Legacy mine inventory and current projects
An inventory of legacy mine sites is currently being developed. The inventory will identify high risk sites with the potential to cause significant environmental impact.
The inventory and associated risk based assessment will be used to determine priority sites and the allocation of resources.
The inventory project is progressing towards maturity and has required considerable time and resources to develop due to the remote locations of many of the sites and the limited access during the wet season.
The inventory will be dynamic and will continually evolve as site conditions change and further information becomes available.
Current work program
While the inventory is being developed, the unit has commenced work programs at sites known to be high risk.
Monitoring equipment was installed at four sites across the Northern Territory in 2014.
Stations provide real-time data on environmental conditions such as pit water level, electroconductivity, creek flow and weather. Real time remote monitoring offers the opportunity to access data over the wet season that would have previously been near impossible to collect.
Mine shaft remediation
As a priority, significant resources have been focused upon addressing public safety issues associated with abandoned open mine workings. The current program of safety works commenced in 2015. Works generally include a combination of shaft capping, backfilling, fencing, signage and adit grates. Mine shafts present a significant public safety risk and have been given a high priority for remediation.
Works have now been completed at Fossicking Area 4, Eldorado Area, Burnt Shirt Area and several areas near to town have been completed in Tennant Creek. Further works have been completed in the Hatches Creek area the Arltunga Historical Reserve. More than ninety open mine workings had been made safe by the end of 2017.
Ongoing works are planned as part of a four year public safety program in the Tennant Creek and surrounding areas. Further works are planned for the Tennant Creek, harts Range and Winnecke Goldfields areas.
Tennant Creek Safety Works Program
Kathleen Mine, Tennant Creek
Many of the legacy mine tenements are infested with weeds. Weed control and surveys on selected mining tenements around Tennant Creek commenced in late 2015. A baseline weed survey has also been completed at the former Goodall Mine Site.
Jululikari Ranger conducting weed control
A dust survey at the Peko Mine Site was commenced in 2016 to determine if there is the potential for human health impacts from windblown tailings. A monitoring network was set up to collect continuous dust monitoring data. The final report including results from the monitoring and air quality modelling was provided in 2018.
A groundwater investigation is being undertaken at the Redbank Mine Site to determine the mechanisms for seepage of contaminated water into the receiving environment. The site investigation works included an electromagnetic survey and hydrogeological drilling program which provided further information about hydrogeological conditions and a more extensive monitoring network in the shallow aquifer. Monitoring of groundwater from the installed monitoring wells is ongoing.
A fish survey was commenced in 2016 in response to concerns raised by traditional owners about potential risks to human health from consuming fish and molluscs in the creeks downstream of Redbank. Consultations were made with the Traditional Owners to help understand the cultural, harvesting and consumption aspects of aquatic species. Two rounds of aquatic biota sampling have been completed from permanent river pools using a combination of fishing methods. Laboratory analysis has been completed of fish, water and sediment samples. The final project report is expected to be completed in early 2018.
A detailed bathymetric survey of the flooded pit at Redbank was undertaken to collect accurate high resolution data of the pit to produce a digital terrain model of the submerged pit envelope. The survey also quantified the volume of water contained in the pit.
Hazardous materials survey
A survey of hazardous materials including asbestos containing materials located within the abandoned process plant and site infrastructure at Redbank was completed in 2016. An asbestos materials register was produced. The results of the survey will inform the management of materials on the site during future works.
Stock proof fencing was installed at Redbank and Goodall mine sites in 2016. The main objective of the fences is to restrict stock access to the sites which contain potentially contaminated areas. The fences also act as a fire break around the sites. A stock exclusion fence has also been constructed around the Warrego mine site west of Tennant Creek in partnership with Emmerson Resources.
Disposal of abandoned site infrastructure
The disposal of abandoned mining equipment located at the Redbank Mine Site is planned for 2018. A public auction of equipment is planned for mid-year, followed up by the demolition and disposal of the process plant and site infrastructure. Demolition will clear the way for further site remediation activities.
Since 2016 an Unmanned Aerial Vehicle (Drone) has be used to collect high resolution aerial photography. The Drone has increased safety and reduced site inspection time in the field by allowing inspection by camera first and then only walking to locations requiring further inspection.
Harts Range – Rex Mine - UAV Video – Area of Proposed Safety Works
Harts Range – Mount Palmer Mines – UAV Video - Area of Proposed Safety Works