An alluvial aquifer is located in the eastern arm of a channel of the Hunter River. This provides potential groundwater connection between the Carrington Pit and the Hunter River.

The construction works comprise of the construction of a compacted clay buttress against the alluvial aquifer exposed in the highwall for the Carrington Pit and the installation of monitoring devices to measure the effectiveness of the structure in reducing seepage.

The barrier wall will also isolate the flow of contaminated groundwater through the overburden spoil towards the Hunter River upon cessation of mining and commencement of rehabilitation.

The compacted clay buttress (approximately 300,000 m3) stretches for 1.2km long by 15m high against the existing vertical highwall. Managing and coordinating Daracon plant fleet of in excess of 20 pieces of heavy equipment ranging from 825 Compactors, D7 Dozers, 140H Graders, 740 Watercarts and 8 articulated 40 ton dump trucks. A peak Daracon workforce of 40 were engaged on this project.

Project challenges include the moisture, conditioning, load & haul, placing and compacting of wet clayfill material in measured layers complete with geotechnical tests (over 800) of the individual layers.

Innovative construction practices and effective project management methodologies brought forward the project completion with a high level of Client satisfaction.