IdaradoMineRemedia-on Uncompahgre River Watershed - - PowerPoint PPT Presentation

Idarado
Mine
Remedia-on

Uncompahgre River Watershed

Prepared
by
Camille
Price Colorado
Department
of Natural
Resources Colorado
Department
of
Public Health
and
Environment

Erosion
and
Sedimenta-on

Red
Mountain
Creek
Water
Quality




Sedimenta*on
&
Leaching





Precipita*on
of
Heavy
Metals

Tailings
Stabiliza-on

Tailings
Stabiliza-on

RMT
‐
2
Before RMT
2
‐
AKer

Tailings
Stabiliza-on

RMT
4
‐
Before RMT
4
‐
AKer

Hydrologic
Controls

Upland
Diversion
Ditches

Tailings
Performance
Objec-ves

• During
the
last
2
years
of
10
year
evalua-on
period:




‐
live
vegeta-ve
cover
on
top
surface
&
slopes
is
>
60%; 


‐
total
vegeta-ve
cover
on
top
is
>
80%;
on
slopes
> 70%

• RAP
Modifica-on
(October
2004)
allows
for
ac-ve





management
of

tailings,
including
fer-liza-on, 



irriga-on
and/or
mowing,
if

approved
by
the
State 



each
year.

The
10‐year
revegeta-on

evalua-on
period 



will
commence
following
cessa-on
of
ac-ve 



management

• Annual
Monitoring
has
met
Performance
Objec-ves

Water
Quality
Performance
Objec-ves

• Average
of
6
samples
collected
on
6
different
days
between




August
15
‐
October
15
only
when
flow
rate
is
1380
‐
1690
gpm 


(3.07
‐
3.77
cfs)

• 50%
reduc-on
in
Dissolved
Zinc,
i.e.,

<
1.5
ppm
• If
the
necessary
flow
rate
does
not
occur
on
a
sufficient





number
of
days

Aug
15
‐
Oct
15
of
any
year,
the
compliance 



determina-on
period
will
be
extended
un-l
either
compliance 



is
achieved
or
appropriate

flow
rates
are
present 



Aug
15
‐
Oct
15
in
at
least
2
years
such
that
2
compliance 



determina-ons
can
be
made

• Since
1993,
flow
rates
were
present
between
1380
‐
1690
gpm






in

2009
&
2010
;
Avg.
Diss.
Zinc
concentra-on
2.35
in
2010

Zinc at RMC-1

y = -1.1439x + 2.7821 R2 = 0.9066 y = -1.698x + 3.4554 R2 = 0.7537 0.5 1 1.5 2 2.5 3 3.5 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Log Flow, (cfs) Zinc (mg/l) Post Remediation CD Criteria Pre-Remediation Linear (Post Remediation) Linear (Pre-Remediation)

Con-ngency
Plan

• Idarado
will
submit
a
proposal
for
addi-onal
remedial
ac-vi-es
to





be
conducted
at
sources
of
significant

zinc
loading
to
RMC 




by
April
15,
2012

• The
State
will
approve
or
disapprove
Idarado’s
proposal
in

wri-ng 




within
120
days
aKer
submission.

• The
State
will
approve
the
proposal
if
the
addi-onal
remedial






ac-vi-es
specified
in
Idarado’s
proposal
have
a
reasonable 




poten-al
to
yield
further
reduc-ons
in
zinc
concentra-ons 




sufficient
to
meet
the
RMC
water
quality
Performance
Objec-ve

• If
Idarado’s
proposal
is
approved,
Idarado
will
implement
the






ac-vi-es
in
the
proposal
in
accordance
with
a
schedule
approved 




by
the
State

RMC
Compliance
Evalua-on
Methodology

• The
Compliance
Determina-on
flow
was
met
in
two
• ut
of
the
last
18
years
since
the
Consent
Decree
was

signed

• Idarado
and
the
State
have
been
working
to
determine

an
equivalent
method
to
measure
the
water
quality
in Red
Mountain
Creek
that
is
not
limited
by
the
flow rates
defined
in
the
RAP

• Using
pre‐remedia-on
data,
a
linear
regression
of
flow

vs.
concentra-on
was
calculated.

It
shows
that
at higher
flows,
zinc
concentra-ons
decrease.

The compliance
criteria
of
a
50%
reduc-on
in
dissolved
zinc was
also
calculated
as
50%
of
the
linear
regression
of flow
vs.
concentra-on
using
the
pre‐remedia-on
data

RMC
Compliance
Evalua-on
Methodology

The
State
and
Idarado
agreed
that
the
Red
Mountain
Creek Performance
Objec-ve
will
have
been
met
if
:

• 50%
of
samples
collected
once
a
week
from
August
15
to




October
31,
on
days
other
than
during
storm
events,
fall below 


the
compliance
criteria
line
on
a
graph

• 50%
of
the
samples
represents
the
median
result
of
the





11

weeks
sampled

Idarado Natural
Resource Damage
Fund

• Restore
• Rehabilitate
• Replace
• Acquire

Natural
Resources
Damaged as
a
Result
of
a
Release
of
a Hazardous
Substance… Uncompahgre
River Watershed:

$220,000