# Relationship history for MSHA mine 2301587

Current hierarchy: **Eric S  Strope → Beck Materials Company → California 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

- **operator_operates_mine:** Lime & Rock Quarries Inc → California Quarry; 1950-01-01 to 1983-04-26; source msha-controller-operator-history
- **controller_controls_mine:** Korte Walter → California Quarry; 1950-01-01 to 1983-04-26; source msha-controller-operator-history
- **controller_controls_operator:** Korte Walter → Lime & Rock Quarries Inc; 1950-01-01 to 1983-04-26; source msha-controller-operator-history
- **controller_controls_mine:** Frank  Twehous → California Quarry; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Capital Materials Company Inc → California Quarry; 1983-04-27 to 1984-03-20; source msha-controller-operator-history
- **controller_controls_operator:** Frank  Twehous → Capital Materials Company Inc; 1983-04-27 to 1984-03-20; source msha-controller-operator-history
- **operator_operates_mine:** Beck Materials Company → California Quarry; 1984-03-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Eric S  Strope et al → California Quarry; 1984-03-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eric S  Strope et al → Beck Materials Company; 1984-03-21 to current/open; source msha-controller-operator-history