Race for copper is fraught with pollution

Copper is in great demand today, as it is used in electric vehicles and digital technologies, and is treated on par with Lithium. The race for it has heated up. With it, the environmental problems in copper mining are also hitting headlines.

A Chinese-owned copper mine in Zambia, named Sino-Metals Leach Zambia, recently unleashed a disaster, spilling 50 million litres of acidic waste into the Mwambashi River due to damage in the embankment holding wastewater from the mining operation. The river is a tributary of the Kafue River, which in turn flows into the Zambezi River, the largest, longest and most important river in Zambia. It forms a crucial part of the Kafue River basin, where 12 million people reside, accounting for about 60% of the country’s total population of 20 million. The river provides drinking water to nearly 5 million people, including those in the capital, Lusaka.

The spill killed fish, destroyed crops, harmed livestock, and caused devastation to local livelihoods. Besides Sino-Metals, three more foreign companies have faced accusations of acid spills and discharging chemical waste into the Kafue River watershed. Rongxing Investments, another Chinese-owned company, is held accountable for acid spills and a worker fatality, leading to the arrest of its director. A third Chinese-owned company, Ozone Mine, is accused of discharging chemical waste, which has led to crop failures and waterborne diseases. A British firm, Moxico Resources in Zambia, is linked to a toxic spill in January 2025 that polluted water sources.

Zambia’s economy is dependent on copper mining, and the country aims to quadruple its copper production by 2031 to meet global demand for electric vehicles and mobile phones. Four spills in four months have sparked public outrage. Citing minimal accountability in previous incidents, environmental groups have called for the prosecution of the companies. 

Environment Minister Collins Nzovu has described it as a “serious environmental disaster” and blamed the companies for their lapses. The companies have apologised and are trying mitigation measures, such as cleaning up and applying lime to the affected portion of the waterway. Nevertheless, the water quality has not yet revived. The Kafue River, vital for irrigation, fishing and drinking water for millions, remains at risk. 

Experts believe that applying lime to the affected portion of the waterway can counter the effects of extreme acidity levels. But it cannot control other toxins and heavy metals. The presence of heavy metals in the river system poisons fish and marine life for years to come.

Some species may adapt to prevailing conditions, but this shift would be disastrous for biodiversity and people, who depend on fishing. Reports indicate that the affected people have not received adequate food and water, and the mine management has failed to keep its commitment to mitigate the hardship of the communities.

Wastewater discharge from mining waste and metallurgical slag deposits, as well as seepage from tailing plants, contaminates water bodies and the underground aquifer. The breaking of the embankment and the spilling of 50 million litres of acidic waste at Sino-Metals has the potential to cause catastrophic pollution.

What’s in wastewater?

Apart from inorganic chemicals like metals, acids, alkalis, cyanide, dissolved salts, and anions, wastewater also contains radiological contaminants like uranium and tritium from mine tailings. Bacteria, viruses and small organisms are also present in the wastewater. Although tailing storages are supposed to be water treatment facilities, they do not deal with toxins. Their ability to handle heavy metals, chemical substances, and microorganisms is limited. 

Treatment in the tailings is critical for protecting human health and the environment and is thus provided with surfactants, leaching agents, reagents, solvent extractants, and antioxidants. The facilities are equipped with a sedimentation basin to settle suspended particles. To make the treatment efficient, pH is adjusted, and coagulants are used. 

The precipitation of metals depends on their insolubility in alkaline conditions, which are provided by limestone or lime. If the pH ranges between 6 and 9, Cu, Mn, Fe and Zn precipitate quite well. For the precipitation of other metals, pH should be between 10 and 12. Sulphates can be removed from gypsum-saturated water, and precipitation is possible even when it is associated with highly soluble sodium and potassium sulphate.

Since Zambia is in China’s debt trap for an amount exceeding $4 billion so far, efforts to remediate toxic spills and protect the environment are undermined. Additionally, China has promised to invest $5 billion in copper mines until 2031, which will entangle Zambia in further debt. The government may have to prioritise economic interests over environmental and social concerns.

India’s copper story seems better, but not quite rosy. Copper is mined at Khetri (Rajasthan), Malanjkhand, Balaghat (Madhya Pradesh) and Singhbhum (Jharkhand) in mines operated by Hindustan Copper Ltd. Private companies operate a few other copper mines. Among the major instances of pollution standard violations, the National Green Tribunal in 2017, on allegations of groundwater contamination by HCL in Balaghat, ordered the supply of clean drinking water to the villages of Chhinditola, Suji, Bhorkheda, Bhimjori, and Khursipur.

Indian mines, in general, implement a dust-suppressing system, manage wastes properly, and take precautions when transporting wastes and ores responsibly. The National Mineral Policy and Environment (Protection) Act, 1986, has set standards for regulating these mines.  

(The author is a retired Principal Chief Conservator of Forests (Head of Forest Force), Karnataka)