# Relationship history for MSHA mine 1516591

Current hierarchy: **Zeigler Coal Holding Company → Knott County Mining Company → Crager Fork Strip**

- 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:** Knott County Mining Company → Crager Fork Strip; 1989-03-01 to 1992-11-22; source msha-controller-operator-history
- **controller_controls_mine:** Shell Oil Company → Crager Fork Strip; 1989-03-01 to 1992-11-22; source msha-controller-operator-history
- **controller_controls_operator:** Shell Oil Company → Knott County Mining Company; 1989-03-01 to 1992-11-22; source msha-controller-operator-history
- **operator_operates_mine:** Knott County Mining Company → Crager Fork Strip; 1992-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Zeigler Coal Holding Company → Crager Fork Strip; 1992-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Zeigler Coal Holding Company → Knott County Mining Company; 1992-11-23 to current/open; source msha-controller-operator-history