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The Earth has an abundance of stone and minerals buried deep down and for centuries we’ve been digging up these useful materials for building and industry. The legacy has left a country littered with mines and quarries, some operational, some not.
The Importance of Managing Quarries
A quarry is essentially an open-pit mine where the excavation of rock like chalk or sandstone, gravel, slate or sand occurs. Its presence can affect the environment in several ways, from dust settling on vegetation and hindering photosynthesis or dissolving in water and changing its chemical composition, to noise from blasts disturbing the biodiversity – and humans – who live in the area.
To reach the rock underneath, quarries can extend below the groundwater level; small amounts of groundwater need to be pumped out of the quarry to maintain a dry floor for operations. Water management programs ensure water is used responsibly at the site and comply with the many legal requirements governing its use.
It is important to manage the output of a quarry – not just the commercial yield but the wastage too. We rely on clean water for drinking, growing food and supporting diverse habitats. There are many ways in which water can become contaminated, including:
- Excavation operations utilizing water, e.g. hydraulic processes that extract china clay.
- Mineral washing and processing activities.
- Water removed from excavation, e.g. during dewatering (removal of water from solid material or soil by various methods, typically in sand and gravel quarries).
- Washing vehicles, work areas, and equipment to suppress dust.
Quarry Operations can Cause Water Pollution and Flooding
Water run-off from quarry operations may contain solids that could cause water pollution, smother aquatic life or cause flooding by blocking channels. It is therefore important to design a quarry well to prevent contaminated run-off from leaving the site. The amount of ground exposed should be minimized, as should the number of stockpiles used; it’s also important to screen or cover stockpiles, tips and mounds with vegetation or fences to prevent solids being washed or blown away.
Settlement ponds, tanks or lagoons can be used to collect run-off and suspended solid contaminants can be removed once they have settled. It’s important to consider that the pond must be big enough for the amount of water that will flow through it, whilst also stopping any discharge if it becomes contaminated.
All quarries must apply for a permit if they are to discharge water from settlement ponds into the public sewer, surface water or groundwater, and they must comply with it or face a fine or prison. The quality and quantity of all discharges must be measured, recorded and reported to the appropriate authorities in accordance with license and work plan requirements.
Groundwater and Surface Water Monitoring Programs
Groundwater and surface water monitoring programs aim to predict the potential effects and evaluate the real effects of quarrying on local water quality based on proven approaches and methods. It will involve taking samples of the discharge wastewater as well as samples of the receiving surface and groundwater, both upstream and downstream of the discharge point, and sediment samples from upstream and downstream of the discharge point before, during and after the life of the mine operation.
Water quality is measured in terms of physical and chemical parameters such as:
- toxicants (heavy metals, oil, and grease, organochlorines and phosphates, etc.)
- suspended solids
- dissolved oxygen.
Efficient Operation of Quarries can Minimize Environmental Impact
A well-designed monitoring program will aid the efficient operation of the quarry minimizing the impact on the environment. By analyzing biological markers like species richness and diversity, the presence of particular invertebrates is a useful indicator of the health of an aquatic ecosystem. While quarrying can change the nature and landscape – even when handled carefully – there are some benefits. They can be an ecological niche, home to species you no longer find in other places such as the Bee Eater, Eagle Owl, and Natter Jack Toad.
Quarries and mines are a source of pollution, and their output and the surrounding water must be closely monitored to ensure the health of the environment around it. They do have their negatives, but they are also part of our national heritage and an important reserve of biodiversity.