To ensure Meandu Mine continued to meet their Environmental Discharge requirements Dowdens designed and incorporated 4x Settling Pits and 3x Oily Water Separators into the construction of the Heavy Vehicle Wash Bay. In Queensland, it is a legal requirement for mine sites to treat (separate) any sludge or oil from any wastewater coming from a Heavy Vehicle Wash Bay.
Pictured below you can see the 4x large Settling Pits (empty) that are used to catch and store (via gravity feed) wastewater from the Wash Pad area. The wastewater generally contains some grease, oil, coal fine and soil (mud). The coal fine, mud and other solid particles washed off the trucks are allowed to settle to the bottom of the Settling Pits – the pits are then intermittently emptied by a Bobcat excavator.
The wastewater (still containing grease and oil) is pumped from the Settling Pits via progressive cavity pumps into 3 individual ‘Oily Water Separators’ to remove the remaining contaminants. Once the wastewater has been through this treatment stage it is pumped back into Meandu Mine’s network of onsite holding dams to be used in other site extraction and processing applications.
Dowdens design philosophy for this project was:
