Gemstone Mining

CountryDiamond Production in 2015 (in carats)Average Value Per Carat
Russia 41.9 million $101
Botswana 20.8 million $144
Dem. Rep. of Congo 16.0 million $8
Australia 13.6 million $23
Canada 11.7 million $144
Angola 9.0 million $131
South Africa 7.2 million $193
Zimbabwe 3.5 million $50
Namibia 2.1 million $591
Sierra Leone 500,000 $309

 World's Top Diamond Mines
ALROSA has 10 primary diamond mines, 10 alluvial mines, and 2 mines in development in Russia. ALROSA produced about 38 million carats in 2015. The company holds a 32.8% stake in the Catoca mine in Angola. ALROSA’s mines represent 8 out of the top 15 largest producing diamond mines in the world in terms of carats produced. Jubilee and Nyurbinskaya mines produced over 9 million carats in 2015 making them the fourth and fifth largest projects in the world.
1.) Jwaneng : Botswana. It is owned by Debswana. (50% DeBeers, 50% Botswana government) Jwaneng is the second largest diamond mine in Botswana and is nearing completion of the Cut-8 expansion, which will extend the mine life to at least 2025. Cut-8 will provide access to approximately 95 million carats of high quality diamonds, making Jwaneng the most valuable diamond reserve in the world. Jwaneng produced over 10.4 million carats of diamonds worth $1.6 billion in 2015.
>2.) Argyle : Australia. The Argyle mine in northwest Australia is owned and operated by Rio Tinto. The mine began production in 1985. The Argyle mine is known as the worlds largest producer of fancy coloured diamonds. It produced 12.6 million carats in 2014, making it the second largest diamond mine in the world in terms of carats produced. The recent move to full underground mining will extend the mine life to at least 2019.
3.) Orapa : Botswana. Orapa is Debswana-owned. Botswana’s Orapa mine was the worlds largest diamond mine in terms of total value of carats produced in 2014. Orapa is estimated to be the worlds largest by value, estimated to produce $1.9 billion worth of diamonds. In 2015 the Orapa mine produced about 11 million carats.
4.) Catoca : Angola. Catoca is owned and operated by Sociedade Mineira de Catoca, a joint venture of the state-run mining company Endiama (32.8%), Alrosa (32.8%), China Sonagol (18%), and Odebrecht Mining (16.4%). The mine went into production in 1997 and is expected to produce 60 million carats over its lifetime, about 35% of which are gem quality.
5.) Diavik : Canada. The mine is owned by a joint venture between the Harry Winston Diamond Corporation and Rio Tinto Group. The mine consists of three kimberlite pipes associated with the Lac de Gras kimberlite field and is located on an island 20 km2 (7.7 sq mi) in Lac de Gras. It is about 220 km (140 mi) south of the Arctic Circle. The Diavik Mine produced 6.1 million carats in 2015.
6.) Venetia : South Africa. The Venetia mine is owned and operated by De Beers. The open-pit mine began production in 1992 and now produces about 40% of South African total diamond production. The mine produced over 4 million carats in 2015 with production valued at over $500 million.

7. Ekati : Canada. The Ekati mine is 80%-owned by BHP Billiton. The open-pit mine began operations in 1998. The Diavik Mine reported 39.6 million carats of proven reserves and 13.7 million carats of probable reserves at the beginning of 2015. The current mine plan is expected to take the mine’s production to 2023. About 4 million carats were produced in 2015.
Gemfields Kagem Emerald Mine

The Kagem emerald mine is the world’s single largest producer of emeralds and accounts for approximately 20% of global emerald production.

It covers an area of approximately 41 square kilometres and is located in the central part of the Ndola Rural Emerald Restricted Area, in the Copperbelt Province of Zambia.
In 2004 Gemfields Resources PLC started systematic exploration south of the Ndola River, and made some important discoveries. Mining began in 2005. By 2007, Gemfields had acquired 100 percent ownership of two mines in the area.

In June 2008, Gemfields formed a collaboration with the Zambian government, establishing a 75/25 ownership split of the Kagem emerald mine.

Miners chisel the reaction zone rock to recover any emeralds it might contain.
Security and supervisory staff are always present during hand-chiseling of the exposed contact zone to recover the emeralds. This not only helps to secure the emeralds from theft but also helps to provide complete transparency of recovery.

Any production found goes into a locked production box.
Kagem is primarily an open-pit mine. Gemfields uses a strip-and-fill method to mine its deposits. A pushback occurs when they move the highwall of the pit farther back to continue exploiting the deposit.

