Dear All,
Looking for Underground gold detector specially for the buried gold (coins, jewelry & gold bar etc,) expected quantity varies from 1/2 kilo to 10 kilo at the depth of 12 to 15 feet.
Required specifications (as per my littler knowledge)
1) 3D
2) Minimum depth 15 feet (if possible)
Please suggest me the best quality gold detector which fulfills my requirement
There is no such thing as a "3D" metal detector. That's a marketing gimmick. You can post process the signal to get a contoured graph rather than a straight line graph but the information is always misleading. It does look cool though.
To get the type of depth you desire you will be limited to a ground penetrating radar unit. Even then if the ground is mineralized or wet you won't be able to achieve that 15 foot depth. If you are searching in dry sand a good GPR should get you deeper than 15 foot.
The size of the object you are searching for is a significant factor. Coins jewelry etc. are going to have to be pretty shallow to show up. Figure a few inches. Considerably larger objects including gold bars etc. are not going to be detectable at 15 plus feet. The soil disturbance from digging a hole 15 foot deep to bury an item will show up if the conditions are right. Most pros using GPR at depth are looking for voids, signs of digging or tunnels. Those sort of features are much more likely to be detected by GPR.
For the depth you are searching in you will need a very low frequency radar unit. Around a 100 MHz or less antenna/unit is what you will be looking for. Any higher than that and you will lose depth quickly. The trade off is greater depth = lower sensitivity.
Cost is way high for an actual functioning 100Mhz unit. They start around $15,000 and go way up from there. An inexperienced operator will have a very difficult time getting any real value out of a pro machine. The learning curve is steep.
Professional GPR geolocating services begin around $3,000 a day for 18" deep pipes. Figure about 8-12 times that much for objects at depth if you can find an owner/operator that isn't already booked by mining companies.
GPR units are not "gold detectors". They can not discriminate between the objects they sense. They are good at defining different general signal densities but calculating depth is almost impossible unless the ground is homogenous (dry sand) and there is a known reference depth to a buried object of the same material you are looking for. That's why they are good at locating shallow surface disturbances like utility trenches. They are not very good at defining what substance they are detecting such as iron vs. copper pipes. Small objects don't show up well if they show up at all.
I cannot recommend any particular brand or model but I will caution that there are a lot of false and misleading claims made by many of the popular treasure hunting GPR resellers. Buyer beware.
Good Luck on your search.
