Prevention of Spontaneous Heating by Reducing Surface Fan Pressure - A Case Study

No. 5 Incline mine is one of the oldest mines of Singareni Collieries Company Limited. There are two seams namely Queen (top) seam and King seam. Of these King seam is extensively developed and partly depillared. A 300 HP fan (3 m diameter) is working at old return air shaft which is extended upto King seam. The top Queen seam is virgin on north side. Presently, this virgin property of top is being extracted by Iongwall method of mining named as Padmavathi Khani Project. After Padmavathi Khani Project came into operation another return air shaft upto Qeen seam was sunk and a 3 m diameter fan (Andrew Yule make) was installed exclusively to ventilate the Queen seam workings, i.e. Iongwall face and 6 numbers of road header faces. The fan was set to operate at -5º blade angle and developing 57 mm (w.g) pressure, delivering air quantity of 7200 m 3 /min. After 4 months of commissioning the new fan, traces of CO (about 300- 400 ppm) was detected in return air of Iongwall face in tail gate, which continued for some time. After evaluation of various reasons, it was surmised that CO was evolved due to the development of high suction in top seam by the newly installed fan. Fan blade angle was changed and CO in return airway was no longer traced. This paper deals with the method of practical application of fan characteristic curves for preventing the spontaneous heating in Padmavathi Khani Project of No. 5 incline colliery of Kothagudem area, Singareni Collieries Company Limited.