The process from mine to lake at Hazelwood

HAZELWOOD MINE TO BECOME LAKE

HOW LONG HAS IT OPERATED?

* Hazelwood has operated for more than 52 years.

* It supplies up to 25 per cent of Victoria's energy.

* When its closure was announced, it was employing 450 people directly and another 300 contractors.

WHY IS IT CLOSING?

* The ageing and increasingly inefficient plant is the most expensive brown coal station in Victoria.

* For safe and efficient operation, $400 million would need to be invested and owner Engie says that much investment is not viable.

* Engie is moving away from coal across international operations.

SHUTDOWN

* The first three generators were shut down on Monday, followed by three more on Tuesday and the final two on Wednesday.

* The business will close for good on Friday, March 31.

* Other shutdown processes, including draining fluids, removing oil and industrial gases, will continue until at least the end of May.

DECOMMISSIONING

* Involves containment of hazardous materials, disconnecting electrical supplies, cleaning, securing the site and salvaging.

* Expected to take about 12 months.

DEMOLITION

* Preparations will take about two years, including consulting with regulators and tendering contracts.

* Systematic demolition will take about three years.

REHABILITATION

* Engie estimates the mine rehabilitation process will cost about $439 million .

* Rehabilitation of an eastern part of the mine has already started.

* At least four years of rehabilitation is needed before the mine can be turned into a lake.

* Water may be sourced from underground aquifers, seepage, water entitlements and managed water from the Morwell Main Drain.

* Investigations are underway to see if Hazelwood's pondage, used to cool the plant, Eel Hole Creek and Morwell River can be used.

* A full-pit lake would take more than 10 years to fill using a range of water sources.

* A partial-pit lake created by pumping from the aquifer would take six years.

SOURCE: Engie