# Relationship history for MSHA mine 1511150

Current hierarchy: **Ashland Inc → Arch On The North Fork Inc → Sassafras**

- 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

- **controller_controls_mine:** Falcon Seaboard Inc → Sassafras; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Sassafras; 1978-04-01 to 1979-02-20; source msha-controller-operator-history
- **controller_controls_operator:** Falcon Seaboard Inc → Falcon Coal Company Inc; 1978-04-01 to 1979-02-20; source msha-controller-operator-history
- **controller_controls_mine:** Diamond Shamrock Corp → Sassafras; 1979-01-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Falcon Coal Company Inc → Sassafras; 1979-02-21 to 1987-09-16; source msha-controller-operator-history
- **controller_controls_operator:** Diamond Shamrock Corp → Falcon Coal Company Inc; 1979-02-21 to 1987-09-16; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc et al → Sassafras; 1987-05-18 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Arch On The North Fork Inc → Sassafras; 1987-09-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc et al → Arch On The North Fork Inc; 1987-09-17 to current/open; source msha-controller-operator-history