405 KAR 3:180. Coal waste dams.

 

      RELATES

TO: KRS 350.151

      STATUTORY

AUTHORITY: KRS 350.151

      NECESSITY,

FUNCTION, AND CONFORMITY: KRS 350.151 requires the Environmental and Public

Protection Cabinet to adopt rules and administrative regulations for the surface

effects of underground coal mining. This administrative regulation sets forth

requirements for the design, construction, maintenance and reclamation of coal

waste dams.

 

      Section

1. General. No waste material shall be used in existing or new dams without the

approval of the cabinet. The permittee shall design, locate, construct,

operate, maintain, modify, and abandon or remove all dams (used either

temporarily or permanently) constructed of waste materials, in accordance with

the requirements of this administrative regulation.

 

      Section

2. Construction of Dams. (1) Waste shall not be used in the construction of

dams unless demonstrated through appropriate engineering analysis, to have no

adverse effect on stability.

      (2)

Plans for dams subject to this section, and also including those dams that do

not meet the size or other criteria of 30 CFR 77.216(a) shall be approved by

the cabinet before construction and shall contain the minimum plan requirements

established by the Mine Safety and Health Administration pursuant to 30 CFR

77.216-2.

      (3)

Construction requirements are as provided in this subsection:

      (a)

Design shall be based on the flood from the probable maximum precipitation

event unless the permittee shows that the failure of the impounding structure

would not cause loss of life or severely damage property or the environment, in

which case, depending on site conditions, a design based on a precipitation

event of no less than 100-year frequency may be approved by the cabinet.

      (b)

The design freeboard distance between the lowest point on the embankment crest

and the maximum water elevation shall be at least three (3) feet to avoid

overtopping by wind and wave action.

      (c)

Dams shall have minimum safety factors as provided in the following table:



Case





Loading Condition





Minimum Safety Factor







I





End

of construction





1.3







II





Partial

pool with steady seepage saturation





1.5







III





Steady

seepage from spillway or decant crest





1.5







IV





Earthquake

(cases II and III with seismic loading)





1.0





      (d)

The dam, foundation, and abutments shall be stable under all conditions of

construction and operation of the impoundment. Sufficient foundation

investigations and laboratory testing shall be performed to determine the

factors of safety of the dam for all loading conditions in this administrative

regulation and for all increments of construction.

      (e)

Seepage through the dam, foundation, and abutments shall be controlled to

prevent excessive uplift pressures, internal erosion, sloughing, removal of

material by solution, or erosion of material by loss into cracks, joints, and

cavities. This may require the use of impervious blankets, pervious drainage

zones or blankets, toe drains, relief wells, or dental concreting of jointed

rock surface in contact with embankment materials.

      (f)

Allowances shall be made for settlement of dams and foundations so that the

required freeboard will be maintained.

      (g)

Impoundments created by dams of waste materials shall be subject to a minimum

drawdown criteria that allows the facility to be evacuated within ten (10) days

by spillways or decants of ninety (90) percent of the volume of water stored

during the design precipitation event.

      (h)

During construction of dams subject to this administrative regulation the

structures shall be periodically inspected by a registered professional

engineer to ensure construction according to the approved design. On completion

of construction, the structure shall be certified by a registered professional

engineer experienced in the field of dam construction as having been

constructed in accordance with accepted professional practice and the approved

design.

      (i)

A permanent identification marker, at least six (6) feet high that shows the

dam number assigned pursuant to 30 CFR 77.216-1 and the name of the person operating

or controlling the dam, shall be located on or immediately adjacent to each dam

within thirty (30) days of certification of design pursuant to this

administrative regulation.

      (4)

All dams, including those not meeting the size or other criteria of 30 CFR

77.216-1, shall be routinely inspected by a registered professional engineer,

or someone under the supervision of a registered professional engineer, in

accordance with Mine Safety and Health Administration regulations pursuant to

30 CFR 77.216-3.

      (5)

All dams shall be routinely maintained. Vegetative growth shall be cut where

necessary to facilitate inspection and repairs. Ditches and spillways shall be

cleaned. Any combustible materials present on the surface, other than that used

for surface stability such as mulch or dry vegetation, shall be removed and any

other appropriate maintenance procedures followed.

      (6)

All dams subject to this administrative regulation shall be certified annually

as having been constructed and modified in accordance with current prudent

engineering practices to minimize the possibility of failures. Any changes in

the geometry of the impounding structure shall be highlighted and included in

the annual certification report. These certifications shall include a report on

existing and required monitoring procedures and instrumentation, the average

and maximum depths and elevations of any impounded waters over the past year,

existing storage capacity of impounding structures, any fires occurring in the

material over the past year and any other aspects of the structures affecting

their stability.

      (7)

Any enlargements, reductions in size, reconstruction or other modification of

the dams shall be approved by the cabinet before construction begins.

      (8)

All dams shall be removed and the disturbed areas regraded, revegetated, and

stabilized before the release of bond unless the cabinet approves retention of

such dams as being compatible with an approved postmining land use.

                (9) Coal

waste dams (except those classified as Class (A) pursuant to 405 KAR 3:020,

Section 5(2)(d)) constructed pursuant to this administrative regulation shall

be approved by the cabinet, designed, constructed and maintained according to

the provisions of KRS 151.250 and administrative regulations adopted pursuant

thereto. (4 Ky.R. 422; eff. 5-3-78; Am. 526; 5 Ky.R. 232; eff. 8-23-78; TAm

eff. 8-9-2007.)