Q. What is the conceptual final landform design proposed for the Project?
A. Shenhua Watermark will maximise opportunities for a post mining landscape that is generally consistent with the pre-mining land use, topography, biodiversity and visual aesthetics.
The mine plan for the Project was specifically redesigned so that the two largest voids created by operations in the Eastern Mining Area and the Southern Mining Area can be completely backfilled and rehabilitated. A third, much smaller, residual void has been engineered in the Western Mining Area so that it is remote from the black soil plains and groundwater aquifers.
Q. What will be the expected water level and quality of the final void lake?
A. Limited surface water runoff and groundwater seepage will fill the Western Mining Area void creating a lake following the cessation of mining. The freeboard between the final water level surface and the void spill height is approximately 40m, thereby meaning the final void will never overflow.
The salinity in the final void will increase at a rate of approximately 6,000 mg/L per 100 years, reaching approximately 32,500 mg/L after 500 years. The open void will remain a permanent sink for groundwater flow and the saline water that will develop within the void lake will not be able to flow to the adjacent alluvial aquifers.
Q. When will rehabilitation take place ?
A. The mining areas, excluding the final void in the Western Mining Area, will be progressively
rehabilitated as mining advances and concludes.