you mention about 40 Kg gold it has small dimensions and as OKM claims their machines can detect an object which has 10 Cm x 10 Cm x 30 Cm dimension( ample of metal not hollow)maximum at 2 feet depth whereas can't even do this claimed job. No, no, don't waste your money for Localizer I haven't seen its' working, but have talked to one Localizer owner he was thorough unsatisfied and said it did nothing. Their machines just detect fields over ground though are good for finding cavities, but are very weak for metals. I have one Rover C and found some cavities/graves, one tunnel, but still no metal.
instead you can buy a powerful PI MD like as (Lorenz Deepmax, Pulse starII or new generations like as Genesis all are Germany made and good). Of course if the area surface is not huge cos some terrains searching are impossible by any of them.
Can I guess? Isn't your place in Middle East?
take a look at these addresses:
http://thunting.com/geotech/forums/s...ad.php?t=11994
http://thunting.com/geotech/forums/s...ad.php?t=11940