# Relationship history for MSHA mine 2100904

Current hierarchy: **Halliburton Company → Federal Ore & Chemicals Inc → Burnett Mill**

- 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

- **controller_controls_mine:** Panhandle Eastern Corp → Burnett Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hallett Minerals Company → Burnett Mill; 1950-01-01 to 1978-01-23; source msha-controller-operator-history
- **controller_controls_mine:** Hallett Construction Company → Burnett Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hallett Construction Company → Hallett Minerals Company; 1950-01-01 to 1978-01-23; source msha-controller-operator-history
- **operator_operates_mine:** Federal Bentonite Div/Aurora Metal Company → Burnett Mill; 1978-01-24 to 1984-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Panhandle Eastern Corp → Federal Bentonite Div/Aurora Metal Company; 1978-01-24 to 1984-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Halliburton Company → Burnett Mill; 1984-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Federal Ore & Chemicals Inc → Burnett Mill; 1984-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Halliburton Company → Federal Ore & Chemicals Inc; 1984-10-01 to current/open; source msha-controller-operator-history