Mining waste is an environmental time bomb and the industry its creator

The industry has consistently displayed a cavalier approach to safety when it comes to disposing of waste

The world mining industry always had an image problem relating to the hollowness of safety-first claim and poor corporate governance. The image was dented further and quite badly so in the past four years as a result of three major accidents. As it would happen all the three mine disasters took place in Brazil where crony capitalism has taken deep roots. In one of the worst tailings tragedies in history, a dam holding sludge of a mine owned by the world’s largest iron ore producer, Vale, in Minas Gerais state of Brazil collapsed on January 28 claiming a few hundred lives. The tragedy is a pointer to serious lapses in corporate governance since the company was warned last year that the dam had heightened risk of rupturing.

Earlier in November 2015, a tailings dam linked to a Brazilian mine jointly owned by Vale and Anglo-Australian BHP Billiton breached unleashing a tidal wave of about 40 million cubic metres of mining waste that killed 19 people and caused incalculable damage to a river and surrounding villages and acres and acres of farmland. Then  in February 2018, Brazil had to contend with another environmental crisis when toxic wastewater leaks at the world’s largest alumina refinery Alunorte owned by Norwegian Hydro following heavy rains poisoned drinking water and farmland in nearby plant areas. Alunorte suffered an identical crisis in 2009. The two wastewater leaks at Alunorte facilities were a wakeup call for New Delhi since the country has a growing profile in bauxite mining and refining of alumina. 

The fact is, what happened in Brazil could too occur elsewhere, including India unless a regular audit is done of the storage of mines and alumina refinery waste materials and corrective steps are taken without postponement that could harm the environment and people as dearly as in Brazil. Indian Bureau of Mines gives the message that management of a tailings dam, which is typically an earth-fill embankment dam, should be “an integral part of large-scale mining operations.” Safety apart, the mining sector in India suffered from many other ills, exposing the lack of effective corporate governance for the correction of which the Supreme Court had to make game-changing interventions in Karnataka, Odisha and Goa.

Bauxite is an important mining activity in India, which, after its processing into alumina, supports an annual white metal production of around 3.5 million tonnes (mt). Whatever the industry may say, unless the miners make foolproof arrangements of environment protection, the dust generated in the process of excavating bauxite will affect the health of workers and people in surrounding areas. Then, the leaching of bauxite in streams and rivers will do considerable harm to soil fertility and aquatic life.  Because of grievous injuries that bauxite could do to the environment, governments everywhere, under pressure from environmentalists and NGOs, are putting increasingly stringent conditions on the opening of new mines. 

What is of no less concern is the storage of highly alkaline red mud (RM) generated as a by-product in the Bayer process of extraction of alumina from bauxite by using a hot solution of caustic soda and lime. Depending on bauxite quality and refinery operational efficiency, anything between 1 and 1.5 tonnes of red mud containing six major oxides and several minerals is generated for every tonne of alumina. Because of its high alkanility and traces of toxic heavy metals, the disposal and storage of RM remain a massive challenge for alumina producers. 

RM is disposed of in ponds, lakes and streams after building a lining wall. Even then, a certain amount of seepage takes place, damaging soil in surrounding areas and all life forms. Embankment breaches and spill over from RM storage ponds during heavy rains always remain a possibility. As recently as August 2016, two villages in the Henan province of China were submerged in RM following the collapse of a waste pond dam. Here there was no human casualty, though a mass evacuation of people had to be undertaken and large tracts of farmland were covered in RM.  But when a similar accident happened at Ajka in Hungary in 2010, ten people died and a large number sustained severe chemical burns. 

The world is sitting on a pile of at least 3 billion tonnes (bt) of RM and is producing annually over 150 mt of the toxic alumina by-product. While alumina units will have to stay alert that embankment lining walls remain in good condition, every producing country should have a target for recycling of a certain percentage of RM. China, the world’s largest producer of alumina and aluminium, is chasing a target of 10 per cent recycling of RM a year. 

In an attempt to recover wealth from waste, Indian mines secretary Anil Mukim wants recovery of iron from RM. The Chinese aluminium maker Chalco is credited with finding ways to recover iron and rare earth metals from alumina by-product. RM contains 25 to 30 per cent iron. A few pilot projects to extract iron from RM are in operation and Mukim wants “such recovery to be made feasible on a commercial scale.” The twin goals are to find a solution to RM menace and create a new revenue stream for alumina makers. RM too could be used for making a host of building and construction materials, including cement and bricks.