# Relationship history for MSHA mine 1509821

Current hierarchy: **Hardwick William → B & H Coal Company Inc → Little Prairie Strip**

- 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

- **controller_controls_mine:** Goodaker Garry → Little Prairie Strip; 1975-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Double G Mining Inc → Little Prairie Strip; 1976-06-10 to 1977-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Goodaker Garry → Double G Mining Inc; 1976-06-10 to 1977-02-28; source msha-controller-operator-history
- **operator_operates_mine:** B & H Coal Company Inc → Little Prairie Strip; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hardwick William → Little Prairie Strip; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hardwick William → B & H Coal Company Inc; 1977-03-01 to current/open; source msha-controller-operator-history