# Relationship history for MSHA mine 3400915

Current hierarchy: **Dugan Ed → D & H Dirt → D & H Dirt**

- 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:** Frank Livingston Trucking → D & H Dirt; 1950-01-01 to 1990-10-30; source msha-controller-operator-history
- **controller_controls_mine:** Livingston Frank → D & H Dirt; 1950-01-01 to 1990-10-30; source msha-controller-operator-history
- **controller_controls_operator:** Livingston Frank → Frank Livingston Trucking; 1950-01-01 to 1990-10-30; source msha-controller-operator-history
- **operator_operates_mine:** D & H Dirt → D & H Dirt; 1990-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dugan Ed → D & H Dirt; 1990-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dugan Ed → D & H Dirt; 1990-10-31 to current/open; source msha-controller-operator-history