Sludge dam collapse incident: Businesses do things haphazardly and carelessly

(Baonghean.vn) - Only by witnessing the mining site, the filtration system, as well as the sludge dams on top of Lan Toong mountain, Chau Thanh commune, Quy Hop district, can one see the haphazard and sloppy work of Suoi Bac Tin Enterprise.

» Mass fish deaths after a tin waste tank burst in Quy Hop

Close-up of the dam

The location of the sludge dam of Suoi Bac Tin Factory (Nghe Tinh Non-ferrous Metal Joint Stock Company) is at an altitude of about 600m. One must pass two slopes, Xoan and Dai Ca, to reach the top of Lan Toong; then, it takes nearly an hour more to slide down the mountainside, pass the tin mining and screening area, the system of settling and filtering dams... to reach the location of the broken dam.

The sludge dam of the Non-ferrous Metal Joint Stock Company on Lan Toong Mountain broke on March 9, 2017. Photo: Nhat Lan..

Right from the moment we passed the tin screening sites and the water filtration dam system, we could see that the mining method of Suoi Bac Tin Factory was very manual and not sustainable at all. And the wastewater and sludge discharge system was very arbitrary. The discharge system was poured from the tin screening site, through a few dozen centimeters of burlap-lined earthen ditch, then poured down small crevices to flow into the dam. The earthen ditch and crevices were covered with mud. There were places on the mountainside where clumps of thick black mud appeared.

"Pipeline" leads sludge from the tin screening area down to the dam. Photo: Dao Tuan.

Sludge is scattered in many places, from streams to mountainsides. Photo: Nhat Lan.

The broken sludge dam is an artificial pit located precariously only about 100m from the mountain top, with an area of ​​about 3000m2. Almost 3 sides of the dam lean against the cliff; the remaining side is built with soil by the enterprise, like a small dike. And the current state of that dike is like it has just suffered a big earthquake, causing a large crack in the middle with a length of nearly 30m; at the same time, many cracks and large subsidence appear.

Because the entire soil in the dam is still loose, it can be determined that the enterprise has been working for a short time; the compaction was done incorrectly, so the load-bearing capacity and strength are poor. And this is the cause of the dam break. On the surface of the dam, there is no more wastewater but there is still quite a lot of sludge, which is gray-black in color. From the sludge comes a strong, unpleasant smell of sulfur.

Mr. Lo Van Thanh, an environmental officer of Chau Thanh commune, was one of the officers who followed the stream to discover the incident of the broken sludge dam. Thanh said: At 9:00 a.m. on March 9, from the mouth of the broken dam, sludge and wastewater continued to flow down the mountainside, into Bac stream and downstream.

Thanh said: “This way of manually building earth dams to contain waste sludge is extremely dangerous. Not to mention the risk of dam failure that can happen at any time, with no transport route from the high mountains, once the dam reaches its capacity, the company will take advantage of the weather to discharge sludge down the ravines and mountain slopes…”.

Businesses cannot justify

According to Report No. 01 dated March 10, 2017 of Nghe Tinh Non-ferrous Metals Joint Stock Company, in addition to being licensed for exploitation, they have a license to exploit water resources and a license to discharge wastewater into water sources issued by competent authorities. Regarding the discharge system, wastewater is used in a closed-loop form in the wastewater reservoir for sedimentation and filtration; wastewater is then discharged into the environment according to the granted license.

Also in the report, Nghe Tinh Non-ferrous Metals Joint Stock Company said that the length of the broken dam was only about 12m; the reason for the break was that there was an underground water vein under the foot of the dike; at the time of the incident, the water in the dam contained only about 100m.³.

Regarding environmental issues, “In the water flowing through Chau Thanh commune (after being filtered according to regulations), about 600m from the company's discharge point, there is a wastewater source flowing from Mai stream, according to the company's assessment, there is an exploitation unit in the vicinity”. And to fix the problem, the company stopped all production activities of the factory to serve the repair work...

Tin sludge is gray-black in color and smells of sulfur. Photo: Dao Tuan.

However, at the time we were at the site of the dam break, there were only a few officers, workers and an excavator from Suoi Bac Tin Enterprise doing the “troubleshooting”. The way they were doing it was to use an excavator to build a small dike that divided the dam in two. The inner part, after creating an additional dike, was to continue to contain the sludge and wastewater from the screening system. The outer part of the dam with the broken dike was left intact.

When asked about the official of Suoi Bac Tin Enterprise who is in charge of "fixing the problem", Mr. Nguyen Linh Toan, Deputy Director, he said that the dam construction is to prevent wastewater from leaking into the environment from above. As for the dam construction, it is carried out according to the approved plan and design...

The outer dike was broken, with large cracks and subsidence appearing. Photo: Nhat Lan.

With the plan to build a dike with weak load-bearing soil, how can it be able to contain a designed amount of sludge of over 10,000m3? Mr. Nguyen Linh Toan explained: "Now I don't dare to say it's an excuse, but the people's question is that the company specializes in discharging dirty water outside. Chau Hong and Chau Thanh communes also regularly check. In the design, the dike is built with solid reinforced soil. The incident was an unexpected incident...".

Head of Quy Hop Department of Natural Resources and Environment, Mr. Le Sy Hao discovered a "throat" for discharging sludge. Photo: Dao Tuan.

Also here, when asked about the incident and the construction of the sludge dam of the Non-ferrous Metal Joint Stock Company on Lan Toong mountain, Mr. Le Sy Hao - Head of the Department of Natural Resources and Environment of Quy Hop district said: "At the time when Quy Hop district and the provincial authorities made the record, it was determined that there were about 200m³The sludge has been spilled into the environment. But that is an approximate figure. The construction of the dam is too sketchy. With a dam like this, consequences can happen at any time..." Mr. Hao also affirmed that through on-site inspection, the Department of Natural Resources and Environment has reported the actual situation to the district leaders for handling measures...

Nam Huong River (section passing through Chau Cuong commune) has murky yellow water; on both banks, the mud is gray-black like tin waste mud. Photo: Nhat Lan

Having witnessed with our own eyes the mining, screening, dam system and waste discharge operation of Nghe Tinh Non-ferrous Metals Joint Stock Company on the top of Lan Toong mountain, we conclude that this is a haphazard and sloppy way of mining minerals.

These dams containing toxic sludge at an altitude of 600 - 700m are like "dirty bombs", constantly posing a threat to the ecosystem and environment; negatively impacting people's lives. And the dam collapse on March 9, 2017 is undeniable evidence./.

Nhat Lan - Dao Tuan