Table Name

Field Name

Begin Column

Definition

Valid Values

Descriptions

carlpits.dbf

PIT_Q_ID

Number, 9,0

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

Aggregate pit unique ID

Source

Text, 30

See Below

Construction aggregate pit data source compiled from or observed (ex: topographic map- found on the topographic map). Where multiple records existed for a single gravel pit, data points were removed based on a constructed hierarchy of source information. The following sources of information are listed according to rank.

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. This was ranked highest because of associated quality and texture data.  Some locations were modified to better correlate to present gravel pit boundaries and on top of USGS 7.5 Minute Topographic Map symbols.

Air Photo

Gravel mines were also located and some attributes were interpreted with air photography. These pits were ranked last because they were remotely interpreted. 

Field Work

These pits were located while in the field. These pits were ranked third highest due to the fact they were directly observed for quality, texture, and locational accuracy.

Soil Survey

The records for these pits are from the Soil Survey Geographic Database (SSURGO) for Carlton County. The dataset was downloaded in January 2008 and is current as of November 2006. These pits were ranked fourth highest.

Topographic Map

These gravel pits are located from USGS 7.5 minute quadrangles. This was ranked second highest because of the widespread use of the maps. Where field checked, some of these pit types were changed from gravel to clay, borrow or sand pits to reflect the material excavated.

Type

Text, 30

See Below

The type of pit 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.

Clay Pit

Clay Pit contains homogenous clay material of a quality used for creating bricks.

Asis_numbr

Text, 8, 0

Ex:  09002, 09019,, 09115,

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 carldotqual.dbf for the pits that list the Source as  “ASIS”

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

The thickness of the deposit expressed in combination with a modifier. 

Thick_mod

Text, 1

Ex: +,-

Modifiers to express numeric approximations observed for deposit thickness:

+  greater than

-  to, as in 10-20

Thick_min

Number, 4

Ex: 5, 10, 15…-999

Gives the minimum value for thickness. 

(-999 is a null value)

Thick_max

Number, 4

Ex: 5, 10, 15…-999

Gives the maximum value for thickness. 

(-999 is a null value)

Overburden

Text, 15

Ex: +10, ~20, +25, 10, 25

Expresses overburden thickness by possibly using one or both the modifier and value. 

Ob_mod

Text, 1

Ex: ~, -, +

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

~  approximate

-  to, as in 10-20

+  greater than

Ob_min

Number, 4

Ex: 5, 10. 15…-999

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

Ob_max

Number, 4

Ex: 5, 10. 15…-999

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

Watertable

Text, 15

Ex: +10, ~20, +25, 10, 25

The depth of the water table expressed in combination with a modifier. 

Wattabmod

Text, 1

Ex: ~, -, +

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

~  approximate

-  to, as in 10-20

+  greater than

Wattabmin

Number, 4

Ex: 5, 10. 15…-999

Describes the minimum 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)

Wattabmax

Number, 4

Ex: 5, 10. 15…-999

Describes the maximum 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 was not immediately active when documented or may appear to have been inactive for some time.

Reclaimed

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

Partially Reclaimed

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

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. The status could be a combination of more than one use.

Active

Specifies that mine is an active aggregate producing mine.

Agriculture

Mine has been reclaimed into an agricultural use.

ATV Trail

Mine is being used as ATV recreation area.

Commercial

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

Grass

Mine has been re-vegetated with grass.

Inactive

Mine is not presently active at time of assessment.

Industrial

Mine has been reclaimed into a refinery, substation, highway or other industrial application.

Naturally Vegetated

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

Partially Vegetated

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

Pond

Mining was likely below the water table and created a pond.

Recreation area

Mine has been reclaimed into a public recreation area.

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 a storage area including a timber storage site or a mini storage facility.

Trees

Mine has been revegetated with trees and shrubs.

Wetland

Part or all of mine is covered by a wetland.

Dom_litho

Text, 30

See Below

Dominant lithology of the pit.

Superior Lobe/Des Moines Lobe

Intermixed sediments from the Superior Lobe glacier and the St. Louis Sublobe of the Des Moines Lobe glacier. Sand and gravel associated with the St. Louis Sublobe glacier can contain deleterious rocks (like shale, iron oxides, and soft limestones) that can degrade the quality of the deposit. Stratigraphically the St. Louis Sublobe is on top of Superior Lobe sediments.

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). 

Dom_text

Text, 35

See Below

The dominant texture of the pit.

Clay

Very fine-grained minerals which show plasticity depending on water content. Used in the construction of bricks in the Wrenshall area.

Could not observe

The texture of the pit was undetermined due to lack of access or exposure. In some cases proximal geologic evidence was used to make a textural determination.

Gravel with Sand

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

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 overall has more sand than gravel by percent weight and has an overall fine texture.

Till

Heterogeneous deposit possibly consisting of any combination of clay, silt, sand, gravel, cobbles, and boulders. Any granular material is within a clayey or silty matrix. 

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.