# Relationship history for MSHA mine 3500644

Current hierarchy: **Wildish Land Company → Wildish Medford Sand & Gravel Company → Gilbert 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:** Robert C Gilbert Company Inc → Gilbert Quarry; 1950-01-01 to 1979-11-14; source msha-controller-operator-history
- **controller_controls_mine:** Gilbert Robert C → Gilbert Quarry; 1950-01-01 to 1979-11-14; source msha-controller-operator-history
- **controller_controls_operator:** Gilbert Robert C → Robert C Gilbert Company Inc; 1950-01-01 to 1979-11-14; source msha-controller-operator-history
- **operator_operates_mine:** Wildish Medford Sand & Gravel Company → Gilbert Quarry; 1979-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wildish Land Company → Gilbert Quarry; 1979-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wildish Land Company → Wildish Medford Sand & Gravel Company; 1979-11-15 to current/open; source msha-controller-operator-history