MAILBOX

June 2013 Newsletter

MINING UPDATE

MANDALONG SUBSIDENCE UPDATE

Mandalong Mine is currently mining its 14th longwall panel since commencing operations in 2005. Starting near the intersection of Sauls Rd and Walls Lane the extraction of longwall 14 commenced in February 2013. It will finish on the eastern side of Mandalong Rd and Browns Road intersection in August this year. It will then take approximately a month for the longwall equipment to be relocated to Longwall 15, which is expected to commence production in September.

Mandalong has recently taken delivery of two new continuous miners to support the development of the over 20km of roadways needed annually to ensure the mines continued smooth operations and timely longwall moves. Mandalong produced 5.44 million tonnes of coal in 2012 and is expected to produce 5 million tonnes in 2013.

Mandalong mine has over 55km of established subsidence monitoring lines over the mining area to monitor the level of surface subsidence on the land, homes, dams, wetlands and infrastructure. The monitoring lines typically consist of 1.8metre steel star pickets driven into the ground and covered with a steel cover. The monitoring points are typically located at 10m intervals along the centre of each longwall panel (centrelines) or at right angles to the longwall (crosslines). Subsidence is measured by undertaking pre-mining surveys and recording the original height of each monitoring point. Following mining, the subsidence lines are re-surveyed and the height of each monitoring point again recorded. The difference in height is the amount of vertical subsidence at that point.

The distance between the monitoring stations are also measured before and after mining. As the ground subsides, it bends, causing the surface to either increase or shorten in length over the area affected. The change in length between monitoring points is calculated to measure ground strain. The amount of tilt between points is also calculated, which shows the change in the slope of the ground surface. Tilt is calculated by measuring the change in vertical height, divided by the distance between the monitoring points, expressed in mm/m.

Subsidence lines and monitoring frequency are approved the Department of Resources and Energy (DRE) and the placement of subsidence lines is determined in consultation with DRE, infrastructure owners, geotechnical consultants and landowners.

Mandalong Mine uses a Compliance Database to schedule the timing of each survey to ensure all surveys are undertaken at the appropriate time. The results of each survey are reviewed by the Survey Department and the Mining Approvals Coordinator. The monitoring results are then forwarded within 48 hours of the survey being undertaken to DRE, the Mine Subsidence Board and infrastructure owners for external review. A review of these results is also conducted at the completion of each longwall panel to analyse and update Mandalong’s subsidence prediction model.

Monitoring has shown that subsidence is now complete over Longwalls 1 to 10. After consultation with the DRE, removal of the majority of subsidence lines over Longwalls 1 to 4 has been approved and is currently in progress although, some monitoring lines over these longwall panels will remain for the life of the mine.

SUBSIDENCE MANAGEMENT PLANSThe Subsidence Management Plan (SMP) application for Longwalls 18 to 21 commenced in January this year, with the format and process similar to previous applications. All landowners within the application area were sent a mining notification that included information on the SMP process, the expected impacts of longwall mining in the region and legal advice on landowner’s rights and the company’s obligations. Centennial also offers upfront funds to all affected landowners for initial legal advice on the development of the landowner’s Property Subsidence Management Plan (PSMP). This assistance also acknowledges the landowner’s time in reviewing the documents and meeting with company representatives.

Currently, Mandalong is in the process of consulting with landowners, outlining proposed mining, subsidence predictions for their property and development of their PSMP. A number of studies encompassing flora, fauna and land use may be included in the development of each PSMP. Where studies are required by qualified consultants, they are facilitated by a standard Centennial Coal Access Agreement which formalises the conditions of entry to private property, the scope of work to be conducted, compensation and indemnifies the landowner.

Other studies and assessments undertaken as part of the SMP application include the impact of subsidence on groundwater, flooding, wetlands, cultural heritage and infrastructure. If you have any questions regarding the SMP or mining process, please contact the Mining Approvals Coordinator, Phil Enright, on 4973 0948.

MANDALONG GAS CONVERSION PROJECTSAs we mine coal methane gas is released. Methane is an inherent gas in coal and its proportion or ‘gassiness’ is particular to individual mines. Methane is present in reasonable quantities at Mandalong and requires management. Our mine workings are ventilated by fans that draw fresh air through the mine. This provides air to workers but also drains inherent gases, such as methane out of the mine.

