The tin-mining enterprise whose broken tailing pond led to an overflow of toxic refuse and mass fish deaths in nearby waters has been found to be operating without proper prerequisite environmental papers.

The finding was announced on Wednesday by Nguyen Thuong Hien, head of the Vietnam Environment Administration and leader of a government delegation sent to inspect Suoi Bac Tin Mining Enterprise in north-central Nghe An Province.

Last Thursday evening, a tin ore tailing pond used by the enterprise gave way in the province’s Chau Thanh Commune, Quy Hop District, causing nearly 100 cubic meters of mud and leach residue to flow into a nearby stream, killing hundreds of fish in its path.

The pond was later found to be built with dirt and soil, contrary to an approved design which dictated that it be constructed from stone and cement.

The broken tailing pond was among several environmental protection items required by law for the legal operation of the enterprise.

Suoi Bac’s parent company, Nghe Tinh Ferrous Metal Company, was supposed to file for certification that such items had been completed before it could be allowed to commence mining activities.

However, the enterprise failed to provide the requisite papers during the recent inspection, despite having been mining tin in Nghe An for four years, Hien told Tuoi Tre (Youth) newspaper on Wednesday.

In a meeting earlier that day with officials from the Ministry of Industry and Trade and leaders of Nghe An Province, Nghe Tinh CEO Nguyen Dinh Due also admitted to lacking environmental papers for the company’s mining activities on Lan Toong Mountain, where the incident occurred.