A number of oil shale placer claims were in existence at the time the Mineral Leasing Act was passed in 1920, and have subsequently been patented. Many discontinued performing the annual assessment work on the theory that no one else could locate the claim. The Department of the Interior has recently ruled (U.S. v. Frank W. Winnegar et al.; 81 I.D. 370) that failure to develop an oil shale claim demonstrates that the deposit is not valuable and that the rule of the prudent man has not been met. =2–5= Discovery Work: As with lodes, the State requirements for discovery work have been eliminated for all but the State of Washington. However, sufficient excavation will be necessary to disclose a valuable deposit. =2–6= Location: The Act of 1870 limited placer claims to 160 acres, whether they be located by an individual or association; the Act of 1872 limited locations to 20 acres per person, with up to 160 acres for an association of eight persons. Therefore, two persons may take 40 acres; three take 60 acres; four take 80 acres, etc. If practicable, placer claims shall conform to the legal subdivisions of the public land survey, with ten acres being the smallest unit considered. If on unsurveyed lands, a placer claim should conform to the protracted survey. If on surveyed lands, no further description is necessary and the claim may proceed to patent on this basis. State law may require monumentation of the corners. If on unsurveyed lands a mineral survey will be required before application for patent can be made. Further limitation on size of precious metal placers is imposed by the State of Alaska. There is no limit on the number of placer claims that may be located. Where fractional lots of the public land survey are encountered, the rule of approximation may be applied to excess acreage. The rule is that the amount of excess may not exceed the amount of loss, if one of the subdivisions were eliminated. On the basis of ten acre tracts, the allowable excess would be 4.99 acres. There are instances where conformity to the public land survey is not practical. These instances occur where conformity would take in a sizable amount of non-mineral ground, such as a gulch placer, where the claim is surrounded by prior locations or conformity would necessitate placing the lines on prior claims. In these cases, a metes and bounds description is proper, but with the following limitation: A location by one or two persons must be included within a square 40 acre tract; a location by three or four persons within two square 40 acre tracts placed end to end; a location by five or six persons within three square 40 acre tracts; seven or eight persons within four square 40 acre tracts. (43 C.F.R. 3842.1–5) Regardless of the manner in which a placer is described, a location notice and/or certificate must be posted and filed for record. A sample certificate is included in the appendix. Mill Sites