DIAMOND MINING

CONTENTS

INTRODUCTIONIMPORTANT DIAMOND PRODUCING COUNTRIES

AND COMPANIES IN THE WORLD.TYPES OF DIAMOND.TYPES OF DIAMOND MININGMINERAL PROCESSING OF DIAMONDDIAMOND MINING IN INDIATYPES OF DIAMOND MININGCONCLUSION

INTRODUCTION

Diamond is a transparent gem made of carbonThe Diamond came from the Greek word

adamas which means unconquerableDiamond forms in the kimberlite pipes The formation of diamonds began very early in

the earth's historyThe 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 – CClass – Native MineralSub class – Non MetallicGroup – carbon

IMPORTANT DIAMOND PRODUCING COUNTRIES

AFRICA Angola, Botswana, South africa

AUSTRALIA

NORTH AMERICA Canada, USA.

ASIA Russia, India.

TYPES OF DIAMOND

PINK DIAMONDWHITE DIAMONDWHITE WITH SECONDARY PINK COLOURCHAMPAGNE DIAMONDYELLOW DIAMONDPINK DIAMONDBLUE DIAMONDGREEN 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 PROVINCE2.LIMPOPO PROVINCE3.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 MINESGUNTURCUDDAPAHKARNOOL etc.

INTERIORS OF PANNA MINES

DIAMOND PROJECTS IN INDIA

DHARWAR PROJECTBUNDELKAND PROJECTBHANDARA 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 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 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

CUTTINGPOLISHINGVALUING CLARITY GRADINGSCARAT ANALYSIS.

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