"Ham ech" mining method causes quarry collapse, burying three workers

Authorities determine Anh Tuan Company Limited mined incorrectly, undercutting the mountain base, leading to a quarry landslide in Thanh Hoa that killed three workers.

Around 17h on 20/5, a landslide occurred at Anh Tuan Company Limited's quarry in Quy Long village, Cam Tu commune, Thanh Hoa province, burying three workers to death. The victims were from Gia Hoi commune, Lao Cai province. At the time of the accident, many laborers were working near the base of the mountain.

On 27/5, a representative from the Geology and Minerals Department under the Thanh Hoa Provincial Department of Agriculture and Environment announced that authorities had determined the company's mining operations deviated significantly from the approved design. In the central quarry area, the enterprise excavated from the bottom up, failing to cut benches according to regulations on height and slope angle. This method involved undercutting the mountain base, creating a dangerous "ham ech" formation.

This improper mining method was a primary cause of the landslide. Additionally, the company had not constructed a designated path for workers to ascend the mountain from elevation +80 to elevation +160. The mining area also contained many loose and overhanging rocks, posing a risk of further landslides and safety hazards.

All documents related to Anh Tuan Company's violations have been transferred to the investigative agency for handling. Following the accident, Nguyen Hoai Anh, Chairman of the Thanh Hoa Provincial People's Committee, ordered a complete halt to all mining activities at Anh Tuan Company's quarry for investigation. He also called for a comprehensive inspection of compliance with regulations on mineral exploitation, occupational safety, and environmental protection.

Rescue forces searched for the buried workers on the morning of 21/5. *Photo: Lam Son*

Previously, the initial report from the Cam Tu Commune People's Committee suggested that prolonged heavy rain destabilized the geological structure, leading to the landslide. However, specialized agencies later clarified that this was not the main cause, but primarily due to technical errors during mining operations.

Anh Tuan Company Limited's quarry was licensed by the Thanh Hoa Provincial People's Committee for exploitation starting in 2015. It covers an area of over 13,600 m2 with reserves of over 451,000 m3 of limestone, approved for open-pit mining with a term of 29 years.