# Relationship history for MSHA mine 1518186

Current hierarchy: **Progress Energy Inc → Kentucky May Mining → Skull Fork**

- 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:** Yvonne  Yonts et al → Skull Fork; 1997-01-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Don  Robertson → Skull Fork; 1998-01-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky May Mining → Skull Fork; 1999-08-01 to 1999-08-11; source msha-controller-operator-history
- **operator_operates_mine:** 3-D Mining Inc → Skull Fork; 1999-08-12 to 1999-11-02; source msha-controller-operator-history
- **controller_controls_operator:** Don  Robertson → 3-D Mining Inc; 1999-08-12 to 1999-11-02; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky May Mining → Skull Fork; 1999-11-03 to 2000-09-19; source msha-controller-operator-history
- **operator_operates_mine:** Straight Fork Mining Inc → Skull Fork; 2000-09-20 to 2001-08-19; source msha-controller-operator-history
- **controller_controls_operator:** Yvonne  Yonts et al → Straight Fork Mining Inc; 2000-09-20 to 2001-08-19; source msha-controller-operator-history
- **controller_controls_mine:** Florida Progress Corporation → Skull Fork; 2000-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Florida Progress Corporation → Kentucky May Mining; 2000-11-30 to 1999-08-11; source msha-controller-operator-history
- **controller_controls_operator:** Florida Progress Corporation → Kentucky May Mining; 2000-11-30 to 2000-09-19; source msha-controller-operator-history
- **controller_controls_mine:** Progress Energy Inc → Skull Fork; 2000-11-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky May Mining → Skull Fork; 2001-08-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Progress Energy Inc → Kentucky May Mining; 2001-08-20 to current/open; source msha-controller-operator-history