# Relationship history for MSHA mine 3503936

Current hierarchy: **David R Wilks → KILCHIS ROCK  CO LLC → Kilchis Rock 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:** George J  Williamson → Kilchis Rock Quarry; 1999-10-05 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** CJ Excavating → Kilchis Rock Quarry; 2022-07-28 to 2022-08-17; source msha-controller-operator-history
- **controller_controls_operator:** George J  Williamson → CJ Excavating; 2022-07-28 to 2022-08-17; source msha-controller-operator-history
- **operator_operates_mine:** KILCHIS ROCK  CO LLC → Kilchis Rock Quarry; 2022-08-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David R Wilks → Kilchis Rock Quarry; 2022-08-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David R Wilks → KILCHIS ROCK  CO LLC; 2022-08-18 to current/open; source msha-controller-operator-history