In restoring corners of irregular claims, such as metes and bounds placers, the broken boundary (non-riparian) or the Grant Boundary method should be used. It may also be applied to lode claims if the above methods do not give adequate results. In reestablishing corners of a block of claims, the rules of proportionate measurement may be applied. In Figure 8, missing Corner No. 2 of claims E, F, G and H can be restored by double proportion. Missing Corner No. 1 of claims A and B may also be restored by double proportion; since there is no corner beyond this corner, the record distance from Corner No. 2 would have to be used in this direction. Corner No. 1 might also be established at the record bearing and distance from Corner No. 2, or lines 1–2 of claims A and B could be made parallel and of equal length to line 3–4 of claim A. Since missing Corner No. 3 of claims B and D is on an end line, single proportionate measurement might be considered. See the Manual of Surveying Instructions for proportionate methods, pp. 134–136. =6–2= Township Resurveys with Mineral Surveys: Prior to field work, all unpatented mineral surveys embracing claims that have been declared null and void should be cancelled, leaving only valid existing claims and patents to be segregated. Restoration of missing corners should only be made where they are necessary to control the boundaries between private and public land, including the boundaries between public land and unpatented valid mineral surveys. Segregation surveys of unsurveyed mining claims may be requested to accommodate administrative actions. If possible, the owners of the mining claims should be advised of the resurvey and given an opportunity to express their opinions as to the position of missing corners. =6–3= Mineral Segregation Surveys: Sections 7–39 to 7–44 inclusive, of the Manual of Surveying Instructions adequately covers this subject. Segregation surveys are not undertaken unless there is a need for them arising from administrative action involving the adjoining land. Very often it will be necessary to make the survey within the boundaries as they are marked on the ground due to inaccuracies in the location survey. The early township surveys in California often segregated unsurveyed mining claims showing them on the township plats without supporting field notes. Resurveys of such segregations may be required based on the evidence found in the field. =6–4= Supplemental Plats: When supplemental plats are required segregating mineral surveys, all such surveys must be segregated. Again, it is desirable that mineral surveys embracing invalid claims be cancelled. The need to lot a cancelled mineral survey will also require a supplemental plat.