Pitl Lake Chararacterization Project, Phase II
This project involved an interdisciplinary research team which
studied Bioremediation of the Berkeley Pit Lake System; Water/Wall
Rock Interactions within the Berkeley Pit Lake; Organic Carbon in
the Berkeley Pit Lake Sediments; and Tailings Deposition into the
Berkeley Pit.
ALGAL BIOREMEDIATION OF THE BERKELEY PIT LAKE SYSTEM
Principal Investigator: Dr. Grant Mitman
gmitman@mtech.edu
It is know that if heterotrophic and autotrophic organisms are properly
nutrified, bioremediation of mine waste impacted areas can occur
as a result of the organisms’ biological processes. This knowledge
was the basis of bioremediation studies of indigenous Berkeley Pit
organisms. Under optimum conditions in a laboratory setting, it
was found that algae found in Berkeley Pit water were capable of
reducing dissolved metals concentrations in Berkeley Pit water.
WATER-ROCK INTERACTIONS AND ACCELERATED WEATHERING OF GEOLOGICAL
MATERIALS IN THE BERKELEY AND EAST CONTINENTAL PITS
Principal Investigator: Dr. Chris Gammons
cgammons@mtech.edu
An in-depth understanding of the pit wall mineralogy is vital to
understanding the wall rock interactions of the Berkeley Pit lake.
A suite of samples was collected from the north high wall of the
Berkeley Pit, with an emphasis on material which contained abundant
secondary minerals. A second suite of samples was collected from
the Lexington tunnel, a nearby underground mine tunnel. The sample
sets were then characterized by scanning electron microscope/energy
dispersive spectrometer (SEM/EDS) and x-ray diffraction (XRD).
ORGANIC CARBON IN BERKELEY PIT SEDIMENTS
Principal Investigator: Dr. Doug Cameron
dcameron@mtech.edu
The dissolved organic carbon concentration of the Berkeley Pit lake
was previously found to be between 2 and 3 mg nonpurgable organic
carbon per liter (NPOG/L), which is similar to the NPOG/L concentration
of the inflow surface waters. It was proposed that the organic material
within the pit lake is typical of alpine ground and surface waters,
and the majority of the NPOG is humic material. The significance
of this theory is that humic material plays an important chemical
role in aquatic ecosystems. However, this studied strongly suggested
that the NPOG present in the Berkeley Pit lake originates from well
and mine shafts waters which flow to the pit.
TAILINGS DEPOSITION INTO BERKELEY PIT LAKE
Principal Investigator: Dr. Courtney Young
cyoung@mtech.edu
The final area of study for this interdisciplinary project was to
assess the impact to the Berkeley Pit if tailings from an adjacent
mining operation were deposited into the pit, rather than pumped
uphill to a tailings pond. The tailings slurry produced from the
mining operation is high pH, while Berkeley Pit water has a pH of
approximately 2.5. The project studied the impacts to water quality
from a 1:1 tailing deposition, the long-term stability of the tailings/water
mixture, and the long-term stability of the tailings alone. On a
bench-scale, the tailings deposition was found to raise the pH from
2.5 to 6.5 initially, but pH dropped to 4.5 after 48 hours. Some
dissolved metals concentrations were lowered with the addition of
the tailings slurry.
Activity IV, Project 11
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