Geology Reference
In-Depth Information
SIDEBAR 4.4 KENTUCKY FIRE DESTROYS MINE MAPS
A fire on November 12, 1948, destroyed at least 30,000 mine maps at
the Kentucky State Department of Mines and Minerals. This facility was
housed in a University of Kentucky building, which also contained the
Botany Department and the Kentucky Geological Survey. The Mines and
Minerals Department lost, in addition to the maps, its reports, including
safety records, inspection reports and recommendations. Many of these
maps charted abandoned mines dating from 1884 to 1948. State geologic
maps escaped the fire because they were kept at the home of the state
geologist. The cost of damage was assessed at $200,000, but many of
the lost records were irreplaceable.
Mine maps are now stored at Kentucky's Mine Map Information
Center. This center has operated the Mine Map Repository for the
Kentucky Department of Mines and Minerals for the past 28 years. The
center currently houses 100,000 coal mine maps and 140,000 mine
records. Although a few of the maps destroyed in the 1948 fire have been
replaced, the majority of the maps in the repository date only from 1948.
SOURCE:
Courier-Journal
(Louisville), 1948;
Lexington Herald
Leader,
1948.
in a surface survey. The horizontal (x,y) location of each spad is referenced
to the mine coordinate system. The z component is defined by the bottom-of-
seam elevation, a critical component of mine surveying. Current surveying
practice is to establish bottom-of-seam elevations by a level survey (30 C.F.R. ยง
75.1200-1(k)). However, older mines sometimes used the top of the seam to
refer to mine elevations. Hence, caution should be used in evaluating elevations
on older maps.
The primary use of elevation data is to track the flow path and potential
total pressure (head) of water that may accumulate in the mine. The data can
also be used for vertical location of the active mine in the framework of
overlying and underlying seams, which may be actively mined or may contain
abandoned mines, and for identification of undulations in the mine floor that
frequently correlate with poor roof or floor conditions.
The thickness of the outcrop barrier is critical to the evaluation of blowout,
blow-in, or breakthrough potential (see Chapters
3
and
6
). Because the last cut
is typically left unbolted, the measurement must be made remotely from the
protective cover of supported mine roof. Remote measurement can be routinely
accomplished with laser or sonar equipment that indicates distance by the
reflection of light and sound waves, respectively. The mine engineer or land
surveyor should be responsible for the accuracy in documenting the extent of
the final cut. Under no circumstances should the
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