I take a ton as a metric ton or tonne equal to 1000 kg weight.
mass of coal transported to a height of 180 meters in one hour
= 20 metric tons = 20,000 kg
Change in the potential energy of coal : m g h
= 20,000 kg * 9.81 m/sec² * 180 m = 35,316 kJoules
Power supplied by the electric engine = Energy supplied / time duration
= 35,316 kJ / 3600 sec = 9.81 kW
Power = 10 kW if g is taken as 10 m/sec²