# Relationship history for MSHA mine 1401762

Current hierarchy: **Robert  Davies; Doug  Shilling; Mike  Shilling → Hartford Sand & Gravel → Hartford 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Hartford Sand & Gravel → Hartford Pit; 2013-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Davies et al → Hartford Pit; 2013-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Davies et al → Hartford Sand & Gravel; 2013-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Doug  Shilling et al → Hartford Sand & Gravel; 2013-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mike  Shilling et al → Hartford Sand & Gravel; 2013-05-29 to current/open; source msha-controller-operator-history