This is an Earthcache and as such logging it
requires special tasks be undertaken. Failure to complete the
assigned tasks may result in the deletion of your log.
The park is open daily from 6:00am to 10:00pm. Pets are not
allowed.
Lime Kiln Park
Wisconsin's early lime industry
Years before Wisconsin became a state the early settlers were
mining and firing limestone to create quick-lime for use as mortar
and whitewash. In the 1850's the commercial production of lime was
concentrated mainly in the eastern counties where some of the
state's most abundant limestone deposits were located. By the late
1800's Wisconsin had become one of the countries leading lime
producers shipping over one million barrels annually.
As transportation methods improved commercial lime production
began to spread to other counties of the state especially Fond du
Lac, Door and Manitowoc. Competition, hardwood shortages, increased
transportation costs and the growing use of Portland cement made
small-scale kilns become increasingly unprofitable and many ceased
production by the early to mid 1900s. The final nail in the coffin
for many kilns was the beginning of the Great Depression which saw
a near standstill in the construction industry.
Brief history of the kilns at this site
In the mid to late 1800's lime kilns began to be built locally to
process the areas easily mined limestone. Lime Kiln Park in Grafton
was once part of a limestone quarry operated by the Milwaukee Falls
Lime Company which was incorporated in 1890. Originally there were
five cordwood-fired kilns at this site though only three have been
restored. These kilns stopped production in the 1920's.
The firing process
Simplified, a lime kiln is an oven used to produce quicklime by the
"calcination" of limestone. Limestone is made up mainly of three
components: calcium, carbon and oxygen. When limestone is heated
the carbon escapes as carbon dioxide, leaving lime. This reaction
takes place at 750°F, but a temperature up to 2,000°F is usually
used to make the reaction proceed more quickly. The process of lime
burning was carried out by a kilnsman who was experienced in the
reduction of limestone. An experienced kilnsman was required to
monitor many variables in order to reduce the amount of "dead
burnt" lime which was not useful as an end product. The heating and
cooling process took several days.
These kilns were "draw" kilns. Draw kilns operate under the
principal of gravity. Limestone is fed into the top of the kiln and
the cooked stone is removed from the bed of the kiln. Fireplaces
were located at the sides of the kiln where fuel was burnt to cook
the limestone. One advantage of the draw kiln was that it could be
operated on a continual basis. Even though this type of lime kiln
was more effective than past versions, it was still extremely
inefficient and the lumber needed to fire it could easily
necessitate the clearing of large tracts of woodland.
After the lime was fired it was cooled in cooling sheds and
slaked. Slaking involves adding moisture to the lime; this occurred
in a number of possible ways from sprinkling water on the lime to
letting it sit and absorb water from the atmosphere. The correct
mix is approximately one part lime to one part water. Other
additives were combined with the lime to create various
products.
Limestone (Calcium carbonate)
The limestone mined here dates back to the Silurian Period of the
Paleozoic Era (410-438 million years ago). A common sedimentary
rock, limestone was formed when a shallow sea (possibly as little
as 70 feet in depth) existed over Wisconsin. In this sea
accumulations (reefs) were created by shell and shell fragments
consisting of corals, brachiopods, crinoids and other types of
early life. Many marine organisms extract calcium carbonate from
the seawater to make shells or bones and when these organisms die
their shells and bones accumulate on the seafloor. Over millions of
years these sediments harden into what we see today as limestone.
Calcium carbonate is found naturally as a component of aragonite,
calcite, chalk, marble and travertine.
Uses of Calcium Carbonate-
· As a filler in plastics.
· As an extender in paints.
· As an ingredient of cement.
· To treat animal hides and leather.
· In swimming pools as a pH corrector.
· In agriculture to improve acidic soils.
· In forensic science to reveal fingerprints.
· As a major component of blackboard chalk.
· In adhesives, sealants, and decorating fillers.
· In water and sewage treatment to reduce acidity.
· As a building material in the form of marble or limestone
aggregate.
· Medically as a calcium supplement, antacid or as a base material
for pills.
Look at the kilns, can you find 5 things wrong
with my picture?
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*** KIDS CORNER
***
A long time ago Wisconsin was under a shallow sea. In this sea
lived trillions of tiny snails and other critters. When these
creatures died their shells and bones piled up on the bottom of the
sea. Pressure from other shells, sand and water squashed them
together to form a sedimentary rock known as limestone. This
limestone is what was cooked in the ovens you see here to make
products like plaster for building.
DID YOU KNOW?
Shells are made of calcium just like your teeth!
When limestone is squished really hard it can
become marble.
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LOGGING
REQUIREMENTS:
(Your log may be deleted if you do not follow these logging
requirements)
E-MAIL ME (DO NOT post
in your log)
#1 ESTIMATE: How high are the kilns?
#2 Based on the signage: what element is common in the Grafton
Limestone? Since the sign is gone so is this requirement.
#3 At the quarry: describe the color and texture of the quarry
wall. Are there differences?
(There is no need to climb or otherwise get near the
wall)
POST WITH YOUR FOUND IT
LOG
#4 Upload a photo taken at a recognizable part of the
site and include your GPS in the picture.
Upper parking: N43 18.322 W087 57.333 (walk to
lime kilns from here)
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Lime Kilns: N43 18.306 W087 57.329
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Lower Parking: N43 18.203 W087 57.476 (walk to
quarry from here)
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Quarry: N43 18.245 W087 57.531
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Permission for this Earthcache has
been granted by John R. Safstrom, Grafton Community Activities
Director.
References:
http://en.wikipedia.org/wiki/Lime_kiln
http://www.limehousekilns.ca/history.htm
http://www.co.ozaukee.wi.us/history/LimeKilns.htm
http://www.mpm.edu/collections/learn/reef/grafton-front.html
http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=761565838
http://www.wisconsinhistory.org/