# Relationship history for MSHA mine 4502687

Current hierarchy: **Asea Brown Boveri Ltd (ABB) → C-E Minerals Inc → C E Minerals Flagstaff Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Tri-H Mining Company Inc → C E Minerals Flagstaff Mine; 1979-01-01 to 1980-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Hurn Ronald → C E Minerals Flagstaff Mine; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hurn Ronald → Tri-H Mining Company Inc; 1979-01-01 to 1980-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Asea Brown Boveri Ltd (ABB) → C E Minerals Flagstaff Mine; 1980-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sell Flagstaff Barite Company → C E Minerals Flagstaff Mine; 1980-11-01 to 1981-12-03; source msha-controller-operator-history
- **controller_controls_mine:** Sell Leonard L-Sidney L & Wesley C → C E Minerals Flagstaff Mine; 1980-11-01 to 1981-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Sell Leonard L-Sidney L & Wesley C → Sell Flagstaff Barite Company; 1980-11-01 to 1981-12-03; source msha-controller-operator-history
- **operator_operates_mine:** C-E Minerals Inc → C E Minerals Flagstaff Mine; 1981-12-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Asea Brown Boveri Ltd (ABB) → C-E Minerals Inc; 1981-12-04 to current/open; source msha-controller-operator-history