Methane is removed in two ways at Mandalong. The first is by ‘pre-draining - the gas which involves drilling ahead of the longwall areas to release the gas. This is a high concentration form of methane. The second is by the mine fans. This is diluted methane (low concentration) and is known as Ventilation Air Methane (VAM).

Methane, whilst hazardous in an underground mine, is also a greenhouse gas when emitted to the atmosphere. Mandalong is nearing completion of two projects that will reduce its greenhouse gas emissions of methane.

Ventilation Air Methane Regenerative After Burner Mandalong Mine, in partnership with Coal Innovation NSW and Corky’s Sustainable Energy, will trial a new methane gas conversion system, VAM-RAB (Ventilation Air Methane Regenerative After Burner).

This research and development project addresses methane in its diluted form (VAM). VAM is the largest component of Mandalong’s greenhouse emissions, but also poses the biggest technological challenge. At this point there is no proven, safe and efficient mechanism to remove methane from VAM. The VAM-RAB research and development project aims to trial technology that if successful may be up-scaled and commercialised.

The trial is primarily about proving the technology works, but will also reduce the sites greenhouse emissions by around 2%.

The commissioning of the VAM-RAB facility is expected to be completed in the second half of this year.

Gas Flare Project

The high concentration ‘pre-drainage’ gas will be converted to carbon dioxide in an enclosed flare. This reduces the potency as a greenhouse gas. Civil works for construction of the gas flares commenced in October 2012 and it is anticipated to be operating by the middle of the year. When in full operations, the flare should reduce the mine’s greenhouse emissions by around 12%.

MANDALONG MINE EXPLORATIONAn Exploration Review of Environmental Factors (REF) modification was approved by the Department of Resources & Energy (DRE) in April 2013 for an additional 24 bore holes to be drilled at 19 sites within Mandalong’s exploration area. The REF modification document is available on Centennial’s website.

Drilling activities will be undertaken 7am - 6pm, Monday to Friday and 8am - 1pm on Saturday with no work on Sunday or Public Holidays. Any work outside these times can only occur with the landholder’s consent and notification to neighbouring property owners. Consultation with relevant landowners has commenced.

If you have any questions on the drilling programme, contact the Mandalong community enquiries line on 1300 730 919.

VAM-RAB under construction

MANDALONGCOMMUNITY INFORMATION LINE

1800 730 919

www.centennialcoal.com.auCover photo: Kangaroos on Mandalong’s Pit top

MANDALONG’S NESTING PROGRAMIn 2010, the Mandalong Mine developed a comprehensive research program to better understand the use of nesting boxes.

150 nesting boxes have been installed along Centennial’s private haul road to replace the hollow trees which were removed during its construction.

“During construction we removed around 90 hollow trees, which acted as habitats for fauna. To replace these habitats, we have applied research to determine where we should install the nesting boxes,” said Centennial’s James Wearne.

The research program provides an in-depth look at the nesting box system as there has been little research performed to understand what factors may influence different species to use the nesting boxes.

“Since we have installed and monitored the nesting boxes, we have seen great results, with an increase in different species using the boxes. Research shows that this is due to the design of the boxes and the aspects they face,” continued James.

The nesting boxes house a variety of fauna including possums, gliders and various bat species and are being used for shelter, rearing young and feeding.

The boxes are monitored twice a year and feature infra-red motion cameras to collect further information on the use and factors that may explain why they are inhabited.

LOCAL COMMUNITY SUPPORTMandalong continues to actively engage with and invest in the community in which it operates. The mine supports numerous community organisations and events including the; Lake Macquarie School Environment Awards, Camp Quality Golf Day, Morisset Community Festival, Morisset Masonic Centre’s hall upgrade, Morisset United Soccer Club, Westpac Rescue Helicopter Service, Meals on Wheels, Morisset Pro Am, Paddlefest, Morisset/Lake Macquarie Agricultural Show Association Showgirl competition, St. John Vianney Primary School “swale” project, the Yula-Punaal Aboriginal Corporation’s bush tucker garden, and the Southlake Christmas Spectacular.

Gould’s long eared bats found in the nesting boxes