# Relationship history for MSHA mine 1508761

Current hierarchy: **Prichard Larry S → P & O Mining Company Inc → No 1 Surface**

- 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

- **controller_controls_mine:** Prichard Larry S → No 1 Surface; 1975-03-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big Fork Coal Co Inc → No 1 Surface; 1975-08-01 to 1977-05-03; source msha-controller-operator-history
- **controller_controls_mine:** Dansby C E → No 1 Surface; 1975-08-01 to 1977-05-03; source msha-controller-operator-history
- **controller_controls_operator:** Dansby C E → Big Fork Coal Co Inc; 1975-08-01 to 1977-05-03; source msha-controller-operator-history
- **operator_operates_mine:** P & O Mining Company Inc → No 1 Surface; 1977-05-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Prichard Larry S → P & O Mining Company Inc; 1977-05-04 to current/open; source msha-controller-operator-history