# Relationship history for MSHA mine 1515774

Current hierarchy: **Paul  Welch → Welch Sand & Gravel Company → Welch Sand & Gravel Co**

- 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:** Welch Sand & Gravel Company → Welch Sand & Gravel Co; 1986-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paul  Welch → Welch Sand & Gravel Co; 1986-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul  Welch → Welch Sand & Gravel Company; 1986-10-01 to current/open; source msha-controller-operator-history