I've found 15 so far. Revier gives some good info.
Basically the best areas are places where travelers came & went from. Especially long-distance travel (ie.: not just local-stages that ran between small-towns inner-county type travel). Because: Any time there was need to uproot and travel to an altogether new destination (ie.: sell your farm in one state, and move to another state, for long-distance travel), then: You would tend to consolidate your wealth, to move. And in an era before credit cards, inter-state banking, telegram-wiring of $, etc... persons would actually carry their wealth with them. And ... since cargo weight and space was at a premium, then go figure : What's lighter: 100 large cents ? Or a $1 gold piece ? What's lighter : 50 dimes (or 500 LCs), or a single $5 gold piece ?
So I have found several of my gold coins at the east-to-west migration route stop locations. Since a lot of the migration, in those days, starting from the gold rush, all the way to the early 1900s, was of course east-to-west. Trading post /spring stops, stage stops, etc...
2 of mine were found at a location said-to-have been a military camp area @ the 1840s to early 1850s. Which makes sense in what Revier was referring to. Ie.: that there were some years (not all the years) when the govt. paid soldiers in some geographic locations (not all locations) in gold coins.
But then the remaining ones were found at things like : Old town demolition sites (bleacher grandstand teardown, oldtown sidewalk tearout, & old bldg. teardown). Another 4 were after beach storm erosion and 1 in park turf, and 1 at a defunct mineral springs resort. (so I would attribute those to recreation time user's losses).
They also seem to be found a LOT more often in western states, than in eastern states. I could try to attribute this to the east-west-migration-cargo-weight theory. But : About 2/3 of my gold coins are S mints. So that sort of blows that theory. Yet the others (specifically the ones found @ the locations where travelers would have been stopping @ their travel inward from the east) did have the eastern mints.
As far as the machines used : Everything from back in my Whites days, up to my Minelab days. No rhyme or reason. And contrary to popular notion: Gold coins are not low conductors. So you don't need a machine that "excels at low conductors", to have better odds at finding them. The $5, for example, reads at the corroded zinc TID range (about 48 to 49-ish, on the old Whites scale) . And a $10 reads @ around the low IH zone. And a $20 reads almost up by copper penny or so.
The ones that could be arguably "low conductors" are the $2.50, which reads @ the pulltab range. And as we all know : EVEN CHEAPIE MACHINES have no problem finding pulltabs (as long as you lower the disc. knob, haha). The only gold coin that is TRULY a low conductor, is the $1 gold . The TID is about at the beaver-tail of tabs . But still not difficult to get, as long as your disc. knob isn't cranked up. And of all the denominations: The $5 was the most highly circulated denomination. And as you can see, you can even knock out round tabs, and still not miss a $5 gold.
But the TID's , and machines used, is hardly the discussion to be had, when discussing upping one's odds at finding a gold coin. Instead, the MUCH LARGER discussion is: Location location location. Be at cross-country type travel stop locations. Be at military fort site locations that date to the 1840s to late 1850s. Be at west coast locations where you're getting coins in the date range of the mid to late 1800s (preferably stage stops).
Another few tips:
1) Gold coins weren't necessarily circulated in the same fashion as pennies, nickels, dimes, quarters, etc..... Because, for example, $5 or $10 could be like an entire week's pay for a working-stiff. So .... just like today .... not likely you are carrying $500 cash in your wallet. Instead, you deposit your weekly check, and carry $1s and $5s in your wallet. So too was it back then: People would handle gold coins when preparing to make larger purchases. Like down-payment on a house. Or to purchase livestock , etc.... But otherwise, stashed away, in the same fashion that you don't carry large sums of cash. Not carried like daily pocket change.
2) Even though gold coins were minted up to the 1910s and 1920s, yet: Very very rarely are gold coins found that date past 1900. Because things like paper checks were coming into vogue . Ability to wire money was coming into vogue and reaching even smaller towns by then. RR and auto travel were taking the place of stages by then, reaching more and more places that had previously been strictly horse-back and stage. etc... So you'll notice that of all the gold coins that get floated on forum show-&-tells, that : a) Most of them are $5 denomination, and b) they are mostly pre 1900 dates.
