Sludge dam collapse incident: Business 'promises one thing but does another'

(Baonghean.vn) - To be licensed to exploit tin minerals at Lan Toong mountain, Chau Thanh commune, Quy Hop district, Nghe Tinh Non-ferrous Metals Joint Stock Company committed to implementing many environmental protection solutions.

» Sludge dam collapse incident: Businesses do things haphazardly and carelessly

» Close-up of giant sludge dam broken in Nghe An

Commitment of tin business

The environmental impact assessment report and environmental improvement and restoration project of Nghe Tinh Nonferrous Metals Joint Stock Company were sent to the authorities on December 25, 2012. In the report, the enterprise described “perfect” solutions to “minimize negative impacts, prevent and respond to environmental incidents”.

Various documents, licenses, environmental impact reports... of Nghe Tinh Non-ferrous Metals Joint Stock Company. Photo: Nhat Lan

That is to develop measures to minimize the impact of wastewater (including domestic wastewater, production wastewater, and overflowing rainwater); measures to minimize solid waste pollution (including solid waste during construction, domestic waste, and hazardous waste); measures to minimize air pollution, etc.

As for production wastewater, the report describes that “wastewater after passing through the treatment plant, if discharged directly to the outside, will seriously affect the surrounding environment, especially turbidity and also contain sulfide minerals of Fe, Pb, Zn, Cu... Water from the treatment plant is collected, then filtered and 100% pumped back to supply the mineral water system without being discharged into the environment.

Panoramic view of the production area and sludge storage dam of Nghe Tinh Non-ferrous Metals Joint Stock Company on Lan Toong Mountain. Photo: Dao Tuan

The report also stated that two sludge reservoirs (dams) with a waste storage capacity of 521,536m3 will be built. As for the reservoir at the mining site, the dam will be 15m high, the dam surface will be 4m wide, with a ditch and a spillway built with rubble and cement grade 75. With a large waste storage capacity, all waste from the mine's operations will be retained. Wastewater will flow into the settling pond.

Here, most of the suspended solids in the water are deposited. After the project is completed, the mud and sand cannot fill the reservoir, so in the rainy season, the stream flow is not obstructed. In case of heavy rain, it will drain out the dam's spillway. And Nghe Tinh Non-ferrous Metals Joint Stock Company commits: "Water from the ore selection process will be led into the reservoir. Here, with the design of the reservoir as calculated, the wastewater has enough time to settle before being pumped back for reuse, and with the design of the dam, safety will be ensured...".

On January 5, 2013, the Provincial People's Committee issued Decision No. 50/QD-UBND.DC approving the Environmental Impact Assessment Report and the environmental improvement and restoration project for the Tin Mining and Processing Investment Project at Suoi Bac Tin Mine in Chau Hong and Chau Thanh Communes, Quy Hop District.

In Decision No. 50/QD-UBND.DC, the Provincial People's Committee also requires that "for environmental protection works, detailed design and construction of environmental treatment works must be carried out in accordance with the contents of the environmental impact assessment report and current regulations on construction investment"; for production wastewater "during the operation phase, all wastewater generated from ore processing activities must be circulated and re-supplied to the selection stage, and must not be discharged into the environment in any form"...

Elephant head, mouse tail

In reality, the production activities of Suoi Bac Tin Factory are very manual, and waste is discharged haphazardly. Waste is dumped from the tin screening area, through a shallow soil ditch lined with burlap bags, only a few dozen centimeters deep, then poured down small streams to flow into the dam. There are places on the mountainside where mud flows out into black, thick pools.

The sludge dam that broke on March 9, 2017 is an artificial lake located about 100m from the top of the mountain, with an area of ​​about 3000m2. Three sides of the dam almost lean against the cliff. The remaining side is filled with soil to form a small embankment.

At present, this dike is broken in the middle, has many cracks and large subsidence.

The soil on the dike was still loose, indicating that it had been built not long ago. There was no more wastewater on the dam, but there was still a lot of sludge, dark gray in color. From the sludge came a strong stench of sulfur.

Because the dam was made of weak soil and could not bear the load, the dam broke. Photo by Dao Tuan.

The head of Nghe An Environmental Protection Department - Mr. Ho Sy Dung - went to the scene of the broken sludge dam and confirmed: in terms of dam safety design, Nghe Tinh Non-ferrous Metals Joint Stock Company has not fulfilled its commitment in the approved environmental impact assessment report.

According to Mr. Dung, the reason for the dam collapse was because the dam body was made of water-soaked soil, so it was not strong enough to withstand the load, causing it to break, crack, and collapse. Mr. Dung said: “The design documents for the dam were reviewed by the Department of Industry and Trade. This department needs to re-examine it.”

Regarding the Department of Natural Resources and Environment, Mr. Dung said that the Department has temporarily suspended all production activities and requested businesses to focus resources on overcoming the situation. Specifically, it is necessary to build a dam with rubble and cement from the foot of the dam according to the approved basic design height. This must be done quickly to prevent sludge from continuing to overflow when there are floods. At the same time, it is necessary to check and dredge sludge accumulated in streams and mountain slopes.

Head of Nghe An Environmental Protection Department Ho Sy Dung said he had worked with the representative of the business that caused the incident and was preparing a report to send to the Provincial People's Committee. Photo: Nhat Lan.

In the long term, enterprises must strictly implement all environmental protection solutions according to their commitments. It is possible to consider moving the waste dump to a safe area, not on high mountains. Or, there must be a plan to move the tin ore to a suitable location for screening and convenient sludge collection. Enterprises are responsible for identifying and supporting people affected by the incident with local authorities.

The Head of Nghe An Environmental Protection Department said that he had worked with the Director of Nghe Tinh Non-ferrous Metals Joint Stock Company on March 12, 2017 and was making a quick report to send to the Provincial People's Committee and higher-level agencies.

Nhat Lan - Dao Tuan