Requesting direction from the Provincial People's Committee on the proposal to continue surveying to find the cause of subsidence in Chau Hong

On August 17, the People's Committee of Quy Hop district reported and asked for direction from the Provincial People's Committee and relevant departments and branches on solutions to handle the subsidence situation in Chau Hong commune.

This move took place after Quy Hop district had a meeting with the North Central Geological Federation to continue listening to the report on the cause of the subsidence in Chau Hong commune on August 15. This was the second time the meeting was held to listen to the report, but after the meeting, the leaders of Quy Hop district still did not accept the cause or the proposal to conduct a phase 2 survey proposed by the North Central Geological Federation.

Tin mine of Tan Hoang Khang Company. Photo: TH

At the meeting, the participants all agreed that the North Central Geological Federation had made great efforts in implementing the signed contract contents; had adhered to the approved task outline; had prepared documents, construction drawings, and reports explaining the survey results, determining the cause of subsidence in Chau Hong commune to ensure the assigned time and progress. The causes that the Geological Federation had identified, the District People's Committee did not have the expertise to specifically and scientifically evaluate.

“However, the causes that the Geological Federation has concluded, according to the assessment of the meeting participants and the District People's Committee, are not convincing, do not ensure objectivity according to the reality in Chau Hong commune in the past time, have not determined the subjective cause of groundwater subsidence, causing subsidence and drying of water wells specifically but only stated general causes. The results of determining the causes have not met the expectations of the District People's Committee as well as the people of Chau Hong commune", the report of the Quy Hop District People's Committee stated.

The North Central Geological Federation drills to find the cause of subsidence. Photo: TH

In addition, the North Central Geological Federation also proposed to carry out phase 2 of the survey project to determine the cause of subsidence. The plan in phase 2 proposed by the Federation includes a detailed outline, seeking comments from leading experts.

At the same time, wells were constructed to monitor groundwater dynamics, including: 4 wells, each about 50m deep in Na Hieng field, near Tan Hoang Khang Joint Stock Company's mine; 2 wells were constructed west of Duyen Hoang Company Ltd.'s mine (the mine has stopped exploitation), each about 60m deep, with the purpose of controlling and determining the characteristics of ancient flows (according to previous research documents). Checking the impact level of Duyen Hoang Company Ltd.'s mine on groundwater in the pressure layer in carbonate sedimentary rocks of Bac Son formation.

The Federation also proposed to add a water pumping project in the mine of Tan Hoang Khang Company Limited (using a high-capacity machine), combined with the results of groundwater monitoring of the above 6 wells, to determine the relationship between groundwater dynamics in the subsidence area with the mine of Tan Hoang Khang Joint Stock Company, the mine of Duyen Hoang Company Limited and the relationship between water in the subsidence area and ancient flow.

In addition, this unit also proposed a solution to supplement geophysical work (symmetrical electric cross-section measurement and symmetrical electric depth measurement) to establish an isobaric map of the Chau Hong valley floor and detect underground structures that drain water from Chau Hong valley to rivers in Quy Hop.

“However, after reviewing the proposed content, the District People's Committee found that implementing phase 2 of the project is not feasible, requires a huge amount of funding, and does not ensure safety,” said Mr. Tran Duc Loi - Permanent Vice Chairman of the People's Committee of Quy Hop District. Mr. Loi also chaired this meeting.

A sinkhole in a field in Chau Hong commune. Photo: TH

After this meeting, Mr. Loi sent a document requesting the Provincial People's Committee and the Chairman of the Provincial People's Committee to direct the indefinite suspension of pumping, exploiting and using groundwater by organizations and individuals in Chau Hong commune, including Tan Hoang Khang Joint Stock Company. Assign the Department of Natural Resources and Environment and the Department of Construction to periodically inspect and supervise the company's operations according to the exploitation design; Environmental impact assessment report approved by superiors; Whether the exploitation scope exceeds the licensed boundary or not. Because of these contents, the District People's Committee does not have qualified staff to inspect and supervise.

According to the leaders of Quy Hop district, up to now, the North Central Geological Federation has surveyed and determined the cause of the subsidence in Chau Hong commune and has prepared a report to submit to the District People's Committee. However, the capacity of officials and experts in various sectors is still limited, especially in the fields of geology and minerals, and they do not have enough expertise to assess the cause of subsidence, cracks in constructions, and dry wells. The District People's Committee has worked with the North Central Geological Federation to determine the cause, but there has not been a precise conclusion to reassure the people.

“The district respectfully requests the Provincial People's Committee to assign specialized departments and branches to appraise the report assessing the causes of subsidence in Chau Hong, Chau Tien, Lien Hop communes, Quy Hop district of the North Central Geological Federation. From there, there will be accurate conclusions to announce to the local people to feel secure, stabilize their lives and serve as a basis for payment according to the signed contract”, the report of Quy Hop District People's Committee stated.

After nearly 3 months of exploratory drilling with a contract cost of nearly 1 billion, the North Central Geological Federation has yet to find the specific cause of the subsidence. Photo: TH

In addition, Quy Hop district also asked for direction from the Provincial People's Committee and related departments and branches on the proposal to continue implementing the phase 2 project of the North Central Geological Federation because it believed that this would require a huge amount of money and would not ensure safety (for the water pumping project in the mine of Tan Hoang Khang Company Limited).