1
24-096
Downstream Improvements on Upstream Dams:
An Owner’s Perspective of a Paradigm Shift
Christopher R. Winter
Cleveland-Cliffs, Inc., USA
ABSTRACT
Mining companies have sharpened their refocus on their
tailings management strategies in recent years. Mining
companies with tailings storage facilities that use the
upstream construction method have been challenged
to track the evolution of industry standards, assess risks,
revise design, and communicate design revisions with reg-
ulators. While many aspects of best practices and indus-
try standards have evolved in recent years as an attribute
of continual improvement, the controlling standard in
the design of many upstream dams is understanding the
foundational strengths of hydraulically deposited tailings.
Following best practices and industry standards, Hibbing
Taconite Company managed by Cleveland-Cliffs, began
the re-evaluation of foundation strengths underlying a
system of upstream dams at the company’s iron ore mine
tailings storage facility in northern Minnesota. Initial steps
in the re-evaluation require reanalysis of design parameters
and recommendations by the Engineer of Record to the
Owner, which was followed by a series of meetings with the
Technical Review Board to determine an initial path for-
ward. Once a path forward and preliminary design param-
eters were determined, the Owner engaged with the State
Dam Safety Engineer to discuss and seek approval of the
plan. With continuous regulatory engagement throughout
the process, further refinement of the design parameters
for the hydraulically-placed tailings foundations underly-
ing upstream dams began with field and lab geotechnical
investigations. Following a review of risk assessments and
trigger actions response plans, Hibbing Taconite revised its
tailings storage facility operating plans and budget for the
coming years. Based on the findings of the re-evaluation,
reanalysis, and refinement of parameters, a paradigm shift
was realized with the hydraulically placed tailings founda-
tion strengths underlying the upstream system of dams.
This paper explores the path that the Hibbing
Taconite Company followed to understand the para-
digm shift and construct downstream improvements. The
plan involved tailings re-characterization, dam design revi-
sions, operating plan reconciliation, budget revisions, wet-
land permitting, dam safety permit amendments, storm
water prevention plans, borrow materials studies, new con-
crete decant structures and the pursuit to recognize and be
consistent with industry standards.
INTRODUCTION
Cleveland-Cliffs, Inc. is the largest flat-rolled steel producer
in North America. Founded in 1847 as an iron mine oper-
ator, Cleveland-Cliffs, Inc. also is the largest producer of
iron ore pellets in North America. The Company is verti-
cally integrated from raw materials from its Minnesota and
Michigan mines, direct reduced iron, and ferrous scrap to
primary steelmaking and downstream finishing, stamp-
ing, tooling, and tubing. Cleveland Cliffs, Inc. is the larg-
est supplier of steel to the automotive industry in North
America and serves a diverse range of markets due to its
comprehensive offering of steel products. Cleveland Cliffs,
Inc. is headquartered in Cleveland, Ohio with mining,
steel and downstream manufacturing operations located
across the United States and in Canada (Cleveland-Cliffs,
Inc. 2023a). Cleveland-Cliffs, Inc. has a long history of
safely operating tailings storage facilities and in 2022, was
awarded the Midwest Regional Award in, and presented by
the Association of State Dam Safety Officials. Cleveland-
Cliffs, Inc. operates five tailings storage facilities, and has
implemented proactive and conservative steps have been
implemented to ensure the safety of these dams against
potential failures. Through regular and rigorous review of
the facilities, Cleveland-Cliffs, Inc. updated emergency
action plans, reinforced thousands of feet of dam embank-
ment and modified operations to reduce safety risks. Cliffs
developed positive working relationships with state dam
24-096
Downstream Improvements on Upstream Dams:
An Owner’s Perspective of a Paradigm Shift
Christopher R. Winter
Cleveland-Cliffs, Inc., USA
ABSTRACT
Mining companies have sharpened their refocus on their
tailings management strategies in recent years. Mining
companies with tailings storage facilities that use the
upstream construction method have been challenged
to track the evolution of industry standards, assess risks,
revise design, and communicate design revisions with reg-
ulators. While many aspects of best practices and indus-
try standards have evolved in recent years as an attribute
of continual improvement, the controlling standard in
the design of many upstream dams is understanding the
foundational strengths of hydraulically deposited tailings.
Following best practices and industry standards, Hibbing
Taconite Company managed by Cleveland-Cliffs, began
the re-evaluation of foundation strengths underlying a
system of upstream dams at the company’s iron ore mine
tailings storage facility in northern Minnesota. Initial steps
in the re-evaluation require reanalysis of design parameters
and recommendations by the Engineer of Record to the
Owner, which was followed by a series of meetings with the
Technical Review Board to determine an initial path for-
ward. Once a path forward and preliminary design param-
eters were determined, the Owner engaged with the State
Dam Safety Engineer to discuss and seek approval of the
plan. With continuous regulatory engagement throughout
the process, further refinement of the design parameters
for the hydraulically-placed tailings foundations underly-
ing upstream dams began with field and lab geotechnical
investigations. Following a review of risk assessments and
trigger actions response plans, Hibbing Taconite revised its
tailings storage facility operating plans and budget for the
coming years. Based on the findings of the re-evaluation,
reanalysis, and refinement of parameters, a paradigm shift
was realized with the hydraulically placed tailings founda-
tion strengths underlying the upstream system of dams.
This paper explores the path that the Hibbing
Taconite Company followed to understand the para-
digm shift and construct downstream improvements. The
plan involved tailings re-characterization, dam design revi-
sions, operating plan reconciliation, budget revisions, wet-
land permitting, dam safety permit amendments, storm
water prevention plans, borrow materials studies, new con-
crete decant structures and the pursuit to recognize and be
consistent with industry standards.
INTRODUCTION
Cleveland-Cliffs, Inc. is the largest flat-rolled steel producer
in North America. Founded in 1847 as an iron mine oper-
ator, Cleveland-Cliffs, Inc. also is the largest producer of
iron ore pellets in North America. The Company is verti-
cally integrated from raw materials from its Minnesota and
Michigan mines, direct reduced iron, and ferrous scrap to
primary steelmaking and downstream finishing, stamp-
ing, tooling, and tubing. Cleveland Cliffs, Inc. is the larg-
est supplier of steel to the automotive industry in North
America and serves a diverse range of markets due to its
comprehensive offering of steel products. Cleveland Cliffs,
Inc. is headquartered in Cleveland, Ohio with mining,
steel and downstream manufacturing operations located
across the United States and in Canada (Cleveland-Cliffs,
Inc. 2023a). Cleveland-Cliffs, Inc. has a long history of
safely operating tailings storage facilities and in 2022, was
awarded the Midwest Regional Award in, and presented by
the Association of State Dam Safety Officials. Cleveland-
Cliffs, Inc. operates five tailings storage facilities, and has
implemented proactive and conservative steps have been
implemented to ensure the safety of these dams against
potential failures. Through regular and rigorous review of
the facilities, Cleveland-Cliffs, Inc. updated emergency
action plans, reinforced thousands of feet of dam embank-
ment and modified operations to reduce safety risks. Cliffs
developed positive working relationships with state dam