# Relationship history for MSHA mine 4002161

Current hierarchy: **Penta Corp → Marion & Bush Mining Company → Penta No 4 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

- **operator_operates_mine:** Nabors Coal Company Inc → Penta No 4 Surface; 1976-12-01 to 1977-03-13; source msha-controller-operator-history
- **controller_controls_mine:** Morrow Hugh → Penta No 4 Surface; 1976-12-01 to 1977-03-13; source msha-controller-operator-history
- **controller_controls_operator:** Morrow Hugh → Nabors Coal Company Inc; 1976-12-01 to 1977-03-13; source msha-controller-operator-history
- **operator_operates_mine:** Marion & Bush Mining Company → Penta No 4 Surface; 1977-03-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Penta Corp → Penta No 4 Surface; 1977-03-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Penta Corp → Marion & Bush Mining Company; 1977-03-14 to current/open; source msha-controller-operator-history