The mine is expected to have another 25 years of life.
Once ore is transported to the washing plant, it follows a process that is typical of coloured gemstone mining operations. Screens are used to break down the material by size and then washers remove the silt to expose the potential emerald-bearing schist for hand pickers to examine.
Production capacity of the open-pit mine is around 8,000 tons of ore a month.

Cobbing removes highly included areas from the emerald rough.

Size classification is important since small stones are often less included than larger ones.

Sapphire Mining in Ilakaka-Sakaraha, Madagascar

A parcel of sapphire and chrysoberyl from the Ilakaka-Sakaraha deposit in southern Madagascar.
The Ilakaka-Sakaraha deposit in Madagascar is probably the world’s largest sapphire producer over the past 13 years.

The first discovery was in 1998, near Ilakaka Be. Locals quickly established a thriving market with Thai and Malagasy merchants. Within months, miners from around the island settled near the bridge on the Ilakaka River, and a boomtown was born.

Tourists regularly stop there, while Sri Lankan, Thai, and Malagasy gem traders still conduct business.
Ilakaka is a much quieter place today. The gem deposit extends about 120 km east from Anena to Anakondro, and nearly 100 km north from Anena to Antaralava.

In the Taheza basin the sapphire-rich gravels are usually about 30 meters deep, but some artisanal miners use a 50-meter vertical shaft to reach the gravels, which are mined by digging narrow horizontal tunnels. For the digger to breathe, air has to be sent underground using large plastic bags and tubes. The gravels are extracted and taken to the river for washing.
Overall, mining and trading around Ilakaka is down significantly from previous years. But with 10,000–20,000 miners and several hundred buyers, Ilakaka-Sakaraha probably still surpasses Ratnapura and Elahera in Sri Lanka as the world’s main source for blue and pink sapphires.

From April to July 2012, many of the buyers and miners left Ilakaka to work in the jungle near Didy and Ambatondrazaka, where fine rubies and sapphires were discovered in March 2012.
Montepuez ruby mine, Mozambique
The Montepuez ruby deposit is located in the northeast of Mozambique in the Cabo Delgado province. Covering approximately 33,600 hectares, it is the most significant recently discovered ruby deposit in the world.

The concession is located at a geologically critical junction between the north-south trending Mozambique Belt and the east-west trending Zambezi Belt. Both are “treasure-bearing” Neoproterozoic orogenic belts within the global Pan-African tectonic framework.

Estimates of probable ore reserves are 432 million carats at a diluted grade of 15.7 carats per tonne.
Gemfields PlC (LON:GEM) announced last year that Montepuez has enough reserves to last 21 years. Rubies are formed when fluid derived from the parental magma interacted with the host rocks under a silica unsaturated environment. After hundreds of millions years of erosion, rubies are liberated from the host rock and transported and concentrated by water and eventually settled in alluvial, colluvial, and eluvial deposits.
At its inaugural June 2014 auction of ruby and corundum Montepuez ruby achieved $33.5 million or an average $18.43 per carat with 92 percent sold by lot.

The auction saw 2.03 million carats of ruby and corundum placed on offer, of which 1.82 million carats were sold.
If this is the case, the stone could yield a cut and polished ruby with a wholesale value of $1.5 million or more. In November 2015 Gemfields discovered a 40.23-carat ruby at Montepuez which it has called “one of the most important rubies unearthed in recent times”

While the yield from the rough varies, one may assume 30 to 40 percent. This should provide a 12 to 16 carat gem. The question is how clean the stone is and if it requires heat treatment. A clean stone without heat treatment is more valuable.
The stone is significant because it attests to the mine’s ability to produce important rubies.

Due to the rarity of rubies, the discovery of a 40-carat ruby is comparable to finding a 100-carat rough diamond.
Yogo Gulch Sapphires
Yogo sapphires are a variety of corundum found only in Yogo Gulch, part of the Little Belt Mountains in Judith Basin County, Montana. Yogos are typically cornflower blue, a result of trace amounts of iron and titanium. They have high uniform clarity and maintain their brilliance under artificial light. Because Yogo sapphires occur within a vertically dipping resistive igneous dike, mining efforts have been sporadic and rarely profitable.
Gold was discovered at Yogo Creek in 1866, and though "blue pebbles" were noticed alongside gold in the stream alluvium by 1878, it was not until 1894 that the "blue pebbles" were recognized as sapphires.

Sapphire mining began in 1895 after a local rancher sent a cigar box of gems he had collected to an assay office, which in turn sent them to Tiffany's in New York, where an appraiser pronounced them "the finest precious gemstones ever found in the United States".
The Yogo dike is a narrow subvertical sheet-like igneous body. It varies from 2 to 26 feet (0.61 to 7.9 m) thick and extends for 5 miles (8.0 km), striking at an azimuth of 255°.

