# Relationship history for MSHA mine 1503208

Current hierarchy: **Robert C  Billips → Peter Fork Mining Company → Big Shoal Tipple**

- 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:** Kentucky Coal Company → Big Shoal Tipple; 1950-01-01 to 1986-04-17; source msha-controller-operator-history
- **controller_controls_mine:** Nuclear Dynamics Resources Inc → Big Shoal Tipple; 1950-01-01 to 1986-04-17; source msha-controller-operator-history
- **controller_controls_operator:** Nuclear Dynamics Resources Inc → Kentucky Coal Company; 1950-01-01 to 1986-04-17; source msha-controller-operator-history
- **controller_controls_mine:** Robert C  Billips → Big Shoal Tipple; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Peter Fork Mining Company → Big Shoal Tipple; 1986-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert C  Billips → Peter Fork Mining Company; 1986-04-18 to current/open; source msha-controller-operator-history