Toxic Spill at China-Owned Zambian Mine 30 Times Worse Than Estimated

The partial collapse of a waste dam at a Chinese state-owned copper mine in Zambia may have released 30 times more toxic sludge into the environment than previously reported, according to an independent evaluation of the disaster.

At least 1.5 million tons of the poisonous substance escaped when a reservoir failed at the Sino-Metals Leach Zambia Ltd. mine near the northern city of Kitwe, findings from the company hired to assess the environmental damage showed. That would fill more than 400 Olympic-sized pools and rank the incident among the mining industry’s worst catastrophes globally.

The government and the company have previously said 50,000 tons spilled in the February disaster. Video evidence from social media and field data show this to be “grossly inaccurate,” Drizit Zambia Ltd. — hired by Sino-Metals to conduct an environmental audit of the accident — said in a June 3 letter seen by Bloomberg and verified by the company.

Drizit described the event as a “large-scale environmental catastrophe” that threatened drinking water, fishing stocks and farmland in the area.

Sino-Metals questioned the methodology used by the company to assess the magnitude of the spill. It’s since terminated its contract with Drizit because of what it described as “contractual breaches.”

“The company was given time to remedy these breaches but failed,” it said in an emailed response to a request for comment. “Sino Metals was left with no option but to terminate the contract.”

The disaster risks undermining Zambian President Hakainde Hichilema’s plan to more than triple copper output to 3 million tons in the coming years. China Nonferrous Mining Corp., SML’s parent, in 2023 pledged to invest $1.3 billion to expand output in the southern African nation, the continent’s second-biggest producer of the metal.

The incident also complicates Lusaka’s ties with Beijing, at a time when Hichilema’s administration is working to conclude restructuring deals with Chinese lenders for about $5.6 billion of debt.

US Concern

The US Embassy flagged concern about the scale of the disaster last week, when it ordered the immediate withdrawal of its officials from Kitwe and some surrounding areas, citing newly available information that revealed the extent of the contamination.

In an Aug. 6 email to staff seen by Bloomberg and verified by the US government, US Ambassador to Zambia Michael Gonzales said the disaster appeared to be the sixth-worst in history, and that toxic substances including arsenic, cyanide and uranium will continue to pose threats to humans and animals until removed.

The US Embassy declined to comment.

The Finnish and Australian embassies both in recent days updated health warnings related to the disaster.

“Without immediate intervention, the consequences for future generations of Zambians will be severe and long-lasting,” Drizit said in the letter.

The company declined to comment beyond verifying the letter, citing legal reasons. Drizit’s parent company in South Africa has been in the environmental risk-mitigation industry since 1975.

The Zambian government is in the process of contracting a new company to conduct the environmental impact assessment, and Sino Metals will still pay for the entire process, the spokesman said.

“The dam where the tailings escaped from is still there and the amount of tailings that escaped can be ascertained by the volume of the dam,” a spokesman for the company said. “However, if Drizit were able to calculate the amount of spillage by using social media footage, that is quite interesting methodology.”

Mike Mposha, Zambia’s green economy and environment minister, declined to immediately comment.

Drinking Water

Zambia’s government last week played down concerns about the incident, saying there was no cause for panic and that water quality in the affected areas has been restored. Senior officials appeared on state media at the weekend drinking tap water from Kitwe to prove it was safe.

No deaths or confirmed cases of heavy metal poisoning have been reported, the government said.

The disaster unfolded when a dam wall breached after heavy rains on Feb. 18, releasing a torrent of sulphuric acid-bearing material used to extract copper into the nearby Mwambashi River.

Preliminary assessments showed the river measured a pH as low as 1, Collins Nzovu, Zambia’s water and sanitation minister, told lawmakers Feb. 21. Fluid with that level of acidity is strong enough to dissolve human bones.

Water from the Mwambashi flows into the Kafue River, which passes through one of Africa’s biggest national parks. Zambia’s capital, Lusaka, relies on the river for much of its water supply.

In the immediate aftermath of the incident, the government began dumping hundreds of tons of lime into the rivers to neutralize the acid, which had wiped out aquatic life for miles, along with crops growing alongside them.

While the acidity may have returned to normal, heavy metals pose a persistent threat, especially to the 800 individuals still living near the fallout zone, Drizit’s letter said.

Long-Term Effects

Transparency International Zambia called on the government to “act seriously and pointedly” in a manner that the situation’s severity merits.

“The toxic spill needs to be addressed holistically,” Maurice Nyambe, executive director at the advocacy group, said in response to a request for comment. “The government and polluter need to be seen to be considering all aspects of this pollution, including the long-term effects on human life, wildlife, eco-system and the environment.”

Drizit said its engagements with SML had been difficult.

“From the outset, they have actively sought to disrupt the assessment process and have made attempts to influence the outcomes of our findings,” it said. “SML has accused us of breaching the contract and has since terminated the agreement just days before its conclusion, seemingly with the intention of preventing our report from reaching the proper authorities.”

SML didn’t respond directly to the allegation, nor did it respond to questions on how Drizit breached its contract.