So it sounds like possiblethe lode filling is not the correct filling for the area? The hydro scar is about 5 times the size of 20.66 and the "lode" is placer gold scattered through the entire scar. At one time there was a volcanic cap covering the workings but this has been gone since 1890.. There is a drift mine under the scar I've head, is it possible the claim is for the drift and he just assumes the surface minerals as well?
Most of the ancient subsurface placer deposits were properly located as lodes. Drift mines and much hydraulic work was carried out underground in consolidated material. Placer claims are for unconsolidated surface deposits. The fact that the original gold deposit was alluvial doesn't matter if the deposit was covered and consolidated over eons.
The proper way to locate a claim over tailings is by placer. Not knowing the deposit type or what the mining intent of the locator was I can't really determine which type of claim was proper. It doesn't really matter because whether the claim is placer or lode the claimant still owns
all the valuable minerals within the location. Lode claimants own the associated placer material and placer claimants own any lodes found within their location.
You could try to argue that the claim type is not supported by the deposit type but to do that you would have to have first hand knowledge of the existing deposit. You can only do that with the permission of the claim owner.
If you were able to get permission to prospect the claim and you discovered there was no lode (ever try to prove a negative?) you would have to sue the claim owner to have their claim voided. Suing to void a claim to your advantage based on paper errors (type of claim) is known as claim jumping. Claim jumping is frowned on by the courts, your odds of winning such a case are really small. Not only that it would be really bad manners to sue the claim owner who gave you permission to prospect their claim, in my opinion.
Goldwasher is right. Lode claims are located by metes and bounds (distance and direction). There is no exemption for staking as there is for placer locations in some states. Lode claims can not be located by aliquot part.
The centerline of a lode claim follows the assumed direction of the strike. Lode claims are a maximum of 600 feet (300 foot on either side of the centerline) by 1500 feet (along the strike) that adds up to 20.66 acres. Lode claims can be smaller but the maximum dimensions still apply and the minimum dimension of the end line is 25 foot per side (50 foot width total). Lode claims require a minimum of 5 stakes - 4 corners and the discovery point monument. Some states require two end line center stakes as well so in those states lode claims will have a minimum of 7 stakes.
The vast majority of mining claims in the U.S. are lode claims (about 85%). They are located differently from placer claims but that in itself should not be suspicious. Try getting a copy of the location notice(s) for the lodes there and see just where they are located. You might have an opportunity to work around the existing claims and get some gold.
Heavy Pans