SapphiresA brief overview of sapphires and the mining techniques.
A Brief Introduction• Sapphires are precious stones.• Comes in many colors, Most commonly: blue, yellow, pink.• Variety of the mineral Corundum.• 9 Hardness.• Most commonly used in jewelry.• Other uses are in scientific instruments, high durability windows, wrist watch crystals, very thin electronic wafers.• Aluminum Oxide- trace elements of other minerals give it its color- iron, titanium, chromium, copper, magnesium.
The Logan SapphireOne of the largest Sapphires found. It was found in Sri Lanka. It is422.99 carats.
Locations of SapphiresSapphires can be found ina number of places. • Cambodia• Burma • China• Kashmir, India • Malawi• Sri Lanka • Nigeria• Thailand • Tanzania• Madagascar • Canada• United States • Czech Republic• Australia • Kenya• Vietnam • Laos• Colombia • Pakastan
Locations of Sapphires• Burmese and Kashmir are the most sought after• From 1970’s to 2000 Australia was the world’s largest producer of Sapphires• Madagascar is currently the world’s supplier of Sapphires• Sri Lanka has produced the most large sized stones.• Burma used to be one of the most desirable locations for Sapphires, but now few good Sapphires are being produced.• Kashmir Sapphires are know to be the highest quality stones, but most mining has stopped. Only sporadic mining is done.
Mining TechniquesTraditional Pit Mining:• An example of pit mining would be when a vertical shaft is dug by hand until they have they have reached gem level.• A makeshift bamboo crane is assembled.• The crane is used to bring up buckets of soil to be washed and sieved.• This method of mining is very dangerous and back-braking.• These types of mines tend to collapse or cave in because there is nothing supporting the walls of the pit.• Pit Mining is an inexpensive operation to run but it also doesn’t produce a large quantity of stones. Only a few men are required to operate the mine.
Mining TechniquesOpen Pit Mining:• Is a small operation.• An area is dug to gem level by machinery.• Usually about 10 feet down to start.• After the initial pit is dig everything else is done by hand in small sections and sieved.• This method does not produce a large amount of gemstones.
Mining TechniquesOpen Cast Mining:• The work is seasonal• This type of mining has to be done during the monsoon season, usually around May to September.• Large amounts of water is required to operate the hoses used to wash the soil.• A very large pit has to be dug.• They use a large rotating drum with pumps and hoses.• The soil is dug out with machinery and then placed on a rotating drum. The drum washes and separates the gravel.• The gems are removed from the pit and placed on a pulsating jig. The jig is used to separates the soil from the gems.• They try to minimize the environmental impact by refilling parts of the pit that have already been mined.• Gemstone production can vary greatly from day to day mostly depending on the area being dug.