# Relationship history for MSHA mine 1201415

Current hierarchy: **Georges Roger V → Four Rivers Coal Company Inc → Sky Point Pit**

- 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:** Koester Mining Corp → Sky Point Pit; 1975-01-01 to 1976-09-20; source msha-controller-operator-history
- **controller_controls_mine:** Vigo Coal Company Incorporated → Sky Point Pit; 1975-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vigo Coal Company Incorporated → Koester Mining Corp; 1975-01-01 to 1976-09-20; source msha-controller-operator-history
- **operator_operates_mine:** Four Rivers Coal Company Inc → Sky Point Pit; 1976-09-21 to 1983-06-30; source msha-controller-operator-history
- **controller_controls_mine:** National Bulk Carriers → Sky Point Pit; 1976-09-21 to 1983-06-30; source msha-controller-operator-history
- **controller_controls_operator:** National Bulk Carriers → Four Rivers Coal Company Inc; 1976-09-21 to 1983-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Four Rivers Coal Company Inc → Sky Point Pit; 1983-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Georges Roger V → Sky Point Pit; 1983-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Georges Roger V → Four Rivers Coal Company Inc; 1983-07-01 to current/open; source msha-controller-operator-history