# Relationship history for MSHA mine 1101215

Current hierarchy: **William Charles Ltd → Rockford Sand & Gravel Inc → South Main Sand & Gravel Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Rockford Sand & Gravel Inc → South Main Sand & Gravel Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William Charles Ltd → South Main Sand & Gravel Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William Charles Ltd → Rockford Sand & Gravel Inc; 1950-01-01 to current/open; source msha-controller-operator-history