The naturally occurring calcium cycle has been altered by human intervention. Calcium is predominantly extracted from limestone deposits to be utilised by many industrial processes. Purification of iron ore and aluminium, replacing asbestos brake linings and some coatings for electric cables, are some of these major uses of calcium. Furthermore, calcium is used within the household to maintain alkaline pH of swimming pools, counteracting acidic disinfectants and in the food production industry to produce bicarbonate soda, some wines and dough. 
With its widespread uses, a large volume of calcium must be obtained from mines and quarries to supply the high demand. As more limestone and water is removed from mines, underground stores of rock are often weakened making the ground more susceptible to sink holes. Sinkholes and mining both affect the presence of groundwater, potentially leading to a lower water table or altered pathways of flowing water. This may affect local ecosystems or farmland as the water supply is restricted. Additionally, the water that is released from mining areas will have higher concentrations of dissolved calcium.  This can either be released into oceans or absorbed by the soil. Whilst not always detrimental, it alters the natural calcium cycle which may have flow-on effects for ecosystems. Furthermore, water being pumped from mines increases the danger of downstream flooding whilst simultaneously decreasing the volume on water in upstream reservoirs such as marshes, ponds of wetlands  It is however important to note than limestone mining is comparatively less damaging than other mining process, with potential to restore the environment after the mine is no longer in use