# Relationship history for MSHA mine 1508628

Current hierarchy: **May Wade H → Blue Hawk Coal Corp → No 1 Surface 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

- **operator_operates_mine:** Blue Hawk Coal Corp → No 1 Surface Mine; 1975-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** May Wade H → No 1 Surface Mine; 1975-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** May Wade H → Blue Hawk Coal Corp; 1975-08-01 to current/open; source msha-controller-operator-history