Raven Cliff Furnace EarthCache
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From Speedwell Virginia, take Route 619 east. After seven
miles, you will reach the entrance to Raven Cliff campground. Turn
right onto the access road, the parking area is at the end of the
road on the left (see coordinates).
The trail begins in Raven Cliff campground and follows
Cripple Creek until ending at the remains of the old Raven Cliff
Iron Furnace. The trail is clearly marked with a sign. It is
very flat and an easy trip for the whole family.
The Furnace was built from sandstone than was cut
from the nearby Raven Cliff. This Cambrian to Ordivician period
sandstone is approximately 433 to 542 million years old and is part
of the Chilhowie Formation. While further south one may find
igneous rock in the Mount Rogers Formation, locally, sandstone is
by far the most common rock found. It's colors vary from near gray
to beige to maroon. Most of the sandstone of the Furnace is
very fine grained and extremely hard. Occasionally, a rare piece of
limestone is also found but it did not come from the immediate
area! Also, one may find some conglomerate rock in the area but
this too is rare but naturally occuring.
No more than 50 feet from the Furnace flows the
beautiful Cripple Creek. It flows beneath and beside the 200 foot
high sandstone, Raven Cliff. Cripple Creek also flows over
sandstone bedrock.
It is truly amazing to find a structure as old as the
Furnace and in such fine shape. The Raven Cliff Furnace was
built in 1810 and blasted nearby mined iron ore off and on until
being abandoned in 1893. The Furnace used hematite ore from a bank
four miles away. The other two ingredients necessary for the
production of the ‘pig’ iron were charcoal and limestone. Both were
in abundance in the local area.
The Furnace
Raven Cliff Furnace has gone through many name and
ownership changes. It was at various times called the Bell and
Kincannon Iron Works (1810-1857)), Wilkerson’s Furnace (1857-1861)
and the John W. Green Furnace (1861 - 1879) before receiving its
present name in 1879. Raven Cliff Furnace was first constructed
in1810 for Joseph Bell and Andrew Kincannon. The furnace continued
to produce pig iron during Reconstruction. It was again rebuilt in
1875 and sold to Crocket, Sanders & Co. The company changed its
name to Crocket & Co. three years later. The Furnace name was
changed back to Raven Cliff in 1879. Raven Cliff was
productive, and was in blast in the years 1880 through 1883. It was
transferred to Wythe & Speedwell Mining & iron
Manufacturing Co. in 1886. It changed hands many more times before
being abandoned in 1893 due to transportation difficulties, among
other problems.
Throughout its operation, the Raven Cliff Furnace
was cut off from easy routes of transportation. During the later
years of Raven Cliff’s operation, the Cripple Creek
extension of the Norfolk &Western Railroad had a spur line into
the site. This development, however, came too late in the life of
the Furnace to save it. Raven Cliff could not compete with
the extensive iron production of the Great Lakes Region.
The Raven Cliff Furnace is one of the oldest
structures of its kind standing today. Many other furnaces have
totally disappeared or have falling into rubble heaps. Maybe it is
a testament to the strength of Virginia’s sandstone? After all, it
has been around for a millions and millions of years!
The Structure
The square, trapezoidal stone Furnace is roughly 30 feet at
the base, tapering to 20 feet at the top. The overall Furnace
exterior is intact with clearly defined walls reaching 30 feet in
height. The cold-blast, charcoal stack ends with a 9’ bosh (top
opening).
With three tuyeres (openings which air is forced to
facilitate combustion as in blast furnace). The Furnace was
constructed of dry-laid, dressed local sandstone, with a
firebrick-lined chimney. “Dry-laid?, it cannot be stressed enough
as to exactly what that means. It means, no mortar, just extremely
well cut and well-fitted sandstone! The wider base with the
trapezoidal design plus the enduring quality of the sandstone is
why the Furnace stands today.
How the Furnace Worked
For the cold-blast process, the furnace was first filled
with charcoal and lit from the top. Over several days, the fire
burned down to the openings, and the furnace was refilled with
charcoal. Then the fire was allowed to burn back up to the top, and
a blast of cold air from the bellows brought the temperature up to
the ore-smelting temperature of 2300-2500 As the charcoal settled,
the furnace was continuously filled with layers of charcoal, ore,
and limestone. As the iron or and limestone melted, the limestone
served as a flux, cleaning impurities from the ore and forming
slag, which floated to the surface of the molten I During blast,
the furnaces operated day and night in 12-hour shifts for three or
four months, stopping only for maintenance and repairs. The iron
and slag were usually tapped twice daily. The molten iron flowed
into a casting bed made of sand A main trench (the sow) in the sand
allowed the iron to flow into numerous smaller side trenches (the
pigs), hence the name “pig iron.”
In one 24-hour period of operation, the Furnace
could consume an average of 750 bushels of charcoal, 12 tons of
iron ore, and many tons of limestone to produce five tons of iron.
To produce the 750 bushels of charcoal needed for 24 hours of blast
required 19 cords of wood, which means that about an acre of forest
was cleared for each day of furnace operation.
The Furnace was originally connected to the ridge to
the west by a charging bridge over which iron ore, limestone flux,
and charcoal were wheeled and dumped into the central, brick
cavity. A casting house where molten iron was formed into pigs by
the sand molding process was located east of the Furnace. A
waterwheel set north of and close to the stack powered the tub
bellows. A race ran the length of the foot of the hill to the creek
one-quarter mile away. Additional wooden structures were located on
the adjacent hill and originally included the iron master’s house,
workers' dwellings; general store, blacksmith shop, stables, and
iron ore and charcoal shed. The Furnace structures were rebuilt in
1861 and 1875. Sadly, these wooden structures could not stand the
test of time near as well as the Furnace.
One last geological note: If it were not for the geology of
the area there would have been no Furnace. It was the locally
available sandstone (to build it), limestone (to purify the ore)
and of course the iron ore itself (to be cast). This Furnace
and others like it played an extremely important role in the
America’s development.
Note: In order for you to claim a find you must
1. Post a photo of your group with GPSr in hand and the
Furnace in the background. 2A. How many layers are there in
the Furnace from bottom to top? B. Estimate the height of
the front opening, C. Estimate the overall height of the
Furnace, D. How many openings are there in the Furnace?
E. What type of rock was used to make the Furnace? (Yes, I
had to ask!)
Take a picnic, go back in time and enjoy! Be sure to find
Papafuz's very near traditional cache - GC1NYE7
This Earthcache was approved by the
Geological Society of America
| We have earned GSA's highest
level: |
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Additional Hints
(Decrypt)
Qba'g ohea lbhefrys!
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