I went down a copper mine two years ago. We know it was worked in prehistoric times and their method was to soften the ore by lighting a fire of sticks against the workface and clubbing the softened material with stone hammers. I went into the shaft and followed until it was just a metre high and I couldn't understand how anyone could have worked it, by that method. (There's an account of the journey on my Line!!cast2.mp3, on the downloads page of my website, if anyone's interested). I didn't even reach the end of the shaft - and I had a good torch! Fear of a worse fate could have kept the men - or boys - underground.

In contrast the observatory I've found has a concave drystone 'front' and is obviously built for a single chair, or throne, with just enough room for someone to stand beside. This is not good evidence, but it does suggest, to me, that the metalworking society was highly stratified. There's been no excavation - so all is inference, at present.