As used in this article:

(1) "Active coal mining property" means a mineable bed of coal on a property or portion of a property involved in a permitted mining operation. Each and every bed of coal being mined in a permitted mining operation is a separate active mining property.

(2) "Industrial property" means the real and personal property integrated as a functioning unit intended for the assembling, processing and manufacturing of finished or partially finished products.

(3) "Managed timberland" means surface real property, except farm woodlots, of not less than ten contiguous acres which is devoted primarily to forest use and which, in consideration of its size, has sufficient numbers of commercially valuable species of trees to constitute at least forty percent normal stocking of forest trees which are well distributed over the growing site, and that is certified as managed timberland by the Division of Forestry.

(4) "Natural gas-producing property" means the property from which natural gas has been produced or extracted at any time during the calendar year preceding the assessment date. Natural gas producing-property includes the property interest or interests underlying an area of up to one hundred twenty-five acres of surface per well for property with active wells on the parcel.

(5) "Natural resources property" means any of the following: Active coal mining property, reserve coal property, natural gas-producing property, oil-producing property, managed timberland or other natural resources property.

(6) "Oil-producing property" means property from which oil has been produced or extracted at any time during the calendar year preceding the assessment date. Oil-producing property includes the interest or interests underlying an area of up to forty acres of surface per well with one or more active wells on the parcel.

(7) "Operator" means an individual, limited liability company, partnership, corporation, joint venture or other enterprise which proposes to or does locate, drill, produce, manage or abandon any oil and/or natural gas well or which is engaged in actively obtaining or preparing to obtain coal and/or its by-products from the earth's crust on an active coal mining property.

(8) "Reserve coal property" means any property for which coal rights are part of the owned estate and which is not part of an active coal mining property.