Diamond mining in northern Angola results in environmental disaster in southern Congo (DRC)

This content was first published on IGR – Italian Gemological Review no. 14 in 2022. The information provided here is therefore current as of the original publication date.

In July 2021, a tributary of the Congo River changes its color in the Kwilu region. The death toll is 12. Thousands of other people get very sick from gastrointestinal disorder and diarrhea. A sudden fish die-off. Agonizing hippos float to the surface. Water consumption is banned by authorities. Under accusation, the Angolan Catoca diamond company, located a few hundred kilometers further south, first denies but then a leak from the separation plant to the river network is admitted, though consisting of clay rocks only and not involving any heavy metals, according to the miner. However, the disaster certainly originated in North Angola where diamond mining is the only industrial activity. As Congo (DRC) launches a hydroelectric megaproject to boost mineral extraction the question is: can gem mining threaten the environmental balance? Certainly it can, as evidenced by the case IGR has highlighted.

From the perspective of physical geography, the northern Angolan province of Lunda (Norte e Sul) and the southern Congolese province of Kasai are neighboring territories sharing common characteristics, such as wet and dry savannas but primarily a complex catchment area made of Congo River tributaries. The Tshikapa, Chicapa in Portuguese, is a tributary of the Kasai river which originates in the region of Lunda Sul, crosses Angola to the North and defines the border with Congo (DRC) for about 40 km. It ends up in the Congolese Kasai territory.

On its Angolan course, the Tshikapa River crosses the city of Saurimo, which under the new direction of President Lourenço is destined to be a diamond industry hub, where a cutting manufacturing unit will operate from the first half of 2021. One of its tributaries runs alongside the Catoca mining plant, the world’s fifth largest diamond deposit by output value. The Angolan government has high expectations for this facility. Undergoing a period of rapid expansion, it is managed by a Russian-Angolan company (the giant ALROSA holds a 41% stake).

Water availability is an important factor in the management of any mining activity. Not surprisingly, heading north along the rich hydrographic basin, there are some minor mining sites exploiting mainly secondary diamond deposits. Also here the diamond gravels need to be separated using water.

The Tshikapa River runs between a space that belongs to two separate nations and have different economic set-ups. The availability of valuable mineral resources in the Angolan Lunda is conflicting with the economic situation of the Congolese Kasai border region, where livelihood is totally based on fishery and agricultural activities, enabled by the river basin’s extension and its environmental well-being.

The upstream events inevitably affect the economic condition as well as the ecological balance downstream. All of a sudden, on July 12, the color of the Tshikapa turns an ominous reddish. While it is true that satellite images taken in August 2021 demonstrably show such polluted reddish water, starting from the south near the Catoca mine’s ore processing facility, it is equally true that the same images the year before show the same thing. This indicates that mining processing tailings are clearly evident even though they are not necessarily toxic. Rather, the pollutant front appears much more visible as the drainage areas of the Catoca’s ore separation process expand during the weeks the disaster occurred¹.

It takes several days before the alarm is raised. In the meantime, the toxic substances released into the river system flow along the Tshikapa, densify 330 km north of Catoca mine in the Congolese cities Tshikapa and Ilebo and break into the Kasai catchment area, poisoning the river’s wildlife life as well as the coastal residents. Twelve people are reported dead.

The disaster is publicly revealed only when it is done. Both the Russian mining giant Alrosa and its Angolan partner Endiama announced that informing about the plant’s leak was not their duty and only acknowledged the disaster on August 23, following Reuters’ disclosure of satellite images which dispelled any doubt: the causes of the pollution were to be found in Angola.

The Congolese Minister of the Environment Ève Bazaiba, however, had not turned a blind eye. As early as the end of July, she explicitly blamed Catoca’s mining operation (Figure 3) and immediately demanded a reparation for the damage caused: «We are waiting for a compensation, they have admitted that a pollution was there. We are taking samples to find evidence». The results released by the Congolese agency CRREBaC, specialized in the study and management of river resources, have left no doubt: «We can say for sure that this pollution comes from heavy metals that entered the river and our concern is that it is going into the food chain… An unprecedented environmental disaster».

Did the accident occur at the Catoca diamond mine?

