# Relationship history for MSHA mine 1502502

Current hierarchy: **James River Coal Company → Shamrock Coal Company Incorporated → Shamrock #18 Series**

- 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:** Shamrock Coal Company Inc → Shamrock #18 Series; 1950-01-01 to 1980-01-29; source msha-controller-operator-history
- **controller_controls_mine:** B Ray  Thompson → Shamrock #18 Series; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** B Ray  Thompson → Shamrock Coal Company Inc; 1950-01-01 to 1980-01-29; source msha-controller-operator-history
- **controller_controls_mine:** Sunoco, Inc. → Shamrock #18 Series; 1979-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Shamrock Coal Company Inc → Shamrock #18 Series; 1980-01-30 to 1999-02-16; source msha-controller-operator-history
- **controller_controls_operator:** Sunoco, Inc. → Shamrock Coal Company Inc; 1980-01-30 to 1999-02-16; source msha-controller-operator-history
- **controller_controls_mine:** James River Coal Company → Shamrock #18 Series; 1998-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Shamrock Coal Company Incorporated → Shamrock #18 Series; 1999-02-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James River Coal Company → Shamrock Coal Company Incorporated; 1999-02-17 to current/open; source msha-controller-operator-history