After eights hours of debate, the authority’s planning committee voted on a resolution to approve the application put forward by York Potash.
Of 23 members on the authority, 15 were at the meeting and it was carried with eight in favour and seven against.
There were cheers of celebration from inside the meeting room where the 60 people employed by the York Potash project were looking on. They were echoed by screams of delight from members of the public who were watching from an adjacent room via video link.
It has been four years in the making after plans for the mine were first revealed. It is expected works at the former Dove’s Nest Farm site in the village of Sneatonthorpe near Whitby will start later this year or early in 2016.
An underground pipeline to transport the mined fertiliser product polyhalite to a plant on Teesside will follow.
After the meeting, which ran at Sneaton Castle until almost 7pm, Chris Fraser, the managing director or Sirius Minerals - the parent company to York Potash - emerged from the meeting to cheers from staff.
He told The Yorkshire Post: “We are obviously very happy. A lot of hard work and sleepless nights have gone into this. We got there in the end by only one vote but that is all you need and we will go and celebrate, as we should.
“But as one of my directors said - this is only the end of the beginning and we get on with the real job of raising the funds and building the project.”
He added: “The authority did a great job of getting through it with all the support in the room for and against. The chair did a good job and members gave it a thorough debate.”
The crux of the debate had been whether the benefits could justify the environmental and visual impact on the landscape.
Members spoke at length about tourism as Whitby’s main industry not being sustainable but also how the National Park’s prime aim was to protect the landscape.
Andy Wilson, chief executive of the North York Moors National Park Authority said: “It was a close vote and we are conscious of that but members thought this was the exception because it is a once in a several generations opportunity.”
However, the Campaign For National Parks organisation said it would be calling for a public inquiry and failing that will launch a legal challenge as a last ditch resort to halt the project.
Ruth Bradshaw, Policy and Campaigns Manager, said: “There was clear evidence of the planning grounds for refusing this but there has also been huge pressure to approve a project widely promoted as bringing employment to the area, even though many of the jobs will not go to local people. We are confident any public inquiry would result in today’s decision being overturned so we can finally see an end to this threat to the North York Moors.”