GEOLOGIC MAPPING
IN SUPPORT OF LAND-USE PLANNING
Central Mesabi Iron Range
MINNESOTA GEOLOGICAL SURVEY
Mark Jirsa and Gary Meyer
August 1, 2007
Funded in part by
The Environmental Trust Fund administered by the
Legislative Commission on Minnesota Resources (LCMR)
Project Partners:
Central Iron Range Initiative (CIRI),
Minnesota Department of Natural Resources,
and NortheastTechnical Services
RATIONALE
PROVIDE FRAMEWORK GEOLOGIC MAPS AND TECHNICAL DATA TO:

Assist planning and development.

Guide resource management.

Avoid flooding, slumping, and infrastructure
damage.

Preserve water quality.
ULTIMATELY answer the questions:
•How high will the waters rise?
•What lands can be developed?
1985
2004
Hill Annex State Park
REQUIRES UNDERSTANDING:
The water balance (Hydrology-DNR)
Water in = rain, runoff, groundwater flow
Water out = evaporation, groundwater flow, pumping
The geologic “container” (Geology-MGS)
Groundwater flow through sand and gravel / fractures in rock
SUMMARY OF MESABI PROJECTS
1999-2007
1) HYDROGEOLOGIC BASE MAPS OF THE WESTERN AND EASTERN MESABI RANGE
(LCMR) Bedrock Topography and Depth to Bedrock
-Completed 2001 (W) and 2005 (E)
*DNR DIVISION OF WATERS: Site-specific hydrologic study of the CANISTEO PIT COMPLEX
2) BEDROCK AND QUATERNARY GEOLOGIC MAPS OF ENTIRE RANGE
(MCC) Geologic maps and ancillary data; completed November 2005
3) CENTRAL IRON RANGE INITIATIVE (CIRI) PROJECT
(LCMR) Geologic maps and subsurface data (MGS)
*DNR DIVISION OF WATERS hydrologic study
-Completion: June, 2007
COLLABORATORS, COOPERATORS, AND FUNDERS
MGS Staff:
Mining and Fee Company Staff:
•Val Chandler
•Mike Orobona (Hibtac)
•Roger Johnson (GNIOP)
•Dale Setterholm
•Jeff Price (Keetac)
•Doug Halverson (NorthShore)
•Rich Lively
•Dan England (Eveleth Fee Office) •Al Strandlie and Ron Graber
•Emily Bauer
•David Meineke (Meriden)
(Cliffs)
•Bruce Bloomgren
•Peter Jongewaard (United)
•Frank Pezzutto, Bruce Kniivila,
•G.B. Morey
•John Arola (ISPAT)
Jerry Dombek (Minntac)
•Gary Meyer
DNR Staff:
•Lisa Dosch
•Erika Herr
•Bob Tipping
•John Adams
•Tim Wahl
•Dan Steinbrink
•Carrie Jennings
•James Selner
•Wade Reynolds
•Tim Pastika (mine databases)
•Lynn Swanson
•Dave Dahl (geophysics)
•Lori Robinson
NRRI Staff:
FUNDING:
•Legislative Commission on Minnesota Resources (LCMR)
•Julie Oreskovich
•Minerals Diversification program of the Minnesota Legislature,
•Larry Zanko
recommended by Minerals Coordinating Committee (MCC)
•Mark Severson
•U.S. Geological Survey EDMAP program
•Minnesota Geological Survey—State Special funding
Mining altered the topography of watersheds
WATER ISSUES
~2004 waterline
Pump at Scranton Mine,
HIBTAC, 2004
Canisteo Pit Complex, 1999
MAPPING the shape of
the BEDROCK SURFACE
(1999-2002)
2) Hand contouring
1) Compile database
3) Scan and digitize
1899 MAP OF HIBBING AREA
Inferred geologic
contact
Test Pits
*Paper on linen maps, scanned and digitized
Contrasts in land-surface topography,
infrastructure, and surface hydrology
1899
Useful for issues of
mine reclamation and
watershed restoration
1999
Keewatin
Taconite
Hibbing
Taconite
Modified from Lively, Morey, and Bauer, 2002; MGS M-118
CHANGE IN LAND SURFACE
TOPOGRAPHY
“Mounds”
+240 feet
1899-1999
Hibbing Area
“Mines”
0 feet
-340 feet
Lively and others, 2002 estimate ~45% of the 1899 map area was modified by mining
BEDROCK AND QUATERNARY GEOLOGIC MAPS
OF THE MESABI IRON RANGE 2003-2005
1) Quaternary (glacial sediments) Geologic Map
2) Bedrock Geologic Map
3) Mine-scale Hydrogeologic Data
(groundwater “connectivity”)
•Funded by the Minnesota Legislature
on recommendation of the Minerals
Coordinating Committee
•Published November, 2005
Dunka pit 2004
FIELD WORK 2003-2006 in most of 400 mines
GARY MEYER
(MGS)
