# Relationship history for MSHA mine 1510312

Current hierarchy: **Crawford Kenneth → Crawford Coal Company → No 2 Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Crawford Kenneth Et Al → No 2 Mine; 1976-07-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Crawford Coal Company → No 2 Mine; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crawford Kenneth Et Al → Crawford Coal Company; 1977-03-01 to current/open; source msha-controller-operator-history