Gemstone Mining
Famous International Gem Mines
Sri Lanka
Sri Lanka is situated in the Indian Ocean south-west of India.
It is bordered by the Indian Ocean to the north, south, east
and west. It is located a few degrees north of the equator
and is the 24th largest island covering some 25,332 square
miles.
The population is approximately 14 million comprising of
79% Sinhalese, 13% Tamil (both South Indian & Sri Lankan Tamils)
and 7% Moors.
Sri Lanka was formerly known as Ceylon until May 22nd, 1972.
Ceylon is the ancient Sinhalese name meaning "Resplendent
Land",also known as SERENDIB or TRAPROBANE to ancient navigators.
The climate and vegetation are both tropical. Warm and humid
at sea level (average temperatures 78 F to 82 F), the humidity
during the day can be 70% (at night 90%). In the mountainous
regions, average temperatures are 60 F. The monsoon seasons
are from May through June and September through November.
Average rainfall varies from below 40 inches in the dry northern
zone and on the eastern slopes of the mountains to over 200
inches in some places on the south-western slopes. March to
April are the hottest months.
Sri Lanka is an important source for not only gems but also
tea, spices, rubber and coconuts. Approximately 2/3rds of
the cultivated land and 2/3rds of the population are involved
in the production and distribution of these products. Tea,
rubber, coconuts and rice make up 95% of the countries exports
and account for 75% of the cultivated land. Tea brings in
over 66% of the yearly income from exports. In fact, Sri Lanka
is the second largest producer of tea.
Rubber accounts for 15% of the yearly export income and coconuts
account for 14%.
Gems continue to be a small and significant product of Sri
Lanka and has supplied the world with fine Rubies and Sapphires
for over 2,000 years. Many consider Sri Lanka to be the original
source of Ruby and Sapphire.
Although Burma has produced finer qualities, Sri Lanka has
produced Rubies and Sapphires in larger sizes for longer periods
of time.
All varieties of Corundum are found in Sri Lanka including
the "PADPARADSCHA" which is unique to the island.
Main Gem Centres of Sri Lanka
- Ratnapura : The oldest known source in Sri Lanka, meaning
"City of Rubies" or "City of Gems".
- Elehara District : important in recent years for producing
large and fine specimens of many gems including Sapphire
and Cat's Eye Chrysoberyl.
- Area around Morawaka : known for Alexandrite and Cat's
Eye Chrysoberyl.
- Nuwara Eliya : situated in the mountainous tea country.
Mining
Mining in Sri Lanka is mainly alluvial with gem deposits
found not only in present river systems but also below rice
paddies where ancient rivers once flowed.
The depth of the gem gravel or "ILLAM" varies from 3m to
20m to as much as 40m at Pelmadulla.
The search for gems is a highly speculative operation and
is usually carried out by a group of native workmen on a share
basis. 1/5th goes to the owner of the land, 1/5th to the financier
and the rest goes to the workers.
Access to these gem producing areas is often limited especially
during the monsoon seasons. When the word spreads that a miner
has struck paydirt, the area is soon inhabited by treasure
seekers who dig pits everywhere. These pits are usually dug
very close together with somewhat thin retaining walls between
them. Pits can be up to 50 feet deep and are hazardous at
night to both humans and animals. Deserted pits, left with
standing water, become breeding grounds for mosquitoes and
the resulting malaria is constantly challenging the local
governments.
Pits are normally worked by 4 workers, one to fill the baskets
with "ILLAM", one to throw it to the top, one to catch it
and one to take it to the washing area.
Water is a big problem especially with the high water table
that some areas have. It must be constantly bailed or pumped
out using petrol-operated pumps since by law, only the simplest
of equipment is allowed in Sri Lanka. Only in areas slated
to be submerged due to the construction of large dams for
hydro-electric projects has the government allowed modern
mining methods.
Although the many restrictions have hindered the progress
of the gem industry in Sri Lanka, it has provided prolonged
employment for thousands of needy villagers.
Once the gem gravel reaches the central washing area, it
is emptied into deep conical baskets which are large enough
to wash approximately 20 basketfuls of illam at a time.
The art of washing is reminiscent of panning for gold with
the water carrying the mud and lighter stones through the
fine mesh and over the top of the basket. This leaves the
heavier materials clean and concentrated at the bottom of
the cone.
The sorting is carried out by one who is expert in the recognition
of rough gems. First the larger fine precious stones are removed
(known as JATHI) and given to the financier of the project
for safekeeping. The residual (known as TOURA-MALI) is handed
to another man to ensure that nothing has been missed.
The Sri Lankan gem gravels also produce zircon, tourmaline,
peridot, quartz, garnet, feldspar and a number of other stones.
Diamonds, opal and emerald are not found on the island.
Thailand
Thailand is bordered by Mayanmar and Laos to the north, Laos
and Cambodia and the Gulf of Siam to the east, Malaysia to
the south and the Andaman Sea and Burma to the west.
It was formerly known as Siam until 1939 when it became known
as Thailand.
