In the 1990s, after Estonia regained independence, the country underwent a restructuring of the economy, causing the collapse of a large part of the heavy industry sector. This collapse led to a decrease in the consumption of electricity and thus a decrease in the need for the oil shale that was mined to produce it. Electricity and shale oil export to former Soviet markets largely ceased. Due to a decrease in demand, the Tammiku and Sompa mines closed in 1999 and those at Kohtla and Ahtme closed in 2001.
