# Relationship history for MSHA mine 4702526

Current hierarchy: **Harless Bill → Vernon Stone → Plant No 1**

- 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:** Darrell Rossing Trucking & Excavating → Plant No 1; 1950-01-01 to 1986-09-22; source msha-controller-operator-history
- **controller_controls_mine:** Darrell  Rossing → Plant No 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darrell  Rossing → Darrell Rossing Trucking & Excavating; 1950-01-01 to 1986-09-22; source msha-controller-operator-history
- **operator_operates_mine:** Vernon Stone → Plant No 1; 1986-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harless Bill → Plant No 1; 1986-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harless Bill → Vernon Stone; 1986-09-23 to current/open; source msha-controller-operator-history