There are fears a “mega fire” at Gospers Mountain could tear through a coal mine and a major power station north-west of Sydney this week, as temperatures soar to 46 degrees.

NSW Rural Fire Service volunteers managed to protect the Mount Piper Power Station, Springvale Coal Mine and the abandoned Wallerawang coal mines near Lithgow as embers rained down on them on Monday night.

RFS Deputy Commissioner Rob Rogers said crews remained on site to put out any embers that got into coal or vegetation.

“A lot of crews were deployed near that power station just to make sure the fire did not get into the coal,” he said.

“We will have crews there today (Tuesday) monitoring that condition just to make sure we do not have any problem fire starting.

“The last thing we need is something like that going.”

The Mount Piper Power Station generates about 10 per cent of NSW’s electricity and there is concern the fire could threaten power supplies in the region.

The Springvale coal mine has been closed since Thursday last week due to the risk of fire. Centennial Coal, which owns the mine, said stockpiles of coal were well protected behind containment lines.

“We are well prepared and well supported by the RFS and Fire and Rescue,” spokeswoman Katie Brassil said.

“We lost power to the mine last night, which means there has obviously been some damage to infrastructure.”

Ms Brassil said the mine had been forced to close, in part, because smoke had been sucked deep into it through the ventilation shafts.

Greenpeace Australia Pacific warned that if the fire took hold in the coal stockpiles it could burn for weeks and emit toxic fumes that would aggravate air pollution across Sydney and NSW.

The last time a coal mine fire took hold was in 2014 at Hazelwood in Victoria.

Spokesman Jamie Hanson said that fire burned for 45 days and produced toxic chemicals such as carbon monoxide and nitrogen oxide.

There is an increase in fire activity at the Gospers Mountain Fire near the intersection of Bells Line of Road and Mount Wilson Road. No properties directly under threat. #nswrfs @nswfires pic.twitter.com/q0jl9KE4wj — NSW RFS (@NSWRFS) December 17, 2019

A ‘monster’ fire

United States forestry worker Linda Chappell is spending more than a month in Australia helping firefighters, working as a strategic operations planner on the Gospers Mountain fire.

Ms Chappell said the fire was a “monster” but spending her Christmas in Australia was a chance to give back.

“We’ve had to have help from Australia before and my husband and I spoke about it and he said ‘boy they’ve showed up when you needed help and I said yep and he said let’s go’, and so we’re paying it back,” she told the ABC.

The RFS is bracing for a heatwave and strong winds that are expected to sweep through NSW on Thursday and Saturday.

Very hot and dry conditions and an elevated fire danger are forecast for parts of Sydney.

Penrith is expected to be one of the hottest parts of the state with 44 degrees forecast for Thursday and up to 46 predicted on Saturday.

Lithgow, where the Gospers Mountain blaze is burning, is predicted to reach 37 degrees on Thursday and 39 on Saturday. Parts of far western and southern NSW will reach well into the mid-40s.

The Gospers Mountain fire has already burnt through almost 400,000 hectares in multiple directions, and the RFS said it was likely to burn for “some weeks”.

-ABC