Waste Water Treatment Plant Upgrade

Leinster Nickel Operation

These works were completed in 2 stages. The first stage involved the excavation and installation of a new transfer tank, trenching for new services, backfill and compaction around the new tank, and installation of concrete around the tank surface for switch board mounting. The second stage involved the construction of two 3.6m high Concrete Tanks with a diameter of 15m each from the ground up. Steps included clearing of the construction area, exposing and relocation of buried services, removal of 4000 cubes of earth, steel fixing for walls, pouring walls and backfilling around the tanks once completed.

During completion of these works, several problems were encountered. Northfields WA was able to address these issues, while still managing to complete the works in a timely manner. Some of the issues and their resolution are listed below.

Northfields were required to remove part of the compound fence to make entry to the excavation area safe. The compound was required under government standards to be secure at all times. Northfields extended the compound with the use of their temporary fence panels.
Shortly after the excavation for the new tank was complete, the old system failed which led to the over flow of septic water into the excavation. Northfields were involved in the clean-up of the contamination and with reinstating the integrity of the excavation.

As the job neared completion, the Northfields bobcat ruptured a gas line while installing fence poles. The gas line was found to be in an area identified as having no existing services and which had been cleared for excavation. We were commended for our quick response and actions, which involved immediate shutdown and isolation of all vehicles, evacuation, and reporting of the incident. We were then involved in the sealing and repair of the leak following the clients safety procedures. The project was delayed by 90 days as the area had to be approved by the State Government for an environmental permit. Northfields brought in extra machinery and enlisted third party assistance to help bring the job back on track.

Old decaying explosives were found in close proximity to the construction site/township. Details of the find were immediately reported to the client and the area was evacuated. Northfields then carried out the correct steps in making the find safe as the explosives were found to be very unstable.

While the concrete pump was travelling from Perth to Leinster a bad section of road caused an electrical fault on the pump that couldn't be diagnosed by the electrical tradesperson in Leinster. This was diagnosed at 4pm the day before the pour. Northfields WA organized mobilization of another pump from Perth by 7pm with two drivers to ensure the safety of drivers from fatigue. This resulted in the concrete being poured as scheduled.