is the Grootslang 'diamond prospector vanished' story real or made up for the blogs? (rating it)

every Grootslang page tells the SAME story word for word: British diamond guy, 1900s, name Peter Grayson, goes into the Richtersveld near the 'Wonder Hole,' his crew sees a giant snake-elephant thing and bolts, Grayson never comes out. cave's supposedly bottomless, full of diamonds, connects to the ……