# Relationship history for MSHA mine 2401476

Current hierarchy: **Hallett Construction Company → Hallett Minerals Company → BLACK BUTTE IRON MINE**

- 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

- **controller_controls_mine:** Hallett Construction Company → BLACK BUTTE IRON MINE; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** R & S Iron Company → BLACK BUTTE IRON MINE; 1979-01-01 to 1980-07-31; source msha-controller-operator-history
- **controller_controls_mine:** John M  Ralls → BLACK BUTTE IRON MINE; 1979-01-01 to 1980-07-31; source msha-controller-operator-history
- **controller_controls_operator:** John M  Ralls → R & S Iron Company; 1979-01-01 to 1980-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Minerals Company → BLACK BUTTE IRON MINE; 1980-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hallett Construction Company → Hallett Minerals Company; 1980-08-01 to current/open; source msha-controller-operator-history