Plan 5.1 The foundation plan of the Alahana Pirivena in Polonnaruwa. This
hospital was used from the time of King Parakramabahu I.
The Ancient Iron Leaching Technology
From very ancient time our ancestors knew the
iron leaching technology well. The archaeologists
were able to discover a piece of iron- slag from a
tomb dated in 2400 B.C. in Beragala in the Uva
province. It is a piece of evidence which reflects
that the iron was melted in those days.
There are two instances which assist us
to understand the nature of iron leaching
technology in Sri Lanka. The first one among
them is the iron melting furnaces found in the
Samanala Wewa area in Balangoda
in the Sabaragamuwa province. The
second one is the ancient iron furnaces
discovered in the Alakolawewa,
Dehigaha Elakanda area close
to Sigiriya which belongs to the
Central province. The natural stones
abundant with iron have to be heated
much to leach iron from them. Iron
melts at 1538 degree Celsius. There
should be an efficient technology to
get an excessive-temperature. Iron
leaching in Samanala Wewa has
been done in third century B.C. The
natural wind power has been used to
inflame the furnaces used for melting.
The furnaces built in a mountain-
face would flame for nearly about 12
hours without extinguishing with the
help of the wind blowing between the
hills. Even today during the monsoon
time the wind, which blows across
that area in the evening, continues
until the dawn of next day. The
natural stones with iron that were
put into the furnaces after breaking
them into pieces would be inflamed
by placing cinders on them with the
help of the natural wind power in
the evening which would blow until
the following dawn. By the following
morning iron would be leached from
the stones. The stones, which were
used in Samanala Wewa to leach
iron, are the types introduced in the
terms ‘Limonite’ and ‘Hematite’ in chemistry. To
inflame those furnaces, they had used the cinders
taken by burning the trees called ‘Maran’. Even
now these trees can be seen in this province. The
term ‘Yakada Maran’ too is used to name these
trees.The wind power to inflame the furnaces in
Dehigahaelakanda area has been provided with
the help of bellows. From 180 B.C. to 200 A.D.
iron leaching had been done there.