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  • ‘Guaqueros’ look for emeralds in the Rio Minero.
  • After the heavy rain, a landslide blocked the narrow mountain road. A Cunas Mine worker clears the route so we can continue our journey. (Photo courtesy: Lalta Keswani)
  • Miners on one of the lower levels. It is very strenuous work, and Cunas gives them 10 days off for every 20 days they work. (Photo courtesy: Lalta Keswani)
  • Stairs going down one of the tunnels in the Cunas Mine
  • Security is very important at the mines, which all have armed guards. These safeguard the Cunas Mine.
  • Entrance to the Green Power Mine in the Muzo district
  • View of the blue-roofed buildings at the Green Power Mine camp. The mine entrance is near the pile of black shale in the lower centre.
  • Discovered in May at Coscuez and named the ‘ÄRE Emerald’, this 25.97-ct rough gem is considered exceptional due to its size, colour saturation and clarity. (Photo courtesy: Fura Gems)
  • One side of the Coscuez mine, showing the black shale where tunnels have been dug into the mountain. The main tunnel entrance is at La Paz on the other side.

Colombia’s ‘green’ emerald mines

By Cynthia Unninayar


The emeralds of Colombia have earned the reputation as being the finest and most coveted in the world, but where and how are they mined? A recent visit to the emerald producing areas in this South American nation gives new meaning to the term ‘mine to market’, as the emerald is becoming ‘greener’ in many ways.


The violence and rivalries that had plagued Colombia’s emerald sector for decades are but a distant memory. Today, the government is joining with the industry to ensure best practices, while helping meet the needs of small-scale miners. It is also encouraging foreign investors who bring state-of-the-art technology and financing for large-scale gemstone mining in the region, and who can help improve life in the mining areas. 


A bit of geology

The nation’s emerald deposits are found in the Department of Boyacá, located in the Andean region in the Cordillera Oriental mountain range in central Colombia. Colombian emeralds are distributed along both borders (eastern and western) of the Eastern Cordillera sedimentary basin, and the gems from the two areas exhibit different types of mineralisation, due to their formation during different periods in geological history. Emeralds in the eastern side were created around 65 million years ago, while deposits in the western basin are younger, with ages around 38 to 32 million years ago.


The mining districts of Muzo, Coscuez, La Pita, Cunas and Peñas Blancas, among others are located on the western side, while Chivor, Gachalá and Macanal are in the eastern zone. Found in heavily faulted and folded sedimentary layers of mostly black shale, the green gems crystalise in a hexagonal pattern and owe their colour to the presence of chromium and vanadium. 


Coscuez Mine

Even before the day had dawned over Colombia’s capital city, I was among several intrepid adventurers who set out on a five-hour trip from Bogotá to visit the Coscuez Mine. The first couple of hours were on highways, but as we entered the mining region, travel was at a snail’s pace as our 4x4s jostled over narrow bumpy dirt roads that zigzagged through the incredibly lush verdant jungle.


An iconic mine, Coscuez has produced some of the world’s finest emeralds since its discovery in 1646. Over the centuries, it was mined in the traditional manner with no investment in geology or infrastructure. The main tunnel ran along a slope from 896 meters at the La Paz entrance up to 1251 meters at Sabore. Some 80 percent of the secondary tunnels have since been closed or are inaccessible due to high inside temperatures or unsafe conditions.


In January 2018, Dubai-based and Toronto-listed Fura Gems purchased 76 percent of Esmeracol, the previous owner of the Cosquez mine and holder of the Coscuez mining license that covers 0.47 square kilometres. Under the leadership of CEO Dev Shetty, Fura approached this new acquisition scientifically by making geological surveys and mapping existing tunnels. In March, it began its bulk sampling stage, digging 25 kilometres of tunnels through 10,000 tons of rock. Two months later, it discovered an exceptional 25.97-carat gem. Fura Gems has also made changes in the way the mine interacts with the local community.


“We aim to set a new precedent for best practices in the gemstone industry,” said Shetty, “by transforming current standards into the premiere example of an enterprise that is employee friendly, sustainability driven and community centred.”


“In the 10 months since our acquisition of Coscuez Mine, we have hired 270 local miners and have committed to working with 70 local suppliers,” added Rosey Perkins, manager of new projects and corporate communication. Among its community-oriented non-mine activities is support for a health clinic, bakery and sewing centre. And, because removing mine waste in an environmentally friendly manner is important, Fura just created a special washing plant that is run by women. The Fura team clearly wants to restore Coscuez to its former glory while being a real partner with the community.


Green Power Mine

The next morning, we headed to the Green Power Mine in the Muzo district. Along the way, we traversed the Rio Minero where dozens of ‘guaqueros’ (independent surface miners) were looking for emeralds that may have washed down into the river. We were told that with underground industrial mining, the amount of emeralds in the river has declined dramatically, thus affecting the livelihoods of these ‘guaqueros’.


Julio Lopez, manager and part owner of the Green Power Mine, explained that three years ago, a group came together to invest and explore for emeralds in this part of the Muzo district since their geological surveys indicated good potential for the green gems. The first two years were spent building the installations and tunnels, and the mine became operational 15 months ago. So far, the miners have tunnelled 212 metres into the mountain without finding any gems, but its geologists think that they will be found at around 250 metres. A relatively small-scale mine, it has nine employees who work from 7 AM to 12 PM and from 1 PM to 5 PM. They all live at the mine since it is an hour drive over the Rio Minero and small winding roads to reach the town of Muzo.


Several inches of water cover the tunnel floor, from the rains draining through the mountain. The black shale walls of the tunnel are wet and powdery, and merely touching them leaves thick black powder on our gloves. At the end, we meet the miners who are using jackhammers and explosives to continue lengthening the tunnel in their quest for the green gems.


Cunas Mine

Our third destination was the high-producing Cunas Mine, owned by Esmeraldas Santa Rosa. A large mining camp, employing 140 workers, Cunas is one of the largest mines in the area. At any one time, there are 70 miners who work shifts from 6 AM to 2 PM or from 2 PM to 10 PM. After the last shift, a security team goes through all the tunnels and inspects them for water and oxygen. Each miner also must carry a portable compressed air tank, which provides air for 40 to 90 minutes. The employees all work 20 days, and then have 10 days off.   


Entering the main tunnel is through a long staircase, which descends to an 800-metre tunnel covered with several inches of water. Ventilation tubes run the entire length and pumps keep the water from flooding the tunnel. At the end is a large circular shaft where a boxy lift takes miners down to other levels. At the active face, miners carefully chisel out the emeralds, which are then placed in a pouch and taken to the surface.


Esmeraldas Santa Rosa also takes corporate social responsibility seriously. Its social management plan is developed in three thematic areas: helping young people to continue studies in higher education; building lasting relationships with suppliers and distributors based on shared values; creating alliances with local populations for sustainable social development.


The rains and the welcome

As we prepared to leave Cunas in the late afternoon, the skies darkened and a storm approached. Rain fell in sheets. Nonetheless, we started off. Alas, a few minutes later, we could go no farther. The powerful rains had caused a landslide and the narrow road was blocked. We had no choice but to return to the mining camp.


In a show of solidarity and kindness, the manager of the camp, Bryan Martinez, arranged to give us dinner, and then shuffled people around in the miners’ quarters so that we could have a bed for the night. He said that they would clear the road in the morning after the storm had passed. Following breakfast, we continued on to Bogotá, thankful to the mine personnel who had been so welcoming at Cunas and at the other two mines, where emeralds are definitely ‘green’. (Photo courtesy: Cynthia Unninayar, unless otherwise specified)

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