Montana sapphires were heavily mined during World War II for industrial abrasive and cutting purposes. In the early 1980s a scientific exploration concluded that the dike was at least 7,000 feet (2,100 m) deep and that the concentration of rough sapphires was not constant throughout the deposit.

Mining of Yogo sapphires remains difficult and is sporadic today. Even so, Yogo sapphire mining turned out to be more valuable than several gold strikes. The Yogo area also produced small amounts of silver, copper, and iron.

 There is hobby mining on small parcels at Sapphire Village, but commercial operations have ceased.

Ruby mines of Jegdalek
Just a few hours drive from the Afghan capital Kabul is an area renowned for some of the world's most valuable rubies.

Jegdalek mines have been worked for more than 700 years and are known for their high-grade blood-red rubies. The corundum deposit is hosted in calcite-dolomite marble and is up to 2,000m thick.
The deposit is worked by about 20 mines and more than 2,000 open pits and trenches.
The ore field includes skarns and muscovite-bearing pegmatites.The mines rarely produce the red rubies they were once famous for - more often than not semi-transparent pink sapphires are the only gems found, even at depths of 150m.

Every Friday the Taliban organizes a ruby bazaar near Jegdalek in the small village of Soar Naw - a remote and mountainous area covered with deeply forested valleys. Here they sell rubies which are then smuggled to Dubai, Pakistan and Thailand.
About 75% of the production at the Jegdalek mines is in the form of pink to violet-pink sapphire, with rubies accounting for 10%, and the balance being blue sapphire.

Greenland Ruby
Gemstones have been found in Greenland, including diamond, ruby, sapphire, kornerupine, tugtupite, lapis lazuli, amazonite, peridot, quartz, spinel, topaz, and tourmaline.
Most of Greenland's ruby and sapphire occurrences are located near the village of Fiskenaesset on the southwest coast.
A total of 31 ruby and sapphire occurrences have been confirmed in the Fiskenaesset district. The Aappattuloq Ruby project was being developed by True North Gems Inc. The company recently announced financial problems with the project being sold.
Ruby and pink sapphire rough has been recovered. The bulk of the material is rather small, with 90% (by weight) measuring less than a quarter inch (6.3mm). The quality of the rough raises hopes that Greenland Ruby might play an important role on the world gem markets in the future.

The largest gem facetted to date weighed 0.69cts and was evaluated at $ 2.100,00 (US wholesale).

In May 2011 an initial resource calculation was announced for Aappaluttoq. The resource included indicated resources of 189,150 tonnes of material hosting 59 million grams (296 million carats) of corundum and inferred a further 21 million grams (109 million carats) to a depth of 65m.

The resource is National Instrument 43-101 compliant and is the first coloured gemstone resource ever to be published under these laws.
The Belmont Emerald Mine
The hole diving 400 feet into the Belmont Mine is narrow, dripping wet and devoid of light. The waist-level elevator cage plunges quickly, and miners hold their arms close to their bodies for fear of losing them to the jagged rock walls of black biotitic schist.

The 25-year-old Belmont Mine is in an emerald-rich region called Itabira in the state of Minas Gerais, Brazil.
The mine is producing gem-quality emeralds consistently. Emeralds are a fairly recent discovery in Brazil.

The country’s geologists and independent miners long theorized emeralds must exist somewhere in Brazil, but the first deposits were not found until 1963 in the states of Piauí and Bahia.
Run-of-mine at Belmont is about 1,000 cubic meters of ore per month, or about 2,000 tons of emerald-bearing ore. Of that, about four grams per ton are gem quality.
The Belmont mine is reportedly one of the largest and best-developed mines in Brazil
Gemstones of Kenya
Kenya is famous for Tsavorite Garnet, and is also home to a host of other gems including amethyst, aquamarine, iolite, ruby and sapphire.

Ruby has been mined in Kenya for many years and a recent discovery near the town of Baringo in the Rift Valley is now providing the region with ruby and pink sapphires.
Tsavorite was first discovered in Kenya in 1970. The find was traced across the border into Kenya’s Tsavor National Park. It was later named Tsavorite by Tiffany’s in honour of the location of its discovery.

Since the 1970s there have been dozens of discoveries of small deposits along a 120 mile long belt, but none have turned into full scale mines.
Most of the Tsavorite mining takes place in south-east Kenya in areas such as the Taita Hills, Voi, Kasigau, Migama and Kuranze. All of these mines are worked by small groups and gangs with nothing more than the most basic hand mining tools.

