# Relationship history for MSHA mine 0202404

Current hierarchy: **Hanson PLC → Hanson Natural Resources Company → AZTEC QUARRY**

- 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:** Santa Fe Pacific Corp → AZTEC QUARRY; 1984-09-01 to 1993-06-24; source msha-controller-operator-history
- **operator_operates_mine:** Western Arizona Rock Products Inc → AZTEC QUARRY; 1987-11-01 to 1988-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Ralph J  Conway → AZTEC QUARRY; 1987-11-01 to 1988-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Ralph J  Conway → Western Arizona Rock Products Inc; 1987-11-01 to 1988-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Western Rock Products Inc → AZTEC QUARRY; 1988-09-01 to 1993-06-24; source msha-controller-operator-history
- **controller_controls_operator:** Santa Fe Pacific Corp → Western Rock Products Inc; 1988-09-01 to 1993-06-24; source msha-controller-operator-history
- **operator_operates_mine:** Hanson Natural Resources Company → AZTEC QUARRY; 1993-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → AZTEC QUARRY; 1993-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Hanson Natural Resources Company; 1993-06-25 to current/open; source msha-controller-operator-history