+CO Native Posted May 6, 2004 Share Posted May 6, 2004 I am finding that a lot of the benchmarks I am hunting have been covered and would like to give a metal detector a try. However I have never owned one and would like to know if they work very well for such a purpose. The ground here has a lot of granite which I am told has a high metal content to it. Will that make things difficult? One situation in particular has me wondering. The NGS marks I am looking for were on top of a mountain mounted in the rocks in 1934. Many large rocks have been flipped and moved and I have not been able to locate the benchmarks. The rocks are no more than 2 feet thick, but weigh enough that 2 people can't move them. Would a metal detector be able to get a reading through 2 feet of granite? If I get a reading on one rock that could be flipped back over I may try, but I'm not about to start flipping all the rocks in the area. What should I expect to spend? Quote Link to comment
Z15 Posted May 6, 2004 Share Posted May 6, 2004 (edited) I have a metal detector and have used them for many years. They would be of little help in what you have in mind. Any metal in the rock is going to give off a reading. To get the good ones (metal detectors) that can discriminate between metals you will be in the $500 to as much as $1000 area and then it will take some experience to find a small disk and not some beer can or vein of ore. (gold, silver etc ). Not Worth the cost and effort in my opinion. Edited May 6, 2004 by elcamino Quote Link to comment
+Kewaneh & Shark Posted May 6, 2004 Share Posted May 6, 2004 The metal locators that surveyors use to find monuments can be pricey, but even inexpensive models may be able to help you find some of the monuments you're looking for. It's doubtful however that they would pinpoint a mark under two feet of granite. Schonstedt Instrument Company makes many excellent survey-grade magnetic locators, if you'd like to compare them with other recreational metal detectors. I personally have a Schonstedt model GA-52Cx. A quick search for 'detector' in the benchmark forums showed these threads, among others. They might help answer some of your questions too. Need Advice For A Metal Detector For Bm Bench Mark Hunting And Metal Detectors, Locating old relics Useful metal detector, or just junk? Tools for Benchmark Hunting? Benchmark Hunting & Metal Detecting Metal detector? Using metal detectors - Kewaneh Quote Link to comment
Z15 Posted May 6, 2004 Share Posted May 6, 2004 fyi These survey disks are not magnetic! They are bronze, brass, aluminum or stainless steel and a Magnetic locator would be useless. Here is a LINK to some of the best discriminating locator made (IMO). Quote Link to comment
+SixDogTeam Posted May 6, 2004 Share Posted May 6, 2004 I hate it when I'm looking for a disc with my metal detector, and run into a stoopid vein of gold! Quote Link to comment
+geo_eclectic Posted May 7, 2004 Share Posted May 7, 2004 I dug into this subject (couldn't resist) back in October. Two points to keep in mind. One,You probably don't need to have a super sensitive detector when looking for BM's. How many BM's are more than 6 inches down? And, 3 or more inches across is pretty big in the metal detector world. Second, very sophisticated discrimination is not going to be much help. as elcamino said These survey disks are not magnetic! They are bronze, brass, aluminum or stainless steel and a Magnetic locator would be useless. and some of the non-magnetic disk are mounted on steel rods. The higher end general detectors are designed to work well in spite of any magnetic materials in the ground and to discriminate what type of metal it is. That is great if you are trying to find gold jewelry or lead musket ammunition. They also have the sensitivity to detect small objects (rings) fairly far down. You probably well be well served by a decent low end model. Just turn down the sensitivity and turn off discrimination. I ended up buying a brand name at about $100 which included headphones. Metal Detector Quote Link to comment
+ddnutzy Posted May 7, 2004 Share Posted May 7, 2004 Here in New England most of the bm's that are marked flush with ground are usually covered with leaves or mulch. Even a lot of the one's in ledge are covered. I always bring my detector on a search. I have a Whites Classic 3 that I set the discrimination fairly high to get less false signals from trash and the sensitivity on low unless the mark is undergound. Quote Link to comment
mloser Posted May 7, 2004 Share Posted May 7, 2004 I am also interested in a detector and would love to hear more of what you folks use! I am hoping that something cheap(er) will do me, as I already plan on buying a GPSr and digital cam. Quote Link to comment
2oldfarts (the rockhounders) Posted May 7, 2004 Share Posted May 7, 2004 We like cheap!! We have a 'Bounty Hunter Pioneer EX' that we got at Wally world for about $100. One suggestion that may help find benchmarks is to sweep another disk from the same time frame if possible and use the discriminate button to block any other type of metal. This way when the detector sounds off, you have already eliminated most of the 'junk'. You can also set the depth according to what the description says. Hope this helped. John Quote Link to comment
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