A fine white clay, soft as face powder, plays an important role in a variety of industrial products and provides valuable traffic for the Southern from South Carolina and Georgia.

The clay-called kaolin-is all around you, unseen and unsuspected, in dozens of things you use or wear. It is probably in the magazine page you are reading . . . in the rubber heels on your shoes . . . in the china dishes on your shelf . . . in the porcelain glaze on the kitchen sink . . . in the latex paint you just used to paint the spare bedroom.

Two important factors in the production of kaolin clay: (above) crude clay from which to process the kaolin and rail transportation to move it to the manufacturers who use it.


For kaolin serves industry in numerous ways. As filler and coating agent it adds body and a glossy white surface to printing papers. As an ingredient in natural and synthetic rubber product it increases resistance to abrasion and wear in heels, soles, tiling, flooring, footwear, conveyor belt covers and bicycle tire treads. It is useful, too, in the manufacture of rubber hose, tubing, jar rings, insulated wire, sponge rubber, molded goods, toys and novelties.

Earliest use of kaolin was in chinaware, and it is still an important ingredient in china, pottery and ceramic products. In more recent years kaolin has proved valuable as filler in insecticides, home and industrial adhesives, reinforced plastics and paints.

Prospecting for new clay deposits for United Clay Mines, Inc., near N. Aiken, a drilling rig takes up core samples from a clay strike.


Most of the kaolin produced in this country comes from four counties in Georgia and South Carolina, from deposits that geologists call "sedimentary clays." Of the major kaolin producers in this area five are located on Southern's lines: J. M. Huber Corporation, with plants at Langley and Graniteville, S. C., and Huber, Ga.; Dixie Clay Company, at Bath, S. C., (a subsidiary of R. T. Vanderbilt Company, Inc., New York); National Kaolin Products Company at Natka, S. C.; and Southeastern Clay Company, and United Clay Mines, Inc., both near North Aiken, S. C.

Like all clays, kaolin is basically a hydrated aluminum silicate, plastic when wet and permanently hard when fired. "Clay" refers to a physical condition not to chemical composition. This varies with different types of clay.

Geologists classify kaolin according to its location. "Residual clays" are those found at the point where they were formed by the weathering of rocks such as feldspar and mica. "Sedimentary clays" are those that have been carried by wind or water and deposited elsewhere.

Stripping the overburden of earth from a clay mine of J. M. Huber Corporation near Huber, Ga. The boom on the giant drag shovel is 220 feet long (Note size of truck at lower left.)


The kaolin deposits in Georgia and South Carolina are believed to have been deposited millions of years ago on what was then the shore line, but is now far inland and 300 or more feet above sea level. Marine fossils, such as sharks' teeth, removed from the crude clay give evidence of its seacoast location of eons ago.

Industry on the other hand classifies kaolin by use-paper clays, ceramic clays and "hard rubber" or "soft rubber" clays (depending on the physical properties they give to the rubber products) .The South Carolina- Georgia deposits contain all these types.

Loading crude clay into trucks with a power shovel at Dixie Clay Company's mine near Bath, S. C. Long worked, the mine resembles a Grand Canyon in miniature.


Most of this country's "soft rubber" kaolin comes from this area, and it is believed to produce the entire world's supply of the "hard rubber" variety.

Producing kaolin for the market involves four steps: ( 1) finding the clay in commercially recoverable quantities, ( 2) removing it from the earth, ( 3) pulverizing it and removing impurities, and ( 4) transporting it to the manufacturers that use it.

Dumping crude clay into the storage shed at Southeastern Clay Company's plant near Aiken.


Prospecting for kaolin deposits (which all these companies do regularly) is much like prospecting for oil. The core drilling machine (usually mounted on the back of a truck) resembles a small oil drilling rig- and the prospector is resigned to the fact that hell sink his share of "dry holes" before he strikes clay.

Test holes are usually bored at wide intervals in a random search in promising areas protected by minerals leases.

Lift truck dumps crude kaolin into the slicer at National Kaolin Products Company plant at Natka, S. C.


When a clay deposit is discovered, test holes are drilled at closer intervals. Core samples are taken at every foot of depth in the clay and are run through searching laboratory tests. All this determines the extent, the thickness and the slope of the deposit, how much earth lies over it and the type of clay found ( it varies, even in the same deposit) .

Knowing these results, the company can decide whether there is enough clay to warrant removing the top earth, called "overburden," and if so, at what point to open the mine. (Usual practice is to open the mine at the low end of the slope, so that any ground water that collects will be behind the mining equipment as it moves up along the clay seam.)

View of the interior of United Clay Mines' plant at North Aiken shows (at left in picture) one of the huge rotary driers.


Huge mechanical shovels, drag lines, tractors and graders ship the overburden of earth from the clay, then take out. the crude clay itself for removal to the processing plant. There it is dumped directly or carried by conveyor into dry storage sheds.

