# Relationship history for MSHA mine 3607129

Current hierarchy: **Yost William S → B & K Coal Company → No 1 Slope**

- 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:** Barrett Coal Company → No 1 Slope; 1981-05-01 to 1984-11-19; source msha-controller-operator-history
- **controller_controls_mine:** Barrett Orren S Et Al → No 1 Slope; 1981-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barrett Orren S Et Al → Barrett Coal Company; 1981-05-01 to 1984-11-19; source msha-controller-operator-history
- **operator_operates_mine:** Skyline Coal Company → No 1 Slope; 1984-11-20 to 1991-12-16; source msha-controller-operator-history
- **controller_controls_mine:** Shiko David R → No 1 Slope; 1984-11-20 to 1991-12-16; source msha-controller-operator-history
- **controller_controls_operator:** Shiko David R → Skyline Coal Company; 1984-11-20 to 1991-12-16; source msha-controller-operator-history
- **operator_operates_mine:** Skyline Coal Company → No 1 Slope; 1991-12-17 to 1992-11-05; source msha-controller-operator-history
- **controller_controls_mine:** Yost Mary → No 1 Slope; 1991-12-17 to 1992-11-05; source msha-controller-operator-history
- **controller_controls_operator:** Yost Mary → Skyline Coal Company; 1991-12-17 to 1992-11-05; source msha-controller-operator-history
- **operator_operates_mine:** B & K Coal Company → No 1 Slope; 1992-11-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Yost William S → No 1 Slope; 1992-11-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Yost William S → B & K Coal Company; 1992-11-06 to current/open; source msha-controller-operator-history