will stop shale oil extraction by 2040 at the latest. Environmental impact Wastes and land usage The mining and processing of about one billion tonnes of oil shale in Estonia has created about 360-370 million tonnes of solid waste. Combustion ashes are the largest component (200 million tonnes), followed by mining waste (90 million tonnes) and spent shale (mainly semi-coke, 70–80 million tonnes). In addition, approximately 73 million tonnes of graptolitic argillite as overlying deposit were mined and piled in waste heaps in the process of phosphorite–ore mining near Maardu in 1964–1991. The oil shale waste heaps pose a spontaneous ignition risk due to their remaining organic content. The waste material, particularly semi-coke, contains pollutants including sulphates, heavy metals, and polycyclic aromatic hydrocarbons (PAHs), some of which are toxic and carcinogenic. As a result of decades of mining activity, the topography of the oil shale region has changed; this includes a greater range of altitudes within the mined area. Former and current oil shale mines occupy about 1% of Estonia's territory. About or 15% of Ida-Viru County's territory is out of use due to open-pit mines and waste landfills; an additional has sunk or become unstable due to underground mining. Semi-coke heaps near Kohtla-Järve and Kiviõli cover more than and ash heaps near Narva cover more than . These heaps protruding from the flat landscape are regarded as landmarks and as monuments to the area's industrial heritage. There is less biodiversity within the mined area; in particular, the reclaimed and reforested areas have less biodiversity than the areas which have undergone a natural succession. Water usage and pollution Surface water flows into mines and accumulates along with groundwater. This water must be pumped out in order for mining to proceed. The water that is pumped from the mines and the coolant water used by oil shale-fired power stations combined exceeds 90% of all water used in Estonia. For each cubic meter of oil shale mined in Estonia, of water must be pumped from the mines, amounting to about that are pumped from mines annually. Groundwater comprises 64% of the water pumped from underground mines annually and 24% of that pumped from open-pit mines. This alters both the circulation and quality of the groundwater, lowers groundwater levels, and releases mine water into surface water bodies such as rivers and lakes. Mining activities have contributed to lower water levels in 24 out