# Relationship history for MSHA mine 1516908

Current hierarchy: **Harold K  Simpson → Simpson Mining Company,  Inc → #9**

- 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:** Harold K  Simpson → #9; 1986-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Clayton V  Roberts → #9; 1990-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bearpen Collieries Inc → #9; 1990-06-01 to 2001-04-23; source msha-controller-operator-history
- **controller_controls_operator:** Clayton V  Roberts → Bearpen Collieries Inc; 1990-06-01 to 2001-04-23; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Mining Company,  Inc → #9; 2001-04-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold K  Simpson → Simpson Mining Company,  Inc; 2001-04-24 to current/open; source msha-controller-operator-history