A miner in Reddit was asked about the Mel’s Hole and this was his response:

“In interesting subject to say the least and perhaps something of an urban legend . You have to ask yourself is Mel’s hole story intended to create him wealth and notoriety from the public . People have claimed to have seen it yet unable to find it at a later date . There are pictures on the net that show what is supposed to be Mel’s hole . Those I have seen resemble the landscape I grew up with and were open mineshafts of around the late 19th century . He claims it at least 80,000 feet that is about 16 miles , and I would consider improbable of measuring without sophisticated measuring equipment done from directly over the centre of the hole . Almost certainly would act like a well draining water from the surrounding area into it , albeit could be a long way down . At the supposed depth at least The temperature would be about around 80 ° c enough to create steam from any moisture entering the hole that would naturally rise to the surface and have seen with my own eyes working as a miner coming up from just under 3000 ft . Could not be dug by humans at that depth as the temperature would be impossible to stand . Neither would the hole be dead perpendicular as if drilled with anything mechanicly tends to wander over distance due to differering rock structure and hardness . As someone who worked As a miner for five years , I consider it is purely an urban myth .“