I think he forgot the part where Dany used a lens (like a magnifying glass) to determine it was pyrite. Of course the euphoria of what we thought he found was big enough that I could see why you would want to forget the second part.

To answer your drilling question. The drill doesn't go straight down...it goes on an angle. That's why it takes more meters to go to depth.

Use this diagram for example. Picture a drill rig at the top of the triangle and drilling along the path of 'h'. The actual depth in the ground that the drill would go to is C2, 349m = true depth. The drill however would travel along h, which is much longer. That's why it's longer, and in this case they found VG at 449m (using your numbers) even though the drill only got to 349m.