# Relationship history for MSHA mine 1507138

Current hierarchy: **Diamond Shamrock Corp → Falcon Coal Company Inc → Tribbey 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:** Falcon Seaboard Inc → Tribbey Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Combs James → Tribbey Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Combs Coal Company → Tribbey Prep Plant; 1974-07-01 to 1976-03-19; source msha-controller-operator-history
- **controller_controls_operator:** Combs James → Combs Coal Company; 1974-07-01 to 1976-03-19; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Tribbey Prep Plant; 1976-03-20 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Falcon Seaboard Inc → Falcon Coal Company Inc; 1976-03-20 to 1979-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Diamond Shamrock Corp → Tribbey Prep Plant; 1979-01-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Tribbey 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