# Relationship history for MSHA mine 3901206

Current hierarchy: **Arlan  Carlson; Douglas  Carlson → Carlson Pit and Mill → Carlson Pit and 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:** Carlson Pit and Mill → Carlson Pit and Mill; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Douglas  Carlson  et al → Carlson Pit and Mill; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas  Carlson  et al → Carlson Pit and Mill; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Arlan  Carlson  et al → Carlson Pit and Mill; 1979-01-01 to current/open; source msha-controller-operator-history