Huge open pits once mined for coal and metals are enjoying a sometimes fragrant, or even tasty, afterlife. DW looks at different ways old mines are being rehabilitated.
As coal phaseouts come into effect globally over the next decade, innovative ways to rejuvenate and repurpose scarred mining sites need to be found.
This has already begun to happen in some parts of the world, often in ways that not only benefit the environment and climate, they also taste and smell good.
East German mines turned lake district
Former East Germany was a coal mining powerhouse, but the industry collapsed after the fall of the Berlin Wall. Soon after, 25 open-pit lignite mines in the Lusatia region were transformed into recreational lakes. Spanning the states of Brandenburg and Saxony, water was fed into the former mines from several major rivers, including the Spree and Black Elster. Some 30,000 animal and plant species have since been drawn to the region, leading to an increase in biodiversity.
Lake Geierswalde and Lake Partwitz in particular have since become holiday hot spots. Lake Partwitz was built on an old lignite mine at Geierswalde, a village in Lower Lusatia, and was fully flooded in 2015. The clear turquoise color of the lake is a product of quicklime added to the waters to neutralize the acidity from the defunct mine. But while great for swimming and boating, little has been done for plant and animal life.
Meanwhile, grape varieties are thriving on the slopes of the former Meuro opencast mine that is now Lake Grossräschen in Brandenburg. Experts say the intensely acidic soils that are a feature of excavated sites can inhibit plant growth but are excellent for viticulture. Wine producers are currently making three white wines, a rosé, a red wine and a sparkling wine from grapes grown at the ex-mine.
Gold mine goes green
Meanwhile in New Zealand, an open-pit gold mine that was shut down in 2016 has been rehabilitated with a view to replicating the native ecosystem. More than half of the roughly 260-hectare (642.5 acre) site carved out of its surrounding hillside has been completely regreened as part of the Reefton Restoration Project — initiated and run by the mine company itself, Oceana Gold.
So far, around 800,000 seedlings, made up of beech and local manuka tree species, have been planted at the site, with an additional 200,000 to be grown in the new topsoil by the end of this year alone.
Lausitz: Rebirth of an industrial wasteland
Another 64,000 wetland plants will occupy the banks of a shallow lake. These wetlands are part of an effort to stabilize the former tailings dam and enrich the area with birdlife.
"To see the wetland plants do better than we originally thought they would and in a shorter time frame, and see species come and living amongst that, is really cool," said Megan Williams, Oceana Gold environmental advisor.
Reshaping and landscaping waste rock is also part of the effort to enhance biodiversity at the site that is now barely recognizable as the bare mine pit it was a decade before.
"You're going to be surprised by what you see," Williams said of the future visitors to the former mine. "Because it's not going to look like what it did in 2012."
Lavender brightens a dirty mine site — and provides jobs
In the US, mining companies are obliged to rehabilitate former surface pits, even if thousands simply lie abandoned because of the costs involved.
Due to the high chemical residue in exposed rock and soils, reforestation or greening of mine pits is difficult without shipping in new topsoil.
But in the vast coal mining region of West Virginia, one plant has flourished in the poor soils of former strip mines: lavender.
The drought-tolerant herb that is native to the dry, rocky soils around the Mediterranean Sea is being grown sustainably on former mining sites by the Appalachian Botanical Company, which processes the fragrant oil to create cosmetic and culinary products.
In West Virginia, reforestation is the most common means of rehabilitation but is expensive and time-consuming. "Growing lavender has the potential to rapidly accelerate reclamation," say the Appalachian lavender growers, who also note that their farms are chemical- and pesticide-free and require little water.
The lavender is also thick with honeybees, vital pollinators that help revive and maintain biodiversity on these depleted sites.
In addition to restoring former opencast mines, this lavender rejuvenation is also labor-intensive and provides jobs for coal industry workers cut loose amid the energy transition.
From fossil fuels to renewables
From Germany to China, solar farms are also proving a popular solution to dealing with defunct mines.
In the city of Cottbus, one of the man-made lakes in a long-abandoned Lusatia coal mine is set to become the site of the largest floating solar farm in Germany. Work is scheduled to start this year on the farm with 21 megawatts of peak power output.
Meanwhile, Slovenia's biggest solar power plant was completed last year in the mining region of Zasavje (central Sava region) using land where a coal power plant once stood.
And in the Inner Mongolia Autonomous Region of China, the Boortai opencast coal mine, which covered an area of near 200 square kilometers, has been repurposed with 1.12 million solar panels. It was reported that after efforts to regreen the whole site were unsuccessful, the solar installation was adopted as an alternative ecological means to rehabilitate the vast mine.
Solar panels now fill out the old pit along with vegetation that thrives under the modules, a dual-edged solution that is also economically sustainable.
While mine pit rehabilitation is most often costly and complex, such innovative transformation of these debilitated sites is set to increase as a global coal exit comes into effect.