# Relationship history for MSHA mine 0404818

Current hierarchy: **Steelhead Resources Ltd → Calspar Division-Steelhead Resources Inc → Calspar Plant**

- 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

- **controller_controls_mine:** Steelhead Resources Ltd → Calspar Plant; 1986-02-11 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Calspar Division-Steelhead Resources Inc → Calspar Plant; 1986-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steelhead Resources Ltd → Calspar Division-Steelhead Resources Inc; 1986-07-01 to current/open; source msha-controller-operator-history