Quarry Rehabilitation
There are enough examples in the world where quarries have been reconverted into gardens, labyrinths or a large theatre.
Everyone in the stone quarrying industry will agree that it is a Herculean task to obtain permission for quarrying as environmental concerns have to be addressed. A restoration plan has to be given along with details about funding for the same.
Natural stone quarrying involves majorly cutting and restoration as a possibility. Extra effort is needed to set right the visual impact as well.
Experts believe that as soon as the quarry is exhausted, nature gets back into form very soon. Human efforts are needed to convert it into useful spaces. There are enough examples in the world where quarries have been reconverted into gardens, labyrinths or a large theatre. The Braga Municipal Football stadium in Portugal was built in 2013 in a granite quarry in Monte Castro. It is known as ‘The Quarry’ as well.
Now, let us understand in totality about quarry rehabilitation.
What is Quarry Rehabilitation?
Quarry rehabilitation refers to activities required to ensure that quarry operations are closed in an environmentally and socially responsible manner. Renaturation, restoration, reclamation, and recultivation – all fall under this term. The unavoidable impacts of mining on the environment are repaired through this process.
What is the objective of quarry rehabilitation?
The quarries must have a sustainable post-quarrying land use and that is in the best interest of the environment and society. Quarry rehabilitation helps in achieving that.
Important aspects of quarry rehabilitation?
Environment and biodiversity conservation are the important aspects of quarry rehabilitation. It aims to ensure that extraction site operations and rehabilitation meet all applicable laws and regulations, make the exhausted site safe and stable for future land use, manage impacts, risks and future liabilities.
Quarry rehabilitation also promotes the evaluation of different options for future uses, balances the socio-economic and environmental considerations. The likely effects on biodiversity over different phases of quarry development, from site preparation and development, operation, rehabilitation and closure are studied.
This systematic approach ensures that mitigation is applied and where ever possible, opportunities are identified for enhancing biodiversity. Not just that, the financial requirements of the quarry closure, including rehabilitation-related activities are looked into.
How can quarry rehabilitation be achieved?
Proactively engaging with relevant stakeholders on quarry rehabilitation and sustainability will help. Biodiversity management plans must also be in place.
Assessing the level of stakeholder engagement to develop and execute a rehabilitation plan is important. Multi-stakeholder collaboration is also a must. A communication concept to be put in place according to local needs and embedded in the overall communication strategy of the country.
What are the different land uses of the exhausted quarry?
The different components of the mine such as pits, waste rock dumps and tailing dams may have different post-mining land-uses. These land-uses should consider the land capability of the rehabilitated areas and the level of management that will be required to maintain the land-uses. Rehabilitation objectives should be established in consultation with relevant government departments, local councils, landowners, etc.
What are the different aspects of any rehabilitation programme?
The long-term rehabilitation objectives may vary considerably at different sites. In all cases, the first objective will be to protect the safety and health of people living in areas around the site. Any rehabilitation programme could involve the following – Restoration of the area by attempting to replicate the pre-mining conditions, reclamation of the area so that the pre-mining land-use and ecological values can be re-established in similar conditions. Reclamation can refer to returning a low-maintenance native vegetation or re-establishing a land-use such as agriculture or forestry. Establishing a forest or wooded habitat on formerly marginal or degraded farmland could also be considered as reclamation. Developing the area so that it is returned to a use substantially different to that which existed prior to mining. This type of rehabilitation aims to achieve new landforms and land-uses, which bring about a greater overall community benefit than would occur if the former land-use was restored. Converting low conservation value areas in regions with intrinsically low productivity to a safe, stable and non-erodible condition.
When should the rehabilitation plan be thought of?
Whatever the final rehabilitation objective, rehabilitation plans should be drawn up as early as possible and be an integral part of the mining plan. The people or entities responsible for rehabilitation should be able to influence how the mine develops and operates. Rehabilitation should be undertaken progressively during the life of the mine, if possible. Progressive rehabilitation may achieve significant efficiencies in equipment use, earth moving costs and topsoil management. Sufficient personnel and resources must be allocated during mining to enable progressive rehabilitation without impeding production. Funding for final rehabilitation should be considered during mine planning and money budgeted while the mine is operating, as there may be insufficient income at the end of the mine’s life to cover final costs. If the mine has been operating for many years, it may be a more efficient use of capital and machinery to integrate rehabilitation with the final years of production.
What are the basic principles of rehabilitation?
The basic principles of rehabilitation that should always be followed are
• Develop clearly defined rehabilitation plans prior to the commencement of mining.
• Ensure the site is made safe.
• Always remove and retain topsoil for subsequent rehabilitation, except where it contains an unacceptably high number of seeds of undesirable species. Where possible, retain cleared vegetation for re-spread on disturbed areas.
• If the topsoil must be stockpiled seed the stockpiles with desirable post-mining species to discourage weeds and maintain soil microbial populations.
• Be aware of any statutory requirements and ensure these are met in the plan and the rehabilitation programme.
• If feasible, reinstate natural drainage patterns where they have been altered or impaired.
• Remove or control residual toxic materials. Identify potentially toxic overburden or exposed strata and screen with suitable material to prevent mobilisation of contaminants. Ensure the re-shaped land is formed to be inherently stable, adequately drained and suitable for the desired long-term land-use.
• Minimise any long-term visual impact by creating landforms, which are compatible with the adjacent landscape.
• Minimise erosion by wind and water both during and following the process of rehabilitation. • When mining is complete, remove all facilities and equipment from the site unless approval has been obtained
from the regulatory authorities and/or affected landholders to do otherwise. There may be occasions when post-mining uses such as tourism or heritage values require consideration.
• Compacted surfaces should be deep ripped to relieve compaction unless subsurface conditions dictate otherwise.
• Provided it is consistent with post mining land-use, re-vegetate the area with plant species that will control erosion, provide vegetative diversity and will, in time, contribute to a stable and compatible ecosystem.
• Prevent the introduction of noxious weeds and pests.
• Monitor and manage rehabilitated areas until they are self-sustaining or an end-point is reached which is satisfactory to the landowner, or the government instrumentality responsible for the land.
How to prepare the site for rehabilitation?
After planning, the first step in rehabilitation is to clean up and make the area to be rehabilitated, safe. This involves the following:
• Removal of infrastructure and unused or unwanted equipment. No facilities or equipment should remain on site unless with the written approval of the landowner or relevant authority.
• Removal of rubbish for disposal at approved sites. Care is required with residual toxic or hazardous materials including contaminated packaging and containers
• Removal of all services.
• Removal or burial of concrete slabs, footings, etc.
• Backfilling or securely and permanently covering any shafts, pits or similar excavations
• Restricting or preventing public access by removal or closure of access roads and tracks.
The step that follows next is to revegetate the area disturbed by mining and finally the rehabilitation programme must be monitored for its success or failure rate.
