Table Name

Field Name

Begin Column

Definition

Valid Values

Descriptions

millpits.shp

 

 

 

 

 

 

Pit_q_id

 

Number, 6,0

Ex:  1,2,3,4,5,6,7.... 341, 342, 343, 344

Aggregate pit unique ID

 

Source

 

Text, 16

See Below

Construction aggregate pit data source compiled from or observed (ex: topographic map- found on the topographic map).

 

 

 

 

ASIS

Minnesota Department of Transportation database called Aggregate Source Information Systems.  If the location did intersect a gravel pit, the locations were interpreted off of existing gravel pit sheets to relocate the mines to as specified on the sheet.

 

 

 

 

Air Photograph

Gravel mines were also located and some attributes were interpreted with air photography.

 

 

 

 

Fieldwork

These pits were located while in the field.

 

 

 

 

Topographic Map

These gravel pits are located from USGS 7.5 minute quadrangles.

 

Type

 

Text, 16

See Below

The type of pit or quarry observed

 

 

 

 

Gravel Pit

Gravel Pit

 

 

 

 

Sand Pit

Sand Pit

 

 

 

 

Borrow Pit

Borrow Pit- is defined not by use but by material.  If a pit contains significant clay and silt material, it was classified as borrow.

 

 

 

 

Quarry

Quarry (Construction Aggregate or Dimension Stone, See field ‘Status_2’ for quarry type)

 

Asis_numbr

 

Number, 9,0

Ex:  0, 47035, 47036, 47070, -999

Aggregate Source Information System Number (MN/DOT Database).  An empty field means that it does not have an ASIS number. Use this field to join with milldotqual.dbf for the pits that list the Source as  “ASIS”.  (-999 value is null)

 

Size

 

Text, 8

See Below

Refers to the relative size of the pit. 

 

 

 

 

Small

Small pits are generally less than five acres.  These pits are usually used by private landowners or for small jobs.

 

 

 

 

Medium

Between 5 and 15 acres in size.  These pits are used by landowners and for small construction jobs, They are generally used for short periods of time by contractors.

 

 

 

 

Large

These pits are generally greater than 15 acres and are typically used by commercial aggregate operators.

 

Thickness

 

Text, 15

Ex: >10, ~20, >25, 10, 25, <20, NA

The thickness of the deposit expressed in combination with a modifier.  ‘NA’ indicates not available

 

Thick_mod

 

Text, 1

Ex: ~, >, <

Modifiers to express numeric approximations observed for deposit thickness:

~ approximate

< less than

> greater than.

 

Thick_val

 

Number, 4

Ex: 5, 10. 15…-999

Gives a value for thickness. 

(-999 is a null value)

 

Overburden

 

Text, 15

Ex: >10, ~20, >25, 10, 25, <20, NA

Expresses overburden thickness by possibly using one or both the modifier and value.  ‘NA’ indicates not available

 

Ob_mod

 

Text, 1

Ex: ~, >, <

Modifiers to express numeric approximations for the overburden thickness at a gravel pit

 ~  approximate

<  less than

 > greater than

 

Ob_val

 

Number, 4

Ex: 5, 10. 15…-999

Gives a value for overburden thickness.      (-999 is a null value)

 

Watertable

 

Text, 15

Ex: >10, ~20, >25, 10, 25, <20, NA

The depth of the water table expressed in combination with a modifier.  ‘NA’ indicates not available

 

Wattab_mod

 

Text, 1

Ex: ~, >, <

Modifiers to express numeric approximations for the depth to the water table:

~  approximate

<  less than

 > greater than

 

Wattab_val

 

Number, 4

Ex: 5, 10. 15…-999

Describes the depth to the water table within a pit or quarry.  If 20 feet of gravel was exposed and there was no water table encountered, then >20 were used.

 (-999 is a null value)

 

Status_1

 

Text, 20

See Below

Refers to the status of the pit at the time of mapping. 

 

 

 

 

Active

Active indicates that the pit is either being actively mined or used for other mining related usage like stockpiling material.

 

 

 

 

Inactive

Refers to a pit that does not appear to have been active for some time.

 

 

 

 

NA

Not available

 

 

 

 

Prospective Pit

Mine that has MN/DOT data but has not been developed.

 

 

 

 

Reclaimed

The pit has been passively or actively reclaimed. Status_2 further describes type of reclamation

 

 

 

 

Vegetated

Part or all of mine that has been re-vegetated.

 

Status_2

 

Text, 50

See Below

Associated with the field Status_1.  This field further explains the condition of a partially or fully reclaimed gravel pit.  Additionally, it explains the type of active quarry, such as an aggregate or dimension stone quarry.

 

 

 

 

Aggregate

Specifies that mine is an active aggregate producing mine.

 

 

 

 

Agriculture

Mine has been reclaimed into an agricultural use.

