## Facts

- Del Monte Mining & Milling Co. held a patented lode claim (Del Monte) in Colorado; Last Chance Mining & Milling Co. held a later-issued patent for its lode claim (Last Chance).
- A third patented claim (New York) lay between the two and affected the surface geometry and the course of the disputed vein.
- The vein’s apex and the surface boundaries produced overlaps and irregular tracts after prior adverse-claim litigation and patent exclusions.
- The Last Chance patent described a larger figure but excluded ground previously patented to the New York claim, leaving separated or irregular remaining tracts.
- The controversy concerned whether Last Chance could define and exercise extralateral rights to follow the vein on its dip beyond its vertical side lines, potentially beneath Del Monte’s surface.
- The case reached the Supreme Court on questions of law certified by the federal court of appeals, rather than on a full merits judgment.

## Issues

1. Whether a junior lode locator may lay claim lines within, upon, or across the surface of a valid senior location to define extralateral rights, so long as senior rights are not infringed.
2. Whether a patent that describes a larger tract but excepts prior patented ground conveys more than a patent describing only the remaining irregular tracts.
3. Whether the easterly side line of the New York claim could be treated as an “end line” of the Last Chance claim for purposes of Revised Statutes §§ 2320 and 2322.
4. Whether, when a vein’s apex crosses one end line and one side line of a claim, the locator may follow the vein on its dip beyond the vertical side line.
5. Whether, on these facts, Last Chance could follow the vein beyond its west side line beneath Del Monte.

## Decision

- The Court answered Issue 1 yes, with the limitation that no forcible entry or disturbance of possession occurs and no senior rights are impaired.
- The Court gave no separate answer to Issue 2, treating it as sufficiently addressed within its discussion of Issue 1 and the statutory limits on mining rights.
- The Court answered Issue 3 no: another claim’s side line could not be treated as an end line of Last Chance.
- The Court answered Issue 4 yes: crossing one end line and one side line does not, by itself, defeat the ability to follow the vein beyond the vertical side line if statutory conditions are met.
- The Court declined to answer Issue 5 because it effectively sought a fact-bound resolution of the entire controversy, beyond the proper scope of certified questions.

## Legal Principles

- Extralateral rights to pursue a vein beyond vertical side lines are statutory; a claimant must satisfy the statutory conditions governing apex and end lines.
- Federal mining law does not authorize trespass or physical invasion of land held in private ownership; rights defined by location cannot justify forcible entry on senior patented ground.
- A junior locator may draw location lines that overlap a senior claim’s surface to define permissible underground rights, but only insofar as those asserted rights do not conflict with the senior claimant’s established rights and no possession is disturbed.
- “End lines” for extralateral purposes are determined by the claimant’s own location as bounded under the mining statutes; a boundary of a separate claim cannot be recharacterized as the claimant’s end line to expand extralateral reach.
- When the apex crosses one end line and one side line, the locator may still follow the vein on its dip beyond the vertical side line, provided the statutory framework for extralateral rights is otherwise satisfied.
- On certified questions, the Supreme Court answers abstract questions of law and will not decide the entire case by resolving disputed, fact-specific applications.

## Conclusion

The Court clarified that mining extralateral rights exist only within the federal statutory scheme: junior claims may be laid across senior surface boundaries only without forcible entry and without impairing senior rights; neighboring boundaries cannot be treated as a claimant’s end lines; and a vein apex crossing an end line and a side line may still support following the vein beyond a side line, while fact-intensive application remained for the lower court.


Del Monte Mining & Milling Co. v. Last Chance Mining & Milling Co., 171 U.S. 55 (1898)