in a responsible manner
Water is linked to Nordkalk’s production, even though the limestone industry is not a big consumer of water in comparison with metals mining, which has processes requiring large quantities of water. Because limestone is used for water cleaning, any water relating to limestone processing is not dangerous to nature.
In quarries, water collects on the bottom as groundwater seeps in through cracks in the bedrock. Rain and melt water from nature also end up in the quarry. Thanks to the composition of limestone, this water is clean. Tytyri in Lohja in Finland and Miedzianka in Poland deliver water to the municipal water utilities.
If a quarry extends deeper than groundwater level, it can have an impact on groundwater levels in the surrounding environment. Many of Nordkalk’s quarries are shallow and do not affect the groundwater level.
In Lappeenranta in Finland, calcite and wollastonite are processed in a flotation plant that recycles its water. The amount of water circulating in the closed system is about six million cubic metres. The system includes sedimentation ponds, where the flotation sand, a useful by-product of the process, settles to the bottom, and cleared water is reused in the process.
Quarry water can be utilized for other purposes, too: At some of the plants, it is necessary to wash stones to remove clay, for example. Also yards and vehicle wheels are often washed, for the purpose of reducing dust emissions.
Nordkalk sites have Water Management Plans. The guiding principle in each quarry is to carry out operations with an absolute minimal negative impact on both the surface water and groundwater.
In Uddagården in Sweden, water basins for quarry water were equipped with curved pipes, through which water is run forward. This simple solution helps catch any possible oil leaks from the machines as the oil floating on the surface of water cannot travel with the water through the pipe.
Wellness efforts as part of the treatment of Klinthagen quarry
An arched bridge has been built for more trout to be able to play further up the Klinthagen creek.
Today, the lake in Klinthagen quarry holds about 2.5 million cubic metres of water. When the quarry is fully broken out and the lake completely filled, the lake will accommodate about five million cubic metres and be Gotland's deepest lake and the second largest lake in terms of volume after Lake Bästeträsk.
In the autumn of 2015 a two-kilometre-long ditch was built to dewater the northern and central part of the quarry. When the pit is broken out ditches will also be constructed to carry water to the pit exit point and onward to Klinthagen creek. The ditches create a self-regulating system with natural sedimentation of the water extraction.
From the exit point the water will be transported to an area of maximally active wetland vegetation for further cleaning of the water downstream from the Klinthagen quarry and into the creek. Any limestone particles, clay particles and nitrogen resulting from limestone quarrying are removed, so that the water is crystal clear and has the same concentration levels as the natural creek water.
Fish conservation efforts will be carried out in the creek, to promote spawning fish and other aquatic organisms. Spawning gravel has been deployed and ditches adjacent to the sea and farmland have been cleared. An arched bridge has been constructed under a minor road so that more trout will be able to spawn further up the creek. To promote the fry’s hatching period, small flows will be pumped out into the creek from April to midsummer. Information on how the trout’s spawning territories evolve over time, will be collected by counting the numbers of spawning pockets every autumn until two years after completion of quarrying.
Pure water is one of life’s essentials
Limestone-based products play an important role in water treatment, in the preparation of drinking water as well as in cleaning waste and process waters and treating natural waters.
Nordkalk is the leading limestone company on its home markets. We deliver essential raw materials to numerous industries, and our solutions contribute to clean air and water as well as productivity of agricultural land.