Doug Hood Mining

Stockton Mine – Earth dam and stormwater sump

June 12, 2023

The earth dam and stormwater containment sump constructed by Doug Hood Mining Ltd (DHML) at Stockton Mine are complete.

With a final crest level of RL737m, the 610,000 bcm dam embankment is 30 metres high.

Excavation of the mine water treatment sump called McCabes Sump by DHML provided the majority of the drilled & blasted rock for the dam. Sump construction is complete including inlet and outlet structures.

The bulk earthworks prime fleet was an EX1900 excavator (190 tonne) and 5 x 777D (100 tonne) dump-trucks, with the PC1250 excavator and A45G articulated dump-trucks used for fill placement on the narrowing final dam lifts.

A D9R bulldozer with GPS was used on the dam crest for fill push out and level control.  

Final batter trim was achieved with an EC380 excavator also fitted with GPS.

Articulated 45 tonne dump-trucks and smaller excavators were used when carting unsuitables from the dam footprint preparation, and other miscellaneous ancillary works associated with the various stages of dam construction

A D8T bulldozer followed by a D65 was used to track roll the final surface prior to the placement of the compacted fines layer.

A Montabert rock breaker fitted to an EC290 excavator was used to break up any oversize rock to incorporate in the dam fill lift layers and to make rip-rap for the spillway.

Finally a synthetic liner placed on a 200mm compacted fines layer was installed on the final upstream face by the client.

Spillway lined with a rip-rap layer

Close-up of completed embankment

Dam crest with final lift in progress

Trimming upstream batter and final lift placement

Dam floor clean-up of pockets of unsuitable materials & replacement with clean fill

Dam crest rising in background

D8T track rolling downstream batter slope

D8T track rolling upstream batter slope

Sump load-out with last flitch to complete dam crest

Sump floor with PC1250

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