Quaternary geology
WADE REYNOLDS
Graduate student
Quaternary geology
CARRIE JENNINGS
(MGS)
Quaternary studies
MARK JIRSA
(MGS)
Bedrock structure
and stratigraphy
BEDROCK GEOLOGIC MAP
M-163
Mark Jirsa, Val Chandler, and Richard Lively
Babbitt
Hibbing
Grand Rapids
Biwabik Iron Formation
(~2 billion years old)
BEDROCK TYPES
Granite and
greenstone
(~3 billion years old)
Hibbing
Duluth Complex
Gabbro
(~1 billion years old)
Thomson Formation
Jay Cooke State Park
(~2 billion years old)
QUATERNARY (glacial sediments) GEOLOGIC MAP
M-164
Carrie Jennings and Wade Reynolds
Babbitt
Hibbing
Grand Rapids
MAPPING QUATERNARY
GLACIAL MATERIALS
NorthShore Mine 2004
Greenland
Advancing lobes of ice
GLACIAL LAYERS
St. Louis sublobe till (red)
Rainy Lobe till (gray)
Sand and gravel
(variably rounded, sorted)
Formed as OUTWASH
from the ice
Photo source:
Carrie Jennings, MGS
Sand and gravel
(dome shape, poorly sorted)
Formed in
TUNNEL VALLEY
Photo source: Carrie Jennings, MGS
Layered sand
(rounded pebbles, graded beds)
Formed by streams
flowing into local lakes
Photo source: Carrie Jennings, MGS
Canisteo pit lake at Bovey
Ironworld pit lake
Ironworld pit lake
Blast deformation
HIBTAC
BEDROCK
Folds, faults,
and fractures
m173e Susquehanna
•Role as hydrologic conduits
•Understand deformation history
WR joints Chisholm Mine
GROUNDWATER
m008g Hill Annex
WR Canisteo
m365a LTV 6
m131b United S. pit
SUMMARY OF FIELD WORK
AND OTHER ACTIVITIES
Central Mesabi Iron Range 2006-2007
Mark Jirsa and Gary Meyer
Minnesota Geological Survey
University of Minnesota
Funded by the Environmental Trust Fund administered by the
Legislative Commission on Minnesota Resources (LCMR)
Project Partners: Central Iron Range Initiative (CIRI),
Minnesota Department of Natural Resources,
and NE Technical Services
CENTRAL IRON RANGE INITIATIVE (CIRI) PROJECT
LCMR 2006-2007
AREA:
Keewatin to Virginia---focus on Chisholm lakes area
COOPERATORS:
•DNR Waters, Lands and Minerals
•Minnesota Geological Survey
•NE Technical Services
•Architectural Resources Inc.
•Barr Engineering
•Natural Resources Research Institute
•Mining companies
HIBTAC
OBJECTIVES--ADDRESS FUTURE ECONOMIC DEVELOPMENT ISSUES:
•Plan present and future mine landscapes
•Create fish-friendly bathymetry
•Evaluate energy storage and production
•Address water resources issues
CENTRAL IRON RANGE
Focused study in the Chisholm lakes area
Chisholm Lakes
Area
Digital Elevation Model
Central Mesabi Iron Range
DNR, 1999
HYDROLOGY OF THE CHISHOLM LAKES AREA
Water level gauge
Twin City N. Mine
MINNESOTA DEPARTMENT OF NATURAL REOURCES
DIVISION OF WATERS
Erika Herr and John Adams
Erika Herr, DNR Waters
BATHYMETRY
(lake-bottom topography)
CHISHOLM LAKES AREA
Forster
Hartley-Burt
Grant
Fraser
Twin City
Sherman
MINE WASTE
Longyear Lake
(1486’)
SEDIMENTS
Underground mines
100 feet
HIBTAC
HIBTAC
Iron World
pit complex
Iron
World
Twin
City
Sherman
Fraser
Grant
HartleyBurt Forster
(1473’)
(1343’)
1 mile
Vertical exaggeration ~50 X
BEDROCK
MINNTAC
Chisholm Lakes
Area
HIBTAC
KEETAC
Sand and gravel-filled bedrock channels
DIGITAL BEDROCK
TOPOGRAPHY—Chisholm area
Iron World
Twin City
Fraser
Forster
Sherman
Grant
3-D DIGITAL MODELS
Land surface elevation and pit lake bathymetry
from Department of Natural Resources;
Air photo from U.S. Farm Services Administration
Imagery by Richard Lively, MGS
3-D MODEL OF CENTRAL IRON RANGE
•BEDROCK TOPOGRAPHY (color) from MGS and DNR Bathymetry
•LAND-SURFACE TOPOGRAPHY (fade-in, pale color overlay)
Click image to start movie
“TYPICAL”
QUATERNARY SECTION
RED CLAY TILL
St. Louis sublobe (sources from NW and S),
small percentage of rock clasts
~100 feet
MESABI TILL
Rainy lobe (NE source) bouldery till;
locally white, red, yellow, brown, or gray.
