Living locally for over 55 years, I feel very strongly that you are letting people down if this plan goes ahead.
"National policy states that minerals extraction is not inappropriate in the green belt provided the openness of the green belt is preserved and where it would not conflict with the purposes of including land in the green belt."
It will greatly conflict with the current usage of the area. For over 50 years the area has been of great family use, both as farming and for everyday families to enjoy fresh air and get exercise. In this day of growing diabetes you are considering culling a prime area. Horse riders will be forced to again go into conflict with road users and vehicular traffic appertaining to site.