# Relationship history for MSHA mine 2602018

Current hierarchy: **Hanson PLC → Bonanza Materials Inc → East Pit**

- 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:** Industrial Construction Inc → East Pit; 1987-07-01 to 1988-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Industrial Construction Inc → East Pit; 1987-07-01 to 1988-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Industrial Construction Inc → Industrial Construction Inc; 1987-07-01 to 1988-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Bonanza Materials Inc → East Pit; 1988-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → East Pit; 1988-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Bonanza Materials Inc; 1988-09-01 to current/open; source msha-controller-operator-history