# Relationship history for MSHA mine 4604933

Current hierarchy: **American Mountaineer Mining Inc → Stevan Coal Company → Switzer No 3 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Stepp Gale B → Switzer No 3 Mine; 1974-04-04 to 1977-05-05; source msha-controller-operator-history
- **operator_operates_mine:** Stevan Coal Company → Switzer No 3 Mine; 1975-11-10 to 1976-05-09; source msha-controller-operator-history
- **controller_controls_operator:** Stepp Gale B → Stevan Coal Company; 1975-11-10 to 1976-05-09; source msha-controller-operator-history
- **operator_operates_mine:** Stevan Coal Company → Switzer No 3 Mine; 1976-05-10 to 1977-05-05; source msha-controller-operator-history
- **controller_controls_mine:** Varner John → Switzer No 3 Mine; 1976-05-10 to 1977-05-05; source msha-controller-operator-history
- **controller_controls_operator:** Varner John → Stevan Coal Company; 1976-05-10 to 1977-05-05; source msha-controller-operator-history
- **operator_operates_mine:** Stevan Coal Company → Switzer No 3 Mine; 1977-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** American Mountaineer Mining Inc → Switzer No 3 Mine; 1977-05-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** American Mountaineer Mining Inc → Stevan Coal Company; 1977-05-06 to current/open; source msha-controller-operator-history