# Relationship history for MSHA mine 4201838

Current hierarchy: **Mike  Ellis; Harold  Ruf → Westroc Inc → Green River 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

- **controller_controls_mine:** Lloyd K  Ash → Green River Pit; 1978-04-01 to 1987-04-22; source msha-controller-operator-history
- **operator_operates_mine:** Ashrock Inc → Green River Pit; 1983-08-01 to 1987-03-11; source msha-controller-operator-history
- **controller_controls_operator:** Lloyd K  Ash → Ashrock Inc; 1983-08-01 to 1987-03-11; source msha-controller-operator-history
- **operator_operates_mine:** Westroc Inc → Green River Pit; 1987-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harold  Ruf et al → Green River Pit; 1987-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Ruf et al → Westroc Inc; 1987-03-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mike  Ellis et al → Westroc Inc; 1987-03-12 to current/open; source msha-controller-operator-history