# Relationship history for MSHA mine 1511741

Current hierarchy: **Dan  Chambers → Wash Ridge Coal Company Inc → Prep Plant #1**

- 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:** D H Campbell → Prep Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dan  Chambers et al → Prep Plant #1; 1977-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Tayloe Paul D → Prep Plant #1; 1978-03-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** D H Campbell Inc → Prep Plant #1; 1978-12-01 to 1983-05-25; source msha-controller-operator-history
- **controller_controls_operator:** D H Campbell → D H Campbell Inc; 1978-12-01 to 1983-05-25; source msha-controller-operator-history
- **operator_operates_mine:** K Y V A Coals Inc → Prep Plant #1; 1983-05-26 to 1985-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Tayloe Paul D → K Y V A Coals Inc; 1983-05-26 to 1985-02-28; source msha-controller-operator-history
- **operator_operates_mine:** D H Campbell Inc → Prep Plant #1; 1985-03-01 to 1992-11-15; source msha-controller-operator-history
- **controller_controls_operator:** D H Campbell → D H Campbell Inc; 1985-03-01 to 1992-11-15; source msha-controller-operator-history
- **operator_operates_mine:** Wash Ridge Coal Company Inc → Prep Plant #1; 1992-11-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dan  Chambers et al → Wash Ridge Coal Company Inc; 1992-11-16 to current/open; source msha-controller-operator-history