# Relationship history for MSHA mine 3608183

Current hierarchy: **David  Smith → Pocono Sand and Stone → South Sterling 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:** Edwards Sand & Stone → South Sterling Quarry; 1990-06-01 to 2022-11-13; source msha-controller-operator-history
- **controller_controls_mine:** George F  Edwards Jr → South Sterling Quarry; 1990-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George F  Edwards Jr → Edwards Sand & Stone; 1990-06-01 to 2022-11-13; source msha-controller-operator-history
- **operator_operates_mine:** Pocono Sand and Stone → South Sterling Quarry; 2022-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David  Smith → South Sterling Quarry; 2022-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Smith → Pocono Sand and Stone; 2022-11-14 to current/open; source msha-controller-operator-history