Yellow stain inferred to represent
paleo - water level. Commonly contains
thin sand lenses and layers
Gary Meyer
Localized older, variegated clay till,
sand and gravel
Twin City south mine, north shore 2005
MINNTAC
Red clay till
Sand and gravel
Gray “Mesabi” bouldery, sandy till
Minntac West Pit, 2006
South Agnew Mine, 2006
Thick, layered
Sand and gravel
DRILLING
•Funded by LCMR contract to DNR
•Drilled by TRAUT WELL COMPANY
•Materials logged by MGS
DRILLING
•Distribution of subsurface materials (sand vs. clay)
•Test material properties
•Understand hydrologic connections
•Evaluate and quantify hydrologic properties
Example of cross-section, based in part on drilling
EXAMPLE OF BEDROCK OBSERVATIONS AND INFERENCES
From the ALBANY MINE
HIBBING
HIBTAC-Albany Mine
Hibbing photo by David A. Witt, P.G., Aero-Environmental Consulting 2005
HIBTAC-Albany Mine
=Seeps
PHOTO
FAULT ZONE
South end, Albany Mine
“SUSQUEHANNA FALLS”
Hibtac-Hull Rust Mine
HIBBING TACONITE
Hull-Rust Mine
Albany Mine
Susquehanna Falls
seeps
HIBBING
Susquehanna Falls
Outflow beneath talus
feeds waterfall.
Algae growth implies
warmer water source;
possibly derived
from Albany mine
through bedrock
fracture system.
METEORIC (surface) WATER SOURCE:
Short residence time (if any) in “aquifer”
GROUND WATER SOURCE
Long residence time(?)
in aquifer;
may explain common mineral
coatings
FINAL PRODUCTS
Available as Minnesota Geological Survey Open-File Report #07-02:
“Bedrock and Quaternary geology of the Central Mesabi Iron Range, northeastern Minnesota”
by Mark A. Jirsa and Gary N. Meyer
Printable pdf maps (shown on the following slides)
1. Bedrock Geology map
All products in digital format only.
2A. Bedrock topography map
2B. Bedrock topography-Chisholm area
3. Depth to bedrock map
4A. Surficial geologic map
4B. Sand and gravel units (shows cross-section line)
5. Lineaments map
6. Geologic cross-section
7. Locations of field observations
Other digital files:
• Abstract and Readme documents
• Shapefiles of all covers incorporated into pdf maps
(above); station locations (correspond to photographs)
• Tables of textural analyses of representative Quaternary
materials
• Digital photographs (keyed to stations)
• This PowerPoint presentation
1. BEDROCK GEOLOGIC MAP
Shows distribution of bedrock geologic units
beneath unconsolidated sediments and exposed in
natural rock outcrops and mines.
2A. BEDROCK TOPOGRAPHIC MAP
Shows elevation of top of the bedrock surface
beneath unconsolidated materials; areas of
active and previous mining shown in pink.
White=high topography
Black=low
2B. BEDROCK TOPOGRAPHYCHISHOLM AREA
Shows detail of bedrock surface
in area of focused study.
CHISHOLM
White=high topography
Black=low
3. DEPTH TO BEDROCK MAP
Shows thicknesses of unconsolidated materials.
Bedrock outcrops shown in red and mining areas
shown in black represent zero thickness.
White=thick sediment cover
Black=thin
4A. SURFICIAL GEOLOGIC MAP
Shows surface distribution of unconsolidated glacial sediments.
White areas represent surface materials disturbed by mining.
4B. SAND AND GRAVEL UNITS
Shows distribution of known sand and gravel
units near-surface (green) and at depth (tan).
5. LINEAMENTS AND BEDROCK STRUCTURE
Shows orientation of faults, folds, joints, veins, diabase
dikes, bedding, and planar foliation in bedrock;
at map and outcrop scales.
6. GEOLOGIC CROSS-SECTION
Shows distribution of unconsolidated glacial and
man-made materials at and beneath the land surface.
W
E
Example of detail in a cross-section
Red clayey till
Waste dump
Elevation (ft.)
Tailings
Overburden dump
Tan, rocky and sandy till
Gray clayey till
Sand
BEDROCK
Note: “till” is a mixed sediment containing various proportions of rocks, sand, silt, and clay
35 MILE SECTION: Along a line from Nashwauk to Virginia
7. MAP OF FIELD OBSERVATION POINTS
Shows locations of observations, including material
descriptions, samples, measurements, and photographs.
Red points are primarily related to bedrock observations;
green to observations of unconsolidated materials.