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Mike Bullivant's Diary

Day 27: Extracting Gold

Mike extracting mercuryOnly two more programmes to go but some of us already have our sights set on home. Not me! For this fifth programme, I'm teamed up with Mikey L again. He's fun to work with, though you sometimes have to kick his arse to get things going! We have to extract gold from the gold-bearing rock that we brought down after our overnight stay in Programme 3. Luckily for us, we're given a huge lump of cinnabar, an ore of mercury from which we can make some mercury. We can then use this to form a mercury/gold amalgam, from which it's an easy enough process to recover the gold. At least, I think it is.

The first job is for Mikey to crush our gold-bearing ore into a fine powder; only then will it react with the mercury. Problem is that we have absolutely no idea how much gold is in the rock; it could be parts per million, or even parts per billion, as far as we know.

Mike with mercuryWhile Mikey does his strong-arm stuff on the rock, I set about heating the cinnabar up in a boiling tube. Before long, silvery mercury droplets start to distil over. It's not quite that straightforward, however. Mercury's a pretty nasty metal because inhaling its vapour is dangerous and even at room temperature, there'll be a lot of mercury vapour where we'll be working; it can't be avoided. Neither should mercury be allowed to come into contact with your skin, so we take all kinds of precautions to ensure that the risks are minimized.

It really is a beautiful transformation from pink/red ore to a silvery, liquid metal. It's just the kind of thing that used to fascinate me when I was at school, and that led to my interest in chemistry. Sadly, however, it's not the kind of thing that today's school students are likely to be exposed to as it's far too 'dangerous'.

By the end of Day 1, we have a little crushed, gold-bearing rock (what has Mikey been up to all day?) and enough mercury to have a decent stab at extracting some of the gold from it. Should be a pleasant, stress-free day tomorrow.

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Photo: Mike Bullivant
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