I think it dates back to the early 60's. it was used until recently, still a fence around it, I got access through my job. We did find one good piece of jewelry and hunted about 1/50th of the area. Tons of clad from 60-70's in a few hours. No silver coins yet, but I don't know how someone could have picked out all the silver and bypassed all the clad. Alot of the silver rings up in same zone as clad.
Ah, early 1960s origination date, eh? Then forget what I said about yester-year hunters anyhow. Because odds are, you're right: The silver that would possibly be there from the meager few years of circulation (1961, 62, 63, etc...), you're right: probably not much depth difference (albeit another added inch only), when compared to the 1965, 66, etc... pennies and dimes. Not likely this was hit hard for its silver (even if assuming your area had hobbyists 10, 20, and 30 years ago). Reason is, back when pickens were easy, and sites were abundant (the "silver rush" years of the late 1970s to 1980s), most of us poo-pooed something as "new" as the "early 1960s". So, sure, you might find early '60s loss silver (a roosie, a washington, a war nickel, woohoo). But hardly the place I'd fiddle with if silver were my goal (d/t I don't like to wade through that much clad).
But Jason's got a good point: since it's distinctly for swimming, you can bet the jewelry ratio is going to be higher there. If people lounged out the grass sun-bathing, near/by the pool, then your jewelry ratios would go up. Because of the human nature factor of people taking off their jewelry for "safe-keeping", before they swim. They do silly things like hide it in their shoe, or under their beach blanket, etc.. And then ... you guess it, it gets flipped over, lost, etc... Also their lathering up with slippery suntan lotion, coming out of cool waters which just shrank their fingers, etc... All recipes for upping jewelry losses.
So, if the foil and tabs ratio isn't that bad, you might consider chasing those low conductor. But if I'm wrong, and the tabs and foil ratio is punishingly bad, then .... I'd probably stick to sandy beaches for my jewelry, rather than trying to dig 1000 holes in turf for each gold ring.
So you've got a mixed bag there, that only you can decide, based on your ratios, patience, etc... Perhaps holes isn't an issue, since, as you say, the place is abandoned (so not an issue to ruffle up massive amounts of soil, etc..., eh?)
