Need tip on how to detect cavity under pond...

[kelvin.birden]

[size=medium]Hello...I have an advanced question for whoever knows. I have no knowledge of metal detectors and scan equipment.We are trying to find a man made cavity, a room, underground under a small pond or lake in finland. It is an old storage facility from around the beginning of the 20th century, and the area above it has been flooded. We know this only from romurs, and we have a few ponds to check approximately the same size.

The walls of the room are of concrete or stone, and the room can be empty, or contain ferrous or none-ferrous metals, or both.

We need tip on what equipment to use, to be able to produce a report valid as a pre-archeological scan survey, so that atcheologists can proceed to an excavation. So we need equipment that can produce solid proof. We need to rent and learn this equipment ourselves.

I have checked OMK Gepard ground radar, and minelabs CTX3030. But I dont know the results through water, and I dont know how deep they can detect.Any type of tip would be welcome. Thank you.

Please check the attached image for explanation.[/size]

[attachment 270048 question.jpg]

 

[KinTN]

I'm thinking youll want to go with the seismic/penetrating radar machines. Both work just fine in water (think offshore oil exploration). Its just a matter of finding the exact machine that is best for your purposes.

 

[ZOFCHAK]

That's a strange situation, but I don't really think that a metal detector would be of much use. Surface sonar and divers to confirm any man made structures would be much more useful in searching for something like that. I realize that the location is under the lake bottom, but there are probably visible signs of construction or settling that should appear unnatural conpared to the surrounding lake bottom.

 

[Goldstrike]

Drain the pond first. I have a 20,000 gallon swimming pool and it took about 24hrs to drain it with a small submersible pump. I'll come over and help you if I can have a share in the treasure!!!!!!!!!!!!!!!!!

 

[Water wizard]

I would try diving the site and inspecting it visually. If you think it looks man made pump out the water and you are in there. If the concrete has metal in it then an underwater detector like an Excalibur would pick up the metal, so you could dive with it when you are making the visual inspection. I have a dry suit that I dive with, and a pump that pumps 29 gallons per minute. It might take a couple of days to pump the lake out, but if the water isn't deep you would be surprised how quick it would go. It would cost a bit to get all the kit, and to pump it out, but if you think ther is gold or valuables it could be done.
The main thing is to be sure you're in the right place before you pump it dry, and that what you are hoping to find is worth a decent amount of money. It's hard to know if what you want is in the room before you go to the expense of pumping it dry, I guess that's the gamble.. Good luck

 

[Robert2300]

Drain the pond is what I was going to say. The site sounds
like it has GREAT POTENTIAL!
Robt2300

 

[BootyHunter]

Well if your archeologists over there are like ours over here just leave it unfound. Rotting in the ground is what they prefer