In
Siam, ruby and sapphire occur together in the province of Chantabun and
Krat in the south-east, and was known only in alluvial deposits. The
Siam sapphires are also of good colour and quality.
A
large stock of sapphires is believed to be kept in the Kashmir treasury
on account of its location. The mining of sapphires could not ba
carried throughout the year.
Gem
mining is never attempted on solid rocks, since gem minerals are only
sparingly and sporadically distributed. Nature has broken down large
masses of rock, leaving the gem-stones in the more easily worked debris.
The
ruby mines of Burma are known to be working since the fifteenth
century, under the close supervision of the Burmese kings. On the
annexation of Burma by the British, the Burma Ruby Mines Co. was
floated in London in 1885. This firm worked for forty years and went
into liquidation in 1925, and had produced £2-1/2 millions worth
of gem-stones. One of the famous rubies, obtained from this area is the
'Peace Ruby' found on the Armistice day in 1918, whose weight when cut
was 23 carats. It was sold for Rs.3 lakhs. The Burma Ruby Mines Co.
mostly worked at,a loss and on its liquidation, ruby mining on modern
methods also came to an end. One of the reasons for this was the
flooding of the market with synthetic rubies.
The
operations of this concern were confined to removing and washing
gravels from valleys in the neighbourhood of Mogok, Kyatpyin, Kathe and
Luda valleys. These are the centres where mining activity is still
present. Mining on extraordinary licence was carried to a small extent
with modern machinery. The indigenous mining methods are still pursued
and are ever likely to continue, since mining on a large scale with
machinery has proved unremunera-tive. There are three methods of mining
in vogue depending on the season and the nature of the country.
(i) Twinlons or Twin-Mining in the dry season.—It consists of small round pits, the diameter of which will
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