# Relationship history for MSHA mine 4606630

Current hierarchy: **Frisco Donald → Frisco Mining Company → Mine No 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:** Hayhurst James W Ii & Harry H Hill → Mine No 1; 1978-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hayhurst & Hill Inc → Mine No 1; 1983-02-01 to 1984-10-08; source msha-controller-operator-history
- **controller_controls_operator:** Hayhurst James W Ii & Harry H Hill → Hayhurst & Hill Inc; 1983-02-01 to 1984-10-08; source msha-controller-operator-history
- **operator_operates_mine:** Frisco Mining Company → Mine No 1; 1984-10-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Frisco Donald Et Al → Mine No 1; 1984-10-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frisco Donald Et Al → Frisco Mining Company; 1984-10-09 to current/open; source msha-controller-operator-history