Minn. Stat. § 272.04: MINERAL, GAS, COAL, AND OIL OWNED APART FROM LAND; SPACE ABOVE AND BELOW SURFACE.

Subdivision 1. Mineral, gas, coal, oil interests.

When any mineral, gas, coal, oil, or other similar interests in real estate are owned separately and apart from and independently of the rights and interests owned in the surface of such real estate, such mineral, gas, coal, oil, or other similar interests may be assessed and taxed separately from such surface rights and interests in such real estate, including but not limited to the taxation provided in section 273.165, subdivision 1. All laws for the enforcement of taxes on real estate apply to such interest.

Subd. 2. Right to use air space or below surface.

When the right to use the air space above or subsurface area below any real estate is conveyed by an owner to another person, partnership or corporation, such right shall constitute a separate interest in real estate which may be assessed and taxed separately from other rights in such real estate. All laws for the enforcement of taxes on real estate shall apply to such rights.

Subd. 3. Leases.

When the right to use air space above or subsurface area below real estate is granted by a lease for a term of three or more years, by the state or an agency or subdivision thereof, by an institution whose property is exempt from taxation, or by a taxpayer whose property is not taxed in the same manner as other property, such right to use air space or subsurface area shall constitute an interest in real estate which may be assessed and taxed separately, notwithstanding any law to the contrary. All laws for the enforcement of taxes on real estate shall apply to such leased property.