# Relationship history for MSHA mine 2003504

Current hierarchy: **Amber  Hoover; Amy  Watson; James  Sturrus Jr → High Grade Materials Co → Wayland 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** James P  Sturrus → Wayland Pit; 1998-05-01 to 2019-04-30; source msha-controller-operator-history
- **operator_operates_mine:** High Grade Materials Co → Wayland Pit; 2015-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James P  Sturrus → High Grade Materials Co; 2015-01-01 to 2019-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Amber  Hoover et al → Wayland Pit; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amber  Hoover et al → High Grade Materials Co; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Sturrus Jr et al → High Grade Materials Co; 2019-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Amy  Watson et al → High Grade Materials Co; 2019-05-01 to current/open; source msha-controller-operator-history