# Relationship history for MSHA mine 2100178

Current hierarchy: **Midwest Asphalt Corp → River Warren Aggregates Inc → Malkerson 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

- **operator_operates_mine:** River Warren Aggregates Inc → Malkerson Quarry; 1950-01-01 to 1980-05-29; source msha-controller-operator-history
- **controller_controls_mine:** Varner Roy S → Malkerson Quarry; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Varner Roy S → River Warren Aggregates Inc; 1950-01-01 to 1980-05-29; source msha-controller-operator-history
- **operator_operates_mine:** River Warren Aggregates Inc → Malkerson Quarry; 1980-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Midwest Asphalt Corp → Malkerson Quarry; 1980-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Midwest Asphalt Corp → River Warren Aggregates Inc; 1980-05-30 to current/open; source msha-controller-operator-history