# Relationship history for MSHA mine 1502546

Current hierarchy: **Garland Marvin → Garland Coal Co → No 2**

- 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:** Gray & Helton Coal Co → No 2; 1950-01-01 to 1975-05-15; source msha-controller-operator-history
- **controller_controls_mine:** Gray Ancil & Joyce Helton → No 2; 1950-01-01 to 1975-05-15; source msha-controller-operator-history
- **controller_controls_operator:** Gray Ancil & Joyce Helton → Gray & Helton Coal Co; 1950-01-01 to 1975-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Garland Coal Co → No 2; 1975-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Garland Marvin → No 2; 1975-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Garland Marvin → Garland Coal Co; 1975-05-16 to current/open; source msha-controller-operator-history