Thornton Quarry

Carly Herweck
Brookwood Junior High School, Glenwood

Driving down the Tri-State Tollway through the south suburbs of Chicago, one finds a huge hole in the ground approximately 1.5 miles long, .5 miles wide, and 400 feet deep. What is it? It's the Thornton Quarry. This hole in the ground is so vast that the entire village of Thornton could sit comfortably on its floor. It is the second-largest commercial stone quarry in the world.

During the Silurian Period 425 million years ago, when much of North America was covered by a shallow, tropical sea, reefs flourished in the area now occupied by Wisconsin and Illinois. The Silurian was a period of geologic time between 408 and 438 million years ago. The term Silurian comes from Silures, the name of a tribe of people who lived along the border of England and Wales before the time of the Romans. The Silurian Age marked the beginning of coral reef building.

A reef is a structure built by organisms that rises above the surrounding seafloor. Reefs are built in warm, shallow seawater in the tropics and subtropics. They occur only in waters that are relatively free of suspended, land-derived sediment, which allows sunlight to penetrate to the reef surface, permitting photosynthetic organisms to live. The most famous reef unearthed in the Chicago area is the coral reef. Coral reef is a reef constructor that helps to build the reef by forming a framework of hard skeletons. For example, during World War II, ships and planes that sank around the islands were found years later to be turned into coral reefs.

Thornton Reef developed from coral growth centers on the bottom of the ancient Silurian Sea. Debris from the growing reef began to be deposited and cemented. The reefs contained sea lilies, animals resembling horseshoe crabs, and ancient ancestors of squids and octopuses up to ten feet long. The ashy, gray-white limestone mined from the Thornton Reef contains the fossils of these animals. A fossil is a feature preserved in a rock that indicates the presence of ancient life.

During the Silurian Age, the coral took in sea-water and processed out the lime. The lime deposits from the coral hardened and produced limestone. When the coral died, it stayed on top of the limestone and became part of the formation. Young coral then laid eggs on the limestone structure and began the process all over again. The result was coral and other dead sea life encased in layers and layers of limestone.

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Fossils are not the only thing found in the quarry. On June 28, 1994, a meteorite was found. It was estimated to be between 4 and 4.6 billion years old and weighed between 800 and 1,000 pounds. The rock was one of about 1,400 meteorites that have been found on earth. Brian Rice, manager of the quarry, stated, "The meteorite reportedly hit the earth about 407 million years ago. It landed in Thornton when the quarry was a coral reef, part of a huge temperate sea similar to the Caribbean Sea."

The first settlers came to Thornton, Illinois, in 1834. Gurdon Hubbard received 160 acres of land from Shabonna, his Indian wife. In 1836 Hubbard opened the first quarry on Kinzie Street. The site was abandoned because the stone was too deep and of poor quality. Fred Gardner opened a quarry in 1846, and Stephen Crary opened one in 1850. In the early 1900s, Brownell Improvement Company purchased the entire area. Colonel Hodgkins bought the property in 1920. The quarry north of Ridge Road was opened in 1924, and a tunnel connecting the north and south quarries was developed in 1926. Colonel Hodgkins died in 1929, and Brownell repurchased the quarry in 1933. Then in 1938, Material Service Corporation purchased die property and has owned it ever since.

Today Thornton Quarry consists of three large quarries connected by tunnels. It produces aggregates, stone, sand, metallurgical stone, mineral filler, and several other products. Thornton Quarry produces more than seven million tons of rock products, worth about $40 million each year. The rock can be sold as is or ground into dust for use in concrete mixing, fertilizers, or asphalt coatings. Some by-products are asphalt shingles, tar paper, building materials, and undercoating for cars.

Things last in Thornton, a town where many businesses and families go back several generations. In the early 1900s, about six hundred workers emigrated from Hungary and Austria to work the quarry, most of them relatives of people who had already come to the area. They lived in barracks set up just to the south of the quarry. The town's economy grew from the sales of food and other necessities. "Many of the men who came over to work the quarry stayed, and their families still live in the area," commented Walter Diekelman, the town's longtime fire chief and unofficial historian.

Today, the Thornton Quarry provides 10 percent of the town's annual budget, which is about $1.2 million. Material Service pays Thornton a $100,000 annual fee that takes the place of a mining tax. The company also helps Thornton clear the dust created by the stones carried by the many trucks that rumble down the town's main streets. They not only sweep the town, but they pick up leaves and help dig the town out after a heavy snow-fall.

By the year 2002, Thornton Quarry will have another use. It will be a reservoir for runoff and sewage. This project, Chicago's Deep Tunnel, is being constructed for drainage purposes. The reservoir will have a capacity of 3.1 billion gallons of overflow, but it will make way for a permanent reservoir in 2014, which will have a capacity of 4.8 billion gallons.

In conclusion, Thornton Quarry played a main role in Illinois' past. It has been producing stone since long before the turn of the twentieth century.—[From "Chunk of History Found in Quarry; It's a Meteorite," The Star (Homewood-Flossmoor), Sept. 11, 1994; "Digging History," The Star (Homewood-Flossmoor), Nov. 5, 2000; Illinois State Geological Society, "Thornton Quarry Rocks," www.isgs.uius.edu/news/geonews/july97/thornq (Oct. 10, 2001); Material Service Corporation, "This is the Thornton Quarry"; Milwaukee Public Musem, "The Virtual Silurian Reef-Introduction," www.mpm.edu/reef/into (Nov. 1, 2001); Milwaukee Public Museum, "The Virtual Silurian Reef-The Silurian Period," www.mpm.edu/reef/concept-silurian (Nov. 1, 2001); Milwaukee Public Museum, "The Virtual Silurian Reef-Reefs," www.mpm.edu/reef/concept (Nov. 1, 2001); Milwaukee Public Musem, "The Virtual Silurian Reef-Silurian Reef at Thornton, Illinois," (Nov. 1, 2001); "Our Debt to Deep Tunnel," The Star (Homewood-Flossmoor), Oct. 7, 2001; "Quarry Tells Region's History," The Times (Northwest Indiana),June 10, 2001; "Tiny Thornton: Big Heart and Quarry to Match," Chicago Tribune, Oct. 26, 1985; Village of Thornton Historical Society, "Neighbors Have Learned to Live with the Quarry"; Village of Thornton Historical Society, "Thornton Quarry."]

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