Code of Maryland Regulations › Title 26 - DEPARTMENT OF ENVIRONMENT › Part 4 - SUBTITLES 19-30 › Subtitle 21 - MINING › Chapter 26.21.04 - Utilization of Coal Combustion Byproducts in Noncoal Surface Mine Reclamation › Section 26.21.04.06 - Leachate Control and Collection

Current through Register Vol. 51, No. 14, July 12, 2024
A. Minimum Requirements.
(1) The use of coal combustion byproducts in
				  the reclamation of a noncoal surface mine requires the installation of a liner
				  and leachate control and collection system that meets the minimum requirements
				  of this section.
(2) A liner system
				  shall be designed, constructed, and installed to facilitate collection of
				  leachate generated from the coal combustion byproducts to prevent migration of
				  pollutants to the adjacent subsurface soil, ground water, or surface water. The
				  subbase referenced below shall be constructed of natural earthen materials
				  which are excavated from on the site or which are imported from another
				  location, or of a synthetic or manufactured membrane material. The liner system
				  shall be:
(a) Constructed of materials that
				  have sufficient strength and thickness to prevent failure due to pressure
				  gradients, physical contact with the coal combustion byproducts or leachate,
				  climatic conditions, the stress of installation, and the stress of daily
				  operation;
(b) Constructed of one
				  or more unreinforced synthetic membranes with a combined minimum thickness of
				  50 mil, or a single reinforced synthetic membrane with a minimum thickness of
				  30 mil, which has a permeability less than or equal to 1 x
				  10-10 centimeters/second, placed over a prepared
				  subbase with a minimum thickness of 2 feet and a permeability less than or
				  equal to 1 x 10-5 centimeters/second, unless the
				  Department authorizes the installation of a liner system with specifications
				  different than those listed in this paragraph only upon a successful
				  demonstration by the permittee that:
(i) The
				  alternate system is capable of collecting and managing the leachate generated
				  at the site; and
(ii) The liner
				  system provides an equivalent level of protection to public health and the
				  environment;
(c) Placed
				  upon a foundation or base capable of providing support to the liner and
				  resistance to pressure gradients above and below the liner to prevent failure
				  of the liner due to settlement, compression, uplift, puncture, cutting, or
				  activities at the site;
(d)
				  Installed to cover all surrounding earth likely to be in contact with the coal
				  combustion byproducts or leachate;
(e) Installed with a minimum slope of 2
				  percent to facilitate movement of leachate towards the leachate collection
				  system and prevent leachate from ponding on the fill floor; and
(f) Located entirely above the composite high
				  water table and bedrock, with a minimum buffer distance of 3 feet between the
				  bedrock elevation and the maximum expected ground water elevation, and the
				  bottom of the liner system including the thickness of the prepared
				  subbase.
(3) A leachate
				  collection and removal system, located immediately above the liner shall be
				  designed, constructed, maintained, and operated to collect and remove leachate
				  generated from the coal combustion byproducts. The leachate collection and
				  removal system shall be:
(a) Constructed of
				  materials that are chemically resistant to the coal combustion byproducts and
				  the leachate expected to be generated, and of sufficient strength and thickness
				  to prevent collapse under the pressures exerted by overlying coal combustion
				  byproducts, cover and other materials, and by any equipment used at the
				  site;
(b) Designed and operated to
				  function without clogging; and
(c)
				  Designed and operated to ensure that the leachate depth over the liner does not
				  exceed 12 inches.