# Relationship history for MSHA mine 2401831

Current hierarchy: **Hand Bill → Bill Hand → Ground Hog Mine & Mill**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Agau-Montoro Joint Venture → Ground Hog Mine & Mill; 1986-09-01 to 1989-06-27; source msha-controller-operator-history
- **controller_controls_mine:** Agau Inc & Montoro Mining Ltd → Ground Hog Mine & Mill; 1986-09-01 to 1989-06-27; source msha-controller-operator-history
- **controller_controls_operator:** Agau Inc & Montoro Mining Ltd → Agau-Montoro Joint Venture; 1986-09-01 to 1989-06-27; source msha-controller-operator-history
- **operator_operates_mine:** Bill Hand → Ground Hog Mine & Mill; 1989-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hand Bill → Ground Hog Mine & Mill; 1989-06-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hand Bill → Bill Hand; 1989-06-28 to current/open; source msha-controller-operator-history