# Relationship history for MSHA mine 1601143

Current hierarchy: **Mckinnon Gordon → Seamco Laboratories Inc → Seamco Pebble**

- 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:** Seamco Laboratories Inc → Seamco Pebble; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mckinnon Gordon → Seamco Pebble; 1987-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mckinnon Gordon → Seamco Laboratories Inc; 1987-10-01 to current/open; source msha-controller-operator-history