Almonty in full swing ahead of tungsten pipeline launch

Semi-autogenous mills grind crushed tungsten ore at Almonty Korea Tungsten Corp.’s (AKTC) Sangdong mine in Yeongwol, Gangwon Province. Courtesy of AKTC

By Ko Dong-hwan

• Published Sep 29, 2025 7:00 AM KST

Sangdong mine to produce strategic mineral for Korea, US

YEONGWOL COUNTY, Gangwon Province — The Sangdong mine in Yeongwol County, Gangwon Province, now owned and operated by Almonty Korea Tungsten Corp. (AKTC), was first discovered in 1916 during the Japanese colonial period.

The Japanese government developed tunnels at the mine to extract tungsten, a high-density mineral essential to defense, electronics, manufacturing and other industries. After World War II, the mine helped support Korea’s economy as a strategic mineral source. It closed in 1994, however, as cheaper Chinese tungsten began to dominate the global market, including in Korea.

The mine remained dormant until 2015, when Almonty Industries acquired Canada-based Woulfe Mining and took control of the site. After conducting drilling for sampling and feasibility tests, the company found that the mine contains some of the world's highest grade tungsten ore with enough volume to remain productive for 100 years.

AKTC began developing the mine the following year, opening first portal and accelerating the gallery development. It expanded tunnels in multiple directions to create a network encircling a layered reserve of potential tungsten ore.

On Sept. 15, tungsten ore and rock waste were piled outside the mine’s entrance. While the first phase of constructing the ore processing plant next to the mine is underway, with completion later this year, underground preparations for production have been completed. The plant, once completed, will treat and process newly excavated ore straight from the mine.

“Once Phase 1 production begins, we expect to mine around 640,000 tons per year on average. Phase 2, which expands the plant further, will begin immediately after completion of the first phase. Once Phase 2 expansion is completed, the processing plant overall will process 1.2 million tons per year. For now, we’re making this expansion step by step, so ore production will ramp up gradually as the work progresses,” Benjamin Byun, operations superintendent of AKTC, said at the mine.

The mine has two main galleries: Alfonse D, running along the south side of the ore reserve, currently stretches over 1.87 kilometers, while Monty B on the north side extends more than 2 kilometers. Production during the first three years will focus on Alfonse D before gradually moving to Monty B. Together, the galleries have already exceeded the company’s planned length of 3.8 kilometers, suggesting the underground is fully prepared for production.

“We assume the mine will produce ore in a volume five times more tungsten than we originally planned. Ore in this mine have a tungsten concentrate grade of 0.45 percent on average, which is very high on the global scale. The figure elsewhere in the world, like China, is 0.15 percent,” Byun said.

Old mine galleries still exist, sometimes crossing the new path AKTC has excavated. The company utilizes the old spaces as storage for explosives used for tunnel extension and infrastructure equipment for mine operation, as well as air circulation paths to bring in fresh air from outside.

The tunnel will be wide and tall enough for a 45-ton mine truck to drive through and carry excavated ore to the outside once first phase construction is complete. For now, the company keeps extending one of the galleries left by Korea Tungsten Company, a state-run firm that ran the mine from 1952 to 1994.

While tunneling is underway, the company is detonating explosives at the mine’s stope accesses two times every morning to keep preparing for the production.

The mine infrastructure includes power cables, water hoses and inflatable tubes to bring in outside air, all running along the tunnel’s side wall. A communication line on the tunnel’s ceiling enables LTE wireless connectivity courtesy of KT, and a separate power line running along the other side enables the daily blasts from outside the mine.

“Once our mineral production begins, explosives will be detonated at least 14 times every day, each at different stopes,” Byun said.

To keep the mine from collapsing, entire surfaces of the dug-out tunnels are sprayed with shotcrete, a mixture of concrete and steel fiber that hardens surfaces quickly. Mine Safety DX, a safety technology that uses the LTE network, allows the company to monitor the tunnel from outside in real-time. All mined-out areas are also backfilled with cemented paste to ensure stability inside the mine. An emergency chamber with a blinking light also remains in position for miners, containing supplies of drinking water and foods for weeks to survive.

“We actively use modern mine ventilation systems, AI (artificial intelligence)-based safety monitoring and 3D modeling technologies to ensure the safety of our workers,” Byun said.

Treating ore

Next to the mine, the processing plant is now under construction. The plant comprises three different facilities, each performing a different ore treatment stage, transforming them from large rocks to tungsten filaments as thin as a strand of hair. The facilities are connected via conveyor belts on which the processed ore is transported.

The first facility is the crushing plant, reducing the ore to pieces 10 centimeters or smaller. In the next stage, semi-autogenous grinding (SAG) further reduces the ore to 65 microns before sending it to the ball mill. The company uses grinding mills imported from Metso, a Finnish manufacturer of world-class ball mills, SAG mills and rods mills. After this stage, the refined ore undergoes a process called scheelite flotation to extract the tungsten. The final product is a concentrate containing 65 percent tungsten trioxide.

“Tungsten mining used to see the mineral’s recovery rate at 60 to 70 percent. Our treatment facilities will raise that figure to 85 percent,” said Kim Jong-beom, external affairs team manager at AKTC.

AKTC’s mineral recovery techniques, according to Kim, were transferred from the Korea Institute of Geoscience and Mineral Resources, a state-run research center under the Ministry of Science and ICT.

At the end of the facilities is a wastewater treatment section, a critical step in ensuring the company operates in an environmentally sustainable manner.

Key challenges for any mining business include manpower availability, safety concerns and commodity price fluctuation. AKTC said it has solved all three at Sangdong mine.

“We have a solid local workforce supported by structured training programs in local universities,” Byun said. Saekyung University in Yeongwol has collaborated with AKTC on new programs to train students for working at the mine. Engineers and other experts at the company sometimes will visit the schools to deliver lectures for the students.

Last November, Yeongwol County Mayor Choi Myeong-seo announced his plan to designate Sangdong mine and its stored minerals as the county’s key growth engines and named Saekyung University as a key school to train necessary workers.

AKTC, according to Byun, is also one of the leading mining companies across the world for employing women, regardless of nationality.

The company, to prevent the mine from facing bankruptcy like it did back in the 1990s, has introduced a hard floor price policy for long-term offtake trades.

“It protects our mine allowing for stable operations. Meanwhile, we can maintain full upside potential. These measures will allow us to operate stably in the long term,” Byun said.

AKTC has a pilot plant here that simulates the treatment facilities at a smaller scale. The company said the pilot plants saved them time and allowed them to deploy developed technologies to the actual plants.

“One of the reasons Korea Tungsten Company had closed the mine was because of the monopoly by Chinese tungsten. AKTC, with its technical advancement and strong capital, has revived the mine,” said Beatriz Rendo Andaluz, CEO Office Manager.