# Relationship history for MSHA mine 0500416

Current hierarchy: **Atlantic Richfield Company → Anaconda Minerals Company → Rico Complex**

- 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:** Atlantic Richfield Company → Rico Complex; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rico-Argentine Mining Company → Rico Complex; 1950-01-01 to 1980-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Crystal Oil Company → Rico Complex; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crystal Oil Company → Rico-Argentine Mining Company; 1950-01-01 to 1980-09-14; source msha-controller-operator-history
- **operator_operates_mine:** Anaconda Minerals Company → Rico Complex; 1980-09-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Atlantic Richfield Company → Anaconda Minerals Company; 1980-09-15 to current/open; source msha-controller-operator-history