# Relationship history for MSHA mine 4601500

Current hierarchy: **SMC Holding Corp → Mountain Laurel Resources Company → Skelton 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:** CSX Corp → Skelton Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Westmoreland Coal Company → Skelton Mine; 1950-01-01 to 1973-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Westmoreland Coal Company → Skelton Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Westmoreland Coal Company → Westmoreland Coal Company; 1950-01-01 to 1973-11-30; source msha-controller-operator-history
- **operator_operates_mine:** New River Company → Skelton Mine; 1973-12-01 to 1987-03-18; source msha-controller-operator-history
- **controller_controls_operator:** CSX Corp → New River Company; 1973-12-01 to 1987-03-18; source msha-controller-operator-history
- **controller_controls_mine:** SMC Holding Corp → Skelton Mine; 1987-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Laurel Resources Company → Skelton Mine; 1987-03-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** SMC Holding Corp → Mountain Laurel Resources Company; 1987-03-19 to current/open; source msha-controller-operator-history