coalfield in Dolnośląskie province, southwestern Poland, at the border of Poland with the Czech Republic and Germany. The Turoszów Coal Basin has an area of 52 square miles (135 square km), making it the largest lignite (brown coal) deposit in Lower Silesia. Two open-cast coal mines (Turów I and Turów II) and a thermoelectric power plant operate in the basin near the town of Bogatynia.