# Relationship history for MSHA mine 2900097

Current hierarchy: **Navajo Transitional Energy Company LLC → Bisti Fuels Company LLC → Navajo 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:** Utah International Inc → Navajo Mine; 1950-01-01 to 1984-04-01; source msha-controller-operator-history
- **controller_controls_mine:** General Electric Company → Navajo Mine; 1950-01-01 to 1984-04-01; source msha-controller-operator-history
- **controller_controls_operator:** General Electric Company → Utah International Inc; 1950-01-01 to 1984-04-01; source msha-controller-operator-history
- **operator_operates_mine:** BHP Navajo Coal Company → Navajo Mine; 1984-04-02 to 2013-12-30; source msha-controller-operator-history
- **controller_controls_mine:** BHP Billiton → Navajo Mine; 1984-04-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BHP Billiton → BHP Navajo Coal Company; 1984-04-02 to 2013-12-30; source msha-controller-operator-history
- **operator_operates_mine:** BHP Billiton Mine Management Company → Navajo Mine; 2013-12-31 to 2016-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Navajo Nation → Navajo Mine; 2013-12-31 to 2019-10-24; source msha-controller-operator-history
- **controller_controls_operator:** Navajo Nation → BHP Billiton Mine Management Company; 2013-12-31 to 2016-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Bisti Fuels Company LLC → Navajo Mine; 2017-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** NACCO Industries Inc → Navajo Mine; 2017-01-01 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_operator:** NACCO Industries Inc → Bisti Fuels Company LLC; 2017-01-01 to 2021-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Navajo Transitional Energy Company LLC → Navajo Mine; 2019-10-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Navajo Transitional Energy Company LLC → BHP Billiton Mine Management Company; 2019-10-25 to 2016-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Navajo Transitional Energy Company LLC → Navajo Mine; 2021-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Navajo Transitional Energy Company LLC → Bisti Fuels Company LLC; 2021-10-01 to current/open; source msha-controller-operator-history