# Relationship history for MSHA mine 4405883

Current hierarchy: **M A Hanna Company; W R Grace Company → Paramont Coal Corp → Deep Mine #11**

- 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:** W R Grace Company et al → Deep Mine #11; 1981-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Paramont Coal Corp → Deep Mine #11; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W R Grace Company et al → Paramont Coal Corp; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** M A Hanna Company et al → Paramont Coal Corp; 1982-04-01 to current/open; source msha-controller-operator-history