AGGREGATE POTENTIAL:  For the purpose of this study, aggregate potential is defined as an assessment of the relative probability that an
aggregate deposit exists within a given area, with almost all emphasis placed upon geologic evidence, parameters, and interpretation at 
the reconnaissance level, rather than upon economic feasibility evaluation or other parameters.  This assessment does not imply that 
everywhere within a given map unit designated as "Potential Aggregate Resources" there exists economic aggregate deposits.  Rather, that
within such a map unit, geologic processes were active that could have created aggregate deposits at specific sites.  Geologic measurements 
of aggregate deposits remain constant, but economic criteria and environmental permitting vary across time and place.  Important site-specific
factors such as ownership, zoning, protected waters and wetlands, environmental permitting and impacts, distance to markets, royalties, and 
individual site characteristics, such as access, all contribute to the final "potential" of a specific parcel, however, these factors were not
included in this study.
POTENTIAL SAND AND GRAVEL RESOURCES:  Those geologic units that are inferred to contain moderately and highly 
desirable sand and gravel deposits.  These units exhibit the geologic characteristics that typically produce sand and gravel   
deposits.  Existing gravel pits and MN/DOT aggregate sources lying within these units indicate identified or known resources.    
The geologic units having potential for sand and gravel include terrace, alluvial, delta, beach, flood plain, outwash channel,  
and ice contact (esker and kame) features; these units typically contain sorted sand and gravel with little silt or clay.
POTENTIAL CRUSHED STONE RESOURCES:  Those bedrock formations that consist of moderately desirable limestone 
(dolomitic limestone) that is suitable for crushing.  These units are inferred to be relatively thick (>50 feet) with overburden 
thicknesses of less than 10 feet.  Quarries located within these units indicate identified or known resources.  These  
bedrock resources are typically exposed as large benches along the Minnesota River where alluvial processes have eroded  
away the overlying glacial material.  Thin sand and gravel deposits are commonly found overlying these units.
LIMITED POTENTIAL FOR AGGREGATE RESOURCES:  Those units that generally have less desirable, little, or no potential  
for aggregate resources.  These units exhibit geologic characteristics that are typically not consistent with significant aggregate 
deposits.  The geologic units having limited potential include lake plains, moraines, and small alluvial deposits; these units  
typically contain clay, silt, fine sand, unsorted sediments (till), or very thin layers of sand and gravel.  These units may  
include aggregate deposits that are too small to be mapped.


IDENTIFIED AGGREGATE RESOURCES:  Those areas where aggregate resources (sand, gravel, and/or crushed stone) have been or are 
currently being mined.  Pit and quarry locations have been gathered from several different sources, including topographic maps, aerial 
photographs, county records, county highway department maps, soil surveys, MN/DOT files, fieldwork, gravel operators, and other
miscellaneous sources.  The pits and quarries range in size from less than 1 acre to greater than 50 acres and may be active, inactive,
depleted, or reclaimed.  The aggregate quality of the pits varies.
Gravel Pits:  Locations were gathered from several sources.  Any given pit may be active, inactive, depleted, or reclaimed.

Gravel Pits - MN/DOT files:  Minnesota Department of Transportation's Aggregate Source Information System listing of 
aggregate sources.  Test hole logs, sieve, and quality test data are available.  Green symbols indicate test pits that meet 
MN/DOT aggregate specifications for deleterious materials for concrete and asphalt.
Quarries:  Limestone quarries from several sources.  Any given unit may be active, inactive, depleted, or reclaimed.



WETLANDS:  Wetland area.



WATER:  Lakes or rivers.

