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?
*** 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.
(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)
Lime Kilns: N43 18.306 W087 57.329
Lower Parking: N43 18.203 W087 57.476 (walk to quarry from here)
Quarry: N43 18.245 W087 57.531
Permission for this Earthcache has been granted by John R. Safstrom, Grafton Community Activities Director.