Question: What did the Thuringian miners do to help the country where Kim Pyong-il's father was a citizen?

full_context: Document 1: Thuringia: Environmental damage in Thuringia has been reduced to a large extent after 1990. The condition of forests, rivers and air was improved by modernizing factories, houses (decline of coal heating) and cars, and contaminated areas such as the former Uranium surface mines around Ronneburg have been remediated. Today's environmental problems are the salination of the Werra river, caused by discharges of K+S salt mines around Unterbreizbach and overfertilisation in agriculture, damaging the soil and small rivers.
Document 2: Thuringia: The traditional energy supply of Thuringia is lignite, mined in the bordering Leipzig region. Since 2000, the importance of environmentally unfriendly lignite combustion has declined in favour of renewable energies, which reached an amount of 40% (in 2013), and more clean gas combustion, often carried out as Cogeneration in the municipal power stations. The most important forms of renewable energies are Wind power and Biomass, followed by Solar energy and Hydroelectricity. Furthermore, Thuringia hosts two big pumped storage stations: the Goldisthal Pumped Storage Station and the Hohenwarte Dam.
Document 3: Kim Jong-il: Soviet records show that Kim was born Yuri Irsenovich Kim () in 1941 in the village of Vyatskoye, near Khabarovsk, where his father, Kim Il-sung, commanded the 1st Battalion of the Soviet 88th Brigade, made up of Chinese and Korean exiles. Kim Jong-il's mother, Kim Jong-suk, was Kim Il-sung's first wife. Inside his family, he was nicknamed "Yura", while his younger brother Kim Man-il (born Alexander Irsenovich Kim) was nicknamed "Shura".
Document 4: Kim Jong-chul: Kim Jong-chul (born 25 September 1981), sometimes spelled Kim Jong Chol, is a son of former North Korean Supreme Leader Kim Jong-il. His younger brother is Kim Jong-un, now the leader of North Korea. His older half-brother was Kim Jong-nam, who was assassinated in February 2017.
Document 5: List of leaders of North Korea: At the end of World War II, Soviet Union occupied the northern half of Korea and in 1946 established the Provisional People's Committee for North Korea chaired by Kim Il-sung. On 9 September 1948, the DPRK was proclaimed, also led by Kim Il-sung.
Document 6: Korean War: The resultant South Korean government promulgated a national political constitution on 17 July 1948, and elected Syngman Rhee as President on 20 July 1948. The Republic of Korea (South Korea) was established on 15 August 1948. In the Russian Korean Zone of Occupation, the Soviet Union established a Communist North Korean government led by Kim Il-sung. President Rhee's régime excluded communists and leftists from southern politics. Disenfranchised, they headed for the hills, to prepare for guerrilla war against the US-sponsored ROK Government.
Document 7: Korean War: The resultant South Korean government promulgated a national political constitution on 17 July 1948, and elected Syngman Rhee as president on 20 July 1948. The Republic of Korea (South Korea) was established on 15 August 1948. In the Soviet Korean Zone of Occupation, the Soviet Union established a communist government led by Kim Il - sung.
Document 8: Kim Pyong-il: Kim Pyong-il (; born 10 August 1954) is the younger paternal half-brother of the former leader of North Korea, Kim Jong-il, and the only surviving son of former leader and president of North Korea Kim Il-sung. He is the current ambassador of North Korea to the Czech Republic.
Document 9: Thuringia: The GDP of Thuringia is below the national average, in line with the other former East German Lands. Until 2004, Thuringia was one of the weakest regions within the European Union. The accession of several new countries, the crisis in southern Europe and the sustained economic growth in Germany since 2005 has brought the Thuringian GDP close to the EU average since then. The high economic subsidies granted by the federal government and the EU after 1990 are being reduced gradually and will end around 2020.
Document 10: Thuringia: Mining was important in Thuringia since the later Middle Ages, especially within the mining towns of the Thuringian Forest such as Schmalkalden, Suhl and Ilmenau. Following the industrial revolution, the old iron, copper and silver mines declined because the competition from imported metal was too strong. On the other hand, the late 19th century brought new types of mines to Thuringia: the lignite surface mining around Meuselwitz near Altenburg in the east of the Land started in the 1870s, and two potash mining districts were established around 1900. These are the Südharzrevier in the north of the state, between Bischofferode in the west and Roßleben in the east with Sondershausen at its centre, and the Werrarevier on the Hessian border around Vacha and Bad Salzungen in the west. Together, they accounted for a significant part of the world's potash production in the mid-20th century. After the reunification, the Südharzrevier was abandoned, whereas K+S took over the mines in the Werrarevier. Between 1950 and 1990, uranium mining was also important to cover the Soviet Union's need for this metal. The centre was Ronneburg near Gera in eastern Thuringia and the operating company Wismut was under direct Soviet control.