Allied to the Japanese in the Second World War, the name
was abandoned in 1945 by the pro-allied free Thai government
to expediate peace negotiations with Britain but was revived
in 1948.
Although Thailand has been a constitutional monarchy since
1932, political power long resided with the military regime.
In 1973, the military regime of KITTIKACHORN was overthrown
by student uprising and replaced by a civilian government
in 1975.
Thailand covers some 514,000 square kilometres. It's population
is approximately 55.5 million. The capital is Bangkok.
Thailand is unique in that it is the regions only nation
to have avoided the experience of colonial domination and
has therefore been able to preserve much of its traditional
society, religious traditions and ancient India-derived conception
of governmental authority.
The climate is hot and humid most of the year. In the central
valley, temperatures rarely go below 65 F in the coolest months
(December / January) and extend upward to around 100 F from
March to May.
The rainy season extends from June through September. The
central valley lies in the rain shadow of the Mayanmar mountains
to the west and receives annual precipitation of 40 inches
compared to 220 inches in Mayanmar. The vegetation is tropical.
Gem quality Corundum are found at three major localities
in Thailand and neighbouring Cambodia.
Gem Localities
Chanthaburi, Trat, Pailin
- Khao Ploi Waen : thought to be the first place in Thailand
where Corundum was found.
- Bang Kha Cha Gems Found : Blue, green, yellow and black
star Sapphires
- Bo Waen : Ruby only
- Bo Na Wong : Ruby only
- Wat Tok Phrom : Ruby only
- Ban Bo I-Ram : Very deep Blue Sapphire
- Nong Bon : Ruby - larger stones
- Bon Rai : Ruby - finer colours
- Pailin Fields : Ruby
Best known for Blue Sapphires ranging in colour from medium
to deep blue, considered among the worlds finest.
Bo Ploi, Kanchanaburi
Considered to be Thailand's major source of Blue Sapphires.
It was discovered in 1919 and also produces the occasional
yellow, pink and star Sapphires.
The Blue Sapphires strongly resemble the heat-treated blue
sapphires from Sri Lanka. Most are sold in parcels of Sri
Lankan goods because of the preference for Sri Lankan blue
sapphires.
Phrae Province
Although this area has been known since the 1920's, it has
only been worked since the 1970's. The area produces mainly
Blue and Green Sapphires. The blues are a very deep inky-blue
sometimes slightly violet. Large sizes 5cts or more are rare.
The smaller gems are usually cut as melee due to the deep
colour. Phrae Province is considered the least important in
terms of production.
Mining
There are two types of mining in Thailand.
- Primitive Pit Mining
- Mechanized Mining
As a general rule, access is limited into many of the gem
producing areas. At BO WAEN, BO NA WONG, WAT TOK and BAN BO
I-RAM, access is very poor although a number of large mechanized
mines are found. At NONG BON and BO RAI access is good and
it is at these two sites, where Thailand's largest mines can
be found.
In the dry season, the roads are extremely dry and dusty
but during the rainy season, the roads become almost impassable
except by four-wheel drive. In some cases, the mud can be
several feet deep and often crudely built bridges are washed
away during the summer rains.
Most of the mining in the Chanthaburi area is alluvial. If
gem indications are found, the jungle can be uprooted and
cleared in a matter of days. What remains is an open clay
field where gems may be found at depths of only 3 to 5 feet.
When gems are found, local villages spring up quickly with
housing made of regional timber and tin roofs to protect against
the monsoons. Many houses are not enclosed within walls. Digging,
washing and sorting are all carried out in the backyards.
Generally, one worker will remove the earth at the bottom
of the pit and another will man a bamboo lift which brings
the earth to the surface. After sufficient quantities have
been brought to the surface, the earth is placed in either
bamboo trays (similar to Sri Lanka) and washed in small man-made
pools or placed in large sluice boxes, screened at one end.
High pressure water is forced onto the gravel, washing away
the loose clay which runs as mud and water through the screens.
Washing may take up to an hour leaving pure gravel behind.
As the gravel is sorted, the sorter usually puts the gems
into his mouth and when his mouth is full or the basket is
empty, they are put into parcels. Sometimes they are put into
plastic bags filled with water to intensify the colour and
magnify the size to potential buyers.
A more costly venture in a major producing area is the use
of a bulldozer. Using this method, the jungle and overburden
can be stripped in a matter of hours. The remaining soft clay,
can then be eroded away using powerful water hoses and the
resulting mud is "vacuumed" away by the second miner and directed
towards the sluice boxes.
The mud is then filtered through the screens built into the
bottom of the sluice boxes leaving the gem gravel behind.
Chanthaburi is famous for its household industry in the cutting
and polishing of gems. These include not only locally mined
gems but also gems from around the world. Almost every home
has a grinding wheel and one or more polishing wheels. Both
hand and power driven machines are used.
After the preforming has been done, the final polish is
placed on the stones. The stones are "dopped" and propped
against a make-shift ledge with all the angles and finished
polish estimated by the naked eye.
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