The Catoca open pit diamond exploitation area occupies 64 hectares and was employing about 2,000 people in 2020. It is considered a modern facility with a 200 meter mining depth that is planned to increase to 600 meters in 2034. The material is transported by means of bulldozers and dump trucks to two processing lines where the ore is crushed and then delivered to the autogenous grinding mill via a conveyor belt. Five different stages of particle sizing are used to sort the crushed ore. One of these, the dense medium separation (DMS), involves the use of Ferrosilicon (a blend consisting of mostly iron, silicon, titanium and aluminum) which is mixed with water to separate the denser kimberlite rock containing diamonds (denser) from the less dense kimberlite tailings. Variations in the manufacturing process of a reagent may result in a change in the hazardous impurities in the chemical. The diamonds are separated from the concentrate by froth flotation, separated and cleaned, and finally weighed.

At the end of each operation, the Fe-Si is recovered from the process stream using a magnetic separator and then recycled. The problem with this processing is that Fe-Si losses can occur due to friction, separation products, density changes, and changes in magnetic properties.

What happened in July 2021 in the processing facilities at the Angolan diamond mine? Are the metal leakage to be attributed to other diamond processing facilities?

An accurate assessment would be possible only if systematic water chemical testing had been carried out in a timely and appropriate manner, taking samples from multiple locations. At the moment just conjectures are possible, having the Catoca Mine top management only authorized an in-house investigation where any heavy metal discharge is denied, while the dam breakage at the mine’s washing water retention basin is admitted. By contrast, satellite surveys show that many Angolan mining sites have been spilling their polluting substances into the hydrographic system that goes up towards Congo. And this certainly didn’t only happen starting from just yesterday. Only that this time the effects were severe and immediate. At the moment it is not possible to determine the exact original contaminating area, even if it is sure that the whole matter is related to heavy metals used for the industrial separation of diamonds.

A fragile giant. The hydrographic system of Congo

The Democratic Republic of the Congo, with a population of 90 million people, is by far the largest country in central Africa. Symbolically, its history over the last few decades reproduces the classic model of African economies during the decolonization stage. All the elements are there: strict colonial subjugation (by Belgium) and independence in 1960, consequent institutional weakness, inconsistency of a national governance, financial weakness and widespread corruption, total dependency on mineral wealth exports. According to the classic pattern of African post-colonial independence process, in 1965 the country ended up in the hands of a military figure, Mobutu, who nationalized the economy and governed it as a personal fiefdom until 1997 with consequent stagnation rather than growth.

Subsequently, the Democratic Republic of the Congo plunged into a phase of conflicts involving five other African states as well as its own region of Kivu implicated into a civil war that still makes the situation in the eastern part of the country critical. The struggle is nothing more than a true international dispute, under the UN observation, to gain control over the rich deposits of diamonds, gold and coltan (indispensable to the hardware industry) that can be found in that territory.

These raw materials, together with oil and hydrocarbons, represent the core of Congo’s economic system and the key to the country’s planned development. But the mining sector must coexist with the farming activity which is fundamentally based on subsistence and which, together with fishing and livestock breeding, is crucial for the sustainment of three quarters of the country’s population. All of Congo’s resources – agricultural, mining and energy – are based on the exploitation of its rich river network.

At more than 4,700 kilometres, the Congo is Africa’s second-longest river after the Nile and the world’s second-largest river by volume after the Amazon (41,000 cubic metres per second are discharged). It rises in the equatorial high-lands, flows across Africa’s largest rain forest, and drains westward into the Atlantic. With its catchment area of 3.7 million square kilometres, its countless branching tributaries delivering fresh water, waterways and regional transportation canals in Central Africa, creating an extremely extended network of 25,000 kilometres, the river Congo is the crucial artery and the engine of Central Africa’s expectations for development. It is the heart of a gigantic ecosystem and the world’s greatest reserve of untapped hydro-power.

The INGA hydroelectric power plant megaproject, the driving force behind all mining activities

And it is exactly this energy potential that the Democratic Republic of the Congo is planning to exploit in order to boost and increase its highly water consuming mining industry, which is already predominant in Angola as well. The repayment that Congo is now asking to Angola as a compensation for the July water leakage contamination refers to a pollution event that could also be occurring within its borders, should the sought-after expansion of mining facilities in Central Africa come to be implemented.