Document 11: Kim Jong-un: Scarce information on Kim Jong - un's early life comes from North Korean defectors and people who have claimed to witness him abroad, such as during his school attendance in Switzerland. Some of the information has been conflicting and contradictory, perhaps confusing him with his brother, Kim Jong - chul, who also attended school in Switzerland around the same time. Nevertheless, there has been some consensus on information about his early life. North Korean authorities have stated that his birthdate is 8 January 1982, but South Korean intelligence officials believe the actual date is a year later. Former basketball star Dennis Rodman said that the birthdate is 8 January 1983 after meeting Kim in September 2013 in North Korea. Kim Jong - Un was the second of three children Ko Yong - hui bore to Kim Jong - il; his elder brother Kim Jong - chul was born in 1981, while his younger sister, Kim Yo - jong, is believed to have been born in 1987.
Document 12: Korean War: Korea was ruled by Imperial Japan from 1910 until the closing days of World War II. In August 1945, the Soviet Union declared war on Imperial Japan, as a result of an agreement with the United States, and liberated Korea north of the 38th parallel. U.S. forces subsequently moved into the south. By 1948, as a product of the Cold War between the Soviet Union and the United States, Korea was split into two regions, with separate governments. Both claimed to be the legitimate government of all of Korea, and neither accepted the border as permanent. The conflict escalated into open warfare when North Korean forces -- supported by the Soviet Union and China -- moved into the south on 25 June 1950. On 27 June, the United Nations Security Council authorized the formation and dispatch of UN forces to Korea to repel what was recognized as a North Korean invasion. Twenty - one countries of the United Nations eventually contributed to the UN force, with the United States providing 88% of the UN's military personnel.
Document 13: Korean War: Korea was ruled by Japan from 1910 until the closing days of World War II. In August 1945, the Soviet Union declared war on Japan and—by agreement with the United States—occupied Korea north of the 38th parallel. U.S. forces subsequently occupied the south and Japan surrendered. By 1948, two separate governments had been set up. Both governments claimed to be the legitimate government of Korea, and neither side accepted the border as permanent. The conflict escalated into open warfare when North Korean forces—supported by the Soviet Union and China—invaded South Korea on 25 June 1950. On that day, the United Nations Security Council recognized this North Korean act as invasion and called for an immediate ceasefire. On 27 June, the Security Council adopted S/RES/83: Complaint of aggression upon the Republic of Korea and decided the formation and dispatch of the UN Forces in Korea. Twenty-one countries of the United Nations eventually contributed to the defense of South Korea, with the United States providing 88% of the UN's military personnel.
Document 14: Thuringia: Health care in Thuringia is currently undergoing a concentration process. Many smaller hospitals in the rural towns are closing, whereas the bigger ones in centres like Jena and Erfurt get enlarged. Overall, there is an oversupply of hospital beds, caused by rationalisation processes in the German health care system, so that many smaller hospitals generate losses. On the other hand, there is a lack of family doctors, especially in rural regions with increased need of health care provision because of overageing.
Document 15: Kim Jong-nam: Kim Jong-nam was born 10 May 1971 in Pyongyang, North Korea, to Song Hye-rim, one of three women known to have had children with Kim Jong-il. Because Kim Jong-il aimed to keep his affair with Song a secret due to the disapproval of his father Kim Il-sung, he initially kept Jong-nam out of school, instead sending him to live with Song's older sister Song Hye-rang, who tutored him at home. North Korea Leadership Watch says he left North Korea to visit his grandmother in Moscow, Soviet Union, and spent his childhood at international schools in both Russia and Switzerland until returning to his home country in 1988.
ground_truth: uranium mining was also important to cover the Soviet Union's need for this metal
sub_queries: Kim Pyong-il >> father Answer: Kim Il-sung
Kim Il-sung >> country of citizenship Answer: Soviet Union
What did the Thuringian miners do to help Soviet Union ? Answer: uranium mining was also important to cover the Soviet Union's need for this metal