The official line its that they have stopped mining because it wasn't making any money, and they need to focus on making a 'section 73' application. This is basically a request to vary the planning consent which they already have so that it better reflects the way they are actually operating.
As Chairman of the Parish Council for the village where the mine is located, I am in regular contact with both the Mine's management and the PDNPA. This is not an appropriate forum in which to go into detail but suffice it to say that to characterise the closure as being all the fault of the Peak Park Authority is not accurate, by quite a long way.