# Relationship history for MSHA mine 1516566

Current hierarchy: **Harold K  Simpson → Simpson Mining Company Inc → No 4**

- 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:** Solite Corp → No 4; 1974-04-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harold K  Simpson → No 4; 1986-09-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Terry Glenn Coal Company Inc → No 4; 1989-02-01 to 1993-08-16; source msha-controller-operator-history
- **controller_controls_operator:** Solite Corp → Terry Glenn Coal Company Inc; 1989-02-01 to 1993-08-16; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Mining Company Inc → No 4; 1993-08-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold K  Simpson → Simpson Mining Company Inc; 1993-08-17 to current/open; source msha-controller-operator-history