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Saturday, March 12, 2011

Diving for gold

Kevin and Cliff and David in the photos - the crew out on the ice. Kevin and David dive under 5 feet of ice and Cliff looks after the gizmology on the surface. Awesome operation - low tech but very impressive. Two big problems to manage - temperature and pressure - from which flow a lot of others. All driven by various engines and pumps and a compressor.

Temperature - how to keep the diver warm. There's a 120 ft coiled copper tube acting as a heat exchange - water flows through it and is heated by a substantial gas flame inside the coil. The water flows down an insulated tube to the diver's suit and is directed to his sternum and gloves. They are working on regulating this under water - at the moment it is controlled by Cliff adjusting the water flow. If the control fails and the diver starts to burn - well, one of the suits allows the diver to disconnect, the other doesn't  - yet.

Pressure - if I understood it correctly - how to prevent the heat loss from the expansion of compressed gas freezing the moisture in the breathing regulator valves and other vital components of the divers' survival equipment. Way more tricky and they have several systems to help with this - basically trying to keep the pressure difference as small as possible and heating the compressed breathing air by keeping the supply line close to the hot water supply.

Then there's the problem of light under 5 feet of ice - there is a set of sealed beam car headlights that sits under the ice base and can be anchored with weights and they cut away the surface ice to get a smooth glassy window to let sunlight in as well. - not too difficult,

And there's safety if things go wrong. Kevin uses a 'bail bottle' of compressed air that allows him to disconnect from the compressor line and float free. However - there's always a however in risky ventures - he then has a whole new pressure differential freezing problem in his regulator.

And the sluice box...And moving the shed...

Lots of related stuff - absolutely fascinating - and yes, they find enough gold to make it worthwhile.

I'll check all of this with Kevin when I can catch up with him and correct as necessary. We came in off the ice because of the tsunami warning.

Have a look at the photos - I'll get them on to picasa as soon as I can and post a link. Probably tomorrow.