Allow me to clarify the sequence of events concerning the Falling
Creek Ironworks. What was uncovered by recent floods was the
culmination of a series of floods starting with Hurricane Fran,
Gaston and a few others. They successively peeled back the bank. Then
two minor storms that dumped about 5" of rain into the Falling Creek
drainage ate into the south bank just below the falls. That exposed a
set of massive timbers. Those timbers are seen as part of the
1621-1622 Falling Creek blast furnace building set.
Technological background:
Iron can be smelted (made) from ores by the direct method. A bloomery
makes iron in a structure resembling an overgrown brick 1950's style
backyard barbecue. What they get is a bloom of wrought iron that can
be whanged by a blacksmith into nails, hinges or whatever a
blacksmith wants to and can make. Output is small.
The indirect method is a blast furnace. These are giant square stone
chimneys that taper slightly as they rise. They may be up to 25'
square and up to 25' high. The ironmaster has 3 layers of material. A
layer of charcoal, a layer of iron ore and a layer of flux. If the
ore is self-fluxing, there is only the charcoal and the ore. The
furnace is fed by dumping the charge (charcoal, ore & flux) down into
the furnace from the top from the charging bridge. The furnace is
first put into blast by lighting charcoal that has partially filled
the interior. When it is suitably warm, the layering starts.
Blast furnaces are so named because they require a blast of air. This
comes from a set of bellows that resembles a standard fireplace
bellows, but several orders of magnitude larger. It is powered by a
water wheel. The water wheel is fed by a flume, or wooden trough that
carried water from the dam to the wheel.
Although Falling Creek was deemed a near perfect place for a furnace,
it was not ready built. The dam had to be built across the creek.
From evidence of post sockets cut into the granite on the two sets
of falls there, the dam was moved twice. The flume also appears to
have been moved. It also had to cross a large deep hole, and go
around a promontory and then empty onto the wheel.
The ironmaster will check the contents at the bottom of the furnace.
There are typically two arches built into the furnace. One carried
the bellows that feeds into a hollow tube called a tuyere that feeds
the air directly into the furnace bottom. The blast of air is what
makes it all work as a blast furnace. Within the furnace, there has
to be a reducing atmosphere. It is a common misperception that all
one has to do is heat ore and iron will drip out of it. If one heats
iron ore, all one ends up with is hot ore. There is a chemical
reaction where the FeO or FeO2 has the O and/or O2 combine with the
Carbon and the furnace vents carbon monoxide or carbon dioxide. Then
pure Fe can drip into the bottom of the furnace where it is
periodically drawn off through a small door in the second arch known
as the casting arch.
The result of a blast furnace smelting operation is an ingot of iron,
commonly called a pig. These are about 3 feet long and 4 inches
square and weigh up to 75lbs. They are called pigs because the iron
is run or tapped out into a large channel cut into sand on the
casting floor. From the large channel, the molten iron runs into
several smaller channels. Viewed from above, the large channel is
seen as a sow pig and the small channels are viewed as suckling pigs,
hence the name. A furnace of the early 17th century could produce up
to 600 tons of pig iron a year.
The pig iron is the sole product of a blast furnace. Just to
complicate the issue, it was sometimes a practice to run hot iron
directly into molds that produced pots, kettles, frying pans, etc.
More commonly, pig iron was shipped to two different types of
industrial plants for processing. A foundry produced cast iron
products by buying pig from a furnace and re-melting it and running
it into molds.
A forge, such as Archibald Cary's, bought pig iron from a furnace and
put it into a forge that refined it (finery forge). It was slowly fed
into a slag bath with the aim of decarburizing the iron farther. When
it was suitably done, the resultant iron mass was formed with a very
large water powered helve hammer (1200 lbs) into a bar-bell shaped
anchony. It was also further mashed into bar iron and rod iron that
was then sold to blacksmiths to make enduser products.
In the late 18th and into the 19th century, technological innovations
changed how iron was made and processed. But for the purposes of
discussion about the 17th and 18th century ironworking operations at
Falling Creek, the above described process was used.
