# Relationship history for MSHA mine 0901273

Current hierarchy: **Doris Ann  Gunter; Mark  Hill → QUARRIES, INC → Sandy Cross Blue Quarry**

- 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

- **controller_controls_mine:** Calvin  Hill et al → Sandy Cross Blue Quarry; 1950-01-01 to 2018-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Doris Ann  Gunter et al → Sandy Cross Blue Quarry; 2018-04-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** QUARRIES, INC → Sandy Cross Blue Quarry; 2026-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doris Ann  Gunter et al → QUARRIES, INC; 2026-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Hill et al → QUARRIES, INC; 2026-08-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Calvin  Hill et al → QUARRIES, INC; 2026-08-26 to 2018-04-29; source msha-controller-operator-history