Mining

Corner Monument

A post, stone, or other marker a locator sets at a corner of a mining claim to mark its boundary on the ground. Federal law requires the marking; state law sets the monuments.

Detailed Definition

A corner monument is the post, stone, or other marker a locator sets at a corner of a mining claim to mark its boundary on the ground. Federal law requires the marking; state law sets the monuments. For survey monuments set by BLM's cadastral surveyors, see Monument. For offsets where a true corner cannot be marked, see Witness Monument.

Federal requirements

  • The Mining Law: "The location must be distinctly marked on the ground so that its boundaries can be readily traced" (30 U.S.C. 28).
  • BLM's rules: to locate, "Stake and monument the corners of a mining claim or site which meets applicable state monumenting requirements" (43 CFR 3832.11(c)(2)).
  • BLM's brochure "Mining Claims and Sites on Federal Lands": "Due to wildlife fatalities, the BLM does not allow the use of perforated or uncapped pipes as monuments, corner posts, or side line posts."

How many, by state (lode mining claims)

  • New Mexico: "four substantial posts or monuments, one at each corner of the claim" (NMSA 69-3-1(A)).
  • Colorado: "six substantial posts ... one at each corner and one at the center of each side line" (C.R.S. 34-43-107). Wyoming is similar (W.S. 30-1-103(a)(iii)).
  • Arizona: six, "one at each corner of the claim and one at the center of each end line" (A.R.S. 27-204).

Size and marking, by state

  • Idaho: at least "four (4) feet in height and four (4) inches square or in diameter," and "marked with the name of the claim, the position or number of the corner or angle, and the direction of the boundary lines" (Idaho Code 47-602).
  • Montana: a blazed tree, a set stone, a boulder, or a post "at least 4 inches square by 4 feet 6 inches in length, set 1 foot in the ground"; "it must be marked with the name of the claim and the designation of the corner, either by number or cardinal point" (MCA 82-2-101).
  • California: "A wooden post not less than 11/2 inches in diameter projecting at least two feet above the ground," a mound of stone, or "A nonperforated, capped metal post or solid metal rod" (PRC 3915(a)).

Deadlines, by state

California: "Within 60 days after the date of location" for lode corners (PRC 3901). Montana: 30 days after posting the notice (MCA 82-2-101). Nevada: 60 days after posting (NRS 517.030(1)).

When corners are not required

BLM's brochure says "Mining claims and sites described by legal subdivision in some states do not require the erection of corner monuments." Oregon says placer mining claims taken by legal subdivision "need not be staked or monumented" (ORS 517.046).

Why it matters in mining claim research

The corners on the ground are the location; the recorded description is the locator's account of them. Research compares the corners called for in the certificate with what the state required at the time. A corner missing or unmarked under the state's rule is a weakness in the location.