# Relationship history for MSHA mine 1518105

Current hierarchy: **Harold K  Simpson → Simpson Mining Company Inc → Mine #7**

- 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 → Mine #7; 1986-09-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Gentec Processing Inc → Mine #7; 1998-10-01 to 2000-04-20; source msha-controller-operator-history
- **controller_controls_mine:** Allen G  Stump et al → Mine #7; 1998-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Allen G  Stump et al → Gentec Processing Inc; 1998-10-01 to 2000-04-20; source msha-controller-operator-history
- **operator_operates_mine:** Simpson Mining Company Inc → Mine #7; 2000-04-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold K  Simpson → Simpson Mining Company Inc; 2000-04-21 to current/open; source msha-controller-operator-history