Bentonite
may have played a major role in Fuller’s earth formation.
By
Dr. Nitish Priyadarshi
Fig. Fuller's earth.
Fig. Mining area.
Fig. Bentonite.
Pakur is located in
the north east corner of Jharkhand State of India. Major part of the district
is characterized by undulating topography covered by basaltic flows of Rajmahal
Trap. Fuller’s earth mining is limited up to a shallow depth only and it is
done manually. Most of the Fuller’s earth is send to local market of Pakur and
neighboring state of West Bengal. Local
villagers have the ownership of the mining and the profit is distributed among
them. Fuller’s earth is mainly of sedimentary origin. It occurs interstratified
with geologically late sands and clays. It is thought that most fuller’s earth
originated from volcanic ash. Montmorillonite and attapulgite are the principal
constituents, and montmorillonite is characteristic of bentonite. There is
further suggestion that it was derived from bentonite by natural leaching in
surface water, assisted perhaps by plant acids and bacteria.
Discussion:
Pakur is located in the north east corner of Jharkhand State: at 23°40' to 25°18' latitude and 86°25' to 87°57' E. longitude. Pakur is bordered by Sahibganj district in North, Dumka district in South, Godda district in West and Murshidabad and Birbhum districts (of the West Bengal) in the East. Pakur has an area of about 696 square kilometres and a population of 899,200 (2011 Census). Pakur, famous for stone and Beedi (Biri) making industry, is one of the important revenue-earning districts of newly created Jharkhand State. Its black stone chips have got Asiatic fame in constructional qualities.Pakur was earlier a Sub-Division of Santhal Parganas district of Jharkhand.
Major part of the district is characterized by undulating
topography covered by basaltic flows of Rajmahal Trap. The main
geomorphological features of the district are the rolling peneplain in the
south with numerous remnants of ancient ridges and resistant lava plateau of Rajmahal.
These plateaus rise above the general level and occupy major part of the
district. The general elevation of the hills and plateau varies from 70 to 371
m above MSL.
Rajmahal Trap is the major rock type in the district. The
other geological formations of the district are alluvium, laterite and gondwana.
In the eastern part of the district, recent alluvium occurs in patches, which
is mainly composed of sand and sub ordinate clay. Laterites are mainly of in
situ origin and have been formed by sub-aerial erosion of underlying basalts
under favorable climatic conditions. Laterites provide a productive ground
water reservoir due to their very porous
and permeable nature. The most significant
Barakar coal measures of Gondwana formation occurs in western part of
the district.
The district of Santhal Paraganas is mainly a dissected
upland of ancient crystalline rocks which are covered with thick flows of
volcanic lava. The ancient crystalline rocks, collectively called the Archaean
gneisses, cover the greater part of the district. The principal rock is a
granitoid gneiss earlier known as the Bengal
gneiss.
Fuller’s earth ( commonly known as Multani soil) mining is limited up to a shallow depth only
and it is done manually. Most of the Fuller’s earth is send to local market of
Pakur and neighboring state of West Bengal.
Local villagers have the ownership of the mining and the profit is distributed
among them.
Fuller’s earth is a variety of clay, so named because it has
been used by fullers to full, or remove grease from cloth. Its marked absorptive
powers, however, have caused it to be more widely used to filter and decolor
oils, fats, and greases.
The dominant use (about 70 percent) of fuller’s earth is in
petroleum refining for filtering and clarifying petroleum products, mainly
lubricants, and about 10 percent is utilized in the refining of vegetable oils
and animal fats. Its use is growing in domestic water purification. It also
removes putrescence, odors, and even coliform bacteria from oily waste waters.
In oil refining, colored oils passed through fuller’s earth
come out colorless. In addition, it removes naphtha gum, and improves the
sludge and carbon content, acidity, and viscosity of lubricating oils. It
removes color, odor, and taste from vegetable and animal oils. Fuller’s earth
cannot be reused after filtering vegetable oils.
Minor uses include printing, abrasives, detection of
coloring agents in food products, filler, and cosmetics. Fuller’s earth is a
clay substance that is hugely popular for its healing property against acne and
blemishes. It is very rich in magnesium chloride which helps to reduce
acne. In oil refining fuller’s
earth is being displaced by activated bentonite.
Fuller’s earth is mainly of sedimentary origin. It occurs
interstratified with geologically late sands and clays. It is thought that most
fuller’s earth originated from volcanic ash. Montmorillonite and attapulgite
are the principal constituents, and montmorillonite is characteristic of
bentonite. There is further suggestion that it was derived from bentonite by
natural leaching in surface water, assisted perhaps by plant acids and
bacteria. Ash deposited in situ becomes bentonite; that which is gradually
washed in, with leaching of grain surfaces, become fullers earth. Extended
weathering of fuller’s earth may yield Kaolin.
Reference:
Bateman, A.M. 1955. Economic mineral deposit. John Wiley
& Sons, Inc. New York.
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