UPDATE: 4.50pm, Friday, December 13.
The Bells Line of Road will be closed from 8am Saturday, December 14, between Mount Wilson Road and the Darling Causeway as firefighters continue to battle the Gospers Mountain blaze.
The road closure is expected to remain in place for up to four days, allowing authorities to undertake backburning operations during milder conditions in an effort to contain the fire.
HEIGHTENED activity of the Gospers Mountain bushfire on Thursday night saw the fire spot over containment lines north-east of Blackmans Flat.
The 362,117 hectare blaze, which was increased to 'watch and act' late Thursday afternoon, is now back at 'advice' level.
At 10pm on Thursday the fire was burning within five kilometres from Angus Place Colliery on Wolgan Road.
"The area is extremely smokey with visibility down to around 500 metres or less," NSW Rural Fire Service (RFS) Chifley/Lithgow district assistant Michael Dunn said.
"Residents moving around in the area should proceed with caution."
Areas burnt during the 2013 State Mine Fire are also providing some advantage by slowing fire progression.NSW Rural Fire Service Chifley/Lithgow district assistant Michael Dunn.
Aircraft will be used on Friday to help firefighters assess the fire's behaviour.
Mr Dunn said the strategy during coming days would be to continue back-burning operations heading west towards Clarence in order to strengthen the containment line.
"There are a number of pre-identified triggers that the planning team have in place to ensure that the works are carried out in advance of the fire advancing towards Bells Line of Road," he said.
"Areas burnt during the 2013 State Mine Fire are also providing some advantage by slowing fire progression."
Mr Dunn said higher humidity is slowing the back burns progress in this area, however this will also slow the southward movement of the fire edge.
"People in the communities along Bells Line of Road should expect to see an increase in fire activity as a result of the back burning operations," he said.
"Additional back burning will commence around the villages of Clarence and Dargan to create a containment line for the fire moving across from Newnes State Forest."
These operations will be ongoing as conditions allow.
Stay up to date with this fire and others in NSW at Fires Near Me.
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