5
and field-testing efforts with over 18,000 data points from
geotechnical testing programs at the Hibbing Taconite
Tailings Facility. In fall 2021, the findings of the Engineer
of Record were accepted by the Technical Review Board
and to date at Hibbing Taconite Company Tailings Facility
construction of downstream improvements are planned to
last until 2025.
Regulatory Engagement
Cleveland-Cliffs, Inc. wanted to engage regulators regard-
ing the dam design re-evaluation in a timely and transpar-
ent manner to facilitate potential permit modifications.
Permitting the downstream improvements had three
facets as shown in Table 2 below. The WCA Wetland
Replacement Plan Application began with wetland delin-
eation mapping during summer 2019. Wetland delinea-
tions were submitted to the Minnesota Department of
Natural Resources (MDNR). MDNR followed-up with a
field visit in September of 2019 with approval of the wet-
land delineation boundaries on January 2, 2020. During
that process Hibbing Taconite worked on the WCA
Wetland Replacement Plan. A pre-application meeting
was held with the regulatory agencies listed in Table 2 in
October 2019 with a follow-up call in November 2019.
The Wetland Permit Application was submitted in January
2020 and approved in August 2020, at which time the first
downstream improvement projects began immediately
after permit approval. Lessons learned on wetland replace-
ment plans include:
• Early engagement of agencies as the full process
turned out to take approximately 14 months.
• Final design construction limits should be submit-
ted with the wetland application to avoid dam design
creep.
• The construction limits that are set with the submit-
tal of the Wetland Application cannot be shifted with
further design revisions without resubmittal.
• Before commencing construction clearly mark the
construction limits and have a focused meeting with
the contractor regarding working around and pro-
tecting the construction limits.
Table 1. Hibbing Taconite Company Tailings Facility
Alternatives Analysis
Alternative Description
Alternative A Dam Design Revaluation Option
A—Ground Improvements of Fine
Tailings/Slimes Underlying the
offset upstream dam.
Alternative B Dam Design Revaluation Option
B—Upstream
Dam Construction
Alternative C Dam Design Revaluation
Option C—Downstream Dam
Improvements
Alternative D Modifications to Tailings Processing
Considerations—Filtered Tailings
(Dry Stacking)
Alternative E Do nothing option.
Figure 3. Hibbing Taconite Company Tailings Facility Alternatives Evaluation
and field-testing efforts with over 18,000 data points from
geotechnical testing programs at the Hibbing Taconite
Tailings Facility. In fall 2021, the findings of the Engineer
of Record were accepted by the Technical Review Board
and to date at Hibbing Taconite Company Tailings Facility
construction of downstream improvements are planned to
last until 2025.
Regulatory Engagement
Cleveland-Cliffs, Inc. wanted to engage regulators regard-
ing the dam design re-evaluation in a timely and transpar-
ent manner to facilitate potential permit modifications.
Permitting the downstream improvements had three
facets as shown in Table 2 below. The WCA Wetland
Replacement Plan Application began with wetland delin-
eation mapping during summer 2019. Wetland delinea-
tions were submitted to the Minnesota Department of
Natural Resources (MDNR). MDNR followed-up with a
field visit in September of 2019 with approval of the wet-
land delineation boundaries on January 2, 2020. During
that process Hibbing Taconite worked on the WCA
Wetland Replacement Plan. A pre-application meeting
was held with the regulatory agencies listed in Table 2 in
October 2019 with a follow-up call in November 2019.
The Wetland Permit Application was submitted in January
2020 and approved in August 2020, at which time the first
downstream improvement projects began immediately
after permit approval. Lessons learned on wetland replace-
ment plans include:
• Early engagement of agencies as the full process
turned out to take approximately 14 months.
• Final design construction limits should be submit-
ted with the wetland application to avoid dam design
creep.
• The construction limits that are set with the submit-
tal of the Wetland Application cannot be shifted with
further design revisions without resubmittal.
• Before commencing construction clearly mark the
construction limits and have a focused meeting with
the contractor regarding working around and pro-
tecting the construction limits.
Table 1. Hibbing Taconite Company Tailings Facility
Alternatives Analysis
Alternative Description
Alternative A Dam Design Revaluation Option
A—Ground Improvements of Fine
Tailings/Slimes Underlying the
offset upstream dam.
Alternative B Dam Design Revaluation Option
B—Upstream
Dam Construction
Alternative C Dam Design Revaluation
Option C—Downstream Dam
Improvements
Alternative D Modifications to Tailings Processing
Considerations—Filtered Tailings
(Dry Stacking)
Alternative E Do nothing option.
Figure 3. Hibbing Taconite Company Tailings Facility Alternatives Evaluation