Chapter 29 ZONING*
Section 29-20.1 District M-U, Underground space.
(a) Definition. Underground space is hereby defined as the entire cavern
resulting from the
extraction of subsurface-located material in such a manner that the surface area of the property is
not disturbed except in the vicinity of the entrances and easements servicing the development.
(b) Purpose. District M-U is established for the following purposes:
(1) To accommodate and permit the use of underground
(2) To protect any other properties and persons from
adverse effects caused by activities in
underground space; and
(3) To protect the health, safety and welfare of persons
in or around underground facilities.
(c) Conditions for Establishing District M-U.
(1) District M-U shall be permitted only where the primary
entrance is located in district M-1 or M-C, and:
a. Where usable underground space
b. Where material intended to
be extracted exists adjoining an existing district M-U, M-1
(2) Any application for a change in zoning to district
M-U shall include a certified survey
map showing the extent of existing underground mining and all points of access to the surface
whether they be vehicle entrances or other entrances for ventilation or utility purposes.
(d) Permitted Uses. In district M-U, no building, land or premises shall
be used and no
building or structure shall hereafter be erected, constructed or altered except for one or more of
the following uses:
(1) All permitted uses in the zoning district controlling
the surface property at the primary
entrance to district M-U. The primary entrance is determined to be that having the most intensive
(2) Extraction of limestone or other subsurface materials.
(e) Standards and Requirements. Underground space in district M-U is
authorized to develop
in accordance with the provisions herein, subject to the following standards and requirements:
(1) Location. Underground development districts
shall apply only to the subsurface of
property under the same ownership as the surface property, and will not affect the zoning district
or districts designated for the surface above district M-U.
(2) Access. The access to all districts M-U shall
be through property owned or controlled by
the owners or operators of the underground space.
(3) Building permits. Where applicable, underground
space must have a building permit to
develop a habitable underground building and to qualify for a certificate of occupancy.
(4) Safety. The owners or operators of underground
space shall file with the department of
a certificate by a registered professional engineer as to the structural
integrity of the underground space. Such certificate may provide for exceptions or conditions
which must be adhered to as a condition of building permit approval. Such certificate shall be
valid for newly added, or mined-out areas, if it is so described in the certificate. Such certificate
must have been dated within the past ten (10) years to be valid for its application to new areas.
(5) Surface zoning exclusion. With the exceptions
as noted herein, all districts M-U as they
are created are separated from the provisions of the surface zoning districts, even though they
may underlie them.
(6) Surface and special easements. Penetrations
from district M-U to the surface property
above it shall be permitted without regard to the provisions of the surface zoning district,
provided that such penetrations are for the purpose of connecting utilities or to contain safety,
relief or life-support systems to the underground. All penetrations must be contained within a
public easement to assure perpetuity and continued service to the underground development.
(Ord. No. 10847, § 1, 1-6-86; Ord. No. 21095, § 13, 9-19-11)
(Ord. 21095, Amended, 09/19/2011, Prior Text)