# Relationship history for MSHA mine 2102968

Current hierarchy: **Dawn M Hass → Hass Construction → B & H Material Co.**

- 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:** Hasco Construction Inc → B & H Material Co.; 1987-08-01 to 1989-05-09; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Hass → B & H Material Co.; 1987-08-01 to 1989-05-09; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Hass → Hasco Construction Inc; 1987-08-01 to 1989-05-09; source msha-controller-operator-history
- **operator_operates_mine:** B & H Material → B & H Material Co.; 1989-05-10 to 2019-06-13; source msha-controller-operator-history
- **controller_controls_mine:** Keith  Hass → B & H Material Co.; 1989-05-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keith  Hass → B & H Material; 1989-05-10 to 2019-06-13; source msha-controller-operator-history
- **operator_operates_mine:** Hass Construction → B & H Material Co.; 2019-06-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dawn M Hass → B & H Material Co.; 2020-05-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dawn M Hass → Hass Construction; 2020-05-18 to current/open; source msha-controller-operator-history