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##Quality Control
Quality control
is performed during several steps throughout the process. The first step
in Q.C. is in the actual classification of the crude Clay prior to
mining. Once the stripping of the Clay begins, each crude grade is
transported to the plant with dump trucks and placed in covered storage
sheds. A representative sample is taken from each truck as it is
unloaded in the stockpile. A composite is formed from these samples.
This composite receives the same testing as the core samples that were
mentioned earlier. This is the first check to assure that the actual
Clay grade being mined conforms to the data shown on the mining plan
that was developed from the core and composite testing.
Once
the individual crude Clays are tested and stored in the sheds, they are
ready for use in the production process. Each finished product has its
own specifications or "specs". These specs are based on established
parameters in our plant, as well as the parameters required by each of
our customers. The types of specifications vary depending on the
industry in which the product is used. Each industry is interested in
only those parameters that affect their process capabilities and the
individual finished products. For example, the Sanitaryware Industry is
primarily interested in casting rate and green strength while the
Fiberglass producers are primarily concerned with residue, iron and
carbon content.
In
order to produce a specific finished grade of China Clay, the crude
Clays are blended proportionately to achieve the specification required
by the customer. While the product is being produced, a sample is taken
every 30-60 minutes from the exit end of the dryer or roller mill. The
required testing is performed on this sample and the process is
adjusted, if necessary, to maintain uniformity in the finished product.
SPC run charts are used to guide these adjustments. Clay is produced on
a "order per order" basis. Once each specific order is completed, a
composite sample is obtained by mixing all the remaining Clay obtained
from the production sampling. A retained sample of this composite is
maintained for six months. This is done so that in the event a consumer
has any problems or questions concerning that specific shipment we can
check the properties the Clay had prior to shipping. This composite
sample and the individual production run samples are used to generate
histograms and/or Certificate of Analysis as required by each customer. |