# Relationship history for MSHA mine 3602738

Current hierarchy: **Gulf Usa Corp → Cambria Coal Company → Cambria Coal Strips & Tipples**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** C E Powell Coal Co → Cambria Coal Strips & Tipples; 1950-01-01 to 1974-08-28; source msha-controller-operator-history
- **controller_controls_mine:** Powell C E Coal Company → Cambria Coal Strips & Tipples; 1950-01-01 to 1974-08-28; source msha-controller-operator-history
- **controller_controls_operator:** Powell C E Coal Company → C E Powell Coal Co; 1950-01-01 to 1974-08-28; source msha-controller-operator-history
- **operator_operates_mine:** Cambria Coal Company → Cambria Coal Strips & Tipples; 1974-08-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gulf Usa Corp → Cambria Coal Strips & Tipples; 1974-08-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gulf Usa Corp → Cambria Coal Company; 1974-08-29 to current/open; source msha-controller-operator-history