# Relationship history for MSHA mine 1506918

Current hierarchy: **Diamond Shamrock Corp → Falcon Coal Company Inc → Fourseam Prep Plant**

- 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:** Elmer  Whitaker → Fourseam Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Falcon Seaboard Inc → Fourseam Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Whitaker Coal Corp → Fourseam Prep Plant; 1974-01-25 to 1974-07-08; source msha-controller-operator-history
- **controller_controls_operator:** Elmer  Whitaker → Whitaker Coal Corp; 1974-01-25 to 1974-07-08; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Fourseam Prep Plant; 1974-07-09 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Falcon Seaboard Inc → Falcon Coal Company Inc; 1974-07-09 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Diamond Shamrock Corp → Fourseam Prep Plant; 1979-01-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Fourseam Prep Plant; 1979-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Diamond Shamrock Corp → Falcon Coal Company Inc; 1979-02-01 to current/open; source msha-controller-operator-history