1. TARGETED SOURCE CONTROL
What is needed are the new tools to identify contamination sources
within a mine so that the source control work can be targeted.
We believe that that a combination of isotopic, hydrometric, and
chemical characterization of water in and near mine-impacted regions can
identify contaminated and clean water WITHIN hardrock mines and
associated structures such as tailing piles.
Targeted source control techniques have the potential for tremendous
long-term cost savings relative to the prevalent end-of-pipe treatment
strategies.

2. TRACERS IN HYDROLOGY
HYDROLOGY
Of all the methods used to model hydrological processes in small watersheds, tracers (isotopic and chemical) have provided the best new insights into the age, origin, and pathway of water movement. The are among the few truly integrated measures of watershed function. Nevertheless, these techniques are not often used because the are seen as too complex, too costly, or too difficult to use.
MINE REMEDIATION
Tracers are under-utilized to even a much larger extent than in hydrology.

3. ISOTOPES IN HYDROLOGY What are environmental isotopes?
Environmental isotopes of an element are part of the natural environment. They are ideal for use as fingerprinting tracers since they are already present in the system they are not added to the environment.
Why would you use environmental isotopes?
The identification of fluid sources and pathways is often aided by the use of environmental isotopes. For example, waters from different areas may contain different isotopic fingerprints allowing the identification of the source.

4. ISOTOPE TABLE Isotope Symbol Molecule Type Half-life D H20 stable ---
Deuterium D
H20
stable
---
Oxygen- 18
18O
Stable
Tritium 3H
Radiogenic
12.7 years
Sulfur- 35
35S
SO42-
87 days
Nitrogen- 15
15N
NO3-

5. ISOTOPIC RATIOS , DELTAS, and PERMILS
Isotopic concentration are expressed as the difference the measured ratios of the sample and reference over the measured ratio of the reference. This is expressed using the delta (d) notation:
Since the differences in mass are generally small, delta values are often
expressed as parts per thousand or permil (‰):

6. CHALK CREEK MINE: GROUNDWATER SOURCE CONTROLS DEMONSTRATION PROJECT
EPA VIII 104(b)3 Program
SUPPLEMENTAL FUNDING REQUEST
Assistance Agreement MM

7. Objectives
[1] Use new procedures and techniques to refine the problem of identifying and isolating clean water inflows within the mine before they become contaminated by the orebody.
[2] Demonstrate that we can reduce the export of zinc by up to 85% using a source controls approach.
[3] Identify low-cost alternatives to remediation by preparing a detailed engineering evaluation an cost analysis (EECA) for a source controls program. The EECA will provide the foundation to test additional source control approaches at the Mary Murphy Mine proposed through the Hazardous Waste Center.
[4] Transfer technology on the methods developed from this proposal through reports to the EPA, peer-review papers, and personal contacts with state and reclamation professionals.

8. Chalk Creek Mine-Groundwater Source Controls Project Tasks & Milestones
Task Description
Cooperators
Fund Source
Time Frame
Run expanded scope Isotope tracer study of identified inflows and GW sources
INSTAAR/CDMG
Supplement to grant*
Through October 2001
Characterize inflow sources in upper levels of mine workings; sources of metals, metals loading analysis; refine hydrological model
CDMG/INSTAAR
Prepare a plan and “EECA” for a full-scale source controls remediation approach addressing up to 85% of metals pollution from the Mary Murphy Mine
CDMG/MES/CSM
Fall 2001, 2002
Transfer technology on the project methodology through tours, presentations, peer –review papers, and progress reports
CDMG/INSTAAR/EPA
HQ 104b3
Ongoing, finalize by 2002

9. 35S: APPLICATIONS FOR MINE REMEDIATION
1. ESTIMATE AGE OF WATER
Very effective for time scale less than one year
Few other environmental tracers can do this
2. DISCRIMINATE “NEW” vs. “OLD” WATER SOURCES
Particularly good for identifying snowmelt in mine discharge
3. DATE AGE OF SULFATE
Date age of atmospheric –deposited sulfate less than one year old
4. DISCRIMINATE ATMOSHPERIC FROM GEOCHEMICAL SOURCES OF SULFATE

