# Relationship history for MSHA mine 4502730

Current hierarchy: **Middleton Richard W → Anderson & Middleton Lumber Company → A & M 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:** Anderson & Middleton Lumber Company → A & M Pit; 1979-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Middleton Richard W → A & M Pit; 1979-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Middleton Richard W → Anderson & Middleton Lumber Company; 1979-10-01 to current/open; source msha-controller-operator-history