# Relationship history for MSHA mine 1512271

Current hierarchy: **Grande Edvard-Thurman Hunter → Ghd Coal Company → No 1 Strip & Auger**

- 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:** D & H Mining Company → No 1 Strip & Auger; 1980-03-01 to 1981-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Grande Edvard → No 1 Strip & Auger; 1980-03-01 to 1981-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Grande Edvard → D & H Mining Company; 1980-03-01 to 1981-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Ghd Coal Company → No 1 Strip & Auger; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grande Edvard-Thurman Hunter Et Al → No 1 Strip & Auger; 1981-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grande Edvard-Thurman Hunter Et Al → Ghd Coal Company; 1981-09-01 to current/open; source msha-controller-operator-history