city, Irkutsk oblast (province), far eastern Russia, on the Trans-Siberian Railroad. Founded in 1772 as a station on the Great Siberian Post Road, the town developed as a chief mining centre of the Cheremkhovo bituminous coalfield, but in the 1960s it began a steady decline because of limited reserves and the availability of coal nearby at Tulun. Other industries include machine building and mica processing. Pop. (2000 est.) 69,100.