# Relationship history for MSHA mine 0404303

Current hierarchy: **Nixon J E → Sierra Mines Company → Sierra 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Hannix Mines Company → Sierra Mine; 1979-01-01 to 1980-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Nixon J E → Sierra Mine; 1979-01-01 to 1980-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Nixon J E → Hannix Mines Company; 1979-01-01 to 1980-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Tom Lindbloom & Associates → Sierra Mine; 1981-01-01 to 1981-09-01; source msha-controller-operator-history
- **controller_controls_mine:** Lindbloom Tom → Sierra Mine; 1981-01-01 to 1981-09-01; source msha-controller-operator-history
- **controller_controls_operator:** Lindbloom Tom → Tom Lindbloom & Associates; 1981-01-01 to 1981-09-01; source msha-controller-operator-history
- **operator_operates_mine:** Winney Construction Company → Sierra Mine; 1981-09-02 to 1983-01-27; source msha-controller-operator-history
- **controller_controls_mine:** Winney Curtis → Sierra Mine; 1981-09-02 to 1983-01-27; source msha-controller-operator-history
- **controller_controls_operator:** Winney Curtis → Winney Construction Company; 1981-09-02 to 1983-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Sierra Mines Company → Sierra Mine; 1983-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nixon J E → Sierra Mine; 1983-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nixon J E → Sierra Mines Company; 1983-01-28 to current/open; source msha-controller-operator-history