was exploited since Han dynasty, and managed by a particular bureau in Song. And the city had major coal reserves of the province. Local coaling began by the 1070s, according to a lyric of the then governor Su Shi. Copper smelting in this area supposedly started in the Three Kingdoms era. The city astride the old course of the Grand Canal had been through several transitory periods of prosperity, before the grain tribute system was abolished in 1855. It remained being economically backward in the 1940s for wars, and a few people engaged in industrial sectors. Later the CPC positioned the city as a region of coal mining and heavy industry. Its dominant sectors are machinery, energy and food production nowadays. The construction machinery manufacturer XCMG is the largest company based in Xuzhou. It was the world's tenth-largest construction equipment maker measured by 2011 revenues, and the third-largest based in China (after Sany and Zoomlion). Education Xuzhou was a regional centre for education, but two defunct institutions once chose their sites within the city: Provincial College of Kiangsu () and North China Theological Seminary. In the 1950s, the then Jiangsu Normal Academy relocated to the city in 1958, and the then Nanjing Medical College, Xuzhou was founded later, both survived the Great Leap Forward. In 1978, the then China Institute of Mining and Technology relocated to Xuzhou. Schools Xuzhou No.1 Middle School () Xuzhou No.2 Middle School () Xuzhou No.3 Middle School () Xuzhou Senior High School () Xuzhou No.5 Middle School Xuzhou No.36 Middle School () Xuzhou No.13 Middle School () Universities and colleges China University of Mining and Technology () Jiangsu Normal University () Xuzhou Medical University () Xuzhou Institute of Technology () People's Liberation Army Air Force Logistical College () Religion According to the local administrator's survey in 2014, around 4.76% of the population of Xuzhou, namely 0.46 million people belongs to organised religions. The largest groups being Protestants with 350,000 people, followed by Buddhists with 70,000 people. Xuzhou is deemed one of earlier Buddhist centres in China supposedly because the Emperor Ming of Han mentioned that the then Prince of Chu Liu Ying built a "temple for Buddha". The local Catholic activities were dominated by the French-Canadians of the Society of Jesus since the 1880s, and there were 73,932 adherents and seventeen churches in 1940. Cathedral of the Sacred Heart of Jesus, completed in 1910, is