Geochemical
Assessment of Subaqueous Tailings Disposal in Buttle Lake, British
Columbia 1993 Study Program
Mine Environment Neutral Drainage at CANMET-MMSL |
MEND Report 2.11.4a
May 1995
Executive
Summary
The dissolved
metal concentrations within Buttle Lake are among the lowest observed
in the last 20 years of observations despite continued inputs of
several trace metals (most notably Zn) from acid drainage in the
Myra Creek watershed. The tailings are restricted to the South Basin
and are now buried by several centimetres of oxic, natural sediments
admixed with a small component of tailings bioturbated upward from
below. The natural site indicates diffusive influxes of dissolved
Cd and Zn into the sediments while Cu and Pb show no indication
of reactivity. At both of the tailings sites, near surface pore
waters indicate remobilization of Cd, Cu, Pb and Zn (and Hg at the
distal site) likely associated with oxide dissolution. However,
the impact of the upward flux toward the water column is likely
attenuated by reprecipitation of Mn and Fe oxides which scavenge
trace metals. Arsenic distributions follow Mn and Fe cycling but
show no evidence of efflux. Simple flux-based diffusion calculations
suggest that effluxes of Cu, Pb and Zn to the South Basin bottom
waters are small and have limited impact on water quality; very
little, if any, oxidation of sulphide particles can be accommodated
by the near-surface pore water data. These observations are consistent
with those of previous studies of Buttle and other lakes.
A preamble
entitled, "An Overview of the Reactivity of Subaqueous Mine
Tailings Deposits" precedes the report to provide an appropriate
foundation upon which the data may be viewed.
Français
| Contact Us
| Help | Search
| Canada Site
Home | What's
New | CANMET-MMSL
| MMS Site
| NRCan Site
|