Chat (mining)
Encyclopedia
Chat is a term for fragments of siliceous rock
, limestone
, and dolomite
waste rejected in the lead-zinc milling operations that accompanied lead
-zinc
mining in the first half of the 20th century. Historic lead and zinc mining in the Midwestern United States
was centered in two major areas: the Tri-State area
covering more than 2500 square miles (6,475 km²) in southwestern Missouri
, southeastern Kansas
, and northeastern Oklahoma
and the Old Lead Belt
covering about 110 square miles (284.9 km²) in southeastern Missouri. The first recorded mining occurred in the Old Lead Belt in about 1742. The production increased significantly in both the Tri-state area and the Old Lead Belt during the mid-19th century and lasted up to 1970.
Trend, in southeastern Missouri. Mining and milling of ore produced more than 500 million tons of wastes in the Tri-State area and about 250 million tons of wastes in the Old Lead Belt. More than 75 percent of this waste has been removed, with some portion of it used over the years. Today, approximately 100 million tons of chat remain in the Tri-State area. The EPA
, the states of Oklahoma, Kansas and Missouri, local communities, and private companies continue to work together in implementing and monitoring
response actions that reduce or remove potential adverse impacts posed by remaining mine wastes contaminated with lead, zinc, cadmium
, and other metals.
separation are typically sand and silt size and are called “tailings
.” Milling produces large chat waste piles and flat areas with tailings deposited in impoundments. Tailings generally contain higher concentrations of heavy metals
and therefore present a higher risk to human health and the environment through direct contact. Chat typically ranges in diameter from 1/4 to 5/8 inch. Intermingled material such as sands
measure 0.033-0.008 inches in diameter and fine tailings are less than 0.008 inch (0.2032 mm) in diameter.
Siliceous rock
Siliceous rocks are sedimentary rocks that have silica as the principal constituent. The most common siliceous rock is Chert other types include Diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, or some types of sponges....
, limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
, and dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
waste rejected in the lead-zinc milling operations that accompanied lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
-zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
mining in the first half of the 20th century. Historic lead and zinc mining in the Midwestern United States
Midwestern United States
The Midwestern United States is one of the four U.S. geographic regions defined by the United States Census Bureau, providing an official definition of the American Midwest....
was centered in two major areas: the Tri-State area
Tri-state area
There are a number of areas in the 48 contiguous United States known as tri-state areas where three states either meet at one point or are in proximity to each other. The best known of the latter type is the New York metropolitan area...
covering more than 2500 square miles (6,475 km²) in southwestern Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
, southeastern Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
, and northeastern Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
and the Old Lead Belt
Lead Belt
The Southeast Missouri Lead District, commonly called the Lead Belt, is a lead mining district in the southeastern part of Missouri. Counties in the Lead Belt include Saint Francois; Crawford; Dent; Iron; Madison: Reynolds; and Washington...
covering about 110 square miles (284.9 km²) in southeastern Missouri. The first recorded mining occurred in the Old Lead Belt in about 1742. The production increased significantly in both the Tri-state area and the Old Lead Belt during the mid-19th century and lasted up to 1970.
Cleanup
Currently production still occurs in a third area, the ViburnumViburnum, Missouri
Viburnum is a city in Iron County, Missouri, United States. The population was 825 at the 2000 census. The city is located in the New Lead Belt.-Geography:...
Trend, in southeastern Missouri. Mining and milling of ore produced more than 500 million tons of wastes in the Tri-State area and about 250 million tons of wastes in the Old Lead Belt. More than 75 percent of this waste has been removed, with some portion of it used over the years. Today, approximately 100 million tons of chat remain in the Tri-State area. The EPA
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
, the states of Oklahoma, Kansas and Missouri, local communities, and private companies continue to work together in implementing and monitoring
response actions that reduce or remove potential adverse impacts posed by remaining mine wastes contaminated with lead, zinc, cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...
, and other metals.
Ore processing
Ore production consisted of crushing and grinding the rock to standard sizes and separating the ore. Ore processing was accomplished in either a dry gravity separation or through a wet washing or flotation separation. Dry processes produced a fine gravel waste commonly called “chat.” The wet processes resulted in the creation of tailing ponds used to dispose of waste material after ore separation. The wastes from wetseparation are typically sand and silt size and are called “tailings
Tailings
Tailings, also called mine dumps, slimes, tails, leach residue, or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore...
.” Milling produces large chat waste piles and flat areas with tailings deposited in impoundments. Tailings generally contain higher concentrations of heavy metals
Heavy metals
A heavy metal is a member of a loosely-defined subset of elements that exhibit metallic properties. It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight,...
and therefore present a higher risk to human health and the environment through direct contact. Chat typically ranges in diameter from 1/4 to 5/8 inch. Intermingled material such as sands
measure 0.033-0.008 inches in diameter and fine tailings are less than 0.008 inch (0.2032 mm) in diameter.
Uses for chat
Chat can be used to improve traction on snow-covered roads; as gravel; and as construction aggregate, principally for railroad ballast, highway construction, and concrete production.External links
- The Creek Runs Red site for Independent LensIndependent LensAiring weekly on PBS through ITVS, the Emmy Award-winning series Independent Lens introduces new drama and documentary films made by independent filmmakers. Past seasons of Independent Lens have been presented by hosts Angela Bassett, Don Cheadle, Susan Sarandon, Edie Falco, Terrence Howard, Maggie...
on PBSPublic Broadcasting ServiceThe Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia.... - Oklahoma Department of Mines website
- EPA Tri-state Mining District chat regulations