We needed
an experienced engineer with a strong mining background to assist us.
We hired Engineer Ray M. Henderson PE. Mr. Henderson
was a former head of Engineering for Consol Energy. His oversight was
mines in Northern West Virginia and Western Maryland. Though he
possessed intimate knowledge of this area's mining topography, his concern was the parking lot / drainage area at the rear of
113 and 109 Platinum Drive. However, on his initial
visit he mentioned building 109 Platinum Drive was built over a coal seam.
Mr.
Henderson put forth Two
Engineering Reports:
Road
Correction
A
video clip of the parking lot area at the rear of 113
Platinum Drive, during a rain shower.
All the drainage from the rear parking lot
areas of buildings 109 and 113 Platinum Drive and the
complete roof drainage of both buildings 109 and 113 Platinum Drive, were being funneled into
their property, directly underground; at this sunk area location.
An area that was directly above our red barn.
The rough
outline is the area of the slip on our property. It is below the
Developer's parking lot area, shown in the video above, but far above
the new
structure.
Bear in
mind; the area that the new building sits on was composed of
compactable fill that was brought in by large tandem dump truck from
two other Bridgeport residential developments. The cost of this aspect
of site preparation was around $15,000.
During
the excavation for the Horner Brothers designed drain system, the
excavator encountered a natural bench, (bedrock).
French Drain System
The
French drainage system was placed
directly on top of this bedrock, (the best possible circumstance for a
French drain).
The drain system stayed on top of the bedrock until it
veered on
the southern side of the barn area to get a proper drop level for the
drainage that traveled through the French drain.The
existence of the bedrock is the reason the slip area had a dipped look
to it, (as noted earlier, by HR Marsh), and the reason the barn was
not affected. The barn and the road exists over bedrock. The barn was built 38 years ago. The road existed long
before that.
An estimate, without core drilling, is the
bedrock depth back into the hill is at least 24', taking into account
the position of the barn.
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