# Relationship history for MSHA mine 1509501

Current hierarchy: **Augspurger Austin & C B Byrge → Hawk Coal Company → No 1 Prep Plant**

- 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:** R B S Inc → No 1 Prep Plant; 1976-02-01 to 1979-10-30; source msha-controller-operator-history
- **controller_controls_mine:** Schweitzer Roy B → No 1 Prep Plant; 1976-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Schweitzer Roy B → R B S Inc; 1976-02-01 to 1979-10-30; source msha-controller-operator-history
- **operator_operates_mine:** Big K Energy & Coal Sales Inc → No 1 Prep Plant; 1979-10-31 to 1983-09-08; source msha-controller-operator-history
- **controller_controls_mine:** Sizemore Wayne & Steve → No 1 Prep Plant; 1979-10-31 to 1983-09-08; source msha-controller-operator-history
- **controller_controls_operator:** Sizemore Wayne & Steve → Big K Energy & Coal Sales Inc; 1979-10-31 to 1983-09-08; source msha-controller-operator-history
- **operator_operates_mine:** Hawk Coal Company → No 1 Prep Plant; 1983-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Augspurger Austin & C B Byrge → No 1 Prep Plant; 1983-09-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Augspurger Austin & C B Byrge → Hawk Coal Company; 1983-09-09 to current/open; source msha-controller-operator-history