HomeMy WebLinkAboutRS_Coal_Mine_Hazard_Report_v11
Coal Mine Hazard Report
Address: 10814 SE 173rd St. Renton
Report Date: 5/23/2016
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Dear Client,
As requested, we have conducted a review of known coal mine maps in the area of the
proposed residence. We have determined that the coal mine risk to the site is low, with maps
indicating that there are possible mine works in the area listed as ‘declassified’. Please note that
our review consisted of reviewing existing maps as these maps did not indicate a greater risk to
the site. Review of existing documents cannot rule out the presence of unmapped or unknown
risks to the site.
We trust the information provided is sufficient for your current needs. If you have any
questions please contact us.
Regards,
Cash M. Carr PE.
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Regarding: Coal Mine Hazard Report
Address: 10814 SE 173rd St, Renton
Introduction
This report presents the results of our study of coal mine documents in the vicinity of the
proposed residence. Our research indicates that areas of moderate to high coal mine hazard
severity are located to the North of the site with the site being located in the vicinity of
declassified mine works. Declassified coal mines are those where the risk of catastrophic
collapse is not significant and that hazard assessments have been undertaken and found to not
require special engineering or hazard mitigation as we will explain in more detail.
Investigation
A thorough investigation into the possibility of a coal mine hazard at 10814 SE 173rd St,
Renton has found that the site in question is a declassified hazard area. According to the King
County Critical Areas Ordinance User’s Manual.
“‘Declassified’ coal mine hazard areas are those areas where the risk of catastrophic collapse
is not significant and that the hazard assessment report has determined do not require any
special engineering or hazard mitigation. These areas typically include sites not underlain by
underground workings and sites underlain by underground workings that are in excess of 300
feet below the surface.”
Limitations
This report is intended to determine the risk factors associated with known coal mines in
the area. Review of existing documents cannot rule out the presence of unmapped or unknown
risks to the site.
Conclusions
We have determined that the coal mine risk to the site is low, with maps indicating that
there are possible mine works in the area listed as ‘declassified’. As such, the coal mine hazard is
not a medium or high coal mine hazard.
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Appendix
The following maps indicate the property in question in relation to known coal mines and
coal mine hazards within the city limits of Renton. In each case, the property does not overlap
any known or mapped hazards.
FIG. 1: 2014. “City of Renton Sensitive Areas” Accessed via Official Site of the City of
Renton.. Property location is denoted by black star.
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FIG. 2A
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FIG. 2B
FIG. 2A: Full map of Northwestern Improvement Company’s land holdings. FIG. 2B: Area of
interest; N23 E5. Property location is denoted by black star.
Baily Willis Maps and Other Sources. 1918. Scale 1:48,000. “Map Showing part of the
Northwestern Improvement Company’s Coal and Land holdings; King County Washington”
Accessed via WA DNR Geology Portal.
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FIG. 3: Scale 1:4800. “Geologic Structure Map of Renton Coal Mine, Renton Coal Company,
Renton, Wash.” Accessed via WA DNR Geology Portal. Property location is denoted by black
star.