Fw: Virginian in 1907 -- Tunnel

[NW Mailing List]

Since posting my message below, I have been intrigued by the shaft that was dug midway of the Virginian's Allegheny tunnel so that digging could proceed both ways from the center as well as proceeding at both ends.  A Virginian track chart reveals that the depth of the tunnel at about midpoint is close to 100 feet below the surface of the ground at that point.  This shaft would had to have been equipped with some means of lowering men and tools and raising the excavated material.

When the shaft was no longer needed, was it just capped or was it backfilled with the excavated material?  If the latter, what care was needed to prevent rocks in the backfill material from damaging the tunnel roof after falling 100 feet.  Maybe the answer was to only backfill with rock-free dirt, although a supply of dirt might have been scarce because the lower part of the shaft and the tunnel probably went through mostly rock.  Anyone know what would be typically done with a disused shaft like this?

Gordon Hamilton

----- Original Message ----- 
From: Gordon Hamilton 
To: 2VGN Ry Yahoo Group ; N&W Mailing 2List 
Sent: Friday, June 06, 2008 10:25 PM
Subject: Virginian in 1907 -- Tunnel


Complete Allegheny Tunnel Early Next Year
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Meeting Occurred Last Week of Forces Cutting the Two Eastern Headings.
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FIVE THOUSAND FEET LONG AND TIMBER LINED THROUGHOUT
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    The meeting occurred last week, 1,645 [blurred; best interpretation shown] feet from the east portal and 1,220 feet from the shaft, of the two eastern headings of the Allegheny summit tunnel of the Virginian railway, near Christiansburg, marking the practical completion of the arch or heading.
    The tunnel has been worked both ends and both ways, from a shaft near the centre [sic].  On February 23, 1906, excavations from the tunnel proper was begun at the east end; late in April, 1906, from the shaft and west end.  On May 4th, of this year, the west headings came together.  In both ends of the tunnel now steam shovels are at work excavating the lower rectangular portion, or bench, east and west from the shaft.  Forces will soon begin to remove the "bench."  MacArthur Bros. Co. expect to complete the tunnel early in 1908.
    The tunnel is 5,140 feet long and lined with timber throughout.  A variety of rock is penetrated by the tunnel, from a hard brown shale and sandstone at the west end, to a soft decomposed limestone east of the shaft; ledges of hard limestone have been encountered also.  Throughout nearly the entire course, great inconvenience has been caused the forces at work, by the rush of water; five powerful pumps have been required to keep the heading faces free enough from water, in order to work them.  The grade slopes from the west end downward to the east, the summit being at the west portal.  The tunnel is so well graded that when completed it will drain all of the water out of its east end.  Great care has been taken in the instrumental work of aligning and leveling; measuring has been done with much care and repeatedly checked, but the result has fully repaid the trouble.
    East of the shaft the variations, as determined by checking, after breaking through, were just one-hundredth of a foot in elevation, and fourteenth-hundredths in measurement.  The superintendent in charge of construction is Mr. Pat Ford.  The resident engineer is Mr. D. E. Hall.

Bluefield Daily Telegraph
July 30, 1907

[The tunnel today has concrete lining and facades.]

Gordon Hamilton
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