The recent red mud spill in western Hungary, which forced hundreds of local dwellers out of their homes, contaminated the soil and decimated wildlife, has raised the concerns about bauxite mining projects in Vietnam.
Nguyen Dinh Hoe of the Vietnam Nature and Environment Protection Society spoke to Tuoi Tre about imminent risks of the red mud spill in Vietnam.
What do you think about the red mud catastrophe in Hungary?
I’m very interested in this subject. The Hungarian red mud spill is obviously a warning to Vietnam as two bauxite mining projects are underway in the Central Highlands. Hungary has a hundred-year history of bauxite mining, and the MAL alumina plant is a huge and experienced company. Their catastrophe told us not to be careless with red mud.
The Vietnamese bauxite mining companies have assured that the red mud will be buried carefully. But it does not mean it will be safe after 20-30 years. It should be noted that the highest content of pH in red mud is 13, which is around 1 million times higher than the safe level.
If a similar catastrophe happens in the Central Highlands, the red mud will flow into Dong Nai River, threatening the lives and health of tens of millions of people.
What are the geological characteristics of the Central Highlands that may affect the process of bauxite mining?
The Central Highlands bauxite is the remnants of the weathered laterite crust on basalt rock formed in millions of years, which is different from the sedimentary bauxite dispersed in the limestone layers in Ha Giang, Lang Son and southern China.
The Central Highlands bauxite is the hard skeleton of the weathered crust, and is an important part of the structure of highland terrain. Whether in the hills or anywhere else, the bauxite is located on high places of the terrain.
Huge reserves of bauxite are in Dak Nong province, which is located on the roof of the Central Highlands, where the water just flows away. This means water supplies are limited to production activities that need much water such as bauxite mining and alumina production, and erosion will surely cause intense damage to downstream areas. If the red mud spill catastrophe happens here, red mud will quickly spread to the lower basin and it will be very difficult to control.
So underway bauxite mining projects in the Central Highlands will create huge red-mud lakes?
Red mud is a by-product/waste that derives from the alumina producing industries. It is composed of a mixture of solid and metallic oxide-bearing impurities, and presents one of the aluminium industry's most important disposal problems.
The red color is caused by the oxidized iron present, which can make up to 60 percent of the mass of the red mud. In addition to iron, the other dominant particles include silica, unleached residual aluminium, and titanium oxide.
Red mud cannot be disposed of easily. In most countries where red mud is produced, it is pumped into holding ponds. Red mud presents a problem as it takes up land area and can neither be built on nor farmed, even when dry.
Toxicity should be related to the disposal method practised and there is always a possibility of (heavy) metals leaching if the appropriate actions are not followed.
It is estimated that around 1.5 tons of red mud will be made from 1 ton of alumina. A report says the 15-year Nhan Co project will create some 9 million cubic meters of red mud, and the Tan Rai project, 80-90 million cubic meters. So we will need huge disposal lakes to contain the red mud.
What do you expect Vietnam will do to prevent a similar catastrophe?
First of all, relevant authorities must closely keep an eye on the process of bauxite mining, particularly the red-mud disposal lakes. But they will also have to calculate how to bury the red mud in a permanent way.
I think the best way, as proposed by many scientists, is that after bauxite mining is done in the Central Highlands, the red mud should be relocated to Binh Thuan province. Because it would be less dangerous if the red mud leak into the sea.
Bauxite mining companies have assured absolute safety for red-mud lakes. What do you think?
I was told that the disposal lakes’ bed will be covered with a layer of clay and a layer of cloth. The lakes will be divided into several sections, with a dyke system to be built to prevent rainfall. The dried mud will be covered with a layer of water-proof cloth and then covered by a 1-meter layer of soil. I hope the lakes will be well-protected in the process of mining.
But what is next? As the red-mud lakes are buried permanently in the Central Highlands, no one can tell what will happen after the projects are finished and developers leave the construction sites. Huge red-mud lakes will lie on the high places, which are prone to landslides. It will be a threat to the Central Highlands’ environment and the lower section of the Dong Nai River.
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