Crude kaolin clay is almost white in color and contains from 20 to 25 per cent water. According to the moisture content, it may feel almost dry to the touch, soapy, or slick as mud.

Dried crude clay is pulverized and freed -of grit in roller mills and separators like this one lit National Kaolin Products' Natka, S. C., plant.


In the "drywash" or air flotation method of removing grit and impurities from the clay, drying is the first step., {All the plants on Southern's lines use the "dry wash" method. J. M. Huber Corporation's plant at, Huber, Ga., also employs the wet-process-where clay is suspended a water solution to remove impurities especially for producing filler and coating clay for paper manufacturers.

The plant storage sheds contains mountains of clay, in chunks ranging from pebble to boulder size. Small lift trucks move the crude clay to the slicer. It reduces the clay to small lumps that are fed in a uniform continuous flow to giant rotary driers.

Kaolin is often loaded directly into covered hopper. (Car is at J. M. Huber's Langley plant.)


With all but 1 or 2 percent of its moisture content removed, the dried crude clay is elevated to a storage bin. From there it feeds directly into the roller mills and separators. While the mill rollers grind the clay to a fine powder. upward currents of air lift particles of the desired fineness to collecting bins. A rotary blade separator rejects the coarser particles and grit.

From the collecting bins the finished clay may be piped directly to a covered hopper car on the plant siding or to automatic bag-filling machines that pack the powdery kaolin in multi-wall paper bags, 50 pounds to the bag.

Purity of the finished clay is an important consideration to the manufacturers who use it, and every possible step is taken to protect it.

Kaolin produced by the wet process may be dried afterward but paper coating clays are often shipped in a semi-liquid form as "slurry" in tank cars like this one being filled at J. M. Huber Corporation's plant at Huber, Ga.


From the time dried crude clay drops into the roller mills until the powdered product pours into covered hopper car or paper bag, the clay is in a closed system, with impurities sealed out. Samples of the pulverized clay are laboratory tested in 30 minute intervals.

Weighed automatically as they are filled, the bags of clay look like oversized pillows as they come off the bagging machines. As they travel the roller conveyor to the loading dock, pressure rollers squeeze out the air. This leaves a flat, compact bag-easy to stack directly in the car or to load on pallets for handling by fork-lift trucks.

Stacking bags of kaolin in a box car on the rail siding at Dixie Clay Company's plant at Bath, S. C.


Since many clay users do not have facilities for unloading clay in bulk from covered hopper cars, the majority of the clay shipments from plants on our lines consist of bags loaded in box cars.

Including shipments from plants on line, and those received from connections, Southern handled more than a million tons of clay last year a good share of it kaolin.

Filling and weighing paper bags of kaolin) on the automatic bagging machine (the scene is Southeastern Clay Company's plant, N. Aiken). Note pillow shape of filled bags.


The clay now called kaolin was discovered in China more than 30 centuries ago and added luster to the fine porcelain china of ancient times. There are conflicting stories of how it got its present name.

One credit it to a mixup in tagging the sample bags collected by a British scientific exploring party in China. A tag reading "Koa-ling" (meaning Kao Hill) was accidentally placed on the bag of white clay.

Another story attributes the origin of the name to "Kau.ling" (meaning high ridge) where the earliest samples of the clay sent to Europe were obtained by a French Jesuit missionary in China in the early, 1700's. In any event, the; name has stuck.

Pressure rollers squeeze out air and flatten bags for easy loading. (National Kaolin's plant at Natka, S. C.)


Kaolin deposits along the Georgia-South Carolina fall were discovered in pre-Revolutionary days. , The governor of the province of Georgia had some of the clay brought down river to Savannah and shipped to the famed Wedgewood Potteries in England.

An emissary of the English firm came to Georgia to supervise shipments of the clay, which was sent to England in considerable quantities until the Revolutionary War and the development of fine clay deposits in Cornwall combined to halt the imports.

When kaolin mining along the fall line was resumed almost a century later, the clay was moved by ox cart and mule wagon to Augusta, some of it used locally and the rest shipped by rail to Charleston (via a predecessor line of Southern ) .From there it moved by ship to destinations in the North and East.

Fork-lift truck placing a pallet of bags of kaolin in a box car on the rail siding at United Clay Mines plant.


For years, American kaolin took a back seat to the imported English clays. But American clay producers worked steadily to perfect product and techniques. When the opportunity came (during World War I) they were ready to enter the market in force. Since the late 1920's American clays have dominated the domestic market.

Recent development in preparing bags of kaolin for shipping is this mechanical pallet loader being used at J. M. Huber's Graniteville plant.


Industry has developed a lively interest in kaolin, as more and more uses have been found for the versatile powder.

Stacking bags of kaolin on pallets by hand is the method most widely used in plants served by Southern. (Southeastern Clay Company, North Aiken.)


Southern's interest is readily apparent in the box and covered hopper cars loading at plant sidings to distribute this valuable industrial ingredient to users all across the country.

Southern provides a transportation link between producers and industrial users-an