 

 

 

 

Commercial Development

Mine has been reclaimed into an commercial development like a strip mall, a store, etc.

 

 

 

 

Dimension Stone Quarry

Mine is a quarry producing dimension stone (granite used for counter tops, gravestones, building facades).

 

 

 

 

Field

Mine has been reclaimed into a field.

 

 

 

 

Golf Course

Mine has been reclaimed into a golf course.

 

 

 

 

Graded

Mine has been actively reclaimed and mine walls have been sloped.

 

 

 

 

Grass

Mine has been passively reclaimed and re-vegetated with grass.

 

 

 

 

Grassland

Mine has been reclaimed into grassland.

 

 

 

 

Highway

Mine has been reclaimed or has been developed over by a highway.

 

 

 

 

Lake

Mine has been reclaimed into a lake or a body of water.

 

 

 

 

Meadow

Mine has been reclaimed into a meadow.

 

 

 

 

NA

Not Available

 

 

 

 

Naturally Vegetated

Mine has been passively, or naturally re-vegetated over time.

 

 

 

 

Parking Lot

Mine has been reclaimed into a parking lot.

 

 

 

 

Partially Vegetated

Mine has been partially re-vegetated and is partially unreclaimed.

 

 

 

 

Residential

Mine has been reclaimed into residential development.

 

 

 

 

Sloped

Part or all of mine has been actively reclaimed and mine walls have been sloped.

 

 

 

 

Storage

Mine has been reclaimed into commercial development- mini storage.

 

 

 

 

Transfer Station

Mine has been reclaimed into a transfer station.

 

 

 

 

Trees

Part or all of mine has been actively reclaimed by natural re-vegetation of trees.

 

 

 

 

Vegetated-Grass

Part or all of mine has been actively reclaimed by natural re-vegetation of grass.

 

 

 

 

Vegetated-Trees

Part or all of mine has been actively reclaimed by natural re-vegetation of trees.

 

 

 

 

Wetland

Part or all of mine is covered by a wetland.

 

 

 

 

Wetland and Grass

Part or all of mine is covered by a wetland and grass.

 

 

 

 

 

 

 

Dom_litho

 

Text, 30

See Below

Dominant lithology of the pit

 

 

 

 

Des Moines Lobe

Sand and gravel associated with a glacier called the Des Moines Lobe.  These sands and gravels contain deleterious rocks (like shale, iron oxides, and soft limestones) that can degrade the quality of the deposit.

 

 

 

 

Granite

An intrusive, felsic igneous rock that has a medium to coarse texture.

 

 

 

 

NA

The source of the sand and gravel could not be determined.  This is primarily due to the deposit could not be accessed and was not observed and the surrounding geology is too complex to extrapolate the source.

 

 

 

 

Quartz Monzonite

An intrusive igneous rock that has a specific composition of equal portions of orthoclase and plagioclase feldspars.

 

 

 

 

Rainy Lobe

Rainy Lobe is a northeastern sourced glacier flowing along the highlands of eastern Minnesota to the southwest.  Rainy Lobe sediments tend to contain high percentage of granites and granitic rock types.  Aggregate with Rainy Lobe rock lithologies generally are of high quality and durability.

 

 

 

 

Superior Lobe

Superior Lobe is a northeastern sourced glacier flowing from the Lake Superior basin to the southwest.  The quality of these deposits tends to be good to very good due to the rock types found within the deposits (basalt, granite, gabbro).  Also, these deposits have undergone some degree of mixing with rock types associated the Rainy Lobe (granites).

 

 

 

 

Superior/Rainy

Superior Lobe sediments stratigraphically above Rainy Lobe sediments.

 

Dom_text

 

Text, 35

See Below

The dominant texture of the pit

 

 

 

 

Gravel

Rock fragments of specific particle size that is larger than 2 mm and less than 63 mm.

 

 

 

 

Gravel and Till

Containing both gravel and till (unsorted sediment deposited by glaciers- contains a mixture of clay, silt, sand, gravel and boulders).

 

 

 

 

NA

The texture of the gravel pit was undetermined due to lack of exposure or geologic evidence to make a determination.

 

 

 

 

Sand

Indicates the deposit is composed of sand and has a fine texture.

 

 

 

 

Sand and Gravel

Indicates the deposit has approximately equal or slightly more sand than gravel by percent weight.

 

 

 

 

Sand minor Gravel

Indicates the deposit contains mostly sand with few gravel-sized rocks and has a fine texture.

 

 

 

 

Sand with Gravel

Indicates the deposit has more overall more sand than gravel by percent weight and has an overall fine texture

 

Comments

 

Text, 100

Ex:  Very sandy deposit with limited gravel

Geologist comments related to the pit

 

GPQNAME

 

Text, 50

 

If available, the pit name at the time of mapping