# Relationship history for MSHA mine 1510815

Current hierarchy: **Costain Group PLC → Pyro Mining Company → Wheatcroft 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Pyro Energy Corp → Wheatcroft Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pyro Mining Company → Wheatcroft Mine; 1977-10-01 to 1981-06-17; source msha-controller-operator-history
- **controller_controls_operator:** Pyro Energy Corp → Pyro Mining Company; 1977-10-01 to 1981-06-17; source msha-controller-operator-history
- **controller_controls_mine:** Costain Group PLC → Wheatcroft Mine; 1981-04-07 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pyro Mining Company → Wheatcroft Mine; 1981-06-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Costain Group PLC → Pyro Mining Company; 1981-06-18 to current/open; source msha-controller-operator-history