In the Taita Hills to the west of the Tsavo National Park, there is currently a flurry of mining activity for tourmaline, with colours ranging from golden yellow through to vivid greens.
Towards the end of 2004, Kenya reported another amazing find of garnet. This time it was a colour change garnet. It looks a brownish green in daylight and a reddish pink when viewed under artificial light.

Little has been done by the government to regulate the industry. Cartels control the gemstone markets - and their agents buy up the gems and take them to Nairobi, making a huge profit.

Gems worth thousands change hands for as little as 150 Kenyan shillings ($2) on the black market.
Diamonds of Namibia
Diamonds have been mined in Namibia since 1908, when a railway worker found a stone that would change the course of history of Africa/Namibia.
The stone was a diamond, and shortly after he handed it to his supervisor, a frenzied diamond rush to the desert sands near Luderitz took place which resulted in the mining of seven million carats for colonial Germany until World War I in 1914.

Namibia is one of the world’s largest producers of gem quality diamonds, with about 95% of diamonds produced being gem quality.
Namibia is world-renowned for its gem quality placer diamonds that occur along the Orange River as well as onshore and offshore along the coastline. Namibian diamonds were originally transported via the Orange River into the Atlantic Ocean and distributed northwards by long-shore currents.

Diamonds typically occur as placers within raised and “drowned” beach terraces, gullies in the bedrock, and alluvial deposits in wind corridors within southern Namibia.
The major diamond producing company in Namibia is Namdeb Diamond Corporation, jointly owned by the Namibian government and De Beers, which produced 1.92 million carats in 2015, valued at $1.16 billion.

Other companies mining diamonds include Sakawe Mining Corporation (Samincor) and Diamond Fields Namibia.
Marine diamond mining began in the 1960s off the coast of southern Namibia. Namibia is the world's fifth largest diamond producer by value with an average per carat value of US$276.

Namibia's marine diamond production has now surpassed traditional land based production.
Marine mining as deep as 140m has brought Namibia the distinction of being the leading marine mineral mining country in the world. Over the years, the various areas combined have produced around 95 million carats, including around 12 million from deep water marine mining.

Diamonds continue to dominate Namibia's economy. They account for more than 40 percent of export revenue and more than five percent of GDP.
Amber Mining in Ukraine
The heart of Ukraine’s Wild West, thousands of acres of ravaged pine and birch forests whose sandy soils hide millions of dollars in amber. The rush is built by tens of thousands of poor villagers as they illegally blast apart the landscape with pressure hoses, digging for the brown lumps of fossilized tree resin.

When amber is mined on a large scale, the visible impact is industrial wasteland. Acres upon acres of forest are clear cut and backhoes are used to dig a channel to a water source—usually a river. Water pumps made of old Mercedes van engines blast into the ground. As the wildcatters pump water into the earth, deep pits form and the amber, lighter than the rocks and sand, is pushed up in the water column.
Thousands of hectares of land have been destroyed by the illegal mining of amber. The stakes are enormous. Illegal Chinese wholesale buyers in Kiev pay $ 4,800 for a rare 100-gram stone. An intact, 50-gram piece pays out $3,800. Even a 2-gram piece is worth $150. Chinese are paying about $2,000 to $3,000 per kilogram for big stones.

In a country where most people make around $2,100 a year the incentive is obvious.
Although there are a few government controlled mines, the process to get a license to operate a legal mine can take years and is fraught with corruption at every level. The estimated $500 million a year illegal amber mining business shows no signs of stopping soon.
Gem Mining of Taita-Taveta, Kenya
Taita–Taveta County is a county of Kenya. It lies approximately 200 km northwest of Mombasa and 360 km southeast of Nairobi. Taita Taveta County is endowed with vast mineral resources. The county is home to over 40 types of gemstones.

Some of the gemstones found in the area include tsavorite, red and green garnets, ruby, colour change, blue sapphire, pink sapphire, green tourmalines, yellow tourmalines, rhodolites and kyanites.
The vast wealth of Taita Taveta has not cascaded down to the rank of file of the region's 280,000-plus population. A majority of the ordinary residents live in relative poverty. The small artisan miners who are the main source of the gemstone production industry see only a tiny fraction of the revenue that the stones bring.

Color-change garnet from Kenya's Taita-Taveta region
Most gems are smuggled out of the country to waiting buyers, who then deliver them to the global markets for a fortune. Gemstone miners suffer greatly in pursuit of riches. So when they hit pay dirt, they go overboard and waste most of it on debauchery. A fool and his money parting company is often courtesy of the age-old twin catalysts - women and alcohol.
When the overnight millionaires go broke, it is not uncommon to spot them glumly sporting akala tire sandals and smoking cheap cigarettes as they search for the next windfall.
In Kenya, recycled tires become tough, inexpensive sandals called akalas.