# Relationship history for MSHA mine 2400108

Current hierarchy: **Peabody Energy Corporation → Big Sky Coal Company → Big Sky**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Peabody Coal Company → Big Sky; 1950-01-01 to 1977-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Kennecott Copper Corp → Big Sky; 1950-01-01 to 1977-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Kennecott Copper Corp → Peabody Coal Company; 1950-01-01 to 1977-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Big Sky Coal Company → Big Sky; 1977-07-01 to 1998-05-18; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Big Sky; 1977-07-01 to 1998-05-18; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Big Sky Coal Company; 1977-07-01 to 1998-05-18; source msha-controller-operator-history
- **operator_operates_mine:** Big Sky Coal Company → Big Sky; 1998-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Peabody Energy Corporation → Big Sky; 1998-05-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peabody Energy Corporation → Big Sky Coal Company; 1998-05-19 to current/open; source msha-controller-operator-history