Proof positive that a blast furnace got into operation was dense
glassy slag typically dark green or dark blue in color. This material
is glass and has been used by glassmakers who bought old furnace slag
piles. To date, not one piece of that has been found at Falling Creek.
The typical product of a forge is a bubbly slag with charcoal pieces,
iron lumps and other materials encased in a silica lump. At the end
of the day, each hearth at a forge was emptied. These items are
called skulls or mossers because they resemble a human skull. They
are discarded. The floodplain at Falling Creek is littered with these.
The typical product of a foundry is a denser, ropey or lava appearing
lump of slag. Both the foundry and the forge are huge producers of
waste products that are trodden into the ground around the operation
and are in fact hauled off to build up land from marshy areas.
A blast furnace, a foundry and a forge are vastly different
technologies. People will tend to use them interchangeably until they
are aware. However, to an industrial archaeologist, it is as if
someone confused a car with a plane with a boat and used the terms
interchangeably. They're all means of transportation but beyond that,
they are screamingly different. At Falling Creek, there was a blast
furnace in the early 17th century and a forge in the second half of
the 18th century. There was no foundry.
Background history:
The Virginia Company in 1619 sent a fellow named Blewitt with a crew
to set up a blast furnace as a money making venture. A small trial of
iron had taken place earlier that proved that iron could be made from
either the abundant bog ores in the James River basin or from iron
ores in rock formation. Blewitt died on the voyage over. It is
unknown what, if anything, the rest of the crew did. Then in 1621,
John Berkeley and his son Maurice with another crew were sent over to
build the blast furnace. They sent a letter back in 1621 that they
would have a plentiful supply of pig iron by Whitsuntide (May 14) of
1622. Unfortunately, the Powhatans staged a coup de main on March 22,
1622 that killed all but two children at the site. Maurice escaped as
he was elsewhere. There were 3 other attempts in the 17th century
with no known result. Then in 1750, Archibald Cary started a forge on
the property that continued to 1781 when it was burned by Benedict
Arnold.
It has been known from local stories where the furnace was located
generally. And, anyone with technical knowhow would also immediately
see where it had to be. Plus, the ground in the area was littered
with iron waste. Starting in the 1880's with Brock from the
Smithsonia, the site has been investigated. Each investigator
pronounced themselves certain that they had seen evidence of the
ironworks of 1619-1622. Roland Robbins who dug Saugus Ironworks in
Mass. also visited and was also impressed. A succession of folks in
the 1950's to the 1990's also visited and were certain they'd found
the location. The charcoal pile had been discovered on the south bank
and had been radiocarbon dated in the 1990's to the 1570's. The
topography fairly screamed out where the furnace had to be located.
The problem was that all of those who had come, looked, dug, and
pronounced with certainty that they had discovered the ironworks were
not technologically literate. What they had seen were pieces of pig
iron, slag, charcoal with slag, etc. All of that was part of the Cary
forge.
The Falling Creek Ironworks Foundation was formed to be a steward of
the site by a group of concerned citizens in Chesterfield County. Two
archaeologists with a background in industrial archaeology and
ironworking were part of the mix. Our job was to provide the
technical expertise for the planned excavation. Chesterfield County
had acquired the property as a park. Working with the county, the
Foundation started the process of planning the events. We knew where
the ironworks was located from several pathways. Roger Bensley, in
1937, had uncovered the casting floor apparently during roadbuilding
operations and had covered it back over. Due to the overburden of
Cary forge slag, flood deposits and the roadway, and in the main due
to the absence of furnace slag, the main question was whether the
furnace had gotten into blast prior to March 22, 1622. We then did a
geophysical survey of the property. Resistance survey showed what
appeared to be large buildings on the floodplain. They were
consistent with warehouses that Cary had that were burned by Arnold
in 1781. Magnetometer survey showed a massive magnetic anomaly
consistent with a blast furnace exactly where all and sundry had
thought it should be. The mag survey was the first indication that
the furnace had gotten into blast. When ground is heated above the
blocking temperature (565°C to 675°C), iron atoms in the area above
that temperature will align themselves with the earth's magnetic
field and when the area cools back down, the atoms are locked into
position. Compared with the random orientation of those surrounding
areas, the magnetometer detects a large change in the local magnetic
field. That massive anomaly proved that the Virginia Company had
fired the furnace. So, either the furnace actually got into
production for a short period or it was knocked out just as it got
into production by the Powhatans.
