# Relationship history for MSHA mine 3603050

Current hierarchy: **Great American Coal Company → Blue Coal Corp → 1w-34 Retreat Mountain West-Strip**

- 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

- **operator_operates_mine:** Kingston Excavating Company → 1w-34 Retreat Mountain West-Strip; 1950-01-01 to 1973-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Corgan William H → 1w-34 Retreat Mountain West-Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Corgan William H → Kingston Excavating Company; 1950-01-01 to 1973-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Blue Coal Corp → 1w-34 Retreat Mountain West-Strip; 1974-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Great American Coal Company → 1w-34 Retreat Mountain West-Strip; 1974-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Great American Coal Company → Blue Coal Corp; 1974-01-01 to current/open; source msha-controller-operator-history