'GAZETTEER OF PERSIA. VOL. III. PART II: L to Z' [‎267r] (538/988)

SHA—SHA
886
In cases where the mineral has been more rapidly produced and the
centres of segregation numerous and close to one another, the resulting
nodules soon impinge on one another, unite and include in their interstices
as much as 50 or 60 per cent, of foreign matter. In some few cases lumps
of pure borate have been formed weighing as much as 30 to 40 lbs. when
dry and containing only a few per cent, of sand or earth.
Considerable areas are covered with firm gypsum, above which ulexite
has been deposited, but it is useless on account of the extreme difficulty
attending the separation of the flaky gypsum crystals.
Ulexite is never found at a greater depth than 1 foot and very rarely does
it exceed 8 inches. Much of the corroded mineral appears on the surface
and continues to a depth of 1 to 6 inches. The best mineral, however, is
always found beneath a layer of moist gypseous sand 3 to 4 inches in thick
ness and seldom reaches over 6 inches below. This 2 to 6 inches of ulexite
is never a solid mass but it is in reality a stratum of moist sandy material
containing the white nodules in larger or smaller quantity just like potatoes.
The Sohrab borate deposits .—A group of low hills lie between these deposits
and those of Deh-i-Shutoran.
In a hollow between the spurs of these hills is a branch of the main Kavir
and in this the borate is found. The total extent of the mineral-bearing
area is about 700 yards by 250 yards. The mineral is much more sparsely
distributed than at Deh-i-Shutoran.
Collecting the mineral. —Shovels and bags are the only tools necessary
for the work. Several men go ahead to find the good spots and others
follow and collect the lumps and nodules of borax. Three workmen are able
to oollect from 1 to kharver of borate a day (650 to 975 lbs.).
Drying. —The mineral is emptied on the ground by the people who bring
it. It is thus in a layer 2 to 3 inches thick, exposed to the sun for four or
five days, being turned once, when it is gathered and heaped against the
walls for dressing. The dressing is done by small boys and old men.
The borate contains about 30 per cent, water.
Refining as conducted by natives. —A quantity of crude soda, say 5 bat
mans (3'25 lbs. avoir.), is boiled three or four hours, after which the boiling
is discontinued to allow the mud to settle at the bottom of the boiler, from
which it is taken out with flat spoons. Then some 5 batmans of the
mineral slightly crushed is put in with the solution of soda and boiled.
An hour later the water is let off. When the boiling is stopped the mud
settles and leaves a clear solution of soda and borax in the boiler. This is
put into clay pots to rest 6 to 10 hours. A crust of soda forms at the top
whilst some forms a deposit at the bottom of the pots. The upper crust of
soda is removed and the solution is boiled again to evaporate the water.
What remains in the boiler is then taken out, made into round cakes and
left to dry. This refined borate is then ready for transport.
The great disadvantage of this system is the quantity of soda which still
remains in the refined product. Furthermore, the boiler, being made of
common thin copper sheets and occasionally only being thick wrought
copper boilers, the metal gets corroded and the refined borax becomes of a
greenish or brownish colour. The refined product also contains a small
admixture of mud or earthy substances.
3q