In what is an environmental world-first, a unique species of tree from India that can produce diesel fuel and other valuable by-products has been successfully planted on an area of disused mine-land outside the Copperbelt town of Chingola.

It’s the first stage of a $7.5 million project driven by Konkola Copper Mines (KCM), in partnership with land regeneration experts BetterWorld Energy Zambia. The project, which is being funded in partnership with donor agencies and other financial institutions, will see the planting of 400 000 of the trees over the next three years.

The disused mine-land consists of 700 hectares of overburden (waste rock) and tailings (also known as mine dumps) left over from the mining operations of Zambia Consolidated Copper Mines (ZCCM) in the 1990s, prior to privatisation. The land now belongs to KCM.

The trees are expected to produce around 2 ½ million litres a year

The trees are expected to produce some 2 ½ million litres of diesel fuel a year for use by KCM’s mining operations, as well as various high-value pharmaceutical biochemicals for export. It is expected to create approximately 2 000 jobs in the local community.

“This ambitious project is significant on three levels – environmental, social and economic,” says Anil Tripathi, who heads up the KCM department responsible for the project.

“Environmentally, we are taking unproductive land and making it productive; socially, we are creating much-needed local employment; and economically, we are creating a portfolio of products essential for mining, agriculture and industry.”

The tree at the heart of the project is the Pongamia tree, which is found in India and other parts of Asia. What characterises the tree is its unusual environmental and commercial properties.

Environmentally, it grows well in arid conditions of intense heat and sunlight, and will even take root in sandy or rocky soil. Its thick foliage provides shade that keeps the soil from drying out; and its roots infuse nitrogen back into the soil, producing rich nutrients.

Commercially, the pods (seeds) that grow on the tree can be harvested and treated to produce a range of useful products. These include fuel, flammable gas, charcoal substitute, organic fertiliser, natural pesticides and cattle-feed.

“Planting Pongamia trees on disused mine-land made sense on paper,” recalls Tripathi. “But it had never been done before in practice. So, we did a pilot project to test the survivability of the trees.”

The pilot project targeted a 4-hectare test plot on one of the tailings sites. A more hardy and fast-growing strain of the Pongamia – known as Elite Pongamia – was used. Some 2 000 trees were planted in November 2016. Just over half a year later, by mid-2017, more than 99% of the trees were still surviving, despite the harsh conditions at the site.

“This was an outstanding success, given that the common first-year survivability rates on similar sites are less than sixty percent,” says Tripathi.

A walk around the area shows that the trees have completely changed the nature and character of the tailings site.

What once had the desolate look of a barren lunar landscape is now pulsating with signs of life. The trees are growing steadily, their green leaves standing up well to the intense heat of the day. The tallest tree on the lot has already shot past the 2-metre mark. Here and there, the pods that will eventually produce the fuel and other products have already started appearing on branches. Insects and birds are starting to make an appearance. Wild rabbits show up in the mornings and evenings, leaving tracks in the ground. Other plants – including tomatoes – are starting to take root centimetres away from the Pongamia trees themselves, a sign of the increasing nutrient content of the soil.

“To further improve the quality of the soil, we’re going to fertilise it with water from a series of fish-farms that are being built around the planting area,” says Tripathi. “The natural waste from the fish produces water very high in nutrients. That can then be used as fertiliser.”

The first fish-farm is already under construction next to the pilot site. It is lined with an impermeable material to protect it from the soil of the tailings area. It will soon be filled with water, and stocked with small fish known as fingerlings.

“And of course, the fish will be a vital source of protein for the community,” says Tripathi. “When the project is at full strength, there will be at least a dozen fish-farms.”

Because of all the multiple economic activities involved in the project, employment is expected to be significant. Trees have to be planted and cared for; the fish-farms need to be constructed, monitored and maintained; the pods have to be harvested and processed into a range of downstream products – from diesel and charcoal briquettes to fertiliser and insecticide. The project is expected to create 350 full-time jobs, 650 seasonal jobs and 1 000 indirect jobs.

The commercial spin-offs are equally significant. The charcoal-substitute will help to prevent the deforestation that arises out of excessive burning of trees to make charcoal; the various by-products, such as fertiliser and pesticides, have great export potential; and KCM itself will be able to source a portion of its annual consumption of diesel fuel locally, instead of having to import it.

“Mine rehabilitation is usually a cost,” says Tripathi. “What this project shows is that rehabilitation can actually pay for itself – and generate an economic surplus too that benefits the mine and the community.”

BetterWorld Zambia sees the KCM project as the tip of a very large iceberg, because of the many tailings sites in Zambia – the potential in the Copperbelt alone is some 5 000 hectares, reckons its CEO, Benjamin Warr. “We’d like to think that this project could eventually spark a mini-revolution in mine rehabilitation, not just in Zambia, but globally too,” he says.

See also: Underground at Konkola Deep