Hetty's mine was first put into use in the mid-1870s. However, disaster struck on April 11, 1893 when a fire broke out 350 meters underground. The fire was able to spread rapidly due to the strong ventilation and the countless wooden supports. 63 miners were trapped like rats and did not survive the disaster. Their ages ranged from 14 to 61 years.
Exhausted
By 1923 the coal veins were exhausted, but Hetty remained as un upcast shaft for the group's other two mines, Ty Mawr and Lewis Merthyr. Coal mining was eventually stopped there in 1983.