly the direction of individual mines; and
  • Natural bias from person to person in apportioning estimations of the total LAeq to individual mines

For more information on noise monitoring techniques, please see the MTW Noise Management Plan

Am I viewing the raw or validated noise data on this website?

The information on this website has been validated by our Environmental Services team to ensure there are no anomolies in the data, and that monitors have recorded accurately. Where gaps appear in the air quality trends or meteorological data, it is indicative of a monitor outage or communications fault. 

Am I able to receive soundproofing or dust reduction mitigation works for my home?

Property mitigation works such as soundproofing are governed by a Voluntary Land Acquisition and Mitigation Policy and apply to development applications and modifications in the provisions of the Environmental Planning and Assessment Act 1979.

Under a mine's development consent, some properties may be prescribed mitigation rights based on  noise and air quality assessments. 

Mitigation rights reflect the type of impact a landholder may experience. Mitigation works can include, but are not limited to double glazing of windows, air conditioning and first flush systems fitted to water tanks.

If you would like to know whether your property lies in a Coal & Allied zone of mitigation, please contact our Communities Team on 1800 727 745 or email us at cnacommunityrelations@riotinto.com

To view the NSW Government Voluntary Land Acquisition and Mitigation Policy please visit http://www.planning.nsw.gov.au/Portals/0/DevelopmentProposals/IMP%20Voluntary%20Land%20Acquisition%20and%20Mitigation%20Policy%20SSD%20Mining.pdf

How do I make a complaint?

If you wish to submit a complaint by telephone, please call our complaint line at free call 1800 656 892. Please let us know if you would like us to call you back to discuss your complaint or provide feedback. 

How does weather impact noise from MTW?

Weather conditions experienced at MTW are considered typical for the Upper Hunter.

Wind patterns follow an annualised cycle predominantly blowing from the north-west during the cooler months, and from the south east during the warmer months. Wind direction is taken into account when measuring and understanding noise levels.

Temperature inversions are considered to be a feature of the region during Autumn nights, with potential to enhance noise transmission.

What happens when MTW receives a noise alarm?

MTW operates an alarm system in conjunction with the real-time directional monitoring network. Details on the configuration of the noise alarms can be found in the MTW Noise Management Plan. All alarms are investigated, and validated by hand held monitoring assessments by our CRO's. Where the CRO assessment identifies noise levels above the relevant noise limit, operational changes are introduced to reduce noise levels within 75 minutes.

How often is this website updated?

The InSite website is updated each business day for the previous day and night shift. Friday, Saturday, Sunday and Public Holiday Data is uploaded on the next business day.