# Relationship history for MSHA mine 1513403

Current hierarchy: **Larry  Cambell → Sand Hill Energy Inc → Sand Hill**

- 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:** Sand Hill Energy Inc → Sand Hill; 1982-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Randall  Wagers et al → Sand Hill; 1982-03-01 to 2003-01-19; source msha-controller-operator-history
- **controller_controls_operator:** Randall  Wagers et al → Sand Hill Energy Inc; 1982-03-01 to 2003-01-19; source msha-controller-operator-history
- **controller_controls_mine:** Larry  Cambell et al → Sand Hill; 2003-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry  Cambell et al → Sand Hill Energy Inc; 2003-01-20 to current/open; source msha-controller-operator-history