Transcript Slide 1

DIAMOND MINING
CONTENTS
 INTRODUCTION
 IMPORTANT DIAMOND PRODUCING COUNTRIES AND
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COMPANIES IN THE WORLD.
TYPES OF DIAMOND.
TYPES OF DIAMOND MINING
MINERAL PROCESSING OF DIAMOND
DIAMOND MINING IN INDIA
TYPES OF DIAMOND MINING
CONCLUSION
INTRODUCTION
 Diamond is a transparent gem made of carbon
 The Diamond came from the Greek word adamas which
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means unconquerable
Diamond forms in the kimberlite pipes
The formation of diamonds began very early in the
earth's history
The centre of the planet to become subjected to
incredible extremes of temperatures and pressure.
It was these conditions that caused deposits of carbon to
begin to crystallise deep in the earth.
 As the earth's surface cooled, volcanic activity forced
streams of magna (liquid rock) to the surface,
carrying with it the diamond crystals.
 Later, the diamond-bearing rock hardened, encasing
the diamonds in vertical volcanic "pipes".
 Subsequent erosion of the topsoils over millions of
years washed some of the diamonds into streams and
rivers, and sometimes as far away as the sea.
 The diamond is thousands of times harder than
corundum, the next hardest substance from which
rubies and sapphires are formed.
PROPERTIES
 Chemistry – C
 Class – Native Mineral
 Sub class – Non Metallic
 Group – carbon
IMPORTANT DIAMOND PRODUCING
COUNTRIES
AFRICA
Angola, Botswana, South africa
AUSTRALIA
NORTH AMERICA
Canada, USA.
ASIA
Russia, India.
TYPES OF DIAMOND
 PINK DIAMOND
 WHITE DIAMOND
 WHITE WITH SECONDARY PINK COLOUR
 CHAMPAGNE DIAMOND
 YELLOW DIAMOND
 PINK DIAMOND
 BLUE DIAMOND
 GREEN DIAMOND.
PINK DIAMOND
•The pink diamond is the world's most rare and valuable
diamond.
•The Argyle mine is the world's foremost source of unrivalled
intense pink diamonds, producing 95% of the world's supply.
WHITE DIAMOND
•White diamonds are produced by mines all over the world in a
wide variety of shapes and sizes.
•The white diamonds recovered from the Argyle mine are
particularly brilliant and of high quality.
WHITE DIAMOND WITH SECONDARY PINK
COLOUR.
white diamond will display slight to bold flashes of pink
when viewed from the top.
CHAMPAGNE DIAMONDS
 Champagne diamonds are naturally coloured
diamonds that are produced in a wide range of
colours from light straw to rich cognac
YELLOW DIAMOND
 Fancy yellow diamonds come in a broad range of
shades ranging from light yellow colour.
 A limited quantity of fancy yellow diamonds is
recovered from the Argyle mine.
GREEN DIAMOND
A limited quantity of fancy green diamonds is recovered from the
Argyle mine.
The penetration of colour is not deep.
BLUE DIAMOND
Fancy blue diamonds are available in a wide range of shades,
from the blue of the sky to a more "steely" colour than
sapphire.
less number of this diamond is mined in argyle mines.
ARGYLE DIAMOND MINING
Key Data
Producer -- Diamonds
Location -- Kimberley, northeast Western Australia
Ownership -- Rio Tinto (100%)
Geology type -- Precambrian diamond-bearing lamproite pipe with
associated placer deposits
Mineral type -- Native diamonds
Reserve base -- 83Mt at 2.7ct/t hard-rock, plus 28Mt at 0.2ct/t alluvial
(2005)
Argyle diamond mine.
SOUTH AFRICAN DIAMOND MINING
DIAMOND IS MINED IN 3 PROVINCES IN SOUTH
AFRICA.
1.GAUTENG PROVINCE
2.LIMPOPO PROVINCE
3.KIMBERLEY.
4.LESTHOTHO.
The company that started mining there is DE BEER’S
COMPANY.
KIMBERELEY
GAUTENG AND LIMPOPO PROVINCE
LESTHOTHO
MAJOR DIAMOND MINING IN INDIA
 PANNA MINES
 GUNTUR
 CUDDAPAH
 KARNOOL etc.
INTERIORS OF PANNA MINES
DIAMOND PROJECTS IN INDIA
 DHARWAR PROJECT
 BUNDELKAND PROJECT
 BHANDARA PROJECT.
DIAMOND MINING LOCATIONS IN INDIA
TYPES OF DIAMOND MINING
 ALLUVIAL MINING
 PIPE MINING
PIPE MINING
 Pipe mining refers to the extraction of diamonds
from volcanic pipes.
 Typically, a very large area has to be covered. An
average of 250 tonnes of ore must be mined in order
to produce a one-carat gem quality polished
diamond.
 In most countries, a diamond pipe mine is
composed of kimberlite, or blue ground.
 After the diamond-bearing rock is brought to the
surface, it is then transported to a screening plant
where the diamonds are separated from the hostrock.
ALLUVIAL MINING
 This process involves the extraction of diamonds
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from riverbeds or ocean beaches.
Millions of years ago, at the time the diamond pipes
were formed, some diamonds were weathered out of
the pipes and carried great distances along rivers and
even into oceans.
A wall is built in beach to hold back the surf.
Up to 25 metres of sand is bulldozed aside to reach
the diamond-bearing level.
Once reached, the diamond-bearing earth is
removed and transported to screening plants
ALLUVIAL MINING
Screening Process
 Once a mining operation yields ore, the diamonds must
be sorted from the other materials.
 This process relies primarily on diamond's high density.
 An old but effective method is to use a washing pan, which
forces heavy minerals like diamond to the bottom and waste to
the top.
 Cones and cyclones use swirling heavy fluids mixed with
crushed ore to achieve density separations.
 With this process 99% of the waste in the ore removed.
Screening plant
 Further separations may use either a grease table or
an x-ray separator.
 Final separation and sorting is done by eye.
 Crushed ore is mixed with a muddy water
suspension, called puddle, and all is stirred by angled
rotating blades in the circular washing pan.
 Heavier minerals settle to the bottom and are pushed
toward an exit point, while lighter waste rises to the
top and overflows as a separate stream of material.
 The surface of diamond is highly unusual in that it
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resists being wetted by water but sticks readily to
grease.
Here, wet gravel washes across 3 inclined surfaces
covered with beeswax and paraffin.
Diamonds stick to the grease while wetted waste
minerals flow past.
The operator routinely scrapes the material that
adheres to the table into a grease pot, using a trowel.
The grease in the pot is melted and the diamonds are
removed in a strainer .
 More automated systems use a rotating grease belt
and craper.
 Cones (left) and cyclones (right) use heavymedia
separation.
 Diamond-bearing concentrate is mixed with a fluid
near the density of diamond.
 Separation occurs in cones and cyclones by swirling
the mixture at low and high velocities respectively.
 In the cone, rotational mixing permits lighter
minerals to float to the top and run out as overflow,
while diamonds and dense minerals sink to the
bottom and are sucked out by a compressed air
siphon.
 In the cyclone, fast rotation of the suspension drives
heavy minerals to the conical wall, where they sink to
the bottom and are extracted
 The float waste minerals are sucked from the center
of the vortex.
 Cyclones are about 99.999% efficient at
concentrating diamonds and similarly denseMinerals
from the original ore.
PROCESS DONE AFTER SEPARATING
DIAMOND
 CUTTING
 POLISHING
 VALUING
 CLARITY GRADINGS
 CARAT ANALYSIS.
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