(The reason posts on restoration ecology is coming thick and fast is because I have an exam on this subject tomorrow. Might as well blog and study at the same time!)
Minespoils are one of the most degraded bits of land to have been generated by human activity. Even nature thinks so. Why do I say that? Because if nature was to restore a minespoil at her own pace, it would take centuries for her to bring back a thriving ecosystem!
In this case, I think it’s fortunate that humans work on a much shorter time-table. Due to our ingenious ability to bring massive change in ecosystems in a short period of time, we can put it to good here use by restoring lands that have been heavily degraded by mining…
Before we get into the restoration part of this blog, it is a good idea to go back to the harmful effects of mining. I did mention a list in a previous blog, but here’s the short version of how minespoils are an ecological disaster that needs to be mitigated-
- The area is completely stripped of the topsoil.
- All forms of life are destroyed, and cannot be reestablished for centuries to come.
- The entire soil profile gets disturbed and reversed.
- After mining, the mining company either stuffs the open-pits with sand and mud of any kind or they leave it open. It is really of no use to anybody.
- The wastes generated from mining severely alters the chemical properties of the area.
In a lot of ways, mining is more dangerous to environmental degradation than deforestation and improper agricultural processes, simply because it has a much lower restoration potential.
That is why, the research on minespoils has been heavily invested in. A helping human hand will go a long way in bringing back a thriving ecosystem.
- The first step is common to all restoration projects: selection of the site and study of its ecological history. This helps us plan our process, come up with a timeline, distribute work and arrive at a target, reference ecosystem.
- Once this has been done, we have to level the land. This is the most important step to restoring a minespoil; it is rather unique to it. Leveling is required because a mined area has varying topography. For example, an open case mine would have a gaping hole right in the center. A mine on a hillslope may require what is called contour dikes; contours that create flat plains on the land and prevent erosion.
The process of leveling is subject to the type on mine and the local area characteristics.
- This process of leveling takes a few weeks. This time period is given for the added soil to settle down into their new place. You see, we cannot just dump soil as a whole into the mine-pit. Soils have pore spaces in them and with increasing pressure from the top, the air from these pore spaces escape. As a consequence, they get compacted. If today morning, you filled a pit with two buckets of soil and saw that the pit was full, come back again tomorrow morning and check again. The pit will only be half full.
- Therefore, it is important to allow the filled pit to settle down. Multiple layers of soil is added, instead of dumping soil as a whole. With each layer of soil, grasses are planted to keep the soil bound together and sturdy.
- Minespoils also have a very coarse grained substrate and very high stone content. As far as possible, the large unwanted wastes need to be removed before pursuing restoration.
- Soil, as I mentioned, is almost absent in the area. To overcome this, organic wastes from ponds and tanks are added to the area after leveling. This increases the Nitrogen content and promotes microbial activity. This is the first step to restarting an ecosystem.
- The area will also have very low moisture. Adding organic wastes increase water holding capacity of the soil, and improve the drainage characteristics.
- Organic wastes from pond are not only rich in organic matter. It also contains a variety of seeds that will germinate, now that is has sufficient air, nutrients, microbial activity and moisture. You see the ecosystem forming in your head?
- Pond silt is also great for our long-term goals. Because it is so nutrient rich, it can help prepare a layer of topsoil that is 30-50 cm thick!
- Our final step in the initiation of an ecosystem will be to harvest water from local sources. If the area has good rainfall, rainwater harvesting structures can be used. Otherwise, our restoration site can be connected to local waterways via channels.
As always, including local communities in the restoration process is crucial for its success. Their inputs and involvement helps us achieve one of our objectives; economically and socially uplifting the local communities.