The claimant should also make a search of the Bureau of Land Management records, particularly the Master Title Plats (M.T. Plats) to determine conflict with prior patents and withdrawals. Connecting sheets, if available, which show in outline all approved mineral surveys, should also be examined for conflicts with prior mineral surveys. The BLM record of unsurveyed locations should also be searched. The claimant should make certain that his discovery point is on vacant public domain, which includes minerals reserved to the United States where the patent is for the surface only. If two or more claims are involved, each must have its own discovery and both discoveries may not be in an area of conflict between two claims. The length and width of each lode claim must be checked to make certain that statutory length of 1500 feet has not been exceeded and that the right angle distance of no more than 300 feet exists on each side of the presumed course of the vein (lode line). The acreage of all claims and the length of placers must be checked for excess. If excesses appear to exist the mineral surveyor should be advised of them and directed to survey the claim within the boundaries given so as to eliminate such excess. While metes and bounds descriptions of lode claims are not mandatory, the description must be such that the locus of the claim can be determined. While a tie to a section is preferable, a tie to another mineral survey, mineral location monument, or triangulation station of the National Geodetic Survey or U.S. Geological Survey is acceptable provided they can be identified with the public land survey. Ties to bench marks are not acceptable. Irregular claims, such as placer claims or mill sites, must have a metes and bounds description closing within 0.50 feet in 1,000 feet. The acreage of lode claims cannot exceed 20.661 acres. Placers may not exceed 20 acres to each claimant, exclusive of conflict, and mill sites may not exceed 5 acres, exclusive of conflict. One of the location certificate copies must be certified by the custodian of the local records, usually the County Clerk and Recorder. If any of the above items are not in order, it will be necessary to require the claimant to file an amended location certificate that will properly describe the claim. If the error in the certificate is small, or there is an obvious clerical error, such as calling for a bearing of N.——W. when it should be N.——E. it will suffice to state in the final field notes that the location certificate is in error. To aid in determining the locus and relative position of several claims, the claimant may be called upon to furnish a diagram. If the certificate is marginal in detail, it is proper to suggest to the mineral surveyor that an amended location certificate be filed and an amended order for survey obtained before completing his survey. It is also proper to set a time limit for the completion of the survey and filing returns.