10. Sulfur-35 (35S) IN THE ENVIRONMENT
Radioactive isotope of sulfate
Half-life of about 87 days
Produced by spallation of argon atoms in the atmosphere by cosmic rays
18Ar
N=22
16 S
N=16
Cosmic Rays O2
SO2
35SO42-
35SO42-
SO4-2

11. EVAPORATION USING WATER ISOTOPES
Calculated tritium output curve for the Grafendorf spring,
Massenberg Mountain, Austria. A similar approach can be
used to age water bodies inside the Mary Murphy Mine

12. 35S: UNITS AND VALUES Snowfall  60 mBq/L UNITS: Generally reported as
millebecquerels per Liter (mBq/L)
millebecquerels per mgSO4 (mBq/ mgSO4)
CONCENTRATIONS:
Snowfall  60 mBq/L
Snowmelt  20 mBq/L because of decay of snowpack
Rain(Summer)  100 mBq/L
FACTORS- extent of atmospheric mixing of stratospheric air into
troposphere; greatest in summer

13. 35S: Collection and Analysis
Sample Collection
Need 1-20 Liters of sample
pass sample through ion exchange resin in the field
elute SO42- from resin with barium chloride
final volume  100 ml
Sample Analysis
Liquid scintillation counting
Count twice, about 4 months apart as part of QA/QC

14. Year 2000: Comparison of sulfur and water isotopes at two internal streams within the Mary Murphy Mine The MVN3 stream has high zinc and the GTFI site has little zinc.
Isotope
GTFI
MVN-3
35S (mBq/L) 10
120
35S (mBq/ mgSO4)
0.3%
<0.1%
Atmospheric Sulfate
2.4%
18O (‰)
-16.2
-18.1
New Water (%) 3%
80%
The MVN stream was characterized by high amounts of 35S, a very low 35S to SO42- ratio, and relatively depleted 18O. These results suggest that the MVN stream is characterized by new water and that SO42- is from geochemical weathering. In contrast at the GTFI site, there is little new water and a low but much greater percentage of atmospheric SO42-.

15. HYPOTHESIZED ISOTOPES, MMM

16. SURFACE HYDROLOGY OF HARDROCK MINES
Hydrogeological settings:
Steep slops on mountainsides
thin soil
highly fractured bedrock
Water flow occurs primarily as fracture flow, reducing the effectiveness
of the classic porous medium approach for understanding hydraulic
connections within mine structures.
The subsurface hydrology is further complicated by the presence of
underground workings (adits, stopes, crosscuts, shafts, etc.), which perturb
the local and intermediate groundwater systems.
Relying only on monitoring wells and the assumptions associated with their
use often leads to an inadequate description of groundwater flow and
contaminant flux.

17. ISOTOPE COSTS Isotope Waterloo INSTAAR USGS D $39 $20 --- 18O $33 3H
$135
$100
35S
$200
15N18O3
$150

18. RECOMMENDATIONS FOR ADDITIONAL RESEARCH
Sample Analysis Reason
[1] all samples 18O and Zn
[2] 35S -separate ppt from groundwater
-700’ level
-other interior streams
-Chalk Creek
-methods development
[3] 3H -age groundwater streams
-interior streams
-Chalk Creek
[4] 15N18O3
- -source of NO3
-precipitation
[5] Discharge
-Hydrometric analysis
-interior streams
[6] Graduate Student -does the work

19. END OF PIPE STRATEGY

32. HYDROGRAPH SEPARATION

33. HYDROGRAPH AND ISOTOPES

34. ISOTOPES OF INTERIOR STREAMS

35. ZINC and HYDROGRAPH

37. SNOWMELT

38. BASEFLOW

39. END OF PIPE TREATMENT STRATEGY
Millions of dollars to install
Expensive to operate
Operate for long-term
Need low-cost alternatives

40. Mark Williams Jen Hazen Bob Michel INSTAAR, Stratus Engineering, USGS
ISOTOPE TRACERS AND GROUNDWATER FLOW FROM ABANDONED MINES IN A FRACTURED ROCK SETTING
Mark Williams
Jen Hazen
Bob Michel
INSTAAR, Stratus Engineering, USGS