Drayton Mine produces thermal coal and has been operating since 1983. It is situated in the Upper Hunter Valley, the largest coal-producing region in New South Wales, Australia.
The mine was supplying 1 Mt/y for a domestic power station contract – which was due to expire - and 4 Mt/y to service export contracts. Drayton Mine needed to modify the Coal Treatment Unit to increase export production capacity.
The existing plant bypassed 16 mm coal and only coarse coal was washed. The switch to all export contracts called for a full washing plant to beneficiate all the coal to lower the ash content to meet export requirements.
The upgraded plant also needed to meet stringent efficiency guarantees.
With more than a year to run on the domestic contract – and existing export agreements – it was critical that Drayton Mine’s commitments were not impacted by the Coal Treatment Unit upgrade work.
The Better Way
Anglo American engaged Ausenco QCC from the outset to conduct a series of Feasibility Studies for Drayton Mine. Through these studies, the team and Anglo American formulated a sound approach to address challenges around delivering a complex brownfields project efficiently – in a tight timeframe. An incentivised EPCM model was agreed upon, with both Ausenco QCC and Anglo American providing key resources and people to achieve the best results. The project was led by a Project Board, consisting of representatives from Anglo American and Ausenco QCC.
The plant was upgraded such that the +2 mm coal was processed by dense medium cyclone and the fines were deslimed and processed by two stages of Teetered Bed Separator.
The plate-shaped fine rejects, that reported to the thickener, caused blockages in the tailings line. The team successfully resolved the challenge by reducing the percentage of solids in tailings – through decreasing desliming screen aperture size and increasing tailings line flow velocity.
The team focussed on the risk register and operational readiness throughout the project execution to ensure a smooth transition into operation.
We developed the design and construction schedule to support existing operations, minimising disruptions to production, while still delivering the upgrade in time for the new export sales.
The plant operated beyond its required capacity of 700 t/h, achieving efficient operation at up to 850 t/h. All Performance Guarantee Criteria were met and the project was delivered without Lost Time Injury ahead of schedule – and below budget – in 2011.
The incentivised EPCM model enabled Ausenco QCC and Anglo American to face all project challenges as a team, leading to significant safety, technical, financial and timing outcomes.