# Relationship history for MSHA mine 3606688

Current hierarchy: **Harold P  Leasure → Van Leer Coal Company → Vanleer #1 Strip**

- 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:** Van Leer Coal Company → Vanleer #1 Strip; 1978-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Harold P  Leasure et al → Vanleer #1 Strip; 1978-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold P  Leasure et al → Van Leer Coal Company; 1978-06-01 to current/open; source msha-controller-operator-history