# Relationship history for MSHA mine 2901520

Current hierarchy: **Quintana Copper Flat Ltd & Phibro Mineral Enterpri → Copper Flat Partnership → Copper Flat**

- 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:** Copper Flat Partnership → Copper Flat; 1980-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Quintana Copper Flat Ltd & Phibro Mineral Enterpri → Copper Flat; 1980-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Quintana Copper Flat Ltd & Phibro Mineral Enterpri → Copper Flat Partnership; 1980-05-01 to current/open; source msha-controller-operator-history