Interpreting a Mine Summary Sheet
The mine summary sheet is arranged numerically by mine index number. Index numbers
are shown on the map and in the mine listing. The mine summary sheet provides
the following information (if available):
- Type: Underground denotes a subsurface mine
in which the coal was reached through a shaft, slope,
or drift entry. Surface denotes a surface or strip mine.
- Total mined-out acreage shown: Total acreage of the mined area mapped,
including any acreage mined on adjacent quadrangles. The acreage is calculated
from the digitized outline of the mine. The acreage of large barrier pillars
depicted on the map is excluded from the mined-out acreage. Small pillars
not digitized are included in the acreage calculation. If the mine outline
is not based on a final mine map, the acreage is followed by an estimate of
additional acres that may have been mined. The estimate is determined from
reported mine production, approximate thickness of the coal, and recovery
rates calculated from nearby mines that used similar mining methods.
- Shaft, slope, drift, or tipple locations: Locations of all known
former entry points (Shafts, slopes, or drifts) to underground mines or the
location of coal cleaning and shipping equipment used by surface mines (the
tipple). The location is described in terms of township (Twp), section, and
approximate footage from the section lines (EL = east line, NL = north line).
Entry points are also plotted on the map and designated on the summary sheet
as main shaft or air shaft on the basis of notations on the source map or
other data. A mine opening may have had many purposes during the life of the
mine. The tipple for underground mines was generally located near the main
shaft or slope. At surface mines, coal was sometimes hauled to a central tipple
several miles from the mine pit.
- Seam(s) mined: The name of the coal seam(s)
mined is listed if known. If multiple seams were mined, they are all listed,
although the mined-out area for each seam may be shown on separate maps.
- Depth: The depth to the top of the seam in the vicinity of the shaft
is listed if known. The depth is determined from notes made by geologists
who visited the mine during its operation or from drill hole data is ISGS
files. Depth generally varies little over the extent of the mine.
- Thickness: If known, the approximate thickness of the mined seam.
Thickness is also determined from notes of geologists who visited the mine
during its operation or from borehole data in ISGS files. Minimum, maximum,
and average thicknesses are given when this information is available.
- Mining method: The principal mining method
used at the mine
- Geologic problems reported: Any geologic problems, such as faults,
water seepage, floor heaving, and unstable roof, encountered in the mine This
information is from notes made by
ISGS geologists who visited the mine or from reports by mine inspectors
published by the Illinois Office of Mines and Minerals. Geologic problems
are not reported for active mines.
- Production history: Tons of coal produced from the mine by each mine
owner. When the source map used for the mine
outline is not a final mine map, the tonnage produced since the date of
the map is identified. For mines that extend into adjacent quadrangles, the
tonnage reported includes areas mined in adjacent quadrangles.
- Source map: Information about the map(s) used to compile the mine
outline and the locations of tipples and mine openings.
In some cases more than one source map was used. For example, a map drawn
before the mine closed may provide better information on original areas of
the mine than a later map. When more than one map was used, the comment section
explains what information was taken from each source.
- Date: Date of the most recent mine survey listed on the source map.
- Original Scale: Original scale of the source map. Many maps are photo-reductions
and are no longer at their original scale. The original scale gives some indication
of the level of detail of the mine outline and the accuracy of the mine boundary
relative to surface features. Generally, the larger the scale, the greater
the accuracy and detail of the mine map. Mine outlines taken from source maps
at scales smaller than 1:24,000 may be highly generalized and are probably
not accurately located with respect to surface features.
- Digitized scale: Scale of the digitized map. The scale may be different
from that of the original source map. In many cases the digitized map was
made from a photo-reduction of the original source map, or the source map
was not in a condition suitable for digitizing and the mine boundaries were
transferred to another base map.
- Map type: Source maps are classified into five categories to indicate
the probable completeness of the map. See discussion of source maps in the
- Annotated bibliography: Sources that provide information about the
mine. Some commonly used sources are described in the
Illinois Mining Bibliography.
Land Reclamation Division