2009 Montana Mining - Montana Mining Association

identified direct impact to 2.11 acres of
wetlands from the open pit mine expansion
disturbance, and 0.53 acres of indirect
impact to downstream wetlands that
56 Montana Mining 2009
would result from rerouting 1,800 feet of
the Clancy Creek stream channel around
the open pit perimeter. More than twothirds
of the 2.63 acres of impacted wet-
View of Clancy Creek stream split between existing open meadow channel and reactivated
Aspen Forest channel.
Overview of Montana Tunnels mine and wetland mitigation sites.
land area was classified as scrub-shrub
and emergent wetlands, with the remaining
0.72 acres inventoried as forest wetland.
Wetland mitigation ratios were proposed
to the USACE based on construction
of replacement wetland that would be
functionally developed prior to disturbance
of existing wetlands. Scrub-shrub
and emergent wetlands were proposed at
a 1:1 replacement ratio and forest wetlands
at a 1.5:1 replacement ratio.
Montana Tunnels identified several wetland
mitigation sites for USACE and other
agencies to evaluate. One of Montana
Tunnels’ preferred locations for all wetland
replacement was an eight acre site in
the Clancy Creek valley, directly downstream
of the open pit mine expansion.
This location would also disturb two acres
of wetlands that would require additional
wetland mitigation within that footprint.
A second preferred location was on the