# Relationship history for MSHA mine 2002978

Current hierarchy: **Mark T  Clark → Bachman & Clark Construction Company Inc → PORTABLE EL JAY CONE CRUSHER**

- 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

- **operator_operates_mine:** Bachman & Clark Construction Company Inc → PORTABLE EL JAY CONE CRUSHER; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mark T  Clark → PORTABLE EL JAY CONE CRUSHER; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark T  Clark → Bachman & Clark Construction Company Inc; 1996-04-01 to current/open; source msha-controller-operator-history