In Middle Georgia
THE FALL LINE
The origin of kaolin can be traced to the Cretaceous geologic period, about
70 million years ago when dinosaurs roamed the earth and much of the southern
half of Georgia was covered by a great sea. The climate was more tropical
than now. The seacoast stretched across Georgia from Columbus to Macon to
Augusta along a line that we now call the "Fall Line" where the
Piedmont gives way to the coastal plains.
WEATHERING OF THE PIEDMONT ROCKS
50-56 million years ago
Weathering of the rocks of the Piedmont generated large volumes of kaolinitic
clays, quartz sand and mica, as well as minor amounts of other minerals, especially
iron and titanium oxides, such as limonite and anastase. Feldspar, a major
component of granitic rocks such as those at Stone Mountain near Atlanta, is
considered the parent material for most of Georgia's sedimentary kaolin.
TRANSPORTATION AND DEPOSITION OF SEDIMENTS
50-65 million years ago
Washed into rivers and streams, the weathered clays and sands of the Piedmont
were transported and deposited in swamps, marshes and lagoons near and along
the coastline of the ancient sea. Iron and titanium oxides were often deposited
along with the kaolin, contaminating and making much of the kaolin unusable
for commercial applications.
Changes in the sea level interrupted the sequence of erosion, transportation
and deposition of kaolin from the Piedmont, but the process continued for some
30 to 35 million years. The last invasion of the land by the great sea deposited
huge amounts of red and brown sands and clays over the kaolin deposits. These
later sediments formed the characteristic red hills of Middle Georgia. They
covered many of the kaolin deposits with more than 200 feet of material, rendering
these deposits uneconomical to mine. A typical cross-section of Coastal Plains
Sediments showing the bedding or layering of the sediments and the position
of the kaolin beds.
THE KAOLIN BELT
Kaolin is one of the many industrial minerals mined in Georgia today. The commercially
mineable kaolin deposits are found in a relatively narrow "belt" along
the Fall Line. The kaolin mining industry has located its processing facilities
in the communities near the deposits, primarily in the nine rural counties
between Macon and Augusta. Highly technical equipment and processes are employed
to transform the crude kaolin into high quality products which are marketed
around the world for a wide variety of applications.
EXPLORATION, DRILLING, SAMPLING AND TESTING
Kaolin mining begins with exploration. Based on local stratigraphy,
geologists identify lands with potential for mineable deposits. Landsmen negotiate
with the landowner for the rights to explore and mine. Contracts usually take
the form of mineral leases that pay royalties or options to purchase. Commercial
quality deposits are located by surveying, drilling, sampling and testing.
Because of contaminants and extreme overburden, only a portion of the land
explored contains commercial quality kaolin.
LOCATING THE MINE BY SURVEY
The exact location of the opening to be made in the earth is laid out on the
ground. The opening is referred to as a "cut" and its location and
dimensions are based on the survey, drill and test information developed during
exploration of the land.
SECURING A MINING PERMIT
Before moving any earth, a mining permit must be secured from the State. Company
mining engineers and geologists develop a written mining and reclamation plan
with maps and photographs. The plan is submitted to the State for evaluation
and approval and contains measures for erosion and sediment control and protection
of adjacent land and water resources. The reclamation plan includes grading
and contouring the land and establishing a permanent vegetative cover. Frequent
9 inspections are made to assure compliance with the approved plan.
SITE PREPARATION, ENVIRONMENTAL PROTECTION, AND OVERBURDEN STRIPPING
Following State approval, the landowner removes any merchantable trees
from the mining site. Erosion and sediment control structures are built. These
usually take the form of berms, sediment fences and impoundments for collecting
run-off water and sediments. When these structures are in place, stripping
of earth or overburden can begin according to the mining plan. Mining cuts
are usually 2-5 acres in size.
PONDS, LAKES AND WILDLIFE
When mining is completed, the last mine cut may be made into a lake or pond
if sufficient water is available. Construction must be approved by the State
as a part of the reclamation plan. The water is fertilized to produce a desirable
environment for fish and waterfowl and usually stocked with bream and bass
and sometimes catfish.
THE CYCLE IS COMPLETE
The volume and quality of the deposits, as well as market applications, usually
determine the life of a kaolin mine. Blending of low and high quality deposits
conserves and extends reserves, but requires the simultaneous operation of
several mines over many years. The objective of kaolin mining is to profitably
extract a useful and beneficial industrial mineral and then to return the
land to a stable and productive use. Reclamation completes the cycle. The
land again produces renewable resources such as timber and agricultural products,
wildlife and fish, and recreation for present and future generations.