Good hunt, Ron. Hey, isn't that date/mint mark wheat a key date for them? I thought I just heard that somewhere but haven't checked my book to see.
Funny you should mention the guy wanting you to find a pipe on his land. One of the guys in my circle of detectorists just did that for somebody. He asked my other friend if he wanted to go out there and hunt the old house after they found it. My friend (my main hunting partner) decided rather to hunt with me yesterday. I told him he should have jumped on that. I know I would have.
Yep, if the park is old enough and all the "easy" deep coin signals are gone, then time to dig the iffy/junky/one way ones, or at least if those are even gone (that's rare that those are all gone at my sites), then time to dig out all the junk and see what might be under it. That's why I chuckle when I hear people say their public sites are drying up. I could probably spend a life time just digging the one way/junk/iffy coin signals at my sites, let alone the interesting "junk" to see what those might be (like a gold ring, toke, odd old coin that reads lower, etc), and what might be underneath them even if they are junk. No advancements in technology are probably ever going to change that. Far as I know VLF technology will never be able to see under junk to what's directly beneath it due to the nature of the detection field, which stops and only sees the first shallowest thing it hits. You just can't control the magnetic field in any such way to get around that, no matter how far technology advances. It's the nature of the field being generated.
Some are getting excited about ground penetrating radar that might one day be put into a detector-sized unit and have resolution high enough to see coin/ring sized targets. A few problems with that that I think will never make it happen. First, the way I understand it the power they draw is beyond belief and requires a rather huge battery. Second, even the big/bulky super expensive stuff has problems with coin/ring sized resolution. Third, even if they solve the power/weight problem and can even get good coin/ring sized resolution, how is that any better than VLF? You won't be able to tell coins apart, let alone bottle caps or other round junk. At least on VLF you can tell certain coins and certain round junk (like say a bottle cap or a steel washer) from what your after. Also, for rings, the resolution I doubt will ever be good enough to tell old round tabs from a ring, so once again no real gain there over VLF. Lastly, same problem with junk masking targets. Far as I know ground penetrating radar can't see through metal objects. I'm by no means an expert on ground penetrating imaging but what little I've read on it seems to confirm these things for me. Oh, and one more thing...Even if they can get around the power issues in a hand held unit I doubt the depth will be much more than a few inches that it can image, as I think to go much deeper than that the power requirements shoot right through the roof.