Dalrymple Bay coal terminal rail loop dam and quarry dam civil works
In February 2015, Dalrymple Bay Coal Terminal (DBCT) embarked on a Water Quality Improvement Project to enhance and increase the management of water on site. Located at the Port of Hay Point, DBCT is part of one of the largest coal exporting ports in the world. The Terminal is a common user facility owned by the State Government of Queensland and leased to Dalrymple Bay Coal Terminal Management.
Golding was engaged to carry out a $21.7m construction of a rail loop and quarry dam raising. This involved the construction of a new eastern storage dam with the DBCT Rail Loop as well as the diversion of Grendon Creek and raising of the dam embankment west of the coal stockyard. Golding’s project scope included the completion of more than 750,000m3 of bulk earthworks, 400,000t material processing and 600,000m3 of zoned embankment construction and associated concrete structures and pipework.
This project was particularly challenging from an earthmoving perspective as all of the material in the Rail loop was site won and processed material. This resulted in complex material management as every cubic meter of earth needed to be classified into one of the seven different material types and a suitable location had to be found to place the material. Adding to the complexity was that the in situ material had to be moved before the reclassified material could be placed resulting in a complicated “chess” game with the aim of minimising rehandling.
A further complication was the manufacture of material type 3A (200mm minus Graded rock) and 2B (Type 2.5) from the rock material. A material processing operation was setup, stockpile areas established, source material won and delivered for processing and then the entire operation would be relocated once the source supply was exhausted to commence again.
A detailed material management plan was required, incorporating significant amounts of additional geotechnical investigation, once on site, to more accurately determine where the various material types were, and the quantities available. Material management planning and the ability to respond effectively when the material actually encountered, varied from what was anticipated and was critical to the project’s success.
The Terminal now has over 700 million litres additional storage capability for stormwater on site at its disposal, providing significant cost savings and environmental benefit.