# Relationship history for MSHA mine 2600091

Current hierarchy: **Crowell J Irving Jr → J Irving Crowell & Son → Crowell Fluorspar Mine**

- 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:** J Irving Crowell & Son → Crowell Fluorspar Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Crowell J Irving Jr → Crowell Fluorspar Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Crowell J Irving Jr → J Irving Crowell & Son; 1950-01-01 to current/open; source msha-controller-operator-history