Groundwater levels in the mine workings under Bendigo are rising after the cessation of mine dewatering activities in the area by Unity Mining.
Greater Bendigo City Council has asked the Victorian Government to enable them to pump water into the Woodvale evaporation ponds as a short-term solution.
A council report states that groundwater levels are continuing to rise across the mine workings under Bendigo since Unity Mining ceased pumping water to Woodvale.
The water has high levels of salt, arsenic, and other metals and it is expected that surface discharge could occur as early as January.
“Ultimately, the levels will reach the surface and discharge water into the Sydney Flat Creek, which is connected to Myers Creek, the Bendigo Creek, and Kow Swamp; all heading for the Murray River system in the long run,” the report to Council states.
Pumping being undertaken by the Bendigo Trust is likely to avoid discharge into the Bendigo Creek in Golden Square and central Bendigo, but this might happen in the longer-term – a situation that the City of Greater Bendigo is keen to avoid.
Bendigo’s groundwater levels have been managed by Unity Mining and its predecessors over the past couple of decades through their need to pump water to Woodvale to enable further exploration for gold extraction under Bendigo. However, Unity Mining has now ceased its operations and stopped pumping water to Woodvale.
“Council has had ongoing discussions and negotiations between a number of stakeholders, including the State Government, about the need to act on addressing groundwater issues in Bendigo,” the report states.
“The Council understands that the only available option in the short term is to utilise assets owned by Unity Mining to transfer some of the groundwater to evaporation ponds at Woodvale, established and used for this purpose for many years. Council also understands that there has been discussion with the Woodvale community about the likelihood that pumping into the ponds would be required this summer to assist with managing the groundwater levels. This helps with some management of the water levels and with the dust control of the Woodvale ponds.”
“The Council advocates for this course of action to avoid groundwater discharge to Sydney Flat Creek. This is a short term measure and the matter will need further detailed investigation to find a long term solution to this problem. Ultimately, the Woodvale community would want to see the ponds decommissioned.”