# Relationship history for MSHA mine 3605825

Current hierarchy: **David D  Svonavec → Casselman Coal Sales Company → Casselman Coal Prep 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Casselman Coal Sales Company → Casselman Coal Prep Plant; 1975-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David D  Svonavec et al → Casselman Coal Prep Plant; 1975-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David D  Svonavec et al → Casselman Coal Sales Company; 1975-01-01 to current/open; source msha-controller-operator-history