As a matter of fact, when the market demand for raw materials becomes as much pressing as it is today and new mining projects are planned and backed by generous energy injections deriving from new hydropower dams, environmental risks are multiplied. In addition to the deterioration of water, it is inevitable that extensive deforestation will interfere with the functioning of the entire river system, accelerating the decline in rainfalls. A massive hydropower development is not a recent ambition. It dates back to the 1930s. INGA I, the first hydroelectric station, was built in 1972 (351 MW) and was able to guarantee enough electricity supplies as to develop the capital city of Kinshasa. The second plant, INGA 2 (1,424 MW), was intended to trigger the eastern Congo mining development, but the results were just disastrous as the electrical distribution network only came into existence five years after the power plant was commissioned, causing the deterioration of materials and reducing the output. The subsequent national debt resulting from the country’s inability to repay the costly international borrowings was even more critical.

Amidst skepticism, conditional support, hesitations and fears on the part of the world’s major banks, the INGA project is proceeding under an agreement with the Australian Fortescue Metals Grouped and with Chinese and Spanish groups. When fully operational, a production of 40,000 MW should be reached at a cost of between 50 and 60 billion dollars.

Central Africa. A developing region with plenty of diamonds and mines, little diversification and high ecological risks

The news of the North Angolan toxic leak has been covered by the international press, but the wave of concern seems to be waning. If we consider it as an isolated case, a simple frontier issue, some crucial aspects will be lost.

This is not a conflict of interests between countries with different concepts of how to promote their own development. There is actually a common feature regarding countries such as the Democratic Republic of the Congo, Angola, Mozambique and Tanzania. Alternative production processes are not successfully implemented by the economic governance of such countries as all of them are dependent on their mining industry, where diamonds play an important role along with many other gemstones found in these area, a region that in many cases is where they are sourced (rubies from Cabo Delgado in Mozambique, tanzanite from Arusha in Tanzania, Zambian emeralds from the Kafubu area).

The power generator to consolidate this mining specialization will be a huge hydroelectric project in Congo, which presents huge environmental risks and certainly is not based on those alternative sources that paint green the renewable sources of the western economies’ future scene.

On a regional scale, conflicts over the use of water resources among agriculture, industrial mining and power generation may arise. The case of the toxic leakage of Angolan mines is but a first example. Such an episode involving several countries entails international law issues and legal disputes among these countries.

Whether or not environmental damage can be prevented will depend on the level of technology and resources on the part of foreign controlled mining companies. Paradoxically, this will lead Central African countries to a further dependence related to environmental sustainability management. This will be added to the chronic and long established financial and technological dependency.

Notes:

¹ Thanks to the satellite imaging available today, land pattern changes are visible. In this particular case the blog of Dave Petley, Pro-Vice-Chancellor (Research and Innovation) at the University of Sheffield in the UK, provides a precise photographic commentary on the enlargement of a large plume of pollutant material that appeared on the downstream side of the outlet dam of the Catoca plant. The plume over the days enters the watercourse of the Tshikapa tributary.

Further references:

• Catoca: Expedição científica pretende confirmar a inexistência de metais pesados ao longo do rio Tchicapa que possam ter causado mortes na RDC (Url: https://www.portaldeangola.com/2021/09/19/catoca-expedicao-cientifica-pretende-confirmar-a-inexistencia-de-metais-pesados-ao-longo-do-rio-tchicapa-que-possam-ter-causado-mortes-na-rdc, retrieved on March 19th, 2022)
• Congo Basin Water Resources Research Centre (CRREBaC), Water Pollution Disaster in Tshikapa and Kasaï Rivers Identified in the CB-CIS, retrieved on March 19th, 2022
• Grand Inga dam Congo, the Democratic Republic of the Congo (Url: https://www.banktrack.org/project/grand_inga_dam/pdf, retrieved on March 5th, 2022)
• RDC: Les autorités congolaises pensent que la pollution de deux rivières viendrait d’une mine située en Angola (Url: https://www.business-humanrights.org/fr/dernières-actualités/rdc-les-autorités-congolaises-pensent-que-la-pollution-de-deux-rivières-viendrait-dune-mine-située-en-angola, retrieved on March 5th, 2022)
• The River Congo – Africa’s Sleeping Giant (Url: https://www.clingendael.org/sites/default/files/2017-11/The_River_Congo_Africas_Sleeping_Giant.pdf, retrieved on March 5th, 2022)
• Waanders, F.; Rabatho, J. Recovery of Heavy Minerals by Means of Ferrosilicon Dense Medium Separation Material, Hyperfine Interactions, vol. 161, pp 55-60, 2006

Article by Paolo Minieri, published on IGR – Rivista Italiana di Gemmologia #14, Spring 2022