Apex

The apex is the top of a vein, lode, or ledge. In federal mining law it decides which lode claim may follow a vein downward beyond its own side lines. BLM's Glossary of Surveying and Mapping Terms defines apex as "the outcrop of a vein or the highest portion of a fold in a vein."

The statute

The Mining Law gives lode locators "the exclusive right of possession and enjoyment of all the surface included within the lines of their locations, and of all veins, lodes, and ledges throughout their entire depth, the top or apex of which lies inside of such surface lines extended downward vertically, although such veins, lodes, or ledges may so far depart from a perpendicular in their course downward as to extend outside the vertical side lines of such surface locations" (30 U.S.C. 26).

In short, the lode claim that holds the apex holds the vein on its downward course, within limits. That right is the extralateral right.

What BLM's regulations require

Under 43 CFR 3832.21(a)(3), a lode claim has extralateral rights when the vein extends through its end lines and:

• "The top or apex of the vein, lode, or ledge lies on or under the surface within the interior boundaries of the lode claim"; and
• "The long axis, and therefore the side lines, of the lode claim are substantially parallel to the course of the vein, lode, or ledge."

The Mining Law separately requires: "The end lines of each claim shall be parallel to each other" (30 U.S.C. 23).

Finding the apex

BLM advises that to preserve extralateral rights, a locator "should determine, if possible, the general course of the vein in either direction from the point of discovery in order to mark the correct boundaries of the claim," by tracing the vein on the surface, or by drilling a hole, sinking a shaft, or running a tunnel or drift (43 CFR 3832.21(a)(4)).

Limits

• The right to the outside parts of a vein is "confined to such portions thereof as lie between vertical planes drawn downward as above described, through the end lines of their locations" (30 U.S.C. 26).
• Following a vein does not authorize entry "upon the surface of a claim owned or possessed by another" (30 U.S.C. 26).
• BLM's glossary adds that where veins intersect, "all the ore within the intersection belongs to the senior claimant, but a right of way through the intersection is assured."

Why it matters in mining claim research

Apex rights mean the ground a lode claim controls underground can differ from its surface outline. Where lode claims sit side by side along a vein, the orientation of each mining claim's side lines and end lines, and where the vein reaches the surface, bear on which mining claim holds the vein at depth.