# Relationship history for MSHA mine 1515577

Current hierarchy: **Smith Harold G → N & S Coal Inc → #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

- **controller_controls_mine:** Smith Harold G → #1; 1983-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** V-Twin Coal → #1; 1986-04-01 to 1986-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Hendrickson Charles → #1; 1986-04-01 to 1986-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Hendrickson Charles → V-Twin Coal; 1986-04-01 to 1986-06-19; source msha-controller-operator-history
- **operator_operates_mine:** N & S Coal Inc → #1; 1986-06-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Harold G → N & S Coal Inc; 1986-06-20 to current/open; source msha-controller-operator-history