The Physical Remains
Several large timbers up to 32"x24"x10'+ were exposed. They appear to
form a cribwork which is a rectangular framework that is infilled
with stone and clay to make a stable foundation for whatever is to be
built on top. There is over 6' depth of cribwork there so it's
massive. It is also about 60 feet long stretching down the bank and
goes back into the bank for an unknown distance, but not more than 30
feet. One thing a blast furnace cannot have is water in it because it
will instantly turn to steam and explode. Thus the ground needs to be
prepared properly to hold up the furnace stack, to hold the bellows,
axle (treetrunk 2' diameter size) and the water wheel, plus the end
of the flume.
That appears to be what we have there. Stratified over the cribwork
is a set of flood deposits and about 3' above the top of the cribwork
is a 4" layer of Cary forge slag. There is absolutely none of that in
the timber crib fill. That is an excellent example of stratigraphic
separation of the presumed 17th century structure set from the
1750-1781 Cary forge operation.
The game plan is to excavate it to see what we do have, remove and
preserve the timbers and to put them on display in a museum at the
top of the hill. That will require fundraising and a lot of capital
to accomplish. We will be actively seeking funds to further the work
and to get the museum built.
Lyle Browning, RPA
Archaeologist
Falling Creek Ironworks Foundation
On Jan 20, 2007, at 8:03 PM, Sunshine49 wrote:
> An article and pictures in today's Richmond Times Dispatch said the
> timbers were part of the base for a flume that sent water through
> the forge to power it. Since I know nothing much about ironworking,
> I have no idea what that means [other than what a flume is]. It
> said the newspaper also now has a "multi media presentation" about
> the discovery, whatever that entails [multi media?]. http://
> www.timesdispatch.com
>
> Nancy
>
> -------
> I was never lost, but I was bewildered once for three days.
>
> --Daniel Boone
>
>
>
> On Jan 19, 2007, at 11:42 PM, James Brothers wrote:
>
>> Ironmasters will meet this year in conjunction with the
>>
>> 37TH ANNUAL MEETING OF THE MIDDLE ATLANTIC ARCHAEOLOGICAL CONFERENCE
>> March 15th-18th, 2007
>>
>> Cavalier Hotel
>>
>> Oceanfront at 42nd Street
>>
>> Virginia Beach, Virginia 23451
>>
>> Reservations: 1-800-446-8199
>>
>> or on-line: www.cavalierhotel.com
>>
>> Ironmasters is a group of archaeologists, historians, and just
>> people interested in the history of iron making. This years
>> meeting will feature a bloomery smelt at Colonial Williamsburg
>> (Saturday) and papers on early iron making. The following papers
>> are already scheduled. But there is room for a few more. If you
>> are interested please contact me.
>>
>> Lyle Browning (Browning and Assoc, Ltd.)- Latest information from
>> America's first ironworks, Falling Creek (1619-22). Just recently
>> massive timbers have appeared as a result of erosion of the bank.
>> These are 2-3' below Archibald Cary's Forge (1750-81). It is
>> unclear at this time whether these are part of the ironwork's
>> warf, dam, or actual structure. But excavation on the site should
>> be underway prior to the conference.
>>
>> Richard Veit (Monmouth Univ,) and Michael J. Gall (Richard Grubb
>> and Associates)- Two late 18th century bloomeries in New Jersey,
>> Leddell/Frost Forge in Bernardsville and the Mendham Forge in
>> Mendham, Morris County. Both date from the late 18th century.
>>
>> I will be giving a talk updating some of the information on the
>> colonial blast furnaces of Virginia.
>>
>> James Brothers, RPA
>> [log in to unmask]
>>
>> To subscribe, change options, or unsubscribe, please see the
>> instructions
>> at http://listlva.lib.va.us/archives/va-hist.html
>
> To subscribe, change options, or unsubscribe, please see the
> instructions
> at http://listlva.lib.va.us/archives/va-hist.html
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