The project of exhausted air heat extraction in Wenjiapo Mine in Shaanxi Province was jointly completed by Kcalin and Sinomine Boneng. In this project, waste air and waste heat devices are used to replace industrial boilers to achieve clean energy heating in the air shaft site, and the waste heat in the shaft is fully recycled, with obvious energy-saving and environmental benefits. The system uses 20 sets of exhaust air heat boxes and 8 sets of wellhead heating units. The project was completed in October 2017 and officially put into use.