# Relationship history for MSHA mine 0504340

Current hierarchy: **Keever Mitch → American Materials Inc → Burnt River Quarry**

- 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

- **controller_controls_mine:** Keever Mitch → Burnt River Quarry; 1986-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** American Materials Inc → Burnt River Quarry; 1988-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keever Mitch → American Materials Inc; 1988-04-01 to current/open; source msha-controller-operator-history