# Relationship history for MSHA mine 1201936

Current hierarchy: **Farrell Byron → Contract Mining Inc → Blanca #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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Farrell Byron → Blanca #1; 1981-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Contract Mining Inc → Blanca #1; 1984-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Farrell Byron → Contract Mining Inc; 1984-05-01 to current/open; source msha-controller-operator-history