"I was so tired, I started slipping and my hands were sweaty and my arms were sweaty," he explained.
"[My co-workers] tried to pull me up but I knew that they weren't going to be able to, I just knew so I had to make a really hard decision, I just had to drop and see what happened with the safety line that was connected to my back."
And drop he did.
Mr Clay said he had expected his safety line to engage shortly afterwards, but nothing happened.
It was only then that he began to fear for his life.
"I started thinking about my family and my friends, and just thought to myself: well, is this going to be the end? And if it's not, what kind of state am I going to be in for the rest of my life?"