(a)
Prevailing hydrologic balance. Underground mining activities
shall be planned and conducted to minimize changes to the prevailing hydrologic
balance in both the permit and adjacent areas.
(b)
Minimum requirements. At
a minimum, water which is discharged or is permitted to flow from areas
disturbed by underground mining activities, including areas disturbed by
mineral preparation, processing or handling facilities, shall be passed through
a sedimentation pond or treatment facility before discharging, except as
provided in subsection (j).
(c)
Effluent limitations. A person may not allow a discharge of
water from an area disturbed by underground mining activities, including areas
disturbed by mineral preparation, processing or handling facilities which
exceeds the following groups of effluent standards. The effluent limitations
shall be applied under subsection (d).
Group A
Parameter
|
30-day Average
|
Daily
Maximum
|
Instantaneous Maximum
|
iron (total) |
3.0 mg/l |
6.0mg/l
|
7.0 mg/l |
manganese (total) |
2.0 mg/l |
4.0
mg/l |
5.0 mg/l |
suspended solids |
35 mg/l |
70
mg/l |
90 mg/l |
pH
1
|
greater than 6.0; less than 9.0 |
alkalinity greater than acidity
1
|
1 The
parameter is applicable at all times. |
Group B
Parameter |
Instantaneous
Maximum |
iron (total) |
7.0 mg/l |
settleable solids |
0.5 ml/l |
pH |
greater than 6.0; less than
9.0 |
alkalinity greater than acidity |
Group C
Parameter |
Instantaneous
Maximum |
pH |
greater than 6.0; less than 9.0 |
alkalinity greater than acidity |
(d)
Limitations. The
effluent limitations and precipitation exemptions are as follows:
(1) The discharges specified in this
subsection shall comply with the effluent limitation in this subsection:
Type Discharge
|
Precipitation Event
|
Effluent
Limitations
|
Drainage from underground mine
workings |
all |
Group A |
Surface runoff from active
area |
dry weather |
Group A |
less than or equal to 10yr-24hr |
Group
B |
greater than 10yr-24hr |
Group C |
Surface runoff from area where
Stage 2 standards achieved |
dry weather |
Group A |
less than or equal to 10yr-24hr |
Group
B |
achieved greater than 10yr-24hr |
Group
C |
All other discharges |
dry
weather |
Group A |
less than or equal to 10yr-24hr |
Group
B |
greater than 10yr-24hr |
Group C |
(2) To be entitled to the effluent
limitations in Group B or Group C, the permittee shall comply with §
89.53 (relating to precipitation
event exemption).
(e)
Exceptions to effluent limitations. Exceptions to effluent
limitations are as follows:
(1) The pH of
water being discharged shall be maintained between 6.0 and 9.0 except in the
following circumstances:
(i) The operator
demonstrates that the wastes are discharged to an acid stream in which cases
the pH may be greater than 9.0.
(ii) The operator affirmatively demonstrates,
in writing, to the Department that biological respiration in the wastewater
treatment system will cause the discharge to exceed the limits in this section
and that exceeding these limits will not result in a violation of applicable
water quality standards in Chapter 93 (relating to water quality standards) or
of the applicable treatment requirements and effluent limitations to which a
discharge is subject under the Clean Water Act (33 U.S.C.A. §§
1251-
1376), in which case the
Department may grant a variance in writing from the limitation in this
section.
(iii) The operator
affirmatively demonstrates to the Department that the wastewater treatment
process being used by the operator requires the pH to be raised above 9.0, that
the elevated pH will not cause a safety hazard at the outfall and that the
elevated pH will not result in a violation of applicable water quality
standards in Chapter 93 or of the applicable treatment requirements and
effluent limitations to which a discharge is subject under the Clean Water Act,
in which case the Department may grant a variance from this
limitation.
(2) When a
discharge without chemical or biological treatment has a pH greater than 6.0
and a total iron concentration of less than 10.0 mg/l, the manganese limitation
does not apply.
(f)
Postmining pollutional discharges.
(1) If a postmining pollutional discharge
occurs, the discharger shall immediately provide interim treatment to comply
with the Group A effluent requirements in subsection (a), including
modifications authorized or required under subsection (e), (g) or (h). The
discharger shall also take whatever measures are necessary and available to
abate the discharge, including modifying the operation and reclamation plan for
the mining activity.
(2) If the
discharge continues to exist, after implementation of the abatement measures
required under paragraph (1), the discharger shall make provisions for sound
future treatment of the discharge to achieve the Group A effluent requirements
in subsection (c), including modifications authorized or required under
subsection (e) or (h). If the untreated discharge can be adequately treated
using a passive treatment system, in addition to achieving the effluent
requirements, the passive treatment system shall be designed and constructed to
accomplish the following:
(i) Prevent
discharge of mine drainage into the groundwater.
(ii) Prevent extraneous sources of
groundwater and surface water runoff from entering the treatment
system.
(iii) Hydraulically handle
the highest average monthly flow rate which occurs during a 12-month
period.
(iv) Have inlet and outlet
structures which will allow for flow measurement and water sampling.
(v) Prevent to the maximum extent practicable
physical damage, and associated loss of effectiveness, due to wildlife and
vandalism.
(vi) Be of a capacity so
that it will operate effectively and achieve the required effluent quality for
15 to 25 years before needing to be replaced.
(3) Any passive treatment system shall be
designed by, and constructed under the supervision of, a qualified professional
knowledgeable in the subject of passive treatment of mine drainage.
(g)
Single facilities for
sediment and erosion control. If a single facility is used for
sediment and erosion control facilities and treatment facilities covered by
this section, the concentration of each pollutant in the combined discharge may
not exceed the most stringent limitations for that pollutant applicable to a
component waste stream of the discharge.
(h)
Additional requirements.
In addition to the requirements of subsections (c)-(g), the discharge of water
from the permit area shall comply with this title, including Chapters 91-93,
95, 96, 97 (reserved) and 102.
(i)
Responsibility. The permittee is permanently responsible for
discharges which are encountered or are affected by or connected with the
mining or reclamation activities.
(j)
Exemption. The
Department may grant an exemption to subsection (b) only if the person who
conducts the operation demonstrates, and the Department finds, in writing,
that:
(1) Sedimentation ponds or treatment
facilities are not needed to achieve the effluent limitations in subsections
(c)-(f) and the water quality standards in Chapter 93.
(2) There is no mixture of surface runoff
with drainage from underground mine workings.
(3) The disturbed area is small for drainage
from areas affected by surface facilities.