# Relationship history for MSHA mine 3606661

Current hierarchy: **Laver John H Iii → Maybro Asphalt Company → Maybro Materials Edinboro Pit 2**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** R P  Schreckengost → Maybro Materials Edinboro Pit 2; 1950-01-01 to 1994-09-26; source msha-controller-operator-history
- **operator_operates_mine:** Maybro Asphalt Company → Maybro Materials Edinboro Pit 2; 1978-03-09 to 1994-09-26; source msha-controller-operator-history
- **controller_controls_operator:** R P  Schreckengost → Maybro Asphalt Company; 1978-03-09 to 1994-09-26; source msha-controller-operator-history
- **operator_operates_mine:** Maybro Asphalt Company → Maybro Materials Edinboro Pit 2; 1994-09-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Laver John H Iii → Maybro Materials Edinboro Pit 2; 1994-09-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Laver John H Iii → Maybro Asphalt Company; 1994-09-27 to current/open; source msha-controller-operator-history