Yes, Bill, I've heard the one about the bat...

Another story I've remembered. Whe I was a coputer programmer with the Coal Board in the early seventies, following on from the Aberfan disaster there was a lot of effort, including legislation, going into making sure that the volumes of pit heaps didn't exceed a certain tonnage for their size (after which they became unstable).

We had written a program which could calculate this volume (using tellurometer readings) and we took it to a few pits to gauge its accuracy against known volumes. At one pit in Wales, we got a negative response to our new-fangled technology, as they were quite happy with their present system, thank you very much.

This consisted of an old bloke with a big sheet of hardboard, marked into squares, a bag of sand and a bottle of water. He would circle the pit heap, building up a sand model of it on the board and then, when he'd finished, he'd tip the sand off the board into another bag, weigh it and extrapolate the tonnage of the heap.

When we got the readings from the surveyors and ran them through our program, we reckoned he was about 2% out, when the legislation demanded 5%.

We went home.

Pete